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Sample records for reservoir sand sedimentation

  1. Sediment management for reservoir

    International Nuclear Information System (INIS)

    Rahman, A.

    2005-01-01

    All natural lakes and reservoirs whether on rivers, tributaries or off channel storages are doomed to be sited up. Pakistan has two major reservoirs of Tarbela and Managla and shallow lake created by Chashma Barrage. Tarbela and Mangla Lakes are losing their capacities ever since first impounding, Tarbela since 1974 and Mangla since 1967. Tarbela Reservoir receives average annual flow of about 62 MAF and sediment deposits of 0.11 MAF whereas Mangla gets about 23 MAF of average annual flows and is losing its storage at the rate of average 34,000 MAF annually. The loss of storage is a great concern and studies for Tarbela were carried out by TAMS and Wallingford to sustain its capacity whereas no study has been done for Mangla as yet except as part of study for Raised Mangla, which is only desk work. Delta of Tarbala reservoir has advanced to about 6.59 miles (Pivot Point) from power intakes. In case of liquefaction of delta by tremor as low as 0.12g peak ground acceleration the power tunnels I, 2 and 3 will be blocked. Minimum Pool of reservoir is being raised so as to check the advance of delta. Mangla delta will follow the trend of Tarbela. Tarbela has vast amount of data as reservoir is surveyed every year, whereas Mangla Reservoir survey was done at five-year interval, which has now been proposed .to be reduced to three-year interval. In addition suspended sediment sampling of inflow streams is being done by Surface Water Hydrology Project of WAPDA as also some bed load sampling. The problem of Chasma Reservoir has also been highlighted, as it is being indiscriminately being filled up and drawdown several times a year without regard to its reaction to this treatment. The Sediment Management of these reservoirs is essential and the paper discusses pros and cons of various alternatives. (author)

  2. Reservoir sedimentation; a literature survey

    NARCIS (Netherlands)

    Sloff, C.J.

    1991-01-01

    A survey of literature is made on reservoir sedimentation, one of the most threatening processes for world-wide reservoir performance. The sedimentation processes, their impacts, and their controlling factors are assessed from a hydraulic engineering point of view with special emphasis on

  3. Estimating Western U.S. Reservoir Sedimentation

    Science.gov (United States)

    Bensching, L.; Livneh, B.; Greimann, B. P.

    2017-12-01

    Reservoir sedimentation is a long-term problem for water management across the Western U.S. Observations of sedimentation are limited to reservoir surveys that are costly and infrequent, with many reservoirs having only two or fewer surveys. This work aims to apply a recently developed ensemble of sediment algorithms to estimate reservoir sedimentation over several western U.S. reservoirs. The sediment algorithms include empirical, conceptual, stochastic, and processes based approaches and are coupled with a hydrologic modeling framework. Preliminary results showed that the more complex and processed based algorithms performed better in predicting high sediment flux values and in a basin transferability experiment. However, more testing and validation is required to confirm sediment model skill. This work is carried out in partnership with the Bureau of Reclamation with the goal of evaluating the viability of reservoir sediment yield prediction across the western U.S. using a multi-algorithm approach. Simulations of streamflow and sediment fluxes are validated against observed discharges, as well as a Reservoir Sedimentation Information database that is being developed by the US Army Corps of Engineers. Specific goals of this research include (i) quantifying whether inter-algorithm differences consistently capture observational variability; (ii) identifying whether certain categories of models consistently produce the best results, (iii) assessing the expected sedimentation life-span of several western U.S. reservoirs through long-term simulations.

  4. Sediment problems in reservoirs. Control of sediment deposits

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, Tom

    1997-12-31

    When a reservoir is formed on a river, sediment will deposit in the reservoir. Such processes are unfortunate, for instance, for the implementation of hydroelectric energy. This thesis studies the problem of reservoir sedimentation and discusses methods of removing the sediments. Various aspects of reservoir sedimentation are discussed. Anthropogenic impacts seem to greatly affect the erosion processes. Temporal distribution is uneven, mainly because of the very large flood events. A world map showing the Reservoir Capacity: Annual Sediment Inflow ratio for reservoirs with volume equal to 10% of annual inflow has been prepared. The map shows that sedimentation is severe in the western parts of North and South America, eastern, southern and northern Africa, parts of Australia and most of Asia. The development of medium-sized reservoirs is difficult, as they are too large for conventional flushing technique and too small to store the sediment that accumulates during their economic lifetime. A computer model, SSIIM, was used with good results in a case study of two flood drawdown trials in Lake Roxburg, New Zealand. Two techniques have been developed that permits controlled suction of sediment and water into a pipe: the Slotted Pipe Sediment Sluicer (SPSS) and the Saxophone Sediment Sluicer (SSS). The techniques exploit the inflow pattern in through a slot in a pipe. An equation describing this inflow pattern was derived and verified experimentally. The SPSS is fixed near the reservoir bed, and sediment that deposits on top of it is removed in the sluicing process. The SSS sluices sediment from the surface of the sediment deposits. Some technical and economic conditions affecting the economics of sediment removal from reservoirs have been identified and studied. 79 refs., 112 figs., 14 tabs.

  5. Effects of oil sands sediments on fish

    International Nuclear Information System (INIS)

    Parrott, J.; Colavecchia, M.; Hewitt, L.; Sherry, J.; Headley, J.; Turcotte, D.; Liber, K.

    2010-01-01

    This paper described a collaborative project organized by Natural Resources Canada (NRCan) Panel of Energy Research and Development (PERD) with researchers from Environment Canada and the University of Saskatchewan. The 4-year study was conducted to assess the toxicity of oil sands sediments and river waters, and reclamation ponds and sediments on laboratory-raised fish. Three sediments from rivers were evaluated for their potential to cause adverse impacts on fathead minnow eggs and larvae for a period of 18 days. The study monitored hatching, larval survival, development, and growth. Naphthenic acids (NA), polycyclic aromatic hydrocarbons (PAHs) and metals were measured in the sediments to determine if the compounds can be correlated with observed toxicity. The study will also assess walleye eggs exposed to sediments, and in situ fish exposures. Toxicity identification and evaluation (TIE) studies will be conducted to isolate the fractions that may affect fish development and growth.

  6. Longshore sediment transport at Golden Sands (Bulgaria

    Directory of Open Access Journals (Sweden)

    Hristo Nikolov

    2006-09-01

    Full Text Available The paper presents the results of studies on the qualitative and quantitative features of the littoral drift at Golden Sands (Bulgaria, carried out jointly by Polish and Bulgarian researchers. The mathematical modelling of physical coastal processes took wave transformation (wave diffraction and refraction; the effects of shoaling and wave breaking and longshore sediment transport into account. The computations were carried out for the mean statistical annual wave climate, determined on the basis of IO BAS wave data, simulated using the WAM method from long-term Black Sea wind data. The results of sediment transport computations clearly show that its direction off the Golden Sands shore is from north to south.

  7. Analysis of Sedimentation in Wonogiri Reservoir

    Directory of Open Access Journals (Sweden)

    Tri Joko Inti Budi Santosa

    2016-01-01

    Full Text Available The Wonogiri reservoir which has 730 million cubic meters of total storage, 90 square kilometers of water area, and 1260 square kilometers of catchment area, is located in the Wonogiri Regency, Central Java Province. It was first established in 1981 and began its operation in 1982 with the expectation that it would last for about 100 years. Today (2002 the reservoir has got a serious problem of sedimentation. The sedimentation is so large that it would decrease the capacity storage of the reservoir and would shorten the length of operation. Therefore, it is necessary to predict the sediment that comes into the reservoir. This research would be based on the total sediment calculation of the sedimentation, through some methods, such as echo sounding measured data, land erosion (USLE, the calculation of the sediment in rivers. This research calculates the sediment capacities based on the water flow data and the sediment rating curves in rivers of Keduang, Tirtomoyo, Temon, upstream reach of Bengawan Solo, Alang, and Wuryantoro. The suspended load was calculated based on the sediment rating curves, whereas the bed load was computed as the percentage of the suspended load. The sum of both calculation results would be the total sediment. The calculation result showed that the total sediment which has come into the reservoir is 6.68 million cubic meters per year. As a comparison, the writer noted that the former researcher using echo sounding method done by the Faculty of Geography of the Universitas Gadjah Mada in 1985, it found that the total sediment capacity which came into the reservoir was 6.60 million cubic meters per year or 5.40 mm per year of sheet erosion. The other research using echo sounding method done by JICA in 2000 found that the total sediment which had come into the reservoir was 4.50 million cubic meters per year or 3.50 mm per year of sheet erosion. By knowing the results of calculation of the total sediment, we can learn that

  8. Analysis of Fluvial Sediment Discharges into Kubanni Reservoir ...

    African Journals Online (AJOL)

    The sediment discharges into the Kubanni Reservoir (KR) has been measured and analysed in this study. The predominant sandy-clay sediment in the reservoir has an estimated total sediment load of 20,387,000 kg/year. The depth and area coverage of the reservoir was surveyed using a defined distributed grid line ...

  9. Stabilization of bottom sediments from Rzeszowski Reservoir

    Directory of Open Access Journals (Sweden)

    Koś Karolina

    2015-06-01

    Full Text Available The paper presents results of stabilization of bottom sediments from Rzeszowski Reservoir. Based on the geotechnical characteristics of the tested sediments it was stated they do not fulfill all the criteria set for soils in earth embankments. Therefore, an attempt to improve their parameters was made by using two additives – cement and lime. An unconfined compressive strength, shear strength, bearing ratio and pH reaction were determined on samples after different time of curing. Based on the carried out tests it was stated that the obtained values of unconfined compressive strength of sediments stabilized with cement were relatively low and they did not fulfill the requirements set by the Polish standard, which concerns materials in road engineering. In case of lime stabilization it was stated that the tested sediments with 6% addition of the additive can be used for the bottom layers of the improved road base.

  10. Reservoir Sedimentation: Impact, Extent, and Mitigation

    Science.gov (United States)

    Hadley, Richard F.

    Storage reservoirs play an important role in water resources development throughout the world. The one problem with reservoirs that is universal is the continual reduction in usable capacity caused by siltation. This book reviews the world picture of erosion and sediment yield, the large variations that exist, and the physical phenomena related to reservoir siltation. The book is in the Technical Paper series of The World Bank (Technical Paper 71) and is not a formal publication. Rather, it is intended to be circulated to encourage discussion and comment and to communicate results quickly. The book is reproduced from typescript, but this does not detract from the value of the contents as a useful text for hydrologrsts, engineers, and soil conservationists in developing countries.

  11. State of the art of reservoir sedimentation management in Spain

    OpenAIRE

    Avendaño Salas, Cándido; Sanz Montero, Esther; Cobo Rayán, Rafael

    2000-01-01

    Part of the total reservoir storage capacity in Spain (56 km3) is lost due to sedimentation processes taking place. Surveys carried out in 121 reservoirs indicate that 6% of them have undergone a capacity reduction of over 50%. However, most of them (81%) are characterised by a reservoir capacity loss below 20%. The most frequent methods used to control reservoir sedimentation in Spain fall into one of the following groups: reduction of sediment yield through basin management and removal of t...

  12. Climate variability and sedimentation of a hydropower reservoir

    International Nuclear Information System (INIS)

    Riedel, M.

    2008-01-01

    As part of the relicensing of a large Hydroelectric Project in the central Appalachians, large scale watershed and reservoir sedimentation models were developed to forecast potential sedimentation scenarios. The GIS based watershed model was spatially explicit and calibrated to long term observed data. Potential socio/economic development scenarios were used to construct future watershed land cover scenarios. Climatic variability and potential change analysis were used to identify future climate regimes and shifts in precipitation and temperature patterns. Permutations of these development and climate changes were forecasted over 50 years and used to develop sediment yield regimes to the project reservoir. Extensive field work and reservoir survey, including current and wave instrumentation, were used to characterize the project watershed, rivers and reservoir hydrodynamics. A fully 3 dimensional hydrodynamic reservoir sedimentation model was developed for the project and calibrated to observed data. Hydrologic and sedimentation results from watershed forecasting provided boundary conditions for reservoir inputs. The calibrated reservoir model was then used to forecast changes in reservoir sedimentation and storage capacity under different future climate scenarios. Results indicated unique zones of advancing sediment deltas and temporary storage areas. Forecasted changes in reservoir bathymetry and sedimentation patterns were also developed for the various climate change scenarios. The warmer and wetter scenario produced sedimentation impacts similar to extensive development under no climate change. The results of these analyses are being used to develop collaborative watershed and soil conservation partnerships to reduce future soil losses and reservoir sedimentation from projected development. (author)

  13. Mrica Reservoir Sedimentation: Current Situation and Future Necessary Management

    Directory of Open Access Journals (Sweden)

    Puji Utomo

    2017-09-01

    Full Text Available Mrica Reservoir is one of many reservoirs located in Central Java that experienced a considerably high sedimentation during the last ten years. This condition has caused a rapid decrease in reservoir capacity. Various countermeasures have been introduced to reduce the rate of the reservoir sedimentation through catchment management and reservoir operation by means of flushing and/or dredging. However, the sedimentation remains intensive so that the fulfillment of water demand for electrical power generation was seriously affected. This paper presents the results of evaluation on the dynamics of the purpose of this research is to evaluate the sediment balance of the Mrica Reservoir based on two different scenarios, i.e. the existing condition and another certain type of reservoir management. The study on sediment balance was carried out by estimating the sediment inflow applying sheet erosion method in combination with the analysis of sediment rating curve. The measurement of the deposited sediment rate in the reservoir was conducted through the periodic echo sounding, whereas identification of the number of sediment that has been released from the reservoir was carried out through the observation on both flushing and dredging activities. The results show that during the last decade, the rate of the sediment inflow was approximately 5.869 MCM/year, whereas the released sediment from the reservoir was 4.097 MCM/year. In order to maintain the reservoir capacity, therefore, at least 1.772 MCM/year should be released from the reservoir by means of either flushing or dredging. Sedimentation management may prolong the reservoir’s service life to exceed the design life. Without sediment management, the lifetime of the reservoir would have finished by 2016, whereas with the proper management the lifetime may be extended to 2025.

  14. Analysis of Fluvial Sediment Discharges into Kubanni Reservoir ...

    African Journals Online (AJOL)

    User

    The predominant sandy-clay sediment in the reservoir has an estimated total sediment load ... NIGERIAN JOURNAL OF TECHNOLOGY, VOL. 29 NO 2, JUNE ... the upper limit of application is 1-5gl !1 ... Laursen, Modified Einstein Procedure,.

  15. FEASIBILITY STUDY OF SEDIMENT FLUSHING FROM MOSUL RESERVOIR, IRAQ

    Directory of Open Access Journals (Sweden)

    Thair Mahmood Al-Taiee

    2015-02-01

    Full Text Available The Feasibility of sediment flushing  from Mosul reservoir located northern iraq was conducted. Many up to date world criteria and indices for checking the efficiency of sediment flushing from reservoir which have been got through analyzing large amount of  data from many flushed reservoirs  in the world which were depended tested and applied in the present case study (Mosul Reservoir. These criteria and indices depend mainly on the hydrological , hydraulic and  topographical properties of the reservoirs in-addition to the operation plan of the reservoirs. They gave a good indication for checking the efficiency of the sediment flushing  process in the reservoirs. It was concluded that approximately the main criteria for the successful flushing sediment was  verified  in  Mosul  reservoir  such as  Sediment Balance Ratio   (SBR and the Long Term Capacity Ratio (LTCR,the shape factor  of reservoir (W/L and the hydraulic condition such as the percentage of (Qf/Qin and (Vf/Vin. This gave an indication that the processes of flushing sediment in Mosul reservoir is probably feasible and may be applied  in the future to maintain the water storage in the reservoir.

  16. Athabasca tar sand reservoir properties derived from cores and logs

    International Nuclear Information System (INIS)

    Woodhouse, R.

    1976-01-01

    Log interpretation parameters for the Athabasca Tar Sand Lease No. 24 have been determined by careful correlation with Dean and Stark core analysis data. Significant expansion of Athabasca cores occurs as overburden pressure is removed. In the more shaly sands the core analysis procedures remove adsorbed water from the clays leading to further overestimation of porosity and free water volume. Log interpretation parameters (R/sub w/ = 0.5 ohm . m and m = n = 1.5) were defined by correlation with the weight of tar as a fraction of the weight of rock solids (grain or dry weight fraction of tar). This quantity is independent of the water content of the cores, whereas porosity and the weight of tar as a fraction of the bulk weight of fluids plus solids (bulk weight fraction) are both dependent on water content. Charts are provided for the conversion of bulk weight fraction of fluids to porosity; grain weight fraction of fluids to porosity; log derived porosity and core grain weight tar to water saturation. Example results show that the core analysis grain weight fraction of tar is adequately matched by the log analyses. The log results provide a better representation of the reservoir fluid volumes than the core analysis data

  17. 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.

  18. Sediment volume in the north polar sand seas of Mars

    International Nuclear Information System (INIS)

    Lancaster, N.; Greeley, R.

    1990-01-01

    Data from studies of the cross-sectional area of terrestrial transverse dunes have been combined with maps of dune morphometry derived from Viking orbiter images to generate new estimates of sediment thickness and dune sediment volume in the north polar sand seas of Mars. A relationship between dune spacing and equivalent sediment thickness (EST) was developed from field data on Namibian and North American dunes and was applied to data on dune spacing and dune cover measured on Viking orbiter images to generate maps of dune sediment thickness for Martian north polar sand seas. There are four major sand seas in the north polar region of Mars, covering an area of 6.8 x 10 5 km 2 . Equivalent sediment thickness ranges between 0.5 and 6.1 m with a mean of 1.8 m. The sand seas contain a total of 1158 km 3 of dune sediment, which may have been derived by erosion of polar layered deposits and concentrated in its present location by winds that change direction seasonally

  19. Simulation of Reservoir Sediment Flushing of the Three Gorges Reservoir Using an Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Xueying Li

    2016-05-01

    Full Text Available Reservoir sedimentation and its effect on the environment are the most serious world-wide problems in water resources development and utilization today. As one of the largest water conservancy projects, the Three Gorges Reservoir (TGR has been controversial since its demonstration period, and sedimentation is the major concern. Due to the complex physical mechanisms of water and sediment transport, this study adopts the Error Back Propagation Training Artificial Neural Network (BP-ANN to analyze the relationship between the sediment flushing efficiency of the TGR and its influencing factors. The factors are determined by the analysis on 1D unsteady flow and sediment mathematical model, mainly including reservoir inflow, incoming sediment concentration, reservoir water level, and reservoir release. Considering the distinguishing features of reservoir sediment delivery in different seasons, the monthly average data from 2003, when the TGR was put into operation, to 2011 are used to train, validate, and test the BP-ANN model. The results indicate that, although the sample space is quite limited, the whole sediment delivery process can be schematized by the established BP-ANN model, which can be used to help sediment flushing and thus decrease the reservoir sedimentation.

  20. Physical Model-Based Investigation of Reservoir Sedimentation Processes

    Directory of Open Access Journals (Sweden)

    Cheng-Chia Huang

    2018-03-01

    Full Text Available Sedimentation is a serious problem in the operations of reservoirs. In Taiwan, the situation became worse after the Chi-Chi Earthquake recorded on 21 September 1999. The sediment trap efficiency in several regional reservoirs has been sharply increased, adversely affecting the operations on water supplies. According to the field record, the average annual sediment deposition observed in several regional reservoirs in Taiwan has been increased. For instance, the typhoon event recorded in 2008 at the Wushe Reservoir, Taiwan, produced a 3 m sediment deposit upstream of the dam. The remaining storage capacity in the Wushe Reservoir was reduced to 35.9% or a volume of 53.79 million m3 for flood water detention in 2010. It is urgent that research should be conducted to understand the sediment movement in the Wushe Reservoir. In this study, a scale physical model was built to reproduce the flood flow through the reservoir, investigate the long-term depositional pattern, and evaluate sediment trap efficiency. This allows us to estimate the residual life of the reservoir by proposing a modification of Brune’s method. It can be presented to predict the lifespan of Taiwan reservoirs due to higher applicability in both the physical model and the observed data.

  1. Evaluation of an Empirical Reservoir Shape Function to Define Sediment Distributions in Small Reservoirs

    Directory of Open Access Journals (Sweden)

    Bogusław Michalec

    2015-08-01

    Full Text Available Understanding and defining the spatial distribution of sediment deposited in reservoirs is essential not only at the design stage but also during the operation. The majority of research concerns the distribution of sediment deposition in medium and large water reservoirs. Most empirical methods do not provide satisfactory results when applied to the determination of sediment deposition in small reservoirs. Small reservoir’s volumes do not exceed 5 × 106 m3 and their capacity-inflow ratio is less than 10%. Long-term silting measurements of three small reservoirs were used to evaluate the method described by Rahmanian and Banihashemi for predicting sediment distributions in small reservoirs. Rahmanian and Banihashemi stated that their model of distribution of sediment deposition in water reservoir works well for a long duration operation. In the presented study, the silting rate was used in order to determine the long duration operation. Silting rate is a quotient of volume of the sediment deposited in the reservoir and its original volume. It was stated that when the silting rate had reached 50%, the sediment deposition in the reservoir may be described by an empirical reservoir depth shape function (RDSF.

  2. Selenium in Reservoir Sediment from the Republican River Basin

    Science.gov (United States)

    Juracek, Kyle E.; Ziegler, Andrew C.

    1998-01-01

    Reservoir sediment quality is an important environmental concern because sediment may act as both a sink and a source of water-quality constituents to the overlying water column and biota. Once in the food chain, sediment-derived constituents may pose an even greater concern due to bioaccumulation. An analysis of reservoir bottom sediment can provide historical information on sediment deposition as well as magnitudes and trends in constituents that may be related to changes in human activity in the basin. The assessment described in this fact sheet was initiated in 1997 by the U.S. Geological Survey (USGS), in cooperation with the Bureau of Reclamation (BOR), U.S. Department of the Interior, to determine if irrigation activities have affected selenium concentrations in reservoir sediment of the Republican River Basin of Colorado, Kansas, and Nebraska.

  3. Historical record of mercury contamination in sediments from the Babeni Reservoir in the Olt River, Romania.

    Science.gov (United States)

    Bravo, Andrea Garcia; Loizeau, Jean-Luc; Ancey, Lydie; Ungureanu, Viorel Gheorghe; Dominik, Janusz

    2009-08-01

    -alkali industry. Two strong peaks could be distinguished in older sediments. The mean rate of sedimentation (5.9 cm/year) was calculated from the depth of the (137)Cs Chernobyl peak. This was in good agreement with the sedimentation rate estimated at this site from a bathymetric study. Assuming a constant sedimentation rate, the two Hg peaks would reflect two contamination events in 1987 and 1991, respectively. However, it is also possible that the two peaks belong to the same contamination event in 1987 but were separated by a sediment layer richer in sand and silt. This layer had a low Hg concentration, which can be interpreted as a mass deposition event related to a major flood bringing Hg-free sediments. Whilst the chlor-alkali plant partly switched to a cleaner technology in 1999, no obvious decrease of Hg concentrations was observed in recent decade. Results from the sediment core reflected the historical trend of Hg release from the chlor-alkali plant, revealed important contamination episodes and confirmed a legacy of contamination of Hg in recent sediments even if the concentrations of Hg decreased toward the surface due to a more efficient emission control. Although the Hg concentrations in Babeni Reservoir sediments were extremely high in the late eighties and they remain one order of magnitude higher in the surface sediments than in sediments from the upstream reservoir, little is known about the transfer of Hg to the biota and human population. Our initial measurements indicate the presence of monomethyl-Hg (MMHg) in pore water, but further studies are necessary to evaluate fluxes of MMHg at the sediment-water interface. Samples of fish and hair from various groups of the local population were recently collected to evaluate the potential hazard of Hg contamination to human health in the Rm Valcea region.

  4. Modelling of sedimentation processes inside Roseires Reservoir (Sudan) (abstract)

    NARCIS (Netherlands)

    Ali, Y.S.A.; Omer, A.Y.A.; Crosato, A.

    2013-01-01

    Roseires Reservoir is located on the Blue Nile River, in Sudan (figure 1). It is the first trap to the sediments coming from the upper catchment in Ethiopia, which suffers from high erosion and desertification problems. The reservoir lost already more than one third of its storage capacity due to

  5. Production of Natural Gas and Fluid Flow in Tight Sand Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Maria Cecilia Bravo

    2006-06-30

    This document reports progress of this research effort in identifying relationships and defining dependencies between macroscopic reservoir parameters strongly affected by microscopic flow dynamics and production well performance in tight gas sand reservoirs. These dependencies are investigated by identifying the main transport mechanisms at the pore scale that should affect fluids flow at the reservoir scale. A critical review of commercial reservoir simulators, used to predict tight sand gas reservoir, revealed that many are poor when used to model fluid flow through tight reservoirs. Conventional simulators ignore altogether or model incorrectly certain phenomena such as, Knudsen diffusion, electro-kinetic effects, ordinary diffusion mechanisms and water vaporization. We studied the effect of Knudsen's number in Klinkenberg's equation and evaluated the effect of different flow regimes on Klinkenberg's parameter b. We developed a model capable of explaining the pressure dependence of this parameter that has been experimentally observed, but not explained in the conventional formalisms. We demonstrated the relevance of this, so far ignored effect, in tight sands reservoir modeling. A 2-D numerical simulator based on equations that capture the above mentioned phenomena was developed. Dynamic implications of new equations are comprehensively discussed in our work and their relative contribution to the flow rate is evaluated. We performed several simulation sensitivity studies that evidenced that, in general terms, our formalism should be implemented in order to get more reliable tight sands gas reservoirs' predictions.

  6. 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

  7. Morphological, sediment and soil chemical characteristics of dry tropical shallow reservoirs in the Southern Mexican Highlands

    Directory of Open Access Journals (Sweden)

    José Luis ARREDONDO-FIGUEROA

    2011-02-01

    Full Text Available The morphometry, sediment and soil chemical characteristics of eleven dry tropical shallow reservoirs situated in Southern Mexican Highlands were studied. The reservoirs are located at 1104 to 1183 meters above sea level in a sedimentary area. Seventeen morphometric and eight sediment and soil chemical parameters were measured. The results of the morphometric parameters showed that these reservoirs presented a soft and roughness bottom, with an ellipsoid form and a concave depression that permit the mix up of water and sediments, causing turbidity and broken thermal gradients; their slight slopes allowed the colonization of submerged macrophyte and halophyte plants and improved the incidence of sunlight on water surface increasing evaporation and primary productivity. Dry tropical shallow reservoirs have fluctuations in area, and volume according to the amount of rainfall, the effect of evaporation, temperature, lost volume for irrigation, and other causes. The sand-clay was the most important sediment texture and their values fluctuated with the flooded periods. The concentration-dilution cycle showed a direct relationship in the percentage of organic matter in the soil as well as with pH, soil nitrogen and phosphorus. El Tilzate, El Candelero and El Movil were related by the shore development and high concentrations of organic matter and nitrogen in the soil. Finally, we emphasize the importance of this study, in relation to possible future changes in morphometrical parameters as a consequence of human impact.

  8. Design and modeling of reservoir operation strategies for sediment management

    NARCIS (Netherlands)

    Sloff, C.J.; Omer, A.Y.A.; Heynert, K.V.; Mohamed, Y.A.

    2015-01-01

    Appropriate operation strategies that allow for sediment flushing and sluicing (sediment routing) can reduce rapid storage losses of (hydropower and water-supply) reservoirs. In this study we have shown, using field observations and computational models, that the efficiency of these operations

  9. Simulating cold production by a coupled reservoir-geomechanics model with sand erosion

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.; Xue, S. [Petro-Geotech Inc., Calgary, AB (Canada)

    2002-06-01

    This paper presents a newly developed fully coupled reservoir-geomechanics model with sand erosion. Sand production occurs during aggressive production induced by the impact of viscous fluid flow and the in situ stress concentration near a wellbore, as well as by perforation tips in poorly consolidated formations. This compromises oil production, increases well completion costs, and reduces the life cycles of equipment down hole and on the surface. The proposed model can be used for sand production studies in conventional oil/gas reservoirs such as the North Sea as well as in heavy oil reservoirs such as in northwestern Canada. Instead of generating a high permeability network in reservoirs, the enhanced oil production is determined by the increase in the effective wellbore radius. This paper presents the general model. A detailed study on the capillary pressure and the impact of multiphase flow on sanding and erosion will be conducted at a later date. It appears that 2 phase flow can be important to elastoplasticity if no significant sand erosion has occurred. It was determined that high porosity is induced by erosion and capillary pressure. Two phase flow can be important when the built-up drag force carries sand-fluid slurry into the well. It is concluded that viscosity and flow velocity can help estimate the slurry transport, sand rate and enhanced oil production. 22 refs., 3 tabs., 11 figs.

  10. Avoiding The Inevitable? Capacity Loss From Reservoir Sedimentation

    Science.gov (United States)

    Gray, John R.; Randle, Timothy J.; Collins, Kent L.

    2013-01-01

    The inexorable loss of capacity of the nation's reservoirs—sooner or later threatening water supplies for municipal, agricultural, and industrial uses—is but one of a number of deleterious effects wrought by sediment deposition. Trapped sediments can also damage or bury dam outlets, water intakes, and related infrastructure. Downstream effects of sediment capture and retention by reservoirs can include channel and habitat degradation and biotic alterations.

  11. Movement of Sediment Associated With Lowered Reservoir Levels in the Rio La Venta Arm of the Presa Netzahualcoyotl, Chiapas, Mexico

    Science.gov (United States)

    Hilton, S.; de La Fuente, J.; Lisle, T. E.; Velasquez, J.; Allison, B.; Olson, B.; Quinones, R.

    2003-12-01

    A joint sedimentation study is currently underway at the Netzahualcoyotl reservoir in Chiapas, Mexico, involving the Comision Nacional de Areas Naturales Protegidas (CONANP) of the Secretaria de Medio Ambiente y Recursos Naturales and the USDA Forest Service. The reservoir is adjacent to the Reserva de la Biosfera, Selva El Ocote, administered by CONANP. Ongoing research is intended to provide watershed and reservoir managers with strategies to protect the resources of Rio La Venta canyon. The Rio La Venta arm of the reservoir is incised into karst terrain, with near-vertical limestone walls up to 300 meters high. The canyon is fed by two rivers, Rio La Selva and Rio Negro, and is surrounded by pristine tropical forest. The majority of the clastic sediment (predominantly sand and fine gravel) entering the reservoir originates in the headwaters of the two rivers which are underlain by weathered and dissected granitic terrain. Rapid sedimentation of the partially inundated canyon poses a threat to the aquatic ecosystem, as well as to recreational resources. Longitudinal and transverse profiles were surveyed in the inundated canyon in March of 2002 and repeated in April of 2003 when the reservoir level was 15 meters lower. The 2002 longitudinal profile shows an inflection from a slope of 0.0017 to one of 0.0075 at 7.2 km downstream of the mouth of Rio Negro. In 2003, the two slopes remained the same, but the bed lowered about 5 meters and the inflection point moved downstream about 2.3 km. We calculated that reservoir lowering in 2003 allowed the transport of 2.5 million cubic meters of sand further out into the reservoir. This volume is more than the average annual rate of filling up to the 2002 level since 1984 when sedimentation was not as advanced (De la Fuente et al., 2002), which was calculated disregarding loss of sediment to the main reservoir. Field observations at late dry season low flows in 2003 revealed active transport of sand and pebbles and formation

  12. Evaluation of sediment management strategies on reservoir storage depletion rate: a case study

    NARCIS (Netherlands)

    Ali, M.; Sterk, G.

    2010-01-01

    Sedimentation aspects have a major role during the design of new reservoir projects because life of the reservoir mainly depends upon sediment handling during reservoir operation. Therefore, proper sediment management strategies should be adopted to enhance the life span of reservoirs. Basha

  13. Acoustic characteristics of sand sediment with circular cylindrical pores

    International Nuclear Information System (INIS)

    Roh, Heui-Seol; Lee, Kang-Il; Yoon, Suk-Wang

    2004-01-01

    The acoustic pressure transmission coefficient and the phase velocity are experimentally measured as functions of the frequency and the porosity in sand sediment slabs with circular cylindrical pores filled with water and air. They are also theoretically estimated with the modified Biot-Attenborough (MBA) model, which uses a separate treatment of the viscous and the thermal effects in a non-rigid porous medium with water- and air-filled cylindrical pores. In this study, the fast (first kind) wave and the slow (second kind) wave are not separated in the transmitted signals through a sediment slab without the circular cylindrical pores, but they are separated in the transmitted signals through a sediment slab with pores. Both the phase velocities and the transmission coefficients of the fast wave and the slow wave in the sediment slabs with water- and air-filled cylindrical pores are sensitive to the air and the water porosities. It is proposed that the fast and the slow waves have opposite behaviors for several acoustic characteristics. The generalized tortuosity factor and the dynamic shape factor are introduced from the acoustic characteristics of the fast wave. The experimental results show reasonable agreement with the theoretical results estimated with the MBA model. These results suggest the possibility of predicting the acoustic characteristics of a sediment as functions of arbitrary water and air porosities. This study may also be applicable to understanding acoustic wave propagations in a bubbly liquid sediment for underwater applications and in cancellous bone for the diagnosis of osteoporosis.

  14. Radioactive fallout reconstruction from contemporary measurements of reservoir sediments

    International Nuclear Information System (INIS)

    Krey, P.W.; Heit, M.; Miller, K.M.

    1990-01-01

    The temporal history of atmospheric deposition to a watershed area can be preserved in the sediment of a lake or reservoir that is supplied by the watershed. The 137 Cs and isotopic Pu concentrations with depth were determined in the sediments of two reservoirs, Enterprise and Deer Creek, which are located in widely separated regions of the state of Utah. Our data not only reconstruct the history of the total radioactive fallout in the area, but also permit estimating the contributions from global sources and from the Nevada Test Site detonations in the 1950s

  15. Technical Note: Stability of a Levee Made of Bottom Sediments From a Dam Reservoir

    Directory of Open Access Journals (Sweden)

    Koś Karolina

    2015-02-01

    Full Text Available Stability analysis of a levee made of the bottom sediments from Czorsztyn-Niedzica Reservoir is presented in the paper. These sediments were classified as silty sands and, based on the authors' own research, their geotechnical parameters were beneficial, so the possibility of using this material for the hydraulic embankments was considered. Stability and filtration calculations were carried out for a levee that had the same top width - 3 m, slope inclinations 1:2 and different heights: 4, 6 and 8 m. Two methods were used: analytical and numerical. Calculations were carried out without and with a steady and unsteady seepage filtration. Based on the analysis carried out it was stated that the levee made of the bottom sediments is stable even at the height of 8.0 m, although because of the seepage on the downstream side it is recommended to use a drainage at the toe of the slope.

  16. Metal assessment in sediments from the Guarapiranga Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Coutinho, Suellen N.; Figueiredo, Ana Maria G. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Quináglia, Gilson A., E-mail: sncoutinho@usp.br, E-mail: anamaria@ipen.br, E-mail: gquinaglia@sp.gov.br [Companhia Ambiental do Estado de São Paulo (CETESB), São Paulo, SP (Brazil)

    2017-07-01

    The study of the distribution of metals in sediments is very important from the point of view of environmental pollution once the sediment concentrates metals in aquatic systems and represents a relevant contamination monitor. The analysis of sediments has been used to evaluate the quality of aquatic systems in relation to the concentration of metals. This study aimed to assess sediment contamination by metals in the Guarapiranga Reservoir. Sediment and water samples were analyzed by ICP OES (Inductively Coupled Plasma Optical Emission Spectrometry) for As, Cd, Cr, Cu, Ni, Pb and Zn and by CV AAS (Cold Vapor Atomic Absorption Spectrophotometry) for Hg. The sediment samples results were compared to TEL (Threshold Effect Level) and PEL (Probable Effect Level) guidance values and RRV (Reference Regional Values). Geoaccumulation Index (I{sub geo}) was calculated to evaluate metals pollution degree using reference values established for metals and metalloids in sediments from the Upper Tietê Basin and E{sub H}-pH diagrams were applied to explain chemical forms and bioavailability of toxic metals in sediment samples. In general, most of the analyzed elements exceeded TEL values and Cr, Cu and Zn exceeded RRV guidelines. The high concentrations of Cu found in this reservoir can be explained by the frequent application of CuSO{sub 4} algicide, mainly at sampling site S-03. The I{sub geo} indicated moderated polluted sediments by Zn and moderately to extremely polluted sediments by Cu, especially at S-03, in agreement with the TEL, PEL and RRV values comparison. These results may indicate potential risk of the reservoir water quality. (author)

  17. Metal assessment in sediments from the Guarapiranga Reservoir

    International Nuclear Information System (INIS)

    Coutinho, Suellen N.; Figueiredo, Ana Maria G.; Quináglia, Gilson A.

    2017-01-01

    The study of the distribution of metals in sediments is very important from the point of view of environmental pollution once the sediment concentrates metals in aquatic systems and represents a relevant contamination monitor. The analysis of sediments has been used to evaluate the quality of aquatic systems in relation to the concentration of metals. This study aimed to assess sediment contamination by metals in the Guarapiranga Reservoir. Sediment and water samples were analyzed by ICP OES (Inductively Coupled Plasma Optical Emission Spectrometry) for As, Cd, Cr, Cu, Ni, Pb and Zn and by CV AAS (Cold Vapor Atomic Absorption Spectrophotometry) for Hg. The sediment samples results were compared to TEL (Threshold Effect Level) and PEL (Probable Effect Level) guidance values and RRV (Reference Regional Values). Geoaccumulation Index (I geo ) was calculated to evaluate metals pollution degree using reference values established for metals and metalloids in sediments from the Upper Tietê Basin and E H -pH diagrams were applied to explain chemical forms and bioavailability of toxic metals in sediment samples. In general, most of the analyzed elements exceeded TEL values and Cr, Cu and Zn exceeded RRV guidelines. The high concentrations of Cu found in this reservoir can be explained by the frequent application of CuSO 4 algicide, mainly at sampling site S-03. The I geo indicated moderated polluted sediments by Zn and moderately to extremely polluted sediments by Cu, especially at S-03, in agreement with the TEL, PEL and RRV values comparison. These results may indicate potential risk of the reservoir water quality. (author)

  18. Reservoir Sedimentation and Upstream Sediment Sources: Perspectives and Future Research Needs on Streambank and Gully Erosion

    Science.gov (United States)

    Fox, G. A.; Sheshukov, A.; Cruse, R.; Kolar, R. L.; Guertault, L.; Gesch, K. R.; Dutnell, R. C.

    2016-05-01

    The future reliance on water supply and flood control reservoirs across the globe will continue to expand, especially under a variable climate. As the inventory of new potential dam sites is shrinking, construction of additional reservoirs is less likely compared to simultaneous flow and sediment management in existing reservoirs. One aspect of this sediment management is related to the control of upstream sediment sources. However, key research questions remain regarding upstream sediment loading rates. Highlighted in this article are research needs relative to measuring and predicting sediment transport rates and loading due to streambank and gully erosion within a watershed. For example, additional instream sediment transport and reservoir sedimentation rate measurements are needed across a range of watershed conditions, reservoir sizes, and geographical locations. More research is needed to understand the intricate linkage between upland practices and instream response. A need still exists to clarify the benefit of restoration or stabilization of a small reach within a channel system or maturing gully on total watershed sediment load. We need to better understand the intricate interactions between hydrological and erosion processes to improve prediction, location, and timing of streambank erosion and failure and gully formation. Also, improved process-based measurement and prediction techniques are needed that balance data requirements regarding cohesive soil erodibility and stability as compared to simpler topographic indices for gullies or stream classification systems. Such techniques will allow the research community to address the benefit of various conservation and/or stabilization practices at targeted locations within watersheds.

  19. Sediment transport and capacity change in three reservoirs, Lower Susquehanna River Basin, Pennsylvania and Maryland, 1900-2012

    Science.gov (United States)

    Langland, Michael J.

    2015-01-01

    predict the sediment scour load for daily mean streamflows greater than 300,000 cubic feet per second for the Lower Susquehanna River reservoirs. A compilation of data from various sources produced a range in total sediment transported through the reservoir system and allowed for apportioning to source (watershed or scour) for various streamflows. In 2011, Conowingo Reservoir was estimated to be about 92 percent of sediment storage capacity. Since construction of Conowingo Dam in 1929 through 2012, approximately 470 million tons of sediment was transported down the Susquehanna River into the reservoir system, approximately 290 million tons were trapped, and approximately 180 million tons were transported to Chesapeake Bay. Spatial and estimated total sand deposition in Conowingo Reservoir based on historical sediment cores indicated continued migration of sand downgradient toward the dam and the winnowing of silts and clays near the dam due to scour.

  20. Impacts of climate and land use change on reservoir sedimentation

    Science.gov (United States)

    Impacts of evolving climate and implementation of upstream soil conservation measures on sedimentation of the Fort Cobb Reservoir in West-Central Oklahoma are investigated. Conservation practices before the 1950s were few. Between 1950 and 2008, extensive soil conservation measures were implemented...

  1. The metal spectrum of river sediments from the Denso reservoir

    International Nuclear Information System (INIS)

    Carboo, C.; Brimah, A.K.; Debrah, C.; Serfor Armah, Y.

    1998-01-01

    The heavy metals in the sediment of the Densu reservoir was determined using instrumental neutron activation analysis. In all, about twenty nine elements were identified to be present in the river sediment. Of all the metals determined iron was found to have the the highest concentration with a maximum value of 15.090 g/kg and a minimum of 6.724 g/kg dry weight , other macro elements identified were Al, Na, K, and Ca. The concentration of most of the metals were higher before the major rains than after the rains. Though baseline data for heavy metals in sediment is not available, the values obtained for some of the metals were higher than normal , suggesting some form of heavy metal pollution in the reservoir. (author)

  2. Petrophysical Evaluation of Reservoir Sand Bodies in Kwe Field ...

    African Journals Online (AJOL)

    PROF HORSFALL

    largest known accumulation of recoverable ... barrels of oil and 93 trillion cubic feet of gas (Tuttle et ... continental margin of the Gulf of Guinea in equatorial ... by the 4000 – metre bathymetric contour in areas with great sediment thickness ...

  3. Understanding and Mitigating Reservoir Compaction: an Experimental Study on Sand Aggregates

    Science.gov (United States)

    Schimmel, M.; Hangx, S.; Spiers, C. J.

    2016-12-01

    Fossil fuels continue to provide a source for energy, fuels for transport and chemicals for everyday items. However, adverse effects of decades of hydrocarbons production are increasingly impacting society and the environment. Production-driven reduction in reservoir pore pressure leads to a poro-elastic response of the reservoir, and in many occasions to time-dependent compaction (creep) of the reservoir. In turn, reservoir compaction may lead to surface subsidence and could potentially result in induced (micro)seismicity. To predict and mitigate the impact of fluid extraction, we need to understand production-driven reservoir compaction in highly porous siliciclastic rocks and explore potential mitigation strategies, for example, by using compaction-inhibiting injection fluids. As a first step, we investigate the effect of chemical environment on the compaction behaviour of sand aggregates, comparable to poorly consolidated, highly porous sandstones. The sand samples consist of loose aggregates of Beaujean quartz sand, sieved into a grainsize fraction of 180-212 µm. Uniaxial compaction experiments are performed at an axial stress of 35 MPa and temperature of 80°C, mimicking conditions of reservoirs buried at three kilometres depth. The chemical environment during creep is either vacuum-dry or CO2-dry, or fluid-saturated, with fluids consisting of distilled water, acid solution (CO2-saturated water), alkaline solution (pH 9), aluminium solution (pH 3) and solution with surfactants (i.e., AMP). Preliminary results show that compaction of quartz sand aggregates is promoted in a wet environment compared to a dry environment. It is inferred that deformation is controlled by subcritical crack growth when dry and stress corrosion cracking when wet, both resulting in grain failure and subsequent grain rearrangement. Fluids inhibiting these processes, have the potential to inhibit aggregate compaction.

  4. Development of a national, dynamic reservoir-sedimentation database

    Science.gov (United States)

    Gray, J.R.; Bernard, J.M.; Stewart, D.W.; McFaul, E.J.; Laurent, K.W.; Schwarz, G.E.; Stinson, J.T.; Jonas, M.M.; Randle, T.J.; Webb, J.W.

    2010-01-01

    The importance of dependable, long-term water supplies, coupled with the need to quantify rates of capacity loss of the Nation’s re servoirs due to sediment deposition, were the most compelling reasons for developing the REServoir- SEDimentation survey information (RESSED) database and website. Created under the auspices of the Advisory Committee on Water Information’s Subcommittee on Sedimenta ion by the U.S. Geological Survey and the Natural Resources Conservation Service, the RESSED database is the most comprehensive compilation of data from reservoir bathymetric and dry-basin surveys in the United States. As of March 2010, the database, which contains data compiled on the 1950s vintage Soil Conservation Service’s Form SCS-34 data sheets, contained results from 6,616 surveys on 1,823 reservoirs in the United States and two surveys on one reservoir in Puerto Rico. The data span the period 1755–1997, with 95 percent of the surveys performed from 1930–1990. The reservoir surface areas range from sub-hectare-scale farm ponds to 658 km2 Lake Powell. The data in the RESSED database can be useful for a number of purposes, including calculating changes in reservoir-storage characteristics, quantifying sediment budgets, and estimating erosion rates in a reservoir’s watershed. The March 2010 version of the RESSED database has a number of deficiencies, including a cryptic and out-of-date database architecture; some geospatial inaccuracies (although most have been corrected); other data errors; an inability to store all data in a readily retrievable manner; and an inability to store all data types that currently exist. Perhaps most importantly, the March 2010 version of RESSED database provides no publically available means to submit new data and corrections to existing data. To address these and other deficiencies, the Subcommittee on Sedimentation, through the U.S. Geological Survey and the U.S. Army Corps of Engineers, began a collaborative project in

  5. Mercury in water and bottom sediments from a mexican reservoir

    International Nuclear Information System (INIS)

    Avila Perez, P.; Zarazua Ortega, G.; Barcelo Quintal, D.; Rosas, P.; Diazdelgado, C.

    2001-01-01

    The Lerma-Santiago river's source is located in the State of Mexico. Its drainage basin occupies an area of 129,632 km2. The river receives urban wastewater discharges from 29 municipalities, as well as industrial water discharges, both treated and untreated, mainly from the industrial zones of Toluca, Lerma, Ocoyoacac, Santiago Tianguistengo, Pasteje and Atlacomulco. It is estimated that during a year, the stream receives 536 x 106 m3 of waste waters, which carries 350,946 ton of organic load; 33% of these waste waters come from urban discharges, and 67% originate from industrial discharges. The Jose Antonio Alzate Reservoir fed by the Lerma river is the first significant water reservoir downstream of the main industrial areas in the State of Mexico and both are considered the most contaminated water bodies in the State of Mexico. Mercury concentrations in water and bottom sediments in the Jose Antonio Alzate Reservoir were determined in 6 different sampling zones over a 1-year period. Mercury was measured by instrumental neutron activation analysis (INAA) and irradiated with a thermal neutron flux of 9 x 1012 n. cm-2 s-1 for a period of 26 hours. High variations of mercury concentrations in water in both, soluble and suspended forms, were observed to depend on the sampling season. During the rainy season, rain events contribute with a substantial water volume to modify physicochemical parameters like pH, which dilute chemical species in the Alzate Reservoir. There are evidence that in the Jose Antonio Alzate reservoir, sedimentation and adsorption act as a natural cleaning process, decreasing the dissolved concentrations and increasing the metallic content of the sediments. A negative gradient was identified for mercury concentrations, from the Lerma river inlet to Alzate Reservoir dam, which demonstrates the considerable influence of the Lerma river inlet. This gradient also proves the existence of a metal recycling process between water and sediment, while the

  6. Biodiesel production from sediments of a eutrophic reservoir

    International Nuclear Information System (INIS)

    Kuchkina, A.Yu.; Gladyshev, M.I.; Sushchik, N.N.; Kravchuk, E.S.; Kalachova, G.S.

    2011-01-01

    Sediments from eutrophic reservoir Bugach (Siberia, Russia) were tested for possibility to produce biodiesel. We supposed that the sediments could be a promising biodiesel producer. The major reason of high price of biodiesel fuel is cost of a raw material. The use of dredging sediments for biodiesel production reduces production costs, because the dredging sediments are by-products which originated during lake restoration actions, and are free of cost raw materials. Lipid content in sediments was 0.24% of dry weight. To assess the potential of from sediments as a substitute of diesel fuel, the properties of the biodiesel such as cetane number, iodine number and heat of combustion were calculated. All of this parameters complied with limits established by EN 14214 and EN 14213 related to biodiesel quality. -- Highlights: → Dredging sediments were considered as a new feedstock for biodiesel production. → Lipid and fatty acid content in the sediments were determined. → Main properties of the biodiesel were calculated basing on fatty acid composition. → The properties well complied with limits established in biodiesel standards.

  7. Sedimentation in Rio La Venta Canyon in Netzahualcoyotl Reservoir, Chiapas, Mexico

    Science.gov (United States)

    de La Fuente, J. A.; Lisle, T.; Velasquez, J.; Allison, B. L.; Miller, A.

    2002-12-01

    Sedimentation of Rio La Venta as it enters the Netzahualcoyotl Reservoir in Chiapas, Mexico, threatens a unique part of the aquatic ecosystem. Rio La Venta enters the reservoir via a narrow canyon about 16 km long with spectacular, near-vertical limestone bluffs up to 320 m high and inhabited by the flora and fauna of a pristine tropical forest. Karst terrain underlies most of the Rio La Venta basin in the vicinity of the reservoir, while deeply weathered granitic terrain underlies the Rio Negro basin, and the headwaters of the Rio La Venta to the south. The Rio Negro joins Rio La Venta 3 km downstream of the upper limit of the reservoir and delivers the bulk of the total clastic sediment (mostly sand and finer material). The canyon and much of the contributing basin lie within the Reserva de la Biosfera, Selva El Ocote, administered by the Comision Nacional de Areas Naturales Protegidas, part of the Secretaria de Medioambiente y Recursos Naturales. The Klamath National Forest Forest has cooperated with its Mexican counterparts since 1993 in natural resource management, neo-tropical bird inventories, wildfire management, and more recently in watershed analyses. Rates of sedimentation are estimated from bathymetric surveys conducted in March, 2002. A longitudinal profile down the inundated canyon during a high reservoir level shows an inflection from a slope of 0.0017 to one of 0.0075 at 7.2 km downstream of the mouth of Rio Negro. The bed elevation at this point corresponds to the lowest reservoir level, suggesting that the gentler sloping bed upstream is formed by fluvial processes during drawdown and that downstream by pluvial processes. Using accounts that boats could access Rio Negro during low water levels in 1984, we estimate an annual sedimentation rate of roughly 3 million cubic meters per year. This suggests that boats might no longer be able to access the most spectacular section of canyon upstream of Rio Negro within a decade, depending on how the

  8. Sedimentation and the Economics of Selecting an Optimum Reservoir Size

    Science.gov (United States)

    Miltz, David; White, David C.

    1987-08-01

    This paper attempts to develop an easily reproducible methodology for the economic selection of an optimal reservoir size given an annual sedimentation rate. The optimal capacity is that at which the marginal cost of constructing additional storage capacity is equal to the dredging costs avoided by having that additional capacity available to store sediment. The cost implications of misestimating dredging costs, construction costs, and sediment delivery rates are investigated. In general, it is shown that oversizing is a rational response to uncertainty in the estimation of parameters. The sensitivity of the results to alternative discount rates is also discussed. The theoretical discussion is illustrated with a case study drawn from Highland Silver Lake in southwestern Illinois.

  9. Estimated cumulative sediment trapping in future hydropower reservoirs in Africa

    Science.gov (United States)

    Lucía, Ana; Berlekamp, Jürgen; Zarfl, Christiane

    2017-04-01

    Despite a rapid economic development in Sub-Saharan Africa, almost 70% of the human population in this area remain disconnected from electricity access (International Energy Agency 2011). Mitigating climate change and a search for renewable, "climate neutral" electricity resources are additional reasons why Africa will be one key centre for future hydropower dam building, with only 8% of the technically feasible hydropower potential actually exploited. About 300 major hydropower dams with a total capacity of 140 GW are currently under construction (11.4%) or planned (88.6%) (Zarfl et al. 2015). Despite the benefits of hydropower dams, fragmentation of the rivers changes the natural flow, temperature and sediment regime. This has consequences for a high number of people that directly depend on the primary sector linked to rivers and floodplains. But sediment trapping in the reservoir also affects dam operation and decreases its life span. Thus, the objective of this work is to quantify the dimension of sediment trapping by future hydropower dams in African river basins. Soil erosion is described with the universal soil loss equation (Wischmeier & Smith 1978) and combined with the connectivity index (Cavalli et al. 2013) to estimate the amount of eroded soil that reaches the fluvial network and finally ends up in the existing (Lehner et al. 2011) and future reservoirs (Zarfl et al. 2015) per year. Different scenarios assuming parameter values from the literature are developed to include model uncertainty. Estimations for existing dams will be compared with literature data to evaluate the applied estimation method and scenario assumptions. Based on estimations for the reservoir volume of the future dams we calculated the potential time-laps of the future reservoirs due to soil erosion and depending on their planned location. This approach could support sustainable decision making for the location of future hydropower dams. References Cavalli, M., Trevisani, S., Comiti

  10. Turbulence and sediment transport over sand dunes and ripples

    Science.gov (United States)

    Bennis, A.; Le Bot, S.; lafite, R.; Bonneton, P.; Ardhuin, F.

    2013-12-01

    Several bedforms are present near to the surfzone of natural beaches. Dunes and ripples are frequently observed. Understanding the turbulence over these forms is essential for the sediment transport. The turbulent flow and the suspended sand particles interact with each other. At the moment, the modelling strategy for turbulence is still a challenge. According to the spatial scales, some different methods to model the turbulence are employed, in particular the RANS (Reynolds Averaged Navier-Stokes) and the LES (Large Eddy Simulation). A hybrid method combining both RANS and LES is set up here. We have adapted this method, initially developed for atmospheric flow, to the oceanic flow. This new method is implemented inside the 3D hydrodynamic model, MARS 3D, which is forced by waves. LES is currently the best way to simulate turbulent flow but its higher cost prevents it from being used for large scale applications. So, here we use RANS near the bottom while LES is set elsewhere. It allows us minimize the computational cost and ensure a better accuracy of the results than with a fully RANS model. In the case of megaripples, the validation step was performed with two sets of field data (Sandy Duck'97 and Forsoms'13) but also with the data from Dune2D model which uses only RANS for turbulence. The main findings are: a) the vertical profiles of the velocity are similar throughout the data b) the turbulent kinetic energy, which was underestimated by Dune2D, is in line with the observations c) the concentration of the suspended sediment is simulated with a better accuracy than with Dune2D but this remains lower than the observations.

  11. Sediment transport and mixing depth on a coral reef sand apron

    Science.gov (United States)

    Vila-Concejo, Ana; Harris, Daniel L.; Power, Hannah E.; Shannon, Amelia M.; Webster, Jody M.

    2014-10-01

    This paper investigates the mechanics of sediment transport on a subtidal sand apron located on a coral reef environment. In this environment 100% of the sediment is carbonate bioclasts generated in situ. The sand apron is located on the back reef and only affected by waves during high tides. It is commonly accepted in the literature that sand aprons are features that prograde lagoonwards and that most of the progradation occurs during high-energy events. Measurements of water depths, waves, currents and near bed suspended sediment concentrations (all at 10 Hz) on the sand apron were undertaken over a nine day intensive field campaign over both spring and neap tides; waves and tides were also measured in the lagoon. The topography and bathymetry of the sand apron were measured and mixing depth was obtained on three transects using depth of disturbance rods. We found that sediment transport on sand aprons is not solely restricted to high-energy events but occurs on a daily basis during spring tides. The main factor controlling the sediment transport was the water depth above the bed, with depths of 2-2.3 m allowing waves to promote the most sediment transport. This corresponds to a depth over the reef crest of 1.6-1.9 m. The second most important control was waves; transport was observed when Hs on the apron was 0.1 m or greater. In contrast, current magnitude was not a controlling mechanism for sediment entrainment but did affect sediment transport. The morphology of the sand apron was shown to affect the direction of currents with the currents also expected to influence the morphology of the sand apron. The currents measured during this field campaign were aligned with a shallow channel in the sand apron. Mixing depths were small (< 2.5 cm) yet they were larger than the values predicted by empirical formulae for gentle siliciclastic ocean beaches.

  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. A Tool for Assessing Future Capacity Loss Due to Sedimentation in the United States' Reservoirs

    Science.gov (United States)

    Pinson, A. O.; Baker, B.; White, K. D.

    2017-12-01

    Federal reservoirs are critical components of the United States' water supply, flood risk management, hydropower and navigation infrastructure. These reservoirs included capacity for storage loss due to the deposition of sediment by inflowing streams in their original design. However, the actual rate of capacity loss experienced is controlled in part by climate, topography, soils, and land use/land cover, and may vary from the design. To assess the current and future vulnerability of its reservoirs to sedimentation. USACE has developed an online planning tool to identify USACE reservoirs where sedimentation is currently a problem (e.g., sedimentation rate exceeds design sedimentation rate, or zone losses disproportionately affect authorized purposes), and reservoirs where rates are expected to increase significantly in the future. The goal is to be able to prioritize operation and maintenance actions to minimize the effects of reservoir capacity loss on authorized purposes and help maximize reservoir use life.

  14. Sedimentation rate and {sup 210}Pb sediment dating at Apipucos reservoir, Recife, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, Marcela D.C. de; Silva, Danubia B. da; Cunha, Manuela S. da; Rodrigues, Kelia R.G.; Pedroza, Eryka H.; Melo, Roberto T. de; Oliveira, Aristides; Hazin, Clovis A.; Souza, Vivianne L.B. de, E-mail: rtmelo@cnen.gov.b, E-mail: chazin@cnen.gov.b, E-mail: vlsouza@cnen.gov.b [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-07-01

    The Apipucos Reservoir is located in Recife, State of Pernambuco, and, several districts of the metropolitan area use this reservoir to dispose waste and sewage. Dating sediments uses {sup 210}Pb from the atmosphere which is formed as a result of {sup 222}Rn emanation from the soil. Atmospheric lead, carried by rain, is called non-supported {sup 21}'0Pb, to differentiate it from the one contained in the sediment, in balance with the {sup 226}Ra. The model chosen for dating sediments depends on certain conditions: in an environment where the amount of sediment influx can vary, the constant rate of supply model is adopted. On the other hand, in environments where the sedimentation rate is constant and the sediment can be considered to have a constant initial concentration of unsupported {sup 210}Pb and the (CIC) model is applied. A 70-cm long, 5-cm internal-diameter wide core was collected for sediment dating. Each core was sliced, into 5 or 10 cm intervals. Samples were dried at 105 deg C, and about 5 g dry material from each sample was dissolved with acids. The {sup 210}Pb and {sup 226}Ra contents were separated and determined by beta and alpha counting by using a gas-flow proportional counter. Sediment ages were calculated by the two models, and for the second and fourth sampling points, both models could be used. The results showed an increase in sedimentation rate over the last 50 - 60 years. We can conclude that the top sediment layer is dated from 30 years ago. We can also conclude that the CRS is the best applicable model to use in this area. (author)

  15. SEDIMENT ANALYSIS NETWORK FOR DECISION SUPPORT (SANDS) LANDSAT GEOLOGICAL SURVEY OF AL (GSA) ANALYSIS V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Sediment Analysis Network for Decision Support (SANDS) Landsat Geological Survey of AL (GSA) Analysis dataset analyzed changes in the coastal shoreline and...

  16. Influence of porewater advection on denitrification in carbonate sands: Evidence from repacked sediment column experiments

    DEFF Research Database (Denmark)

    Santos, Isaac R.; Eyre, Bradley D.; Glud, Ronnie N.

    2012-01-01

    Porewater flow enhances mineralization rates in organic-poor permeable sands. Here, a series of sediment column experiments were undertaken to assess the potential effect of advective porewater transport on denitrification in permeable carbonate sands collected from Heron Island (Great Barrier Re...

  17. Assessment of managed aquifer recharge at Sand Hollow Reservoir, Washington County, Utah, updated to conditions through 2014

    Science.gov (United States)

    Marston, Thomas M.; Heilweil, Victor M.

    2016-09-08

    Sand Hollow Reservoir in Washington County, Utah, was completed in March 2002 and is operated primarily for managed aquifer recharge by the Washington County Water Conservancy District. From 2002 through 2014, diversions of about 216,000 acre-feet from the Virgin River to Sand Hollow Reservoir have allowed the reservoir to remain nearly full since 2006. Groundwater levels in monitoring wells near the reservoir rose through 2006 and have fluctuated more recently because of variations in reservoir stage and nearby pumping from production wells. Between 2004 and 2014, about 29,000 acre-feet of groundwater was withdrawn by these wells for municipal supply. In addition, about 31,000 acre-feet of shallow seepage was captured by French drains adjacent to the North and West Dams and used for municipal supply, irrigation, or returned to the reservoir. From 2002 through 2014, about 127,000 acre-feet of water seeped beneath the reservoir to recharge the underlying Navajo Sandstone aquifer.Water quality continued to be monitored at various wells in Sand Hollow during 2013–14 to evaluate the timing and location of reservoir recharge as it moved through the aquifer. Changing geochemical conditions at monitoring wells WD 4 and WD 12 indicate rising groundwater levels and mobilization of vadose-zone salts, which could be a precursor to the arrival of reservoir recharge.

  18. Assessment of managed aquifer recharge from Sand Hollow Reservoir, Washington County, Utah, updated to conditions in 2010

    Science.gov (United States)

    Heilweil, Victor M.; Marston, Thomas M.

    2011-01-01

    Sand Hollow Reservoir in Washington County, Utah, was completed in March 2002 and is operated primarily for managed aquifer recharge by the Washington County Water Conservancy District. From 2002 through 2009, total surface-water diversions of about 154,000 acre-feet to Sand Hollow Reservoir have allowed it to remain nearly full since 2006. Groundwater levels in monitoring wells near the reservoir rose through 2006 and have fluctuated more recently because of variations in reservoir water-level altitude and nearby pumping from production wells. Between 2004 and 2009, a total of about 13,000 acre-feet of groundwater has been withdrawn by these wells for municipal supply. In addition, a total of about 14,000 acre-feet of shallow seepage was captured by French drains adjacent to the North and West Dams and used for municipal supply, irrigation, or returned to the reservoir.From 2002 through 2009, about 86,000 acre-feet of water seeped beneath the reservoir to recharge the underlying Navajo Sandstone aquifer. Water-quality sampling was conducted at various monitoring wells in Sand Hollow to evaluate the timing and location of reservoir recharge moving through the aquifer. Tracers of reservoir recharge include major and minor dissolved inorganic ions, tritium, dissolved organic carbon, chlorofluorocarbons, sulfur hexafluoride, and noble gases. By 2010, this recharge arrived at monitoring wells within about 1,000 feet of the reservoir.

  19. 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

  20. The effect of oil sands tailings pond sediments on embryo-larval walleye (Sander vitreus).

    Science.gov (United States)

    Raine, J C; Turcotte, D; Tumber, V; Peru, K M; Wang, Z; Yang, C; Headley, J V; Parrott, J L

    2017-10-01

    Walleye (Sander vitreus) are a commercially important North American fish species that inhabit the Athabasca River. This river flows through the Athabasca oil sands where natural sources of bitumen erode from the McMurray formation. Little information is available on responses of walleye embryos to oil sands tailings pond sediments in a laboratory setting. The current study describes the design and implementation of a daily-renewal bioassay to assess the potential effects of tailings pond sediments from the Athabasca oil sands area on walleye development. Developing walleye embryos were exposed to increasing concentrations of two tailings pond sediments (collected in the Athabasca oil sands area) until the completion of yolk absorption in control fish. Sediments from the tailings pond represent a mixture of polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs. During the 31 day exposure, the walleye were examined for mortalities, weight, length and developmental abnormalities to provide an initial evaluation of the effects of the oil sands tailings pond sediments. Walleye embryo survival differed between the tailings pond sediments, and survival decreased with increasing sediment concentration. Alkylated PAH content differed between the two tailings pond sediments and lower embryo survival corresponded to higher total and alkylated PAH content. Tailings pond sediment-exposed walleye exhibited a delay in development, as well as increased percentages of larvae with heart and yolk sac edema, and cranial and spinal malformations. These abnormalities in development are often associated with PAH and alkylated PAH exposure. This study provides an exposure design that can be used to assess sediment toxicity to early developmental stages of a fish species not commonly tested in the lab, and lays the groundwork for future studies with this and other difficult-to-culture species. These results offer information on the potential effects of tailings pond sediments

  1. On the influence of suspended sediment transport on the generation of offshore sand waves

    NARCIS (Netherlands)

    Sterlini-Van der Meer, Fenneke; Hulscher, Suzanne J.M.H.; van den Berg, J.; Geurts, Bernardus J.; Clercx, H.J.H.; Uijttewaal, Wim

    2007-01-01

    Sand waves are bed-forms occurring in shallow seas. Although their characteristics are mainly affected by bed load transport, during rough weather suspended sediment transport can influence their characteristics. As a first step to model these influences, we added suspended sediment transport to a

  2. Dynamics of fluctuations of Cs-137 contents in the bottom sediment in limnetic dam reservoir Goczalkowice

    International Nuclear Information System (INIS)

    Kwapulinski, J.; Majchrzyk, H.; Kalita, T.; Miroslawski, J.

    1986-01-01

    The results of 137 Cs studies in bottom sediment in the Goczalkowice reservoir are presented. The determined coefficients of aquatic migration, difusion in bottom sediment and water in vertical section confirm zonal nature of 137 Cs occurrance and accumulation in the reservoir. 5 refs., 1 fig., 6 tabs. (author)

  3. An alternative approach to assessing feasibility of flushing sediment from reservoirs

    Directory of Open Access Journals (Sweden)

    Elfimov Valeriy Ivanovich

    2014-07-01

    Full Text Available Effective parameters on feasibility of sediment flushing through reservoirs include hydrological, hydraulic, and topographic properties of the reservoirs. In this study, the performances of the Decision tree forest (DTF and Group method of data handling (GMDH for assessing feasibility of flushing sediment from reservoirs, were investigated. In this way, Decision tree Forest, that combines multiple Decision tree, used to evaluate the relative importance of factors affecting flushing sediment. At the second step, GMDH deployed to predict the feasibility of flushing sediment from reservoirs. Results indicate that these models, as an efficient novel approach with an acceptable range of error, can be used successfully for assessing feasibility of flushing sediment from reservoirs.

  4. Assessment of managed aquifer recharge at Sand Hollow Reservoir, Washington County, Utah, updated to conditions in 2012

    Science.gov (United States)

    Marston, Thomas M.; Heilweil, Victor M.

    2013-01-01

    Sand Hollow Reservoir in Washington County, Utah, was completed in March 2002 and is operated primarily for managed aquifer recharge by the Washington County Water Conservancy District. From 2002 through 2011, surface-water diversions of about 199,000 acre-feet to Sand Hollow Reservoir have allowed the reservoir to remain nearly full since 2006. Groundwater levels in monitoring wells near the reservoir rose through 2006 and have fluctuated more recently because of variations in reservoir altitude and nearby pumping from production wells. Between 2004 and 2011, a total of about 19,000 acre-feet of groundwater was withdrawn by these wells for municipal supply. In addition, a total of about 21,000 acre-feet of shallow seepage was captured by French drains adjacent to the North and West Dams and used for municipal supply, irrigation, or returned to the reservoir. From 2002 through 2011, about 106,000 acre-feet of water seeped beneath the reservoir to recharge the underlying Navajo Sandstone aquifer. Water quality was sampled at various monitoring wells in Sand Hollow to evaluate the timing and location of reservoir recharge as it moved through the aquifer. Tracers of reservoir recharge include major and minor dissolved inorganic ions, tritium, dissolved organic carbon, chlorofluorocarbons, sulfur hexafluoride, and noble gases. By 2012, this recharge arrived at four monitoring wells located within about 1,000 feet of the reservoir. Changing geochemical conditions at five other monitoring wells could indicate other processes, such as changing groundwater levels and mobilization of vadose-zone salts, rather than arrival of reservoir recharge.

  5. Electrical anisotropy of gas hydrate-bearing sand reservoirs in the Gulf of Mexico

    Science.gov (United States)

    Cook, Anne E.; Anderson, Barbara I.; Rasmus, John; Sun, Keli; Li, Qiming; Collett, Timothy S.; Goldberg, David S.

