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Sample records for sand point lake

  1. Coastal geology and recent origins for Sand Point, Lake Superior

    Science.gov (United States)

    Fisher, Timothy G.; Krantz, David E.; Castaneda, Mario R.; Loope, Walter L.; Jol, Harry M.; Goble, Ronald J.; Higley, Melinda C.; DeWald, Samantha; Hansen, Paul

    2014-01-01

    Sand Point is a small cuspate foreland located along the southeastern shore of Lake Superior within Pictured Rocks National Lakeshore near Munising, Michigan. Park managers’ concerns for the integrity of historic buildings at the northern periphery of the point during the rising lake levels in the mid-1980s greatly elevated the priority of research into the geomorphic history and age of Sand Point. To pursue this priority, we recovered sediment cores from four ponds on Sand Point, assessed subsurface stratigraphy onshore and offshore using geophysical techniques, and interpreted the chronology of events using radiocarbon and luminescence dating. Sand Point formed at the southwest edge of a subaqueous platform whose base is probably constructed of glacial diamicton and outwash. During the post-glacial Nipissing Transgression, the base was mantled with sand derived from erosion of adjacent sandstone cliffs. An aerial photograph time sequence, 1939–present, shows that the periphery of the platform has evolved considerably during historical time, infl uenced by transport of sediment into adjacent South Bay. Shallow seismic refl ections suggest slump blocks along the leading edge of the platform. Light detection and ranging (LiDAR) and shallow seismic refl ections to the northwest of the platform reveal large sand waves within a deep (12 m) channel produced by currents fl owing episodically to the northeast into Lake Superior. Ground-penetrating radar profi les show transport and deposition of sand across the upper surface of the platform. Basal radiocarbon dates from ponds between subaerial beach ridges range in age from 540 to 910 cal yr B.P., suggesting that Sand Point became emergent during the last ~1000 years, upon the separation of Lake Superior from Lakes Huron and Michigan. However, optically stimulated luminescence (OSL) ages from the beach ridges were two to three times as old as the radiocarbon ages, implying that emergence of Sand Point may have begun

  2. Sediment Source Fingerprinting of the Lake Urmia Sand Dunes.

    Science.gov (United States)

    Ahmady-Birgani, Hesam; Agahi, Edris; Ahmadi, Seyed Javad; Erfanian, Mahdi

    2018-01-09

    Aeolian sand dunes are continuously being discovered in inner dry lands and coastal areas, most of which have been formed over the Last Glacial Maximum. Presently, due to some natural and anthropogenic implications on earth, newly-born sand dunes are quickly emerging. Lake Urmia, the world's second largest permanent hypersaline lake, has started shrinking, vast lands comprising sand dunes over the western shore of the lake have appeared and one question has been playing on the minds of nearby dwellers: where are these sand dunes coming from, What there was not 15 years ago!! In the present study, the determination of the source of the Lake Urmia sand dunes in terms of the quantifying relative contribution of each upstream geomorphological/lithological unit has been performed using geochemical fingerprinting techniques. The findings demonstrate that the alluvial and the fluvial sediments of the western upstream catchment have been transported by water erosion and they accumulated in the lower reaches of the Kahriz River. Wind erosion, as a secondary agent, have carried the aeolian sand-sized sediments to the sand dune area. Hence, the Lake Urmia sand dunes have been originating from simultaneous and joint actions of alluvial, fluvial and aeolian processes.

  3. Water quality and bathymetry of Sand Lake, Anchorage, Alaska

    Science.gov (United States)

    Donaldson, Donald E.

    1976-01-01

    Sand Lake, a dimictic lowland lake in Anchorage, Alaska, has recently become as urban lake. Analyses indicate that the lake is oligotrophic, having low dissolved solids and nutrient concentrations. Snowmelt runoff from an adjacent residential area, however, has a dissolved-solids concentration 10 times that of the main body of Sand Lake. Lead concentrations in the runoff exceed known values from other water in the ANchorage area, including water samples taken beneath landfills. The volume of the snowmelt runoff has not been measured. The data presented can be used as a baseline for water-resource management. (Woodard-USGS)

  4. Study of Morphologic Change in Poyang Lake Basin Caused by Sand Dredging Using Multi-temporal Landsat Images and DEMs

    Science.gov (United States)

    Qi, S.; Zhang, X.; Wang, D.; Zhu, J.; Fang, C.

    2014-11-01

    Sand dredging has been practiced in rivers, lakes, harbours and coastal areas in recent years in China mostly because of demand from construction industry as building material. Sand dredging has disturbed aquatic ecosystems by affecting hydrological processes, increasing content of suspended sediments and reducing water clarity. Poyang Lake, connecting with Yangtze River in the lower reaches of the Yangtze River, is the largest fresh water lake in China. Sand dredging in Poyang Lake has been intensified since 2001 because such practice was banned in Yangtze River and profitable. In this study, the morphologic change caused by sand dredging in Poyang Lake basin was analysed by overlaying two DEMs acquired in 1952 and 2010 respectively. Since the reflectance of middle infrared band for sand dredging vessel is much higher than that of water surface, sand dredging vessels were showed as isolated grey points and can be counted in the middle infrared band in 12 Landsat images acquired in flooding season during 2000~2010. Another two Landsat images (with low water level before 2000 and after 2010) were used to evaluate the morphologic change by comparing inundation extent and shoreline shape. The following results was obtained: (1) vessels for sand dredging are mainly distributed in the north of Poyang Lake before 2007, but the dredging area was enlarged to the central region and even to Gan River; (2) sand dredging area reached to about 260.4 km2 and is mainly distributed in the north of Songmen Mountain and has been enlarged to central of Poyang Lake from the distribution of sand vessels since 2007. Sand dredged from Poyang Lake was about 1.99 × 109 m3 or 2448 Mt assuming sediment bulk density of 1.23 t m-3. It means that the magnitude of sand mining during 2001-2010 is almost ten times of sand depositions in Poyang Lake during 1955-2010; (3) Sand dredging in Poyang Lake has alternated the lake capacity and discharge section area, some of the watercourse in the

  5. [Imperial Oil's Cold Lake oil sands operations

    International Nuclear Information System (INIS)

    Dingle, H. B.

    1999-01-01

    Imperial Oil Limited's Cold Lake oil sands resources, production and operations in Alberta are discussed. Cold Lake is the company's largest single asset and its largest source of crude oil production. In 1998, Cold Lake accounted for just under half of Imperial's total liquid production, averaging more than 135,000 barrels of bitumen a day. Despite the very difficult operating conditions experienced by the oil sands industry in 1998, Imperial Oil's Cold Lake operations generated a positive cash flow and earnings. Just as important, the near and long-term potential of Cold Lake property continues to be strong, even with the tough market conditions today and the foreseeable future. Proved reserves at the end of 1997 were 1.3 billions barrels, equal to about 24 years of current production, but even more important is Imperial's resource base in the Athabasca region, which represents 150 years of production at current rates. Although production forecasts for the near future are are revised downward because of production shut-in due to low prices, the company is confident of its long-term prospects mainly because of existing infrastructure, superior reservoir quality, 30 years worth of operating improvements and established bitumen-blend markets. Details of the company's future Cold Lake development plans are discussed. The need to continue technology development, which has been at the core of the industry's growth in the past and will continue to be the key to the future, are emphasized

  6. Assessing the potential environmental impact of Athabasca oil sands development in lakes across Northwest Saskatchewan

    Science.gov (United States)

    Ahad, J. M.; Cumming, B. F.; Das, B.; Sanei, H.

    2011-12-01

    The continued development of Canada's Athabasca oil sands poses a significant environmental challenge. Low buffered boreal lakes located downwind of the prevailing eastward wind direction may be threatened by acidification and elevated inputs of airborne contaminants such as polycyclic aromatic hydrocarbons (PAHs). An accurate assessment of the impact that increased levels of bitumen production may have on lakes in the region requires an understanding of the historic variability within these systems prior to at least the past several decades. Here we report concentrations of PAHs, δ13C and δ15N of organic matter (OM), Rock-Eval pyrolysis analyses, and distributions of n-alkanes in dated sediment cores from ten lakes located across NW Saskatchewan. Concentrations of PAHs were relatively low (combustion of coniferous wood, was generally the most abundant PAH amongst those reported, demonstrating the importance of forest fires as a principal PAH source. Plots of Hydrogen Index (HI) versus Oxygen Index (OI) fell within a relatively narrow range typical for sediments containing a high content of algal-derived OM. Relatively lower C/N ratios and higher abundances of C17 n-alkane in more recent sediments pointed to an increasingly larger component of algal-derived OM. In all ten lakes δ13C showed gradual upcore depletions that fell within the expected range for fossil fuel combustion (i.e., Suess effect), although this alone may not explain the up to ~3% depletion observed in several of the lakes. In conjunction with the other upcore trends these data may suggest a possible increase in primary productivity over the past several decades in many of the lakes studied. δ15N signatures were more variable, showing upcore increases in some lakes and upcore depletions in others. The increasingly lighter values observed in more recent sediments in some lakes suggest a potential input of depleted bioavailable nitrogen, as might be expected from anthropogenic NOx emissions. This

  7. Geochemical behavior and dissolved species control in acid sand pit lakes, Sepetiba sedimentary basin, Rio de Janeiro, SE - Brazil

    Science.gov (United States)

    Marques, Eduardo D.; Sella, Sílvia M.; Bidone, Edison D.; Silva-Filho, Emmanoel V.

    2010-12-01

    This work shows the influence of pluvial waters on dissolved components and mineral equilibrium of four sand pit lakes, located in the Sepetiba sedimentary basin, SE Brazil. The sand mining activities promote sediment oxidation, lowering pH and increasing SO 4 contents. The relatively high acidity of these waters, similar to ore pit lakes environment and associated acid mine drainage, increases weathering rate, especially of silicate minerals, which produces high Al concentrations, the limiting factor for fish aquaculture. During the dry season, basic cations (Ca, Mg, K and Na), SiO 2 and Al show their higher values due to evapoconcentration and pH are buffered. In the beginning of the wet season, the dilution factor by rainwater increases SO 4 and decreases pH values. The aluminum monomeric forms (Al(OH) 2+ and Al(OH) 2+), the most toxic species for aquatic organisms, occur during the dry season, while AlSO 4+ species predominate during the wet season. Gibbsite, allophane, alunite and jurbanite are the reactive mineral phases indicated by PHREEQC modeling. During the dry season, hydroxialuminosilicate allophane is the main phase in equilibrium with the solution, while the sulphate salts alunite and jurbanite predominate in the rainy season due to the increasing of SO 4 values. Gibbsite is also in equilibrium with sand pit lakes waters, pointing out that hydrolysis reaction is a constant process in the system. Comparing to SiO 2, sulphate is the main Al retriever in the pit waters because the most samples (alunite and jurbanite) are in equilibrium with the solution in both seasons. This Al hydrochemical control allied to some precaution, like pH correction and fertilization of these waters, allows the conditions for fishpond culture. Equilibrium of the majority samples with kaolinite (Ca, Mg, Na diagrams) and primary minerals (K diagram) points to moderate weathering rate in sand pit sediments, which cannot be considered for the whole basin due to the anomalous

  8. Strategic assessment of the magnitude and impacts of sand mining in Poyang Lake, China

    NARCIS (Netherlands)

    Leeuw, de J.; Shankman, D.; Wu, G.; Boer, de W.F.; Burnham, J.; He, Q.; Yesou, H.; Xiao, J.

    2010-01-01

    Planning for the extraction of aggregates is typically dealt with at a case to case basis, without assessing environmental impacts strategically. In this study we assess the impact of sand mining in Poyang Lake, where dredging began in 2001 after sand mining in the Yangtze River had been banned. In

  9. Nourishment of perched sand dunes and the issue of erosion control in the Great Lakes

    Science.gov (United States)

    Marsh, William M.

    1990-09-01

    Although limited in coverage, perched sand dunes situated on high coastal bluffs are considered the most prized of Great Lakes dunes. Grand Sable Dunes on Lake Superior and Sleeping Bear Dunes on Lake Michigan are featured attractions of national lakeshores under National Park Service management. The source of sand for perched dunes is the high bluff along their lakeward edge. As onshore wind crosses the bluff, flow is accelerated upslope, resulting in greatly elevated levels of wind stress over the slope brow. On barren, sandy bluffs, wind erosion is concentrated in the brow zone, and for the Grand Sable Bluff, it averaged 1 m3/yr per linear meter along the highest sections for the period 1973 1983. This mechanism accounts for about 6,500 m3 of sand nourishment to the dunefield annually and clearly has been the predominant mechanism for the long-term development of the dunefield. However, wind erosion and dune nourishment are possible only where the bluff is denuded of plant cover by mass movements and related processes induced by wave erosion. In the Great Lakes, wave erosion and bluff retreat vary with lake levels; the nourishment of perched dunes is favored by high levels. Lake levels have been relatively high for the past 50 years, and shore erosion has become a major environmental issue leading property owners and politicians to support lake-level regulation. Trimming high water levels could reduce geomorphic activity on high bluffs and affect dune nourishment rates. Locally, nourishment also may be influenced by sediment accumulation associated with harbor protection facilities and by planting programs aimed at stabilizing dunes.

  10. Regional economic effects of current and proposed management alternatives for Sand Lake National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Lambert, Heather

    2005-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a Refuge and provide long range guidance and management direction to achieve Refuge purposes. Sand Lake National Wildlife Refuge (NWR), located 27 miles northeast of Aberdeen, South Dakota, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for Sand Lake NWR must contain an analysis of expected effects associated with current and proposed Refuge management strategies.

  11. Horizontal drilling in Miocene thin sand of Lake Maracaibo

    Energy Technology Data Exchange (ETDEWEB)

    Partidas, C. [PDVSA Exploration and Production (Venezuela)

    1998-12-31

    Horizontal drilling in the mature Lake Maracaibo field in Venezuela as a means of stimulating production are discussed. The Miocene sand where the horizontal well technology was applied, presented a number of intervals of unconsolidated sand of varied continuity, pay intervals at ten to twenty feet thickness, and reservoir pressures mostly at hydrostatic or below hydrostatic values. This paper evaluates a horizontal drilling program in the Lagunallis Lago Production Unit of Maracaibo, involving 91 wells to date (since 1995). When assessed in economic terms, results indicate that horizontal wells are a better economic alternative than vertical wells. The same results also showed that drainage from thin sand reservoirs resulted in better production with horizontal well technology than production from vertical wells. Payout was less than two years for 50 per cent of the horizontal wells while 40 per cent had payouts of between two and four years. Profit to investment ratio was greater than two in the case of about 70 per cent of the horizontal wells drilled in 1996. 2 tabs., 10 figs.

  12. Modelling assessment of oil sands pit lakes turn-over potential

    International Nuclear Information System (INIS)

    Mackenzie, I.; Vandenberg, J.; Lauzon, N.; Takyi, A.

    2006-01-01

    Pit lakes form when surface mining operations are discontinued and dewatering is terminated. Their use as a treatment step for oil sands surface mining reclamation waters was discussed. The goal of the End Pit Lake Subgroup of the Cumulative Environmental Management Association is to establish guidelines that will enable operators to achieve acceptable water quality for these lakes. Although both biological and physical processes affect turn-over potential, this presentation focused on the size of pit lakes, their depth, starting lake salinity concentrations, inflow rates and inflow salinity flux. These parameters where selected because of their influence on density gradients and turn-over potential. One-dimensional and two-dimensional modelling simulations were performed to examine turnover potential for a large range of pit lake configurations and conditions. The pit lake scenarios chosen for this modelling study included a wide range of changes in 3 lake sizes (1, 4 and 8 km 2 ), 3 lake depths (5, 20 and 50 m), 2 lake starting salinities (1 and 5 parts per thousand), 2 inflow rates (2 and 10 million m 3 per year), 3 starting inflow salinity concentrations (1, 2 and 4 parts per thousand) and 2 rates of influent salinity decrease (6- and 28- year half-life). Simulations showed that autumn is the governing season for determining turn-over potential. For the scenarios examined in this study, the expelling of salt from saline water upon ice formation and the effect of fresh water loading during spring melt events were not found to be significant factors governing turn-over potential. This presentation reviewed the DYRESM, CE-QUAL-W2, and RMA models used in this study. The conclusions reached by each model was also reviewed along with ongoing follow-up work

  13. Establishment of two invasive crustaceans (Copepoda: Harpacticoida) on the nearshore sands of Lake Michigan

    Science.gov (United States)

    Horvath, Thomas G.; Whitman, Richard L.; Last, Laurel L.

    2001-01-01

    Benthic copepods (Copepoda: Harpacticoida) in the nearshore sediments of southern Lake Michigan appear to be dominated by two new invasive species. We report the first occurrence in North America of Schizopera borutzkyi Montschenko, a native to the Danube River delta, and Heteropsyllus nr. nunni, likely a new species that is morphologically similar to the marine species Heteropsyllus nunni and represents the first occurrence of this genus in freshwater. Schizopera borutzkyi is a euryhaline species occurring in shallow sands in its native habitat and in deeper sands (6-15 m) in southern Lake Michigan. Based on the absence of these species from previous studies, we suggest that they are recent introductions. Heteropsyllus nr. nunni dominated (55-100%) the harpacticoid abundance to depths of 9 m, but S. borutzkyi comprised 75% of the harpacticoid abundance at 15 m. Native harpacticoids were always greatly outnumbered by invasive harpacticoids in our samples, which suggests that the natives are being replaced rapidly or that the invasive species are finding unused resources. The ecological implications of these introductions are not known, but these invasions may represent continued 'invasional meltdown' in Lake Michigan.

  14. Comparative growth models of big-scale sand smelt (Atherina boyeri Risso, 1810 sampled from Hirfanll Dam Lake, Klrsehir, Ankara, Turkey

    Directory of Open Access Journals (Sweden)

    S. Benzer

    2017-06-01

    Full Text Available In this current publication the growth characteristics of big-scale sand smelt data were compared for population dynamics within artificial neural networks and length-weight relationships models. This study aims to describe the optimal decision of the growth model of big-scale sand smelt by artificial neural networks and length-weight relationships models at Hirfanll Dam Lake, Klrsehir, Turkey. There were a total of 1449 samples collected from Hirfanll Dam Lake between May 2015 and May 2016. Both model results were compared with each other and the results were also evaluated with MAPE (mean absolute percentage error, MSE (mean squared error and r2 (coefficient correlation data as a performance criterion. The results of the current study show that artificial neural networks is a superior estimation tool compared to length-weight relationships models of big-scale sand smelt in Hirfanll Dam Lake.

  15. Perch population assessment in lakes reclaimed using oil-sands derived material

    International Nuclear Information System (INIS)

    Heuvel, M.R. van den; Dixon, D.G.; Power, M.; Boerger, H.; MacKinnon, M.D.; Meer, T. van

    1995-01-01

    The mining and extraction of petroleum products from oil-sands involves large areas of land and produces enormous volumes of tailings. One possible land reclamation option is to incorporate fine-tailings material into the bottoms of constructed lakes capped with natural surface water. The wet landscape method represents potential risk to aquatic biota-naphthenic acids and PAHs elute from pore water contained in the fine-tailings substrate. In spring 1995 yellow perch were stocked into a large-scale (5ha) experimental pond that consisted of fine-tailings capped with natural water as well as into two other reclaimed ponds that were constructed with oil-sands overburden material. Prior to stocking of perch, ponds had colonized with cyprinids, macrophytes and benthic invertebrates over a two year period. Perch were sampled in fall 1995 for age, condition factor, liver size, gonad size, fecundity, stomach contents, liver mixed-function oxygenase activity (MFO), bile PAH metabolites and plasma steroid hormones. When compared to the source lake, perch in the DP did not show reduced reproductive potential. Perch in all of the reclaimed ponds demonstrated exposure to organic compounds as indicated by marginally induced MFO activity and increased liver size. Exposure to naphthenates and PAHs in water as well as ecological environmental factors will be discussed

  16. Aeolian sands and buried soils in the Mecklenburg Lake District, NE Germany: Holocene land-use history and pedo-geomorphic response

    Science.gov (United States)

    Küster, Mathias; Fülling, Alexander; Kaiser, Knut; Ulrich, Jens

    2014-04-01

    The present study is a pedo-geomorphic approach to reconstructing Holocene aeolian sand dynamics in the Mecklenburg Lake District (NE Germany). Stratigraphical, sedimentological and soil research supplemented by morphogenetic interpretations of the genesis of dunes and aeolian sands are discussed. A complex Late Holocene aeolian stratigraphy within a drift sand area was developed at the shore of Lake Müritz. The results were confirmed using palynological records, archaeological data and regional history. Accelerated aeolian activity was triggered by the intensification of settlement and land-use activities during the 13th and in the 15th to 16th century AD. After a period of stability beginning with population decline during the ‘Thirty Years War' and continuing through the 18th century, a final aeolian phase due to the establishment of glassworks was identified during the 19th century AD. We assume a direct link between Holocene aeolian dynamics and human activities. Prehistoric Holocene drift sands on terrestrial sites have not been documented in the Mecklenburg Lake District so far. This might be explained either by erosion and incorporation of older aeolian sediments during younger aeolian phases and/or a lower regional land-use intensity in older periods of the Holocene. The investigated drift sands are stratigraphically and sedimentologically characterised by a high degree of heterogeneity, reflecting the spatial and temporal variability of Holocene human impact.

  17. Luminescence dose of sand by the huguangyan maar lake

    International Nuclear Information System (INIS)

    Xiong Zhengye; Chen Jinmin; Ding Ping; Shi Wenqing; Ma Weijiang; Zhu Jinhan

    2010-01-01

    Sand samples were collected at different locations from the Huguangyan Maar Lake region in Zhanjiang, Guangdong province in south China. Thermoluminescence (TL) and optical stimulated luminescence (OSL) were measured with coarse grain technique. The TL and OSL dose response were analyzed and their ancient doses were calculated. The result shows that ancient doses measured with TL technique differ from those measured with OSL technique for the same sample, whereas for the samples whose TL ancient dose is close to the veraciousness, there were no evident degree of difference between the ancient doses by OSL and TL. The experiments and analyses can be used for reference in Quaternary period volcano dating. (authors)

  18. 77 FR 63326 - Huron Wetland Management District, Madison Wetland Management District, and Sand Lake Wetland...

    Science.gov (United States)

    2012-10-16

    ..., consistent with sound principles of fish and wildlife management, conservation, legal mandates, and our... FXRS1265066CCP0] Huron Wetland Management District, Madison Wetland Management District, and Sand Lake Wetland Management District, SD; Final Comprehensive Conservation Plan and Finding of No Significant Impact for...

  19. Spatial and temporal patterns in trace element deposition to lakes in the Athabasca oil sands region (Alberta, Canada)

    Science.gov (United States)

    Cooke, Colin A.; Kirk, Jane L.; Muir, Derek C. G.; Wiklund, Johan A.; Wang, Xiaowa; Gleason, Amber; Evans, Marlene S.

    2017-12-01

    The mining and processing of the Athabasca oil sands (Alberta, Canada) has been occurring for decades; however, a lack of consistent regional monitoring has obscured the long-term environmental impact. Here, we present sediment core results to reconstruct spatial and temporal patterns in trace element deposition to lakes in the Athabasca oil sands region. Early mining operations (during the 1970s and 1980s) led to elevated V and Pb inputs to lakes located quality guidelines, and no spatial or temporal trends were observed in the frequency of guideline exceedence. Our results demonstrate that early mining efforts had an even greater impact on trace element cycling than has been appreciated previously, placing recent monitoring efforts in a critical long-term context.

  20. Sand Point, Alaska Tsunami Forecast Grids for MOST Model

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Sand Point, Alaska Forecast Model Grids provides bathymetric data strictly for tsunami inundation modeling with the Method of Splitting Tsunami (MOST) model....

  1. Initial geochemical characteristics of fluid fine tailings in an oil sands end pit lake

    Energy Technology Data Exchange (ETDEWEB)

    Dompierre, Kathryn A. [Department of Civil and Geological Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5A9 (Canada); Lindsay, Matthew B.J., E-mail: matt.lindsay@usask.ca [Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada); Cruz-Hernández, Pablo [Department of Geology, University of Huelva, Campus ‘El Carmen’, E-21071 Huelva (Spain); Halferdahl, Geoffrey M. [Environmental Research and Development, Syncrude Canada Limited, Edmonton, Alberta T6N 1H4 (Canada)

    2016-06-15

    Geochemical characteristics of fluid fine tailings (FFT) were examined in Base Mine Lake (BML), which is the first full-scale demonstration oil sands end pit lake (EPL) in northern Alberta, Canada. Approximately 186 Mm{sup 3} of FFT was deposited between 1994 and 2012, before BML was established on December 31, 2012. Bulk FFT samples (n = 588) were collected in July and August 2013 at various depths at 15 sampling sites. Temperature, solid content, electrical conductivity (EC), pH, Eh and alkalinity were measured for all samples. Detailed geochemical analyses were performed on a subset of samples (n = 284). Pore-water pH decreased with depth by approximately 0.5 within the upper 10 m of the FFT. Major pore-water constituents included Na (880 ± 96 mg L{sup −1}) and Cl (560 ± 95 mg L{sup −1}); Ca (19 ± 4.1 mg L{sup −1}), Mg (11 ± 2.0 mg L{sup −1}), K (16 ± 2.3 mg L{sup −1}) and NH{sub 3} (9.9 ± 4.7 mg L{sup −1}) were consistently observed. Iron and Mn concentrations were low within FFT pore water, whereas SO{sub 4} concentrations decreased sharply across the FFT–water interface. Geochemical modeling indicated that FeS{sub (s)} precipitation was favoured under SO{sub 4}-reducing conditions. Pore water was also under-saturated with respect to gypsum [CaSO{sub 4}·2H{sub 2}O], and near saturation with respect to calcite [CaCO{sub 3}], dolomite [CaMg(CO{sub 3}){sub 2}] and siderite [FeCO{sub 3}]. X-ray diffraction (XRD) suggested that carbonate-mineral dissolution largely depleted calcite and dolomite. X-ray absorption near edge structure (XANES) spectroscopy revealed the presence of FeS{sub (s)}, pyrite [FeS{sub 2}], and siderite. Carbonate-mineral dissolution and secondary mineral precipitation have likely contributed to FFT dewatering and settlement. However, the long-term importance of these processes within EPLs remains unknown. These results provide a reference for assessing the long-term geochemical evolution of oil sands EPLs, and offer

  2. Groundwater recharge estimates in the Athabasca and Cold Lake oil sands areas

    International Nuclear Information System (INIS)

    MacMillan, G.J.; Smith, A.D.

    2009-01-01

    Groundwater recharge estimates for the Cold Lake and Athabasca oil sands region were presented. New oil sands projects planned for the future will require approximately 150,000 m 3 per day of groundwater. Regulators and public agencies are now investigating the potential impacts of oil sands operations on both shallow groundwater and surface water in the region. Maximum yields from the aquifers are also being estimated. Measurements are currently being taken to determine transmissivity, hydraulic pressure, storage potential and leakage. Numerical models are currently used to determine saturated zone recharge estimates and water table fluctuations. Isotope tracers are also being used to determine where groundwater flow potential is vertical as well as to determine correction factors for hydrogeological and geochemical conditions at each site. Darcy's Law is used to determine heat flow in the groundwater aquifers. To date, the studies have demonstrated that drilling fluids have been recovered at groundwater sites. Wells are often installed near water supply and supply well networks. It was concluded that new water wells will need to be completed at various depths. Data were presented for aquifers and nest wells. refs., tabs., figs

  3. Responses of macroinvertebrates and local environment to short-term commercial sand dredging practices in a flood-plain lake.

    Science.gov (United States)

    Meng, Xingliang; Jiang, Xiaoming; Li, Zhengfei; Wang, Jun; Cooper, Keith M; Xie, Zhicai

    2018-08-01

    In parts of the developing world, the expansion of industrial sand mining activities has led to serious environmental concerns. However, current understanding of the effects of this activity on an inland water ecosystem remains limited. Herein, we choose the "most affected" lake in China (Dongting Lake), to assess short-term (1year) effects of sand dredging on key environmental parameters and on the structure of the macroinvertebrate assemblage. Within the dredged area we observed increases in water depth (on average 2.17m), turbidity and changes in sediment composition (e.g., increase in % medium sand, and a decrease in % clay). In addition, dredging was associated with a 50 % reduction in taxa richness, Simpson and Shannon-Wiener indices, and a 72 and 99 % reduction in abundance and biomass, respectively. Indirect effects were also observed in the zone surrounding the extraction sites (ca. 500m), most likely as a result of the dredging processes (e.g., sediment screening and overspill) and water flow. No such effects were observed at a nearby reference site. The direct removal of sediment and indirect alteration of physical conditions (e.g., water depth, turbidity and sediment composition) appear to be the most likely cause of variations in the benthic community. Implications of our findings for the planning, management and monitoring of sand dredging in inland waters are discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Remotely Sensing Lake Water Volumes on the Inner Arctic Coastal Plain of Northern Alaska

    Science.gov (United States)

    Simpson, C. E.; Arp, C. D.; Jones, B. M.; Hinkel, K. M.; Carroll, M.; Smith, L. C.

    2017-12-01

    Thermokarst lake depth is controlled by the amount of excess ice in near-surface permafrost, with lake depths of about 1 - 3 m in areas of epigenetic permafrost and over 10 m in areas of syngenetic permafrost. An important exception to these general patterns is found on the inner Arctic Coastal Plain (ACP) of northern Alaska, where deep lakes occur in Pleistocene-aged, ground-ice poor sandy terrain. These lakes cover 20% of the currently inactive sand sheet and dune deposit (referred to as the Pleistocene Sand Sea) that comprises approximately 7000 km2 of the ACP. Surrounded by high and eroding bluffs, sand sea lakes lie in natural depressions and are characterized by wide, shallow littoral shelves and central troughs that are typically oriented NNW to SSE and can reach depths greater than 20 m. Despite their unique form and extensive coverage, these lakes have received little prior study and a literature gap remains regarding regional water storage. This research classifies sand sea lakes, estimates individual lake volume, and provides a first quantification of water storage in a region of the lake-dominated ACP. We measured bathymetric profiles in 19 sand sea lakes using a sonar recorder to capture various lake depth gradients. Bathymetric surveys collected by oil industry consultants, lake monitoring programs, and habitat studies serve as additional datasets. These field measured lake depth data points were used to classify Color Infrared Photography, WorldView-2 satellite imagery, and Landsat-OLI satellite imagery to develop a spectral depth-classification algorithm and facilitate the interpolation of the bathymetry for study lakes in the inner ACP. Finally, we integrate the remotely sensed bathymetry and imagery-derived lake surface area to estimate individual and regional-scale lake volume. In addition to the natural function of these lakes in water storage, energy balance, and habitat provision, the need for winter water supply to build ice roads for oil

  5. Paleolimnological assessment of nutrient enrichment on diatom assemblages in a priori defined nitrogen- and phosphorus-limited lakes downwind of the Athabasca Oil Sands, Canada

    Directory of Open Access Journals (Sweden)

    Kathleen R. Laird

    2017-04-01

    Full Text Available As the industrial footprint of the Athabasca Oil Sands Region (AOSR continues to expand, concern about the potential impacts of pollutants on the surrounding terrestrial and aquatic ecosystems need to be assessed. An emerging issue is whether recent increases in lake production downwind of the development can be linked to AOSR activities, and/or whether changing climatic conditions are influencing lake nutrient status. To decipher the importance of pollutants, particularly atmospheric deposition of reactive nitrogen (Nr, and the effects of climate change as potential sources of increasing lake production, lakes from both within and outside of the nitrogen deposition zone were analyzed for historical changes in diatom assemblages. Lake sediment cores were collected from a priori defined nitrogen (N - and phosphorus (P - limited lakes within and outside the N plume associated with the AOSR. Diatom assemblages were quantified at sub-decadal resolution since ca. 1890 to compare conditions prior to oil sands expansion and regional climate warming, to the more recent conditions in each group of lakes (Reference and Impacted, N- and P-limited lakes. Analyses of changes in assemblage similarity and species turnover indicates that changes in diatom assemblages were minimal both within and across all lake groups.  Small changes in percent composition of planktonic taxa, particularly small centric taxa (Discostella and Cyclotella species and pennate taxa, such as Asterionella formosa and Fragilaria crotonensis, occurred in some of the lakes. While these changes were consistent with potential climate effects on algal growth, water column stability and other factors; the timing and direction of biotic changes were variable among sites suggesting that any apparent response to climate was lake dependent. The absence of a consistent pattern of diatom changes associated with receipt of reactive nitrogen or intrinsic nutrient-limitation status of the lake

  6. Study of the environmental impacts of the natural radioactivity presents in beach sand and Lake Sediment samples Idku, Behara, Egypt

    International Nuclear Information System (INIS)

    Fahmi, N.M.; El-Khatib, A.; Abd El-Salam, Y.M.; Naim, M.A.; Shalaby, M.H.; El-Gally, M.M.

    2011-01-01

    Natural radionuclides belonging to 232 Th, 238 U decay chains, 40 K and 137 Cs in contents of beach sands and bottom sediments collected at various locations over Idku coast and Idku lake, respectively have been determined using low background computerized high resolution gamma ray spectrometer. A distribution map for each radionuclide distribution was presented for idku lake as well as radium equivalent and the external hazard index which resulted from the natural radionuclides in sediments are also calculated and tabulated for the analyzed samples.

  7. Design overview of Syncrude's Mildred Lake East Toe berm

    International Nuclear Information System (INIS)

    List, B.R.; Martens, S.N.; Meyer, J.P.

    1999-01-01

    The Syncrude surface mining oil sand operation is located near Fort McMurray, Alberta, and produces an average of 470 tonnes of oil sand feed daily, which, after undergoing a bitumen extraction phase, generates 360,000 tonnes of tailings solids. This production yields approximately 83 million barrels of Syncrude Sweet Blend annually, being 13% of Canada's oil production. Tailings from the extraction process are used to hydraulically construct containment dikes and supporting beaches of the storage facilities, while the process water is returned to the extraction process. Since the start of the operation in 1978, the Mildred Lake Settling Basin has been Syncrude's primary tailings storage facility, and many design changes have occurred over 20 years which have optimized sand storage at the facility. An overview is included of the final design and preliminary performance of the Mildred Lake East Toe Berm currently being constructed along Cells 20 to 25 of Syncrude's Mildred Lake Settling Basin. The main point of constructing the East Toe Berm is to provide storage for 20 million cubic m or more of tailings over the period of March 1998 to July 1999. Following this period, a permanent tailings storage will be available in-pit. The key features of the Mildred Lake East Toe Berm described include the planning, design, and construction aspects, of which an additional benefit is an added storage capacity to the existing Mildred Lake Settling Basin. 6 refs., 8 figs., 3 tabs

  8. Modeling spatial variability of sand-lenses in clay till settings using transition probability and multiple-point geostatistics

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Nilsson, Bertel; Klint, Knud Erik

    2010-01-01

    (TPROGS) of alternating geological facies. The second method, multiple-point statistics, uses training images to estimate the conditional probability of sand-lenses at a certain location. Both methods respect field observations such as local stratigraphy, however, only the multiple-point statistics can...... of sand-lenses in clay till. Sand-lenses mainly account for horizontal transport and are prioritised in this study. Based on field observations, the distribution has been modeled using two different geostatistical approaches. One method uses a Markov chain model calculating the transition probabilities...

  9. Fort Hills Oil Sands Project No Net Loss Lake earthfill structure

    Energy Technology Data Exchange (ETDEWEB)

    Blakely, D.; Sawatsky, L. [Golder Associates Ltd., Calgary, AB (Canada); Wog, K.; Paz, S. [Alberta Environment, Edmonton, AB (Canada). Water Management Operations; Chernys, S. [Petro-Canada, Calgary, AB (Canada)

    2007-07-01

    The Fort Hills Oil Sands Project (FHOSP) is located north of Fort McMurray, Alberta. The Fort Hills Energy Corporation (FHEC) must compensate for fish habitat lost as a result of mine development that would disturb natural streams and lakes. FHEC planned to construct a fisheries compensation lake on the north end of its leased property, contained in part by an earthfill structure. Unlike most dam structures, the FHOSP No Net Loss Lake (NNLL) earthfill structure was planned solely for the creation of fisheries compensation habitat. Therefore, the NNLL earthfill structure must be designed with robust features that can handle any foreseeable environmental condition without failure, so that it may be accepted as a sustainable feature of the mine closure landscape. This paper discussed the design features of the NNLL earthfill structure. The paper presented information on the background of the project including regulatory criteria for the fisheries compensation habitat; fisheries compensation habitat location; and design criteria for the NNLL. The features of the NNLL earthfill structure were also discussed. In addition, the paper outlined the dam safety classification for earthfill structure and anticipated system performance. The proposed monitoring program and permanent closure plans were also discussed. It was concluded that the earthfill structure was designed with several features that would allow it to become a part of the closure landscape. These included a high width to height ratio, significant erosion protection, and an aggressive reclamation plan. These features will provide a sound basis for FHEC to apply for a reclamation certificate at the end of mine life. 3 refs., 3 tabs., 8 figs.

  10. 78 FR 9866 - Special Local Regulation; Moss Point Rockin' the Riverfront Festival; Robertson Lake & O'Leary...

    Science.gov (United States)

    2013-02-12

    ... 1625-AA08 Special Local Regulation; Moss Point Rockin' the Riverfront Festival; Robertson Lake & O... Riverfront Festival high speed boat races. Entry into, transiting or anchoring in this area is prohibited to... Point Rockin' the Riverfront Festival; Robertson Lake & O'Leary Lake; Moss Point, MS. (a) Location. The...

  11. Chemical mass transport between fluid fine tailings and the overlying water cover of an oil sands end pit lake

    Science.gov (United States)

    Dompierre, Kathryn A.; Barbour, S. Lee; North, Rebecca L.; Carey, Sean K.; Lindsay, Matthew B. J.

    2017-06-01

    Fluid fine tailings (FFT) are a principal by-product of the bitumen extraction process at oil sands mines. Base Mine Lake (BML)—the first full-scale demonstration oil sands end pit lake (EPL)—contains approximately 1.9 × 108 m3 of FFT stored under a water cover within a decommissioned mine pit. Chemical mass transfer from the FFT to the water cover can occur via two key processes: (1) advection-dispersion driven by tailings settlement; and (2) FFT disturbance due to fluid movement in the water cover. Dissolved chloride (Cl) was used to evaluate the water cover mass balance and to track mass transport within the underlying FFT based on field sampling and numerical modeling. Results indicated that FFT was the dominant Cl source to the water cover and that the FFT is exhibiting a transient advection-dispersion mass transport regime with intermittent disturbance near the FFT-water interface. The advective pore water flux was estimated by the mass balance to be 0.002 m3 m-2 d-1, which represents 0.73 m of FFT settlement per year. However, the FFT pore water Cl concentrations and corresponding mass transport simulations indicated that advection rates and disturbance depths vary between sample locations. The disturbance depth was estimated to vary with location between 0.75 and 0.95 m. This investigation provides valuable insight for assessing the geochemical evolution of the water cover and performance of EPLs as an oil sands reclamation strategy.

  12. 78 FR 23843 - Special Local Regulations; Moss Point Rockin' the Riverfront Festival; Robertson Lake & O'Leary...

    Science.gov (United States)

    2013-04-23

    ...-AA08 Special Local Regulations; Moss Point Rockin' the Riverfront Festival; Robertson Lake & O'Leary... Festival high speed boat races. Entry into, transiting or anchoring in this area is prohibited to all... Rockin' the Riverfront Festival; Robertson Lake & O'Leary Lake; Moss Point, MS. (a) Location. The...

  13. 77 FR 14963 - Special Local Regulation; Moss Point Rockin' the Riverfront Festival; O'Leary Lake; Moss Point, MS

    Science.gov (United States)

    2012-03-14

    ...-AA08 Special Local Regulation; Moss Point Rockin' the Riverfront Festival; O'Leary Lake; Moss Point, MS..., and persons on navigable waters during the Moss Point Rockin' the Riverfront Festival high speed boat... and vessels from safety hazards associated with the Moss Point Rockin' the Riverfront Festival high...

  14. Methane Fluxes and Consumption in an Oil Sands Tailings End Pit Lake

    Science.gov (United States)

    Slater, G. F.; Goad, C.; Arriaga, D.; Risacher, F.; Morris, P.; Lindsay, M. B.; Mumford, K. G.; Warren, L. A.

    2017-12-01

    End pit lakes are engineered freshwater lakes designed to reclaim land impacted by surface mining activities via establishment of a functioning ecosystem where biogeochemical cycling mitigates release of hazardous components either by stabilization or biodegradation. End pit lakes provide unique opportunities to gain insight into microbial nutrient cycling under extreme levels of impact that can be applicable to a range of levels of anthropogenic impacts and issues. This study focuses on microbial CH4 cycling in the underlying fluid fine tailings (FFT) and surface waters of Base Mine Lake (BML), the first full demonstration of end pit lake reclamation in the Athabasca Oil Sands Region (AOSR) of northern Alberta, Canada. Over two field seasons (2015 and 2016) BML was thermally stratified, turning over in spring and fall. Oxygen concentrations in the epilimnion (70 to 80 % saturation) decreased steeply through the metalimnion to 3% saturation in the hypolimnion. Conversely, CH4 concentrations were highest in the hypolimnion of BML (25 to 140 µM) with the highest values being observed at the FFT/Water interface. Concentrations decreased to 1-2 µM at the metalimnion and further decreased to < 0.5 µM in the epilimnion. CH4 δ13C in FFT porewater indicated production via fermentative pathways. FFT settlement and dewatering of 0.73 to 1.0 m/yr results in advection of an estimated 1x107 to 2x107 moles/yr CH4 into the surface water, circa an order of magnitude greater than the 3x106 moles/year estimated for molecular diffusion. Calculated fluxes of dissolved CH4 from the FFT into the hypolimnion were 4 orders of magnitude higher than those from the hypolimnion to the metalimnion, indicating a significant sink for CH4 within the hypolimnion limiting upward dissolved CH4 transport. Dissolution of CH4 from bubbles released from the FFT may be contributing to the observed epilimnion concentrations. CH4 δ13C in the hypolimnion showed only minimal enrichment with decreasing

  15. The chemical and biological evolution of mature fine tailings in oil sands end-pit lakes

    International Nuclear Information System (INIS)

    Chen, M.; Weisener, C.; Ciborowski, J.

    2010-01-01

    This presentation described an innovative bench-scale technique to characterize oil sand tailings and their impact on sediment oxygen demand (SOD) for future end-pit lake model behaviour. SOD is a dominant contributor to oxygen depletion in wetlands. The function and sustainability of a wetland ecosystem depends on the biochemical processes occurring at the sediment-water interface. The biochemical reactions associated with natural sediment can change with the addition of oil sands processed material (OSPM), which can affect SOD and ecosystem viability. It is important to establishing the biotic and abiotic controls of SOD. In order to evaluate the effectiveness of current wetland reclamation designs, it is important to establish the biotic and abiotic controls of SOD. The REDOX chemistry of fresh tailings sediment (MFT) was measured in this laboratory microcosm to determine the chemical and biological influences, and to study the role of developing microbial communities as new mature fine tailings (MFT) age. The study evaluated the changes in the main chemical, physical and biological populations of the MFT in both aerobic and anaerobic microcosms. A combination of microelectrode arrays and DNA profiling at the tailings water interface was used in the study.

  16. Riddle of the sands

    Energy Technology Data Exchange (ETDEWEB)

    Rolheiser, P

    1998-09-01

    A geological model of the Alberta landscape during the period stretching from about 110 million to 100 million years ago during the Cretaceous period when dinosaurs roamed the earth, was sketched. Today, the region contains the Cold Lake oil sands deposit. Imperial Oil began large-scale production at Cold Lake in 1985. The formations within the area are the source of almost half of Imperial Oil`s daily crude oil production and account for one in every 20 barrels of oil produced daily in Canada. The bitumen is produced using cyclic steam stimulation where steam is injected at high pressure into the underground reservoir, fracturing the sandstone and heating the bitumen it holds to thin it so that it can then flow through well bores to the surface. Conventional geological theory suggested that the Cold Lake reservoir was the remains of a prehistoric river delta. In 1994, Imperial Oil established a Cold Lake sequence stratigraphy project to verify this theory. This highly complex project involves volumes of geophysical well-log data from the 2,500 wells at Cold Lake, core samples cut from more than 600 of these wells and microscopic fossilized remains of 100-million-year-old flora extracted from the core samples, and seismic information. The interpreted data helps to create a three-dimensional model of the reservoir`s structure and help define its boundaries. Results have shown that the Cold Lake deposit was created from at least 13 intersecting river beds. Each of the rivers flowed for a few hundred thousand years and deposited sands of varying quality in different layers and patterns. The oil came about 40 million years later after the plant and animal materials containing hydrogen and carbon were broken down by heat and pressure to form oil. 1 fig.

  17. Localized enrichment of polycyclic aromatic hydrocarbons in soil, spruce needles, and lake sediments linked to in-situ bitumen extraction near Cold Lake, Alberta

    International Nuclear Information System (INIS)

    Korosi, J.B.; Irvine, G.; Skierszkan, E.K.; Doyle, J.R.; Kimpe, L.E.; Janvier, J.; Blais, J.M.

    2013-01-01

    The extraction of bitumen from the Alberta oil sands using in-situ technologies is expanding at a rapid rate; however, investigations into the environmental impacts of oil sands development have focused on surface mining in the Athabasca region. We measured polycyclic aromatic hydrocarbons (PAH) in soils, spruce needles, and lake sediment cores in the Cold Lake oil sands region to provide a historical and spatial perspective on PAH contamination related to in-situ extraction activities. A pronounced increase in PAH concentrations was recorded in one of two study lakes (Hilda Lake) corresponding to the onset of commercial bitumen production in ∼1985. Distance from extraction rigs was not an important predictor of PAH concentrations in soils, although two samples located near installations were elevated in alkyl PAHs. Evidence of localized PAH contamination in Hilda Lake and two soil samples suggests that continued environmental monitoring is justified to assess PAH contamination as development intensifies. -- Highlights: •In-situ bitumen extraction linked to rise in alkyl PAHs in one of two study lakes. •Alkyl PAHs elevated in two soil samples. •PAH contamination likely related to effluent sources, not atmospheric deposition. -- PAHs in sediments and soils were generally low in areas adjacent to in-situ bitumen extraction rigs in the Cold Lake Alberta oil sands, but evidence of localized contamination at some sites was evident

  18. 75 FR 55477 - Safety Zone; Revolution 3 Triathlon, Lake Erie & Sandusky Bay, Cedar Point, OH

    Science.gov (United States)

    2010-09-13

    ...-AA00 Safety Zone; Revolution 3 Triathlon, Lake Erie & Sandusky Bay, Cedar Point, OH AGENCY: Coast Guard... portions of the Lake Erie during the Revolution 3 Cedar Point Triathlon. The temporary safety zone is... 5 p.m., Monday through Friday, except Federal holidays. FOR FURTHER INFORMATION CONTACT: If you have...

  19. An approach to hydrogeological modeling of a large system of groundwater-fed lakes and wetlands in the Nebraska Sand Hills, USA

    Science.gov (United States)

    Rossman, Nathan R.; Zlotnik, Vitaly A.; Rowe, Clinton M.

    2018-05-01

    The feasibility of a hydrogeological modeling approach to simulate several thousand shallow groundwater-fed lakes and wetlands without explicitly considering their connection with groundwater is investigated at the regional scale ( 40,000 km2) through an application in the semi-arid Nebraska Sand Hills (NSH), USA. Hydraulic heads are compared to local land-surface elevations from a digital elevation model (DEM) within a geographic information system to assess locations of lakes and wetlands. The water bodies are inferred where hydraulic heads exceed, or are above a certain depth below, the land surface. Numbers of lakes and/or wetlands are determined via image cluster analysis applied to the same 30-m grid as the DEM after interpolating both simulated and estimated heads. The regional water-table map was used for groundwater model calibration, considering MODIS-based net groundwater recharge data. Resulting values of simulated total baseflow to interior streams are within 1% of observed values. Locations, areas, and numbers of simulated lakes and wetlands are compared with Landsat 2005 survey data and with areas of lakes from a 1979-1980 Landsat survey and the National Hydrography Dataset. This simplified process-based modeling approach avoids the need for field-based morphology or water-budget data from individual lakes or wetlands, or determination of lake-groundwater exchanges, yet it reproduces observed lake-wetland characteristics at regional groundwater management scales. A better understanding of the NSH hydrogeology is attained, and the approach shows promise for use in simulations of groundwater-fed lake and wetland characteristics in other large groundwater systems.

  20. On the origin of calcite-cemented sandstones in the clearwater formation oil-sands, Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Colquhoun, I.M.

    1999-01-01

    This thesis examined the formation of calcite-cemented sandstones in the Clearwater Formation within the Cold Lake and southern Primrose areas of the Alberta oil sands. Three stages of diagenesis have been recognized, both in the calcite-cemented sandstones and reservoir sands. Diagenesis of the Clearwater Formation in the Cold Lake and southern Primrose areas ended once the reservoir filled with hydrocarbons, but in the Cold Lake area, diagenesis of water-saturated sands likely continued after hydrocarbon emplacement. The reservoir sands in the formation contain a diverse clay mineral assemblage. In general, 0.7 nm clays dominate the diagenetic clay mineralogy of the Clearwater sands. Reservoir sands that contain large amounts of detrital clays and early diagenetic, grain-coating chlorite/smectite have significantly reduced bitumen-saturation. The presence of detrital and diagenetic smectitic clays complicates the removal of bitumen from the Clearwater formation using cyclic steam stimulation techniques because they swell during steam stimulation and reduce porosity and permeability of reservoir sands. Reservoir sands that contain kaolinite, feldspar and calcite react to form smectitic clays, which swell upon cyclic steam stimulation and further reduce porosity and permeability of reservoir sands. However, in the Cold Lake and Primrose areas, the dominant clay mineral is berthierine, which is associated with high calcite, which help to preserve porosity, permeability and bitumen saturation. The porous nature of bitumen-saturated, calcite-cemented sandstones that are laterally extensive could possibly provide a preferential path for steam to initiate calcite dissolution and produce significant concentrations of dissolved carbon dioxide in injected fluids. It was noted that this may then precipitate as carbonate scale within the reservoir and could cause formation damage or affect production equipment. 207 refs., 9 tabs., 58 figs., 3 appendices.

  1. Bituminous sands : tax issues

    International Nuclear Information System (INIS)

    Patel, B.

    2004-01-01

    This paper examined some of the tax issues associated with the production of bitumen or synthetic crude oil from oil sands. The oil sands deposits in Alberta are gaining more attention as the supplies of conventional oil in Canada decline. The oil sands reserves located in the Athabasca, Cold Lake and Peace River areas contain about 2.5 trillion barrels of highly viscous hydrocarbons called bitumen, of which nearly 315 billion barrels are recoverable with current technology. The extraction method varies for each geographic area, and even within zones and reservoirs. The two most common extraction methods are surface mining and in-situ extraction such as cyclic steam stimulation (CSS); low pressure steam flood; pressure cycle steam drive; steam assisted gravity drainage (SAGD); hot water flooding; and, fire flood. This paper also discussed the following general tax issues: bituminous sands definition; bituminous sands leases and Canadian development expense versus Canadian oil and gas property expense (COGPE); Canadian exploration expense (CEE) for surface mining versus in-situ methods; additional capital cost allowance; and, scientific research and experimental development (SR and ED). 15 refs

  2. Sand transportation and reverse patterns over leeward face of sand dune

    Science.gov (United States)

    Jiang, Hong; Dun, Hongchao; Tong, Ding; Huang, Ning

    2017-04-01

    Sand saltation has complex interactions with turbulent flow and dune form. Most models of wind-blown sand consider ideal circumstances such as steady wind velocity and a flat surface, and the bulk of data on wind flow and sand transport over an individual dune has focused mostly on the influence of dune shape or inter-dune space on the wind flow, neglecting the effect of morphology on sand saltation, particularly airflow and sand transportation over the leeward slope. Wind flow structures over the leeward slope of sand dunes have a fundamental influence on the organization of sand dunes. In order to understand sand dune dynamics, lee face airflow and sediment transportation should be paid more attention. Previous field observations could not measure turbulent flow structure well because of the limited observation points and the influence of experiment structure on wind field. In addition, the reverse sand particles over leeward face could not be collected by sand trap in field. Numerous field observations could not measure turbulent flow structure because of the limited observation points and the influence of experimental structures on the wind field. In addition, the reverse transport of sand particles over leeward face could not be collected by sand traps in field. Therefore, this paper aims to investigate the turbulent flow structure and sand transport pattern over the leeward slope. A numerical model of sand saltation over slope terrain is constructed, which also considers the coupling effects between air flow and sand particles. The large eddy simulation method is used to model turbulent flow. Sand transport is simulated by tracking the trajectory of each sand particle. The results show that terrain significantly alters the turbulent air flow structure and wind-blown sand movement, especially over the leeward slope. Here, mass flux increases initially and then decreases with height in the reversed flow region in the direction of wind flow, and the mass flux

  3. The effects of season and sand mining activities on thermal regime and water quality in a large shallow tropical lake.

    Science.gov (United States)

    Sharip, Zati; Zaki, Ahmad Taqiyuddin Ahmad

    2014-08-01

    Thermal structure and water quality in a large and shallow lake in Malaysia were studied between January 2012 and June 2013 in order to understand variations in relation to water level fluctuations and in-stream mining activities. Environmental variables, namely temperature, turbidity, dissolved oxygen, pH, electrical conductivity, chlorophyll-A and transparency, were measured using a multi-parameter probe and a Secchi disk. Measurements of environmental variables were performed at 0.1 m intervals from the surface to the bottom of the lake during the dry and wet seasons. High water level and strong solar radiation increased temperature stratification. River discharges during the wet season, and unsustainable sand mining activities led to an increased turbidity exceeding 100 NTU, and reduced transparency, which changed the temperature variation and subsequently altered the water quality pattern.

  4. Non-point Source Pollutants Loss of Planting Industry in the Yunnan Plateau Lake Basin, China

    Directory of Open Access Journals (Sweden)

    ZHAO Zu-jun

    2017-12-01

    Full Text Available Non-point source pollution of planting has become a major factor affecting the quality and safety of water environment in our country. In recent years, some studies show that the loss of nitrogen and phosphorus in agricultural chemical fertilizers has led to more serious non-point source pollution. By means of the loss coefficient method and spatial overlay analysis, the loss amount, loss of strength and its spatial distribution characteristics of total nitrogen, total phosphorus, ammonium nitrogen and nitrate nitrogen were analyzed in the Fuxian Lake, Xingyun Lake and Qilu Lake Basin in 2015. The results showed that:The loss of total nitrogen was the highest in the three basins, following by ammonium nitrogen, nitrate nitrogen and total phosphorus, which the loss of intensity range were 2.73~22.07, 0.003~3.52, 0.01~2.25 kg·hm-2 and 0.05~1.36 kg·hm-2, respectively. Total nitrogen and total phosphorus loss were mainly concentrated in the southwest of Qilu Lake, west and south of Xingyun Lake. Ammonium nitrogen and nitrate nitrogen loss mainly concentrated in the south of Qilu Lake, south and north of Xingyun Lake. The loss of nitrogen and phosphorus was mainly derived from cash crops and rice. Therefore, zoning, grading and phased prevention and control schemes were proposed, in order to provide scientific basis for controlling non-point source pollution in the study area.

  5. Process of extracting oil from stones and sands. [heating below cracking temperature and above boiling point of oil

    Energy Technology Data Exchange (ETDEWEB)

    Bergfeld, K

    1935-03-09

    A process of extracting oil from stones or sands bearing oils is characterized by the stones and sands being heated in a suitable furnace to a temperature below that of cracking and preferably slightly higher than the boiling-point of the oils. The oily vapors are removed from the treating chamber by means of flushing gas.

  6. Statistical Analysis of 3-Point Bending Properties of Polymer Concretes Made From Marble Powder Waste, Sand Grains, and Polyester Resin

    Science.gov (United States)

    Benzannache, N.; Bezazi, A.; Bouchelaghem, H.; Boumaaza, M.; Amziane, S.; Scarpa, F.

    2018-01-01

    The mechanical performance of concrete polymer beams subjected to 3-point bending was investigated. The polymer concrete incorporates marble powder waste and quarry sand. The results obtained showed that the type of sand, and amount of marble powder and sand aggregate affected the resistance of the polymer concrete beams significantly. The marble waste increased their bending strength by reducing the porosity of polymer concrete.

  7. White Sands, New Mexico as seen from STS-60

    Science.gov (United States)

    1994-01-01

    White Sands National Monument (Park) is easily recognized in the center of this near-vertical color photograph. White Sands is the world's largest gypsum dune field. It represents an alabaster sea that covers nearly 300 square miles. At the southwest corner of the White Sands is dry lake, Lucero. In terms of cultural features the city of Alamogordo and Holloman Air Force Base can be seen with great clarity on this photograph.

  8. contaminant migration in a sand aquifer near an inactive uranium tailings impoundment, Elliot Lake, Ontario

    International Nuclear Information System (INIS)

    Morin, K.A.; Cherry, J.A.

    1982-01-01

    An investigation of the movement of contaminated groundwater from inactive uranium tailings through a sand aquifer is being conducted at the Nordic Main tailings impoundment near Elliot Lake, Ontario. During 1979 and 1980, multilevel bundle-type piezometers were installed at several locations around the edge of the tailings impoundment. Chemical analysis of water samples from the bundle piezometers indicate that a major contaminant plume extends outward through a sand aquifer from the southeastern part of the Nordic Main impoundment dam. In the vincinity of the contaminant plume, the sand aquifer varies in thickness from about 9 to 15 m. The plume has two distinct segments, referred to as the inner core and the outer zone. The inner core, which has a pH of 4.3-5.0 and extends about 15 m from the foot of the tailings dam, contains several grams per litre of iron and sulfate, and tens of pCi/L of 226 Ra and 210 Pb. Water levels in piezometers within the inner core show that groundwater is moving horizontally, away from the tailings impoundment, with a velocity of up to several hundred metres per year. The outer zone, which extends a few hundred metres downgradient from the dam, is characterized by hundreds to thousands of milligrams per litre of iron and sulfate, less than 15pCi/L of 226 Ra, and a pH greater than 5.7. Comparison of 1979 and 1980 data shows that the front of the inner core is advancing a few metres per year, which is less than a few percent of the groundwater velocity. This retardation of movement of the inner core is caused by neutralization of the acidic water as a result of dissolution of calcium carbonate in the sand. With the rise in pH, precipitation of iron carbonate and possibly some iron hydroxide occurs and the contaminants of main concern such as 226 Ra, 210 Pb, and uranium are removed from solution by adsorption or coprecipitation

  9. PIXE analysis of sand and soil from Ulaanbaatar and Karakurum, Mongolia

    Science.gov (United States)

    Markwitz, A.; Barry, B.; Shagjjamba, D.

    2008-09-01

    Twenty-one sand and soil samples were collected at the surface from 22 to 25 June 2007 at sampling sites from Ulaanbaatar to Karakurum, Mongolia. The sand samples were collected from constantly changing sand dunes which may still contain salt from prehistoric oceans. The dry sand and soil samples were processed for PIXE and PIGE analyses. A clear division between soils and sand become apparent in the silicon results. Concentrations of all bulk elements in human habitation samples and of Si, Al, K and Fe in dry lake/flood plain samples are similar to those in the soils and sands. Among elements which could be regarded as being at trace concentrations the average S concentration in the soils is 0.9 g kg-1 whereas it is not detected in the sand samples. Zinc and Cu concentrations are both higher in the soils than the sands and are strongly correlated. A surprising presence of uranium at a concentration of 350 mg kg-1 was detected in the PIXE measurement on one of the dry lake samples. Gamma spectrometry confirmed the presence of U in this sample and also at a lower level in a sample from the lake shore, but in none of the other samples. Further, the gamma spectrometry showed that 238U decay products were present only at a level corresponding to about 3 mg kg-1 U for a system in radioactive equilibrium, a figure which is typical for U in the earth's crust. Disequilibria between 238U and its decay products occur naturally but such a high degree of separation at high concentration would be unique if confirmed. PIXE and PIGE measurements of these samples highlight the difficulty in correlating trace element measurements with occurrence of indicators of sea salt in air particulate samples.

  10. Wapan Sakahikan : the making of a lake

    Energy Technology Data Exchange (ETDEWEB)

    Jaremko, D.

    2009-08-15

    This article discussed an ecosystem project built on reclaimed oil sands lands. The oil sands mine originally required the removal of sections of the Tar and Calumet rivers, tributaries of the Athabasca River. A 76.7 hectare lake was constructed in order to salvage over 100,000 fish. The reclamation included the development of a traditional gathering area for local First Nations and Metis. The lake included a variety of fish habitats and was supported by 5 years of monitoring. The lake will be home to 8 fish species and is 23 meters in depth with shallow areas of 5 meters. Biologists helped to build the habitats, which include deep channels with varying depth and widths; shoals; overhead vegetation; and a rearing habitat area. The lake's littoral zone is approximately 30 per cent of the lake's total area. The involvement of First Nations and Metis included a traditional ceremony on the empty lake bottom. 1 fig.

  11. Timing of lake-level changes for a deep last-glacial Lake Missoula: optical dating of the Garden Gulch area, Montana, USA

    Science.gov (United States)

    Smith, Larry N.; Sohbati, Reza; Buylaert, Jan-Pieter; Lian, Olav B.; Murray, Andrew; Jain, Mayank

    2018-03-01

    Glaciolacustrine sediments in the Clark Fork River valley at Garden Gulch, near Drummond, Montana, USA record highstand positions of the ice-dammed glacial Lake Missoula and repeated subaerial exposure. During these highstands the lake was at greater than 65% of its recognized maximum capacity. The initial lake transgression deposited a basal sand unit. Subsequent cycles of lake-level fluctuations are recorded by sequences of laminated and cross laminated silt, sand, and clay deformed by periglacial processes during intervening periods of lower lake levels. Optically stimulated luminescence (OSL) dating of quartz sand grains, using single-aliquot regenerative-dose procedures, was carried out on 17 samples. Comparison of infrared stimulated luminescence (IRSL) from K-rich feldspar to OSL from quartz for all the samples suggests that they were well bleached prior to deposition and burial. Ages for the basal sand and overlying glaciolacustrine exposure surfaces are indistinguishable within one standard deviation, and give a weighted mean age of 20.9 ± 1.3 ka (n = 11). Based on sedimentological and stratigraphic analysis we infer that the initial transgression, and at least six cycles of lake-level fluctuation, occurred over time scales of decades to ∼2 ka. Bioturbated sandy slopewash dated at 10.6 ± 0.9 ka and 11.9 ± 1.2 ka unconformably overlies the upper glaciolacustrine deposits. The uppermost sediments, above the glaciolacustrine section, are younger than the Glacier Peak tephra (13.7-13.4 cal ka B.P.), which was deposited across parts of the drained lake basin, but has not been found at Garden Gulch. Our study indicates that glacial Lake Missoula reached >65 percent of maximum capacity by about 20.9 ± 1.3 ka and either partially or completely drained twelve times from this position. Rapid lowering from the lake's highstand position due to ice-dam failure likely led to scour in the downstream portions of the glacial Lake Missoula basin and megafloods in the

  12. The Key Lake project

    International Nuclear Information System (INIS)

    1991-01-01

    Key Lake is located in the Athabasca sand stone basin, 640 kilometers north of Saskatoon, Saskatchewan, Canada. The three sources of ore at Key Lake contain 70 100 tonnes of uranium. Features of the Key Lake Project were described under the key headings: work force, mining, mill process, tailings storage, permanent camp, environmental features, worker health and safety, and economic benefits. Appendices covering the historical background, construction projects, comparisons of western world mines, mining statistics, Northern Saskatchewan surface lease, and Key Lake development and regulatory agencies were included

  13. Recent Warming, Rather than Industrial Emissions of Bioavailable Nutrients, Is the Dominant Driver of Lake Primary Production Shifts across the Athabasca Oil Sands Region.

    Directory of Open Access Journals (Sweden)

    Jamie C Summers

    Full Text Available Freshwaters in the Athabasca Oil Sands Region (AOSR are vulnerable to the atmospheric emissions and land disturbances caused by the local oil sands industry; however, they are also affected by climate change. Recent observations of increases in aquatic primary production near the main development area have prompted questions about the principal drivers of these limnological changes. Is the enhanced primary production due to deposition of nutrients (nitrogen and phosphorus from local industry or from recent climatic changes? Here, we use downcore, spectrally-inferred chlorophyll-a (VRS-chla profiles (including diagenetic products from 23 limnologically-diverse lakes with undisturbed catchments to characterize the pattern of primary production increases in the AOSR. Our aim is to better understand the relative roles of the local oil sands industry versus climate change in driving aquatic primary production trends. Nutrient deposition maps, generated using geostatistical interpolations of spring-time snowpack measurements from a grid pattern across the AOSR, demonstrate patterns of elevated total phosphorus, total nitrogen, and bioavailable nitrogen deposition around the main area of industrial activity. However, this pattern is not observed for bioavailable phosphorus. Our paleolimnological findings demonstrate consistently greater VRS-chla concentrations compared to pre-oil sands development levels, regardless of morphological and limnological characteristics, landscape position, bioavailable nutrient deposition, and dibenzothiophene (DBT-inferred industrial impacts. Furthermore, breakpoint analyses on VRS-chla concentrations across a gradient of DBT-inferred industrial impact show limited evidence of a contemporaneous change among lakes. Despite the contribution of bioavailable nitrogen to the landscape from industrial activities, we find no consistency in the spatial pattern and timing of VRS-chla shifts with an industrial fertilizing signal

  14. Ground-water availability in the central part of Lake Ontario basin, New York

    Science.gov (United States)

    Miller, Todd S.; Krebs, Martha M.

    1988-01-01

    A set of three maps showing surficial geology, distribution of glacial aquifers, and potential well yield in the 708 sq mi central part of the Lake Ontario basin are presented at a scale of 1:125,000. The basin is parallel to Lake Ontario and extends from Rochester in the west to Oswego in the east. Aquifers consisting primarily of sand and gravel formed where meltwaters from glaciers deposited kame and outwash sand and gravel and where wave action along shores of glacial lakes eroded, reworked , and deposited beaches. Thick deposits of well-sorted sand and gravel yield relatively large quantities of water - typically more than 100 gal/min. Aquifers consisting of thin beds of sand and (or) gravel or thick gravel that contain a large proportion of silt and fine sand yield moderate amounts of water, 10 to 100 gal/min. Dug and driven wells that tap fine to medium sand deposits typically yield 1 to 10 gal/min. (USGS)

  15. Improving Multi-Objective Management of Water Quality Tipping Points: Revisiting the Classical Shallow Lake Problem

    Science.gov (United States)

    Quinn, J. D.; Reed, P. M.; Keller, K.

    2015-12-01

    Recent multi-objective extensions of the classical shallow lake problem are useful for exploring the conceptual and computational challenges that emerge when managing irreversible water quality tipping points. Building on this work, we explore a four objective version of the lake problem where a hypothetical town derives economic benefits from polluting a nearby lake, but at the risk of irreversibly tipping the lake into a permanently polluted state. The trophic state of the lake exhibits non-linear threshold dynamics; below some critical phosphorus (P) threshold it is healthy and oligotrophic, but above this threshold it is irreversibly eutrophic. The town must decide how much P to discharge each year, a decision complicated by uncertainty in the natural P inflow to the lake. The shallow lake problem provides a conceptually rich set of dynamics, low computational demands, and a high level of mathematical difficulty. These properties maximize its value for benchmarking the relative merits and limitations of emerging decision support frameworks, such as Direct Policy Search (DPS). Here, we explore the use of DPS as a formal means of developing robust environmental pollution control rules that effectively account for deeply uncertain system states and conflicting objectives. The DPS reformulation of the shallow lake problem shows promise in formalizing pollution control triggers and signposts, while dramatically reducing the computational complexity of the multi-objective pollution control problem. More broadly, the insights from the DPS variant of the shallow lake problem formulated in this study bridge emerging work related to socio-ecological systems management, tipping points, robust decision making, and robust control.

  16. Use of pre-industrial floodplain lake sediments to establish baseline river metal concentrations downstream of Alberta oil sands: a new approach for detecting pollution of rivers

    International Nuclear Information System (INIS)

    Wiklund, Johan A; Hall, Roland I; Farwell, Andrea J; George Dixon, D; Wolfe, Brent B; Edwards, Thomas WD

    2014-01-01

    In the Alberta oil sands region, insufficient knowledge of pre-disturbance reference conditions has undermined the ability of the Regional Aquatics Monitoring Program (RAMP) to detect pollution of the Athabasca River, because sampling began three decades after the industry started and the river naturally erodes oil-bearing strata. Here, we apply a novel approach to characterize pre-industrial reference metal concentrations in river sediment downstream of Alberta oil sands development by analyzing metal concentrations in sediments deposited in floodplain lakes of the Athabasca Delta during 1700–1916, when they were strongly influenced by Athabasca River floodwaters. We compared results to metal concentrations in surficial bottom sediments sampled by RAMP (2010–2013) at downstream sites of the Athabasca River and distributaries. When normalized to lithium content, concentrations of vanadium (a metal of concern in the oil sands region) and other priority pollutants (Be, Cd, Cr, Cu, Pb, Ni, Zn) in nearly all of the RAMP river sediment samples lie below the upper 95% prediction interval linearly extrapolated from the river-derived lake sediments. Assuming the RAMP protocols obtained recently deposited sediment, this indicates that the metal concentrations in downstream Athabasca River sediment have not increased above pre-disturbance levels. Reference conditions derived from the lake sediment data were used to develop profiles of metal residual concentrations versus time for the RAMP river sediment data, which provides an excellent tool for decision-makers to identify and quantify levels of metal pollution for any given sample, and to monitor for future trends. We recommend that the approach be applied to resurrect the utility of RAMP data at other river sampling locations closer to the development, and for ongoing risk assessment. The approach is also readily transferable to other rivers where insufficient pre-disturbance reference data impairs an ability to

  17. 77 FR 51912 - Safety Zone; Tom Lyons Productions Fireworks, Long Island Sound, Sands Point, NY

    Science.gov (United States)

    2012-08-28

    ... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 165 [Docket Number USCG-2012-0618] RIN 1625-AA00 Safety Zone; Tom Lyons Productions Fireworks, Long Island Sound, Sands Point, NY AGENCY.... 165.T01-0618 to read as follows: Sec. 165.T01-0618 Safety Zone; Tom Lyons Productions Fireworks, Long...

  18. Petrology of the Fort Smith - Great Slave Lake radiometric high near Pilot Lake, N.W.T

    International Nuclear Information System (INIS)

    Burwash, R.A.; Cape, D.F.

    1981-01-01

    Near Pilot Lake, the east boundary of the Fort Smith - Great Slave Lake radiometric high coincides with the contact of a well-foliated, porphyroblastic microcline-plagioclase-quartz-garnet-biotite gneiss (Pilot Lake Gneiss) with a hybrid assemblage of quartzite, mica schist, garnet-cordierite gneiss, and minor amphibolite (Variable Paragneiss). Anomalously high concentrations of uranium and thorium are associated with mafic-rich, lenticular bodies with a mineral assemblage biotite + monazite + zircon + ilmenite + hematite +- plagioclase +- quartz, within both the Variable Paragneiss and the Pilot Lake Gneiss. Corundum and spinel occur in the mafic lenses and sillimanite, kyanite, and hypersthene in other inclusions of the Pilot Lake Gneiss. The ilmenite-magnetite--monazite-zircon-apatite assemblage is interpreted as a 'black sand' concentration in a clastic sedimentary sequence subsequently metamorphosed by a regional granulite facies event. A granite pluton intruded during the same orogenic cycle assimilated the clastic metasedimentary rocks containing black sand interlayers, becoming enriched in thorium from the monazite. A second metamorphic event at lower P-T conditions, accompanied by strong cataclasis, developed the texture of the Pilot Lake Gneiss as now observed. Shearing within the gneiss locally concentrated hematite + quartz + uranium. Regional tectonic extrapolations suggest that the pyroxene granulite event was Kenoran and the later amphibolite event Hudsonian. (author)

  19. Investigation of soil properties for identifying recharge characteristics in the Lake Chad Basin

    Science.gov (United States)

    Banks, M. L.; Ndunguru, G. G.; Adisa, S. J.; Lee, J.; Adegoke, J. O.; Goni, I. B.; Grindley, J.; Mulugeta, V.

    2009-12-01

    Lake Chad was once labeled as one of the largest fresh water lakes in the world, providing water and livelihood to over 20 million people. The lake is shared by six different countries; Chad Nigeria, Niger, Cameroon, Central African Republic, and Sudan. Since the 1970 to date, a significant decrease in the size of the lake has been observed with the use of satellite imagery. This shrinking of the lake has been blamed on global warming, population increase and poor water management by the agriculture industry for farming purpose for both plants and animals. While these can be all valid reasons for the decrease of Lake Chad, we see the need to examine environmental and hydrological evidence around the Lake Chad basin. This study was carried out from upper stream to lower stream leading from Kano to the Damatru region which is one of several water bodies that supply Lake Chad. Over seventy six sites were sampled for soil texture, bulk density and other physical properties to investigate recharge capacity of the basin especially along the stream. Soils were collected using a soil core and properly stored at 4 degrees Celsius. Soils were weighed and put to dry at 105 degrees for twenty four hours. Dry weight was recorded and bulk density was calculated. The wet sieve method was used to determine the particle size analysis. Soils were weighed to 10 grams and hydrogen peroxide added to separate particles. Samples were washed with water and put to dry overnight. Soils were reweighed and sieved to separate as course sand, fine sand and silt and clay. The data revealed that in the upstream, coarse sand continuously decreased while silt and clay continuously increased down toward the lake. At mid stream silt and clay had significantly higher values when compared to coarse sand and fine sand. In the lower stream, bulk density clearly decreased compared to the upper and mid streams. Correlations will be carried out to investigate the particle size analysis and bulk density with

  20. Aging effects on oil-contaminated Kuwaiti sand

    International Nuclear Information System (INIS)

    Al-Sanad, H.A.; Ismael, N.F.

    1997-01-01

    Large quantities of oil-contaminated sands resulted from the destruction of oil wells and the formation of oil lakes in Kuwait at the end of the Gulf Wa/r. A laboratory testing program was carried out to determine the geotechnical properties of this material and the effect of aging on their properties. Tests included direct shear, triaxial, and consolidation tests on clean and contaminated sand at the same relative density. The influence of aging was examined by testing uncontaminated sand after aging for one, three, and six months in natural environmental conditions. The results indicated increased strength and stiffness due to aging and a reduction of the oil content due to evaporation of volatile compounds. The factors that influence the depth of oil penetration in compacted sand columns were also examined including the type of oil, relative density, and the amount of fines

  1. Japan's involvement in oil sands development

    International Nuclear Information System (INIS)

    Sugiura, T.

    1994-01-01

    According to Japanese national policy, exploration and development by Japanese companies in overseas countries are promoted in order to ensure stable oil supplies. Japan Canada Oil Sands Limited (JACOS), part of the JAPEX group, was established during the 1978 world oil crisis to explore and develop Canadian oil sand resources in accordance with Japan's national policy. The JAPEX group, including JACOS, has invested $123 million in oil sands projects in Alberta. JAPEX's first involvement in oil sands was in the Primrose Project operated by Norcen in the Cold Lake area. Five years of cyclic steam stimulation pilot tests did not produce sufficiently good results to justify further operation. The second involvement was the PCEJ Project, a joint effort by four companies that are participating in a bitumen recovery test project in the Athabasca Deposit. JACOS holds 2,452 km 2 of oil sands leases in Alberta. Tests conducted since 1978 in the PCEJ Project include multiwell steam injection pilot tests, some of which showed promise. JACOS is also participating in steam assisted gravity drainage projects and in federal/provincial research programs. Obstacles identified in developing Alberta oil sands are the lack of a bitumen pipeline to Edmonton and the insufficient length of oil sands leases (currently 10 years), given the difficulties of oil sand development. 10 figs

  2. Oil sands development update

    International Nuclear Information System (INIS)

    1999-01-01

    A detailed review and update of oil sands development in Alberta are provided covering every aspect of the production and economic aspects of the industry. It is pointed out that at present oil sands account for 28 per cent of Canadian crude oil production, expected to reach 50 per cent by 2005. Based on recent announcements, a total of 26 billion dollars worth of projects are in progress or planned; 20 billion dollars worth of this development is in the Athabasca area, the remainder in Cold Lake and other areas. The current update envisages up to 1,800,000 barrels per day by 2008, creating 47,000 new jobs and total government revenues through direct and indirect taxes of 118 billion dollars. Provinces other than Alberta also benefit from these development, since 60 per cent of all employment and income created by oil sands production is in other parts of Canada. Up to 60 per cent of the expansion is for goods and services and of this, 50 to 55 per cent will be purchased from Canadian sources. The remaining 40 per cent of the new investment is for engineering and construction of which 95 per cent is Canadian content. Aboriginal workforce by common consent of existing operators matches regional representation (about 13 per cent), and new developers are expected to match these standards. Planned or ongoing development in environmental protection through improved technologies and optimization, energy efficiency and improved tailings management, and active support of flexibility mechanisms such as emission credits trading, joint implementation and carbon sinks are very high on the industry's agenda. The importance of offsets are discussed extensively along with key considerations for international negotiations, as well as further research of other options such as sequestration, environmentally benign disposal of waste, and enhanced voluntary action

  3. Flow dynamics at the origin of thin clayey sand lacustrine turbidites: Examples from Lake Hazar, Turkey

    KAUST Repository

    Hage, Sophie

    2017-04-18

    Turbidity currents and their deposits can be investigated using several methods, i.e. direct monitoring, physical and numerical modelling, sediment cores and outcrops. The present study focuses on thin clayey sand turbidites found in Lake Hazar (Turkey) occurring in eleven clusters of closely spaced thin beds. Depositional processes and sources for three of those eleven clusters are studied at three coring sites. Bathymetrical data and seismic reflection profiles are used to understand the specific geomorphology of each site. X-ray, thin sections and CT-scans imagery combined with grain-size, geochemical and mineralogical measurements on the cores allow characterisation of the turbidites. Turbidites included in each cluster were produced by remobilization of surficial slope sediment, a process identified in very few studies worldwide. Three types of turbidites are distinguished and compared with deposits obtained in flume studies published in the literature. Type 1 is made of an ungraded clayey silt layer issued from a cohesive flow. Type 2 is composed of a partially graded clayey sand layer overlain by a mud cap, attributed to a transitional flow. Type 3 corresponds to a graded clayey sand layer overlain by a mud cap issued from a turbulence-dominated flow. While the published experimental studies show that turbulence is damped by cohesion for low clay content, type 3 deposits of this study show evidence for a turbulence dominated mechanism despite their high clay content. This divergence may in part relate to input variables such as water chemistry and clay mineralogy that are not routinely considered in experimental studies. Furthermore, the large sedimentological variety observed in the turbidites from one coring site to another is related to the evolution of a sediment flow within a field scale basin made of a complex physiography that cannot be tackled by flume experiments.

  4. Combined use of frequency‐domain electromagnetic and electrical resistivity surveys to delineate the freshwater/saltwater interface near saline lakes in the Nebraska Sand Hills, Nebraska, USA

    Science.gov (United States)

    Ong, John T.; White, Eric A.; Lane, John W.; Halihan, Todd; Zlotnik, Vitaly A; Butler, Dwain K.

    2009-01-01

    We investigate the use of frequency‐domain electromagnetic (FDEM) and electrical resistivity (ER) surveys for rapid and detailed characterization of the direction of lake‐aquifer fluxes and the configuration of salt plumes generated from saline lakes. This methodology was developed and applied at several lakes in the Nebraska Sand Hills, Nebraska, in an area with both freshwater and saline lakes hydraulically connected to the freshwater surficial aquifer. The FDEM survey was conducted by mounting the instrument on a fiberglass cart towed by an all‐terrain vehicle. The towed FDEM surveys covered about 25 km per day and served as a reconnaissance method for choosing locations for the more quantitative and detailed ER surveys. Around the saline lakes, areas with high electrical conductivity are consistent with the regional direction of ground‐water flow. Lower electrical conductivity was measured around the freshwater lakes with anomalies correlating to a paleovalley axis inferred from previous studies. The efficacy of this geophysical approach is attributed to: (1) significant contrast in electrical conductivity between freshwater and saltwater, (2) near‐surface location of the freshwater/saltwater interface, (3) minimal cultural interference, and (4) relative homogeneity of the aquifer materials.

  5. 76 FR 21637 - Safety Zone; Ford Estate Wedding Fireworks, Lake St. Clair, Grosse Pointe Shores, MI

    Science.gov (United States)

    2011-04-18

    ...-AA00 Safety Zone; Ford Estate Wedding Fireworks, Lake St. Clair, Grosse Pointe Shores, MI AGENCY: Coast... portion of Lake St. Clair River during the Ford Estate Wedding Fireworks. DATES: This rule is effective... vessels during the setup, loading, and launching of the Ford Estate Wedding Fireworks Display. The...

  6. A bright intra-dune feature on Titan and its implications for sand formation and transport

    Science.gov (United States)

    MacKenzie, Shannon; Barnes, Jason W.; Rodriguez, Sebastien; Cornet, Thomas; Brossier, Jeremy; Soderblom, Jason M.; Le Mouélic, Stephane; Sotin, Christophe; Brown, Robert H.; Buratti, Bonnie J.; Clark, Roger Nelson; Nicholson, Philip D.; Baines, Kevin

    2017-10-01

    Organic sands cover much of Titan’s equatorial belt, gathered into longitudinal dunes about a kilometer wide and hundreds of kilometers long. At the end of the Cassini era, questions of how such a vast volume of saltable material is or was created on Titan remain unanswered. At least two possible mechanisms suggested for forming sand-sized particles involve liquids: (1) evaporite deposition and erosion and (2) flocculation of material within a lake. Transporting sand from the lakes and seas of Titan’s poles to the equatorial belt is not strongly supported by Cassini observations: the equatorial belt sits higher than the poles and no sheets or corridors of travelling sand have been identified. Thus, previous sites of equatorial surface liquids may be of interest for understanding sand formation, such as the suggested paleoseas Tui and Hotei Regio. A newly identified feature in the VIMS data sits within the Fensal dune field but is distinct from the surrounding sand. We investigate this Bright Fensal Feature (BFF) using data from Cassini VIMS and RADAR. Specifically, we find spectral similarities between the BFF and both sand and Hotei Regio. The RADAR cross sectional backscatter is similar to neighboring dark areas, perhaps sand covered interdunes. We use this evidence to constrain the BFF’s formation history and discuss how this intra-dune feature may contribute to the processes of sand transport and supply.

  7. An investigation of several aspects of LANDSAT-5 data quality. [Palmer County, Shelby, mt; White sands, NM; Great Salt Lake, UT; San Matted Bridge and Sacramento, California

    Science.gov (United States)

    Wrigley, R. C. (Principal Investigator)

    1984-01-01

    Band-to-band registration, geodetic registration, interdector noise, and the modulation transfer function (MTE) are discussed for the Palmer County; TX scene. Band combinations for several LANDSAT 4 and LANDSAT 5 scenes; the geodetic registration test for the Sacramento, CA area; periodic noise components in TM band 5; and grey level measurements by detector for Great Salt Lake (UT) dark water forescans and backscans are considered. Results of MTF analyses of the San Mateo Bridge and of TM high resolution and aerial Daedalus scanner imagery are consistent and appear to be repeatable. An oil-on-sand target was constructed on the White Sands Missile Range in New Mexico. The two-image analysis procedure used is summarized.

  8. Evolutionary relationships in the sand-dwelling cichlid lineage of lake tanganyika suggest multiple colonization of rocky habitats and convergent origin of biparental mouthbrooding.

    Science.gov (United States)

    Koblmüller, Stephan; Salzburger, Walter; Sturmbauer, Christian

    2004-01-01

    The cichlid species flock of Lake Tanganyika is comprised of seven seeding lineages that evolved in step with changes of the lake environment. One seeding lineage diversified into at least six lineages within a short period of time. Our study focuses on the diversification of one of these lineages, the Ectodini, comprising highly specialized, sand- and rock-dwelling species. They display two distinct breeding styles: maternal and biparental mouthbrooding. By analyzing three mtDNA gene segments in 30 species representing all 13 described genera, we show that the Ectodini rapidly diversified into four clades at the onset of their radiation. The monotypic genus Grammatotria is likely to represent the most ancestral split, followed by the almost contemporary origin of three additional clades, the first comprising the benthic genus Callochromis, the second comprising the benthic genera Asprotilapia, Xenotilapia, Enantiopus, and Microdontochromis, and the third comprising the semi-pelagic genera Ophthalmotilapia, Cardiopharynx, Cyathopharynx, Ectodus, Aulonocranus, Lestradea, and Cunningtonia. Our study confirms the benthic and sand-dwelling life-style as ancestral. Rocky habitats were colonized independently in the Xenotilapia- and Ophthalmotilapia-clade. The Xenotilapia-clade comprises both maternal and biparental mouthbrooders. Their mode of breeding appears to be highly plastic: biparental mouthbrooding either evolved once in the common ancestor of the clade, to be reverted at least three times, or evolved at least five times independently from a maternally mouthbrooding ancestor. Furthermore, the genera Xenotilapia, Microdontochromis, Lestradea, and Ophthalmotilapia appeared paraphyletic in our analyses, suggesting the need of taxonomic revision.

  9. Reclaimability of the spent sand mixture – sand with bentonite – sand with furfuryl resin

    Directory of Open Access Journals (Sweden)

    J. Dańko

    2011-04-01

    Full Text Available Introduction of new binding materials and new technologies of their hardening in casting moulds and cores production requires theapplication of reclamation methods adequate to their properties as well as special devices realizing tasks. The spent sands circulationsystem containing the same kind of moulding and core sands is optimal from the point of view of the expected reclamation results.However, in the face of a significant variability of applied technologies and related to them various reclamation methods, the need - of theobtained reclamation products assessment on the grounds of systematic criteria and uniform bases – arises, with a tendency of indicatingwhich criteria are the most important for the given sand system. The reclaimability results of the mixture of the spent moulding sand withGeko S bentonite and the spent core sand with the Kaltharz 404U resin hardened by acidic hardener 100 T3, are presented in the paper.Investigations were performed with regard to the estimation of an influence of core sands additions (10 –25% on the reclaimed materialquality. Dusts and clay content in the reclaim, its chemical reaction (pH and ignition loss were estimated. The verification of the reclaiminstrumental assessment was performed on the basis of the technological properties estimation of moulding sand with bentonite, where the reclaimed material was used as a matrix.

  10. Dynamics of Nearshore Sand Bars and Infra-gravity Waves: The Optimal Theory Point of View

    Science.gov (United States)

    Bouchette, F.; Mohammadi, B.

    2016-12-01

    It is well known that the dynamics of near-shore sand bars are partly controlled by the features (location of nodes, amplitude, length, period) of the so-called infra-gravity waves. Reciprocally, changes in the location, size and shape of near-shore sand bars can control wave/wave interactions which in their turn alter the infra-gravity content of the near-shore wave energy spectrum. The coupling infra-gravity / near-shore bar is thus definitely two ways. Regarding numerical modelling, several approaches have already been considered to analyze such coupled dynamics. Most of them are based on the following strategy: 1) define an energy spectrum including infra-gravity, 2) tentatively compute the radiation stresses driven by this energy spectrum, 3) compute sediment transport and changes in the seabottom elevation including sand bars, 4) loop on the computation of infra-gravity taking into account the morphological changes. In this work, we consider an alternative approach named Nearshore Optimal Theory, which is a kind of breakdown point of view for the modeling of near-shore hydro-morphodynamics and wave/ wave/ seabottom interactions. Optimal theory applied to near-shore hydro-morphodynamics arose with the design of solid coastal defense structures by shape optimization methods, and is being now extended in order to model dynamics of any near-shore system combining waves and sand. The basics are the following: the near-shore system state is through a functional J representative of the energy of the system in some way. This J is computed from a model embedding the physics to be studied only (here hydrodynamics forced by simple infra-gravity). Then the paradigm is to say that the system will evolve so that the energy J tends to minimize. No really matter the complexity of wave propagation nor wave/bottom interactions. As soon as J embeds the physics to be explored, the method does not require a comprehensive modeling. Near-shore Optimal Theory has already given

  11. 77 FR 40515 - Safety Zone; Detroit Symphony Orchestra at Ford House Fireworks, Lake St. Clair, Grosse Pointe...

    Science.gov (United States)

    2012-07-10

    ...-AA00 Safety Zone; Detroit Symphony Orchestra at Ford House Fireworks, Lake St. Clair, Grosse Pointe... Detroit Symphony Orchestra at the Ford House Fireworks. This zone will be effective and enforced from 10.... 165.T09-0600 Safety Zone; Detroit Symphony Orchestra at Ford House Fireworks, Lake St. Clair, Grosse...

  12. Modeling erosion and accretion along the Illinois Lake Michigan shore using integrated airborne, waterborne and ground-based method

    Science.gov (United States)

    Mwakanyamale, K. E.; Brown, S.; Larson, T. H.; Theuerkauf, E.; Ntarlagiannis, D.; Phillips, A.; Anderson, A.

    2017-12-01

    Sediment distribution at the Illinois Lake Michigan shoreline is constantly changing in response to increased human activities and complex natural coastal processes associated with wave action, short and long term fluctuations in lake level, and the influence of coastal ice. Understanding changes to volume, distribution and thickness of sand along the shore through time, is essential for modeling shoreline changes and predicting changes due to extreme weather events and lake-level fluctuation. The use of helicopter transient electromagnetic (HTEM) method and integration with ground-based and waterborne geophysical and geologic methods provides high resolution spatial rich data required for modeling the extent of erosion and accretion at this dynamic coastal system. Analysis and interpretation of HTEM, ground and waterborne geophysical and geological data identify spatial distribution and thickness of beach and lake-bottom sand. The results provide information on existence of littoral sand deposits and identify coastal hazards such as lakebed down-cutting that occurs in sand-starved areas.

  13. A Improved Seabed Surface Sand Sampling Device

    Science.gov (United States)

    Luo, X.

    2017-12-01

    In marine geology research it is necessary to obtain a suf fcient quantity of seabed surface samples, while also en- suring that the samples are in their original state. Currently,there are a number of seabed surface sampling devices available, but we fnd it is very diffcult to obtain sand samples using these devices, particularly when dealing with fne sand. Machine-controlled seabed surface sampling devices are also available, but generally unable to dive into deeper regions of water. To obtain larger quantities of seabed surface sand samples in their original states, many researchers have tried to improve upon sampling devices,but these efforts have generally produced ambiguous results, in our opinion.To resolve this issue, we have designed an improved andhighly effective seabed surface sand sampling device that incorporates the strengths of a variety of sampling devices. It is capable of diving into deepwater to obtain fne sand samples and is also suited for use in streams, rivers, lakes and seas with varying levels of depth (up to 100 m). This device can be used for geological mapping, underwater prospecting, geological engineering and ecological, environmental studies in both marine and terrestrial waters.

  14. What caused the decline of China's largest freshwater lake? Attribution analysis on Poyang Lake water level variations in recent years

    Science.gov (United States)

    Ye, Xuchun; Xu, Chong-Yu; Zhang, Qi

    2017-04-01

    In recent years, dramatic decline of water level of the Poyang Lake, China's largest freshwater lake, has raised wide concerns about the water security and wetland ecosystem. This remarkable hydrological change coincided with several factors like the initial operation of the Three Gorges Dam (TGD) in 2003, the big change of lake bottom topography due to extensive sand mining in the lake since 2000, and also climate change and other human activities in the Yangtze River basin may add to this complexity. Questions raised to what extent that the lake hydrological changes is caused by climate change and/or human activities. In this study, quantitative assessment was conducted to clarify the magnitude and mechanism of specific influencing factors on recent lake decline (2003-2014), with reference to the period of 1980-1999. The attempts were achieved through the reconstruction of lake water level scenarios by the framework of neural network. Major result indicates that the effect of lake bottom topography change due to sand mining activities has became the dominant factor for the recent lake decline, especially in winter season with low water level. However, the effect of TGD regulation shows strong seasonal features, its effect can accounts for 33%-42% of the average water level decline across the lake during the impoundment period of September-October. In addition, the effect of climate change and other human activities over the Yangtze River basin needs to be highly addressed, which is particularly prominent on reducing lake water level during the summer flood season and autumn recession period. The result also revealed that due to different mechanism, the responses of the lake water level to the three influencing factors are not consistent and show great spatial and temporal differences.

  15. Monitoring mercury in freshwater fish in the oil sands region of Northern Alberta : spatial and temporal comparisons to regional mercury concentrations in fish

    International Nuclear Information System (INIS)

    Keith, H.

    2010-01-01

    The Regional Aquatics Monitoring Program (RAMP) was launched to provide a better understanding of the potential effects of oil sands development on aquatic systems, and to address issues important to communities of northern Alberta, such as mercury concentrations in fish. Muskeg dewatering, deforestation, flooding, and air emissions are among the potential mercury sources entering the aquatic systems within the oil sands region. RAMP collects non-lethal tissue samples on an annual basis for mercury analysis from northern pike (Esox lucius), walleye (Sander vitreus), and lake whitefish (Coregonus clupeaformis) in various rivers and lakes within the oil sands region. The purpose is to evaluate the suitability of fisheries resources for human consumption and to evaluate the potential cumulative biological effects on fish. A mercury database was developed based on studies in other regions in Alberta and across Canada in order to provide a regional context to the RAMP monitoring results. Data points from 1975 to 2009 were mapped to evaluate spatial and temporal differences in mercury concentrations and any exceedances of subsistence and general consumption guidelines. This monitoring effort has been instrumental in determining whether changes in mercury concentrations in fish are localized to a specific waterbody or regional in nature.

  16. Geotechnical properties of oil-contaminated Kuwaiti sand

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sanad, H.A.; Eid, W.K.; Ismael, N.F. [Kuwait Univ., Safat (Kuwait). Dept. of Civil Engineering

    1995-05-01

    Large quantities of oil-contaminated sands resulted from exploded oil wells, burning oil fires, the destruction of oil storage tanks, and the formation of oil lakes in Kuwait at the end of the Gulf War. An extensive laboratory testing program was carried out to determine the geotechnical characteristics of this material. Testing included basic properties, compaction and permeability tests, and triaxial and consolidation tests on clean and contaminated sand at the same relative density. Contaminated specimens were prepared by mixing the sand with oil in the amount of 6% by weight or less to match field conditions. The influence of the type of oil, and relative density was also investigated by direct shear tests. The results indicated a small reduction in strength and permeability and an increase in compressibility due to contamination. The preferred method of disposal of this material is to use it as a stabilizing material for other projects such as road construction.

  17. Geotechnical properties of oil-contaminated Kuwaiti sand

    International Nuclear Information System (INIS)

    Al-Sanad, H.A.; Eid, W.K.; Ismael, N.F.

    1995-01-01

    Large quantities of oil-contaminated sands resulted from exploded oil wells, burning oil fires, the destruction of oil storage tanks, and the formation of oil lakes in Kuwait at the end of the Gulf War. An extensive laboratory testing program was carried out to determine the geotechnical characteristics of this material. Testing included basic properties, compaction and permeability tests, and triaxial and consolidation tests on clean and contaminated sand at the same relative density. Contaminated specimens were prepared by mixing the sand with oil in the amount of 6% by weight or less to match field conditions. The influence of the type of oil, and relative density was also investigated by direct shear tests. The results indicated a small reduction in strength and permeability and an increase in compressibility due to contamination. The preferred method of disposal of this material is to use it as a stabilizing material for other projects such as road construction

  18. The Younger Dryas phase of Great Salt Lake, Utah, USA

    Science.gov (United States)

    Oviatt, Charles G.; Miller, D.M.; McGeehin, J.P.; Zachary, C.; Mahan, S.

    2005-01-01

    Field investigations at the Public Shooting Grounds (a wildlife-management area on the northeastern shore of Great Salt Lake) and radiocarbon dating show that the Great Salt Lake rose to the Gilbert shoreline sometime between 12.9 and 11.2 cal ka. We interpret a ripple-laminated sand unit exposed at the Public Shooting Grounds, and dated to this time interval, as the nearshore sediments of Great Salt Lake deposited during the formation of the Gilbert shoreline. The ripple-laminated sand is overlain by channel-fill deposits that overlap in age (11.9-11.2 cal ka) with the sand, and by wetland deposits (11.1 to 10.5 cal ka). Consistent accelerator mass spectrometry radiocarbon ages were obtained from samples of plant fragments, including those of emergent aquatic plants, but mollusk shells from spring and marsh deposits yielded anomalously old ages, probably because of a variable radiocarbon reservoir effect. The Bonneville basin was effectively wet during at least part of the Younger Dryas global-cooling interval, however, conflicting results from some Great Basin locations and proxy records indicate that the regional effects of Younger Dryas cooling are still not well understood. ?? 2005 Elsevier B.V. All rights reserved.

  19. The sediment accumulation rates measured in Lake Poyang using 210Pb dating method

    International Nuclear Information System (INIS)

    Wang Xiuyu; Zeng Erkang; Wan Yusong; Liu Xiaosong

    1987-01-01

    The sediment accumulation rates were estimated from the vertical distribution of excess 210 Pb measured in sediment cores collected from Lake Poyang, Jiangxi Provence of China. These rates were various with the differences in hydrology. The sedimentation rates are the lowest in the middle region of the lake, in which the rates could not be determined from the two samples and the other one is 0.14 cm/a. The sedimentation rates are lower in the northeast basin section, averaging to 0.19 cm/a. The sediment rates in the diffusion area of the lake from which 5 rivers enter sand deposion is more than the rates in other areas of the lake (0.08 cm/a to 0.28 cm/a) and the hydrology factors are various. Because of the sand from the Yangzhi River the sedimentation rates are the highest in the water-way section of the lake, averaging from 0.23 to 0.62 cm/a

  20. Spatial dispersion modeling of 90Sr by point cumulative semivariogram at Keban Dam Lake, Turkey

    International Nuclear Information System (INIS)

    Kuelahci, Fatih; Sen, Zekai

    2007-01-01

    Spatial analysis of 90 Sr artificial radionuclide in consequence of global fallout and Chernobyl nuclear accident has been carried out by using the point cumulative semivariogram (PCSV) technique based on 40 surface water station measurements in Keban Dam Lake during March, April, and May 2006. This technique is a convenient tool in obtaining the regional variability features around each sampling point, which yields the structural effects also in the vicinity of the same point. It presents the regional effect of all the other sites within the study area on the site concerned. In order to see to change of 90 Sr, the five models are constituted. Additionally, it provides a measure of cumulative similarity of the regional variable, 90 Sr, around any measurement site and hence it is possible to draw regional similarity maps at any desired distance around each station. In this paper, such similarity maps are also drawn for a set of distances. 90 Sr activities in lake that distance approximately 4.5 km from stations show the maximum similarity

  1. Surficial geologic map of the Red Rock Lakes area, southwest Montana

    Science.gov (United States)

    Pierce, Kenneth L.; Chesley-Preston, Tara L.; Sojda, Richard L.

    2014-01-01

    The Centennial Valley and Centennial Range continue to be formed by ongoing displacement on the Centennial fault. The dominant fault movement is downward, creating space in the valley for lakes and the deposition of sediment. The Centennial Valley originally drained to the northeast through a canyon now represented by a chain of lakes starting with Elk Lake. Subsequently, large landslides blocked and dammed the drainage, which created Lake Centennial, in the Centennial Valley. Sediments deposited in this late Pleistocene lake underlie much of the valley floor and rest on permeable sand and gravel deposited when the valley drained to the northeast. Cold Pleistocene climates enhanced colluvial supply of gravelly sediment to mountain streams and high peak flows carried gravelly sediment into the valley. There, the lower gradient of the streams resulted in deposition of alluvial fans peripheral to Lake Centennial as the lake lowered through time to the level of the two present lakes. Pleistocene glaciers formed in the high Centennial Range, built glacial moraines, and also supplied glacial outwash to the alluvial fans. Winds from the west and south blew sand to the northeast side of the valley building up high dunes. The central part of the map area is flat, sloping to the west by only 0.6 meters in 13 kilometers (2 feet in 8 miles) to form a watery lowland. This lowland contains Upper and Lower Red Rock Lakes, many ponds, and peat lands inside the “water plane,” above which are somewhat steeper slopes. The permeable sands and gravels beneath Lake Centennial sediments provide a path for groundwater recharged from the adjacent uplands. This groundwater leaks upward through Lake Centennial sediments and sustains wetland vegetation into late summer. Upper and Lower Red Rock Lakes are formed by alluvial-fan dams. Alluvial fans converge from both the south and the north to form outlet thresholds that dam the two shallow lakes upstream. The surficial geology aids in

  2. A preliminary study on sedimentation rate in Tasek Bera Lake estimated using Pb-210 dating technique

    International Nuclear Information System (INIS)

    Wan Zakaria Wan Muhamad Tahir; Johari Abdul Latif; Juhari Mohd Yusof; Kamaruzaman Mamat; Gharibreza, M.R.

    2010-01-01

    Tasek Bera is the largest natural lake system (60 ha) in Malaysia located in southwest Pahang. The lake is a complex dendritic system consisting of extensive peat-swamp forests. The catchment was originally lowland dipterocarp forest, but this has nearly over the past four decades been largely replaced with oil palm and rubber plantations developed by the Federal Land Development Authority (FELDA). Besides the environmentally importance of Tasek Bera, it is seriously subjected to erosion, sedimentation and morphological changes. Knowledge and information of accurate sedimentation rate and its causes are of utmost importance for appropriate management of lakes and future planning. In the present study, environmental 210 Pb (natural) dating technique was applied to determine sedimentation rate and pattern as well as the chronology of sediment deposit in Tasek Bera Lake. Three undisturbed core samples from different locations at the main entry and exit points of river mouth and in open water within the lake were collected during a field sampling campaign in October 2009 and analyzed for 210 Pb using gamma spectrometry method. Undisturbed sediments are classified as organic soils to peat with clayey texture that composed of 93 % clay, 5 % silt, and 2 % very fine sand. Comparatively higher sedimentation rates in the entry (0.06-1.58 cm/ yr) and exit (0.05-1.55 cm/ yr) points of the main river mouth as compared to the lakes open water (0.02- 0.74 cm/ yr) were noticed. Reasons for the different pattern of sedimentation rates in this lake and conclusion are discussed in this paper. (author)

  3. Technology unlocks tar sands energy

    Energy Technology Data Exchange (ETDEWEB)

    Law, C

    1967-09-25

    Tar sand processing technology has been developed primarily in the categories of extraction techniques and in-situ processing. In October, a $235 million venture into tar sand processing will be inspected by visitors from many points on the globe. A synthetic crude of premium quality will be flowing through a 16-in. pipeline from the Tar Island plant site of Great Canadian Oil Sands to Edmonton. This processing plant uses an extractive mining technique. The tar sand pay zone in this area averages approximately 150 ft in thickness with a 50-ft overburden. It has been estimated that the tar sands cannot be exploited when the formation thickness is less than 100 ft and overburden exceeds the same amount. This indicates that extraction techniques can only be used to recover approximately 15% of the tar sand deposits. An in-situ recovery technique developed by Shell of Canada is discussed in detail. In essence it is selective hydraulic fracturing, followed by the injection of emulsifying chemicals and steam.

  4. Fish gill responses to pollutants from oil sands mining-associated waters

    International Nuclear Information System (INIS)

    Lee, L.E.J.; Willfang, S.; Lamb, M.P.; Nero, V.; Farwell, A.J.; Dixon, D.G.

    2002-01-01

    The processing of Athabasca Deposit oil sands results in large amounts of liquid wastes associated with oil sand tailings. In addition to containing polycyclic aromatic hydrocarbons (PAHs), these waste waters are high in salinity and naphthenic acids which may be toxic to aquatic biota and their effects must be clarified. This study presents a suite of tests for in-depth and quick analysis of tailings water toxicity and contributes to the assessment of environmental risk. Yellow perch, fathead minnows, and rainbow trout were exposed to reclamation ponds where both in vivo and in vitro evaluation of crude and individual naphthenic acids and salts were conducted to examine their effect on fish gills which are very susceptible to contaminants. The fish exposed to the reclamation ponds showed higher incidence of gill pathological changes than control fish in Mildred Lake, a reservoir lake whose waters are diverted for use in oil sands extraction. Notable gill histopathological changes were observed when fish were exposed in vivo to sulfate/chloride salts and to abietic acid. Changes in membrane integrity, lysosomal activity and general morphology were observed when fished were exposed in vitro to salts, commercial napthenic acids or crude naphthenic extracts from the reclamation ponds

  5. Seasonal geomorphic processes and rates of sand movement at Mount Baldy dune in Indiana, USA

    Science.gov (United States)

    Kilibarda, Zoran; Kilibarda, Vesna

    2016-12-01

    Winds are very strong, frequent, and have high energy (annual DP ∼800 VU) along the southern shores of Lake Michigan, allowing the coexistence of fixed and active dunes. Six years (2007-13) of monitoring Mount Baldy in the Indiana Dunes National Lakeshore reveals that this is the most active coastal dune in the Great Lakes region. This paper documents aeolian processes and changes in the dune's morphology that occur temporarily, following storms, or seasonally, due to weather (climate) variations. Most of the sand transport in this area takes place during strong storms with gale force (>17.5 m/s) winds, which occur in the autumn and winter months. A single storm, such as the October 28-31, 2013 event, can contribute 25% of the annual sand transport and dune movement inland. In its most active year (June 1, 2011 through May 31, 2012), Mount Baldy moved inland on average 4.34 m, with a maximum of 6.52 m along the blowout's axis (155° azimuth). During this particularly active season, there were six storms with sustained gale force winds, winter air temperatures were warmer than average, and shelf ice on Lake Michigan lasted only one day. The dune is least active during the summer season, when the winds are weakest. The late fall and winter winds are the strongest. But in a typical year, most of the dune's advance inland takes place during the spring thaw when sand is released from over-steepened and lumpy slip face, allowing it to avalanche to the toe of the slip face. However, with a warming air temperatures, a reduction in the duration of winter shelf ice, and rising Lake Michigan levels, the annual rates of sand transport and dune movement may increase. The recent Mount Baldy management strategy, which includes planting vegetation and installing wind barriers on the dune's stoss side in an effort to fix the dune and stop its further movement inland, may potentially cause the destruction of the mobile sand, open dune habitat, resulting in the extinction of rare

  6. Preliminary fingerprinting analysis of Alberta oil sands and related petroleum products

    International Nuclear Information System (INIS)

    Yang, C.; Wang, Z.D.; Hollebone, B.; Brown, C.E.; Yang, Z.Y.; Landriault, M.; Fieldhouse, B.

    2009-01-01

    This paper reported on a study that presented a preliminary quantitative chemical characterization of Alberta oil sands and many other related Alberta oils such as oil sand bitumen, Cold Lake bitumen, Albian heavy synthetic crude, and Alberta Mixed sweet blend. The rapid increase in production of the Alberta oil sands has resulted in unprecedented environmental concern. The mining, extraction and production of oil sands such resulted in huge consumption of water resources, huge emission of greenhouse gas and large number of tailings ponds. In addition, accidental spills in the transportation and usage of oil sands will potentially cause considerable impact on the environment. It is therefore essential to have the ability to characterize Alberta oil sands and their oil products. The specific chemical properties of the oil sands bitumen must be known. Therefore, this study collected quantitative data on the concentration and distribution profiles of target compounds in Alberta oil sands and its petroleum products. The chemical fingerprints of 5 Alberta oil sands and their related petroleum products were studied using gas chromatography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS). The characterized hydrocarbons were n-alkanes; target alkylated PAHs and other EPA priority PAHs; biomarker terpanes and steranes; and bicyclic sesquiterpanes. The information acquired during this study will provide the basis for oil-oil correlation and differentiation in future environmental applications relevant to oil sands. 24 refs., 6 tabs., 4 figs.

  7. An introduction to conservation and reclamation at Alberta's mineable oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Richens, T. [Alberta Environment, Edmonton, AB (Canada)

    2009-07-01

    This paper presented a balanced view of the conservation and reclamation issues and challenges facing oil sands development in Alberta. Bitumen is recovered by truck and shovel in the shallow oil sands of the Athabasca region. The deeper deposits in the Athabasca, Peace River and Cold Lake regions are accessed primarily using a system of horizontal wells and steam to extract the bitumen from the sand and pump it to the surface. Individual in-situ operations have a smaller environmental impact than mines, and do not produce tailings ponds. However, the footprint of in-situ facilities will accumulate over time because of the potential for extensive future development. The key issues facing conservation and reclamation in the mineable oil sands were discussed. Summary statistics on land disturbed and reclaimed in the region were also provided. The challenges facing reclamation activities include long timeframes; large scale, regional planning and integration; competing land use goals; revegetation; byproduct management; and tailings and process-affected water. Multi-stakeholder forums have proven to be the key to the progression of monitoring, research and development and the sharing of knowledge and information. Frameworks have been developed for the assessment of pre-disturbed and reclaimed soil capability specific to the oil sands region. Additional resources are also available, such as guidelines for the reclamation of terrestrial and wetland habitats that represent the best management practices for reclamation research in revegetation, soil salvage, stockpiling and placement, tailings reclamation, end pit lakes, wetlands and biodiversity. 16 refs., 1 fig.

  8. Heavy Metal Contamination in the Surface Layer of Bottom Sediments in a Flow-Through Lake: A Case Study of Lake Symsar in Northern Poland

    Directory of Open Access Journals (Sweden)

    Angela Kuriata-Potasznik

    2016-08-01

    Full Text Available River-lake systems most often behave as hydrographic units, which undergo complex interactions, especially in the contact zone. One such interaction pertains to the role of a river in the dispersal of trace elements carried into and out of a lake. In this study, we aimed to assess the impact of rivers on the accumulation of heavy metals in bottom sediments of natural lakes comprised in postglacial river-lake systems. The results showed that a river flowing through a lake is a key factor responsible for the input of the majority of available fraction of heavy metals (Zn, Mn, Cd and Ni into the water body and for their accumulation along the flow of river water in the lake. The origin of other accumulated elements were the linear and point sources in catchments. In turn, the Pb content was associated with the location of roads in the direct catchment, while the sediment structure (especially size of fraction and density could have affected the accumulation of Cr and Zn, which indicated correlations between these metals and fine fraction. Our results suggest that lakes act as filters and contribute to the self-purification of water that flows through them. As a result, the content of most metals in lake sediments showed a decrease by approx. 75% between the upstream (inflow and downstream (outflow sections. The increased content of two metals only, such as chromium and cadmium (higher by 2.0 and 2.5 times, respectively, after passing through the lake, was due to the correlation of the metals with fine sand. Both the content and distribution pattern of heavy metals in lake sediments are indicative of the natural response of aquatic ecosystems to environmental stressors, such as pollutant import with river water or climate change. The complex elements creating the water ecosystem of each lake can counteract stress by temporarily removing pollutants such as toxic metals form circulation and depositing them mostly around the delta.

  9. Occurrence of Escherichia coli and Enterococci in Cladophora (Chlorophyta) in Nearshore Water and Beach Sand of Lake Michigan†

    Science.gov (United States)

    Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith B.; Byappanahalli, Muruleedhara N.

    2003-01-01

    Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (± standard errors) of 5.3 (± 4.8) and 4.8 (± 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P Cladophora mats stored at 4°C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches. PMID:12902262

  10. Occurrence of Escherichia coli and enterococci in Cladophora (Chlorophyta) in nearshore water and beach sand of Lake Michigan.

    Science.gov (United States)

    Whitman, Richard L; Shively, Dawn A; Pawlik, Heather; Nevers, Meredith B; Byappanahalli, Muruleedhara N

    2003-08-01

    Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (+/- standard errors) of 5.3 (+/- 4.8) and 4.8 (+/- 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P Cladophora mats stored at 4 degrees C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches.

  11. 76 FR 55564 - Safety Zone; Revolution 3 Triathlon, Sandusky Bay, Lake Erie, Cedar Point, OH

    Science.gov (United States)

    2011-09-08

    ...-AA00 Safety Zone; Revolution 3 Triathlon, Sandusky Bay, Lake Erie, Cedar Point, OH AGENCY: Coast Guard... Erie during the Revolution 3 Triathlon. This temporary safety zone is necessary to protect participants..., between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. FOR FURTHER INFORMATION CONTACT...

  12. Sand (CSW4)

    CSIR Research Space (South Africa)

    Estuarine and Coastal Research Unit

    1982-12-01

    Full Text Available This report is one of a series on Cape Estuaries being published under the general title "The Estuaries of the Cape, Part 2". The report provides information on sand estuary: historical background, abiotic and biotic characteristics. It is pointed...

  13. Occurrence of Escherichia coli and Enterococci in Cladophora (Chlorophyta) in Nearshore Water and Beach Sand of Lake Michigan†

    OpenAIRE

    Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith B.; Byappanahalli, Muruleedhara N.

    2003-01-01

    Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation...

  14. Occurrence of parasites of the genus Eustrongylides spp. (Nematoda: Dioctophymatidae in fish caught in Trasimeno lake, Italy

    Directory of Open Access Journals (Sweden)

    Raffaella Branciari

    2016-11-01

    Full Text Available Eustrongylides spp. is considered a freshwater fish zoonotic nematode. In the present study, the prevalence of Eustrongylides spp. in six edible fish (European perch - Perca fluviatilis, goldfish - Carassius auratus, largemouth black bass - Micropterus salmoides, tench- Tinca tinca, carp - Cyprinus carpio and sand smelt - Atherina boyeri of Trasimeno lake was surveyed. The investigations were conducted from October 2014 to September 2015 and 384 specimens per species for each season were caught in Trasimeno lake and examined for the presence of larvae in the abdominal cavity and muscle. The presence of nematodes in the abdominal cavity and musculature was revealed in three fish species. The prevalence of Eustrongylides spp. infection was 6.84, 1.89 and 0.13% in perch, largemouth black bass and sand smelt, respectively. The number of parasites per fish was only one in largemouth black bass and sand smelt and ranged from one up to three in perch. This study states that the European perch, largemouth black bass and sand smelt of Trasimeno lake are infected with zoonotic parasites; therefore, food business operators have to take appropriate measures to guarantee the health of consumers.

  15. Preliminary fiscal evaluation of Alberta oil sands terms

    International Nuclear Information System (INIS)

    Van Meurs, P.

    2007-01-01

    The cost of oil sands projects varies significantly. While costs have escalated considerably over the past few years, oil prices have gone significantly higher. This report provided an economic evaluation of the current fiscal terms applicable to Alberta oil sands. The analysis was done to evaluate the profitability of oil sand projects to investors under current conditions based on the generic royalty regime based on bitumen values. The objective of the royalty review was to determine whether Albertans received a fair share from their oil and gas resources. It discussed the wide variety of oil sands projects in Alberta using five case studies as examples. Cases involving steam assisted gravity drainage (SAGD) operations were assessed for both the Athabasca Mine and Cold Lake. The report provided a discussion of the economic assumptions including economic cases as well as production, costs and price data. It then provided the preliminary results of the economic-fiscal evaluation from the investor perspective including profitability indicators; international comparisons; internal rate of return; and net present value. The government perspective was also discussed with reference to attractiveness indicators; royalties as a percentage of bitumen values; and non-discounted and discounted government take. A royalty and tax feature analysis was also provided. Several issues for possible further review were also presented. tabs

  16. Modeling potential impacts of the Garrison Diversion Unit project on Sand Lake and Arrowwood National Wildlife Refuges: a feasibility analysis

    Science.gov (United States)

    Hamilton, David B.; Auble, Gregor T.; Farmer, Adrian H.; Roelle, James E.

    1987-01-01

    The Garrison Diversion Unit (GDU) of the Pick-Sloan Missouri Basin program was authorized in 1965, with the purpose of diverting Missouri River water to the James River for irrigation, municipal and industrial water supply, fish and wildlife habitat, recreation, and flood control. The project was reauthorized in 1986, with the specification that comprehensive studies be conducted to address a variety of issues. One of these ongoing studies addresses potential impacts of GDU construction and operation on lands of the National Wildlife Refuge (NWR) system, including Arrowwood and Sand Lake Refuges (the Refuges) on the James River. A number of concerns at these Refuges have been identified; the primary concerns addressed in this report include increased winter return flows, which would limit control of rough fish; increased turbidity during project construction, which would decrease production of sago pondweed; and increased water level fluctuations in the late spring and early summer, which would destroy the nests of some over-water nesting birds. The facilitated workshop described in this report was conducted February 18-20, 1987, under the joint sponsorship of the U.S. Bureau of Reclamation, the U.S. Fish and Wildlife Service, and the North Dakota Game and Fish Department. The primary objectives of the workshop were to evaluate the feasibility of using simulation modeling techniques to estimate GDU impacts on Arrowwood and Sand Lake Refuges and to suggest enhancements to the James River Refuge monitoring program. The workshop was structured around the formulation of four submodels: a Hydrology and Water Quality submodel to simulate changes in Refuge pool elevations, turnover rates, and water quality parameters (e.g., total dissolved solids, turbidity, dissolved oxygen, nutrients, water temperature, pesticides) due to GDU construction and operation; a Vegetation submodel to simulate concomitant changes in wetland communities (e.g., sago pondweed, wet meadows, deep

  17. Occurrence of Escherichia coli and enterococci in Cladophora (Clorophyta) in nearshore water and beach sand of Lake Michigan

    Science.gov (United States)

    Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith B.; Byappanahalli, Muruleedhara N.

    2003-01-01

    Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (± standard errors) of 5.3 (± 4.8) and 4.8 (± 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P R2 = 0.73, n = 17) but not in northern beaches (P = 0.892, n = 16). Both E. coli and enterococci survived for over 6 months in sun-dried Cladophora mats stored at 4°C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches.

  18. Influence green sand system by core sand additions

    Directory of Open Access Journals (Sweden)

    N. Špirutová

    2012-01-01

    Full Text Available Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: “How the green sand systems are influenced by core sands?”This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50 %. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition. Ratio of active betonite by Methylene blue test was also determined.

  19. A long record of extreme wave events in coastal Lake Hamana, Japan

    Science.gov (United States)

    Boes, Evelien; Yokoyama, Yusuke; Schmidt, Sabine; Riedesel, Svenja; Fujiwara, Osamu; Nakamura, Atsunori; Garrett, Ed; Heyvaert, Vanessa; Brückner, Helmut; De Batist, Marc

    2017-04-01

    Coastal Lake Hamana is located near the convergent tectonic boundary of the Nankai-Suruga Trough, along which the Philippine Sea slab is subducted underneath the Eurasian Plate, giving rise to repeated tsunamigenic megathrust earthquakes (Mw ≥ 8). A good understanding of the earthquake- and tsunami-triggering mechanisms is crucial in order to better estimate the complexity of seismic risks. Thanks to its accommodation space, Lake Hamana may represent a good archive for past events, such as tsunamis and tropical storms (typhoons), also referred to as "extreme wave" events. Characteristic event layers, consisting of sediment entrained by these extreme waves and their backwash, are witnesses of past marine incursions. By applying a broad range of surveying methods (reflection-seismic profiling, gravity coring, piston coring), sedimentological analyses (CT-scanning, XRF-scanning, multi-sensor core logging, grain size, microfossils etc.) and dating techniques (210Pb/137Cs, 14C, OSL, tephrochronology), we attempt to trace extreme wave event deposits in a multiproxy approach. Seismic imagery shows a vertical stacking of stronger reflectors, interpreted to be coarser-grained sheets deposited by highly energetic waves. Systematic sampling of lake bottom sediments along a transect from ocean-proximal to ocean-distal sites enables us to evaluate vertical and lateral changes in stratigraphy. Ocean-proximal, we observe a sequence of eight sandy units separated by silty background sediments, up to a depth of 8 m into the lake bottom. These sand layers quickly thin out and become finer-grained land-inward. Seismic-to-core correlations show a good fit between the occurrence of strong reflectors and sandy deposits, hence confirming presumptions based on acoustic imagery alone. Sand-rich intervals typically display a higher magnetic susceptibility, density and stronger X-ray attenuation. However, based on textural and structural differences, we can make the distinction between

  20. Role of rural solid waste management in non-point source pollution control of Dianchi Lake catchments, China

    Institute of Scientific and Technical Information of China (English)

    Wenjing LU; Hongtao WANG

    2008-01-01

    In recent years, with control of the main municipal and industrial point pollution sources and implementation of cleaning for some inner pollution sources in the water body, the discharge of point source pollution decreased gradually, while non-point source pollution has become increasingly distressing in Dianchi Lake catchments. As one of the major targets in non-point source pollution control, an integrated solid waste controlling strategy combined with a technological solution and management system was proposed and implemented based on the waste disposal situation and characteristics of rural solid waste in the demonstration area. As the key technoogy in rural solid waste treatment, both centralized plantscale composting and a dispersed farmer-operated waste treating system showed promise in rendering timely benefits in efficiency, large handling capacity, high quality of the end product, as well as good economic return. Problems encountered during multi-substrates co-com-posting such as pathogens, high moisture content, asyn-chronism in the decomposition of different substrates, and low quality of the end product can all be tackled. 92.5% of solid waste was collected in the demonstration area, while the treating and recycling ratio reached 87.9%, which pre-vented 32.2 t nitrogen and 3.9 t phosphorus per year from entering the water body of Dianchi Lake after imple-mentation of the project.

  1. Recently surveyed lakes in northern Manitoba and Saskatchewan, Canada: characteristics and critical loads of acidity

    Directory of Open Access Journals (Sweden)

    Isaac WONG

    2010-08-01

    Full Text Available Based on minimal information, lakes in the western Canadian provinces of Manitoba (MB and Saskatchewan (SK have long been considered unaffected by acid rain. However, emissions of acidifying pollutants from MB smelters and oil sand processing in Alberta (AB may pose a developing threat. Surveys of 347 lakes located on geologically sensitive terrain in northern MB and SK were conducted to assess their acidification sensitivity and status. The survey domain (~193,000 km2 contained 81,494 lakes ≥1 ha in area. Small lakes dominated the inventory in terms of numbers, and large lakes dominated in terms of area. Survey lakes were selected using a stratified-random sampling design in 10 sampling blocks within the overall survey domain. Few lakes had pH <6, and only three (all in SK were acidic, i.e., Gran Alkalinity (Alk <0 μeq L–1. A broad range in lake sensitivity was apparent, and very sensitive lakes (low specific conductance, base cations and Alk were present in all sampling blocks. Dissolved organic carbon (DOC was an important constituent of many lakes. Critical loads (CL of acidity calculated using the Steady-State Water Chemistry model (SSWC revealed extremely low 5th percentile values for every block (range 1.9 to 52.7 eq ha–1 y–1. Block CL exceedances calculated using estimated S and N deposition for 2002 ranged from 54.5 to 909 eq ha–1 y–1. The largest exceedances were for sampling blocks located near smelter sources or downwind of the oil sands. Lake chemistry revealed by our surveys was compared to others conducted both nearby and outside Canada.

  2. A mathematical model for lake ontogeny in terms of filling with sediments and macrophyte vegetation

    International Nuclear Information System (INIS)

    Brydsten, Lars

    2004-05-01

    A mathematical model for simulation of lake basin filling processes in areas with positive shore displacement was constructed. The model was calibrated using sediment and catchments data from eight existing lake basins situated in the northern coastal area of the province of Uppland, Sweden. The lake basin filling processes were separated into three phases: basin filling with wave-washed material (silt, silty sand or sand), filling with fine-grained material during the shallow gulf and lake stages, respectively, and filling with vegetation during the lake stage. The basin filling rates for wave-washed material were generally low but varied considerably both between and within lakes. The mean basin filling rate of wave-washed material was 4.1%. The volume of inorganic sediments produced, and basin filling rates during the shallow gulf and lake phases were determined for all the eight lakes. The relationship between basin filling rate and parameters describing the catchments, the former postglacial basins and the lakes, respectively, was determined using multiple regression analysis. The basin filling rate with inorganic sediments was best described by parameters related to former postglacial basin morphometry and current lake morphometry, e.g. basin volume, lake volume, and lake area. The goodness of fit turned out to be 0.99 for a simple regression with basin volume as the sole independent variable. The basin filling with vegetation (Phragmites australis followed by Sphagnum spp.) was treated as a 2-dimensional process. A dataset with 84 bogs was selected from a digital soil map. The ages of the bogs were calculated using a digital elevation map and an equation for shore displacement. The choke-up rate was then calculated by dividing the area of the bogs with their age. A strong exponential relationship exists between areas of the bogs and choke-up rat, and this relationship was then used in the model. The resulting model starts by filling the former coastal basin

  3. A mathematical model for lake ontogeny in terms of filling with sediments and macrophyte vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Brydsten, Lars [Umeaa Univ. (Sweden). Dept. of Biology and Environmental Science

    2004-05-01

    A mathematical model for simulation of lake basin filling processes in areas with positive shore displacement was constructed. The model was calibrated using sediment and catchments data from eight existing lake basins situated in the northern coastal area of the province of Uppland, Sweden. The lake basin filling processes were separated into three phases: basin filling with wave-washed material (silt, silty sand or sand), filling with fine-grained material during the shallow gulf and lake stages, respectively, and filling with vegetation during the lake stage. The basin filling rates for wave-washed material were generally low but varied considerably both between and within lakes. The mean basin filling rate of wave-washed material was 4.1%. The volume of inorganic sediments produced, and basin filling rates during the shallow gulf and lake phases were determined for all the eight lakes. The relationship between basin filling rate and parameters describing the catchments, the former postglacial basins and the lakes, respectively, was determined using multiple regression analysis. The basin filling rate with inorganic sediments was best described by parameters related to former postglacial basin morphometry and current lake morphometry, e.g. basin volume, lake volume, and lake area. The goodness of fit turned out to be 0.99 for a simple regression with basin volume as the sole independent variable. The basin filling with vegetation (Phragmites australis followed by Sphagnum spp.) was treated as a 2-dimensional process. A dataset with 84 bogs was selected from a digital soil map. The ages of the bogs were calculated using a digital elevation map and an equation for shore displacement. The choke-up rate was then calculated by dividing the area of the bogs with their age. A strong exponential relationship exists between areas of the bogs and choke-up rat, and this relationship was then used in the model. The resulting model starts by filling the former coastal basin

  4. Glacial Lake Pickering: stratigraphy and chronology of a proglacial lake dammed by the North Sea Lobe of the British-Irish Ice Sheet

    OpenAIRE

    Evans, David J.A.; Bateman, Mark D.; Roberts, David H.; Medialdea, Alicia; Hayes, Laura; Duller, Geoff A.T.; Fabel, Derek; Clark, Chris D.

    2016-01-01

    We report the first chronology, using four new optically stimulated luminescence dates, on the sedimentary record of Glacial Lake Pickering, dammed by the North Sea Lobe of the British–Irish Ice Sheet during the Dimlington Stadial (24–11 ka cal BP). Dates range from 17.6 ± 1.0 to 15.8 ± 0.9 ka for the sedimentation of the Sherburn Sands at East Heslerton, which were formed by multiple coalescing alluvial fans prograding into the falling water levels of the lake and fed by progressively larger...

  5. THE SOMEŞAN PLATEAU LAKES: GENESIS, EVOLUTION AND TERRITORIAL REPARTITION

    Directory of Open Access Journals (Sweden)

    Victor SOROCOVSCHI

    2010-06-01

    Full Text Available The present paper analyzes the genesis of the lake depressions in the Someşan Plateau and the way they evolved in time and space, as well as the morphometric elements characteristic of the different genetic types of lakes. The natural lakes in this region are few and their dimensions are small; they generally appear solitarily and only rarely as lake complexes. In this category have been included the valley lakes, the lakes formed in abandoned meanders and the lakes formed in areas with landslides. The artificial lakes are more numerous and include several genetic types. The most representative are the remnant lakes formed in the depressions resulted from the exploitation of different construction materials (kaolin sands, lime stones and the anthropic salty lakes lakes formed in abandoned salt mines from the diapir area of the Hills of Dej. The rapid evolution of these types of lakes has been highlighted through the comparative analysis of the morphometric elements obtained on the basis of topometric and bathymetric measurements. The lakes arranged for pisciculture include several subtypes (ponds, fish ponds that have been identified and characterized for the fist time, their morphometric elements being determined using digital data bases, satellite images and detailed topometric maps.

  6. Ground-water availability in the eastern part of the Lake Ontario Basin, New York

    Science.gov (United States)

    Miller, Todd S.

    1986-01-01

    A set of three maps show surficial geology, significant unconsolidated aquifers and well yield, and selected well locations for the Lake Ontario basin, New York. In the low areas , glaciers and wave action of former high-level lakes deposited permeable sand and gravel to form aquifers that yield more than 10 gal/min of water to wells. Small quantities of water (less than 2 gal/min) can be pumped from dug wells that top till and fine lake-sediment deposits. (USGS)

  7. Assessment of whether upstream passage for Lake Sturgeon is needed at the Pointe du Bois Generating Station (Winnipeg River)

    International Nuclear Information System (INIS)

    Pratt, T.

    2010-01-01

    This document reviewed Manitoba Hydro's proposal to modernize the Pointe du Bois Generating Station (GS) on the Winnipeg River, with particular reference to the potential impacts on Lake Sturgeon in Management Unit 5 (MU5) where large numbers of the fish spawn at the base of the falls. The modernization will involve replacing the spillway, dam segments and replacing or repairing the powerhouse. The pros and cons of providing upstream fish passage for Lake Sturgeon and the generating station were outlined. The only spawning area in the MU5 area may be altered considerably due to changes in water flow, depending on the design chosen for modernization. A potential benefit of providing upstream fish passage for Lake Sturgeon would be to increase genetic diversity within the Winnipeg River. Another potential benefit would be to allow Lake Sturgeon, from the relatively dense population below the GS, to move upstream into MU4 where unfilled habitat may be available and Lake Sturgeon abundance is lower. A potential disadvantage of providing fish passage would be the loss of individual Lake Sturgeon from the healthy population in MU5 with no accompanying benefit to MU4. There would be no net gain to MU4 or MU5 if migrating Lake Sturgeon returned to MU5 rather than proceeding upstream. It was concluded that these current gaps in knowledge must be filled in order to fully assess the environmental impacts. 2 figs.

  8. Development tendencies of moulding and core sands

    Directory of Open Access Journals (Sweden)

    Stanislaw M. Dobosz1

    2011-11-01

    Full Text Available Further development of the technology for making moulding and core sands will be strictly limited by tough requirements due to protection of the natural environment. These tendencies are becoming more and more tense, so that we will reach a point when even processes, that from technological point of view fulfill high requirements of the foundry industry, must be replaced by more ecologically-friendly solutions. Hence, technologies using synthetic resins as binding materials will be limited. This paper presents some predictable development tendencies of moulding and core sands. The increasing role of inorganic substances will be noticed, including silicate binders with significantly improved properties, such as improved knock-out property or higher reclamation strength. Other interesting solutions might also be moulding sands bonded by geo-polymers and phosphate binders or salts and also binders based on degradable biopolymers. These tendencies and the usefulness of these binders are put forward in this paper.

  9. Spatial distribution of nearshore fish in the vicinity of two thermal generating stations, Nanticoke and Douglas Point, on the Great Lakes

    International Nuclear Information System (INIS)

    Minns, C.K.; Kelso, J.R.M.; Hyatt, W.

    1978-01-01

    At Nanticoke, Lake Erie, 1974, mean fish density varied considerably, range 162-14 204/10 000 m 3 , as estimated by digital acoustic fish enumeration. At Douglas Point, Lake Huron, 1975, mean density varied less, range 108-671/10 000 m 3 . At both sites fish densities were generally greatest in the shallowest, 3-5 m, depths. At Nanticoke, where the nearshore has low relief, there were no distinguishable communities. At Douglas Point, where depth increases rapidly offshore, there was evidence of benthic and pelagic communities. There was no evidence of altered fish distribution in relation to temperature. At Nanticoke there was no vertical variation in temperature and no vertical response was to be expected. At Douglas Point there was thermal stratification present in the summer and there was no apparent response. The influence of incident radiation was uncertain because of the effects of diurnal migrations. At both locations fish were clustered horizontally to varying degrees in the spring and fall, while in the summer fish were distributed more evenly. Densest clusters were usually in the vicinity of the turbulent discharge at both locations. The lack of temperature response and the similarity of Nanticoke with situations at nearby streams on Lake Erie suggest that the fish are responding to currents and perhaps topography. (author)

  10. Pleistocene lake level changes in Western Mongolia

    Science.gov (United States)

    Borodavko, P. S.

    2009-04-01

    Global cooling in the Early Pleistocene caused extensive continental glaciation in the northern hemisphere including the arid areas of Central Asia. The reduction of temperatures (particularly summer temperatures) reduced evaporation and strengthened the importance of precipitation. The simultaneity of "lakes periods" (pluvials) and stages of glaciation is established experience confirmed by investigations in the west of North America and Russia. In the Mongolian Great Lakes Depression new evidence for similar conditions is found. The Great Lakes Depression is one of the largest in Central Asia, and is divided into 2 main Lakes basins: Hyargas Lake Basin and Uvs Lake Basin. The basin is 600-650 km in length with a width of 200-250 km in the north and 60-100 km in the south. Total catchment area is about 186600 km2. The elevation of the basin floor is from 1700 m a.s.l. to 760 m a.s.l., decreasing to the north and south-east. The depression extends south-north and is bounded by mountains: Tannu-Ola to the north, Hangai to the east; Gobi Altai to the south and Mongolian Altay to the west. The maximum elevation of the mountains is 4000 m a.s.l. There are some mountains with an elevation between 2000 and 3000 m a.s.l in the lake catchment. These mountains are not glaciated today. The geological record [1] suggests the Great Lakes Depression already existed in the Mesozoic, but assumed its modern form only during the Pliocene-Quaternary when tectonic movements caused the uplift of the surrounding mountains. A phase of tectonic stability occurred during the Late Quaternary. The depression is filled by Quaternary fluvial, aeolian and lacustrine deposits (e.g. sand, pebbles). The Neogene deposits are represented by coloured clay, marl, sand and sandstone [1]. Hyargas Lake is the end base level of erosion of the lake group consisting of the Hara-Us Nur, Dorgon, Hara Nur and Airag lakes. Hyargas is one of the largest lakes in Mongolia, with a water surface of 1,407 km2. The

  11. Analysis of point source pollution and water environmental quality variation trends in the Nansi Lake basin from 2002 to 2012.

    Science.gov (United States)

    Wang, Weiliang; Liu, Xiaohui; Wang, Yufan; Guo, Xiaochun; Lu, Shaoyong

    2016-03-01

    Based on the data analysis of the water environmental quality and economic development from 2002 to 2012 in the Nansi Lake basin, the correlation and change between the water environmental quality and economic development were studied. Results showed that the GDP and wastewater emissions of point source in the Nansi Lake basin had an average annual growth of 7.30 and 7.68 %, respectively, from 2002 to 2012. The emissions of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) had the average annual decrease of 7.69 and 6.79 % in 2012, respectively, compared to 2002. Basin water quality overall improved, reaching the Class III of the "Environmental quality standards for surface water (GB3838-2002)," in which the main reason was that sewage treatment rate increased gradually and was above 90 % in 2012 (an increase of 10 % compared to 2002) with the progress of pollution abatement technology and the implementation of relevant policies and regulations. The contribution of water environmental pollution was analyzed from related cities (Ji'ning, Zaozhuang, Heze). Results indicated that Ji'ning had the largest contribution to water pollution of the Nansi Lake basin, and the pollutant from domestic sources accounted for a higher percentage compared to industrial sources. The wastewater, COD, and NH3-N mainly came from mining and washing of coal, manufacture of raw chemical materials and chemical products, papermaking industry, and food processing industry. According to the water pollution characteristics of the Nansi Lake basin, the basin pollution treatment strategy and prevention and treatment system were dissected to provide a scientific basis for prevention and control of lakeside point source pollution along the Nansi Lake.

  12. Modelling of soil depth and lake sediments. An application of the GeoEditor at the Forsmark site

    International Nuclear Information System (INIS)

    Vikstroem, Maria

    2005-02-01

    This report aims at describing the modelled soil depth according to three layers with different hydrogeological properties at the Forsmark site, based on available data from boreholes, observation points, seismic data and radar profiles. For the lakes in the area, the sediment has been modelled according to six layers of the most common deposits in the area. The peat layer at Stenroesmossen has also been visualized. The program used in the modelling of soil depths is the GeoEditor, which is an ArcView3.3-extension. The input data used in the model consist of 1,532 points based on seismic measurements, 31 profiles of interpreted ground penetrating radar data, 119 boreholes and 472 observation points. The western and south eastern part of the area has a low data density. In the southern parts the data density with respect to estimated bedrock elevation is low. Observation points in this area are generally not very deep and do not describe the actual bedrock elevation. They do, however, describe the minimum soil depth at each location. A detailed topographical DEM, bathymetry and map of Quaternary deposits were also used. The model is based on a three-layer-principle where each layer is assumed to have similar hydrological characteristics. The uppermost layer, Z1, is characterized by the impact from surface processes, roots and biological activity. The bottom layer, Z3, is characterized by contact with the bedrock. The middle layer, Z2, is assumed to have different hydraulic qualities than Z1 and Z3. The lake sediments have been modelled according to six classes of typical deposits. The modelled soil depths show a relatively high bedrock elevation and thus small total soil depth in the major part of the area. The median soil depth has been calculated to 1.9 m, based on model results in areas with higher data density. The maximum modelled soil depth is about 13 m, just north of Lake Stocksjoen. Generally, the sediment layers in the lakes of the area consists of a

  13. A New Stochastic Modeling of 3-D Mud Drapes Inside Point Bar Sands in Meandering River Deposits

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yanshu, E-mail: yys6587@126.com [Yangtze University, School of Geosciences (China)

    2013-12-15

    The environment of major sediments of eastern China oilfields is a meandering river where mud drapes inside point bar sand occur and are recognized as important factors for underground fluid flow and distribution of the remaining oil. The present detailed architectural analysis, and the related mud drapes' modeling inside a point bar, is practical work to enhance oil recovery. This paper illustrates a new stochastic modeling of mud drapes inside point bars. The method is a hierarchical strategy and composed of three nested steps. Firstly, the model of meandering channel bodies is established using the Fluvsim method. Each channel centerline obtained from the Fluvsim is preserved for the next simulation. Secondly, the curvature ratios of each meandering river at various positions are calculated to determine the occurrence of each point bar. The abandoned channel is used to characterize the geometry of each defined point bar. Finally, mud drapes inside each point bar are predicted through random sampling of various parameters, such as number, horizontal intervals, dip angle, and extended distance of mud drapes. A dataset, collected from a reservoir in the Shengli oilfield of China, was used to illustrate the mud drapes' building procedure proposed in this paper. The results show that the inner architectural elements of the meandering river are depicted fairly well in the model. More importantly, the high prediction precision from the cross validation of five drilled wells shows the practical value and significance of the proposed method.

  14. The preglacial sediment record of Lake Ladoga, NW Russia - first results from a multi-proxy study on a 23 m sediment record

    Science.gov (United States)

    Gromig, R.; Melles, M.; Wagner, B.; Krastel, S.; Andreev, A.; Fedorov, G.; Just, J.; Wennrich, V.; Savelieva, L.; Subetto, D.; Shumilovskikh, L.

    2016-12-01

    The joint German-Russian project 'PLOT - Paleolimnological Transect' aims to recover lake sediment sequences along a more than 6000 km long longitudinal transect across the Eurasian Arctic in order to study the Late Quaternary climatic and environmental history. The eastern end of the PLOT transect is formed by the well-studied record from Lake El'gygytgyn (NE Siberia). Lake Ladoga (N 60°50' E 31°30') is Europe's largest lake, both by size and volume and forms the westernmost end of the transect. Whereas modern sedimentation as well as the Holocene and Late Glacial history of Lake Ladoga have intensely been studied, the preglacial history of the lake is poorly studied to date by sediment cores drilled in the 1930's. A seismic survey of Lake Ladoga in summer 2013 revealed unconformities in the western lake basin, which may separate preglacial sediments in isolated depressions from Late Glacial and Holocene sediment successions above. A 23 m long sediment core (Co1309) was retrieved from one of these depressions. Core Co1309 was investigated by XRF-scanning, magnetic susceptibility measurements, as well as pollen, grain-size, and bio-geochemical analyses. An age-depth model combining radiocarbon, OSL, and paleomagnetic dates is in progress. Both, the pollen results and the OSL ages from the base of the record indicate a deposition during MIS 5e (Eemian). The well sorted reddish sands from this interval contain dinoflagellates suggesting at least brackish conditions, likely due to the existence of a gateway connecting a precursor of the Baltic Sea with the White Sea via Lake Ladoga. The Late Glacial sequence consists of greyish varved clays of decreasing thickness upwards with sporadically intercalated sand layers. The Holocene sequence is composed of brownish diatomaceous silty clay with minor proportions of sand.

  15. Canada's oil sands: nuclear power in an integrated energy economy

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, E. [Alberta Energy Research Inst., Calgary, Alberta (Canada)

    2008-07-01

    This paper discusses the role of nuclear power in Canada's oil sands industry. It outlines the oil sands resource in Alberta and the various industrial projects to recover the oil from the tar sands. It points to continuing innovation in technology since the 1930's. The hydrogen required for upgrading bitumen is made from natural gas. Finally, it discusses the next wave of oil sands production technologies.

  16. Assessment of multi-trophic changes in a shallow boreal lake simultaneously exposed to climate change and aerial deposition of contaminants from the Athabasca Oil Sands Region, Canada.

    Science.gov (United States)

    Summers, Jamie C; Kurek, Joshua; Rühland, Kathleen M; Neville, Erin E; Smol, John P

    2017-08-15

    The Athabasca Oil Sands Region (AOSR) has been intensely developed for industrial bitumen extraction and upgrading since the 1980s. A paucity of environmental monitoring prior to development raises questions about baseline conditions in freshwater systems in the region and ecological responses to industrial activities. Further, climatic changes prompt questions about the relative roles of climate and industry in shaping aquatic ecosystems through time. We use aquatic bioindicators from multiple trophic levels, concentrations of petrogenic contaminants (dibenzothiophenes), and spectrally-inferred chlorophyll-a preserved in well-dated sediments of a closed-basin, shallow lake ~50km away from the main area of industry, in conjunction with climate observations, to assess how the biotic assemblages of a typical AOSR lake have changed during the past ~75years. We examine the contributions of the area's stressors in structuring aquatic communities. Increases in sedimentary measures of petrogenic contaminants provide clear evidence of aerial contaminant deposition from local industry since its establishment, while climate records demonstrate consistent warming and a recent period of reduced precipitation. Quantitative comparisons of biological assemblages from before and after the establishment of regional industry find significant (pshallow systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Evaluation of Augmented REality Sandtable (ARES) during Sand Table Construction

    Science.gov (United States)

    2018-01-01

    sand table, ARES, resulted in significantly higher- quality ratings overall for the terrain model based on a global rating scale, as well as...dependent measures in this study. Sand Table Construction Score Card: A 5-point Likert scale was used to identify the accuracy and quality of required...reproduced on the sand table. The quality of the map reproduced was evaluated using standard procedures of the map-drawing paradigm, such as that

  18. Sands at Gusev Crater, Mars

    Science.gov (United States)

    Cabrol, Nathalie A.; Herkenhoff, Kenneth E.; Knoll, Andrew H.; Farmer, Jack D.; Arvidson, Raymond E.; Grin, E.A.; Li, Ron; Fenton, Lori; Cohen, B.; Bell, J.F.; Yingst, R. Aileen

    2014-01-01

    Processes, environments, and the energy associated with the transport and deposition of sand at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium sand is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).

  19. Big picture thinking in oil sands tailings disposal

    Energy Technology Data Exchange (ETDEWEB)

    Boswell, J. [Thurber Engineering Ltd., Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed methods of disposing oil sands tailings. Oil sands operators are currently challenged by a variety of legislative and environmental factors concerning the creation and disposal of oil sands tailings. The media has focused on the negative ecological impact of oil sands production, and technical issues are reducing the effect of some mitigation processes. Operators must learn to manage the interface between tailings production and removal, the environment, and public opinion. The successful management of oil sand tailings will include procedures designed to improve reclamation processes, understand environmental laws and regulations, and ensure that the cumulative impacts of tailings are mitigated. Geotechnical investigations, engineering designs and various auditing procedures can be used to develop tailings management plans. Environmental screening and impact assessments can be used to develop sustainable solutions. Public participation and environmental mediation is needed to integrate the public, environmental and technical tailings management strategies. Operators must ensure public accountability for all stakeholders. tabs., figs.

  20. Oil sands mining and reclamation cause massive loss of peatland and stored carbon

    Science.gov (United States)

    Rooney, Rebecca C.; Bayley, Suzanne E.; Schindler, David W.

    2012-01-01

    We quantified the wholesale transformation of the boreal landscape by open-pit oil sands mining in Alberta, Canada to evaluate its effect on carbon storage and sequestration. Contrary to claims made in the media, peatland destroyed by open-pit mining will not be restored. Current plans dictate its replacement with upland forest and tailings storage lakes, amounting to the destruction of over 29,500 ha of peatland habitat. Landscape changes caused by currently approved mines will release between 11.4 and 47.3 million metric tons of stored carbon and will reduce carbon sequestration potential by 5,734–7,241 metric tons C/y. These losses have not previously been quantified, and should be included with the already high estimates of carbon emissions from oil sands mining and bitumen upgrading. A fair evaluation of the costs and benefits of oil sands mining requires a rigorous assessment of impacts on natural capital and ecosystem services. PMID:22411786

  1. Environmental Impacts of Sand Exploitation. Analysis of Sand Market

    Directory of Open Access Journals (Sweden)

    Marius Dan Gavriletea

    2017-06-01

    Full Text Available Sand is an indispensable natural resource for any society. Despite society’s increasing dependence on sand, there are major challenges that this industry needs to deal with: limited sand resources, illegal mining, and environmental impact of sand mining. The purpose of this paper is twofold: to present an overview of the sand market, highlighting the main trends and actors for production, export and import, and to review the main environmental impacts associated with sand exploitation process. Based on these findings, we recommend different measures to be followed to reduce negative impacts. Sand mining should be done in a way that limits environmental damage during exploitation and restores the land after mining operations are completed.

  2. Effectiveness of SCADA Systems in Control of Green Sands Properties

    Directory of Open Access Journals (Sweden)

    Ignaszak Z.

    2016-03-01

    Full Text Available The paper undertakes an important topic of evaluation of effectiveness of SCADA (Supervisory Control and Data Acquisition systems, used for monitoring and control of selected processing parameters of classic green sands used in foundry. Main focus was put on process studies of properties of so-called 1st generation molding sands in the respect of their preparation process. Possible methods of control of this processing are presented, with consideration of application of fresh raw materials, return sand (regenerate and water. The studies conducted in one of European foundries were aimed at pointing out how much application of new, automated plant of sand processing incorporating the SCADA systems allows stabilizing results of measurement of selected sand parameters after its mixing. The studies concerned two comparative periods of time, before an implementation of the automated devices for green sands processing (ASMS - Automatic Sand Measurement System and MCM – Main Control Module and after the implementation. Results of measurement of selected sand properties after implementation of the ASMS were also evaluated and compared with testing studies conducted periodically in laboratory.

  3. Oil-sands giants leaving smaller environmental footprints

    International Nuclear Information System (INIS)

    Stonehouse, D.

    1999-01-01

    Suncor Energy and Syncrude Canada are both investing billions of dollars to increase production at their mining facilities near Fort McMurray, Alberta. The two oil-sand giants will be spending a good portion of their investment (almost $1 billion) to improve their environmental performance. Both companies are focusing on reducing their energy use to cut production costs and to reduce carbon dioxide (CO 2 ) emissions. Currently, oil-sand mining accounts for the largest industrial use of electricity in Alberta. This produces tremendous amounts of greenhouse gases such as CO 2 which has been linked to global warming. By year 2006, all of Syncrude's processing equipment will be replaced by energy-efficient equipment. Shovel/truck/hydrotransport will replace the dragline/bucket-wheel/conveyor system used in the past. New technology designed to improve bitumen recovery and increase upgrading processing yields is also expected to decrease emissions by 5 million tonnes per year. Syncrude will also construct a $60 million gas turbine generator for its Aurora project. Sulphur dioxide (SO 2 ) emissions which cause acid rain, are also on the decline at both Syncrude and Suncor. Suncor will reduce its energy use through the construction of a $315 million cogeneration plant which will generate 220 MV of electricity for its operations, along with waste heat that will be used to separate the heavy oil from the sand. The cogeneration plant will be 45 per cent more efficient that current operations. Both companies have planted millions of trees and shrubs to reclaim nearly 3,000 hectares of land. The tailings from oil-sand mining are currently being captured in settling basins. Both companies have long range plans for dealing with tailings. The first is called water capping which involves layering fresh water over tailing deposits to create a lake. The second is called composite tails, which involves mixing the tailings with gypsum and sand to make them settle faster

  4. Influence of precipitation, landscape and hydrogeomorphic lake features on pelagic allochthonous indicators in two connected ultraoligotrophic lakes of North Patagonia

    Energy Technology Data Exchange (ETDEWEB)

    Queimalinos, Claudia, E-mail: queimalinosc@comahue-conicet.gob.ar [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Reissig, Mariana; Dieguez, Maria del Carmen [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Arcagni, Marina; Ribeiro Guevara, Sergio [Laboratorio de Analisis por Activacion Neutronica (LAAN), Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Av. Bustillo 9500, R8402AGP Bariloche, Rio Negro (Argentina); Campbell, Linda [School of Environmental Studies, Saint Mary' s University, 923 Robie Street, Halifax, Nova Scotia, Canada B3H-3C3 (Canada); Soto Cardenas, Carolina [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Rapacioli, Raul [Facultad de Ingenieria, Universidad Nacional del Comahue, Buenos Aires1400, Q8300IBX Neuquen (Argentina); and others

    2012-06-15

    We investigated the terrestrial influence on two chained deep ultraoligotrophic lakes of North Patagonia (Argentina) through the seasonal analysis of two pelagic allochthonous indicators: i) water color, as a proxy of allochthonous dissolved organic matter in lakes; and ii) the color to chlorophyll a ratio (Color:Chla), as an indicator of the relationship between allochthonous and autochthonous carbon pools. We also evaluated the potential transfer pathways of the allochthonous dissolved organic matter into the pelagic food webs of these deep lakes, including the natural zooplankton {delta}{sup 13}C in the analysis. The dynamics of the allochthonous indicators were related to the precipitation regime, water level fluctuations, and hydrogeomorphic and catchment features of lakes Moreno East and Moreno West. The water color (absorbance at 440 nm) was extremely low (< 0.28 m{sup -1}) in both lakes regardless of the season. However, precipitation and snowmelt regimes drove the increase and decrease of water color, respectively. A significant positive relationship between the zooplankton bulk {delta}{sup 13}C with the water color would suggest an input of allochthonous organic carbon into the pelagic consumers. The incorporation of the dissolved allochthonous material into higher trophic levels is likely favored by the bacterivorous behavior of planktonic organisms, mixotrophic flagellates and ciliates, which dominate the pelagic food webs of these Patagonian lakes. Morphometric aspects, mainly the higher water residence time, led to lower values of allochthony in Moreno East compared to Moreno West, probably accentuated by its upper position in the lake chain. Overall, our results suggest that these allochthonous signals can bring insight into the magnitude of the interaction between terrestrial environments and lake ecosystems, even in extremely clear and ultraoligotrophic systems, such as the Andean Patagonian lakes. - Highlights: Black-Right-Pointing-Pointer Pelagic

  5. Watershed land use effects on lake water quality in Denmark

    DEFF Research Database (Denmark)

    Nielsen, Anders; Trolle, Dennis; Søndergaard, Martin

    2012-01-01

    Mitigating nutrient losses from anthropogenic nonpoint sources is today of particular importance for improving the water quality of numerous freshwater lakes worldwide. Several empirical relationships between land use and in-lake water quality variables have been developed, but they are often weak......, which can in part be attributed to lack of detailed information about land use activities or point sources. We examined a comprehensive data set comprising land use data, point-source information, and in-lake water quality for 414 Danish lakes. By excluding point-source-influenced lakes (n = 210....... Relationships between TP and agricultural land use were even stronger for lakes with rivers in their watershed (55%) compared to lakes without (28%), indicating that rivers mediate a stronger linkage between landscape activity and lake water quality by providing a “delivery” mechanism for excess nutrients...