    2012-01-01

    We present new results and interpretations of the electricalanisotropy and reservoir architecture in gashydrate-bearingsands using logging data collected during the Gulf of MexicoGasHydrate Joint Industry Project Leg II. We focus specifically on sandreservoirs in Hole Alaminos Canyon 21 A (AC21-A), Hole Green Canyon 955 H (GC955-H) and Hole Walker Ridge 313 H (WR313-H). Using a new logging-while-drilling directional resistivity tool and a one-dimensional inversion developed by Schlumberger, we resolve the resistivity of the current flowing parallel to the bedding, R| and the resistivity of the current flowing perpendicular to the bedding, R|. We find the sandreservoir in Hole AC21-A to be relatively isotropic, with R| and R| values close to 2 Ω m. In contrast, the gashydrate-bearingsandreservoirs in Holes GC955-H and WR313-H are highly anisotropic. In these reservoirs, R| is between 2 and 30 Ω m, and R| is generally an order of magnitude higher. Using Schlumberger's WebMI models, we were able to replicate multiple resistivity measurements and determine the formation resistivity the gashydrate-bearingsandreservoir in Hole WR313-H. The results showed that gashydrate saturations within a single reservoir unit are highly variable. For example, the sand units in Hole WR313-H contain thin layers (on the order of 10-100 cm) with varying gashydrate saturations between 15 and 95%. Our combined modeling results clearly indicate that the gashydrate-bearingsandreservoirs in Holes GC955-H and WR313-H are highly anisotropic due to varying saturations of gashydrate forming in thin layers within larger sand units.

  6. Sediment pollution characteristics and in situ control in a deep drinking water reservoir.

    Science.gov (United States)

    Zhou, Zizhen; Huang, Tinglin; Li, Yang; Ma, Weixing; Zhou, Shilei; Long, Shenghai

    2017-02-01

    Sediment pollution characteristics, in situ sediment release potential, and in situ inhibition of sediment release were investigated in a drinking water reservoir. Results showed that organic carbon (OC), total nitrogen (TN), and total phosphorus (TP) in sediments increased from the reservoir mouth to the main reservoir. Fraction analysis indicated that nitrogen in ion exchangeable form and NaOH-extractable P (Fe/Al-P) accounted for 43% and 26% of TN and TP in sediments of the main reservoir. The Risk Assessment Code for metal elements showed that Fe and Mn posed high to very high risk. The results of the in situ reactor experiment in the main reservoir showed the same trends as those observed in the natural state of the reservoir in 2011 and 2012; the maximum concentrations of total OC, TN, TP, Fe, and Mn reached 4.42mg/L, 3.33mg/L, 0.22mg/L, 2.56mg/L, and 0.61mg/L, respectively. An in situ sediment release inhibition technology, the water-lifting aerator, was utilized in the reservoir. The results of operating the water-lifting aerator indicated that sediment release was successfully inhibited and that OC, TN, TP, Fe, and Mn in surface sediment could be reduced by 13.25%, 15.23%, 14.10%, 5.32%, and 3.94%, respectively. Copyright © 2016. Published by Elsevier B.V.

  7. Sedimentation, sediment quality, and upstream channel stability, John Redmond Reservoir, east-central Kansas, 1964-2009

    Science.gov (United States)

    Juracek, Kyle E.

    2010-01-01

    A combination of available bathymetric-survey information, bottom-sediment coring, and historical streamgage information was used to investigate sedimentation, sediment quality, and upstream channel stability for John Redmond Reservoir, east-central Kansas. Ongoing sedimentation is reducing the ability of the reservoir to serve several purposes including flood control, water supply, and recreation. The total estimated volume and mass of bottom sediment deposited between 1964 and 2009 in the conservation pool of the reservoir was 1.46 billion cubic feet and 55.8 billion pounds, respectively. The estimated sediment volume occupied about 41 percent of the conservation-pool, water-storage capacity of the reservoir. Water-storage capacity in the conservation pool has been lost to sedimentation at a rate of about 1 percent annually. Mean annual net sediment deposition since 1964 in the conservation pool of the reservoir was estimated to be 1.24 billion pounds per year. Mean annual net sediment yield from the reservoir basin was estimated to be 411,000 pounds per square mile per year Information from sediment cores shows that throughout the history of John Redmond Reservoir, total nitrogen concentrations in the deposited sediment generally were uniform indicating consistent nitrogen inputs to the reservoir. Total phosphorus concentrations in the deposited sediment were more variable than total nitrogen indicating the possibility of changing phosphorus inputs to the reservoir. As the principal limiting factor for primary production in most freshwater environments, phosphorus is of particular importance because increased inputs can contribute to accelerated reservoir eutrophication and the production of algal toxins and taste-and-odor compounds. The mean annual net loads of total nitrogen and total phosphorus deposited in the bottom sediment of the reservoir were estimated to be 2,350,000 pounds per year and 1,030,000 pounds per year, respectively. The estimated mean annual

  8. Storage Capacity and Sedimentation of Loch Lomond Reservoir, Santa Cruz, California, 1998

    Science.gov (United States)

    McPherson, Kelly R.; Harmon, Jerry G.

    2000-01-01

    In 1998, a bathymetric survey was done to determine the storage capacity and the loss of capacity owing to sedimentation of Loch Lomond Reservoir in Santa Cruz County, California. Results of the survey indicate that the maximum capacity of the reservoir is 8,991 acre-feet in November 1998. The results of previous investigations indicate that storage capacity of the reservoir is less than 8,991 acre-feet. The storage capacity determined from those investigations probably were underestimated because of limitations of the methods and the equipment used. The volume of sedimentation in a reservoir is considered equal to the decrease in storage capacity. To determine sedimentation in Loch Lomond Reservoir, change in storage capacity was estimated for an upstream reach of the reservoir. The change in storage capacity was determined by comparing a 1998 thalweg profile (valley floor) of the reservoir with thalweg profiles from previous investigations; results of the comparison indicate that sedimentation is occurring in the upstream reach. Cross sections for 1998 and 1982 were compared to determine the magnitude of sedimentation in the upstream reach of the reservoir. Results of the comparison, which were determined from changes in the cross-sectional areas, indicate that the capacity of the reservoir decreased by 55 acre-feet.

  9. Sediment oxygen demand of wetlands in the oil sands region of north-eastern Alberta

    International Nuclear Information System (INIS)

    Slama, C.; Ciborowski, J.J.; Gardner Costa, J.

    2009-01-01

    Reclaimed land in the Alberta oil sands mining area contains both reference and oil sands process-affected wetlands constructed using varying sediment compositions. The sediments derived from oil sands process materials (OSPM) may alter the biochemical reactions that take place and affect the sediment oxygen demand (SOD), which is a key factor that contributes to oxygen depletion. This presentation reported on a study in which SOD was measured in a suite of constructed wetlands of different ages, with or without OSPM and topsoil. The purpose of the study was to clarify the role of SOD in wetland function and in the reclamation process. Dissolved oxygen loggers were inserted into dome-shaped chambers on the sediment to measure changes in oxygen demand. Complementary measurements of respiration (CO 2 elution) were used to quantify the biological sediment oxygen demand (BSOD) component of SOD. The chemical sediment oxygen demand (CSOD) was then determined by subtraction from SOD. Wetlands reclaimed using OSPM are expected to have a lower BSOD to CSOD ratio than reference wetlands. Residual ammonia in OSPM sediments may react with sulphate and bind phosphorus. This reduces phosphorus bioavailability and may impede submergent macrophyte growth. As such, wetlands affected by CSOD will have fewer submerged macrophytes than BSOD dominant wetlands.

  10. Preliminary Three-Dimensional Simulation of Sediment and Cesium Transport in the Ogi Dam Reservoir using FLESCOT – Task 6, Subtask 2

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Yasuo; Kurikami, Hiroshi; Yokuda, Satoru T.

    2014-03-28

    After the accident at the Fukushima Daiichi Nuclear Power Plant in March 2011, the Japan Atomic Energy Agency and the Pacific Northwest National Laboratory initiated a collaborative project on environmental restoration. In October 2013, the collaborative team started a task of three-dimensional modeling of sediment and cesium transport in the Fukushima environment using the FLESCOT (Flow, Energy, Salinity, Sediment Contaminant Transport) code. As the first trial, we applied it to the Ogi Dam Reservoir that is one of the reservoirs in the Japan Atomic Energy Agency’s (JAEA’s) investigation project. Three simulation cases under the following different temperature conditions were studied: • incoming rivers and the Ogi Dam Reservoir have the same water temperature • incoming rivers have lower water temperature than that of the reservoir • incoming rivers have higher water temperature than that of the reservoir. The preliminary simulations suggest that seasonal temperature changes influence the sediment and cesium transport. The preliminary results showed the following: • Suspended sand, and cesium adsorbed by sand, coming into the reservoirs from upstream rivers is deposited near the reservoir entrance. • Suspended silt, and cesium adsorbed by silt, is deposited farther in the reservoir. • Suspended clay, and cesium adsorbed by clay, travels the farthest into the reservoir. With sufficient time, the dissolved cesium reaches the downstream end of the reservoir. This preliminary modeling also suggests the possibility of a suitable dam operation to control the cesium migration farther downstream from the dam. JAEA has been sampling in the Ogi Dam Reservoir, but these data were not yet available for the current model calibration and validation for this reservoir. Nonetheless these preliminary FLESCOT modeling results were qualitatively valid and confirmed the applicability of the FLESCOT code to the Ogi Dam Reservoir, and in general to other reservoirs in

  11. A Study of Sedimentation at the River Estuary on the Change of Reservoir Storage

    Directory of Open Access Journals (Sweden)

    Iskahar

    2018-01-01

    Full Text Available Estuary of the river that leads to the reservoir has characteristics include: relatively flat, there is a change in the increase of wet cross-sectional area and backwater. The backwater will cause the flow velocity to be reduced, so that the grains of sediment with a certain diameter carried by the flow will settle in the estuary of the river. The purpose of this research is to know the distribution and sedimentation pattern at the river estuary that leads to the reservoir with the change of water level in the reservoir storage, so the solution can be found to remove / reduce sediment before entering the reservoir. The method used is the experimental, by making the physical model of the river estuary leading to the reservoir. This study expects a solution to reduce sedimentation, so that sedimentation can be removed / minimized before entering the reservoir. This research tries to apply bypass channel to reduce the sedimentation at the river estuary. Bypass channels can be applied to overcome sedimentation at the river estuary, but in order for the sediment to be removed optimally, it is necessary to modify the mouth of bypass channel and channel angle.

  12. [Distribution Characteristics and Pollution Status Evaluation of Sediments Nutrients in a Drinking Water Reservoir].

    Science.gov (United States)

    Huang, Ting-lin; Liu, Fei; Shi, Jian-chao

    2016-01-15

    The main purpose of this paper is to illustrate the influence of nutrients distribution in sediments on the eutrophication of drinking water reservoir. The sediments of three representative locations were field-sampled and analyzed in laboratory in March 2015. The distribution characteristics of TOC, TN and TP were measured, and the pollution status of sediments was evaluated by the comprehensive pollution index and the manual for sediment quality assessment. The content of TOC in sediments decreased with depth, and there was an increasing trend of the nitrogen content. The TP was enriched in surface sediment, implying the nutrients load in Zhoucun Reservoir was aggravating as the result of human activities. Regression analysis indicated that the content of TOC in sediments was positively correlated with contents of TN and TP in sediments. The TOC/TN values reflected that the vascular land plants, which contain cellulose, were the main source of organic matter in sediments. The comprehensive pollution index analysis result showed that the surface sediments in all three sampling sites were heavily polluted. The contents of TN and TP of surface sediments in three sampling sites were 3273-4870 mg x kg(-1) and 653-2969 mg x kg(-1), and the content of TOC was 45.65-83.00 mg x g(-1). According to the manual for sediment quality assessment, the TN, TP and TOC contents in sediments exceed the standard values for the lowest level of ecotoxicity, so there is a risk of eutrophication in Zhoucun Reservoir.

  13. Quantifying suspended sediment loads delivered to Cheney Reservoir, Kansas: Temporal patterns and management implications

    Science.gov (United States)

    Stone, Mandy L.; Juracek, Kyle E.; Graham, Jennifer L.; Foster, Guy

    2015-01-01

    Cheney Reservoir, constructed during 1962 to 1965, is the primary water supply for the city of Wichita, the largest city in Kansas. Sediment is an important concern for the reservoir as it degrades water quality and progressively decreases water storage capacity. Long-term data collection provided a unique opportunity to estimate the annual suspended sediment loads for the entire history of the reservoir. To quantify and characterize sediment loading to Cheney Reservoir, discrete suspended sediment samples and continuously measured streamflow data were collected from the North Fork Ninnescah River, the primary inflow to Cheney Reservoir, over a 48-year period. Continuous turbidity data also were collected over a 15-year period. These data were used together to develop simple linear regression models to compute continuous suspended sediment concentrations and loads from 1966 to 2013. The inclusion of turbidity as an additional explanatory variable with streamflow improved regression model diagnostics and increased the amount of variability in suspended sediment concentration explained by 14%. Using suspended sediment concentration from the streamflow-only model, the average annual suspended sediment load was 102,517 t (113,006 tn) and ranged from 4,826 t (5,320 tn) in 1966 to 967,569 t (1,066,562 tn) in 1979. The sediment load in 1979 accounted for about 20% of the total load over the 48-year history of the reservoir and 92% of the 1979 sediment load occurred in one 24-hour period during a 1% annual exceedance probability flow event (104-year flood). Nearly 60% of the reservoir sediment load during the 48-year study period occurred in 5 years with extreme flow events (9% to 1% annual exceedance probability, or 11- to 104-year flood events). A substantial portion (41%) of sediment was transported to the reservoir during five storm events spanning only eight 24-hour periods during 1966 to 2013. Annual suspended sediment load estimates based on streamflow were, on

  14. Scale-dependent gas hydrate saturation estimates in sand reservoirs in the Ulleung Basin, East Sea of Korea

    Science.gov (United States)

    Lee, Myung Woong; Collett, Timothy S.

    2013-01-01

    Through the use of 2-D and 3-D seismic data, several gas hydrate prospects were identified in the Ulleung Basin, East Sea of Korea and thirteen drill sites were established and logging-while-drilling (LWD) data were acquired from each site in 2010. Sites UBGH2–6 and UBGH2–10 were selected to test a series of high amplitude seismic reflections, possibly from sand reservoirs. LWD logs from the UBGH2–6 well indicate that there are three significant sand reservoirs with varying thickness. Two upper sand reservoirs are water saturated and the lower thinly bedded sand reservoir contains gas hydrate with an average saturation of 13%, as estimated from the P-wave velocity. The well logs at the UBGH2–6 well clearly demonstrated the effect of scale-dependency on gas hydrate saturation estimates. Gas hydrate saturations estimated from the high resolution LWD acquired ring resistivity (vertical resolution of about 5–8 cm) reaches about 90% with an average saturation of 28%, whereas gas hydrate saturations estimated from the low resolution A40L resistivity (vertical resolution of about 120 cm) reaches about 25% with an average saturation of 11%. However, in the UBGH2–10 well, gas hydrate occupies a 5-m thick sand reservoir near 135 mbsf with a maximum saturation of about 60%. In the UBGH2–10 well, the average and a maximum saturation estimated from various well logging tools are comparable, because the bed thickness is larger than the vertical resolution of the various logging tools. High resolution wireline log data further document the role of scale-dependency on gas hydrate calculations.

  15. Sedimentation in the Bremgarten-Zufikon-reservoir on the Reuss river

    Energy Technology Data Exchange (ETDEWEB)

    Jaeggi, M.; Lambert, A.; Smart, G.

    1981-01-01

    Sedimentation processes in the reservoir and in the lacustrine realm of Unterlunkhofen are investigated by field measurements and numerical simulation. This procedure provides an approximation of the silting-up progress.

  16. Turbulent Flow and Sand Dune Dynamics: Identifying Controls on Aeolian Sediment Transport

    Science.gov (United States)

    Weaver, C. M.; Wiggs, G.

    2007-12-01

    Sediment transport models are founded on cubic power relationships between the transport rate and time averaged flow parameters. These models have achieved limited success and recent aeolian and fluvial research has focused on the modelling and measurement of sediment transport by temporally varying flow conditions. Studies have recognised turbulence as a driving force in sediment transport and have highlighted the importance of coherent flow structures in sediment transport systems. However, the exact mechanisms are still unclear. Furthermore, research in the fluvial environment has identified the significance of turbulent structures for bedform morphology and spacing. However, equivalent research in the aeolian domain is absent. This paper reports the findings of research carried out to characterise the importance of turbulent flow parameters in aeolian sediment transport and determine how turbulent energy and turbulent structures change in response to dune morphology. The relative importance of mean and turbulent wind parameters on aeolian sediment flux was examined in the Skeleton Coast, Namibia. Measurements of wind velocity (using sonic anemometers) and sand transport (using grain impact sensors) at a sampling frequency of 10 Hz were made across a flat surface and along transects on a 9 m high barchan dune. Mean wind parameters and mass sand flux were measured using cup anemometers and wedge-shaped sand traps respectively. Vertical profile data from the sonic anemometers were used to compute turbulence and turbulent stress (Reynolds stress; instantaneous horizontal and vertical fluctuations; coherent flow structures) and their relationship with respect to sand transport and evolving dune morphology. On the flat surface time-averaged parameters generally fail to characterise sand transport dynamics, particularly as the averaging interval is reduced. However, horizontal wind speed correlates well with sand transport even with short averaging times. Quadrant

  17. Numerical simulation of groundwater movement and managed aquifer recharge from Sand Hollow Reservoir, Hurricane Bench area, Washington County, Utah

    Science.gov (United States)

    Marston, Thomas M.; Heilweil, Victor M.

    2012-01-01

    The Hurricane Bench area of Washington County, Utah, is a 70 square-mile area extending south from the Virgin River and encompassing Sand Hollow basin. Sand Hollow Reservoir, located on Hurricane Bench, was completed in March 2002 and is operated primarily as a managed aquifer recharge project by the Washington County Water Conservancy District. The reservoir is situated on a thick sequence of the Navajo Sandstone and Kayenta Formation. Total recharge to the underlying Navajo aquifer from the reservoir was about 86,000 acre-feet from 2002 to 2009. Natural recharge as infiltration of precipitation was approximately 2,100 acre-feet per year for the same period. Discharge occurs as seepage to the Virgin River, municipal and irrigation well withdrawals, and seepage to drains at the base of reservoir dams. Within the Hurricane Bench area, unconfined groundwater-flow conditions generally exist throughout the Navajo Sandstone. Navajo Sandstone hydraulic-conductivity values from regional aquifer testing range from 0.8 to 32 feet per day. The large variability in hydraulic conductivity is attributed to bedrock fractures that trend north-northeast across the study area.A numerical groundwater-flow model was developed to simulate groundwater movement in the Hurricane Bench area and to simulate the movement of managed aquifer recharge from Sand Hollow Reservoir through the groundwater system. The model was calibrated to combined steady- and transient-state conditions. The steady-state portion of the simulation was developed and calibrated by using hydrologic data that represented average conditions for 1975. The transient-state portion of the simulation was developed and calibrated by using hydrologic data collected from 1976 to 2009. Areally, the model grid was 98 rows by 76 columns with a variable cell size ranging from about 1.5 to 25 acres. Smaller cells were used to represent the reservoir to accurately simulate the reservoir bathymetry and nearby monitoring wells; larger

  18. Formulating Fine to Medium Sand Erosion for Suspended Sediment Transport Models

    Directory of Open Access Journals (Sweden)

    François Dufois

    2015-08-01

    Full Text Available The capacity of an advection/diffusion model to predict sand transport under varying wave and current conditions is evaluated. The horizontal sand transport rate is computed by vertical integration of the suspended sediment flux. A correction procedure for the near-bed concentration is proposed so that model results are independent of the vertical resolution. The method can thus be implemented in regional models with operational applications. Simulating equilibrium sand transport rates, when erosion and deposition are balanced, requires a new empirical erosion law that involves the non-dimensional excess shear stress and a parameter that depends on the size of the sand grain. Comparison with several datasets and sediment transport formulae demonstrated the model’s capacity to simulate sand transport rates for a large range of current and wave conditions and sand diameters in the range 100–500 μm. Measured transport rates were predicted within a factor two in 67% of cases with current only and in 35% of cases with both waves and current. In comparison with the results obtained by Camenen and Larroudé (2003, who provided the same indicators for several practical transport rate formulations (whose means are respectively 72% and 37%, the proposed approach gives reasonable results. Before fitting a new erosion law to our model, classical erosion rate formulations were tested but led to poor comparisons with expected sediment transport rates. We suggest that classical erosion laws should be used with care in advection/diffusion models similar to ours, and that at least a full validation procedure for transport rates involving a range of sand diameters and hydrodynamic conditions should be carried out.

  19. SIMULATION OF SEDIMENT TRANSPORT IN THE JEZIORO KOWALSKIE RESERVOIR LOCATED IN THE GLOWNA RIVER

    Directory of Open Access Journals (Sweden)

    Joanna Jaskuła

    2015-07-01

    Full Text Available The purpose of the presented research is the analysis of bed elevation changes caused by sediment accumulation in the Jezioro Kowalskie reservoir. The Jezioro Kowalskie reservoir is a two stage reservoir constructed in such a way that the upper preliminary zone is separated from the main part of the reservoir. The split of the reservoir parts is done with a small pre-dam, located in Jerzykowo town. The analysis of such a construction impact on changes of bed elevations in the reservoir in different flow conditions is presented. The HEC-RAS 5.0 Beta model is used for simulations. The sediment transport intensity is calculated from England-Hansen and Meyer-Peter and Muller formulae. The results showed the processes of sediment accumulation and slight erosion occuring in the preliminary zone of the reservoir. The choice of the flow intensity does not have a huge importance. Similar results are obtained for low as well as high flows. The results confirm, that two stage construction with separated preliminary zone is effective method preventing from the sedimentation of the reservoir.

  20. Sedimentation in Rio La Venta Canyon in Netzahualcoyotl Reservoir, Chiapas, Mexico

    Science.gov (United States)

    Juan Antonio de la Fuente; Tom Lisle; Jose Velasquez; Bonnie L. Allison; Alisha Miller

    2000-01-01

    Sedimentation of Rio La Venta as it enters the Netzahualcoyotl Reservoir in Chiapas, Mexico, threatens a unique part of the aquatic ecosystem. Rio La Venta enters the reservoir via a narrow canyon about 16 km long with spectacular, near-vertical limestone bluffs up to 320 m high and inhabited by the flora and fauna of a pristine tropical forest.

  1. Examination of dam induced sedimentation of small reservoir near Brennbergbánya

    Science.gov (United States)

    Csáfordi, P.; Kalicz, P.; Gribovszki, Z.; Kucsara, M.

    2009-04-01

    The dams' affects on the stream system also involve accelerated sedimentation of reservoirs, change of water and sediment regime. In consequence of sedimentation the lifetime and the recreational potential of reservoirs decrease and management practices have to be applied. The area of our study is a small forested catchment, where the erosion of forested land and the sedimentation of Brennberg Reservoir were investigated in relationship with each other. The Brennberg Reservoir has been built in 1981. It has been silting up forcefully since that time. It has to be dredged with hydraulic earth-moving to preserve its landscape-aesthetical function for the future. We have surveyed the surface to establish the rate of sedimentation. The results of this measurement were processed with a GIS software (named Digiterra Map). There were several uncertainties during our surveying in the field. Therefore three other methods were applied based on GIS and a simply mathematical calculation. The amount of deposited sediment was determined with these methods. Then we compared the results to each other. The annual specific soil loss was estimated according to results of our measurement. Keywords: dam impact, reservoir sedimentation, GIS

  2. Micromechanical investigation of sand migration in gas hydrate-bearing sediments

    Science.gov (United States)

    Uchida, S.; Klar, A.; Cohen, E.

    2017-12-01

    Past field gas production tests from hydrate bearing sediments have indicated that sand migration is an important phenomenon that needs to be considered for successful long-term gas production. The authors previously developed the continuum based analytical thermo-hydro-mechanical sand migration model that can be applied to predict wellbore responses during gas production. However, the model parameters involved in the model still needs to be calibrated and studied thoroughly and it still remains a challenge to conduct well-defined laboratory experiments of sand migration, especially in hydrate-bearing sediments. Taking the advantage of capability of micromechanical modelling approach through discrete element method (DEM), this work presents a first step towards quantifying one of the model parameters that governs stresses reduction due to grain detachment. Grains represented by DEM particles are randomly removed from an isotropically loaded DEM specimen and statistical analyses reveal that linear proportionality exists between the normalized volume of detached solids and normalized reduced stresses. The DEM specimen with different porosities (different packing densities) are also considered and statistical analyses show that there is a clear transition between loose sand behavior and dense sand behavior, characterized by the relative density.

  3. Pore-scale mechanisms of gas flow in tight sand reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Silin, D.; Kneafsey, T.J.; Ajo-Franklin, J.B.; Nico, P.

    2010-11-30

    Tight gas sands are unconventional hydrocarbon energy resource storing large volume of natural gas. Microscopy and 3D imaging of reservoir samples at different scales and resolutions provide insights into the coaredo not significantly smaller in size than conventional sandstones, the extremely dense grain packing makes the pore space tortuous, and the porosity is small. In some cases the inter-granular void space is presented by micron-scale slits, whose geometry requires imaging at submicron resolutions. Maximal Inscribed Spheres computations simulate different scenarios of capillary-equilibrium two-phase fluid displacement. For tight sands, the simulations predict an unusually low wetting fluid saturation threshold, at which the non-wetting phase becomes disconnected. Flow simulations in combination with Maximal Inscribed Spheres computations evaluate relative permeability curves. The computations show that at the threshold saturation, when the nonwetting fluid becomes disconnected, the flow of both fluids is practically blocked. The nonwetting phase is immobile due to the disconnectedness, while the permeability to the wetting phase remains essentially equal to zero due to the pore space geometry. This observation explains the Permeability Jail, which was defined earlier by others. The gas is trapped by capillarity, and the brine is immobile due to the dynamic effects. At the same time, in drainage, simulations predict that the mobility of at least one of the fluids is greater than zero at all saturations. A pore-scale model of gas condensate dropout predicts the rate to be proportional to the scalar product of the fluid velocity and pressure gradient. The narrowest constriction in the flow path is subject to the highest rate of condensation. The pore-scale model naturally upscales to the Panfilov's Darcy-scale model, which implies that the condensate dropout rate is proportional to the pressure gradient squared. Pressure gradient is the greatest near the

  4. Climate Change Impacts on Sediment Quality of Subalpine Reservoirs: Implications on Management

    Directory of Open Access Journals (Sweden)

    Marziali Laura

    2017-09-01

    Full Text Available Reservoirs are characterized by accumulation of sediments where micropollutants may concentrate, with potential toxic effects on downstream river ecosystems. However, sediment management such as flushing is needed to maintain storage capacity. Climate change is expected to increase sediment loads, but potential effects on their quality are scarcely known. In this context, sediment contamination by trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn and organics (Polycyclic Aromatic Hydrocarbons PAHs, Polychlorinated Biphenyls PCBs and C > 12 hydrocarbons was analyzed in 20 reservoirs located in Italian Central Alps. A strong As and a moderate Cd, Hg and Pb enrichment was emphasized by Igeo, with potential ecotoxicological risk according to Probable Effect Concentration quotients. Sedimentation rate, granulometry, total organic carbon (TOC and altitude resulted as the main drivers governing pollutant concentrations in sediments. According to climate change models, expected increase of rainfall erosivity will enhance soil erosion and consequently the sediment flow to reservoirs, potentially increasing coarse grain fractions and thus potentially diluting pollutants. Conversely, increased weathering may enhance metal fluxes to reservoirs. Increased vegetation cover will potentially result in higher TOC concentrations, which may contrast contaminant bioavailability and thus toxicity. Our results may provide elements for a proper management of contaminated sediments in a climate change scenario aiming at preserving water quality and ecosystem functioning.

  5. Influence of break structures on the distribution of radionuclides in bottom sediments of the Kyiv reservoir

    International Nuclear Information System (INIS)

    Shestopalov, V.M.; Lyal'ko, V.I.; Fedorovskij, A.D.; Sirenko, L.A.; Khodorovskij, A.Ya.

    2000-01-01

    We study the distribution of radionuclides in bottom sediments of the Kyiv reservoir on the basis of research of adjacent territory break - block structures with deciphering space-born images and ground measurements and forecast the occurrence of extreme situations due to the redistribution of bottom water flows and sediments of radionuclides

  6. An Integrated Rock Typing Approach for Unraveling the Reservoir Heterogeneity of Tight Sands in the Whicher Range Field of Perth Basin, Western Australia

    DEFF Research Database (Denmark)

    Ilkhchi, Rahim Kadkhodaie; Rezaee, Reza; Harami, Reza Moussavi

    2014-01-01

    Tight gas sands in Whicher Range Field of Perth Basin show large heterogeneity in reservoir characteristics and production behavior related to depositional and diagenetic features. Diagenetic events (compaction and cementation) have severely affected the pore system. In order to investigate...... the petrophysical characteristics, reservoir sandstone facies were correlated with core porosity and permeability and their equivalent well log responses to describe hydraulic flow units and electrofacies, respectively. Thus, very tight, tight, and sub-tight sands were differentiated. To reveal the relationship...... between pore system properties and depositional and diagenetic characteristics in each sand type, reservoir rock types were extracted. The identified reservoir rock types are in fact a reflection of internal reservoir heterogeneity related to pore system properties. All reservoir rock types...

  7. Element Geochemical Analysis of the Contribution of Aeolian Sand to Suspended Sediment in Desert Stream Flash Floods

    Directory of Open Access Journals (Sweden)

    Xiaopeng Jia

    2014-01-01

    Full Text Available The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

  8. Element geochemical analysis of the contribution of aeolian sand to suspended sediment in desert stream flash floods.

    Science.gov (United States)

    Jia, Xiaopeng; Wang, Haibing

    2014-01-01

    The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

  9. Evaluation of suspended sediment concentrations, sediment fluxes and sediment depositions along a reservoir by using laser diffraction and acoustic backscatter data

    Science.gov (United States)

    Lizano, Laura; Haun, Stefan

    2015-04-01

    The construction of dams and reservoirs disturb the natural morphological behavior of rivers. A natural settling effect occurs due to the reduced turbulences and flow velocities. As a consequence, reservoirs fill up with sediments which results in a reduction of storage volume, influences the operation of hydropower plants and leads in several cases to flood protection problems. The sediment depositions in reservoirs are standardly evaluated by using bathymetric data, obtained by a single beam sonar from pre-defined cross sections or by an extensive evaluation of the reservoir bed by a side scan sonar. However, a disadvantage of this method is that it is not possible to evaluate the pore water content of the depositions, which may lead as consequence to an uncertainty in the measured amount of deposited sediments. Given that a major part of sediments entering reservoirs are transported in suspension, sediment flux measurements along defined transects could give more reliable information on the settled amount of sediments and additional information on the sediment transport mechanism within the reservoir. An evaluation of the sediment fluxes is in practice often conducted by a single suspended sediment concentration (SSC) measurement in combination with a cross sectional calibration factor to take changes in the SSC along the transect into account. However, these calibration factors are often developed only for one specific in-situ condition and may give unreliable results in case that the boundaries change e.g. the hydraulic conditions. Hence an evaluation of the sediment fluxes along the whole transect would give a more reliable number for the amount of transported sediments through the reservoir. This information can afterwards be used to calculate the amount of settled sediments in different sections of the reservoir and the amount of sediments which will enter the intake. For this study the suspended sediment transport within the Peñas Blancas reservoir in

  10. Tidal River Elbe - a sediment budget for the grain size fraction of medium sand

    Science.gov (United States)

    Winterscheid, Axel

    2016-04-01

    Human interventions have a historic and ongoing impact on estuarine sediment budgets across many estuaries worldwide. An early inference was the construction of embankments resulting in a constant loss of intertidal flats. Additionally, settlement activities and large scale land use changes in the upstream catchment areas had also an effect on sediment inflow rates. Today, the navigation channels in estuaries have been deepened for larger and more efficient vessels to reach a well-developed infrastructure of harbors and industrial areas often located far inland. In the past few years and just within the North-East Atlantic, the total annual amount of dredged sediments dumped at sea varied from 80 to 130 million tons (OSPAR Commission). In most estuaries across Europe the resulting human impact on the sediment fluxes and morphodynamics is significant. A good understanding of estuarine processes is essential for determining useful and meaningful measures to mitigate negative effects and to improve the current situation. Maintenance dredging and its environmental effects are therefore in the focus of public attention. Against this background, it is the aim of the presentation to identify and therefore to separate the particular effect that maintenance dredging has on sediment fluxes and budgets in the estuarine environment. Case study is the Tidal River Elbe in Germany, and here we set the focus on the grain size fraction of medium sand. In the past, river engineering measures forced the natural dynamics to form a concentrated stream flow along a fixed channel, except at a number of locations where side channels still exist. In addition to that, the main channel was deepened several times. The last deepening was in 1999/2000. The most significant deepening, however, took place from 1957 to 1962. Until then, an erosion-stable layer of marine clay (in German called "Klei") formed a flat bottom along most sections of the main channel. After removal of this layer of

  11. Methodology for Analyzing and Predicting the Runoff and Sediment into a Reservoir

    Directory of Open Access Journals (Sweden)

    Chun-Feng Hao

    2017-06-01

    Full Text Available With the rapid economic growth in China, a large number of hydropower projects have been planned and constructed. The sediment deposition of the reservoirs is one of the most important disputes during the construction and operation, because there are many heavy sediment-laden rivers. The analysis and prediction of the runoff and sediment into a reservoir is of great significance for reservoir operation. With knowledge of the incoming runoff and sediment characteristics, the regulator can adjust the reservoir discharge to guarantee the water supply, and flush more sediment at appropriate times. In this study, the long-term characteristics of runoff and sediment, including trend, jump point, and change cycle, are analyzed using various statistical approaches, such as accumulated anomaly analysis, the Fisher ordered clustering method, and Maximum Entropy Spectral Analysis (MESA. Based on the characteristics, a prediction model is established using the Auto-Regressive Moving Average (ARIMA method. The whole analysis and prediction system is applied to The Three Gorges Project (TGP, one of the biggest hydropower-complex projects in the world. Taking hydrologic series from 1955 to 2010 as the research objectives, the results show that both the runoff and the sediment are decreasing, and the reduction rate of sediment is much higher. Runoff and sediment into the TGP display cyclic variations over time, with a cycle of about a decade, but catastrophe points for runoff and sediment appear in 1991 and 2001, respectively. Prediction models are thus built based on monthly average hydrologic series from 2003 to 2010. ARIMA (1, 1, 1 × (1, 1, 112 and ARIMA (0, 1, 1 × (0, 1, 112 are selected for the runoff and sediment predictions, respectively, and the parameters of the models are also calibrated. The analysis of autocorrelation coefficients and partial autocorrelation coefficients of the residuals indicates that the models built in this study are feasible

  12. Integrated petrophysical approach for determining reserves and reservoir characterization to optimize production of oil sands in northeastern Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, A.; Koch, J. [Weatherford Canada Partnership, Bonneyville, AB (Canada)

    2008-10-15

    This study used logging data, borehole imaging data, dipole sonic and magnetic resonance data to study a set of 6 wells in the McMurray Formation of northeastern Alberta. The data sets were used to understand the geologic settings, fluid properties, and rock properties of the area's geology as well as to more accurately estimate its reservoir and production potential. The study also incorporated data from electric, nuclear and acoustic measurements. A shaly sand analysis was used to provide key reservoir petrophysical data. Image data in the study was used to characterize the heterogeneity and permeability of the reservoir in order to optimize production. Results of the shaly sand analysis were then combined with core data and nuclear resonance data in order to determine permeability and lithology-independent porosity. Data sets were used to iteratively refine an integrated petrophysical analysis. Results of the analysis indicated that the depositional environment in which the wells were located did not match a typical fluvial-estuarine sands environment. A further interpretation of all data indicated that the wells were located in a shoreface environment. It was concluded that the integration of petrophysical measurements can enable geoscientists to more accurately characterize sub-surface environments. 3 refs., 7 figs.

  13. Multielemental characterization of sediments from rivers and reservoirs of a sediment quality monitoring network of Sao Paulo state, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Walace A.A.; Quinaglia, Gilson A., E-mail: wasoares@sp.gov.br, E-mail: gquinaglia@sp.gov.br [Companhia Ambiental do Estado de Sao Paulo (CETESB), SP (Brazil). Setor de Analises Toxicologicas; Favaro, Deborah I.T., E-mail: defavaro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (LAN/CRPq/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica

    2013-07-01

    The Environment Company of the State of Sao Paulo (CETESB) by means of its quality monitoring network does, systematically, the assessment of water and sediment quality in rivers and reservoirs in the Sao Paulo state. The quality evaluation is done by means 50 parameters in water and 63 for sediment that are considered the more representative for CETESB monitoring. In 2011 the network monitoring analyzed 420 points being 24 in sediments. In the present study the multielemental characterization (total concentration) of 13 sediment samples from 24 rivers and reservoirs belonging to the CETESB monitoring network were analyzed by instrumental neutron activation analysis (INAA). The analytical validation according to precision and accuracy was checked through certified reference materials analyzes BEN (Basalt-IWG-GIT), SL-1 (Lake Sediment - IAEA) and Soil-5 (IAEA), that presents certified concentration values for all elements analyzed. The results obtained for multielemental characterization were compared to NASC values (North American Shale Composite) and the enrichment factor (EF) by using Sc as a normalizer element was calculated. The results showed higher enrichment values for As, Br, Cr, Hf, Ta, Th , U and Zn and rare earth elements (REE) Ce, Eu, La, Nd, Sm, Tb and Yb in many of the tested sediment samples indicating that there may be an anthropogenic contribution for these elements. The multielemental results were also compared to the granulometric composition of the sediment samples. Factorial and Cluster Analysis were applied and indicated that the elements distribution is controlled, mainly by the granulometric fractions of the sediments. (author)

  14. Multielemental characterization of sediments from rivers and reservoirs of a sediment quality monitoring network of Sao Paulo state, Brazil

    International Nuclear Information System (INIS)

    Soares, Walace A.A.; Quinaglia, Gilson A.; Favaro, Deborah I.T.

    2013-01-01

    The Environment Company of the State of Sao Paulo (CETESB) by means of its quality monitoring network does, systematically, the assessment of water and sediment quality in rivers and reservoirs in the Sao Paulo state. The quality evaluation is done by means 50 parameters in water and 63 for sediment that are considered the more representative for CETESB monitoring. In 2011 the network monitoring analyzed 420 points being 24 in sediments. In the present study the multielemental characterization (total concentration) of 13 sediment samples from 24 rivers and reservoirs belonging to the CETESB monitoring network were analyzed by instrumental neutron activation analysis (INAA). The analytical validation according to precision and accuracy was checked through certified reference materials analyzes BEN (Basalt-IWG-GIT), SL-1 (Lake Sediment - IAEA) and Soil-5 (IAEA), that presents certified concentration values for all elements analyzed. The results obtained for multielemental characterization were compared to NASC values (North American Shale Composite) and the enrichment factor (EF) by using Sc as a normalizer element was calculated. The results showed higher enrichment values for As, Br, Cr, Hf, Ta, Th , U and Zn and rare earth elements (REE) Ce, Eu, La, Nd, Sm, Tb and Yb in many of the tested sediment samples indicating that there may be an anthropogenic contribution for these elements. The multielemental results were also compared to the granulometric composition of the sediment samples. Factorial and Cluster Analysis were applied and indicated that the elements distribution is controlled, mainly by the granulometric fractions of the sediments. (author)

  15. Physiological and biochemical responses of small fish exposed to Athabasca oil sands sediment

    International Nuclear Information System (INIS)

    Tetrault, G.R.; Environment Canada, Burlington, ON; McMaster, M.E.; Dixon, D.G.; Parrott, J.L.

    2002-01-01

    A study was conducted to determine the influence of naturally occurring oil sands related compounds on the reproductive function and hepatic responses of fish. Wild fish, both exposed and unexposed to the compounds in question, were collected along with sediments for laboratory testing. The study showed that in vitro gonadal incubation levels of steroid production were lower at the tributary sites within the oil sands deposits. One indicator of exposure to oil sands related compounds (hepatic 7-ethoxyresorufin-O-deethylase activity) was shown to be 5 times higher at the same sites. In addition, slimy sculpin were exposed to sediment samples from the Steepbank River site for 4 to 8 days to evaluate the absorption of the indicator. The indicator in exposed fish was found to be comparable to that measured in fish native to the oil sands area. The study was not capable of predicting an altered ability of gonadal tissue of exposed fish to produce steroid hormones in vitro. It was concluded that future development could compromise the reproductive health of fish in the area

  16. Sedimentation control in the reservoirs by using an obstacle

    Indian Academy of Sciences (India)

    2Faculty of Water Sciences Engineering, Shahid Chamran University, Ahwaz, Iran. 3Department of ... some experiments were carried out without an obstacle. Results showed ..... Design and management of dams, reservoirs and watersheds ...

  17. Adsorption of petroleum resins and asphaltenes onto reservoir rock sands studied by near infrared (NIR) spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Syunyaev, R.Z.; Balabin, R.M. [Russian State Univ. of Oil and Gas, Moscow (Russian Federation). Dept. of Physics; Akhatov, I.S. [North Dakota State Univ., Fargo, ND (United States). Dept. of Mechanical Engineering and Center for Nanoscale Science and Engineering

    2008-07-01

    The presence of asphaltene and resin in crude oil is known to cause well bore plugging and pipeline deposition; stabilization of water/oil emulsions; sedimentation and plugging during crude oil storage; adsorption on refining equipment and coke formation. Kinetic and thermodynamic parameters of adsorption are also known to influence wettability and the capillary number. In this study, adsorption parameters of petroleum resins and asphaltenes were evaluated by Near Infrared (NIR) spectroscopy. Fractioned quartz, dolomite, mica and kaolinite sands were used as adsorbent. The particle size distribution was evaluated using an optical microscope. Porosity and permeability of each fraction were designed and benzene was used as the solvent. Various approaches for calibrating NIR spectra-macromolecules concentration were discussed. In this study, the partial least squares (PLS) regression method was used and the Langmuir model was chosen for experimental data fitting. Kinetic and isothermic data was used to evaluate the maximal adsorbed mass density, the equilibrium constant of adsorption, and the rate constants of adsorption and desorption. The rate constants of resins adsorption and desorption depended on the concentration. A numerical algorithm was developed to estimate the diffusion coefficient and relaxation time from the experimental data.

  18. The importance of sand in the formation of avulsion channels within experimental fans that develop from sediment mixtures of mud and sand

    Science.gov (United States)

    Iscen, N.; Strom, K.

    2017-12-01

    Autogenic channel migration and avulsion has long been recognized as important drivers of alluvial fan dynamics. In the literature, several field studies have documented that the presence and the amount of sand transport through a channel is important for channel incision in alluvial fans and deltas. In our experiments, we present the general autogenic avulsion cycle of experimental alluvial fans with mixtures of cohesive sediment and sand with a range of boundary conditions, and we detail the importance of mobile sand fraction in the development of channels that lead to avulsion. Experimental observations demonstrate that new channels form at topographically low regions within the floodplain providing that sand is transported to these topographic lows due to overbank flow or levee breaching. In addition to the sediment transported from upstream, erosion of a previous deposit and an ongoing backfilling nearby are observed as the possible sources of sand getting into the ghost channels. We explore whether the presence of sand is important for channel development because it increases abrasion of the channel or because it changes the roughness characteristics of the flow. We also examine the affect of sediment and water supply change on the newly described channelization process and link distinctive channel morphologies to different stages of described channel development and the avulsion process.

  19. Simulation of Sediment and Cesium Transport in the Ukedo River and the Ogi Dam Reservoir during a Rainfall Event using the TODAM Code

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Yasuo; Yokuda, Satoru T.; Kurikami, Hiroshi

    2014-03-28

    The accident at the Fukushima Daiichi Nuclear Power Plant in March 2011 caused widespread environmental contamination. Although decontamination activities have been performed in residential areas of the Fukushima area, decontamination of forests, rivers, and reservoirs is still controversial because of the economical, ecological, and technical difficulties. Thus, an evaluation of contaminant transport in such an environment is important for safety assessment and for implementation of possible countermeasures to reduce radiation exposure to the public. The investigation revealed that heavy rainfall events play a significant role in transporting radioactive cesium deposited on the land surface, via soil erosion and sediment transport in rivers. Therefore, we simulated the sediment and cesium transport in the Ukedo River and its tributaries in Fukushima Prefecture, including the Ogaki Dam Reservoir, and the Ogi Dam Reservoir of the Oginosawa River in Fukushima Prefecture during and after a heavy rainfall event by using the TODAM (Time-dependent, One-dimensional Degradation And Migration) code. The main outcomes are the following: • Suspended sand is mostly deposited on the river bottom. Suspended silt and clay, on the other hand, are hardly deposited in the Ukedo River and its tributaries except in the Ogaki Dam Reservoir in the Ukedo River even in low river discharge conditions. • Cesium migrates mainly during high river discharge periods during heavy rainfall events. Silt and clay play more important roles in cesium transport to the sea than sand does. • The simulation results explain variations in the field data on cesium distributions in the river. Additional field data currently being collected and further modeling with these data may shed more light on the cesium distribution variations. • Effects of 40-hour heavy rainfall events on clay and cesium transport continue for more than a month. This is because these reservoirs slow down the storm-induced high

  20. A Visual Basic program to classify sediments based on gravel-sand-silt-clay ratios

    Science.gov (United States)

    Poppe, L.J.; Eliason, A.H.; Hastings, M.E.

    2003-01-01

    Nomenclature describing size distributions is important to geologists because grain size is the most basic attribute of sediments. Traditionally, geologists have divided sediments into four size fractions that include gravel, sand, silt, and clay, and classified these sediments based on ratios of the various proportions of the fractions. Definitions of these fractions have long been standardized to the grade scale described by Wentworth (1922), and two main classification schemes have been adopted to describe the approximate relationship between the size fractions.Specifically, according to the Wentworth grade scale gravel-sized particles have a nominal diameter of ⩾2.0 mm; sand-sized particles have nominal diameters from <2.0 mm to ⩾62.5 μm; silt-sized particles have nominal diameters from <62.5 to ⩾4.0 μm; and clay is <4.0 μm. As for sediment classification, most sedimentologists use one of the systems described either by Shepard (1954) or Folk (1954, 1974). The original scheme devised by Shepard (1954) utilized a single ternary diagram with sand, silt, and clay in the corners to graphically show the relative proportions among these three grades within a sample. This scheme, however, does not allow for sediments with significant amounts of gravel. Therefore, Shepard's classification scheme (Fig. 1) was subsequently modified by the addition of a second ternary diagram to account for the gravel fraction (Schlee, 1973). The system devised by Folk (1954, 1974) is also based on two triangular diagrams (Fig. 2), but it has 23 major categories, and uses the term mud (defined as silt plus clay). The patterns within the triangles of both systems differ, as does the emphasis placed on gravel. For example, in the system described by Shepard, gravelly sediments have more than 10% gravel; in Folk's system, slightly gravelly sediments have as little as 0.01% gravel. Folk's classification scheme stresses gravel because its concentration is a function of

  1. Background Radioactivity in River and Reservoir Sediments near Los Alamos, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    S.G.McLin; D.W. Lyons

    2002-05-05

    As part of its continuing Environmental Surveillance Program, regional river and lake-bottom sediments have been collected annually by Los Alamos National Laboratory (the Laboratory) since 1974 and 1979, respectively. These background samples are collected from three drainage basins at ten different river stations and five reservoirs located throughout northern New Mexico and southern Colorado. Radiochemical analyses for these sediments include tritium, strontium-90, cesium-137, total uranium, plutonium-238, plutonium-239,-240, americium-241, gross alpha, gross beta, and gross gamma radioactivity. Detection-limit radioactivity originates as worldwide fallout from aboveground nuclear weapons testing and satellite reentry into Earth's atmosphere. Spatial and temporal variations in individual analyte levels originate from atmospheric point-source introductions and natural rate differences in airborne deposition and soil erosion. Background radioactivity values on sediments reflect this variability, and grouped river and reservoir sediment samples show a range of statistical distributions that appear to be analyte dependent. Traditionally, both river and reservoir analyte data were blended together to establish background levels. In this report, however, we group background sediment data according to two criteria. These include sediment source (either river or reservoir sediments) and station location relative to the Laboratory (either upstream or downstream). These grouped data are statistically evaluated through 1997, and background radioactivity values are established for individual analytes in upstream river and reservoir sediments. This information may be used to establish the existence and areal extent of trace-level environmental contamination resulting from historical Laboratory research activities since the early 1940s.

  2. Gravel-Sand-Clay Mixture Model for Predictions of Permeability and Velocity of Unconsolidated Sediments

    Science.gov (United States)

    Konishi, C.

    2014-12-01

    Gravel-sand-clay mixture model is proposed particularly for unconsolidated sediments to predict permeability and velocity from volume fractions of the three components (i.e. gravel, sand, and clay). A well-known sand-clay mixture model or bimodal mixture model treats clay contents as volume fraction of the small particle and the rest of the volume is considered as that of the large particle. This simple approach has been commonly accepted and has validated by many studies before. However, a collection of laboratory measurements of permeability and grain size distribution for unconsolidated samples show an impact of presence of another large particle; i.e. only a few percent of gravel particles increases the permeability of the sample significantly. This observation cannot be explained by the bimodal mixture model and it suggests the necessity of considering the gravel-sand-clay mixture model. In the proposed model, I consider the three volume fractions of each component instead of using only the clay contents. Sand becomes either larger or smaller particles in the three component mixture model, whereas it is always the large particle in the bimodal mixture model. The total porosity of the two cases, one is the case that the sand is smaller particle and the other is the case that the sand is larger particle, can be modeled independently from sand volume fraction by the same fashion in the bimodal model. However, the two cases can co-exist in one sample; thus, the total porosity of the mixed sample is calculated by weighted average of the two cases by the volume fractions of gravel and clay. The effective porosity is distinguished from the total porosity assuming that the porosity associated with clay is zero effective porosity. In addition, effective grain size can be computed from the volume fractions and representative grain sizes for each component. Using the effective porosity and the effective grain size, the permeability is predicted by Kozeny-Carman equation

  3. Bedform Dimensions and Suspended Sediment Observations in a Mixed Sand-Mud Intertidal Environment

    Science.gov (United States)

    Lichtman, I. D.; Amoudry, L.; Peter, T.; Jaco, B.

    2016-02-01

    Small-scale bedforms, such as ripples, can profoundly modify near-bed hydrodynamics, near-bed sediment transport and resuspension, and benthic-pelagic fluxes. Knowledge of their dimensions is important for a number of applications. Fundamentally different processes can occur depending on the dimensions of ripples: for low and long ripples, the bed remains dynamically flat and diffusive processes dominate sediment entrainment; for steep ripples, flow separation occurs above the ripples creating vortices, which are far more efficient at entraining sediment into the water column. Recent laboratory experiments for mixtures of sand and mud have shown that bedform dimensions decrease with increasing sediment mud content. However, these same experiments also showed that mud is selectively taken into suspension when bedforms are created and migrate on the bed, leaving sandy bedforms. This entrainment process, selectively suspending fine sediment, is referred to as winnowing. To improve our understanding of bedform and entrainment dynamics of mixed sediments, in situ observations were made on intertidal flats in the Dee Estuary, United Kingdom. A suite of instruments were deployed collecting co-located measurements of the near-bed hydrodynamics, waves, small-scale bed morphology and suspended sediment. Three sites were occupied consecutively, over a Spring-Neap cycle, collecting data for different bed compositions, tide levels and wind conditions. Bed samples were taken when the flats became exposed at low water and a sediment trap collected suspended load when inundated. This study will combine these measurements to investigate the interactions between small-scale bed morphology, near-bed hydrodynamics and sediment entrainment. We will examine bedform development in the complex hydrodynamic and wave climate of tidal flats, in relation to standard ripple predictors. We will also relate the variability in small-scale bedforms to variation in hydrodynamic and wave conditions

  4. Nitrogen and phosphorus in cascade multi-system tropical reservoirs: water and sediment

    Directory of Open Access Journals (Sweden)

    Pompêo Marcelo

    2017-09-01

    Full Text Available The aim of this research was to analyze the horizontal spatial heterogeneity of both water and superficial sediment quality among and within the reservoirs of the Cantareira System (CS, focusing on concentrations of N and P, attributed to the dumping of raw domestic sewage into water bodies, which is the main cause of water pollution in São Paulo State (Brazil. The CS is a multi-system complex composed of five interconnected reservoirs, with water transported by gravity through 48 km of tunnels and channels. From the last reservoir of the CS, with an output of 33 m3 s−1, the water is conducted to a water treatment plant, producing half of the water consumed by 19 million people inhabiting São Paulo city. The upstream reservoirs are more eutrophic than the downstream ones. Data also suggest that the low phytoplankton biomass (ranging from 0.9 to 14.4 μg dm−3 is regulated by the low nutrient availability, mainly of phosphorus (TP ranging from below the detection limit, <9.0 μg dm−3, to 47.3 μg dm−3. For water, the DIN/TP ratios values range from 19 to 380. The upstream reservoirs function as nutrient accumulators and the sediment is the main compartment in which P and N are stored. Although the reservoirs are located in different river basins and are not in sequence along the same river, the results suggest a marked gradient between the reservoirs, with features similar to those of cascade reservoirs. The large volumes flowing through the canals and tunnels could explain the observed pattern. The CS reservoirs can therefore be considered multi-system reservoirs in cascade, constituting a particular case of multi-system reservoirs.

  5. Andean cutaneous leishmaniasis (Andean-CL, uta) in Peru and Ecuador: the vector Lutzomyia sand flies and reservoir mammals.

    Science.gov (United States)

    Hashiguchi, Yoshihisa; Gomez L, Eduardo A; Cáceres, Abraham G; Velez, Lenin N; Villegas, Nancy V; Hashiguchi, Kazue; Mimori, Tatsuyuki; Uezato, Hiroshi; Kato, Hirotomo

    2018-02-01

    The vector Lutzomyia sand flies and reservoir host mammals of the Leishmania parasites, causing the Andean cutaneous leishmaniasis (Andean-CL, uta) in Peru and Ecuador were thoroughly reviewed, performing a survey of literatures including our unpublished data. The Peruvian L. (V.) peruviana, a principal Leishmania species causing Andean-CL in Peru, possessed three Lutzomyia species, Lu. peruensis, Lu. verrucarum and Lu. ayacuchensis as vectors, while the Ecuadorian L. (L.) mexicana parasite possessed only one species Lu. ayacuchensis as the vector. Among these, the Ecuadorian showed a markedly higher rate of natural Leishmania infections. However, the monthly and diurnal biting activities were mostly similar among these vector species was in both countries, and the higher rates of infection (transmission) reported, corresponded to sand fly's higher monthly-activity season (rainy season). The Lu. tejadai sand fly participated as a vector of a hybrid parasite of L. (V.) braziliensis/L. (V.) peruviana in the Peruvian Andes. Dogs were considered to be principal reservoir hosts of the L. (V.) peruviana and L. (L.) mexicana parasites in both countries, followed by other sylvatic mammals such as Phyllotis andium, Didelphis albiventris and Akodon sp. in Peru, and Rattus rattus in Ecuador, but information on the reservoir hosts/mammals was extremely poor in both countries. Thus, the Peruvian disease form demonstrated more complicated transmission dynamics than the Ecuadorian. A brief review was also given to the control of vector and reservoirs in the Andes areas. Such information is crucial for future development of the control strategies of the disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Assessment of managed aquifer recharge at Sand Hollow Reservoir, Washington County, Utah, updated to conditions through 2007

    Science.gov (United States)

    Heilweil, Victor M.; Ortiz, Gema; Susong, David D.

    2009-01-01

    Sand Hollow Reservoir in Washington County, Utah, was completed in March 2002 and is operated primarily as an aquifer storage and recovery project by the Washington County Water Conservancy District (WCWCD). Since its inception in 2002 through 2007, surface-water diversions of about 126,000 acre-feet to Sand Hollow Reservoir have resulted in a generally rising reservoir stage and surface area. Large volumes of runoff during spring 2005-06 allowed the WCWCD to fill the reservoir to a total storage capacity of more than 50,000 acre-feet, with a corresponding surface area of about 1,300 acres and reservoir stage of about 3,060 feet during 2006. During 2007, reservoir stage generally decreased to about 3,040 feet with a surface-water storage volume of about 30,000 acre-feet. Water temperature in the reservoir shows large seasonal variation and has ranged from about 3 to 30 deg C from 2003 through 2007. Except for anomalously high recharge rates during the first year when the vadose zone beneath the reservoir was becoming saturated, estimated ground-water recharge rates have ranged from 0.01 to 0.09 feet per day. Estimated recharge volumes have ranged from about 200 to 3,500 acre-feet per month from March 2002 through December 2007. Total ground-water recharge during the same period is estimated to have been about 69,000 acre-feet. Estimated evaporation rates have varied from 0.04 to 0.97 feet per month, resulting in evaporation losses of 20 to 1,200 acre-feet per month. Total evaporation from March 2002 through December 2007 is estimated to have been about 25,000 acre-feet. Results of water-quality sampling at monitoring wells indicate that by 2007, managed aquifer recharge had arrived at sites 37 and 36, located 60 and 160 feet from the reservoir, respectively. However, different peak arrival dates for specific conductance, chloride, chloride/bromide ratios, dissolved oxygen, and total dissolved-gas pressures at each monitoring well indicate the complicated nature of

  7. Spatial variation of sediment mineralization supports differential CO2 emissions from a tropical hydroelectric reservoir

    Directory of Open Access Journals (Sweden)

    Simone Jaqueline Cardoso

    2013-04-01

    Full Text Available Substantial amounts of organic matter (OM from terrestrial ecosystems are buried as sediments in inland waters. It is still unclear to what extent this OM constitutes a sink of carbon, and how much of it is returned to the atmosphere upon mineralization to carbon dioxide (CO2. The construction of reservoirs affects the carbon cycle by increasing OM sedimentation at the regional scale. In this study we determine the OM mineralization in the sediment of three zones (river, transition and dam of a tropical hydroelectric reservoir in Brazil as well as identify the composition of the carbon pool available for mineralization. We measured sediment OC mineralization rates and related them to the composition of the OM, bacterial abundance and pCO2 of the surface water of the reservoir. Terrestrial OM was an important substrate for the mineralization. In the river and transition zones most of the OM was allochthonous (56 % and 48 %, respectively while the dam zone had the lowest allochthonous contribution (7 %. The highest mineralization rates were found in the transition zone (154.80 ± 33.50 mg C m-2 d-1 and the lowest in the dam (51.60 ± 26.80 mg C m-2 d-1. Moreover, mineralization rates were significantly related to bacterial abundance (r2 = 0.50, p < 0.001 and pCO2 in the surface water of the reservoir (r2 = 0.73, p < 0.001. The results indicate that allochthonous OM has different contributions to sediment mineralization in the three zones of the reservoir. Further, the sediment mineralization, mediated by heterotrophic bacteria metabolism, significantly contributes to CO2 supersaturation in the water column, resulting in higher pCO2 in the river and transition zones in comparison with the dam zone, affecting greenhouse gas emission estimations from hydroelectric reservoirs.

  8. Uranium series isotopes concentration in sediments at San Marcos and Luis L. Leon reservoirs, Chihuahua, Mexico

    Science.gov (United States)

    Méndez-García, C.; Renteria-Villalobos, M.; García-Tenorio, R.; Montero-Cabrera, M. E.

    2014-07-01

    Spatial and temporal distribution of the radioisotopes concentrations were determined in sediments near the surface and core samples extracted from two reservoirs located in an arid region close to Chihuahua City, Mexico. At San Marcos reservoir one core was studied, while from Luis L. Leon reservoir one core from the entrance and another one close to the wall were investigated. 232Th-series, 238U-series, 40K and 137Cs activity concentrations (AC, Bq kg-1) were determined by gamma spectrometry with a high purity Ge detector. 238U and 234U ACs were obtained by liquid scintillation and alpha spectrometry with a surface barrier detector. Dating of core sediments was performed applying CRS method to 210Pb activities. Results were verified by 137Cs AC. Resulting activity concentrations were compared among corresponding surface and core sediments. High 238U-series AC values were found in sediments from San Marcos reservoir, because this site is located close to the Victorino uranium deposit. Low AC values found in Luis L. Leon reservoir suggest that the uranium present in the source of the Sacramento - Chuviscar Rivers is not transported up to the Conchos River. Activity ratios (AR) 234U/overflow="scroll">238U and 238U/overflow="scroll">226Ra in sediments have values between 0.9-1.2, showing a behavior close to radioactive equilibrium in the entire basin. 232Th/overflow="scroll">238U, 228Ra/overflow="scroll">226Ra ARs are witnesses of the different geological origin of sediments from San Marcos and Luis L. Leon reservoirs.

  9. Uranium series isotopes concentration in sediments at San Marcos and Luis L. Leon reservoirs, Chihuahua, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Méndez-García, C.; Montero-Cabrera, M. E., E-mail: elena.montero@cimav.edu.mx [Centro de Investigación en Materiales Avanzados, CIMAV, Miguel de Cervantes 120, 31109, Chihuahua, Chihuahua (Mexico); Renteria-Villalobos, M. [Facultad de Zootecnia y Ecología Universidad Autónoma de Chihuahua, Periferico Francisco R. Almada Km 1, 31410, Chihuahua (Mexico); García-Tenorio, R. [Applied Nuclear Physics Group, University of Seville, ETS Arquitectura, Avda. Reina Mercedes s/n, 41012 Seville (Spain)

    2008-01-01

    Spatial and temporal distribution of the radioisotopes concentrations were determined in sediments near the surface and core samples extracted from two reservoirs located in an arid region close to Chihuahua City, Mexico. At San Marcos reservoir one core was studied, while from Luis L. Leon reservoir one core from the entrance and another one close to the wall were investigated. ²³²Th-series, ²³⁸U-series, ⁴⁰K and ¹³⁷Cs activity concentrations (AC, Bq kg⁻¹) were determined by gamma spectrometry with a high purity Ge detector. ²³⁸U and ²³⁴U ACs were obtained by liquid scintillation and alpha spectrometry with a surface barrier detector. Dating of core sediments was performed applying CRS method to ²¹⁰Pb activities. Results were verified by ¹³⁷Cs AC. Resulting activity concentrations were compared among corresponding surface and core sediments. High ²³⁸U-series AC values were found in sediments from San Marcos reservoir, because this site is located close to the Victorino uranium deposit. Low AC values found in Luis L. Leon reservoir suggest that the uranium present in the source of the Sacramento – Chuviscar Rivers is not transported up to the Conchos River. Activity ratios (AR) ²³⁴U/²³⁸U and ²³⁸U/²²⁶Ra in sediments have values between 0.9–1.2, showing a behavior close to radioactive equilibrium in the entire basin. ²³²Th/²³⁸U, ²²⁸Ra/²²⁶Ra ARs are witnesses of the different geological origin of sediments from San Marcos and Luis L. Leon reservoirs.

  10. Uranium series isotopes concentration in sediments at San Marcos and Luis L. Leon reservoirs, Chihuahua, Mexico

    International Nuclear Information System (INIS)

    Méndez-García, C.; Montero-Cabrera, M. E.; Renteria-Villalobos, M.; García-Tenorio, R.

    2014-01-01

    Spatial and temporal distribution of the radioisotopes concentrations were determined in sediments near the surface and core samples extracted from two reservoirs located in an arid region close to Chihuahua City, Mexico. At San Marcos reservoir one core was studied, while from Luis L. Leon reservoir one core from the entrance and another one close to the wall were investigated. 232 Th-series, 238 U-series, 40 K and 137 Cs activity concentrations (AC, Bq kg −1 ) were determined by gamma spectrometry with a high purity Ge detector. 238 U and 234 U ACs were obtained by liquid scintillation and alpha spectrometry with a surface barrier detector. Dating of core sediments was performed applying CRS method to 210 Pb activities. Results were verified by 137 Cs AC. Resulting activity concentrations were compared among corresponding surface and core sediments. High 238 U-series AC values were found in sediments from San Marcos reservoir, because this site is located close to the Victorino uranium deposit. Low AC values found in Luis L. Leon reservoir suggest that the uranium present in the source of the Sacramento – Chuviscar Rivers is not transported up to the Conchos River. Activity ratios (AR) 234 U/ 238 U and 238 U/ 226 Ra in sediments have values between 0.9–1.2, showing a behavior close to radioactive equilibrium in the entire basin. 232 Th/ 238 U, 228 Ra/ 226 Ra ARs are witnesses of the different geological origin of sediments from San Marcos and Luis L. Leon reservoirs

  11. [Effect of the Runoff-sediment Control of the Xiaolangdi Reservoir on DOC Transport].

    Science.gov (United States)

    Zhang, Yong-ling; Wang, Ming-shi; Dong, Yu-long

    2015-04-01

    The sampling was carried out in Sanmenxia hydrological station, Xiaolangdi hydrological station and Huayuankou hydrological station from November 2011 to October 2012. The impact of the runoff-sediment control of the Xiaolangdi reservoir on DOC transport,was analyzed. The results were as follows. DOC contents in Sanmenxia station, Xiaolangdi station and Huayuankou station were 1.97-2.71 mg-L(-1), 1.87-2.76 mg x L(-1) and 2.07-2.93 mg x L(-1), respectively, during the normal operation period of Xiaolangdi Reservoir and Sanmenxia reservoir, and the DOC content in the three reservoirs had obvious seasonal change. DOC contents in the three stations were 2.14-3.32 mg x L(-1), 2.21-2.84 mg x L(-1) and 2.11-2.84 mg x L(-1), respectively, during the runoff-sediment control, and the DOC content in the sediment-releasing period of reservoir was higher than that in the water-releasing period of reservoir. DOC content had no significant correlation with TSS and flow either during the normal operation or during the water-sediment regulation of the reservoir. But the DOC content had significant correlation with water temperature during the normal operation of the reservoir. DOC flux in Sanmenxia station was similar to that in Xiaolangdi station from November to March. DOC flux in Sanmenxia station was obviously less than that in Xiaolangdi station from April to July. And the DOC flux in Sanmenxia station was much higher than that in Xiaolangdi station from August to October. The result showed that DOC was retained from August to October by Xiaolangdi reservoir and discharged from Xiaolangdi reservoir from April to July. The yearly DOC fluxes were 8.6 x 10(10), 9.0 x 10(10) and 9.7 x 10(10) g respectively in Sanmenxia station, Xiaolangdi station and Huayuankou station. The DOC flux of Sanmenxia station was the highest in September, which accounted for 22.0% of the yearly DOC flux, and the DOC flux of Xiaolangdi station was the highest in June, which accounted for 17.6% of the

  12. Implications of the sedimentation phenomenon in the design of hydropower reservoirs

    International Nuclear Information System (INIS)

    Scvortov, Felix; Armencea, Gheorghe

    1992-01-01

    The influence of sedimentation phenomena on the operational parameters of the hydropower reservoirs built on several Romanian rivers was assessed. A cascade of eight reservoirs on the Olt river, with initial volumes of 20-50 M m 3 , lost about 30% of the conservation capacity and about 3-7% of head as well. Smaller reservoirs, with volumes of 2-10 M m 3 , lost 60-85% of their capacity. Dredging operations had to be done, thus, increasing the initial costs by 20%. The acquired experience revealed that the evolution in time of the reservoir capacity over the operation period should be as accurately as possible taken into account in the designing stage. The operation conditions and designing criterions for small and medium hydropower reservoir have to be reassessed also from the environmental and efficiency points of view. The content of the paper is the following: 1. Sedimentation knowledge and planning concepts for inland rivers; 2. Implications of the sedimentation phenomenon; 3. Forecast of the sedimentation phenomenon; 4. Retrospective and perspective; 5. Conclusions. (authors)

  13. A Study of Sedimentation at the River Estuary on the Change of Reservoir Storage

    OpenAIRE

    Iskahar; Suripin; Isdiyana

    2018-01-01

    Estuary of the river that leads to the reservoir has characteristics include: relatively flat, there is a change in the increase of wet cross-sectional area and backwater. The backwater will cause the flow velocity to be reduced, so that the grains of sediment with a certain diameter carried by the flow will settle in the estuary of the river. The purpose of this research is to know the distribution and sedimentation pattern at the river estuary that leads to the reservoir with the change of ...

  14. Sediment oxygen demand of wetlands in the oil sands region of northeastern Alberta

    International Nuclear Information System (INIS)

    Slama, C.; Gardner Costa, J.; Ciborowski, J.