  6. Preliminary Report on Unique Laminated Holocene Sediments from the Qarun Lake in Egypt

    Directory of Open Access Journals (Sweden)

    Marks Leszek

    2016-06-01

    Full Text Available The Lake Qarun (Faiyum Oasis, northern Egypt is a relic of the much larger Holocene lake. Past lake levels and extensions were reconstructed, based on setting of archaeological sites scattered along northern paleoshores of the ancient lake. However, geoarcheological works did not yield enough data to establish continuous environmental history of the lake. A deep drilling FA-1 on the southeastern shore of the lake, performed in 2014, supplied with a core, 26 m long that is the one of the longest lake sediment cores in northeastern Africa. The basal section of the core consisted of thin-laminated diatom marly deposits, underlain at the Late Pleistocene/Holocene boundary by coarse-grained sands. The sediment lamine were quite well developed, especially in the lower part of the core. Preliminary results indicated annually deposited sediment sequence with seasonality signals provided by microlamine of diatoms, calcite, organic matter and clastic material. Early Holocene varved sediments from the Faiyum Oasis supplied with exceptional paleoenvironmental data for northeastern Africa, which enriched a record from previous logs drilled at the southwestern margin of the Qarun Lake.

  7. Suspended-sediment budget, flow distribution, and lake circulation for the Fox Chain of Lakes in Lake and McHenry Counties, Illinois, 1997-99

    Science.gov (United States)

    Schrader, David L.; Holmes, Robert R.

    2000-01-01

    tributaries to the Fox Chain of Lakes. With the exception of Grass Lake Outlet at Lotus Woods, most of the bed sediments are sand size or larger. The bed material at the streamflow-gaging station at Grass Lake Outlet at Lotus Woods contains 31.5 percent silt- and clay-sized particles. The bed material at Nippersink Creek near Spring Grove also has higher silt content (10.7 percent) than the bed material found in the Fox River at Wilmot (2.1 percent) and Johnsburg (1.3 percent). Additionally, water velocities at 80 cross sections in the Fox Chain of Lakes were collected to provide sample circulation patterns during two separate 1-week periods, and discharge was measured at 18 locations in the lakes. These data were collected to be available for use in hydrodynamic models.

  8. Spatial distribution of radionuclides in Lake Michigan biota near the Big Rock Point Nuclear Plant

    International Nuclear Information System (INIS)

    Wahlgren, M.A.; Yaguchi, E.M.; Nelson, D.M.; Marshall, J.S.

    1974-01-01

    A survey was made of four groups of biota in the vicinity of the Big Rock Point Nuclear Plant near Charlevoix, Michigan, to determine their usefulness in locating possible sources of plutonium and other radionuclides to Lake Michigan. This 70 MW boiling-water reactor, located on the Lake Michigan shoreline, was chosen because its fuel contains recycled plutonium, and because it routinely discharges very low-level radioactive wastes into the lake. Samples of crayfish (Orconectes sp.), green algae (Chara sp. and Cladophora sp.), and an aquatic macrophyte (Potamogeton sp.) were collected in August 1973, at varying distances from the discharge and analyzed for 239 240 Pu, 90 Sr, and five gamma-emitting radionuclides. Comparison samples of reactor waste solution have also been analyzed for these radionuclides. Comparisons of the spatial distributions of the extremely low radionuclide concentrations in biota clearly indicated that 137 Cs, 134 Cs, 65 Zn, and 60 Co were released from the reactor; their concentrations decreased exponentially with increasing distance from the discharge. Conversely, concentrations of 239 240 Pu, 95 Zr, and 90 Sr showed no correlation with distance, suggesting any input from Big Rock was insignificant with respect to the atmospheric origin of these isotopes. The significance of these results is discussed, particularly with respect to current public debate over the possibility of local environmental hazards associated with the use of plutonium as a nuclear fuel. (U.S.)

  9. Modeling and management of pit lake water chemistry 1: Theory

    International Nuclear Information System (INIS)

    Castendyk, D.N.; Eary, L.E.; Balistrieri, L.S.

    2015-01-01

    Highlights: • Review of pit lake literature in the context of pit lake predictions. • Review of approaches used to predict pit wall-rock runoff and leachate. • Review of approaches used to generate a pit lake water balance. • Review of approaches used to generate a hydrodynamic prediction. • Review of approaches used to generate a geochemical prediction of a future pit lake. - Abstract: Pit lakes are permanent hydrologic/landscape features that can result from open pit mining for metals, coal, uranium, diamonds, oil sands, and aggregates. Risks associated with pit lakes include local and regional impacts to water quality and related impacts to aquatic and terrestrial ecosystems. Stakeholders rely on predictive models of water chemistry to prepare for and manage these risks. This paper is the first of a two part series on the modeling and management of pit lakes. Herein, we review approaches that have been used to quantify wall-rock runoff geochemistry, wall-rock leachate geochemistry, pit lake water balance, pit lake limnology (i.e. extent of vertical mixing), and pit lake water quality, and conclude with guidance on the application of models within the mine life cycle. The purpose of this paper is to better prepare stakeholders, including future modelers, mine managers, consultants, permitting agencies, land management agencies, regulators, research scientists, academics, and other interested parties, for the challenges of predicting and managing future pit lakes in un-mined areas

  10. To See the World in a Grain of Sand: Recognizing the Origin of Sand Specimens by Diffuse Reflectance Infrared Fourier Transform Spectroscopy and Multivariate Exploratory Data Analysis

    Science.gov (United States)

    Pezzolo, Alessandra De Lorenzi

    2011-01-01

    The diffuse reflectance infrared Fourier transform (DRIFT) spectra of sand samples exhibit features reflecting their composition. Basic multivariate analysis (MVA) can be used to effectively sort subsets of homogeneous specimens collected from nearby locations, as well as pointing out similarities in composition among sands of different origins.…

  11. Changes in water and sediment exchange between the Changjiang River and Poyang Lake under natural and anthropogenic conditions, China.

    Science.gov (United States)

    Gao, Jian Hua; Jia, Jianjun; Kettner, Albert J; Xing, Fei; Wang, Ya Ping; Xu, Xia Nan; Yang, Yang; Zou, Xin Qing; Gao, Shu; Qi, Shuhua; Liao, Fuqiang

    2014-05-15

    To study the fluvial interaction between Changjiang River and Poyang Lake, we analyze the observed changes of riverine flux of the mid-upstream of Changjiang River catchment, the five river systems of Poyang Lake and Poyang Lake basin. Inter-annual and seasonal variations of the water discharge and sediment exchange processes between Changjiang River and Poyang Lake are systematically explored to determine the influence of climate change as well as human impact (especially the Three Gorges Dam (TGD)). Results indicate that climate variation for the Changjiang catchment and Poyang Lake watershed is the main factor determining the changes of water exchanges between Changjiang River and Poyang Lake. However, human activities (including the emplacement of the TGD) accelerated this rate of change. Relative to previous years (1956-1989), the water discharge outflow from Poyang Lake during the dry season towards the Changjiang catchment increased by 8.98 km(3)y(-1) during 2003-2010. Evidently, the water discharge flowing into Poyang Lake during late April-late May decreased. As a consequence, water storage of Poyang Lake significantly reduced during late April-late May, resulting in frequent spring droughts after 2003. The freshwater flux of Changjiang River towards Poyang Lake is less during the flood season as well, significantly lowering the magnitude and frequency of the backflow of the Changjiang River during 2003-2010. Human activities, especially the emplacement and operation of the TGD and sand mining at Poyang Lake impose a major impact on the variation of sediment exchange between Changjiang main river and Poyang Lake. On average, sediments from Changjiang River deposited in Poyang Lake before 2000. After 2000, Changjiang River no longer supplied sediment to Poyang Lake. As a consequence, the sediment load of Changjiang River entering the sea increasingly exists of sediments from Lake Poyang during 2003-2010. As a result, Poyang Lake converted from a

  12. Evolution of alkaline lakes - Lake Van case study

    Science.gov (United States)

    Tillman Meyer, Felix; Viehberg, Finn; Bahroun, Sonya; Wolf, Annabel; Immenhauser, Adrian; Kwiecien, Ola

    2017-04-01

    Lake Van in Eastern Anatolia (Turkey) is the largest terminal soda lake on Earth. The lake sedimentary profile covers ca. 600 ka (Stockhecke et al. 2014) Based on lithological changes, the presence of freshwater microfossils and close-to-freshwater pH value in the pore water, members of ICDP PALEOVAN concluded that Lake Van might have started as an open lake. Here we show paleontological and geochemical evidence in favour of this idea and constrain the time, when Lake Van likely transformed into a closed lake. Additionally we provide the first conceptual model of how this closure may have happened. Our archives of choice are inorganic and biogenic carbonates, separated by wet sieving. We identified microfossil assemblages (fraction > 125 µm) and performed high-resolution oxygen isotope (delta18O) and elemental (Mg/Ca, Sr/Ca) analyses of the fraction plants growing in the photic zone as food supply. These two aspects point to an increasing salinity in a shallowing lake. The delta18O values of inorganic carbonates are relatively low during the initial phase of Lake Van and increase abruptly (ca. 7‰) after 530 ka BP. At approximately the same time combination of Sr/Ca and Mg/Ca data suggest first occurrence of aragonite. Again, these findings suggest geochemical changes of the lake water concurrent with transition documented by microfossils. Comparison between Lake Van and Lake Ohrid (Lacey et al. 2016) delta18O data, precludes regional climate change (e.g.: increased evaporation) as the main driver of observed changes. With no evidence for increased volcanic or tectonic activity (e.g.: tephra layers, deformation structures, slumping) in the Lake Van sedimentary profile around 530 ka, it seems unlikely that a pyroclastic flow blocked the outflow of the lake. Alternatively, a portion of inflow has been diverged which might have caused a change in the hydrological balance and lake level falling below its outlet. However, as no geomorphological data confirming this

  13. Oil sands terrestrial habitat and risk modeling for disturbance and reclamation - Phase I report

    Energy Technology Data Exchange (ETDEWEB)

    Welham, C. [FORRx Consulting Inc., Belcarra, BC (Canada)

    2010-11-15

    The main purpose of this study is to build a framework that includes risk management and strategic decision-making to assess the impact of natural and industrial disturbance on ecosystem products and services and on the existence of habitat for terrestrial species in Alberta's Lower Athabasca planning region. This will include an evaluation of the impact of disturbance, conservation and reclamation activities associated with oil sands development both at the lease and regional levels. The basecase scenario, established in Phase I, includes a dendrochronology study of the link between climate and tree growth in the sub boreal region that comprises oil sands mining, an analysis of habitat availability for 10 wildlife species compared with reclamation activities on the Kearl Lake mine, and an examination of the potential for development of high levels of water stress in recent reclamation plantations at the Kearl Lake mine. Four tree species of the subboreal forests of Alberta and Saskatchewan were considered for the dendrochronology study: the white spruce or Picea glauca, the black spruce or Picea mariana, the jack pine or Pinus banksiana, and the trembling aspen or Populus tremuloides. This study shows that the water stress observed during the year has restricted the radial growth of white spruce and a link has been established between radial growth and increasing season precipitation and summer temperatures. The purposes of the habitat suitability analysis were to list habitats suitability models that could be applied to Alberta boreal forests, distinguish the parameters used in those models that can be simulated with an ecosystem simulation model, simulate the reclamation prescriptions detailed in the Kearl Lake EIA documents with the ecosystem simulation model and generate output suitable for populating each habitat suitability model. The establishment of ecologically viable reclamation plans in the oil sands region can be hard to manage regarding the

  14. Zebra mussels invade Lake Erie muds

    Science.gov (United States)

    Berkman, Paul Arthur; Haltuch, Melissa A.; Tichich, Emily; Garton, David W.; Kennedy, Gregory W.; Gannon, John E.; Mackey, Scudder D.; Fuller, Jonathan A.; Liebenthal, Dale L.

    1998-01-01

    Zebra mussels (Dreissena polymorpha) originated in western Russia but have now become widespread in Europe and North America. They are widely known for their conspicuous invasion of rocks and other hard substrates in North American and European watersheds. We have found beds of zebra mussels directly colonizing sand and mud sediments each year across hundreds of square kilometres of North America's Lake Erie. This transformation of sedimentary habitats into mussel beds represents an unforeseen change in the invasive capacity of this species.

  15. Biomagnification of mercury through lake trout (Salvelinus namaycush) food webs of lakes with different physical, chemical and biological characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Kidd, Karen A., E-mail: kiddk@unbsj.ca [Canadian Rivers Institute and Biology Department, University of New Brunswick, Saint John, NB, Canada E2L 4L5 (Canada); Muir, Derek C.G., E-mail: derek.muir@ec.gc.ca [Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6 (Canada); Evans, Marlene S., E-mail: marlene.evans@ec.gc.ca [Aquatic Contaminants Research Division, Environment Canada, Saskatoon, SK, Canada S7N 3H5 (Canada); Wang, Xioawa, E-mail: xiaowa.wang@ec.gc.ca [Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6 (Canada); Whittle, Mike [Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6 (Canada); Swanson, Heidi K., E-mail: heidikswanson@yahoo.ca [Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9 (Canada); Johnston, Tom, E-mail: tjohnston@laurentian.ca [Cooperative Freshwater Ecology Unit, Ontario Ministry of Natural Resources, and Biology Department, Laurentian University, Sudbury, ON, Canada P3E 2C6 (Canada); Guildford, Stephanie, E-mail: sguildfo@d.umn.edu [Department of Biology and Large Lakes Observatory, University of Minnesota Duluth, 2205 5th St., Duluth, MN, 55812 (United States)

    2012-11-01

    Mercury (Hg) biomagnification in aquatic ecosystems remains a concern because this pollutant is known to affect the health of fish-eating wildlife and humans, and the fish themselves. The 'rate' of mercury biomagnification is being assessed more frequently using stable nitrogen isotope ratios ({delta}{sup 15}N), a measure of relative trophic position of biota within a food web. Within food webs and across diverse systems, log-transformed Hg concentrations are significantly and positively related to {delta}{sup 15}N and the slopes of these models vary from one study to another for reasons that are not yet understood. Here we compared the rates of Hg biomagnification in 14 lake trout lakes from three provinces in Canada to understand whether any characteristics of the ecosystems explained this among-system variability. Several fish species, zooplankton and benthic invertebrates were collected from these lakes and analyzed for total Hg (fish only), methyl Hg (invertebrates) and stable isotopes ({delta}{sup 15}N; {delta}{sup 13}C to assess energy sources). Mercury biomagnification rates varied significantly across systems and were higher for food webs of larger (surface area), higher nutrient lakes. However, the slopes were not predictive of among-lake differences in Hg in the lake trout. Results indicate that among-system differences in the rates of Hg biomagnification seen in the literature may be due, in part, to differences in ecosystem characteristics although the mechanisms for this variability are not yet understood. -- Highlights: Black-Right-Pointing-Pointer Mercury biomagnifies through aquatic food webs to toxic levels in top predator fishes. Black-Right-Pointing-Pointer Among-system differences in mercury transfer through food webs occur but have not been explained. Black-Right-Pointing-Pointer Diverse lakes supporting lake trout were compared to understand the ecosystem processes that affect mercury biomagnification. Black-Right-Pointing

  16. Comparative analysis of fiscal terms for Alberta oil sands and international heavy and conventional oils

    International Nuclear Information System (INIS)

    Van Meurs, P.

    2007-01-01

    There are considerable differences between international heavy oil and Alberta oil sands projects, notably the high viscosity of the bitumen in the oil sands reservoirs. The oil sands bitumen do not flow to wells without heating the bitumen, thereby adding to the already high cost of Alberta oil sand operations. This report provided an economic comparison of Alberta oil sands and international heavy oil projects. It also included a brief scoping review to compare with conventional oil regimes. Full exploration costs including the costs of dry holes were allocated to conventional oil operations in order to obtain a proper comparison. This investigation included the costs of dry holes. The report was a follow up to an earlier study released on April 12, 2007 on the preliminary fiscal evaluation of Alberta oil sand terms. The report provided an economic framework and described project selection. It then provided a discussion of production, costs and price data. Four adjusted projects were presented and compared with Alberta. The Venezuelan royalty formula was also discussed. Last, the report provided a detailed fiscal analysis. Comparisons were offered with Cold Lake and Athabasca Mine. A review of some other fiscal systems applicable to conventional oil were also outlined. It was concluded that Alberta oil sands developments are very competitive. It would be possible to modestly increase government revenues, without affecting the international competitive position of Alberta with respect to conventional oil. There is also some possibility to increase the base royalty on the Alberta oil sands without losing competitiveness. tabs., figs

  17. Salt content impact on the unsaturated property of bentonite-sand buffer backfilling materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Ming [Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000 (China); Zhang Huyuan, E-mail: p1314lvp@yahoo.com.cn [Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000 (China); Jia Lingyan; Cui Suli [Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou 730000 (China)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer SWCC and infiltration process of bentonite-sand mixtures is researched. Black-Right-Pointing-Pointer The k{sub u} of bentonite-sand mixtures was evaluated as the buffer backfilling materials. Black-Right-Pointing-Pointer Salt content impacting on the unsaturated property of bentonite-sand materials is small. - Abstract: Bentonite mixed with sand is often considered as possible engineered barrier in deep high-level radioactive waste disposal in China. In the present work, the vapor transfer technique and water infiltration apparatus were used to measure the soil water characteristic curve (SWCC) and unsaturated hydraulic conductivity (k{sub u}) of bentonite-sand mixtures (B/S) effected by salt content. Results show, the water-holding capacity and k{sub u} increase slightly with the concentration of Na{sup +} in pore liquid increasing from 0 g/L to 12 g/L, similar with the solution concentration of Beishan groundwater in China. Salt content in the laboratory produced only one order of magnitude increase in k{sub u}, which is the 'safe' value. The different pore liquid concentrations used in this study led to small differences in thickness of diffuse double layer of bentonite in mixtures, this might explain why some differences have been found in final values of k{sub u}.

  18. Stabilizing eroding streambanks in sand drift areas of the Lake States.

    Science.gov (United States)

    Edward A. Hansen

    1968-01-01

    Banks are stabilized to protect adjacent high-value items such as cabins and campgrounds, or to reduce reservoir or lake sedimentation rates. Also, bank stabilization is undertaken as one part of fish habitat improvement programs. Rock rip-rap is the best material for bank stabilization in most cases. It does not deteriorate with time and it blends in well with the...

  19. Regional transport of a chemically distinctive dust: Gypsum from White Sands, New Mexico (USA)

    Science.gov (United States)

    White, Warren H.; Hyslop, Nicole P.; Trzepla, Krystyna; Yatkin, Sinan; Rarig, Randy S.; Gill, Thomas E.; Jin, Lixin

    2015-03-01

    The White Sands complex, a National Monument and adjoining Missile Range in southern New Mexico, occupies the dry bed of an ice-age lake where an active gypsum dunefield abuts erodible playa sediments. Aerosols entrained from White Sands are sometimes visible on satellite images as distinct, light-colored plumes crossing the Sacramento Mountains to the east and northeast. The IMPROVE network (Interagency Monitoring of PROtected Visual Environments) operates long-term aerosol samplers at two sites east of the Sacramento range. In recent years a spring pulse of sulfate aerosol has appeared at these sites, eclipsing the regional summer peak resulting from atmospheric reactions of sulfur dioxide emissions. A significant fraction of this spring sulfate is contributed by gypsum and other salts from White Sands, with much of the sulfur in coarse particles and concentrations of calcium and strontium above regional levels. The increase in these gypsiferous species coincides with a drought following a period of above-average precipitation. White Sands and the IMPROVE samplers together provide a natural laboratory: a climatically sensitive dust source that is both well characterized and chemically distinct from its surroundings, with a signature that remains identifiable at long-term observatories 100-200 km downwind.

  20. On the Size Distribution of Sand

    DEFF Research Database (Denmark)

    Sørensen, Michael

    2016-01-01

    A model is presented of the development of the size distribution of sand while it is transported from a source to a deposit. The model provides a possible explanation of the log-hyperbolic shape that is frequently found in unimodal grain size distributions in natural sand deposits, as pointed out......-distribution, by taking into account that individual grains do not have the same travel time from the source to the deposit. The travel time is assumed to be random so that the wear on the individual grains vary randomly. The model provides an interpretation of the parameters of the NIG-distribution, and relates the mean...

  1. The energy efficiency of oil sands extraction: Energy return ratios from 1970 to 2010

    International Nuclear Information System (INIS)

    Brandt, Adam R.; Englander, Jacob; Bharadwaj, Sharad

    2013-01-01

    It has been argued that the oil sands industry is not energy efficient: comparatively large energy inputs are required per unit of energy output from oil sands operations. Unfortunately, quantitative work to date in this area has suffered from poor data availability and uncertain methods. We apply a new methodology and new dataset to compute ERRs (energy return ratios) for the oil sands industry. We collected monthly oil sands energy consumption and output data from 1970 to 2010. Current oil sands operations have mine mouth NERs (net energy returns) of about 6 GJ output per GJ of energy consumed and point of use energy returns of about 3 GJ/GJ. Long-term trends show oil sands operations becoming significantly more efficient: point of use NER increased from about 1 GJ/GJ in 1970 to 3 GJ/GJ in 2010. These energy returns are lower than those observed in historical conventional oil operations, but low energy returns are not likely to hinder development of oil sands operations due to the large resource in place and the ability for largely self-fueled pathways to return significant amounts of energy to society for every unit of external energy supplied. - Highlights: • Oil sands operations have become significantly more energy efficient over the history of the industry. • Oil sands production is largely fueled with energy from the bitumen resource itself, making external energy returns high. • Oil sands production is still significantly less efficient than conventional oil production

  2. Aeolian responses to climate variability during the past century on Mesquite Lake Playa, Mojave Desert

    Science.gov (United States)

    Whitney, John W.; Breit, George N.; Buckingham, S.E.; Reynolds, Richard L.; Bogle, Rian C.; Luo, Lifeng; Goldstein, Harland L.; Vogel, John M.

    2015-01-01

    The erosion and deposition of sediments by wind from 1901 to 2013 have created large changes in surface features of Mesquite Lake playa in the Mojave Desert. The decadal scale recurrence of sand-sheet development, migration, and merging with older dunes appears related to decadal climatic changes of drought and wetness as recorded in the precipitation history of the Mojave Desert, complemented by modeled soil-moisture index values. Historical aerial photographs, repeat land photographs, and satellite images document the presence and northward migration of a mid-20th century sand sheet that formed during a severe regional drought that coincided with a multi-decadal cool phase of the Pacific Decadal Oscillation (PDO). The sand sheet slowly eroded during the wetter conditions of the subsequent PDO warm phase (1977–1998) due to a lack of added sediment. Sand cohesion gradually increased in the sand sheet by seasonal additions of salt and clay and by re-precipitation of gypsum, which resulted in the wind-carving of yardangs in the receding sand sheet. Smaller yardangs were aerodynamically shaped from coppice dunes with salt-clay crusts, and larger yardangs were carved along the walls and floor of trough blowouts. Evidence of a 19th century cycle of sand-sheet formation and erosion is indicated by remnants of yardangs, photographed in 1901 and 1916, that were found buried in the mid-20th century sand sheet. Three years of erosion measurements on the playa, yardangs, and sand sheets document relatively rapid wind erosion. The playa has lowered 20 to 40 cm since the mid-20th century and a shallow deflation basin has developed since 1999. Annually, 5–10 cm of surface sediment was removed from yardang flanks by a combination of wind abrasion, deflation, and mass movement. The most effective erosional processes are wind stripping of thin crusts that form on the yardang surfaces after rain events and the slumping of sediment blocks from yardang flanks. These wind

  3. Quantifying the impact of bathymetric changes on the hydrological regimes in a large floodplain lake: Poyang Lake

    Science.gov (United States)

    Yao, Jing; Zhang, Qi; Ye, Xuchun; Zhang, Dan; Bai, Peng

    2018-06-01

    The hydrological regime of a lake is largely dependent on its bathymetry. A dramatic water level reduction has occurred in Poyang Lake in recent years, coinciding with significant bed erosion. Few studies have focused on the influence of bathymetric changes on the hydrological regime in such a complex river-lake floodplain system. This study combined hydrological data and a physically based hydrodynamic model to quantify the influence of the bathymetric changes (1998-2010) on the water level spatiotemporal distribution in Poyang Lake, based on a dry year (2006), a wet year (2010) and an average year (2000-2010). The following conclusions can be drawn from the results of this study: (1) The bed erosion of the northern outlet channel averaged 3 m, resulting in a decrease in the water level by 1.2-2 m in the northern channels (the most significantly influenced areas) and approximately 0.3 m in the central lake areas during low-level periods. The water levels below 16 m and 14 m were significantly affected during the rising period and recession period, respectively. The water level reduction was enhanced due to lower water levels. (2) The water surface profiles adjusted, and the rising and recession rates of the water level increased by 0.5-3.1 cm/d at the lake outlet. The bathymetric influence extended across the entire lake due to the emptying effect, resulting in a change in the water level distribution. The average annual outflow increased by 6.8%. (3) The bathymetric changes contributed approximately 14.4% to the extreme low water level in autumn 2006 and enhanced the drought in the dry season. This study quantified the impact of the bathymetric changes on the lake water levels, thereby providing a better understanding of the potential effects of continued sand mining operations and providing scientific explanations for the considerable variations in the hydrological regimes of Poyang Lake. Moreover, this study attempts to provide a reference for the assessment of

  4. Sanding dust from nanoparticle-containing paints: Physical characterisation

    International Nuclear Information System (INIS)

    Koponen, I K; Jensen, K A; Schneider, T

    2009-01-01

    Increasing use of nanoparticles in different industrial applications has raised a new potential health risk to the workers as well as to the consumers. This study investigates the particle size distributions of sanding dust released from paints produced with and without engineered nanoparticles. Dust emissions from sanding painted plates were found to consist of five size modes; three modes under 1 μm and two modes around 1 and 2 μm. We observed that the sander was the only source of particles smaller than 50 nm and they dominated the number concentration spectra. Mass and surface area spectra were dominated by the 1 and 2 μm modes. Addition of nanoparticles caused only minor changes in the geometric mean diameters of the particle modes generated during sanding of two paints doped with 17 nm TiO2 and 95 nm Carbon Black nanoparticles as compared to the size modes generated during sanding a conventional reference paint. However, the number concentrations in the different size modes varied considerably in between the two NP-doped paints and the reference paint. Therefore, from a physical point of view, there may be a difference in the exposure risk during sanding surfaces covered with nanoparticle-based paints as compared to sanding conventional paints.

  5. Ground penetrating radar water content mapping of golf course green sand layers

    Science.gov (United States)

    Information on the spatial distribution of water content across the sand layer component of a golf course green can be important to golf course superintendents for evaluating drainage effectiveness and scheduling irrigation. To estimate the bulk water content of the sand layer at point locations ac...

  6. Modeling fine-scale geological heterogeneity-examples of sand lenses in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Comunian, Alessandro; Oriani, Fabio

    2013-01-01

    that hamper subsequent simulation. Transition probability (TP) and multiple-point statistics (MPS) were employed to simulate sand lens heterogeneity. We used one cross-section to parameterize the spatial correlation and a second, parallel section as a reference: it allowed testing the quality......Sand lenses at various spatial scales are recognized to add heterogeneity to glacial sediments. They have high hydraulic conductivities relative to the surrounding till matrix and may affect the advective transport of water and contaminants in clayey till settings. Sand lenses were investigated...... on till outcrops producing binary images of geological cross-sections capturing the size, shape and distribution of individual features. Sand lenses occur as elongated, anisotropic geobodies that vary in size and extent. Besides, sand lenses show strong non-stationary patterns on section images...

  7. Uranium distribution in relation to sedimentary facies, Kern Lake, California

    International Nuclear Information System (INIS)

    Merifield, P.M.; Carlisle, D.; Idiz, E.; Anderhalt, R.; Reed, W.E.; Lamar, D.L.

    1980-04-01

    Kern Lake has served as a sink for drainage from the southern Sierra Nevada and, in lesser amounts, from the southern Temblor Range. Both areas contain significant uranium source rocks. The uranium content in Holocene Kern Lake sediments correlates best with the mud (silt and clay) fraction. It correlates less well with organic carbon. Biotite grains could account for much of the uranium in the sand fraction, and perhaps the silt fraction as well. The data suggest that fixation of uranium by adsorption on mineral grains is a dominant process in this lake system. Further work is required to determine the importance of cation-exchange of uranium on clays and micas and of organically complexed uranium adsorbed to mineral surfaces. These findings also raise the question of whether uranium transport down the Kern River occurs largely as uranium adsorbed to mineral surfaces

  8. FORMATION OF THE FOREST CENOSIS AT THE BOTTOM OF THE DRIED UP LAKES IN DRY STEPPE ZONE OF THE CHECHEN REPUBLIC

    Directory of Open Access Journals (Sweden)

    R. S. Erzhapova

    2012-01-01

    Full Text Available At the present time the lake Generalskiy completely went dry, water surface of the lake Maerskiy is a little more than 1 hectare. The bottom of the lake Generalskiy is completely overgrown by woody, shrubby and grassy vegetation. Was formed here biocenosis with their flora and fauna, which is a kind of «island of life» among the surrounding Sands. In the article the systematic list of the vegetation cover are given.

  9. Before-after, control-impact analysis of evidence for the impacts of water level on Walleye, Northern Pike and Yellow Perch in lakes of the Rainy-Namakan complex (MN, USA and ON, CA.

    Directory of Open Access Journals (Sweden)

    James H Larson

    Full Text Available Water level (WL fluctuations in lakes influence many aspects of ecosystem processes. Concern about the potential impact of WL fluctuations on fisheries was one of the factors that motivated the decision in 2000 to alter the management of WL in the Rainy-Namakan reservoir complex (on the border between the U.S. state of Minnesota and the Canadian province of Ontario. We used a Before-After, Control-Impact (BACI framework to identify potential impacts of the change in WL management to Walleye, Northern Pike and Yellow Perch catch per unit effort (CPUE. The CPUE of these species from 1990-1999 and from 2005-2014 were compared in four impact lakes (Lake Kabetogama, Namakan Lake, Rainy Lake and Sand Point Lake and two control lakes (Lake of the Woods and Lake Vermilion using a simple Bayesian model. Changes in fish CPUE in the impact lakes were often similar to changes that occurred in at least one control lake. The only change that was not similar to changes in control lakes was an increase of Yellow Perch in Lake Kabetogama. The two control lakes often differed substantially from each other, such that if only one had been available our conclusions about the role of WL management on fisheries would be very different. In general, identifying cause-and-effect relationships in observational field data is very difficult, and the BACI analysis used here does not specify a causative mechanism, so co-occurring environmental and management changes may obscure the effect of WL management.

  10. Dissolved organic matter fluorescence at wavelength 275/342 nm as a key indicator for detection of point-source contamination in a large Chinese drinking water lake.

    Science.gov (United States)

    Zhou, Yongqiang; Jeppesen, Erik; Zhang, Yunlin; Shi, Kun; Liu, Xiaohan; Zhu, Guangwei

    2016-02-01

    Surface drinking water sources have been threatened globally and there have been few attempts to detect point-source contamination in these waters using chromophoric dissolved organic matter (CDOM) fluorescence. To determine the optimal wavelength derived from CDOM fluorescence as an indicator of point-source contamination in drinking waters, a combination of field campaigns in Lake Qiandao and a laboratory wastewater addition experiment was used. Parallel factor (PARAFAC) analysis identified six components, including three humic-like, two tryptophan-like, and one tyrosine-like component. All metrics showed strong correlation with wastewater addition (r(2) > 0.90, p CDOM fluorescence at 275/342 nm was the most responsive wavelength to the point-source contamination in the lake. Our results suggest that pollutants in Lake Qiandao had the highest concentrations in the river mouths of upstream inflow tributaries and the single wavelength at 275/342 nm may be adapted for online or in situ fluorescence measurements as an early warning of contamination events. This study demonstrates the potential utility of CDOM fluorescence to monitor water quality in surface drinking water sources. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. The evolution of a mining lake - From acidity to natural neutralization

    Energy Technology Data Exchange (ETDEWEB)

    Sienkiewicz, Elwira, E-mail: esienkie@twarda.pan.pl; Gąsiorowski, Michał, E-mail: mgasior@twarda.pan.pl

    2016-07-01

    Along the border of Poland and Germany (central Europe), many of the post-mining lakes have formed “an anthropogenic lake district”. This study presents the evolution of a mining lake ecosystem (TR-33) based on subfossil phyto- and zooplankton, isotopic data (δ{sup 13}C, δ{sup 15}N), elemental analyses of organic carbon and nitrogen (C/N ratio and TOC) and sedimentological analyses. Recently, lake TR-33 became completely neutralized from acidification and an increase in eutrophication began a few years ago. However, the lake has never been neutralized by humans; only natural processes have influenced the present water quality. From the beginning of the existence of the lake (1920s) to the present, we can distinguish four stages of lake development: 1) very shallow reservoir without typical lake sediments but with a sand layer containing fine lignite particles and very poor diatom and cladoceran communities; 2) very acidic, deeper water body with increasing frequencies of phyto- and zooplankton; 3) transitional period (rebuilding communities of diatoms and Cladocera), meaning a deep lake with benthic and planktonic fauna and flora with wide ecological tolerances; and 4) a shift to circumneutral conditions with an essential increase in planktonic taxa that prefer more fertile waters (eutrophication). In the case of lake TR-33, this process of natural neutralization lasted approximately 23 years. - Highlights: • Originally acid water lake had poor phyto- and zooplankton populations. • Process of natural neutralization lasted approximately 23 years. • Presently, lake's ecosystem is similar to other shallow lakes in the region. • Changes in the lake are representative for other mine lakes.

  12. Assessment of lake sensitivity to acidic deposition in national parks of the Rocky Mountains

    Science.gov (United States)

    Nanus, L.; Williams, M.W.; Campbell, D.H.; Tonnessen, K.A.; Blett, T.; Clow, D.W.

    2009-01-01

    The sensitivity of high-elevation lakes to acidic deposition was evaluated in five national parks of the Rocky Mountains based on statistical relations between lake acid-neutralizing capacity concentrations and basin characteristics. Acid-neutralizing capacity (ANC) of 151 lakes sampled during synoptic surveys and basin-characteristic information derived from geographic information system (GIS) data sets were used to calibrate the statistical models. The explanatory basin variables that were considered included topographic parameters, bedrock type, and vegetation type. A logistic regression model was developed, and modeling results were cross-validated through lake sampling during fall 2004 at 58 lakes. The model was applied to lake basins greater than 1 ha in area in Glacier National Park (n = 244 lakes), Grand Teton National Park (n = 106 lakes), Great Sand Dunes National Park and Preserve (n = 11 lakes), Rocky Mountain National Park (n = 114 lakes), and Yellowstone National Park (n = 294 lakes). Lakes that had a high probability of having an ANC concentration 3000 m, with 80% of the catchment bedrock having low buffering capacity. The modeling results indicate that the most sensitive lakes are located in Rocky Mountain National Park and Grand Teton National Park. This technique for evaluating the lake sensitivity to acidic deposition is useful for designing long-term monitoring plans and is potentially transferable to other remote mountain areas of the United States and the world.

  13. Application of the Gillette model for windblown dust at Owens Lake, CA

    Science.gov (United States)

    Ono, Duane

    Windblown dust can have significant impacts on local air pollution levels, and in cases such as dust from Africa or Asia, can have global impacts on our environment. Models to estimate particulate matter emissions from windblown dust are generally based on the local wind speed, the threshold wind speed to initiate erosion, and the soil texture of a given surface. However, precipitation, soil crusting, and soil disturbance can dramatically change the threshold wind speed and erosion potential of a surface, making modeling difficult. A low-cost sampling and analysis method was developed to account for these surface changes in a wind erosion model. Windblown dust emissions measured as PM 10 (particulate matter less than a nominal 10 μm aerodynamic diameter) have been found to be generally proportional to sand flux (also known as saltation flux). In this study, a model was used to estimate sand flux using the relationship Q=AρG/g, where Q is horizontal sand flux, A is a surface erosion potential factor, ρ is air density, g is the gravitational constant, and G=∫ u*(u*2-u*t2)dt, where u* is friction velocity and u is the threshold friction velocity of the surface. The variable A in the model was derived by comparing the measured sand flux for a given period and area to G for the same period. Sand flux was monitored at Owens Lake, CA using low-cost Cox Sand Catchers (CSCs) for monthly measurements, and more expensive electronic sensors (Sensits) to measure hourly flux rates and u. Monitors were spaced 1 km apart at 114 sites, covering one clay and three sand-dominated soil areas. Good model results relied primarily on the erosion potential A, which could be determined from CSC measurements and wind speed data. Annual values for A were found to range from 1.3 to 3.5 in the three sand areas. The value of A was an order of magnitude lower (0.2) in the less erodible clay area. Previous studies showed similar values for A of 0.7 and 2.9 for a sandy site at Owens Lake, and

  14. Dust Generation Resulting from Desiccation of Playa Systems: Studies on Mono and Owens Lakes, California

    Science.gov (United States)

    Gill, Thomas Edward

    1995-01-01

    Playas, evaporites, and aeolian sediments frequently are linked components within the Earth system. Anthropogenic water diversions from terminal lakes form playas that release fugitive dust. These actions, documented worldwide, simulate aeolian processes activated during palaeoclimatic pluvial/interpluvial transitions, and have significant environmental impacts. Pluvial lakes Russell and Owens in North America's Great Basin preceded historic Mono and Owens Lakes, now desiccated by water diversions into dust-generating, evaporite -encrusted playas. Geochemical and hydrologic cycles acting on the Owens (Dry) Lake playa form three distinct crust types each year. Although initial dust production results from deflation of surface efflorescences after the playa dries, most aerosols are created by saltation abrasion of salt/silt/clay crusts at crust/ sand sheet contacts. The warm-season, clastic "cemented" crust is slowest to degrade into dust. If the playa surface is stabilized by an unbroken, non-efflorescent crust, dust formation is discouraged. When Mono Lake's surFace elevation does not exceed 1951 meters (6400 feet), similar processes will also generate dust from its saline lower playa. Six factors--related to wind, topography, groundwater, and sediments--control dust formation at both playas. These factors were combined into a statistical model relating suspended dust concentrations to playa/lake morphometry. The model shows the extent and severity of Mono Lake dust storms expands significantly below the surface level 6376 feet (1943.5 meters). X-ray diffraction analysis of Mono Basin soils, playa sediments, and aerosols demonstrates geochemical cycling of materials through land, air and water during Mono Lake's 1982 low stand. Soils and clastic playa sediments contain silicate minerals and tephra. Saline groundwater deposited calcite, halite, thenardite, gaylussite, burkeite and glauberite onto the lower playa. Aerosols contained silicate minerals (especially

  15. Determination of trace elements in GPC fractions of oil-sand asphaltenes by INAA

    International Nuclear Information System (INIS)

    Jacobs, F.S.; Bachelor, F.W.; Filby, R.H.

    1984-01-01

    Asphaltene samples precipitated from Athabasca and Cold Lake oil-sand bitumens were separated into 12 fractions of varying molecular weight by preparative gel permeation chromatography (GPC). Each fraction was then analyzed by analytical GPC and visible spectrometry. Concentrations of As, Ce, Co, Cr, Eu, Ga, Hf, Hg, La, Ni, Sb, Sc, Se, Sm, Tb, Th, U, V, Zn, and Zr in the fractions were determined by neutron activation analysis. Molecular weights of the Athabasca fractions are generally higher than the corresponding Cold Lake fractions. Between 58% and 90% of the metal contents occur in the high molecular weight fractions of both asphaltenes. Except for V and Cr, which show biomodel distributions, all the elements have decreasing concentrations as the molecular weight of the fraction decreases. High molecular weight fractions, constituting about 55% of the whole asphaltenes, contain nonporphyrin bound vanadium compounds. It is estimated that 27% and 31% of V present in Athabasca and Cold Lake asphaltenes respectively occur as porphyrin type compounds, including vanadyl prophyrins released from the asphaltene micelle during the separation and vanadyl porphyrins bearing high-molecular-weight substituents

  16. Malaria vectors in Lake Victoria and adjacent habitats in western Kenya.

    Directory of Open Access Journals (Sweden)

    Noboru Minakawa

    Full Text Available The prevalence of malaria among the residents of the Lake Victoria basin remains high. The environment associated with the lake may maintain a high number of malaria vectors. Lake habitats including water hyacinths have been suspected to be the source of vectors. This study investigated whether malaria vectors breed in the lake habitats and adjacent backwater pools. Anopheline larvae were collected within the littoral zone of the lake and adjacent pools located along approximately 24.3 km of the lakeshore in western Kenya, and their breeding sites characterized. Three primary vector species, Anopheles arabiensis, Anopheles gambiae s.s. and Anopheles funestus s.s., and three potential vectors, were found in the lake habitats. Unexpectedly, An. arabiensis was the most dominant vector species in the lake sampling sites. Its habitats were uncovered or covered with short grass. A potential secondary malaria vector, Anopheles rivulorum, dominated the water hyacinths in the lake. Most breeding sites in the lake were limited to areas that were surrounded by tall emergent plants, including trees, and those not exposed to waves. Nearly half of adjacent habitats were lagoons that were separated from the lake by sand bars. Lagoons contained a variety of microhabitats. Anopheles arabiensis dominated open habitats, whereas An. funestus s.s. was found mainly in vegetated habitats in lagoons. The current study confirmed that several breeding sites are associated with Lake Victoria. Given that Lake Victoria is the second largest lake in the world, the lake related habitats must be extensive; therefore, making targeted vector control difficult. Further exploration is necessary to estimate the effects of lake associated habitats on malaria transmission so as to inform a rational decision-making process for vector control.

  17. Inter-annual variations in water yield to lakes in northeastern Alberta: implications for estimating critical loads of acidity

    Directory of Open Access Journals (Sweden)

    Roderick HAZEWINKEL

    2010-08-01

    Full Text Available Stable isotopes of water were applied to estimate water yield to fifty lakes in northeastern Alberta as part of an acid sensitivity study underway since 2002 in the Athabasca Oil Sands Region (AOSR. Herein, we apply site-specific water yields for each lake to calculate critical loads of acidity using water chemistry data and a steady-state water chemistry model. The main goal of this research was to improve site-specific critical load estimates and to understand the sensitivity to hydrologic variability across a Boreal Plains region under significant oil sands development pressure. Overall, catchment water yields were found to vary significantly over the seven year monitoring period, with distinct variations among lakes and between different regions, overprinted by inter-annual climate-driven shifts. Analysis of critical load estimates based on site-specific water yields suggests that caution must be applied to establish hydrologic conditions and define extremes at specific sites in order to protect more sensitive ecosystems. In general, lakes with low (high water yield tended to be more (less acid sensitive but were typically less (more affected by interannual hydrological variations. While it has been customary to use long-term water yields to define a static critical load for lakes, we find that spatial and temporal variability in water yield may limit effectiveness of this type of assessment in areas of the Boreal Plain characterized by heterogeneous runoff and without a long-term lake-gauging network. Implications for predicting acidification risk are discussed for the AOSR.

  18. Eastern Scheldt Sand, Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Andersen, A. T; Madsen, E. B.; Schaarup-Jensen, A. L.

    The present data report contains data from 13 drained triaxial tests, performed on two different sand types in the Soil Mechanics Laboratory at Aalborg University in March, 1997. Two tests have been performed on Baskarp Sand No. 15, which has already ken extensively tested in the Soil Mechanics...... Laboratory. The remaining 11 triaxial tests have ben performed on Eastern Scheldt Sand, which is a material not yet investigated at the Soil Mechanics Laboratory. In the first pari of this data report, the characteristics of the two sand types in question will be presented. Next, a description...... will described. In this connection, the procedure for preparation of the soil specimens will be presented, and the actual performance of the tests will be briefly outlined. Finally, the procedure for processing of the measurements from the laboratory in order to obtain usable data will be described. The final...

  19. HPLC-DAD-ESI/MS Identification of Light Harvesting and Light Screening Pigments in the Lake Sediments at Edmonson Point

    OpenAIRE

    Giovannetti, Rita; Alibabaei, Leila; Zannotti, Marco; Ferraro, Stefano; Petetta, Laura

    2013-01-01

    The composition of sedimentary pigments in the Antarctic lake at Edmonson Point has been investigated and compared with the aim to provide a useful analytical method for pigments separation and identification, providing reference data for future assessment of possible changes in environmental conditions. Reversed phase high performance liquid chromatography (HPLC) with electrospray-mass spectrometry (ESI-MS) detection and diode array detection (DAD) has been used to identify light screeni...

  20. Modelling assessment of End Pit Lakes meromictic potential

    International Nuclear Information System (INIS)

    2006-11-01

    The use of End Pit Lakes have been proposed as a remediation solution for oil sands reclamation and operational waters. This report modelled the main factors controlling the occurrence of stratification in Pit Lakes in order to establish design and management guidelines for the Cumulative Environmental Management Association's End Pit Lake Sub-group. The study focused on End Pit Lake size, depth, starting lake salinity concentrations, inflow rates and inflow salinity flux, and investigated their influence on density gradients. One-dimensional modelling and limited 2-D modelling simulations were conducted to examine meromictic potential for a large range of End Pit Lake configurations and conditions. Modelling results showed that fall is the governing season for determining meromixis. The expelling of salt from saline water upon ice formation and its effect on stratification potential and the effect of fresh water loading on stratification potential during spring melt events were not observed to be dominant factors governing meromictic potential for the scenarios examined in the study. Results suggested that shallow End Pit Lakes showed a high turn-over rate with seasonal heating and cooling cycles. Moderately deep End Pit Lakes demonstrated a meromictic potential that was inversely proportional to lake size and require higher starting salinities. With a 2 or 10 million m 3 /yr inflow rate and a 5 parts per thousand starting salinity, a 50 m deep End Pit Lake achieved meromixis at all 3 size ranges considered in the study. Results also showed that the rate of influent salinity decrease was the least important of the parameters influencing meromixis. It was observed that meromixis was a temporary condition in all of the End Pit Lake scenarios envisioned due to the lack of a constant, positive salt replenishment over the long term. It was concluded that further 3-D modelling is required to represent littoral areas as well as to account for extreme winter conditions. A

  1. Oil sands from Sao Paulo State, Brazil and La Brea de Chumpi, Peru: a geologic perspective

    Energy Technology Data Exchange (ETDEWEB)

    Kramers, John W [Alberta Research Council, Edmonton, AB (Canada); Santos, Paulo R. dos [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil); Gianello, Pedro T [Petroleos del Peru, Lima (Peru)

    1987-12-31

    This work describes two `non-conventional` oil sands occurrences in Peru and Brazil. The study of such occurrences has pointed out the fact that oil sands are found in widely varying geological situations and that not all oil sands have origins similar to the supergiant `conventional` deposits in Canada and Venezuela. 3 refs., 9 figs.

  2. Insight conference reports : Western Canada oil sands

    International Nuclear Information System (INIS)

    2005-01-01

    This conference presented issues of concern to the Canadian oil sands industry. Focal points included supply and the potential for market growth as well as opportunities and challenges faced by the industry in the current market. Various projects were discussed, including the Northern Lights and Fort Hill projects. Reserves and resource booking procedures were examined, as well as issues concerning the streamlining of regulatory barriers and various approaches to the Kyoto Protocol and greenhouse gas (GHG) emissions. Oil sands portfolios were reviewed as well as issues concerning the recovery of titanium and zircon, the economics of Steam Assisted Gravity Drainage (SAGD) options and innovations in technology and sub-surface risk assessment for in-situ projects. Transportation initiatives were examined as well as pipeline issues and storage infrastructure development. Issues concerning financing as well as the economic environment of the oil sands industry were also discussed. The conference featured 20 presentations, of which 5 have been catalogued separately for inclusion in this database. tabs, figs

  3. Landsat-Based Long-Term Monitoring of Total Suspended Matter Concentration Pattern Change in the Wet Season for Dongting Lake, China

    Directory of Open Access Journals (Sweden)

    Zhubin Zheng

    2015-10-01

    Full Text Available Assessing the impacts of environmental change and anthropogenic activities on the historical and current total suspended matter (TSM pattern in Dongting Lake, China, is a large challenge. We addressed this challenge by using more than three decades of Landsat data. Based on in situ measurements, we developed an algorithm based on the near-infrared (NIR band to estimate TSM in Dongting Lake. The algorithm was applied to Landsat images to derive TSM distribution maps from 1978 to 2013 in the wet season, revealing significant inter-annual and spatial variability. The relationship of TSM to water level, precipitation, and wind speed was analyzed, and we found that: (1 sand mining areas usually coincide with regions that have high TSM levels in Dongting Lake; (2 water level and seven-day precipitation were both important to TSM variation, but no significant relationship was found between TSM and wind speed or other meteorological data; (3 the increased level of sand mining in response to rapid economic growth has deeply influenced the TSM pattern since 2000 due to the resuspension of sediment; and (4 TSM variation might be associated with policy changes regarding the management of sand mining; it might also be affected by lower water levels caused by the impoundment of the Three Gorges Dam since 2000.

  4. Influence of Reclamation Process on the Ecological Quality of Reclaim Sand

    Directory of Open Access Journals (Sweden)

    Dereń M.

    2017-12-01

    Full Text Available In this article, there were presented results of research on influence of reclamation process on the ecological quality of reclaim sand with furan resin used in nonferrous foundry. The quality of reclaimed sand is mainly define by two group of chemical substances from elution of reclaimed sand: Dissolves Organic Carbon (DOC and Total Dissolves Solids (TDS. Reclaimed sand used in test was prepared in experimental thermal reclaimer and mechanical vibration reclaimer REGMAS installed in Faculty of Foundry Engineering at University Of Science and Technology in Krakow. The reference point is molding sand shaking out and crumble in jaw crusher. Test of elution was made in accredited laboratory in Center For Research and Environmental Control in Katowice up to the standard with Dissolves Organic Carbon (DOC - PN-EN 1484:1999; Total Dissolves Solids (TDS - PN-EN 15216:2010. The standard for elution test is PN-EN 12457- 4:2006. Except that we were made loss of ignition test, to check how many resin was rest on sand grains.

  5. Estimating the effects of land-use and catchment characteristics on lake water quality: Irish lakes 2004-2009

    OpenAIRE

    Curtis, John; Morgenroth, Edgar

    2013-01-01

    This paper attributes the variation in water quality across Irish lakes to a range of contributory factors such as human population, septic tanks, urban waste water treatment, phosphorous excreted by livestock, as well as catchment soil and geology. Both linear and non-linear quadratic models were estimated in the analysis, which attempts to account for point and non-point sources of pollution affecting water quality in 216 lake catchments. The models show a clear link between activities with...

  6. A Dynamical Downscaling study over the Great Lakes Region Using WRF-Lake: Historical Simulation

    Science.gov (United States)

    Xiao, C.; Lofgren, B. M.

    2014-12-01

    As the largest group of fresh water bodies on Earth, the Laurentian Great Lakes have significant influence on local and regional weather and climate through their unique physical features compared with the surrounding land. Due to the limited spatial resolution and computational efficiency of general circulation models (GCMs), the Great Lakes are geometrically ignored or idealized into several grid cells in GCMs. Thus, the nested regional climate modeling (RCM) technique, known as dynamical downscaling, serves as a feasible solution to fill the gap. The latest Weather Research and Forecasting model (WRF) is employed to dynamically downscale the historical simulation produced by the Geophysical Fluid Dynamics Laboratory-Coupled Model (GFDL-CM3) from 1970-2005. An updated lake scheme originated from the Community Land Model is implemented in the latest WRF version 3.6. It is a one-dimensional mass and energy balance scheme with 20-25 model layers, including up to 5 snow layers on the lake ice, 10 water layers, and 10 soil layers on the lake bottom. The lake scheme is used with actual lake points and lake depth. The preliminary results show that WRF-Lake model, with a fine horizontal resolution and realistic lake representation, provides significantly improved hydroclimates, in terms of lake surface temperature, annual cycle of precipitation, ice content, and lake-effect snowfall. Those improvements suggest that better resolution of the lakes and the mesoscale process of lake-atmosphere interaction are crucial to understanding the climate and climate change in the Great Lakes region.

  7. Provenance and recycling of Arabian desert sand

    Science.gov (United States)

    Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid A.; Al-Juboury, Ali I. A.

    2013-05-01

    This study seeks to determine the ultimate origin of aeolian sand in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi sands from the Red Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled sand, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune sands, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al

  8. Restoration of Black Oak (Quercus velutina) Sand Barrens via Three Different Habitat Management Approaches

    Science.gov (United States)

    Kriska, David John

    Disturbance regimes, i.e. frequent fires, historically maintained oak barrens until European settlement patterns, and eventually, Smoky the Bear and the fire suppression campaign of the U.S. Forest Service snuffed out the periodic flames. In the absence of a disturbance regime, ground layer floral composition at many historical oak sand barrens will change predominantly because of a buildup of leaf litter and shading of the soils. Termed mesophication, this process of ecological succession will drive Black Oak Sand Barrens to an alternate steady state. A survey conducted on Singer Lake Bog in Green, Ohio, demonstrated that succession shifted the community to red maple-black cherry woodlands more typical of a dry southern forest. In an attempt to revive disturbance, three restoration techniques were applied at ten degraded northeast Ohio oak barrens to contrast their effectiveness in restoring black oak sand barren flora. The three restoration treatments were select canopy tree reduction favoring 5% to 30% tree canopy cover, forest floor leaf litter removal, and prescribed fire. Vegetation responses to manipulations were monitored prior to and following treatment applications, and were compared against both baseline data from before-treatment surveys and paired control sites adjacent treated areas. Imposing disturbance successfully increased species diversity and abundance above that found across Singer Lake Bog compared to sampling made prior to and adjacent to treated areas. Select canopy tree removal exhibited the largest floral responses from targeted barrens species, i.e. graminoids. A forest floor invertebrate family (Carabidea: Coleoptera) was measured for species richness and abundance pre and post treatment, where a noticeable shift occurred away from woodland obligate ground beetles toward open grassland species. Replicating oak barren structure, prior to replicating disturbance processes, is the first step in the ecological restoration of these systems.

  9. Submarine sand ridges and sand waves in the eastern part of the China Sea

    Science.gov (United States)

    Wu, Ziyin; Li, Shoujun; Shang, Jihong; Zhou, Jieqiong; Zhao, Dineng; Liang, Yuyang

    2016-04-01

    Integrated with multi-beam and single-beam echo sounding data, as well as historical bathymetric data, submarine bathymetric maps of the eastern part of the China Sea, including the Bohai Sea, Huanghai Sea, and East China Sea, are constructed to systematically study submarine sand ridges and sand waves in the eastern part of the China Sea, combined with high-resolution seismic, sub-bottom profile and borehole data. Submarine sand ridges are extraordinarily developed in the eastern part of the China Sea, and 7 sand ridge areas can be divided from north to south, that is, the Laotieshan Channel sand ridge area in the Bohai Sea, the Korea Bay sand ridge area in the southern Huanghai Sea, the sand ridge area in the eastern Huanghai islands and the Huanghai Troughs, the Jianggang sand ridge area in the western Huanghai Sea, the sand ridge area in the East China Sea shelf, and the sand ridge and sand wave area in the Taiwan Strait and Taiwan Banks. The distribution area of the sand ridges and sand waves covers more than 450,000 km2, wherein ~10,000 km2 in the Bohai Bay, ~200,000 km2 in the Huanghai Sea, ~200,000 km2 in the East China Sea shelf, and ~40,000 km2 in the Taiwan Strait and Taiwan Banks, respectively. The great mass of sand ridges are distributed within water depth of 5-160 m, with a total length of over 160 km and a main width of 5-10 km. The inner structure of the sand ridges presents features of high-angle inclined beddings, with main lithology of sands, sand-mud alternations partly visible, and a small number of mud cores. Dating results indicate that the sand ridges in the eastern part of the China Sea are mainly developed in the Holocene. Sea-level variation dominates the sand ridge evolution in the eastern part of the China Sea since the LGM, and the sand ridges developed in the area of < 60m water depth are appeared in bad activity, meanwhile sand ridges with good activity are still developed in large scale.

  10. Review of fish diversity in the Lake Huron basin

    Science.gov (United States)

    Roseman, E.F.; Schaeffer, J.S.; Steen, P.J.

    2009-01-01

    Lake Huron has a rich aquatic habitat diversity that includes shallow embayments, numerous tributaries, shallow mid-lake reef complexes, archipelagos, and profundal regions. These habitats provide support for warm, cool, and cold water fish communities. Diversity of fishes in Lake Huron reflects post-glaciation colonization events, current climate conditions, accidental and intentional introductions of non-indigenous species, and extinctions. Most extinction events have been largely associated with habitat alterations, exploitation of fisheries, and interactions with non-indigenous species. The most recent historical survey of extirpated and imperiled species conducted in the late 1970s identified 79 fish species in Lake Huron proper and about 50 additional species in tributaries. Of those 129 species, 20 are now considered extirpated or imperiled. Extirpated species include Arctic grayling, paddlefish, weed shiner, deepwater cisco, blackfin cisco, shortnose cisco, and kiyi. Six species have declined appreciably due to loss of clear-water stream habitat: the river redhorse, river darter, black redhorse, pugnose shiner, lake chubsucker, redside dace, eastern sand darter, and channel darter. While numerous agencies, universities, and other organizations routinely monitor nearshore and offshore fish distribution and abundance, there is a need for more rigorous examination of the distribution and abundance of less-common species to better understand their ecology. This information is critical to the development of management plans aimed at ecosystem remediation and restoration.

  11. Sources and distribution of microplastics in China's largest inland lake - Qinghai Lake.

    Science.gov (United States)

    Xiong, Xiong; Zhang, Kai; Chen, Xianchuan; Shi, Huahong; Luo, Ze; Wu, Chenxi

    2018-04-01

    Microplastic pollution was studied in China's largest inland lake - Qinghai Lake in this work. Microplastics were detected with abundance varies from 0.05 × 10 5 to 7.58 × 10 5 items km -2 in the lake surface water, 0.03 × 10 5 to 0.31 × 10 5 items km -2 in the inflowing rivers, 50 to 1292 items m -2 in the lakeshore sediment, and 2 to 15 items per individual in the fish samples, respectively. Small microplastics (0.1-0.5 mm) dominated in the lake surface water while large microplastics (1-5 mm) are more abundant in the river samples. Microplastics were predominantly in sheet and fiber shapes in the lake and river water samples but were more diverse in the lakeshore sediment samples. Polymer types of microplastics were mainly polyethylene (PE) and polypropylene (PP) as identified using Raman Spectroscopy. Spatially, microplastic abundance was the highest in the central part of the lake, likely due to the transport of lake current. Based on the higher abundance of microplastics near the tourist access points, plastic wastes from tourism are considered as an important source of microplastics in Qinghai Lake. As an important area for wildlife conservation, better waste management practice should be implemented, and waste disposal and recycling infrastructures should be improved for the protection of Qinghai Lake. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Incorporation of Complex Hydrological and Socio-economic Factors for Non-point Source Pollution Control: A Case Study at the Yincungang Canal, the Lake Tai Basin of China

    Science.gov (United States)

    Yang, X.; Luo, X.; Zheng, Z.

    2012-04-01

    It is increasingly realized that non-point pollution sources contribute significantly to water environment deterioration in China. Compared to developed countries, non-point source pollution in China has the unique characteristics of strong intensity and composition complexity due to its special socioeconomic conditions. First, more than 50% of its 1.3 billion people are rural. Sewage from the majority of the rural households is discharged either without or only with minimal treatment. The large amount of erratic rural sewage discharge is a significant source of water pollution. Second, China is plagued with serious agricultural pollution due to widespread improper application of fertilizers and pesticides. Finally, there lack sufficient disposal and recycling of rural wastes such as livestock manure and crop straws. Pollutant loads from various sources have far exceeded environmental assimilation capacity in many parts of China. The Lake Tai basin is one typical example. Lake Tai is the third largest freshwater lake in China. The basin is located in the highly developed and densely populated Yangtze River Delta. While accounting for 0.4% of its land area and 2.9% of its population, the Lake Tai basin generates more than 14% of China's Gross Domestic Production (GDP), and the basin's GDP per capita is 3.5 times as much as the state average. Lake Tai is vital to the basin's socio-economic development, providing multiple services including water supply for municipal, industrial, and agricultural needs, navigation, flood control, fishery, and tourism. Unfortunately, accompanied with the fast economic development is serious water environment deterioration in the Lake Tai basin. The lake is becoming increasingly eutrophied and has frequently suffered from cyanobacterial blooms in recent decades. Chinese government has made tremendous investment in order to mitigate water pollution conditions in the basin. Nevertheless, the trend of deteriorating water quality has yet to

  13. Physical characteristics and quality of water from selected springs and wells in the Lincoln Point-Bird Island area, Utah Lake, Utah

    Science.gov (United States)

    Baskin, R.L.; Spangler, L.E.; Holmes, W.F.

    1994-01-01

    From February 1991 to October 1992, the U.S. Geological Survey, in cooperation with the Central Utah Water Conservancy District, investigated the hydrology of the Lincoln Point - Bird Island area in the southeast part of Utah Lake, Utah. The investigation included measurements of the discharge of selected springs and measurements of the physical and chemical characteristics of water from selected springs and wells in the LincolnPoint - Bird Island area. This report contains data for twenty-one distinct springs in the study area including two springs beneath the surface of Utah Lake at Bird Island. Data from this study, combined with data from previous studies, indicate that the location of springs in the Lincoln Point - Bird Island area probably is controlled by fractures that are the result of faulting. Measured discharge of springs in the Lincoln Point - Bird Island area ranged from less than 0.01 cubic foot per second to 0.84 cubic foot per second. Total discharge in the study area, including known unmeasured springs and seeps, is estimated to be about 5 cubic feet per second. Reported and measured temperatures of water from springs and wells in the Lincoln Point - Bird Island area ranged from 16.0 degrees Celsius to 36.5 degrees Celsius. Dissolved-solids con-centrations ranged from 444 milligrams per liter to 7,932 milligrams per liter, and pH ranged from 6.3 to 8.1. Physical and chemical characteristics of spring and well water from the west side of Lincoln Point were virtually identical to the physical and chemical characteristics of water from the submerged Bird Island springs, indicating a similar source for the water. Water chemistry, isotope analyses, and geothermometer calculations indicate deep circulation of water discharging from the springs and indicate that the source of recharge for the springs at Lincoln Point and Bird Island does not appear to be localized in the LincolnPoint - Bird Island area.

  14. Fish otolith geochemistry, environmental conditions and human occupation at Lake Mungo, Australia

    Science.gov (United States)

    Long, Kelsie; Stern, Nicola; Williams, Ian S.; Kinsley, Les; Wood, Rachel; Sporcic, Katarina; Smith, Tegan; Fallon, Stewart; Kokkonen, Harri; Moffat, Ian; Grün, Rainer

    2014-03-01

    Fish otoliths from the Willandra Lakes Region World Heritage Area (south-western New South Wales, Australia) have been analysed for oxygen isotopes and trace elements using in situ techniques, and dated by radiocarbon. The study focused on the lunettes of Lake Mungo, an overflow lake that only filled during flooding events and emptied by evaporation, and Lake Mulurulu, which was part of the running Willandra Creek system. Samples were collected from two different contexts: from hearths directly associated with human activity, and isolated surface finds. AMS radiocarbon dating constrains the human activity documented by five different hearths to a time span of less than 240 years around 19,350 cal. BP. These hearths were constructed in aeolian sediments with alternating clay and sand layers, indicative of fluctuating lake levels and occasional drying out. The geochemistry of the otoliths confirms this scenario, with shifts in Sr/Ca and Ba/Ca marking the entry of the fish into Lake Mungo several years before their death, and a subsequent increase in the δ18O by ˜4‰ indicating increasing evaporation of the lake. During sustained lake-full conditions there are considerably fewer traces of human presence. It seems that the evaporating Lake Mungo attracted people to harvest fish that might have become sluggish through oxygen starvation in an increasingly saline water body (easy prey hypothesis). In contrast, surface finds have a much wider range in radiocarbon age as a result of reworking, and do not necessarily indicate evaporative conditions, as shown by comparison with otoliths from upstream Lake Mulurulu.

  15. Bottom Topographic Changes of Poyang Lake During Past Decade Using Multi-temporal Satellite Images

    Science.gov (United States)

    Zhang, S.

    2015-12-01

    Poyang Lake, as a well-known international wetland in the Ramsar Convention List, is the largest freshwater lake in China. It plays crucial ecological role in flood storage and biological diversity. Poyang Lake is facing increasingly serious water crises, including seasonal dry-up, decreased wetland area, and water resource shortage, all of which are closely related to progressive bottom topographic changes over recent years. Time-series of bottom topography would contribute to our understanding of the lake's evolution during the past several decades. However, commonly used methods for mapping bottom topography fail to frequently update quality bathymetric data for Poyang Lake restricted by weather and accessibility. These deficiencies have limited our ability to characterize the bottom topographic changes and understanding lake erosion or deposition trend. To fill the gap, we construct a decadal bottom topography of Poyang Lake with a total of 146 time series medium resolution satellite images based on the Waterline Method. It was found that Poyang Lake has eroded with a rate of -14.4 cm/ yr from 2000 to 2010. The erosion trend was attributed to the impacts of human activities, especially the operation of the Three Gorge Dams, sand excavation, and the implementation of water conservancy project. A decadal quantitative understanding bottom topography of Poyang Lake might provide a foundation to model the lake evolutionary processes and assist both researchers and local policymakers in ecological management, wetland protection and lake navigation safety.

  16. Naphtha evaporation from oil sands tailings ponds

    Energy Technology Data Exchange (ETDEWEB)

    Kasperski, K.; Munoz, V.; Mikula, R. [Natural Resources Canada, Devon, AB (Canada). CANMET Western Research Centre

    2010-07-01

    The environmental impacts of volatile organic compounds (VOCs) from oil sands tailings ponds must be considered when evaluating new oil sands mining and extraction operations. Studies have suggested that only 40 percent of the solvent sent to tailings ponds is available to the environment, while the rest is irreversibly trapped. The recovery of hydrocarbons from oil sands froth process water is low. This PowerPoint presentation discussed a method of distinguishing between water and hydrocarbons at low temperatures. Samples were heated to 246 degrees C at 15 degrees C and held for 10 minutes. Heating was then resumed at 750 degrees C and held for 10 minutes in a pyrolysis phase, then cooled and reheated with an oxygen addition. The method demonstrated that the diluent distribution between the solids and water phases is misinterpreted as diluent that will evaporate, and diluent that will not evaporate. The study concluded by suggesting that the definition of recoverable and unrecoverable hydrocarbon should be re-termed as easily recoverable, and difficult to recover. tabs., figs.

  17. Fontainebleau Sand

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    2006-01-01

    The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand.......The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand....

  18. Reclamation and closure of an oil sands tailings facility

    Energy Technology Data Exchange (ETDEWEB)

    Sobkowicz, J. [Thurber Engineering Ltd., Calgary, AB (Canada); Morgenstern, N. [Alberta Univ., Edmonton, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed methods of ensuring the successful reclamation of oil sands tailings facilities. Tailings should be reclaimed as mining proceeds in order to avoid an excessive accumulation of fluid fine tailings (FFT). The volume of mature fine tailings (MFT) in ponds should be limited in order to ensure effective tailings management. The reclaimed landforms should have good geotechnical stability and be comprised of self-sustaining native vegetation. Strength is needed to allow for timely capping and initial reclamation, and stiffness is required to minimize future settlement and to allow for the construction of a closure landscape. Reclamation strategies were presented for fines-dominated tailings; sand-depleted tailings; and sand-dominated tailings. Energy Resources Conservation Board (ERCB) criteria for tailings reclamation were discussed, and various monitoring and performance assessment strategies were presented. tabs., figs.

  19. Microbial quality and safety of fresh and dried Rastrineobola argentea from Lake Victoria, Tanzania

    DEFF Research Database (Denmark)

    Baniga, Zebedayo; Dalsgaard, Anders; Mhongole, Ofred J

    2017-01-01

    the bacteriological quality of fresh and dried sardines from Lake Victoria. Sardine samples were randomly collected from main landing sites and retail markets in the city of Mwanza. Total viable counts (TVC) in fresh sardines were in the range of 5.18–7.90 log10 cfu/g while those dried on racks contained 3.......13–4.85 log10 cfu/g which were 0.75% of those dried on sand with 4.80–7.13 log10 cfu/g (p .../g and those dried on sand contained 1.18–3.32 log10 mpn/g, however, sardines dried on racks, did not contain any E. coli. Similar findings were found in the two types of dried sardines from the retail markets. Prevalence of Salmonella spp. in fresh R. argentea was 25% (n = 40), sand dried sardines at landing...

  20. Development of a bioassay to assess the toxicity of oil sands sediments to pike (Esox lucius)

    Energy Technology Data Exchange (ETDEWEB)

    Turcotte, D.; Yuan, H.; Tumber, V.; Parrott, J. [Environment Canada, Ottawa, ON (Canada); Raine, J. [Saskatchewan Univ., Saskatoon, SK (Canada)

    2010-07-01

    Pike (Esox lucius) are a commercially sought fish species that inhabit the Athabasca River, which flows through the Athabasca oil sands. The fish are exposed to natural sources of bitumen from the McMurray formation. This study was conducted to design and implement a daily-renewal bioassay to assess the toxicity of oil sands to this fish species and to obtain information regarding the development of pike exposed to bitumen. Eggs were collected and fertilized with milt from spawning wild pike captured from Lake Diefenbaker in Saskatchewan. The fertilized eggs were exposed to different concentrations of sediments or culture water only (negative controls) until complete yolk absorption of control fish, approximately 15 days post-hatch. For the rest of the experiment, brine shrimp were fed to the walleye embryos every day after hatching. The developing fish were examined for morphological deformities, survival, hatching success, and changes in weight and length. The research findings indicated that pike is less sensitive than walleye and fathead minnow to the toxicity of oil sands sediments.

  1. Managing A Lake/Aquifer System-Science, Policy, and the Public Interest

    Science.gov (United States)

    Shaver, R. B.

    2009-12-01

    Lake Isabel is a small (312 ha) natural lake located in central North Dakota in the glaciated Missouri Coteau. The average lake depth is about 1.8 m with a maximum depth of about 3.6 to 4.6 m. The lake overlies the Central Dakota aquifer complex which is comprised of three sand and gravel aquifer units that are either directly or indirectly (through leakage) hydraulically connected to the lake. The aquifer is a major water source for center pivot irrigation. During the 2001-2008 drought, lower lake levels reduced lake recreation, including leaving many boat docks unusable. Lake homeowners attribute lake level decline to irrigation pumping and believe that irrigation should be curtailed. There is no water right associated with Lake Isabel because there are no constructed works associated with the lake. Therefore, under North Dakota statute the lake cannot be protected as a prior (senior) appropriator. The lake does have standing under the public interest as defined by North Dakota statute. Evaluation of the public interest involves the integration of both science and policy. Is it in the best interest of the people of the state to prohibit ground water withdrawals for irrigation to protect the lake? This is a policy decision, not a scientific decision. The basis of the policy decision should include an economic analysis of the irrigated crops, fish, wildlife, recreation, and lake property. In addition, priority of use and lake level history should be considered. The issue can likely be resolved without scientific controversy arising from hydrologic system uncertainty. If the decision is to protect the lake at some level, the issue becomes “scientized” and the following questions need to be answered: 1) Does irrigation pumping effect changes in lake levels? 2) Is our level of scientific understanding sufficient to determine what volume of irrigation pumping will cause what amount of lake level change? 3) Given aquifer lag time response to changes in pumping and

  2. Trophic development in a volcanic lake with closed hydric balance. Lake Martignano

    International Nuclear Information System (INIS)

    Falleni, F.; Bruno, M.; Marchiori, E.; Congestri, R.; Gasperi, E.; Brambullo, M.; Amadeio, R.

    2000-01-01

    Martignano lake is a particular charming volcanic lake in the countryside of Rome. Recently it was included in a project of Regional Wildlife Park. The lack of immissaries and emissaries, the quite long renewal time and the very short homeothermic period of two-months in a year, make the lake susceptible of trophic evolution. The comparison between the present data and those from previous studies seems to confirm such a slow development towards this way, with a nutrient level (nitrate 0.97 mg/L; total phosphorus 11.14 μg/L) and chlorophyll a concentrations (10.68 μg/L), typical of mesotrophic waters. The analysis of nutrient data expressed as annual mean value in percentage from the coastal stations, suggests an under lied farming influence, and points out the need to adopt fast reduction measures, to lower the phosphorus load in acceptable levels for the lake ecosystem [it

  3. Tailings dewatering in the oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Longo, S.; Labelle, M. [Golder Paste Technology, Sudbury, ON (Canada); Wislesky, I. [Golder Associates Ltd., Calgary, AB (Canada)

    2010-07-01

    Alberta's Directive 074 was established to reduce fluid tailings produced during oil sands extraction processes. This PowerPoint presentation examined some of the dewatering strategies available for oil sands operators and provided recommendations for implementing a dewatering plan. Sites must be evaluated in order to determine their chemistry, mineralogy, and the total quantity of material to be handled. The availability of potential additives must also be considered. Process technologies must be selected in relation to the operator's depositional strategy. Each site will require its own unique dewatering and depositional strategy. Dewatering technologies include thickening; in-line flocculation; centrifuge; co-mingling; and various new technologies such as electro-osmosis. Laboratory testing programs include index tests, primary stream thickening, and mini-pilot plant testing. The performance of various testing formats was evaluated. Thickening and depositional techniques were reviewed. tabs., figs.

  4. HPLC-DAD-ESI/MS identification of light harvesting and light screening pigments in the lake sediments at Edmonson Point.

    Science.gov (United States)

    Giovannetti, Rita; Alibabaei, Leila; Zannotti, Marco; Ferraro, Stefano; Petetta, Laura

    2013-01-01

    The composition of sedimentary pigments in the Antarctic lake at Edmonson Point has been investigated and compared with the aim to provide a useful analytical method for pigments separation and identification, providing reference data for future assessment of possible changes in environmental conditions. Reversed phase high performance liquid chromatography (HPLC) with electrospray-mass spectrometry (ESI-MS) detection and diode array detection (DAD) has been used to identify light screening and light harvesting pigments. The results are discussed in terms of local environmental conditions.

  5. Thin, Conductive Permafrost Surrounding Lake Fryxell Indicates Salts From Past Lakes, McMurdo Dry Valleys, Antarctica

    Science.gov (United States)

    Foley, N.; Tulaczyk, S. M.; Gooseff, M. N.; Myers, K. F.; Doran, P. T.; Auken, E.; Dugan, H. A.; Mikucki, J.; Virginia, R. A.

    2017-12-01

    In the McMurdo Dry Valleys (MDV), permafrost should be thick and liquid water rare. However, despite the well below zero mean annual temperature in this cryospheric desert, liquid water can be found in lakes, summer melt streams, subglacial outflow, and - recent work has shown - underneath anomalously thin permafrost. In part, this niche hydrosphere is maintained by the presence of salts, which depress the freezing point of water to perhaps as cold as -10° Celsius. We detected widespread salty water across the MDV in lakes and at depth using a helicopter-borne Time Domain Electromagnetic (TDEM) sensor. By using the presence of brines to mark the transition from frozen permafrost (near the surface) to unfrozen ground (at depth), we have created a map of permafrost thickness in Lower Taylor Valley (LTV), a large MDV with a complex history of glaciation and occupation by lakes. Our results show that permafrost is thinner ( 200m) than would be expected based on geothermal gradient measurements (up to 1000m), a result of the freezing point depression caused by salt and potentially enhanced by an unfinished transient freezing process. Near Lake Fryxell, a large, brackish lake in the center of LTV, permafrost is very thin (about 30-40m) and notably more electrically conductive than more distal permafrost. This thin ring of conductive permafrost surrounding the lake basin most likely reflects the high presence of salts in the subsurface, preventing complete freezing. These salts may be a remnant of the salty bottom waters of a historic larger lake (LGM glacially dammed Lake Washburn) or the remnant of salty basal water from a past advance of Taylor Glacier, which now sits many km up-valley but is known to contain brines which currently flow onto the surface and directly into the subsurface aquifer.

  6. Impact of water-level changes to aquatic vegetation in small oligotrophic lakes

    Directory of Open Access Journals (Sweden)

    Egert VANDEL

    2016-06-01

    Full Text Available This study demonstrates the effect of drastic water-level changes to the aquatic vegetation in three small oligotrophic lakes situated in Kurtna Kame Field in north-eastern Estonia. The area holds around 40 lakes in 30 km2 of which 18 lakes are under protection as Natura Habitat lakes (Natura 2000 network. The area is under a strong human impact as it is surrounded by oil shale mines, sand quarry, peat harvesting field etc. The most severe impact comes from the groundwater intake established in 1972 in the vicinity of three studied lakes. The exploitation of groundwater led to drastic water-level drops. In 1980s the water-level drops were measured to be up to 3 to 4 meters compared to the levels of 1946. Lake Martiska and Lake Kuradijärv were severely affected and only 29% and 45% of lake area respectively and 21% of initial volume remained. Both lakes were described as oligotrophic lakes before severe human impact and held characteristic macrophytes such as Isoëtes lacustris L., Sparganium angustifolium Michx and Lobelia dortmanna L. As the water level declined the lakes lost their rare characteristic species and can now be described more as a meso- or even eutrophic lakes. When the volume of groundwater abstraction decreased in the 1990s the water levels started to recover but did not reach the natural levels of pre-industrialized era. Also the vegetation did not show any signs of recovery. In 2012 the pumping rates increased again causing a new rapid decline in water levels which almost exceed the previous minimum levels. The water-level monitoring alongside with the macrophyte monitoring data gives us a good case study on how the long term abrupt water-level changes can affect the aquatic vegetation

  7. Study of Black Sand Particles from Sand Dunes in Badr, Saudi Arabia Using Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Haider Abbas Khwaja

    2015-08-01

    Full Text Available Particulate air pollution is a health concern. This study determines the microscopic make-up of different varieties of sand particles collected at a sand dune site in Badr, Saudi Arabia in 2012. Three categories of sand were studied: black sand, white sand, and volcanic sand. The study used multiple high resolution electron microscopies to study the morphologies, emission source types, size, and elemental composition of the particles, and to evaluate the presence of surface “coatings or contaminants” deposited or transported by the black sand particles. White sand was comprised of natural coarse particles linked to wind-blown releases from crustal surfaces, weathering of igneous/metamorphic rock sources, and volcanic activities. Black sand particles exhibited different morphologies and microstructures (surface roughness compared with the white sand and volcanic sand. Morphological Scanning Electron Microscopy (SEM and Laser Scanning Microscopy (LSM analyses revealed that the black sand contained fine and ultrafine particles (50 to 500 nm ranges and was strongly magnetic, indicating the mineral magnetite or elemental iron. Aqueous extracts of black sands were acidic (pH = 5.0. Fe, C, O, Ti, Si, V, and S dominated the composition of black sand. Results suggest that carbon and other contaminant fine particles were produced by fossil-fuel combustion and industrial emissions in heavily industrialized areas of Haifa and Yanbu, and transported as cloud condensation nuclei to Douf Mountain. The suite of techniques used in this study has yielded an in-depth characterization of sand particles. Such information will be needed in future environmental, toxicological, epidemiological, and source apportionment studies.

  8. A semi-automated approach for mapping geomorphology of El Bardawil Lake, Northern Sinai, Egypt, using integrated remote sensing and GIS techniques

    Directory of Open Access Journals (Sweden)

    Nabil Sayed Embabi

    2014-06-01

    Full Text Available Among the other coastal lakes of the Mediterranean northern coast of Egypt, Bardawil Lake is a unique lagoon, as it is fed only by seawater. The lagoon is composed of two main basins, and several other internal small basins interconnected to one another. Although the general geomorphologic characteristics are treated in some regional studies, we used a semi-automated approach based on a wide variety of digital image processing for mapping the major geomorphological landforms of the lake on a medium scale of 1:250,000. The approach is based primarily on data fusion of Landsat ETM+ image, and validated by other ancillary spatial data (e.g. topographic maps, Google images and GPS in situ data. Interpretations of high resolution space images by Google Earth and the large-scale topographic maps (1:25,000, in specific, revealed new microforms and some detailed geomorphologic aspects with the aid of GPS measurements. Small sand barriers, submerged sand dunes, tidal channels, fans and flats, and micro-lagoons are the recurrent forms in the lake. The approach used in this study could be widely applied to study the low-lying coastal lands along the Nile Delta. However, it is concluded from geological data and geomorphologic aspects that Bardawil Lake is of a tectonic origin; it was much deeper than it is currently, and has been filled with sediments mostly since the Flandrian transgression (∼8–6 ka bp.

  9. Bison and the oil sands industry

    International Nuclear Information System (INIS)

    Pauls, R.W.

    1998-01-01

    Syncrude's Mildred Lake oil sands development project is located within the central boreal mixed wood forest in an area supporting traditional land uses, including trapping and harvesting of wildlife and plant materials by Fort McKay First Nation residents, in a community within 10 km of the Syncrude development. Reclamation requirements and standards in Alberta specify that the reclamation process must restore a landscape capability equivalent to, or better than that existing before disturbance. Syncrude is committed to complying with all provincial requirements and guidelines in all aspects of its business, including land reclamation. A five year research program has been established to determine the feasibility of reclaiming a portion of the landscape to support wood bison and bison subspecies once indigenous to this area. The current project may be expanded as a pilot commercial ranching venture to explore its commercial viability as a business venture by the Fort McKay First nations

  10. A comparison of seed banks across a sand dune successional gradient at Lake Michigan dunes (Indiana, USA)

    Science.gov (United States)

    Leicht-Young, S. A.; Pavlovic, N.B.; Grundel, R.; Frohnapple, K.J.

    2009-01-01

    In habitats where disturbance is frequent, seed banks are important for the regeneration of vegetation. Sand dune systems are dynamic habitats in which sand movement provides intermittent disturbance. As succession proceeds from bare sand to forest, the disturbance decreases. At Indiana Dunes National Lakeshore, we examined the seed banks of three habitat types across a successional gradient: foredunes, secondary dunes, and oak savanna. There were differences among the types of species that germinated from each of the habitats. The mean seed bank density increased across the successional gradient by habitat, from 376 to 433 to 968 seeds m-2, but with foredune and secondary dune seed bank densities being significantly lower than the savanna seed bank density. The number of seeds germinated was significantly correlated with soil organic carbon, demonstrating for this primary successional sequence that seed density increases with stage and age. The seed bank had much lower species richness than that of the aboveground vegetation across all habitats. Among sites within a habitat type, the similarity of species germinated from the seed banks was very low, illustrating the variability of the seed bank even in similar habitat types. These results suggest that restoration of these habitats cannot rely on seed banks alone. ?? 2008 Springer Science+Business Media B.V.

  11. HPLC-DAD-ESI/MS Identification of Light Harvesting and Light Screening Pigments in the Lake Sediments at Edmonson Point

    Directory of Open Access Journals (Sweden)

    Rita Giovannetti

    2013-01-01

    Full Text Available The composition of sedimentary pigments in the Antarctic lake at Edmonson Point has been investigated and compared with the aim to provide a useful analytical method for pigments separation and identification, providing reference data for future assessment of possible changes in environmental conditions. Reversed phase high performance liquid chromatography (HPLC with electrospray-mass spectrometry (ESI-MS detection and diode array detection (DAD has been used to identify light screening and light harvesting pigments. The results are discussed in terms of local environmental conditions.

  12. New generation expandable sand screens

    OpenAIRE

    Syltøy, Christer

    2014-01-01

    Master's thesis in Petroleum engineering This thesis aims to give a general insight into sand control and various sorts of sand control measures and applications of sand control tools. Special focus will be given to expandable sand screens – a technology which came about in the late 1990’s through the use of flexible, expandable tubulars as base pipe in sand screens. More specifically Darcy’s Hydraulic Endurance Screens, a compliant sand screen system using hydraulic activation, and the fu...

  13. Saltation of non-spherical sand particles.

    Directory of Open Access Journals (Sweden)

    Zhengshi Wang

    Full Text Available Saltation is an important geological process and the primary source of atmospheric mineral dust aerosols. Unfortunately, no studies to date have been able to precisely reproduce the saltation process because of the simplified theoretical models used. For example, sand particles in most of the existing wind sand movement models are considered to be spherical, the effects of the sand shape on the structure of the wind sand flow are rarely studied, and the effect of mid-air collision is usually neglected. In fact, sand grains are rarely round in natural environments. In this paper, we first analyzed the drag coefficients, drag forces, and starting friction wind speeds of sand grains with different shapes in the saltation process, then established a sand saltation model that considers the coupling effect between wind and the sand grains, the effect of the mid-air collision of sand grains, and the effect of the sand grain shape. Based on this model, the saltation process and sand transport rate of non-spherical sand particles were simulated. The results show that the sand shape has a significant impact on the saltation process; for the same wind speed, the sand transport rates varied for different shapes of sand grains by as much as several-fold. Therefore, sand shape is one of the important factors affecting wind-sand movement.

  14. Evaluation of methods to sample fecal indicator bacteria in foreshore sand and pore water at freshwater beaches.

    Science.gov (United States)

    Vogel, Laura J; Edge, Thomas A; O'Carroll, Denis M; Solo-Gabriele, Helena M; Kushnir, Caitlin S E; Robinson, Clare E

    2017-09-15

    Fecal indicator bacteria (FIB) are known to accumulate in foreshore beach sand and pore water (referred to as foreshore reservoir) where they act as a non-point source for contaminating adjacent surface waters. While guidelines exist for sampling surface waters at recreational beaches, there is no widely-accepted method to collect sand/sediment or pore water samples for FIB enumeration. The effect of different sampling strategies in quantifying the abundance of FIB in the foreshore reservoir is unclear. Sampling was conducted at six freshwater beaches with different sand types to evaluate sampling methods for characterizing the abundance of E. coli in the foreshore reservoir as well as the partitioning of E. coli between different components in the foreshore reservoir (pore water, saturated sand, unsaturated sand). Methods were evaluated for collection of pore water (drive point, shovel, and careful excavation), unsaturated sand (top 1 cm, top 5 cm), and saturated sand (sediment core, shovel, and careful excavation). Ankle-depth surface water samples were also collected for comparison. Pore water sampled with a shovel resulted in the highest observed E. coli concentrations (only statistically significant at fine sand beaches) and lowest variability compared to other sampling methods. Collection of the top 1 cm of unsaturated sand resulted in higher and more variable concentrations than the top 5 cm of sand. There were no statistical differences in E. coli concentrations when using different methods to sample the saturated sand. Overall, the unsaturated sand had the highest amount of E. coli when compared to saturated sand and pore water (considered on a bulk volumetric basis). The findings presented will help determine the appropriate sampling strategy for characterizing FIB abundance in the foreshore reservoir as a means of predicting its potential impact on nearshore surface water quality and public health risk. Copyright © 2017 Elsevier Ltd. All rights

  15. Assessment Method of Overheating Degree of a Spent Moulding Sand with Organic Binder, After the Casting Process

    Directory of Open Access Journals (Sweden)

    Dańko R.

    2013-06-01

    Full Text Available A proper management of sand grains of moulding sands requires knowing basic properties of the spent matrix after casting knocking out. This information is essential from the point of view of the proper performing the matrix recycling process and preparing moulding sands with reclaimed materials. The most important parameter informing on the matrix quality - in case of moulding sands with organic binders after casting knocking out - is their ignition loss. The methodology of estimating ignition loss of spent moulding sands with organic binder - after casting knocking out - developed in AGH, is presented in the paper. This method applies the simulation MAGMA software, allowing to determine this moulding sand parameter already at the stage of the production preparation.

  16. The use of LANDSAT-1 imagery in mapping and managing soil and range resources in the Sand Hills region of Nebraska

    Science.gov (United States)

    Seevers, P. M. (Principal Investigator); Drew, J. V.

    1976-01-01

    The author has identified the following significant results. Evaluation of ERTS-1 imagery for the Sand Hills region of Nebraska has shown that the data can be used to effectively measure several parameters of inventory needs. (1) Vegetative biomass can be estimated with a high degree of confidence using computer compatable tape data. (2) Soils can be mapped to the subgroup level with high altitude aircraft color infrared photography and to the association level with multitemporal ERTS-1 imagery. (3) Water quality in Sand Hills lakes can be estimated utilizing computer compatable tape data. (4) Center pivot irrigation can be inventoried from satellite data and can be monitored regarding site selection and relative success of establishment from high altitude aircraft color infrared photography. (5) ERTS-1 data is of exceptional value in wide-area inventory of natural resource data in the Sand Hills region of Nebraska.

  17. Tidal modulated flow and sediment flux through Wax Lake Delta distributary channels: Implications for delta development

    Directory of Open Access Journals (Sweden)

    K. Hanegan

    2015-03-01

    Full Text Available In this study, a Delft3D model of the Wax Lake Delta was developed to simulate flow and sediment flux through delta distributary channels. The model was calibrated for tidal constituents as well as velocity and sediment concentration across channel transects. The calibrated model was then used to simulate full spring–neap tidal cycles under constant low flow upstream boundary conditions, with grain size variation in suspended load represented using two sediment fractions. Flow and sediment flux results through distributary channel cross-sections were examined for spatial and temporal variability with the goal of characterizing the role of tides in sediment reworking and delta development. The Wax Lake Delta has prograded through channel extension, river mouth bar deposition, and channel bifurcation. Here we show that tidal modulation of currents influences suspended sand transport, and spatial acceleration through distributary channels at low tides is sufficient to suspend sand in distal reaches during lower flows. The basinward-increasing transport capacity in distributary channels indicates that erosive channel extension could be an important process, even during non-flood events.

  18. Early Cretaceous trypanosomatids associated with fossil sand fly larvae in Burmese amber

    Directory of Open Access Journals (Sweden)

    George Poinar Jr

    2007-08-01

    Full Text Available Early Cretaceous flagellates with characters typical of trypanosomatids were found in the gut of sand fly larvae, as well as in surrounding debris, in Burmese amber. This discovery supports a hypothesis in which free-living trypanosomatids could have been acquired by sand fly larvae in their feeding environment and then carried transtadially into the adult stage. At some point in time, specific genera were introduced into vertebrates, thus establishing a dixenous life cycle.

  19. Athabasca, Cold Lake and the future

    International Nuclear Information System (INIS)

    McFarland, J.D.

    1993-01-01

    It is suggested that Alberta oil sands have the potential to sustain and increase the wealth creation capacity of the Canadian petroleum sector now and well into the next century. Realizing this potential in the present-day competitive and interconnected world crude oil market is a challenge to be addressed in four areas: markets, operations, technology, and stakeholder support. Real price improvement in the world oil market is not expected in the near future, given near-static demand and a continuously increasing worldwide supply potential. Even in such a market, there are specialized niches where Canadian heavy oil should be competitive. These markets are continental and are mainly high- and medium-conversion refineries and upgraders. Demand for Canadian heavy oil is forecast to grow ca 4%/y to over 800,000 bbl/d by 2000. Supply will closely track demand 1995-98 and be slightly below demand before 1995 and after 1998. Improvements in existing operations to lower production costs and increase efficiency are being made at the Cold Lake and Syncrude facilities. The development of technology to improve recovery and lower supply costs will trigger further development, and impressive gains have already been realized as a result from ongoing research. The final condition needed to allow the oil sand sector to realize its potential is informed and supportive stakeholders (investors, customers, governments, and communities), who need to understand the unique attributes and potential awards of the oil sand business. 6 figs

  20. Effect of Natural Sand Percentages on Fatigue Life of Asphalt Concrete Mixture

    Directory of Open Access Journals (Sweden)

    Nahla Yassub Ahmed

    2016-03-01

    Full Text Available The design of a flexible pavement requires the knowledge of the material properties which are characterized by stiffness and fatigue resistance. The fatigue resistance relates the number of load cycles to failure with the strain level applied to the asphalt mixture. The main objective of this research is the evaluation of the fatigue life of asphalt mixtures by using two types of fine aggregate having different percentages. In this study, two types of fine aggregate were used natural sand (desert sand and crushed sand. The crushed sand was replaced by natural sand (desert sand with different percentages (0%, 25%, 75% and 100% by the weight of the sand (passing sieve No.8 and retained on sieve No.200 and one type of binder (40/50 penetration from Al-Daurah refinery. The samples of beams were tested by four point bending beam fatigue test at the control strain mode (250, 500 and 750 microstrain while the loading frequency (5Hz and testing temperature (20oC according to (AASHTO T321. The experimental work showed that fatigue life (Nf and initial flexural stiffness increased when control strain decreased for asphalt mixtures. Acceptable fatigue life at 750 microstrain was obtained with asphalt concrete mixtures containing 100% crushed sand as well as asphalt concrete contained 25% natural sand. The asphalt concrete contained 100% and 75% of natural sand exhibited high fatigue life at low level of microstrain (250. The main conclusion of this study found that best proportion of natural sand to be added to an asphaltic concrete mixture is falling within the range (0% and 25% by weight of fraction (passing No.8 and retained on No.200 sieve .

  1. Faunistic assemblages of a sublittoral coarse sand habitat of the northwestern Mediterranean

    Directory of Open Access Journals (Sweden)

    Eva Pubill

    2011-02-01

    Full Text Available The sublittoral megabenthic assemblages of a northwestern Mediterranean coarse sandy beach exploited for the bivalve Callista chione were studied. The spatial and bathymetric variability of its distinctive faunal assemblages was characterised by quantitative sampling performed with a clam dredge. The taxa studied were Mollusca Bivalvia and Gastropoda, Crustacea Decapoda, Echinodermata and Pisces, which accounted for over 99% of the total biomass. Three well-differentiated species assemblages were identified: (1 assemblage MSS (Medium Sand Shallow in medium sand (D50=0.37 mm and shallow waters (mean depth =6.5 m, (2 assemblage CSS (Coarse Sand Shallow in coarse sand (D50=0.62 mm in shallow waters (mean depth =6.7 m, and (3 assemblage CSD (Coarse Sand Deep in coarse sand (D50=0.64 mm in deeper waters (mean depth =16.2 m. Assemblage MSS was characterised by the codominance of the bivalves Mactra stultorum and Acanthocardia tuberculata. C. chione was dominant in both density and biomass in assemblages CSS and CSD. The occurrence of the crab Thia scutellata also characterised assemblage CSS, whereas the occurrence of the sea urchin Echinocardium mediterraneum characterised assemblage CSD. A depth breaking point of around 10 m determined the discontinuity between assemblages CSS and CSD, which was related to the closure depth of the beaches in the study area. Species richness was highest in the coarse sand communities; however, Shannon-Wiener diversity and Pielou equitability indexes were higher in the shallow fine sand community.

  2. Contaminant trends in lake trout and walleye from the Laurentian Great Lakes

    Science.gov (United States)

    DeVault, David S.; Hesselberg, Robert J.; Rodgers, Paul W.; Feist, Timothy J.

    1996-01-01

    Trends in PCBs, DDT, and other contaminants have been monitored in Great Lakes lake trout and walleye since the 1970s using composite samples of whole fish. Dramatic declines have been observed in concentrations of PCB, ΣDDT, dieldrin, and oxychlordane, with declines initially following first order loss kinetics. Mean PCB concentrations in Lake Michigan lake trout increased from 13 μg/g in 1972 to 23 μg/g in 1974, then declined to 2.6 μg/g by 1986. Between 1986 and 1992 there was little change in concentration, with 3.5 μg/g observed in 1992. ΣDDT in Lake Michigan trout followed a similar trend, decreasing from 19.2 μg/g in 1970 to 1.1 μg/g in 1986, and 1.2 μg/g in 1992. Similar trends were observed for PCBs and ΣDDT in lake trout from Lakes Superior, Huron and Ontario. Concentrations of both PCB and ΣDDT in Lake Erie walleye declined between 1977 and 1982, after which concentrations were relatively constant through 1990. When originally implemented it was assumed that trends in the mean contaminant concentrations in open-lake fish would serve as cost effective surrogates to trends in the water column. While water column data are still extremely limited it appears that for PCBs in lakes Michigan and Superior, trends in lake trout do reasonably mimic those in the water column over the long term. Hypotheses to explain the trends in contaminant concentrations are briefly reviewed. The original first order loss kinetics used to describe the initial decline do not explain the more recent leveling off of contaminant concentrations. Recent theories have examined the possibilities of multiple contaminant pools. We suggest another hypothesis, that changes in the food web may have resulted in increased bioaccumulation. However, a preliminary exploration of this hypothesis using a change point analysis was inconclusive.

  3. Liquefaction resistance of calcareous sands

    International Nuclear Information System (INIS)

    Sandoval Vallejo, Eimar

    2012-01-01

    Calcareous sands are unique in terms of their origin, mineralogy, shape, fragility and intra particle porosity. This article presents results from an experimental program carried out to study the liquefaction resistance of a calcareous sand retrieved from Cabo Rojo at Puerto Rico. The experimental program included mineralogical characterization, index properties, and undrained cyclic triaxial tests on isotropically consolidated reconstituted samples. Due to the large variation in the calcareous sand properties, results are compared with previous researches carried out on other calcareous sands around the world. Results showed a wide range in the liquefaction resistance of the studied calcareous sands. Cabo Rojo sand experienced greater liquefaction resistance than most of the calcareous sands used for comparison. Important differences in the excess pore pressure generation characteristics were also found.

  4. Successful water management for the oil sands industry

    International Nuclear Information System (INIS)

    Braun, B.

    2003-01-01

    Water is a key requirement to produce oil from thermal oil sands projects. Historically, water was considered as a renewable resource that could be used when necessary. Water use is currently examined in a wider context. Canadian Natural Resources Limited has used fresh water for thermal projects in the past, including its thermal operations at Primrose and Wolf Lake. However, technical advancements have made it possible to use recycled water. This allows companies to survive within their licenses while increasing production. Other advances include the use of brackish water, and innovations such as using depleted reservoir sections to store water to increase the use of recycled water. It was noted that brackish water resources need to be mapped and understood in greater detail. The objective is to use brackish water at a cost equal to, or less, than fresh water

  5. Marine Point Forecasts

    Science.gov (United States)

    will link to the zone forecast and then allow further zooming to the point of interest whereas on the Honolulu, HI Chicago, IL Northern Indiana, IN Lake Charles, LA New Orleans, LA Boston, MA Caribou, ME

  6. Evaluating regional water scarcity: Irrigated crop water budgets for groundwater management in the Wisconsin Central Sands

    Science.gov (United States)

    Nocco, M. A.; Kucharik, C. J.; Kraft, G.

    2013-12-01

    Regional water scarcity dilemmas between agricultural and aquatic land users pervade the humid northern lake states of Wisconsin, Minnesota, and Michigan, where agricultural irrigation relies on groundwater drawn from shallow aquifers. As these aquifers have strong connectivity to surface waters, irrigation lowers water levels in lakes and wetlands and reduces stream discharges. Irrigation expansion has cultivated a 60-year water scarcity dilemma in The Wisconsin Central Sands, the largest irrigated region in the humid northern lake states, dedicated to potato, maize, and processing vegetable production. Irrigation has depleted Wisconsin Central Sands surface waters, lowering levels in some lakes by over 2 m and drying some coldwater trout streams. Aquatic ecosystems, property values, and recreational uses in some surface waters have been devastated. While the causal link between pumping and surface water stress is established, understanding crop-mediated processes, such as the timing and magnitude of groundwater consumption by evapotranspiration (ET) and groundwater recharge, will be useful in management of groundwater, irrigated cropping systems, and surface water health. Previous modeling and field efforts have compared irrigated crop water use to a natural reference condition on a net annual basis. As a result, we presently understand that for irrigated potatoes and maize, the average annual ET is greater and therefore, the average annual recharge is less than rainfed row crops, grasslands, and both coniferous and deciduous forests. However, we have a limited understanding of the magnitude and timing of ET and recharge from irrigated cropping systems on shorter time scales that proceed with the annual cropping cycle (i.e. planting, full canopy, harvest, residue cover). We seek to understand the spatiotemporal variability of crop water budgets and associated water scarcity in the Wisconsin Central Sands through detailed measurements of drainage (potential

  7. Determination of Uranium, Thorium and Radium 226 in Zircon containig sands by alpha spectrometry

    International Nuclear Information System (INIS)

    Spezzano, P.

    1985-01-01

    The industrial utilization of Zircon sands for the production of refractories presents radiological problems owing to the risk of inhalation of Uranium, Thorium and their decay products, present in high concentrations in such materials. A method of analysis was realized for the determination of Uranium, Thorium and Radium-226 in Zircon sands, including the total dissolution of the sample, radiochemical separation and final measurement by alpha spectrometry with surface barrier detector. The concentrations of the main alpha-emitting radionuclides presents in two samples of Zircon sands have been determined and the possibility of disequilibrium along the decay series has been pointed out

  8. 2007 Lake County Board of County Commissioners Topographic LiDAR: Lake County, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This metadata document describes the LiDAR point data in LAS format produced by Kucera covering the project area of Lake County, FL. The data produced is...

  9. Local to regional scale industrial heavy metal pollution recorded in sediments of large freshwater lakes in central Europe (lakes Geneva and Lucerne) over the last centuries

    Energy Technology Data Exchange (ETDEWEB)

    Thevenon, Florian, E-mail: Florian.Thevenon@yahoo.fr [Institute F.-A. Forel, University of Geneva, Versoix (Switzerland); Graham, Neil D. [Institute F.-A. Forel, University of Geneva, Versoix (Switzerland); Chiaradia, Massimo [Department of Mineralogy, University of Geneva, Geneva (Switzerland); Arpagaus, Philippe; Wildi, Walter; Pote, John [Institute F.-A. Forel, University of Geneva, Versoix (Switzerland)

    2011-12-15

    This research first focuses on the spatial and temporal patterns of heavy metals from contrasting environments (highly polluted to deepwater sites) of Lake Geneva. The mercury (Hg) and lead (Pb) records from two deepwater sites show that the heavy metal variations before the industrial period are primarily linked to natural weathering input of trace elements. By opposition, the discharge of industrial treated wastewaters into Vidy Bay of Lake Geneva during the second part of the 20th century, involved the sedimentation of highly metal-contaminated sediments in the area surrounding the WWTP outlet pipe discharge. Eventually, a new Pb isotope record of sediments from Lake Lucerne identifies the long-term increasing anthropogenic lead pollution after ca. 1500, probably due to the development of metallurgical activities during the High Middle Ages. These data furthermore allows to compare the recent anthropogenic sources of water pollution from three of the largest freshwater lakes of Western Europe (lakes Geneva, Lucerne, and Constance). High increases in Pb and Hg highlight the regional impact of industrial pollution after ca. 1750-1850, and the decrease of metal pollution in the 1980s due to the effects of remediation strategies such as the implementation of wastewater treatment plants (WWTPs). However, at all the studied sites, the recent metal concentrations remain higher than pre-industrial levels. Moreover, the local scale pollution data reveal two highly contaminated sites (> 100 {mu}g Pb/g dry weight sediment) by industrial activities, during the late-19th and early-20th centuries (Lake Lucerne) and during the second part of the 20th century (Vidy Bay of Lake Geneva). Overall, the regional scale pollution history inferred from the three large and deep perialpine lakes points out at the pollution of water systems by heavy metals during the last two centuries due to the discharge of industrial effluents. Highlights: Black-Right-Pointing-Pointer Natural sources

  10. RADARSAT SAR data assessment of oil lakes in the Greater Burgan Oil Field, Kuwait

    International Nuclear Information System (INIS)

    Kwarteng, A. Y.; Al-Ajmi, D.; Singhroy, V.; Saint-Jean, R.

    1997-01-01

    RADARSAT images recorded in different beam modes were processed and used to assess the oil lakes in the Burgan oil field in Kuwait created by the fire setting of oil wells by the retreating Iraqi forces in the 1990-1991 Gulf War. The images were geometrically registered to each other and used as input to a change detection program. The main interest was to map and differentiate between the oil lakes, tarmats, vegetation, buried oil lakes, and also to evaluate the usefulness of RADARSAT's beam modes in characterizing such features. Results of the RADARSAT imagery analysis were compared to similar studies using optical and SIR-C/X-SAR data. Initially, there have approximately 300 oil lakes covering an area of about 49 sq km. Twenty-one million barrels of oil were recovered and exported; about one million barrels of unrecoverable oil was left in the oil fields. Since then most of the oil has evaporated, dried up to form tarmats, or has been covered by a veneer of sand and is no longer visible on the surface

  11. MECHANICAL REGENERATION OF SAND WASTE

    Directory of Open Access Journals (Sweden)

    D. I. Gnir

    2005-01-01

    Full Text Available The experimental activation of the sand regenerator of the firm SINTO is carried out at ОАО “MZOO". It is shown that sand grains are cleared from films of binding agents, that allows to use the treated sand for preparation of agglutinant and core sands.

  12. Molecular identification of a yellow perch viral disease associated with exposure to oil sands process affected waters

    International Nuclear Information System (INIS)

    Hogan, N.; Van den Heuvel, M.; Phalen, L.

    2010-01-01

    Large volumes of tailings and process affected water are generated as a result of oil sand mining processes. This presentation discussed the safe incorporation of these wastes into the terrestrial and aquatic landscape. A study was conducted in which yellow perch were stocked into experimental ponds, namely Demonstration Pond and South Bison Pond, during the periods of 1995-1997 and 2008-2010. Demonstration Pond was comprised of mature fine tailings capped with natural surface water, while South Bison Pond was formed at a site surrounded by overburden or lean oil sands. Disease surveys were conducted at these experimental ponds and also at Mildred, Sucker, and Kimowin Lakes. External white nodular lesions, characteristic of lymphocystis disease were observed on perch at all sites except Kimowin Lake. The identity of the virus was confirmed by DNA extraction and PCR with genotype generic major capsid protein gene primers. The presence of lymphocystis disease virus in perch was confirmed through sequencing of PCR results. The viral genotype appeared to be different from any previously isolated viral genotype. During the course of the study, there was an increasing incidence of the disease at Demonstration Pond and a decreasing incidence at the South Bison Pond. The intensity of the disease was found to be proportional to the incidence, which was positively correlated with changes in naphthenic acid concentration.

  13. Monitoring and optimization of thermal recovery wells at Nexen's Long Lake project

    Energy Technology Data Exchange (ETDEWEB)

    Furtado, S.; Howe, A.; Wozney, G.; Zaffar, S. [Nexen Inc. (Canada); Nelson, A. [Matrikon Inc. (Canada)

    2011-07-01

    The Long Lake project, operated by Nexen and situated in the Athabasca Oil Sands area in Alberta, Canada is a steam assisted gravity drainage scheme. In such thermal recovery processes, access to real time information is crucial. Nexen used specific tools to optimize monitoring in its Long Lake project and the aim of this paper is to present those customized well and facilities dashboards and reservoir trends. Real time and historical data on pressure, temperature injection and production rates are used in a Honeywell PHD Historian connected to a Delta-V DCS system to optimize recovery from the deposit. Results showed that these enhanced monitoring capabilities provided Nexen the ability to react rapidly to abnormal conditions, which resulted in significant financial benefits. The implementation of dashboard and reservoir trends in its Long Lake project helped Nexen to better monitor the reservoir and thus to optimize bitumen recovery.

  14. Assessing element-specific patterns of bioaccumulation across New England lakes

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Darren M.; Mayes, Brandon; Sturup, Stefan; Folt, Carol L.; Chen, Celia Y., E-mail: celia.chen@dartmouth.edu

    2012-04-01

    improve our capacity to identify consistent patterns of bioaccumulation and drivers of elevated trace element concentrations under naturally high levels of variability. - Highlights: Black-Right-Pointing-Pointer We assessed bioaccumulation of MeHg and 5 trace elements across trophic levels Black-Right-Pointing-Pointer Patterns were compared across multiple sample dates in 7 New England lakes Black-Right-Pointing-Pointer Each element had a unique pattern of bioaccumulation, consistent across lakes Black-Right-Pointing-Pointer Characterizing such patterns requires spatial and temporal replication in sampling.

  15. Crushed rock sand – An economical and ecological alternative to natural sand to optimize concrete mix

    Directory of Open Access Journals (Sweden)

    Sanjay Mundra

    2016-09-01

    Full Text Available The study investigates the use of crushed rock sand as viable alternative to Natural River sand that is being conventionally used as fine aggregate in cement concrete. Various mix designs were developed for different grades of concrete based on IS, ACI and British codes using Natural River sand and crushed rock sand. In each case, the cube compressive strength test, and beam flexure tests were conducted. The results of the study show that, the strength properties of concrete using crushed rock sand are nearly similar to the conventional concrete. The study has shown that crushed stone sand can be used as economic and readily available alternative to river sand and can therefore help to arrest the detrimental effects on the environment caused due to excessive mining of river sand.

  16. Evaluation of Water Quality in Shallow Lakes, Case Study of Lake Uluabat

    Directory of Open Access Journals (Sweden)

    Saadet İLERİ

    2014-04-01

    Full Text Available Lake Uluabat, located 20 km south of the Marmara Sea, between 42° 12' North latitude, 28° 40'East longitude and is located in the province of Bursa. The Lake is one of the richest lakes in terms of aquatic plants besides fish and bird populations in Turkey. In this study, water quality of the Lake was monitored from June 2008 to May 2009 during the 12 month period with the samples taken from 8 points in the lake and spatial and temporal variations of the parameters were examined. pH, temperature (T, electrical conductivity (EC, dissolved oxygen (DO, suspended solids (SS, secchi depth (SD, water level (WL, nitrate nitrogen (NO3-N, total nitrogen (TN, phosphate-phosphorus (PO4-P, total phosphorus (TP, alkalinity, chemical oxygen demand (COD and chlorophyll-a (Chl-a were the monitoring parameters. As a result, concentrations of the parameters were found at high levels especially the 1st, 4th, 5th, and 8th stations and temporally were found at high levels often in the summer. According to the results of analysis of variance, regional and temporal variations of all parameters were found important except SS and NO3-N

  17. High-mountain lakes provide a seasonal niche for migrant American dippers

    Science.gov (United States)

    J. M. Garwood; K. L. Pope; R. M. Bourque; M. D. Larson

    2009-01-01

    We studied summer use of high elevation lakes by American Dippers (Cinclus mexicanus) in the Trinity Alps Wilderness, California by conducting repeated point-count surveys at 16 study lakes coupled with a 5-year detailed survey of all available aquatic habitats in a single basin. We observed American Dippers during 36% of the point-count surveys...

  18. Rheological Characterization of Green Sand Flow

    DEFF Research Database (Denmark)

    Jabbaribehnam, Mirmasoud; Spangenberg, Jon; Hovad, Emil

    2016-01-01

    The main aim of this paper is to characterize experimentally the flow behaviour of the green sand that is used for casting of sand moulds. After the sand casting process is performed, the sand moulds are used for metal castings. The rheological properties of the green sand is important to quantif...

  19. Global relationships between phosphorus and chlorophyll-a in oxbow lakes

    Science.gov (United States)

    Belcon, A. U.; Bernhardt, E. S.; Fritz, S. C.; Baker, P. A.

    2011-12-01

    Traditional limnological studies have focused on extant, large and deep bodies of fresh water. For over 70 years a strong positive relationship between sestonic chlorophyll-a (Chl-a) and total phosphorus (TP) has been established in temperate lakes with phosphorus generally viewed as the most limiting factor to productivity (Deevey 1940, Schindler 1977). Over the last few decades however, investigations have expanded to include the examination of shallow lakes, particularly in terms of water quality, nutrient content and regime shifts between stable alternate states. Most of these studies, however, have focused on northern, high latitude regions where the lakes are typically postglacial, isolated and fed by small streams. Relatively little work has been done on oxbow lakes which are floodplain lakes and are semi or permanently connected to the river. Oxbow lakes have been shown to serve several important ecologic and economic functions including nurseries for young fish, feeding grounds for top aquatic predators and increasing the biodiversity of the landscape particularly in tropical regions of the world where high precipitation and large rivers have produced thousands of oxbow lakes. In many developing countries oxbow lakes are an important source of revenue through fishing. This study examined the relationship between nutrients and productivity in oxbow lakes globally through a wide-spread literature synthesis. Four hundred and twenty nine oxbow lakes were represented by 205 data points while 285 data points represented 156 non-floodplain lakes. Despite differences in latitude, lake size and climate we find that oxbow lakes globally have a significantly less steep slope in their TP/Chl relationship than non-floodplain lakes do indicating that the same amount of sestonic phosphorus results in lower productivity. Oxbow lakes (TP/Chl): r = 0.7676, slope = 0.7257, Non-floodplain lakes (TP/Chl): r = 0.8096, slope = 1.1309. We theorize that their connection to the

  20. Modern processes of sediment formation in Lake Towuti, Indonesia, as derived from the composition of lake surface sediments

    Science.gov (United States)

    Hasberg, Ascelina; Melles, Martin; Morlock, Marina; Vogel, Hendrik; Russel, James M.; Bijaksana, Satria

    2016-04-01

    In summer 2015, a drilling operation funded by the International Continental Scientific Drilling Program (ICDP) was conducted at Lake Towuti (2.75°S, 121.5°E), the largest tectonically formed lake (surface area: 561 km²) of the Republic Indonesia. The Towuti Drilling Project (TDP) recovered more than 1000 meters of sediment core from three sites. At all three sites replicate cores down to 133, 154, and 174 m below lake floor have penetrated the entire lake sediment record, which is expected to comprise the past ca. 650.000 years continuously. Lake Towutís sediment record thus can provide unique information for instance concerning the climatic and environmental history in the Indo-Pacific-Warm-Pool (IPWP) and concerning the evolutionary biology in SE Asia. For a better understanding of the palaeoenvironmental proxies to be analyzed on the drill cores, the modern processes of sediment formation in the lake and in its catchment - under known environmental conditions - were investigated on a set of 84 lake sediment surface samples. Sampling was conducted by grab sampler (UWITEC Corp., Austria) in a grid of 1 to 4 km resolution that covers the entire lake. The samples were analyzed for inorganic geochemical composition (XRF powder scans and ICP-MS), magnetic susceptibility (Kappabridge), grain-size distribution (laser scanner), biogenic components (smear-slide analyses), biogenic silica contents (leaching), and carbonate, total organic carbon (TOC), nitrogen (TN), and sulfur (TS) concentrations (elemental analyzer). The sediments close to the lake shores and in front of the major river inlets are characterized by mean grain sizes coarser than average and high magnetic susceptibilities presented by high ratios of Cr, Ni, Co, and Zr. This reflects higher energies due to wave action and fluvial sediment supply, as well as the occurrence of magnetic minerals particularly in the sand and gravel fractions of the sediments. In regions of deeper waters and more distal to

  1. Investigations of the Influence of the Matrix Recycling on Properties of the Moulding Sand with Geopol 618 Binder

    Directory of Open Access Journals (Sweden)

    J. Kamińska

    2013-01-01

    Full Text Available Self-hardening moulding sands with water-glass hardened by liquid esters are applied in several foundry plants for making moulds for the production of heavy iron and steel castings. The main good point of this process is a low cost of sands. However, on account of a lowsusceptibility of this moulding sand for the matrix reclamation the fraction of sands originated from the reclamation is limited.The investigations presented in this work were aimed at the determination of the addition of the reclaimed material, obtained in the dry mechanical reclamation, on properties of the moulding sand with the Geopol 618 binder, which is water-glass modified by polymers and hardened by esters.

  2. Investigations of the Influence of the Matrix Recycling on Properties of the Moulding Sand with Geopol 618 Binder

    Directory of Open Access Journals (Sweden)

    Kamińska J.

    2013-03-01

    Full Text Available Self-hardening moulding sands with water-glass hardened by liquid esters are applied in several foundry plants for making moulds for the production of heavy iron and steel castings. The main good point of this process is a low cost of sands. However, on account of a low susceptibility of this moulding sand for the matrix reclamation the fraction of sands originated from the reclamation is limited. The investigations presented in this work were aimed at the determination of the addition of the reclaimed material, obtained in the dry mechanical reclamation, on properties of the moulding sand with the Geopol 618 binder, which is water-glass modified by polymers and hardened by esters.

  3. Juliana Lake: A Benghazi Wetland In Distress!

    Science.gov (United States)

    Abdulsamad, Esam O.; Elbabour, Mansour M.

    2013-04-01

    Of all the remaining natural habitats of Benghazi's urban area (NE Libya), perhaps the most threatened are its karst lakes and coastal salt marshes (locally known as Sebkhas). Juliana Lake stands out as one example of a fragile ecosystem that is steadily shrinking and exposed to dredging and, consequently, possible damage to its aquatic organisms, and the inevitable loss of its renowned biodiversity. Several 19th & 20th-century traveler's sketches and maps, soil maps, photographs and satellite images provide the bases for change in the size and magnitude of the lake and its adjacent areas over time. The study also includes an assessment of the sediment composition and texture of material accumulating at the bottom of the lake. These sediments are composed essentiality of mixtures of Sebkha sediments such as salty clay, silt, and clayey sand. The sediments at the surface and around the Juliana Lake, however, are represented by quite soft whitish to yellowish and scattered patchy limestones of unknown affinity. Terra-rossa (reddish soil) and Quaternary caliche are present also but calcarenites (clastic limestone) cover considerable part of the studied area. The bio-micro components of these sediments are described and a number of small-sized benthic foraminifera have been identified. Macrofauna, which are primarily presented by recent benthic seashells belonging to phylum mollusca, have also been investigated and several species have been identified to the species level wherever possible. Other calcareous biotic components are predominantly shell fragments of molluscs, bryozoans, echinoderms and calcareous coralline red algae. It is concluded that the distribution, diversity and abundance of the total benthic organisms recovered in this survey reflect that the local habitat of the Juliana Lake were rich in nutrients and consequently providing an important food source for fishes, birds, and mammals. In fact, without these benthic organisms, these larger animals would

  4. Rabbit Lake uranium mining a-zone, d-zone, eagle point: report of the environmental assessment panel

    International Nuclear Information System (INIS)

    1993-11-01

    A report of the environmental assessment panel on Rabbit Lake, Saskatchewan. A review of the proposed development of the uranium mining facility at Rabbit Lake with respect to the environmental, health, safety, and socioeconomic impacts

  5. Rabbit Lake uranium mining a-zone, d-zone, eagle point: report of the environmental assessment panel

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-11-01

    A report of the environmental assessment panel on Rabbit Lake, Saskatchewan. A review of the proposed development of the uranium mining facility at Rabbit Lake with respect to the environmental, health, safety, and socioeconomic impacts.

  6. Geophysical and hydrologic studies of lake seepage variability

    Science.gov (United States)

    Toran, Laura; Nyquist, Jonathan E.; Rosenberry, Donald O.; Gagliano, Michael P.; Mitchell, Natasha; Mikochik, James

    2014-01-01

    Variations in lake seepage were studied along a 130 m shoreline of Mirror Lake NH. Seepage was downward from the lake to groundwater; rates measured from 28 seepage meters varied from 0 to −282 cm/d. Causes of this variation were investigated using electrical resistivity surveys and lakebed sediment characterization. Two-dimensional (2D) resistivity surveys showed a transition in lakebed sediments from outwash to till that correlated with high- and low-seepage zones, respectively. However, the 2D survey was not able to predict smaller scale variations within these facies. In the outwash, fast seepage was associated with permeability variations in a thin (2 cm) layer of sediments at the top of the lakebed. In the till, where seepage was slower than that in the outwash, a three-dimensional resistivity survey mapped a point of high seepage associated with heterogeneity (lower resistivity and likely higher permeability). Points of focused flow across the sediment–water interface are difficult to detect and can transmit a large percentage of total exchange. Using a series of electrical resistivity geophysical methods in combination with hydrologic data to locate heterogeneities that affect seepage rates can help guide seepage meter placement. Improving our understanding of the causes and types of heterogeneity in lake seepage will provide better data for lake budgets and prediction of mass transfer of solutes or contaminants between lakes and groundwater.

  7. Community structure and decadal changes in macrozoobenthic assemblages in Lake Poyang, the largest freshwater lake in China

    Directory of Open Access Journals (Sweden)

    Cai Y. J.

    2014-01-01

    Full Text Available Lake Poyang is the largest freshwater lake in China and contains unique and diverse biota within the Yangtze floodplain ecosystem. However, knowledge of its macrozoobenthic assemblages remains inadequate. To characterize the current community structure of these assemblages and to portray their decadal changes, quarterly investigations were conducted at 15 sites from February to November 2012. A total of 42 taxa were recorded, and Corbicula fluminea, Limnoperna fortunei, Gammaridae sp., Nephtys polybranchia, Polypedilum scalaenum and Branchiura sowerbyi were found to dominate the community in terms of abundance. The bivalves Corbicula fluminea, Lamprotula rochechouarti, Arconaia lanceolata and Lamprotula caveata dominated the community in biomass due to their large body size. The mean abundance of the total macrozoobenthos varied from 48 to 920 ind·m-2, the mean biomass ranged from 28 to 428 g·m-2. The substrate type affected strongly the abundance, biomass, and diversity of the macrozoobenthos, with muddy sand substrates showing the highest values. Compared with historical data, remarkable changes were observed in the abundance of macrozoobenthos and the identity of the dominant species. The mean total abundance decreased from 724 ind·m-2 in 1992 to 228 ind·m-2 in 2012. The dominant species have shifted dramatically. Large unionids were dominant before 1998, whereas pollution-tolerant species (e.g., Branchiura sowerbyi increased in dominance after 2008. Our findings should have implications for the conservation of the benthic biodiversity of this large Yangtze-connected lake.

  8. The Alberta oil sands story

    Energy Technology Data Exchange (ETDEWEB)

    1974-01-01

    This report serves as a detailed introduction to the Alberta oil sands and their development. It includes a description of the oil sands deposits, an outline of crude bitumen recovery and upgrading processes, the role of Alberta Energy Company in oil sands development, environmental aspects, manpower requirements for oil sands development, research needs, and further oil sands projects. Presently proven recoverable reserves in the oil sands amount to 26.5 billion bbl of synthetic crude. Production from the Syncrude plant (125,000 bbl/d capacity) is expected to begin in 1977, followed by a Shell Canada operation around 1980. The provincial government will participate in the oil sand industry through its joint venture participation in Syncrude and its 50% share in Alberta Energy Company; the latter company participates in related aspects of the Syncrude project, such as pipelines. The result of Alberta's participation in the industry will mean that, directly or indirectly, the province will realize 60% of the total profits. The job creation potential of oil sands projects is estimated to be extensive, with a direct and indirect work force supported by oil sands activities possibly reaching 180,000 persons by the year 2000. Research needs have been identified, particularly in the area of in-situ thermal recovery technology, and the creation of the Alberta Oil Sands Technology and Research Authority has been authorized in order to meet these needs. Although current reserves are sufficient to support 20-30 synthetic crude plants, a number of factors will limit expansion of the industry. 8 figs., 5 tabs.

  9. Great Lakes

    Science.gov (United States)

    Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    population.The wild plants and animals and the natural systems that support them in the Great Lakes region are valuable resources of considerable local, regional, and national interest. They are also, in part, transboundary resources that we share with our Canadian neighbors to the north. The way these resources are changing over time is inadequately known and is a cause for concern for resource users and for those charged with managing and protecting these unique and valuable resources. This chapter describes the wild plants and animals and the systems that support them in the Great Lakes region; addresses their condition; and points out the gaps in our knowledge about them that, if filled, would aid in their conservation and appropriate use.

  10. The immune response to sand fly salivary proteins and its influence on Leishmania immunity

    Directory of Open Access Journals (Sweden)

    Regis eGomes

    2012-05-01

    Full Text Available Leishmaniasis is a vector-borne disease transmitted by bites of phlebotomine sand flies. During Leishmania transmission, sand fly saliva is co-inoculated with parasites into the skin of the mammalian host. Sand fly saliva consists of roughly thirty different salivary proteins, many with known roles linked to blood feeding facilitation. Apart from the anti-hemostatic capacity of saliva, several sand fly salivary proteins have been shown to be immunogenic upon multiple contacts with a mammalian host. Immunization with single immunogenic salivary proteins or exposure to uninfected bites can produce protective immune responses against leishmaniasis. These sand fly salivary proteins induce cellular immune responses and/or antibodies. Antibodies to saliva are not required for protection in a mouse model against leishmaniasis. A strong body of evidence points to the role for saliva-specific T cells producing IFN-γ in the form of a delayed-type hypersensitivity reaction at the bite site as the main protective response. Herein, we review immunity to sand fly salivary proteins in the context of its vector-parasite-host combinations and vaccine potential, as well as some recent advances to shed light on the mechanism of how an immune response to sand fly saliva protects against leishmaniasis.

  11. Distribution of 137Cs and 226Ra in the sediments of Aswan High Dam lake

    International Nuclear Information System (INIS)

    Ismail, S.S.; Unfried, E.; Grass, F.

    1994-01-01

    Sediment samples of the High Dam lake were investigated for their 137 Cs, 226 Ra, 228 Th, and 40 K content, using low-level γ-spectroscopy. The results show that at the beginning of the lake (500 km from the High Dam), where sediments consist mostly of sand, the level of 137 Cs is very low (0.1 Bq*kg -1 ). The maximum value (22.3 Bq*kg -1 ) was found 40 km from the wall of the High Dam, where the composition of the sediments is nearly 50% clays. The distribution of the natural nuclides 226 Ra, 228 Th and 40 K shows a different trend. (author) 9 refs.; 9 figs.; 1 tab

  12. Identifying non-point sources of endocrine active compounds and their biological impacts in freshwater lakes

    Science.gov (United States)

    Baker, Beth H.; Martinovic-Weigelt, Dalma; Ferrey, Mark L.; Barber, Larry B.; Writer, Jeffrey H.; Rosenberry, Donald O.; Kiesling, Richard L.; Lundy, James R.; Schoenfuss, Heiko L.

    2014-01-01

    Contaminants of emerging concern, particularly endocrine active compounds (EACs), have been identified as a threat to aquatic wildlife. However, little is known about the impact of EACs on lakes through groundwater from onsite wastewater treatment systems (OWTS). This study aims to identify specific contributions of OWTS to Sullivan Lake, Minnesota, USA. Lake hydrology, water chemistry, caged bluegill sunfish (Lepomis macrochirus), and larval fathead minnow (Pimephales promelas) exposures were used to assess whether EACs entered the lake through OWTS inflow and the resultant biological impact on fish. Study areas included two OWTS-influenced near-shore sites with native bluegill spawning habitats and two in-lake control sites without nearby EAC sources. Caged bluegill sunfish were analyzed for plasma vitellogenin concentrations, organosomatic indices, and histological pathologies. Surface and porewater was collected from each site and analyzed for EACs. Porewater was also collected for laboratory exposure of larval fathead minnow, before analysis of predator escape performance and gene expression profiles. Chemical analysis showed EACs present at low concentrations at each study site, whereas discrete variations were reported between sites and between summer and fall samplings. Body condition index and liver vacuolization of sunfish were found to differ among study sites as did gene expression in exposed larval fathead minnows. Interestingly, biological exposure data and water chemistry did not match. Therefore, although results highlight the potential impacts of seepage from OWTS, further investigation of mixture effects and life history factor as well as chemical fate is warranted.

  13. Late Quaternary sedimentary features of Bear Lake, Utah and Idaho

    Science.gov (United States)

    Smoot, J.P.

    2009-01-01

    Bear Lake sediments were predominantly aragonite for most of the Holocene, reflecting a hydrologically closed lake fed by groundwater and small streams. During the late Pleistocene, the Bear River flowed into Bear Lake and the lake waters spilled back into the Bear River drainage. At that time, sediment deposition was dominated by siliciclastic sediment and calcite. Lake-level fluctuation during the Holocene and late Pleistocene produced three types of aragonite deposits in the central lake area that are differentiated primarily by grain size, sorting, and diatom assemblage. Lake-margin deposits during this period consisted of sandy deposits including well-developed shoreface deposits on margins adjacent to relatively steep gradient lake floors and thin, graded shell gravel on margins adjacent to very low gradient lake-floor areas. Throughout the period of aragonite deposition, episodic drops in lake level resulted in erosion of shallow-water deposits, which were redeposited into the deeper lake. These sediment-focusing episodes are recognized by mixing of different mineralogies and crystal habits and mixing of a range of diatom fauna into poorly sorted mud layers. Lake-level drops are also indicated by erosional gaps in the shallow-water records and the occurrence of shoreline deposits in areas now covered by as much as 30 m of water. Calcite precipitation occurred for a short interval of time during the Holocene in response to an influx of Bear River water ca. 8 ka. The Pleistocene sedimentary record of Bear Lake until ca. 18 ka is dominated by siliciclastic glacial fl our derived from glaciers in the Uinta Mountains. The Bear Lake deep-water siliciclastic deposits are thoroughly bioturbated, whereas shallow-water deposits transitional to deltas in the northern part of the basin are upward-coarsening sequences of laminated mud, silt, and sand. A major drop in lake level occurred ca. 18 ka, resulting in subaerial exposure of the lake floor in areas now covered by

  14. Nitrogen Dynamics Variation in Overlying Water of Jinshan Lake, China

    Directory of Open Access Journals (Sweden)

    Xiaohong Zhou

    2015-01-01

    Full Text Available Jinshan Lake is a famous urban landscape lake with approximately 8.8 km2 water area, which is located on the north of Zhenjiang, of Jiangsu Province, China. Eighteen sampled sites were selected and overlying water was sampled from 2013 to 2014 to study the seasonal and spatial variation of nitrogen in overlying water of Jinshan Lake. Results showed that physicochemical characteristics of temperature, pH, and DO showed high seasonal variation, whereas they had no significant spatial differences in the 18 sampling points (P>0.05 in overlying water of Jinshan Lake. Nitrogen concentrations showed strong seasonal variation trends. The ranked order of TN was as follows: spring > summer > autumn > winter; the order of NH4+-N was as follows: spring > autumn > summer > winter, whereas NO3--N concentrations revealed an inverse seasonal pattern, with maxima occurring in winter and minimal values occurring in spring. Nitrogen concentrations had dramatic spatial changes in 18 sampling points of Jinshan Lake. Physicochemical parameter difference, domestic wastes pollution, and rainfall runoff source may have led to seasonal and spatial fluctuation variations of nitrogen in overlying water of Jinshan Lake, China.

  15. Lake Whitney Comprehensive Water Quality Assessment, Phase 1B- Physical and Biological Assessment (USDOE)

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Robert D; Byars, Bruce W

    2009-11-24

    Baylor University Center for Reservoir and Aquatic Systems Research (CRASR) has conducted a phased, comprehensive evaluation of Lake Whitney to determine its suitability for use as a regional water supply reservoir. The area along the Interstate 35 corridor between Dallas / Fort Worth Metroplex and the Waco / Temple Centroplex represents one of the fastest growth areas in the State of Texas and reliable water supplies are critical to sustainable growth. Lake Whitney is situated midway between these two metropolitan areas. Currently, the City of Whitney as well as all of Bosque and Hill counties obtain their potable water from the Trinity Sands aquifer. Additionally, parts of the adjoining McLennan and Burleson counties utilize the Trinity sands aquifer system as a supplement to their surface water supplies. Population growth coupled with increasing demands on this aquifer system in both the Metroplex and Centroplex have resulted in a rapid depletion of groundwater in these rural areas. The Lake Whitney reservoir represents both a potentially local and regional solution for an area experiencing high levels of growth. Because of the large scope of this project as well as the local, regional and national implications, we have designed a multifaceted approach that will lead to the solution of numerous issues related to the feasibility of using Lake Whitney as a water resource to the region. Phase IA (USEPA, QAPP Study Elements 1-4) of this research focused on the physical limnology of the reservoir (bathymetry and fine scale salinity determination) and develops hydrodynamic watershed and reservoir models to evaluate how salinity would be expected to change with varying hydrologic and climatic factors. To this end, we implemented a basic water quality modeling program in collaboration with the Texas Parks and Wildlife Department and the Texas Commission on Environmental Quality to add to the developing long-term database on Lake Whitney. Finally, we conducted an initial

  16. Compressive behavior of fine sand.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Bradley E. (Air Force Research Laboratory, Eglin, FL); Kabir, Md. E. (Purdue University, West Lafayette, IN); Song, Bo; Chen, Wayne (Purdue University, West Lafayette, IN)

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  17. Yellow perch embryo-larval survival and growth in surface waters associated with oil-sands mining

    International Nuclear Information System (INIS)

    Peters, L.E.; Heuvel, M.R. van den; Dixon, D.G.; Power, M.; Boerger, H.; MacKinnon, M.D.; Meer, T. Van

    1995-01-01

    As part of their land reclamation strategy, Syncrude Canada Ltd. is currently developing environmentally acceptable tailings disposal methods. Fine tailings, a suspension of clay and residual bitumen, is the waste product from oil sands extraction. Fine-tailings contain naphthenic acids, a group of saturated aliphatic and alicyclic carboxylic acids, which occur naturally in petroleum and are partly responsible for the toxicity of process water. The wet landscape method involves covering fine tails with a layer of water such that a self-sustaining ecosystem can be established. A 5 ha demonstration pond with a bottom of fine-tailings was constructed and stocked with yellow perch for experimental purposes. Two other reclaimed ponds formed with oil-sands overburden material were also stocked with perch. Adult perch sampled in the fall of 1995 from the experimental and reclaimed ponds exhibited a 2-fold induction of MFO activity compared to the source lake; indicating organic compound exposure. Perch from one of the reclaimed ponds showed significantly reduced circulating reproductive hormone levels, gonad size and smaller ovarian follicles. Reproductive parameters were not different between the source lake and the remaining ponds. Paired lab and field experiments were conducted to determine if contaminants present would be detrimental to egg viability and development of larvae either through direct exposure of spawned eggs or indirectly by effecting oogenesis. An early life stage toxicity test was also performed using commercially available naphthenic acid standard. Endpoints measured were percent fertilization, percent hatch, mortality, deformities, timing of developmental periods and larval growth

  18. Treating cooling pond water for Wabamun Lake level mitigation project in Alberta

    International Nuclear Information System (INIS)

    Anon

    2004-01-01

    Dealing with the challenge of recharging Wabamun Lake by treating nearby cooling pond water, fed by the North Saskatchewan River, and returning it to the lake, is discussed. To deal with the problem, TransAlta Utilities constructed a treatment plant in 1997 next to the 2,029 MW Sundance power plant to mitigate the effect the power plant's ongoing and historical effect on the lake's water level. The objective of the treatment plant is to treat cooling pond water and return it to the lake to raise water levels there, which have been significantly reduced over the last 25 years mostly by power plant intake, but also by lack of rainfall, surface runoff, and natural evaporation. At the Treatment Facility the water to be treated is first chlorinated to kill zooplankton, algae and bacteria, followed by adjusting the pH using sulfuric acid. Alum coagulant is used to destabilize colour, particles and colloids. The next step is feeding the water to the Actiflo clarifiers which use microsand to provide increased surface area for floc attachment, and to act as ballast. Clarified water from the Actiflo system is then fed to to the Dusenflo filters to remove the largest particles of suspended solids, and through a finer sand media to remove the remaining turbidity, colour and bacteria. Thiosulfate is used in the ozonation system to inactivate any remaining bacteria and zooplankton in the filtered water, before discharging it to the lake. The cooling towers, which are part of the system, ensure that the treated water returned to the lake is kept at a constant temperature, varying no more than three degrees C from the lake water temperature. 3 figs

  19. LIMNOLOGY, LAKE BASINS, LAKE WATERS

    Directory of Open Access Journals (Sweden)

    Petre GÂŞTESCU

    2009-06-01

    Full Text Available Limnology is a border discipline between geography, hydrology and biology, and is also closely connected with other sciences, from it borrows research methods. Physical limnology (the geography of lakes, studies lake biotopes, and biological limnology (the biology of lakes, studies lake biocoenoses. The father of limnology is the Swiss scientist F.A. Forel, the author of a three-volume entitled Le Leman: monographie limnologique (1892-1904, which focuses on the geology physics, chemistry and biology of lakes. He was also author of the first textbook of limnology, Handbuch der Seenkunde: allgemeine Limnologie,(1901. Since both the lake biotope and its biohydrocoenosis make up a single whole, the lake and lakes, respectively, represent the most typical systems in nature. They could be called limnosystems (lacustrine ecosystems, a microcosm in itself, as the American biologist St.A. Forbes put it (1887.

  20. Investigating changes in land use cover and associated environmental parameters in Taihu Lake in recent decades using remote sensing and geochemistry.

    Directory of Open Access Journals (Sweden)

    Changchun Huang

    Full Text Available Humans have had a significant impact on the terrestrial pedosphere through activities such as agriculture and urbanization. The effects of human activities on land use and the related environmental changes were investigated through point and areal studies surrounding Meiliang Bay, which is an open area of extreme eutrophication in Taihu Lake, China. This study used remote sensing and environmental-tracer profiles [total nitrogen (TN, total phosphorus (TP, total organic carbon (TOC, grain size, and geochemical parameters] to determine the causes of changes in land use and the associated environmental parameters. The results of LUCCs (Land use/cover changes indicate that over the past three decades, total farmland decreased by 862.49 km2, with an annual decrement rate of 28.75 km2/year, and total urbanized land increased by 859.71 km2, with an annual growth rate of 28.66 km2/year. The geochemical results indicate that the trophic state of Taihu Lake was persistently intensifying and that the TN, TP, and TOC concentrations increased twofold, threefold, and twofold, respectively, from 1949 to 2010. The sources of TN, TP, and TOC were highly similar after 1975. However, before 1974, TN and TP originated from different sources than TOC. The grassland and woodland around the lake retain nutrients and sand from the land of study area. The increase in urbanized land and tertiary industries significantly increased the sediment concentrations of TN, TP, and TOC after 1980.

  1. Integrated oil sands tailings pond water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Z. [Saskatchewan Research Council, Saskatoon, SK (Canada)

    2010-07-01

    This PowerPoint presentation discussed research currently being conducted to treat oil sands tailings pond water (TPW). The treatment of TPW is challenged by the high level of naphthenic acids (NAs), the slow settling rate of fine particulate materials, and the complex chemistry of the water. The treatment process consisted of bioflocculation, sludge blanket assisted clarification, ozonation, and oil sands coke assisted hybrid biodegradation. The aggregation and adsorption process bound small particles and cells together while also ensuring the passive uptake of pollutants using microbial masses. The mixed liquor then passed through a sludge blanket to ensure enhanced particle capture. An ozonation process was used to increase the biodegradability of the TPW as well as to increase the biodegradability of the residual NAs after ozonation. The process used a hybrid bioreactor that consisted of both suspended and fixed microbial communities. The coke served as a biofilm carrier for the waste. Further studies are being conducted to investigate the efficiency and capability of the process. tabs., figs.

  2. Characteristics of the summit lakes of Ambae volcano and their potential for generating lahars

    Directory of Open Access Journals (Sweden)

    P. Bani

    2009-08-01

    Full Text Available Volcanic eruptions through crater lakes often generate lahars, causing loss of life and property. On Ambae volcano, recent eruptive activities have rather tended to reduce the water volume in the crater lake (Lake Voui, in turn, reducing the chances for outburst floods. Lake Voui occupies a central position in the summit caldera and is well enclosed by the caldera relief. Eruptions with significantly higher magnitude than that of 1995 and 2005 are required for an outburst. A more probable scenario for lahar events is the overflow from Lake Manaro Lakua bounded on the eastern side by the caldera wall. Morphology and bathymetry analysis have been used to identify the weakest point of the caldera rim from which water from Lake Manaro Lakua may overflow to initiate lahars. The 1916 disaster described on south-east Ambae was possibly triggered by such an outburst from Lake Manaro Lakua. Taking into account the current level of Lake Manaro Lakua well below a critical overflow point, and the apparently low potential of Lake Voui eruptions to trigger lahars, the Ambae summit lakes may not be directly responsible for numerous lahar deposits identified around the Island.

  3. Land cover mapping at Alkali Flat and Lake Lucero, White Sands, New Mexico, USA using multi-temporal and multi-spectral remote sensing data

    Science.gov (United States)

    Ghrefat, Habes A.; Goodell, Philip C.

    2011-08-01

    The goal of this research is to map land cover patterns and to detect changes that occurred at Alkali Flat and Lake Lucero, White Sands using multispectral Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Advanced Land Imager (ALI), and hyperspectral Hyperion and Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data. The other objectives of this study were: (1) to evaluate the information dimensionality limits of Landsat 7 ETM+, ASTER, ALI, Hyperion, and AVIRIS data with respect to signal-to-noise and spectral resolution, (2) to determine the spatial distribution and fractional abundances of land cover endmembers, and (3) to check ground correspondence with satellite data. A better understanding of the spatial and spectral resolution of these sensors, optimum spectral bands and their information contents, appropriate image processing methods, spectral signatures of land cover classes, and atmospheric effects are needed to our ability to detect and map minerals from space. Image spectra were validated using samples collected from various localities across Alkali Flat and Lake Lucero. These samples were measured in the laboratory using VNIR-SWIR (0.4-2.5 μm) spectra and X-ray Diffraction (XRD) method. Dry gypsum deposits, wet gypsum deposits, standing water, green vegetation, and clastic alluvial sediments dominated by mixtures of ferric iron (ferricrete) and calcite were identified in the study area using Minimum Noise Fraction (MNF), Pixel Purity Index (PPI), and n-D Visualization. The results of MNF confirm that AVIRIS and Hyperion data have higher information dimensionality thresholds exceeding the number of available bands of Landsat 7 ETM+, ASTER, and ALI data. ASTER and ALI data can be a reasonable alternative to AVIRIS and Hyperion data for the purpose of monitoring land cover, hydrology and sedimentation in the basin. The spectral unmixing analysis and dimensionality eigen

  4. On Pluvial Compaction of Sand

    DEFF Research Database (Denmark)

    Jacobsen, Moust

    At the Institute of Civil Engineering in Aalborg model tests on dry sand specimens have been carried out during the last five years. To reduce deviations in test results, the sand laying technique has been carefully studied, and the sand mass spreader constructed. Preliminary results have been...

  5. MORPHOMETRIC CHARACTERIZATION OF THE SAND FRACTION IN A SAND GRAIN IMAGE CAPTURE SYSTEM1

    Directory of Open Access Journals (Sweden)

    Lucimar Arruda Viana

    Full Text Available ABSTRACT Morphology studies assume significant importance in analysis of phenomena of granular systems packaging, in particular with a view to the use of the technique of soil stabilization named particle size correction in forest roads. In this context, this study aimed to develop and operationalize a Sand Grain Image Capture System and, hereby, determine the morphological indices of the sand fractions of two sandy soils called João Pinheiro (JP and Cachoeira da Prata (CP. Soil samples, air-dried, were sieved (2.0 mm nominal mesh size for removal of gravels. The materials that passed through the sieve were subjected to dispersion, washing in 0.053 mm nominal mesh size sieve, removal of organic matter and iron oxides to obtain the clean sand fractions. Subsequently, each soil sample was sieved for separation into twelve classes, between the diameters of 0.149 mm and 1.190 mm, using a Rotap shaker. Next, tests were carried out to characterize the morphometric attributes of the twelve classes of sand fractions of the soils studied. For validation of the performance of the Sand Grain Image Capture System, the results were compared to those obtained using a standard procedure for image analysis. The analysis of the results led to the following conclusions: (i the sand fraction of the JP soil presented higher values for the morphometric indices roundness, elongation and compactness compared to sand fraction of the CP soil; and (ii the Sand Grain Image Capture System worked properly, with practicality.

  6. Dispersal and memory of sand flies in an endemic area of cutaneous leishmaniasis, southern Brazil.

    Science.gov (United States)

    Silva, Natália Maria Maciel Guerra; De Melo, Simone Cristina Castanho Sabaini; Massafera, Rubens; Rossi, Robson Marcelo; Silveira, Thaís Gomes Verzignassi; Teodoro, Ueslei

    2013-09-01

    The dispersal of and the existence of memory in sand flies were measured in a transmission area of cutaneous leishmaniasis, in the municipality of Bandeirantes, Paraná, Brazil. Sand flies were caught in a rural area, with Shannon trap installed in the forest and three Falcão traps installed in a human-inhabited environment (HIE) and three others in an impacted environment presently uninhabited by humans (EUH), from 1800 to 0600 hours. The captured sand flies were marked with yellow, blue, or red fluorescent powder, according to the environments where they were captured. All marked sand flies were released at 0700 hours at a point between the three environments. The recaptures were made with 28 Falcão traps, distributed in the environments from for 10 consecutive days. The sand flies recaptured were examined under a stereomicroscope and later identified. It was concluded that sand flies are able to disperse over an average distance of 73 m, reaching 130 m in 24 h, showing that: 1) the sand flies were attracted with different intensities to each environment, and the ability to move among different environments allows the existence of enzootic cycle of Leishmania; 2) the sand flies possess a spatial memory, olfactory memory, or both, that enable them to return to the environment where they were captured initially, although the distances were different.

  7. Water quality management for Lake Mariout

    Directory of Open Access Journals (Sweden)

    N. Donia

    2016-06-01

    Full Text Available A hydrodynamic and water quality model was used to study the current status of the Lake Mariout subject to the pollution loadings from the agricultural drains and the point sources discharging directly to the Lake. The basic water quality modelling component simulates the main water quality parameters including the oxygen compounds (BOD, COD, DO, nutrients compounds (NH4, TN, TP, and finally the temperature, salinity and inorganic matter. Many scenarios have been conducted to improve the circulation and the water quality in the lake and to assess the spreading and mixing of the discharge effluents and its impact on the water quality of the main basin. Several pilot interventions were applied through the model in the Lake Mariout together with the upgrades of the East and West Waste Water Treatment Plants in order to achieve at least 5% reduction in the pollution loads entering the Mediterranean Sea through Lake Mariout in order to improve the institutional mechanisms for sustainable coastal zone management in Alexandria in particular to reduce land-based pollution to the Mediterranean Sea.

  8. Transient Electromagnetic Soundings Near Great Sand Dunes National Park and Preserve, San Luis Valley, Colorado (2006 Field Season)

    Science.gov (United States)

    Fitterman, David V.; de Sozua Filho, Oderson A.

    2009-01-01

    Time-domain electromagnetic (TEM) soundings were made near Great Sand Dunes National Park and Preserve in the San Luis Valley of southern Colorado to obtain subsurface information of use to hydrologic modeling. Seventeen soundings were made to the east and north of the sand dunes. Using a small loop TEM system, maximum exploration depths of about 75 to 150 m were obtained. In general, layered earth interpretations of the data found that resistivity decreases with depth. Comparison of soundings with geologic logs from nearby wells found that zones logged as having increased clay content usually corresponded with a significant resistivity decrease in the TEM determined model. This result supports the use of TEM soundings to map the location of the top of the clay unit deposited at the bottom of the ancient Lake Alamosa that filled the San Luis Valley from Pliocene to middle Pleistocene time.

  9. Oil sands tax expenditures

    International Nuclear Information System (INIS)

    Ketchum, K; Lavigne, R.; Plummer, R.

    2001-01-01

    The oil sands are a strategic Canadian resource for which federal and provincial governments provide financial incentives to develop and exploit. This report describes the Oil Sands Tax Expenditure Model (OSTEM) developed to estimate the size of the federal income tax expenditure attributed to the oil sands industry. Tax expenditures are tax concessions which are used as alternatives to direct government spending for achieving government policy objectives. The OSTEM was developed within the business Income Tax Division of Canada's Department of Finance. Data inputs for the model were obtained from oil sands developers and Natural Resources Canada. OSTEM calculates annual revenues, royalties and federal taxes at project levels using project-level projections of capital investment, operating expenses and production. OSTEM calculates tax expenditures by comparing taxes paid under different tax regimes. The model also estimates the foregone revenue as a percentage of capital investment. Total tax expenditures associated with investment in the oil sands are projected to total $820 million for the period from 1986 to 2030, representing 4.6 per cent of the total investment. 10 refs., 2 tabs., 7 figs

  10. Mature fine tailings from oil sands processing harbour diverse methanogenic communities

    Energy Technology Data Exchange (ETDEWEB)

    Penner, T.J.; Foght, J.M. [Alberta Univ., Edmonton, AB (Canada). Dept. of Biological Sciences

    2010-06-15

    Syncrude's bitumen extraction process produces a fine tailings slurry consisting of water, sand, fines, residual bitumen and naphtha diluent. Following rapid settling of the sand fraction, the tailings are stored in large settling ponds to form a thick mature fine tailings (MFT). This paper discussed the potential benefits of methane production on management of the settling basins. Enhanced methanogenesis accelerates densification and improves the rheological properties of MFT. In this study molecular techniques were used to characterize the methanogenic communities in uncultivated MFT samples to determine the diversity present in the Mildred Lake Settling Basin (MLSB) and West In-Pit tailings deposit. The flux of methane is currently estimated at about 40 million L/day at the MLSB. Clone libraries of amplified archaeal and bacterial 16S rRNA genes were created in order to analyze the methanogenic consortia in MFT samples from depth profiles in the 2 tailings deposits. The archaeal sequences, whose closest matches were primarily cultivated methanogens, were comparable within and between basins and were mostly affiliated with acetoclastic Methanosaeta spp. However, bacterial clone libraries were diverse, with most sequences relating to Proteobacteria, including some presumptive nitrate-, iron-, or sulfate-reducing, hydrocarbon-degrading genera. The study showed that MFT consists of a diverse community of prokaryotes that may be responsible for producing methane from substrates indigenous to the MFT. These findings contribute to a better understanding of the biogenesis of methane and densification of MFT in oil sands tailings deposits. The results from this study will help determine strategies to control and exploit microbial activities in these large systems and improve the understanding of methanogenic environments. 43 refs., 2 tabs., 3 figs.

  11. Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication—A Case Study in the Taihu Lake Basin (China)

    Science.gov (United States)

    Lin, Chen; Ma, Ronghua; He, Bin

    2015-01-01

    Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r2 was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality. PMID:26712772

  12. Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication--A Case Study in the Taihu Lake Basin (China).

    Science.gov (United States)

    Lin, Chen; Ma, Ronghua; He, Bin

    2015-12-24

    Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r² was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality.

  13. Singing Sand Dunes

    Indian Academy of Sciences (India)

    ble low-frequency (s. 75–105 Hz), that can some- times be heard up to 10 km away. Scientific in- vestigations suggest that the sustained low fre- quency sound of sand dunes that resembles a pure note from a musical instrument, is due to the synchronized motion of well-sorted dry sand grains when they spontaneously ...

  14. Cancer risk to First Nations’ people from exposure to polycyclic aromatic hydrocarbons near in-situ bitumen extraction in Cold Lake, Alberta

    Science.gov (United States)

    2014-01-01

    Background The Alberta oil sands are an important economic resource in Canada, but there is growing concern over the environmental and health effects as a result of contaminant releases and exposures. Recent studies have shown a temporal and spatial trend of increased polycyclic aromatic hydrocarbon (PAH) concentrations in sediments and snowpack near the Athabasca oil sands operations (i.e., open pit mines), but thus far similar studies have not been done for the Cold Lake region where steam assisted gravity drainage (in situ) extraction is performed. Methods Many PAHs are known mutagenic carcinogens, and this study measured soil and atmospheric concentrations of PAHs in the Cold Lake region to assess the excess lifetime cancer risk posed to the First Nations’ inhabitants of the region. Using both deterministic and probabilistic risk assessment methods, excess lifetime cancer risks were calculated for exposures from inhalation or inadvertent soil ingestion. Results The mean excess cancer risk for First Nations’ people through ingestion who engage in traditional wilderness activities in the Cold Lake region was 0.02 new cases per 100,000 with an upper 95% risk level of 0.07 cases per 100,000. Exposure to PAHs via inhalation revealed a maximum excess lifetime cancer risk of less than 0.1 cases per 100,000. Conclusions Excess lifetime risk values below 1 case per 100,000 is generally considered negligible, thus our analyses did not demonstrate any significant increases in cancer risks associated with PAH exposures for First Nations people inhabiting the Cold Lake region. PMID:24520827

  15. Lake sediments as natural seismographs: Earthquake-related deformations (seismites) in central Canadian lakes

    Science.gov (United States)

    Doughty, M.; Eyles, N.; Eyles, C. H.; Wallace, K.; Boyce, J. I.