    2010-01-01

    Sediment oxygen demand (SOD) can significantly influence the dissolved oxygen concentrations in shallow water bodies. This study discussed the types of sediments used to reclaim wetlands and their influence on SOD, successional processes, and ecosystem trajectories. The study hypothesized that oil sands process material (OSPM) affected wetlands would support cyanobacterial biofilms as opposed to submergent macrophytes as a result of insufficient phosphorus levels. SOD was assessed by monitoring dissolved oxygen concentrations within domes placed on the sediment surface for a 3-hour period. Gas flux and composition analyses were used to quantify the biological SOD components. Chemical SOD components were then determined by subtraction. Concentrations of phosphorus bioavailable to the macrophytes were estimated using plant root simulator probes. The study showed that OSPM wetlands exhibited higher chemical SOD and SOD than reference wetlands, and supported benthic biofilms as opposed to the submergent macrophyte communities typically found in northeastern Alberta wetlands.

  15. Sediment oxygen demand of wetlands in the oil sands region of northeastern Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Slama, C.; Gardner Costa, J.; Ciborowski, J. [Windsor Univ., ON (Canada)

    2010-07-01

    Sediment oxygen demand (SOD) can significantly influence the dissolved oxygen concentrations in shallow water bodies. This study discussed the types of sediments used to reclaim wetlands and their influence on SOD, successional processes, and ecosystem trajectories. The study hypothesized that oil sands process material (OSPM) affected wetlands would support cyanobacterial biofilms as opposed to submergent macrophytes as a result of insufficient phosphorus levels. SOD was assessed by monitoring dissolved oxygen concentrations within domes placed on the sediment surface for a 3-hour period. Gas flux and composition analyses were used to quantify the biological SOD components. Chemical SOD components were then determined by subtraction. Concentrations of phosphorus bioavailable to the macrophytes were estimated using plant root simulator probes. The study showed that OSPM wetlands exhibited higher chemical SOD and SOD than reference wetlands, and supported benthic biofilms as opposed to the submergent macrophyte communities typically found in northeastern Alberta wetlands.

  16. Ecological and Control Techniques for Sand Flies (Diptera: Psychodidae) Associated with Rodent Reservoirs of Leishmaniasis

    Science.gov (United States)

    2013-09-12

    that cause visceral or dermal leishmaniasis. Unveiling aspects of the life cycles of sand flies that could be targeted with insecticides would guide...leishmaniasis. Unveiling aspects of the life cycles of sand flies that could be targeted with insecticides would guide future sand fly control programs for...to break the transmission cycle of L. major parasites, similar to what Kobylinski et al. described for reducing Plasmodium infection rates in malaria

  17. Impact of Sedimentation hazard at Jor Reservoir, Batang Padang Hydroelectric Scheme in Malaysia

    Science.gov (United States)

    Luis, Jansen; Mohd Sidek, Lariyah; Jajarmizadeh, Milad

    2016-03-01

    Sedimentation in reservoir can be treated as a hazard because it affects the overall safety of the dam. It is a growing concern for reservoir operators throughout the world as it impacts the operability of the hydropower plant and its function as flood control. The objective of the study is to carry out reservoir bathymetric survey to determine the storage volume available at Jor reservoir. The paper intends to discuss the results of two successive surveys carried out in year 2007 and 2010 and comparison with historical data in1968 owing to analyse of sedimentation trend. The result showed that the total storage loss is approximately 43% with an estimated deposited sediment volume of 1.4 million m3 in year 2010. The sedimentation rate is estimated at 3.3% for the years surveyed which is greater than the world average of 0.93%. The findings from the survey are used to develop a revised elevation-storage curve which could be used by the operator and engineers to carry out future power generation planning and flood study predictions. The findings are also expected to be used to determine the optimum method for sediment management and hydro-mechanical protection.

  18. Preliminary Assessment of Silting and The Quality of Bottom Sediments in A Small Water Reservoir

    Directory of Open Access Journals (Sweden)

    Bąk Łukasz

    2014-07-01

    Full Text Available The aim of this study was to assess the degree of silting and pollution of bottom sediments in a small water reservoir Lubianka situated in Starachowice, Świętokrzyskie Province, with selected heavy metals (Pb, Cr, Cd, Cu, Ni, Zn, Fe, Mn, Hg. Catchment basin of the reservoir is forested in 92%. Other parts are covered by estates of detached houses, barren lands and green areas. Bathymetric measurements and analyses of trace elements in bottom sediments were made in 2012. After 28 years of exploitation, reservoir's basin accumulated 43 thousand cubic metres of sediments i.e. 4.7% of its initial volume. Mean annual silting rate was 0.17%. Due to the content of copper and chromium, bottom sediments were classified to the II category (sediments of average pollution according to geochemical standards. Concentrations of Pb, Cd and Hg in all analysed samples were below geochemical background. In a sample collected at the inlet to the reservoir, the TEL index for chromium was exceeded by 25.6%. In other samples the threshold values of the TEL and PEL indices were not exceeded.

  19. 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.

  20. Ephemeral-fluvial sediments as potential hydrocarbon reservoirs. Vol. 1: Sedimentology

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, K.S.

    1994-12-31

    Although reservoirs formed from ephemeral-fluvial sandstones have previously been considered relatively simple, unresolved problems of sandbody correlation and production anomalies demonstrate the need for improved understanding of their internal complexity. Outcropping ephemeral-fluvial systems have been studied in order to determine the main features and processes occurring in sand-rich ephemeral systems and to identify which features will be of importance in a hydrocarbon reservoir. The Lower Jurassic Upper Moenave and Kayenta Formations of south-eastern Utah and northern Arizona comprise series of stacked, sand-dominated sheet-like palaeochannels suggestive of low sinuosity, braided systems. Low subsidence rates and rapid lateral migration rates enabled channels to significantly modify their widths during high discharge. (author)

  1. A laboratory experiment on the evolution of a sand gravel reach under a lack of sediment supply

    NARCIS (Netherlands)

    Orru, C.; Chavarrias Borras, V.; Ferrara, V.; Stecca, G.; Blom, A.

    2015-01-01

    A flume experiment was conducted to examine the evolution of a sand-gravel reach under a lack of sediment supply. A bed composed of a bimodal sediment mixture was installed with a uniform slope and an gradual fining pattern. At the upstream end of the flume the initial bed consisted of 100% gravel,

  2. Prediction of sand production onset in petroleum reservoirs using a reliable classification approach

    Directory of Open Access Journals (Sweden)

    Farhad Gharagheizi

    2017-06-01

    It is shown that the developed model can accurately predict the sand production in a real field. The results of this study indicates that implementation of LSSVM modeling can effectively help completion designers to make an on time sand control plan with least deterioration of production.

  3. Sediment deposition and trends and transport of phosphorus and other chemical constituents, Cheney Reservoir watershed, south-central Kansas

    Science.gov (United States)

    Mau, D.P.

    2001-01-01

    Sediment deposition, water-quality trends, and mass transport of phosphorus, nitrogen, selected trace elements, and selected pesticides within the Cheney Reservoir watershed in south-central Kansas were investigated using bathymetric survey data and reservoir bottom-sediment cores. Sediment loads in the reservoir were investigated by comparing 1964 topographic data to 1998 bathymetric survey data. Approximately 7,100 acre-feet of sediment deposition occurred in Cheney Reservoir from 1965 through 1998. As of 1998, sediment had filled 27 percent of the reservoir's inactive conservation storage pool, which is less than the design estimate of 34 percent. Mean annual sediment deposition was 209 acre-feet per year, or 0.22 acre-feet per year per square mile, and the mean annual sediment load was 453 million pounds per year. During the 3-year period from 1997 through 1999, 23 sediment cores were collected from the reservoir, and subsamples were analyzed for nutrients (phosphorus and nitrogen species), selected trace elements, and selected organic pesticides. Mean concentrations of total phosphorus in reservoir bottom sediment ranged from 94 milligrams per kilogram at the upstream end of the reservoir to 710 milligrams per kilogram farther downstream near the reservoir dam. The mean concentration for all sites was 480 milligrams per kilogram. Total phosphorus concentrations were greatest when more silt- and clay-sized particles were present. The implications are that if anoxic conditions (inadequate oxygen) occur near the dam, phosphorus could be released from the sediment and affect the drinking-water supply. Analysis of selected cores also indicates that total phosphorus concentrations in the reservoir sediment increased over time and were probably the result of nonpoint-source activities in the watershed, such as increased fertilizer use and livestock production. Mean annual phosphorus loading to Cheney Reservoir was estimated to be 226,000 pounds per year on the basis

  4. Sediment sorting along tidal sand waves: A comparison between field observations and theoretical predictions

    Science.gov (United States)

    Van Oyen, Tomas; Blondeaux, Paolo; Van den Eynde, Dries

    2013-07-01

    A site-by-site comparison between field observations and theoretical predictions of sediment sorting patterns along tidal sand waves is performed for ten locations in the North Sea. At each site, the observed grain size distribution along the bottom topography and the geometry of the bed forms is described in detail and the procedure used to obtain the model parameters is summarized. The model appears to accurately describe the wavelength of the observed sand waves for the majority of the locations; still providing a reliable estimate for the other sites. In addition, it is found that for seven out of the ten locations, the qualitative sorting process provided by the model agrees with the observed grain size distribution. A discussion of the site-by-site comparison is provided which, taking into account uncertainties in the field data, indicates that the model grasps the major part of the key processes controlling the phenomenon.

  5. Sediment accumulation and water volume in Loch Raven Reservoir, Baltimore County, Maryland

    Science.gov (United States)

    Banks, William S.L.; LaMotte, Andrew E.

    1999-01-01

    Baltimore City and its metropolitan area are supplied with water from three reservoirs, Liberty Reservoir, Prettyboy Reservoir, and Loch Raven Reservoir. Prettyboy and Loch Raven Reservoirs are located on the Gunpowder Falls (figure 1). The many uses of the reservoir system necessitate coordination and communication among resource managers. The 1996 Amendment to the Safe Drinking Water Act require States to complete source-water assessments for public drinking-water supplies. As part of an ongoing effort to provide safe drinking water and as a direct result of these laws, the City of Baltimore and the Maryland Department of the Environment (MDE), in cooperation with other State and local agencies, are studying the Gunpowder Falls Basin and its role as a source of water supply to the Baltimore area. As a part of this study, the U.S. Geological Survey (USGS), in cooperation with the Maryland Geological Survey (MGS), with funding provided by the City of Baltimore and MDE, is examining sediment accumulation in Loch Raven Reservoir. The Baltimore City Department of Public Works periodically determines the amount of water that can be stored in its reservoirs. To make this determination, field crews measure the water depth along predetermined transects or ranges. These transects provide consistent locations where water depth, or bathymetric, measurements can be made. Range surveys are repeated to provide a record of the change in storage capacity due to sediment accumulation over time. Previous bathymetric surveys of Loch Raven Reservoir were performed in 1943, 1961, 1972, and 1985. Errors in data-collection and analysis methods have been assessed and documented (Baltimore City Department of Public Works, 1989). Few comparisons can be made among survey results because of changing data-collection techniques and analysis methods.

  6. Spatial variation of sediment mineralization supports differential CO2 emissions from a tropical hydroelectric reservoir.

    Science.gov (United States)

    Cardoso, Simone J; Vidal, Luciana O; Mendonça, Raquel F; Tranvik, Lars J; Sobek, Sebastian; Fábio, Roland

    2013-01-01

    Substantial amounts of organic matter (OM) from terrestrial ecosystems are buried as sediments in inland waters. It is still unclear to what extent this OM constitutes a sink of carbon, and how much of it is returned to the atmosphere upon mineralization to carbon dioxide (CO2). The construction of reservoirs affects the carbon cycle by increasing OM sedimentation at the regional scale. In this study we determine the OM mineralization in the sediment of three zones (river, transition, and dam) of a tropical hydroelectric reservoir in Brazil as well as identify the composition of the carbon pool available for mineralization. We measured sediment organic carbon mineralization rates and related them to the composition of the OM, bacterial abundance and pCO2 of the surface water of the reservoir. Terrestrial OM was an important substrate for the mineralization. In the river and transition zones most of the OM was allochthonous (56 and 48%, respectively) while the dam zone had the lowest allochthonous contribution (7%). The highest mineralization rates were found in the transition zone (154.80 ± 33.50 mg C m(-) (2) d(-) (1)) and the lowest in the dam (51.60 ± 26.80 mg C m(-) (2) d(-) (1)). Moreover, mineralization rates were significantly related to bacterial abundance (r (2) = 0.50, p hydroelectric reservoirs.

  7. Radiocarbon constraints on the coupled growth of sediment and organic carbon reservoirs in fluvial systems

    Science.gov (United States)

    Torres, M. A.; Kemeny, P. C.; Fischer, W. W.; Lamb, M. P.

    2017-12-01

    Vast amounts of sediments are stored transiently in fluvial deposits as they move in rivers from source to sink. The timescale(s) of transient storage have the potential to set the cadence for biogeochemical reactions to occur in river sediments. However, the extent to which storage modulates the chemical composition of river sediments remains unclear. In case of the organic carbon (OC) cycle, transient sediment storage may leave an imprint in the radiocarbon (14C) content of riverine particulate OC (POC), offering a potential tool to trace the coupling of sediment storage and biogeochemical cycling in river systems. We investigated the modern and ancient budgets of sediments and POC in the Efi Haukadalsá River catchment in West Iceland to provide new empirical constraints on the role of sediment storage in the terrestrial OC cycle. This field site is attractive because the basaltic bedrock is free of rock-derived (i.e. "petrogenic") POC such that bulk 14C measurements can be interpreted more directly as constraints on catchment OC storage timescales. Additionally, Lake Haukadalsvatn at the outlet of the river catchment has captured sediment for nearly 13 ka, which offers a complementary record of the evolution of climate-sediment-OC linkages since deglaciation. New 14C measurements show that bulk POC in fine grained fluvial deposits within the Haukadalsá catchment is remarkably old (model ages between 1 and 10 ka). This evidence for "aged" POC in floodplain storage is consistent with previous measurements from Lake Haukadalsvatn, which show that POC is aged in the river system by thousands of years prior to deposition in the lake. Additionally, our estimate of the mean transit time of sediments through the river system matches the millennial-scale reservoir age of riverine POC derived from 14C, which implies a tight coupling between sediment storage and the OC cycle. We interpret the long-term increase in the 14C reservoir age of riverine POC over the last 10 ka

  8. Geomorphology and sediment transport on a submerged back-reef sand apron: One Tree Reef, Great Barrier Reef

    Science.gov (United States)

    Harris, Daniel L.; Vila-Concejo, Ana; Webster, Jody M.

    2014-10-01

    Back-reef sand aprons are conspicuous and dynamic sedimentary features in coral reef systems. The development of these features influences the evolution and defines the maturity of coral reefs. However, the hydrodynamic processes that drive changes on sand aprons are poorly understood with only a few studies directly assessing sediment entrainment and transport. Current and wave conditions on a back-reef sand apron were measured during this study and a digital elevation model was developed through topographic and bathymetric surveying of the sand apron, reef flats and lagoon. The current and wave processes that may entrain and transport sediment were assessed using second order small amplitude (Stokes) wave theory and Shields equations. The morphodynamic interactions between current flow and geomorphology were also examined. The results showed that sediment transport occurs under modal hydrodynamic conditions with waves the main force entraining sediment rather than average currents. A morphodynamic relationship between current flow and geomorphology was also observed with current flow primarily towards the lagoon in shallow areas of the sand apron and deeper channel-like areas directing current off the sand apron towards the lagoon or the reef crest. These results show that the short-term mutual interaction of hydrodynamics and geomorphology in coral reefs can result in morphodynamic equilibrium.

  9. A Laboratory Experiment on the Evolution of a Sand Gravel Reach Under a Lack of Sediment Supply

    Science.gov (United States)

    Orru, C.; Chavarrias, V.; Ferrara, V.; Blom, A.

    2014-12-01

    A flume experiment was conducted to examine the evolution of a sand-gravel reach under a lack of sediment supply. The experimental data are used to validate a numerical sand-gravel model. A bed composed of a bi-modal sediment mixture is installed with a uniform slope and an imposed gradual fining pattern. Initially, the sand fraction gradually increases in streamwise direction until the bed is fully composed of sand. The water discharge and downstream water level were constant, and the sediment feed rate was equal to zero. The experiment was dominated by bed load, partial transport, and a subcritical flow regime was imposed. The flow rate was such that only sand was mobile (partial transport), which led to a coarsening over the upstream reach and a gradual reduction of the sediment transport rate during the experiment. New equipment was used to measure the evolution of the grain size distribution of the bed surface during the experiment over the entire flume using image analysis. In the upstream reach we observed a gradual coarsening over time and the formation of an armour layer, which resulted in a more abrupt transition in grain size of the bed surface. Bed degradation increased in streamwise direction. This is due to the initial streamwise increase in the availability of sand in the bed. The different volume fraction content of sand in the bed allowed for the gravel to sink more in the downstream part of the upstream reach. The sand reach suffered from a larger degradation. Finally, we see one reach dominated by sand, small bedforms, and a small bed slope, and a gravel reach dominated by a larger bed slope.

  10. Colorado River sediment transport: 2. Systematic bed‐elevation and grain‐size effects of sand supply limitation

    Science.gov (United States)

    Topping, David J.; Rubin, David M.; Nelson, Jonathan M.; Kinzel, Paul J.; Corson, Ingrid C.

    2000-01-01

    The Colorado River in Marble and Grand Canyons displays evidence of annual supply limitation with respect to sand both prior to [Topping et al, this issue] and after the closure of Glen Canyon Dam in 1963. Systematic changes in bed elevation and systematic coupled changes in suspended‐sand concentration and grain size result from this supply limitation. During floods, sand supply limitation either causes or modifies a lag between the time of maximum discharge and the time of either maximum or minimum (depending on reach geometry) bed elevation. If, at a cross section where the bed aggrades with increasing flow, the maximum bed elevation is observed to lead the peak or the receding limb of a flood, then this observed response of the bed is due to sand supply limitation. Sand supply limitation also leads to the systematic evolution of sand grain size (both on the bed and in suspension) in the Colorado River. Sand input during a tributary flood travels down the Colorado River as an elongating sediment wave, with the finest sizes (because of their lower settling velocities) traveling the fastest. As the fine front of a sediment wave arrives at a given location, the bed fines and suspended‐sand concentrations increase in response to the enhanced upstream supply of finer sand. Then, as the front of the sediment wave passes that location, the bed is winnowed and suspended‐sand concentrations decrease in response to the depletion of the upstream supply of finer sand. The grain‐size effects of depletion of the upstream sand supply are most obvious during periods of higher dam releases (e.g., the 1996 flood experiment and the 1997 test flow). Because of substantial changes in the grain‐size distribution of the bed, stable relationships between the discharge of water and sand‐transport rates (i.e., stable sand rating curves) are precluded. Sand budgets in a supply‐limited river like the Colorado River can only be constructed through inclusion of the physical

  11. Radiometric dating of sediment core from waterwork reservoir Rozgrund and analysis of mercury concentration depth profile

    International Nuclear Information System (INIS)

    Vanek, M.

    2005-01-01

    Radioisotope dating of lake sediments combined with analysis of chemical properties of the sediment layers allow us to study the history of the human impact on nature. Undisturbed sediment layers in the core samples serve as chronicle database with information about lake ecosystem and surrounding environment in the time of deposition. A sediment core sample from the bottom of the water-work reservoir Rozgrund was collected and separated into 2 cm thick layers. Samples were analysed by HPGe spectrometry for anthropogenous Cs-137 activity. From identified peaks corresponding to nuclear tests and Chernobyl accident the sedimentation rate was calculated and the chronology of layers established. Sub-samples from each layer were prepared separately for the analysis of the Hg concentration by atomic absorption spectrometry. The results show very small variations in Hg concentrations and there is no significant trend present in the profile. (author)

  12. Trapping Efficiency of Fine Sediments in Reservoir Lake in Fukushima Rivers as Revealed by Radiocaesium attached in Suspended Sediment

    Science.gov (United States)

    Taniguchi, K.; Onda, Y.; Kuramoto, T.; Smith, H.; Blake, W.; Onuma, S.; Sato, T.; Arai, H.; Blake, W.

    2017-12-01

    Radiocaesium released from Fukushima Daiichi Nuclear Power Plant were widely distributed in the surrounded area. The radiocaesium deposited inland area were adsorbed to fine particles of the surface soils such as silt and clay particles. The contaminated particles were eroded by rainfall events, and then transported through river systems. The purpose of this research is to investigate the impact of existence of large reservoirs on the riverine transport of fine sediments by using the 137Cs as a kind of tracer. At 30 monitoring sites located in 9 river systems in the area affected by the accident, suspended sediments (SS) ware collected by time-integrated SS samplers. The particulate radiocaesium activity concentration was measured by germanium detector. The water discharge and SS flux each site were calculated by the water level and turbidity data every 10 minutes obtained by monitoring. The 137Cs flux was calculated by multiplying the activity concentration and the SS flux. The Cs-137 flux normalized by the water discharge and initial deposition of 137Cs in the watershed (L/QD) showed a correlation with the coverages of land use types in the watershed in the case of monitoring sites where there was no large reservoir in the watershed. However, at the sites that have large reservoir in the watershed, the value of L/QD were 6.5 -21 % of the values estimated by the coverage of land use types. This result implies that approximately more than 80 % of the fine SS is trapped by the reservoirs.

  13. Correlation of aeolian sediment transport measured by sand traps and fluorescent tracers

    Science.gov (United States)

    Cabrera, Laura L.; Alonso, Ignacio

    2010-03-01

    Two different methods, fluorescent tracers and vertical sand traps, were simultaneously used to carry out an aeolian sediment transport study designed to test the goodness of fluorescent tracers in aeolian environments. Field experiments were performed in a nebkha field close to Famara beach at Lanzarote Island (Canary Islands, Spain) in a sector where the dunes were between 0.5 and 0.8 m height and 1-2 m wide and the vegetal cover was approximately 22%. In this dune field the sediment supply comes from Famara beach and is blown by trade winds toward the south, where the vegetation acts as natural sediment traps. Wind data were obtained by means of four Aanderaa wind speed sensors and one Aanderaa vane, all them distributed in a vertical array from 0.1 to 4 m height for 27 h. The average velocity at 1 m height during the experiment was 5.26 m s - 1 with the wind direction from the north. The tracer was under wind influence for 90 min at midday. During this period two series of sand traps (T1 and T2) N, S, E and W oriented were used. Resultant transport rates were 0.0131 and 0.0184 kg m - 1 min - 1 respectively. Tracer collection was performed with a sticky tape to sample only surface sediments. Tagged grains were visually counted under UV light. The transport rate was computed from the centroid displacement, that moved 0.875 m southwards, and the depth of the active layer considered was the size of one single grain. Taking into account these data the transport rate was 0.0072 kg m - 1 min - 1 . The discrepancy in results between both methods is related to several factors, such as the thickness of the active layer and the grain size difference between the tagged and the native material.

  14. Phosphorus fractions and sorption dynamics in the sediments of two Ca-SO4 water reservoirs in the central Argentine Andes

    Institute of Scientific and Technical Information of China (English)

    José Gabriel León; Fernando Luis Pedrozo; Pedro Félix Temporetti

    2017-01-01

    Phosphorus (P) fractionation and sorption behavior were studied in the sediments of two calcium-sulfate (Ca-SO4:Ca2+170 mg L-1;SO42-400 mg L-1) water reservoirs in the southern central Argentine Andes-El Carrizal Reservoir (ECR),which stratifies in summer and El Nihuil Reservoir (ENR),which is vertically mixed throughout the year. Sediment size classes reflected the lithology of both basins and the reservoirs relative location:ECR (downstream from a valley adjacent to a mountain environment) had higher clay proportions while the sand fraction was more important in ENR (just next to a mountain environment). In both reservoirs, the chemical composition revealed low alteration and calcium enrichment. Total P content was relatively high (1.1–1.6 mg P kg-1 dry weight) as expected from the contribution of marine formations. P fractionation was dominated by Ca-P (ECR, 69%and ENR, 63%) followed by organic-P (23%) in summer-anoxic ECR and by iron/aluminum (Fe/Al)-P (27%) in oxic ENR. Batch experiments showed that sorption behavior in ECR had a typical Langmuir isotherm plot while in ENR that model fitted only at low dissolved P values (<5 mg P L-1) and co-precipitation evidence was observed at higher P con-centrations. It is proposed that lower Fe/Al-P content in anoxic (ECR) vs. oxic (ENR) sediments results from the P released from iron-bound phosphorus due to sulfate reduction-ferrous sulfide formation in an anoxic environment. This condition should enable ECR sediments to adsorb P into fresh oxidized iron, and ENR sediments to co-precipitate P with calcium due to Fe/Al-P saturation, as observed in batch experiments. This paper constitutes the first description of phosphorus content and dynamics in reser-voir sediments in arid central western Argentina, where water sulfate concentrations are naturally high due to basin lithology.

  15. Aging Reservoirs in a Changing Climate: Examining Storage Loss of Large Reservoirs and Variability of Sedimentation Rate in a Dominant Cropland Region

    Science.gov (United States)

    Rahmani, V.; Kastens, J.; deNoyelles, F.; Huggins, D.; Martinko, E.

    2015-12-01

    Dam construction has multiple environmental and hydrological consequences including impacts on upstream and downstream ecosystems, water chemistry, and streamflow. Behind the dam the reservoir can trap sediment from the stream and fill over time. With increasing population and drinking and irrigation water demands, particularly in the areas that have highly variable weather and extended drought periods such as the United States Great Plains, reservoir sedimentation escalates water management concerns. Under nearly all projected climate change scenarios we expect that reservoir water storage and management will come under intense scrutiny because of the extensive use of interstate river compacts in the Great Plains. In the state of Kansas, located in the Great Plains, bathymetric surveys have been completed during the last decade for many major lakes by the Kansas Biological Survey, Kansas Water Office, and the U.S. Army Corps of Engineers. In this paper, we studied the spatial and temporal changes of reservoir characteristics including sedimentation yield, depletion rate, and storage capacity loss for 24 federally-operated reservoirs in Kansas. These reservoirs have an average age of about 50 years and collectively have lost approximately 15% of their original capacity, with the highest annual observed single-reservoir depletion rate of 0.84% and sedimentation yield of 1,685 m3 km-2 yr-1.

  16. Deposition behavior, risk assessment and source identification of heavy metals in reservoir sediments of Northeast China.

    Science.gov (United States)

    Zhu, Lin; Liu, Jianwei; Xu, Shiguo; Xie, Zaigang

    2017-08-01

    Sediment cores from five reservoirs, located in the Liaoning and Jilin Provinces in Northeast China, were collected to investigate the accumulation and potential toxicity of heavy metals (Fe, Mn, Cu, Cd, Pb, Zn, and Cr) during a sampling campaign in February, 2015. The results showed that all the detected metals accumulated significantly, especially Cd, compared to their respective background values. Among these reservoirs, Biliuhe Reservoir had markedly increasing trends for organic matter and all the metals, among which Mn was elevated by 280% to 3411mg/kg in a core of only 18cm in depth. Xinlicheng Reservoir was characterized by heavy siltation and varying metal distribution due to its regular geometric features and pulsed flood events. The Enrichment factor (EF) and geo-accumulation index (I geo ) indicated Cd was strongly enriched by anthropogenic inputs, with the values of EF and I geo greater than 8 and 3, respectively. The toxicity assessment calculated using consensus-based sediment quality guidelines (SQGs) implied the whole cores of Tanghe and Dahuofang and the upper cores of Biliuhe, Xinlicheng and Fengman exhibited toxicity to sediment-dwelling organisms. Cr contributed more to Q m-PEC than the other heavy metals, because only Cr exceeded the probable effect concentration (PEC) despite its low enrichment. According to the results of correlation analysis (CA) and principal components analysis (PCA), mining industries and agricultural activities within the basin were the main anthropogenic pollution sources for these heavy metals. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Source, composition, and environmental implication of neutral carbohydrates in sediment cores of subtropical reservoirs, South China

    Science.gov (United States)

    Duan, Dandan; Zhang, Dainan; Yang, Yu; Wang, Jingfu; Chen, Jing'an; Ran, Yong

    2017-09-01

    Neutral monosaccharides, algal organic matter (AOM), and carbon stable isotope ratios in three sediment cores of various trophic reservoirs in South China were determined by high-performance anion-exchange chromatography, Rock-Eval pyrolysis, and Finnigan Delta Plus XL mass spectrometry, respectively. The carbon isotopic compositions were corrected for the Suess effect. The concentrations of total neutral carbohydrates (TCHO) range from 0.51 to 6.4 mg g-1 at mesotrophic reservoirs, and from 0.83 to 2.56 mg g-1 at an oligotrophic reservoir. Monosaccharide compositions and diagnostic parameters indicate a predominant contribution of phytoplankton in each of the three cores, which is consistent with the results inferred from the corrected carbon isotopic data and C/N ratios. The sedimentary neutral carbohydrates are likely to be structural polysaccharides and/or preserved in sediment minerals, which are resistant to degradation in the sediments. Moreover, the monosaccharide contents are highly related to the carbon isotopic data, algal productivity estimated from the hydrogen index, and increasing mean air temperature during the past 60 years. The nutrient input, however, is not a key factor affecting the primary productivity in the three reservoirs. The above evidence demonstrates that some of the resistant monosaccharides have been significantly elevated by climate change, even in low-latitude regions.

  18. Source, composition, and environmental implication of neutral carbohydrates in sediment cores of subtropical reservoirs, South China

    Directory of Open Access Journals (Sweden)

    D. Duan

    2017-09-01

    Full Text Available Neutral monosaccharides, algal organic matter (AOM, and carbon stable isotope ratios in three sediment cores of various trophic reservoirs in South China were determined by high-performance anion-exchange chromatography, Rock-Eval pyrolysis, and Finnigan Delta Plus XL mass spectrometry, respectively. The carbon isotopic compositions were corrected for the Suess effect. The concentrations of total neutral carbohydrates (TCHO range from 0.51 to 6.4 mg g−1 at mesotrophic reservoirs, and from 0.83 to 2.56 mg g−1 at an oligotrophic reservoir. Monosaccharide compositions and diagnostic parameters indicate a predominant contribution of phytoplankton in each of the three cores, which is consistent with the results inferred from the corrected carbon isotopic data and C∕N ratios. The sedimentary neutral carbohydrates are likely to be structural polysaccharides and/or preserved in sediment minerals, which are resistant to degradation in the sediments. Moreover, the monosaccharide contents are highly related to the carbon isotopic data, algal productivity estimated from the hydrogen index, and increasing mean air temperature during the past 60 years. The nutrient input, however, is not a key factor affecting the primary productivity in the three reservoirs. The above evidence demonstrates that some of the resistant monosaccharides have been significantly elevated by climate change, even in low-latitude regions.

  19. Purification and measurement of acid leachable europium in sands as an aid in the study of sediment transport

    International Nuclear Information System (INIS)

    Ditchburn, R.G.; McCabe, W.J.

    1982-05-01

    The use of europium labelled sand as an aid in the study of sediment transport has been suggested. A method for the purification of acid leachable europium is described. The final measurement is made by flame emission spectrometry using a nitrous oxide-acetylene flame. The usefulness of the method is limited by the natural levels of europium which, in the sand studied, was around 0.3 ppm

  20. RAPID Assessment of Extreme Reservoir Sedimentation Resulting from the September 2013 Flood, North St. Vrain Creek, CO

    Science.gov (United States)

    Rathburn, S. L.; McElroy, B. J.; Wohl, E.; Sutfin, N. A.; Huson, K.

    2014-12-01

    During mid-September 2013, approximately 360 mm of precipitation fell in the headwaters of the North St. Vrain drainage basin, Front Range, CO. Debris flows on steep hillslopes and extensive flooding along North St. Vrain Creek resulted in extreme sedimentation within Ralph Price Reservoir, municipal water supply for the City of Longmont. The event allows comparison of historical sedimentation with that of an unusually large flood because 1) no reservoir flushing has been conducted since dam construction, 2) reservoir stratigraphy chronicles uninterrupted delta deposition, and 3) this is the only on-channel reservoir with unimpeded, natural sediment flux from the Continental Divide to the mountain front in a basin with no significant historic flow modifications and land use impacts. Assessing the flood-related sedimentation prior to any dredging activities included coring the reservoir delta, a bathymetric survey of the delta, resistivity and ground penetrating radar surveys of the subaerial inlet deposit, and surveying tributary deposits. Over the 44-year life of the reservoir, two-thirds of the delta sedimentation is attributed to extreme discharges from the September 2013 storm. Total storm-derived reservoir sedimentation is approximately 275,000 m3, with 81% of that within the gravel-dominated inlet and 17% in the delta. Volumes of deposition within reservoir tributary inlets is negatively correlated with contributing area, possibly due to a lack of storage in these small basins (1-5 km2). Flood-related reservoir sedimentation will be compared to other research quantifying volumes from slope failures evident on post-storm lidar. Analysis of delta core samples will quantify organic carbon flux associated with the extreme discharge and develop a chronology of flood and fire disturbances for North St. Vrain basin. Applications of similar techniques are planned for two older Front Range reservoirs affected by the September flooding to fill knowledge gaps about

  1. Suspended-sediment loads, reservoir sediment trap efficiency, and upstream and downstream channel stability for Kanopolis and Tuttle Creek Lakes, Kansas, 2008-10

    Science.gov (United States)

    Juracek, Kyle E.

    2011-01-01

    Continuous streamflow and turbidity data collected from October 1, 2008, to September 30, 2010, at streamgage sites upstream and downstream from Kanopolis and Tuttle Creek Lakes, Kansas, were used to compute the total suspended-sediment load delivered to and released from each reservoir as well as the sediment trap efficiency for each reservoir. Ongoing sedimentation is decreasing the ability of the reservoirs to serve several purposes including flood control, water supply, and recreation. River channel stability upstream and downstream from the reservoirs was assessed using historical streamgage information. For Kanopolis Lake, the total 2-year inflow suspended-sediment load was computed to be 600 million pounds. Most of the suspended-sediment load was delivered during short-term, high-discharge periods. The total 2-year outflow suspended-sediment load was computed to be 31 million pounds. Sediment trap efficiency for the reservoir was estimated to be 95 percent. The mean annual suspended-sediment yield from the upstream basin was estimated to be 129,000 pounds per square mile per year. No pronounced changes in channel width were evident at five streamgage sites located upstream from the reservoir. At the Ellsworth streamgage site, located upstream from the reservoir, long-term channel-bed aggradation was followed by a period of stability. Current (2010) conditions at five streamgages located upstream from the reservoir were typified by channel-bed stability. At the Langley streamgage site, located immediately downstream from the reservoir, the channel bed degraded 6.15 feet from 1948 to 2010. For Tuttle Creek Lake, the total 2-year inflow suspended-sediment load was computed to be 13.3 billion pounds. Most of the suspended-sediment load was delivered during short-term, high-discharge periods. The total 2-year outflow suspended-sediment load was computed to be 327 million pounds. Sediment trap efficiency for the reservoir was estimated to be 98 percent. The mean

  2. Sediment monitoring and benthic faunal sampling adjacent to the Sand Island ocean outfall, Oahu, Hawaii, 1986-2010 (NODC Accession 9900088)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic fauna and sediment in the vicinity of the Sand Island ocean outfall were sampled from 1986-2010. To assess the environmental quality, sediment grain size and...

  3. 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...

  4. Micro and macro constituents of sediment cores from Itupararanga reservoir Sorocaba, SP, by INAA

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Sharlleny A.; Ferreira, Francisco J., E-mail: shasilva@sp.gov.br [Companhia Ambiental do Estado de Sao Paulo (ELAI/CETESB), SP (Brazil). Setor de Quimica Inorganica; Bevilacqua, Jose Eduardo [Companhia Ambiental do Estado de Sao Paulo (CETESB), Osasco, SP (Brazil). Diretoria de Avaliacao de Impacto Ambiental; Favaro, Deborah I.T., E-mail: defavaro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (LAN-CRPq/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica

    2013-07-01

    The Itupararanga reservoir was constructed by LIGHT for generating electrical energy, starting its operations in 1912. It is formed by the Sorocaba river dam. The reservoir finds itself in an area of strong environmental pressures. The waters of the Itupararanga reservoir are currently also used to supply approximately 63% of the basin of Sorocaba, in addition to power generation and recreation areas of nearby cities. Since 2003 it keeps receiving alerts from CETESB (Environmental Company of Sao Paulo State) that continues today. In this study four geo-referenced sampling points were used and bottom sediment samples were collected, were collected using a 60 cm core sampler, sliced at every 10 cm. The sediment samples were dried at 40 deg C, ground in an agate mortar, sieved (200 mesh) and again homogenized. Instrumental neutron activation analysis was applied to the sediment samples in order to determine some major elements (Fe, K and Na) and trace (As, Ba, Br, Co, Cr, Cs, Hf, Rb, Sb, Sc, Ta, Tb, Th, U and Zn) and rare earth (Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) metals. The validation of the analytical methodology was performed by the analysis of certified reference materials. The results obtained were compared to NASC (North American Shale Composite) and UCC (Upper Continental Crust) reference values. The enrichment factors (EF) was assessed for sediment contamination index. Statistical tools of Factorial and Cluster analyses were applied to the data. (author)

  5. Reservoir and contaminated sediments impacts in high-Andean environments: Morphodynamic interactions with biogeochemical processes

    Science.gov (United States)

    Escauriaza, C. R.; Contreras, M. T.; Müllendorff, D. A.; Pasten, P.; Pizarro, G. E.

    2014-12-01

    Rapid changes due to anthropic interventions in high-altitude environments, such as the Altiplano region in South America, require new approaches to understand the connections between physical and biogeochemical processes. Alterations of the water quality linked to the river morphology can affect the ecosystems and human development in the long-term. The future construction of a reservoir in the Lluta river, located in northern Chile, will change the spatial distribution of arsenic-rich sediments, which can have significant effects on the lower parts of the watershed. In this investigation we develop a coupled numerical model to predict and evaluate the interactions between morphodynamic changes in the Lluta reservoir, and conditions that can potentially desorb arsenic from the sediments. Assuming that contaminants are mobilized under anaerobic conditions, we calculate the oxygen concentration within the sediments to study the interactions of the delta progradation with the potential arsenic release. This work provides a framework for future studies aimed to analyze the complex connections between morphodynamics and water quality, when contaminant-rich sediments accumulate in a reservoir. The tool can also help to design effective risk management and remediation strategies in these extreme environments. Research has been supported by Fondecyt grant 1130940 and CONICYT/FONDAP Grant 15110017

  6. Sediment-water interactions affecting dissolved-mercury distributions in Camp Far West Reservoir, California

    Science.gov (United States)

    Kuwabara, James S.; Alpers, Charles N.; Marvin-DiPasquale, Mark; Topping, Brent R.; Carter, James L.; Stewart, A. Robin; Fend, Steven V.; Parcheso, Francis; Moon, Gerald E.; Krabbenhoft, David P.

    2003-01-01

    Field and laboratory studies were conducted in April and November 2002 to provide the first direct measurements of the benthic flux of dissolved (0.2-micrometer filtered) mercury species (total and methylated forms) between the bottom sediment and water column at three sampling locations within Camp Far West Reservoir, California: one near the Bear River inlet to the reservoir, a second at a mid-reservoir site of comparable depth to the inlet site, and the third at the deepest position in the reservoir near the dam (herein referred to as the inlet, midreservoir and near-dam sites, respectively; Background, Fig. 1). Because of interest in the effects of historic hydraulic mining and ore processing in the Sierra Nevada foothills just upstream of the reservoir, dissolved-mercury species and predominant ligands that often control the mercury speciation (represented by dissolved organic carbon, and sulfides) were the solutes of primary interest. Benthic flux, sometimes referred to as internal recycling, represents the transport of dissolved chemical species between the water column and the underlying sediment. Because of the affinity of mercury to adsorb onto particle surfaces and to form insoluble precipitates (particularly with sulfides), the mass transport of mercury in mining-affected watersheds is typically particle dominated. As these enriched particles accumulate at depositional sites such as reservoirs, benthic processes facilitate the repartitioning, transformation, and transport of mercury in dissolved, biologically reactive forms (dissolved methylmercury being the most bioavailable for trophic transfer). These are the forms of mercury examined in this study. In contrast to typical scientific manuscripts, this report is formatted in a pyramid-like structure to serve the needs of diverse groups who may be interested in reviewing or acquiring information at various levels of technical detail (Appendix 1). The report enables quick transitions between the initial

  7. Rational Rock Physics for Improved Velocity Prediction and Reservoir Properties Estimation for Granite Wash (Tight Sands in Anadarko Basin, Texas

    Directory of Open Access Journals (Sweden)

    Muhammad Z. A. Durrani

    2014-01-01

    Full Text Available Due to the complex nature, deriving elastic properties from seismic data for the prolific Granite Wash reservoir (Pennsylvanian age in the western Anadarko Basin Wheeler County (Texas is quite a challenge. In this paper, we used rock physics tool to describe the diagenesis and accurate estimation of seismic velocities of P and S waves in Granite Wash reservoir. Hertz-Mindlin and Cementation (Dvorkin’s theories are applied to analyze the nature of the reservoir rocks (uncemented and cemented. In the implementation of rock physics diagnostics, three classical rock physics (empirical relations, Kuster-Toksöz, and Berryman models are comparatively analyzed for velocity prediction taking into account the pore shape geometry. An empirical (VP-VS relationship is also generated calibrated with core data for shear wave velocity prediction. Finally, we discussed the advantages of each rock physics model in detail. In addition, cross-plots of unconventional attributes help us in the clear separation of anomalous zone and lithologic properties of sand and shale facies over conventional attributes.

  8. Provenance of the heavy metals in sand sediments of the Oman Sea (Sistan and Baluchestan district

    Directory of Open Access Journals (Sweden)

    Maryam Soleimani

    2015-04-01

    Full Text Available Introduction Mineral composition of source rock is one of the most important factors for concentration and distribution of heavy metals in sediments. Therefore, study on distribution of these elements and the related minerals in sediments provides information about natural origin of elements. Moreover, the interpretation of origin and distribution of sandy sediments is considerably enhanced by mineralogical and geochemical studies of these sediments. The main objective of this research is to evaluate distribution of Zn, Cu, Sr, Cd, Fe and Mn in sand sediments of the Oman Sea, their relationship with mineral composition of the sediments and also determining their provenance. Materials and Methods Sampling of surface sediments of the Oman Sea was performed in 16 sampling stations. Heavy minerals and rock fragments of the sediments in fine and coarse sand sizes respectively were qualitatively and quantitatively studied by polarizing microscope (Folk, 1974; Pettijohn et al., 1981; Tucker, 1988. Concentration of the heavy metals were also analyzed by AAS method (Mico et al., 2008. Result Mineralogical composition of the studied sediments contain quartz, feldspars and heavy minerals in their order of abundances. The rock fragments consist of sedimentary, igneous and metamorphic in their order of frequencies as well. The concentrations of the studied heavy metals (in ppm in the sediments are Cd (1.42, Cu (9.99, Zn (36.72, Sr (181.18, Mn (377.33 and Fe (20247.55 in their order of abundances. Distribution of the Zn concentration generally shows decreasing trend from west of the study area to the Guatr Bay. The concentrations of Zn and Cu show close relationship with the frequencies of biotite and muscovite. The Cu concentration also shows positive correlation with the Zn and Fe concentrations. Distribution of the Sr and Cd concentrations is similar to variation of the calcium carbonate content. The Cd and Sr concentrations also show positive correlation

  9. Major and trace elements assessment in sediment samples from Rio Grande Reservoir, by neutron activation analysis

    International Nuclear Information System (INIS)

    Franklin, Robson L.; Ferreira, Francisco J.; Favaro, Deborah I.T.; Bevilacqua, Jose Eduardo

    2009-01-01

    The Rio Grande Reservoir, Southeast of the Sao Paulo Metropolitan Area (SPMA) supplies water for four counties (Sao Bernardo do Campo, Sao Caetano do Sul, Santo Andre and Diadema). It has been seriously affected by urban expansion, due to chaotic urban occupation and improper use of the surrounding areas. In this study bottom sediment samples were collected, by using a Van Veen sampler, during the dry and rainy seasons. Four sampling points were defined by using GPS and are located at the mouth of the Rio Grande and Ribeirao Pires Rivers, in the middle of the reservoir and near the catchment point of the water supply. The sediment samples were submitted to instrumental neutron activation analysis (INAA) and the following elements were determined: As, Ba, Br, Co, Cr, Cs, Rb, Sb, Sc, Se, Ta, Th, U e Zn and the rare earth elements Ce, Eu, La, Lu, Nd, Sm, Tb, Yb. Short irradiation was also performed for total Hg determination by NAA using 197 Hg radioisotope. This was possible due to the high Hg concentration levels in these sediments. The methodology validation was carried out by certified reference material analyses. The results obtained for multielemental concentrations in the sediment samples were compared to NASC (North American Shale Composite) values. The concentration values obtained for As and metals Cr, Hg and Zn in the sediment samples were compared to the Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values) and adopted by CETESB. (author)

  10. Bathymetry and Sediment-Storage Capacity Change in Three Reservoirs on the Lower Susquehanna River, 1996-2008

    Science.gov (United States)

    Langland, Michael J.

    2009-01-01

    The Susquehanna River transports a substantial amount of the sediment and nutrient load to the Chesapeake Bay. Upstream of the bay, three large dams and their associated reservoirs trap a large amount of the transported sediment and associated nutrients. During the fall of 2008, the U.S. Geological Survey in cooperation with the Pennsylvania Department of Environmental Protection completed bathymetric surveys of three reservoirs on the lower Susquehanna River to provide an estimate of the remaining sediment-storage capacity. Previous studies indicated the upper two reservoirs were in equilibrium with long-term sediment storage; only the most downstream reservoir retained capacity to trap sediments. A differential global positioning system (DGPS) instrument was used to provide the corresponding coordinate position. Bathymetry data were collected using a single beam 210 kHz (kilohertz) echo sounder at pre-defined transects that matched previous surveys. Final horizontal (X and Y) and vertical (Z) coordinates of the geographic positions and depth to bottom were used to create bathymetric maps of the reservoirs. Results indicated that from 1996 to 2008 about 14,700,000 tons of sediment were deposited in the three reservoirs with the majority (12,000,000 tons) being deposited in Conowingo Reservoir. Approximately 20,000 acre-feet or 30,000,000 tons of remaining storage capacity is available in Conowingo Reservoir. At current transport (3,000,000 tons per year) and deposition (2,000,000 tons per year) rates and with no occurrence of major scour events due to floods, the remaining capacity may be filled in 15 to 20 years. Once the remaining sediment-storage capacity in the reservoirs is filled, sediment and associated phosphorus loads entering the Chesapeake Bay are expected to increase.

  11. Development of a bioassay using walleye (Sander vitreus) to assess the toxicity of oil sands sediments

    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

    This study examined the effects of sediments from the Athabasca oil sands area on fish development and survival. Walleye (Sander vitreus) which inhabit the Athabasca River are exposed to natural sources of bitumen eroding from the McMurray formation. This study described the design and implementation of a daily-renewal bioassay to evaluate the potential effects of toxicants on walleye development. Eggs were collected and fertilized with milt from spawning wild walleye 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. The walleye embryos were fed brine shrimp daily after hatching and the developing fish were examined for morphological deformities, survival, hatching success, and changes in weight and length between treatments. Organics concentrations in fish tissues and water were measured when possible. Fathead minnows and northern pikes will also be exposed to the same sediments in order to compare the relative sensitivity of the three species.

  12. Metal cycling during sediment early diagenesis in a water reservoir affected by acid mine drainage

    DEFF Research Database (Denmark)

    Torres, Ester; Ayora, Carlos; Canovas, C. R.

    2013-01-01

    The discharge of acid mine drainage (AMD) into a reservoir may seriously affect the water quality. To investigate the metal transfer between the water and the sediment, three cores were collected from the Sancho Reservoir (Iberian Pyrite Belt, SW Spain) during different seasons: turnover event......; oxic, stratified period; anoxic and under shallow perennially oxic conditions. The cores were sliced in an oxygen-free atmosphere, after which pore water was extracted by centrifugation and analyzed. A sequential extraction was then applied to the sediments to extract the water-soluble, monosulfide......, low crystallinity Fe(III)-oxyhydroxide, crystalline Fe(III)-oxide, organic, pyrite and residual phases. The results showed that, despite the acidic chemistry of the water column (pH

  13. Multicomponent seismic reservoir characterization of a steam-assisted gravity drainage (SAGD) heavy oil project, Athabasca oil sands, Alberta

    Science.gov (United States)

    Schiltz, Kelsey Kristine

    Steam-assisted gravity drainage (SAGD) is an in situ heavy oil recovery method involving the injection of steam in horizontal wells. Time-lapse seismic analysis over a SAGD project in the Athabasca oil sands deposit of Alberta reveals that the SAGD steam chamber has not developed uniformly. Core data confirm the presence of low permeability shale bodies within the reservoir. These shales can act as barriers and baffles to steam and limit production by prohibiting steam from accessing the full extent of the reservoir. Seismic data can be used to identify these shale breaks prior to siting new SAGD well pairs in order to optimize field development. To identify shale breaks in the study area, three types of seismic inversion and a probabilistic neural network prediction were performed. The predictive value of each result was evaluated by comparing the position of interpreted shales with the boundaries of the steam chamber determined through time-lapse analysis. The P-impedance result from post-stack inversion did not contain enough detail to be able to predict the vertical boundaries of the steam chamber but did show some predictive value in a spatial sense. P-impedance from pre-stack inversion exhibited some meaningful correlations with the steam chamber but was misleading in many crucial areas, particularly the lower reservoir. Density estimated through the application of a probabilistic neural network (PNN) trained using both PP and PS attributes identified shales most accurately. The interpreted shales from this result exhibit a strong relationship with the boundaries of the steam chamber, leading to the conclusion that the PNN method can be used to make predictions about steam chamber growth. In this study, reservoir characterization incorporating multicomponent seismic data demonstrated a high predictive value and could be useful in evaluating future well placement.

  14. Comparison of Mercury in Water, Bottom Sediment, and Zooplankton in Two Front Range Reservoirs in Colorado, 2008-09

    Science.gov (United States)

    Mast, M. Alisa; Krabbenhoft, David P.

    2010-01-01

    The U.S. Geological Survey, in cooperation with the Colorado Department of Public Health and Environment, conducted a study to investigate environmental factors that may contribute to the bioaccumulation of mercury in two Front Range reservoirs. One of the reservoirs, Brush Hollow Reservoir, currently (2009) has a fish-consumption advisory for mercury in walleye (Stizostedion vitreum), and the other, Pueblo Reservoir, which is nearby, does not. Water, bottom sediment, and zooplankton samples were collected during 2008 and 2009, and a sediment-incubation experiment was conducted in 2009. Total mercury concentrations were low in midlake water samples and were not substantially different between the two reservoirs. The only water samples with detectable methylmercury were collected in shallow areas of Brush Hollow Reservoir during spring. Mercury concentrations in reservoir bottom sediments were similar to those reported for stream sediments from unmined basins across the United States. Despite higher concentrations of fish-tissue mercury in Brush Hollow Reservoir, concentrations of methylmercury in sediment were as much as 3 times higher in Pueblo Reservoir. Mercury concentrations in zooplankton were at the low end of concentrations reported for temperate lakes in the Northeastern United States and were similar between sites, which may reflect the seasonal timing of sampling. Factors affecting bioaccumulation of mercury were assessed, including mercury sources, water quality, and reservoir characteristics. Atmospheric deposition was determined to be the dominant source of mercury; however, due to the proximity of the reservoirs, atmospheric inputs likely are similar in both study areas. Water-quality constituents commonly associated with elevated concentrations of mercury in fish (pH, alkalinity, sulfate, nutrients, and dissolved organic carbon) did not appear to explain differences in fish-tissue mercury concentrations between the reservoirs. Low methylmercury

  15. Report on water quality, sediment and water chemistry data for water and sediment samples collected from source areas to Melton Hill and Watts Bar reservoirs

    International Nuclear Information System (INIS)

    Tomaszewski, T.M.; Bruggink, D.J.; Nunn, D.L.

    1995-01-01

    Contamination of surface water and sediments in the Clinch River and Watts Bar Reservoir (CR/WBR) system as a result of past and present activities by the US Department of Energy (DOE) on the Oak Ridge Reservation (ORR) and also activities by non-ORR facilities are being studied by the Clinch River Environmental Restoration Program (CR-ERP). Previous studies have documented the presence of heavy metals, organics, and radionuclides in the sediments of reservoirs in the vicinity. In support of the CR-ERP, during the summer of 1991, TVA collected and evaluated water and sediment samples from swimming areas and municipal water intakes on Watts Bar Reservoir, Melton Hill Reservoir and Norris Reservoir, which was considered a source of less-contaminated reference or background data. Despite the numerous studies, until the current work documented by this report, relatively few sediment or water samples had been collected by the CR-ERP in the immediate vicinity of contaminant point sources. This work focused on water and sediment samples taken from points immediately downstream from suspected effluent point sources both on and off the ORR. In August and September, 1994, TVA sampled surface water and sediment at twelve locations in melton Hill and Watts Bar Reservoirs

  16. Patterns of sediment accumulation in Watts Bar Reservoir based on 137Cesium

    International Nuclear Information System (INIS)

    Brandt, C.C.; Rose, K.A.; Cook, R.B.; Dearstone, K.C.; Brenkert, A.L.; Olsen, C.R.

    1991-01-01

    The US Department of Energy has recently undertaken an environmental restoration program designed to achieve remediation of hazardous materials released from the Oak Ridge Reservation (ORR). The distribution of 137 Cs was investigated in sediments from Watts Barr Reservoir and the Clinch River as a possible marker for other contaminants released from the ORR. We have performed additional analyses on the data gathered for this study to investigate possible relationships between 137 Cs accumulation and reservoir characteristics. We found that 137 Cs deposition correlates with sedimentation rate, and soft mud layers of cores have higher 137 Cs levels than sandy mud or eroded soils. No correlation was found with water depth, distance from shore or distance from release source, but it is important to note the data were not collected to test for these effects. We estimate Watts Barr Reservoir contains 267 Ci of 137 Cs, with 7% of this total in the top 16 cm of sediment, and potentially available for biological accumulation. 2 refs

  17. Distribution, sedimentation, and bioavailability of particulate phosphorus in the mainstream of the Three Gorges Reservoir.

    Science.gov (United States)

    Tang, Xianqiang; Wu, Min; Li, Rui

    2018-09-01

    The transportation and sedimentation of particulate phosphorus (PP) in a huge reservoir such as the Three Gorges Reservoir (TGR) are closely related to the phosphorus distribution characteristics and nutritional status of the water body. In this study, the PP distribution, sedimentation, and bioavailability in the mainstream section of the TGR were investigated through a field survey, indoor simulated settlement experiment, and historical data analysis. The results indicated that PP was the major component of the total phosphorus (TP) and that the Three Gorges Dam (TGD) trapped nearly 76.25% of suspended sediment (SS) and 75.35% of PP in the TGR, even during the flood season. A decline in flow velocity promoted the deposition of PP; additionally, PP concentrations gradually dropped from 0.35 mg/L in Chongqing to 0.02 mg/L in Zigui. The static PP sedimentation process adequately fitted a pseudo-second-order kinetic equation with a maximum correlation coefficient of 0.97. Moreover, more than half of the PP sedimentation process was achieved in less than 60 min for samples collected from the upper river reaches within simulated sedimentation process. The median particle size of SS and absolute value of the water column's zeta potential were negatively and positively related to the t 12 values of PP sedimentation, respectively. Compared with the concentration and particle size of SS obtained in the pre-TGR period, the values in the mainstream section of the TGR were lower. However, the TP and Fe/Al-P contents in SS increased several times. Due to the combined effects of flow velocity reduction and SS trapping, the water transparency and bioavailability of water column phosphorus were enhanced. Thus, the risk of water bloom outburst significantly increased when the impounded water level of 175 m in the TGR became the normal state. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Count rate balance method of measuring sediment transport of sand beds by radioactive tracers

    International Nuclear Information System (INIS)

    Sauzay, G.

    1968-01-01

    Radioactive tracers are applied to the direct measurement of the sediment transport rate of sand beds. The theoretical measurement formula is derived: the variation of the count rate balance is inverse of that of the transport thickness. Simultaneously the representativeness of the tracer is critically studied. The minimum quantity of tracer which has to be injected in order to obtain a correct statistical definition of count rate given by a low number of grains 'seen' by the detector is then studied. A field experiment was made and has let to study the technological conditions for applying this method: only the treatment of results is new, the experiment itself is carried out with conventional techniques applied with great care. (author) [fr

  19. Major and trace elements assessment in sediment from Ituparanga reservoir, by activation analysis and ICP OES

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Sharlleny A., E-mail: sharllenya@cetesbnet.sp.gov.br [Companhia de Tecnologia de Saneamento Ambiental (CETESB), Sao Paulo, SP (Brazil). Lab. de Quimica Inorganica; Bevilacqua, Jose Eduardo [Companhia de Tecnologia de Saneamento Ambiental (CETESB), Sao Paulo, SP (Brazil). Diretoria de Tecnologia, Qualidade e Avaliacao Ambiental; Favaro, Deborah I.T., E-mail: defavaro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica

    2011-07-01

    The Ituparanga reservoir was built to generate electric power by the LIGHT Company and started its operation in 1912. It is fed by the Una, Sorocamirim and Sorocabucu rivers. This reservoir supplies water to a population of 600.000. This water system is affected by irregular soil occupation and urban development which has caught CETESB's (Environmental Company of Sao Paulo State) attention. In this study four geo-referenced sampling points were used and bottom sediment samples were collected. The sediment samples were dried at 400 deg C, ground in an agate mortar, sieved (200 mesh) and again homogenized. The instrumental neutron activation analysis was applied to the sediment samples in order to determine some major elements (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Rb, Sb, Sc, Ta, Tb, Th, U and Zn) and rare earth (Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) elements. By using ICP OES metals determination for Cd, Cr, Cu, Pb and Ni was undertaken after digestion procedure according to the 3051 method from US EPA. The methodology validation for precision and accuracy was carried out by reference material analyses. For metals Cd, Cr, Cu, Pb and Ni the concentration values were compared to the oriented values from Environmental Canada (TEL and PEL). The Enrichment Factor (EF) was calculated for sediment contamination assessment. (author)

  20. Major and trace elements assessment in sediment from Ituparanga reservoir, by activation analysis and ICP OES

    International Nuclear Information System (INIS)

    Silva, Sharlleny A.; Bevilacqua, Jose Eduardo; Favaro, Deborah I.T.

    2011-01-01

    The Ituparanga reservoir was built to generate electric power by the LIGHT Company and started its operation in 1912. It is fed by the Una, Sorocamirim and Sorocabucu rivers. This reservoir supplies water to a population of 600.000. This water system is affected by irregular soil occupation and urban development which has caught CETESB's (Environmental Company of Sao Paulo State) attention. In this study four geo-referenced sampling points were used and bottom sediment samples were collected. The sediment samples were dried at 400 deg C, ground in an agate mortar, sieved (200 mesh) and again homogenized. The instrumental neutron activation analysis was applied to the sediment samples in order to determine some major elements (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Rb, Sb, Sc, Ta, Tb, Th, U and Zn) and rare earth (Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) elements. By using ICP OES metals determination for Cd, Cr, Cu, Pb and Ni was undertaken after digestion procedure according to the 3051 method from US EPA. The methodology validation for precision and accuracy was carried out by reference material analyses. For metals Cd, Cr, Cu, Pb and Ni the concentration values were compared to the oriented values from Environmental Canada (TEL and PEL). The Enrichment Factor (EF) was calculated for sediment contamination assessment. (author)

  1. Radionuclides and stable elements in the sediments of the Yesa Reservoir, Central Spanish Pyrenees

    Energy Technology Data Exchange (ETDEWEB)

    Navas, Ana; Gaspar, Leticia; Palazon, Leticia [Estacion Experimental Aula Dei (EEAD- CSIC), Zaragoza (Spain). Dept. of Soil and Water; Valero-Garces, Blas [Instituto Pirenaico de Ecologia (IPE-CSIC), Zaragoza (Spain)

    2011-09-15

    Purpose: The sediments accumulated in the Yesa Reservoir (Central Spanish Pyrenees) have greatly decreased its water storage capacity and are a major threat to the sustainability of water resources in the region. This study examines the contents of radionuclides and stable elements in the reservoir sediments and relates their variations with the sediment composition and local sedimentary dynamics, particularly flood frequency and intensity, which are responsible for changes in the main supply and distribution of radionuclides in the basin. Materials and methods: The sedimentary sequence accumulated in the Yesa Reservoir (471 Hm{sup 3}), which supplies water to ca. 1,000,000 people and for irrigation, was examined in two 4-m long sediment cores (Y1, Y2) and one profile (Y3) retrieved at its central part. In the sediments, radionuclide activities of {sup 238}U, {sup 226}Ra, {sup 232}Th, {sup 40}K, {sup 210}Pb and {sup 137}Cs were measured using a hyperpure Ge coaxial detector. The stable elements Mg, Ca, Sr, Ba, Cr, Cu, Mn, Fe, Al, Zn, Ni, Co, Pb, Li, K and Na were analysed by ICP-OES. Complementary analyses to characterize the sediments included: XRD in the profile, grain size distribution by laser equipment and the contents of organic matter, carbonates and the residual fraction by loss on ignition. Results and discussion: The variation in radionuclide activities is associated with grain size and sediment composition. The activity levels (becquerels per kilogram) ranged between 20 and 43 for{sup 238}U, 14 and 40 for {sup 226}Ra, 7 and 56 for {sup 210}Pb, 19 and 46 for Th{sup 232}, 1 and 48 for {sup 137}Cs and 185 and 610 for {sup 40}K. Enriched activity levels are associated with clayey and silty layers, and depleted levels with sandy layers. The levels of radionuclides and trace elements were significantly lower in the cores than in the profile because of its higher silicate content and the influence of inflow of spring mineral-rich waters. The correlations among

  2. Vertical and horizontal distribution of sediment nitrite-dependent methane-oxidizing organisms in a mesotrophic freshwater reservoir.

    Science.gov (United States)

    Long, Yan; Liu, Changbao; Lin, Hengliang; Li, Ningning; Guo, Qingwei; Xie, Shuguang

    2017-06-01

    In the present study, we investigated the spatial change of sediment nitrite-dependent anaerobic methane-oxidizing (n-damo) organisms in the mesotrophic freshwater Gaozhou Reservoir (6 different sampling locations and 2 sediment depths (0-5 cm, 5-10 cm)), one of the largest drinking water reservoirs in China. The abundance of sediment n-damo bacteria was quantified using quantitative polymerase chain reaction assay, while the richness, diversity, and composition of n-damo pmoA gene sequences were characterized using clone library analysis. Vertical and horizontal changes in sediment n-damo bacterial abundance occurred in Gaozhou Reservoir, with 1.37 × 10 5 to 8.24 × 10 5 n-damo 16S rRNA gene copies per gram of dry sediment. Considerable horizontal and vertical variations of n-damo pmoA gene diversity (Shannon index = 0.32-2.50) and composition also occurred in this reservoir. Various types of sediment n-damo pmoA genes existed in Gaozhou Reservoir. A small proportion of n-damo pmoA gene sequences (19.1%) were related to those recovered from "Candidatus Methylomirabilis oxyfera". Our results suggested that sediment n-damo pmoA gene diversity might be regulated by nitrite, while n-damo pmoA gene richness might be governed by multiple environmental factors, including total organic carbon, total phosphorus, nitrite, and total nitrogen.

  3. Reconstructing suspended sediment mercury contamination of a steep, gravel-bed river using reservoir theory

    Science.gov (United States)

    Skalak, Katherine; Pizzuto, James

    2014-01-01

    We use sediment ages and mercury (Hg) concentrations to estimate past and future concentrations in the South River, Virginia, where Hg was released between 1930 and 1950 from a manufacturing process related to nylon production. In a previous study, along a 40 km (25 mi) reach, samples were collected from 26 of 54 fine-grained deposits that formed in the lee of large wood obstructions in the channel and analyzed for grain size, Hg concentration, and organic content. We also obtained radiometric dates from six deposits. To create a history that reflects the full concentration distribution (which contains concentrations as high as 900 mg/kg [900 ppm]), here, we treat the deposits as a single reservoir exchanging contaminated sediments with the overlying water column, and assume that the total sediment mass in storage and the distribution of sediment ages are time invariant. We use reservoir theory to reconstruct the annual history of Hg concentration on suspended sediment using data from our previous study and new results presented here. Many different reconstructed histories fit our data. To constrain results, we use information from a well-preserved core (and our estimate of the total mass of Hg stored in 2007) to specify the years associated with the peak concentration of 900 mg/kg. Our results indicate that around 850 kg (1874 lb) of Hg was stored in the deposits between 1955 and 1961, compared to only 80 kg (176 lb) today. Simulations of future Hg remediation suggest that 100-yr timescales will be needed for the South River to remove Hg-contaminated sediments from the channel perimeter through natural processes.

  4. Short-term impact of deep sand extraction and ecosystem-based landscaping on macrozoobenthos and sediment characteristics.

    Science.gov (United States)

    de Jong, Maarten F; Baptist, Martin J; Lindeboom, Han J; Hoekstra, Piet

    2015-08-15

    We studied short-term changes in macrozoobenthos in a 20m deep borrow pit. A boxcorer was used to sample macrobenthic infauna and a bottom sledge was used to sample macrobenthic epifauna. Sediment characteristics were determined from the boxcore samples, bed shear stress and near-bed salinity were estimated with a hydrodynamic model. Two years after the cessation of sand extraction, macrozoobenthic biomass increased fivefold in the deepest areas. Species composition changed significantly and white furrow shell (Abra alba) became abundant. Several sediment characteristics also changed significantly in the deepest parts. Macrozoobenthic species composition and biomass significantly correlated with time after cessation of sand extraction, sediment and hydrographical characteristics. Ecosystem-based landscaped sand bars were found to be effective in influencing sediment characteristics and macrozoobenthic assemblage. Significant changes in epifauna occurred in deepest parts in 2012 which coincided with the highest sedimentation rate. We recommend continuing monitoring to investigate medium and long-term impacts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Phase transition behavior of sediment transport at the sand-mud interface, across scales from flumes to the large rivers

    Science.gov (United States)

    Ma, H.; Nittrouer, J. A.; Wu, B.; Zhang, Y.; Mohrig, D. C.; Lamb, M. P.; Wang, Y.; Fu, X.; Moodie, A. J.; Naito, K.; Parker, G.

    2017-12-01

    Sediment dispersal and deposition creates deltaic landscapes, establishes coastlines, and produces fertile floodplains, all of which serve as critical landforms inhabited by a large proportion of humankind. If poorly managed, sediment loads in these environments can elevate and clog channels, thereby enhancing hazards such as severe flooding. Predictive descriptions of sediment loads, however, are not well constrained, especially for fine-grained (silt and very-fine sand) dispersal systems, which often include river deltas and coastlines. Here, we show efforts to collect and analyze an extensive sediment load database for fine-grained channels, spanning from small flume experiments to large rivers, in order to evaluate the nature of sediment flux. Our analyses determined that sediment transport exhibits two distinct transport phases, separated by a discontinuous transition, whereby sediment flux differs by one to two orders of magnitude. It is determined that the transition responds to the bed material grain size, and we propose a phase diagram based on this metric alone. These findings help elucidate why previous theories of sediment transport at the sand-silt interface, which are typically continuous, are not able to give satisfactory predictions across different scales and environments. Our work serves to help evaluate anthropic influences on rivers, deltas, and coastlines, and can be applied to better constrain sediment flux of paleo-fluvial systems found on Earth and Mars. For example, in situ measurements of sediment flux for the silty-sandy bed of the lower Yellow River, China, validate the aforementioned phase transition behavior, and illustrate that the channel resides near the transition of high to low efficiency transport modes. Recent dam construction and resulting downstream coarsening of the bed via armoring, however, might lead to the unintended consequence of enhancing flood risk by driving the system to a low efficiency transport mode with high

  6. Soil erosion and sediment fluxes analysis: a watershed study of the Ni Reservoir, Spotsylvania County, VA, USA.

    Science.gov (United States)

    Pope, Ian C; Odhiambo, Ben K

    2014-03-01

    Anthropogenic forces that alter the physical landscape are known to cause significant soil erosion, which has negative impact on surface water bodies, such as rivers, lakes/reservoirs, and coastal zones, and thus sediment control has become one of the central aspects of catchment management planning. The revised universal soil loss equation empirical model, erosion pins, and isotopic sediment core analyses were used to evaluate watershed erosion, stream bank erosion, and reservoir sediment accumulation rates for Ni Reservoir, in central Virginia. Land-use and land cover seems to be dominant control in watershed soil erosion, with barren land and human-disturbed areas contributing the most sediment, and forest and herbaceous areas contributing the least. Results show a 7 % increase in human development from 2001 (14 %) to 2009 (21.6 %), corresponding to an increase in soil loss of 0.82 Mg ha(-1) year(-1) in the same time period. (210)Pb-based sediment accumulation rates at three locations in Ni Reservoir were 1.020, 0.364, and 0.543 g cm(-2) year(-1) respectively, indicating that sediment accumulation and distribution in the reservoir is influenced by reservoir configuration and significant contributions from bedload. All three locations indicate an increase in modern sediment accumulation rates. Erosion pin results show variability in stream bank erosion with values ranging from 4.7 to 11.3 cm year(-1). These results indicate that urban growth and the decline in vegetative cover has increased sediment fluxes from the watershed and poses a significant threat to the long-term sustainability of the Ni Reservoir as urbanization continues to increase.

  7. Creating an Erosion Vulnerability Map for the Columbia River Basin to Determine Reservoir Susceptibility to Sedimentation Before and After Wildfires

    Science.gov (United States)

    Ren, J.; Robichaud, P. J. L.; Adam, J. C.

    2017-12-01

    Sedimentation is important issue to most rivers and reservoirs especially in watersheds with extensive agricultural or wildfire activity. These human and natural induced disturbances have the potential to increase runoff-induced erosion and sediment load to rivers; downstream sedimentation can decrease the life expectancy of reservoir and consequently the dam. This is particularly critical in snowmelt-dominant regions because, as rising temperatures reduce snowpack as a natural reservoir, humans will become more reliant on reservoir storage. In the Northwest U.S., the Columbia River Basin (CRB) has more than 60 dams, which were built for irrigation, hydropower, and flood control, all of which are affected by sediment to varying degrees. Determining what dams are most likely to be affected by sedimentation caused by post-fire erosion is important for future management of reservoirs, especially as climate change is anticipated to exacerbate wildfire and its impacts. The objective of this study is to create a sedimentation vulnerability map for reservoirs in the CRB. There are four attributes of a watershed that determine erosion potential; soil type, topography, vegetation (such as forests, shrubs, and grasslands), and precipitation (although precipitation was excluded in this analysis). In this study, a rating system was developed on a scale of 0-90 (with 90 having the greatest erosion potential). The different layers in a Graphical Information System were combined to create an erosion vulnerability map. Results suggest that areas with agriculture have more erosion without a wildfire but that forested areas are most vulnerable to erosion rates following a fire, particularly a high severity fire. Sedimentation in dams is a growing problem that needs to be addressed especially with the likely reduction in snowpack, this vulnerability map will help determine which reservoirs in the CRB are prone to high sedimentation. This information can inform managers where post

  8. Design philosophy and practice of asymmetrical 3D fracturing and random fracturing: A case study of tight sand gas reservoirs in western Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Jianchun Guo

    2015-03-01

    Full Text Available At present two technical models are commonly taken in tight gas reservoir stimulation: conventional massive fracturing and SRV fracturing, but how to select a suitable fracturing model suitable for reservoir characteristics is still a question waiting to be answered. In this paper, based on the analysis of geological characteristics and seepage mechanism of tight gas and shale gas reservoirs, the differences between stimulation philosophy of tight gas reservoirs and shale reservoirs are elucidated, and the concept that a suitable stimulation model should be selected based on reservoir geological characteristics and seepage mechanism aiming at maximally improving the seepage capability of a reservoir. Based on this concept, two fracturing design methods were proposed for two tight gas reservoirs in western Sichuan Basin: asymmetrical 3D fracturing design (A3DF for the middle-shallow Upper Jurassic Penglaizhen Fm stacked reservoirs in which the hydraulic fractures can well match the sand spatial distribution and seepage capability of the reservoirs; SRV fracturing design which can increase fracture randomness in the sandstone and shale laminated reservoirs for the 5th Member of middle-deep Upper Triassic Xujiahe Fm. Compared with that by conventional fracturing, the average production of horizontal wells fractured by A3DF increased by 41%, indicating that A3DF is appropriate for gas reservoir development in the Penglaizhen Fm; meanwhile, the average production per well of the 5th Member of the Xujiahe Fm was 2.25 × 104 m3/d after SRV fracturing, showing that the SRV fracturing is a robust technical means for the development of this reservoir.

  9. Long-Term Changes in Sediment and Nutrient Delivery from Conowingo Dam to Chesapeake Bay: Effects of Reservoir Sedimentation.

    Science.gov (United States)

    Zhang, Qian; Hirsch, Robert M; Ball, William P

    2016-02-16

    Reduction of suspended sediment (SS), total phosphorus (TP), and total nitrogen is an important focus for Chesapeake Bay watershed management. The Susquehanna River, the bay's largest tributary, has drawn attention because SS loads from behind Conowingo Dam (near the river's mouth) have been rising dramatically. To better understand these changes, we evaluated histories of concentration and loading (1986-2013) using data from sites above and below Conowingo Reservoir. First, observed concentration-discharge relationships show that SS and TP concentrations at the reservoir inlet have declined under most discharges in recent decades, but without corresponding declines at the outlet, implying recently diminished reservoir trapping. Second, best estimates of mass balance suggest decreasing net deposition of SS and TP in recent decades over a wide range of discharges, with cumulative mass generally dominated by the 75∼99.5th percentile of daily Conowingo discharges. Finally, stationary models that better accommodate effects of riverflow variability also support the conclusion of diminished trapping of SS and TP under a range of discharges that includes those well below the literature-reported scour threshold. Overall, these findings suggest that decreased net deposition of SS and TP has occurred at subscour levels of discharge, which has significant implications for the Chesapeake Bay ecosystem.

  10. Impact of sediments resuspension on metal solubilization and water quality during recurrent reservoir sluicing management

    Energy Technology Data Exchange (ETDEWEB)

    Frémion, Franck; Courtin-Nomade, Alexandra [Groupement de Recherche Eau Sol Environnement, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex (France); Bordas, François, E-mail: francois.bordas@unilim.fr [Groupement de Recherche Eau Sol Environnement, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex (France); Lenain, Jean-François [Groupement de Recherche Eau Sol Environnement, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex (France); Jugé, Philippe [CETU – ELMIS Ingénieries, Université François Rabelais, , 60 Rue du Plat d' Étain, 37000 Tours (France); Kestens, Tim [EDF – DPIH, Unité de Production Centre, 19 bis avenue de la Révolution, BP 406, 87012 Limoges Cedex (France); Mourier, Brice [Groupement de Recherche Eau Sol Environnement, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex (France)

    2016-08-15

    In dam contexts, sluicing operations can be performed to reestablish sediments continuity, as proposed by the EU Water Framework Directive, as well as to preserve the reservoirs' water storage capacity. Such management permits the rapid release of high quantities of reservoir sediments through the opening of dam bottom valves. This work aims to study the impact of such operation on the evolution of environmental physicochemical conditions notably changes in dissolved metallic elements concentrations (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) through field and laboratory investigations. Results were interpreted in terms of concentrations and fluxes, and compared with data collected on an annual basis regarding both suspended matter and metallic elements. The release of high quantities of sediments (4,500 tons dry weight in 24 h), with concentrations representing up to 300 times the inter-annual mean suspended sediments discharge, significantly modified water parameters, notably solid/liquid (S/L) ratio, pH and redox conditions. Despite the fact that they are mainly trapped in stable phases, a clear increase of the solubilized metals content was measured, representing up to 60 times the maximum values of current exploitation. This solubilization is related to desorption phenomena from sediments through changes in chemical equilibriums as highlighted by laboratory characterizations and experiments. These chemical modifications are mainly attributed to S/L ratio variations. Indeed, the low S/L ratios (≤ 1.3 g·L{sup −1}) measured in situ are typically the ones for which metals solubilization is the highest, as shown by laboratory experiments. Additional thermodynamic modeling highlighted that the decrease in pH measured during the operation favors the release of the free forms of metallic elements (Al and Cu), and decreases the OM complexation influence. These changes, either in term of physical conditions or speciation, increasing metals long term

  11. The Effect of Cirata Reservoir Sediment on Early Developmental Stage of Common Carp (Cyprinus carpio Embryo

    Directory of Open Access Journals (Sweden)

    Yuni Pujihastuti

    2009-07-01

    Full Text Available Sedimentation at Cirata reservoir may directly and indirectly influence fish particularly fish which have an adhesive characteristic at its early developmental stage such as common carp (Cyprinus carpio. Sample of sediment was collected from Cirata reservoir using Eikmand dredge at a depth of 80 m. The sample was subsequently centrifuged at 5500 rpm for 10 min. The supernatant obtained was then used for toxicity test on common carp at early developmental stage. In this test, four treatments were applied based on the concentration of sediment supernatant, namely: 0, 8.33, 16.60 and 24.90 %. The results showed that a higher sediment supernatant concentration resulted in lower egg yolk absorption rate, lower relative growth rate in length, lower egg yolk efficiency and higher egg and larval abnormality.  Higher sediment supernatant concentration also resulted in lower hatching percentage of common carp larva. The damage of eggs and larval morphologies in treatments with sediment supernatant was likely caused by the presence Pb and organic matters which act in synergy. Keywords :  sediment, Cirata, embryo, common carp   ABSTRAK Sedimentasi di Waduk Cirata secara langsung dan tidak langsung akan berpengaruh terhadap kehidupan ikan khususnya tahap awal perkembangan ikan yang bersifat adhesiveseperti ikan mas (Cyprinus carpio.  Sampel sedimen waduk Cirata diambil dengan Eikmand dredge pada kedalaman 80 m.  Hasil ekstrak di sentrifugasi dengan kecepatan 5500 rpm selama 10 menit untuk diambil air pori sedimennya.  Air pori digunakan sebagai bahan uji toksisitas terhadap perkembangan awal ikan mas dengan perlakuan 0; 8,33; 16,60 dan 24,90 %. Hasil uji toksisitas diperoleh bahwa semakin tinggi konsentrasi air pori dari sediment maka semakin rendah laju penyerapan kuning telur Laju pertumbuhan relatif panjang embrio pada berbagai konsentrasi juga diperoleh bahwa semakin tinggi konsentrasi air sedimen maka semakin rendah laju pertumbuhan relatif

  12. NH4+ adsorption and adsorption kinetics by sediments in a drinking water reservoir

    Directory of Open Access Journals (Sweden)

    Suna Hongyan

    2016-12-01

    Full Text Available The sorption isotherm and sorption kinetics of NH4+ by the Fen River reservoir sediment were investigated for a better understanding of the NH4+ sorption characteristics and parameters. The results showed that Q (adsorption content increased with the increase of Ceq (equilibrium concentration, sorption isotherms could be described by Freundlich equation (R2 from 0.97 to 0.99. Cation exchange capacity (CEC had a significant correlation with the parameters K and n (R2 was 0.85 and 0.95, respectively. The ENC0 (Ceq as Q was zero of S1, S2, S3 and S4 was 1.25, 0.57, 1.15 and 1.14 mg L-1, respectively, and they were less than the NH4+ concentrations in reservoir water. The sediments released NH4+ to the Fen River reservoir water and acted as a pollution source, in the form of complex and heterogeneous adsorbents. The NH4+ adsorption kinetic process was composed of ‘fast’ and ‘slow’ reaction patterns and could be fitted using both Elovich equation and Pseudo second-equation. More than one-step may be involved in the NH4+ sorption processes, and interior diffusion was not dominant ion action.

  13. Fingerprinting the main erosion processes delivering sediment to hillside reservoirs: Case of Kamech catchment in Cape Bon, Tunisia

    Science.gov (United States)

    Ben Slimane, A.; Raclot, D.; Evrard, O.; Sanaa, M.; Lefèvre, I.; Ahmadi, M.; Le Bissonnais, Y.

    2011-12-01

    About 74% of agricultural soils are affected by water erosion in Tunisia. This intense soil degradation threatens the sustainability of food production in the country. It also leads to the siltation of the numerous hillslide reservoirs that were constructed in the 1990s to protect downstream villages against floods and provide a source of water in cultivated areas. Very dense gully systems are observed in Tunisian agricultural land and in other Mediterranean regions, but their contribution to contemporary sediment supply to hillside reservoirs has not been quantified yet. Still, there is a need to quantify the sediment sources in this region in order to guide the implementation of erosion control measures. Sediment can be supplied by gully systems but it can also be provided by erosion of the superficial layer of cultivated soil. We propose a methodology to estimate the relative contribution of gully erosion vs. interrill erosion to the sediment accumulated in hillside reservoirs. This work was conducted in a pilot catchment (i.e., Kamech catchment, 263ha, Cape Bon, Tunisia) to define guidelines on the number and the location of sediment core samples to collect in the reservoirs, in order to provide relevant information on the evolution of sediment sources throughout the last two decades. Once validated, this methodology will be applied to other catchments of the Tunisian Ridge. We applied the sediment fingerprinting method, which consists in measuring conservative and stable properties in both sources and sinks of sediment to outline their origin. Sampling efforts were concentrated on the field surface (cropland and grassland), gullies and channel banks. Thirteen sediment cores were collected along an upstream-downstream transect across Kamech hillside reservoir, in order to estimate the contribution of each potential sediment source to the material accumulated at the outlet, and to investigate the potential spatial differences of sediment origin across the

  14. Spectral induced polarization of the three-phase system CO2 - brine - sand under reservoir conditions

    Science.gov (United States)

    Börner, Jana H.; Herdegen, Volker; Repke, Jens-Uwe; Spitzer, Klaus

    2017-01-01

    The spectral complex conductivity of a water-bearing sand during interaction with carbon dioxide (CO2) is influenced by multiple, simultaneous processes. These processes include partial saturation due to the replacement of conductive pore water with CO2 and chemical interaction of the reactive CO2 with the bulk fluid and the grain-water interface. We present a laboratory study on the spectral induced polarization of water-bearing sands during exposure to and flow-through by CO2. Conductivity spectra were measured successfully at pressures up to 30 MPa and 80 °C during active flow and at steady-state conditions concentrating on the frequency range between 0.0014 and 100 Hz. The frequency range between 0.1 and 100 Hz turned out to be most indicative for potential monitoring applications. The presented data show that the impact of CO2 on the electrolytic conductivity may be covered by a model for pore-water conductivity, which depends on salinity, pressure and temperature and has been derived from earlier investigations of the pore-water phase. The new data covering the three-phase system CO2-brine-sand further show that chemical interaction causes a reduction of surface conductivity by almost 20 per cent, which could be related to the low pH-value in the acidic environment due to CO2 dissolution and the dissociation of carbonic acid. The quantification of the total CO2 effect may be used as a correction during monitoring of a sequestration in terms of saturation. We show that this leads to a correct reconstruction of fluid saturation from electrical measurements. In addition, an indicator for changes of the inner surface area, which is related to mineral dissolution or precipitation processes, can be computed from the imaginary part of conductivity. The low frequency range between 0.0014 and 0.1 Hz shows additional characteristics, which deviate from the behaviour at higher frequencies. A Debye decomposition approach is applied to isolate the feature dominating the

  15. Next-Generation Sequencing Assessment of Eukaryotic Diversity in Oil Sands Tailings Ponds Sediments and Surface Water.

    Science.gov (United States)

    Aguilar, Maria; Richardson, Elisabeth; Tan, BoonFei; Walker, Giselle; Dunfield, Peter F; Bass, David; Nesbø, Camilla; Foght, Julia; Dacks, Joel B

    2016-11-01

    Tailings ponds in the Athabasca oil sands (Canada) contain fluid wastes, generated by the extraction of bitumen from oil sands ores. Although the autochthonous prokaryotic communities have been relatively well characterized, almost nothing is known about microbial eukaryotes living in the anoxic soft sediments of tailings ponds or in the thin oxic layer of water that covers them. We carried out the first next-generation sequencing study of microbial eukaryotic diversity in oil sands tailings ponds. In metagenomes prepared from tailings sediment and surface water, we detected very low numbers of sequences encoding eukaryotic small subunit ribosomal RNA representing seven major taxonomic groups of protists. We also produced and analysed three amplicon-based 18S rRNA libraries prepared from sediment samples. These revealed a more diverse set of taxa, 169 different OTUs encompassing up to eleven higher order groups of eukaryotes, according to detailed classification using homology searching and phylogenetic methods. The 10 most abundant OTUs accounted for > 90% of the total of reads, vs. large numbers of rare OTUs (< 1% abundance). Despite the anoxic and hydrocarbon-enriched nature of the environment, the tailings ponds harbour complex communities of microbial eukaryotes indicating that these organisms should be taken into account when studying the microbiology of the oil sands. © 2016 The Author(s) Journal of Eukaryotic Microbiology © 2016 International Society of Protistologists.

  16. Peculiarities of Particulate 137Cs transport and sedimentation in Kiev reservoir

    International Nuclear Information System (INIS)

    Voitsekhovitch, O.; Kanivets, V.; Biliy, I.; Laptev, G.; Sansone, U.; Riccardi, M.

    1996-01-01

    The paper presents the data on Chernobyl radiocesium bound to suspended matter and bottom sediments at different locations along the sampling rout from Rivers of Chernobyl zone to upper Reservoirs of Dnieper River. These data were collected as a result of joint Ukrainian-Italian field exercises in the frame of ECP-3 project. It was found out that total 137 Cs concentration in the water column decreases downstream the Chernobyl zone while K D in situ values substantially increase with approach to the Kiev HPS dam. Taking account of uniform hydro-chemical conditions in investigated area one can explain this phenomenon only by gradual elimination of coarse sandy component with low sorption capacity from the river flow by sedimentation. In contrary, radiocesium which is selectively sorbed and fixed on fine clay particles travels much longer distances and ensures observed higher K D in situ values. This conclusion is supported by the analyses of three sediment cores taken in upper, middle and lower parts of Kiev reservoir

  17. Metal quantification in water and sediment samples of billings reservoir by SR-TXRF

    International Nuclear Information System (INIS)

    Sampaio, Sergio Arnaud; Moreira, Silvana; Vives, Ana Elisa Sirito de

    2007-01-01

    Billings is the largest reservoir water of the metropolitan Sao Paulo area, with approximately 100km 2 of water. Its basin hydrographic occupies more than 500km 2 in six cities. It concentrates the largest industrial park of South America and only its margins are busy for almost a million inhabitants. The quality of its waters is, therefore, constant of concern of the whole society. In this work the Synchrotron Radiation Total Reflection X Ray Fluorescence (SR-TXRF) is applied for the identification and quantification of metals in waters and sediments of the Billings dam. A comparison of the levels of metals found with the maximum permissive limits established by the Brazilian legislation was made. The purpose of social context is to contribute for the preservation of the local springs and the rational use of its waters. For the field work they were chosen 19 collection points, included the margins and the central portion of the dam, in agreement with similar approaches the those adopted by the Company of Technology of Environmental Sanitation of Sao Paulo State (CETESB).The water and sediment samples, as well as the certified and standard samples, were analyzed at Brazilian Synchrotron Light Laboratory (LNLS), Campinas, SP, Brazil. Results indicate that the water and the sediments of the reservoir have concentrations above the legal limits. (author)

  18. Metal quantification in water and sediment samples of billings reservoir by SR-TXRF

    Energy Technology Data Exchange (ETDEWEB)

    Sampaio, Sergio Arnaud; Moreira, Silvana [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo]. E-mails: silvana@fec.unicamp.br; sergioarnaud@hotmail.com; Vives, Ana Elisa Sirito de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br

    2007-07-01

    Billings is the largest reservoir water of the metropolitan Sao Paulo area, with approximately 100km{sup 2} of water. Its basin hydrographic occupies more than 500km{sup 2} in six cities. It concentrates the largest industrial park of South America and only its margins are busy for almost a million inhabitants. The quality of its waters is, therefore, constant of concern of the whole society. In this work the Synchrotron Radiation Total Reflection X Ray Fluorescence (SR-TXRF) is applied for the identification and quantification of metals in waters and sediments of the Billings dam. A comparison of the levels of metals found with the maximum permissive limits established by the Brazilian legislation was made. The purpose of social context is to contribute for the preservation of the local springs and the rational use of its waters. For the field work they were chosen 19 collection points, included the margins and the central portion of the dam, in agreement with similar approaches the those adopted by the Company of Technology of Environmental Sanitation of Sao Paulo State (CETESB).The water and sediment samples, as well as the certified and standard samples, were analyzed at Brazilian Synchrotron Light Laboratory (LNLS), Campinas, SP, Brazil. Results indicate that the water and the sediments of the reservoir have concentrations above the legal limits. (author)

  19. Extreme methane emissions from a Swiss hydropower reservoir: contribution from bubbling sediments.

    Science.gov (United States)

    Delsontro, Tonya; McGinnis, Daniel F; Sobek, Sebastian; Ostrovsky, Ilia; Wehrli, Bernhard

    2010-04-01

    Methane emission pathways and their importance were quantified during a yearlong survey of a temperate hydropower reservoir. Measurements using gas traps indicated very high ebullition rates, but due to the stochastic nature of ebullition a mass balance approach was crucial to deduce system-wide methane sources and losses. Methane diffusion from the sediment was generally low and seasonally stable and did not account for the high concentration of dissolved methane measured in the reservoir discharge. A strong positive correlation between water temperature and the observed dissolved methane concentration enabled us to quantify the dissolved methane addition from bubble dissolution using a system-wide mass balance. Finally, knowing the contribution due to bubble dissolution, we used a bubble model to estimate bubble emission directly to the atmosphere. Our results indicated that the total methane emission from Lake Wohlen was on average >150 mg CH(4) m(-2) d(-1), which is the highest ever documented for a midlatitude reservoir. The substantial temperature-dependent methane emissions discovered in this 90-year-old reservoir indicate that temperate water bodies can be an important but overlooked methane source.

  20. Hydraulic characteristics and sediment generation on slope erosion in the Three Gorges Reservoir Area, China

    Directory of Open Access Journals (Sweden)

    Qian Feng

    2016-09-01

    Full Text Available Hydrological processes play important roles in soil erosion processes of the hillslopes. This study was conducted to investigate the hydrological processes and the associated erosional responses on the purple soil slope. Based on a comprehensive survey of the Wangjiaqiao watershed in the Three Gorges Reservoir, four typical slope gradients (5°, 10°, 15°and 20° were applied to five rainfall intensities (0.6, 1.1, 1.61, 2.12 and 2.54 mm·min-1. The results showed that both surface and subsurface runoff varied greatly depending on the rainfall intensity and slope gradient. Surface runoff volume was 48.1 to 280.1 times of that for subsurface runoff. The critical slope gradient was about 10°. The sediment yield rate increased with increases in both rainfall intensity and slope gradient, while the effect of rainfall intensity on the sediment yield rate was greater than slope gradient. There was a good linear relationship between sediment yield rate and Reynolds numbers, flow velocity and stream power, while Froude numbers, Darcy-Weisbach and Manning friction coefficients were not good hydraulic indicators of the sediment yield rate of purple soil erosion. Among the three good indicators (Re, v and w, stream power was the best predictor of sediment yield rate (R2 = 0.884. Finally, based on the power regression relationship between sediment yield rate, runoff rate, slope gradient and rainfall intensity, an erosion model was proposed to predict the purple soil erosion (R2 = 0.897. The results can help us to understand the relationship between flow hydraulics and sediment generation of slope erosion and offer useful data for the building of erosion model in purple soil.

  1. Assessment of natural radioactivity levels and identification of minerals in Brahmaputra (Jamuna) river sand and sediment, Bangladesh

    International Nuclear Information System (INIS)

    Khalil, Md. Ibrahim; Majumder, Ratan Kumar; Kabir, Md. Zafrul; Deeba, Farah; Khan, Md. Nazrul Islam; Ali, Md. Idris; Paul, Debasish; Haydar, Md. Abu; Islam, Syed Mohammad Azharul

    2016-01-01

    Distribution of the natural radionuclides ( 238 U, 232 Th, and 40 K) and their specific activities in sands and sediments of the Brahmaputra (Jamuna) river of Bangladesh together with mineral characteristics has been studied to assess the radiation levels as well as to develop a baseline database for comparison in the future in case of any change in the area under study due to anthropogenic activities. The radiological parameters of natural radioactivity were assessed calculating the radium equivalent activity, hazard index, the absorbed dose rate, and annual effective dose. The average activity concentrations of 226 Ra ( 238 U), 232 Th, and 40 K in sand and sediment were found to be 59 ± 2 and 60 ± 2 Bq/kg, 113 ± 5 and 135 ± 5 Bq/kg, and 983 ± 42 and 1002 ± 43 Bq/kg, respectively. The calculated average absorbed dose rate and annual effective dose were found to be 150 nGy/h and 0.18 mSv/year respectively. These high values are associated with mineral content of the sediment. X-ray diffraction peaks of sand and sediment samples identify quartz, feldspar, rutile, zircon, monazite, uranium fluoride, hematite, kyanite, and uranium arsenide minerals to be present in the samples. (author)

  2. Chemical and physical characteristics of water and sediment in Scofield Reservoir, Carbon County, Utah

    Science.gov (United States)

    Waddell, Kidd M.; Darby, D.W.; Theobald, S.M.

    1985-01-01

    Evaluations based on the nutrient content of the inflow, outflow, water in storage, and the dissolved-oxygen depletion during the summer indicate that the trophic state of Scofield Reservoir is borderline between mesotrophic and eutrophic and may become highly eutrophic unless corrective measures are taken to limit nutrient inflow.Sediment deposition in Scofield Reservoir during 1943-79 is estimated to be 3,000 acre-feet, and has decreased the original storage capacity of the reservoir by 4 percent. The sediment contains some coal, and age dating of those sediments (based on the radioisotope lead-210) indicates that most of the coal was deposited prior to about 1950.Scofield Reservoir is dimictic, with turnovers occurring in the spring and autumn. Water in the reservoir circulates completely to the bottom during turnovers. The concentration of dissolved oxygen decreases with depth except during parts of the turnover periods. Below an altitude of about 7,590 feet, where 20 percent of the water is stored, the concentration of dissolved oxygen was less than 2 milligrams per liter during most of the year. During the summer stratification period, the depletion of dissolved oxygen in the deeper layers is coincident with supersaturated conditions in the shallow layers; this is attributed to plant photosynthesis and bacterial respiration in the reservoir.During October 1,1979-August 31,1980, thedischargeweighted average concentrations of dissolved solids was 195 milligrams per liter in the combined inflow from Fish, Pondtown, and Mud Creeks, and was 175 milligrams per liter in the outflow (and to the Price River). The smaller concentration in the outflow was due primarily to precipitation of calcium carbonate in the reservoir about 80 percent of the decrease can be accounted for through loss as calcium carbonate.The estimated discharge-weighted average concentration of total nitrogen (dissolved plus suspended) in the combined inflow of Fish, Pondtown, and Mud Creeks was 1

  3. Sources of heavy metals in surface sediments and an ecological risk assessment from two adjacent Plateau reservoirs.

    Directory of Open Access Journals (Sweden)

    Binbin Wu

    Full Text Available The concentrations of heavy metals (mercury (Hg, cadmium (Cd, lead (Pb, chromium (Cr, copper (Cu and arsenic (As in surface water and sediments were investigated in two adjacent drinking water reservoirs (Hongfeng and Baihua Reservoirs on the Yunnan-Guizhou Plateau in Southwest China. Possible pollution sources were identified by spatial and statistical analyses. For both reservoirs, Cd was most likely from industrial activities, and As was from lithogenic sources. For the Hongfeng Reservoir, Pb, Cr and Cu might have originated from mixed sources (traffic pollution and residual effect of former industrial practices, and the sources of Hg included the inflows, which were different for the North (industrial activities and South (lithogenic origin Lakes, and atmospheric deposition resulting from coal combustion. For the Baihua Reservoir, the Hg, Cr and Cu were primarily derived from industrial activities, and the Pb originated from traffic pollution. The Hg in the Baihua Reservoir might also have been associated with coal combustion pollution. An analysis of ecological risk using sediment quality guidelines showed that there were moderate toxicological risks for sediment-dwelling organisms in both reservoirs, mainly from Hg and Cr. Ecological risk analysis using the Hakanson index suggested that there was a potential moderate to very high ecological risk to humans from fish in both reservoirs, mainly because of elevated levels of Hg and Cd. The upstream Hongfeng Reservoir acts as a buffer, but remains an important source of Cd, Cu and Pb and a moderately important source of Cr, for the downstream Baihua Reservoir. This study provides a replicable method for assessing aquatic ecosystem health in adjacent plateau reservoirs.

  4. Characterization of Suspended-Sediment Loading to and from John Redmond Reservoir, East-Central Kansas, 2007-2008

    Science.gov (United States)

    Lee, Casey J.; Rasmussen, Patrick P.; Ziegler, Andrew C.

    2008-01-01

    Storage capacity in John Redmond Reservoir is being lost to sedimentation more rapidly than in other federal impoundments in Kansas. The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, initiated a study to characterize suspended-sediment loading to and from John Redmond Reservoir from February 21, 2007, through February 21, 2008. Turbidity sensors were installed at two U.S. Geological Survey stream gages upstream (Neosho River near Americus and the Cottonwood River near Plymouth) and one stream gage downstream (Neosho River at Burlington) from the reservoir to compute continuous, real-time (15-minute) measurements of suspended-sediment concentration and loading. About 1,120,000 tons of suspended-sediment were transported to, and 100,700 tons were transported from John Redmond Reservoir during the study period. Dependent on the bulk density of sediment stored in the reservoir, 5.0 to 1.4 percent of the storage in the John Redmond conservation pool was lost during the study period, with an average deposition of 3.4 to 1.0 inches. Nearly all (98-99 percent) of the incoming sediment load was transported during 9 storms which occurred 25 to 27 percent of the time. The largest storm during the study period (peak-flow recurrence interval of about 4.6-4.9 years) transported about 37 percent of the sediment load to the reservoir. Suspended-sediment yield from the unregulated drainage area upstream from the Neosho River near Americus was 530 tons per square mile, compared to 400 tons per square mile upstream from the Cottonwood River near Plymouth. Comparison of historical (1964-78) to current (2007) sediment loading estimates indicate statistically insignificant (99 percent) decrease in sediment loading at the Neosho River at Burlington. Ninety-percent confidence intervals of streamflow-derived estimates of total sediment load were 7 to 21 times larger than turbidity-derived estimates. Results from this study can be used by natural resource

  5. Soil erosion and sediment delivery issues in a large hydro-electric power reservoir catchment, Ethiopia

    Science.gov (United States)

    Nebiyu, Amsalu; Dume, Bayu; Bode, Samuel; Ram, Hari; Boeckx, Pascal

    2017-04-01

    Land degradation and associated processes such as gullying, flooding and sedimentation, are among the developmental challenges in many countries and HEP reservoirs in the Gilgel Gibe catchment, Ethiopia, are under threat from siltation. Soil erosion is one of the biggest global environmental problems resulting in both on-site and offsite effects which have economic implications and an essential actor in assessing ecosystem health and function. Sediment supply in a catchment is heterogeneous in time and space depending on climate, land use and a number of landscape characteristics such as slope, topography, soil type, vegetation and drainage conditions. In the Ethiopian highlands, sediment delivery depends on discharge, the onset of rainfall, land use and land cover, which varies between rainfall seasons. There is also a variation among catchments in suspended sediment concentration due to the variation in the catchments characteristics in Ethiopia. Rainfall-runoff relationship, sediment production and delivery to rivers or dams is variable and poorly understood; due to heterogeneous lithology; various climatic conditions across small spatial scales; land use and land management practices in Ethiopia. Spatial variation in sediment yield in Africa varies to differences in seismic activity, topography, vegetation cover and annual runoff depth. In the Gilgel-Gibe catchment, the annual sediment load of the Gilgel-Gibe River has been estimated to be about 4.5×107 tons taking the contribution of sheet erosion alone. Also, the suspended sediment yield of the tributaries in Gilgel-Gibe catchment has been estimated to be in the range of 0.4-132.1 tons per hectare per year. The soil loss due to landslide alone in the past 20 years in the catchment was about 11 t/ha/yr. Heavy rainfall, bank erosion and river incisions have been indicated as the main triggering factors for landslides and the associated sediment delivery in the Gilgel-Gibe catchment. Approaches for catchment

  6. Environmental effects of storage preservation practices: controlled flushing of fine sediment from a small hydropower reservoir.

    Science.gov (United States)

    Espa, Paolo; Castelli, Elena; Crosa, Giuseppe; Gentili, Gaetano

    2013-07-01

    Sediment flushing may be effective in mitigating loss of reservoir storage due to siltation, but flushing must be controlled to limit the impact on the downstream environment. A reliable prediction of the environmental effects of sediment flushing is hindered by the limited scientific information currently available. Consequently, there may be some controversy as regards to management decisions, planning the work, and monitoring strategies. This paper summarizes the main results of a monitoring campaign on the stream below a small alpine hydropower reservoir subjected to annual flushing between 2006 and 2009. The removed sediment was essentially silt, and the suspended solid concentration (SSC) of the discharged water was controlled to alleviate downstream impact. Control was achieved through hydraulic regulation and mechanical digging, alternating daytime sediment evacuation, and nocturnal clear water release. The four operations lasted about two weeks each and had an average SSC of about 4 g L(-1). Maximum values of SSC were generally kept below 10 g L(-1). Downstream impact was quantified through sampling of fish fauna (brown trout) and macroinvertebrate in the final reach of the effluent stream. The benthic community was severely impaired by the flushing operations, but recovered to pre-flushing values in a few months. As expected, the impact on brown trout was heavier on juveniles. While data biasing due to fish removal and re-stocking cannot be ruled out, the fish community seems to have reached a state of equilibrium characterized by a lower density than was measured before the flushing operations.

  7. Metal and trace element assessment of sediments from Guarapiranga reservoir, Sao Paulo State, by neutron activation analysis

    International Nuclear Information System (INIS)

    Guimaraes, Guilherme M.; Favaro, Deborah I.T.; Franklin, Robson L.; Ferreira, Francisco J.; Bevilacqua, Jose E.

    2009-01-01

    Guarapiranga Reservoir is extremely important due to the fact that it is one of the main water reservoirs for South America's largest city, Sao Paulo, Brazil. Guarapiranga Basin is located within the Metropolitan Region of Sao Paulo - RMSP, and occupies an area of approximately 630 km 2 , and the reservoir itself is located in the northern part of the basin occupying approximately 26 km 2 . This reservoir is characterized by environmental impacts from urban invasion, industrial and sewage wastes, all of which seriously affect its water quality. Due to its vulnerability CETESB (Environmental Control Agency of the Sao Paulo State) regularly monitors the contamination levels of waters and once a year sediment samples. In order to better understand geochemical and environmental processes and their possible changes due to anthropogenic activities trace metals analyses and their distribution in sediments are commonly undertaken. The present study reports results concerning the distribution of some major (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Hg, Rb, Sb, Sc, Ta, Tb, Th, U and Zn) and rare earth (Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) elements in sediments from the Guarapiranga Reservoir. Multielementar analysis was carried out by instrumental neutron activation analysis (INAA). Multielemental concentrations in the sediment samples were compared to NASC (North American Shale Composite) values. The concentration values for metals As, Cr and Zn in the sediment samples were compared to the Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values) and adopted by CETESB. (author)

  8. Stratigraphic framework of sediment-starved sand ridges on a mixed siliciclastic/carbonate inner shelf; west-central Florida

    Science.gov (United States)

    Edwards, J.H.; Harrison, S.E.; Locker, S.D.; Hine, A.C.; Twichell, D.C.

    2003-01-01

    Seismic reflection profiles and vibracores have revealed that an inner shelf, sand-ridge field has developed over the past few thousand years situated on an elevated, broad bedrock terrace. This terrace extends seaward of a major headland associated with the modern barrier-island coastline of west-central Florida. The overall geologic setting is a low-energy, sediment-starved, mixed siliciclastic/carbonate inner continental shelf supporting a thin sedimentary veneer. This veneer is arranged in a series of subparallel, shore-oblique, and to a minor extent, shore-parallel sand ridges. Seven major facies are present beneath the ridges, including a basal Neogene limestone gravel facies and a blue-green clay facies indicative of dominantly authigenic sedimentation. A major sequence boundary separates these older units from Holocene age, organic-rich mud facies (marsh), which grades upward into a muddy sand facies (lagoon or shallow open shelf/seagrass meadows). Cores reveal that the muddy shelf facies is either in sharp contact or grades upward into a shelly sand facies (ravinement or sudden termination of seagrass meadows). The shelly sand facies grades upward to a mixed siliciclastic/carbonate facies, which forms the sand ridges themselves. This mixed siliciclastic/carbonate facies differs from the sediment on the beach and shoreface, suggesting insignificant sediment exchange between the offshore ridges and the modern coastline. Additionally, the lack of early Holocene, pre-ridge facies in the troughs between the ridges suggests that the ridges themselves do not migrate laterally extensively. Radiocarbon dating has indicated that these sand ridges can form relatively quickly (???1.3 ka) on relatively low-energy inner shelves once open-marine conditions are available, and that frequent, high-energy, storm-dominated conditions are not necessarily required. We suggest that the two inner shelf depositional models presented (open-shelf vs. migrating barrier-island) may

  9. Simulation of Sediment Transport Caused by Landslide at Nanhua Reservoir Watershed in Southern Taiwan

    Science.gov (United States)

    Lee, Ming-Hsi; Huang, Cong-Gi; Lin, Huan-Hsuan

    2016-04-01

    As a result of heavy rainfall, steep topography, young and weak geological formations, earthquakes, loose soils, slope land cultivation and other human disturbance, much area in Taiwan are prone to the occurrence of disastrous mass movements such as landslides and sediment disasters. During recent years, the extreme rainfall events brought huge amounts of rainfall and triggered severe changes in watershed environments. Typhoon Morakot in August 2009 caused severe landslides, debris flow, flooding and sediment disasters induced by record-break rainfall. The maximum rainfall of mountain area in Chiayi, Tainan, Kaohsiung and Pingtung County were over 2,900 mm. The study area is located at Nanhua reservoir watershed in southern Taiwan. The numerical model (HEC-RAS 4.1 and FLO-2D) will be used to simulate the sediment transport caused by landslide and the study will find out the separating location of erosion and deposition in the river, the danger area of riverbank, and the safety of the river terrace village under the return period of 50-year, 100-year and 200-year (such as Typhoon Morakot). The results of this study can provide for the disaster risk management of administrative decisions to lessen the impacts of natural hazards and may also be useful for time-space variation of sediment disasters caused by Climate Change.

  10. Assessment of metal concentrations in sediment samples from Billings Reservoir, Rio Grande tributary, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Bostelmann, Eleine

    2006-01-01

    The present study chemically characterized sediment samples from the Billings reservoir, Rio Grande tributary, in the Metropolitan region of Sao Paulo, by determining metal concentration and other elements of interest. The chosen chemical parameters for this characterization were Aluminum, Arsenic, Barium, Cadmium, Copper, Chromium, Iron, Lead, Manganese, Mercury, Nickel, Selenium and Zinco. These parameters are also used in the water quality index, with the exception of Selenium. The concentrations were determined through different analytical techniques such as atomic absorption spectrometry (FAAS, GFAAS and CVAAS), optical emission spectrometry (ICP OES) and neutron activation analysis. These analytical methodologies were assessed for precision, accuracy and detection and/or quantification limits for the sediment elements in question. Advantages and disadvantages of each technique for each element and its concentration were also discussed. From these assessments the most adequate technique was selected for the routine analysis of sediment samples for each element concentration determination. This assessment verified also that digestion in a closed microwave system with nitric acid is efficient for the evaluation of extracted metals of environmental interest. The analytical techniques chosen were equally efficient for metals determination. In the case of Cd and Pb, the FAAS technique was selected due to better results than ICP OES, as it does not present matrix interference. The concentration values obtained for metals As, Cd, Cu, Cr, Hg, Ni, Pb and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) TEL and PEL values. (author)

  11. Assessment of metal concentrations in sediment samples from Billings reservoir, Rio Grande tributary, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Bostelmann, Eleine

    2006-01-01

    The present study chemically characterized sediment samples from the Billings reservoir, Rio Grande tributary, in the Metropolitan region of Sao Paulo, by determining metal concentration and other elements of interest. The chosen chemical parameters for this characterization were Aluminum, Arsenic, Barium, Cadmium, Copper, Chromium, Iron, Lead, Manganese, Mercury, Nickel, Selenium and Zinc. These parameters are also used in the water quality index, with the exception of Selenium. The concentrations were determined through different analytical techniques such as atomic absorption spectrometry (FAAS, GFAAS and CVAAS), optical emission spectrometry (ICP OES) and neutron activation analysis. These analytical methodologies were assessed for precision, accuracy and detection and/or quantification limits for the sediment elements in question. Advantages and disadvantages of each technique for each element and its concentration were also discussed. From these assessment the most adequate technique was selected for the routine analysis of sediment samples for each element concentration determination. This assessment verified also that digestion in a closed microwave system with nitric acid is efficient for the evaluation of extracted metals of environmental interest. The analytical techniques chosen were equally efficient for metals determination. In the case of Cd and Pb, the FAAS technique was selected due to better results than ICP OES, as it does not present matrix interference. The concentration values obtained for metals As, Cd, Cu, Cr, Hg, Ni, Pb and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) TEL and PEL values. (author)

  12. Sorption kinetics of Cs and Sr in sediments of a Savannah River Site reservoir

    International Nuclear Information System (INIS)

    Stephens, J.A.

    1997-07-01

    Laboratory measurements of the sorption and desorption of 134 Cs and 85 Sr to sediments were conducted. These sediments were sampled from the profundal zone of Par Pond at the Savannah River Site, Aiken, South Carolina. The isotopes 134 Cs and 85 Sr were used to trace the sorption properties of the main contaminants found in the reservoir which are 137 Cs and 90 Sr respectively. The sorption behavior of these two elements was studied using spiked sediment/water slurries of a known mass to volume ratio. The results reveal that Sr undergoes significant reversible sorption while a fraction of Cs irreversibly sorbs to the sediment. The calculated distribution coefficient Kd at equilibrium was (3 ± 0.6) x 10 3 for 134 Cs after 60 d and (1 ± 0.2) x 10 3 for 85 Sr after 7 d at pH ∼ 6 and slurry ratio of 1:1000 g/ml. The K d for 134 Cs ranged from 2 x 10 2 to 3 x 10 4 depending on pH and conductivity. The 85 Sr reached equilibrium in a few days, while 134 Cs reached an apparent equilibrium in 1--2 months. The K d for 134 Cs was a function of the slurry ratio, pH, conductivity, and contact time. These factors were interrelated since the sediments released ions to the slurry mixture which decreased the pH and increased the conductivity. A sorption isotherm measured for 134 Cs was linear at water concentrations from 60 mBq/ml to 20 Bq/ml. A kinetic model was proposed to describe the basic sorption of 134 Cs to Par Pond sediments under homogeneous laboratory conditions

  13. 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.

  14. Recycling of Clay Sediments for Geopolymer Binder Production. A New Perspective for Reservoir Management in the Framework of Italian Legislation: The Occhito Reservoir Case Study.

    Science.gov (United States)

    Molino, Bruno; De Vincenzo, Annamaria; Ferone, Claudio; Messina, Francesco; Colangelo, Francesco; Cioffi, Raffaele

    2014-07-31

    Reservoir silting is an unavoidable issue. It is estimated that in Italy, the potential rate of silting-up in large reservoirs ranges from 0.1% to 1% in the presence of wooded river basins and intensive agricultural land use, respectively. In medium and small-sized reservoirs, these values vary between 0.3% and 2%. Considering both the types of reservoirs, the annual average loss of storage capacity would be of about 1.59%. In this paper, a management strategy aimed at sediment productive reuse is presented. Particularly, the main engineering outcomes of an extensive experimental program on geopolymer binder synthesis is reported. The case study deals with Occhito reservoir, located in Southern Italy. Clay sediments coming from this silted-up artificial lake were characterized, calcined and activated, by means of a wide set of alkaline activating solutions. The results showed the feasibility of this recovery process, optimizing a few chemical parameters. The possible reuse in building material production (binders, precast concrete, bricks, etc. ) represents a relevant sustainable alternative to landfill and other more consolidated practices.

  15. Recycling of Clay Sediments for Geopolymer Binder Production. A New Perspective for Reservoir Management in the Framework of Italian Legislation: The Occhito Reservoir Case Study

    Directory of Open Access Journals (Sweden)

    Bruno Molino

    2014-07-01

    Full Text Available Reservoir silting is an unavoidable issue. It is estimated that in Italy, the potential rate of silting-up in large reservoirs ranges from 0.1% to 1% in the presence of wooded river basins and intensive agricultural land use, respectively. In medium and small-sized reservoirs, these values vary between 0.3% and 2%. Considering both the types of reservoirs, the annual average loss of storage capacity would be of about 1.59%. In this paper, a management strategy aimed at sediment productive reuse is presented. Particularly, the main engineering outcomes of an extensive experimental program on geopolymer binder synthesis is reported. The case study deals with Occhito reservoir, located in Southern Italy. Clay sediments coming from this silted-up artificial lake were characterized, calcined and activated, by means of a wide set of alkaline activating solutions. The results showed the feasibility of this recovery process, optimizing a few chemical parameters. The possible reuse in building material production (binders, precast concrete, bricks, etc. represents a relevant sustainable alternative to landfill and other more consolidated practices.

  16. Metal and trace element sediment assessment from Salto Grande reservoir, Sao Paulo state, Brazil, by instrumental neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Walace A.A., E-mail: walace@usp.br [Setor de Analises Toxicologicas. CETESB, Sao Paulo, SP (Brazil); Favaro, Deborah I.T., E-mail: defavaro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao com Neutrons

    2011-07-01

    The Salto Grande Reservoir is used for electric generation, irrigation, fish farming, recreation and water supply for the region's cities. The reservoir belongs to the city of Americana, located in on the eastern region of Sao Paulo State, Brazil. It belongs to the Piracicaba River Hydrographic Basin, the second most important economic and populated region and one of the most polluted areas in the State. This basin is located in a highly industrialized and agricultural region. Due to urban, industrial and agricultural activities as well as sewage wastes the water and sediments of this reservoir and surroundings are extremely contaminated, mainly by metals, according to CETESB (Environmental Control Agency of the Sao Paulo State). In order to obtain better information about its sediment contamination the present study reports results of the concentration of some major (Ca, Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Rb, Sb, Se, Ta, Th, U, Zn and rare earth (Ce, Eu, La, Lu, Nd, Sc, Sm, Tb and Yb)) elements in sediments and Cd, Cr, Cu, Ni and Pb concentration in sediments and water from the Salto Grande Reservoir. Multielementar analysis was carried out by Instrumental Neutron Activation Analysis (INAA). Multielemental concentrations in the sediment samples were compared to NASC (North American Shale Composite) values. The concentration values for metals As, Cd, Cr, Cu, Pb, Ni and Zn were compared to the Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL) and adopted by CETESB, (author)

  17. Comparison of total Hg results in sediment samples from Rio Grande reservoir determine by NAA and CV AAS

    International Nuclear Information System (INIS)

    Franklin, Robson L.

    2011-01-01

    The Rio Grande reservoir is located in the Metropolitan area of Sao Paulo and it is used for recreation purposes and as source water for drinking water production. During the last decades has been detected mercury contamination in the sediments of this reservoir, mainly in the eastern part, near the main affluent of the reservoir, in the Rio Grande da Serra and Ribeirao Pires counties. In the present study bottom sediment samples were collected in four different sites into four sampling campaigns during the period of September 2008 to January 2010. The samples were dried at room temperature, ground and passed through a 2 mm sieve. Total Hg determination in the sediment samples was carried out by two different analytical techniques: neutron activation analysis (NAA) and cold vapor atomic absorption spectrometry (CV AAS). The methodology validation, in terms of precision and accuracy, was performed by reference materials, and presented a recovery of 83 to 108%. The total Hg results obtained by both analytical techniques ranged from 3 to 71 mg kg-1 and were considered similar by statistical analysis, even though NAA technique furnishes the total concentration while CV AAS using the 3015 digestion procedure characterizes only the bioavailable Hg. These results confirm that both analytical techniques were suitable to detect the Hg concentration levels in the Rio Grande sediments studied. The Hg levels in the sediment of the Rio Grande reservoir confirm the anthropogenic origin for this element in this ecosystem. (author)

  18. Metal and trace element sediment assessment from Salto Grande reservoir, Sao Paulo state, Brazil, by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Soares, Walace A.A.; Favaro, Deborah I.T.

    2011-01-01

    The Salto Grande Reservoir is used for electric generation, irrigation, fish farming, recreation and water supply for the region's cities. The reservoir belongs to the city of Americana, located in on the eastern region of Sao Paulo State, Brazil. It belongs to the Piracicaba River Hydrographic Basin, the second most important economic and populated region and one of the most polluted areas in the State. This basin is located in a highly industrialized and agricultural region. Due to urban, industrial and agricultural activities as well as sewage wastes the water and sediments of this reservoir and surroundings are extremely contaminated, mainly by metals, according to CETESB (Environmental Control Agency of the Sao Paulo State). In order to obtain better information about its sediment contamination the present study reports results of the concentration of some major (Ca, Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Rb, Sb, Se, Ta, Th, U, Zn and rare earth (Ce, Eu, La, Lu, Nd, Sc, Sm, Tb and Yb)) elements in sediments and Cd, Cr, Cu, Ni and Pb concentration in sediments and water from the Salto Grande Reservoir. Multielementar analysis was carried out by Instrumental Neutron Activation Analysis (INAA). Multielemental concentrations in the sediment samples were compared to NASC (North American Shale Composite) values. The concentration values for metals As, Cd, Cr, Cu, Pb, Ni and Zn were compared to the Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL) and adopted by CETESB, (author)

  19. Sedimentological and Geomorphological Effects of Reservoir Flushing: The Cachi Reservoir, Costa Rica, 1996

    DEFF Research Database (Denmark)

    Brandt, Anders; Swenning, Joar

    1999-01-01

    Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs......Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs...

  20. Metal and trace element sediment assessment from Guarapiranga reservoir, Alto Tiete Basin, Sao Paulo, SP, Brazil

    International Nuclear Information System (INIS)

    Guimaraes, Guilherme Moura

    2011-01-01

    The Guarapiranga Reservoir, located in Sao Paulo metropolitan region, Brazil, is responsible for supplying about 20% of the entire population's water needs of this region or approximately 3.7 million people. However, this system has shown significant degradation in water quality, due to untreated domestic sewage and industrial effluents. In this study sediment samples were collected at five points along the reservoir and total concentration of some major (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Hg, Rb, Sb, Sc, Ta, Tb, Th, U, V and Zn) and rare earth (Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) elements were determined by instrumental neutron activation analysis (INAA). By inductively coupled plasma optical emission spectrometry (ICP OES) the concentrations of Al, Ba, Be, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Ti, V e Zn were determined after digestion procedure following US EPA 3051 methodology. The concentrations of metals Cd and Pb were determined by graphite furnace atomic absorption spectrometry (GFAAS) and total Hg by cold vapor atomic absorption spectrometry (CVAAS). Methodology validation according to precision and accuracy was performed by reference materials analyses for the three different analytical techniques used. Multielemental results obtained by INAA were compared to NASC (North American Shale Composite), Upper Continental Crust (UCC) and soil from Guarapiranga park values. The Enrichment Factor (EF) and Geo accumulation Index (Igeo) were also evaluated for these data. Metal concentration results by ICP OES and AAS in the samples were compared to the TEL and PEL oriented values established by the Canadian Council of Ministers of the Environment and also adopted by CETESB (Environmental Protection Agency of the Sao Paulo State). The results were also compared to regional reference values (VRR) of limnic sediments from the Alto Tiete Basin. From these data an assessment of metal and trace element accumulated in the sediments from the

  1. Advanced Reservoir Characterization and Development through High-Resolution 3C3D Seismic and Horizontal Drilling: Eva South Marrow Sand Unit, Texas County, Oklahoma

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler,David M.; Miller, William A.; Wilson, Travis C.

    2002-03-11

    The Eva South Morrow Sand Unit is located in western Texas County, Oklahoma. The field produces from an upper Morrow sandstone, termed the Eva sandstone, deposited in a transgressive valley-fill sequence. The field is defined as a combination structural stratigraphic trap; the reservoir lies in a convex up -dip bend in the valley and is truncated on the west side by the Teepee Creek fault. Although the field has been a successful waterflood since 1993, reservoir heterogeneity and compartmentalization has impeded overall sweep efficiency. A 4.25 square mile high-resolution, three component three-dimensional (3C3D) seismic survey was acquired in order to improve reservoir characterization and pinpoint the optimal location of a new horizontal producing well, the ESU 13-H.

  2. The future of the reservoirs in the Siret River Basin considering the sediment transport of rivers (ROMANIA

    Directory of Open Access Journals (Sweden)

    Petru OLARIU

    2015-02-01

    Full Text Available The Siret River Basin is characterized by an important use of hydro potential, resulted in the number of reservoirs constructed and operational. The cascade power stage of the reservoirs on Bistrita and Siret rivers indicate the anthropic interventions with different purposes (hydro energy, water supply, irrigation etc. in the Siret River Basin. In terms of the capacity in the Siret River Basin there is a dominance of the small capacity reservoirs, which is given by the less than 20 mil m³ volumes. Only two lakes have capacities over 200 mil m³: Izvoru Muntelui on Bistrita River and Siriu on Buzau River. Based on the monitoring of the alluvial flow at the hydrometric stations, from the Siret River Basin, there have been analysed the sediment yield formation and the solid transit dimensions in order to obtain typical values for the geographical areas of this territory. The silting of these reservoirs was monitored by successive topobatimetric measurements performed by the Bureau of Prognosis, Hydrology and Hydrogeology and a compartment within Hidroelectrica S.A. Piatra Neamt Subsidiary. The quantities of the deposited sediments are very impressive. The annual rates range betwee3 000 – 2 000 000 t/year, depending on the size of the hydrographical basin, the capacity of the reservoirs, the liquid flow and many other factors which may influence the upstream transport of sediments. These rates of sedimentation lead to a high degree of silting in the reservoirs. Many of them are silted over 50% of the initial capacity and the others even more. The effects of the silting have an important impact when analysing the effective exploitation of the reservoirs

  3. Hydrology and sediment yield calibration for the Barasona reservoir catchment (Spain) using SWAT

    Science.gov (United States)

    Palazón, Leticia; Navas, Ana

    2013-04-01

    Hydrological and soil erosion models, as Soil and Water Assessment Tool (SWAT), have become very useful tools and increasingly serve as vital components of integrated environmental assessments that provide information outside of direct field experiments and causal observation. The purpose of this study was to improve the calibration of SWAT model to use it in an alpine catchment as a simulator of processes related to water quality and soil erosion. SWAT is spatially semi-distributed, agro-hydrological model that operates on a daily time step (as a minimum) at basin scale. It is designed to predict the impact of management on water, sediment and agricultural chemical yields in ungaged catchments. SWAT provides physically based algorithms as an option to define many of the important components of the hydrologic cycle. The input requirements of the model are used to describe the climate, soil properties, topography, vegetation, and land management practices. SWAT analyzes small or large catchments by discretising into sub-basins, which are then further subdivided into hydrological response units (HRUs) with homogeneous land use, soil type and slope. SWAT model (SWAT2009) coupled with a GIS interface (ArcSWAT), was applied to the Barasona reservoir catchment located in the central Spanish Pyrenees. The 1509 km2 agro-forestry catchment presents a mountain type climate, an altitudinal range close to 3000 meters and a precipitation variation close to 1000 mm/km. The mountainous characteristics of the catchment, in addition to the scarcity of climate data in the region, require specific calibration for some processes. Snowfall and snowmelt are significant processes in the hydrologic regime of the area and were calibrated in a previous work. In this work some of the challenges of the catchment to model with SWAT which affected the hydrology and the sediment yield simulation were performed as improvement of the previous calibration. Two reservoirs, a karst system which

  4. The occurrence of heavy metals and metal-resistant bacteria in water and bottom sediments of the Straszyn reservoir (Poland

    Directory of Open Access Journals (Sweden)

    Kulbat Eliza

    2017-01-01

    Full Text Available The aim of this study is to investigate the distribution of selected heavy metals and metal–resistant bacteria in water and bottom sediments of the surface drinking water reservoir for Gdańsk. The following sequence of metals in regard to metal concentration in sediments can be written down: Zn > Pb > Cu > Cd. The evaluation of metals accumulation was performed using the Müller index, to indicate the bottom sediment's contamination and geochemical classification of sediment quality according to Polish standards. The Müller geochemical index was changing in a wide range: < 1–4.1. Although the maximum value of Müller's geochemical index determined for copper indicates that the sediment is ‘strongly contaminated’, in general the analysed bottom sediments were classified as the I and II category according to Polish geochemical standards. From the microbiological side a significant part of heterotrophic bacteria isolated from the bottom sediment and surface water (raw and treated water showed a resistance to 0.2 mM and 2 mM concentrations of zinc, copper and lead. The highest percentages of metal–resistant bacteria were recorded in the sediments of the reservoir (60%–88%. The share of metal–resistant strains in the raw water was significantly lower (34%–61%. The results indicate also that water treatment processes may contribute to the selection of resistant strains.

  5. Total and methyl mercury concentrations in sediment and water of a constructed wetland in the Athabasca Oil Sands Region

    International Nuclear Information System (INIS)

    Oswald, Claire J.; Carey, Sean K.

    2016-01-01

    In the Athabasca Oil Sands Region in northeastern Alberta, Canada, oil sands operators are testing the feasibility of peatland construction on the post-mining landscape. In 2009, Syncrude Canada Ltd. began construction of the 52 ha Sandhill Fen pilot watershed, including a 15 ha, hydrologically managed fen peatland built on sand-capped soft oil sands tailings. An integral component of fen reclamation is post-construction monitoring of water quality, including salinity, fluvial carbon, and priority pollutant elements. In this study, the effects of fen reclamation and elevated sulfate levels on mercury (Hg) fate and transport in the constructed system were assessed. Total mercury (THg) and methylmercury (MeHg) concentrations in the fen sediment were lower than in two nearby natural fens, which may be due to the higher mineral content of the Sandhill Fen peat mix and/or a loss of Hg through evasion during the peat harvesting, stockpiling and placement processes. Porewater MeHg concentrations in the Sandhill Fen typically did not exceed 1.0 ng L −1 . The low MeHg concentrations may be a result of elevated porewater sulfate concentrations (mean 346 mg L −1 ) and an increase in sulphide concentrations with depth in the peat, which are known to suppress MeHg production. Total Hg and MeHg concentrations increased during a controlled mid-summer flooding event where the water table rose above the ground surface in most of the fen. The Hg dynamics during this event showed that hydrologic fluctuations in this system exacerbate the release of THg and MeHg downstream. In addition, the elevated SO 4 2− concentrations in the peat porewaters may become a problem with respect to downstream MeHg production once the fen is hydrologically connected to a larger wetland network that is currently being constructed. - Highlights: • A constructed fen peatland in the Athabasca Oil Sands Region was studied. • Total and methyl mercury concentrations in fen sediment and waters

  6. [Sediment-water flux and processes of nutrients and gaseous nitrogen release in a China River Reservoir].

    Science.gov (United States)

    Chen, Zhu-hong; Chen, Neng-wang; Wu, Yin-qi; Mo, Qiong-li; Zhou, Xing-peng; Lu, Ting; Tian, Yun

    2014-09-01

    The key processes and fluxes of nutrients (N and P) and gaseous N (N2 and N2O) across the sediment-water interface in a river reservoir (Xipi) of the Jiulong River watershed in southeast China were studied. Intact core sediment incubation of nutrients exchange, in-situ observation and lab incubation of excess dissolved N2 and N2O (products of nitrification, denitrification and Anammox), and determination of physiochemical and microbe parameters were carried out in 2013 for three representative sites along the lacustrine zone of the reservoir. Results showed that ammonium and phosphate were generally released from sediment to overlying water [with averaged fluxes of N (479.8 ± 675.4) mg. (m2. d)-1 and P (4. 56 ± 0.54) mg. (m2 d) -1] , while nitrate and nitrite diffused into the sediment. Flood events in the wet season could introduce a large amount of particulate organic matter that would be trapped by the dam reservoir, resulting in the high release fluxes of ammonium and phosphate observed in the following low-flow season. No clear spatial variation of sediment nutrient release was found in the lacustrine zone of the reservoir. Gaseous N release was dominated by excess dissolved N2 (98% of total), and the N2 flux from sediment was (15.8 ± 12. 5) mg (m2. d) -1. There was a longitudinal and vertical variation of excess dissolved N2, reflecting the combined results of denitrification and Anammox occurring in anoxic sediment and fluvial transport. Nitrification mainly occurred in the lower lacustrine zone, and the enrichment of N2O was likely regulated by the ratio of ammonium to DIN in water.

  7. Influence of Reservoir Water Level Fluctuations on Sediment Methylmercury Concentrations Downstream of the Historical Black Butte Mercury Mine, OR

    Science.gov (United States)

    Mercury (Hg) is a pollutant of global concern due to its ability to accumulate as methylmercury (MeHg) in biota. Mercury is methylated by anaerobic microorganisms such as sulfate reducing bacteria (SRB) in water and sediment. Throughout North America, reservoirs tend to have e...

  8. Distribution and concentration evaluation of trace and rare earth elements in sediment samples of the Billings and Guarapiranga reservoir systems

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Larissa S.; Fávaro, Déborah I.T., E-mail: defavaro@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (LAN-CRPq/IPEN/CNEN-SP), São Paulo(Brazil). Lab. de Análise por Ativação Neutrônica; Ferreira, Francisco J. [Companhia Ambiental do Estado de São Paulo (ELAI/CETESB), Sao Paulo, SP (Brazil). Setor de Química Inorgânica

    2017-07-01

    Concentration and distribution of trace and rare earth elements in bottom sediment samples collected in the Billings System (including Rio Grande and Guarapiranga Reservoirs) were assessed by using Instrumental Neutron Activation (INAA). To evaluate the sources of anthropogenic contamination the enrichment factor (FE) and the geoacumulation index (IGeo) were calculated using NASC and Guarapiranga Park Soil as Reference Values. Results were compared to the concentration guideline values established by CCME (Canadian Council of Ministers of the Environment) environmental agency for As, Cr and Zn, and values in other published studies. Most points exceeded TEL values and, in some points, PEL values for these elements, indicating poor sediment quality in these reservoirs. In general terms, the elements As, Cr, Sb and Zn through EF and IGeo calculations present enrichment at all points analyzed, in both collection campaigns, except for the Rio Grande Reservoir points. The region where the reservoirs are located receive untreated sewage as well as pollution from urban occupation, industrial and mining activities, making it difficult to accurately identify the pollution sources. This study found higher concentrations of the elements analyzed in the Billings Reservoir, indicating a greater contamination level in relation to the other reservoirs. (author)

  9. Distribution and concentration evaluation of trace and rare earth elements in sediment samples of the Billings and Guarapiranga reservoir systems

    International Nuclear Information System (INIS)

    Silva, Larissa S.; Fávaro, Déborah I.T.; Ferreira, Francisco J.

    2017-01-01

    Concentration and distribution of trace and rare earth elements in bottom sediment samples collected in the Billings System (including Rio Grande and Guarapiranga Reservoirs) were assessed by using Instrumental Neutron Activation (INAA). To evaluate the sources of anthropogenic contamination the enrichment factor (FE) and the geoacumulation index (IGeo) were calculated using NASC and Guarapiranga Park Soil as Reference Values. Results were compared to the concentration guideline values established by CCME (Canadian Council of Ministers of the Environment) environmental agency for As, Cr and Zn, and values in other published studies. Most points exceeded TEL values and, in some points, PEL values for these elements, indicating poor sediment quality in these reservoirs. In general terms, the elements As, Cr, Sb and Zn through EF and IGeo calculations present enrichment at all points analyzed, in both collection campaigns, except for the Rio Grande Reservoir points. The region where the reservoirs are located receive untreated sewage as well as pollution from urban occupation, industrial and mining activities, making it difficult to accurately identify the pollution sources. This study found higher concentrations of the elements analyzed in the Billings Reservoir, indicating a greater contamination level in relation to the other reservoirs. (author)

  10. Distribution and bioavailability of cadmium in ornithogenic coral-sand sediments of the Xisha archipelago, South China Sea

    International Nuclear Information System (INIS)

    Liu Xiaodong; Lou Chuangneng; Xu Liqiang; Sun Liguang

    2012-01-01

    Total cadmium (Cd) concentrations in four ornithogenic coral-sand sedimentary profiles displayed a strong positive correlation with guano-derived phosphorus, but had no correlation with plant-originated organic matter in the top sediments. These results indicate that the total Cd distributions were predominantly controlled by guano input. Bioavailable Cd and zinc (Zn) had a greater input rate in the top sediments with respect to total Cd and total Zn, and a positive correlation with total organic carbon (TOC) derived from plant humus. Multi-regression analysis showed that the total Cd and TOC explained over 80% of the variation of bioavailable Cd, suggesting that both guano and plant inputs could significantly influence the distribution of bioavailable Cd, and that plant biocycling processes contribute more to the recent increase of bioavailable Cd. A pollution assessment indicates that the Yongle archipelago is moderately to strongly polluted with guano-derived Cd. - Guano and plant biocycling processes can exert different influences on the distributions of total Cd and bioavailable Cd in coral-sand ornithogenic sediments.

  11. SILTATION IN RESERVOIRS

    African Journals Online (AJOL)

    Keywords: reservoir model, siltation, sediment, catchment, sediment transport. 1. Introduction. Sediment ... rendered water storage structures useless in less than 25 years. ... reservoir, thus reducing the space available for water storage and ...

  12. Heavy metals and polychlorinated biphenyls (PCBs) sedimentation in the Lianhua Mountain Reservoir, Pearl River Delta, China.

    Science.gov (United States)

    Huang, Jingyu; Amuzu-Sefordzi, Basil; Li, Ming

    2015-05-01

    The Pearl River Delta is one of the biggest electronics manufacturing regions in the world. Due to the presence of abandoned industrial sites and the proliferation of large-scale electronics companies in the past four decades, it is therefore imperative to investigate the extent of heavy metals and polychlorinated biphenyls (PCBs) contamination in the region. Spatial and temporal distribution of heavy metals (Cr, Cu, Ni, Pb, and Zn) and PCBs (PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, and PCB180) in the Lianhua Mountain reservoir in the Pearl River Delta, Dongguan City, China were examined based on a sedimentary profile analysis. Higher concentrations of the heavy metals detected were recorded in bottom sediments whereas 70% of the detected PCBs recorded maximum concentrations in top sediments. The geo-accumulation indices (Igeo) indicate that the study area is uncontaminated to moderately contaminated. Also, the integrated pollution indices (IPI) were above 1, except Pb, which shows that the study area is contaminated with heavy metals from anthropogenic sources. The concentrations of individual heavy metals and PCBs over a period of 60 years were also analyzed in order to establish a historical trend of pollution in the study area. This study provides baseline information on the level and historical trend of heavy metals and PCBs pollution in the study area.