    2014-11-01

    Central Canada experiences numerous intraplate earthquakes but their recurrence and source areas remain obscure due to shortness of the instrumental and historic records. Unconsolidated fine-grained sediments in lake basins are 'natural seismographs' with the potential to record ancient earthquakes during the last 10,000 years since the retreat of the Laurentide Ice Sheet. Many lake basins are cut into bedrock and are structurally-controlled by the same Precambrian basement structures (shear zones, terrane boundaries and other lineaments) implicated as the source of ongoing mid-plate earthquake activity. A regional seismic sub-bottom profiling of lakes Gull, Muskoka, Joseph, Rousseau, Ontario, Wanapitei, Fairbanks, Vermilion, Nipissing, Georgian Bay, Mazinaw, Simcoe, Timiskaming, Kipawa, Parry Sound and Lake of Bays, encompassing a total of more than 2000 kilometres of high-resolution track line data supplemented by multibeam and sidescan sonar survey records show a consistent sub-bottom stratigraphy of relatively-thick lowermost lateglacial facies composed of interbedded semi-transparent mass flow facies (debrites, slumps) and rhythmically-laminated silty-clays. Mass flows together with cratered ('kettled') lake floors and associated deformations reflect a dynamic ice-contact glaciolacustrine environment. Exceptionally thick mass flow successions in Lake Timiskaming along the floor of the Timiskaming Graben within the seismically-active Western Quebec Seismic Zone (WQSZ), point to a higher frequency of earthquakes and slope failure during deglaciation and rapid glacio-isostatic rebound though faulting continues into the postglacial. Lateglacial faulting, diapiric deformation and slumping of coeval lateglacial sediments is observed in Parry Sound, Lake Muskoka and Lake Joseph, which are all located above prominent Precambrian terrane boundaries. Lateglacial sediments are sharply overlain by relatively-thin rhythmically-laminated and often semi

  16. Remote Sensing-Derived Bathymetry of Lake Poopó

    Directory of Open Access Journals (Sweden)

    Adalbert Arsen

    2013-12-01

    Full Text Available Located within the Altiplano at 3,686 m above sea level, Lake Poopó is remarkably shallow and very sensitive to hydrologic recharge. Progressive drying has been observed in the entire Titicaca-Poopó-Desaguadero-Salar de Coipasa (TPDS system during the last decade, causing dramatic changes to Lake Poopó’s surface and its regional water supplies. Our research aims to improve understanding of Lake Poopó water storage capacity. Thus, we propose a new method based on freely available remote sensing data to reproduce Lake Poopó bathymetry. Laser ranging altimeter ICESat (Ice, Cloud, and land Elevation Satellite is used during the lake’s lowest stages to measure vertical heights with high precision over dry land. These heights are used to estimate elevations of water contours obtained with Landsat imagery. Contour points with assigned elevation are filtered and grouped in a points cloud. Mesh gridding and interpolation function are then applied to construct 3D bathymetry. Complementary analysis of Moderate Resolution Imaging Spectroradiometer (MODIS surfaces from 2000 to 2012 combined with bathymetry gives water levels and storage evolution every 8 days.

  17. Braidplain, floodplain and playa lake, alluvial-fan, aeolian and palaeosol facies composing a diversified lithogenetical sequence in the permian and triassic of South Devon (England)

    Science.gov (United States)

    Mader, Detlef

    flat seaming the toes of the fan chain. Sedimentation is characterized by flashy discharge with many episodic flood pulses of short periodicity and mainly rapid waning of high-water phases with quick underrunning of the threshold velocity for keeping the large clasts rolling. Pronounced slack water episodes allow occasionally the draping of gravel sheets with thin veneers of waning-flow and stagnant-water fines. Spectacular invertebrate burrows in finer breccias underline the flashy nature of most of the flood and flow events, allowing the colonization of the sediments with ground-living invertebrates during interruptions of transport and accumulation. Some peculiar dewatering structures being infilling of crack systems in breccias with wash-load sand are probably induced by earthquake shocks thus pointing to the active tectonic setting of the depositional area. Aeolian sands originate as transverse dune ridges in restricted dune fields and extensive sand seas and as sheet sands in interdune playa depressions. Associated mudstones and ventifact gravel form in wet interdunes or in playa lakes and in deflationary interdunes, respectively. Accumulation of aeolian dunes and interdune sheet sands takes place by both spreading out of drapes on flats and infilling of abandoned fluvial channels which enhance the trapping of sand by topographical effects. The dunes and wind ripple trains migrate across dry interdune floors under predominantly unidirectional winds. Sedimentary processes are grainfall and grainflow on the lee slope of dunes and subcritical climbing of wind ripples. Episodical wetting and dampening of dry interdune flats by intermittent rainfall, periodical dew and even ephemeral fluvial or alluvial-fan incursions allow formation of adhesion-rippled sands on damp surfaces and origin of sandy and silty-clayey lacustrine sediments in shallow water veneers of the flooded playa. Aquatic modification of aeolian sands by invading flood surges of atmospheric or alluvial

  18. Hydrogeologic framework and hydrologic conditions of the Piney Point aquifer in Virginia

    Science.gov (United States)

    McFarland, E. Randolph

    2017-06-07

    The Piney Point aquifer in Virginia is newly described and delineated as being composed of six geologic units, in a study conducted by the U.S. Geological Survey in cooperation with the Virginia Department of Environmental Quality (VA DEQ). The eastward-dipping geologic units include, in stratigraphically ascending order, thesand of the Nanjemoy Formation Woodstock Member,interbedded limestone and sand of the Piney Point Formation,silty and clayey sand of the Gosport Formation equivalent sediments,silty sand of the Oligocene-age sediments,silty fine-grained sand of the Old Church Formation, andsilty sand of the Calvert Formation, Newport News unit and basal Plum Point Member.Identification of geologic units is based on typical sediment lithologies of geologic formations. Fine-grained sediments that compose confining units positioned immediately above and below the Piney Point aquifer are also described.The Piney Point aquifer is one of several confined aquifers within the Virginia Coastal Plain and includes a highly porous and solution-channeled indurated limestone within the Piney Point Formation from which withdrawals are made. The limestone is relatively continuous laterally across central parts of the Northern Neck, Middle Peninsula, and York-James Peninsula. Other geologic units are of variable extent. The configurations of most of the geologic units are further affected by newly identified faults that are aligned radially from the Chesapeake Bay impact crater and create constrictions or barriers to groundwater flow. Some geologic units are also truncated beneath the lower Rappahannock River by a resurge channel associated with the impact crater.Groundwater withdrawals from the Piney Point aquifer increased from approximately 1 million gallons per day (Mgal/d) during 1900 to 7.35 Mgal/d during 2004. As a result, a water-level cone of depression in James City and northern York Counties was estimated to be as low as 70 feet (ft) below the National Geodetic

  19. Seasonal stability of Cladophora-associated Salmonella in Lake Michigan watersheds

    Science.gov (United States)

    Byappanahalli, M.N.; Sawdey, R.; Ishii, S.; Shively, D.A.; Ferguson, J.A.; Whitman, R.L.; Sadowsky, M.J.

    2009-01-01

    The bacterial pathogens Shigella, Salmonella, Campylobacter, and shiga toxin-producing E. coli (STEC) were recently found to be associated with Cladophora growing in southern Lake Michigan. Preliminary results indicated that the Salmonella strains associated with Cladophora were genetically identical to each other. However, because of the small sample size (n = 37 isolates) and a lack of information on spatial-temporal relationships, the nature of the association between Cladophora and Salmonella remained speculative. In this study, we investigated the population structure and genetic relatedness of a large number of Cladophora-borne Salmonella isolates from Lake Michigan (n = 133), as well as those isolated from stream and lake water (n = 31), aquatic plants (n = 8), and beach sands and sediments (n = 8) from adjacent watersheds. Salmonella isolates were collected during 2005-2007 between May and August from Lake Michigan beachsheds in Wisconsin, Illinois, and Indiana. The genetic relatedness of Salmonella isolates was examined by using the horizontal, fluorophore-enhanced rep-PCR (HFERP) DNA fingerprinting technique. While the Salmonella isolates associated with Cladophora exhibited a high degree of genetic relatedness (???92% similarity), the isolates were not all genetically identical. Spatial and temporal relationships were evident in the populations examined, with tight clustering of the isolates both by year and location. These findings suggest that the relationship between Salmonella and Cladophora is likely casual and is related to input sources (e.g. wastewater, runoff, birds) and the predominant Salmonella genotype surviving in the environment during a given season. Our studies indicate that Cladophora is likely an important reservoir for Salmonella and other enteric bacterial pathogens in Lake Michigan beachsheds, which in turn may influence nearshore water quality. ?? 2008 Elsevier Ltd.

  20. Seasonal stability of Cladophora-associated Salmonella in Lake Michigan watersheds.

    Science.gov (United States)

    Byappanahalli, Muruleedhara N; Sawdey, Richard; Ishii, Satoshi; Shively, Dawn A; Ferguson, John A; Whitman, Richard L; Sadowsky, Michael J

    2009-02-01

    The bacterial pathogens Shigella, Salmonella, Campylobacter, and shiga toxin-producing E. coli (STEC) were recently found to be associated with Cladophora growing in southern Lake Michigan. Preliminary results indicated that the Salmonella strains associated with Cladophora were genetically identical to each other. However, because of the small sample size (n=37 isolates) and a lack of information on spatial-temporal relationships, the nature of the association between Cladophora and Salmonella remained speculative. In this study, we investigated the population structure and genetic relatedness of a large number of Cladophora-borne Salmonella isolates from Lake Michigan (n=133), as well as those isolated from stream and lake water (n=31), aquatic plants (n=8), and beach sands and sediments (n=8) from adjacent watersheds. Salmonella isolates were collected during 2005-2007 between May and August from Lake Michigan beachsheds in Wisconsin, Illinois, and Indiana. The genetic relatedness of Salmonella isolates was examined by using the horizontal, fluorophore-enhanced rep-PCR (HFERP) DNA fingerprinting technique. While the Salmonella isolates associated with Cladophora exhibited a high degree of genetic relatedness (>or=92% similarity), the isolates were not all genetically identical. Spatial and temporal relationships were evident in the populations examined, with tight clustering of the isolates both by year and location. These findings suggest that the relationship between Salmonella and Cladophora is likely casual and is related to input sources (e.g. wastewater, runoff, birds) and the predominant Salmonella genotype surviving in the environment during a given season. Our studies indicate that Cladophora is likely an important reservoir for Salmonella and other enteric bacterial pathogens in Lake Michigan beachsheds, which in turn may influence nearshore water quality.

  1. Reconstructing Heat Fluxes Over Lake Erie During the Lake Effect Snow Event of November 2014

    Science.gov (United States)

    Fitzpatrick, L.; Fujisaki-Manome, A.; Gronewold, A.; Anderson, E. J.; Spence, C.; Chen, J.; Shao, C.; Posselt, D. J.; Wright, D. M.; Lofgren, B. M.; Schwab, D. J.

    2017-12-01

    The extreme North American winter storm of November 2014 triggered a record lake effect snowfall (LES) event in southwest New York. This study examined the evaporation from Lake Erie during the record lake effect snowfall event, November 17th-20th, 2014, by reconstructing heat fluxes and evaporation rates over Lake Erie using the unstructured grid, Finite-Volume Community Ocean Model (FVCOM). Nine different model runs were conducted using combinations of three different flux algorithms: the Met Flux Algorithm (COARE), a method routinely used at NOAA's Great Lakes Environmental Research Laboratory (SOLAR), and the Los Alamos Sea Ice Model (CICE); and three different meteorological forcings: the Climate Forecast System version 2 Operational Analysis (CFSv2), Interpolated observations (Interp), and the High Resolution Rapid Refresh (HRRR). A few non-FVCOM model outputs were also included in the evaporation analysis from an atmospheric reanalysis (CFSv2) and the large lake thermodynamic model (LLTM). Model-simulated water temperature and meteorological forcing data (wind direction and air temperature) were validated with buoy data at three locations in Lake Erie. The simulated sensible and latent heat fluxes were validated with the eddy covariance measurements at two offshore sites; Long Point Lighthouse in north central Lake Erie and Toledo water crib intake in western Lake Erie. The evaluation showed a significant increase in heat fluxes over three days, with the peak on the 18th of November. Snow water equivalent data from the National Snow Analyses at the National Operational Hydrologic Remote Sensing Center showed a spike in water content on the 20th of November, two days after the peak heat fluxes. The ensemble runs presented a variation in spatial pattern of evaporation, lake-wide average evaporation, and resulting cooling of the lake. Overall, the evaporation tended to be larger in deep water than shallow water near the shore. The lake-wide average evaporations

  2. Late Pleistocene to Holocene lake levels of Lake Warner, Oregon (USA) and their effect on archaeological site distribution patterns

    Science.gov (United States)

    Wriston, T.; Smith, G. M.

    2017-12-01

    Few chronological controls are available for the rise and fall of small pluvial lake systems in the Northwestern Great Basin. Within Warner Basin this control was necessary for interpretation of known archaeological sites and for predicting where evidence of its earliest inhabitants might be expected. We trenched along relic beach ridges of Lake Warner, surveyed a stratified sample of the area for archaeological sites, and excavated some sites and a nearby rockshelter. These efforts produced new ages that we used to construct a lake level curve for Lake Warner. We found that the lake filled the valley floor between ca. 30,000 cal yr BP and ca. 10,300 cal yr BP. In nearby basins, several oscillations are evident before ca. 21,100 cal yr BP, but a steep rise to the LGM maximum occurred between 21,000 and 20,000 cal yr BP. Lake Warner likely mirrored these changes, dropped to the valley floor ca. 18,340 cal yr BP, and then rose to its maximum highstand when its waters briefly reached 1454 m asl. After this highstand the lake receded to moderately high levels. Following ca. 14,385 cal yr BP, the lake oscillated between moderate to moderately-high levels through the Bolling-Allerod interstadials and into the Younger Dryas stadial. The basin's first occupants arrived along its shore around this time, while the lake still filled the valley floor. These earliest people carried either Western Stemmed or Clovis projectile points, both of which are found along the lake margin. The lake receded into the valley floor ca. 10,300 cal yr BP and dune development began, ringing wetlands and small lakes that persisted in the footprint of the once large lake. By the time Mazama tephra fell 7,600 cal yr BP it blanketed pre-existing dunes and marsh peats. Our Lake Warner lake level curve facilitates interdisciplinary testing and refinement of it and similar curves throughout the region while helping us understand the history of lake and the people who lived along its shores.

  3. Properties of Desert Sand and CMAS Glass

    Science.gov (United States)

    Bansal, Narottam P.; Choi, Sung R.

    2014-01-01

    As-received desert sand from a Middle East country has been characterized for its phase composition and thermal stability. X-ray diffraction analysis showed the presence of quartz (SiO2), calcite (CaCO3), gypsum (CaSO4.2H2O), and NaAlSi3O8 phases in as-received desert sand and showed weight loss of approx. 35 percent due to decomposition of CaCO3 and CaSO4.2H2O when heated to 1400 C. A batch of as-received desert sand was melted into calcium magnesium aluminosilicate (CMAS) glass at approx. 1500 C. From inductively coupled plasma-atomic emission spectrometry, chemical composition of the CMAS glass was analyzed to be 27.8CaO-4MgO-5Al2O3-61.6SiO2-0.6Fe2O3-1K2O (mole percent). Various physical, thermal and mechanical properties of the glass have been evaluated. Bulk density of CMAS glass was 2.69 g/cc, Young's modulus 92 GPa, Shear modulus 36 GPa, Poisson's ratio 0.28, dilatometric glass transition temperature (T (sub g)) 706 C, softening point (T (sub d)) 764 C, Vickers microhardness 6.3 +/- 0.4 GPa, indentation fracture toughness 0.75 +/- 0.15 MPa.m (sup 1/2), and coefficient of thermal expansion (CTE) 9.8 x 10 (exp -6)/degC in the temperature range 25 to 700 C. Temperature dependence of viscosity has also been estimated from various reference points of the CMAS glass using the Vogel-Fulcher-Tamman (VFT) equation. The glass remained amorphous after heat treating at 850 C for 10 hr but crystallized into CaSiO3 and Ca-Mg-Al silicate phases at 900 C or higher temperatures. Crystallization kinetics of the CMAS glass has also been investigated by differential thermal analysis (DTA). Activation energies for the crystallization of two different phases in the glass were calculated to be 403 and 483 kJ/mol, respectively.

  4. An approach to managing cumulative effects to groundwater resources in the Alberta oil sands

    International Nuclear Information System (INIS)

    Fennell, J.; Forrest, Francine; Klebek, Margaret

    2011-01-01

    In the Athabasca region of Northern Alberta, oil sands activity has raised many concerns over how mining and extracting processes might affect groundwater quality and quantity. The groundwater management framework was developed by Alberta Environment to address these concerns by identifying and managing the potential environmental effects of oil sands activity on groundwater in a science-based manner. This paper develops the framework using risk identification and performance monitoring. The decision-making approach was conducted using decision support tools such as modeling, monitoring and management. Results showed the complexity and variability of groundwater conditions in the Athabasca region and pointed out that knowledge in this area is still developing. This paper presented how the groundwater management framework was developed and pointed out that it will have to be updated as new information arrives.

  5. Source apportionment of nitrogen and phosphorus from non-point source pollution in Nansi Lake Basin, China.

    Science.gov (United States)

    Zhang, Bao-Lei; Cui, Bo-Hao; Zhang, Shu-Min; Wu, Quan-Yuan; Yao, Lei

    2018-05-03

    Nitrogen (N) and phosphorus (P) from non-point source (NPS) pollution in Nansi Lake Basin greatly influenced the water quality of Nansi Lake, which is the determinant factor for the success of East Route of South-North Water Transfer Project in China. This research improved Johnes export coefficient model (ECM) by developing a method to determine the export coefficients of different land use types based on the hydrological and water quality data. Taking NPS total nitrogen (TN) and total phosphorus (TP) as the study objects, this study estimated the contributions of different pollution sources and analyzed their spatial distributions based on the improved ECM. The results underlined that the method for obtaining output coefficients of land use types using hydrology and water quality data is feasible and accurate, and is suitable for the study of NPS pollution at large-scale basins. The average output structure of NPS TN from land use, rural breeding and rural life is 33.6, 25.9, and 40.5%, and the NPS TP is 31.6, 43.7, and 24.7%, respectively. Especially, dry land was the main land use source for both NPS TN and TP pollution, with the contributed proportions of 81.3 and 81.8% respectively. The counties of Zaozhuang, Tengzhou, Caoxian, Yuncheng, and Shanxian had higher contribution rates and the counties of Dingtao, Juancheng, and Caoxian had the higher load intensities for both NPS TN and TP pollution. The results of this study allowed for an improvement in the understanding of the pollution source contribution and enabled researchers and planners to focus on the most important sources and regions of NPS pollution.

  6. Predation of the zebra mussel (Dreissena polymorpha) by freshwater drum in western Lake Erie

    Science.gov (United States)

    French, John R. P.; Bur, Michael T.; Nalepa, Thomas F.; Schloesser, Donald W.

    1992-01-01

    Environmental and economic problems associated with the colonization of zebra mussels (Dreissena polymorpha) in western Lake Erie created a need to investigate control mechanisms. Predation by fishes is one potential means of control, but predation on zebra mussels by native fishes in Lake Erie is unknown. The freshwater drum (Aplodinotus grunniens) is the most likely fish predator since it is the only fish with pharyngeal teeth capable of crushing mollusk shells. In 1990, freshwater drum were collected in western Lake Erie from 9 sites near rocky reefs and 13 sites with silt or sand bottoms, and gut contents were examined. Predation on zebra mussels increased as drum size increased. Small drum (200-249 mm in length) fed mainly on dipterans, amphipods, and small fish; small zebra mussels (375 mm in length) fed almost exclusively on zebra mussels (seasons and locations combined). The smallest drum capable of crushing zebra mussel shells was 265 mm. Since freshwater drum over 375 mm feed heavily on zebra mussels, they may become a possible biological control mechanism for mussels in portions of North America.

  7. Microplastic pollution in lakes and lake shoreline sediments - A case study on Lake Bolsena and Lake Chiusi (central Italy).

    Science.gov (United States)

    Fischer, Elke Kerstin; Paglialonga, Lisa; Czech, Elisa; Tamminga, Matthias

    2016-06-01

    Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Prevalence of toxin-producing Clostridium botulinum associated with the macroalga Cladophora in three Great Lakes: growth and management

    Science.gov (United States)

    Chun, Chan Lan; Kahn, Chase I.; Borchert, Andrew J.; Byappanahalli, Muruleedhara N.; Whitman, Richard L.; Peller, Julie R.; Pier, Christina; Lin, Guangyun; Johnson, Eric A.; Sadowsky, Michael J.

    2015-01-01

    The reemergence of avian botulism caused by Clostridium botulinum type E has been observed across the Great Lakes in recent years. Evidence suggests an association between the nuisance algae, Cladophoraspp., and C. botulinum in nearshore areas of the Great Lakes. However, the nature of the association between Cladophora and C. botulinum is not fully understood due, in part, to the complex food web interactions in this disease etiology. In this study, we extensively evaluated their association by quantitatively examining population size and serotypes of C. botulinum in algal mats collected from wide geographic areas in lakes Michigan, Ontario, and Erie in 2011–2012 and comparing them with frequencies in other matrices such as sand and water. A high prevalence (96%) of C. botulinum type E was observed inCladophora mats collected from shorelines of the Great Lakes in 2012. Among the algae samples containing detectable C. botulinum, the population size of C. Botulinum type E was 100–104 MPN/g dried algae, which was much greater (up to 103 fold) than that found in sand or the water column, indicating thatCladophora mats are sources of this pathogen. Mouse toxinantitoxin bioassays confirmed that the putativeC. botulinum belonged to the type E serotype. Steam treatment was effective in reducing or eliminating C. botulinum type E viable cells in Cladophora mats, thereby breaking the potential transmission route of toxin up to the food chain. Consequently, our data suggest that steam treatment incorporated with a beach cleaning machine may be an effective treatment of Cladophora-borne C. botulinum and may reduce bird mortality and human health risks.

  9. Spatiotemporal variability of carbon dioxide and methane in a eutrophic lake

    Science.gov (United States)

    Loken, Luke; Crawford, John; Schramm, Paul; Stadler, Philipp; Stanley, Emily

    2017-04-01

    Lakes are important regulators of global carbon cycling and conduits of greenhouse gases to the atmosphere; however, most efflux estimates for individual lakes are based on extrapolations from a single location. Within-lake variability in carbon dioxide (CO2) and methane (CH4) arises from differences in water sources, physical mixing, and local transformations; all of which can be influenced by anthropogenic disturbances and vary at multiple temporal and spatial scales. During the 2016 open water season (March - December), we mapped surface water concentrations of CO2 and CH4 weekly in a eutrophic lake (Lake Mendota, WI, USA), which has a predominately agricultural and urban watershed. In total we produced 26 maps of each gas based on 10,000 point measurements distributed across the lake surface. Both gases displayed relatively consistent spatial patterns over the stratified period but exhibited remarkable heterogeneity on each sample date. CO2 was generally undersaturated (global mean: 0.84X atmospheric saturation) throughout the lake's pelagic zone and often differed near river inlets and shorelines. The lake was routinely extremely supersaturated with CH4 (global mean: 105X atmospheric saturation) with greater concentrations in littoral areas that contained organic-rich sediments. During fall mixis, both CO2 and CH4 increased substantially, and concentrations were not uniform across the lake surface. CO2 and CH4 were higher on the upwind side of the lake due to upwelling of enriched hypolimnetic water. While the lake acted as a modest sink for atmospheric CO2 during the stratified period, the lake released substantial amounts of CO2 during turnover and continually emitted CH4, offsetting any reduction in atmospheric warming potential from summertime CO2 uptake. These data-rich maps illustrate how lake-wide surface concentrations and lake-scale efflux estimates based on single point measurements diverge from spatially weighted calculations. Both gases are not

  10. Radiocarbon analysis of halophilic microbial lipids from an Australian salt lake

    Science.gov (United States)

    Bray, P. Sargent; Jones, Claudia M.; Fallon, Stewart J.; Brocks, Jochen J.; George, Simon C.

    2012-01-01

    Assigning accurate dates to hypersaline sediments opens important terrestrial records of local and regional paleoecologies and paleoclimatology. However, as of yet no conventional method of dating hypersaline systems has been widely adopted. Biomarker, mineralogical, and radiocarbon analyses of sediments and organic extracts from a shallow (13 cm) core from a hypersaline playa, Lake Tyrrell, southeastern Australia, produce a coherent age-depth curve beginning with modern microbial mats and extending to ~ 7500 cal yr BP. These analyses are furthermore used to identify and constrain the timing of the most recent change in hydrological regime at Lake Tyrrell, a shift from a clay deposit to the precipitation of evaporitic sands occurring at some time between ~ 4500 and 7000 yr. These analyses show the potential for widespread dating of hypersaline systems integrating the biomarker approach, reinforce the value of the radiocarbon content of biomarkers in understanding the flow of carbon in modern ecologies, and validate the temporal dimension of data provided by biomarkers when dating late Quaternary sediments.

  11. Is Lake Chabot Eutrophic?

    Science.gov (United States)

    Pellegrini, K.; Logan, J.; Esterlis, P.; Lew, A.; Nguyen, M.

    2013-12-01

    veteran member of the East Bay Regional Park District, Hal MacLean, we realized that almost every lake goes through periods of slight eutrophication. Actually, this phenomenon of waxing and waning of nutrient levels is something many species have grown accustomed too. It's just the extreme cases where the water is actively being polluted by a nearby point source that cause so much damage. Overall, despite outward appearances, the lake is relatively healthy. It boasts high biodiversity in and around the lake, housing such species as dragonflies, eucalyptus, bald eagles, halibut, bass, and even tiny silver goldfish. It fluctuates in oxygen and nutrient content just like any other lake, but for now, it isn't cause for too much concern. It's a beloved element of the Castro Valley community and we hope it will remain so for many generations to come.

  12. Influence of the reclamation method of spent moulding sands on the possibility of creating favourable conditions for gases flow in a mould

    Directory of Open Access Journals (Sweden)

    Łucarz M.

    2017-03-01

    Full Text Available The results of investigations concerning the influence of the applied sand matrix (fresh sand, reclaim on the properties of moulding sands used for production of large dimensional castings (ingot moulds, ladles, are presented in the hereby paper. The performed investigations were aimed at determining the influence of various reclamation methods of spent moulding sands on the quality of the obtained reclaimed material. Moulding sands were prepared on the fresh quartz matrix as well as on sand matrices obtained after various reclamation methods. The selected moulding sand parameters were tested (strength, permeability, grindability, ignition losses, pH reactions. It can be stated, on the basis of the performed investigations, that the kind of the applied moulding sand matrix is of an essential meaning from the point of view of creating conditions minimising formation of large amounts of gases and their directional migration in a casting mould.

  13. Review of four major environmental effects monitoring programs in the oil sands region

    International Nuclear Information System (INIS)

    Lott, E.O.; Jones, R.K.

    2010-10-01

    The lack of knowledge on current environmental effects monitoring programs for the mineable oil sands region generates a low public confidence in environment health monitoring and reporting programs for the oil sands operations. In 2010, the Oil Sands Research and Information Network (OSRIN) supervised a study reviewing the major environmental effects monitoring programs that are underway in the Regional Municipality of Wood Buffalo. Four main environmental effects monitoring and reporting organizations existing in the oil sands area were engaged to describe their programs through this study: Alberta Biodiversity Monitoring Institute (ABMI), Cumulative Environmental Management Association (CEMA), Regional Aquatic Monitoring Program (RAMP), Wood Buffalo Environmental Association (WBEA). These different organizations have specific roles in providing information, data and understanding of ecosystem effects. A one page visual summary of environmental effects monitoring in the oil sands area resulted from the information received from these organizations and detailed fact sheets were presented for each one of the programs. The report of this study also presents seven other environmental monitoring initiatives or organizations such as Alberta Environment and Environment Canada environmental effects monitoring program. The main observation that emerged from the review was the lack of detailed understanding shown by the stakeholders regarding the monitoring activities performed in the oil sands area. There is a lack of communication of the different programs that are conducted in the region. The study also pointed out that no efforts were put in cross-linking the various programs to be assured that every concerns related to environmental effects associated with oil sands operations were addressed. A better understanding of environmental effects and an improvement in public confidence in the data and its interpretation would probably be observed with the establishment of a

  14. Field test on sand compaction pile method with copper slag sand; Dosuisai slag wo mochiita SCP koho no shiken seko

    Energy Technology Data Exchange (ETDEWEB)

    Minami, K.; Matsui, H.; Naruse, E.; Kitazume, M. [Port and Harbour Research Inst., Kanagawa (Japan)

    1997-09-20

    This paper describes the sand compaction pile (SCP) method using copper slag sand. The SCP method is a method by which sand compaction piles are constructed in the ground, and improvement can be obtained in a short period. This method has been widely used even in the port areas for enhancing the bearing power of soft clay ground and the lateral resistance of sheet pile. A great deal of sand is required as a material. The sand requires high permeability, proper size distribution with less fine particle fraction content, easy compaction property with enough strength, and easy discharging property from the casing of construction machines as required properties. Recently, it becomes hard to secure proper sand materials. The copper slag sand is obtained from refining process of copper as a by-product which is quenched in water flow and crushed in water. The copper slag sand has higher particle density than that of sand, excellent permeability, and similar size distribution to that of sand. From compaction drainage triaxial compression test and permeability test, it was found that the mechanical properties of copper slag sand did not change by the crushing of grains with keeping excellent permeability. Through the test construction, applicability of the copper slag sand to the SCP method could be confirmed as an alternate material of sand. 17 refs., 9 figs., 4 tabs.

  15. Oil sands development in a carbon constrained world

    Energy Technology Data Exchange (ETDEWEB)

    McDougall, J. [Alberta Research Council, Devon, AB (Canada)

    2006-07-01

    The challenges facing oilsands development in Alberta were discussed in this PowerPoint presentation. In 2005, 71 per cent of Alberta's export value was derived from energy and mining. The author addressed the issue that resource based economies have rarely succeeded in the long term. He then demonstrated how such economies could capture value from technology. The primary focus was on the goal to develop and adapt greenhouse gas (GHG) transformational technologies that will break the link between hydrocarbon energy use and GHG emissions. The role of oil sands in this endeavour was also discussed. Alberta's oil sands are the world's largest hydrocarbon resource, with 315 b bbls proven reserves, and 2.5 t bbls potential reserves. As an important economic driver for Alberta, oil sands production is expected to grow significantly in the next 2 decades. Since bitumen production is more energy intensive than conventional oil, the industry is faced with the challenge of sustainable development. Concentrated GHG emissions create opportunities to proceed with long-term oil sands development with a sustainable level of GHG emissions, but technology and infrastructure are needed to take advantage of them. Current carbon dioxide (CO{sub 2}) storage projects in Alberta were highlighted. The economic potential of geological storage of CO{sub 2} through acid gas injection or deep disposal was discussed in terms of enhanced oil recovery, enhanced coalbed methane recovery, enhanced gas recovery and cost avoidance of CO{sub 2} per tonne. It was emphasized that a long-term vision and commitment is needed to balance with short term problems solving and longer-term strategic agendas. tabs., figs.

  16. The jammed-to-mobile transition in frozen sand under stress

    Science.gov (United States)

    Durham, W. B.; Pathare, A.; Stern, L. A.; Lenferink, H. J.

    2009-12-01

    We conducted laboratory deformation experiments on sand-rich mixtures of sand + ice under sufficient confinement to inhibit macroscopic dilation. Dry sand packs constrained not to dilate when they are under a shearing load reach an immobile or “jammed” state, as load-supporting “force chains” of sand particles form after a small amount of strain and cannot be broken without volume expansion. Our research objective here was to find the minimum volume fraction of ice required to overcome the jammed state. The result surprised us: the required volume fraction is not a fixed number, but depends on the packing characteristics of the sand in question. Experiments were carried out in a triaxial gas deformation rig at confining pressures (60 - 200 MPa) always at least twice the level of differential stresses (11 - 50 MPa) in order to suppress dilatancy. Run temperatures were 223 - 243 K. We used two kinds of quartz sand, one well-sorted, with a maximum dry packing density (MDPD) of about 0.68 sand by volume, and the other a mixture of two sizes, having a higher MDPD of 0.75. Ice volume fraction ranged from well below saturation (where unfilled porosity necessarily remained) to slightly greater than the value of porosity at MDPD. We tested these frozen sands in compression under constant applied differential stress (creep). Strain rates were very low at these conditions, and runs took days or weeks to complete. The amount of strain required to reach the jammed state in ice-undersaturated samples was approximately 0.04, and did not show an obvious dependence on ice content. For both sands, the onset of mobility occurred at approximately 5% above the value of pore volume at MDPD. Furthermore, viscosity of mobile frozen sand near the transition point was extremely sensitive to ice fraction, which implies that at geologic strain rates, far slower than we can reach in the lab, the ice fraction at transition may lie closer to that at MDPD. Cryogenic scanning electron

  17. Holocene climate on the Modoc Plateau, northern California, USA: The view from Medicine Lake

    Science.gov (United States)

    Starratt, Scott W.

    2009-01-01

    Medicine Lake is a small (165 ha), relatively shallow (average 7.3 m), intermediate elevation (2,036 m) lake located within the summit caldera of Medicine Lake volcano, Siskiyou County, California, USA. Sediment cores and high-resolution bathymetric and seismic reflection data were collected from the lake during the fall of 1999 and 2000. Sediments were analyzed for diatoms, pollen, density, grain size (sand/mud ratio), total organic carbon (TOC), and micro-scale fabric analysis. Using both 14C (AMS) dating and tephrochronology, the basal sediments were estimated to have been deposited about 11,400 cal year BP, thus yielding an estimated average sedimentation rate of about 20.66 cm/1,000 year. The lowermost part of the core (11,400–10,300 cal year BP) contains the transition from glacial to interglacial conditions. From about 11,000–5,500 cal year BP, Medicine Lake consisted of two small, steep-sided lakes or one lake with two steep-sided basins connected by a shallow shelf. During this time, both the pollen (Abies/Artemisia ratio) and the diatom (Cyclotella/Navicula ratio) evidences indicate that the effective moisture increased, leading to a deeper lake. Over the past 5,500 years, the pollen record shows that effective moisture continued to increase, and the diatom record indicates fluctuations in the lake level. The change in the lake level pattern from one of the increasing depths prior to about 6,000 cal year BP to one of the variable depths may be related to changes in the morphology of the Medicine Lake caldera associated with the movement of magma and the eruption of the Medicine Lake Glass Flow about 5,120 cal year BP. These changes in basin morphology caused Medicine Lake to flood the shallow shelf which surrounds the deeper part of the lake. During this period, the Cyclotella/Navicula ratio and the percent abundance of Isoetes vary, suggesting that the level of the lake fluctuated, resulting in changes in the shelf area

  18. Galveston Island, Texas, Sand Management Strategies

    Science.gov (United States)

    2016-07-01

    billion m3 of beach quality sand . However, Texas projects to date have not utilized these sources because of transportation costs. The lack of nearby...estimate that the San Luis Pass flood shoal contains approximately 11.8 million yd3 of beach quality sand . However, it is expected that if permits...a source of beach- quality sand . 2. Sand could be intercepted before it reaches the present dry beach. ERDC/CHL TR-16-13 55 3. The volume of

  19. Evaluation of beach grooming techniques on Escherichia coli density in foreshore sand at North Beach, Racine, WI

    Science.gov (United States)

    Kinzelman, Julie L.; Whitman, Richard L.; Byappanahalli, Muruleedhara N.; Jackson, Emma; Bagley, Robert C.

    2003-01-01

    Elevated levels of Escherichia coli(E. coli) in bathing waters at North Beach, a popular recreational site in Racine, Wisconsin, have been a persistent problem often resulting in the issuance of poor water quality advisories. Moreover, waterfowl (mostly Larus delawarensis and L. argentatus) in nearshore and offshore areas are common and may serve as non-point sources for bacterial contamination of recreational waters. Current beach management practice involves daily mechanical grooming of the nearshore sand for aesthetics and removal of hazardous debris. However, this practice has not been evaluated in terms of its effects on E. coli loading to beach sand and potential introduction to contiguous swimming water. In this study, we tested E. coli responses to three treatments: mechanical groomer, daily and twice weekly hand raking, and a control (no raking/grooming). A randomized block design consisted of replicated treatments and one control (10 each), for a total of 40 blocks sampled daily for 10 days. Foreshore sand samples were collected by hand coring to an average depth of 10 cm. Median E. colirecovered were 73 (mechanically groomed), 27 (hand-raked daily), 32 (hand-raked twice weekly), and 22 (control) colony-forming units (CFU) per gram dry weight sand. E. colicounts in sand that was groomed were significantly higher than hand rakings and control (p grooming efficacy and the importance of understanding non-point sources of bacterial contamination.

  20. Current status and historical variations of phthalate ester (PAE) contamination in the sediments from a large Chinese lake (Lake Chaohu).

    Science.gov (United States)

    Kang, Lei; Wang, Qing-Mei; He, Qi-Shuang; He, Wei; Liu, Wen-Xiu; Kong, Xiang-Zhen; Yang, Bin; Yang, Chen; Jiang, Yu-Jiao; Xu, Fu-Liu

    2016-06-01

    The residual levels of phthalate esters (PAEs) in the surface and two core sediments from Lake Chaohu were measured with a gas chromatograph-mass spectrometer (GC-MS). The temporal-spatial distributions, compositions of PAEs, and their effecting factors were investigated. The results indicated that di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl) phthalate (DEHP) were three dominant PAE components in both the surface and core sediments. The residual level of total detected PAEs (∑PAEs) in the surface sediments (2.146 ± 2.255 μg/g dw) was lower than that in the western core sediments (10.615 ± 9.733 μg/g) and in the eastern core sediments (5.109 ± 4.741 μg/g). The average content of ∑PAEs in the surface sediments from the inflow rivers (4.128 ± 1.738 μg/g dw) was an order of magnitude higher than those from the lake (0.323 ± 0.093 μg/g dw), and there were similar PAE compositions between the lake and inflow rivers. This finding means that there were important effects of PAE input from the inflow rivers on the compositions and distributions of PAEs in the surface sediments. An increasing trend was found for the residual levels of ΣPAEs, DnBP, and DIBP from the bottom to the surface in both the western and eastern core sediments. Increasing PAE usage with the population growth, urbanization, and industrial and agricultural development in Lake Chaohu watershed would result in the increasing production of PAEs and their resulting presence in the sediments. The significant positive relationships were also found between the PAE contents and the percentage of sand particles, as well as TOC contents in the sediment cores.

  1. Applications in the oil sands industry for Particlear{sup R} silica microgel

    Energy Technology Data Exchange (ETDEWEB)

    Moffett, B. [DuPont Chemical Solutions Enterprise, Wilmington, DE (United States)

    2009-07-01

    This presentation demonstrated the use of Particlear{sup R} silica microgel in the oil sands industry. The silica-based coagulant is an amorphous silicon dioxide microgel solution. The surface area of a football field can be obtained using 2.7 grams of the substance. The coagulation mechanism is achieved by charge neutralization and inter-particle bridging. The microgel is manufactured at the point of use from commodity chemicals, water, and carbon dioxide (CO{sub 2}). Applications for the microgel include potable water treatment, paper retention, and animal processing wastewater. In the oil sands industry, Particlear{sup R} can be used in tailings flocculation, thickened tailings drying, steam assisted gravity drainage (SAGD) water treatment, and enhanced bitumen recovery. It was concluded that the microgel can be used in many oil sands processing and liquid-solid separation processes in order to remove dissolved solids and organics and increase the rate of solids dewatering. tabs., figs.

  2. Numerical simulation of aeolian sand ripples

    International Nuclear Information System (INIS)

    Kang Liqiang; Guo Liejin

    2004-01-01

    With a new horizontal saltation displacement vector, a model is implemented to simulate the initiation and evolution of aeolian sand ripples. In the model, saltation distance considers the effects of surface height and slope. A linear stability analysis is also carried out for formation of sand ripples. The results show that, the model can be able to successfully reproduce sand ripples which can increase in scale by merging of small ripples. The linear stability analysis indicates that sand ripples appear when the relaxation rate parameter is below a threshold value and wind strength parameter is larger than a critical value. The results also verified that the formation of sand ripples is a self-organization process

  3. Ice-dammed lateral lake and epishelf lake insights into Holocene dynamics of Marguerite Trough Ice Stream and George VI Ice Shelf, Alexander Island, Antarctic Peninsula

    Science.gov (United States)

    Davies, Bethan J.; Hambrey, Michael J.; Glasser, Neil F.; Holt, Tom; Rodés, Angél; Smellie, John L.; Carrivick, Jonathan L.; Blockley, Simon P. E.

    2017-12-01

    We present new data regarding the past dynamics of Marguerite Trough Ice Stream, George VI Ice Shelf and valley glaciers from Ablation Point Massif on Alexander Island, Antarctic Peninsula. This ice-free oasis preserves a geological record of ice stream lateral moraines, ice-dammed lakes, ice-shelf moraines and valley glacier moraines, which we dated using cosmogenic nuclide ages. We provide one of the first detailed sediment-landform assemblage descriptions of epishelf lake shorelines. Marguerite Trough Ice Stream imprinted lateral moraines against eastern Alexander Island at 120 m at Ablation Point Massif. During deglaciation, lateral lakes formed in the Ablation and Moutonnée valleys, dammed against the ice stream in George VI Sound. Exposure ages from boulders on these shorelines yielded ages of 13.9 to 9.7 ka. Following recession of the ice stream, George VI Ice Shelf formed in George VI Sound. An epishelf lake formed at 15-20 m asl in Ablation and Moutonnée valleys, dated from 9.4 to 4.6 ka, suggesting that the lake was stable and persistent for some 5000 years. Lake-level lowering occurred after this, with the lake level at 12 m at 3.1 ± 0.4 ka and at 5 m asl today. A readvance of the valley glaciers on Alexander Island at 4.4 ± 0.7 ka is recorded by valley glacier moraines overlying epishelf lake sediments. We speculate that the glacier readvance, which occurred during a period of warmth, may have been caused by a dynamic response of the glaciers to a lowering in surface elevation of George VI Ice Shelf.

  4. MouldingSandDB – a modern database storing moulding sands properties research results

    Directory of Open Access Journals (Sweden)

    J. Jakubski

    2011-01-01

    Full Text Available The complexity of foundry processes requires the use of modern, advanced IT tools for optimization, storage and analysis of t echnicaldata. Properties of moulding and core sands that are collected in research laboratories, manufacturers, and finally in the foundries, are not in use later on. It seems important to create a database that will allow to use the results stored, along with the possibility of searching according to set criteria, adjusted to casting practice. This paper presents part of the database named „MouldingSandDB”, which allows to collect and search data for synthetic moulding sands.

  5. Dynamics of turbidity plumes in Lake Ontario. [Welland Canal and Niagara, Genesee, and Oswego Rivers

    Science.gov (United States)

    Pluhowski, E. J. (Principal Investigator)

    1975-01-01

    The author has identified the following significant results. Large turbidity features along the 275 km south shore of Lake Ontario were analyzed using LANDSAT-1 images. The Niagara River plume, ranging from 30 to 500 sq km in area is, by far, the largest turbidity feature in the lake. Based on image tonal comparisons, turbidity in the Welland Canal is usually higher than that in any other water course discharging into the lake during the shipping season. Less turbid water enters the lake from the Port Dalhousie diversion channel and the Genesee River. Relatively clear water resulting from the deposition of suspended matter in numerous upstream lakes is discharged by the Niagara and Oswego Rivers. Plume analysis corroborates the presence of a prevailing eastward flowing longshore current along the entire south shore. Plumes resulting from beach erosion were detected in the images. Extensive areas of the south shore are subject to erosion but the most severely affected beaches are situated between Fifty Mile Point, Ontario and Thirty Mile Point, New York along the Rochester embayment, and between Sodus Bay and Nine Mile Point.

  6. Geochemical Anomalies in the Sediments of Lake Druksiai

    International Nuclear Information System (INIS)

    Kleinas, A.

    1999-01-01

    In order to evaluate the impact of Ignalina Nuclear Power Plant (NPP) on natural processes in Lake Druksiai and accumulation of pollutants, in 19931997, carrying on the state scientific program, the Marine Geochemistry Division of the Institute of Geography performed lithological geochemical mapping of lake bottom sediments on a scale of 1 .50 000. The results obtained enabled to distinguish zones of higher anthropogenous geochemical load, where geochemical anomalies of pollutants, including oil hydrocarbons and heavy metals, had been taken into account. Applying concentration coefficients for oil hydrocarbons and heavy metals (Cr, Cu, Ni, Pb, and Zn) and their natural background, the attempt was made to differentiate natural and technogenous components in the geochemical anomalies As expected, the finer sediments -aleurite-pelite mud - showed amounts of oil hydrocarbons and heavy metals being 12.1 times higher than in fine sand - the most coarse of the sediments studied Sediments with organic mater exceeding 20% contained 11.7 times more pollutants than those with organic matter below 1 .5%. Calculations of concentration coefficients (CC) showed no elements in no stations exceeded 10 - the sediments did not reach the category of high pollution However, in many sites, the coefficients exceeded values of 1-2, thus, showing sediments attributable to the categories of weakly polluted or just polluted. Mapping model done by GIS methods (by superimposing schemes of pollutant CCs distribution in the lake and summing them) for geochemical anomalies two derivative map-schemes were obtained for oil hydrocarbons and heavy metals. They showed that clean sediments cover just 24.75% (according to the pollutant background for soil types) and 12.35% (according to the organic matter background for its amount intervals) lake bottom area. Zones slightly polluted by an element at least cover 69.7 and 80.29% of lake area, correspondingly; whereas zones slightly polluted by all

  7. Methane bubbling from northern lakes: present and future contributions to the global methane budget.

    Science.gov (United States)

    Walter, Katey M; Smith, Laurence C; Chapin, F Stuart

    2007-07-15

    Large uncertainties in the budget of atmospheric methane (CH4) limit the accuracy of climate change projections. Here we describe and quantify an important source of CH4 -- point-source ebullition (bubbling) from northern lakes -- that has not been incorporated in previous regional or global methane budgets. Employing a method recently introduced to measure ebullition more accurately by taking into account its spatial patchiness in lakes, we estimate point-source ebullition for 16 lakes in Alaska and Siberia that represent several common northern lake types: glacial, alluvial floodplain, peatland and thermokarst (thaw) lakes. Extrapolation of measured fluxes from these 16 sites to all lakes north of 45 degrees N using circumpolar databases of lake and permafrost distributions suggests that northern lakes are a globally significant source of atmospheric CH4, emitting approximately 24.2+/-10.5Tg CH4yr(-1). Thermokarst lakes have particularly high emissions because they release CH4 produced from organic matter previously sequestered in permafrost. A carbon mass balance calculation of CH4 release from thermokarst lakes on the Siberian yedoma ice complex suggests that these lakes alone would emit as much as approximately 49000Tg CH4 if this ice complex was to thaw completely. Using a space-for-time substitution based on the current lake distributions in permafrost-dominated and permafrost-free terrains, we estimate that lake emissions would be reduced by approximately 12% in a more probable transitional permafrost scenario and by approximately 53% in a 'permafrost-free' Northern Hemisphere. Long-term decline in CH4 ebullition from lakes due to lake area loss and permafrost thaw would occur only after the large release of CH4 associated thermokarst lake development in the zone of continuous permafrost.

  8. Cogs in the endless machine: Lakes, climate change and nutrient cycles: A review

    Energy Technology Data Exchange (ETDEWEB)

    Moss, Brian, E-mail: brmoss@liverpool.ac.uk

    2012-09-15

    Lakes have, rather grandly, been described as sentinels, integrators and regulators of climate change (). Lakes are also part of the continuum of the water cycle, cogs in a machine that processes water and elements dissolved and suspended in myriad forms. Assessing the changes in the functioning of the cogs and the machine with respect to these substances as climate changes is clearly important, but difficult. Many other human-induced influences, not least eutrophication, that impact on catchment areas and consequently on lakes, have generally complicated the recording of recent change in sediment records and modern sets of data. The least confounded evidence comes from remote lakes in mountain and polar regions and suggests effects of warming that include mobilisation of ions and increased amounts of phosphorus. A cottage industry has arisen in deduction and prediction of the future effects of climate change on lakes, but the results are very general and precision is marred not only by confounding influences but by the complexity of the lake system and the infinite variety of possible future scenarios. A common conclusion, however, is that warming will increase the intensity of symptoms of eutrophication. Direct experimentation, though expensive and still unusual and confined to shallow lake and wetland systems is perhaps the most reliable approach. Results suggest increased symptoms of eutrophication, and changes in ecosystem structure, but in some respects are different from those deduced from comparisons along latitudinal gradients or by inference from knowledge of lake behaviour. Experiments have shown marked increases in community respiration compared with gross photosynthesis in mesocosm systems and it may be that the most significant churnings of these cogs in the earth-air-water machine will be in their influence on the carbon cycle, with possibly large positive feedback effects on warming. -- Highlights: Black-Right-Pointing-Pointer Climate change has had

  9. Policy Analysis of the Canadian Oil Sands Experience

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2013-09-01

    For those who support U.S. oil sands development, the Canadian oil sands industry is often identified as a model the U.S. might emulate, yielding financial and energy security benefits. For opponents of domestic oil sands development, the Canadian oil sands experience illustrates the risks that opponents of development believe should deter domestic policymakers from incenting U.S. oil sands development. This report does not seek to evaluate the particular underpinnings of either side of this policy argument, but rather attempts to delve into the question of whether the Canadian experience has relevance as a foundational model for U.S. oil sands development. More specifically, this report seeks to assess whether and how the Canadian oil sands experience might be predictive or instructive in the context of fashioning a framework for a U.S. oil sands industry. In evaluating the implications of these underpinnings for a prospective U.S. oil sands industry, this report concentrates on prospective development of the oil sands deposits found in Utah.

  10. Predicting development of undrained shear strength in soft oil sands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Masala, S. [Klohn Crippen Berger, Calgary, AB (Canada); Matthews, J. [Shell Canada Ltd., Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed a method of predicting the development of undrained shear strength in soft oil sands tailings. Phenomenology charts of oil sands tailings ponds were used to present the suspension, density, stresses and hydrostatic behaviour of tailings. Sedimentation and consolidation processes were discussed. The charts demonstrated how the tailings slurry settles and consolidates, releases water and dissipates pore pressures. The slurry then develops intergranular stresses and increases in density. The increases correlate with increased resistance to deformation and decreased compressibility and hydraulic conductivity. A critical state soil mechanics (CSSM) was used to characterize the soft oil sands tailings. Undrained strength was determined using the concept of the undrained strength ratio (USR). The USR was determined using traditional geotechnical investigation methods. Settling of the non-consolidated (NC) soil deposits was simulated using the finite strain consolidation theory. The model was based on the premise that current effective stresses control undrained shear strength in the NC deposits. Case studies were used to demonstrate the predictive framework. tabs, figs.

  11. A study of global sand seas

    Science.gov (United States)

    McKee, Edwin D.

    1979-01-01

    The birth of the idea that led to this publication on "Global Sand Seas" dates back to the late 1920's. At that time I was engaged in a study of the Coconino Sandstone of Arizona's Grand Canyon. Considerable controversy existed then as to whether this sandstone was a subaqueous deposit or was composed of wind-formed dunes. It became apparent that definitive literature was sparse or lacking on types of dunes, global distribution of these types, the mechanics of their development, the precise nature of their internal structure of cross-stratificiation, and the relation of wind systems to these sand forms. Especially lacking were data on criteria that could confidently be used in the recognition of ancient dunes. The common denominator in this publication is eolian sand bodies. Although the book is concerned primarily with desert sand seas, the subject matter is not restricted to deserts; it includes many references to deposits of coastal sand and to sand bodies in humid climates. Nor does the book deal exclusively with dunes, which, according to most definitions, involve mounds or hills. Many references are made to sand sheets, sand stringers, and other types of sand deposits that have no prominent topographic expression. All sand bodies accumulated by the action of wind are discussed. Chapters A-J of this publication are primarily topical. Chapters cover the grain texture, the color, and the structure of modern dunes and other eolian sands. Special treatment is given to the relation of wind data to dune interpretation, the evolution of form in current-deposited sand bodies as determined from experimental studies, and the discriminant analysis technique for differentiating between coastal and inland desert sands. This topical part of the publication also includes an analysis of criteria used in ancient deposits to interpret their eolian genesis and a consideration of economic application of the principles described, including a discussion of potentials and problems

  12. N:P ratios, light limitation, and cyanobacterial dominance in a subtropical lake impacted by non-point source nutrient pollution

    International Nuclear Information System (INIS)

    Havens, K.E.; James, R.T.; East, T.L.; Smith, V.H.

    2003-01-01

    Low ratios of N:P and low underwater irradiance control dominance of cyanobacteria in a subtropical lake. - A long-term (28-year) data set was used to investigate historical changes in concentrations of phosphorus (P), nitrogen (N), N:P ratios, and Secchi disk transparency in a shallow subtropical lake (Lake Okeechobee, Florida, USA). The aim was to evaluate changes in the risk of N 2 -fixing cyanobacterial blooms, which have infrequently occurred in the lake's pelagic zone. Predictions regarding bloom risk were based on previously published N:P ratio models. Temporal trends in the biomass of cyanobacteria were evaluated using phytoplankton data collected in 1974, 1989-1992, and 1997-2000. Concentrations of pelagic total P increased from near 50 μg l -1 in the mid-1970s to over 100 μg l -1 in the late 1990s. Coincidentally, the total N:P (mass) ratio decreased from 30:1 to below 15:1, and soluble N:P ratio decreased from 15:1 to near 6:1, in the lake water. Published empirical models predict that current conditions favor cyanobacteria. The observations confirm this prediction: cyanobacteria presently account for 50-80% of total phytoplankton biovolume. The historical decrease in TN:TP ratio in the lake can be attributed to a decreased TN:TP ratio in the inflow water and to a decline in the lake's assimilation of P, relative to N. Coincident with these declines in total and soluble N:P ratios, Secchi disk transparency declined from 0.6 m to near 0.3 m, possibly due to increased mineral turbidity in the lake water. Empirical models predict that under the turbid, low irradiance conditions that prevail in this lake, non-heterocystous cyanobacteria should dominate the phytoplankton. Our observations confirmed this prediction: non-N 2 -fixing taxa (primarily Oscillatoria and Lyngbya spp.) typically dominated the cyanobacteria community during the last decade. The only exception was a year with very low water levels, when heterocystous N 2 -fixing Anabaena became

  13. Pinatubo Lake Chemistry and Degassing 1991-2010

    Science.gov (United States)

    Schwandner, F. M.; Newhall, C. G.; Christenson, B. W.; Apfelbeck, C. A.; Arpa, M. C. B.; Vaquilar, R.; Bariso, E.

    2016-12-01

    We review the history of degassing, bathymetry and water chemistry of the crater lake of Mt. Pinatubo (Philippines) using data obtained during 1991-2001, and 2010. In late 1992, the initial small lake had a significant acid-sulfate component from a volcanic degassing through a hydrothermal system and the lake, and anhydrite dissolution. Subsequently, this component was "drowned" by rainfall (2-4 m/y), meteoric groundwater draining from the crater walls into the lake, and a few neutral chloride crater wall springs. Conductivity-Temperature-Depth (CTD) measurements in August 2000 found a strong inverted thermal gradient below 20m depth, reaching over 70°C at 50-60 m depth. By January 2001 the lake had homogenized and was much cooler (27°C at all depths), and it was again well-mixed and still cool when re-surveyed in June 2001 and November 2010. By 2010, the lake was well mixed, at neutral pH, with no significant vertical or horizontal structure. Bubbling of a predominantly carbon dioxide (CO2) gas phase persists throughout the lake's history, some from 1991-92 magma and some from degassing of the long-standing (pre-1991) hydrothermal system fed from a deeper magmatic or mantle source. Crater wall fumaroles emit boiling-point hydrothermal gases dominated by water, air, and CO2.

  14. Varying Inundation Regimes Differentially Affect Natural and Sand-Amended Marsh Sediments.

    Directory of Open Access Journals (Sweden)

    C Wigand

    Full Text Available Climate change is altering sea level rise rates and precipitation patterns worldwide. Coastal wetlands are vulnerable to these changes. System responses to stressors are important for resource managers and environmental stewards to understand in order to best manage them. Thin layer sand or sediment application to drowning and eroding marshes is one approach to build elevation and resilience. The above- and below-ground structure, soil carbon dioxide emissions, and pore water constituents in vegetated natural marsh sediments and sand-amended sediments were examined at varying inundation regimes between mean sea level and mean high water (0.82 m NAVD88 to 1.49 m NAVD88 in a field experiment at Laws Point, part of the Plum Island Sound Estuary (MA. Significantly lower salinities, pH, sulfides, phosphates, and ammonium were measured in the sand-amended sediments than in the natural sediments. In natural sediments there was a pattern of increasing salinity with increasing elevation while in the sand-amended sediments the trend was reversed, showing decreasing salinity with increasing elevation. Sulfide concentrations generally increased from low to high inundation with highest concentrations at the highest inundation (i.e., at the lowest elevations. High pore water phosphate concentrations were measured at low elevations in the natural sediments, but the sand-amended treatments had mostly low concentrations of phosphate and no consistent pattern with elevation. At the end of the experiment the lowest elevations generally had the highest measures of pore water ammonium. Soil carbon dioxide emissions were greatest in the sand-amended mesocosms and at higher elevations. Differences in coarse root and rhizome abundances and volumes among the sediment treatments were detected with CT imaging, but by 20 weeks the natural and sand-amended treatments showed similar total belowground biomass at the intermediate and high elevations. Although differences in

  15. Levels of polycyclic aromatic hydrocarbons and dibenzothiophenes in wetland sediments and aquatic insects in the oil sands area of northeastern Alberta, Canada.

    Science.gov (United States)

    Wayland, Mark; Headley, John V; Peru, Kerry M; Crosley, Robert; Brownlee, Brian G

    2008-01-01

    An immense volume of tailings and tailings water is accumulating in tailings ponds located on mine leases in the oil sands area of Alberta, Canada. Oil sands mining companies have proposed to use tailings- and tailings water-amended lakes and wetlands as part of their mine remediation plans. Polycyclic aromatic hydrocarbons (PAHs) are substances of concern in oil sands tailings and tailings water. In this study, we determined concentrations of PAHs in sediments, insect larvae and adult insects collected in or adjacent to three groups of wetlands: experimental wetlands to which tailings or tailings water had been purposely added, oil sands wetlands that were located on the mine leases but which had not been experimentally manipulated and reference wetlands located near the mine leases. Alkylated PAHs dominated the PAH profile in all types of samples in the three categories of wetlands. Median and maximum PAH concentrations, especially alkylated PAH concentrations, tended to be higher in sediments and insect larvae in experimental wetlands than in the other types of wetlands. Such was not the case for adult insects, which contained higher than expected levels of PAHs in the three types of ponds. Overlap in PAH concentrations in larvae among pond types suggests that any increase in PAH levels resulting from the addition of tailings and tailings water to wetlands would be modest. Biota-sediment accumulation factors were higher for alkylated PAHs than for their parent counterparts and were lower in experimental wetlands than in oil sands and reference wetlands. Research is needed to examine factors that affect the bioavailability of PAHs in oil sands tailings- or tailings water-amended wetlands.

  16. Numerical simulation of wind-sand movement in the reversed flow region of a sand dune with a bridge built downstream.

    Science.gov (United States)

    He, Wei; Huang, Ning; Xu, Bin; Wang, Wenbo

    2018-04-23

    A bridge built inside the reversed flow region of a sand dune will change the characteristics of wind-sand movement in this region. The Reynolds-averaged Navier-Stokes simulation and discrete particle tracing are used to simulate the wind-sand movement around a sand dune with a bridge built inside the reversed region. Three cases with different bridge positions are studied. The results show that 1) compared with the isolated dune case, a tall bridge built at the leeward toe leads to an increase in the deposition rate on the leeward slope and a longer reversed flow region downstream of the sand dune; meanwhile, the high speed of crosswind on the bridge indicates that some measures should be taken to protect trains from strong crosswind; 2) a low bridge at the leeward toe has little effect on the sand deposition and reversed flow region of the dune; however, low sand transport rate and crosswind speed on the bridge show that anti-crosswind/sand measures should be taken according to the actual situation and 3) a low bridge on the leeward slope has little effect on the length of reversed flow region, however, high crosswind speed and sand flux on the bridge reveal the need of anti-crosswind/sand measures on the bridge. Moreover, the bridges in the reversed flow region increase the sand flux near the leeward crest; as a result, the moving patterns of the sand dune are changed.

  17. Terrestrial CDOM in Lakes of Yamal Peninsula: Connection to Lake and Lake Catchment Properties

    Directory of Open Access Journals (Sweden)

    Yury Dvornikov

    2018-01-01

    Full Text Available In this study, we analyze interactions in lake and lake catchment systems of a continuous permafrost area. We assessed colored dissolved organic matter (CDOM absorption at 440 nm (a(440CDOM and absorption slope (S300–500 in lakes using field sampling and optical remote sensing data for an area of 350 km2 in Central Yamal, Siberia. Applying a CDOM algorithm (ratio of green and red band reflectance for two high spatial resolution multispectral GeoEye-1 and Worldview-2 satellite images, we were able to extrapolate the a(λCDOM data from 18 lakes sampled in the field to 356 lakes in the study area (model R2 = 0.79. Values of a(440CDOM in 356 lakes varied from 0.48 to 8.35 m−1 with a median of 1.43 m−1. This a(λCDOM dataset was used to relate lake CDOM to 17 lake and lake catchment parameters derived from optical and radar remote sensing data and from digital elevation model analysis in order to establish the parameters controlling CDOM in lakes on the Yamal Peninsula. Regression tree model and boosted regression tree analysis showed that the activity of cryogenic processes (thermocirques in the lake shores and lake water level were the two most important controls, explaining 48.4% and 28.4% of lake CDOM, respectively (R2 = 0.61. Activation of thermocirques led to a large input of terrestrial organic matter and sediments from catchments and thawed permafrost to lakes (n = 15, mean a(440CDOM = 5.3 m−1. Large lakes on the floodplain with a connection to Mordy-Yakha River received more CDOM (n = 7, mean a(440CDOM = 3.8 m−1 compared to lakes located on higher terraces.

  18. Sand dune tracking from satellite laser altimetry

    Science.gov (United States)

    Dabboor, Mohammed

    Substantial problems arise from sand movement in arid and semi-arid countries. Sand poses a threat to infrastructure, agricultural and urban areas. These issues are caused by the encroachment of sand on roads and railway tracks, farmland, towns and villages, and airports, to name a few. Sand movement highly depends on geomorphology including vegetation cover, shape and height of the terrain, and grain size of the sand. However, wind direction and speed are the most important factors that affect efficient sand movement. The direction of the movement depends on the main direction of the wind, but it has been shown that a minimum wind speed is required, e.g. wind gusts, to initiate sand transport. This fact prevents a simple calculation of sand transport from conventional wind data as wind records rarely contain sub-minute intervals masking out any wind gusts. An alternative of predicting sand transport is the direct observation of sand advance by in situ measurements or via satellite. Until recently, satellite imagery was the only means to compare dune shape and position for predicting dune migration over several years. In 2003, the NASA laser altimetry mission ICESat became operational and monitors elevations over all surface types including sand dunes with an accuracy of about 10-20 cm. In this study, ICESat observations from repeat tracks (tracks overlapping eachother within 50 m) are used to derive sand dune advance and direction. The method employs a correlation of the elevation profiles over several dunes and was sucessfully validated with synthetic data. The accuracy of this method is 5 meters of dune advance. One of the most active areas exhibiting sand and dune movement is the area of the Arabian Peninsula. Approximately one-third of the Arabian Peninsula is covered by sand dunes. Different wind regimes (Shamal, Kaus) cause sand dune movement in the selected study area in the eastern part of the Arabian Peninsula between 20-25 degrees North and 45-55 degrees

  19. 78 FR 46258 - Drawbridge Operation Regulation Lake Washington, Seattle, WA

    Science.gov (United States)

    2013-07-31

    ... that governs the Evergreen Point Floating Bridge (State Route 520 across Lake Washington) at Seattle... Department of Transportation has requested that the draw span of the Evergreen Point Floating Bridge (State... this time, which would divert road traffic onto the Evergreen Point Floating Bridge. The closure of the...

  20. Biogeochemical processes and the diversity of Nhecolândia lakes, Brazil

    Directory of Open Access Journals (Sweden)

    Teodoro I. R Almeida

    2011-06-01

    Full Text Available The Pantanal of Nhecolândia, the world's largest and most diversified field of tropical lakes, comprises approximately 10,000 lakes, which cover an area of 24,000 km² and vary greatly in salinity, pH, alkalinity, colour, physiography and biological activity. The hyposaline lakes have variable pHs, low alkalinity, macrophytes and low phytoplankton densities. The saline lakes have pHs above 9 or 10, high alkalinity, a high density of phytoplankton and sand beaches. The cause of the diversity of these lakes has been an open question, which we have addressed in our research. Here we propose a hybrid process, both geochemical and biological, as the main cause, including (1 a climate with an important water deficit and poverty in Ca2+ in both superficial and phreatic waters; and (2 an elevation of pH during cyanobacteria blooms. These two aspects destabilise the general tendency of Earth's surface waters towards a neutral pH. This imbalance results in an increase in the pH and dissolution of previously precipitated amorphous silica and quartzose sand. During extreme droughts, amorphous silica precipitates in the inter-granular spaces of the lake bottom sediment, increasing the isolation of the lake from the phreatic level. This paper discusses this biogeochemical problem in the light of physicochemical, chemical, altimetric and phytoplankton data.O Pantanal da Nhecolândia é o maior e mais diversificado campo de lagos da região tropical do planeta, com cerca de 10.000 lagos de variadas salinidade, pH, alcalinidade, cor, fisiografia e atividade biológica dispostos em uma área de 24.000 km². Os lagos hipossalinos têm pH variável, baixa alcalinidade, macrófitas e baixa densidade de fitoplâncton. Os lagos salinos tem pH acima de 9 ou 10, elevada alcalinidade, alta densidade de fitoplâncton e praias de areia. A causa da diversidade desses lagos é uma questão ainda em aberto que é abordada nesta pesquisa. Propõe-se como principal causa um

  1. Natural and human controls of the Holocene evolution of the beach, aeolian sand and dunes of Caesarea (Israel)

    Science.gov (United States)

    Roskin, J.; Sivan, D.; Shtienberg, G.; Roskin, E.; Porat, N.; Bookman, R.

    2015-12-01

    The study focuses on the Holocene appearance, chronology and drivers of beach sand deposition and inland aeolian sand transport around the Roman-Byzantine ruins of Caesarea, Israel. Beach sand, sand sheets, nebkha, linear and transverse dunes as well as parabolic and transverse interdunes along two transects were sampled in the current study down to their substrate. Sixteen new optically stimulated luminescence ages cluster at ∼5.9-3.3 ka, ∼1.2-1.1 ka (800-900 AD) and ∼190-120 years ago (1825-1895 AD) indicating times of middle and late Holocene sand sheet depositions and historical dune stabilization. The first age cluster indicates that beach sand accumulated when rates of global sea level rise declined around 6-5 ka. Until ∼4 ka sand sheets encroached up to 2.5 km inland. Historical and archaeological evidence points to sand mobilization since the first century AD. Sand sheets dating to 1.2-1.1 ka, coevally found throughout the dunefield represent sand stabilization due to vegetation reestablishment attributed to gradual and fluctuating decline in human activity from the middle Early Islamic period until the 10th century. Historical and chronological evidence of the existence of transverse and coppice dunes from the 19th century suggest that dunes only formed in the last few centuries. The study illustrates the initial role of natural processes, in this case decline in global sea level rise and the primary and later role of fluctuating human activity upon coastal sand mobility. The study distinguishes between sand sheets and dunes and portrays them as sensors of environmental changes.

  2. Mapping ecosystem services in a Great Lakes estuary supports local decision-making

    Science.gov (United States)

    Estuaries of the Laurentian Great Lakes provide a concentrated supply of ecosystem goods and services from which humans benefit. As long-term centers of human activity, most estuaries of the Great Lakes and have a legacy of chemical contamination, degraded habitats, and non-point...

  3. Palaeolimnological assessment of the reference conditions and ecological status of lakes in Estonia - implications for the European Union Water Framework Directive

    Directory of Open Access Journals (Sweden)

    Heinsalu, Atko

    2009-12-01

    Full Text Available The European Union Water Framework Directive (WFD requires an assessment of reference conditions for lakes, i.e. the conditions expected with only minimal human impact on water bodies. Limnological monitoring records seldom go back more than a few decades and so rarely document the onset of human impact on lakes. Methods of palaeolimnological approaches especially fitted for the purposes of the WFD are described and two case studies, on lakes Rõuge Tõugjärv and Pappjärv, are presented. The palaeolimnological study of Rõuge Tõugjärv demonstrated that a commonly held belief that man-made eutrophication of Estonian lakes is a relatively modern matter of concern and is related to post-industrial population growth and intensification of agriculture is a misconception. The lakes, particularly those in rich soil areas, have been mediated by human impact over millennial time-scales. In many European countries it has been agreed that AD 1850 approximately represents the reference conditions for lakes. Our observations in Rõuge Tõugjärv showed that during that period anthropogenic disturbance on the lake was the greatest. Lake Pappjärv is an example of recent human influence on the aquatic ecosystem that has undergone severe degradation due to infiltration into the ground of a variety of substances from the local bitumen plant, mineral fertilizer storage tanks, and road service sand and salt mixing-grounds that have been accumulating in the lake since the 1950s.

  4. Failure Mode and Effect Analysis (FMEA) Applications to Identify Iron Sand Reject and Losses in Cement Industry : A Case Study

    Science.gov (United States)

    Helia, V. N.; Wijaya, W. N.

    2017-06-01

    One of the main raw materials required in the manufacture of cement is iron sand. Data from the Procurement Department on XYZ Company shows that the number of defective iron sand (reject) fluctuates every month. Iron sand is an important raw material in the cement production process, so that the amount of iron sand reject and losses got financial and non-financial impact. This study aims to determine the most dominant activity as the cause of rejection and losses of iron sands and suggest improvements that can be made by using the approach of FMEA (Failure Mode and Effect Analysis). Data collection techniques in this study was using the method of observation, interviews, and focus group discussion (FGD) as well as the assessment of the experts to identify it. Results from this study is there are four points of the most dominant cause of the defect of iron sand (mining activities, acceptance, examination and delivery). Recommendation for overcoming these problem is presented (vendor improvement).

  5. Orbital rhythms, monsoons, and playa lake response, Olduvai basin, Equatorial East Africa at 1.85-1.75 Ma

    Science.gov (United States)

    Ashley, G. M.

    2001-12-01

    Wet-dry cycles in low latitudes are generally attributed to changes in solar radiation related to the 21 kyr tempo of orbital precession. Stronger insolation drives stronger summer monsoon maxima that increase precipitation and in closed basins produce larger lakes. However, a Plio-Pleistocene record from a closed rift-platform basin near the equator suggests that the obliquity (41 kyr) signal is also present. The 1.85-1.75 Ma sedimentary record deposited in the Olduvai basin, 3oN, reveals clear evidence of periodic expansion and contraction of paleolake Olduvai. The closed basin was 50 km wide and infilled by volcaniclastic material from Ngorongoro volcanic complex in several depositional environments.. A saline-alkaline lake expanded up to 15 km in width and deposited Mg-smectitic claystones. The lake clays in the central basin vary in clay mineralogy and the number of calcite crystal horizons reflecting compositional changes in the lake water. Lake expansions are recorded at the margins where lake clays are intercollated with deltaic and ephemeral fluvial sands and with lake margin wetland deposits. Marine dust records, off both west and east Africa, suggest that the precession signal (21kyr) dominated the climate until 2.8 Ma and the obliquity signal (41kyr) from 2.8 to 0.9 Ma (deMenocal, 1995). In contrast, the stratigraphic sequence for playa lake expansion at Olduvai, that is constrained by the tephra chronology (1.85-1.75 Ma) and paleomagnetic record, documents the combined effects of both obliquity and precession cycles.

  6. Surficial geology and stratigraphy of Pleistocene Lake Manix, San Bernardino County, California

    Science.gov (United States)

    Reheis, Marith C.; Redwine, Joanna R.; Wan, Elmira; McGeehin, John P.; VanSistine, D. Paco

    2014-01-01

    Pluvial Lake Manix and its surrounding drainage basin, in the central Mojave Desert of California, has been a focus of paleoclimate, surficial processes, and neotectonic studies by the U.S. Geological Survey (USGS) since about 2004. The USGS initiated studies of Lake Manix deposits to improve understanding of the paleoclimatic record and the shifts in atmospheric circulation that controlled precipitation in the Mojave Desert. Until approximately 25,000 years ago, Lake Manix was the terminus of the Mojave River, which drains northeasterly from the San Bernardino Mountains; the river currently terminates in the Soda Lake and Silver Lake playas. Pleistocene Lake Manix occupied several subbasins at its maximum extent. This map focuses on the extensive exposures created by incision of the Mojave River and its tributaries into the interbedded lacustrine and alluvial deposits within the central (Cady) and northeastern (Afton) subbasins of Lake Manix, and extends from the head of Afton Canyon to Manix Wash. The map illuminates the geomorphic development and depositional history of the lake and alluvial fans within the active tectonic setting of the eastern California shear zone, especially interactions with the left-lateral Manix fault. Lake Manix left an extraordinarily detailed but complex record of numerous transgressive-regressive sequences separated by desiccation and deposition of fan, eolian, and fluvial deposits, and punctuated by tectonic movements and a catastrophic flood that reconfigured the lake basin. Through careful observation of the intercalated lacustrine and fan sequences and by determining the precise elevations of unit contacts, this record was decoded to understand the response of the lake and river system to the interplay of climatic, geomorphic, and tectonic forces. These deposits are exposed in steep badland topography. Mapping was carried out mostly at scales of 1:12,000, although the map is presented at 1:24,000 scale, and employs custom unit

  7. Snowmelt Timing as a Determinant of Lake Inflow Mixing

    Science.gov (United States)

    Roberts, D. C.; Forrest, A. L.; Sahoo, G. B.; Hook, S. J.; Schladow, S. G.

    2018-02-01

    Snowmelt is a significant source of carbon, nutrient, and sediment loads to many mountain lakes. The mixing conditions of snowmelt inflows, which are heavily dependent on the interplay between snowmelt and lake thermal regime, dictate the fate of these loads within lakes and their ultimate impact on lake ecosystems. We use five decades of data from Lake Tahoe, a 600 year residence-time lake where snowmelt has little influence on lake temperature, to characterize the snowmelt mixing response to a range of climate conditions. Using stream discharge and lake profile data (1968-2017), we find that the proportion of annual snowmelt entering the lake prior to the onset of stratification increases as annual snowpack decreases, ranging from about 50% in heavy-snow years to close to 90% in warm, dry years. Accordingly, in 8 recent years (2010-2017) where hourly inflow buoyancy and discharge could be quantified, we find that decreased snowpack similarly increases the proportion of annual snowmelt entering the lake at weak to positive buoyancy. These responses are due to the stronger effect of winter precipitation conditions on streamflow timing and temperature than on lake stratification, and point toward increased nearshore and near-surface mixing of inflows in low-snowpack years. The response of inflow mixing conditions to snowpack is apparent when isolating temperature effects on snowpack. Snowpack levels are decreasing due to warming temperatures during winter precipitation. Thus, our findings suggest that climate change may lead to increased deposition of inflow loads in the ecologically dynamic littoral zone of high-residence time, snowmelt-fed lakes.

  8. Regional environmental change and human activity over the past hundred years recorded in the sedimentary record of Lake Qinghai, China.

    Science.gov (United States)

    Sha, ZhanJiang; Wang, Qiugui; Wang, Jinlong; Du, Jinzhou; Hu, Jufang; Ma, Yujun; Kong, Fancui; Wang, Zhuan

    2017-04-01

    Environmental change and human activity can be recorded in sediment cores in aquatic systems such as lakes. Information from such records may be useful for environmental governance in the future. Six sediment cores were collected from Lake Qinghai, China and its sublakes during 2012 and 2013. Measurements of sediment grain-size fractions indicate that sedimentation in the north and southwest of Lake Qinghai is dominated by river input, whereas that in Lake Gahai and Lake Erhai is dominated by dunes. The sedimentation rates in Lake Qinghai were calculated to be 0.101-0.159 cm/y, similar to the rates in other lakes on the Qinghai-Tibetan Plateau. Using these data and sedimentation rates from the literature, we compiled the spatial distribution of sedimentation rates. Higher values were obtained in the three main areas of Lake Qinghai: two in river estuaries and one close to sand dunes. Lower values were measured in the center and south of the lake. Measurements of total organic carbon (TOC), total nitrogen (TN), phosphorus concentrations, and TOC/TN ratios in three cores (QH01, QH02, and Z04) revealed four horizons corresponding to times of increased human activity. These anthropogenic events were (1) the development of large areas of cropland in the Lake Qinghai watershed in 1960, (2) the beginning of nationwide fertilizer use and increases in cropland area in the lake watershed after 1970, (3) the implementation of the national program "Grain to Green," and (4) the rapid increase in the tourism industry from 2000. Profiles of Rb, Sr concentrations, the Rb/Sr ratio, and grain-size fraction in core Z04 indicate that the climate has become drier over the past 100 years. Therefore, we suggest that lake sediments such as those in Lake Qinghai are useful media for high-resolution studies of regional environmental change and human activity.

  9. Flood-inundation maps for Lake Champlain in Vermont and in northern Clinton County, New York

    Science.gov (United States)

    Flynn, Robert H.; Hayes, Laura

    2016-06-30

    Digital flood-inundation maps for an approximately100-mile length of Lake Champlain in Addison, Chittenden, Franklin, and Grand Isle Counties in Vermont and northern Clinton County in New York were created by the U.S. Geological Survey (USGS) in cooperation with the International Joint Commission (IJC). The flood-inundationmaps, which can be accessed through the International Joint Commission (IJC) Web site at http://www.ijc.org/en_/, depict estimates of the areal extent flooding correspondingto selected water levels (stages) at the USGS lake gage on the Richelieu River (Lake Champlain) at Rouses Point, N.Y. (station number 04295000). In this study, wind and seiche effects (standing oscillating wave with a long wavelength) were not taken into account and the flood-inundation mapsreflect 11 stages (elevations) for Lake Champlain that are static for the study length of the lake. Near-real-time stages at this lake gage, and others on Lake Champlain, may be obtained on the Internet from the USGS National Water Information System at http://waterdata.usgs.gov/ or the National Weather Service Advanced Hydrologic Prediction Service at http:/water.weather.gov/ahps/, which also forecasts flood hydrographs at the Richelieu River (Lake Champlain) at Rouses Point.Static flood boundary extents were determined for LakeChamplain in Addison, Chittenden, Franklin, and Grand Isle Counties in Vermont and northern Clinton County in New York using recently acquired (2013–2014) lidar (light detection and ranging) and may be referenced to any of the five USGS lake gages on Lake Champlain. Of these five lakgages, USGS lake gage 04295000, Richelieu River (Lake Champlain) at Rouses Point, N.Y., is the only USGS lake gage that is also a National Weather Service prediction location. Flood boundary extents for the Lake Champlain static flood-inundation map corresponding to the May 201 flood(103.2 feet [ft], National Geodetic Vertical Datum [NGVD] 29) were evaluated by comparing these boundary

  10. bentonite-sand mixture as new backfill/buffer material

    International Nuclear Information System (INIS)

    Cui Suli; Liu Jisheng; Zhang Huyuan; Liang Jian

    2008-01-01

    The mixture of bentonite and quartz sand is suggested as a new backfill/buffer material for geological disposal of HLW. To improve the further design of underground laboratory and in-situ industrial construction test, the optimization of sand addition to bentonite is focused at present research stage. Based on summarizing the research results abroad, laboratory tests were conducted on the mixture of GMZ001 bentonite and quartz sand, such as compaction test and swelling tests etc. Test data shows that GMZ bentonite-sand mixture exhibits a favorite compaction with a 30% sand addition, a highest swelling pressure with a 20% sand addition, and a decreasing plasticity with increases in sand addition and pore liquid concentration. (authors)

  11. Comparison between predicted and observed sand waves and sand banks in the North Sea

    NARCIS (Netherlands)

    Hulscher, Suzanne J.M.H.; van den Brink, G.M.

    2001-01-01

    For the first time a prediction model of regular morphological patterns on the seabed was tested against observations of sand wave and sand bank occurrence in the entire North Sea. The model, which originates from first physical principles, predicts this occurrence via two dimensionless parameters

  12. A fluvial mercury budget for Lake Ontario.

    Science.gov (United States)

    Denkenberger, Joseph S; Driscoll, Charles T; Mason, Edward; Branfireun, Brian; Warnock, Ashley

    2014-06-03

    Watershed mercury (Hg) flux was calculated for ten inflowing rivers and the outlet for Lake Ontario using empirical measurements from two independent field-sampling programs. Total Hg (THg) flux for nine study watersheds that directly drain into the lake ranged from 0.2 kg/yr to 13 kg/yr, with the dominant fluvial THg load from the Niagara River at 154 kg/yr. THg loss at the outlet (St. Lawrence River) was 68 kg/yr and has declined approximately 40% over the past decade. Fluvial Hg inputs largely (62%) occur in the dissolved fraction and are similar to estimates of atmospheric Hg inputs. Fluvial mass balances suggest strong in-lake retention of particulate Hg inputs (99%), compared to dissolved total Hg (45%) and methyl Hg (22%) fractions. Wetland land cover is a good predictor of methyl Hg yield for Lake Ontario watersheds. Sediment deposition studies, coupled atmospheric and fluvial Hg fluxes, and a comparison of this work with previous measurements indicate that Lake Ontario is a net sink of Hg inputs and not at steady state likely because of recent decreases in point source inputs and atmospheric Hg deposition.

  13. N:P ratios, light limitation, and cyanobacterial dominance in a subtropical lake impacted by non-point source nutrient pollution.

    Science.gov (United States)

    Havens, Karl E; James, R Thomas; East, Therese L; Smith, Val H

    2003-01-01

    A long-term (28-year) data set was used to investigate historical changes in concentrations of phosphorus (P), nitrogen (N), N:P ratios, and Secchi disk transparency in a shallow subtropical lake (Lake Okeechobee, Florida, USA). The aim was to evaluate changes in the risk of N2-fixing cyanobacterial blooms, which have infrequently occurred in the lake's pelagic zone. Predictions regarding bloom risk were based on previously published N:P ratio models. Temporal trends in the biomass of cyanobacteria were evaluated using phytoplankton data collected in 1974, 1989-1992, and 1997-2000. Concentrations of pelagic total P increased from near 50 microg l-1 in the mid-1970s to over 100 microg l-1 in the late 1990s. Coincidentally, the total N:P (mass) ratio decreased from 30:1 to below 15:1, and soluble N:P ratio decreased from 15:1 to near 6:1, in the lake water. Published empirical models predict that current conditions favor cyanobacteria. The observations confirm this prediction: cyanobacteria presently account for 50-80% of total phytoplankton biovolume. The historical decrease in TN:TP ratio in the lake can be attributed to a decreased TN:TP ratio in the inflow water and to a decline in the lake's assimilation of P, relative to N. Coincident with these declines in total and soluble N:P ratios, Secchi disk transparency declined from 0.6 m to near 0.3 m, possibly due to increased mineral turbidity in the lake water. Empirical models predict that under the turbid, low irradiance conditions that prevail in this lake, non-heterocystous cyanobacteria should dominate the phytoplankton. Our observations confirmed this prediction: non-N2-fixing taxa (primarily Oscillatoria and Lyngbya spp.) typically dominated the cyanobacteria community during the last decade. The only exception was a year with very low water levels, when heterocystous N2-fixing Anabaena became dominant. In the near-shore regions of this shallow lake, low N:P ratios potentially favor blooms of N2-fixing

  14. Sanctuaries for lake trout in the Great Lakes

    Science.gov (United States)

    Stanley, Jon G.; Eshenroder, Randy L.; Hartman, Wilbur L.

    1987-01-01

    Populations of lake trout, severely depleted in Lake Superior and virtually extirpated from the other Great Lakes because of sea lamprey predation and intense fishing, are now maintained by annual plantings of hatchery-reared fish in Lakes Michigan, Huron, and Ontario and parts of Lake Superior. The extensive coastal areas of the Great Lakes and proximity to large populations resulted in fishing pressure on planted lake trout heavy enough to push annual mortality associated with sport and commercial fisheries well above the critical level needed to reestablish self-sustaining stocks. The interagency, international program for rehabilitating lake trout includes controlling sea lamprey abundance, stocking hatchery-reared lake trout, managing the catch, and establishing sanctuaries where harvest is prohibited. Three lake trout sanctuaries have been established in Lake Michigan: the Fox Island Sanctuary of 121, 500 ha, in the Chippewa-Ottawa Treaty fishing zone in the northern region of the lake; the Milwaukee Reef Sanctuary of 160, 000 ha in midlake, in boundary waters of Michigan and Wisconsin; and Julian's Reef Sanctuary of 6, 500 ha, in Illinois waters. In northern Lake Huron, Drummond Island Sanctuary of 55, 000 ha is two thirds in Indian treaty-ceded waters in Michigan and one third in Ontario waters of Canada. A second sanctuary, Six Fathom Bank-Yankee Reef Sanctuary, in central Lake Huron contains 168, 000 ha. Sanctuary status for the Canadian areas remains to be approved by the Provincial government. In Lake Superior, sanctuaries protect the spawning grounds of Gull Island Shoal (70, 000 ha) and Devils Island Shoal (44, 000 ha) in Wisconsin's Apostle Island area. These seven sanctuaries, established by the several States and agreed upon by the States, Indian tribes, the U.S. Department of the Interior, and the Province of Ontario, contribute toward solving an interjurisdictional fishery problem.

  15. Critical State of Sand Matrix Soils

    Science.gov (United States)

    Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong

    2014-01-01

    The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803–0.998, 0.144–0.248, and 1.727–2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated. PMID:24757417

  16. Production and global transport of Titan's sand particles

    Science.gov (United States)

    Barnes, Jason W.; Lorenz, Ralph D.; Radebaugh, Jani; Hayes, Alexander G.; Arnold, Karl; Chandler, Clayton

    2015-06-01

    Previous authors have suggested that Titan's individual sand particles form by either sintering or by lithification and erosion. We suggest two new mechanisms for the production of Titan's organic sand particles that would occur within bodies of liquid: flocculation and evaporitic precipitation. Such production mechanisms would suggest discrete sand sources in dry lakebeds. We search for such sources, but find no convincing candidates with the present Cassini Visual and Infrared Mapping Spectrometer coverage. As a result we propose that Titan's equatorial dunes may represent a single, global sand sea with west-to-east transport providing sources and sinks for sand in each interconnected basin. The sand might then be transported around Xanadu by fast-moving Barchan dune chains and/or fluvial transport in transient riverbeds. A river at the Xanadu/Shangri-La border could explain the sharp edge of the sand sea there, much like the Kuiseb River stops the Namib Sand Sea in southwest Africa on Earth. Future missions could use the composition of Titan's sands to constrain the global hydrocarbon cycle.

  17. High temperature thermal energy storage in moving sand

    Science.gov (United States)

    Turner, R. H.; Awaya, H. I.

    1978-01-01

    Several high-temperature (to 500 C) heat-storage systems using sand as the storage medium are described. The advantages of sand as a storage medium include low cost for sand, widespread availability, non-toxicity, non-degradation characteristics, easy containment, and safety. The systems considered include: stationary sand with closely spaced tubes throughout the volume, the use of a fluidized bed, use of conveyor belt transporter, and the use of a blower rapid transport system. For a stationary sand bed, very close spacing of heat transfer tubes throughout the volume is required, manifesting as high power related system cost. The suggestion of moving sand past or around pipes is intended to reduce the power related costs at the penalty of added system complexity. Preliminary system cost estimates are offered. These rough calculations indicate that mobile sand heat storage systems cost less than the stationary sand approach.

  18. Scope of work-supplemental standards-related fieldwork - Salt Lake City UMTRA Project Site, Salt Lake City, Utah

    International Nuclear Information System (INIS)

    1996-01-01

    This scope of work governs the field effort to conduct transient in situ (hereafter referred to by the trademark name HydroPunch reg-sign) investigative subsurface logging and ground water sampling, and perform well point installation services at the U.S. Department of Energy's (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project site near Salt Lake City, Utah. The HydroPunch reg-sign and well point services subcontractor (the Subcontractor) shall provide services as stated herein to be used to investigate the subsurface, collect and analyze ground water samples, and install shallow well points

  19. Sand to Root Transfer of PAHs and PCBs by Carrots Grown on Sand with Pure Substances and Biosolids Amended Sand

    OpenAIRE

    Sablayrolles, Caroline; Montréjaud-Vignoles, Mireille; Silvestre, Jérôme; Patria, Lucie

    2006-01-01

    A study on behaviour of trace organic compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Polychlorinated Biphenyls, PCB) in a sand-plant system has been carried out, with the reclamation of wastewater treatment plant biosolids for agriculture in mind. Carrot plants (Daucus carota) were grown on soilless culture (sand), to provide optimal transfer conditions, in plant containers inside a temperature regulated greenhouse. There were two types of experiment. The trace organic compounds have i...

  20. Novel foraging in the swash zone on Pacific sand crabs (Emerita analoga, Hippidae) by mallards

    Science.gov (United States)

    Lafferty, Kevin D.; McLaughlin, John P.; Dugan, Jenifer E.

    2013-01-01

    Mallards (Anas platyrhynchos) have been observed foraging on intertidal Pacific sand crabs (Hippidae, Emerita analoga) in the swash zone of sandy beaches around Coal Oil Point Reserve, California, and several other beaches on the west coast since at least November 2010. Unlike foraging shorebirds, Mallards do not avoid incoming swashes. Instead, the incoming swash lifts and deposits them down the beach. Shorebirds and diving ducks commonly feed on sand crabs, but sand crabs appear to be a novel behavior and food source for Mallards. Previous surveys of beaches did not report foraging Mallards on regional beaches, whereas foraging Mallards were common in contemporary (recent) surveys and anecdotal reports. Observations of this potentially new behavior were separated by as much as 1,300 km, indicating that this was not a local phenomenon. Mallards foraged singly, in pairs, and in flocks. An expansion of diet to sand crabs carries risks of exposure to surf, human disturbance, high salt intake, and transmission of acanthocephalan and trematode parasites for Mallards but has the benefit of providing a dependable source of animal protein.

  1. Understanding AL-PAM assisted oil sands tailings treatment

    Energy Technology Data Exchange (ETDEWEB)

    Guo, L.; Maham, Y.; Masliyah, J.; Xu, Z. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2010-07-01

    Technologies currently used to treat oil sands tailings include the composite tailings (CT) process and the thickened tailings (TT) or paste technology process. This PowerPoint presentation discussed a flocculation and filtration method used to produce stackable tailings deposits. Magnafloc 1011 and AL-PAM additions were used as part of the filtration technique to produce very dry filter cakes. The effect of AL-PAM molecular weight and aluminum content on tailings treatments was investigated as well as the effect of tailings characteristics on the performance of flocculant-assisted tailings filtration processes. The AL-PAM molecular structure was studied. An experimental study was conducted to determine the effect of various polymer additions on fresh tailings from an oil sands plant. The study showed that the optimum dosage for settling and filtration was lower for higher molecular weight AL-PAM. A higher aluminum content was beneficial for settling. Increases in the aluminum content did not improve filtration rates, but reduced optimal dosages. Step-by-step details of the supernatant filtration process were provided, as well as photographs of the laboratory study. tabs., figs.

  2. Bathymetry of Lake Erie and Lake Saint Clair

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Erie and Lake Saint Clair has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and...

  3. Analysis of wind-blown sand movement over transverse dunes.

    Science.gov (United States)

    Jiang, Hong; Huang, Ning; Zhu, Yuanjian

    2014-12-01

    Wind-blown sand movement often occurs in a very complicated desert environment where sand dunes and ripples are the basic forms. However, most current studies on the theoretic and numerical models of wind-blown sand movement only consider ideal conditions such as steady wind velocity, flat sand surface, etc. In fact, the windward slope gradient plays a great role in the lift-off and sand particle saltation. In this paper, we propose a numerical model for the coupling effect between wind flow and saltating sand particles to simulate wind-blown sand movement over the slope surface and use the SIMPLE algorithm to calculate wind flow and simulate sands transport by tracking sand particle trajectories. We furthermore compare the result of numerical simulation with wind tunnel experiments. These results prove that sand particles have obvious effect on wind flow, especially that over the leeward slope. This study is a preliminary study on windblown sand movement in a complex terrain, and is of significance in the control of dust storms and land desertification.

  4. Multi-angle Indicators System of Non-point Pollution Source Assessment in Rural Areas: A Case Study Near Taihu Lake

    Science.gov (United States)

    Huang, Lei; Ban, Jie; Han, Yu Ting; Yang, Jie; Bi, Jun

    2013-04-01

    This study aims to identify key environmental risk sources contributing to water eutrophication and to suggest certain risk management strategies for rural areas. The multi-angle indicators included in the risk source assessment system were non-point source pollution, deficient waste treatment, and public awareness of environmental risk, which combined psychometric paradigm methods, the contingent valuation method, and personal interviews to describe the environmental sensitivity of local residents. Total risk values of different villages near Taihu Lake were calculated in the case study, which resulted in a geographic risk map showing which village was the critical risk source of Taihu eutrophication. The increased application of phosphorus (P) and nitrogen (N), loss vulnerability of pollutant, and a lack of environmental risk awareness led to more serious non-point pollution, especially in rural China. Interesting results revealed by the quotient between the scores of objective risk sources and subjective risk sources showed what should be improved for each study village. More environmental investments, control of agricultural activities, and promotion of environmental education are critical considerations for rural environmental management. These findings are helpful for developing targeted and effective risk management strategies in rural areas.

  5. Sand consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Spain, H H

    1965-01-21

    In a sand consolidation method in which there is injected a mixture of resin-forming liquids comprising an aryl-hydroxy low molecular weight compound, a water- soluble aldehyde, and a catalyst, an improvement is claimed which comprises diluting the resin-forming liquids with a diluent and with water so that the yield of the resin is sufficient to consolidate the sand particles with the minimum desirable pressure. The diluent may be mutually soluble in water and in the resin-forming liquids, and does not affect the setting time of the polymer. The aldehyde and the aryl-hydroxy compound may be in ratio of 5:1, and the diluent, methyl alcohol, is present in a ratio of 2:1 with reference to the water.

  6. Lake whitefish diet, condition, and energy density in Lake Champlain and the lower four Great Lakes following dreissenid invasions

    Science.gov (United States)

    Herbst, Seth J.; Marsden, J. Ellen; Lantry, Brian F.

    2013-01-01

    Lake Whitefish Coregonus clupeaformis support some of the most valuable commercial freshwater fisheries in North America. Recent growth and condition decreases in Lake Whitefish populations in the Great Lakes have been attributed to the invasion of the dreissenid mussels, zebra mussels Dreissena polymorpha and quagga mussels D. bugensis, and the subsequent collapse of the amphipod, Diporeia, a once-abundant high energy prey source. Since 1993, Lake Champlain has also experienced the invasion and proliferation of zebra mussels, but in contrast to the Great Lakes, Diporeia were not historically abundant. We compared the diet, condition, and energy density of Lake Whitefish from Lake Champlain after the dreissenid mussel invasion to values for those of Lake Whitefish from Lakes Michigan, Huron, Erie, and Ontario. Lake Whitefish were collected using gill nets and bottom trawls, and their diets were quantified seasonally. Condition was estimated using Fulton's condition factor (K) and by determining energy density. In contrast to Lake Whitefish from some of the Great Lakes, those from Lake Champlain Lake Whitefish did not show a dietary shift towards dreissenid mussels, but instead fed primarily on fish eggs in spring, Mysis diluviana in summer, and gastropods and sphaeriids in fall and winter. Along with these dietary differences, the condition and energy density of Lake Whitefish from Lake Champlain were high compared with those of Lake Whitefish from Lakes Michigan, Huron, and Ontario after the dreissenid invasion, and were similar to Lake Whitefish from Lake Erie; fish from Lakes Michigan, Huron, and Ontario consumed dreissenids, whereas fish from Lake Erie did not. Our comparisons of Lake Whitefish populations in Lake Champlain to those in the Great Lakes indicate that diet and condition of Lake Champlain Lake Whitefish were not negatively affected by the dreissenid mussel invasion.

  7. Diagenesis and sedimentology of the Clearwater Formation at Tucker Lake

    Energy Technology Data Exchange (ETDEWEB)

    Hutcheon, I; Abercrombie, H J; Putnam, P; Gardner, R; Krouse, H R

    1989-03-01

    The Clearwater Formation at Tucker Lake Alberta, contains heavy oil and is the site of a steam simulation pilot. The best developed reservoir intervals are north-south oriented distributary channel fill and rivermouth bar sand-stones. Oil bearing sands are underlain by a water zone and calcite cements are more abundant in the transition zone. Mineralogy and petrography were studied by x-ray diffraction analysis and scanning electron microscopy, and carbon and oxygen isotope ratios were measured for calcite in the samples studied. The diagenetic history is complex. Early diagenetic minerals include pyrite, quarts, K-feldspar and albite overgrowths, isopachous calcite, iron-rich chlorite, siderite and smectite. Further burial and modification of fluid composition resulted in dissolution of framework mineral grains and precipitation of clinoptilolite and opal. The emplacement of oil retarded mineral diageneses, and was accompanied by a change in aqeous fluid composition. Kaolinite was deposited during and after oil deposition as relativley fresh water entered the Clearwater Formation. The degradation and fermentation of oil and introduction of meteoric water resulted in the production of a late, isotopically distinct, post-bitumen calite cement. 29 refs., 12 figs.

  8. Direct Chlorination of Zircon Sand

    International Nuclear Information System (INIS)

    Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

    2002-01-01

    It was investigated the direct chlorination of zircon sand in a unit chlorination equipment. The process was in semi batch. The product gas was scrubbed in aqueous NaOH. It was search the influence of time, ratio of reactant and size of particle sand to the concentration of Zr and Si in the product. From these research it was found that as the times, ratio of reactant increased, the concentration of Zr increased, but the concentration of Si decreased, while as grain size of zircon sand decreased the concentration of Zr decreased, but the concentration of Si increased. (author)

  9. Thermal Conductivity of Polymer Composite poypropilene-Sand

    International Nuclear Information System (INIS)

    Betha; Mashuri; Sudirman; Karo Karo, Aloma

    2001-01-01

    Thermal conductivity composite materials polypropylene (PP)-sand have been investigated. PP composite with sand to increase thermal conductivity from the polymer. The composite in this observation is done by mixing matrix (PP melt flow 2/10)and filler sand)by means tool labo plastomil. The result of thermal conductivity is composite of PP-sand which is obtained increase and followed by the raising of filler particle volume fraction. The analysis of thermal conductivity based on the model Cheng and Vachon, model Lewis and Nielsen where this model has the function to support experiment finding. It is proved that Lewis' and Nielsen's model almost approach experiment result. And then thermal conductivity raising will be analyzed by the model of pararel-series conductive with the two (2)phases system. It is showed that sand in PP MF 2 composite have the big role to increase the thermal conductivity than sand in PP MF 10 composition, but it is not easy to shape conductive medium

  10. Final report on Thermally Modified Sand demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-23

    The use of salt and salt/sand mixtures on icy roadway surfaces has dramatically increased during the past 30 years. Despite extensive documentation on salt related damage to the roadway improvements, vehicles and the environment, road maintenance departments have continued to rely on this practice. Road maintenance departments in northern climate areas have long recognized the safety benefits for public mobility on icy roadways from the use of sand. As an abrasive material, the sand improves the surface traction that results in more drivable and less hazardous road conditions during the winter months. Stockpiles of pure sand stored during the winter months oftentimes freeze into large unworkable, monolithic piles. To maintain a free-flowing condition, it has been found to be necessary to add salt to the sand. The addition of salt in amounts ranging from 5 to 10 percent to that of sand, is usually sufficient to provide relatively free-flowing abrasive material that could be stored in stockpiles and applied to icy road surfaces with conventional sand spreading trucks. Another alternative for winter storage of pure sand to maintain a free-flowing condition is in humidity-controlled, heated buildings. As would be expected, this method has high capital and operating costs. and not cost effective for general highway maintenance use. The invention demonstrated herein is a method of thermally modifying pure sand that will remain in a free-flowing state throughout the winter season without the need for the salt additive. The thermally modified sand provides an abrasive material that when applied to icy roads does not cause environmental and corrosive damage as done by the application of sand with salt. By employing a very simple process of freezing screened sand particles by forced air convection under subfreezing conditions, the invention creates a product that has significant value in terms of economic and environmental benefits.

  11. Evaluate of head loss, sediment value and copper removal in sand media (rapid sand filter

    Directory of Open Access Journals (Sweden)

    Daneshi Navab

    2014-06-01

    Full Text Available Along with the technology development and increasing consumption of water resources, we are experiencing low qualities in the mentioned resources. Copper brings about serious environment al pollution, threatening human health and ecosystem. This metal found variously in water resources and industrial activities. Therefore, it needs to treat the water resources from these excessive amounts. Different methods have used for this reason but the most used method during recent years has been the absorption by economic absorbers such as sand. Rapid sand filters usually used in water and wastewater treatment plants for water clarification. In this research, a single layer gravity rapid sand filter has used to reduce different concentrations of copper. sediment value and head loss arising in filter media is simulated by using combination of Carman-Kozeny, Rose and Gregory models in different discharges of rapid sand filter. Results have shown that with increasing in discharge and decreasing in input copper concentration, arriving time to given head loss, is increasing. In addition, results demonstrated that with increasing in copper concentration in influent, removal efficiency is decreasing somewhat. Results of this research can applied in an appropriate design of rapid sand filter to copper removal, a prediction of rapid sand filter ability to copper removal and an estimation of arising head loss during filter work thus evaluating of time interval backwash. DOI: http://dx.doi.org/10.3126/ije.v3i2.10641 International Journal of the Environment Vol.3(2 2014: 276-286

  12. Glacial lake inventory and lake outburst potential in Uzbekistan.

    Science.gov (United States)

    Petrov, Maxim A; Sabitov, Timur Y; Tomashevskaya, Irina G; Glazirin, Gleb E; Chernomorets, Sergey S; Savernyuk, Elena A; Tutubalina, Olga V; Petrakov, Dmitriy A; Sokolov, Leonid S; Dokukin, Mikhail D; Mountrakis, Giorgos; Ruiz-Villanueva, Virginia; Stoffel, Markus

    2017-08-15

    Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002-2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10m. This record was complemented with data from field studies of the last 50years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500m and if lakes had an area exceeding 100m 2 . As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. In situ recovery of oil from Utah tar sand: a summary of tar sand research at the Laramie Energy Technology Center

    Energy Technology Data Exchange (ETDEWEB)

    Marchant, L.C.; Westhoff, J.D.

    1985-10-01

    This report describes work done by the United States Department of Energy's Laramie Energy Technology Center from 1971 through 1982 to develop technology for future recovery of oil from US tar sands. Work was concentrated on major US tar sand deposits that are found in Utah. Major objectives of the program were as follows: determine the feasibility of in situ recovery methods applied to tar sand deposits; and establish a system for classifying tar sand deposits relative to those characteristics that would affect the design and operation of various in situ recovery processes. Contents of this report include: (1) characterization of Utah tar sand; (2) laboratory extraction studies relative to Utah tar sand in situ methods; (3) geological site evaluation; (4) environmental assessments and water availability; (5) reverse combustion field experiment, TS-1C; (6) a reverse combustion followed by forward combustion field experiment, TS-2C; (7) tar sand permeability enhancement studies; (8) two-well steam injection experiment; (9) in situ steam-flood experiment, TS-1S; (10) design of a tar sand field experiment for air-stream co-injection, TS-4; (11) wastewater treatment and oil analyses; (12) economic evaluation of an in situ tar sand recovery process; and (13) appendix I (extraction studies involving Utah tar sands, surface methods). 70 figs., 68 tabs.

  14. Study on sand particles creep model and open pit mine landslide mechanism caused by sand fatigue liquefaction

    Science.gov (United States)

    Du, Dong-Ning; Wang, Lai-Gui; Zhang, Xiang-Dong; Zhang, Shu-Kun

    2017-06-01

    The sand particles in the sand - rock composite slope of the open pit mine occurs creep deformation and fatigue liquefaction under the action of vehicle load vibration and hydraulic gradient, which causes landslide geological disasters and it destroys the surface environment. To reveal the mechanism, a mechanics model based on the model considering the soil structural change with a new “plastic hinge” element is developed, to improve its constitutive and creep curve equations. Data from sand creep experiments are used to identify the parameters in the model and to validate the model. The results show that the mechanical model can describe the rotation progress between the sand particles, disclose the negative acceleration creep deformation stage during the third phase, and require fewer parameters while maintaining accuracy. It provides a new creep model considering rotation to analyze sand creep mechanism, which provides a theoretical basis for revealing the open pit mine landslide mechanism induced by creep deformation and fatigue liquefaction of sandy soil.

  15. Removal of heavy metals using a microbial active, continuously operated sand filter

    International Nuclear Information System (INIS)

    Ebner, C.

    2001-01-01

    Heavy metals play an important role within the spectrum of the various pollutants, emitted into the environment via human activities. In contrast to most organic pollutants, heavy metal can not be degraded. Many soils, lakes and rivers show a high contamination with heavy metals due to the enrichment of these pollutants. In addition to existing chemical-physical and biological technologies for the treatment of heavy metal containing waste waters a demand for new, efficient and low-cost cleaning technologies exists, particularly for high volumes of weakly contaminated waters. Such a technology was developed within the framework of a scientific project of the European Union. The approach makes use of a continuously operated, moving-bed Astrasand filter, which has been operated as a continuous biofilm reactor. By inoculation of the reactor with bacteria providing different, defined mechanisms of metal immobilization, and by continuous supply of suitable nutrients, a metal-immobilizing biofilm is built up and regenerated continuously. Metal-enriched biomass is removed continuously from the system, and the contained metals can be recycled by pyrometallurgical treatment of the biomass. The subjects of the present work were the optimization of the nutrient supply for the process of metal removal, the investigation of the toxicity of different waste waters, the optimization of inoculation and biofilm formation, set-up and operation of a lab scale sand filter and the operation of a pilot scale sand filter treating rinsing water of a chemical nickel plating plant. First, basic parameters like toxicity of heavy metal-containing waste waters and the influence of the nutrition of bacteria on biosorption and total metal removal were examined, using freely suspended bacteria in batch culture. Concerning toxicity great differences could be found within the spectrum of heavy metal-containing waste waters tested. Some waters completely inhibited growth, while others did not

  16. Levels of toxic metals in multisectoral samples from Winam Gulf of Lake Victoria.

    Science.gov (United States)

    Ongeri, D M K; Lalah, J O; Wandiga, S O; Schramm, K W; Michalke, B

    2009-01-01

    In this study, the distribution and sources of inputs of trace metals including Cd, Cu, Zn and Pb from various sources as well as Fe which is widely used in the construction industry, into Winam Gulf of Lake Victoria were investigated. The sampling sites were located up streams and down streams of four rivers (Sio, Nyamasaria, Nyando and Sondu-Miriu), in four beaches along the lake (Port Victoria, Kisumu Car Wash, Dunga and Hippo point beaches) and in three estates (Nyamasaria, Migosi and Nyawita) in Kisumu city, covering potential agrochemical and industrial sources and drinking water points, respectively. The concentrations (in microg/L) of trace metals analysed in the lake and river waters ranged from Car Wash area. The study confirmed that the concentrations of the metals accumulate downstream in the rivers both in water and sediment and these rivers are major sources of the heavy metal load into Winam Gulf of Lake Victoria.

  17. Retorting of bituminous sands

    Energy Technology Data Exchange (ETDEWEB)

    Chaney, P E; Ince, R W; Mason, C M

    1872-09-26

    This method of recovering oil from mined tar sands involves forming compacted tar sands pieces by special conditioning treatment that provides low internal permeability. The compacted pieces are then retorted in fixed bed form. The conditioning treatment can involve rolling of preformed pellets, compaction in a mold or pressure extrusion. Substantial collapsing of the bed during retorting is avoided. (9 claims) (Abstract only - original article not available from T.U.)

  18. Use of sand wave habitats by silver hake

    Science.gov (United States)

    Auster, P.J.; Lindholm, J.; Schaub, S.; Funnell, G.; Kaufman, L.S.; Valentine, P.C.

    2003-01-01

    Silver hake Merluccius bilinearis are common members of fish communities in sand wave habitats on Georges Bank and on Stellwagen Bank in the Gulf of Maine. Observations of fish size v. sand wave period showed that silver hake are not randomly distributed within sand wave landscapes. Regression analyses showed a significant positive relationship between sand wave period and fish length. Correlation coefficients, however, were low, suggesting other interactions with sand wave morphology, the range of current velocities, and available prey may also influence their distribution. Direct contact with sand wave habitats varied over diel periods, with more fish resting on the seafloor during daytime than at night. Social foraging, in the form of polarized groups of fish swimming in linear formations during crepuscular and daytime periods, was also observed. Sand wave habitats may provide shelter from current flows and mediate fish-prey interactions. ?? 2003 The Fisheries Society of the British Isles.

  19. Investigations of the Quality of the Reclaim of Spent Moulding Sands with Organic Binders

    Directory of Open Access Journals (Sweden)

    R. Dańko

    2012-09-01

    Full Text Available Modern investigation methods and equipment for the quality estimation of the moulding sands matrices with organic binders, in theircirculation process, are presented in the paper. These methods, utilising the special equipment combined with the authors investigationmethods developed in the Faculty of Foundry Engineering, AGH the University of Science and Technology, allow for the better estimationof the matrix quality. Moulding sands systems with organic binders require an in-depth approach to factors deciding on the matrixtechnological suitability as well as on their environmental impact. Into modern methods allowing for the better assessment of the matrixquality belongs the grain size analysis of the reclaimed material performed by means of the laser diffraction and also the estimation of the moulding sand gas evolution rate and identification of the emitted gases and their BTEX group gases content, since they are specially hazardous from the point of view of the Occupational Safety and Health.

  20. Investigations of the Quality of The Reclaim of Spent Moulding Sands with Organic Binders

    Directory of Open Access Journals (Sweden)

    Dańko R.

    2012-09-01

    Full Text Available Modern investigation methods and equipment for the quality estimation of the moulding sands matrices with organic binders, in their circulation process, are presented in the paper. These methods, utilising the special equipment combined with the authors investigation methods developed in the Faculty of Foundry Engineering, AGH the University of Science and Technology, allow for the better estimation of the matrix quality. Moulding sands systems with organic binders require an in-depth approach to factors deciding on the matrix technological suitability as well as on their environmental impact. Into modern methods allowing for the better assessment of the matrix quality belongs the grain size analysis of the reclaimed material performed by means of the laser diffraction and also the estimation of the moulding sand gas evolution rate and identification of the emitted gases and their BTEX group gases content, since they are specially hazardous from the point of view of the Occupational Safety and Health.

  1. Punctuated sediment record resulting from channel migration in a shallow sand-dominated micro-tidal lagoon, Northern Wadden Sea, Denmark

    DEFF Research Database (Denmark)

    Fruergaard, M.; Andersen, T.J.; Nielsen, L.H.

    2011-01-01

    depositional environment, but tidal channel sediments dominate in the five sediment cores, making up 56% of the 15 mof sediment core. Sedimentation in the lagoon alternated between slow vertical aggradation of sand flats (1.5–2 mm yr-1) and very fast lateral progradation of point bars in tidal channels, which...... caused the formation of a punctuated lagoonal fill. Frequent and comprehensive reworking of the sand flat sediments by tidal channel migration entails loss of sedimentary structures and bioturbation related to sand flat deposits, and old sand flat sediments are only very sparsely preserved. We further...... conclude that long-term (millennial timescale) sediment accumulation in the lagoon was controlled by rising sea-level, whereas short-term (centurial timescale) sediment accumulation was controlled by local erosion and depositional events caused by lateral migration of channels. Records of short-term sea...

  2. Tidal dynamics in the sand motor lagoon

    NARCIS (Netherlands)

    De Vries, S.; Radermacher, M.; De Schipper, M.A.; Stive, M.J.F.

    2015-01-01

    The Sand Motor is a mega-nourishment characterized by a very large sand volume of around 20 million m3 placed along the Dutch coast. The Sand Motor is a pilot project to evaluate the performance of an alternative nourishment strategy with respect to different functions of the coastal system. Within

  3. Bathymetric mapping of submarine sand waves using multiangle sun glitter imagery: a case of the Taiwan Banks with ASTER stereo imagery

    Science.gov (United States)

    Zhang, Hua-guo; Yang, Kang; Lou, Xiu-lin; Li, Dong-ling; Shi, Ai-qin; Fu, Bin

    2015-01-01

    Submarine sand waves are visible in optical sun glitter remote sensing images and multiangle observations can provide valuable information. We present a method for bathymetric mapping of submarine sand waves using multiangle sun glitter information from Advanced Spaceborne Thermal Emission and Reflection Radiometer stereo imagery. Based on a multiangle image geometry model and a sun glitter radiance transfer model, sea surface roughness is derived using multiangle sun glitter images. These results are then used for water depth inversions based on the Alpers-Hennings model, supported by a few true depth data points (sounding data). Case study results show that the inversion and true depths match well, with high-correlation coefficients and root-mean-square errors from 1.45 to 2.46 m, and relative errors from 5.48% to 8.12%. The proposed method has some advantages over previous methods in that it requires fewer true depth data points, it does not require environmental parameters or knowledge of sand-wave morphology, and it is relatively simple to operate. On this basis, we conclude that this method is effective in mapping submarine sand waves and we anticipate that it will also be applicable to other similar topography types.

  4. 27 CFR 9.83 - Lake Erie.

    Science.gov (United States)

    2010-04-01

    ... on the islands of Lake Erie across the States of New York, Pennsylvania, and Ohio. The beginning... approximately one mile north of Rock Creek, Ohio. (7) The boundary proceeds southwestward, then westward, then... is reached which is due north of the easternmost point of Kelleys Island. (9) The boundary then...

  5. Numerical simulation of flow and compression of green sand

    DEFF Research Database (Denmark)

    Hovad, Emil

    The focus of the industrial PhD project was concentrated on the production of the sand mold (green sand) which gives the cast component its final geometrical shape. In order to ensure a high quality of the cast component, it is important to control the manufacturing process of the mold itself so...... that it is homogeneous and stable. Therefore gaining a basic understanding of how the flow and deposition of green sand should be characterized and modelled was important, so that it could be used for simulation of the manufacturing process of the sand mold. The flowability of the green sand is important when the sand...... flows down through the hopper filling the chamber with sand during the sand shot. The flowability of green sand is mostly governed by the amount of water and bentonite which both decrease it. The flowability and the internal forces thus control how well you can fill a complex mold geom-etry in which...

  6. Effects-Directed Analysis of Dissolved Organic Compounds in Oil Sands Process-Affected Water.

    Science.gov (United States)

    Morandi, Garrett D; Wiseman, Steve B; Pereira, Alberto; Mankidy, Rishikesh; Gault, Ian G M; Martin, Jonathan W; Giesy, John P

    2015-10-20

    Acute toxicity of oil sands process-affected water (OSPW) is caused by its complex mixture of bitumen-derived organics, but the specific chemical classes that are most toxic have not been demonstrated. Here, effects-directed analysis was used to determine the most acutely toxic chemical classes in OSPW collected from the world's first oil sands end-pit lake. Three sequential rounds of fractionation, chemical analysis (ultrahigh resolution mass spectrometry), and acute toxicity testing (96 h fathead minnow embryo lethality and 15 min Microtox bioassay) were conducted. Following primary fractionation, toxicity was primarily attributable to the neutral extractable fraction (F1-NE), containing 27% of original organics mass. In secondary fractionation, F1-NE was subfractionated by alkaline water washing, and toxicity was primarily isolated to the ionizable fraction (F2-NE2), containing 18.5% of the original organic mass. In the final round, chromatographic subfractionation of F2-NE2 resulted in two toxic fractions, with the most potent (F3-NE2a, 11% of original organic mass) containing predominantly naphthenic acids (O2(-)). The less-toxic fraction (F3-NE2b, 8% of original organic mass) contained predominantly nonacid species (O(+), O2(+), SO(+), NO(+)). Evidence supports naphthenic acids as among the most acutely toxic chemical classes in OSPW, but nonacidic species also contribute to acute toxicity of OSPW.

  7. Comparative analysis of discharges into Lake Michigan, Phase I - Southern Lake Michigan.

    Energy Technology Data Exchange (ETDEWEB)

    Veil, J. A.; Elcock, D.; Gasper, J. R.; Environmental Science Division

    2008-06-30

    BP Products North America Inc. (BP) owns and operates a petroleum refinery located on approximately 1,700 acres in Whiting, East Chicago, and Hammond, Indiana, near the southern tip of Lake Michigan. BP provided funding to Purdue University-Calumet Water Institute (Purdue) and Argonne National Laboratory (Argonne) to conduct studies related to wastewater treatment and discharges. Purdue and Argonne are working jointly to identify and characterize technologies that BP could use to meet the previous discharge permit limits for total suspended solids (TSS) and ammonia after refinery modernization. In addition to the technology characterization work, Argonne conducted a separate project task, which is the subject of this report. In Phase I of a two-part study, Argonne estimated the current levels of discharge to southern Lake Michigan from significant point and nonpoint sources in Illinois, Indiana, and portions of Michigan. The study does not consider all of the chemicals that are discharged. Rather, it is narrowly focused on a selected group of pollutants, referred to as the 'target pollutants'. These include: TSS, ammonia, total and hexavalent chromium, mercury, vanadium, and selenium. In Phase II of the study, Argonne will expand the analysis to cover the entire Lake Michigan drainage basin.

  8. Sand wave fields beneath the Loop Current, Gulf of Mexico: Reworking of fan sands

    Science.gov (United States)

    Kenyon, Neil H.; Akhmetzhanov, A.M.; Twichell, D.C.

    2002-01-01

    Extensive fields of large barchan-like sand waves and longitudinal sand ribbons have been mapped by deep-towed SeaMARC IA sidescan sonar on part of the middle and lower Mississippi Fan that lies in about 3200 m of water. The area is beneath the strongly flowing Loop Current. The bedforms have not been adequately sampled but probably consist of winnowed siliciclastic-foraminiferal sands. The size (about 200 m from wingtip to wingtip) and shape of the large barchans is consistent with a previously observed peak current speed of 30 cm/s, measured 25 m above the seabed. The types of small-scale bedforms and the scoured surfaces of chemical crusts, seen on nearby bottom photographs, indicate that near-bed currents in excess of 30 cm/s may sometimes occur. At the time of the survey the sand transport direction was to the northwest, in the opposite direction to the Loop Current but consistent with there being a deep boundary current along the foot of the Florida Escarpment. Some reworking of the underlying sandy turbidites and debris flow deposits is apparent on the sidescan sonar records. Reworking by deep-sea currents, resulting in erosion and in deposits characterised by coarsening upwards structures and cross-bedding, is a process that has been proposed for sand found in cores in shallower parts of the Gulf of Mexico. This process is more widespread than hitherto supposed. 

  9. Oil sands and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Seeley, R. [Shell Canada Ltd., Calgary, AB (Canada). Calgary Research Centre

    2004-07-01

    Oil sands are a significant resource for Alberta and Canada with continuing growth opportunity. There is a need to ensure sustainable development of the oil sands resources from a social, economic and environmental perspective. The industry has succeeded in terms of proven reserves, technology advancements, reduced operating costs, reliability and market accessibility. Some of the major challenges facing the industry include high capital cost, infrastructure, social services and keeping pace with growth. This presentation outlined the proactive measures that the oil sands industry has taken to manage environmental issues such as sulphur dioxide and nitrogen oxide emissions, greenhouse gases, water management and land reclamation. tabs., figs.

  10. Alberta oil sands royalty regime

    International Nuclear Information System (INIS)

    Asgarpour, S.

    2004-01-01

    The long term objective of the Oil Sands Business Unit of Alberta Energy is to pave the way for Alberta's bitumen production to reach 3 million barrels per day by 2020. This presentation described the national government's role in resource development. It was emphasized that since the Crown is the owner of the oil sands resource, it would benefit by providing strategic leadership and by generating a larger royalty base. The oil sands fiscal regime was described with reference to generic royalty, risk sharing, investment, and project economics. Business rule principles were also outlined along with criteria for project expansions. Both upstream and downstream challenges and opportunities were listed. 4 figs

  11. Experimental study of optimal self compacting concrete with spent foundry sand as partial replacement for M-sand using Taguchi approach

    Directory of Open Access Journals (Sweden)

    Nirmala D.B.

    2016-06-01

    Full Text Available This paper presents the application of Taguchi approach to obtain optimal mix proportion for Self Compacting Concrete (SCC containing spent foundry sand and M-sand. Spent foundry sand is used as a partial replacement for M-sand. The SCC mix has seven control factors namely, Coarse aggregate, M-sand with Spent Foundry sand, Cement, Fly ash, Water, Super plasticizer and Viscosity modifying agent. Modified Nan Su method is used to proportion the initial SCC mix. L18 (21×37 Orthogonal Arrays (OA with the seven control factors having 3 levels is used in Taguchi approach which resulted in 18 SCC mix proportions. All mixtures are extensively tested both in fresh and hardened states to verify whether they meet the practical and technical requirements of SCC. The quality characteristics considering “Nominal the better” situation is applied to the test results to arrive at the optimal SCC mix proportion. Test results indicate that the optimal mix satisfies the requirements of fresh and hardened properties of SCC. The study reveals the feasibility of using spent foundry sand as a partial replacement of M-sand in SCC and also that Taguchi method is a reliable tool to arrive at optimal mix proportion of SCC.

  12. Experimental study of optimal self compacting concrete with spent foundry sand as partial replacement for M-sand using Taguchi approach

    Science.gov (United States)

    Nirmala, D. B.; Raviraj, S.

    2016-06-01

    This paper presents the application of Taguchi approach to obtain optimal mix proportion for Self Compacting Concrete (SCC) containing spent foundry sand and M-sand. Spent foundry sand is used as a partial replacement for M-sand. The SCC mix has seven control factors namely, Coarse aggregate, M-sand with Spent Foundry sand, Cement, Fly ash, Water, Super plasticizer and Viscosity modifying agent. Modified Nan Su method is used to proportion the initial SCC mix. L18 (21×37) Orthogonal Arrays (OA) with the seven control factors having 3 levels is used in Taguchi approach which resulted in 18 SCC mix proportions. All mixtures are extensively tested both in fresh and hardened states to verify whether they meet the practical and technical requirements of SCC. The quality characteristics considering "Nominal the better" situation is applied to the test results to arrive at the optimal SCC mix proportion. Test results indicate that the optimal mix satisfies the requirements of fresh and hardened properties of SCC. The study reveals the feasibility of using spent foundry sand as a partial replacement of M-sand in SCC and also that Taguchi method is a reliable tool to arrive at optimal mix proportion of SCC.

  13. Lake-level frequency analysis for Devils Lake, North Dakota

    Science.gov (United States)

    Wiche, Gregg J.; Vecchia, Aldo V.

    1996-01-01

    Two approaches were used to estimate future lake-level probabilities for Devils Lake. The first approach is based on an annual lake-volume model, and the second approach is based on a statistical water mass-balance model that generates seasonal lake volumes on the basis of seasonal precipitation, evaporation, and inflow. Autoregressive moving average models were used to model the annual mean lake volume and the difference between the annual maximum lake volume and the annual mean lake volume. Residuals from both models were determined to be uncorrelated with zero mean and constant variance. However, a nonlinear relation between the residuals of the two models was included in the final annual lakevolume model.Because of high autocorrelation in the annual lake levels of Devils Lake, the annual lake-volume model was verified using annual lake-level changes. The annual lake-volume model closely reproduced the statistics of the recorded lake-level changes for 1901-93 except for the skewness coefficient. However, the model output is less skewed than the data indicate because of some unrealistically large lake-level declines. The statistical water mass-balance model requires as inputs seasonal precipitation, evaporation, and inflow data for Devils Lake. Analysis of annual precipitation, evaporation, and inflow data for 1950-93 revealed no significant trends or long-range dependence so the input time series were assumed to be stationary and short-range dependent.Normality transformations were used to approximately maintain the marginal probability distributions; and a multivariate, periodic autoregressive model was used to reproduce the correlation structure. Each of the coefficients in the model is significantly different from zero at the 5-percent significance level. Coefficients relating spring inflow from one year to spring and fall inflows from the previous year had the largest effect on the lake-level frequency analysis.Inclusion of parameter uncertainty in the model

  14. Lake trout in northern Lake Huron spawn on submerged drumlins

    Science.gov (United States)

    Riley, Stephen C.; Binder, Thomas; Wattrus, Nigel J.; Faust, Matthew D.; Janssen, John; Menzies, John; Marsden, J. Ellen; Ebener, Mark P.; Bronte, Charles R.; He, Ji X.; Tucker, Taaja R.; Hansen, Michael J.; Thompson, Henry T.; Muir, Andrew M.; Krueger, Charles C.

    2014-01-01

    Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.

  15. Lake sturgeon population characteristics in Rainy Lake, Minnesota and Ontario

    Science.gov (United States)

    Adams, W.E.; Kallemeyn, L.W.; Willis, D.W.

    2006-01-01

    Rainy Lake contains a native population of lake sturgeon Acipenser fulvescens that has been largely unstudied. The aims of this study were to document the population characteristics of lake sturgeon in Rainy Lake and to relate environmental factors to year-class strength for this population. Gill-netting efforts throughout the study resulted in the capture of 322 lake sturgeon, including 50 recaptures. Lake sturgeon in Rainy Lake was relatively plump and fast growing compared with a 32-population summary. Population samples were dominated by lake sturgeon between 110 and 150 cm total length. Age–structure analysis of the samples indicated few younger (<10 years) lake sturgeon, but the smallest gill net mesh size used for sampling was 102 mm (bar measure) and would not retain small sturgeon. Few lake sturgeon older than age 50 years were captured, and maximum age of sampled fish was 59 years. Few correlations existed between lake sturgeon year-class indices and both annual and monthly climate variables, except that mean June air temperature was positively correlated with year-class strength. Analysis of Rainy Lake water elevation and resulting lake sturgeon year-class strength indices across years yielded consistent but weak negative correlations between late April and early June, when spawning of lake sturgeon occurs. The baseline data collected in this study should allow Rainy Lake biologists to establish more specific research questions in the future.

  16. Oil sands tailings management project

    Energy Technology Data Exchange (ETDEWEB)

    Godwalt, C. [Alberta WaterSMART, Calgary, AB (Canada); Kotecha, P. [Suncor Energy Inc, Calgary, AB (Canada); Aumann, C. [Alberta Innovates - Technology Futures, Alberta Governement, AB (Canada)

    2010-11-15

    The Oil sands leadership initiative (OSLI) works with the Government of Alberta on the development of the oil sands industry, considering environmental, economical and social aspects. Water management was identified as one of most important areas to focus on. Alberta WaterSMART was requested to support the development and the management of projects resulting from the work done or underway in this field. The development of a regional water management solution stood out as the most interesting solution to obtain significant results. In the Athabasca Region, oil sands producers work independently on their water sourcing and disposal with particular attention to fresh water conservation and economics. The Athabasca River represents a source for mines and distant saline aquifers are the target of steam assisted gravity drainage (SAGD) operators. As part of a four-phase project aiming to study the environmental and economic footprint (EEF) benefit of alternatives for Athabasca oil sands production water supply and disposal, the purpose of the tailings water management project was to identify tailings treatment technologies that are ready to be implemented, and to design and evaluate solutions in order to improve regional oil sands production water sourcing and disposal. Alternatives were evaluated based on their total EEF, applying a lifecycle assessment methodology with a particular attention on the quantification of important performance indicators. 25 refs., 8 tabs., 40 figs.

  17. Oil sands tailings management project

    International Nuclear Information System (INIS)

    Godwalt, C.; Kotecha, P.; Aumann, C.

    2010-11-01

    The Oil sands leadership initiative (OSLI) works with the Government of Alberta on the development of the oil sands industry, considering environmental, economical and social aspects. Water management was identified as one of most important areas to focus on. Alberta WaterSMART was requested to support the development and the management of projects resulting from the work done or underway in this field. The development of a regional water management solution stood out as the most interesting solution to obtain significant results. In the Athabasca Region, oil sands producers work independently on their water sourcing and disposal with particular attention to fresh water conservation and economics. The Athabasca River represents a source for mines and distant saline aquifers are the target of steam assisted gravity drainage (SAGD) operators. As part of a four-phase project aiming to study the environmental and economic footprint (EEF) benefit of alternatives for Athabasca oil sands production water supply and disposal, the purpose of the tailings water management project was to identify tailings treatment technologies that are ready to be implemented, and to design and evaluate solutions in order to improve regional oil sands production water sourcing and disposal. Alternatives were evaluated based on their total EEF, applying a lifecycle assessment methodology with a particular attention on the quantification of important performance indicators. 25 refs., 8 tabs., 40 figs.

  18. Zooplankton communities in a large prealpine lake, Lake Constance: comparison between the Upper and the Lower Lake

    Directory of Open Access Journals (Sweden)

    Gerhard MAIER

    2005-08-01

    Full Text Available The zooplankton communities of two basins of a large lake, Lake Constance, were compared during the years 2002 and 2003. The two basins differ in morphology, physical and chemical conditions. The Upper Lake basin has a surface area of 470 km2, a mean depth of 100 and a maximum depth of 250 m; the Lower Lake basin has a surface area of 62 km2, a mean depth of only 13 and a maximum depth of 40 m. Nutrient, chlorophyll-a concentrations and mean temperatures are somewhat higher in the Lower than in the Upper Lake. Total abundance of rotifers (number per m2 lake surface was higher and rotifer development started earlier in the year in the Lower than in the Upper Lake. Total abundance of crustaceans was higher in the Upper Lake in the year 2002; in the year 2003 no difference in abundance could be detected between the lake basins, although in summer crustacean abundance was higher in the Lower than in the Upper Lake. Crustacean communities differed significantly between lake basins while there was no apparent difference in rotifer communities. In the Lower Lake small crustaceans, like Bosmina spp., Ceriodaphnia pulchella and Thermocyclops oithonoides prevailed. Abundance (number per m2 lake surface of predatory cladocerans, large daphnids and large copepods was much lower in the Lower than in the Upper Lake, in particular during the summer months. Ordination with nonmetric multidimensional scaling (NMS separated communities of both lakes along gradients that correlated with temperature and chlorophyll a concentration. Clutches of copepods were larger in the Lower than in the Upper Lake. No difference could be detected in clutch size of large daphnids between lake basins. Our results show that zooplankton communities in different basins of Lake Constance can be very different. They further suggest that the lack of large crustaceans in particular the lack of large predatory cladocerans in the Lower Lake can have negative effects on growth and

  19. Invasive plants on disturbed Korean sand dunes

    Science.gov (United States)

    Kim, Kee Dae

    2005-01-01

    The sand dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of sand dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused by invasive plants. The relationships between the degree of invasion and 14 environmental variables were studied. Plots of sand dunes along line transects perpendicular to the coastal lines were established to estimate vegetative species coverage. TWINSPAN (Two-Way Indicator Species Analysis), CCA (Canonical Correspondence Analysis), and DCCA (Detrended Canonical Correspondence Analysis) were performed to classify communities on sand dunes and assess species composition variation. Carex kobomugi, Elymus mollis, and Vitex rotundifolia were found to be the dominant species plotted on the east, the west, and the peripheral coasts of Cheju Island, respectively. Vegetation on the south coast was totally extinct. The 19 communities, including representative C. kobomugi, C. kobomugi- Ixeris repens, C. kobomugi- Oenothera biennis, E. mollis, Lolium multiflorum- Calystegia soldanella, and V. rotundifolia- C. kobomugi, were all classified according to TWINSPAN. Oenothera biennis and L. multiflorum were exotics observed within these native communities. CCA showed that invasive native and exotic species distribution was segregated significantly, according to disturbance level, exotic species number, gravel, sand and silt contents, as well as vegetation size. It further revealed that human disturbance can strongly favor the settlement of invasive and exotic species. Restoration options to reduce exotic plants in the South Korean sand dune areas were found to be the introduction of native plant species from one sand dune into other sand dune areas, prohibition of building and the introduction of exotic

  20. Characteristics of SCC with Fly Ash and Manufactured Sand

    Science.gov (United States)

    Praveen Kumar, K.; Radhakrishna

    2016-09-01

    Self compacting concrete (SCC) of M40 grade was designed. The binder in SCC consists of OPC and fly ash in the ratio of 65:35. River sand was replaced by manufactured sand (M-sand) at replacement levels of 20,40,60,80 and 100%. An attempt was made to evaluate the workability and strength characteristics of self compacting concrete with river sand and manufactured sand as fine aggregates. For each replacement level, constant workability was maintained by varying the dosage of superplasticizer. T50 flow time, V Funnel time, V-funnel T5 time as well as compressive, split tensile and flexural strength of SCC were found at each replacement level of M-sand. They were compared to SCC with river sand. Results indicate favourable use of M-sand in preparation of Self Compacting Concrete.

  1. Water Surface Overgrowing of the Tatra’s Lakes

    Directory of Open Access Journals (Sweden)

    Kapusta Juraj

    2018-03-01

    Full Text Available Tatra’s lakes are vulnerable ecosystems and an important element of the alpine landscape. Mainly some shallow lake basins succumb to intense detritus sedimentation, fine fractions of material from the catchment area or to the overgrowing of water level by vegetation. In this paper, changes and dynamics of the 12 Tatra’s lake shorelines that were selected based on the detailed mapping of their extent are pointed out. Changes were assessed by accurate comparisons of historical and current orthophoto maps from the years 1949, 1955 and 2015 – and therefore, based on the oldest and the latest relevant materials. Due to the overgrowing of lakes caused by vegetation, their water surface decreased from −0.9% up to −47.9%, during the examined period. Losses were caused by the overgrowing of open water surface by the communities of sedges and peat bogs. The most significant dynamics of the shorelines during the last decades were reached by those lakes, into which fine sediments were simultaneously deposited by means of mountain water coarse. These sediments made the marginal parts of the lake basins shallower and accelerated rapid expansion of vegetation to the detriment of the open water surface. The overgrowing of shallow moraine lakes lying in the vegetation zone is a significant phenomenon of the High Tatras alpine landscape. It leads to their gradual extinction, turn into peat bogs and wet alpine meadows.

  2. Sand Transport under Highly Turbulent Airflow on a Beach Surface

    Science.gov (United States)

    Baas, A. C. W.; Jackson, D. W. T.; Cooper, J. A. G.; Lynch, K.; Delgado-Fernandez, I.; Beyers, J. H. M.

    2012-04-01

    The past decade has seen a growing body of research on the relation between turbulence in the wind and the resultant transport of sediment over active sand surfaces. Widespread use of sonic anemometry and high-frequency sand transport sensors and traps have facilitated recent field studies over dunes and beach surfaces, to move beyond monitoring of mean wind speed and bulk transport to more detailed measurements at much higher spatio-temporal resolutions. In this paper we present results of a field study conducted in the recirculation flow and re-attachment zone on a beach behind a foredune at Magilligan Strand, Northern Ireland. The offshore winds over the foredune at this site are associated with flow separation and reversal located over the beach surface in the lee of the dune row, often strong enough to induce sand transport toward the toe of the foredune ('against' the overall offshore flow). The re-attachment and recirculation zone are associated with strongly turbulent fluid flow and complex streamlines that do not follow the underlying topography. High frequency (25 Hz) wind and sand transport data were collected at a grid of point locations distributed over the beach surface between 35 m to 55 m distance from the 10 m high dune crest, using ultrasonic anemometers at 0.5 m height and co-located load cell traps and Safires at the bed surface. The wind data are used to investigate the role of Reynolds shear stresses and quadrant analysis techniques for identifying burst-sweep events in relation to sand transport events. This includes an assessment of the issues involved with data rotations for yaw, pitch, and roll corrections relative to complex flow streamlines, and the subsequently derived turbulence parameters based on fluctuating vector components (u', v', w'). Results illustrate how transport may exist under threshold mean velocities because of the role played by coherent flow structures, and the findings corroborate previous findings that shear velocity

  3. Properties of dune sand concrete containing coffee waste

    Directory of Open Access Journals (Sweden)

    Mohamed Guendouz

    2018-01-01

    Full Text Available In the last years, an increase of coffee beverages consumption has been observed all over the world; and its consumption increases the waste coffee grounds which will become an environmental problems. Recycling of this waste to produce new materials like sand concrete appears as one of the best solutions for reduces the problem of pollution. This work aims to study the possibility of recycling waste coffee grounds (Spent Coffee Grounds (SCG as a fine aggregate by replacing the sand in the manufacturing of dune sand concrete. For this; sand concrete mixes were prepared with substitution of sand with the spent coffee grounds waste at different percentage (0%, 5%, 10%, 15% and 20% by volume of the sand in order to study the influence of this wastes on physical (Workability, bulk density and porosity, mechanical (compressive and flexural strength and Thermal (Thermal conductivity and thermal diffusivity properties of dune sand concrete. The results showed that the use of spent coffee grounds waste as partial replacement of natural sand contributes to reduce workability, bulk density and mechanical strength of sand concrete mixes with an increase on its porosity. However, the thermal characteristics are improved and especially for a level of 15% and 20% of substitution. So, it is possible to obtain an insulating material which can be used in the various types of structural components. This study ensures that reusing of waste coffee grounds in dune sand concrete gives a positive approach to reduce the cost of materials and solve some environmental problems.

  4. Lake trout rehabilitation in Lake Erie: a case history

    Science.gov (United States)

    Cornelius, Floyd C.; Muth, Kenneth M.; Kenyon, Roger

    1995-01-01

    Native lake trout (Salvelinus namaycush) once thrived in the deep waters of eastern Lake Erie. The impact of nearly 70 years of unregulated exploitation and over 100 years of progressively severe cultural eutrophication resulted in the elimination of lake trout stocks by 1950. Early attempts to restore lake trout by stocking were unsuccessful in establishing a self-sustaining population. In the early 1980s, New York's Department of Environmental Conservation, Pennsylvania's Fish and Boat Commission, and the U.S. Fish and Wildlife Service entered into a cooperative program to rehabilitate lake trout in the eastern basin of Lake Erie. After 11 years of stocking selected strains of lake trout in U.S. waters, followed by effective sea lamprey control, lake trout appear to be successfully recolonizing their native habitat. Adult stocks have built up significantly and are expanding their range in the lake. Preliminary investigations suggest that lake trout reproductive habitat is still adequate for natural reproduction, but natural recruitment has not been documented. Future assessments will be directed toward evaluation of spawning success and tracking age-class cohorts as they move through the fishery.

  5. Microbiology of Lonar Lake and other soda lakes

    Science.gov (United States)

    Paul Antony, Chakkiath; Kumaresan, Deepak; Hunger, Sindy; Drake, Harold L; Murrell, J Colin; Shouche, Yogesh S

    2013-01-01

    Soda lakes are saline and alkaline ecosystems that are believed to have existed throughout the geological record of Earth. They are widely distributed across the globe, but are highly abundant in terrestrial biomes such as deserts and steppes and in geologically interesting regions such as the East African Rift valley. The unusual geochemistry of these lakes supports the growth of an impressive array of microorganisms that are of ecological and economic importance. Haloalkaliphilic Bacteria and Archaea belonging to all major trophic groups have been described from many soda lakes, including lakes with exceptionally high levels of heavy metals. Lonar Lake is a soda lake that is centered at an unusual meteorite impact structure in the Deccan basalts in India and its key physicochemical and microbiological characteristics are highlighted in this article. The occurrence of diverse functional groups of microbes, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers and syntrophs in soda lakes, suggests that these habitats harbor complex microbial food webs that (a) interconnect various biological cycles via redox coupling and (b) impact on the production and consumption of greenhouse gases. Soda lake microorganisms harbor several biotechnologically relevant enzymes and biomolecules (for example, cellulases, amylases, ectoine) and there is the need to augment bioprospecting efforts in soda lake environments with new integrated approaches. Importantly, some saline and alkaline lake ecosystems around the world need to be protected from anthropogenic pressures that threaten their long-term existence. PMID:23178675

  6. Separated by sand, fused by dropping water: habitat barriers and fluctuating water levels steer the evolution of rock-dwelling cichlid populations in Lake Tanganyika.

    Science.gov (United States)

    Koblmüller, Stephan; Salzburger, Walter; Obermüller, Beate; Eigner, Eva; Sturmbauer, Christian; Sefc, Kristina M

    2011-06-01

    The conditions of phenotypic and genetic population differentiation allow inferences about the evolution, preservation and loss of biological diversity. In Lake Tanganyika, water level fluctuations are assumed to have had a major impact on the evolution of stenotopic littoral species, though this hypothesis has not been specifically examined so far. The present study investigates whether subtly differentiated colour patterns of adjacent Tropheus moorii populations are maintained in isolation or in the face of continuous gene flow, and whether the presumed influence of water level fluctuations on lacustrine cichlids can be demonstrated in the small-scale population structure of the strictly stenotopic, littoral Tropheus. Distinct population differentiation was found even across short geographic distances and minor habitat barriers. Population splitting chronology and demographic histories comply with our expectation of old and rather stable populations on steeper sloping shore, and more recently established populations in a shallower region. Moreover, population expansions seem to coincide with lake level rises in the wake of Late Pleistocene megadroughts ~100 KYA. The imprint of hydrologic events on current population structure in the absence of ongoing gene flow suggests that phenotypic differentiation among proximate Tropheus populations evolves and persists in genetic isolation. Sporadic gene flow is effected by lake level fluctuations following climate changes and controlled by the persistence of habitat barriers during lake level changes. Since similar demographic patterns were previously reported for Lake Malawi cichlids, our data furthermore strengthen the hypothesis that major climatic events synchronized facets of cichlid evolution across the East African Great Lakes. © 2011 Blackwell Publishing Ltd.

  7. A combination of bioleaching and electromagnetic separation in the treatment of quartz sands

    Directory of Open Access Journals (Sweden)

    Lovás Michal

    2006-12-01

    Full Text Available This contribution deals with the treatment of Slovakian eolic quartz sands by bioleaching and magnetic separation with the aim to remove iron. The X-ray study of sand patterns confirms that quartz occurs as a dominant mineral. Accompanying minerals are represented by smectite and feldspars. As to the sample of unground sand, bacterial leaching resulted in a Fe2O3 reduction to the content of 0.13 %. Similarly, in case of ground sample, the Fe2O3 content was decreased to the value of 0.19 %. Thus, biological leaching removed 60 % of Fe and by following leaching by oxalic acid total the iron removal was 70.5 %. Finally, the application of magnetic separation resulted in the total iron removal of 93 % and, in such combined way, the prepared product contained 0.024 % of Fe2O3. Achieved results on the iron removal points to the fact that the combination of leaching and magnetic separation enables to obtain a product usable in glass industry.

  8. Documenting the global impacts of beach sand mining

    Science.gov (United States)

    Young, R.; Griffith, A.

    2009-04-01

    For centuries, beach sand has been mined for use as aggregate in concrete, for heavy minerals, and for construction fill. The global extent and impact of this phenomenon has gone relatively unnoticed by academics, NGOs, and major news sources. Most reports of sand mining activities are found at the very local scale (if the mining is ever documented at all). Yet, sand mining in many localities has resulted in the complete destruction of beach (and related) ecosystems along with severe impacts to coastal protection and tourism. The Program for the Study of Developed Shorelines at Western Carolina University and Beachcare.org have initiated the construction of a global database of beach sand mining activities. The database is being built through a combination of site visits and through the data mining of media resources, peer reviewed papers, and reports from private and governmental entities. Currently, we have documented sand mining in 35 countries on 6 continents representing the removal of millions of cubic meters of sand. Problems extend from Asia where critical infrastructure has been disrupted by sand mining to the Caribbean where policy reform has swiftly followed a highly publicized theft of sand. The Program for the Study of Developed Shorelines recently observed extensive sand mining in Morocco at the regional scale. Tens of kilometers of beach have been stripped of sand and the mining continues southward reducing hope of a thriving tourism-based economy. Problems caused by beach sand mining include: destruction of natural beaches and the ecosystems they protect (e.g. dunes, wetlands), habitat loss for globally important species (e.g. turtles, shorebirds), destruction of nearshore marine ecosystems, increased shoreline erosion rates, reduced protection from storms, tsunamis, and wave events, and economic losses through tourist abandonment and loss of coastal aesthetics. The threats posed by sand mining are made even more critical given the prospect of a

  9. Studies on various characteristics of concrete structures using crushed sand

    International Nuclear Information System (INIS)

    Mimatsu, Makoto; Sugita, Hideaki; Yonemura, Masataka.

    1985-01-01

    With the recent advances of construction industry, the demands for concrete, hence for aggregate, are rising. The sand as such is in extreme shortage due to the exhaustion of river sand. Under the situation, the recent trends are for the use of crushed sand, i.e. the artificial sand obtained by crushing rocks, which have advantages of stabilized quality and adequate supplies. In building of nuclear power plants requiring large amounts of concrete, the usage of crushed sand is now unavoidable. The following are described : the situation of aggregate in Kyushu. production method of crushed sand and the quality standards, rocks used for crushed stone and sand and the properties, quality survey on crushed sand and the basic tests, characteristic tests of crushed-stone and -sand mixed concrete, the application of crushed sand in structures of the Sendai Nuclear Power Station. (Mori, K.)

  10. Ice-Dammed Lake Drainage Evolution at Russell Glacier, West Greenland

    Directory of Open Access Journals (Sweden)

    Jonathan L. Carrivick

    2017-11-01

    Full Text Available KEY POINTS/HIGHLIGHTSTwo rapid ice-dammed lake drainage events gauged and ice dam geometry measured.A melt enlargement model is developed to examine the evolution of drainage mechanism(s.Lake temperature dominated conduit melt enlargement and we hypothesize a flotation trigger.Glaciological and hydraulic factors that control the timing and mechanisms of glacier lake outburst floods (GLOFs remain poorly understood. This study used measurements of lake level at 15 min intervals and known lake bathymetry to calculate lake outflow during two GLOF events from the northern margin of Russell Glacier, west Greenland. We used measured ice surface elevation, interpolated subglacial topography and likely conduit geometry to inform a melt enlargement model of the outburst evolution. The model was tuned to best-fit the hydrograph rising limb and timing of peak discharge in both events; it achieved Mean Absolute Errors of <5%. About one third of the way through the rising limb, conduit melt enlargement became the dominant drainage mechanism. Lake water temperature, which strongly governed the enlargement rate, preconditioned the high peak discharge and short duration of these floods. We hypothesize that both GLOFs were triggered by ice dam flotation, and localized hydraulic jacking sustained most of their early-stage outflow, explaining the particularly rapid water egress in comparison to that recorded at other ice-marginal lakes. As ice overburden pressure relative to lake water hydraulic head diminished, flow became confined to a subglacial conduit. This study has emphasized the inter-play between ice dam thickness and lake level, drainage timing, lake water temperature and consequently rising stage lake outflow and flood evolution.

  11. A previously unrecognized path of early Holocene base flow and elevated discharge from Lake Minong to Lake Chippewa across eastern Upper Michigan

    Science.gov (United States)

    Loope, Walter L.; Jol, Harry M.; Fisher, Timothy G.; Blewett, William L.; Loope, Henry M.; Legg, Robert J.

    2014-01-01

    It has long been hypothesized that flux of fresh meltwater from glacial Lake Minong in North America's Superior Basin to the North Atlantic Ocean triggered rapid climatic shifts during the early Holocene. The spatial context of recent support for this idea demands a reevaluation of the exit point of meltwater from the Superior Basin. We used ground penetrating radar (GPR), foundation borings from six highway bridges, a GIS model of surface topography, geologic maps, U.S. Department of Agriculture–Natural Resources Conservation Service soils maps, and well logs to investigate the possible linkage of Lake Minong with Lake Chippewa in the Lake Michigan Basin across eastern Upper Michigan. GPR suggests that a connecting channel lies buried beneath the present interlake divide at Danaher. A single optical age hints that the channel aggraded to 225 m as elevated receipt of Lake Agassiz meltwater in the Superior Basin began to wane GIS model of Minong's shoreline are consistent with another transgression of Minong after ca. 9.5 ka. At the peak of the latter transgression, the southeastern rim of the Superior Basin (Nadoway Drift Barrier) failed, ending Lake Minong. Upon Minong's final drop, aggradational sediments were deposited at Danaher, infilling the prior breach.

  12. Investigation of Lake Water Salinity by Using Four-Band Salinity Algorithm on WorldView-2 Satellite Image for a Saline Industrial Lake

    Science.gov (United States)

    Budakoǧlu, Murat; Karaman, Muhittin; Damla Uça Avcı, Z.; Kumral, Mustafa; Geredeli (Yılmaz), Serpil

    2014-05-01

    Salinity of a lake is an important characteristic since, these are potentially industrial lakes and the degree of salinity can significantly be used for determination of mineral resources and for the production management. In the literature, there are many studies of using satellite data for salinity related lake studies such as determination of salinity distribution and detection of potential freshwater sources in less salt concentrated regions. As the study area Lake Acigol, located in Denizli (Turkey) was selected. With it's saline environment, it's the major sodium sulphate production resource of Turkey. In this study, remote sensing data and data from a field study was used and correlated. Remote sensing is an efficient tool to monitor and analyze lake properties by using it complementary to field data. Worldview-2 satellite data was used in this study which consists of 8 bands. At the same time with the satellite data acquisition, a field study was conducted to collect the salinity values in 17 points of the laker with using YSI 556 Multiparametre for measurements. The values were measured as salinity amount in grams per kilogram solution and obtained as ppt unit. It was observed that the values vary from 34 ppt - 40.1 ppt and the average is 38.056 ppt. In Thalassic serie, the lake was in mixoeuhaline state in the time of issue. As a first step, ATCOR correction was performed on satellite image for atmospheric correction. There were some clouds on the lake field, hence it was decided to continue the study by using the 12 sampling points which were clear on the image. Then, for each sampling point, a spectral value was obtained by calculating the average at a 11*11 neighborhood. The relation between the spectral reflectance values and the salinity was investigated. The 4-band algorithm, which was used for determination of chlorophyll-a distribution in highly turbid coastal environment by Wei (2012) was applied. Salinity α (Λi-1 / Λj-1) * (Λk-1 / Λm-1) (i

  13. Eutrophication status and control strategy of Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    Limin ZHANG; Minfang XIA; Lei ZHANG; Chun WANG; Jilai LU

    2008-01-01

    The water quality and eutrophication status of Taihu Lake in recent years are presented and the pollution trends are analyzed. It is shown that because of unreas-onable industrial structures, pollution discharge per GDP is high within the Taihu basin, and the pollution discharge from point and-non-point sources exceed the basin's environmental carrying capacity. Especially, excessive pollutants containing nitrgogen and phosphorus are being discharged. Moreover, eutrophication may also result from internal pollution sources such as the release of nutrient elements from sediment. All these factors have resulted in-the water quality deterioration of Taihu Lake. To solve this environmental problem, possible con-trol strategies are summarized, including the control of internal pollution sources and inflow-river pollution, eco-logical restoration and reconstruction of the degraded lakeside zone ecosystem, clean water diversion, dredging, and manual algae removal.