  13. Subduction recycling of continental sediments and the origin of geochemically enriched reservoirs in the deep mantle

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, R.P.; Irifune, T.; Shimizu, N.; Nishiyama, N.; Norman, M.D.; Inoue, T. (Ehime U); (WHOI); (UC); (ANU)

    2008-10-08

    Isotopic and trace element geochemical studies of ocean island basalts (OIBs) have for many years been used to infer the presence of long-lived ({approx} 1-2 Ga old) compositional heterogeneities in the deep mantle related to recycling of crustal lithologies and marine and terrigenous sediments via subduction [e.g., Zindler, A., Hart, S.R., 1986. Chemical geodynamics. Annu. Rev. Earth Planet. Sci. 14, 493-571; Weaver, B.L., 1991. The origin of ocean island basalt end-member compositions: trace element and isotopic constraints. Earth Planet. Sci. Lett. 104, 381-397; Chauvel, C., Hofmann, A.W., Vidal, P., 1992. HIMU-EM: the French Polynesian connection. Earth Planet. Sci. Lett. 110, 99-119; Hofmann, A.W., 1997. Mantle geochemistry: the message from oceanic volcanism. Nature 385, 219-229; Willbold, M., Stracke, A., 2006. Trace element composition of mantle end-members: Implications for recycling of oceanic and upper and lower continental crust. Geochem. Geophys. Geosyst. Q04004. 7, doi:10.1029/2005GC001005]. In particular, models for the EM-1 type ('enriched mantle') OIB reservoir have invoked the presence of subducted, continental-derived sediment to explain high {sup 87}Sr/{sup 86}Sr ratios, low {sup 143}Nd/{sup 144}Nd and {sup 206}Pb/{sup 204}Pb ratios, and extreme enrichments in incompatible elements observed in OIB lavas from, for example, the Pitcairn Island group in the South Pacific [Woodhead, J.D., McCulloch, M.T., 1989; Woodhead, J.D., Devey, C.W., 1993. Geochemistry of the Pitcairn seamounts, I: source character and temporal trends. Earth Planet. Sci. Lett. 116, 81-99; Eisele, J., Sharma, M., Galer, S.J.G., Blichert-Toft, J., Devey, C.W., Hofmann, A.W., 2002. The role of sediment recycling in EM-1 inferred from Os, Pb, Hf, Nd, Sr isotope and trace element systematics of the Pitcairn hotspot. Earth Planet. Sci. Lett. 196, 197-212]. More recently, ultrapotassic, mantle-derived lavas (lamproites) from Gaussberg, Antarctica have been interpreted as

  14. Compound-specific radiocarbon analysis of polycyclic aromatic hydrocarbons (PAHs) in sediments from an urban reservoir

    International Nuclear Information System (INIS)

    Kanke, Hirohide; Uchida, Masao; Okuda, Tomoaki; Yoneda, Minoru; Takada, Hideshige; Shibata, Yasuyuki; Morita, Masatoshi

    2004-01-01

    A quantitative apportionment of polycyclic aromatic hydrocarbons (PAHs) derived from fossil fuel combustion ( 14 C-free) and biomass burning (contemporary 14 C) was carried out using a recently developed compound-specific radiocarbon analysis (CSRA) method for a sediment core from an urban reservoir located in the central Tokyo metropolitan area, Japan. The 14 C abundance of PAHs in the sediments was measured by accelerator mass spectrometry (AMS) after extraction and purification by three types of column chromatography, by high performance liquid chromatography (HPLC), and, subsequently, by a preparative capillary gas chromatography (PCGC) system. This method yielded a sufficient quantity of pure compounds and allowed a high degree of confidence in the determination of 14 C. The fraction modern values (f M ) of individual PAHs (phenanthrene, alkylphenanthrenes, fluoranthene, pyrene and benz[a]anthracene) in the sediments ranged from 0.06 to 0.21. These results suggest that sedimentary PAHs (those compounds mentioned above) were derived mostly from fossil fuel combustion. Three sectioned-downcore profiles (∼40 cm) of the 14 C abundance in phenanthrene and alkylphenanthrenes showed a decreasing trend with depth, that was anti-correlated with the trend of ΣPAHs concentration. The f M values of phenanthrene were also larger than those of alkylphenanthrenes in each section of the core. This result indicates that phenanthrene received a greater contribution from biomass burning than alkylphenanthrenes throughout the core. This finding highlights the method used here as an useful approach to elucidate the source and origin of PAHs in the environment

  15. Dating of Barra Bonita (Rio Tiete - Sao Paulo State, Brazil) reservoir sediments with 210 Pb: historical distribution of heavy metals

    International Nuclear Information System (INIS)

    Cazotti, Raul I.; Silverio, Patricia F.; Mozeto, Antonio A.; Nascimento, Marcos R.L. do

    2002-01-01

    This work presents data on 210 Pb dating and heavy metal contamination of sediment cores collected from the Barra Bonita reservoir, one of the hydroelectric reservoir built in the Tiete River, SE Brazil about 40 years ago. Age calculations were done through the CRS (constant rate of supply) and CIC (constant initial concentration) models. It is well known that dating of lake sediment which are ≥ 100 years old poses no problem as atmospheric 210 Pb activity decreases to almost zero with sediment depth. In this work we present considerations and suggestions towards the applicability of these two models for reservoir dating as a study-case and for lakes in general with ages ≤ 100 years. The results show a good agreement between the CRS and CIC models. In addition, it was also evaluated the historical contamination of heavy metals (total and acid-extractable fraction). Cr, Cu, Ni, Pb and Zn showed an increase in concentration from the bottom to the top part of the cores. This would probably reflect an increase in land use of the Barra Bonita reservoir watershed for the last 40 years. (author)

  16. Occurrence of organotin compounds in river sediments under the dynamic water level conditions in the Three Gorges Reservoir Area, China.

    Science.gov (United States)

    Gao, Jun-Min; Zhang, Ke; Chen, You-Peng; Guo, Jin-Song; Wei, Yun-Mei; Jiang, Wen-Chao; Zhou, Bin; Qiu, Hui

    2015-06-01

    The Three Gorges Project is the largest hydro project in the world, and the water level of the Three Gorges Reservoir (TGR) is dynamic and adjustable with the aim of flood control and electrical power generation. It is necessary to investigate the pollutants and their underlying contamination processes under dynamic water levels to determine their environmental behaviors in the Three Gorges Reservoir Area (TGRA). Here, we report the assessment of organotin compounds (OTs) pollution in the river sediments of the TGRA. Surface sediment samples were collected in the TGRA at low and high water levels. Tributyltin (TBT), triphenyltin (TPhT), and their degradation products in sediments were quantified by gas chromatography-mass spectrometry. Butyltins (BTs) and phenyltins (PhTs) were detected in sediments, and BTs predominated over PhTs in the whole study area under dynamic water level conditions. The concentrations of OTs in sediments varied markedly among locations, and significant concentrations were found in river areas with high levels of boat traffic and wastewater discharge. Sediments at all stations except Cuntan were lightly contaminated with TBT, and total organic carbon (TOC) was a significant factor affecting the fate of TBT in the TGRA. The butyltin and phenyltin degradation indices showed no recent inputs of TBT or TPhT into this region, with the exception of fresh TPhT input at Xiakou Town. Shipping activity, wastewater discharge, and agriculture are the most likely sources of OTs in the TGRA.

  17. Comparisons of Unconsolidated Sediments Analyzed by APXS (MSL-Curiosity) within Gale Crater, Mars: Soils, Sands of the Barchan and Linear Dunes of the Active Bagnold Dune Field, and Ripple-field Sands.

    Science.gov (United States)

    Thompson, L. M.; O'Connell-Cooper, C.; Spray, J. G.; Gellert, R.; Boyd, N. I.; Desouza, E.

    2017-12-01

    The MSL-APXS has analyzed a variety of unconsolidated sediments within the Gale impact crater, including soils, sands from barchan [High, Namib dunes], and linear dunes [Nathan Bridges, Mount Desert dunes], within the active Bagnold dune field, and sands from two smaller ripple fields ("mega-ripples"). The Gale "soils" (unsorted, unconsolidated sediments, ranging from fine-grained particles (including dust) to coarser "pebbly" material [>2 mm]), are, to a large degree, similar to Martian basaltic soils quantified by APXS, at Gusev crater (MER-A_Spirit) and Meridiani Planum (MER-B_Opportunity). Some local contributions are indicated by, for example, the enriched K levels (relative to a martian average basaltic soil [ABS]) within coarser Gale soil samples, and a Cr, Mn, Fe enrichment within finer-grained samples. Sands (grain size 62 µm to 2 mm) of the Bagnold dunes, generally, exhibit elevated Mg and Ni, indicating enrichment from olivine and pyroxene, but depleted S, Cl and Zn, indicating high activity levels and low dust. Compositional differences, related both to position within a dune (i.e., crest versus off-crest sand), and type of dune (linear versus barchan), are identified. Off-crest sands have Na, Al, Si, K, P contents similar to (or slightly depleted, relative to) the ABS, enrichment in Mg, and low dust content, whilst crest sands contain very high Mg and Ni (relative to the ABS), low felsic elemental concentrations and very low dust content. Cr is significantly enriched (and, to a lesser degree, Mn, Fe, Ti) in the off-crest sands of the linear dunes. In contrast, barchan dunes off-crest sands have Cr, Mn, Fe, and Ti abundances similar to those in the Gale soils. Additionally, Ni concentrations in barchan dunes off-crest sands are enriched relative to the linear dunes. Analyses from a small, isolated "mega-ripple" reveal a composition similar to that of the Gale soils, including a high dust content. The second mega-ripple, within a larger ripple field, is

  18. Oxidative stress induced on Cyprinus carpio by contaminants present in the water and sediment of Madin Reservoir.

    Science.gov (United States)

    Galar-Martinez, Marcela; Gomez-Olivan, Leobardo Manuel; Amaya-Chavez, Araceli; Razo-Estrada, Celene; Garcia-Medina, Sandra

    2010-01-01

    Madin Reservoir (MR), located in the State of Mexico, is fed mainly by the Rio Tlalnepantla. MR supplies potable water to the municipalities of Naucalpan and Atizapan, and various recreational activities take place in its vicinity, such as sailing and the fishing of diverse species including the common carp Cyprinus carpio. The purpose of this study was to determine the toxic effects of contaminants present in MR water and sediment on C. carpio. Five sampling stations were selected (those considered to have the most problems due to discharges). Water and sediment samples were taken and toxicity studies were performed, including acute toxicity (lethality) and subacute toxicity assays. The biomarkers used in the subacute assays were lipid peroxidation (LPX) and activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in the liver and brain of test organisms. These biomarkers were also evaluated in local carp, i.e. carp with chronic exposure in situ to reservoir contaminants. Results show that contaminants in the water and sediment of the different sampling stations induce oxidative stress, this toxicity being more evident in samples from stations near the entry point of the Rio Tlalnepantla tributary and in local carp. This may be due to high contaminant levels as well as the fact that the physicochemical characteristics of the matrices might favor their bioavailability. Thus, both the water and sediment of this reservoir are contaminated with xenobiotics hazardous to C. carpio, a species consumed by the local human population.

  19. Potential accumulation of contaminated sediments in a reservoir of a high-Andean watershed: Morphodynamic connections with geochemical processes

    Science.gov (United States)

    Contreras, María. Teresa; Müllendorff, Daniel; Pastén, Pablo; Pizarro, Gonzalo E.; Paola, Chris; Escauriaza, Cristián.

    2015-05-01

    Rapid changes due to anthropic interventions in high-altitude environments, such as the Altiplano region in South America, require new approaches to understand the connections between physical and geochemical processes. Alterations of the water quality linked to the river morphology can affect the ecosystems and human development in the long term. The future construction of a reservoir in the Lluta River, located in northern Chile, will change the spatial distribution of arsenic-rich sediments, which can have significant effects on the lower parts of the watershed. In this investigation, we develop a coupled numerical model to predict and evaluate the interactions between morphodynamic changes in the Lluta reservoir, and conditions that can potentially desorb arsenic from the sediments. Assuming that contaminants are mobilized under anaerobic conditions, we calculate the oxygen concentration within the sediments to study the interactions of the delta progradation with the potential arsenic release. This work provides a framework for future studies aimed to analyze the complex connections between morphodynamics and water quality, when contaminant-rich sediments accumulate in a reservoir. The tool can also help to design effective risk management and remediation strategies in these extreme environments. This article was corrected on 15 JUNE 2015. See the end of the full text for details.

  20. Deep River Velocity and Sediment Profiles and the Suspended Sand Load,

    Science.gov (United States)

    1963-02-01

    5.03 x IO~~ ATCHAFALAVA RIVER WIDTH : 1587 FT D 5, : 6.75 w 0 ~ FT SIMM ESPORT u : 6.66 FPS WATER TEMP. : 70 F d : 46.3 FT FINE SAND PORTION OP BED...1.34 * 10 3FT SIMM ESPORT ~ : 5.85 FPS WATCR TEMP. :69 ’F d : 47.7 FT FiNE SAND PORTION OP BED MATERIAL : 39.$ ~~ FIG. 16...DEC. 14,196 1 Q : 218,000 CF’S S : 336 *io ’~ ATCHAFALAVA RIVERWIDTH ?~ FPS WATER TEMP : løOx I0~~ FT SIMM ESPORT d : 4 1 .7 FT FINE SAND PORTION OF B

  1. Effects of Aging Quartz Sand and Hanford Site Sediment with Sodium Hydroxide on Radionuclide Sorption Coefficients and Sediment Physical and Hydrologic Properties: Final Report for Subtask 2a

    Energy Technology Data Exchange (ETDEWEB)

    DI Kaplan; JC Ritter; KE Parker

    1998-12-04

    Column and batch experiments were conducted in fiscal year 1998 at Pacific Northwest National Laboratory to evaluate the effect of varying concentrations of NaOH on the sorptive, physical, and hydraulic properties of two media, a quartz sand and a composite subsurface sediment from the 200-East Area of the Hanford Site. The NaOH solutions were used as a simplified effluent from a low-activity glass waste form. These experiments were conducted over a limited (O-to 10-month) contact time, with respect to the 10,000-to 100,000-year scenarios described in the Immobilized Low-Activity Waste- Performance Assessment (ILAW-PA). Wheq these two solids were put in contact with the NaOH solutions, dissolution was evident by a substantial increase in dissolved Si concentrations in the leachates. Incremental increases in NaOH con- centrations, resulted in corresponding increases in Si concentrations. A number of physical and hydraulic properties also changed as the NaOH concentrations were changed. It was observed that quartz sand was less reactive than the composite sediment. Further, moisture- retention measurements were made on the quartz sand and composite sedimen$ which showed that the NaOH-treated solids retained more water than the non-NaOH-treated solids. Because the other chemical, physical, and hydraulic measurements did not change dramatically after the high-NaOH treatments, the greater moisture retention of the high-NaOH treatments was attributed to a "salt effect" and not to the formation of small particles during the dissolution (weathering). The distribution coefficients (IQ) for Cs and Sr were measured on the NaOH-treated sediments, with decreases from -3,000 to 1,000 and 1,300 to 300 mL/g noted, respectively, at the 0.01-to 1.O-M NaOH levels. There was no apparent trend for the Sr & values with contact time. The lack of such a trend sug- gests that dissolution of sediment particles is not controlling the drop in IQ rather, it is the competition of the added Na

  2. Total and methyl mercury concentrations in sediment and water of a constructed wetland in the Athabasca Oil Sands Region.

    Science.gov (United States)

    Oswald, Claire J; Carey, Sean K

    2016-06-01

    In the Athabasca Oil Sands Region in northeastern Alberta, Canada, oil sands operators are testing the feasibility of peatland construction on the post-mining landscape. In 2009, Syncrude Canada Ltd. began construction of the 52 ha Sandhill Fen pilot watershed, including a 15 ha, hydrologically managed fen peatland built on sand-capped soft oil sands tailings. An integral component of fen reclamation is post-construction monitoring of water quality, including salinity, fluvial carbon, and priority pollutant elements. In this study, the effects of fen reclamation and elevated sulfate levels on mercury (Hg) fate and transport in the constructed system were assessed. Total mercury (THg) and methylmercury (MeHg) concentrations in the fen sediment were lower than in two nearby natural fens, which may be due to the higher mineral content of the Sandhill Fen peat mix and/or a loss of Hg through evasion during the peat harvesting, stockpiling and placement processes. Porewater MeHg concentrations in the Sandhill Fen typically did not exceed 1.0 ng L(-1). The low MeHg concentrations may be a result of elevated porewater sulfate concentrations (mean 346 mg L(-1)) and an increase in sulphide concentrations with depth in the peat, which are known to suppress MeHg production. Total Hg and MeHg concentrations increased during a controlled mid-summer flooding event where the water table rose above the ground surface in most of the fen. The Hg dynamics during this event showed that hydrologic fluctuations in this system exacerbate the release of THg and MeHg downstream. In addition, the elevated SO4(2-) concentrations in the peat porewaters may become a problem with respect to downstream MeHg production once the fen is hydrologically connected to a larger wetland network that is currently being constructed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Investigation of echo sounding parameters for the characterisation of bottom sediments in a sub-tropical reservoir

    Directory of Open Access Journals (Sweden)

    Stephan Hilgert

    2016-07-01

    Full Text Available The increasing number of reservoirs around the world today reaches a surface area of around 500,000 km², equaling one third of that of non-artificial surface water bodies. By impounding rivers through the construction of dams, riverine systems and biochemical cycles are disrupted. Different types of transported materials are trapped behind the dams and form layers of sediment. A method to characterise the spatially extensive sediment volumes with an EA 400 echo sounder was tested in the Vossoroca reservoir in the southeast of Brazil, Paraná State. A number of core and grab samples was taken and analysed for a variety of chemical and physical parameters. These data served as ground truthing for the hydro-acoustic assessment of the sediment. Eight hydro-acoustic parameters were derived from the echo signals using the Sonar5-Pro software. The major objective of defining the optimal survey parameters for the echo sounder as well as determining the difference between core and grab samples was reached by correlating the various single parameters and identifying the best combinations. Density and grain size distribution represented the best detectable sediment features with r-values of 0.94 and 0.95. The lower 38 kHz frequency generally had a better performance than the 200 kHz frequency. Results show that core samples reached a significantly higher quality of correlation for sediment characterisation. Additionally, it is was found that shorter pulse lengths yield a better characterisation. The results underline the potential of single beam echo sounders for extensive sediment characterisation. This methodology may be used for future mass balance estimations of large reservoirs.

  4. Enrichment and geochemical mobility of heavy metals in bottom sediment of the Hoedong reservoir, Korea and their source apportionment.

    Science.gov (United States)

    Lee, Pyeong-Koo; Kang, Min-Ju; Yu, Soonyoung; Ko, Kyung-Seok; Ha, Kyoochul; Shin, Seong-Cheon; Park, Jung Han

    2017-10-01

    Physicochemical characteristics of bottom sediment in the Hoedong reservoir were studied to evaluate the effectiveness of the reservoir as traps for trace metals. Roadside soil, stream sediment and background soil were also studied for comparison. Sequential extractions were carried out, and lead isotopic compositions of each extraction were determined to apportion Pb sources. Besides, particle size distribution of roadside soil, and metal concentrations and Pb isotopes of each size group were determined to characterize metal contamination. In result, Zn and Cu were enriched in sediment through roadside soil. The data on metal partitioning implied that Zn posed potential hazards for water quality. Meanwhile, the noticeable reduction of the 206 Pb/ 207 Pb isotopic ratio in the acid-soluble fraction in the size group 200 μm - 2 mm of national roadside soil indicated that this size group was highly contaminated by automotive emission with precipitation of acid-soluble secondary minerals during evaporation. Based on the Pb isotopic ratios, the dry deposition of Asian dust (AD) and non-Asian dust (NAD) affected roadside soil, while the effects of AD and NAD on bottom sediment appeared to be low given the low metal concentrations in sediment. Metal concentrations and Pb isotopic compositions indicated that sediments were a mixture of background and roadside soil. Source apportionment calculations showed that the average proportion of traffic Pb in bottom and stream sediments was respectively 34 and 31% in non-residual fractions, and 26 and 28% in residual fraction. The residual fraction of sediments appeared to be as contaminated as the non-residual fractions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Atmospheric pollution history at Linfen (China) uncovered by magnetic and chemical parameters of sediments from a water reservoir

    International Nuclear Information System (INIS)

    Ma, Mingming; Hu, Shouyun; Cao, Liwan; Appel, Erwin; Wang, Longsheng

    2015-01-01

    We studied magnetic and chemical parameters of sediments from sediments of a water reservoir at Linfen (China) in order to quantitatively reconstruct the atmospheric pollution history in this region. The results show that the main magnetic phases are magnetite and maghemite originating from the surrounding catchment and from anthropogenic activities, and there is a significant positive relationship between magnetic concentration parameters and heavy metals concentrations, indicating that magnetic proxies can be used to monitor the anthropogenic pollution. In order to uncover the atmospheric pollution history, we combined the known events of environmental improvement with variations of magnetic susceptibility (χ) and heavy metals along the cores to obtain a detailed chronological framework. In addition, air comprehensive pollution index (ACPI) was reconstructed from regression equation among magnetic and chemical parameters as well as atmospheric monitoring data. Based on these results, the atmospheric pollution history was successfully reconstructed. - Highlights: • Magnetic proxies can be used to monitor the heavy mental pollution in sediments. • Accurate age model was obtained using known events of environmental improvement. • Regression equation was obtained among sediment records and monitoring data. • Atmospheric pollution history was quantitatively reconstructed. - Atmospheric pollution history was quantitatively reconstructed using magnetic and chemical records of reservoir sediments combined with atmospheric monitoring data

  6. Scaling of Sediment Dynamics in a Reach-Scale Laboratory Model of a Sand-Bed Stream with Riparian Vegetation

    Science.gov (United States)

    Gorrick, S.; Rodriguez, J. F.

    2011-12-01

    A movable bed physical model was designed in a laboratory flume to simulate both bed and suspended load transport in a mildly sinuous sand-bed stream. Model simulations investigated the impact of different vegetation arrangements along the outer bank to evaluate rehabilitation options. Preserving similitude in the 1:16 laboratory model was very important. In this presentation the scaling approach, as well as the successes and challenges of the strategy are outlined. Firstly a near-bankfull flow event was chosen for laboratory simulation. In nature, bankfull events at the field site deposit new in-channel features but cause only small amounts of bank erosion. Thus the fixed banks in the model were not a drastic simplification. Next, and as in other studies, the flow velocity and turbulence measurements were collected in separate fixed bed experiments. The scaling of flow in these experiments was simply maintained by matching the Froude number and roughness levels. The subsequent movable bed experiments were then conducted under similar hydrodynamic conditions. In nature, the sand-bed stream is fairly typical; in high flows most sediment transport occurs in suspension and migrating dunes cover the bed. To achieve similar dynamics in the model equivalent values of the dimensionless bed shear stress and the particle Reynolds number were important. Close values of the two dimensionless numbers were achieved with lightweight sediments (R=0.3) including coal and apricot pips with a particle size distribution similar to that of the field site. Overall the moveable bed experiments were able to replicate the dominant sediment dynamics present in the stream during a bankfull flow and yielded relevant information for the analysis of the effects of riparian vegetation. There was a potential conflict in the strategy, in that grain roughness was exaggerated with respect to nature. The advantage of this strategy is that although grain roughness is exaggerated, the similarity of

  7. Sedimentology and preservation of aeolian sediments on steep terrains: Incipient sand ramps on the Atacama coast (northern Chile)

    Science.gov (United States)

    Ventra, Dario; Rodríguez-López, Juan Pedro; de Boer, Poppe L.

    2017-05-01

    The origin of topographically controlled aeolian landforms in high-relief settings is difficult to synthesize under general models, given the dependence of such accumulations on local morphology. Quaternary sand ramps have been linked to palaeoclimate, regional geomorphology and wind patterns; however, controls on the early development and preservation of such landforms are poorly known. This study describes the morphology and sedimentology of complex sedimentary aprons along steep coastal slopes in the Atacama Desert (Chile). Direct slope accessibility and continuous stratigraphic exposures enable comparisons between active processes and stratigraphic signatures. Stratigraphic facies distribution and its links with patterns of aeolian deposition show that the preservation of wind-laid sediments depends on the morphology and processes of specific slope sectors. The spatial organization of runoff depends on bedrock configuration and directly controls the permanence or erosion of aeolian sediment. The occurrence of either water or mass flows depends on the role of aeolian fines in the rheology of flash floods. In turn, the establishment of a rugged surface topography controlled by patterns of mass-flow deposition creates local accommodation for aeolian fines, sustaining the initial aggradation of a colluvial-aeolian system. By contrast, slopes subject to runoff develop a thin, extensive aeolian mantle whose featureless surface is subject mostly to sediment bypass down- and across-slope; the corresponding stratigraphic record comprises almost exclusively thin debris-flow and sheetflood deposits. Slope morphology and processes are fundamental in promoting or inhibiting aeolian aggradation in mountain settings. Long-term sand-ramp construction depends on climate and regional topography, but the initial development is probably controlled by local geomorphic factors. The observed interactions between wind and topography in the study area may also represent a process

  8. Assessment of existing sediment transport models for sand barrier dynamics under wave and currents

    Digital Repository Service at National Institute of Oceanography (India)

    Thuy, T.T.V.; Nghiem, L.T.; Jayakumar, S.; Nielsen, P.

    The paper summarizes morphology changes over rippled sand barriers under wave and wave combined current of 27 laboratorial experiments. Data of 4 wave conditions (H=10cm, T=1s; H=12cm, T=1s; H=12cm, T=1.5s; H=14cm, T=1.5s) and 6 currents (Q= 10, -10...

  9. Reservoir age variations and stable isotope values of bulk sediment in a core from the Limfjord, Denmark

    DEFF Research Database (Denmark)

    Philippsen, Bente; Olsen, Jesper; Rasmussen, Peter

    The Limfjord is a sound in Northern Jutland, Denmark, connecting the North Sea with the Kattegat. A multi-proxy approach has been applied to a sediment core from Kilen, a former fjord arm near the town of Struer, to reveal the Limfjord’s development in more detail. In this paper, we concentrate...... on radiocarbon dating of shells and on stable isotope measurements of bulk sediment from 7400 to 1300 cal BP. Reservoir ages in coastal waters and estuaries can differ considerably from the global model ocean. The seas around Denmark have a reservoir age of c. 400 years, while a hardwater effect of a few...... of organic matter can thus be estimated. The d13C and C/N inferred salinity can be related to changes in Delta-R and other palaeoenvironmental proxies. An increasing marine influence throughout the largest part of the core is followed by large variations around 2000 cal BP....

  10. A mathematical model of reservoir sediment quality prediction based on land-use and erosion processes in watershed

    Science.gov (United States)

    Junakova, N.; Balintova, M.; Junak, J.

    2017-10-01

    The aim of this paper is to propose a mathematical model for determining of total nitrogen (N) and phosphorus (P) content in eroded soil particles with emphasis on prediction of bottom sediment quality in reservoirs. The adsorbed nutrient concentrations are calculated using the Universal Soil Loss Equation (USLE) extended by the determination of the average soil nutrient concentration in top soils. The average annual vegetation and management factor is divided into five periods of the cropping cycle. For selected plants, the average plant nutrient uptake divided into five cropping periods is also proposed. The average nutrient concentrations in eroded soil particles in adsorbed form are modified by sediment enrichment ratio to obtain the total nutrient content in transported soil particles. The model was designed for the conditions of north-eastern Slovakia. The study was carried out in the agricultural basin of the small water reservoir Klusov.

  11. Water-quality trends in the Rio Grande/Rio Bravo Basin using sediment cores from reservoirs

    Science.gov (United States)

    Van Metre, Peter C.; Mahler, B.J.; Callender, Edward C.

    1997-01-01

    Water-quality trends reflect the relation between water quality and human activities, chronicling changes in concentrations of environmental contaminants, introduction of new contaminants, and successful efforts in environmental pollution remediation. Historical data available for analyzing trends often have severe limitations, from questionable accuracy to unknown sampling and analytic methodologies. Where data are unavailable or have such limitations, water-quality trends sometimes can be reconstructed using sediment cores from lakes and reservoirs.

  12. Laboratory tests of bentonite stabilization of bottom sediments from a dam reservoir in relation to their usage in municipal solid waste landfill liners

    Directory of Open Access Journals (Sweden)

    Karolina Koś

    2016-09-01

    Full Text Available Geotechnical parameters of bottom sediments from a dam reservoir (Rzeszowski Reservoir, Poland with bentonite addition are presented in the paper. Tests were carried out in the aspect of the possible usage of sediments as a material for soil liners in Municipal Solid Waste Landfill. Mentioned sediments did not fulfilled the permeability and plasticity criteria defined for soils that can be used in liners. The bentonite addition caused, among other things, a decrease in permeability coefficient and increase in plasticity index. Based on the carried out tests it was stated that sediments with 6% addition of bentonite fulfil all requirements and can be used for liners in MSWL.

  13. Radiocarbon reservoir effect from shell and plant pairs in Holocene sediments around the Yeongsan River in Korea

    International Nuclear Information System (INIS)

    Nakanishi, Toshimichi; Hong, Wan; Sung, Ki Suk; Lim, Jaesoo

    2013-01-01

    The marine reservoir effect was measured by comparing the radiocarbon ages of shell and plant pairs obtained from the same horizons of a sediment core around the Yeongsan River in the southwestern part of the Korean Peninsula. The Holocene sediment formed in five environments: tidal flat, inner bay, shallow marine, flood plain, and embankment from bottom to top. The tidal flat and shallow marine sediments should be good indicators of marine reservoir effect, as they formed in coastal environments where it was easy to access not only marine shells but also terrestrial plants. Some old detritus could be identified and removed, based on reliable accumulation curves and sedimentological interpretation. Hence, the age differences between the plants and shells could be successfully evaluated, and they indicated that the marine reservoir effect varied over time between 0 and 500 years. There was an increase of this effect at ca. 8000 cal year BP and a decrease at ca. 5000 cal year BP, possibly linked with coastal environment changes induced by sea level changes and by changes in the circulation of seawater.

  14. Radiocarbon reservoir effect from shell and plant pairs in Holocene sediments around the Yeongsan River in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Toshimichi [Korea Institute of Geoscience and Mineral Resources, Gwahang-no 124, Yuseong-gu, Daejeon (Korea, Republic of); Hong, Wan, E-mail: whong@kigam.re.kr [Korea Institute of Geoscience and Mineral Resources, Gwahang-no 124, Yuseong-gu, Daejeon (Korea, Republic of); Sung, Ki Suk; Lim, Jaesoo [Korea Institute of Geoscience and Mineral Resources, Gwahang-no 124, Yuseong-gu, Daejeon (Korea, Republic of)

    2013-01-15

    The marine reservoir effect was measured by comparing the radiocarbon ages of shell and plant pairs obtained from the same horizons of a sediment core around the Yeongsan River in the southwestern part of the Korean Peninsula. The Holocene sediment formed in five environments: tidal flat, inner bay, shallow marine, flood plain, and embankment from bottom to top. The tidal flat and shallow marine sediments should be good indicators of marine reservoir effect, as they formed in coastal environments where it was easy to access not only marine shells but also terrestrial plants. Some old detritus could be identified and removed, based on reliable accumulation curves and sedimentological interpretation. Hence, the age differences between the plants and shells could be successfully evaluated, and they indicated that the marine reservoir effect varied over time between 0 and 500 years. There was an increase of this effect at ca. 8000 cal year BP and a decrease at ca. 5000 cal year BP, possibly linked with coastal environment changes induced by sea level changes and by changes in the circulation of seawater.

  15. Observations on sediment sources in the Lower Athabasca River basin: implications of natural hydrocarbons inputs from oil sands deposits

    International Nuclear Information System (INIS)

    Conly, F.M.

    1999-01-01

    Government, industry and public concern exists over the environmental consequences of the development of the oil sand deposits in the McMurray Formation in the lower Athabasca River basin, Alberta. The impact of this development is unclear and is undergoing investigation. Investigations to date have focussed on the nature of the effluent produced by the extraction industry and its effect on biotic systems, and on the spatial distribution of hydrocarbon contaminants associated with deposited fluvial sediments. Natural hydrocarbon outcrops may be responsible for observed biomarker responses in areas not exposed to industrial effluent. Given this source of hydrocarbons and doubt concerning its environmental impact, it is difficult to ascertain the impact of oil extraction activities within a fluvial system. A study was conducted to determine the nature and extent of natural hydrocarbon releases within the context of the sediment regime of the lower Athabasca River basin. A description is included of observations from the field and a context is set up for assessing sediment-bound hydrocarbon contaminants in the lower Athabasca River basin. Abstract only included

  16. Analyzing the contribution of climate change to long-term variations in sediment nitrogen sources for reservoirs/lakes

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Xinghui, E-mail: xiaxh@bnu.edu.cn [School of Environment, Beijing Normal University, State Key Laboratory of Water Environment Simulation/Key Laboratory of Water and Sediment Sciences of Ministry of Education, Beijing 100875 (China); Wu, Qiong; Zhu, Baotong; Zhao, Pujun [School of Environment, Beijing Normal University, State Key Laboratory of Water Environment Simulation/Key Laboratory of Water and Sediment Sciences of Ministry of Education, Beijing 100875 (China); Zhang, Shangwei [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstraße 15, Leipzig 04318 (Germany); Yang, Lingyan [Beijing Municipal Environmental Monitoring Center, Beijing 100048 (China)

    2015-08-01

    We applied a mixing model based on stable isotopic δ{sup 13}C, δ{sup 15}N, and C:N ratios to estimate the contributions of multiple sources to sediment nitrogen. We also developed a conceptual model describing and analyzing the impacts of climate change on nitrogen enrichment. These two models were conducted in Miyun Reservoir to analyze the contribution of climate change to the variations in sediment nitrogen sources based on two {sup 210}Pb and {sup 137}Cs dated sediment cores. The results showed that during the past 50 years, average contributions of soil and fertilizer, submerged macrophytes, N{sub 2}-fixing phytoplankton, and non-N{sub 2}-fixing phytoplankton were 40.7%, 40.3%, 11.8%, and 7.2%, respectively. In addition, total nitrogen (TN) contents in sediment showed significant increasing trends from 1960 to 2010, and sediment nitrogen of both submerged macrophytes and phytoplankton sources exhibited significant increasing trends during the past 50 years. In contrast, soil and fertilizer sources showed a significant decreasing trend from 1990 to 2010. According to the changing trend of N{sub 2}-fixing phytoplankton, changes of temperature and sunshine duration accounted for at least 43% of the trend in the sediment nitrogen enrichment over the past 50 years. Regression analysis of the climatic factors on nitrogen sources showed that the contributions of precipitation, temperature, and sunshine duration to the variations in sediment nitrogen sources ranged from 18.5% to 60.3%. The study demonstrates that the mixing model provides a robust method for calculating the contribution of multiple nitrogen sources in sediment, and this study also suggests that N{sub 2}-fixing phytoplankton could be regarded as an important response factor for assessing the impacts of climate change on nitrogen enrichment. - Highlights: • A mixing model was built to analyze sediment N sources of lakes/reservoirs. • Fertilizer/soil and macrophytes showed decreasing trends during

  17. Analyzing the contribution of climate change to long-term variations in sediment nitrogen sources for reservoirs/lakes

    International Nuclear Information System (INIS)

    Xia, Xinghui; Wu, Qiong; Zhu, Baotong; Zhao, Pujun; Zhang, Shangwei; Yang, Lingyan

    2015-01-01

    We applied a mixing model based on stable isotopic δ 13 C, δ 15 N, and C:N ratios to estimate the contributions of multiple sources to sediment nitrogen. We also developed a conceptual model describing and analyzing the impacts of climate change on nitrogen enrichment. These two models were conducted in Miyun Reservoir to analyze the contribution of climate change to the variations in sediment nitrogen sources based on two 210 Pb and 137 Cs dated sediment cores. The results showed that during the past 50 years, average contributions of soil and fertilizer, submerged macrophytes, N 2 -fixing phytoplankton, and non-N 2 -fixing phytoplankton were 40.7%, 40.3%, 11.8%, and 7.2%, respectively. In addition, total nitrogen (TN) contents in sediment showed significant increasing trends from 1960 to 2010, and sediment nitrogen of both submerged macrophytes and phytoplankton sources exhibited significant increasing trends during the past 50 years. In contrast, soil and fertilizer sources showed a significant decreasing trend from 1990 to 2010. According to the changing trend of N 2 -fixing phytoplankton, changes of temperature and sunshine duration accounted for at least 43% of the trend in the sediment nitrogen enrichment over the past 50 years. Regression analysis of the climatic factors on nitrogen sources showed that the contributions of precipitation, temperature, and sunshine duration to the variations in sediment nitrogen sources ranged from 18.5% to 60.3%. The study demonstrates that the mixing model provides a robust method for calculating the contribution of multiple nitrogen sources in sediment, and this study also suggests that N 2 -fixing phytoplankton could be regarded as an important response factor for assessing the impacts of climate change on nitrogen enrichment. - Highlights: • A mixing model was built to analyze sediment N sources of lakes/reservoirs. • Fertilizer/soil and macrophytes showed decreasing trends during the past two decades.

  18. Sediment yield estimation in mountain catchments of the Camastra reservoir, southern Italy: a comparison among different empirical methods

    Science.gov (United States)

    Lazzari, Maurizio; Danese, Maria; Gioia, Dario; Piccarreta, Marco

    2013-04-01

    Sedimentary budget estimation is an important topic for both scientific and social community, because it is crucial to understand both dynamics of orogenic belts and many practical problems, such as soil conservation and sediment accumulation in reservoir. Estimations of sediment yield or denudation rates in southern-central Italy are generally obtained by simple empirical relationships based on statistical regression between geomorphic parameters of the drainage network and the measured suspended sediment yield at the outlet of several drainage basins or through the use of models based on sediment delivery ratio or on soil loss equations. In this work, we perform a study of catchment dynamics and an estimation of sedimentary yield for several mountain catchments of the central-western sector of the Basilicata region, southern Italy. Sediment yield estimation has been obtained through both an indirect estimation of suspended sediment yield based on the Tu index (mean annual suspension sediment yield, Ciccacci et al., 1980) and the application of the Rusle (Renard et al., 1997) and the USPED (Mitasova et al., 1996) empirical methods. The preliminary results indicate a reliable difference between the RUSLE and USPED methods and the estimation based on the Tu index; a critical data analysis of results has been carried out considering also the present-day spatial distribution of erosion, transport and depositional processes in relation to the maps obtained from the application of those different empirical methods. The studied catchments drain an artificial reservoir (i.e. the Camastra dam), where a detailed evaluation of the amount of historical sediment storage has been collected. Sediment yield estimation obtained by means of the empirical methods have been compared and checked with historical data of sediment accumulation measured in the artificial reservoir of the Camastra dam. The validation of such estimations of sediment yield at the scale of large catchments

  19. Turbulent flow structures and aeolian sediment transport over a barchan sand dune

    Science.gov (United States)

    Wiggs, G. F. S.; Weaver, C. M.

    2012-03-01

    The turbulent structure of airflow over a barchan sand dune is determined using quadrant analysis of wind velocity data derived from sonic anemometers. Results indicate an increased frequency of ejection and sweep events in the toe region of the dune, characteristic of the turbulent bursting process. In contrast, at the crest there was a significant increase in the occurrence of outward interactions. Combined with high frequency saltation data our analyses show that turbulent structures characterised by a positive streamwise fluctuating velocity (+u‧ sweeps at the toe and outward interactions at the crest) have a dominant influence on sand transport on the dune, together accounting for up to 83% and 95% of transporting events at the toe and crest respectively.

  20. Biogeochemical controls on the speciation and aquatic toxicity of vanadium and other metals in sediments from a river reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Nedrich, Sara M.; Chappaz, Anthony; Hudson, Michelle L.; Brown, Steven S.; Burton, G. Allen

    2018-01-01

    Effects of hydrologic variability on reservoir biogeochemistry are relatively unknown, particularly for less studied metals like vanadium (V). Further, few studies have investigated the fate and effects of sediment-associated V to aquatic organisms in hydrologically variable systems. Our primary objective was to assess effects of hydrologic manipulation on speciation and toxicity of V (range: 635 to 1620 mg kg- 1) and other metals to Hyalella azteca and Daphnia magna. Sediments were collected from a reservoir located in a former mining area and microcosm experiments were conducted to emulate 7-day drying and inundation periods. Despite high sediment concentrations, V bioavailability remained low with no significant effects to organism survival, growth, or reproduction. The lack of V toxicity was attributed to reduced speciation (III, IV), non-labile complexation, and sorption to Al/Fe/Mn-oxyhydroxides. Zinc (Zn) increased in surface and porewater with inundation, for some sediments exceeding the U.S. EPA threshold for chronic toxicity. While no effects of Zn to organism survival or growth were observed, Zn body concentrations were negatively correlated with H. azteca growth. Results from this study indicate that V bioavailability and environmental risk is dependent on V-speciation, and V is less influenced by hydrologic variability than more labile metals such as Zn.

  1. Stochastic Modeling of Sediment Connectivity for Reconstructing Sand Fluxes and Origins in the Unmonitored Se Kong, Se San, and Sre Pok Tributaries of the Mekong River

    Science.gov (United States)

    Schmitt, R. J. P.; Bizzi, S.; Castelletti, A. F.; Kondolf, G. M.

    2018-01-01

    Sediment supply to rivers, subsequent fluvial transport, and the resulting sediment connectivity on network scales are often sparsely monitored and subject to major uncertainty. We propose to approach that uncertainty by adopting a stochastic method for modeling network sediment connectivity, which we present for the Se Kong, Se San, and Sre Pok (3S) tributaries of the Mekong. We quantify how unknown properties of sand sources translate into uncertainty regarding network connectivity by running the CASCADE (CAtchment Sediment Connectivity And DElivery) modeling framework in a Monte Carlo approach for 7,500 random realizations. Only a small ensemble of realizations reproduces downstream observations of sand transport. This ensemble presents an inverse stochastic approximation of the magnitude and variability of transport capacity, sediment flux, and grain size distribution of the sediment transported in the network (i.e., upscaling point observations to the entire network). The approximated magnitude of sand delivered from each tributary to the Mekong is controlled by reaches of low transport capacity ("bottlenecks"). These bottlenecks limit the ability to predict transport in the upper parts of the catchment through inverse stochastic approximation, a limitation that could be addressed by targeted monitoring upstream of identified bottlenecks. Nonetheless, bottlenecks also allow a clear partitioning of natural sand deliveries from the 3S to the Mekong, with the Se Kong delivering less (1.9 Mt/yr) and coarser (median grain size: 0.4 mm) sand than the Se San (5.3 Mt/yr, 0.22 mm) and Sre Pok (11 Mt/yr, 0.19 mm).

  2. Application of Flumethrin Pour-On on Reservoir Dogs and Its Efficacy against Sand Flies in Endemic Focus of Visceral Leishmaniasis, Meshkinshahr, Iran

    Directory of Open Access Journals (Sweden)

    MohammadReza Jalilnavaz

    2015-10-01

    Full Text Available Background: Visceral leishmaniasis (VL is one of the most important parasitic zoonotic diseases in the world. Do­mestic dogs are the main domestic reservoirs of VL in endemic foci of Iran. Various methods, including vaccination, treatment of dogs, detection and removal of infected dogs have different results around the world. General policy on control of canine visceral leishmaniasis is protection of them from sand fly bites. The aim of this study was evalua­tion of pour-on application of flumethrin on dogs against blood-feeding and mortality of field-caught sand flies.Methods: Once every 20 days from May untill September 2013, the treated and control dogs were exposed with field caught sandflies for 2 hours under bed net traps. After the exposure time, both alive and dead sand flies were trans­ferred in netted cups to the laboratory. The mortality rate of them was assessed after 24 hours. The blood-fed or un­fed conditions were determined 2 hours after exposure to the dogs under stereomicroscope.Results: The blood feeding index was varied from 12.0 to 25.0 % and 53.0 to 58.0 % for treated and control dogs respectively (P< 0.0001. The blood feeding inhibition was 75.0–87.0 % and 41.0–46.0 % for the control and treated dogs (P< 0.0001, respectively.The total mortality rate was 94.0–100 % and 19.0–58.0 % respectively for the treated and control groups (P< 0.001.Conclustion: Application of pour-on flumethrin on dogs caused 90–100 % mortality until 2.5 month and inhibited the blood-feeding of sand flies. 

  3. Effects of lakes and reservoirs on annual river nitrogen, phosphorus, and sediment export in agricultural and forested landscapes

    Science.gov (United States)

    Powers, Stephen M.; Robertson, Dale M.; Stanley, Emily H.

    2014-01-01

    Recently, effects of lakes and reservoirs on river nutrient export have been incorporated into landscape biogeochemical models. Because annual export varies with precipitation, there is a need to examine the biogeochemical role of lakes and reservoirs over time frames that incorporate interannual variability in precipitation. We examined long-term (~20 years) time series of river export (annual mass yield, Y, and flow-weighted mean annual concentration, C) for total nitrogen (TN), total phosphorus (TP), and total suspended sediment (TSS) from 54 catchments in Wisconsin, USA. Catchments were classified as small agricultural, large agricultural, and forested by use of a cluster analysis, and these varied in lentic coverage (percentage of catchment lake or reservoir water that was connected to river network). Mean annual export and interannual variability (CV) of export (for both Y and C) were higher in agricultural catchments relative to forested catchments for TP, TN, and TSS. In both agricultural and forested settings, mean and maximum annual TN yields were lower in the presence of lakes and reservoirs, suggesting lentic denitrification or N burial. There was also evidence of long-term lentic TP and TSS retention, especially when viewed in terms of maximum annual yield, suggesting sedimentation during high loading years. Lentic catchments had lower interannual variability in export. For TP and TSS, interannual variability in mass yield was often >50% higher than interannual variability in water yield, whereas TN variability more closely followed water (discharge) variability. Our results indicate that long-term mass export through rivers depends on interacting terrestrial, aquatic, and meteorological factors in which the presence of lakes and reservoirs can reduce the magnitude of export, stabilize interannual variability in export, as well as introduce export time lags.

  4. 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

  5. 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

  6. How tides and waves enhance aeolian sediment transport at the sand motor mega-nourishment

    NARCIS (Netherlands)

    Hoonhout, B.M.; Luijendijk, A.P.; de Vries, S.; Roelvink, D.; Aagaard, T.; Deigaard, R.; Fuhrman, D.

    2017-01-01

    Expanding knowledge concerning the close entanglement between subtidal and subaerial processes in coastal environments initiated the development of the open-source Windsurf modeling framework that enables us to simulate
    multi-fraction sediment transport due to subtidal and subaerial processes

  7. From gravel to sand. Downstream fining of bed sediments in the lower river Rhine

    NARCIS (Netherlands)

    Frings, R.M.

    2007-01-01

    A common characteristic of many rivers is the tendency for bed sediments to become finer in downstream direction. This phenomenon, which is generally known as downstream fining, has a strong effect on the morphologic and hydrodynamic behaviour of a river. The fundamental causes of downstream

  8. Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays

    NARCIS (Netherlands)

    Wang, J.; Bovee, T.F.H.; Bi, Y.; Bernhöft, S.; Schramm, K.W.

    2014-01-01

    Two types of biological tests were employed for monitoring the toxicological profile of sediment cores in the Three Gorges Reservoir (TGR), China. In the present study, sediments collected in June 2010 from TGR were analyzed for estrogen receptor (ER)- and aryl hydrocarbon receptor (AhR)-mediated

  9. Parametric study of the physical properties of hydrate-bearing sand, silt, and clay sediments: 1. Electromagnetic properties

    Science.gov (United States)

    Lee, J.Y.; Santamarina, J.C.; Ruppel, C.

    2010-01-01

    The marked decrease in bulk electrical conductivity of sediments in the presence of gas hydrates has been used to interpret borehole electrical resistivity logs and, to a lesser extent, the results of controlled source electromagnetic surveys to constrain the spatial distribution and predicted concentration of gas hydrate in natural settings. Until now, an exhaustive laboratory data set that could be used to assess the impact of gas hydrate on the electromagnetic properties of different soils (sand, silt, and clay) at different effective stress and with different saturations of hydrate has been lacking. The laboratory results reported here are obtained using a standard geotechnical cell and the hydrate-formed tetrahydrofuran (THF), a liquid that is fully miscible in water and able to produce closely controlled saturations of hydrate from dissolved phase. Both permittivity and electrical conductivity are good indicators of the volume fraction of free water in the sediment, which is in turn dependent on hydrate saturation. Permittivity in the microwave frequency range is particularly predictive of free water content since it is barely affected by ionic concentration, pore structure, and surface conduction. Electrical conductivity (or resistivity) is less reliable for constraining water content or hydrate saturation: In addition to fluid-filled porosity, other factors, such as the ionic concentration of the pore fluid and possibly other conduction effects (e.g., surface conduction in high specific surface soils having low conductivity pore fluid), also influence electrical conductivity.

  10. Gas-hydrate-bearing sand reservoir systems in the offshore of India: Results of the India National Gas Hydrate Program Expedition 02

    Science.gov (United States)

    Kumar, P.; Collett, Timothy S.; Vishwanath, K.; Shukla, K.M.; Nagalingam, J.; Lall, M.V.; Yamada, Y; Schultheiss, P.; Holland, M.

    2016-01-01

    The India National Gas Hydrate Program Expedition 02 (NGHP-02) was conducted from 3-March-2015 to 28-July-2015 off the eastern coast of India using the deepwater drilling vessel Chikyu. The primary goal of this expedition was to explore for highly saturated gas hydrate occurrences in sand reservoirs that would become targets for future production tests. The first two months of the expedition were dedicated to logging-whiledrilling (LWD) operations, with a total of 25 holes drilled and logged. The next three months were dedicated to coring operations at 10 of the most promising sites. With a total of five months of continuous field operations, the expedition was the most comprehensive dedicated gas hydrate investigation ever undertaken.

  11. Stonemeal of Amazon soils with sediments from reservoirs: a case study of remineralization of the Tucuruí degraded land for agroforest reclamation.

    Science.gov (United States)

    Theodoro, Suzi H; Leonardos, Othon H; Rocha, Eduardo; Macedo, Iris; Rego, Kleysson G

    2013-03-01

    This study suggests the employment of accumulated sediments in the reservoir of Tucuruí (Pará /Brazil) to remineralize the surrounding degraded soils. The approach was based on the principles of stonemeal technology. It suggests that the soil can be rejuvenated by crushed rocks rich in macro and micronutrients. Removal of the sediments for agricultural use will bring benefits to family farmers and increase the life cycle of the reservoir and, therefore, energy generation. Geochemical data on retained sediments, soils and rocks in the area of influence of the reservoir were evaluated regarding nutrient transport mechanisms and soil-fertility potential. Results show that sediments from the reservoir contain nutrients levels at least one order of magnitude greater than average Amazon region soils. Our data on soil use and occupation in the region show the degradation areas which could be recovered by stonemeal techniques. Thence, an Agroforestry System was installed, with 12 plots where different mixtures of sediments removed from the reservoir were used, along with crushed rock with or without the addition of NPK and manure. The experiments showed that maximum crop yield and plant growth were attained in the plots where a mixture of sediments, crushed rocks and manure were added.

  12. Stonemeal of amazon soils with sediments from reservoirs: a case study of remineralization of the tucuruí degraded land for agroforest reclamation

    Directory of Open Access Journals (Sweden)

    SUZI H. THEODORO

    2013-03-01

    Full Text Available This study suggests the employment of accumulated sediments in the reservoir of Tucuruí (Pará /Brazil to remineralize the surrounding degraded soils. The approach was based on the principles of stonemeal technology. It suggests that the soil can be rejuvenated by crushed rocks rich in macro and micronutrients. Removal of the sediments for agricultural use will bring benefits to family farmers and increase the life cycle of the reservoir and, therefore, energy generation. Geochemical data on retained sediments, soils and rocks in the area of influence of the reservoir were evaluated regarding nutrient transport mechanisms and soil-fertility potential. Results show that sediments from the reservoir contain nutrients levels at least one order of magnitude greater than average Amazon region soils. Our data on soil use and occupation in the region show the degradation areas which could be recovered by stonemeal techniques. Thence, an Agroforestry System was installed, with 12 plots where different mixtures of sediments removed from the reservoir were used, along with crushed rock with or without the addition of NPK and manure. The experiments showed that maximum crop yield and plant growth were attained in the plots where a mixture of sediments, crushed rocks and manure were added.

  13. Radionuclides in intertidal sands and sediments from Morecambe Bay to the Dee estuary

    International Nuclear Information System (INIS)

    Carpenter, R.C.; Burton, P.J.; Strange, L.P.; Pratley, F.W.

    1991-05-01

    Surface and core samples of intertidal sediments have been collected from the coastline from Morecambe Bay to the Dee Estuary. The sampling took place between October 1987 and July 1989. Caesium-137 was determined by high resolution gamma spectrometry and plutonium isotopes and americium-241 were determined by alpha spectrometry following radiochemical separations. Samples were also sieved to obtain a particle size distribution of the deposits. A wide range of radionuclide activities have been determined depending on the distance from Sellafield and, more importantly, the proportion of clay plus silt ( 239+240 Pu and 241 Am activity discharged by Sellafield up to the end of 1988. The measured activities generally represent a small fraction of the Generalised Derived Limits (GDL's) for marine sediments. (author)

  14. Sedimentary record of water column trophic conditions and sediment carbon fluxes in a tropical water reservoir (Valle de Bravo, Mexico).

    Science.gov (United States)

    Carnero-Bravo, Vladislav; Merino-Ibarra, Martín; Ruiz-Fernández, Ana Carolina; Sanchez-Cabeza, Joan Albert; Ghaleb, Bassam

    2015-03-01

    Valle de Bravo (VB) is the main water reservoir of the Cutzamala hydraulic system, which provides 40% of the drinking water consumed in the Mexico City Metropolitan Area and exhibits symptoms of eutrophication. Nutrient (C, N and P) concentrations were determined in two sediment cores to reconstruct the water column trophic evolution of the reservoir and C fluxes since its creation in 1947. Radiometric methods ((210)Pb and (137)Cs) were used to obtain sediment chronologies, using the presence of pre-reservoir soil layers in one of the cores as an independent chronological marker. Mass accumulation rates ranged from 0.12 to 0.56 g cm(-2) year(-1) and total organic carbon (TOC) fluxes from 122 to 380 g m(-2) year(-1). Total N ranged 4.9-48 g m(-2) year(-1), and total P 0.6-4.2 g m(-2) year(-1). The sedimentary record shows that all three (C, N and P) fluxes increased significantly after 1991, in good agreement with the assessed trophic evolution of VB and with historic and recent real-time measurements. In the recent years (1992-2006), the TOC flux to the bottom of VB (average 250 g m(-2) year(-1), peaks 323 g m(-2) year(-1)) is similar to that found in highly eutrophic reservoirs and impoundments. Over 1/3 of the total C burial since dam construction, circa 70,000 t, has occurred in this recent period. These results highlight the usefulness of the reconstruction of carbon and nutrient fluxes from the sedimentary record to assess carbon burial and its temporal evolution in freshwater ecosystems.

  15. Parcperdue geopressure-geothermal project. Study a geopressured reservoir by drilling and producing a well in a limited geopressured water sand. Final technical report, September 28, 1979-December 31, 1983

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, J.R.; Stanley, J.G. (eds.)

    1984-01-15

    The behavior of geopressured reservoirs was investigated by drilling and producing a well in small, well defined, geopressured reservoir; and performing detailed pressure transient analysis together with geological, geophysical, chemical, and physical studies. The Dow-DOE L. R. Sweezy No. 1 well was drilled to a depth of 13,600 feet in Parcperdue field, just south of Lafayette, Louisiana, and began production in April, 1982. The production zone was a poorly consolidated sandstone which constantly produced sand into the well stream, causing damage to equipment and causing other problems. The amount of sand production was kept manageable by limiting the flow rate to below 10,000 barrels per day. Reservoir properties of size, thickness, depth, temperature, pressure, salinity, porosity, and permeability were close to predicted values. The reservoir brine was undersaturated with respect to gas, containing approximately 20 standard cubic feet of gas per barrel of brine. Shale dewatering either did not occur or was insignificant as a drive mechanism. Production terminated when the gravel-pack completion failed and the production well totally sanded in, February, 1983. Total production up to the sanding incident was 1.94 million barrels brine and 31.5 million standard cubic feet gas.

  16. [Pollution characteristics and ecological risk assessment of heavy metals in surface sediments of Qingshan Reservoir in Lin' an City, Zhejiang Province of East China].

    Science.gov (United States)

    Zhang, Fen; Yang, Chang-Ming; Pan, Rui-Jie

    2013-09-01

    A total of 8 representative surface sediment sampling sites were collected from the Qingshan Reservoir in Lin'an City of Zhejiang Province to investigate the differences in the total concentrations of As, Cr, Cu, Ni, Mn, Pb, and Zn among the sampling sites. The different forms of the heavy metals, i. e., acid soluble, easily reducible, easily oxidizable, and residual, were determined by BCR sequential extraction method, and the pollution degrees and potential ecological risk, of the heavy metals in the surface sediments at different sampling sites of the Reservoir were assessed by using geo-accumulation index (I(geo)) and Hakanson potential ecological risk index. There existed obvious spatial differences in the total concentrations of the heavy metals in the surface sediments of the Reservoir. The sampling sites nearby the estuaries of the tributaries flowing through downtowns and heavy industrial parks to the Reservoir had obviously higher heavy metals concentrations in surface sediments, as compared to the other sampling sites. In the sediments, Mn was mainly in acid extractable form, Cu and Pb were mainly in reducible form, and As was mainly in residual form. The surface sediments at the sampling sites nearby the estuaries of the tributaries flowing through downtowns to the Reservoir had higher proportions of acid extractable and reducibles forms of the heavy metals, which would have definite potential toxic risk to aquatic organisms. Among the 7 heavy metals in the surface sediments, As showed the highest pollution degree, followed by Cu, Ni, Mn, Pb, and Zn, which were at moderate pollution degree, while Cr was at non-pollution degree, with relatively low potential ecological risk. Through the comparison of the sampling sites, it was observed that the surface sediments at the sites nearby the estuaries of Jinxi River and Hengxi River flowing through downtowns and heavy industrial parks to the Reservoir showed obviously higher heavy metals pollution degree and

  17. Genesis and continuity of quaternary sand and gravel in glacigenic sediment at a proposed low-level radioactive waste disposal site in east-central Illinois

    Science.gov (United States)

    Troost, K.G.; Curry, B. Brandon

    1991-01-01

    The Illinois Department of Nuclear Safety has characterized the Martinsville Alternative Site (MAS) for a proposed low-level radioactive waste disposal facility. The MAS is located in east-central Illinois approximately 1.6 km (1 mi) north of the city of Martinsville. Geologic investigation of the 5.5-km2 (1380-acre) site revealed a sequence of chiefly Illinoian glacigenic sediments from 6 to 60 m (20-200 ft) thick overlying two major bedrock valleys carved in Pennsylvanian strata. Relatively permeable buried units include basal, preglacial alluvium; a complex of intraglacial and subglacial sediment; englacial deposits; and supraglacial fluvial deposits. Postglacial alluvium underlies stream valleys on and adjacent to the site. In most areas, the buried sand units are confined by low-permeability till, lacustrine sediment, colluvium, and loess. The distribution and thickness of the most extensive and continuous buried sand units have been modified considerably by subglacial erosion, and their distributions have been influenced by the buried bedrock valleys. The most continuous of the various sand units were deposited as preglacial and postglacial alluvium and are the uppermost and lowermost stratigraphic units at the alternative site. Sand units that were deposited in englacial or ice-marginal environments are less continuous. Aquifer pumping tests, potentiometric head data, and groundwater geochemistry analyses indicate minimal interaction of groundwater across localized interconnections of the permeable units. ?? 1991 Springer-Verlag New York Inc.

  18. A gel probe equilibrium sampler for measuring arsenic porewater profiles and sorption gradients in sediments: II. Field application to Haiwee reservoir sediment

    Science.gov (United States)

    Campbell, K.M.; Root, R.; O'Day, P. A.; Hering, J.G.

    2008-01-01

    Arsenic (As) geochemistry and sorption behavior were measured in As- and iron (Fe)-rich sediments of Haiwee Reservoir by deploying undoped (clear) polyacrylamide gels and hydrous ferric oxide (HFO)-doped gels in a gel probe equilibrium sampler, which is a novel technique for directly measuring the effects of porewater composition on As adsorption to Fe oxides phases in situ. Arsenic is deposited at the sediment surface as As(V) and is reduced to As(III) in the upper layers of the sediment (0-8 cm), but the reduction of As(V) does not cause mobilization into the porewater. Dissolved As and Fe concentrations increased at depth in the sediment column driven by the reductive dissolution of amorphous Fe(III) oxyhydroxides and conversion to a mixed Fe(II, III) green rust-type phase. Adsorption of As and phosphorous (P) onto HFO-doped gels was inhibited at intermediate depths (10-20 cm), possibly due to dissolved organic or inorganic carbon, indicating that dissolved As concentrations were at least partially controlled by porewater composition rather than surface site availability. In sediments that had been recently exposed to air, the region of sorption inhibition was not observed, suggesting that prior exposure to air affected the extent of reductive dissolution, porewater chemistry, and As adsorption behavior. Arsenic adsorption onto the HFO-doped gels increased at depths >20 cm, and the extent of adsorption was most likely controlled by the competitive effects of dissolved phosphate. Sediment As adsorption capacity appeared to be controlled by changes in porewater composition and competitive effects at shallower depths, and by reductive dissolution and availability of sorption sites at greater burial depths. ?? 2008 American Chemical Society.

  19. 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.

  20. Atmospheric pollution history at Linfen (China) uncovered by magnetic and chemical parameters of sediments from a water reservoir.

    Science.gov (United States)

    Ma, Mingming; Hu, Shouyun; Cao, Liwan; Appel, Erwin; Wang, Longsheng

    2015-09-01

    We studied magnetic and chemical parameters of sediments from sediments of a water reservoir at Linfen (China) in order to quantitatively reconstruct the atmospheric pollution history in this region. The results show that the main magnetic phases are magnetite and maghemite originating from the surrounding catchment and from anthropogenic activities, and there is a significant positive relationship between magnetic concentration parameters and heavy metals concentrations, indicating that magnetic proxies can be used to monitor the anthropogenic pollution. In order to uncover the atmospheric pollution history, we combined the known events of environmental improvement with variations of magnetic susceptibility (χ) and heavy metals along the cores to obtain a detailed chronological framework. In addition, air comprehensive pollution index (ACPI) was reconstructed from regression equation among magnetic and chemical parameters as well as atmospheric monitoring data. Based on these results, the atmospheric pollution history was successfully reconstructed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Cyclicity and reservoir properties of Lower-Middle Miocene sediments of South Kirinsk oil and gas field

    Science.gov (United States)

    Kurdina, Nadezhda

    2017-04-01

    Exploration and additional exploration of oil and gas fields, connected with lithological traps, include the spreading forecast of sedimentary bodies with reservoir and seal properties. Genetic identification and forecast of geological bodies are possible in case of large-scale studies, based on the study of cyclicity, structural and textural features of rocks, their composition, lithofacies and depositional environments. Porosity and permeability evaluation of different reservoir groups is also an important part. Such studies have been successfully completed for productive terrigenous Dagi sediments (Lower-Middle Miocene) of the north-eastern shelf of Sakhalin. In order to identify distribution of Dagi reservoirs with different properties in section, core material of the one well of South Kirinsk field has been studied (depth interval from 2902,4 to 2810,5 m). Productive Dagi deposits are represented by gray-colored sandstones with subordinate siltstones and claystones (total thickness 90,5 m). Analysis of cyclicity is based on the concepts of Vassoevich (1977), who considered cycles as geological body, which is the physical result of processes that took place during the sedimentation cycle. Well section was divided into I-X units with different composition and set of genetic features due to layered core description and elementary cyclites identification. According to description of thin sections and results of cylindrical samples porosity and permeability studies five groups of reservoirs were determined. There are coarse-grained and fine-coarse-grained sandstones, fine-grained sandstones, fine-grained silty sandstones, sandy siltstones and siltstones. It was found, in Dagi section there is interval of fine-coarse-grained and coarse-grained sandstones with high petrophysical properties: permeability 3000 mD, porosity more than 25%, but rocks with such properties spread locally and their total thickness is 6 meters only. This interval was described in the IV unit

  2. Heavy metal contamination in sand and sediments near to disposal site of reject brine from desalination plant, Arabian Gulf: Assessment of environmental pollution.

    Science.gov (United States)

    Alshahri, Fatimh

    2017-01-01

    Accumulation of heavy metals in environment may cause series potential risk in the living system. This study was carried out to investigate heavy metal contamination in sand samples and sediments along the beach near to disposal site of reject brine from Alkhobar desalination plant, which is one of the oldest and largest reverse osmosis desalination plants in eastern Saudi Arabia, Arabian Gulf. Fourteen heavy metals (U, Ca, Fe, Al, Ti, Sr, Rb, Ni, Pb, Cd, Cr, Cu, As, and Zr) were measured using gamma-ray spectrometry, atomic absorption spectrometer (AAS) and energy dispersive X-ray fluorescence spectrometer (EDX). The obtained data revealed that the concentrations of these metals were higher than the values in sediment and soil for other studies in Arabian Gulf. Furthermore, the mean values of Fe, Mn, Cr, Cu, As, Sr, and Zr concentrations in sand and sediments were higher than the geochemical background values in shale. The contamination factor (CF), modified degree of contamination (mC d ) and pollution load index (PLI) were assessed. According to contamination factors (CF > 1), the results showed elevated levels of Cu, Cr, Mn, Zr, and As in all samples. The highest value of contamination factor was found for As. Based on PLI (PLI > 1), the values of all sampling sites indicate a localized pollution in the study area. Current study could be useful as baseline data for heavy metals in sand and sediments nearby a desalination plant.

  3. The Application of a Multi-Beam Echo-Sounder in the Analysis of the Sedimentation Situation of a Large Reservoir after an Earthquake

    Directory of Open Access Journals (Sweden)

    Zhong-Luan Yan

    2018-04-01

    Full Text Available The Wenchuan Earthquake took place in the upper reach catchment of the Min River. It resulted in large amounts of loose materials gathering in the river channel, leading to changes in the sediment transport system in this area. The Zipingpu Reservoir is the last and the largest reservoir located in the upper reach of the Min River. It is near the epicenter and receives sediment from upstream. This paper puts forward a study on the reservoir sedimentation and storage capacity of the Zipingpu Reservoir, employing a multi-beam echo-sounder system in December 2012. Then, the data were merged with digital line graphics and shuttle radar topography mission data in ArcGIS to build a digital elevation model and triangulate the irregular network of Zipingpu Reservoir. Via the analysis of the bathymetric data, the results show the following: (1 The main channels of the reservoir gradually aggrade to a flat bottom from the deep-cutting valley. Sedimentation forms a reach with a W-shaped longitudinal thalweg profile and an almost zero slope reach in the upstream section of the reservoir due to the natural barrier induced by a landslide; (2 The loss ratios of the wetted cross-section surface are higher than 10% in the upstream section of the reservoir and higher than 40% in the natural barrier area; (3 Comparing the surveyed area storage capacity of December 2012 with March 2008, the Zipingpu Reservoir has lost 15.28% of its capacity at the dead storage water level and 10.49% of its capacity at the flood limit water level.

  4. Rapid reservoir erosion, hyperconcentrated flow, and downstream deposition triggered by breaching of 38 m tall Condit Dam, White Salmon River, Washington

    Science.gov (United States)

    Wilcox, Andrew C.; O'Connor, James E.; Major, Jon J.

    2014-01-01

    Condit Dam on the White Salmon River, Washington, a 38 m high dam impounding a large volume (1.8 million m3) of fine-grained sediment (60% sand, 35% silt and clay, and 5% gravel), was rapidly breached in October 2011. This unique dam decommissioning produced dramatic upstream and downstream geomorphic responses in the hours and weeks following breaching. Blasting a 5 m wide hole into the base of the dam resulted in rapid reservoir drawdown, abruptly releasing ~1.6 million m3 of reservoir water, exposing reservoir sediment to erosion, and triggering mass failures of the thickly accumulated reservoir sediment. Within 90 min of breaching, the reservoir's water and ~10% of its sediment had evacuated. At a gauging station 2.3 km downstream, flow increased briefly by 400 m3 s−1during passage of the initial pulse of released reservoir water, followed by a highly concentrated flow phase—up to 32% sediment by volume—as landslide-generated slurries from the reservoir moved downstream. This hyperconcentrated flow, analogous to those following volcanic eruptions or large landslides, draped the downstream river with predominantly fine sand. During the ensuing weeks, suspended-sediment concentration declined and sand and gravel bed load derived from continued reservoir erosion aggraded the channel by >1 m at the gauging station, after which the river incised back to near its initial elevation at this site. Within 15 weeks after breaching, over 1 million m3 of suspended load is estimated to have passed the gauging station, consistent with estimates that >60% of the reservoir's sediment had eroded. This dam removal highlights the influence of interactions among reservoir erosion processes, sediment composition, and style of decommissioning on rate of reservoir erosion and consequent downstream behavior of released sediment.

  5. Trace metals and persistent organic pollutants in sediments from river-reservoir systems in Democratic Republic of Congo (DRC): Spatial distribution and potential ecotoxicological effects.