  14. Mud-farming of fine oil sands tailings

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Y.; Tol van, F.; Paassen van, L.; Everts, B.; Mulder, A. [Delft Univ. of Technology, Delft (Netherlands). Dept. of Geotechnology

    2010-07-01

    This PowerPoint presentation discussed an experimental mud-farming technique for fine oil sands tailings. The technique was based on a sub-areal drying technique for dredging sludge developed in the Netherlands for Rotterdam harbour sediments. Between 1960 and 1985, the sludge was deposited in confined disposal sites on land. The sludge was converted to usable clay between 1970 and 1980. The polluted portion of the sludge is stored in a man-made disposal site. The sludge was deposited in thin layers. Stagnant water was then removed. The mud was then dewatered and reused. The sludge was furrowed with amphirol and disc wheels in order to accelerate the ripening process. The dredged material was re-used in a clay factory. The technique was applied to oil sands tailings in order to understand the suction behaviour, sedimentation behaviour, and precipitation deficit of the tailings. State changes of the sludge were monitored. No clear sedimentation phase was identified prior to consolidation. A comparison of material properties showed that the total amount of water to be extracted was more than the Rotterdam sludge, but the suction behaviour was similar. The precipitation deficit from mid-April until September will require a customized deposition strategy. Details and photographs of the experimental studies were included. tabs., figs.

  15. Influence of sand base preparation on properties of chromite moulding sands with sodium silicate hardened with selected methods

    Directory of Open Access Journals (Sweden)

    Stachowicz M.

    2017-03-01

    Full Text Available The paper presents a research on the relation between thermal preparation of chromite sand base of moulding sands containing sodium silicate, hardened with selected physical and chemical methods, and structure of the created bonding bridges. Test specimens were prepared of chromite sand - fresh or baked at 950°C for 10 or 24 hours - mixed with 0.5 wt.% of the selected non-modified inorganic binder and, after forming, were hardened with CO2 or liquid esters, dried traditionally or heated with microwaves at 2.45 GHz. It was shown on the grounds of SEM observations that the time of baking the base sand and the hardening method significantly affect structure of the bonding bridges and are correlated with mechanical properties of the moulding sands. It was found that hardening chromite-based moulding mixtures with physical methods is much more favourable than hardening with chemical methods, guaranteeing also more than ten times higher mechanical properties.

  16. The role of Lake Dongting in regulating the sediment budget of the Yangtze River

    Directory of Open Access Journals (Sweden)

    Shi-bao Dai

    2005-01-01

    Full Text Available Lake Dongting, the second largest freshwater lake in China and located in the middle reaches of the River Yangtze catchment, was formed at the beginning of the Holocene period by sea level rise and has varied in size with changes in local weather patterns. The sedimentation rate in Lake Dongting during the Holocene is about 50×106 m3 yr-1, or 80×106 t yr-1 (a sand bulk density of 1.6×103 kg m-3, given the sediment deposition rate as 10 mm yr-1 and the average lake size as 5000 km2. By comparing the sediment import and export, it is estimated that the sediment deposition rate of Lake Dongting was 110.6×106 t yr-1 from 1956 to 2003. Siltation and raised embankments reduced the size of the lake and its capacity to accommodate floods. The sediment delivery ratio (SDR of the middle and lower Yangtze is about 0.92 (total sediment output divided by total sediment input given that the total sediment supply into the middle and lower Yangtze is 455.1×106 t yr-1 and the total sediment discharge into the sea is 419×106 t yr-1. Therefore, if it were not for Lake Dongting, the sediment flux at Datong would be 73.6×106 t yr-1 (80×106 t yr-1×0.92 more, an increase of 27% during the Holocene and an increase of 26% to 101.75×106 t yr-1 from 1956 to 2003. Historically, Lake Dongting had a considerable influence in regulating the sediment budget of the Yangtze. However, afforestation and the construction of large dams, such as the Three Gorges Dam, reduced significantly the sediment deposition in Lake Dongting. In 2003, the completion of the Three Gorges Dam and the subsequent impoundment of water reduced the sediment input from the Yangtze and net deposition in Lake Dongting dropped to 25% and 18% of the mean values of the historic records (1956-2003. During the same period, the amount of sediment deposited in Lake Dongting was only 10% of the sediment discharge at Datong. The influence of the sediment deposited in Lake Dongting on the sediment flux to

  17. Experimental perforation of tubing with a hydraulic sand jet

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, Yu V

    1970-01-01

    A series of field tests has shown that perforation with a hydraulic sand jet improves the quality of well completion. The sand jet does not crack the cement sheath or the casing, and the perforations are larger and deeper than perforations formed by explosive charges. Fluid circulation during sand jet perforation can safely be stopped for at least 10 min. Water containing a surfactant can be used as a sand carrier. Sand jet perforation allows successful completion of wells cased by 2 tubing strings. Sand jet perforation can be used to clean the borehole well and to remove foreign objects from the well.

  18. Great Lakes rivermouth ecosystems: scientific synthesis and management implications

    Science.gov (United States)

    Larson, James H.; Trebitz, Anett S.; Steinman, Alan D.; Wiley, Michael J.; Carlson Mazur, Martha; Pebbles, Victoria; Braun, Heather A.; Seelbach, Paul W.

    2013-01-01

    At the interface of the Great Lakes and their tributary rivers lies the rivermouths, a class of aquatic ecosystem where lake and lotic processes mix and distinct features emerge. Many rivermouths are the focal point of both human interaction with the Great Lakes and human impacts to the lakes; many cities, ports, and beaches are located in rivermouth ecosystems, and these human pressures often degrade key ecological functions that rivermouths provide. Despite their ecological uniqueness and apparent economic importance, there has been relatively little research on these ecosystems as a class relative to studies on upstream rivers or the open-lake waters. Here we present a synthesis of current knowledge about ecosystem structure and function in Great Lakes rivermouths based on studies in both Laurentian rivermouths, coastal wetlands, and marine estuarine systems. A conceptual model is presented that establishes a common semantic framework for discussing the characteristic spatial features of rivermouths. This model then is used to conceptually link ecosystem structure and function to ecological services provided by rivermouths. This synthesis helps identify the critical gaps in understanding rivermouth ecology. Specifically, additional information is needed on how rivermouths collectively influence the Great Lakes ecosystem, how human alterations influence rivermouth functions, and how ecosystem services provided by rivermouths can be managed to benefit the surrounding socioeconomic networks.

  19. Effect of manufactured sand on the durability characteristics of concrete

    Directory of Open Access Journals (Sweden)

    S. S. SARAVANAN

    2016-12-01

    Full Text Available Concrete is the most sought after material due to increase in construction activities and infrastructural developments. Availability of natural sand is decreasing thereby increase in the cost of construction. In the present work undertaken, an attempt has been made to give an alternative to natural sand. Optimization of replacement of natural sand with manufactured sand in concrete, durability studies such as water absorption, rapid chloride permeability test, sorptivity, acid resistance, alkaline resistance, impact resistance and abrasion resistance of M40 and M50 grades of concrete have been studied with manufactured sand as fine aggregate and compared the results with the conventional sand concrete. The results shows that there is an increase in the durability properties up to 70 % level of replacements of sand with manufactured sand as fine aggregate and for 100 % use of manufactured sand also gives the better durability than the conventional sand concrete.

  20. Relict sand waves in the continental shelf of the Gulf of Valencia (Western Mediterranean)

    Science.gov (United States)

    Albarracín, Silvia; Alcántara-Carrió, Javier; Montoya-Montes, Isabel; Fontán-Bouzas, Ángela; Somoza, Luis; Amos, Carl L.; Salgado, Jorge Rey

    2014-10-01

    The presence of fossil or relict bedforms is common in the Quaternary fill of modern continental shelf due to sea level oscillations, tectonic subsidence and migration of associated sedimentary facies. The continental margin of the Gulf of Valencia has been strongly influenced by glacio-eustasy and neotectonics. High-resolution multibeam bathymetry data, seismic reflection profiles and box core samples were collected across the continental shelf of the Gulf of Valencia during the DERIVA cruises carried out in 2010 and 2011. The integrated analysis of this data set and high-resolution mapping of the relict bedforms on the Valencian continental shelf, ranging between 50 and 90 m allowed the study of previously identified system of sand waves located in front of the present-day Albufera de Valencia lagoon. The system is composed of 27 ridges with a NNE-SSW orientation, i.e. oblique to the present shoreline, in which the lateral horns point backwards. These sand waves can reach 10 m in height and 3 km in length resulting in a maximum slope of 6°. According to seismic stratigraphic and relative sea level curve reconstructions, these sand waves were formed during the Younger Dryas (~ 12-10 ky BP). Consequently, they have been classified as Holocene sand waves associated with coastal sedimentary evolution.

  1. Experimental Study on Superfine Sand Concrete Mixed by Double Mixing Technology

    OpenAIRE

    yuqing zhao

    2013-01-01

    Traditional concept thought that medium sand and fine sand can be used to mix concrete, superfine sand can not used to mix concrete. This makes the source of superfine sand limited. With the shortage of medium sand and fine sand, it is imperative to exploit the resource of superfine sand. Superfine sand concrete is mixed by means of Double-doped Technology-ultra-fine fly ash and super plasticizer. Primary factor influencing superfine sand concrete strength is studied by orthogonal test, the o...

  2. Effects of irrigation on streamflow in the Central Sand Plain of Wisconsin

    Science.gov (United States)

    Weeks, E.P.; Stangland, H.G.

    1971-01-01

    Development of ground water for irrigation affects streamflow and water levels in the sand-plain area of central Wisconsin. Additional irrigation development may reduce opportunities for water-based recreation by degrading the streams as trout habitat and by lowering lake levels. This study was made to inventory present development of irrigation in the sand-plain area, assess potential future development, and estimate the effects of irrigation on streamflow and ground-water levels. The suitability of land and the availability of ground water for irrigation are dependent, to a large extent, upon the geology of the area. Rocks making up the ground-water reservoir include outwash, morainal deposits, and glacial lake deposits. These deposits are underlain by crystalline rocks and by sandstone, which act as the floor of the ground-water reservoir. Outwash, the main aquifer, supplies water to about 300 irrigation wells and maintains relatively stable flow in the streams draining the area. The saturated thickness of these deposits is more than 100 feet over much of the area and is as much as 180 feet in bedrock valleys. The saturated thickness of the outwash generally is great enough to provide sufficient water for large-scale irrigation in all but two areas --one near the town of Wisconsin Rapids and one near Dorro Couche Mound. Aquifer tests indicate that the permeability of the outwash is quite high, ranging from about 1,000 gpd per square foot to about 3,800 gpd per square foot, Specific capacities of irrigation wells in the area range from 14 to 157 gpm per foot of drawdown. Water use in the sand-plain area is mainly for irrigation and waterbased recreation. Irrigation development began in the area in the late 1940's, and by 1967 about 19,500 acre-feet of water were pumped to irrigate 34,000 acres of potatoes, snap beans, corn, cucumbers, and other crops. About 70 percent of the applied water was lost to evapotranspiration, and about 30 percent was returned to the

  3. The physics of wind-blown sand and dust.

    Science.gov (United States)

    Kok, Jasper F; Parteli, Eric J R; Michaels, Timothy I; Karam, Diana Bou

    2012-10-01

    The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This paper presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.

  4. Holocene Lake-Level Fluctuations of Lake Aricota, Southern Peru

    Science.gov (United States)

    Placzek, Christa; Quade, Jay; Betancourt, Julio L.

    2001-09-01

    Lacustrine deposits exposed around Lake Aricota, Peru (17° 22‧S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (<350 yr). Diatomites associated with highstands several meters above the modern lake level indicate wet episodes. Maximum Holocene lake level was attained before 6100 14C yr B.P. and ended ∼2700 14C yr B.P. Moderately high lake levels occurred at 1700 and 1300 14C yr B.P. The highstand at Lake Aricota during the middle Holocene is coeval with a major lowstand at Lake Titicaca (16°S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes.

  5. Sand Dunes with Frost

    Science.gov (United States)

    2004-01-01

    9 May 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a suite of frost-covered sand dunes in the north polar region of Mars in early spring, 2004. The dunes indicate wind transport of sand from left to right (west to east). These landforms are located near 78.1oN, 220.8oW. This picture is illuminated by sunlight from the lower left and covers an area about 3 km (1.9 mi) across.

  6. Relationships between sand and water quality at recreational beaches.

    Science.gov (United States)

    Phillips, Matthew C; Solo-Gabriele, Helena M; Piggot, Alan M; Klaus, James S; Zhang, Yifan

    2011-12-15

    Enterococci are used to assess the risk of negative human health impacts from recreational waters. Studies have shown sustained populations of enterococci within sediments of beaches but comprehensive surveys of multiple tidal zones on beaches in a regional area and their relationship to beach management decisions are limited. We sampled three tidal zones on eight South Florida beaches in Miami-Dade and Broward counties and found that enterococci were ubiquitous within South Florida beach sands although their levels varied greatly both among the beaches and between the supratidal, intertidal and subtidal zones. The supratidal sands consistently had significantly higher (p sand) than the other two zones. Levels of enterococci within the subtidal sand correlated with the average level of enterococci in the water (CFU/100mL) for the season during which samples were collected (r(s) = 0.73). The average sand enterococci content over all the zones on each beach correlated with the average water enterococci levels of the year prior to sand samplings (r(s) = 0.64) as well as the average water enterococci levels for the month after sand samplings (r(s) = 0.54). Results indicate a connection between levels of enterococci in beach water and sands throughout South Florida's beaches and suggest that the sands are one of the predominant reservoirs of enterococci impacting beach water quality. As a result, beaches with lower levels of enterococci in the sand had fewer exceedences relative to beaches with higher levels of sand enterococci. More research should focus on evaluating beach sand quality as a means to predict and regulate marine recreational water quality. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Compressive Strength of Compacted Clay-Sand Mixes

    Directory of Open Access Journals (Sweden)

    Faseel Suleman Khan

    2014-01-01

    Full Text Available The use of sand to improve the strength of natural clays provides a viable alternative for civil infrastructure construction involving earthwork. The main objective of this note was to investigate the compressive strength of compacted clay-sand mixes. A natural clay of high plasticity was mixed with 20% and 40% sand (SP and their compaction and strength properties were determined. Results indicated that the investigated materials exhibited a brittle behaviour on the dry side of optimum and a ductile behaviour on the wet side of optimum. For each material, the compressive strength increased with an increase in density following a power law function. Conversely, the compressive strength increased with decreasing water content of the material following a similar function. Finally, the compressive strength decreased with an increase in sand content because of increased material heterogeneity and loss of sand grains from the sides during shearing.

  8. The diversity of benthic mollusks of Lake Victoria and Lake Burigi ...

    African Journals Online (AJOL)

    Molluscan diversity, abundance and distribution in sediments of Lake Victoria and its satellite lake, Lake Burigi, were investigated. The survey was carried out in January and February 2002 for Lake Victoria and in March and April 2002 for Lake Burigi. Ten genera were recorded from four zones of Lake Victoria while only ...

  9. Controls on the abruptness of gravel-sand transitions

    Science.gov (United States)

    Venditti, J. G.; Church, M. A.; Lamb, M. P.; Domarad, N.; Rennie, C. D.

    2014-12-01

    As gravel-bedded rivers fine downstream, they characteristically exhibit an abrupt transition from gravel- to sand-bed. This is the only abrupt transition in grain-size that occurs in the fluvial system and has attracted considerable attention. A number of competing theories have been proposed to account for the abruptness of the transition, including base-level control, attrition of ~10mm gravel to produce sand, and sediment sorting processes. The prevailing theory for the emergence of abrupt transitions is size selective sorting of bimodal sediment wherein gravel deposits due to downstream declining shear stress, fining the bedload until a sand-bed emerges. We explored this hypothesis by examining grain-size, shear stress, gravel mobility and sand suspension thresholds through the gravel-sand transition (GST) of the Fraser River, British Columbia. The Fraser GST is an arrested gravel wedge with patches of gravel downstream of the wedge forming a diffuse extension. There is an abrupt change in bed slope through the transition that leads to an abrupt change in shear stress. The GST, bed-slope change and backwater caused by the ocean are all coincident spatially, which enhances the sharpness of the GST. Interestingly, the bimodal reach of the river occurs downstream of the GST and exhibits no downstream gradients in shear stress, suspended sediment flux, gravel mobility or sand suspension thresholds. This calls into question the prevailing theory for the emergence of an abrupt GST by size selective sorting. We provide evidence, both empirical and theoretical, that suggests the emergence of an abrupt GST is caused by rapid deposition of sand when fine gravel deposits. We argue that the emergence of gravel-sand transitions is a consequence of gravel-bedded rivers adopting a steeper slope than sand-bedded rivers. The abruptness arises because the bed slope required to convey the gravel load fixes the distal location of a terminal gravel wedge, and once the river has

  10. Lake Morphometry for NHD Lakes in Great Lakes Region 4 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  11. Oil sands to the rescue: oil sand microbial communities can degrade recalcitrant alkyl phenyl alkanoic acids

    Energy Technology Data Exchange (ETDEWEB)

    Whitby, Corinne [University of Essex (Canada)], email: cwhitby@essex.ac.uk

    2011-07-01

    Almost half of all global oil reserves are found as biodegraded heavy oils found in vast tar sand deposits located in North and South America and these account for 47% of Canadian oil production. Oil sand extraction generates large amounts of toxic waste water, known as oil sand process waters (OSPW), that are stored in large tailing ponds that contain toxic compounds like naphthenic acids (NAs). The presence of NAs creates problems like toxicity, corrosion, and the formation of calcium napthenate deposits which block pipelines and other infrastructure and need to be removed. This paper presents oil sand microbial communities that can degrade these NAs. The approach is to apply new aliphatic and aromatic NAs as substrates to supplement and identify NA degrading microbes and also to identify the metabolites produced and explain NA degradation pathways and the functional genes involved. The chemistry and the processes involved are explained. From the results, it is suggested that pure cultures of P. putida KT2440 be used against NAs.

  12. sand_point.grd

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC builds and distributes high-resolution, coastal digital elevation models (DEMs) that integrate ocean bathymetry and land topography to support NOAA's mission to...

  13. Habitat Preferences and Distribution of the Freshwater Shrimps of the Genus Caridina (Crustacea: Decapoda: Atyidae in Lake Lindu, Sulawesi, Indonesia

    Directory of Open Access Journals (Sweden)

    Annawaty Annawaty

    2016-04-01

    Full Text Available The objectives of this study were to reveal ecological preferences and distribution of all species of Caridina found in Lake Lindu and their catchment area. Specimens from 39 sampling sites were caught using tray net and hand net. There are three species of Caridina found in the lake system, i.e. Caridina linduensis, Caridina kaili and Caridina dali. There is no overlapping distribution among the species. Caridina kaili is a true riverine species and it is never encountered sympatric with C. dali nor C. linduensis. This species is abundant in streams and ditches with moderate flow running water and gravel–cobble substrate. It is mainly spread within streams west to the lake. Both C. dali and C. linduensis can be found in the lake and streams with very slow current to almost stagnant water, muddy sand substrate and associated with roots of water plants and leaf litter. However, C. dali is never occurred together with C. linduensis and they are less abundant compare to C. kaili. Distribution of Caridina spp. in Lake Lindu is probably affected by the temperature of their habitats and the occurrence of introduced fish such as Mozambique tilapia (Oreochromis mossambicus, common carp (Cyprinus carpio, and an alien riceland prawn (Macrobrachium lanchesteri. These introduced and alien species can have the potency to become predators or competitors for the Caridina spp. It is also the first record for M. lanchesteri present in Lake Lindu.

  14. Potential building sand deposits in Songkhla province area

    Directory of Open Access Journals (Sweden)

    Kooptarnond, K.

    2002-10-01

    Full Text Available An investigation of potential building sand deposits in Songkhla province area subdivided them into four regions according to their accumulation in various alluvial plains, meanders throughout alluvial deposits and residual soils. Four selected deposits, were Rattaphum-Khuan Niang, U-Taphao river, Na Mom, and Chana-Thepha regions. Information obtained from these deposits revealed a good correlation between the geomorphological features as interpreted from aerial photographs and those identified from vertical electrical resistivity sounding results. Sand samples were analysed for their physical and chemical properties. Petrographic studies were also undertaken to characterize the composition types, texture and shapes. An overview of the sand properties was used them to be within the acceptable limits for building sand. However, relatively high organic impurities and soundness were found in sand from Khuan Niang and Na Mom deposits. The result indicated a potential reconnaissance mineral resource of about 46 square kilometres.A reserve evaluation for natural building sand was carried out by using Geographic Information System (GIS. Maps of the various parameters considered were constructed in digital database format with the aid of Arc/Info and ArcView software. Overlay mapping and buffer zone modules were performed to evaluate inferred resources of building sand. The key parameters of analysis included the distance from transportation, distance from streams, lithology and thickness of sand layers. The remaining inferred sand total was of about 386 million cubic metres or about 1,021 million metric tons was therefore estimated, of which 60 percent lies in the Rattaphum-Khuan Niang region and 40 percent in the other regions.

  15. Water-quality data for aquifers, streams, and lakes in the vicinity of Keechi, Mount Sylvan, Oakwood, and Palestine salt domes, northeast Texas salt-dome basin

    International Nuclear Information System (INIS)

    Carr, J.E.; Halasz, S.J.; Liscum, F.

    1980-11-01

    This report contains water-quality data for aquifers, streams, and lakes in the vicinity of Keechi, Mount Sylvan, Oakwood, and Palestine Salt Domes in the northeast Texas salt-dome basin. Water-quality data were compiled for aquifers in the Wilcox Group, the Carrizo Sand, and the Queen City Sand. The data include analyses for dissolved solids, pH, temperature, hardness, calcium, magnesium, sodium, bicarbonate, chloride, and sulfate. Water-quality and streamflow data were obtained from 63 surface-water sites in the vicinity of the domes. These data include water discharge, specific conductance, pH, water temperature, and dissolved oxygen. Samples were collected at selected sites for analysis of principal and selected minor dissolved constituents

  16. Geophysical Investigation of a Thermokarst Lake Talik in Continuous Permafrost

    Science.gov (United States)

    Creighton, A.; Parsekian, A.; Arp, C. D.; Jones, B. M.; Babcock, E.; Bondurant, A. C.

    2016-12-01

    On the Arctic Coastal Plain (ACP) of northern Alaska, shallow thermokarst lakes cover up to 25% of the landscape. These lakes occupy depressions created by the subsidence of thawed, ice-rich permafrost. Areas of unfrozen sediment, or taliks, can form under lakes that have a mean annual bottom temperature greater than 0°C. The geometry of these taliks, as well as the processes that create them, are important for understanding interactions between surface water, groundwater, and carbon cycling. Non-invasive geophysical methods are a useful means to study talik sediments as borehole studies yield few data points, and the contrast between unfrozen and frozen sediments is an ideal geophysical target. To study talik configuration associated with an actively expanding thermokarst lake, we conducted a geophysical transect across Peatball Lake. This lake has an estimated initiation age of 1400 calendar years BP. Over the past 60 years, lake surface area has increased through thermal and mechanical shoreline erosion. A talik of previously unknown thickness likely exists below Peatball Lake. We conducted a transect of transient electromagnetic soundings across the lake extending into the surrounding terrestrial environment. Since permafrost has relatively high resistivity compared to talik sediments, the interpreted electrical structure of the subsurface likely reflects talik geometry. We also conducted nuclear magnetic resonance soundings at representative locations along the transect. These measurements can provide data on sub-lake sediment properties including water content. Together, these measurements resolve the talik structure across the lake transect and showed evidence of varying talik thicknesses from the lake edge to center. These is no evidence of a talik at the terrestrial control sites. These results can help constrain talik development models and thus provide insight into Arctic and permafrost processes in the face of a changing climate.

  17. Stakeholder relations in the oil sands : managing uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-05-15

    Alberta's oil sands are now at the crossroads of a series of significant and complex global issues that will require careful negotiation by all stakeholders involved in the oil sands industry. This paper discussed methods of managing uncertainty and risk related to the oil sands industry's agenda for the future. Oil sands developers must continue to secure permission from communities and other key stakeholders in order to develop oil sand projects. Stakeholder relations between oil sands operators, First Nations, and Metis Nation communities must ensure that respect is maintained while environmental impacts are minimized and long-term economic benefits are secured for all parties. Environmental non-governmental organizations (ENGOs) must ensure that oil sands resources are developed responsibly, and that environmental standards are maintained. Seven key shifts in stakeholder relations resulting from the recent economic crisis were identified. These included (1) withdrawal from the multi-stakeholder process, (2) increased focus on government to demonstrate policy leadership, (3) a stronger push from ENGOs to express environmental concerns, (4) global lobby and public relations efforts from ENGOs, (5) companies retreating to local community stakeholders, (6) more active demands from First Nations and Metis Nations groups, and (7) companies challenging ENGO campaigns. The study concluded by suggesting that government leadership is needed to clear policy and regulatory frameworks for Canada's oil sands.

  18. Providing floating capabilities in latest-generation sand screens

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, E.G.; Coronado, M.P. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Baker Hughes, Houston, TX (United States)

    2008-10-15

    Alternative production methods are needed for the massive reserves located in the bitumen region of Canada's tar sands. The area has over 100 installations of sand screens/slotted liners in both injection and production legs using steam-assisted gravity drainage (SAGD) technology. Multiple wells must be drilled from a single pad because of the sensitive nature of the environment. With significant depths of these wells, a floating sand screen provides assurance that the sand screen will reach the desired depth. Paraffin is generally used to plug the flow access of the screen during installation. This paper discussed a new technology that has been developed to allow for sand screen installations without relying on paraffin wax to withstand differential pressure. The new technology uses a hydro-mechanical valving system incorporated into the screen design to temporarily close off the screen while being run in the hole. The paper described how the technology could provide a reliable, time-saving solution for SAGD installations when floating sand control screens are needed. The paper discussed current technology and its limitations, sand screen installation, screen design for floating applications, and additional applications. It was concluded that this technology solution provides a unique alternative to the methods currently used to install sand screens with SAGD technology in the fast growing Canadian market for bitumen recovery. 2 refs., 5 figs.

  19. Anthropopression markers in lake bottom sediments

    Science.gov (United States)

    Nadolna, Anna; Nowicka, Barbara

    2014-05-01

    Lakes are vulnerable to various types of anthropogenic disturbances. Responses of lake ecosystems to environmental stressors are varied and depend not only on the type of a factor but also on the lake natural resistance to degradation. Within the EULAKES project an evaluation of anthropogenic stress extent in a flow-through, postglacial, ribbon lake (Lake Charzykowskie) was carried out. It was assumed, that this impact manifests unevenly, depending on a type and degree of the pressure on the shore zones, water quality of tributaries, lake basin shape and dynamics of a water movement. It was stated, that anthropogenic markers are substances accumulated in bottom sediments as a result of allochthonous substances inflow from the catchment and atmosphere. Along the selected transects 105 samples from the top layer of sediments (about 20 cm) was collected representing the contemporary accumulation (about 15 years). The content of selected chemical elements and compounds was examined, including nutrients (TN and TP), heavy metals (arsenic, cadmium, lead, chromium, nickel, copper, zinc, mercury, iron, and manganese) and pesticides (DDT, DDD, DDE, DMDT , γ-HCH). The research was conducted in the deepest points of each lake basin and along the research transects - while choosing the spots, the increased intensity of anthropogenic impact (ports, roads with heavy traffic, wastewater discharge zones, built-up areas) was taken into consideration. The river outlets to the lake, where there are ecotonal zones between limnic and fluvial environment, were also taken into account. Analysis of the markers distribution was carried out against the diversity of chemical characteristics of limnic sediments. Ribbon shape of the lake basin and the dominant wind direction provide an opportunity of easy water mixing to a considerable depth. Intensive waving processes cause removal of the matter from the littoral zone towards lake hollows (separated by the underwater tresholds), where the

  20. A qualitative evaluation of long-term processes governing the behaviour of uranium mill tailings placed in deep lakes

    International Nuclear Information System (INIS)

    McKee, Paul; Snodgrass, William; Lush, D.L.; Ross, P.

    1982-03-01

    The emplacement of uranim mill tailings in deep lakes may provide an acceptable method of tailings disposal at certain sites in Canada. Disposal in a depositional environment typical of deep lakes appears to offer greater prospects for long-term stability than present methods of land-based management. From the regulatory point of view, it is necessary to know which factors should be taken into account in assessing the acceptability of such an approach. This report examines the environmental variables governing the behaviour of radionuclides and trace elements in the groundwater systems, lake water, and finally in the biosphere over the short and long-term. Physical, chemical and biological factors are each considered. Conclusions are presented in terms of points for and against disposal in deep lakes

  1. Spatial and temporal genetic diversity of lake whitefish (Coregonus clupeaformis (Mitchill)) from Lake Huron and Lake Erie

    Science.gov (United States)

    Stott, Wendylee; Ebener, Mark P.; Mohr, Lloyd; Hartman, Travis; Johnson, Jim; Roseman, Edward F.

    2013-01-01

    Lake whitefish (Coregonus clupeaformis (Mitchill)) are important commercially, culturally, and ecologically in the Laurentian Great Lakes. Stocks of lake whitefish in the Great Lakes have recovered from low levels of abundance in the 1960s. Reductions in abundance, loss of habitat and environmental degradation can be accompanied by losses of genetic diversity and overall fitness that may persist even as populations recover demographically. Therefore, it is important to be able to identify stocks that have reduced levels of genetic diversity. In this study, we investigated patterns of genetic diversity at microsatellite DNA loci in lake whitefish collected between 1927 and 1929 (historical period) and between 1997 and 2005 (contemporary period) from Lake Huron and Lake Erie. Genetic analysis of lake whitefish from Lakes Huron and Erie shows that the amount of population structuring varies from lake to lake. Greater genetic divergences among collections from Lake Huron may be the result of sampling scale, migration patterns and demographic processes. Fluctuations in abundance of lake whitefish populations may have resulted in periods of increased genetic drift that have resulted in changes in allele frequencies over time, but periodic genetic drift was not severe enough to result in a significant loss of genetic diversity. Migration among stocks may have decreased levels of genetic differentiation while not completely obscuring stock boundaries. Recent changes in spatial boundaries to stocks, the number of stocks and life history characteristics of stocks further demonstrate the potential of coregonids for a swift and varied response to environmental change and emphasise the importance of incorporating both spatial and temporal considerations into management plans to ensure that diversity is preserved.

  2. Revegetation and management of tailings sand slopes from tar sand extraction: 1978 results

    Energy Technology Data Exchange (ETDEWEB)

    Rowell, M J

    1979-01-01

    The results are reported of research into the revegetation of two areas on a steeply sloping dike composed of tailings sand from tar sand extraction at the Great Canadian Oil Sand Limited plant at Fort McMurray, Alberta. One area was seeded with three pasture grasses and two legumes in 1971 after the slope surface had been mixed with peat to a depth of 15 cm. A second area had been amended with peat or peat and overburden and differing rates of fertilizer added. A mix containing nine grasses, four legumes, and oats, as a companion crop, was seeded in July 1976. The objectives of the research were to study methods for the establishment of a stable vegetative cover that would prevent erosion of the slope and, in time, might become a self maintaining unit. Tillage of soil amendments to a depth of 15 cm and 30 cm were compared in promoting deeper rooting and stabilizing of the slope.

  3. Developing new markets for oil sands products

    International Nuclear Information System (INIS)

    Crandall, G.

    2004-01-01

    This paper presents a review by Purvin and Gertz of western Canadian crude oil supply. This energy consulting firm provides advise to the energy sector. It suggests that oil sands production will surpass declining conventional production. Oil sands supply includes bitumen, synthetic crude oil (SCO), and diluent. It is forecasted that oil sands will increase from 42 per cent of western supply in 2002 to 78 per cent in 2015. The potential of Alberta's oil sands was discussed along with a recent study of refined products and petrochemicals from bitumen. Upgrading, refining and petrochemical case studies were presented. The author examined if a Canadian oil sands upgrading project with high capital costs can be competitive with competing projects in the United States and internationally. In addition to supply and demand issues, the presentation examined infrastructure capability and market potential in the United States. The economic potential and risks of preferred business cases compared to upgrading to SCO were also evaluated. 15 figs

  4. The behavior of gaseous iodine in sand

    International Nuclear Information System (INIS)

    Takahashi, Kanji

    1974-01-01

    Radioactive iodine gas was passed through 10 different sands collected at rivers and hills. The relation between the amount of the loaded gas and the amount of adsorbed gas was determined at room temperature, 50 -- 60 0 C, and 90 -- 100 0 C under humidity of 2 sand. This amount was about 1 -- 3 times as much as that of monomolecular membrane adsorption, 0.2 -- 0.3 μg/cm 2 . The decrease of adsorption amount that accompanies the increase of humidity is attributable to the decrease of effective surface area of sand due to the presence of water. The transport of iodine in sand was studied by passing gaseous iodine through a glass tubing packed with sand. The distribution in the flow direction of iodine indicated that the ease of desorption depends upon the situation of adsorption. Easily desorbed case was named Henry type adsorption. Hardly desorbed case was named absorption type. Discussion is made on experimental results. (Fukutomi, T.)

  5. The development and genesis of a small thaw lake filling the Skaliska Basin during the Late Glacial and Holocene

    Directory of Open Access Journals (Sweden)

    Stachowicz-Rybka Renata

    2013-06-01

    Full Text Available The northern part of the Mazury Lake District is marked by the presence of a depression described as the Skaliska Basin. At the end of the Pleistocene, the Skaliska Basin was the site of functioning of a thaw lake, within series of laminated clayey sediments were formed. The surface of the clayey sediments was overlain by a sandy fan. Blocks of dead ice underlying the fan and the overlying surface of the clayey sediments were the origin of small isolated water basins. Since the Allerod they were filled with limnic sediments, passing into peats towards the upper part. In order to reconstruct the vegetational history of the Skaliska Basin and the conditions of sedimentation of the lacustrine gyttjas and peats, several sections were obtained from such basins and subjected to examination of plant macroremains, palaeolimnological analysis and AMS dating. Sedimentation of lacustrine sediments began with sands with an admixture of silt and peat. The beginning of sedimentation of lacustrine sands of aeolian origin falls within the Allerod, whereas the end of that process in ca the middle of the Preboreal. Sands are frequently overlain by a strongly decomposed lacustrine dy sediment. Subsequently a sequence of detritus gyttja accumulated. The complex of gyttjas is interbedded with occasional Scirpo-Typheti peats. Sedimentation of lacustrine sediments is followed by accumulation of peats formed within communities with tall sedges. These communities, according to their compoition, correspond to the associations of Cicuto- Caricetum pseudocyperi Boer. et Siss. and Caricetum elatae Koch. The upper part comprises peats resembling the present-day community of Sphagnum centrale, displaying features of a transition bog. Also the occurrence of Eriophorum vaginatum confirms changes towards ombrotrophic conditions. The uppermost part of the sections often comprises heavily decomposed peat with components no longer identifiable by macroscopic analysis.

  6. Bioaugmentation of flow-through sand filters

    DEFF Research Database (Denmark)

    Samuelsen, Elin Djurhuus

    for degradation performances in flow-through sand columns, with the aim of identifying a suitable inoculant strain for future environmental applications. Another aim was to identify a suitable genetic marker to monitor phenoxy acid degradation in strain Sphingobium sp. PM2. We were not able to link motility...... and biofilm formation to the strains´ ability to adhere to sand. Nevertheless, a correlation was found between cell surface hydrophobicity and adhesion and overall degradation performances in flow-through sand columns. We identified S phingobium sp. PM2 as a promising inoculant strain, displaying efficient...... MCPA degradation for prolonged periods in flow-through sand columns. In an expression study of catabolic genes with putative roles in phenoxy acid degradation, we observed a marked upregulation of catabolic genes cadA and tfdC upon exposure to MCPA, 2,4-D, dichlorprop and mecoprop in strain PM2, which...

  7. Episodes of low dissolved oxygen indicated by ostracodes and sediment geochemistry at Crystal Lake, Illinois, USA

    Science.gov (United States)

    Curry, B. Brandon; Filippelli, G.M.

    2010-01-01

    Low dissolved oxygen during the summer and early fall controls profundal continental ostracode distribution in Crystal Lake (McHenry County), Illinois, favoring Cypria ophthalmica and Physocypria globula at water depths from 6 to 13 m. These species also thrived in the lake's profundal zone from 14,165 to 9600 calendar year before present (cal yr b.p.) during the late Boiling, Allerod, and Younger Dryas chronozones, and early Holocene. Characterized by sand, cemented tubules, large aquatic gastropod shells, and littoral ostracode valves, thin (1-6 cm) tempestite deposits punctuate thicker deposits of organic gyttja from 16,080 to 11,900 cal yr b.p. The succeeding 2300 yr (11,900-9600 cal yr b.p.) lack tempestites, and reconstructed water depths were at their maximum. Deposition of marl under relatively well-oxygenated conditions occurred during the remainder of the Holocene until the arrival of Europeans, when the lake returned to a pattern of seasonally low dissolved oxygen. Such conditions are also indicated in the lake sediment by the speciation of phosphorus, high concentrations of organic carbon, and abundant iron and manganese occluded to mineral grains. Initial low dissolved oxygen was probably caused by the delivery of dissolved P and Fe in shallow groundwater, the chemistry of which was influenced by Spodosol pedogenesis under a spruce forest. The triggering may have been regionally warm and wet conditions associated with retreat of the Lake Michigan lobe (south-central Laurentide Ice Sheet). ?? 2010, by the American Society of Limnology and Oceanography Inc.

  8. Hydrology and water quality of East Lake Tohopekaliga, Osceola County, Florida

    Science.gov (United States)

    Schiffer, Donna M.

    1987-01-01

    East Lake Tohopekaliga, one of the major lakes in central Florida, is located in the upper Kissimmee River basin in north-east Osceola County. It is one of numerous lakes in the upper basin used for flood control, in addition to recreation and some irrigation of surrounding pasture. This report is the fourth in a series of lake reconnaissance studies in the Kissimmee River basin prepared in cooperation with the South Florida Water Management District. The purpose of the report is to provide government agencies and the public with a brief summary of the lake 's hydrology and water quality. Site information is given and includes map number, site name, location, and type of data available (specific conductivity, pH, alkalinity, turbidity, color, dissolved oxygen, hardness, dissolved chlorides, dissolved sodium, dissolved calcium, dissolved magnesium, dissolved potassium, nitrogen, ammonia, nitrates, carbon and phosphorus). The U.S. Geological Survey (USGS) maintained a lake stage gaging station on East Lake Tohopekaliga from 1942 to 1968. The South Florida Water Management District has recorded lake stage since 1963. Periodic water quality samples have been collected from the lake by the South Florida Water Management District and USGS. Water quality and discharge data have been collected for one major tributary to the lake, Boggy Creek. Although few groundwater data are available for the study area, results of previous studies of the groundwater resources of Osceola County are included in this report. To supplement the water quality data for East Lake Tohopekaliga, water samples were collected at selected sites in November 1982 (dry season) and in August 1983 (rainy season). Samples were taken at inflow points, and in the lake, and vertical profiles of dissolved oxygen and temperature were measured in the lake. A water budget from an EPA report on the lake is also included. (Lantz-PTT)

  9. Leishmania infantum nicotinamidase is required for late-stage development in its natural sand fly vector, Phlebotomus perniciosus.

    Science.gov (United States)

    Gazanion, Elodie; Seblova, Veronika; Votypka, Jan; Vergnes, Baptiste; Garcia, Déborah; Volf, Petr; Sereno, Denis

    2012-04-01

    Leishmania infantum nicotinamidase, encoded by the Lipnc1 gene, converts nicotinamide into nicotinicacid to ensure Nicotinamide–Adenine–Dinucleotide (NAD+) biosynthesis. We were curious to explore the role of this enzyme during L. infantum development in its natural sand fly vector, Phlebotomus perniciosus (Diptera, Phlebotominae), using null mutants with a deleted Lipnc1 gene. The null mutants developed as well as the wild type L. infantum at the early time points post their ingestion within the bloodmeal. In contrast, once the blood meal digestion was completed, the null mutants were unable to develop further and establish late-stage infections. Data highlight the importance of the nicotinamide degradation pathway for Leishmania development in sand flies. They indicate that the endogenous nicotinamidase is essential for Leishmania development in the sand fly after the blood meal has been digested and the remnants defecated.

  10. A Viable Microbial Community in a Subglacial Volcanic Crater Lake, Iceland

    Science.gov (United States)

    Gaidos, Eric; Lanoil, Brian; Thorsteinsson, Thorsteinn; Graham, Andrew; Skidmore, Mark; Han, Suk-Kyun; Rust, Terri; Popp, Brian

    2004-09-01

    We describe a viable microbial community in a subglacial lake within the Grímsvötn volcanic caldera, Iceland. We used a hot water drill to penetrate the 300-m ice shelf and retrieved lake water and volcanic tephra sediments. We also acquired samples of borehole water before and after penetration to the lake, overlying glacial ice and snow, and water from a nearby subaerial geothermal lake for comparative analyses. Lake water is at the freezing point and fresh (total dissolved solids = 260 mg L-1). Detectable numbers of cells were found in samples of the lake water column and tephra sediments: 2 × 104 ml-1 and 4 × 107 g-1, respectively. Plate counts document abundant cold-adapted cultivable organisms in the lake water, but not in the borehole (before penetration) or glacial ice. Denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments amplified from genomic DNA extracted from Gr??msv??tn samples indicates that the lake community is distinct from the assemblages of organisms in borehole water (before penetration) and the overlying ice and snow. Sequencing of selected DGGE bands revealed that many sequences are highly similar to known psychrophilic organisms or cloned DNA from other cold environments. Significant uptake of 14C-labeled bicarbonate occurred in dark, low-temperature incubations of lake water samples, indicating the presence of autotrophs. Acetylene reduction assays under similar incubation conditions showed no significant nitrogen fixation potential by lake water samples. This may be a consequence of the inhibition of diazotrophy by nitrogen in the lake.

  11. Meeting the challenge - solutions for managing oil sands tailings: report of the fine tailings fundamentals consortium 1989-1995

    International Nuclear Information System (INIS)

    1996-01-01

    The development and demonstration of effective alternatives for the management of fine tailings in the oil sands industry were discussed in a report describing the work of the Fine Tailings Fundamentals Consortium during the period from 1989 to 1995. The final report of the Consortium is a four-volume publication entitled 'Advances in Oil Sands Tailings Research' which is the state-of-the-art reference to key issues in the reclamation of fine tailings. Government regulations now make it the responsibility of industry to integrate the fine tailings into reclaimed landscapes, so that the final landscape is equal in productive capability to the pre-disturbed state. Impressive progress has been made in understanding the formation of fine tailings and in characterizing their properties, much of it through the work of this Consortium. Fundamental research on the clay particles within fine tailings provides a better understanding of how to manage them. Although there is no 'magic bullet', research has demonstrated that an integrated approach incorporating fine tailings with a variety of elements, uplands, lakes and wetlands, offer the best hope for an environmentally sound solution. figs

  12. Booming Sand Dunes

    Science.gov (United States)

    Vriend, Nathalie

    "Booming" sand dunes are able to produce low-frequency sound that resembles a pure note from a music instrument. The sound has a dominant audible frequency (70-105 Hz) and several higher harmonics and may be heard from far distances away. A natural or induced avalanche from a slip face of the booming dune triggers the emission that may last for several minutes. There are various references in travel literature to the phenomenon, but to date no scientific explanation covered all field observations. This thesis introduces a new physical model that describes the phenomenon of booming dunes. The waveguide model explains the selection of the booming frequency and the amplification of the sound in terms of constructive interference in a confined geometry. The frequency of the booming is a direct function of the dimensions and velocities in the waveguide. The higher harmonics are related to the higher modes of propagation in the waveguide. The experimental validation includes quantitative field research at the booming dunes of the Mojave Desert and Death Valley National Park. Microphone and geophone recordings of the acoustic and seismic emission show a variation of booming frequency in space and time. The analysis of the sensor data quantifies wave propagation characteristics such as speed, dispersion, and nonlinear effects and allows the distinction between the source mechanism of the booming and the booming itself. The migration of sand dunes results from a complicated interplay between dune building, wind regime, and precipitation. The morphological and morphodynamical characteristics of two field locations are analyzed with various geophysical techniques. Ground-penetrating radar images the subsurface structure of the dunes and reveal a natural, internal layering that is directly related to the history of dune migration. The seismic velocity increases abruptly with depth and gradually increases with downhill position due to compaction. Sand sampling shows local

  13. Oil sands economic impacts Canada : CERI report : backgrounder

    International Nuclear Information System (INIS)

    2005-09-01

    Oil sands production now accounts for 1 out of every 2 barrels of supply in Western Canada. It is anticipated that Alberta's oil sands sector will experience significant growth over the next few decades. This paper provided an outline of the challenges and economic impacts resulting from oil sands development in Canada. Alberta's oil sands reserves are estimated at 175 billion barrels that are deemed economically recoverable using current technology. At current production levels, reserves will sustain production of 2.5 million barrels per day for the next 200 years. A study by the Canadian Energy Research Institute (CERI) has forecast $100 billion in investment for the 2000-2020 period. Numerous companies hold leases and are planning new projects. A number of recent advances in oil sands technology are expected to further reduce costs as development matures. A royalty and tax regime that provides long-term fiscal certainty is a key factor that supports current oil sands growth forecasts. The CERI study has indicated that economic spinoffs from oil sands development relate to employment generated outside of Alberta, and that the largest percentage of government revenue accrues to the federal government. However, development may be constrained because the pace of growth in the sector may exceed underlying infrastructure related to roads, housing and municipal services. An adequate workforce of qualified trades and technical and professional people is also crucial. Several pipeline projects have been proposed to deliver oil sands crudes to new markets over the next decade. It was concluded that the billions of dollars invested in oil sands in Alberta will contribute to the economic prosperity of the entire country. 11 figs

  14. Effect of substrate size on sympatric sand darter benthic habitat preferences

    Science.gov (United States)

    Thompson, Patricia A.; Welsh, Stuart A.; Rizzo, Austin A.; Smith, Dustin M.

    2017-01-01

    The western sand darter, Ammocrypta clara, and the eastern sand darter, A. pellucida, are sand-dwelling fishes that have undergone range-wide population declines, presumably owing to habitat loss. Habitat use studies have been conducted for the eastern sand darter, but literature on the western sand darter remains sparse. To evaluate substrate selection and preference, western and eastern sand darters were collected from the Elk River, West Virginia, one of the few remaining rivers where both species occur sympatrically. In the laboratory, individuals were given the choice to bury into five equally available and randomly positioned substrates ranging from fine sand to granule gravel (0.12–4.0 mm). The western sand darter selected for coarse and medium sand, while the eastern sand darter was more of a generalist selecting for fine, medium, and coarse sand. Substrate selection was significantly different (p = 0.02) between species in the same environment, where the western sand darter preferred coarser substrate more often compared to the eastern sand darter. Habitat degradation is often a limiting factor for many species of rare freshwater fish, and results from this study suggest that western and eastern sand darters may respond differently to variations in benthic substrate composition.

  15. Subsurface imaging reveals a confined aquifer beneath an ice-sealed Antarctic lake

    DEFF Research Database (Denmark)

    Dugan, H. A.; Doran, P. T.; Tulaczyk, S.

    2015-01-01

    Liquid water oases are rare under extreme cold desert conditions found in the Antarctic McMurdo Dry Valleys. Here we report geophysical results that indicate that Lake Vida, one of the largest lakes in the region, is nearly frozen and underlain by widespread cryoconcentrated brine. A ground...... this zone to be a confined aquifer situated in sediments with a porosity of 23-42%. Discovery of this aquifer suggests that subsurface liquid water may be more pervasive in regions of continuous permafrost than previously thought and may represent an extensive habitat for microbial populations. Key Points...... Geophysical survey finds low resistivities beneath a lake in Antarctic Dry Valleys Liquid brine abundant beneath Antarctic lake Aquifer provides microbial refugium in cold desert environment...

  16. Energy density of lake whitefish Coregonus clupeaformis in Lakes Huron and Michigan

    Science.gov (United States)

    Pothoven, S.A.; Nalepa, T.F.; Madenjian, C.P.; Rediske, R.R.; Schneeberger, P.J.; He, J.X.

    2006-01-01

    We collected lake whitefish Coregonus clupeaformis off Alpena and Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA in Lake Michigan during 2002–2004. We determined energy density and percent dry weight for lake whitefish from both lakes and lipid content for Lake Michigan fish. Energy density increased with increasing fish weight up to 800 g, and then remained relatively constant with further increases in fish weight. Energy density, adjusted for weight, was lower in Lake Huron than in Lake Michigan for both small (≤800 g) and large fish (>800 g). Energy density did not differ seasonally for small or large lake whitefish or between adult male and female fish. Energy density was strongly correlated with percent dry weight and percent lipid content. Based on data from commercially caught lake whitefish, body condition was lower in Lake Huron than Lake Michigan during 1981–2003, indicating that the dissimilarity in body condition between the lakes could be long standing. Energy density and lipid content in 2002–2004 in Lake Michigan were lower than data for comparable sized fish collected in 1969–1971. Differences in energy density between lakes were attributed to variation in diet and prey energy content as well as factors that affect feeding rates such as lake whitefish density and prey abundance.

  17. The Geodiversity in Drift Sand Landscapes of The Netherlands

    Science.gov (United States)

    van den Ancker, Hanneke; Jungerius, Pieter Dirk; Riksen, Michel

    2015-04-01

    The authors carried out detailed field studies of more than twelve drift sand landscapes in The Netherlands. The objective of these studies was to restore Natura-2000 values by restoring the wind activity. Active drift sands occur almost exclusively in The Netherlands, Natura 2000 habitat 2330 'Inland dunes with open Corynephorus and Agrostis grasslands', for which reason our country is largely responsible for this European landscape. Active drift sands had almost disappeared for two reasons: first, the stabilization of the drift sands by air pollution, mainly nitrogen, which stimulates the growth of algae and grasses that initiate soil formation, and second, by the growth of forests surrounding the sands, which decreases the wind force. The restoration studies revealed differences in the geodiversity between and within the drift sand areas. Whereas the drift sands on geological and soil maps show as almost homogenous areas, they have in fact highly variable geo-conditions of which examples will be given. These geodiversity aspects concern differences in geomorphological structure, origin, sediments and age of the drift sands. Differences in wind and water erosion, trampling and soil formation add to the geodiversity within the drift sand areas. Especially in the primary stages of succession the differences in geodiversity are relevant for the Natura-2000 values. We discerned three main types of active sands. Firstly, the impressive drift sands with large parabolic dune structures, often consisting of series of interlocking parabolic dunes. They developed from the northeast towards the southwest, against the direction of the dominant wind, and must have taken centuries to develop. Small parts of these systems are still active, other parts show different degrees of soil formation. Their origin is still unclear but probably dates from medieval times (Heidinga, 1985, Jungerius & Riksen, 2008). Second are the drift sand areas with irregular hills from 0.5 to about 2

  18. Effects of lake trout refuges on lake whitefish and cisco in the Apostle Islands Region of Lake Superior

    Science.gov (United States)

    Zuccarino-Crowe , Chiara M.; Taylor, William W.; Hansen, Michael J.; Seider, Michael J.; Krueger, Charles C.

    2016-01-01

    Lake trout refuges in the Apostle Islands region of Lake Superior are analogous to the concept of marine protected areas. These refuges, established specifically for lake trout (Salvelinus namaycush) and closed to most forms of recreational and commercial fishing, were implicated as one of several management actions leading to successful rehabilitation of Lake Superior lake trout. To investigate the potential significance of Gull Island Shoal and Devils Island Shoal refuges for populations of not only lake trout but also other fish species, relative abundances of lake trout, lake whitefish (Coregonus clupeaformis), and cisco (Coregonus artedi) were compared between areas sampled inside versus outside of refuge boundaries. During 1982–2010, lake trout relative abundance was higher and increased faster inside the refuges, where lake trout fishing was prohibited, than outside the refuges. Over the same period, lake whitefish relative abundance increased faster inside than outside the refuges. Both evaluations provided clear evidence that refuges protected these species. In contrast, trends in relative abundance of cisco, a prey item of lake trout, did not differ significantly between areas inside and outside the refuges. This result did not suggest indirect or cascading refuge effects due to changes in predator levels. Overall, this study highlights the potential of species-specific refuges to benefit other fish species beyond those that were the refuges' original target. Improved understanding of refuge effects on multiple species of Great Lakes fishes can be valuable for developing rationales for refuge establishment and predicting associated fish community-level effects.

  19. Stable isotopes, δ18O and δ2H, in the study of water balance of Lake Massoko, Tanzania: Investigation of the exchange between lake and underground water

    International Nuclear Information System (INIS)

    Bergonzini, L.; Gibert, E.; Winckel, A.

    2002-01-01

    Full text: The stable oxygen and deuterium isotope compositions of a lake depend upon its water balance. Therefore the balance equations of stable isotopes, which imply calculation of the composition of evaporating moisture α E , provide information for assessing the water balance. In most cases, this approach is used to investigate the relationships between lakes and groundwater. Lake Massoko (8 deg. 20'S, 33 deg. 45'E, 870 m.a.s.l.) is a freshwater maar-lake without surface outlet. The lake surface and its runoff area cover 0.38 and 0.55 km 2 respectively. In contrast with the mean annual rainfall in the other parts of south Tanzania (1000-1200 mm y -1 ), the presence of Lake Malawi to the South, and the high ranges to the North (Mounts Poroto, Rungwe and Livingstone) imply local climatic features. Air masses overloaded with humidity bypassing Lake Malawi are submitted, especially in April, to ascending currents, producing rainfalls up to 2450 mm y -1 over Massoko area. Because of the evaporation rate from the lake's surface (around 2100 mm y -1 ) and without taking into account the runoff from the drainage basin, hydrological balance is positive and imply underground lost. One of most difficult points in the establishment of the isotope balances is the calculation of the composition of the evaporated water (δ E ), which requires an estimation of the isotopic composition of the water vapour in the atmosphere over the lake (δ Atm ). Without direct measurements, two ways can be used for the determination of the vapour composition (i) equilibrium with precipitation and reconstitution from them, or (ii) calculation from the balances of a terminal lake of the region. Both approaches are presented and compared, but only the second one allows physical solutions. δ Atm determined from Lake Rukwa hydrological and isotope balances has been used to calculate values for δ E over Lake Massoko. The estimation of δ Atm obtained from Lake Rukwa budgets presents a deuterium

  20. Experimental investigation of sanding propensity for the Andrew completion

    Energy Technology Data Exchange (ETDEWEB)

    Venkitaraman, A.; Li, H. [Schlumberger Perforating and Testing Center (United Kingdom); Leonard, A. J.; Bowden, P. R. [BP Exploration (United Kingdom)

    1998-12-31

    A series of laboratory experiments were performed on three reservoir core samples selected from two plot wells to confirm the likelihood of sand production during the completion phase of the planned Andrew horizontal wells, and to perform risk analysis of formation failure at the time of underbalance perforation, and expected producing conditions. CT scans revealed no perforation failure, and the core samples did not show any propensity to produce sand during single-phase oil flow. Transient sand production was observed when water cut was introduced, but sand production declined as the percentage of water cut was increased. There was no evidence of sand production in the core samples during depletion testing either, and the wells were subsequently completed with perforated cemented liners without sand control. No sand problems have been encountered in two years of production, with some wells in water cut and declined reservoir pressure of 200 psi. 8 refs., 3 tabs., 5 figs.

  1. Evaluation of wettability of binders used in moulding sands

    Directory of Open Access Journals (Sweden)

    Hutera B.

    2007-01-01

    Full Text Available Binders used in moulding sand have the differential properties. One of the main parameters influencing on moulding sand properties is wettability of the sand grain by binding material. In the article some problems concerned with wettability evaluation have been presented and the importance of this parameter for quantity description of process occurring in system: binder- sand grain has been mentioned. The procedure of wetting angle measurement and operation of prototype apparatus for wettability investigation of different binders used in moulding sand have been described, as well as the results of wetting angle measurement for different binders at different conditions. The addition of little amount of proper diluent to binder results in the state of equilibrium reached almost immediately. Such addition can also reduce the value of equilibrium contact angle. The uniform distribution of binder on the surface of the sand grains and reducing of the required mixing time can be obtained. It has also a positive effect on the moulding sand strength.

  2. Lake Representations in Global Climate Models: An End-User Perspective

    Science.gov (United States)

    Rood, R. B.; Briley, L.; Steiner, A.; Wells, K.

    2017-12-01

    The weather and climate in the Great Lakes region of the United States and Canada are strongly influenced by the lakes. Within global climate models, lakes are incorporated in many ways. If one is interested in quantitative climate information for the Great Lakes, then it is a first principle requirement that end-users of climate model simulation data, whether scientists or practitioners, need to know if and how lakes are incorporated into models. We pose the basic question, how are lakes represented in CMIP models? Despite significant efforts by the climate community to document and publish basic information about climate models, it is unclear how to answer the question about lake representations? With significant knowledge of the practice of the field, then a reasonable starting point is to use the ES-DOC Comparator (https://compare.es-doc.org/ ). Once at this interface to model information, the end-user is faced with the need for more knowledge about the practice and culture of the discipline. For example, lakes are often categorized as a type of land, a counterintuitive concept. In some models, though, lakes are specified in ocean models. There is little evidence and little confidence that the information obtained through this process is complete or accurate. In fact, it is verifiably not accurate. This experience, then, motivates identifying and finding either human experts or technical documentation for each model. The conclusion from this exercise is that it can take months or longer to provide a defensible answer to if and how lakes are represented in climate models. Our experience with lake finding is that this is not a unique experience. This talk documents our experience and explores barriers we have identified and strategies for reducing those barriers.

  3. Nuclear energy in the oils sands

    International Nuclear Information System (INIS)

    Arsenault, J.E.

    2014-01-01

    The major Canadian oil sands are located in Alberta and Saskatchewan, with most production from the strata along the Athabasca River in Alberta. The economically recoverable oil sands reserves are estimated to be 168 billion barrels which at a current production rate of 1.8 million barrels per day (2012), are projected to last a very long time. Canada has been blessed with vast energy resources which make it potentially energy-independent and able to provide significant exports but there are concerns that their development cannot be managed in a wholly acceptable manner. Comparable concerns have been applied to nuclear energy in the past and in recent times to the oil sands. The technologies associated with these energy sources have always been controversial because they are at the confluence of economics and politics where finding a balance between risk and reward is difficult. So it should be no surprise that when these technologies get linked together in certain proposals their prospect for success is doubly difficult. The possible use of nuclear energy for production of oil from the oil sands dates back to the late 1950s, when an experiment to mine the oil by detonating an underground nuclear device was proposed. It was predicted that the heat and pressure released from such a device would create a large cavern into which oil would flow, and from where it would be pumped to the surface. Almost at the same time, oil sands research using conventional sources of energy had culminated with the development of practical refining processes, essentially those still in use today. These methods require large amounts of heat energy in the form of hot water and steam. In this century nuclear energy was proposed as the source for the heat required by the oil sands production processes. To date neither of these nuclear proposals for oil sands projects have been successful, because the economic and political balance could not be struck. (author)

  4. The provenance of Taklamakan desert sand

    Science.gov (United States)

    Rittner, Martin; Vermeesch, Pieter; Carter, Andrew; Bird, Anna; Stevens, Thomas; Garzanti, Eduardo; Andò, Sergio; Vezzoli, Giovanni; Dutt, Ripul; Xu, Zhiwei; Lu, Huayu

    2016-03-01

    Sand migration in the vast Taklamakan desert within the Tarim Basin (Xinjiang Uyghur Autonomous region, PR China) is governed by two competing transport agents: wind and water, which work in diametrically opposed directions. Net aeolian transport is from northeast to south, while fluvial transport occurs from the south to the north and then west to east at the northern rim, due to a gradual northward slope of the underlying topography. We here present the first comprehensive provenance study of Taklamakan desert sand with the aim to characterise the interplay of these two transport mechanisms and their roles in the formation of the sand sea, and to consider the potential of the Tarim Basin as a contributing source to the Chinese Loess Plateau (CLP). Our dataset comprises 39 aeolian and fluvial samples, which were characterised by detrital-zircon U-Pb geochronology, heavy-mineral, and bulk-petrography analyses. Although the inter-sample differences of all three datasets are subtle, a multivariate statistical analysis using multidimensional scaling (MDS) clearly shows that Tarim desert sand is most similar in composition to rivers draining the Kunlun Shan (south) and the Pamirs (west), and is distinctly different from sediment sources in the Tian Shan (north). A small set of samples from the Junggar Basin (north of the Tian Shan) yields different detrital compositions and age spectra than anywhere in the Tarim Basin, indicating that aeolian sediment exchange between the two basins is minimal. Although river transport dominates delivery of sand into the Tarim Basin, wind remobilises and reworks the sediment in the central sand sea. Characteristic signatures of main rivers can be traced from entrance into the basin to the terminus of the Tarim River, and those crossing the desert from the south to north can seasonally bypass sediment through the sand sea. Smaller ephemeral rivers from the Kunlun Shan end in the desert and discharge their sediment there. Both river run

  5. Nuclear energy in the oils sands

    Energy Technology Data Exchange (ETDEWEB)

    Arsenault, J.E.

    2014-09-15

    The major Canadian oil sands are located in Alberta and Saskatchewan, with most production from the strata along the Athabasca River in Alberta. The economically recoverable oil sands reserves are estimated to be 168 billion barrels which at a current production rate of 1.8 million barrels per day (2012), are projected to last a very long time. Canada has been blessed with vast energy resources which make it potentially energy-independent and able to provide significant exports but there are concerns that their development cannot be managed in a wholly acceptable manner. Comparable concerns have been applied to nuclear energy in the past and in recent times to the oil sands. The technologies associated with these energy sources have always been controversial because they are at the confluence of economics and politics where finding a balance between risk and reward is difficult. So it should be no surprise that when these technologies get linked together in certain proposals their prospect for success is doubly difficult. The possible use of nuclear energy for production of oil from the oil sands dates back to the late 1950s, when an experiment to mine the oil by detonating an underground nuclear device was proposed. It was predicted that the heat and pressure released from such a device would create a large cavern into which oil would flow, and from where it would be pumped to the surface. Almost at the same time, oil sands research using conventional sources of energy had culminated with the development of practical refining processes, essentially those still in use today. These methods require large amounts of heat energy in the form of hot water and steam. In this century nuclear energy was proposed as the source for the heat required by the oil sands production processes. To date neither of these nuclear proposals for oil sands projects have been successful, because the economic and political balance could not be struck. (author)

  6. Stereotactic Target point Verification in Actual Treatment Position of Radiosurgery

    International Nuclear Information System (INIS)

    Yun, Hyong Geun; Lee, Hyun Koo

    1995-01-01

    Purpose : Authors tried to enhance the safety and accuracy of radiosurgery by verifying stereotactic target point in actual treatment position prior to irradiation. Materials and Methods : Before the actual treatment, several sections of anthropomorphic head phantom were used to create a condition of unknown coordinated of the target point. A film was sand witched between the phantom sections and punctured by sharp needle tip. The tip of the needle represented the target point. The head phantom was fixed to the stereotactic ring and CT scan was done with CT localizer attached to the ring. After the CT scanning, the stereotactic coordinates of the target point were determined. The head phantom was secured to accelerator's treatment couch and the movement of laser isocenter to the stereotactic coordinates determined by CT scanning was performed using target positioner. Accelerator's anteroposterior and lateral portal films were taken using angiographic localizers. The stereotactic coordinates determined by analysis of portal films were compared with the stereotactic coordinates previously determined by CT scanning. Following the correction of discrepancy, the head phantom was irradiated using a stereotactic technique of several arcs. After the irradiation, the film which was sand witched between the phantom sections was developed and the degree of coincidence between the center of the radiation distribution with the target point represented by the hole in the film was measured. In the treatment of actual patients, the way of determining the stereotactic coordinates with CT localizers and angiographic localizers between two sets of coordinates, we proceeded to the irradiation of the actual patient. Results : In the phantom study, the agreement between the center of the radiation distribution and the localized target point was very good. By measuring optical density profiles of the sand witched film along axes that intersected the target point, authors could confirm

  7. Hazards of volcanic lakes: analysis of Lakes Quilotoa and Cuicocha, Ecuador

    Directory of Open Access Journals (Sweden)

    G. Gunkel

    2008-01-01

    Full Text Available Volcanic lakes within calderas should be viewed as high-risk systems, and an intensive lake monitoring must be carried out to evaluate the hazard of potential limnic or phreatic-magmatic eruptions. In Ecuador, two caldera lakesLakes Quilotoa and Cuicocha, located in the high Andean region >3000 a.s.l. – have been the focus of these investigations. Both volcanoes are geologically young or historically active, and have formed large and deep calderas with lakes of 2 to 3 km in diameter, and 248 and 148 m in depth, respectively. In both lakes, visible gas emissions of CO2 occur, and an accumulation of CO2 in the deep water body must be taken into account.

    Investigations were carried out to evaluate the hazards of these volcanic lakes, and in Lake Cuicocha intensive monitoring was carried out for the evaluation of possible renewed volcanic activities. At Lake Quilotoa, a limnic eruption and diffuse CO2 degassing at the lake surface are to be expected, while at Lake Cuicocha, an increased risk of a phreatic-magmatic eruption exists.

  8. Changes in active eolian sand at northern Coachella Valley, California

    Science.gov (United States)

    Katra, Itzhak; Scheidt, Stephen; Lancaster, Nicholas

    2009-04-01

    Climate variability and rapid urbanization have influenced the sand environments in the northern Coachella Valley throughout the late 20th century. This paper addresses changes in the spatial relationships among different sand deposits at northern Coachella Valley between two recent time periods by using satellite data acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The approach employed here, involving multispectral thermal infrared (TIR) data and spectral mixture analysis, has shown that the major sand deposits can be spatially modeled at northern Coachella Valley. The "coarse-grained (quartz-rich) sand" deposit is associated with active eolian sand, and the "mixed sandy soil" and "fine-grained (quartz-rich) sand" deposits are associated with inactive eolian sand. The fractional abundance images showed a significant decrease between 2000 and 2006 in the percentage of active sand in the major depositional area for fluvial sediment, the Whitewater River, but also in two downwind areas: the Whitewater and Willow Hole Reserves. The pattern of the active sand appears to be related to variations in annual precipitation (wet and dry years) and river discharge in the northern Coachella Valley. We suggest here that recent human modifications to the major watercourses that supply sand affect the capability of fluvial deposition areas to restore sediments over time and consequently the responses of the sand transport system to climate change, becoming more sensitive to dry years where areas of active sand may shrink, degrade, and/or stabilize faster. The approach utilized in this study can be advantageous for future monitoring of sand in the northern Coachella Valley for management of these and similar environments.

  9. Namibia : triaxial test on sand

    DEFF Research Database (Denmark)

    Steenfelt, Jørgen S.; Jacobsen, Kim P.

    In connection with a harbour project the friction angle of a fine sand is required. On Friday 13 March 1998 the Danish Geotechnical Institute (DGI) delivered app. 2.5 kg sand for testing at the Geotechnical Engineering Laboratory, Aalborg University. The present Data Report summarises the results...... of two CID, isotropically consolidated, drained triaxial tests carried out according to the instructions in DG1 letter dated 13 March 1998....

  10. An experimental study on the resistance and movement of short pile installed in sands under horizontal pullout load

    Directory of Open Access Journals (Sweden)

    Oh Kyun Kwon

    2014-03-01

    Full Text Available In this study, the model tests were conducted on the short piles installed in sands under a horizontal pullout load to investigate their behavior characteristics. From the horizontal loading tests where dimensions of the pile diameter and length, and loading point were varied, the horizontal pullout resistance and the rotational and translational movement pattern of the pile were investigated. As a result, the horizontal pullout resistance of the pile embedded in sands was dependent on the pile length, diameter, loading point, etc. The ultimate horizontal pullout load tended to increase as the loading point (h/L moved to the bottom from the top of the pile, regardless of the ratio between the pile length and diameter (L/D, reached the maximum value at the point of h/L = 0.75, and decreased afterwards. When the horizontal pullout load acted on the upper part above the middle of the pile, the pile rotated clockwise and moved to the pullout direction, and the pivot point of the pile was located at 150–360mm depth below the ground surface. On the other hand, when the horizontal pullout load acted on the lower part of the pile, the pile rotated counterclockwise and travelled horizontally, and the rotational angle was very small.

  11. Pattern formation - Instabilities in sand ripples

    DEFF Research Database (Denmark)

    Hansen, J. L.; v. Hecke, M.; Haaning, A.

    2001-01-01

    Sand ripples are seen below shallow wavy water and are formed whenever water oscillates over a bed of sand. Here we analyse the instabilities that can upset this perfect patterning when the ripples are subjected to large changes in driving amplitude or frequency, causing them to deform both...

  12. Southeast Florida Sediment Assessment and Needs Determination (SAND) Study

    Science.gov (United States)

    2014-09-01

    sand with some shell beds, sandstone , and limestone *Miami Limestone 0 to 80 ft Oolitic limestone, quartz sand, and sandstone Anastasia 0 to 100 ft...Sand, shell beds, marl, calcareous sandstone (coquina/calcarenite) Fort Thompson 0 to 80 ft Silty limestone, silty sand, clayey marl, shell marl...highly- to moderately- weathered quartzose sandstone , and highly-weathered (saprolitic) to moderately-weathered hard limestone. North-south and

  13. Magnetic and gravity studies of Mono Lake, east-central, California

    Science.gov (United States)

    Athens, Noah D.; Ponce, David A.; Jayko, Angela S.; Miller, Matt; McEvoy, Bobby; Marcaida, Mae; Mangan, Margaret T.; Wilkinson, Stuart K.; McClain, James S.; Chuchel, Bruce A.; Denton, Kevin M.

    2014-01-01

    From August 26 to September 5, 2011, the U.S. Geological Survey (USGS) collected more than 600 line-kilometers of shipborne magnetic data on Mono Lake, 20 line-kilometers of ground magnetic data on Paoha Island, 50 gravity stations on Paoha and Negit Islands, and 28 rock samples on Paoha and Negit Islands, in east-central California. Magnetic and gravity investigations were undertaken in Mono Lake to study regional crustal structures and to aid in understanding the geologic framework, in particular regarding potential geothermal resources and volcanic hazards throughout Mono Basin. Furthermore, shipborne magnetic data illuminate local structures in the upper crust beneath Mono Lake where geologic exposure is absent. Magnetic and gravity methods, which sense contrasting physical properties of the subsurface, are ideal for studying Mono Lake. Exposed rock units surrounding Mono Lake consist mainly of Quaternary alluvium, lacustrine sediment, aeolian deposits, basalt, and Paleozoic granitic and metasedimentary rocks (Bailey, 1989). At Black Point, on the northwest shore of Mono Lake, there is a mafic cinder cone that was produced by a subaqueous eruption around 13.3 ka. Within Mono Lake there are several small dacite cinder cones and flows, forming Negit Island and part of Paoha Island, which also host deposits of Quaternary lacustrine sediments. The typical density and magnetic properties of young volcanic rocks contrast with those of the lacustrine sediment, enabling us to map their subsurface extent.

  14. Modelling the behavior of an oil saturated sand

    International Nuclear Information System (INIS)

    Evgin, E.; Altaee, A.; Lord, S.; Konuk, I.

    1990-01-01

    The experiments carried out in an earlier study show the oil contamination affects the strength and deformation characteristics of a crushed quartz sand. In the present study, a mathematical soil model is used to simulate the mechanical behavior of the same sand. The model parameters are determined for both clean and oil contaminated soil. Simulations are made for the stress-strain behavior of the soil in drained and undrained conventional traixial compression tests. In order to illustrate the effect of changes in the soil properties on the behavior of an engineering structure, a finite element analysis is carried out. In this paper comparative results are presented to show the differences in the behavior of a foundation resting on a clean sand, on an oil contaminated sand, and on a sand contaminated locally

  15. Oblique second-order sand transport pathways on an intertidal sand flat in a natural tidal inlet system

    DEFF Research Database (Denmark)

    Ernstsen, Verner Brandbyge; Lefebvre, Alice; Kroon, Aart

    2013-01-01

    tide, sand is transported along ESE-oriented pathways across the intertidal flat towards the inner tidal basin. During the late stages of ebb tide, sand is transported in drainage channels (WSWoriented) from the intertidal flat towards the inlet channel. During storm events with winds from SW, wave...

  16. Oil sands supply outlook

    International Nuclear Information System (INIS)

    Dunbar, R.

    2004-01-01

    In March 2004, The Canadian Energy Research Institute released a report on the expected future supply from Alberta's oil sands. The report indicates that the future for the already well-established oil sands industry is promising, particularly given the outlook for oil prices. The challenges facing the industry include higher industry supply costs and the need for innovative commercial and technological solutions to address the risks of irregularities and changes in crude oil prices. In 2003, the industry produced 874 thousand barrels per day of synthetic crude oil and unprocessed crude bitumen. This represents 35 per cent of Canada's total oil production. Current production capacity has increased to 1.0 million barrels per day (mbpd) due to new projects. This number may increase to 3.5 mbpd by 2017. Some new projects may be deferred due to the higher raw bitumen and synthetic crude oil supply costs. This presentation provided supply costs for a range of oil sands recovery technologies and production projections under various business scenarios. tabs., figs

  17. Gasification of oil sand coke: review

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E. [IMAF Group, Ottawa, ON (Canada)

    1998-08-01

    The production of synthetic crude from the tar sands in Western Canada has been steadily increasing. Most of the delayed coke produced by Suncor is combusted on site, whereas all fluid coke produced by Syncrude is stockpiled.The database on the chemical and physical properties of the oil sand coke, including the composition and fusion properties of the mineral matter, has been established. The reactivity of the coke was determined by oxygen chemisorption, fixed bed and fluid bed bench scale gasification and pilot plant gasification. The reactivity of the oil sand coke for gasification is rather low and comparable to high rank coals, such as anthracite. Slurrability tests revealed that a solid concentration in water, approaching 70 wt%, can be achieved. Gasification is the front runner among clean technologies for the conversion of carbonaceous solids to useful products. Several commercial gasifiers are available to cover the wide range of severity. Because of the low reactivity of oil sands coke, high severity conditions are required to achieve high gasification conversion. Such conditions can be attained in entrained bed gasifiers. Gasifiers employing both dry and slurry feeding systems are suitable. A high efficiency, low SO{sub x} and NO{sub x} emissions, as well as a low solid waste production are among the key advantages of the gasification technology compared with thecompeting technologies. Commercial gasification of oil sands coke is delayed because of the availability of natural gas on the site of the upgrading plants. Potential for the transportation of the oil sand coke to USA for electricity generation using the integrated gasification combined-cycle (IGCC) technology was evaluated. 27 refs., 17 figs., 9 tabs.

  18. Reuse of waste cutting sand at Lawrence Livermore National Laboratory

    International Nuclear Information System (INIS)

    Mathews, S.; Wilson, K.

    1998-01-01

    Lawrence Livermore National Laboratory (LLNL) examined the waste stream from a water jet cutting operation, to evaluate the possible reuse of waste garnet sand. The sand is a cutting agent used to shape a variety of materials, including metals. Nearly 70,000 pounds of waste sand is generated annually by the cutting operation. The Environmental Protection Department evaluated two potential reuses for the spent garnet sand: backfill in utility trenches; and as a concrete constituent. In both applications, garnet waste would replace the sand formerly purchased by LLNL for these purposes. Findings supported the reuse of waste garnet sand in concrete, but disqualified its proposed application as trench backfill. Waste sand stabilized in a concrete matrix appeared to present no metals-leaching hazard; however, unconsolidated sand in trenches could potentially leach metals in concentrations high enough to threaten ground water quality. A technical report submitted to the San Francisco Bay Regional Water Quality Control Board was reviewed and accepted by that body. Reuse of waste garnet cutting sand as a constituent in concrete poured to form walkways and patios at LLNL was approved

  19. Augmenting Sand Simulation Environments through Subdivision and Particle Refinement

    Science.gov (United States)

    Clothier, M.; Bailey, M.