    Science.gov (United States)

    Mwanamoki, Paola M; Devarajan, Naresh; Thevenon, Florian; Birane, Niane; de Alencastro, Luiz Felippe; Grandjean, Dominique; Mpiana, Pius T; Prabakar, Kandasamy; Mubedi, Josué I; Kabele, Christophe G; Wildi, Walter; Poté, John

    2014-09-01

    This paper discusses the occurrence and spatial distribution of metals and persistent organic pollutants (POPs: including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), Polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) in sediments from a river-reservoir system. Surface sediments were sampled from thirteen sites of the Congo River Basin and Lake Ma Vallée, both situated in the vicinity of the capital city Kinshasa (Congo Democratic Republic). Sediment qualities were evaluated using toxicity test based on exposing Ostracods to the sediment samples. The highest metal concentrations were observed in sediments subjected to anthropogenic influences, urban runoff and domestic and industrial wastewaters, discharge into the Congo River basin. Ostracods exposed to the sediments resulted in 100% mortality rates after 6d of incubation, indicating the ultimate toxicity of these sediments as well as potential environmental risks. The POPs and PAHs levels in all sediment samples were low, with maximum concentration found in the sediments (area of pool Malebo): OCP value ranged from 0.02 to 2.50 with ∑OCPs: 3.3μgkg(-1); PCB ranged from 0.07 to 0.99 with Total PCBs (∑7×4.3): 15.31μgkg(-1); PAH value ranged from 0.12 to 9.39 with ∑PAHs: 63.89μgkg(-1). Our results indicate that the deterioration of urban river-reservoir water quality result mainly from urban stormwater runoff, untreated industrial effluents which discharge into the river-reservoirs, human activities and uncontrolled urbanization. This study represents useful tools incorporated to evaluate sediment quality in river-reservoir systems which can be applied to similar aquatic environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Enrichment factor and geoaccumulation index applied to sediment samples from the Guarapiranga reservoir, Brazil, for metal and trace element assessment

    International Nuclear Information System (INIS)

    Guimaraes, Guilherme M.; Figueiredo, Ana M.G.; Silva, Paulo S.C.; Favaro, Deborah I.; Franklin, Robson L.

    2011-01-01

    This study aims to assess sediment contamination by metals and other trace elements in five sampling points of the Guarapiranga Reservoir. Two collection campaigns were undertaken and the samples were analyzed by Instrumental Neutron Activation Analysis (INAA) in order to determine the following elements: major (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Rb, Sb , Sc, Ta, Tb, Th, U and Zn) and rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu). Soil samples were collected in the Guarapiranga Park, located next to the reservoir. Composite top soil samples (0-20 cm) were collected in lines across the park at every 30m and were also analyzed by INAA. EF values was calculated using Sc as the conservative element for normalization purposes and soil from Guarapiranga region was used as background levels for the elements analyzed. EF > 1.5 were obtained for the elements As, Sb and Zn, with highest values for Zn (1.6< EF<4.0), mainly at sampling points near the water supply catchment point from the Water Treatment Agency of Sao Paulo State, indicating anthropogenic contribution. As for the other elements, a 0.5< EF<1.0 was obtained, indicating that they mostly originate from crustal contribution. The Igeo Index was calculated using soil values as background or pristine values as well. For Zn, Igeo values (1.0< EF<2.0) were obtained, and, according to this criteria, these sediments can be classified as moderately contaminated. (author)

  7. Enrichment factor and geoaccumulation index applied to sediment samples from the Guarapiranga reservoir, Brazil, for metal and trace element assessment

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Guilherme M.; Figueiredo, Ana M.G.; Silva, Paulo S.C.; Favaro, Deborah I., E-mail: defavaro@ipen.b, E-mail: anamaria@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica; Franklin, Robson L., E-mail: robsonf@cetesbnet.sp.gov.b [Companhia de Tecnologia de Saneamento Ambiental (EAAI/CETESB), Sao Paulo, SP (Brazil). Lab. de Quimica Inorganica e Radioatividade

    2011-07-01

    This study aims to assess sediment contamination by metals and other trace elements in five sampling points of the Guarapiranga Reservoir. Two collection campaigns were undertaken and the samples were analyzed by Instrumental Neutron Activation Analysis (INAA) in order to determine the following elements: major (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Rb, Sb , Sc, Ta, Tb, Th, U and Zn) and rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu). Soil samples were collected in the Guarapiranga Park, located next to the reservoir. Composite top soil samples (0-20 cm) were collected in lines across the park at every 30m and were also analyzed by INAA. EF values was calculated using Sc as the conservative element for normalization purposes and soil from Guarapiranga region was used as background levels for the elements analyzed. EF > 1.5 were obtained for the elements As, Sb and Zn, with highest values for Zn (1.6sediments can be classified as moderately contaminated. (author)

  8. Pollution characteristics and ecological risk assessment of heavy metals in the surface sediments from a source water reservoir

    Directory of Open Access Journals (Sweden)

    Changming Yang

    2016-10-01

    Full Text Available Surface sediment samples were collected from a source water reservoir in Zhejiang Province, East of China to investigate pollution characteristics and potential ecological risk of heavy metals. The BCR sequential extraction method was used to determine the four chemical fractions of heavy metals such as acid soluble, easily reducible, easily oxidizable and residual fractions. The heavy metals pollution and potential ecological risk were evaluated systematically using geoaccumulation index (Igeo and Hakanson potential ecological risk index (H′. The results showed that the sampling sites from the estuaries of tributary flowing through downtowns and heavy industrial parks showed significantly (p < 0.05 higher average concentrations of heavy metals in the surface sediments, as compared to the other sampling sites. Chemical fractionation showed that Mn existed mainly in acid extractable fraction, Cu and Pb were mainly in reducible fraction, and As existed mainly in residual fraction in the surface sediments despite sampling sites. The sampling sites from the estuary of tributary flowing through downtown showed significantly (p < 0.05 higher proportions of acid extractable and reducible fractions than the other sampling sites, which would pose a potential toxic risk to aquatic organisms as well as a potential threat to drinking water safety. As, Pb, Ni and Cu were at relatively high potential ecological risk with high Igeo values for some sampling locations. Hakanson potential ecological risk index (H′ showed the surface sediments from the tributary estuaries with high population density and rapid industrial development showed significantly (p < 0.05 higher heavy metal pollution levels and potential ecological risk in the surface sediments, as compared to the other sampling sites.

  9. Early invasion population structure of quagga mussel and associated benthic invertebrate community composition on soft sediment in a large reservoir

    Science.gov (United States)

    Wittmann, Marion E.; Chandra, Sudeep; Caires, Andrea; Denton, Marianne; Rosen, Michael R.; Wong, Wai Hing; Teitjen, Todd; Turner, Kent; Roefer, Peggy; Holdren, G. Chris

    2010-01-01

    In 2007 an invasive dreissenid mussel species, Dreissena bugensis (quagga mussel), was discovered in Lake Mead reservoir (AZ–NV). Within 2 years, adult populations have spread throughout the lake and are not only colonizing hard substrates, but also establishing in soft sediments at depths ranging from 1 to >100 m. Dreissena bugensis size class and population density distribution differs between basins; cluster analysis revealed 5 adult cohorts within Boulder Basin and Overton Arm but low densities and low cohort survival in the Las Vegas Basin. Regression analysis suggests depth and temperature are not primary controllers of D. bugensis density in Lake Mead, indicating other factors such as sediment type, food availability or other resource competition may be important. Monthly veliger tows showed at least 2 major spawning events per year, with continuous presence of veligers in the water column. Adult mussels have been found in spawn or post-spawn condition in soft sediments in shallow to deep waters (>80 m) indicating the potential for reproduction at multiple depths. Comparisons to a 1986 benthic survey suggest there have been shifts in nondreissenid macroinvertebrate composition; however, it is unclear if this is due to D. bugensis presence. Current distribution of nondreissenid macroinvertebrates is heterogeneous in all 3 basins, and their biodiversity decreased when D. bugensis density was 2500/m2 or greater.

  10. Reservoir-flooded river mouth areas as sediment traps revealing erosion from peat mining areas - Jukajoki case study in eastern Finland

    Science.gov (United States)

    Tahvanainen, Teemu; Meriläinen, Henna-Kaisa; Haraguchi, Akira; Simola, Heikki

    2016-04-01

    Many types of soil-disturbing land use have caused excess sedimentation in Finnish lakes. Identification and quantification of catchment sources of sediment material is crucial in cases where demands for remediation measures are considered. We studied recent (50 yr) sediments of four small rivers, all draining to a reservoir impounded in 1971. Catchments of two of the rivers had had peat mining activities from early 1980s until recently, exposing large areas of peat surfaces to erosion. The water level of the reservoir had risen to the river mouth areas of all rivers, while in each case, the river mouth areas still form riverine narrows separable from the main reservoir, hence collecting sedimentation from their own catchments. The original soils under the reservoir water level could readily be observed in core samples, providing a dated horizon under recent sediments. In addition, we used 137Cs-stratigraphies for dating of samples from original river bed locations. As expected, recent sediments of rivers with peat mining influence differed from others e.g. by high organic content and C:N ratios. Stable isotopes 13C and 15N both correlated with C:N (r = 0.799 and r = -0.717, respectively) and they also differentiated the peat-mining influenced samples from other river sediments. Principal components of the physical-chemical variables revealed clearer distinction than any variables separately. Light-microscopy revealed abundance of leafs of Sphagnum mosses in peat-mining influenced river sediments that were nearly absent from other rivers. Spores of Sphagnum were, however, abundant in all river sediments indicating their predominantly airborne origin. We find that combination of several physical-chemical characters rather than any single variable and microscopy of plant remains can result in reliable recognition of peatland-origin of sediment material when non-impacted sites are available for comparison. Dating of disturbed recent sediments is challenging. River

  11. Qualitative simulation of bathymetric changes due to reservoir sedimentation: A Japanese case study.

    Directory of Open Access Journals (Sweden)

    Ahmed Bilal

    Full Text Available Sediment-dynamics modeling is a useful tool for estimating a dam's lifespan and its cost-benefit analysis. Collecting real data for sediment-dynamics analysis from conventional field survey methods is both tedious and expensive. Therefore, for most rivers, the historical record of data is either missing or not very detailed. Available data and existing tools have much potential and may be used for qualitative prediction of future bathymetric change trend. This study shows that proxy approaches may be used to increase the spatiotemporal resolution of flow data, and hypothesize the river cross-sections and sediment data. Sediment-dynamics analysis of the reach of the Tenryu River upstream of Sakuma Dam in Japan was performed to predict its future bathymetric changes using a 1D numerical model (HEC-RAS. In this case study, only annually-averaged flow data and the river's longitudinal bed profile at 5-year intervals were available. Therefore, the other required data, including river cross-section and geometry and sediment inflow grain sizes, had to be hypothesized or assimilated indirectly. The model yielded a good qualitative agreement, with an R2 (coefficient of determination of 0.8 for the observed and simulated bed profiles. A predictive simulation demonstrated that the useful life of the dam would end after the year 2035 (±5 years, which is in conformity with initial detailed estimates. The study indicates that a sediment-dynamic analysis can be performed even with a limited amount of data. However, such studies may only assess the qualitative trends of sediment dynamics.

  12. Qualitative simulation of bathymetric changes due to reservoir sedimentation: A Japanese case study.

    Science.gov (United States)

    Bilal, Ahmed; Dai, Wenhong; Larson, Magnus; Beebo, Qaid Naamo; Xie, Qiancheng

    2017-01-01

    Sediment-dynamics modeling is a useful tool for estimating a dam's lifespan and its cost-benefit analysis. Collecting real data for sediment-dynamics analysis from conventional field survey methods is both tedious and expensive. Therefore, for most rivers, the historical record of data is either missing or not very detailed. Available data and existing tools have much potential and may be used for qualitative prediction of future bathymetric change trend. This study shows that proxy approaches may be used to increase the spatiotemporal resolution of flow data, and hypothesize the river cross-sections and sediment data. Sediment-dynamics analysis of the reach of the Tenryu River upstream of Sakuma Dam in Japan was performed to predict its future bathymetric changes using a 1D numerical model (HEC-RAS). In this case study, only annually-averaged flow data and the river's longitudinal bed profile at 5-year intervals were available. Therefore, the other required data, including river cross-section and geometry and sediment inflow grain sizes, had to be hypothesized or assimilated indirectly. The model yielded a good qualitative agreement, with an R2 (coefficient of determination) of 0.8 for the observed and simulated bed profiles. A predictive simulation demonstrated that the useful life of the dam would end after the year 2035 (±5 years), which is in conformity with initial detailed estimates. The study indicates that a sediment-dynamic analysis can be performed even with a limited amount of data. However, such studies may only assess the qualitative trends of sediment dynamics.

  13. Bioturbation/bioirrigation effect on thallium released from reservoir sediment by different organism types.

    Science.gov (United States)

    He, Yi; Men, Bin; Yang, Xiaofang; Wang, Dongsheng

    2015-11-01

    Bioturbation can remobilize heavy metal in the sediments and may pose a risk for aquatic biota. The effects of bioturbation/bioirrigation by three different riverine organism types (Tubificid, Chironomid larvae, and Loach) on thallium release from contaminated sediment (10.0 ± 1.1 mg Tl/kg sediment, dry wt.) were evaluated in this study. The bioturbation by the epibenthos clearly caused an increased turbidity in the overlying water, and the effect was in the order of Loach > Chironomid larvae > Tubificid. A significant release of Tl into the water column via the resuspended sediment particles was observed, especially for Loach. During the first few days, the leaching of dissolved Tl from sediment into water was fast, and the dissolved Tl under bioturbation/bioirrigation was much higher than the control group. However, after 14 days, the bioturbation/bioirrigation process seemed to suppress the release of Tl from the sediment particles to water, especially for sediment with Loach. This may partly be due to the sorption or coprecipitation of Tl simultaneous with the formation of iron and manganese hydrous oxides with increased pH values as a consequence of phytoplankton growth. Linear regression analysis confirmed that both the total and particulate Tl concentrations had good correlations with particulate Fe and Mn concentrations as well as turbidity in the overlying water. Additionally, planktonic bacteria may oxidize the Tl(I) to Tl(III), resulting in a reduced solubility of Tl by which Tl(OH)3 becomes the predominant form of Tl. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Sediment and 137Cs transport and accumulation in the Ogaki Dam of eastern Fukushima

    International Nuclear Information System (INIS)

    Yamada, Susumu; Malins, Alex; Machida, Masahiko; Kitamura, Akihiro; Kurikami, Hiroshi; Yamaguchi, Masaaki

    2015-01-01

    The Ogaki Dam Reservoir is one of the principal irrigation dam reservoirs in the Fukushima Prefecture and its upstream river basin was heavily contaminated by radioactivity from the Fukushima Daiichi Nuclear Power Plant accident. For the purpose of environmental assessment, it is important to determine the present condition of the water in the reservoir and to understand the behavior of sediment-sorbed radioactive cesium under different modes of operation of the dam, as these factors affect further contamination of arable farmlands downstream of the reservoir through sediment migration. This paper addresses this issue with numerical simulations of fluvial processes in the reservoir using the two-dimensional Nays2D code. We distinguish three grades of sediment (clay, silt, and sand), as cesium adherence depends on sediment grain size and surface area. Boundary conditions for the simulations were informed by monitoring data of the upstream catchment and by the results from a separate watershed simulation for sediment transport into the reservoir. The performance of the simulation method was checked by comparing the results for a typhoon flood in September 2013 against field monitoring data. We present results for sediment deposition on the reservoir bed and the discharge via the dam under typical yearly flood conditions, for which the bulk of annual sediment migration from the reservoir occurs. The simulations show that almost all the sand and silt that enter into the reservoir deposit onto the reservoir bed. However, the locations where they tend to deposit differ, with sand tending to deposit close to the entrance of the reservoir, whereas silt deposits throughout the reservoir. Both sand and silt settle within a few hours of entering the reservoir. In contrast, clay remains suspended in the reservoir water for a period as long as several days, thus increasing the amount that is discharged downstream from the reservoir. Under the current operating mode of the dam

  15. Using Nd-Sr isotopes and rare earth elements to study sediment provenance of the modern radial sand ridges in the southwestern Yellow Sea

    International Nuclear Information System (INIS)

    Rao, Wenbo; Mao, Changping; Wang, Yigang; Huang, Huiming; Ji, Junfeng

    2017-01-01

    The radial sand ridges (RSRs) in the southwestern Yellow Sea off the Jiangsu Coast, East China have been intensively studied at least since 1975. Despite decades of studies, the provenance of the RSR sediments remains uncertain. In this study, the Nd-Sr isotopic and REE geochemical compositions of residual sediments (i.e., the acid-insoluble fractions) were investigated to determine the provenance of the RSR sediments. The Nd isotopic composition, PAAS-normalized REE patterns and characteristic parameters (e.g., Sm/Nd, (La/Sm)_N, (Gd/Yb)_N) were merely associated with source rocks but not with particle sorting while the Sr isotopic composition and REE contents of residual sediments were affected by particle sorting in addition to source rocks. The onshore RSR sediments originated mainly from mixing of the fine-grained sediments from various parts of the offshore RSR in terms of REE geochemical and isotopic analyses. Isotopic and REE geochemical comparison further reveals that the RSRs off the Jiangsu Coast were fed chiefly by the dispersal of surface sediments from the Yangtze River Mouth. Surface sediments from the Yangtze River Mouth were directly dispersed to the RSRs along the Jiangsu Coast and significantly affected the seaward part of the offshore RSR and the old Yellow River Delta area by a northward branch of the Changjiang Diluted Freshwater Plume. Only minor quantities of surface sediments from the modern Yellow River Mouth were introduced into the RSRs by the Jiangsu Coastal Current and mainly contaminated the landward part of the offshore RSR area. Our findings highlighted the potential of the Nd isotopes with REE geochemistry to trace the provenance of coastal sediments. - Highlights: • Nd isotopic and REE geochemical compositions of coastal and estuary sediments are mainly associated with source rocks. • Onshore RSR sediments originate from mixing of fine-grained sediments from various parts of the offshore RSR. • The RSRs off the Jiangsu Coast

  16. Bioleaching of Zn, Ni and Fe from contaminated sediments of water reservoir Ružín I with using heterotrophic bacterial strains

    Directory of Open Access Journals (Sweden)

    Katarína Jablonovská

    2012-12-01

    Full Text Available This study investigates the bioleaching of the zinc polluted sediment from water reservoir Ružín I using heterotrophic bacterialstrains ubiquitous in sediment environment. The effect of bacterial activity, pH, iron solubilization and precipitation and bioleachingmedium were evaluated. The pH value controls the bacterial activity during the leaching process. Addition of glucose to the bioleachingmedium accelerated the bioleaching rate. The results indicates, that the leachibility of zinc depend on the geochemical formsand surface interaction between metal and sediment fraction. Sequential chemical extraction confirm, that Zn was predominantly boundto the iron-manganese oxides.

  17. Assessment of the acute toxicity of eutrophic sediments after the addition of calcium nitrate (Ibirité reservoir, Minas Gerais-SE Brazil: initial laboratory experiments

    Directory of Open Access Journals (Sweden)

    H. Janke

    Full Text Available This study evaluated the acute toxicity of sediment in a eutrophic reservoir after remediation with a calcium nitrate solution to retain phosphorus. The study involved microcosms of surface sediments and water from the sediment-water interface in the Ibirité reservoir. This reservoir, located in the vicinity of metropolitan Belo Horizonte (Minas Gerais, SE Brazil, is a water body that receives treated effluents from an oil refinery (REGAP-Petrobras, as well as high loads of untreated urban effluents from the city of Ibirité and surrounding areas and industrial effluents from a major industrial park. Incubation times of the treatment experiments were: t = 0, t = 5, t = 10, t = 25, t = 50, t = 85 and t = 135 days. One control microcosm and three treated microcosms were analysed in each time interval. Acute toxicity of water samples was assessed with Ceriodaphnia silvestrii Daday, 1902 and that of bulk sediment samples with Chironomus xanthus Rempel, 1939. Toxicity tests were carried out concomitantly with chemical analyses of dissolved inorganic nitrogen species (ammonia, nitrate and nitrite, sulfate and metals in the water samples of the microcosms. Acid volatile sulfides (AVS, simultaneously extracted metal (SEM and potentially bioavailable metal were analyzed in bulk sediment samples. Neither of the tested organisms showed toxicity in the control microcosm samples. The water column of the treated microcosm showed toxicity to C. silvestrii, starting at t = 10 days, while the sediment pore water toxicity started at t = 0 day. However, toxicity was found to decline from t = 85 days to t = 135 days. Sediments showed toxicity to C. xanthus during the entire experiment, except at the longest incubation time (t = 135 days. The overall results indicate that nitrate, which reached concentrations exceeding 1,200 mg N-NO3- L-1 in the sediment pore water of the treated microcosms, was most probably responsible for the toxicity of the samples. Although

  18. Water- and air-quality and surficial bed-sediment monitoring of the Sweetwater Reservoir watershed, San Diego County, California, 2003-09

    Science.gov (United States)

    Mendez, Gregory O.; Majewski, Michael S.; Foreman, William T.; Morita, Andrew Y.

    2015-01-01

    In 1998, the U.S. Geological Survey, in cooperation with the Sweetwater Authority, began a study to assess the overall health of the Sweetwater watershed in San Diego County, California. This study was designed to provide a data set that could be used to evaluate potential effects from the construction and operation of State Route 125 within the broader context of the water quality and air quality in the watershed. The study included regular sampling of water, air, and surficial bed sediment at Sweetwater Reservoir (SWR) for chemical constituents, including volatile organic compounds (VOCs), base-neutral and acid- extractable organic compounds (BNAs) that include polycyclic aromatic hydrocarbons (PAHs), pesticides, and metals. Additionally, water samples were collected for anthropogenic organic indicator compounds in and around SWR. Background water samples were collected at Loveland Reservoir for VOCs, BNAs, pesticides, and metals. Surficial bed-sediment samples were collected for PAHs, organochlorine pesticides, and metals at Sweetwater and Loveland Reservoirs.

  19. The presence of radioactive materials in soil, sand and sediment samples of Potenga sea beach area, Chittagong, Bangladesh: Geological characteristics and environmental implication

    Science.gov (United States)

    Yasmin, Sabina; Barua, Bijoy Sonker; Uddin Khandaker, Mayeen; Kamal, Masud; Abdur Rashid, Md.; Abdul Sani, S. F.; Ahmed, H.; Nikouravan, Bijan; Bradley, D. A.

    2018-03-01

    Accurate quantification of naturally occurring radioactive materials in soil provides information on geological characteristics, possibility of petroleum and mineral exploration, radiation hazards to the dwelling populace etc. Of practical significance, the earth surface media (soil, sand and sediment) collected from the densely populated coastal area of Chittagong city, Bangladesh were analysed using a high purity germanium γ-ray spectrometer with low background radiation environment. The mean activities of 226Ra (238U), 232Th and 40K in the studied materials show higher values than the respective world average of 33, 36 and 474 Bq/kg reported by the UNSCEAR (2000). The deduced mass concentrations of the primordial radionuclides 238U, 232Th and 40K in the investigated samples are corresponding to the granite rocks, crustal minerals and typical rocks respectively. The estimated mean value of 232Th/238U for soil (3.98) and sediment (3.94) are in-line with the continental crustal average concentration of 3.82 for typical rock range reported by the National Council on Radiation Protection and Measurements (NCRP). But the tonalites and more silicic rocks elevate the mean value of 232Th/238U for sand samples amounting to 4.69. This indicates a significant fractionation during weathering or associated with the metasomatic activity in the investigated area of sand collection.

  20. Modeling the source contribution of heavy metals in surficial sediment and analysis of their historical changes in the vertical sediments of a drinking water reservoir

    Science.gov (United States)

    Wang, Guoqiang; A, Yinglan; Jiang, Hong; Fu, Qing; Zheng, Binghui

    2015-01-01

    Increasing water pollution in developing countries poses a significant threat to environmental health and human welfare. Understanding the spatial distribution and apportioning the sources of pollution are important for the efficient management of water resources. In this study, ten types of heavy metals were detected during 2010-2013 for all ambient samples and point sources samples. A pollution assessment based on the surficial sediment dataset by Enrichment Factor (EF) showed the surficial sediment was moderately contaminated. A comparison of the multivariate approach (principle components analysis/absolute principle component score, PCA/APCS) and the chemical mass balance model (CMB) shows that the identification of sources and calculation of source contribution based on the CMB were more objective and acceptable when source profiles were known and source composition was complex. The results of source apportionment for surficial heavy metals, both from PCA/APCS and CMB model, showed that the natural background (30%) was the most dominant contributor to the surficial heavy metals, followed by mining activities (29%). The contribution percentage of the natural background was negatively related to the degree of contamination. The peak concentrations of many heavy metals (Cu, Ba, Fe, As and Hg) were found in the middle layer of sediment, which is most likely due to the result of development of industry beginning in the 1970s. However, the highest concentration of Pb appeared in the surficial sediment layer, which was most likely due to the sharp increase in the traffic volume. The historical analysis of the sources based on the CMB showed that mining and the chemical industry are stable sources for all of the sections. The comparing of change rates of source contribution versus years indicated that the composition of the materials in estuary site (HF1) is sensitive to the input from the land, whereas center site (HF4) has a buffering effect on the materials from

  1. Benthic metal fluxes and sediment diagenesis in a water reservoir affected by acid mine drainage: A laboratory experiment and reactive transport modeling

    Science.gov (United States)

    Torres, E.; Ayora, C.; Jiménez-Arias, J. L.; García-Robledo, E.; Papaspyrou, S.; Corzo, A.

    2014-08-01

    Reservoirs are one of the primary water supply sources. Knowledge of the metal fluxes at the water-sediment interfaces of reservoirs is essential for predicting their ecological quality. Redox oscillations in the water column are promoted by stratification; turnover events may significantly alter metal cycling, especially in reservoirs impacted by acid mine drainage (AMD). To study this phenomenon, an experiment was performed under controlled laboratory conditions. Sediment cores from an AMD-affected reservoir were maintained in a tank with reservoir water for approximately two months and subjected to alternating oxic-hypoxic conditions. A detailed metal speciation in solid phases of the sediment was initially performed by sequential extraction, and pore water was analyzed at the end of each redox period. Tank water metals concentrations were systematically monitored throughout the experiment. The experimental results were then used to calibrate a diffusion-reaction model and quantify the reaction rates and sediment-water fluxes. Under oxic conditions, pH, Fe and As concentrations decreased in the tank due to schwertmannite precipitation, whereas the concentrations of Al, Zn, Cu, Ni, and Co increased due to Al(OH)3 and sulfide dissolution. The reverse trends occurred under hypoxic conditions. Under oxic conditions, the fluxes calculated by applying Fick’s first law to experimental concentration gradients contradicted the fluxes expected based on the evolution of the tank water. According to the reactive transport calculations, this discrepancy can be attributed to the coarse resolution of sediment sampling. The one-cm-thick slices failed to capture effectively the notably narrow (1-2 mm) concentration peaks of several elements in the shallow pore water resulting from sulfide and Al(OH)3 dissolution. The diffusion-reaction model, extended to the complete year, computed that between 25% and 50% of the trace metals and less than 10% of the Al that precipitated under

  2. Reconstructing depositional processes and history from reservoir stratigraphy: Englebright Lake, Yuba River, northern California

    Science.gov (United States)

    Snyder, N.P.; Wright, S.A.; Alpers, Charles N.; Flint, L.E.; Holmes, C.W.; Rubin, D.M.

    2006-01-01

    Reservoirs provide the opportunity to link watershed history with its stratigraphic record. We analyze sediment cores from a northern California reservoir in the context of hydrologic history, watershed management, and depositional processes. Observations of recent depositional patterns, sediment-transport calculations, and 137CS geochronology support a conceptual model in which the reservoir delta progrades during floods of short duration (days) and is modified during prolonged (weeks to months) drawdowns that rework topset beds and transport sand from topsets to foresets. Sediment coarser than 0.25-0.5 mm. deposits in foresets and topsets, and finer material falls out of suspension as bottomset beds. Simple hydraulic calculations indicate that fine sand (0.063-0.5 mm) is transported into the distal bottomset area only during floods. The overall stratigraphy suggests that two phases of delta building occurred in the reservoir. The first, from dam construction in 1940 to 1970, was heavily influenced by annual, prolonged >20 m drawdowns of the water level. The second, built on top of the first, reflects sedimentation from 1970 to 2002 when the influence of drawdowns was less. Sedimentation rates in the central part of the reservoir have declined ???25% since 1970, likely reflecting a combination of fewer large floods, changes in watershed management, and winnowing of stored hydraulic mining sediment. Copyright 2006 by the American Geophysical Union.

  3. Clay minerals in sediments of Portuguese reservoirs and their significance as weathering products from over-eroded soils: a comparative study of the Maranhão, Monte Novo and Divor Reservoirs (South Portugal)

    Science.gov (United States)

    Fonseca, Rita M. F.; Barriga, Fernando J. A. S.; Conceição, Patrícia I. S. T.

    2010-12-01

    The Southern region of Portugal is subjected to several forms of over-erosion. Most leached products, mainly composed of fine particles containing nutrients, metals or pesticides, are easily transported by river flows. When these are hindered by a physical barrier such as a dam, the particulate load accumulates on the bottom of the reservoirs, often leading to a pronounced decrease of water quality. Bottom sediments from three reservoirs were subjected to grain-size analysis and a study of clay minerals by X-ray diffraction. Most sediments contain a diverse set of clay minerals, mostly illites, smectites, chlorites and kaolinites. The nature of the clay minerals reflects the nature of the parent rocks. During the cycles of transport and temporary deposition, they may undergo significant chemical and physical transformations, which lead to an increase of expandable properties and therefore, to a higher cationic exchange capacity, determining its important role as vehicles of environmental pollutants.

  4. 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.

  5. Longitudinal variability of phosphorus fractions in sediments of a canyon reservoir due to cascade dam construction: a case study in Lancang River, China.

    Directory of Open Access Journals (Sweden)

    Qi Liu

    Full Text Available Dam construction causes the accumulation of phosphorus in the sediments of reservoirs and increases the release rate of internal phosphorus (P loading. This study investigated the longitudinal variability of phosphorus fractions in sediments and the relationship between the contents of phosphorus fractions and its influencing factors of the Manwan Reservoir, Lancang River, Yunnan Province, China. Five sedimentary phosphorus fractions were quantified separately: loosely bound P (ex-P; reductant soluble P (BD-P; metal oxide-bound P (NaOH-P; calcium-bound P (HCl-P, and residual-P. The results showed that the total phosphorus contents ranged from 623 to 899 µg/g and were correlated positively with iron content in the sediments of the reservoir. The rank order of P fractions in sediments of the mainstream was HCl-P>NaOH-P>residual-P>BD-P>ex-P, while it was residual-P>HCl-P>NaOH-P>BD-P>ex-P in those of the tributaries. The contents of bio-available phosphorus in the tributaries, including ex-P, BD-P and NaOH-P, were significantly lower than those in the mainstream. The contents of ex-P, BD-P, NaOH-P showed a similar increasing trend from the tail to the head of the Manwan Reservoir, which contributed to the relatively higher content of bio-available phosphorus, and represents a high bio-available phosphorus releasing risk within a distance of 10 km from Manwan Dam. Correlation and redundancy analyses showed that distance to Manwan Dam and the silt/clay fraction of sediments were related closely to the spatial variation of bio-available phosphorus.

  6. Determination of total and organic mercury and evaluation of methylation and demethylation processes in sediments of the Rio Grande Reservoir, State of Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Franklin, Robson Leocadio

    2010-01-01

    The Rio Grande reservoir is located in the metropolitan area of Sao Paulo and it is a very important water supply for this region. In the present study bottom waters and sediment samples collected in this reservoir, in four sampling points, in four campaigns, from September 2008 to January 2010, were analyzed. Firstly total Hg was determined in sediment and bottom waters by cold vapor atomic absorption technique (CV AAS). Following, the analytical methodology for organic Hg was adapted from literature, where the organomercurial compounds were extracted with dichloromethane in acid medium and subsequent destruction of organic compounds by bromine chloride. The validation of this methodology, in terms of precision and accuracy, was performed by means of IAEA 405 and BCR-CRM 580 reference materials analyses. For methylation and demethylation processes evaluation in this environment, the following physical and chemical parameters were assessed, in situ: pH, water temperature, redox potential (EH), transparency and depth. For the sediment samples, granulometry, total organic carbon, sulphate-reducing bacteria, total N and P, besides the metals Co, Cu, Fe and Mn were evaluated. The selection of these parameters was related to the factors that influence the behavior of MeHg in the sediments and its transition zone. Total Hg ranging from 1.0 to 71.0 mg kg'- 1 and organic mercury from -1 in sediments and methylation rates from 0.06 to 1.4% were found, along the reservoir. Different methylation conditions along the reservoir and its influences were also discussed. As supplementary study the concentration of some metals and trace elements in the sediments by neutron activation analysis technique was determined. As, Ba, Br, Co, Cr, Cs, Hf, Fe, Na, Rb, Sb, Sc and Zn and rare earth elements Ce, Eu, La, Lu, Nd, Sm and Yb were determined. The enrichment factor in relation to earth crust values using Sc as normalizer element reached values higher than 2.0 for the elements As, Br

  7. Post-depositional redistribution of trace metals in reservoir sediments of a mining/smelting-impacted watershed (the Lot River, SW France)

    International Nuclear Information System (INIS)

    Audry, Stephane; Grosbois, Cecile; Bril, Hubert; Schaefer, Joerg; Kierczak, Jakub; Blanc, Gerard

    2010-01-01

    Mining/smelting wastes and reservoir sediment cores from the Lot River watershed were studied using mineralogical (XRD, SEM-EDS, EMPA) and geochemical (redox dynamics, selective extractions) approaches to characterize the main carrier phases of trace metals. These two approaches permitted determining the role of post-depositional redistribution processes in sediments and their effects on the fate and mobility of trace metals. The mining/smelting wastes showed heterogeneous mineral compositions with highly variable contents of trace metals. The main trace metal-bearing phases include spinels affected by secondary processes, silicates and sulfates. The results indicate a clear change in the chemical partitioning of trace metals between the reservoir sediments upstream and downstream of the mining/smelting activities, with the downstream sediments showing a 2-fold to 5-fold greater contribution of the oxidizable fraction. This increase was ascribed to stronger post-depositional redistribution of trace metals related to intense early diagenetic processes, including dissolution of trace metal-bearing phases and precipitation of authigenic sulfide phases through organic matter (OM) mineralization. This redistribution is due to high inputs (derived from mining/smelting waste weathering) at the water-sediment interface of (i) dissolved SO 4 promoting more efficient OM mineralization, and (ii) highly reactive trace metal-bearing particles. As a result, the main trace metal-bearing phases in the downstream sediments are represented by Zn- and Fe-sulfides, with minor occurrence of detrital zincian spinels, sulfates and Fe-oxyhydroxides. Sequestration of trace metals in sulfides at depth in reservoir sediments does not represent long term sequestration owing to possible resuspension of anoxic sediments by natural (floods) and/or anthropogenic (dredging, dam flush) events that might promote trace metal mobilization through sulfide oxidation. It is estimated that, during a major

  8. Can we predict the response of large sand bed rivers to changes in flow and sediment supply? The case of the Missouri River.

    Science.gov (United States)

    Viparelli, E.; Blum, M. D.

    2015-12-01

    In the past century engineering projects and changes in land use significantly modified the hydrology and the sediment supply of large sand bed rivers all over the world. Field studies documented the river responses to the imposed changes, which can be summarized as adjustments in channel geometry, slope, and/or characteristics of the bed material. Further, one-, two- and three-dimensional river morphodynamic models were used to predict the fluvial system response to the imposed changes at time scales ranging from few months up to several decades. Notwithstading this previous research effort, the spatial and temporal scales of river adjustment, as well as quantitative predictions of the river responses, are still a matter of debate due to the difficulties associated with the interpretation of limited field datasets and with the large scale sediment transport modeling. Here we present the preliminary results of a study of the Missouri River response to the construction of dams, i.e. reduction in flood flow and sediment supply. In particular, we first compare the numerical results of a one-dimensional model of river morphodynamics for large, low slope sand bed rivers with field data to validate the model. The validated model is then used to constrain the spatial and temporal scales of the river adjustment, i.e. bed degradation in the Missouri River case. In other words, our numerical work focuses on how the magnitude and speed of the wave of channel bed degradation changes in time and space for the Missouri River case and how these scales change for different values of the ratio between pre- and pos-dam flow rates, and pre- and post-dam sediment loads.

  9. Mass Transfer Behavior of Perfluorinated Chemicals in Saturated Clay-rich Sands: A Laboratory-based Study on Fate and Transport in Groundwater and Sediments

    Science.gov (United States)

    Greenberg, R. R.; Tick, G. R.; Abbott, J. B., III; Carroll, K. C.

    2017-12-01

    Perfluoroalkyl substances (PFAS) are a class of emerging contaminants that pose a threat to the human health and the quality of groundwater, surface water, and drinking water supplies. This study aims to elucidate the primary physicochemical factors controlling the fate and transport of the PFAS contaminants, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), in groundwater. Physicochemical processes of intercalation, adsorption, and desorption were investigated for the retention of PFAS at different initial aqueous-phase concentrations in modified-natural sediments composed of sand (40/50 accusand; foc = 0.04% unmodified) with low, medium, and high organic carbon contents (foc = 10, 20, and 50%) and various pre-conditioned clay-fractions. Diffusional mass-transfer limitations were evaluated based on initial PFAS concentration, specific clay structure, and resulting contaminant intercalation (d-spacing changes). A series of short- (48 hr), medium- (7 day) and long-term (30 day) batch and column experiments were conducted to determine physicochemical processes as a function of compound chemistry, sediment geochemistry, sorbent crystalline structure, and contaminant/sediment contact-time. Physicochemical parameters, PFAS concentrations, and sediment characterization were conducted using high performance liquid chromatography (HPLC), X-ray diffraction (XRD), and furnace combustion analytical techniques. The results of PFAS contaminant transport, under the different conditions tested, provide a scientific contribution with application to the development of improved risk assessments, predictions of fate and transport, and more effective remediation strategies for emerging perfluorinated contaminants in soil and groundwater.

  10. Aggregated Transfer Factors For Small Mammals Collected From the Exposed Sediments Of A 137 Cs Contaminated Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Paller, Michael H.; Jannika, G. Timothy; Wike, Lynn D

    2005-10-04

    {sup 137}Cs transfer factors were computed for small mammals collected from the dried sediment areas of a partially drained, contaminated reservoir. Soil {sup 137}Cs concentrations were heterogeneous on small and large spatial scales, with a geometric mean of 253.1 Bq/kg dry weight. About 50% of the variance in cotton rat Sigmodon hispidus tissue {sup 137}Cs levels was explained by variation in soil {sup 137}Cs levels. Soil to animal transfer factors (whole body dry weight) averaged 6.0 for cotton rats and 1.2 for cotton mice Peromyscus gossypinus. These values are similar to {sup 137}Cs transfer factors for herbivorous, homeothermic animals from other contaminated ecosystems. Site-specific transfer factors can significantly affect the estimation of dose. In the RESRAD-BIOTA dose model, the default transfer factor for {sup 137}Cs in terrestrial animals is 110 resulting in an estimate of radiation dose to terrestrial biota that is 16 times more than the dose calculated with the actual measured transfer factor.

  11. Application of the Taguchi Method for Optimizing the Process Parameters of Producing Lightweight Aggregates by Incorporating Tile Grinding Sludge with Reservoir Sediments.

    Science.gov (United States)

    Chen, How-Ji; Chang, Sheng-Nan; Tang, Chao-Wei

    2017-11-10

    This study aimed to apply the Taguchi optimization technique to determine the process conditions for producing synthetic lightweight aggregate (LWA) by incorporating tile grinding sludge powder with reservoir sediments. An orthogonal array L 16 (4⁵) was adopted, which consisted of five controllable four-level factors (i.e., sludge content, preheat temperature, preheat time, sintering temperature, and sintering time). Moreover, the analysis of variance method was used to explore the effects of the experimental factors on the particle density, water absorption, bloating ratio, and loss on ignition of the produced LWA. Overall, the produced aggregates had particle densities ranging from 0.43 to 2.1 g/cm³ and water absorption ranging from 0.6% to 13.4%. These values are comparable to the requirements for ordinary and high-performance LWAs. The results indicated that it is considerably feasible to produce high-performance LWA by incorporating tile grinding sludge with reservoir sediments.

  12. Drawdown flushing of a hydroelectric reservoir on the Rhône River: Impacts on the fish community and implications for the sediment management.

    Science.gov (United States)

    Grimardias, David; Guillard, Jean; Cattanéo, Franck

    2017-07-15

    Sediment flushings of hydropower reservoirs are commonly performed to maintain water resource uses and ecosystem services, but may have strong impacts on fish communities. Despite the worldwide scope of this issue, very few studies report quantitative in situ evaluations of these impacts. In June 2012, the drawdown flushing of the Verbois reservoir (Rhône River) was performed and subsequent impacts on the fish community were assessed, both inside the reservoir (fish densities by hydroacoustic surveys) and downstream (short-term movement and survival of radio tracked adult fish). Results showed that after the flushing fish acoustic density decreased by 57% in the reservoir, and no recolonization process was observed over the following 16 months. Downstream of the dam, the global apparent survival of fish to the flushing was estimated at 74%, but differed between species. The nine-year delay from the previous flushing and thus the amount of sediments to remove were too stressful for the low-resilience fish community of the Rhône River. Alternative flushing schedules are discussed to reduce these impacts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Sedimentology and preservation of aeolian sediments on steep terrains : Incipient sand ramps on the Atacama coast (northern Chile)

    NARCIS (Netherlands)

    Ventra, Dario; Rodríguez-López, Juan Pedro; de Boer, Poppe L.

    2017-01-01

    The origin of topographically controlled aeolian landforms in high-relief settings is difficult to synthesize under general models, given the dependence of such accumulations on local morphology. Quaternary sand ramps have been linked to palaeoclimate, regional geomorphology and wind patterns;

  14. Using Sieving and Unknown Sand Samples for a Sedimentation-Stratigraphy Class Project with Linkage to Introductory Courses

    Science.gov (United States)

    Videtich, Patricia E.; Neal, William J.

    2012-01-01

    Using sieving and sample "unknowns" for instructional grain-size analysis and interpretation of sands in undergraduate sedimentology courses has advantages over other techniques. Students (1) learn to calculate and use statistics; (2) visually observe differences in the grain-size fractions, thereby developing a sense of specific size…

  15. Water level fluctuations in a tropical reservoir: the impact of sediment drying, aquatic macrophyte dieback, and oxygen availability on phosphorus mobilization.

    Science.gov (United States)

    Keitel, Jonas; Zak, Dominik; Hupfer, Michael

    2016-04-01

    Reservoirs in semi-arid areas are subject to water level fluctuations (WLF) that alter biogeochemical processes in the sediment. We hypothesized that wet-dry cycles may cause internal eutrophication in such systems when they affect densely vegetated shallow areas. To assess the impact of WLF on phosphorus (P) mobilization and benthic P cycling of iron-rich sediments, we tested the effects of (i) sediment drying and rewetting, (ii) the impact of organic matter availability in the form of dried Brazilian Waterweed (Egeria densa), and (iii) alternating redox conditions in the surface water. In principle, drying led to increased P release after rewetting both in plant-free and in plant-amended sediments. Highest P mobilization was recorded in plant amendments under oxygen-free conditions. After re-establishment of aerobic conditions, P concentrations in surface water decreased substantially owing to P retention by sediments. In desiccated and re-inundated sediments, P retention decreased by up to 30% compared to constantly inundated sediments. We showed that WLF may trigger biochemical interactions conducive to anaerobic P release. Thereby, E. densa showed high P release and even P uptake that was redox-controlled and superimposed sedimentary P cycling. Macrophytes play an important role in the uptake of P from the water but may be also a significant source of P in wet-dry cycles. We estimated a potential for the abrupt release of soluble reactive phosphorus (SRP) by E. densa of 0.09-0.13 g SRP per m(2) after each wet-dry cycle. Released SRP may exceed critical P limits for eutrophication, provoking usage restrictions. Our results have implications for management of reservoirs in semi-arid regions affected by WLF.

  16. Flux of nitrogen, phosphorus, and suspended sediment from the Susquehanna River Basin to the Chesapeake Bay during Tropical Storm Lee, September 2011, as an indicator of the effects of reservoir sedimentation on water quality

    Science.gov (United States)

    Hirsch, Robert M.

    2012-01-01

    Concentrations of nitrogen, phosphorus, and suspended sediment are measured at the U.S. Geological Survey streamgage at Conowingo Dam at the downstream end of the Susquehanna River Basin in Maryland, where the river flows into the Chesapeake Bay. During the period September 7-15, 2011, in the aftermath of Tropical Storm Lee, concentrations of these three constituents were among the highest ever measured at this site. These measurements indicate that sediment-storage processes behind the three dams on the lower Susquehanna River are evolving. In particular, they indicate that scouring of sediment (and the nitrogen and phosphorus attached to that sediment) may be increasing with time. Trends in flow-normalized fluxes at the Susquehanna River at Conowingo, Maryland, streamgage during 1996-2011 indicate a 3.2-percent decrease in total nitrogen, but a 55-percent increase in total phosphorus and a 97-percent increase in suspended sediment. These large increases in the flux of phosphorus and sediment from the Susquehanna River to the Chesapeake Bay have occurred despite reductions in the fluxes of these constituents from the Susquehanna River watershed upstream from the reservoirs. Although the Tropical Storm Lee flood event contributed about 1.8 percent of the total streamflow from the Susquehanna River to the Chesapeake Bay over the past decade (water years 2002-11), it contributed about 5 percent of the nitrogen, 22 percent of the phosphorus, and 39 percent of the suspended sediment during the same period. These results highlight the importance of brief high-flow events in releasing nitrogen, phosphorus, and sediment derived from the Susquehanna River watershed and stored in the Conowingo Reservoir to the Chesapeake Bay.

  17. Strength Estimation for Hydrate-Bearing Sediments From Direct Shear Tests of Hydrate-Bearing Sand and Silt

    Science.gov (United States)

    Liu, Zhichao; Dai, Sheng; Ning, Fulong; Peng, Li; Wei, Houzhen; Wei, Changfu

    2018-01-01

    Safe and economic methane gas production, as well as the replacement of methane while sequestering carbon in natural hydrate deposits, requires enhanced geomechanical understanding of the strength and volume responses of hydrate-bearing sediments during shear. This study employs a custom-made apparatus to investigate the mechanical and volumetric behaviors of carbon dioxide hydrate-bearing sediments subjected to direct shear. The results show that both peak and residual strengths increase with increased hydrate saturation and vertical stress. Hydrate contributes mainly the cohesion and dilatancy constraint to the peak strength of hydrate-bearing sediments. The postpeak strength reduction is more evident and brittle in specimens with higher hydrate saturation and under lower stress. Significant strength reduction after shear failure is expected in silty sediments with high hydrate saturation Sh ≥ 0.65. Hydrate contribution to the residual strength is mainly by increasing cohesion at low hydrate saturation and friction at high hydrate saturation. Stress state and hydrate saturation are dominating both the stiffness and the strength of hydrate-bearing sediments; thus, a wave velocity-based peak strength prediction model is proposed and validated, which allows for precise estimation of the shear strength of hydrate-bearing sediments through acoustic logging data. This method is advantageous to geomechanical simulators, particularly when the experimental strength data of natural samples are not available.

  18. Use of reservoir deposits to reconstruct the recent changes in sediment yields from a small granite catchment in the Yimeng Mountain region, China

    Science.gov (United States)

    Zhang, Yunqi; Long, Yi; Li, Bao; Xu, Shujian; Wang, Xiaoli; Liao, Jia

    2017-09-01

    Information on recent changes in sediment yields from small catchments provides a better understanding of temporal trends in soil loss from certain physical and human-influenced landscapes that have been subjected to recent environmental changes, and will help bridge the current knowledge gap that exists between hillslope erosion and sediment transport in rivers. The Yimeng Mountain region, characterized by alternating granite and limestone, is one of the most susceptible regions to soil erosion in northern China, and has been subjected to intensive anthropogenic activity in recent years. Soil loss from areas underlain by granite is particularly obvious, and is the main sediment source for the Yihe River. In this study, we used reservoir deposits to estimate the changes in sediment yields over the past 50 years from a small catchment underlain by granite, namely the Jiangzhuang catchment in the Yimeng Mountain region. Three cores were collected from the Jiangzhuang Reservoir in the catchment. The activities of 137Cs and 210Pbex at different depths, clay (grain size reference to human activity and environmental change in the catchment. The chronologies of the cores were established by 137Cs and 210Pbex dating. The area-specific sediment yield (SSY) for different time periods since dam construction was estimated from each core by referring to the original capacity curve of the reservoir. The results indicate that the depth profiles of 137Cs, 210Pbex, clay, and SOC contents in cores from the Jiangzhuang Reservoir reflect the general history of human disturbances on the catchment over the past 50 years. The estimated SSY value from each core for each period ranged from 7.2 ± 2.7 to 23.7 ± 8.3 t ha- 1 y- 1, with a mean of 12.5 ± 4.6 t ha- 1 y- 1. SSY decreased during 1954-1972, and then showed a general tendency to increase. The temporal pattern of the sediment yield largely reflects the history of environmental change influenced by human activity in the catchment.

  19. Riverbed Sediments as Reservoirs of Multiple Vibrio cholerae Virulence-Associated Genes: A Potential Trigger for Cholera Outbreaks in Developing Countries.

    Science.gov (United States)

    Abia, Akebe Luther King; Ubomba-Jaswa, Eunice; Momba, Maggy Ndombo Benteke

    2017-01-01

    Africa remains the most cholera stricken continent in the world as many people lacking access to safe drinking water rely mostly on polluted rivers as their main water sources. However, studies in these countries investigating the presence of Vibrio cholerae in aquatic environments have paid little attention to bed sediments. Also, information on the presence of virulence-associated genes (VAGs) in environmental ctx -negative V. cholerae strains in this region is lacking. Thus, we investigated the presence of V. cholerae VAGs in water and riverbed sediment of the Apies River, South Africa. Altogether, 120 samples (60 water and 60 sediment samples) collected from ten sites on the river (January and February 2014) were analysed using PCR. Of the 120 samples, 37 sediment and 31 water samples were positive for at least one of the genes investigated. The haemolysin gene (hlyA) was the most isolated gene. The cholera toxin (ctxAB) and non-O1 heat-stable (stn/sto) genes were not detected. Genes were frequently detected at sites influenced by human activities. Thus, identification of V. cholerae VAGs in sediments suggests the possible presence of V. cholerae and identifies sediments of the Apies River as a reservoir for potentially pathogenic V. cholerae with possible public health implications.

  20. Riverbed Sediments as Reservoirs of Multiple Vibrio cholerae Virulence-Associated Genes: A Potential Trigger for Cholera Outbreaks in Developing Countries

    Directory of Open Access Journals (Sweden)

    Akebe Luther King Abia

    2017-01-01

    Full Text Available Africa remains the most cholera stricken continent in the world as many people lacking access to safe drinking water rely mostly on polluted rivers as their main water sources. However, studies in these countries investigating the presence of Vibrio cholerae in aquatic environments have paid little attention to bed sediments. Also, information on the presence of virulence-associated genes (VAGs in environmental ctx-negative V. cholerae strains in this region is lacking. Thus, we investigated the presence of V. cholerae VAGs in water and riverbed sediment of the Apies River, South Africa. Altogether, 120 samples (60 water and 60 sediment samples collected from ten sites on the river (January and February 2014 were analysed using PCR. Of the 120 samples, 37 sediment and 31 water samples were positive for at least one of the genes investigated. The haemolysin gene (hlyA was the most isolated gene. The cholera toxin (ctxAB and non-O1 heat-stable (stn/sto genes were not detected. Genes were frequently detected at sites influenced by human activities. Thus, identification of V. cholerae VAGs in sediments suggests the possible presence of V. cholerae and identifies sediments of the Apies River as a reservoir for potentially pathogenic V. cholerae with possible public health implications.

  1. Sedimentological and Scanning Electron Miscroscopic Descriptions of Afowo Oil Sand Deposits, South Western Nigeria

    Directory of Open Access Journals (Sweden)

    Akinmosin A

    2017-12-01

    Full Text Available Sedimentological and scanning electron microscopic analyses of some shallow reservoir tar sand samples in parts of Southwestern Nigeria were carried out with the aim of characterizing the reservoir properties in relation to bitumen saturation and recovery efficiency. The production of impregnated tar from the sands requires the reservoir to be of good quality. A total of thirty samples were collected at different localities within the tar sand belt (ten out of these samples were selected for various reservoir quality analyses based on their textural homogeneity. The result of particle size distribution study showed that bulk of the sands is medium – coarse grained and moderately sorted. The grain morphologies are of low to high sphericity with shapes generally sub-angular to sub-rounded, implying that the sands have undergone a fairly long transportation history with depositional energy having a moderate to high velocity. The quartz content was made up of about 96% of the total mineralogical components; the sediments of the Afowo Formation can be described to be mineralogically and texturally stable. The result of the scanning electron microscopy (SEM analysis revealed that the oil sands contained minerals which had been precipitated and occurred as pore filling cement; these minerals include sheet kaolinite, block kaolinite, vermiform kaolinite, pyrite crystals and quartz. The SEM images also showed micro-pores ranging from 0.057µm to 0.446µm and fractures. The study showed that the clay minerals contained in the Afowo reservoir rocks were mainly kaolinite. Kaoline unlike some other clays (e.g Montimorillonite does not swell with water, hence it is not expected to have any negative effects on the reservoir quality, especially during enhanced oil recovery operations.

  2. Modeling the Effects of Reservoir Releases on the Bed Material Sediment Flux of the Colorado River in western Colorado and eastern Utah

    Science.gov (United States)

    Pitlick, J.; Bizzi, S.; Schmitt, R. J. P.

    2017-12-01

    Warm-water reaches of the upper Colorado River have historically provided important habitat for four endangered fishes. Over time these habitats have been altered or lost due to reductions in peak flows and sediment loads caused by reservoir operations. In an effort to reverse these trends, controlled reservoir releases are now used to enhance sediment transport and restore channel complexity. In this presentation, we discuss the development of a sediment routing model designed to assess how changes in water and sediment supply can affect the mass balance of sediment. The model is formulated for ten reaches of the Colorado River spanning 250 km where values of bankfull discharge, width, and reach-average slope have been measured. Bed surface grain size distributions (GSDs) have also been measured throughout the study area; these distributions are used as a test of the model, not as input, except as an upstream boundary condition. In modeling fluxes and GSDs, we assume that the bed load transport capacity is determined by local hydraulic conditions and bed surface grain sizes. Estimates of the bankfull bed load transport capacity in each reach are computed for 14 size fractions of the surface bed material, and the fractional transport rates are summed to get the total transport capacity. In the adjacent reach, fluxes of each size fraction from upstream are used to determine the mean grain size, and the fractional transport capacity of that reach. Calculations proceed downstream and illustrate how linked changes in discharge, shear stress and mean grain size affect (1) the total bed load transport capacity, and (2) the size distribution of the bed surface sediment. The results show that model-derived GSDs match measured GSDs very closely, except for two reaches in the lower part of the study area where slope is affected by uplift associated with salt diapirs; here the model significantly overestimates the transport capacity in relation to the supply. Except for these

  3. Sedimentation studies at MUDA catchment area, Kedah, Malaysia

    International Nuclear Information System (INIS)

    Kamarudin Samuding; Juhari Yusuf; Wan Abdul Aziz; Juhari Latiff

    2000-01-01

    A study on the sediment size distribution and determination of sediment density profile in the selected area of Muda dam catchment area, Kedah is presented. The objective of the study was to establish a base line data of the input sedimentation with regards to the effects of development within the catchment in the future. Three main sampling locations were identified namely at Sungai Teliang, Sungai Muda and Muda reservoir. Measurement of sediment thickness was performed by using nuclear gauges i.e. direct transmission and backscattering methods. Results showed that the grain size distribution of sediment ranges from gravel to clay sizes. In the reservoir and downstream of the river, most of the samples studied consisting of fine sediment i.e silt and clay sizes (<63,um). However, sediment distribution in the upstream section of Sungai Teliang mainly consist of fine to coarse sand. Sediment density profiles in the reservoir showed little changes, whereas bed sediment profiles in the river cross-sectional areas exhibit some changes. The results also showed that thickness of bedload sediment were different from one location to another, in which the thickness may achieve up to 0.75 metre in some areas. Based on the sediment distribution profile analysis, the study site could be divided into two parts comprising of dynamic area (region) covering selected locations along the river and deposited sediment in the reservoir. Basic information derived from this study may provide as one of the important inputs for the MADA reservoir management authority in monitoring, supervising y and identifying rate and source of sediment in the catchment area

  4. Assessment of pathogenic bacteria in water and sediment from a water reservoir under tropical conditions (Lake Ma Vallée), Kinshasa Democratic Republic of Congo.

    Science.gov (United States)

    Mwanamoki, Paola M; Devarajan, Naresh; Thevenon, Florian; Atibu, Emmanuel K; Tshibanda, Joseph B; Ngelinkoto, Patience; Mpiana, Pius T; Prabakar, Kandasamy; Mubedi, Josué I; Kabele, Christophe G; Wildi, Walter; Poté, John

    2014-10-01

    This study was conducted to assess potential human health risks presented by pathogenic bacteria in a protected multi-use lake-reservoir (Lake Ma Vallée) located in west of Kinshasa, Democratic Republic of Congo (DRC). Water and surface sediments from several points of the Lake were collected during summer. Microbial analysis was performed for Escherichia coli, Enterococcus (ENT), Pseudomonas species and heterotrophic plate counts. PCR amplification was performed for the confirmation of E. coli, ENT, Pseudomonas spp. and Pseudomonas aeruginosa isolated from samples. The results reveal low concentration of bacteria in water column of the lake, the bacterial quantification results observed in this study for the water column were below the recommended limits, according to WHO and the European Directive 2006/7/CE, for bathing water. However, high concentration of bacteria was observed in the sediment samples; the values of 2.65 × 10(3), 6.35 × 10(3), 3.27 × 10(3) and 3.60 × 10(8) CFU g(-1) of dry sediment for E. coli, ENT, Pseudomonas spp. and heterotrophic plate counts, respectively. The results of this study indicate that sediments of the Lake Ma Vallée can constitute a reservoir of pathogenic microorganisms which can persist in the lake. Possible resuspension of faecal indicator bacteria and pathogens would affect water quality and may increase health risks to the population during recreational activities. Our results indicate that the microbial sediment analysis provides complementary and important information for assessing sanitary quality of surface water under tropical conditions.

  5. Short-term impact of deep sand extraction and ecosystem-based landscaping on macrozoobenthos and sediment characteristics

    NARCIS (Netherlands)

    de Jong, Maarten F.; Baptist, Martin J.; Lindeboom, Han J.; Hoekstra, Piet

    2015-01-01

    We studied short-term changes in macrozoobenthos in a 20. m deep borrow pit. A boxcorer was used to sample macrobenthic infauna and a bottom sledge was used to sample macrobenthic epifauna. Sediment characteristics were determined from the boxcore samples, bed shear stress and near-bed salinity were

  6. [Fractions and adsorption characteristics of phosphorus on sediments and soils in water level fluctuating zone of the Pengxi River, a tributary of the Three Gorges Reservoir].

    Science.gov (United States)

    Sun, Wen-Bin; Du, Bin; Zhao, Xiu-Lan; He, Bing-Hui

    2013-03-01

    The sediment, one of the key factors leading to the eutrophication of water bodies, is an important ecological component of natural water body. In order to investigate the morphological characteristics and moving-transiting rule of phosphorus in the sediments of the Pengxi River, a tributary of the Three Gorges Reservoir, the distributions of different phosphorus forms on the three cross-section in the sediments and three soil types of riparian zone were investigated using the sequential extraction method. The characteristics of phosphorus adsorption on the sediments were also investigated by batch experiments. The equilibrium phosphorus concentrations at zero adsorption (EPC0) on those sediments were estimated using the Henry linear models. The results show that the total phosphorus (TP) contents of these sediments and soils of riparian zone were 0.80-1.45 g x kg(-1) and 0.65-1.16 g x kg(-1), respectively. Phosphorus in sediments and soils were divided into inorganic phosphorus (IP) and organic phosphorus (Or-P), and the inorganic phosphorus was the dominant component of TP. Of the inorganic phosphorus fractions, the percentages of phosphorus bounded to calcium (Ca-P) and occluded phosphorus (O-P) from sediments were higher than 80%, implying that the contents of phosphorus were mainly influenced by their bedrocks and the sedimentary environmental conditions, not by the activities of human beings. The fractions of Ca-P and O-P were the dominant components of inorganic phosphorus in alluvial soil and purple soil, while the fraction of O-P was the highest in the paddy soil. The EPC0 values of the sediments from the sections of Huangshi, Shuangjiang and Gaoyang were 0.08, 0.13 and 0.11 mg x L(-1) respectively, but the EPC0 values of the alluvial soil, purple soil and paddy soil located in riparian zone were 0.08, 0.09 and 0.04 mg x L(-1), respectively. Correlation analysis shows that the values of EPC0 positively related to the contents of total phosphorus and clay

  7. Syn-tectonic emplacement of deep-marine reservoir sands at rifting margins : Including a case study from the Vøring Basin

    NARCIS (Netherlands)

    Athmer, W.

    2010-01-01

    This study focuses on the interplay between large-scale relay ramps and sedimentladen flows, specifically low-density turbidity currents that form one end-member of subaqueous sediment gravity flows. The main objective is to better understand the impact of syn-rift faulting on subaqueous sediment

  8. KONTAMINASI LOGAM BERAT DI SEDIMEN: STUDI KASUS PADA WADUK SAGULING JAWA BARAT (Heavy Metals Contamination in Sediment: Saguling Reservoir Case Study West Java, Indonesia

    Directory of Open Access Journals (Sweden)

    Yoyok Sudarso

    2005-03-01

    Full Text Available ABSTRAK Waduk Saguling merupakan salah satu waduk cascade yang berlokasi di Jawa Barat, yang sekarang ini mengalami beberapa permasalahan antara lain: proses sedimentasi yangtinggi, korositas turbin, penurunan kualitas air akibat blooming alga, polusi organik, pestisida, dan logam-logam berat yang berasal dari buangan limbah domestik, industri, aktivitas gunung berapi, dan sebagainya. Logam berat di ekosistem akuatik mempunyai kecenderungan untuk berikatan dengan sedimen yang mampu bertindak sebagai sumber polusi sekunder ke kolom air. Penelitian pada tahun 2004 ini bertujuan untuk mengungkap kontaminasi logam berat Cu, Cd, dan Pb pada sedimen Waduk Saguling. Sampling dilakukan tiga kali mulai bulan Juni hingga September 2004 dengan l3 titik stasiun pengamatan. Hasil kontaminasi logam berat pada sedimen di setiap stasiun pengamatan menunjukkan adanya perbedaan yang sangat signifikan diantara masing-masing stasiun pengamatan yaitu: untuk logam Cd (F: 17,803 dan p = 0,00001, Pb (F= 154,343 dan p < 0,01, dan Cu (F:36,499, P<0,000001. Konsentrasi logam berat hasil pengamatan dibandingkan dengan guideline dari kementrian lingkungan Ontario, SEPA, ERL, ERM, PEL, SEL, dan TEL, secara umum menunjukkan bahwa kontaminasi logam Pb dan Cu yang paling berpotensi menimbulkan gangguan pada ekosistem perairan, sedangkan logam Cd masih dibawah ambang batas dari guideline tersebut diatas. Khusus untuk guideline yang berasal dari US-EPAregion Y Great lakes ke tiga logam tersebut diatas sudah masuk dalam kategori terpolusi berat dari St. Gunung Wayang hingga Stasiun Rajamandala.   ABSTRACT Saguling reservoir is one of three cascade reservoirs, which is located in West Java. Nowadays, the reservoir has some serious problems such as: high sedimentation rate, turbine corrosity, water quality depletion caused by blooming algae, organic pollution, pesticide, and heavy metals which are resulted from domestic and industrial wastes, as well as teaching from volcano

  9. In-filled reservoirs serving as sediment archives to analyse soil organic carbon erosion – Taking a closer look at the Karoo rangelands

    DEFF Research Database (Denmark)

    Krenz, Juliane; Greenwood, Philip; Kuhn, Brigitte

    The semi-arid rangelands of the Great Karoo region in South Africa, which are nowadays characterized by badlands on the foot slopes of upland areas and complex gully systems in valley bottoms, have experienced a number of environmental changes. With the settlement of European farmers in the late ......th century agricultural activities increased, leading to overgrazing which probably acted as a trigger to land degradation. As a consequence of higher water demands and shifting rainfall patterns, many dams and small reservoirs have been constructed to provide drinking water for cattle...... or to facilitate irrigation during dry periods. Most of these dams are now filled with sediment and many have become breached, revealing sediment archives that can be used to analyse land use changes as well as carbon erosion and deposition during the last ca. 100 years. In this ongoing project, a combination...

  10. Three types of gas hydrate reservoirs in the Gulf of Mexico identified in LWD data

    Science.gov (United States)

    Lee, Myung Woong; Collett, Timothy S.

    2011-01-01

    High quality logging-while-drilling (LWD) well logs were acquired in seven wells drilled during the Gulf of Mexico Gas Hydrate Joint Industry Project Leg II in the spring of 2009. These data help to identify three distinct types of gas hydrate reservoirs: isotropic reservoirs in sands, vertical fractured reservoirs in shale, and horizontally layered reservoirs in silty shale. In general, most gas hydratebearing sand reservoirs exhibit isotropic elastic velocities and formation resistivities, and gas hydrate saturations estimated from the P-wave velocity agree well with those from the resistivity. However, in highly gas hydrate-saturated sands, resistivity-derived gas hydrate-saturation estimates appear to be systematically higher by about 5% over those estimated by P-wave velocity, possibly because of the uncertainty associated with the consolidation state of gas hydrate-bearing sands. Small quantities of gas hydrate were observed in vertical fractures in shale. These occurrences are characterized by high formation resistivities with P-wave velocities close to those of water-saturated sediment. Because the formation factor varies significantly with respect to the gas hydrate saturation for vertical fractures at low saturations, an isotropic analysis of formation factor highly overestimates the gas hydrate saturation. Small quantities of gas hydrate in horizontal layers in shale are characterized by moderate increase in P-wave velocities and formation resistivities and either measurement can be used to estimate gas hydrate saturations.

  11. The history of a continent from U-Pb ages of zircons from Orinoco River sand and Sm-Nd isotopes in Orinoco basin river sediments

    Science.gov (United States)

    Goldstein, S.L.; Arndt, N.T.; Stallard, R.F.

    1997-01-01

    We report SHRIMP U-Pb ages of 49 zircons from a sand sample from the lower Orinoco River, Venezuela, and Nd model ages of the fine sediment load from the main river and tributaries. The U-Pb ages reflect individual magmatic or metamorphic events, the Sm-Nd model ages reflect average crustal-residence ages of the sediment sources. Together they allow delineation of the crust-formation history of the basement precursors of the sediments. The U-Pb ages range from 2.83 to 0.15 Ga, and most are concordant or nearly so. Discrete age groupings occur at ??? 2.8, ??? 2.1, and ??? 1.1 Ga. The oldest group contains only three samples but is isolated from its closest neighbors by a ??? 600 Ma age gap. Larger age groupings at ??? 2.1 and ??? 1.1 Ga make up about a third and a quarter of the total number of analyses, respectively. The remaining analyses scatter along concordia, and most are younger than 1.6 Ga. The ??? 2.8 and ??? 2.1 Ga ages correspond to periods of crust formation of the Imataca and Trans-Amazonian provinces of the Guyana Shield, respectively, and record intervals of short but intensive continental growth. These ages coincide with ??? 2.9 and ??? 2.1 Ga Nd model ages of sediments from tributaries draining the Archean and Proterozoic provinces of the Guyana Shield, respectively, indicating that the U-Pb ages record the geological history of the crystalline basement of the Orinoco basin. Zircons with ages corresponding to the major orogenies of the North Atlantic continents (the Superior at ??? 2.7 Ga and Hudsonian at 1.7-1.9 Ga) were not found in the Orinoco sample. The age distribution may indicate that South and North America were separated throughout their history. Nd model ages of sediments from the lower Orinoco River and Andean tributaries are ??? 1.9 Ga, broadly within the range displayed by major rivers and dusts. This age does not coincide with known thermal events in the region and reflects mixing of sources with different crust-formation ages. The

  12. Sediment transport in the lower Snake and Clearwater River Basins, Idaho and Washington, 2008–11

    Science.gov (United States)

    Clark, Gregory M.; Fosness, Ryan L.; Wood, Molly S.