    2012-12-01

    Recent advances in computer graphics and parallel processing hardware have provided disciplines with new methods to evaluate and visualize data. These advances have proven useful for earth and planetary scientists as many researchers are using this hardware to process large amounts of data for analysis. As such, this has provided opportunities for collaboration between computer graphics and the earth sciences. Through collaboration with the Oregon Space Grant and IGERT Ecosystem Informatics programs, we are investigating techniques for simulating the behavior of sand. We are also collaborating with the Jet Propulsion Laboratory's (JPL) DARTS Lab to exchange ideas and gain feedback on our research. The DARTS Lab specializes in simulation of planetary vehicles, such as the Mars rovers. Their simulations utilize a virtual "sand box" to test how a planetary vehicle responds to different environments. Our research builds upon this idea to create a sand simulation framework so that planetary environments, such as the harsh, sandy regions on Mars, are more fully realized. More specifically, we are focusing our research on the interaction between a planetary vehicle, such as a rover, and the sand beneath it, providing further insight into its performance. Unfortunately, this can be a computationally complex problem, especially if trying to represent the enormous quantities of sand particles interacting with each other. However, through the use of high-performance computing, we have developed a technique to subdivide areas of actively participating sand regions across a large landscape. Similar to a Level of Detail (LOD) technique, we only subdivide regions of a landscape where sand particles are actively participating with another object. While the sand is within this subdivision window and moves closer to the surface of the interacting object, the sand region subdivides into smaller regions until individual sand particles are left at the surface. As an example, let's say

  20. Bathymetric and sediment facies maps for China Bend and Marcus Flats, Franklin D. Roosevelt Lake, Washington, 2008 and 2009

    Science.gov (United States)

    Weakland, Rhonda J.; Fosness, Ryan L.; Williams, Marshall L.; Barton, Gary J.

    2011-01-01

    The U.S. Geological Survey (USGS) created bathymetric and sediment facies maps for portions of two reaches of Lake Roosevelt in support of an interdisciplinary study of white sturgeon (Acipenser transmontanus) and their habitat areas within Franklin D. Roosevelt Lake, Washington. In October 2008, scientists from the USGS used a boat-mounted multibeam echo sounder (MBES) to describe bathymetric data to characterize surface relief at China Bend and Marcus Flats, between Northport and Kettle Falls, Washington. In March 2009, an underwater video camera was used to view and record sediment facies that were then characterized by sediment type, grain size, and areas of sand deposition. Smelter slag has been identified as having the characteristics of sand-sized black particles; the two non-invasive surveys attempted to identify areas containing black-colored particulate matter that may be elements and minerals, organic material, or slag. The white sturgeon population in Lake Roosevelt is threatened by the failure of natural recruitment, resulting in a native population that consists primarily of aging fish and that is gradually declining as fish die and are not replaced by nonhatchery reared juvenile fish. These fish spawn and rear in the riverine and upper reservoir reaches where smelter slag is present in the sediment of the river lake bed. Effects of slag on the white sturgeon population in Lake Roosevelt are largely unknown. Two recent studies demonstrated that copper and other metals are mobilized from slag in aqueous environments with concentrations of copper and zinc in bed sediments reaching levels of 10,000 and 30,000 mg/kg due to the presence of smelter slag. Copper was found to be highly toxic to 30-day-old white sturgeon with 96-h LC50 concentrations ranging from 3 to 5 (u or mu)g copper per liter. Older juvenile and adult sturgeons commonly ingest substantial amounts of sediment while foraging. Future study efforts in Lake Roosevelt should include sampling of

  1. Depositional environment of a fan delta in a Vistulian proglacial lake (Skaliska Basin, north-eastern Poland

    Directory of Open Access Journals (Sweden)

    Woronko Barbara

    2013-06-01

    Full Text Available The study reconstructed the environment of a fan delta filling the vast end depression of the Skaliska Basin, and its overlying aeolian deposits. The formation of the large fan delta is associated with the presence of an ice-dammed lake functioning during the retreat of the Vistulian Glaciation (MIS 2. The examined material was collected from five boreholes. Sediments were analysed for their granulometric composition and subjected to analyses of frosting and rounding of quartz grains. Grain size analysis showed that the fan delta deposits are built of sand sediments of very low lateral and vertical variability. The fan delta was supplied with fluvioglacial sediments. Accumulation of sediments occurred in shallow water with a very low-gradient slope. The exposed fan delta became a site conducive to aeolian processes after the lake waters fell and the Skaliska Basin depression dried. Dune deposits overlying the fan were affected by short-distance transport so they did not acquire features typical for aeolian deposits.

  2. Automated lake-wide erosion predictions and economic damage calculations upstream of the Moses-Saunders power dam

    International Nuclear Information System (INIS)

    Zuzek, P.; Baird, W.F.; International Joint Commission, Ottawa, ON

    2008-01-01

    This presentation discussed an automated flood and erosion prediction system designed for the upstream sections of the Moses-Saunders power dam. The system included a wave prediction component along with 3-D maps, hourly run-ups, geographic information system (GIS) tools and a hazard analysis tool. Parcel, reach, township, and county databases were used to populate the system. The prediction system was used to develop detailed study sites of shore units in the study area. Shoreline classes included sand and cohesive buffs, low banks, coarse beaches, and cobble or boulder lags. Time series plots for Lake Ontario water and wave levels were presented. Great Lakes ice cover data were also included in the system as well as erosion predictions from 1961 to 1995. The system was also used to develop bluff recession equations and cumulative recession analyses for different regulation plans. Cumulative bluff recession and protection requirements were outlined. Screenshots of the flood and erosion prediction system interface were also included. tabs., figs

  3. Understanding Colombian Amazonian white sand forests

    NARCIS (Netherlands)

    Peñuela-Mora, M.C.

    2014-01-01

    Although progress has been made in studies on white sand forests in the Amazon, there is still a considerable gap in our knowledge of the unique species composition of white sand forests and their structure and dynamics, especially in Western Amazon. This thesis aims to fill this gap by addressing

  4. Implications of climate change for water resources in the Great Lakes basin

    International Nuclear Information System (INIS)

    Clamen, M.

    1990-01-01

    Several authors have suggested the following impacts of global warming for the Great Lakes region. The average annual warming is predicted by one model to be ca 4.5 degree C, slightly more in winter and slightly less in summer. Annual precipitation is projected to increase by ca 8% for points in the central and western basin, but to decrease by 3-6% for the eastern basin. Basin snowpack could be reduced by up to 100% and the snow season shortened by 2-4 weeks, resulting in a reduction of more than 50% in available soil moisture. Buoyancy-driven turnovers of the water column on four of the six lakes may not occur at all. Presently the phenomena occurs twice per year on all the lakes. Ice formation would be greatly reduced. Maximum ice cover may decline from 72-0% for Lake Superior, 38-0% for Lake Michigan, 65-0% for Lake Huron, 90-50% for Lake Erie and 33-0% for Lake Ontario. Net basin supplies would be reduced probably in the range 15-25% below the current mean value. Possible responses include integrated studies and research, better and continually updated information, assessment of public policies in the U.S. and Canada, enhanced private planning efforts, and increased global cooperation

  5. Sulphur extended oil sand mix : paving material for lower transport cost and CO{sub 2} reduction : ASRL Syncrude research project 1995

    Energy Technology Data Exchange (ETDEWEB)

    Aquin d' , G. [Con-Sul Inc., Missoula, MT (United States)

    2010-07-01

    This power point presentation discussed the use of sulphur-enhanced oil sands (SEOS) as a paving mixture. Sulphur has been added to asphaltic bitumen paving processes since the 1850s. Research into sulphur additions has been conducted by various Canadian industry members and institutions. A study in 1995 investigated the use of SEOS as a temporary paving material. The benefits of using SEOS included lower capital costs and lower greenhouse gas (GHG) impacts. Increases in equipment efficiency were also observed. Researchers are now developing mixing protocols and testing various paving materials in relation to temperature regimes and percentages of sulphur. Sand, limestone, coke, and rubber additions are also being evaluated, as well as the behaviour of SEOS in freeze-thaw cycles. To date, the studies have indicated that a 30 percent sulphur, 10 percent sand, and 60 percent oil sand mixture provides optimal compression and behaviour under freeze-thaw conditions. The use of SEOS paving at oil sands mine sites will reduce truck and road maintenance as well as reduce fuel emissions and consumption rates. tabs., figs.

  6. Dynamics of biogeochemical sulfur cycling in Mono Lake

    Science.gov (United States)

    Phillips, A. A.; Fairbanks, D.; Wells, M.; Fullerton, K. M.; Bao, R.; Johnson, H.; Speth, D. R.; Stamps, B. W.; Miller, L.; Sessions, A. L.

    2017-12-01

    Mono Lake, California is a closed-basin soda lake (pH 9.8) with high sulfate (120mM), and is an ideal natural laboratory for studying microbial sulfur cycling. Mono Lake is typically thermally stratified in summer while mixing completely in winter. However, large snowmelt inputs may induce salinity stratification that persists for up to five years, causing meromixis. During the California drought of 2014-16, the lake has mixed thoroughly each winter, but the abundant 2017 snowmelt may usher in a multi-year stratification. This natural experiment provides an opportunity to investigate the temporal relationship between microbial sulfur cycling and lake biogeochemistry. We analyzed water samples from five depths at two stations in May of 2017, before the onset of meromixis. Water column sulfate isotope values were generally constant with depth, centering at a δ34SVCDT of 17.39 ± 0.06‰. Organic sulfur isotopes were consistently lighter than lake sulfate, with a δ34SVCDT of 15.59 ± 0.56‰. This significant offset between organic and inorganic sulfur contradicts the minimal isotope effect associated with sulfate assimilation. Sediment push core organic values were further depleted, ranging between δ34SVCDT of -8.94‰ and +0.23‰, implying rapid turnover of Mono Lake sulfur pools. Both lipid biomarkers and 16S rRNA gene amplicons identify Picocystis salinarum, a unicellular green alga, as the dominant member of the microbial community. However, bacterial biomarkers and 16S rRNA genes point to microbes capable of sulfur cycling. We found that dsrA increased with depth (R2 = 0.9008, p reducers and sulfide oxidizers after >1 year of stratification. We saw no evidence in May of 2017 of sulfate reducing bacteria across the oxycline. Additionally, no sulfide was detectable in lake bottom waters despite oxygen below 6.25 µM. Preliminary results suggest a dynamic interplay between sulfide oxidation, sulfate reduction, and the onset of lake stratification. Additional

  7. Principles of lake sedimentology

    International Nuclear Information System (INIS)

    Janasson, L.

    1983-01-01

    This book presents a comprehensive outline on the basic sedimentological principles for lakes, and focuses on environmental aspects and matters related to lake management and control-on lake ecology rather than lake geology. This is a guide for those who plan, perform and evaluate lake sedimentological investigations. Contents abridged: Lake types and sediment types. Sedimentation in lakes and water dynamics. Lake bottom dynamics. Sediment dynamics and sediment age. Sediments in aquatic pollution control programmes. Subject index

  8. Late Quaternary landscape development at the margin of the Pomeranian phase (MIS 2) near Lake Wygonin (Northern Poland)

    Science.gov (United States)

    Hirsch, Florian; Schneider, Anna; Nicolay, Alexander; Błaszkiewicz, Mirosław; Kordowski, Jarosław; Noryskiewicz, Agnieszka M.; Tyszkowski, Sebastian; Raab, Alexandra; Raab, Thomas

    2015-04-01

    In Central Europe, Late Quaternary landscapes experienced multiple phases of geomorphologic activity. In this study,we used a combined geomorphological, pedological, sedimentological and palynological approach to characterize landscape development after the Last Glacial Maximum (LGM) near Lake Wygonin in Northern Poland. The pedostratigraphical findings from soil pits and drillings were extrapolated using ground-penetrating radar (GPR) and electric resistivity tomography (ERT). During the Pomeranian phase, glacial and fluvioglacial processes dominated the landscape near Lake Wygonin. At the end of the glacial period, periglacial processes became relevant and caused the formation of ventifacts and coversands containing coated sand grains. At approximately 15,290-14,800 cal yr BP, a small pond formed in a kettle hole (profile BWI2). The lacustrine sediments lack eolian sand components and therefore indicate the decline of eolian processes during that time. The increase of Juniperus and rock-rose (Helianthemum) in the pollen diagram is a prominent marker of the Younger Dryas. At the end of the Younger Dryas, a partial reshaping of the landscape is indicated by abundant charcoal fragments in disturbed lake sediments. No geomorphologic activity since the beginning of the Holocene is documented in the terrestrial and wetland archives. The anthropogenic impact is reflected in the pollen diagram by the occurrence of rye pollen grains (Cerealia type, Secale cereale) and translocated soil sediments dated to 1560-1410 cal yr BP, proving agricultural use of the immediate vicinity. With the onset of land use, gully incision and the accumulation of colluvial fans reshaped the landscape locally. Since 540-460 cal yr BP, further gully incision in the steep forest tracks has been associated with the intensification of forestry. Outside of the gully catchments, the weakly podzolized Rubic Brunic Arenosols show no features of Holocene soil erosion. Reprinted from CATENA, Volume 124

  9. Distribution and behavior of radionuclides and stable elements in Lake Obuchi

    International Nuclear Information System (INIS)

    Ueda, Shinji; Hasegawa, Hidenao; Hisamatsu, Shun'ichi; Inaba, Jiro

    2000-01-01

    Distribution and behavior of radionuclides and related stable elements in the lake water of brackish Lake Obuchi were investigated by field observations. Concentrations of 238 U and stable elements were measured at various points in the lake, and compiled to obtain the elemental distributions and variation characteristics. The concentrations of 238 U in the lake water were higher in areas nearer to the Pacific Ocean, and correlated well with those of Na, K, Ca, Mg and Sr (r = 0.86 to 0.92). These observations implied that 238 U in the lake originated from seawater. The bottom layer water was reductive during July and September (stratified period) in deep areas (> 3 m). In this condition, concentrations of PO 4 3- -P, NH 4 + -N, Fe and Mn in the water increased. Concentration ratios of 238 U to those of Na strongly suggested the following conclusions. The concentrations of 238 U in the turn-over period were represented by a simple mixture of seawater and fresh water. However, in the stratified period, part of the 238 U was lost from the seawater near the bottom of the lake due to the reductive condition. (author)

  10. Distribution and behavior of radionuclides and stable elements in Lake Obuchi

    International Nuclear Information System (INIS)

    Ueda, Shinji; Hasegawa, Hidenao; Takaku, Yuichi; Kondo, Kunio; Inaba, Jiro

    2001-01-01

    This investigation focused on the relationship between the uranium concentration and organic matter in the lake water and the bottom sediment of Lake Obuchi, Rokkasho Village, Aomori. Concentrations of 238 U and organic matter were measured at various points in the lake, and compiled to obtain the distributions and variation characteristics. Concentrations of dissolved organic carbon (DOC) in the lake water were approximately 1.8 mg l -1 . In contrast, these concentrations were low (0.5 mg l -1 ) in Futamata River. The relationship between the concentrations of 238 U and DOC in the lake water did not have a significant correlation. However, there was a close relationship (r=-0.87) between the ratios of 238 U/salinity and DOC in the bottom layer water. Moreover, a relationship between concentration of uranium and total organic carbon in core sediment had a significant correlation (r=0.80). These results suggest that uranium was reduced from a stable form +6 valence from to an unstable +4 valence form and was removed from the lake water, after the consumption of O 2 accompanied by the decomposition of the organic matter in sediment caused chemical reduction in the bottom layer. (author)

  11. Trajectories of saltating sand particles behind a porous fence

    Science.gov (United States)

    Zhang, Ning; Lee, Sang Joon; Chen, Ting-Guo

    2015-01-01

    Trajectories of aeolian sand particles behind a porous wind fence embedded in a simulated atmospheric boundary layer were visualized experimentally, to investigate the shelter effect of the fence on sand saltation. Two sand samples, one collected from a beach (d = 250 μm) and the other from a desert (d = 100 μm), were tested in comparison with the previous studies of a 'no-fence' case. A wind fence (ε = 38.5%) was installed on a flat sand bed filled with each sand sample. A high-speed photography technique and the particle tracking velocimetry (PTV) method were employed to reconstruct the trajectories of particles saltating behind the fence. The collision processes of these sand particles were analyzed, momentum and kinetic energy transfer between saltating particles and ground surface were also investigated. In the wake region, probability density distributions of the impact velocities agree well with the pattern of no-fence case, and can be explained by a log-normal law. The horizontal component of impact velocity for the beach sand is decreased by about 54%, and about 76% for the desert sand. Vertical restitution coefficients of bouncing particles are smaller than 1.0 due to the presence of the wind fence. The saltating particles lose a large proportion of their energy during the collision process. These results illustrate that the porous wind fence effectively abates the further evolution of saltating sand particles.

  12. Hydrology, water quality, and nutrient loads to the Bauman Park Lake, Cherry Valley, Winnebago County, Illinois, May 1996-April 1997

    Science.gov (United States)

    Kay, Robert T.; Trugestaad, Aaron

    1998-01-01

    The Bauman Park Lake occupies a former sand and gravel quarry in the Village of Cherry Valley, Illinois. The lake is eutrophic, and nuisance growths of algae and aquatic macrophytes are supported by nutrients (nitrogen and phosphorus) that are derived primarily from ground-water inflow, the main source of water for the lake. The lake has an average depth of about 18 feet, a maximum depth of about 28 feet, and a volume of 466 acre-feet at a stage of about 717 feet above sea level. The lake also is subject to thermal stratification, and although most of the lake is well oxidized, nearly anoxic conditions were present at the lake bottom during part of the summer of 1996. 4,648 pounds of nitrogen compounds were added to the Bauman Park Lake from May 1996 through April 1997. Phosphorus compounds were derived primarily from inflow from ground water (68.7 percent), sediments derived from shoreline erosion (15.6 percent), internal regeneration (11.7 percent), waterfowl excrement (1.6 percent), direct precipitation and overland runoff (1.2 percent), and particulate matter deposited from the atmosphere (1.2 percent). Nitrogen compounds were derived from inflow from ground water (62.1 percent), internal regeneration (19.6 percent), direct precipitation and overland runoff (10.1 percent), particulate matter deposited from the atmosphere (3.5 percent), sediments derived from shoreline erosion (4.4 percent), and waterfowl excrement (0.3 percent). About 13 pounds of phosphorus and 318 pounds of nitrogen compounds flow out of the lake to ground water. About 28 pounds of nitrogen is removed by denitrification. Algae and aquatic macrophytes utilize nitrate, nitrite, ammonia, and dissolved phosphorus. The availability of dissolved phosphorus in the lake water controls algal growth. Uptake of the nutrients, by aquatic macrophytes and algae, temporarily removes nutrients from the water column but not from the lake basin. Because the amount of nutrients entering the lake greatly exceeds

  13. The ecology and impact of the invasion of Lake Ontario by the zebra mussel (Dreissena polymorpha) and quagga mussel (D. bugensis)

    Science.gov (United States)

    Negley, T.L.; Mills, E.L.; Baldwin, B.; O'Gorman, R.; Owens, R.W.; Munawar, M.

    2003-01-01

    In this chapter we present a detailed description of the zebra and quagga mussel invasion in Lake Ontario, with specific emphasis on: (1) the development of the Dreissena populations in Lake Ontario, (2) previously unreported data from 1997 and 1998 for Dreissena populations at Nine-Mile Point in Lake Ontario, (3) factors influencing dreissenid development in Lake Ontario, and (4) the effects of dreissenid colonization on the biota of the Lake Ontario ecosystem.

  14. Contribution to the study of sedimentation rates in some french Polynesian lakes and lagoon

    International Nuclear Information System (INIS)

    Serra, C.; Poletiko, C.; Badie, C.

    1991-03-01

    210 Pb measurements using 210 Po deposition technique were performed in several marine and lacustrine sediments of French Polynesia to determine sedimentation rates in lakes and lagoons. Some results in terrigeneous sediments were acceptable and permit rate measurements; on the contrary other sediments, especially coral sands provided a 210 Pb/ 226 Ra disequilibrium (0.33 to 0.69). The occurring phenomena seem to be related to 222 Rn scavenging and geothermal endoupwelling which induces 226 Ra enhancement; this leads to the same 210 Pb/ 226 Ra disequilibrium as in deep ocean waters as described, for instance by Thomson and Turekian (1976) in an upwelling zone on Peru coasts [fr

  15. Development of a macrophyte-based index of biotic integrity for Minnesota lakes

    Science.gov (United States)

    Beck, M.W.; Hatch, L.K.; Vondracek, B.; Valley, R.D.

    2010-01-01

    Traditional approaches for managing aquatic resources have often failed to account for effects of anthropogenic disturbances on biota that are not directly reflected by chemical and physical proxies of environmental condition. The index of biotic integrity (IBI) is a potentially effective assessment method to integrate ecological, functional, and structural aspects of aquatic systems. A macrophyte-based IBI was developed for Minnesota lakes to assess the ability of aquatic plant communities to indicate environmental condition. The index was developed using quantitative point intercept vegetation surveys for 97 lakes that represent a range of limnological and watershed characteristics. We followed an approach similar to that used in Wisconsin to develop the aquatic macrophyte community index (AMCI). Regional adaptation of the AMCI required the identification of species representative of macrophyte communities in Minnesota. Metrics and scaling methods were also substantially modified to produce a more empirically robust index. Regression analyses indicated that IBI scores reflected statewide differences in lake trophic state (R2 = 0.57, F = 130.3, df = 1, 95, p indicated a unique response of the IBI to human-induced stress separate from a response to natural lake characteristics. The IBI was minimally affected by differences in sample point density as indicated by Monte Carlo analyses of reduced sampling effort. Our analysis indicates that a macrophyte IBI calibrated for Minnesota lakes could be useful for identifying differences in environmental condition attributed to human-induced stress gradients. ?? 2010 Elsevier Ltd.

  16. Biodegradable materials as binders for IVth generation moulding sands

    OpenAIRE

    K. Major-Gabry

    2015-01-01

    This paper focuses on the possibility of using the biodegradable materials as binders (or parts of binders?compositions) for foundry moulding and core sands. Results showed that there is a great possibility of using available biodegradable materials as foundry moulding sand binders. Using biodegradable materials as partial content of new binders, or additives to moulding sands may not only decrease the toxicity and increase reclamation ability of tested moulding sands, but also accelerate the...

  17. Classification of sand samples according to radioactivity content by the use of euclidean and rough sets techniques

    International Nuclear Information System (INIS)

    Abd El-Monsef, M.M.; Kozae, A.M.; Seddeek, M.K.; Medhat, T.; Sharshar, T.; Badran, H.M.

    2004-01-01

    Form the geological point of view, the origin and transport of black and normal sands is particularly important. Black and normal sands came to their places along the Mediterranean-sea coast after transport by some natural process. Both types of sands have different radiological properties. This study is, therefore, attempts to use mathematical methods to classify Egyptian sand samples collected from 42 locations in an area of 40 x 19 km 2 based on their radioactivity contents. The use of all information resulted from the experimental measurements of radioactivity contents as well as some other parameters can be a time and effort consuming task. So that the process of eliminating unnecessary attributes is of prime importance. This elimination process of the superfluous attributes that cannot affect the decision was carried out. Some topological techniques to classify the information systems resulting from the radioactivity measurements were then carried out. These techniques were applied in Euclidean and quasi-discrete topological cases. While there are some applications in environmental radioactivity of the former case, the use of the quasi-discrete in the so-called rough set information analysis is new in such a study. The mathematical methods are summarized and the results and their radiological implications are discussed. Generally, the results indicate no radiological anomaly and it supports the hypothesis previously suggested about the presence of two types of sand in the studied area

  18. Lake Afdera: a threatened saline lake in Ethiopia | Getahun | SINET ...

    African Journals Online (AJOL)

    Lake Afdera is a saline lake located in the Afar region, Northern Ethiopia. Because of its inaccessibility it is one of the least studied lakes of the country. It supports life including three species of fish of which two are endemic. Recently, reports are coming out that this lake is used for salt extraction. This paper gives some ...

  19. The Canadian oil sands--a sticky future

    Energy Technology Data Exchange (ETDEWEB)

    Cowtan, S A

    1977-01-01

    The oil sands have been known for 200 yr but only over the last decade have they been recognized as a potential major energy source for Canada. The study looks at the present GCOS plant, and briefly discusses Canada's future energy requirements and how she might fill those requirements from conventional and nonconventional sources, such as the Frontier areas, oil sands mining, oil sands in situ, and heavy oil. The economics and the future of these sources and the environment necessary for their development are analyzed.

  20. Paleolimnological assessment of riverine and atmospheric pathways and sources of metal deposition at a floodplain lake (Slave River Delta, Northwest Territories, Canada)

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, Lauren A., E-mail: L7macdon@uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Wiklund, Johan A. [Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Elmes, Matthew C.; Wolfe, Brent B. [Department of Geography and Environmental Studies, Wilfrid Laurier University, Waterloo, ON N2L 3C5 (Canada); Hall, Roland I., E-mail: rihall@uwaterloo.ca [Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1 (Canada)

    2016-02-15

    Growth of natural resource development in northern Canada has raised concerns about the effects on downstream aquatic ecosystems, but insufficient knowledge of pre-industrial baseline conditions continues to undermine ability of monitoring programs to distinguish industrial-derived contaminants from those supplied by natural processes. Here, we apply a novel paleolimnological approach to define pre-industrial baseline concentrations of 13 priority pollutant metals and vanadium and assess temporal changes, pathways and sources of these metals at a flood-prone lake (SD2) in the Slave River Delta (NWT, Canada) located ~ 500 km north of Alberta's oil sands development and ~ 140 km south of a former gold mine at Yellowknife, NWT. Results identify that metal concentrations, normalized to lithium concentration, are not elevated in sediments deposited during intervals of high flood influence or low flood influence since onset of oil sands development (post-1967) relative to the 1920–1967 baseline established at SD2. When compared to a previously defined baseline for the upstream Athabasca River, several metal-Li relations (Cd, Cr, Ni, Zn, V) in post-1967 sediments delivered by floodwaters appear to plot along a different trajectory, suggesting that the Peace and Slave River watersheds are important natural sources of metal deposition at the Slave River Delta. However, analysis revealed unusually high concentrations of As deposited during the 1950s, an interval of very low flood influence at SD2, which corresponded closely with emission history of the Giant Mine gold smelter indicating a legacy of far-field atmospheric pollution. Our study demonstrates the potential for paleolimnological characterization of baseline conditions and detection of pollution from multiple pathways in floodplain ecosystems, but that knowledge of paleohydrological conditions is essential for interpretation of contaminant profiles. - Highlights: • We examine metal depositional history at a

  1. Converting an estuary to Lake Grevelingen: Environmental review of a coastal engineering project

    Science.gov (United States)

    Saeijs, H. L. F.; Stortelder, P. B. M.

    1982-09-01

    To guarantee protection from storm floods in the southwestern part of the Netherlands, the length of exposed coastline is being greatly reduced by the construction of dams and a storm surge barrier. As part of the Delta Project, the mouth of the Grevelingen estuary was closed in 1971. Due to the closure, tidal movement was eliminated, which resulted in changes in environmental factors such as transparency and chloride and phosphate concentration. The number of plant and animal groups decreased. Large areas of sand flats and salt marshes, which were formerly exposed to the tides, were left “high and dry.” This resulted in enormous changes for the communities living in these areas. The development of a new ecological system and the changed potential afforded by the water and land areas for human use, emphasized the need for physical planning. The potential uses (functions) of the new system are discussed in this article. Special attention is given to the demand for recreational facilities and nature conservation and to the balanced realization of these main functions. The methods applied in choosing between alternatives in physical planning are explained. Water quality and ecosystem management are discussed. One of the main management objectives is the prevention of a further decrease in the chloride concentration and the number of species. A sluice was, therefore, put into operation in 1978, by means of which water was exchanged between the North Sea and Lake Grevelingen. The responses observed are discussed here. In the near future, a crucial decision will have to be made: Will Lake Grevelingen remain a salt-water lake or will it become a fresh-water lake?

  2. Assessing Insecticide Susceptibility of Laboratory Lutzomyia longipalpis and Phlebotomus papatasi Sand Flies (Diptera: Psychodidae: Phlebotominae).

    Science.gov (United States)

    Denlinger, David S; Lozano-Fuentes, Saul; Lawyer, Phillip G; Black, William C; Bernhardt, Scott A

    2015-09-01

    Chemical insecticides are effective for controlling Lutzomyia and Phlebotomus sand fly (Diptera: Psychodidae) vectors of Leishmania parasites. However, repeated use of certain insecticides has led to tolerance and resistance. The objective of this study was to determine lethal concentrations (LCs) and lethal exposure times (LTs) to assess levels of susceptibility of laboratory Lutzomyia longipalpis (Lutz and Nieva) and Phlebotomus papatasi (Scopoli) to 10 insecticides using a modified version of the World Health Organization (WHO) exposure kit assay and Centers for Disease Control and Prevention (CDC) bottle bioassay. Sand flies were exposed to insecticides coated on the interior of 0.5-gallon and 1,000-ml glass bottles. Following exposure, the flies were allowed to recover for 24 h, after which mortality was recorded. From dose-response survival curves for L. longipalpis and P. papatasi generated with the QCal software, LCs causing 50, 90, and 95% mortality were determined for each insecticide. The LCs and LTs from this study will be useful as baseline reference points for future studies using the CDC bottle bioassays to assess insecticide susceptibility of sand fly populations in the field. There is a need for a larger repository of sand fly insecticide susceptibility data from the CDC bottle bioassays, including a range of LCs and LTs for more sand fly species with more insecticides. Such a repository would be a valuable tool for vector management. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Water quality of Lake Austin and Town Lake, Austin, Texas

    Science.gov (United States)

    Andrews, Freeman L.; Wells, Frank C.; Shelby, Wanda J.; McPherson, Emma

    1988-01-01

    Lake Austin and Town Lake are located on the Colorado River in Travis County, central Texas, and serve as a source of water for municipal and industrial water supplies, electrical-power generation, and recreation for more than 500,000 people in the Austin metropolitan area. Lake Austin, located immediately downstream of Lake Travis, extends for more than 20 miles into the western edge of the city of Austin. Town Lake extends through the downtown area of the city of Austin for nearly 6 miles where the Colorado River is impounded by Longhorn Dam.

  4. Thermoluminescent dosimetric properties of Descalvado sand

    International Nuclear Information System (INIS)

    Teixeira, M.I.; Caldas, L.V.E.

    2006-01-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ( 60 Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  5. Thermoluminescent dosimetric properties of Descalvado sand

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, M.I.; Caldas, L.V.E

    2006-07-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ({sup 60} Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  6. Late Holocene Lake Level Fluctuations at Laguna Arapa, Peru and Connections to Human Demography

    Science.gov (United States)

    Hillman, A. L.; Abbott, M. B.; Werne, J. P.; Arkush, E.; Thompson, L. G.; Ferland, T.; Holmes, E.; Puhnaty, C.; Woods, A.

    2016-12-01

    The relationship between variations in hydroclimate and human demography on the Peruvian Altiplano has significant implications for understanding how people in the past have adapted to changes in freshwater resources. To investigate these human-environmental interactions, this project presents a 2,000 year sediment record from Laguna Arapa, a large lake that is Titicaca. Using sedimentology and stratigraphy as well as a suite of organic geochemical proxies including fecal 5β-stanols and leaf waxes (long chain n-alkanoic acids), we aim to tie together proxies of human population with indicators of regional hydroclimate. Preliminary results of sedimentology and stratigraphy show notable transitions from sand to silt to clay, suggesting rising lake level sequences at 500 and 700 AD. The last 1,300 years of sediment are characterized by alternating layers of organic rich material with abundant charcoal and black inorganic clay, suggesting intermittent periods of aridity and/or anthropogenic fire-setting. These layers are particularly frequent during the Medieval Climate Anomaly, which was characterized by dry and warm conditions. These results agree well with other records of hydroclimate from regional lakes as well as accumulation rate and temperature from the Quelccaya ice cap. Organic geochemical work is currently in progress and shows promise for linking together proxies of human demography with hydroclimate to understand the relationship between human settlement and climate change.

  7. Modeling Prairie Pothole Lakes: Linking Satellite Observation and Calibration (Invited)

    Science.gov (United States)

    Schwartz, F. W.; Liu, G.; Zhang, B.; Yu, Z.

    2009-12-01

    This paper examines the response of a complex lake wetland system to variations in climate. The focus is on the lakes and wetlands of the Missouri Coteau, which is part of the larger Prairie Pothole Region of the Central Plains of North America. Information on lake size was enumerated from satellite images, and yielded power law relationships for different hydrological conditions. More traditional lake-stage data were made available to us from the USGS Cottonwood Lake Study Site in North Dakota. A Probabilistic Hydrologic Model (PHM) was developed to simulate lake complexes comprised of tens-of-thousands or more individual closed-basin lakes and wetlands. What is new about this model is a calibration scheme that utilizes remotely-sensed data on lake area as well as stage data for individual lakes. Some ¼ million individual data points are used within a Genetic Algorithm to calibrate the model by comparing the simulated results with observed lake area-frequency power law relationships derived from Landsat images and water depths from seven individual lakes and wetlands. The simulated lake behaviors show good agreement with the observations under average, dry, and wet climatic conditions. The calibrated model is used to examine the impact of climate variability on a large lake complex in ND, in particular, the “Dust Bowl Drought” 1930s. This most famous drought of the 20th Century devastated the agricultural economy of the Great Plains with health and social impacts lingering for years afterwards. Interestingly, the drought of 1930s is unremarkable in relation to others of greater intensity and frequency before AD 1200 in the Great Plains. Major droughts and deluges have the ability to create marked variability of the power law function (e.g. up to one and a half orders of magnitude variability from the extreme Dust Bowl Drought to the extreme 1993-2001 deluge). This new probabilistic modeling approach provides a novel tool to examine the response of the

  8. Proposal to evaluate the use of ERTS-1 imagery in mapping and managing soil and range resources in the Sand Hills region of Nebraska

    Science.gov (United States)

    Drew, J. V. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Increase in radiance values is directly related to decrease in vegetative biomass, though not in a linear manner. Should the relationship hold true over an entire growing season, this would allow an extremely rapid evaluation of range condition. Computer access by remote terminal would allow production of this type of range condition evaluation in near real time, which is essential if grazing practice decisions are to be made based on satellite imagery acquisition. Negating the manipulation of photographic products appears to be the logical way to provide satellite imagery data to the user in near real time. There appears to be a direct linear relationship between radiance values of bands 4 and 5 and increase in total inorganic ions (6 ions) of lakes in the Sand hills region. Consistent ion concentration of lakes during the year could allow their radiance values to serve as a means of equating radiance values from image to image.

  9. A qualitative evaluation of long-term processes governing the behaviour of uranium mill tailings placed in deep lakes

    International Nuclear Information System (INIS)

    1982-03-01

    The emplacement of uranium mill tailings in deep lakes may provide an acceptable method of tailings disposal at certain sites in Canada. Disposal in a depositional environment typical of deep lakes appears to offer greater prospects for long-term stability than present methods of land-based management. From the regulatory point of view, it is necessary to know which factors should be taken into account in assessing the acceptability of such an approach. This report examines the environmental variables governing the behaviour of radionuclides and trace elements in the groundwater systems, lake water, and finally in the biosphere over the short and long term. Physical, chemical and biological factors are each considered. Conclusions are presented in terms of points for and against disposal in deep lakes. This report summarizes the data and conclusions presented in an annex volume

  10. Mitigating in situ oil sands carbon costs

    Energy Technology Data Exchange (ETDEWEB)

    Theriault, D.J.; Peterson, J. [Laricina Energy Ltd., Calgary, AB (Canada); Heinrichs, H. [Canadian Chemical Technology Inc., Calgary, AB (Canada)

    2008-10-15

    Carbon capture and sequestration is a complex problem with a variety of dimensions that need to be considered. The political, social, and regulatory pressures are forcing carbon costs on the oil sands industry in an effort to reduce the carbon footprint of oil sands operations. This paper reviewed the political, social, and regulatory pressures and obligations for the in-situ oil sands industry. It presented the views and insights of Laricina Energy on the carbon challenge. It also described the initiatives that Laricina Energy is taking to manage these imperatives and outlined the challenges the industry is facing. The purpose of the paper was to encourage dialogue and collaboration by the oil sands industry. The paper also described the dimensions of the carbon problem and how the industry can contribute to a solution. Last, the paper reviewed the parameters of carbon dioxide or greenhouse gas containment and storage issues. It was concluded that the regulatory and policy requirements need to be clarified so that industry understands the new business landscape as well as the requirements that influence the economics of in-situ oil sands development. 7 refs., 7 figs.

  11. Refuge Lake Reclassification in 620 Minnesota Cisco Lakes under Future Climate Scenarios

    Directory of Open Access Journals (Sweden)

    Liping Jiang

    2017-09-01

    Full Text Available Cisco (Coregonus artedi is the most common coldwater stenothermal fish in Minnesota lakes. Water temperature (T and dissolved oxygen (DO in lakes are important controls of fish growth and reproduction and likely change with future climate warming. Built upon a previous study, this study uses a modified method to identify which of 620 cisco lakes in Minnesota can still support cisco populations under future climate and therefore be classified as cisco refuge lakes. The previous study used oxythermal stress parameter TDO3, the temperature at DO of 3 mg/L, simulated only from deep virtual lakes to classify 620 cisco lakes. Using four categories of virtual but representative cisco lakes in modified method, a one-dimensional water quality model MINLAKE2012 was used to simulate daily T and DO profiles in 82 virtual lakes under the past (1961–2008 and two future climate scenarios. A multiyear average of 31-day largest TDO3 over variable benchmark (VB periods, AvgATDO3VB, was calculated from simulated T and DO profiles using FishHabitat2013. Contour plots of AvgATDO3VB for four categories of virtual lakes were then developed to reclassify 620 cisco lakes into Tier 1 (AvgATDO3VB < 11 °C or Tier 2 refuge lakes, and Tier 3 non-refuge lakes (AvgATDO3VB > 17 °C. About 20% of 620 cisco lakes are projected to be refuge lakes under future climate scenarios, which is a more accurate projection (improving the prediction accuracy by ~6.5% from the previous study since AvgATDO3VB was found to vary by lake categories.

  12. R/S analysis based study on long memory about CODMn in Poyang Lake Inlet and Outlet

    Science.gov (United States)

    Wang, Lili

    2018-02-01

    Rescaled range analysis (R/S) is applied to the long memory behavior analysis of water CODMn series in Poyang Lake Inlet and Outlet in China. The results show that these CODMn series are characterized by long memory, and the characteristics have obvious differences between the Lake Inlet and Outlet. Our findings suggest that there was an obvious scale invariance, namely CODMn series in Lake Inlet for 13 weeks and CODMn in Lake Outlet for 17 weeks. Both displayed a two-power-law distribution and a similar high long memory. We made a preliminary explanation for the existence of the boundary point tc , using self-organized criticality. This work can be helpful to improvement of modelling of lake water quality.

  13. Watershed vs. within-lake drivers of nitrogen: phosphorus dynamics in shallow lakes.

    Science.gov (United States)

    Ginger, Luke J; Zimmer, Kyle D; Herwig, Brian R; Hanson, Mark A; Hobbs, William O; Small, Gaston E; Cotner, James B

    2017-10-01

    Research on lake eutrophication often identifies variables affecting amounts of phosphorus (P) and nitrogen (N) in lakes, but understanding factors influencing N:P ratios is important given its influence on species composition and toxin production by cyanobacteria. We sampled 80 shallow lakes in Minnesota (USA) for three years to assess effects of watershed size, proportion of watershed as both row crop and natural area, fish biomass, and lake alternative state (turbid vs. clear) on total N : total P (TN : TP), ammonium, total dissolved phosphorus (TDP), and seston stoichiometry. We also examined N:P stoichiometry in 20 additional lakes that shifted states during the study. Last, we assessed the importance of denitrification by measuring denitrification rates in sediment cores from a subset of 34 lakes, and by measuring seston δ 15 N in four additional experimental lakes before and after they were experimentally manipulated from turbid to clear states. Results showed alternative state had the largest influence on overall N:P stoichiometry in these systems, as it had the strongest relationship with TN : TP, seston C:N:P, ammonium, and TDP. Turbid lakes had higher N at given levels of P than clear lakes, with TN and ammonium 2-fold and 1.4-fold higher in turbid lakes, respectively. In lakes that shifted states, TN was 3-fold higher in turbid lakes, while TP was only 2-fold higher, supporting the notion N is more responsive to state shifts than is P. Seston δ 15 N increased after lakes shifted to clear states, suggesting higher denitrification rates may be important for reducing N levels in clear states, and potential denitrification rates in sediment cores were among the highest recorded in the literature. Overall, our results indicate lake state was a primary driver of N:P dynamics in shallow lakes, and lakes in clear states had much lower N at a given level of P relative to turbid lakes, likely due to higher denitrification rates. Shallow lakes are often

  14. Evaporite deposition in a shallow perennial lake, Qaidam basin, western China

    Energy Technology Data Exchange (ETDEWEB)

    Schubel, K.A.; Lowenstein, T.K. (SUNY, Binghampton, NY (United States)); Spencer, R.J. (Univ. of Calgary, Alberta (Canada)); Pengxi, Z. (Institute of Salt Lakes, Xining (China))

    1991-03-01

    Evaporites accumulate in ephemeral saline-pans, shallow perennial lakes or lagoons, and deep perennial systems. Continuous brine trench exposures of Holocene evaporites from the Qaidam basin provide criteria for the recognition of shallow perennial lake sediments. Based on Landsat photographs, lateral extent of beds (at least 7 km), and sequence thicknesses (maximum 2.5 m), the paleolake is interpreted to have been less than 2.5 m deep and at least 120 km{sup 2} in area. Sediments consist of laminated siliciclastic mud overlain by mud-halite couplets (mm- to cm-scale layers), which represent one vertical shallowing- and concentrating-upwards sequence. The basal laminite marks the onset of deposition in this shallow perennial paleolake. Syndepositional halite textures and fabrics in the overlying mud-halite couplets include cumulates, rafts, and chevrons, draped by mud laminae, and halite layers truncated by horizontal dissolution surfaces (increasing in frequency upwards). Paleolake brines, determined from fluid inclusion melting temperatures, are Na-Mg-Cl-rich and evolve from 0.84 m Mg{sup 2} to 1.52 m Mg{sup 2+} (near the surface). Combinations of the following criteria may be used for the recognition of shallow, nonstratified, perennial lake sediments: lateral continuity of layers; muds undisrupted by subaerial exposure; vertical bottom-growth of halite; halite layers conformably overlain by mud; halite layers truncated by nonuniformly spaced horizontal dissolution surfaces; erosional scours and channels filled with cross-laminated gypsum, halite, and siliciclastic sand and mud; and salinity fluctuations over small stratigraphic intervals within an overall concentrating-upwards sequence.

  15. Changes in Rongbuk lake and Imja lake in the Everest region of Himalaya

    Science.gov (United States)

    Chen, W.; Doko, T.; Liu, C.; Ichinose, T.; Fukui, H.; Feng, Q.; Gou, P.

    2014-12-01

    The Himalaya holds the world record in terms of range and elevation. It is one of the most extensively glacierized regions in the world except the Polar Regions. The Himalaya is a region sensitive to climate change. Changes in the glacial regime are indicators of global climate changes. Since the second half of the last century, most Himalayan glaciers have melted due to climate change. These changes directly affected the changes of glacial lakes in the Himalayan region due to the glacier retreat. New glacial lakes are formed, and a number of them have expanded in the Everest region of the Himalayas. This paper focuses on the two glacial lakes which are Imja Lake, located at the southern slope, and Rongbuk Lake, located at the northern slope in the Mt. Everest region, Himalaya to present the spatio-temporal changes from 1976 to 2008. Topographical conditions between two lakes were different (Kruskal-Wallis test, p < 0.05). Rongbuk Lake was located at 623 m higher than Imja Lake, and radiation of Rongbuk Lake was higher than the Imja Lake. Although size of Imja Lake was larger than the Rongbuk Lake in 2008, the growth speed of Rongbuk Lake was accelerating since 2000 and exceeds Imja Lake in 2000-2008. This trend of expansion of Rongbuk Lake is anticipated to be continued in the 21st century. Rongbuk Lake would be the biggest potential risk of glacial lake outburst flood (GLOF) at the Everest region of Himalaya in the future.

  16. A fuzzy approach for modelling radionuclide in lake system

    International Nuclear Information System (INIS)

    Desai, H.K.; Christian, R.A.; Banerjee, J.; Patra, A.K.

    2013-01-01

    Radioactive liquid waste is generated during operation and maintenance of Pressurised Heavy Water Reactors (PHWRs). Generally low level liquid waste is diluted and then discharged into the near by water-body through blowdown water discharge line as per the standard waste management practice. The effluents from nuclear installations are treated adequately and then released in a controlled manner under strict compliance of discharge criteria. An attempt was made to predict the concentration of 3 H released from Kakrapar Atomic Power Station at Ratania Regulator, about 2.5 km away from the discharge point, where human exposure is expected. Scarcity of data and complex geometry of the lake prompted the use of Heuristic approach. Under this condition, Fuzzy rule based approach was adopted to develop a model, which could predict 3 H concentration at Ratania Regulator. Three hundred data were generated for developing the fuzzy rules, in which input parameters were water flow from lake and 3 H concentration at discharge point. The Output was 3 H concentration at Ratania Regulator. These data points were generated by multiple regression analysis of the original data. Again by using same methodology hundred data were generated for the validation of the model, which were compared against the predicted output generated by using Fuzzy Rule based approach. Root Mean Square Error of the model came out to be 1.95, which showed good agreement by Fuzzy model of natural ecosystem. -- Highlights: • Uncommon approach (Fuzzy Rule Base) of modelling radionuclide dispersion in Lake. • Predicts 3 H released from Kakrapar Atomic Power Station at a point of human exposure. • RMSE of fuzzy model is 1.95, which means, it has well imitated natural ecosystem

  17. Lake-wide distribution of Dreissena in Lake Michigan, 1999

    Science.gov (United States)

    Fleischer, Guy W.; DeSorcie, Timothy J.; Holuszko, Jeffrey D.

    2001-01-01

    The Great Lakes Science Center has conducted lake-wide bottom trawl surveys of the fish community in Lake Michigan each fall since 1973. These systematic surveys are performed at depths of 9 to 110 m at each of seven index sites around Lake Michigan. Zebra mussel (Dreissena polymorpha) populations have expanded to all survey locations and at a level to sufficiently contribute to the bottom trawl catches. The quagga (Dreissena bugensis), recently reported in Lake Michigan, was likely in the catches though not recognized. Dreissena spp. biomass ranged from about 0.6 to 15 kg/ha at the various sites in 1999. Dreissenid mussels were found at depths of 9 to 82 m, with their peak biomass at 27 to 46 m. The colonization of these exotic mussels has ecological implications as well as potential ramifications on the ability to sample fish consistently and effectively with bottom trawls in Lake Michigan.

  18. Effective Laboratory Method of Chromite Content Estimation in Reclaimed Sands

    Directory of Open Access Journals (Sweden)

    Ignaszak Z.

    2016-09-01

    Full Text Available The paper presents an original method of measuring the actual chromite content in the circulating moulding sand of foundry. This type of material is applied for production of moulds. This is the case of foundry which most frequently perform heavy casting in which for the construction of chemical hardening mould is used, both the quartz sand and chromite sand. After the dry reclamation of used moulding sand, both types of sands are mixed in various ratios resulting that in reclaimed sand silos, the layers of varying content of chromite in mixture are observed. For chromite recuperation from the circulating moulding sand there are applied the appropriate installations equipped with separate elements generating locally strong magnetic field. The knowledge of the current ratio of chromite and quartz sand allows to optimize the settings of installation and control of the separation efficiency. The arduous and time-consuming method of determining the content of chromite using bromoform liquid requires operational powers and precautions during using this toxic liquid. It was developed and tested the new, uncomplicated gravimetric laboratory method using powerful permanent magnets (neodymium. The method is used in the production conditions of casting for current inspection of chromite quantity in used sand in reclamation plant.

  19. Large Lakes Dominate CO2 Evasion From Lakes in an Arctic Catchment

    Science.gov (United States)

    Rocher-Ros, Gerard; Giesler, Reiner; Lundin, Erik; Salimi, Shokoufeh; Jonsson, Anders; Karlsson, Jan

    2017-12-01

    CO2 evasion from freshwater lakes is an important component of the carbon cycle. However, the relative contribution from different lake sizes may vary, since several parameters underlying CO2 flux are size dependent. Here we estimated the annual lake CO2 evasion from a catchment in northern Sweden encompassing about 30,000 differently sized lakes. We show that areal CO2 fluxes decreased rapidly with lake size, but this was counteracted by the greater overall coverage of larger lakes. As a result, total efflux increased with lake size and the single largest lake in the catchment dominated the CO2 evasion (53% of all CO2 evaded). By contrast, the contribution from the smallest ponds (about 27,000) was minor (evasion at the landscape scale.

  20. Observations of Lake-Breeze Events During the Toronto 2015 Pan-American Games

    Science.gov (United States)

    Mariani, Zen; Dehghan, Armin; Joe, Paul; Sills, David

    2018-01-01

    Enhanced meteorological observations were made during the 2015 Pan and Parapan American Games in Toronto in order to measure the vertical and horizontal structure of lake-breeze events. Two scanning Doppler lidars (one fixed and one mobile), a C-band radar, and a network including 53 surface meteorological stations (mesonet) provided pressure, temperature, humidity, and wind speed and direction measurements over Lake Ontario and urban areas. These observations captured the full evolution (prior, during, and after) of 27 lake-breeze events (73% of observation days) in order to characterize the convective and dynamic processes driving lake breezes at the local scale and mesoscale. The dominant signal of a passing lake-breeze front (LBF) was an increase in dew-point temperature of 2.3 ± 0.3°C, coinciding with a 180° shift in wind direction and a decrease in air temperature of 2.1 ± 0.2°C. Doppler lidar observations over the lake detected lake breezes 1 hour (on average) before detection by radar and mesonet. On days with the synoptic flow in the offshore direction, the lidars observed wedge-shaped LBFs with shallow depths, which inhibited the radar's ability to detect the lake breeze. The LBF's ground speed and inland penetration distance were found to be well-correlated (r = 0.78), with larger inland penetration distances occurring on days with non-opposing (non-offshore) synoptic flow. The observed enhanced vertical motion ({>} 1 m s^{-1}) at the LBF, observed by the lidar on 54% of lake-breeze days, was greater (at times {>} 2.5 m s^{-1}) than that observed in previous studies and longer-lasting over the lake than over land. The weaker and less pronounced lake-breeze structure over land is illustrated in two case studies highlighting the lifetime of the lake-breeze circulation and the impact of propagation distance on lake-breeze intensity.

  1. Fate of Metals in Relation to Water and Sediment Properties in a Subtropical Lake in Central Himalaya, India.

    Science.gov (United States)

    Inaotombi, Shaikhom; Gupta, Prem Kumar

    2017-04-01

    Lakes of Himalaya are one of the most fragile ecosystems on earth. Tourism and urban development in the upland region strongly affect its water resources. The high rate of sedimentation and organic matter deposition alters the ecological state of sediment bed, which indirectly influences on dynamics of metallic elements. We investigated spatial and temporal variations of water and sediment characteristic in Lake Sattal of Central Himalaya, India. Samples were collected seasonally from four sampling locations from January 2011 to December 2012. Pearson's correlation and Canonical correspondence analysis (CCAs) were applied to examine the dynamics and behaviors of heavy metals. Concentrations of elements were in the order of fluoride (Fl) > zinc (Zn) > copper (Cu) > iron (Fe) > manganese (Mn). Sand size fraction was higher in the littoral zone while clay particle was dominant in the profundal zone of the lake. Dissolved oxygen at sediment-water-interface (SWI) and water temperature were the major factors influencing the dynamics of metallic contents in the water column. Spatially, total organic matter (TOM) was higher in the deeper portion of the lake. Our study revealed that mobility of Fe is temperature-dependent, whereas speciation of Mn and Cu are primarily controlled by the suboxic condition of SWI in organic-rich site. Upland lakes are more vulnerable to anoxic condition and have severe implications on heavy metals speciation. Proper implementation of land use policies and management practices, including stormwater detention, can be integrated into resolving such problems.

  2. Lake Michigan lake trout PCB model forecast post audit

    Science.gov (United States)

    Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents th...

  3. Identification of sulfur-cycle prokaryotes in a low-sulfate lake (Lake Pavin) using aprA and 16S rRNA gene markers.

    Science.gov (United States)

    Biderre-Petit, Corinne; Boucher, Delphine; Kuever, Jan; Alberic, Patrick; Jézéquel, Didier; Chebance, Brigitte; Borrel, Guillaume; Fonty, Gérard; Peyret, Pierre

    2011-02-01

    Geochemical researches at Lake Pavin, a low-sulfate-containing freshwater lake, suggest that the dominant biogeochemical processes are iron and sulfate reduction, and methanogenesis. Although the sulfur cycle is one of the main active element cycles in this lake, little is known about the sulfate-reducer and sulfur-oxidizing bacteria. The aim of this study was to assess the vertical distribution of these microbes and their diversities and to test the hypothesis suggesting that only few SRP populations are involved in dissimilatory sulfate reduction and that Epsilonproteobacteria are the likely key players in the oxidative phase of sulfur cycle by using a PCR aprA gene-based approach in comparison with a 16S rRNA gene-based analysis. The results support this hypothesis. Finally, this preliminary work points strongly the likelihood of novel metabolic processes upon the availability of sulfate and other electron acceptors.

  4. A combined CFD-experimental method for developing an erosion equation for both gas-sand and liquid-sand flows

    Science.gov (United States)

    Mansouri, Amir

    The surface degradation of equipment due to consecutive impacts of abrasive particles carried by fluid flow is called solid particle erosion. Solid particle erosion occurs in many industries including oil and gas. In order to prevent abrupt failures and costly repairs, it is essential to predict the erosion rate and identify the locations of the equipment that are mostly at risk. Computational Fluid Dynamics (CFD) is a powerful tool for predicting the erosion rate. Erosion prediction using CFD analysis includes three steps: (1) obtaining flow solution, (2) particle tracking and calculating the particle impact speed and angle, and (3) relating the particle impact information to mass loss of material through an erosion equation. Erosion equations are commonly generated using dry impingement jet tests (sand-air), since the particle impact speed and angle are assumed not to deviate from conditions in the jet. However, in slurry flows, a wide range of particle impact speeds and angles are produced in a single slurry jet test with liquid and sand particles. In this study, a novel and combined CFD/experimental method for developing an erosion equation in slurry flows is presented. In this method, a CFD analysis is used to characterize the particle impact speed, angle, and impact rate at specific locations on the test sample. Then, the particle impact data are related to the measured erosion depth to achieve an erosion equation from submerged testing. Traditionally, it was assumed that the erosion equation developed based on gas testing can be used for both gas-sand and liquid-sand flows. The erosion equations developed in this work were implemented in a CFD code, and CFD predictions were validated for various test conditions. It was shown that the erosion equation developed based on slurry tests can significantly improve the local thickness loss prediction in slurry flows. Finally, a generalized erosion equation is proposed which can be used to predict the erosion rate in

  5. A foundation for the future: building an environmental monitoring system for the oil sands

    International Nuclear Information System (INIS)

    Dowdeswell, L.; Dillon, P.; Ghoshal, S.; Miall, A.; Rasmussen, J.; Smol, J.P.

    2010-12-01

    In September, 2010, important concerns regarding the impacts of oil sand industry on the environment in the Lower Athabasca River Basin resulted in the creation of the oil sands advisory panel. This panel was set up to examine and evaluate the existing system for research and monitoring and identify strengths and weaknesses regarding water monitoring in the Lower Athabasca River Basin and connected waterways. In this report, the panel provides important elements to guide the monitoring of water quality and quantity. The panel has identified several organizations or individuals contributing to the research and monitoring of the Athabasca River system but also points out in the document that the research has not yet led to a consensus regarding the impacts of oil sands development on the environment. It has also been observed that no standardized data management system has been put in place to facilitate the access to data for interested parties. Important weaknesses in the existing monitoring system were identified by the panel. The advisory panel recommended the implementation of a credible and transparent, comprehensive and adaptive monitoring program, through a collaborative work between relevant jurisdictions and stakeholders. 50 refs.

  6. Using Satellite Imagery to Monitor the Major Lakes; Case Study Lake Hamun

    Science.gov (United States)

    Norouzi, H.; Islam, R.; Bah, A.; AghaKouchak, A.

    2015-12-01

    Proper lakes function can ease the impact of floods and drought especially in arid and semi-arid regions. They are important environmentally and can directly affect human lives. Better understanding of the effect of climate change and human-driven changes on lakes would provide invaluable information for policy-makers and local people. As part of a comprehensive study, we aim to monitor the land-cover/ land-use changes in the world's major lakes using satellite observations. As a case study, Hamun Lake which is a pluvial Lake, also known as shallow Lake, located on the south-east of Iran and adjacent to Afghanistan, and Pakistan borders is investigated. The Lake is the main source of resources (agriculture, fishing and hunting) for the people around it and politically important in the region since it is shared among three different countries. The purpose of the research is to find the Lake's area from 1972 to 2015 and to see if any drought or water resources management has affected the lake. Analyzing satellites imagery from Landsat shows that the area of the Lake changes seasonally and intra-annually. Significant seasonal effects are found in 1975,1977, 1987, 1993, 1996, 1998, 2000, 2009 and 2011, as well as, substantial amount of shallow water is found throughout the years. The precipitation records as well as drought historical records are studied for the lake's basin. Meteorological studies suggest that the drought, decrease of rainfalls in the province and the improper management of the Lake have caused environmental, economic and geographical consequences. The results reveal that lake has experienced at least two prolong dryings since 1972 which drought cannot solely be blamed as main forcing factor.Proper lakes function can ease the impact of floods and drought especially in arid and semi-arid regions. They are important environmentally and can directly affect human lives. Better understanding of the effect of climate change and human-driven changes on lakes

  7. Environmental Assessment: Gulf Power Company Military Point Transmission Line Project

    Science.gov (United States)

    2014-05-12

    1500.4. 1.4. 1 Geology No geological hazards, seismic risks, or unstable slopes occur in the vicinity of Military Point on Tyndall AFB. Therefore, the...with sand grout to fill any voids within the casing and provide thermal insulation for the electric cable. Lengths greater than 3,000 feet would be...devices designed to either insulate or isolate potential contact points have. been recommended to minimize the risk of eagle electrocution, which are

  8. Least tern and piping plover nesting at sand pits in Nebraska

    Science.gov (United States)

    Sidle, John G.; Kirsch, E.M.

    1993-01-01

    Endangered Least Terns (Sterna antillarum) and threatened Piping Plovers (Charadrius melodus) nest at commercial sand and gravel mining operations (sand pits) along the Platte River system in Nebraska. Sandbar habitat has been disappearing since the early 1900's along the Platte River system, but numbers of sand pits have increased. We hypothesized that birds would more fully utilize sand pits where suitable sandbar habitat was limited. We inventoried sand pits and censused terns and plovers on both habitats along the Loup River, part of the North Loup River, and most of the Platte River during 1988-1991. Using aircraft, we also quantified features of suitable sand pits present on the central Platte in 1988 and lower Platte in 1990, and related features to abundance and presence of birds. We found 225 sand pits of which 78 were suitable and 187 were unsuitable for nesting. Along the central Platte, where sandbar habitat is severely degraded, birds nested at 81% of the suitable sand pits (N = 32) at least once during 1988-1991, and most birds (61-94%) nested on sand pits. Along the lower Platte, where both sandbar and sand pit habitat are plentiful, birds nested at 60% of the suitable sand pits (N = 35) at least once during 1988-1991, and most birds (60-86%) nested on sandbars. Numbers of terns and plovers were more weakly correlated with features of sand pits on the central Platte than on the lower Platte. Least Terns and Piping Plovers seem to use more of the suitable sand pit habitat on the central Platte than on the lower Platte. Sand pits probably have influenced the birds' distribution by providing alternative nesting habitat along rivers where suitable sandbars are rare or absent.

  9. Characterization of sand lenses embedded in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Klint, K.E.S.; Nilsson, B.

    2012-01-01

    Tills dominate large parts of the superficial sediments on the Northern hemisphere. These glacial diamictons are extremely heterogeneous and riddled with fractures and lenses of sand or gravel. The frequency and geometry of sand lenses within tills are strongly linked to glaciodynamic processes...

  10. Sand impaction of the small intestine in eight dogs.

    Science.gov (United States)

    Moles, A D; McGhite, A; Schaaf, O R; Read, R

    2010-01-01

    To describe signalment, clinical findings, imaging and treatment of intestinal sand impaction in the dog. Medical records of dogs with radiographic evidence of small intestinal sand impaction were reviewed. Sand impaction resulting in small intestinal obstruction was diagnosed in eight dogs. All dogs presented with signs of vomiting. Other clinical signs included anorexia, lethargy and abdominal pain. Radiographs confirmed the presence of radio-opaque material consistent with sand causing distension of the terminal small intestine in all dogs. Four dogs were treated surgically for their impaction and four dogs were managed medically. Seven of the eight dogs survived. Both medical and surgical management of intestinal sand impaction in the dog can be effective and both afford a good prognosis for recovery.

  11. On the Salt Water Intrusion into the Durusu Lake, Istanbul: A Joint Central Loop TEM And Multi-Electrode ERT Field Survey

    Science.gov (United States)

    Ardali, Ayça Sultan; Tezkan, Bülent; Gürer, Aysan

    2018-02-01

    Durusu Lake is the biggest and most important freshwater source supplying drinking water to the European side of Istanbul. In this study, electrical resistivity tomography (ERT) and transient electromagnetic (TEM) measurements were applied to detect a possible salt water intrusion into the lake and to delineate the subsurface structure in the north of Durusu Lake. The ERT and TEM measurements were carried out along six parallel profiles extending from the sea coast to the lake shore on the dune barrier. TEM data were interpreted using different 1-D inversion methods such as Occam, Marquardt, and laterally constrained inversion (LCI). ERT data were interpreted using 2-D inversion techniques. The inversion results of ERT and TEM data were shown as resistivity depth sections including topography. The sand layer spreading over the basin has a resistivity of 150-400 Ωm with a thickness of 5-10 m. The sandy layer with clay, silt, and gravel has a resistivity of 15-100 Ωm and a thickness of 10-40 m followed by a clay layer of a resistivity below 10 Ωm. When the inversion of these data is interpreted along with the hydrogeology of the area, it is concluded that the salt water intrusion along the dune barrier is not common and occurs at a particular area where the distance between lake and sea is very close. Using information from boreholes around the lake, it was verified that the common conductive region at depths of 30 m or more consists of clay layers and clay lenses.

  12. Consolidation of the formation sand by chemical methods

    Directory of Open Access Journals (Sweden)

    Mariana Mihočová

    2006-10-01

    Full Text Available The sand control by consolidation involves the process of injecting chemicals into the naturally unconsolidated formation to provide an in situ grain-to-grain cementation. The sand consolidation chemicals are available for some 30 years. Several types of consolidating material were tried. Presently available systems utilize solidified plastics to provide the cementation. These systems include phenol resin, phenol-formaldehyde, epoxy, furan and phenolic-furfuryl.The sand consolidation with the steam injection is a novel technique. This process provides a highly alkaline liquid phase and temperatures to 300 °C to geochemically create cements by interacting with the dirty sand.While the formation consolidation has widely applied, our experience has proved a high level of success.

  13. Reuse of waste foundry sand through interaction with sodium silicate binder

    International Nuclear Information System (INIS)

    Souza, J.C.; Chinelatto, A.S.A.; Chinelatto, A.L.; Oliveira, I.L.

    2012-01-01

    Green sand molds are used in metal casting process. However, after heating, activated bentonite present in green sand lose the binding properties, and part of the foundry sand has to be discarded from the process. The ABNT NBR 15.984/2011 establishes the management of waste foundry sand (WFS) avoiding disposal in landfills. The objective of this work was to investigate the possibility of reusing the WFS from the study of their interaction with sodium silicate binder. Studies with silica sand and new green sand was performed to compare the results obtained with the WFS. The characterizations of the samples were performed by measures the compressive strength, X-ray diffraction, optical microscopy and scanning electron microscopy. The results showed that there is interaction of the sodium silicate with the WFS as well as with the silica sand and green sand. (author)

  14. Geotechnical properties of crude oil contaminated sand

    International Nuclear Information System (INIS)

    Puri, V.K.; Das, B.M.; Cook, E.E.; Shin, E.C.

    1994-01-01

    Contamination of soil due to an oil spill influences its subsequent engineering behavior. An investigation was conducted to study the effect of crude oil contamination on compaction characteristics, shear strength, one-dimensional compression, and coefficient of permeability. Water permeability was also determined by using commercial grade motor oils as contaminants. The test results indicate that the compaction characteristics are influenced by oil contamination. The angle of internal friction of sand (based on total stress condition) decreases due to presence of oil within the pore spaces in sand. One dimensional compression characteristics of sand are significantly influenced by oil contamination resulting in a decrease in the value of constrained modulus with increase in the degree of oil contamination compared to the case of dry sand. Water permeability was observed to be a function of the initial viscosity and the degree of saturation due to the contaminating oil

  15. Spatiotemporal patterns of mercury accumulation in lake sediments of western North America

    Science.gov (United States)

    Drevnick, Paul; Cooke, Colin A.; Barraza, Daniella; Blais, Jules M.; Coale, Kenneth; Cumming, Brian F.; Curtis, Chris; Das, Biplob; Donahue, William F.; Eagles-Smith, Collin A.; Engstrom, Daniel R.; Fitzgerald, William F.; Furl, Chad V.; Gray, John R.; Hall, Roland I.; Jackson, Togwell A.; Laird, Kathleen R.; Lockhart, W. Lyle; Macdonald, Robie W.; Mast, M. Alisa; Mathieu, Callie; Muir, Derek C.G.; Outridge, Peter; Reinemann, Scott; Rothenberg, Sarah E.; Ruiz-Fernandex, Ana Carolina; St. Louis, V.L.; Sanders, Rhea; Sanei, Hamed; Skierszkan, Elliott; Van Metre, Peter C.; Veverica, Timothy; Wiklund, Johan A.; Wolfe, Brent B.

    2016-01-01

    For the Western North America Mercury Synthesis, we compiled mercury records from 165 dated sediment cores from 138 natural lakes across western North America. Lake sediments are accepted as faithful recorders of historical mercury accumulation rates, and regional and sub-regional temporal and spatial trends were analyzed with descriptive and inferential statistics. Mercury accumulation rates in sediments have increased, on average, four times (4×) from 1850 to 2000 and continue to increase by approximately 0.2 μg/m2 per year. Lakes with the greatest increases were influenced by the Flin Flon smelter, followed by lakes directly affected by mining and wastewater discharges. Of lakes not directly affected by point sources, there is a clear separation in mercury accumulation rates between lakes with no/little watershed development and lakes with extensive watershed development for agricultural and/or residential purposes. Lakes in the latter group exhibited a sharp increase in mercury accumulation rates with human settlement, stabilizing after 1950 at five times (5×) 1850 rates. Mercury accumulation rates in lakes with no/little watershed development were controlled primarily by relative watershed size prior to 1850, and since have exhibited modest increases (in absolute terms and compared to that described above) associated with (regional and global) industrialization. A sub-regional analysis highlighted that in the ecoregion Northwestern Forest Mountains, mercury deposited to watersheds is delivered to lakes. Research is warranted to understand whether mountainous watersheds act as permanent sinks for mercury or if export of “legacy” mercury (deposited in years past) will delay recovery when/if emissions reductions are achieved.

  16. Impacts of simulated climate change and fungal symbionts on survival and growth of a foundation species in sand dunes.

    Science.gov (United States)

    Emery, Sarah M; Rudgers, Jennifer A

    2013-12-01

    For many ecosystems, one of the primary avenues of climate impact may be through changes to foundation species, which create habitats and sustain ecosystem services. For plants, microbial symbionts can often act as mutualists under abiotic stress and may mediate foundational plant responses to climate change. We manipulated the presence of endophytes in Ammophila breviligulata, a foundational sand dune species, to evaluate their potential to influence plant responses to climate change. We simulated projected climate change scenarios for temperature and precipitation using a growth chamber experiment. A 5 °C increase in temperature relative to current climate in northern Michigan reduced A. breviligulata survival by 45 %. Root biomass of A. breviligulata, which is critical to dune stabilization, was also strongly reduced by temperature. Plants inoculated with the endophyte had 14 % higher survival than endophyte-free plants. Contrary to our prediction, endophyte symbiosis did not alter the magnitude or direction of the effects of climate manipulations on A. breviligulata survival. However, in the absence of the endophyte, an increase in temperature increased the number of sand grains bound by roots by 80 %, while in symbiotic plants sand adherence did not significantly respond to temperature. Thus, plant-endophyte symbiosis actually negated the benefits in ecosystem function gained under a warmer climate. This study suggests that heat stress related to climate change in the Great Lakes may compromise the ability of A. breviligulata to stabilize dune ecosystems and reduce carbon storage and organic matter build-up in these early-successional systems due to reduced plant survival and root growth.

  17. Assessing trends in fishery resources and lake-water aluminum from paleolimnological analyses of siliceous algae

    International Nuclear Information System (INIS)

    Kingston, J.C.; Birks, H.J.B.; Uutala, A.J.; Cummings, B.F.; Smol, J.P.

    1992-01-01

    Lake water aluminum concentrations have a significant influence on the composition of microfossil assemblages of diatoms and chrysophytes deposited in lake sediments. With the paleolimnological approach of multilake datasets in the Adirondack region of New York, USA, the authors use canonical correspondence analysis to describe past trends in lake water Al. Four lakes, previously investigated regarding acidification and fishery trends, are used to demonstrate that paleolimnological assessment can also provide direction, timing, and magnitude of trends for both toxic metals and fish resources. Additionally, the authors use weighted average regression and calibration to obtain quantitative reconstructions of past lake water Al concentrations. Such reconstructions provide further insight into fishery resource damage and can be compared with modelling results. According to paleolimnological reconstructions, some of the naturally most acidic lakes in the Adirondack region had preindustrial lake water concentrations of inorganic monomeric Al near 4/micromol times L. Although these high concentrations are surprising from a geochemical point of view, they may partially explain the preindustrial absence of fish, as has been independently determined by paleolimnological analysis of phantom midges (Chaoborus). Fishery resource deterioration in acidified Adirondack lakes was coincident with major increases in lake water Al concentrations

  18. [Preliminary Study of Lonicera hypoglauca on Germination Conditions of Sand Culture Seeds and Sterilization Method of Sand Culture Seedling Sterilization].

    Science.gov (United States)

    Tan, Mu-xiu; Zeng, Wen-wen; Wei, Peng-xiao; Mo, Qiao-cheng; Pu, Zu-ning; Cen, Xiu-fen; Shi, Feng-hua

    2015-05-01

    To explore the germination conditions of Lonicera hypoglauca sand culture seeds and the effects of sand culture seedlings sterilization. 0.1% HgCl2 with different sterilization time, different illumination time and temperature culture condition were adopted to study the germination conditions of sand culture seeds. Different sterilization treatments and different hardening-seedling days were used to test the sterilization effect of sand culture seedlings. The sterilization effect of the combination of 75% ethanol 30 s + 0.1% HgCl2 5 min on Lonicera hypoglauca seeds was the optimum,with the average pollution rate of 15.56%, and the average germination rate reached 51.11%. The combination of varied temperature-room temperature under light for 12 h/d was the best, with the average germination rate peaked at 75.49%, and the average germination potential reached 68.36%. The treatment of detergent liquor scrub-tap water wash on the part above the hypocotyl, which was sand cultured under the opening condition and had no root, showed the best sterilization effect, with the average pollution rate was zero, and the average survival rate peaked at 100.00%. The sterilization effect of sand culture seedlings, which was disinfected after cleaning by detergent liquor scrub-tap water wash after hardening-seeding for 30 days, was the best, with the average pollution rate of 50.00%, and the average survival rate of 100.00%. The best sterilization effect is the combination of 75% ethanol 30 s + 0.1% HgCl2 5 min; Lighting for 12 h/d of varied temperature-room temperature is regarded as the optimum culture condition. The treatment of detergent liquor scrub-tap water wash treatment on the part above the hypocotyl,which is sand cultured under the opening condition and had no root, shows the best sterilization effect. For the sand culture seedlings, before inoculated in subculture medium, should be hardening-seedling for some days and sterilized after detergent liquor scrub-tap water wash.

  19. Remote sensing appraisal of Lake Chad shrinkage connotes severe impacts on green economics and socio-economics of the catchment area.

    Science.gov (United States)

    Onamuti, Olapeju Y; Okogbue, Emmanuel C; Orimoloye, Israel R

    2017-11-01

    Lake Chad commonly serves as a major hub of fertile economic activities for the border communities and contributes immensely to the national growth of all the countries that form its boundaries. However, incessant and multi-decadal drying via climate change pose greater threats to this transnational water resource, and adverse effects on ecological sustainability and socio-economic status of the catchment area. Therefore, this study assessed the extent of shrinkage of Lake Chad using remote sensing. Landsat imageries of the lake and its surroundings between 1987 and 2005 were retrieved from Global Land Cover Facility website and analysed using Integrated Land and Water Information System version 3.3 (ILWIS 3.3). Supervised classification of area around the lake was performed into various land use/land cover classes, and the shrunk part of its environs was assessed based on the land cover changes. The shrinkage trend within the study period was also analysed. The lake water size reduced from 1339.018 to 130.686 km 2 (4.08-3.39%) in 1987-2005. The supervised classification of the Landsat imageries revealed an increase in portion of the lake covered by bare ground and sandy soil within the reference years (13 490.8-17 503.10 km 2 ) with 4.98% total range of increase. The lake portion intersected with vegetated ground and soil also reduced within the period (11 046.44-10 078.82 km 2 ) with 5.40% (967.62 km 2 ) total decrease. The shrunk part of the lake covered singly with vegetation increased by 2.74% from 1987 to 2005. The shrunk part of the lake reduced to sand and turbid water showed 5.62% total decrease from 1987 to 2005 and a total decrease of 1805.942 km 2 in area. The study disclosed an appalling rate of shrinkage and damaging influences on the hydrologic potential, eco-sustainability and socio-economics of the drainage area as revealed using ILWIS 3.3.

  20. Strength and Compaction Analysis of Sand-Bentonite-Coal Ash Mixes

    Science.gov (United States)

    Sobti, Jaskiran; Singh, Sanjay Kumar

    2017-08-01

    This paper deals with the strength and compaction characteristics of sand-bentonite-coal ash mixes prepared by varying percentages of sand, bentonite and coal ash to be used in cutoff walls and as a liner or cover material in landfills. The maximum dry density (MDD) and optimum moisture content (OMC) of sand-bentonite mixes and sand-bentonite-coal ash mixes were determined by conducting the standard proctor test. Also, the strength and stiffness characteristics of soil mixes were furnished using unconfined compressive strength test. The results of the study reveal influence of varying percentages of coal ash and bentonite on the compaction characteristics of the sand-bentonite-coal ash mixes. Also, validation of a statistical analysis of the correlations between maximum dry density (MDD), optimum moisture content (OMC) and Specific Gravity (G) was done using the experimental results. The experimental results obtained for sand-bentonite, sand-bentonite-ash and coal ash-bentonite mixes very well satisfied the statistical relations between MDD, OMC and G with a maximum error in the estimate of MDD being within ±1 kN/m3. The coefficient of determination (R2) ranged from 0.95 to 0.967 in case of sand-bentonite-ash mixes. However, for sand-bentonite mixes, the R2 values are low and varied from 0.48 to 0.56.