    2013-01-01

    /L), and the Middle Fork Clearwater River at Kooskia, Idaho (15 mg/L). The largest measured concentrations of suspended sediment (3,300 and 1,400 mg/L) during a rain-on-snow event in January 2011 were from samples collected at the Potlatch River near Spalding, Idaho, and the Palouse River at Hooper, Washington, respectively. Generally, samples collected from agricultural watersheds had a high percentage of silt and clay-sized suspended sediment, whereas samples collected from forested watersheds had a high percentage of sand. During water years 2009–11, Lower Granite Reservoir received about 10 million tons of suspended sediment from the combined loads of the Snake and Clearwater Rivers. The Snake River accounted for about 2.97 million tons per year (about 89 percent) of the total suspended sediment, 1.48 million tons per year (about 90 percent) of the suspended sand, and about 1.52 million tons per year (87 percent) of the suspended silt and clay. Of the suspended sediment transported to Lower Granite Reservoir, the Salmon River accounted for about 51 percent of the total suspended sediment, about 56 percent of the suspended sand, and about 44 percent of the suspended silt and clay. About 6.2 million tons (62 percent) of the sediment contributed to Lower Granite Reservoir during 2009–11 entered during water year 2011, which was characterized by an above average winter snowpack and sustained spring runoff. A comparison of historical data collected from the Snake River near Anatone with data collected during this study indicates that concentrations of total suspended sediment and suspended sand in the Snake River were significantly smaller during water years 1972–79 than during 2008–11. Most of the increased sediment content in the Snake River is attributable to an increase of sand-size material. During 1972–79, sand accounted for an average of 28 percent of the suspended-sediment load; during 2008–11, sand accounted for an average of 48 percent. Historical data

  13. Evaluation of the concentration of toxic metals and rare ground elements in samples of sediments of the Billings and Guarapiranga systems reservoirs

    International Nuclear Information System (INIS)

    Silva, Larissa de Souza

    2017-01-01

    The excessive urbanization process of the Sao Paulo Metropolitan Region resulted in the loss of the natural characteristics of its water courses causing serious changes in flow and quality regimes. The objective of this study was evaluate the concentration of toxic metals, semi metals As, Sb and Se, and rare earth elements present in surface sediment samples collected at the Billings, Guarapiranga and Rio Grande Reservoirs. The Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sb, Se and Zn elements were analyzed using Optical Emission Spectrometry With Inductively Coupled Plasma (ICP OES). Some major, trace and rare earth elements (Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) were analyzed by the Instrumental Neutron Activation Analysis (INAA) technique. The total Hg concentration was determined by Cold Vapor Atomic Absorption Spectrometry technique (CVAAS). The validation of the methodologies was performed by means of the certified reference material analyses. To assess the sources of anthropogenic contamination, the enrichment factor (EF) and the geoaccumulation index (IGeo) were calculated. The results obtained for both techniques were compared with TEL and PEL oriented values established by CCME (Canadian Council of Ministers of the Environment) and adopted by CETESB (Environmental Company of the Sao Paulo State). All sampling points showed concentration values for toxic metals >TEL and 2 points at Billings Reservoir (BILL02030 and 02100), values > PEL for As, Cr, Cu, Hg, Ni, Pb and Zn, probably due to the entrance of the Pinheiros River waters and drainage basins of the Cocaia and Borore streams. The calculated EF and IGeo values indicated possible anthropogenic contamination for Sb and Se for the elements determined by ICP OES and As, Cr, Sb and Zn, obtained by INAA. The Billings reservoir presented, in general, the highest concentrations for the analyzed elements, indicating a poor quality of its sediments. This study confirms the need of a frequent

  14. Sedimentation

    Science.gov (United States)

    Cliff R. Hupp; Michael R. Schening

    2000-01-01

    Sedimentation is arguably the most important water-quality concern in the United States. Sediment trapping is cited frequently as a major function of riverine-forested wetlands, yet little is known about sedimcntation rates at the landscape scale in relation to site parameters, including woody vegetation type, elevation, velocity, and hydraulic connection to the river...

  15. Mineralogy, morphology, and textural relationships in coatings on quartz grains in sediments in a quartz-sand aquifer

    Science.gov (United States)

    Zhang, Shouliang; Kent, Douglas B.; Elbert, David C.; Shi, Zhi; Davis, James A.; Veblen, David R.

    2011-01-01

    Mineralogical studies of coatings on quartz grains and bulk sediments from an aquifer on Western Cape Cod, Massachusetts, USA were carried out using a variety of transmission electron microscopy (TEM) techniques. Previous studies demonstrated that coatings on quartz grains control the adsorption properties of these sediments. Samples for TEM characterization were made by a gentle mechanical grinding method and focused ion beam (FIB) milling. The former method can make abundant electron-transparent coating assemblages for comprehensive and quantitative X-ray analysis and the latter technique protects the coating texture from being destroyed. Characterization of the samples from both a pristine area and an area heavily impacted by wastewater discharge shows similar coating textures and chemical compositions. Major constituents of the coating include Al-substituted goethite and illite/chlorite clays. Goethite is aggregated into well-crystallized domains through oriented attachment resulting in increased porosity. Illite/chlorite clays with various chemical compositions were observed to be mixed with goethite aggregates and aligned sub-parallel to the associated quartz surface. The uniform spatial distribution of wastewater-derived phosphorus throughout the coating from the wastewater-contaminated site suggests that all of the coating constituents, including those adjacent to the quartz surface, are accessible to groundwater solutes. Both TEM characterization and chemical extraction results indicate there is a significantly greater amount of amorphous iron oxide in samples from wastewater discharge area compared to those from the pristine region, which might reflect the impact of redox cycling of iron under the wastewater-discharge area. Coating compositions are consistent with the moderate metal and oxy-metalloid adsorption capacities, low but significant cation exchange capacities, and control of iron(III) solubility by goethite observed in reactive transport

  16. Sedimentation and Its Impacts/Effects on River System and Reservoir Water Quality: case Study of Mazowe Catchment, Zimbabwe

    Science.gov (United States)

    Tundu, Colleta; Tumbare, Michael James; Kileshye Onema, Jean-Marie

    2018-04-01

    Sediment delivery into water sources and bodies results in the reduction of water quantity and quality, increasing costs of water purification whilst reducing the available water for various other uses. The paper gives an analysis of sedimentation in one of Zimbabwe's seven rivers, the Mazowe Catchment, and its impact on water quality. The Revised Universal Soil Loss Equation (RUSLE) model was used to compute soil lost from the catchment as a result of soil erosion. The model was used in conjunction with GIS remotely sensed data and limited ground observations. The estimated annual soil loss in the catchment indicates soil loss ranging from 0 to 65 t ha yr-1. Bathymetric survey at Chimhanda Dam showed that the capacity of the dam had reduced by 39 % as a result of sedimentation and the annual sediment deposition into Chimhanda Dam was estimated to be 330 t with a specific yield of 226 t km-2 yr-1. Relationship between selected water quality parameters, TSS, DO, NO3, pH, TDS, turbidity and sediment yield for selected water sampling points and Chimhanda Dam was analyzed. It was established that there is a strong positive relationship between the sediment yield and the water quality parameters. Sediment yield showed high positive correlation with turbidity (0.63) and TDS (0.64). Water quality data from Chimhanda treatment plant water works revealed that the quality of water is deteriorating as a result of increase in sediment accumulation in the dam. The study concluded that sedimentation can affect the water quality of water sources.

  17. Long-term variations in sediment heavy metals of a reservoir with changing trophic states: Implications for the impact of climate change.

    Science.gov (United States)

    Wu, Qiong; Qi, Jun; Xia, Xinghui

    2017-12-31

    Two dated sediment cores from the Miyun Reservoir of Beijing in China were analyzed to reconstruct the pollution history of heavy metals including cadmium (Cd), chromium (Cr), iron (Fe), nickel (Ni), and zinc (Zn) as well as phosphorus (P). Enrichment factor (EF) and geoaccumulation index (I geo ) were applied to assess the enrichment status of heavy metals. Average EF and I geo values indicated that the studied heavy metals in the sediments mainly originated from non-point source pollution and soil-water erosion, showing low ecological risks. In addition, correlation analysis and principal component analysis (PCA) identified that Cd, Zn, and P were mainly from agricultural diffusion pollution caused by utilization of the phosphate fertilizer; Zn, Ni, and Cr originated from soil erosion. PCA analysis was further conducted to investigate the relationships among meteorological factors, algae-dominant total organic carbon (TOC), and heavy metals. Results showed that algae-dominant TOC had strong positive correlation with temperature, which can be explained by that increased temperature accelerated the growth of algae. Meanwhile the opposite loadings between algae-dominant TOC and heavy metal suggested that primary production played an important role in migration and transformation of metals. Moreover, stepwise multiple regression models showed that Fe was sensitive to temperature, which accounted for approximately 39.0% and 40.1% of the variations in Fe of two sediment cores, respectively. Fe showed significant decreasing trends during the past 50years. Reductive environment of water-sediment interface caused by increasing temperature probably contributed to the restoration of ferric iron, resulting in the release of soluble Fe to overlying waters. Future climate change with elevated temperature and extreme weather events will aggravate the ecological risk of heavy metals in water environment due to the enhanced leaching effect and non-point source pollution as well

  18. Sedimentary controls on modern sand grain coat formation

    Science.gov (United States)

    Dowey, Patrick J.; Worden, Richard H.; Utley, James; Hodgson, David M.

    2017-05-01

    Coated sand grains can influence reservoir quality evolution during sandstone diagenesis. Porosity can be reduced and fluid flow restricted where grain coats encroach into pore space. Conversely pore-lining grain coats can restrict the growth of pore-filling quartz cement in deeply buried sandstones, and thus can result in unusually high porosity in deeply buried sandstones. Being able to predict the distribution of coated sand grains within petroleum reservoirs is thus important to help find good reservoir quality. Here we report a modern analogue study of 12 sediment cores from the Anllóns Estuary, Galicia, NW Spain, collected from a range of sub-environments, to help develop an understanding of the occurrence and distribution of coated grains. The cores were described for grain size, bioturbation and sedimentary structures, and then sub-sampled for electron and light microscopy, laser granulometry, and X-ray diffraction analysis. The Anllóns Estuary is sand-dominated with intertidal sand flats and saltmarsh environments at the margins; there is a shallowing/fining-upwards trend in the estuary-fill succession. Grain coats are present in nearly every sample analysed; they are between 1 μm and 100 μm thick and typically lack internal organisation. The extent of grain coat coverage can exceed 25% in some samples with coverage highest in the top 20 cm of cores. Samples from muddy intertidal flat and the muddy saltmarsh environments, close to the margins of the estuary, have the highest coat coverage (mean coat coverage of 20.2% and 21.3%, respectively). The lowest mean coat coverage occurs in the sandy saltmarsh (10.4%), beyond the upper tidal limit and sandy intertidal flat environments (8.4%), close to the main estuary channel. Mean coat coverage correlates with the concentration of clay fraction. The primary controls on the distribution of fine-grained sediment, and therefore grain coat distribution, are primary sediment transport and deposition processes that

  19. Characterization of deep-marine clastic sediments from foreland basins: Outcrop-derived concepts for exploration, production and reservoir modelling. Doctoral thesis; Karakterizering van diep-mariene klastische sedimenten uit voorland bekkens: Aan ontsluitingen ontleende concepten voor exploratie, produktie en reservoir modellering

    Energy Technology Data Exchange (ETDEWEB)

    Schuppers, J D

    1995-02-20

    Deep-marine clastic sediments are the host for many prolific hydrocarbon reservoirs. The sandbodies that form these reservoirs show a wide variety in shape, spatial arrangement, and internal structure. The outcrops studied for this thesis pertain to the fill of circum-mediterranean foreland basins in Spain and Greece. The outcrops have allowed the description of the multiscale anatomy of sandbodies that cover a wide range of depositional settings. The descriptions are focused on those features that are most likely to influence the flow of fluids through analogous reservoirs of similar construction. Extensive use was made of photomosaics to outline the large-scale geometries and stacking modes of the sandbodies. The sediments studied form the basis for seven `reservoir models` that are both descriptive and conceptual.

  20. Implications of S1 tephra findings in Dead Sea and Tayma palaeolake sediments for marine reservoir age estimation and palaeoclimate synchronisation

    Science.gov (United States)

    Neugebauer, Ina; Wulf, Sabine; Schwab, Markus J.; Serb, Johanna; Plessen, Birgit; Appelt, Oona; Brauer, Achim

    2017-08-01

    Here we report on the first findings of a cryptotephra in the Holocene lacustrine sediment records of the Dead Sea and Tayma palaeolake (NW Arabian Peninsula). The major element glass composition of this rhyolitic tephra is identical to the distal 'S1' tephra layer identified in the Yammoûneh palaeolake (Lebanon), in a marine sediment record from the SE Levantine basin and in the Sodmein Cave archaeological site in Egypt. The S1 tephra corresponds to the early Holocene 'Dikkartın' dome eruption of the Erciyes Dağ volcano in central Anatolia (Turkey) and has been dated in the marine record at 8830 ± 140 cal yr BP. We present new age estimates of the S1 tephra based on radiocarbon dating of terrestrial plant remains and pollen concentrates revealing ages of 8939 ± 83 cal yr BP in the Dead Sea sediments and 9041 ± 254 cal yr BP in Tayma. The precise date from the Dead Sea allows refining the early Holocene marine reservoir age in the SE Levantine Sea to ca. 320 ± 50 years. Synchronisation of marine and terrestrial palaeoclimate records in the eastern Mediterranean region using the S1 tephra further suggests a time-transgressive expansion of the early Holocene humid period.

  1. Applying 1D Sediment Models to Reservoir Flushing Studies: Measuring, Monitoring, and Modeling the Spencer Dam Sediment Flush with HEC-RAS

    Science.gov (United States)

    2016-07-01

    by Paul Boyd and Stanford Gibson PURPOSE: The purposes of this Coastal and Hydraulics Engineering Technical Note (CHETN) are (1) to summarize the...HEC-RAS), and (2) to determine the model’s applicability for flushing applications. HEC-RAS is a one- dimensional (1D) numerical hydraulics and... reduces the usable space in Federal reservoirs and depletes downstream reaches of ecologically important substrates. The USACE and other Federal agencies

  2. Seismic and Rockphysics Diagnostics of Multiscale Reservoir Textures

    Energy Technology Data Exchange (ETDEWEB)

    Gary Mavko

    2005-07-01

    This final technical report summarizes the results of the work done in this project. The main objective was to quantify rock microstructures and their effects in terms of elastic impedances in order to quantify the seismic signatures of microstructures. Acoustic microscopy and ultrasonic measurements were used to quantify microstructures and their effects on elastic impedances in sands and shales. The project led to the development of technologies for quantitatively interpreting rock microstructure images, understanding the effects of sorting, compaction and stratification in sediments, and linking elastic data with geologic models to estimate reservoir properties. For the public, ultimately, better technologies for reservoir characterization translates to better reservoir development, reduced risks, and hence reduced energy costs.

  3. Assessment of pollution and identification of sources of heavy metals in the sediments of Changshou Lake in a branch of the Three Gorges Reservoir.

    Science.gov (United States)

    Liang, Ao; Wang, Yechun; Guo, Hongtao; Bo, Lei; Zhang, Sheng; Bai, Yili

    2015-10-01

    To assess the heavy metal pollution in Changshou Lake, sediments were collected from nine sites at three periods (dry, normal, and wet) in 2013. The Hg, As, Cr, Cd, Pb, Cu, and Zn levels were then determined. The index of geoaccumulation (I geo) and the sediment pollution index (SPI) were applied to the sediment assessment, and Pearson's correlation analysis and factor analysis (FA) were performed to identify common pollution sources in the basin. The results showed that heavy metals presented significant spatial variations with Cr, Cd, Pb, Cu, Zn, Hg, and As concentrations of 29.66~42.58, 0.62~0.91, 24.91~37.96, 21.18~74.91, 41.65~86.86, 0.079~0.152, and 20.17~36.88 mg kg(-1), respectively, and no obvious variations were found among the different periods. The average contents of the metals followed the order Zn > Cu > Cr > Pb > As > Cd > Hg, which showed a high pollution in the sediments collected from open water and at the river mouth. The assessment results indicated that toxic heavy metals presented obvious pollution with I Hg of 0.64~1.36 (moderately polluted), I Cd of 1.66~2.22 (moderately to heavily polluted), and I As of 1.21~2.07 (moderately to heavily polluted). The heavy metal pollution states followed the order Cd > As > Hg > Cu > Pb > Zn > Cr, and the SPI showed that the sediment collected from open water area was more polluted than those obtained from the tributaries and the river mouth. Cr, Cd, Hg, Pb, Cu, As, and Zn were mainly attributed to sediment weathering with Hg, Pb, and Cu and partially due to domestic sewage from the upper reaches. These results indicate that the more attention should be paid to the inner loads of sediment in order to achieve improvements in reservoir water quality after the control of external pollution.

  4. A sedimentation study in the Muda catchment area using nuclear techniques

    International Nuclear Information System (INIS)

    Kamarudin Samuding; Wan Zakaria Wan Muhamad Tahir; Roslan Mohd Ali; Juhari Yusuf

    2002-01-01

    A study on the sediment size distribution and determination of sediment density profile was conducted in a selected area of the Muda Dam catchment area, Kedah. The objective of the study was to establish baseline data of the input sedimentation with regard to the effects of development within the catchment in the future. Three main sampling locations were identified, namely at Sungai Teliang, Sungai Muda and the Muda Reservoir. Results showed that the grain size distribution of sediment generally ranged from clay to gravel size. In the reservoir and downstream the river, most of the samples studied consisted of fine sediment Le, silt and clay (< 63 μm). However, sediment distribution in the upstream section of Sungai Teliang mainly consisted of fine to coarse sand. Based on the sediment distribution profile analysis, the study site could be divided into two parts comprising the dynamic area (region) covering selected locations along the river and the deposited sediment in the reservoir. Measurement of sediment thickness was performed using nuclear gauges, i.e. direct transmission and backscattering methods. The result also showed that the thickness of bed sediment varied from one location to another, whereby the thickness variation could reach up to 0.75 metre in some areas. This study could assist local authorities (AMDA) in identifying the rates and sources of accumulated sediment as well as quality and quantity of water in the study area in order to sustain distribution of good quality water to the farmers. (Author)

  5. 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....

  6. Natural radionuclides from U-238 and Th-232 series and inorganic chemical characterization of soil profiles and sediment cores of the TaiaÇUpeba Reservoir, SÃO Paulo, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Souza, J.M.; Damatto, S.R.; Surkov, A.M.; Silva, A.R.; Maduar, M.F.; Gonçalves, P.N., E-mail: jmarques@ipen.br, E-mail: damatto@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Leonardo, L. [Centro Universitário São Camilo (Campus Ipiranga), São Paulo, SP (Brazil)

    2017-07-01

    Taiaçupeba reservoir, located in the state of São Paulo, Brazil, belongs to Producer System of Alto Tietê (Sistema Produtor Alto Tietê) and it is responsible for water supply for about 3.1million of people. The water quality of a reservoir is very important, but this is reduced by the increase of environmental degradation of the soil around the reservoir and its different uses. The study of soil profiles and sediment cores is an important tool for understanding the geophysical and geochemical aspects of an aquatic ecosystem. The objective of this work was to present the natural radionuclides {sup 238}U, {sup 226}Ra, {sup 210}Pb, {sup 232}Th, {sup 228}Th,{sup 228}Ra and {sup 40}K activity concentrations and also the inorganic chemical characterization of four soil profiles and four sediment cores collected in the area of influence area of Taiaçupeba reservoir. The analytical techniques, gamma spectrometry and instrumental neutron activation analysis were used in the determination. In the soil profiles the highest activity concentrations were obtained for the radionuclides {sup 40}K and {sup 228}Th and the lowest for {sup 210}Pb; in the sediment cores the highest activity concentrations were obtained for the radionuclide {sup 210}Pb and the lowest for {sup 226}Ra and {sup 228}Ra. For the inorganic chemical characterization the highest values obtained were for Na, As and Sb; in a sediment core a very high concentration was obtained for the element Zn indicating a probable accumulation of this element inside the reservoir; enrichment factor was used to evaluate a possible anthropic contamination in the soil and sediment at the margins of Taiaçupeba reservoir. (author)

  7. Natural radionuclides from U-238 and Th-232 series and inorganic chemical characterization of soil profiles and sediment cores of the TaiaÇUpeba Reservoir, SÃO Paulo, Brazil

    International Nuclear Information System (INIS)

    Souza, J.M.; Damatto, S.R.; Surkov, A.M.; Silva, A.R.; Maduar, M.F.; Gonçalves, P.N.; Leonardo, L.

    2017-01-01

    Taiaçupeba reservoir, located in the state of São Paulo, Brazil, belongs to Producer System of Alto Tietê (Sistema Produtor Alto Tietê) and it is responsible for water supply for about 3.1million of people. The water quality of a reservoir is very important, but this is reduced by the increase of environmental degradation of the soil around the reservoir and its different uses. The study of soil profiles and sediment cores is an important tool for understanding the geophysical and geochemical aspects of an aquatic ecosystem. The objective of this work was to present the natural radionuclides 238 U, 226 Ra, 210 Pb, 232 Th, 228 Th, 228 Ra and 40 K activity concentrations and also the inorganic chemical characterization of four soil profiles and four sediment cores collected in the area of influence area of Taiaçupeba reservoir. The analytical techniques, gamma spectrometry and instrumental neutron activation analysis were used in the determination. In the soil profiles the highest activity concentrations were obtained for the radionuclides 40 K and 228 Th and the lowest for 210 Pb; in the sediment cores the highest activity concentrations were obtained for the radionuclide 210 Pb and the lowest for 226 Ra and 228 Ra. For the inorganic chemical characterization the highest values obtained were for Na, As and Sb; in a sediment core a very high concentration was obtained for the element Zn indicating a probable accumulation of this element inside the reservoir; enrichment factor was used to evaluate a possible anthropic contamination in the soil and sediment at the margins of Taiaçupeba reservoir. (author)

  8. Trace metal distributions in the sediments from river-reservoir systems: case of the Congo River and Lake Ma Vallée, Kinshasa (Democratic Republic of Congo).

    Science.gov (United States)

    Mwanamoki, Paola M; Devarajan, Naresh; Niane, Birane; Ngelinkoto, Patience; Thevenon, Florian; Nlandu, José W; Mpiana, Pius T; Prabakar, Kandasamy; Mubedi, Josué I; Kabele, Christophe G; Wildi, Walter; Poté, John

    2015-01-01

    The contamination of drinking water resources by toxic metals is a major problem in many parts of the world, particularly in dense populated areas of developing countries that lack wastewater treatment facilities. The present study characterizes the recent evolution with time of some contaminants deposited in the Congo River and Lake Ma Vallée, both located in the vicinity of the large city of Kinshasa, capital of Democratic Republic of Congo (DRC). Physicochemical parameters including grain size distribution, organic matter and trace element concentrations were measured in sediment cores sampled from Congo River (n = 3) and Lake Ma Vallée (n = 2). The maximum concentration of trace elements in sediment profiles was found in the samples from the sites of Pool Malebo, with the values of 107.2, 111.7, 88.6, 39.3, 15.4, 6.1 and 4.7 mg kg(-1) for Cr, Ni, Zn, Cu, Pb, As and Hg, respectively. This site, which is characterized by intense human activities, is especially well known for the construction of numerous boats that are used for regular navigation on Congo River. Concerning Lake Ma Vallée, the concentration of all metals are generally low, with maximum values of 26.3, 53.6, 16.1, 15.3, 6.5 and 1.8 mg kg(-1) for Cr, Ni, Zn, Cu, Pb and As, respectively. However, the comparison of the metal profiles retrieved from the different sampled cores also reveals specific variations. The results of this study point out the sediment pollution by toxic metals in the Congo River Basin. This research presents useful tools for the evaluation of sediment contamination of river-reservoir systems.

  9. Sediment-Overlying Water Relationships Affecting Wintertime Dissolved Oxygen Conditions in the Big Eau Pleine Reservoir, Wisconsin.

    Science.gov (United States)

    1992-07-01

    22202-4302. and to the Office of Managel ent and Bidget . P worki Reduction Pfo4ect(07T4-016 Wahington. DC 20S03. -1. AGENCY USE ONLY (Leave blank) 2...higher pool elevation can not be maintained, it is likely that additional aerators must be installed for incremental use to meet periodic heavy oxygen...install additional aerators throughout the reservoir for incremental use as needed to enhance oxygen diffusion processes. The difficulty with this

  10. Tres Marias Reservoir, Minas Gerais State: Study of the dispersion of suspended sediments in surface waters using orbital images

    Science.gov (United States)

    Dejesusparada, N. (Principal Investigator); Sausen, T. M.

    1980-01-01

    Computer compatible tapes from LANDSAT were used to compartmentalize the Ires Marias reservoir according to respective grey level spectral response. Interactive and automatic, supervised classification, was executed from the IMAGE-100 system. From the simple correlation analysis and graphic representation, it is shown that grey tone levels are inversely proportional to Secchi Depth values. It is further shown that the most favorable period to conduct an analysis of this type is during the rainy season.

  11. Temporal and basin-specific population trends of quagga mussels on soft sediment of a multi-basin reservoir

    Science.gov (United States)

    Caldwell, Timothy J; Rosen, Michael R.; Chandra, Sudeep; Acharya, Kumud; Caires, Andrea M; Davis, Clinton J.; Thaw, Melissa; Webster, Daniel M.

    2015-01-01

    Invasive quagga (Dreissena bugnesis) and zebra (Dreissena ploymorpha) mussels have rapidly spread throughout North America. Understanding the relationships between environmental variables and quagga mussels during the early stages of invasion will help management strategies and allow researchers to predict patterns of future invasions. Quagga mussels were detected in Lake Mead, NV/AZ in 2007, we monitored early invasion dynamics in 3 basins (Boulder Basin, Las Vegas Bay, Overton Arm) bi-annually from 2008-2011. Mean quagga density increased over time during the first year of monitoring and stabilized for the subsequent two years at the whole-lake scale (8 to 132 individuals·m-2, geometric mean), in Boulder Basin (73 to 875 individuals·m-2), and in Overton Arm(2 to 126 individuals·m-2). In Las Vegas Bay, quagga mussel density was low (9 to 44 individuals·m-2), which was correlated with high sediment metal concentrations and warmer (> 30°C) water temperatures associated with that basin. Carbon content in the sediment increased with depth in Lake Mead and during some sampling periods quagga density was also positively correlated with depth, but more research is required to determine the significance of this interaction. Laboratory growth experiments suggested that food quantity may limit quagga growth in Boulder Basin, indicating an opportunity for population expansion in this basin if primary productivity were to increase, but was not the case in Overton Arm. Overall quagga mussel density in Lake Mead is highly variable and patchy, suggesting that temperature, sediment size, and sediment metal concentrations, and sediment carbon content all contribute to mussel distribution patterns. Quagga mussel density in the soft sediment of Lake Mead expanded during initial colonization, and began to stabilize approximately 3 years after the initial invasion.

  12. Uranium mineralization rules controlled by sedimentation in Bayanwula region in Erlian basin

    International Nuclear Information System (INIS)

    Lu Chao

    2012-01-01

    Uranium mineralization is closely related to sedimentation in Bayanwula region in Erlian Basin. Clarifying the relation of sedimentation and Uranium Mineralization Through detailed analysis of vertical sequences, stratigraphic correlation and the heterogeneity of sand body. Study show that the of development characteristics of sequences of Bayanwula region control the vertical positioning of favorable sand, the skeleton sand bodies of LST in upper Saihan formation is the most favorable reservoir space for uranium. Uranium mineralization is closely related with the heterogeneity of the sand bodies of upper Saihan formation. the heterogeneity of Sand body is mainly reflected in plane and vertical. In plane, with the research of the sand distributed system of upper Saihan formation, the change position of sandstone thickness and sand rate, the position of the variation of shape and trend of sand body, and the change position of sand body character and genesis are most favorable for uranium mineralization. In vertical, the number of layers and thickness of isolated barrier bed not only control the thickness of oxide sandstone. but also they are associated with the distribution of uranium mineralization; The evolution of sedimentary basins created Bayanwula uranium deposits. There is a second order sequence boundary between the upper Saihan formation and the Erlian formation of Late Cretaceous, which is a long-term exposure and erosion unconformity, resulting in the partly erosion of the upper Saihan formation, providing the best conditions of the penetration of the uranium-bearing oxygen water and the development of phreatic oxidation and interlayer oxidation zone. (author)

  13. Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the American Falls Reservoir area, Idaho, 1988-89

    Science.gov (United States)

    Low, Walton H.; Mullins, William H.

    1990-01-01

    Increased concern about the quality of irrigation drainage and its potential effects on human health, fish, and wildlife prompted the Department of the Interior to begin a program during late 1985 to identify irrigation-induced water-quality problems that might exist in the Western States. During `988, the Task Group on Irrigation Drainage selected the American Falls Reservoir area, Idaho, for study to determine whether potentially toxic concentrations of trace elements or organochlorine compounds existed in water, bottom sediment, and biota. The 91-square mile American Falls Reservoir has a total capacity of 1.7 million acre-feet and is used primarily for irrigation-water supply and power generation. Irrigated land upstream from the reservoir totals about 550,000 acres. Total water inflow to the reservoir is about 5.8 million acre-feet per year, of which about 63 percent is from surface-water runoff, 33 percent is from ground-water discharge, and about 4 percent is from ungaged tributaries, canals, ditches, sloughs, and precipitation. Ground-water discharge to the reservoir originates, in part, from irrigation of land upstream from and adjacent to the reservoir. The 1988 water year was a drought year, and water discharge was about 34 percent less than during 1939-88. Water samples were collected during the post-irrigation (October 1987) and irrigation (July 1988) seasons and were analyzed for major ions and trace elements. Bottom-sediment samples were collected during the irrigation season and were analyzed for trace elements and organochlorine compounds. Biota samples were collected during May, June, July, and August 1988 and were analyzed for trace elements and organochlorine compounds. Dissolved-solids concentrations in water ranged from 216 to 561 milligrams per liter. The similarity of dissolved-solids concentrations between the irrigation and post-irrigation seasons can be attributed to the large volume of ground-water discharge in the study area. Most trace

  14. Effects of the Upper Taum Sauk Reservoir Embankment Breach on the Surface-Water Quality and Sediments of the East Fork Black River and the Black River, Southeastern Missouri - 2006-07

    Science.gov (United States)

    Barr, Miya N.

    2009-01-01

    On December 14, 2005, a 680-foot wide section of the upper reservoir embankment of the Taum Sauk pump-storage hydroelectric powerplant located in Reynolds County, Missouri, suddenly failed. This catastrophic event sent approximately 1.5 billion gallons of water into the Johnson's Shut-Ins State Park and into the East Fork Black River, and deposited enormous quantities of rock, soil, and vegetation in the flooded areas. Water-quality data were collected within and below the impacted area to study and document the changes to the riverene system. Data collection included routine, event-based, and continuous surface-water quality monitoring as well as suspended- and streambed-sediment sampling. Surface water-quality samples were collected and analyzed for a suite of physical and chemical constituents including: turbidity; nutrients; major ions such as calcium, magnesium, and potassium; total suspended solids; total dissolved solids; trace metals such as aluminum, iron, and lead; and suspended-sediment concentrations. Suspended-sediment concentrations were used to calculate daily sediment discharge. A peculiar blue-green coloration on the water surface of the East Fork Black River and Black River was evident downstream from the lower reservoir during the first year of the study. It is possible that this phenomenon was the result of 'rock flour' occurring when the upper reservoir embankment was breached, scouring the mountainside and producing extremely fine sediment particles, or from the alum-based flocculent used to reduce turbidity in the lower reservoir. It also was determined that no long-term effects of the reservoir embankment breach are expected as the turbidity and concentrations of trace metals such as total recoverable aluminum, dissolved aluminum, dissolved iron, and suspended-sediment concentration graphically decreased over time. Larger concentrations of these constituents during the beginning of the study also could be a direct result of the alum

  15. Evaluation of the concentrations of rare earth elements, metals and traces in sediments of the Graminha Reservoir, São Paulo, SP, Brazil by Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Junqueira, Lucas S.; Fávaro, Déborah I.T.; Silva, Sharlleny A.

    2017-01-01

    Sediment profiles were collected in the Graminha (Caconde) supply reservoir, SP, in Aug / 2014 (points 1 and 4). The analytical technique of Neutral Activation with Instrumental Neutrons (INAA) was used and the determined elements were: As, Ba, Br, Ca, Co, Cr, Cs, Fe, Hf, K, Na, Rb, Sb, Ta, Th, U and Zn and the rare earth elements (ETRs) (Ce, Eu, La, Lu, Nd, Sm, Sc, Tb and Yb). The concentration values for the elements As, Cr and Zn were compared to the concentration guideline values (TEL and PEL) established by CCME (Canada) and adopted by CETESB. The sediments were classified as of good or optimal quality, for these 3 elements. The values found in the last slices of profile 1 (depth 90 cm) were taken as baseline values and from these values, the enrichment factors (FE) and the Geoacumulation Index (IGeo) were calculated. Values of FE> 1.5 were found, mainly, for the ETRs, U and Th, in both points, indicative of presence of anthropic contribution. The IGeo values confirmed FE values, with values of 1

  16. Bacterial diversity in the sediments of a temperate artificial lake, Rapel reservoir Diversidad bacteriana en sedimentos de un lago artificial temperado, embalse Rapel

    Directory of Open Access Journals (Sweden)

    CRISTINA DORADOR

    2007-06-01

    Full Text Available Rapel reservoir is an eutrophic system in Chile that has undergone a series of anthropogenic impacts in recent decades. To provide a better understanding of the processes occurring in the reservoir, we examined bacterial composition from surface sediments using traditional microbiology techniques and molecular biology tools. Our results showed significant temporal variation in the physical and chemical composition of the water column, but no depth-related differences during the study period. To detect temporal changes in bacterial composition, cultivable heterotrophic bacteria, heterotrophic iron oxidizing bacteria, and sulfate-reducing bacteria were extracted from the surface sediments and their concentration measured. Microbial diversity in sediments was represented by closest relatives of eight different bacterial phyla. The most frequently recovered phylotypes in the clone library of 16S rDNA were related to sulfate-reducing bacteria belong to the Deltaproteobacteria groupEl embalse Rapel es un sistema eutrófico en Chile que ha experimentado diversos impactos antropogénicos en las últimas décadas. Para conocer mejor los posibles procesos que ocurren en el embalse, la composición bacteriana fue estudiada en la zona superficial de los sedimentos utilizando técnicas microbiológicas tradicionales y herramientas de biología molecular. Nuestros resultados mostraron variación temporal significativa en la composición física y química del agua, no encontrándose diferencias de las variables medidas entre superficie y fondo en la columna de agua durante el período de estudio. Para detectar cambios temporales en la concentración y composición bacteriana, se midieron bacterias heterótrofas, heterótrofas oxidantes de fierro y bacterias reductoras de sulfato extraídas de la superficie de los sedimentos. La diversidad bacteriana en los sedimentos estuvo representada por 8 diferentes Phyla del dominio Bacteria. Los filotipos m

  17. LOSCAR: Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir Model v2.0.4

    Directory of Open Access Journals (Sweden)

    R. E. Zeebe

    2012-01-01

    Full Text Available The LOSCAR model is designed to efficiently compute the partitioning of carbon between ocean, atmosphere, and sediments on time scales ranging from centuries to millions of years. While a variety of computationally inexpensive carbon cycle models are already available, many are missing a critical sediment component, which is indispensable for long-term integrations. One of LOSCAR's strengths is the coupling of ocean-atmosphere routines to a computationally efficient sediment module. This allows, for instance, adequate computation of CaCO3 dissolution, calcite compensation, and long-term carbon cycle fluxes, including weathering of carbonate and silicate rocks. The ocean component includes various biogeochemical tracers such as total carbon, alkalinity, phosphate, oxygen, and stable carbon isotopes. LOSCAR's configuration of ocean geometry is flexible and allows for easy switching between modern and paleo-versions. We have previously published applications of the model tackling future projections of ocean chemistry and weathering, pCO2 sensitivity to carbon cycle perturbations throughout the Cenozoic, and carbon/calcium cycling during the Paleocene-Eocene Thermal Maximum. The focus of the present contribution is the detailed description of the model including numerical architecture, processes and parameterizations, tuning, and examples of input and output. Typical CPU integration times of LOSCAR are of order seconds for several thousand model years on current standard desktop machines. The LOSCAR source code in C can be obtained from the author by sending a request to loscar.model@gmail.com.

  18. 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

  19. Estimating accumulation rates and physical properties of sediment behind a dam: Englebright Lake, Yuba River, northern California

    Science.gov (United States)

    Snyder, Noah P.; Rubin, David M.; Alpers, Charles N.; Childs, Jonathan R.; Curtis, Jennifer A.; Flint, Lorraine E.; Wright, Scott A.

    2004-01-01

    Studies of reservoir sedimentation are vital to understanding scientific and management issues related to watershed sediment budgets, depositional processes, reservoir operations, and dam decommissioning. Here we quantify the mass, organic content, and grain-size distribution of a reservoir deposit in northern California by two methods of extrapolating measurements of sediment physical properties from cores to the entire volume of impounded material. Englebright Dam, completed in 1940, is located on the Yuba River in the Sierra Nevada foothills. A research program is underway to assess the feasibility of introducing wild anadromous fish species to the river upstream of the dam. Possible management scenarios include removing or lowering the dam, which could cause downstream transport of stored sediment. In 2001 the volume of sediments deposited behind Englebright Dam occupied 25.5% of the original reservoir capacity. The physical properties of this deposit were calculated using data from a coring campaign that sampled the entire reservoir sediment thickness (6–32 m) at six locations in the downstream ∼3/4 of the reservoir. As a result, the sediment in the downstream part of the reservoir is well characterized, but in the coarse, upstream part of the reservoir, only surficial sediments were sampled, so calculations there are more uncertain. Extrapolation from one-dimensional vertical sections of sediment sampled in cores to entire three-dimensional volumes of the reservoir deposit is accomplished via two methods, using assumptions of variable and constant layer thickness. Overall, the two extrapolation methods yield nearly identical estimates of the mass of the reservoir deposit of ∼26 × 106 metric tons (t) of material, of which 64.7–68.5% is sand and gravel. Over the 61 year reservoir history this corresponds to a maximum basin-wide sediment yield of ∼340 t/km2/yr, assuming no contribution from upstream parts of the watershed impounded by other dams. The

  20. Application of random seismic inversion method based on tectonic model in thin sand body research

    Science.gov (United States)

    Dianju, W.; Jianghai, L.; Qingkai, F.

    2017-12-01

    The oil and gas exploitation at Songliao Basin, Northeast China have already progressed to the period with high water production. The previous detailed reservoir description that based on seismic image, sediment core, borehole logging has great limitations in small scale structural interpretation and thin sand body characterization. Thus, precise guidance for petroleum exploration is badly in need of a more advanced method. To do so, we derived the method of random seismic inversion constrained by tectonic model.It can effectively improve the depicting ability of thin sand bodies, combining numerical simulation techniques, which can credibly reducing the blindness of reservoir analysis from the whole to the local and from the macroscopic to the microscopic. At the same time, this can reduce the limitations of the study under the constraints of different geological conditions of the reservoir, accomplish probably the exact estimation for the effective reservoir. Based on the research, this paper has optimized the regional effective reservoir evaluation and the productive location adjustment of applicability, combined with the practical exploration and development in Aonan oil field.

  1. Large-scale dam removal on the Elwha River, Washington, USA: source-to-sink sediment budget and synthesis

    Science.gov (United States)

    Warrick, Jonathan A.; Bountry, Jennifer A.; East, Amy E.; Magirl, Christopher S.; Randle, Timothy J.; Gelfenbaum, Guy R.; Ritchie, Andrew C.; Pess, George R.; Leung, Vivian; Duda, Jeff J.

    2015-01-01

    Understanding landscape responses to sediment supply changes constitutes a fundamental part of many problems in geomorphology, but opportunities to study such processes at field scales are rare. The phased removal of two large dams on the Elwha River, Washington, exposed 21 ± 3 million m3, or ~ 30 million tonnes (t), of sediment that had been deposited in the two former reservoirs, allowing a comprehensive investigation of watershed and coastal responses to a substantial increase in sediment supply. Here we provide a source-to-sink sediment budget of this sediment release during the first two years of the project (September 2011–September 2013) and synthesize the geomorphic changes that occurred to downstream fluvial and coastal landforms. Owing to the phased removal of each dam, the release of sediment to the river was a function of the amount of dam structure removed, the progradation of reservoir delta sediments, exposure of more cohesive lakebed sediment, and the hydrologic conditions of the river. The greatest downstream geomorphic effects were observed after water bodies of both reservoirs were fully drained and fine (silt and clay) and coarse (sand and gravel) sediments were spilling past the former dam sites. After both dams were spilling fine and coarse sediments, river suspended-sediment concentrations were commonly several thousand mg/L with ~ 50% sand during moderate and high river flow. At the same time, a sand and gravel sediment wave dispersed down the river channel, filling channel pools and floodplain channels, aggrading much of the river channel by ~ 1 m, reducing river channel sediment grain sizes by ~ 16-fold, and depositing ~ 2.2 million m3 of sand and gravel on the seafloor offshore of the river mouth. The total sediment budget during the first two years revealed that the vast majority (~ 90%) of the sediment released from the former reservoirs to the river passed through the fluvial system and was discharged to the coastal

  2. Linking Ah receptor mediated effects of sediments and impacts on fish to key pollutants in the Yangtze Three Gorges Reservoir, China - A comprehensive perspective.

    Science.gov (United States)

    Floehr, Tilman; Scholz-Starke, Björn; Xiao, Hongxia; Hercht, Hendrik; Wu, Lingling; Hou, Junli; Schmidt-Posthaus, Heike; Segner, Helmut; Kammann, Ulrike; Yuan, Xingzhong; Roß-Nickoll, Martina; Schäffer, Andreas; Hollert, Henner

    2015-12-15

    The Three Gorges Reservoir (TGR), created in consequence of the Yangtze River's impoundment by the Three Gorges Dam, faces numerous anthropogenic impacts that challenge its unique ecosystem. Organic pollutants, particularly aryl hydrocarbon receptor (AhR) agonists, have been widely detected in the Yangtze River, but only little research was yet done on AhR-mediated activities. Hence, in order to assess effects of organic pollution, with particular focus on AhR-mediated activities, several sites in the TGR area were examined applying the "triad approach". It combines chemical analysis, in vitro, in vivo and in situ investigations to a holistic assessment. Sediments and the benthic fish species Pelteobagrus vachellii were sampled in 2011/2012, respectively, to identify relevant endpoints. Sediment was tested in vitro with the ethoxyresorufin-O-deethylase (EROD) induction assay, and in vivo with the Fish Embryo Toxicity Test and Sediment Contact Assay with Danio rerio. Activities of phase I (EROD) and phase II (glutathione-S-transferase) biotransformation enzymes, pollutant metabolites and histopathological alterations were studied in situ in P. vachellii. EROD induction was tested in vitro and in situ to evaluate possible relationships. Two sites, near Chongqing and Kaixian city, were identified as regional hot-spots and further investigated in 2013. The sediments induced in the in vitro/in vivo bioassays AhR-mediated activities and embryotoxic/teratogenic effects - particularly on the cardiovascular system. These endpoints could be significantly correlated to each other and respective chemical data. However, particle-bound pollutants showed only low bioavailability. The in situ investigations suggested a rather poor condition of P. vachellii, with histopathological alterations in liver and excretory kidney. Fish from Chongqing city exhibited significant hepatic EROD induction and obvious parasitic infestations. The polycyclic aromatic hydrocarbon (PAH) metabolite 1

  3. Evaluation of virus removal efficiency of coagulation-sedimentation and rapid sand filtration processes in a drinking water treatment plant in Bangkok, Thailand.

    Science.gov (United States)

    Asami, Tatsuya; Katayama, Hiroyuki; Torrey, Jason Robert; Visvanathan, Chettiyappan; Furumai, Hiroaki

    2016-09-15

    In order to properly assess and manage the risk of infection by enteric viruses in tap water, virus removal efficiency should be evaluated quantitatively for individual processes in actual drinking water treatment plants (DWTPs); however, there have been only a few studies due to technical difficulties in quantifying low virus concentration in water samples. In this study, the removal efficiency of indigenous viruses was evaluated for coagulation-sedimentation (CS) and rapid sand filtration (RSF) processes in a DWTP in Bangkok, Thailand by measuring the concentration of viruses before and after treatment processes using real-time polymerase chain reaction (qPCR). Water samples were collected and concentrated from raw source water, after CS, and after RSF, and inhibitory substances in water samples were reduced by use of a hydrophobic resin (DAX-8). Pepper mild mottle virus (PMMoV) and JC polyomavirus (JC PyV) were found to be highly prevalent in raw waters, with concentrations of 10(2.88 ± 0.35) and 10(3.06 ± 0.42) copies/L (geometric mean ± S.D.), respectively. Step-wise removal efficiencies were calculated for individual processes, with some variation observed between wet and dry seasons. During the wet season, PMMoV was removed less by CS and more by RSF on average (0.40 log10 vs 1.26 log10, respectively), while the reverse was true for JC PyV (1.91 log10 vs 0.49 log10, respectively). Both viruses were removed similarly during the dry season, with CS removing the most virus (PMMoV, 1.61 log10 and 0.78 log10; JC PyV, 1.70 log10, and 0.59 log10; CS and RSF, respectively). These differences between seasons were potentially due to variations in raw water quality and the characteristics of the viruses themselves. These results suggest that PMMoV and JC PyV, which are more prevalent in environmental waters than the other enteric viruses evaluated in this study, could be useful in determining viral fate for the risk management of viruses in water treatment

  4. Trade-off analysis of discharge-desiltation-turbidity and ANN analysis on sedimentation of a combined reservoir-reach system under multi-phase and multi-layer conjunctive releasing operation

    Science.gov (United States)

    Huang, Chien-Lin; Hsu, Nien-Sheng; Wei, Chih-Chiang; Yao, Chun-Hao

    2017-10-01

    Multi-objective reservoir operation considering the trade-off of discharge-desiltation-turbidity during typhoons and sediment concentration (SC) simulation modeling are the vital components for sustainable reservoir management. The purposes of this study were (1) to analyze the multi-layer release trade-offs between reservoir desiltation and intake turbidity of downstream purification plants and thus propose a superior conjunctive operation strategy and (2) to develop ANFIS-based (adaptive network-based fuzzy inference system) and RTRLNN-based (real-time recurrent learning neural networks) substitute SC simulation models. To this end, this study proposed a methodology to develop (1) a series of multi-phase and multi-layer sediment-flood conjunctive release modes and (2) a specialized SC numerical model for a combined reservoir-reach system. The conjunctive release modes involve (1) an optimization model where the decision variables are multi-phase reduction/scaling ratios and the timings to generate a superior total release hydrograph for flood control (Phase I: phase prior to flood arrival, Phase II/III: phase prior to/subsequent to peak flow) and (2) a combination method with physical limitations regarding separation of the singular hydrograph into multi-layer release hydrographs for sediment control. This study employed the featured signals obtained from statistical quartiles/sediment duration curve in mesh segmentation, and an iterative optimization model with a sediment unit response matrix and corresponding geophysical-based acceleration factors, for efficient parameter calibration. This research applied the developed methodology to the Shihmen Reservoir basin in Taiwan. The trade-off analytical results using Typhoons Sinlaku and Jangmi as case examples revealed that owing to gravity current and re-suspension effects, Phase I + II can de-silt safely without violating the intake's turbidity limitation before reservoir discharge reaches 2238 m3/s; however

  5. Geochemical radioactive investigation of beach sands and stream sediments, using heavy minerals, trace elements and radon measurements, (Qerdaha sheet of the Syrian coast)

    International Nuclear Information System (INIS)

    Jubeli, Y.; Kattaa, B.; Al-Hilal, M.

    2000-05-01

    Reconnaissance geochemical radiometric survey of stream sediments resulting from the weathering of outcropped rocks in and around the study area was performed. This survey included heavy mineral sampling, trace and radioelements and radon measurements to evaluate the radioactivity of the source rocks and to understand the nature and distribution of the heavy minerals and trace elements in the study area. Several techniques were used to achieve these objectives. The results of heavy mineral geochemical survey show that the abundant minerals are iron oxides (magnetite, hematite, goehtite and limonite) pyroxene and olivine; less abundant minerals are apatite, ilmenite, garnet, barite, siderite and gloconite, while rare minerals are zircon and rutile. Amphibole is reported as an abundant mineral in sand dunes and is less abundant in samples located in the northern part of the study area. The amphibole seems to be derived from the ophiolitic complex north of the study area. Grain size analysis of heavy minerals revealed that the concentration of economic minerals such as zircon rutile and ilmenite increases with the decrease of the grain size. The microscopic study showed fragments and fossils of foraminifere mostly impregnated with heavy metals such as iron and manganese resulting from diagenetic metasomatism and replacement processes of. Fish teeth (< 2 mm) and oolite of iron were also noticed in most of the samples. The morphology of heavy mineral grains shows that most of the grains are angular to subangular suggesting that they were transported for short distance from their source rocks. Normally, phosphate pellets, gloconite and iron ooids are not considered since their original morphological features show clear roundness that attributed to their sedimentological origin, not to transportation factor. The source rock of most of the heavy mineral assemblage is the basalt. Apatite and gloconite are derived from the phosphorite and phosphatized limestone encountered

  6. Sedimentological Characterization of a Deepwater Methane Hydrate Reservoir in Green Canyon 955, Northern Gulf of Mexico

    Science.gov (United States)

    Meazell, K.; Flemings, P. B.

    2017-12-01

    Grain size is a controlling factor of hydrate saturation within a Pleistocene channel-levee system investigated by the UT-GOM2-1 expedition within the deepwater northern Gulf of Mexico. Laser diffraction and settling experiments conducted on sediments from 413-440 meters below the seafloor reveal the presence of two interbedded lithologic units, identified as a silty sand and a clayey silt, according Shepard's classification system. The sand-rich lithofacies has low density and high p-wave velocity, suggesting a high degree of hydrate saturation. Conversely, the clay and silt dominated lithofacies is characterized by a higher density and low p-wave velocity, suggesting low hydrate saturation. The sand-rich lithofacies is well-sorted and displays abundant ripple lamination, indicative of deposition within a high-energy environment. The clayey-silt is poorly-sorted and lacks sedimentary structures. The two lithofacies are interbedded throughout the reservoir unit; however, the relative abundance of the sand-rich lithofacies increases with depth, suggesting a potential decrease in flow energy or sediment flux over time, resulting in the most favorable reservoir properties near the base of the unit.

  7. Effect of water flux and sediment discharge of the Yangtze River on PAHs sedimentation in the estuary.

    Science.gov (United States)

    Li, Rufeng; Feng, Chenghong; Wang, Dongxin; He, Maozhi; Hu, Lijuan; Shen, Zhenyao

    2016-12-01

    Historical distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) and their carriers (i.e., organic matter and mineral particles) in the sediment cores of the Yangtze Estuary were investigated, with emphasis laid on the role of the Yangtze River. Grain size component of sediments (clay, silt, and sand) and organic carbon (black carbon and total organic carbon) in the sediment cores were markedly affected by water flux and sediment discharge of the Yangtze River. Qualitative and quantitative analysis results showed that sands and black carbon acted as the main carriers of PAHs. The sedimentation of two-ring to three-ring PAHs in the estuary had significant correlations with water flux and sediment discharge of the Yangtze River. The relative lower level of the four-ring and five-ring to six-ring PAHs concentrations appeared around the year 2003 and remained for the following several years. This time period accorded well with the water impoundment time of the Three Gorges Reservoir. The decreased level of two-ring to three-ring PAHs occurred in the year 1994, and the peak points around the year 2009 indicated that PAHs sedimentation in the estuary also had close relationship to severe drought and flood in the catchments. The findings presented in this paper could provide references for assessing the impacts of water flux and sediment discharge on the historical deposition of PAHs and their carriers in the Yangtze Estuary.

  8. Increasing Waterflood Reserves in the Wilmington Oil Field through Improved Reservoir Characterization and Reservoir Management

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, D.; Koerner, R.; Moos D.; Nguyen, J.; Phillips, C.; Tagbor, K.; Walker, S.

    1999-04-05

    This project used advanced reservoir characterization tools, including the pulsed acoustic cased-hole logging tool, geologic three-dimensional (3-D) modeling software, and commercially available reservoir management software to identify sands with remaining high oil saturation following waterflood. Production from the identified high oil saturated sands was stimulated by recompleting existing production and injection wells in these sands using conventional means as well as a short radius redrill candidate.

  9. OU3 sediment dating and sedimentation rates

    International Nuclear Information System (INIS)

    Blair, R.B.; Wolaver, H.A.; Burger, V.M.

    1994-01-01

    Environmental Technologies at Rocky Flats Environmental Technology Site (RFS) investigated the sediment history of Standley Lake, Great Western Reservoir, and Mower Reservoir using 137 Cs and 239,240 Pu global fall-out as dating indicators. These Colorado Front Range reservoirs have been the subject of study by various city, state and national agencies due to suspected Department of Energy Rocky Flats Plant impacts. We performed sediment dating as part of the RCRA Facility Investigation/Remedial Investigation Report for Operable Unit 3. A sediment chronology profile assists scientist in determining the year of sedimentation for a particular peak concentration of contaminants. Radioisotope sediment dating for the three reservoirs indicated sedimentation rates of 0.7 to 0.8 in./yr. for Standley Lake (SL), 0.9 in./yr. for Great Western Reservoir (GWR), and 0.3 in./yr. in Mower Reservoir (MR). RFS sediment dating for Operable Unit 3 compared favorably with the Hardy, Livingston, Burke, and Volchok Standley Lake study. This report describes the cesium/plutonium sediment dating method, estimates sedimentation rates for Operable Unit 3 reservoirs, and compares these results to previous investigations

  10. Evaluation and distribution of metals, trace elements and rare earths in sediments profiles of Promissão Reservoir, Sao Paulo state, Brazil, by INAA

    International Nuclear Information System (INIS)

    Angelini, Matheus; Rocha, Flavio R.; Fávaro, Deborah I.T.; Franklin, Robson L.

    2017-01-01

    The concentration of elements at two points in the reservoir (1 and 3) was evaluated. Two profiles of fractionated sediments were collected in the field every 2.5 cm, generating 14 and 20 fractions, respectively, according to their depths (35 and 50 cm). The concentrations of the elements: As, Ba, Br, Ca, Co, Cr, Cs, Fe, Hf, K, Na, Rb, Sb, Sc, Ta, Th, U, Zn and the rare earth elements (Ce, Eu, Gd, La, Lu, Nd, Sm, Tb and Yb) were determined using the technique of Instrumental Neutron Activation Analysis (INAA). The validation of the methodology was done through the analysis of certified reference materials. The values of the North American Shale Composite (NASC) were used as reference values for calculation of Enrichment Factor (FE) and Geoacumulation Index (IGeo), tools used to evaluate pollution levels. The concentration of the As, Cr and Zn elements was also compared with the Guideline values TEL (Treshold Effect Level) and PEL (Probable Effect Level), values that provide concentration ranges for these elements indicating the presence or not of probable effects in aquatic biota from these concentrations

  11. 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.

  12. Estimation of Bank Erosion Due To Reservoir Operation in Cascade (Case Study: Citarum Cascade Reservoir

    Directory of Open Access Journals (Sweden)

    Sri Legowo

    2009-11-01

    Full Text Available Sedimentation is such a crucial issue to be noted once the accumulated sediment begins to fill the reservoir dead storage, this will then influence the long-term reservoir operation. The sediment accumulated requires a serious attention for it may influence the storage capacity and other reservoir management of activities. The continuous inflow of sediment to the reservoir will decrease the capacity of reservoir storage, the reservoir value in use, and the useful age of reservoir. Because of that, the rate of the sediment needs to be delayed as possible. In this research, the delay of the sediment rate is considered based on the rate of flow of landslide of the reservoir slope. The rate of flow of the sliding slope can be minimized by way of each reservoir autonomous efforts. This effort can be performed through; the regulation of fluctuating rate of reservoir surface current that does not cause suddenly drawdown and upraising as well. The research model is compiled using the searching technique of Non Linear Programming (NLP.The rate of bank erosion for the reservoir variates from 0.0009 to 0.0048 MCM/year, which is no sigrificant value to threaten the life time of reservoir.Mean while the rate of watershed sediment has a significant value, i.e: 3,02 MCM/year for Saguling that causes to fullfill the storage capacity in 40 next years (from years 2008.

  13. 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...

  14. Highstand shelf fans: The role of buoyancy reversal in the deposition of a new type of shelf sand body

    Science.gov (United States)

    Steel, Elisabeth; Simms, Alexander R.; Warrick, Jonathan; Yokoyama, Yusuke

    2016-01-01

    Although sea-level highstands are typically associated with sediment-starved continental shelves, high sea level does not hinder major river floods. Turbidity currents generated by plunging of sediment-laden rivers at the fluvial-marine interface, known as hyperpycnal flows, allow for cross-shelf transport of suspended sand beyond the coastline. Hyperpycnal flows in southern California have deposited six subaqueous fans on the shelf of the northern Santa Barbara Channel in the Holocene. Using eight cores and nine grab samples, we describe the deposits, age, and stratigraphic architecture of two fans in the Santa Barbara Channel. Fan lobes have up to 3 m of relief and are composed of multiple hyperpycnite beds ∼5 cm to 40 cm thick. Deposit architecture and geometry suggest the hyperpycnal flows became positively buoyant and lifted off the seabed, resulting in well-sorted, structureless, elongate sand lobes. Contrary to conventional sequence stratigraphic models, the presence of these features on the continental shelf suggests that active-margin shelves may locally develop high-quality reservoir sand bodies during sea-level highstands, and that such shelves need not be solely the site of sediment bypass. These deposits may provide a Quaternary analogue to many well-sorted sand bodies in the rock record that are interpreted as turbidites but lack typical Bouma-type features.

  15. Modelling offshore sand wave evolution

    NARCIS (Netherlands)

    Nemeth, Attila; Hulscher, Suzanne J.M.H.; van Damme, Rudolf M.J.

    2007-01-01

    We present a two-dimensional vertical (2DV) flow and morphological numerical model describing the behaviour of offshore sand waves. The model contains the 2DV shallow water equations, with a free water surface and a general bed load formula. The water movement is coupled to the sediment transport

  16. Effective control of modified palygorskite to NH4+-N release from sediment.

    Science.gov (United States)

    Chen, Lei; Zheng, Tianyuan; Zhang, Junjie; Liu, Jie; Zheng, Xilai

    2014-01-01

    Sediment capping is an in situ treatment technology that can effectively restrain nutrient and pollutant release from the sediment in lakes and reservoirs. Research on sediment capping has focused on the search for effective, non-polluting and affordable capping materials. The efficiency and mechanism of sediment capping with modified palygorskite in preventing sediment ammonia nitrogen (NH4+-N) release to surface water were investigated through a series of batch and sediment capping experiments. Purified palygorskite and different types of modified palygorskite (i.e. heated, acid-modified and NaCI-modified palygorskite) were used in this investigation. Factors affecting control efficiency, including the temperature, thickness and grain size of the capping layer, were also analysed. The batch tests showed that the adsorption of NH4+-N on modified palygorskite achieved an equilibration in the initial 45 min, and the adsorption isotherm followed the Freundlich equation. Sediment capping experiments showed that compared with non-capped condition, covering the sediment with modified palygorskite and sand both inhibited NH4+-N release to the overlying water. Given its excellent chemical stability and strong adsorption, heated palygorskite, which has a NH4+-N release inhibition ratio of 41.3%, is a more effective sediment capping material compared with sand. The controlling effectiveness of the modified palygorskite increases with thicker capping layer, lower temperature and smaller grain size of the capping material.

  17. Impacts of Mechanical Macrophyte Removal Devices on Sediment Scouring in Littoral Habitats: II. Experimental Operation in the Littoral Zone of Eau Galle Reservoir, Wisconsin

    National Research Council Canada - National Science Library

    James, William F; Wright, David I; Barko, John W; Eakin, Harry L

    2006-01-01

    ... in Eau Galle Reservoir, Wisconsin. Mechanical macrophyte removal devices are an attractive, low-cost means of removing macrophytes in specific areas without herbicides or repeated mechanical harvesting...

  18. Nuclear Well Log Properties of Natural Gas Hydrate Reservoirs

    Science.gov (United States)

    Burchwell, A.; Cook, A.

    2015-12-01

    Characterizing gas hydrate in a reservoir typically involves a full suite of geophysical well logs. The most common method involves using resistivity measurements to quantify the decrease in electrically conductive water when replaced with gas hydrate. Compressional velocity measurements are also used because the gas hydrate significantly strengthens the moduli of the sediment. At many gas hydrate sites, nuclear well logs, which include the photoelectric effect, formation sigma, carbon/oxygen ratio and neutron porosity, are also collected but often not used. In fact, the nuclear response of a gas hydrate reservoir is not known. In this research we will focus on the nuclear log response in gas hydrate reservoirs at the Mallik Field at the Mackenzie Delta, Northwest Territories, Canada, and the Gas Hydrate Joint Industry Project Leg 2 sites in the northern Gulf of Mexico. Nuclear logs may add increased robustness to the investigation into the properties of gas hydrates and some types of logs may offer an opportunity to distinguish between gas hydrate and permafrost. For example, a true formation sigma log measures the thermal neutron capture cross section of a formation and pore constituents; it is especially sensitive to hydrogen and chlorine in the pore space. Chlorine has a high absorption potential, and is used to determine the amount of saline water within pore spaces. Gas hydrate offers a difference in elemental composition compared to water-saturated intervals. Thus, in permafrost areas, the carbon/oxygen ratio may vary between gas hydrate and permafrost, due to the increase of carbon in gas hydrate accumulations. At the Mallik site, we observe a hydrate-bearing sand (1085-1107 m) above a water-bearing sand (1107-1140 m), which was confirmed through core samples and mud gas analysis. We observe a decrease in the photoelectric absorption of ~0.5 barnes/e-, as well as an increase in the formation sigma readings of ~5 capture units in the water-bearing sand as

  19. Mineral compositions and sources of the riverbed sediment in the desert channel of Yellow River.

    Science.gov (United States)

    Jia, Xiaopeng; Wang, Haibing

    2011-02-01

    The Yellow River flows through an extensive, aeolian desert area and extends from Xiaheyan, Ningxia Province, to Toudaoguai, Inner Mongolia Province, with a total length of 1,000 km. Due to the construction and operation of large reservoirs in the upstream of the Yellow River, most water and sediment from upstream were stored in these reservoirs, which leads to the declining flow in the desert channel that has no capability to scour large amount of input of desert sands from the desert regions. By analyzing and comparing the spatial distribution of weight percent of mineral compositions between sediment sources and riverbed sediment of the main tributaries and the desert channel of the Yellow River, we concluded that the coarse sediment deposited in the desert channel of the Yellow River were mostly controlled by the local sediment sources. The analyzed results of the Quartz-Feldspar-Mica (QFM) triangular diagram and the R-factor models of the coarse sediment in the Gansu reach and the desert channel of the Yellow River further confirm that the Ningxia Hedong desert and the Inner Mongolian Wulanbuhe and Kubuqi deserts are the main provenances of the coarse sediment in the desert channel of the Yellow River. Due to the higher fluidity of the fine sediment, they are mainly contributed by the local sediment sources and the tributaries that originated from the loess area of the upper reach of the Yellow River.

  20. Seasonal changing sand waves and the effect of surface waves

    NARCIS (Netherlands)

    Sterlini, Fenneke; van Dijk, Thaiënne A.G.P.; IJzer, Steven; Hulscher, Suzanne; Schüttrumpf, Holger; Tomasicchio, Guiseppe Roberto

    2012-01-01

    Sand waves are wavelike subaqueous sediment structures that exist in large areas in shelf seas. Due to their characteristics sand waves can severely affect human offshore activities, such as navigation. This makes it important to understand the physical processes that shape and change sand waves. In

  1. 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.

  2. Organic matter content and particle size modifications in mangrove sediments as responses to sea level rise.

    Science.gov (United States)

    Sanders, Christian J; Smoak, Joseph M; Waters, Mathew N; Sanders, Luciana M; Brandini, Nilva; Patchineelam, Sambasiva R

    2012-06-01

    Mangroves sediments contain large reservoirs of organic material (OM) as mangrove ecosystems produce large quantities and rapidly burial OM. Sediment accumulation rates of approximately 2.0 mm year(-1), based on (210)Pb(ex) dating, were estimated at the margin of two well-developed mangrove forest in southern Brazil. Regional data point to a relative sea level (RSL) rise of up to ∼4.0 mm year(-1). This RSL rise in turn, may directly influence the origin and quantity of organic matter (OM) deposited along mangrove sediments. Lithostratigraphic changes show that sand deposition is replacing the mud (<63 μm) fraction and OM content is decreasing in successively younger sediments. Sediment accumulation in coastal areas that are not keeping pace with sea level rise is potentially conducive to the observed shifts in particle size and OM content. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Laboratory isotopic behaviour (2H, 18O) of sediments pore water during evaporation

    International Nuclear Information System (INIS)

    Ciolzyk, A.; Bariac, T.; Klamecki, A.; Jusserand, C.

    1987-01-01

    Two bare sediments (sand and loam) wetted with water of known isotopic composition have been subjected to evaporation in laboratory conditions. An attempt of application of classical isotopic evaporation models for free waters with reducing reservoir has been made, the better fit implies: a)laminar conditions of the atmosphere in the sediment under evaporation; b) a similar isotopic composition of water vapor as the isotopic composition of the water vapor of the external atmosphere. Variation of ε K and δ V H implies a better knowledge of the complex mechanisms of the atmosphere behaviour in the pore path of porous media under evaporation [fr

  4. 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.

  5. Sand control systems used in completing wells

    Directory of Open Access Journals (Sweden)

    Gabriel Wittenberger

    2005-12-01

    Full Text Available Expandable Tubular Technology is transforming the face of well completion and construction. This technology provides: a substantially higher hydrocarbon production rates from the reservoir, a reduced well drilling and construction costs, new possibilities for previously unreachable or uneconomic reservoirs, and step a change towards the single diameter well. ESS (Expandable Sand Screen has an unrivalled performance worldwide for delivering a reliable sand control in a wide range of applications. Well costs typically cut by over 20 %, and the productivity increases up to 70 %.

  6. Fortescue reservoir development and reservoir studies

    Energy Technology Data Exchange (ETDEWEB)

    Henzell, S.T.; Hicks, G.J.; Horden, M.J.; Irrgang, H.R.; Janssen, E.J.; Kable, C.W.; Mitchell, R.A.H.; Morrell, N.W.; Palmer, I.D.; Seage, N.W.

    1985-03-01

    The Fortescue field in the Gippsland Basin, offshore southeastern Australia is being developed from two platforms (Fortescue A and Cobia A) by Esso Australia Ltd. (operator) and BHP Petroleum. The Fortescue reservoir is a stratigraphic trap at the top of the Latrobe Group of sediments. It overlies the western flank of the Halibut and Cobia fields and is separated from them by a non-net sequence of shales and coals which form a hydraulic barrier between the two systems. Development drilling into the Fortescue reservoir commenced in April 1983 with production coming onstream in May 1983. Fortescue, with booked reserves of 44 stock tank gigalitres (280 million stock tank barrels) of 43/sup 0/ API oil, is the seventh major oil reservoir to be developed in the offshore Gippsland Basin by Esso/BHP. In mid-1984, after drilling a total of 20 exploration and development wells, and after approximately one year of production, a detailed three-dimensional, two-phase reservoir simulation study was performed to examine the recovery efficiency, drainage patterns, pressure performance and production rate potential of the reservoir. The model was validated by history matching an extensive suite of Repeat Formation Test (RFT) pressure data. The results confirmed the reserves basis, and demonstrated that the ultimate oil recovery from the reservoir is not sensitive to production rate. This result is consistent with studies on other high quality Latrobe Group reservoirs in the Gippsland Basin which contain undersaturated crudes and receive very strong water drive from the Basin-wide aquifer system. With the development of the simulation model during the development phase, it has been possible to more accurately define the optimal well pattern for the remainder of the development.

  7. Study of the relation between soil use, vegetation coverage, and the discharge of sediments from artificial reservoirs using MSS/LANDSAT images. Example: The Tres Marias reservoir and its supply basin

    Science.gov (United States)

    Dejesusparada, N. (Principal Investigator); Sausen, T. M.

    1981-01-01

    The land use and types of vegetation in the region of the upper Sao Francisco River, Brazil, are identified. This region comprises the supply basin of the Tres Marias reservoir. Imagery from channels 5 and 7 of the LANDSAT multispectral band scanner during wet and rainy seasons and ground truth data were employed to characterize and map the vegetation, land use, and sedimentary discharges from the reservoir. Agricultural and reforested lands, meadows, and forests are identified. Changes in land use due to human activity are demonstrated.

  8. Morphologic Response and Sediment Redistribution of the Beach and Nearshore Sand Bars due to Extratropical and Tropical Storm Forcing: a Spatial and Temporal Analysis

    Science.gov (United States)

    Miselis, J. L.; McNinch, J. E.

    2005-05-01

    Shore-oblique bars and associated exposures of an underlying geologic stratum in the nearshore have been documented along the US East Coast and have been linked to shoreline erosional hotspots. While earlier studies acknowledged that the bedforms responded to extratropical and tropical storms, neither quantified the extent of sediment redistribution after the events. An approach that encompasses actual volume measurements across the nearshore-beach down to a non-sandy stratum and quantifies the response of the beach and the nearshore to the same hydrodynamic forcing will enable a better understanding of the exchange of sediment between the two regions. Total nearshore sediment volume has been shown to be a first-order contributor to the behavior of the shoreline. This volumetric approach is employed in the analysis of morphological changes and the redistribution of sediment in the nearshore and beach following storms. A regional survey from 2002 provides the initial, fair-weather morphologic state of the nearshore (1.5-15m water depth) spanning 40 km of the North Carolina Outer Banks. Four small-scale surveys were conducted in subsequent years, focusing on four 1-km2 regions within the initial 2002 survey area. The smaller regions were selected on the basis of the morphological state observed during the 2002 survey and historical shoreline behavior. Data were collected in March 2003 following a Northeaster; in May 2003 following an extended period of fair weather conditions; in November 2003 following Hurricane Isabel; and finally, in June 2004 after another period of fair weather. A swath bathymetry system was used to collect bathymetry and side scan sonar (acoustic backscatter) and a high-resolution chirp sub-bottom profiler imaged the shallow sub-surface geology of the nearshore. In addition, RTK-GPS was used to map the sub-aerial beach at each 1-km2 site from the toe of the dune to the water line for the May 2003, November 2003, and June 2004 sampling periods

  9. Maqalika Reservoir: utilisation and sustainability of Maqalika Reservoir as a source of potable water supply for Maseru in Lesotho

    CSIR Research Space (South Africa)

    Letsie, M

    2008-07-01

    Full Text Available The storage of water in the Maqalika reservoir is gradually decreasing as sediment, carried by the natural catchment run-off, accumulates in the reservoir. Moreover, water pumped into the reservoir from the Caledon River (which is heavily sedimented...

  10. Evaluating the importance of surface soil contributions to reservoir sediment in alpine environments: a combined modelling and fingerprinting approach in the Posets-Maladeta Natural Park

    Science.gov (United States)

    Palazón, L.; Gaspar, L.; Latorre, B.; Blake, W. H.; Navas, A.

    2014-09-01

    Soil in alpine environments plays a key role in the development of ecosystem services and in order to maintain and preserve this important resource, information is required on processes that lead to soil erosion. Similar to other mountain alpine environments, the Benasque catchment is characterised by temperatures below freezing that can last from November to April, intense rainfall events, typically in spring and autumn, and rugged topography which makes assessment of erosion challenging. Indirect approaches to soil erosion assessment, such as combined model approaches, offer an opportunity to evaluate soil erosion in such areas. In this study (i) the SWAT (Soil and Water Assessment Tool) hydrological and erosion model and (ii) sediment fingerprinting procedures were used in parallel to assess the viability of a combined modelling and tracing approach to evaluate soil erosion processes in the area of the Posets-Maladeta Natural Park (central Spanish Pyrenees). Soil erosion rates and sediment contribution of potential sediment sources defined by soil type (Kastanozems/Phaeozems; Fluvisols and Cambisols) were assessed. The SWAT model suggested that, with the highest specific sediment yields, Cambisols are the main source of sediment in the Benasque catchment and Phaeozems and Fluvisols were identified as the lowest sediment contributors. Spring and winter model runs gave the highest and lowest specific sediment yield, respectively. In contrast, sediment fingerprinting analysis identified Fluvisols, which dominate the riparian zone, as the main sediment source at the time of sampling. This indicates the importance of connectivity as well as potential differences in the source dynamic of material in storage versus that transported efficiently from the system at times of high flow. The combined approach enabled us to better understand soil erosion processes in the Benasque alpine catchment, wherein SWAT identified areas of potential high sediment yield in large flood

  11. Assessment of metal concentrations in sediment samples from Billings Reservoir, Rio Grande tributary, Sao Paulo, Brazil; Avaliacao da concentracao de metais em amostras de sedimento do Reservatorio Billings, Braco Rio Grande, Sao Paulo, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Bostelmann, Eleine

    2006-07-01

    The present study chemically characterized sediment samples from the Billings reservoir, Rio Grande tributary, in the Metropolitan region of Sao Paulo, by determining metal concentration and other elements of interest. The chosen chemical parameters for this characterization were Aluminum, Arsenic, Barium, Cadmium, Copper, Chromium, Iron, Lead, Manganese, Mercury, Nickel, Selenium and Zinco. These parameters are also used in the water quality index, with the exception of Selenium. The concentrations were determined through different analytical techniques such as atomic absorption spectrometry (FAAS, GFAAS and CVAAS), optical emission spectrometry (ICP OES) and neutron activation analysis. These analytical methodologies were assessed for precision, accuracy and detection and/or quantification limits for the sediment elements in question. Advantages and disadvantages of each technique for each element and its concentration were also discussed. From these assessments the most adequate technique was selected for the routine analysis of sediment samples for each element concentration determination. This assessment verified also that digestion in a closed microwave system with nitric acid is efficient for the evaluation of extracted metals of environmental interest. The analytical techniques chosen were equally efficient for metals determination. In the case of Cd and Pb, the FAAS technique was selected due to better results than ICP OES, as it does not present matrix interference. The concentration values obtained for metals As, Cd, Cu, Cr, Hg, Ni, Pb and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) TEL and PEL values. (author)

  12. Mineral sands

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    This paper presents an outlook of the Australian mineral sand industry and covers the major operators. It is shown that conscious of an environmentally minded public, the Australian miners have led the way in the rehabilitation of mined areas. Moreover the advanced ceramic industry is generating exciting new perspectives for zircon producers and there is a noticeable growth in the electronic market for rare earths, but in long term the success may depend as much on environmental management and communication skills as on mining and processing skills

  13. Geothermal prospection in the Greater Geneva Basin (Switzerland and France). Impact of diagenesis on reservoir properties of the Upper Jurassic carbonate sediments

    Science.gov (United States)

    Makhloufi, Yasin; Rusillon, Elme; Brentini, Maud; Clerc, Nicolas; Meyer, Michel; Samankassou, Elias

    2017-04-01

    Diagenesis of carbonate rocks is known to affect the petrophysical properties (porosity, permeability) of the host rock. Assessing the diagenetic history of the rock is thus essential when evaluating any reservoir exploitation project. The Canton of Geneva (Switzerland) is currently exploring the opportunities for geothermal energy exploitation in the Great Geneva Basin (GGB) sub-surface. In this context, a structural analysis of the basin (Clerc et al., 2016) associated with reservoir appraisal (Brentini et al., 2017) and rock-typing of reservoir bodies of potential interest were conducted (Rusillon et al., 2017). Other geothermal exploitation projects elsewhere (e.g. Bavaria, south Germany, Paris Basin, France) showed that dolomitized carbonate rocks have good reservoir properties and are suitable for geothermal energy production. The objectives of this work are to (1) describe and characterize the dolomitized bodies in the GGB and especially their diagenetic history and (2) quantify the reservoir properties of those bodies (porosity, permeability). Currently, our study focuses on the Upper Jurassic sedimentary bodies of the GGB. Field and well data show that the dolomitization is not ubiquitous in the GGB. Results from the petrographical analyses of the Kimmeridgian cores (Humilly-2) and of field analogues (Jura, Saleve and Vuache mountains) display complex diagenetic histories, dependent of the study sites. The paragenesis exhibits several stages of interparticular calcite cementation as well as different stages of dolomitization and/or dedolomitization. Those processes seem to follow constrained path of fluid migrations through burial, faulting or exhumation during the basin's history. These complex diagenetic histories affected the petrophysical and microstructural properties via porogenesis (conservation of initial porosity, moldic porosity) and/or poronecrosis events. The best reservoir properties appear to be recorded in patch reef and peri

  14. Aeolian sedimentation in the middle buntsandstein in the eifel north-south depression zone: Summary of the variability of sedimentary processes in a buntsandstein erg as a base for evaluation of the mutual relationships between aeolian sand seas and fluvial river systems in the mid-european buntsandstein

    Science.gov (United States)

    Mader, Detlef

    The spectrum of aeolian depositional subenvironments in the upper Middle Buntsandstein Karlstal-Schichten sequence in the Eifel North-South-zone at the western margin of the Mid-European Triassic Basin comprises trains of larger and higher narrowly-spaced dunes in sand seas, isolated smaller and lower widely-spaced dunes in floodplains and interdune playas, dry interdune sheet sands, damp interdune adhesive sandflats, wet interdune playa lakes, rainfall runoff watercourses and ephemeral channels cutting through the dune belt, and deflation gravel lag veneers. Distinction of aeolian and fluvial sediments within the succession of closely intertonguing wind- and water-laid deposits is possible by independent analysis of the conventional criteria and the more modern stratification styles. Thick cross-bedded aeolian sand sequences originate as barchanoid-type dunes which accumulate and migrate in the regime of narrow to wide unimodal southeasterly to southwesterly trade winds in low northern palaeolatitude in summer when the intertropical convergence zone is shifted to the north. The predominantly transverse-ridge dunes accrete mainly by grainfall and subcritical climbing of wind ripples, subordinately also by grainflow interfingering with grainfall. Horizontal-laminated aeolian sands form as sand sheets in dry interdune playas by subcritical migration of wind ripple trains, rarely also by plane bed accretion. Thin cross-bedded dune sands or horizontal-laminated aeolian sands capping fluvial cyclothems originate by deflation of emerged alluvial bar sands during low-water stages and subsequent accumulation of the winnowed sand as widely-spaced dunelets or chains of wind ripples in desiccated parts of the adjoining floodplain. The aeolian sand layers at the base of lacustrine cyclothems record migration of isolated little dunes across the dry playa floor at the beginning of a wetting-upwards cyclothem, with the sand deriving from deflation of fluvial incursions or

  15. Mathematical and field analysis of longitudinal reservoir infill

    Science.gov (United States)

    Ke, W. T.; Capart, H.

    2016-12-01

    In reservoirs, severe problems are caused by infilled sediment deposits. In long term, the sediment accumulation reduces the capacity of reservoir storage and flood control benefits. In the short term, the sediment deposits influence the intakes of water-supply and hydroelectricity generation. For the management of reservoir, it is important to understand the deposition process and then to predict the sedimentation in reservoir. To investigate the behaviors of sediment deposits, we propose a one-dimensional simplified theory derived by the Exner equation to predict the longitudinal sedimentation distribution in idealized reservoirs. The theory models the reservoir infill geomorphic actions for three scenarios: delta progradation, near-dam bottom deposition, and final infill. These yield three kinds of self-similar analytical solutions for the reservoir bed profiles, under different boundary conditions. Three analytical solutions are composed by error function, complementary error function, and imaginary error function, respectively. The theory is also computed by finite volume method to test the analytical solutions. The theoretical and numerical predictions are in good agreement with one-dimensional small-scale laboratory experiment. As the theory is simple to apply with analytical solutions and numerical computation, we propose some applications to simulate the long-profile evolution of field reservoirs and focus on the infill sediment deposit volume resulting the uplift of near-dam bottom elevation. These field reservoirs introduced here are Wushe Reservoir, Tsengwen Reservoir, Mudan Reservoir in Taiwan, Lago Dos Bocas in Puerto Rico, and Sakuma Dam in Japan.

  16. Mixed response in bacterial and biochemical variables to simulated sand mining in placer-rich beach sediments, Ratnagiri, West coast of India.

    Science.gov (United States)

    Fernandes, Christabelle E G; Das, Anindita; Nath, B N; Faria, Daphne G; Loka Bharathi, P A

    2012-05-01

    We investigated the influence on bacterial community and biochemical variables through mechanical disturbance of sediment-akin to small-scale mining in Kalbadevi beach, Ratnagiri, a placer-rich beach ecosystem which is a potential mining site. Changes were investigated by comparing three periods, namely phase I before disturbance, phase II just after disturbance, and phase III 24 h after disturbance as the bacterial generation time is ≤7 h. Cores from dune, berm, high-, mid-, and low-tide were examined for changes in distribution of total bacterial abundance, total direct viability (counts under aerobic and anaerobic conditions), culturability and biochemical parameters up to 40 cm depth. Results showed that bacterial abundance decreased by an order from 10(6) cells g(-1) sediment, while, viability reduced marginally. Culturability on different-strength nutrient broth increased by 155% during phase II. Changes in sedimentary proteins, carbohydrates, and lipids were marked at berm and dune and masked at other levels by tidal influence. Sedimentary ATP reduced drastically. During phase III, Pearson's correlation between these variables evolved from non-significant to significant level. Thus, simulated disturbance had a mixed effect on bacterial and biochemical variables of the sediments. It had a negative impact on bacterial abundance, viability and ATP but positive impact on culturability. Viability, culturability, and ATP could act as important indicators reflecting the disturbance in the system at short time intervals. Culturability, which improved by an order, could perhaps be a fraction that contributes to restoration of the system at bacterial level. This baseline information about the potential mining site could help in developing rational approach towards sustainable harnessing of resources with minimum damage to the ecosystem.

  17. Reservoir management

    International Nuclear Information System (INIS)

    Satter, A.; Varnon, J.E.; Hoang, M.T.

    1992-01-01

    A reservoir's life begins with exploration leading to discovery followed by delineation of the reservoir, development of the field, production by primary, secondary and tertiary means, and finally to abandonment. Sound reservoir management is the key to maximizing economic operation of the reservoir throughout its entire life. Technological advances and rapidly increasing computer power are providing tools to better manage reservoirs and are increasing the gap between good and neural reservoir management. The modern reservoir management process involves goal setting, planning, implementing, monitoring, evaluating, and revising plans. Setting a reservoir management strategy requires knowledge of the reservoir, availability of technology, and knowledge of the business, political, and environmental climate. Formulating a comprehensive management plan involves depletion and development strategies, data acquisition and analyses, geological and numerical model studies, production and reserves forecasts, facilities requirements, economic optimization, and management approval. This paper provides management, engineers, geologists, geophysicists, and field operations staff with a better understanding of the practical approach to reservoir management using a multidisciplinary, integrated team approach

  18. Reservoir management

    International Nuclear Information System (INIS)

    Satter, A.; Varnon, J.E.; Hoang, M.T.

    1992-01-01

    A reservoir's life begins with exploration leading to discovery followed by delineation of the reservoir, development of the field, production by primary, secondary and tertiary means, and finally to abandonment. Sound reservoir management is the key to maximizing economic operation of the reservoir throughout its entire life. Technological advances and rapidly increasing computer power are providing tools to better manage reservoirs and are increasing the gap between good and neutral reservoir management. The modern reservoir management process involves goal setting, planning, implementing, monitoring, evaluating, and revising plans. Setting a reservoir management strategy requires knowledge of the reservoir, availability of technology, and knowledge of the business, political, and environmental climate. Formulating a comprehensive management plan involves depletion and development strategies, data acquisition and analyses, geological and numerical model studies, production and reserves forecasts, facilities requirements, economic optimization, and management approval. This paper provides management, engineers geologists, geophysicists, and field operations staff with a better understanding of the practical approach to reservoir management using a multidisciplinary, integrated team approach

  19. The pollution of the 'iron gate' reservoir

    International Nuclear Information System (INIS)

    Babic-Mladenovic, M.; Varga, S; Popovic, L.; Damjanovic, M.

    2002-01-01

    The paper presents the characteristics of the Iron Gate I (the Djerdap) Water Power and Navigational System, one of the largest in Europe (completed in 1972 by joint efforts of Yugoslavia and Romania). In this paper the attention is devoted to review of the sediment monitoring program and impacts of reservoir sedimentation, as well as to the investigations of water and sediment quality. Special consideration is paid to the issue of sediment pollution research needs. Namely, the hot spot of the 'Iron Gate' sedimentation represents a scarcely known pollution of sediment deposits. The present pollution probably is considerable, since the 'Iron Gate' reservoir drains about 577000 km 2 , with over 80 million inhabitants, and developed municipal and industrial infrastructure. Therefore, in the thirty-year reservoir life various types of sediment-bound pollutants entered and deposited within it. Especially severe incidents happened during 1999 (as a result of NATO bombing campaign) and 2000 (two accidental pollutions in the Tisza river catchment). The study of the 'Iron Gate' reservoir pollution should be prepared in order to enlighten the present state of reservoir sedimentation and pollution. The main objectives of the study are to enhance the government and public awareness of the present environmental state of the 'Iron Gate' reservoir and to serve as a baseline for all future actions. (author)

  20. Evolution of radioactive dose rates in fresh sediment deposits along coastal rivers draining Fukushima contamination plume.

    Science.gov (United States)

    Evrard, Olivier; Chartin, Caroline; Onda, Yuichi; Patin, Jeremy; Lepage, Hugo; Lefèvre, Irène; Ayrault, Sophie; Ottlé, Catherine; Bonté, Philippe

    2013-10-29

    Measurement of radioactive dose rates in fine sediment that has recently deposited on channel bed-sand provides a solution to address the lack of continuous river monitoring in Fukushima Prefecture after Fukushima Dai-ichi nuclear power plant (FDNPP) accident. We show that coastal rivers of Eastern Fukushima Prefecture were rapidly supplied with sediment contaminated by radionuclides originating from inland mountain ranges, and that this contaminated material was partly exported by typhoons to the coastal plains as soon as by November 2011. This export was amplified during snowmelt and typhoons in 2012. In 2013, contamination levels measured in sediment found in the upper parts of the catchments were almost systematically lower than the ones measured in nearby soils, whereas their contamination was higher in the coastal plains. We thereby suggest that storage of contaminated sediment in reservoirs and in coastal sections of the river channels now represents the most crucial issue.

  1. Survey of Potential Hanford Site Contaminants in the Upper Sediment for the Reservoirs at McNary, John Day, The Dalles, and Bonneville Dams, 2003

    Energy Technology Data Exchange (ETDEWEB)

    Patton, Gregory W.; Priddy, M; Yokel, Jerel W.; Delistraty, Damon A.; Stoops, Thomas M.

    2005-02-01

    This report presents the results from a multi-agency cooperative environmental surveillance study. of the study looked at sediment from the pools upstream from dams on the Columbia River that are downstream from Hanford Site operations. The radiological and chemical conditions existing in the upper-level sediment found in the pools upstream from McNary Dam, John Day Dam, The Dalles Lock and Dam, and Bonneville Dam were evaluated. This study also evaluated beach sediment where available. Water samples were collected at McNary Dam to further evaluate potential Hanford contaminants in the lower Columbia River. Samples were analyzed for radionuclides, chemicals, and physical parameters. Results from this study were compared to background values from sediment and water samples collect from the pool upstream of Priest Rapids Dam (upstream of the Hanford Site) by the Hanford Site Surface Environmental Surveillance Project.

  2. Assessment of Land Use Change and Sedimentation Modelling on Environmental Health in Tropical River

    International Nuclear Information System (INIS)

    Mohd Ekhwan Toriman; Mohd Ekhwan Toriman; Mohd Khairul Amri Kamarudin; Mohd Khairul Amri Kamarudin; Sansena, T.; Bhaktikuld, K.; Roslan Umar; Asyaari Muhamad; Nor Azlina Abd Aziz; Nur Hishaam Sulaiman

    2015-01-01

    Sediments are defined as the organic and inorganic materials or solid fragments derived from the weathering processes of sand, pebbles, silt, mud and loess. The objective of this research is to forecast sediment volume in the Lam Phra Phloeng reservoir by using the Neuro-genetic Optimizer model to calculate the sediment volume from runoff, rainfall, and sediment volume data. The results from satellite imagery interpretation elucidated that from 2002 to 2005, forest area decreased approximately 50,220 km"2 or 36 %, and was converted to agricultural land. By applying the USLE equation, the soil erosion area was found to increase approximately 185,341 tons/ year between 2002 and 2005. This result illustrated that the impact of land use change greatly increased sedimentation volume. In applying the Neuro-genetic Optimizer model, the learning rate and momentum of this model was 0.9 and 0.1, respectively, and the initial weight value was ± 3. The model forecasted the annual sediment volume in the Lam Phra Phloeng reservoir in 2005 to be 49,855 tons with R"2 equals to 0.9994. The regression model, on the other hand, forecasted the sediment volume using the equation Y=198.48 x 1.1783 with R"2 equals to 0.9974, and the annual sediment volume was estimated to be 45,346 tons. The actual sediment volume in the reservoir in 2005 was obtained from The Royal Irrigation Department, which was found to be 48,697 tons. (author)

  3. Count rate balance method of measuring sediment transport of sand beds by radioactive tracers; Methode du bilan des taux de comptage d'indicateurs radioactifs pour la determination du debit de charriage des lits sableux

    Energy Technology Data Exchange (ETDEWEB)

    Sauzay, G [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

    1967-11-01

    Radioactive tracers are applied to the direct measurement of the sediment transport rate of sand beds. The theoretical measurement formula is derived: the variation of the count rate balance is inverse of that of the transport thickness. Simultaneously the representativeness of the tracer is critically studied. The minimum quantity of tracer which has to be injected in order to obtain a correct statistical definition of count rate given by a low number of grains 'seen' by the detector is then studied. A field experiment was made and has let to study the technological conditions for applying this method: only the treatment of results is new, the experiment itself is carried out with conventional techniques applied with great care. (author) [French] Les indicateurs radioactifs sont appliques a la mesure directe du debit de charriage des lits sableux. On etablit la formule theorique de mesure: le bilan des taux de comptage varie en sens inverse de l'epaisseur de charriage. Parallelement on fait une etude critique de la representativite de l'indicateur, puis on determine la quantite minimale de traceur qu'il faut immerger pour que les taux de comptage fournis pour un faible nombre de grains 'vus' par le detecteur aient une definition statistique correcte. Une experience de terrain a permis d'etudier les conditions technologiques de cette methode: seul le depouillement des resultats est nouveau. L'experimentation in-situ se fait suivant les procedes classiques avec un tres grand soin. (auteur)

  4. Metal and trace element sediment assessment from Guarapiranga reservoir, Alto Tiete Basin, Sao Paulo, SP, Brazil; Avaliacao da concentracao de metais e elementos traco em amostras de sedimento do reservatorio Guarapiranga, Sao Paulo, SP, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Guilherme Moura

    2011-07-01

    The Guarapiranga Reservoir, located in Sao Paulo metropolitan region, Brazil, is responsible for supplying about 20% of the entire population's water needs of this region or approximately 3.7 million people. However, this system has shown significant degradation in water quality, due to untreated domestic sewage and industrial effluents. In this study sediment samples were collected at five points along the reservoir and total concentration of some major (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Hg, Rb, Sb, Sc, Ta, Tb, Th, U, V and Zn) and rare earth (Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) elements were determined by instrumental neutron activation analysis (INAA). By inductively coupled plasma optical emission spectrometry (ICP OES) the concentrations of Al, Ba, Be, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Ti, V e Zn were determined after digestion procedure following US EPA 3051 methodology. The concentrations of metals Cd and Pb were determined by graphite furnace atomic absorption spectrometry (GFAAS) and total Hg by cold vapor atomic absorption spectrometry (CVAAS). Methodology validation according to precision and accuracy was performed by reference materials analyses for the three different analytical techniques used. Multielemental results obtained by INAA were compared to NASC (North American Shale Composite), Upper Continental Crust (UCC) and soil from Guarapiranga park values. The Enrichment Factor (EF) and Geo accumulation Index (Igeo) were also evaluated for these data. Metal concentration results by ICP OES and AAS in the samples were compared to the TEL and PEL oriented values established by the Canadian Council of Ministers of the Environment and also adopted by CETESB (Environmental Protection Agency of the Sao Paulo State). The results were also compared to regional reference values (VRR) of limnic sediments from the Alto Tiete Basin. From these data an assessment of metal and trace element accumulated in the sediments from the

  5. Metal and trace element sediment assessment from Guarapiranga reservoir, Alto Tiete Basin, Sao Paulo, SP, Brazil; Avaliacao da concentracao de metais e elementos traco em amostras de sedimento do reservatorio Guarapiranga, Sao Paulo, SP, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Guilherme Moura

    2011-07-01

    The Guarapiranga Reservoir, located in Sao Paulo metropolitan region, Brazil, is responsible for supplying about 20% of the entire population's water needs of this region or approximately 3.7 million people. However, this system has shown significant degradation in water quality, due to untreated domestic sewage and industrial effluents. In this study sediment samples were collected at five points along the reservoir and total concentration of some major (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Hg, Rb, Sb, Sc, Ta, Tb, Th, U, V and Zn) and rare earth (Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) elements were determined by instrumental neutron activation analysis (INAA). By inductively coupled plasma optical emission spectrometry (ICP OES) the concentrations of Al, Ba, Be, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Ti, V e Zn were determined after digestion procedure following US EPA 3051 methodology. The concentrations of metals Cd and Pb were determined by graphite furnace atomic absorption spectrometry (GFAAS) and total Hg by cold vapor atomic absorption spectrometry (CVAAS). Methodology validation according to precision and accuracy was performed by reference materials analyses for the three different analytical techniques used. Multielemental results obtained by INAA were compared to NASC (North American Shale Composite), Upper Continental Crust (UCC) and soil from Guarapiranga park values. The Enrichment Factor (EF) and Geo accumulation Index (Igeo) were also evaluated for these data. Metal concentration results by ICP OES and AAS in the samples were compared to the TEL and PEL oriented values established by the Canadian Council of Ministers of the Environment and also adopted by CETESB (Environmental Protection Agency of the Sao Paulo State). The results were also compared to regional reference values (VRR) of limnic sediments from the Alto Tiete Basin. From these data an assessment of metal and trace element accumulated in the sediments from the

  6. Are inundation limit and maximum extent of sand useful for differentiating tsunamis and storms? An example from sediment transport simulations on the Sendai Plain, Japan

    Science.gov (United States)

    Watanabe, Masashi; Goto, Kazuhisa; Bricker, Jeremy D.; Imamura, Fumihiko

    2018-02-01

    We examined the quantitative difference in the distribution of tsunami and storm deposits based on numerical simulations of inundation and sediment transport due to tsunami and storm events on the Sendai Plain, Japan. The calculated distance from the shoreline inundated by the 2011 Tohoku-oki tsunami was smaller than that inundated by storm surges from hypothetical typhoon events. Previous studies have assumed that deposits observed farther inland than the possible inundation limit of storm waves and storm surge were tsunami deposits. However, confirming only the extent of inundation is insufficient to distinguish tsunami and storm deposits, because the inundation limit of storm surges may be farther inland than that of tsunamis in the case of gently sloping coastal topography such as on the Sendai Plain. In other locations, where coastal topography is steep, the maximum inland inundation extent of storm surges may be only several hundred meters, so marine-sourced deposits that are distributed several km inland can be identified as tsunami deposits by default. Over both gentle and steep slopes, another difference between tsunami and storm deposits is the total volume deposited, as flow speed over land during a tsunami is faster than during a storm surge. Therefore, the total deposit volume could also be a useful proxy to differentiate tsunami and storm deposits.

  7. 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

  8. Reservoir architecture patterns of sandy gravel braided distributary channel

    Directory of Open Access Journals (Sweden)

    Senlin Yin

    2016-06-01

    Full Text Available The purpose of this study was to discuss shape, scale and superimposed types of sandy gravel bodies in sandy-gravel braided distributary channel. Lithofacies analysis, hierarchy bounding surface analysis and subsurface dense well pattern combining with outcrops method were used to examine reservoir architecture patterns of sandy gravel braided distributary channel based on cores, well logging, and outcrops data, and the reservoir architecture patterns of sandy gravel braided distributary channels in different grades have been established. The study shows: (1 The main reservoir architecture elements for sandy gravel braided channel delta are distributary channel and overbank sand, while reservoir flow barrier elements are interchannel and lacustrine mudstone. (2 The compound sand bodies in the sandy gravel braided delta distributary channel take on three shapes: sheet-like distributary channel sand body, interweave strip distributary channel sand body, single strip distributary channel sand body. (3 Identification marks of single distributary channel include: elevation of sand body top, lateral overlaying, “thick-thin-thick” feature of sand bodies, interchannel mudstone and overbank sand between distributary channels and the differences in well log curve shape of sand bodies. (4 Nine lithofacies types were distinguished in distributary channel unit interior, different channel units have different lithofacies association sequence.

  9. INCREASING WATERFLOOD RESERVES IN THE WILMINGTON OIL FIELD THROUGH IMPROVED RESERVOIR CHARACTERIZATION AND RESERVOIR MANAGEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Scott Walker; Chris Phillips; Roy Koerner; Don Clarke; Dan Moos; Kwasi Tagbor

    2002-02-28

    This project increased recoverable waterflood reserves in slope and basin reservoirs through improved reservoir characterization and reservoir management. The particular application of this project is in portions of Fault Blocks IV and V of the Wilmington Oil Field, in Long Beach, California, but the approach is widely applicable in slope and basin reservoirs. Transferring technology so that it can be applied in other sections of the Wilmington Field and by operators in other slope and basin reservoirs is a primary component of the project. This project used advanced reservoir characterization tools, including the pulsed acoustic cased-hole logging tool, geologic three-dimensional (3-D) modeling software, and commercially available reservoir management software to identify sands with remaining high oil saturation following waterflood. Production from the identified high oil saturated sands was stimulated by recompleting existing production and injection wells in these sands using conventional means as well as a short radius redrill candidate. Although these reservoirs have been waterflooded over 40 years, researchers have found areas of remaining oil saturation. Areas such as the top sand in the Upper Terminal Zone Fault Block V, the western fault slivers of Upper Terminal Zone Fault Block V, the bottom sands of the Tar Zone Fault Block V, and the eastern edge of Fault Block IV in both the Upper Terminal and Lower Terminal Zones all show significant remaining oil saturation. Each area of interest was uncovered emphasizing a different type of reservoir characterization technique or practice. This was not the original strategy but was necessitated by the different levels of progress in each of the project activities.

  10. Reservoir characteristics of middle pliocene deposits and their role in the formation of oil gas deposits of Azerbaijan shelf of the south Caspian

    International Nuclear Information System (INIS)

    Veliyeva, V.A.; Kabulova, A. Ya.

    2002-01-01

    Full text :Lithology-stratigraphical peculiarities of deposits of lower stage of productive series (P S) of Middle Pliocene their reservoir properties, correlation of individual horizons within the uplifts of the south Caspian was studied. Analysis of arenosity of lower stage of PS was studied. Azerbaijan shelf of South Caspian is located within depression zone of sedimentation basin generally, of Pliocene and post-Pliocene period of time, when sedimentation was mostly intensive and occurred in conditions of more deep sea basin. Azerbaijan shelf of south Caspian covers mainly two oil-gasp-bearing region as Absheron archipelago (north, north-eastern part of region) and Baku archipelago (southern part). Analysis of arenosity along the areas of the studied region showed, that in south-eastern direction and on the south eastern subsidence of each fold, as well as on the north-eastern wing their sand percent considerably increase whereas reservoir properties of sandy interbeds are improved

  11. Size distribution and carbonate content of the sediments of the western shelf of India

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, R.R.; Pylee, A.

    %). (2) The outer shelf (approximately 20 to 70 fms) is a zone of relict sediments, having relatively low rates of sedimentation and composed of fine to medium sands. Occasional patches of coarse iron stained sands and pebbles are also present...

  12. Understanding creep in sandstone reservoirs - theoretical deformation mechanism maps for pressure solution in granular materials

    Science.gov (United States)

    Hangx, Suzanne; Spiers, Christopher

    2014-05-01

    Subsurface exploitation of the Earth's natural resources removes the natural system from its chemical and physical equilibrium. As such, groundwater extraction and hydrocarbon production from subsurface reservoirs frequently causes surface subsidence and induces (micro)seismicity. These effects are not only a problem in onshore (e.g. Groningen, the Netherlands) and offshore hydrocarbon fields (e.g. Ekofisk, Norway), but also in urban areas with extensive groundwater pumping (e.g. Venice, Italy). It is known that fluid extraction inevitably leads to (poro)elastic compaction of reservoirs, hence subsidence and occasional fault reactivation, and causes significant technical, economic and ecological impact. However, such effects often exceed what is expected from purely elastic reservoir behaviour and may continue long after exploitation has ceased. This is most likely due to time-dependent compaction, or 'creep deformation', of such reservoirs, driven by the reduction in pore fluid pressure compared with the rock overburden. Given the societal and ecological impact of surface subsidence, as well as the current interest in developing geothermal energy and unconventional gas resources in densely populated areas, there is much need for obtaining better quantitative understanding of creep in sediments to improve the predictability of the impact of geo-energy and groundwater production. The key problem in developing a reliable, quantitative description of the creep behaviour of sediments, such as sands and sandstones, is that the operative deformation mechanisms are poorly known and poorly quantified. While grain-scale brittle fracturing plus intergranular sliding play an important role in the early stages of compaction, these time-independent, brittle-frictional processes give way to compaction creep on longer time-scales. Thermally-activated mass transfer processes, like pressure solution, can cause creep via dissolution of material at stressed grain contacts, grain

  13. A Study of the Optimal Planning Model for Reservoir Sustainable Management- A Case Study of Shihmen Reservoir

    Science.gov (United States)

    Chen, Y. Y.; Ho, C. C.; Chang, L. C.

    2017-12-01

    The reservoir management in Taiwan faces lots of challenge. Massive sediment caused by landslide were flushed into reservoir, which will decrease capacity, rise the turbidity, and increase supply risk. Sediment usually accompanies nutrition that will cause eutrophication problem. Moreover, the unevenly distribution of rainfall cause water supply instability. Hence, how to ensure sustainable use of reservoirs has become an important task in reservoir management. The purpose of the study is developing an optimal planning model for reservoir sustainable management to find out an optimal operation rules of reservoir flood control and sediment sluicing. The model applies Genetic Algorithms to combine with the artificial neural network of hydraulic analysis and reservoir sediment movement. The main objective of operation rules in this study is to prevent reservoir outflow caused downstream overflow, minimum the gap between initial and last water level of reservoir, and maximum sluicing sediment efficiency. A case of Shihmen reservoir was used to explore the different between optimal operating rule and the current operation of the reservoir. The results indicate optimal operating rules tended to open desilting tunnel early and extend open duration during flood discharge period. The results also show the sluicing sediment efficiency of optimal operating rule is 36%, 44%, 54% during Typhoon Jangmi, Typhoon Fung-Wong, and Typhoon Sinlaku respectively. The results demonstrate the optimal operation rules do play a role in extending the service life of Shihmen reservoir and protecting the safety of downstream. The study introduces a low cost strategy, alteration of operation reservoir rules, into reservoir sustainable management instead of pump dredger in order to improve the problem of elimination of reservoir sediment and high cost.

  14. Occurrence of gas hydrate in Oligocene Frio sand: Alaminos Canyon Block 818: Northern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Boswell, R.D.; Shelander, D.; Lee, M.; Latham, T.; Collett, T.; Guerin, G.; Moridis, G.; Reagan, M.; Goldberg, D.

    2009-07-15

    A unique set of high-quality downhole shallow subsurface well log data combined with industry standard 3D seismic data from the Alaminos Canyon area has enabled the first detailed description of a concentrated gas hydrate accumulation within sand in the Gulf of Mexico. The gas hydrate occurs within very fine grained, immature volcaniclastic sands of the Oligocene Frio sand. Analysis of well data acquired from the Alaminos Canyon Block 818 No.1 ('Tigershark') well shows a total gas hydrate occurrence 13 m thick, with inferred gas hydrate saturation as high as 80% of sediment pore space. Average porosity in the reservoir is estimated from log data at approximately 42%. Permeability in the absence of gas hydrates, as revealed from the analysis of core samples retrieved from the well, ranges from 600 to 1500 millidarcies. The 3-D seismic data reveals a strong reflector consistent with significant increase in acoustic velocities that correlates with the top of the gas-hydrate-bearing sand. This reflector extends across an area of approximately 0.8 km{sup 2} and delineates the minimal probable extent of the gas hydrate accumulation. The base of the inferred gas-hydrate zone also correlates well with a very strong seismic reflector that indicates transition into units of significantly reduced acoustic velocity. Seismic inversion analyses indicate uniformly high gas-hydrate saturations throughout the region where the Frio sand exists within the gas hydrate stability zone. Numerical modeling of the potential production of natural gas from the interpreted accumulation indicates serious challenges for depressurization-based production in settings with strong potential pressure support from extensive underlying aquifers.

  15. Sediment transport-storage relations for degrading, gravel bed channels

    Science.gov (United States)

    Thomas E. Lisle; Michael Church

    2002-01-01

    In a drainage network,sediment is transferred through a series of channel/valley segments (natural sediment storage reservoirs) that are distinguished from their neighbors by their particular capacity to store and transport sediment. We propose that the sediment transport capacity of each reservoir is a unique positive function of storage volume, which influences...

  16. Unique 'man-made' object: reservoirs B10 and B11 of Techa cascade and means for in-situ measurement of its contamination - Water, soil, bottom sediments

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Oleg; Potapov, Victor; Stepanov, Vyacheslav; Smirnov, Sergey; Volkovich, Anatoly [National Research Centre - Kurchatov Institute, 1 Kurchatov Sq., Moscow (Russian Federation)

    2014-07-01

    Contamination of natural objects - alarm fallout zones and flood plains near production sites (the result of technological accidents and resource extraction) occupy large areas. Large area and volume of pollution, moderate activity facilities (at low and medium-level rad-wastes) to make such objects specific types of radioactive waste. These objects exist for a long time, now they are characterized by a bound state of nuclides with the matrix. There are no cost-effective ways to remove these rad-wastes, the only solution for the rehabilitation of such areas is their isolation and regular monitoring through direct and indirect measurements. The task of mapping and subsequent monitoring of pollution is very complex. Most of the complexity of the laboratory measurement techniques, as well as high levels of contamination (to 10{sup 9} Bk/m{sup 2}) for radionuclides Cs-137 and Sr-90 require for mapping pollution field physical methods of measurement of the specific activity of radionuclides directly on the ground. The set of instruments for in-situ contamination measurements: a portable spectrometric collimated detector, collimated borehole spectrometric detector, underwater spectrometric detector, spectrometer for field measurements of the specific activity of Sr-90, connected to a portable MCA. The complex was used in Bryansk region, on the Techa river and Yenisei river. We present measurements of contamination in and around the reservoir No. 10 of Techa cascade containing a huge amount of radioactive waste. Measurements are performed in the framework of international expeditions in 2008, 2011 and 2012. To develop plans and programs for the rehabilitation of non-standard large-size objects containing radioactive waste precise and detailed measurement data are necessary and very often there is not enough of such data. Measurements of contaminated water, soil and bottom sediments in area of water reservoirs of Techa cascade have shown that unique system of detectors and

  17. Saskatchewan's place in the Canadian oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, L.L. [Saskatchewan Research Council, Saskatoon, SK (Canada); Kramers, J.W. [Owl Ventures Inc., Edmonton, AB (Canada); Isaacs, E.E. [Alberta Energy Research Inst., Calgary, AB (Canada)

    2009-07-01

    This paper provided a detailed description of the oil sands geology and physical properties and highlighted some of the novel recovery technologies that are being developed for shallow in-situ reservoirs in Alberta and Saskatchewan. Canada's oil sands are well known around the world, with Alberta's mined and in-situ oil sands reservoirs being well developed with mature commercial technologies. Shallow in-situ oil sands located in both Saskatchewan and Alberta will be the next frontier in Canadian petroleum development. Shallow reservoirs will need to be developed with new environmentally sound in-situ technologies that will reduce the use of steam and fresh water, and also reduce greenhouse gas emissions. Research and development programs are currently underway to develop and demonstrate such new technologies. It was concluded that innovation has been the key to developing the immense and complex technology oil contained in Canada's heavy oil reservoirs and also in its shallow and deep in-situ oil sands reservoirs. Promising technologies include the solvent vapour extraction and hybrid thermal solvent extraction processes that are being developed and demonstrated in large-scale three-dimensional scaled physical models and associated numerical simulation models. Electrical heating and gravity stable combustion are other examples of technologies that could play a significant role in developing these resources. 88 refs., 3 tabs., 8 figs.

  18. Major occurrences and reservoir concepts of marine clathrate hydrates: Implications of field evidence

    Science.gov (United States)

    Booth, J.S.; Winters, W.J.; Dillon, William P.; Clennell, M.B.; Rowe, M.M.

    1998-01-01

    This paper is part of the special publication Gas hydrates: relevance to world margin stability and climatic change (eds J.P. Henriet and J. Mienert). Questions concerning clathrate hydrate as an energy resource, as a factor in modifying global climate and as a triggering mechanism for mass movements invite consideration of what factors promote hydrate concentration, and what the quintessential hydrate-rich sediment may be. Gas hydrate field data, although limited, provide a starting point for identifying the environments and processes that lead to more massive concentrations. Gas hydrate zones are up to 30 m thick and the vertical range of occurrence at a site may exceed 200 m. Zones typically occur more than 100m above the phase boundary. Thicker zones are overwhelmingly associated with structural features and tectonism, and often contain sand. It is unclear whether an apparent association between zone thickness and porosity represents a cause-and-effect relationship. The primary control on the thickness of a potential gas hydrate reservoir is the geological setting. Deep water and low geothermal gradients foster thick gas hydrate stability zones (GHSZs). The presence of faults, fractures, etc. can favour migration of gas-rich fluids. Geological processes, such as eustacy or subsidence, may alter the thickness of the GHSZ or affect hydrate concentratiion. Tectonic forces may promote injection of gas into the GHSZ. More porous and permeable sediment, as host sediment properties, increase storage capacity and fluid conductivity, and thus also enhance reservoir potential.

  19. Coastal change from a massive sediment input: Dam removal, Elwha River, Washington, USA

    Science.gov (United States)

    Warrick, Jonathan A.; Gelfenbaum, Guy R.; Stevens, Andrew; Miller, Ian M.; Kaminsky, George M.; Foley, Melissa M.

    2015-01-01

    The removal of two large dams on the Elwha River, Washington, provides an ideal opportunity to study coastal morphodynamics during increased sediment supply. The dam removal project exposed ~21 million cubic meters (~30 million tonnes) of sediment in the former reservoirs, and this sediment was allowed to erode by natural river processes. Elevated rates of sand and gravel sediment transport in the river occurred during dam removal. Most of the sediment was transported to the coast, and this renewed sediment supply resulted in hundreds of meters of seaward expansion of the river delta since 2011. Our most recent survey in January 2015 revealed that a cumulative ~3.5 million m3 of sediment deposition occurred at the delta since the beginning of the dam removal project, and that aggradation had exceeded 8 m near the river mouth. Some of the newly deposited sediment has been shaped by waves and currents into a series of subaerial berms that appear to move shoreward with time.

  20. Sediment supply to beaches

    DEFF Research Database (Denmark)

    Aagaard, Troels

    2014-01-01

    Many beaches have been built by an onshore supply of sand from the shoreface, and future long-term coastal evolution critically depends on cross-shore sediment exchange between the upper and the lower shorefaces. Even so, cross-shore sediment supply remains poorly known in quantitative terms...... and this reduces confidence in predictions of long-term shoreline change. In this paper, field measurements of suspended sediment load and cross-shore transport on the lower shoreface are used to derive a model for sediment supply from the lower to the upper shoreface at large spatial and temporal scales. Data...

  1. Characterization of sand lenses and their role for subsurface transport in low-permeability clay tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Klint, K. E.; Nilsson, B.

    2011-01-01

    Glacial sediments dominate large parts of the geological topology in Denmark. They predominantly consist of lowpermeability tills, but fractures and sand-lenses constitute zones of enhanced permeability facilitating preferential flow. This study focuses on characterization of sand deposits with r...... the sand lenses in hydro-geological models to successfully characterize subsurface flow and transport, e.g. for remediation activities....

  2. Scour at Vertical Piles in Sand-Clay Mixtures under Waves

    DEFF Research Database (Denmark)

    Dey, Subhasish; Helkjær, Anders; Sumer, B. Mutlu

    2011-01-01

    Marine sediments often contain sand-clay mixtures in widely varying proportions. This study presents the results of equilibrium scour and time variation of scour depths at circular piles embedded vertically in clay alone and sand-clay mixed beds under waves. Experiments were conducted in a wave...... flume with different proportions of sand-clay mixtures as bed sediments. Test results for the cases of steady current and sand alone under waves are used as references. The equilibrium scour depth reduces with an increase in clay proportion n (by weight) in a sand-clay mixture. Interestingly, the scour...

  3. 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.

  4. 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.

  5. Understanding the mechanical and acoustical characteristics of sand aggregates compacting under triaxial conditions

    Science.gov (United States)

    Hangx, Suzanne; Brantut, Nicolas

    2016-04-01

    Mechanisms such as grain rearrangement, coupled with elastic deformation, grain breakage, grain rearrangement, grain rotation, and intergranular sliding, play a key role in determining porosity and permeability reduction during burial of clastic sediments. Similarly, in poorly consolidated, highly porous sands and sandstones, grain rotation, intergranular sliding, grain failure, and pore collapse often lead to significant reduction in porosity through the development of compaction bands, with the reduced porosity and permeability of such bands producing natural barriers to flow within reservoir rocks. Such time-independent compaction processes operating in highly porous water- and hydrocarbon-bearing clastic reservoirs can exert important controls on production-related reservoir deformation, subsidence, and induced seismicity. We performed triaxial compression experiments on sand aggregates consisting of well-rounded Ottawa sand (d = 300-400 μm; φ = 36.1-36.4%) at room temperature, to systematically investigate the effect of confining pressure (Pceff = 5-100 MPa), strain rate (10-6-10-4 s-1) and chemical environment (decane vs. water; Pf = 5 MPa) on compaction. For a limited number of experiments grain size distribution (d = 180-500 μm) and grain shape (subangular Beaujean sand; d = 180-300 μm) were varied to study their effect. Acoustic emission statistics and location, combined with microstructural and grain size analysis, were used to verify the operating microphysical compaction mechanisms. All tests showed significant pre-compaction during the initial hydrostatic (set-up) phase, with quasi-elastic loading behaviour accompanied by permanent deformation during the differential loading stage. This permanent volumetric strain involved elastic grain contact distortion, particle rearrangement, and grain failure. From the acoustic data and grain size analysis, it was evident that at low confining pressure grain rearrangement controlled compaction, with grain

  6. Suitability of river delta sediment as proppant, Missouri and Niobrara Rivers, Nebraska and South Dakota, 2015

    Science.gov (United States)

    Zelt, Ronald B.; Hobza, Christopher M.; Burton, Bethany L.; Schaepe, Nathaniel J.; Piatak, Nadine

    2017-11-16

    Sediment management is a challenge faced by reservoir managers who have several potential options, including dredging, for mitigation of storage capacity lost to sedimentation. As sediment is removed from reservoir storage, potential use of the sediment for socioeconomic or ecological benefit could potentially defray some costs of its removal. Rivers that transport a sandy sediment load will deposit the sand load along a reservoir-headwaters reach where the current of the river slackens progressively as its bed approaches and then descends below the reservoir water level. Given a rare combination of factors, a reservoir deposit of alluvial sand has potential to be suitable for use as proppant for hydraulic fracturing in unconventional oil and gas development. In 2015, the U.S. Geological Survey began a program of researching potential sources of proppant sand from reservoirs, with an initial focus on the Missouri River subbasins that receive sand loads from the Nebraska Sand Hills. This report documents the methods and results of assessments of the suitability of river delta sediment as proppant for a pilot study area in the delta headwaters of Lewis and Clark Lake, Nebraska and South Dakota. Results from surface-geophysical surveys of electrical resistivity guided borings to collect 3.7-meter long cores at 25 sites on delta sandbars using the direct-push method to recover duplicate, 3.8-centimeter-diameter cores in April 2015. In addition, the U.S. Geological Survey collected samples of upstream sand sources in the lower Niobrara River valley.At the laboratory, samples were dried, weighed, washed, dried, and weighed again. Exploratory analysis of natural sand for determining its suitability as a proppant involved application of a modified subset of the standard protocols known as American Petroleum Institute (API) Recommended Practice (RP) 19C. The RP19C methods were not intended for exploration-stage evaluation of raw materials. Results for the washed samples are

  7. Underwater Sediment Sampling Research

    Science.gov (United States)

    2017-01-01

    impacted sediments was found to be directly related to the concentration of crude oil detected in the sediment pore waters . Applying this mathematical...Kurt.A.Hansen@uscg.mil. 16. Abstract (MAXIMUM 200 WORDS ) The USCG R&D Center sought to develop a bench top system to determine the amount of total...scattered. The approach here is to sample the interstitial water between the grains of sand and attempt to determine the amount of oil in and on

  8. 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...

  9. 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

  10. Geological modeling for methane hydrate reservoir characterization in the eastern Nankai Trough, offshore Japan

    Science.gov (United States)

    Tamaki, M.; Komatsu, Y.; Suzuki, K.; Takayama, T.; Fujii, T.

    2012-12-01

    The eastern Nankai trough, which is located offshore of central Japan, is considered as an attractive potential resource field of methane hydrates. Japan Oil, Gas and Metals National Corporation is planning to conduct a production test in early 2013 at the AT1 site in the north slope of Daini-Atsumi Knoll in the eastern Nankai Trough. The depositional environment of methane hydrate-bearing sediments around the production test site is a deep submarine-fan turbidite system, and it is considered that the reservoir properties should show lateral as well as vertical heterogeneity. Since the variations in the reservoir heterogeneity have an impact on the methane hydrate dissociation and gas production performance, precise geological models describing reservoir heterogeneity would be required for the evaluation of reservoir potentials. In preparation for the production test, 3 wells; two monitoring boreholes (AT1-MC and AT1-MT1) and a coring well (AT1-C), were newly acquired in 2012. In addition to a geotechnical hole drilling survey in 2011 (AT1-GT), totally log data from 2 wells and core data from 2 wells were obtained around the production test site. In this study, we conducted well correlations between AT1 and A1 wells drilled in 2003 and then, 3D geological models were updated including AT1 well data in order to refine hydrate reservoir characterization around the production test site. The results of the well correlations show that turbidite sand layers are characterized by good lateral continuity, and give significant information for the distribution morphology of sand-rich channel fills. We also reviewed previously conducted 3D geological models which consist of facies distributions and petrophysical properties distributions constructed from integration of 3D seismic data and a well data (A1 site) adopting a geostatistical approach. In order to test the practical validity of the previously generated models, cross-validation was conducted using AT1 well data. The

  11. Reconstruction of the sediment flow regime in a semi-arid Mediterranean catchment using check dam sediment information.

    Science.gov (United States)

    Bussi, G.; Rodríguez, X.; Francés, F.; Benito, G.; Sánchez-Moya, Y.; Sopeña, A.

    2012-04-01

    When using hydrological and sedimentological models, lack of historical records is often one of the main problems to face, since observed data are essential for model validation. If gauged data are poor or absent, a source of additional proxy data may be the slack-water deposits accumulated in check dams. The aim of this work is to present the result of the reconstruction of the recent hydrological and sediment yield regime of a semi-arid Mediterranean catchment (Rambla del Poyo, Spain, 184 square km) by coupling palaeoflood techniques with a distributed hydrological and sediment cycle model, using as proxy data the sandy slack-water deposits accumulated upstream a small check dam (reservoir volume 2,500 square m) located in the headwater basin (drainage area 13 square km). The solid volume trapped into the reservoir has been estimated using differential GPS data and an interpolation technique. Afterwards, the total solid volume has been disaggregated into various layers (flood units), by means of a stratigraphical description of a depositional sequence in a 3.5 m trench made across the reservoir sediment deposit, taking care of identifying all flood units; the separation between flood units is indicated by a break in deposition. The sedimentary sequence shows evidence of 15 flood events that occurred after the dam construction (early '90). Not all events until the present are included; for the last ones, the stream velocity and energy conditions for generating slack-water deposits were not fulfilled due to the reservoir filling. The volume of each flood unit has been estimated making the hypothesis that layers have a simple pyramidal shape (or wedge); every volume represents an estimation of the sediments trapped into the reservoir corresponding to each flood event. The obtained results have been compared with the results of modeling a 20 year time series (1990 - 2009) with the distributed conceptual hydrological and sediment yield model TETIS-SED, in order to

  12. 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

  13. Benthic faunal sampling adjacent to the Sand Island ocean outfall, Oahu, Hawaii, 1986-2010 (NODC Accession 9900088)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic fauna in the vicinity of the Sand Island ocean outfall were sampled from 1986-2010. To assess the environmental quality, sediment grain size and sediment...

  14. Estimation of suspended sediment concentration by acoustic ...

    African Journals Online (AJOL)

    concentration of sediments such as glass spheres or sand. However, the acoustic properties of natural sediments vary and depend on many parameters such as particle size, shape, mineralogy and distribution of those parameters in sample. Therefore, this study was conducted to determine the possibility of soil sediment ...

  15. Sedimentation problems and solutions

    International Nuclear Information System (INIS)

    Williams, D.T.

    1991-01-01

    Roseires Dam and reservoir are located in Sudan, Africa on the Blue Nile River. The hydropower from the reservoir provides approximately 80% of the power used in Sudan, thus having a tremendous economic impact on the country. The reservoir was first impounded in 1966 and has been filled annually since then. The Blue Nile has historically been known to carry heavy sediment loads which is associated with erosion from overgrazing in Ethiopia, the Blue Nile's headwaters. During the flood season, the dam's turbine intakes become blocked with debris and sediment. After a severe blockage in 1981, which prevented hydropower generation for several days, consultants from USAID were asked to make recommendations on reducing the sediment and debris impacts on reservoir operations. This led to debris clearing and dredging equipment acquisitions in 1982. In 1988, blockage occurred again during the flood season. This writer was asked by the World Bank to travel to Sudan, investigate the sediment and debris problems, examine the USAID recommendations, comment on potential sediment and debris problems associated with a proposed plan to raise the dam, make additional recommendations, and return to Sudan several times to determine the effectiveness of there recommendations. This paper discussed the results of the aforementioned activities and describes the new recommendations made by this writer

  16. Sand waves on an epicontinental shelf: Northern Bering Sea

    Science.gov (United States)

    Field, M.E.; Nelson, C.H.; Cacchione, D.A.; Drake, D.E.

    1981-01-01

    Sand waves and current ripples occupy the crests and flanks of a series of large linear sand ridges (20 km ?? 5 km ?? 10 m high) lying in an open-marine setting in the northern Bering Sea. The sand wave area, which lies west of Seward Peninsula and southeast of Bering Strait, is exposed to the strong continuous flow of coastal water northward toward Bering Strait. A hierarchy of three sizes of superimposed bedforms, all facing northward, was observed in successive cruises in 1976 and 1977. Large sand waves (height 2 m; spacing 200 m) have smaller sand waves (height 1 m; spacing 20 m) lying at a small oblique angle on their stoss slopes. The smaller sand waves in turn have linguoid ripples on their stoss slopes. Repeated studies of the sand wave fields were made both years with high-resolution seismic-reflection profiles, side-scan sonographs, underwater photographs, current-meter stations, vibracores, and suspended-sediment samplers. Comparison of seismic and side-scan data collected along profile lines run both years showed changes in sand wave shape that indicate significant bedload transport within the year. Gouge marks made in sediment by keels of floating ice also showed significantly different patterns each year, further documenting modification to the bottom by sediment transport. During calm sea conditions in 1977, underwater video and camera observations showed formation and active migration of linguoid and straight-crested current ripples. Current speeds 1 m above the bottom were between 20 and 30 cm/s. Maximum current velocities and sand wave migration apparently occur when strong southwesterly winds enhance the steady northerly flow of coastal water. Many cross-stratified sand bodies in the geologic record are interpreted as having formed in a tidal- or storm-dominated setting. This study provides an example of formation and migration of large bedforms by the interaction of storms with strong uniform coastal currents in an open-marine setting. ?? 1981.

  17. Use of flux and morphologic sediment budgets for sandbar monitoring on the Colorado River in Marble Canyon, Arizona

    Science.gov (United States)

    Grams, Paul E.; Buscombe, Daniel D.; Topping, David J.; Hazel, Joseph E.; Kaplinski, Matt

    2015-01-01

    The magnitude and pfattern of streamflow and sediment supply of the Colorado River in Grand Canyon (Figure 1) has been affected by the existence and operations of Glen Canyon Dam since filling of Lake Powell Reservoir began in March 1963. In the subsequent 30 years, fine sediment was scoured from the downstream channel (Topping et al., 2000; Grams et al., 2007), resulting in a decline in the number and size of sandbars in the eastern half of Grand Canyon National Park (Wright et al., 2005; Schmidt et al., 2004). The Glen Canyon Dam Adaptive Management Program (GCDAMP) administered by the U.S. Department of Interior oversees efforts to manage the Colorado River ecosystem downstream from Glen Canyon Dam. One of the goals of the GCDAMP is to maintain and increase the number and size of sandbars in this context of a limited sand supply. Management actions to benefit sandbars have included curtailment of daily streamflow fluctuations, which occur for hydropower generation, and implementation of controlled floods, also called high-flow experiments.Studies of controlled floods, defined as intentional releases that exceed the maximum discharge capacity of the Glen Canyon Dam powerplant, implemented between 1996 and 2008, have demonstrated that these events cause increases in sandbar size throughout Marble and Grand Canyons (Hazel et al., 2010; Schmidt and Grams, 2011; Mueller et al., 2014), although the magnitude of response is spatially variable (Hazel et al., 1999; 2010). Controlled floods may build some sandbars at the expense of erosion of sand from other, upstream, sandbars (Schmidt, 1999). To increase the frequency and effectiveness of sandbar building, the U.S. Department of Interior adopted a “high-flow experimental protocol” to implement controlled floods regularly under conditions of enriched sand supply (U.S. Department of Interior, 2012). Because the supply of sand available to build sandbars has been substantially reduced by Glen Canyon Dam (Topping et al

  18. A study of global sand seas

    Science.gov (United States)

    McKee, Edwin D.

    1979-01-01

    associated with eolian hydrocarbon reservoirs. The final chapters present a discussion of the morphology and distribution of dunes as determined largely from Landsat images.Chapter K of the publication is devoted to descriptions of major sand seas based largely on thematic maps derived from Landsat (ERTS) mosaics. Although inclusion herein of the actual mosaics proved to be impractical, the maps derived from them do show the distribution and abundance of various dune types and the relations of these types to certain associated features, such as bedrock, water bodies, and juxtaposed dunes. Furthermore, sand roses included with each of these maps enable the user to draw conclusions on the probable relations of wind strength and direction to dune type in a particular area.Regional studies (chapter K) were a team effort. Analysis of the Landsat (ERTS) mosaics and mapping boundaries of individual dune types were by Carol Breed. Synthesis of the rather voluminous literature and preparation of abstracts covering it was by Camilla MacCauley. Actual preparation of maps was by Franci Lennartz and later by Sarah Andrews. The gathering of data on wind, the calculation of wind roses, and the interpretation of their relations to sand bodies were by Steven Fryberger, assisted by Gary Dean.

  19. Comparaison de diverses méthodes de dosage des argiles d'un sable de gisement. Dosage des argiles Comparison of Different Methods of Determining Clays in a Reservoir Sand. Quantitative Analysis of Clays

    Directory of Open Access Journals (Sweden)

    Yvon J.

    2006-11-01

    Full Text Available Les argiles d'un sable de gisement, concentrées dans la fraction de diamètre Phi Oil, gas and geothermal reservoirs all contain clayey fractions no matter how small they may be. This has been blamed whenever operating or producing problems arise. It may be revealed by phenomena of mechanical resistance, permeability or interfacial properties (ion exchange, adsorption, etc. . Tests to understand such phenomena then go via the quantitative mineralogical analysis of the clays present. This analysis must also be looked at in terms of methods. It is subjected to constraints of cost, instrumentation, competence or deadlines. This article proposes:(a A so-called conventional route (Dejou et al, 1977 based on chemical and weighted analyses. (b An overall assessment method of the clay phase by difference (determination of two nonclay species. (c A method based on the statistical processing of microanalytic data obtained by an electronic microprobe. The material examined was a quartzose arenite made up mainly of quartz, jarosite, orthoclase, plagioclases, calcite, dolomite, muscovite, kaolinite, illite, montmorillonite, interstratified illite-montmorillionite, iron oxyhydroxides and accessory minerals such as rutile, zircon, garnet, tourmaline and hydroxylapatite. The arenite was subjected to an ultrasonic treatment (Letelier, 1986 to recover pellicular or weakly cemented clays. After this treatment, all the free clays were found in the < 40 m fraction which were used for the measurements. The so-called conventionalmethod is based on the associating of multiple techniques that are normally used for analyzing clays. They include X-ray diffraction, TDA, TGA, selective dissolution, CEC, adsorption of various reagents and gravimetric separations. They have been reviewed by Dejou et al (1977. The results they give depend on the grain size, chrystallochemistry, presence of amorphous elements and especially the typical chemical compositions assigned to the

  20. Increasing Waterflooding Reservoirs in the Wilmington Oil Field through Improved Reservoir Characterization and Reservoir Management

    Energy Technology Data Exchange (ETDEWEB)

    Koerner, Roy; Clarke, Don; Walker, Scott

    1999-11-09

    The objectives of this quarterly report was to summarize the work conducted under each task during the reporting period April - June 1998 and to report all technical data and findings as specified in the ''Federal Assistance Reporting Checklist''. The main objective of this project is the transfer of technologies, methodologies, and findings developed and applied in this project to other operators of Slope and Basin Clastic Reservoirs. This project will study methods to identify sands with high remaining oil saturation and to recomplete existing wells using advanced completion technology.

  1. Geomechanical, Hydraulic and Thermal Characteristics of Deep Oceanic Sandy Sediments Recovered during the Second Ulleung Basin Gas Hydrate Expedition

    Directory of Open Access Journals (Sweden)

    Yohan Cha

    2016-09-01

    Full Text Available This study investigates the geomechanical, hydraulic and thermal characteristics of natural sandy sediments collected during the Ulleung Basin gas hydrate expedition 2, East Sea, offshore Korea. The studied sediment formation is considered as a potential target reservoir for natural gas production. The sediments contained silt, clay and sand fractions of 21%, 1.3% and 77.7%, respectively, as well as diatomaceous minerals with internal pores. The peak friction angle and critical state (or residual state friction angle under drained conditions were ~26° and ~22°, respectively. There was minimal or no apparent cohesion intercept. Stress- and strain-dependent elastic moduli, such as tangential modulus and secant modulus, were identified. The sediment stiffness increased with increasing confining stress, but degraded with increasing strain regime. Variations in water permeability with water saturation were obtained by fitting experimental matric suction-water saturation data to the Maulem-van Genuchen model. A significant reduction in thermal conductivity (from ~1.4–1.6 to ~0.5–0.7 W·m−1·K−1 was observed when water saturation decreased from 100% to ~10%–20%. In addition, the electrical resistance increased quasi-linearly with decreasing water saturation. The geomechanical, hydraulic and thermal properties of the hydrate-free sediments reported herein can be used as the baseline when predicting properties and behavior of the sediments containing hydrates, and when the hydrates dissociate during gas production. The variations in thermal and hydraulic properties with changing water and gas saturation can be used to assess gas production rates from hydrate-bearing deposits. In addition, while depressurization of hydrate-bearing sediments inevitably causes deformation of sediments under drained conditions, the obtained strength and stiffness properties and stress-strain responses of the sedimentary formation under drained loading conditions

  2. limnological study of the Guavio Reservoir (Colombia)

    International Nuclear Information System (INIS)

    Roldan, Gabriel; Bohorquez, Amparo; Catano, Ramiro; Ardila, Jorge I

    2000-01-01

    From September to December 1996, a limnological study of el Guavio reservoir from o to 100m deep was undertaken. Samples of plankton were taken and chlorophyll a determined. The study showed a well-mixed column of water. Dissolved oxygen remained 60% saturation at 100m deep. Values of phosphorus and nitrogen, as well chlorophyll was very low. Phytoplankton and zooplankton were diverse. The main problem of the reservoir is sediments coming from very erossionable surroundings

  3. Transport processes in intertidal sand flats

    Science.gov (United States)

    Wu, Christy

    2010-05-01

    Methane rich sulfate depleted seeps are observed along the low water line of the intertidal sand flat Janssand in the Wadden Sea. It is unclear where in the flat the methane is formed, and how it is transported to the edge of the sand flat where the sulfidic water seeps out. Methane and sulfate distributions in pore water were determined along transects from low water line toward the central area of the sand flat. The resulting profiles showed a zone of methane-rich and sulfate-depleted pore water below 2 m sediment depth. Methane production and sulfate reduction are monitored over time for surface sediments collected from the upper flat and seeping area. Both activities were at 22 C twice as high as at 15 C. The rates in sediments from the central area were higher than in sediments from the methane seeps. Methanogenesis occurred in the presence of sulfate, and was not significantly accelerated when sulfate was depleted. The observations show a rapid anaerobic degradation of organic matter in the Janssand. The methane rich pore water is obviously transported with a unidirectional flow from the central area of the intertidal sand flat toward the low water line. This pore water flow is driven by the pressure head caused by elevation of the pore water relative to the sea surface at low tide (Billerbeck et al. 2006a). The high methane concentration at the low water line accumulates due to a continuous outflow of pore water at the seepage site that prevents penetration of electron acceptors such as oxygen and sulfate to reoxidize the reduced products of anaerobic degradation (de Beer et al. 2006). It is, however, not clear why no methane accumulates or sulfate is depleted in the upper 2 m of the flats.

  4. 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.

  5. 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 ...

  6. External costs of sand mining in rivers: evidence from South Africa.

    CSIR Research Space (South Africa)

    De Lange, Willem J

    2009-05-01

    Full Text Available river sand load content and excluding the impacts of dams and sand mining). Accounting for the impacts of dams on sediment yield decreased the estimate by at least 33 percent (Theron et al., 2008). An aerial survey identified thirty-one active sand... mining operations, extracting approximately 400 000 cubic meters of sand per year (a conservative estimate) in the eThekwini area (Theron et al., 2008). The estimated remaining sediment yield from rivers after accounting for the impacts of dams...

  7. Marine pollution: Let us not forget beach sand

    OpenAIRE

    Galgani, Francois; Ellerbrake, Katrin; Fries, Elke; Goreux, Chantal

    2011-01-01

    Background: Assessing the chemical or bacterial contamination in marine waters and sediments is a very common approach to evaluate marine pollution and associated risks. However, toxicity and organic pollution of beach sands have not yet been considered, except in adjacent waters. In the present study, the toxicity and the chemical contamination of natural beach sands collected 20 m from the shoreline at two sites located on the Mediterranean Sea (Marseille and La Marana, Corsica) were studie...

  8. Evolution of Seismic Velocities in Heavy Oil Sand Reservoirs during Thermal Recovery Process Évolution des vitesses sismiques dans les réservoirs de sables bitumineux au cours des procédés de récupération thermique

    Directory of Open Access Journals (Sweden)

    Nauroy J.-F.

    2013-01-01

    Full Text Available In thermally enhanced recovery processes like Cyclic Steam Stimulation (CSS or Steam Assisted Gravity Drainage (SAGD, continuous steam injection entails changes in pore fluid, pore pressure and temperature in the rock reservoir, that are most often unconsolidated or weakly consolidated sandstones. This in turn increases or decreases the effective stresses and changes the elastic properties of the rocks. Thermally enhanced recovery processes give rise to complex couplings. 4D seismic surveys are currently conducted to delineate the steam-affected areas but the interpretation is difficult. However, it is essential for optimization of reservoir development. Numerical simulations have been carried out on a case study so as to provide an estimation of the evolution of pressure, temperature, pore fluid saturation, stress and strain in any zone located around the injector and producer wells. The approach of Ciz and Shapiro (2007 (Geophysics 72, A75-A79 has been used to model the velocity dispersion in the oil sand mass under different conditions of temperature and stress. A good agreement has been found between these predictions and some laboratory velocity measurements carried out on samples of Canadian oil sand. Results appear to be useful to better interpret 4D seismic data in order to locate the steam chamber. Dans les procédés de récupération des huiles lourdes par méthodes thermiques, comme ia stimulation cyclique par vapeur (CSS ou le drainage par gravité assisté par vapeur (SAGD, l’injection de vapeur en continu entraîne des changements de liquide de pores, de pression interstitielle et de température dans la roche réservoir, qui est constituée le plus souvent de sable non consolidés ou faiblement consolidés- Ces changements à leur tour augmentent ou diminuent les contraintes effectives et modifient les propriétés élastiques des roches. Les procédés de récupération par méthodes thermiques mettent en oeuvre des couplages

  9. A SEDIMENT TOXICITY METHOD USING LEMNA MINOR, DUCKWEED

    Science.gov (United States)

    We developed a Lemna minor sediment toxicity test method to assess sediment contaminants which may affect plants. This 96-hour test used 15 ml of sediment and 2 ml of overlying water which was renewed after 48 hours. Sand was used as the control sediment and also to dilute test ...