WorldWideScience

Sample records for mackenzie river delta

  1. Mackenzie River Delta, Canada

    Science.gov (United States)

    2007-01-01

    The Mackenzie River in the Northwest Territories, Canada, with its headstreams the Peace and Finley, is the longest river in North America at 4241 km, and drains an area of 1,805,000 square km. The large marshy delta provides habitat for migrating Snow Geese, Tundra Swans, Brant, and other waterfowl. The estuary is a calving area for Beluga whales. The Mackenzie (previously the Disappointment River) was named after Alexander Mackenzie who travelled the river while trying to reach the Pacific in 1789. The image was acquired on August 4, 2005, covers an area of 55.8 x 55.8 km, and is located at 68.6 degrees north latitude, 134.7 degrees west longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  2. Mackenzie River Delta morphological change based on Landsat time series

    Science.gov (United States)

    Vesakoski, Jenni-Mari; Alho, Petteri; Gustafsson, David; Arheimer, Berit; Isberg, Kristina

    2015-04-01

    Arctic rivers are sensitive and yet quite unexplored river systems to which the climate change will impact on. Research has not focused in detail on the fluvial geomorphology of the Arctic rivers mainly due to the remoteness and wideness of the watersheds, problems with data availability and difficult accessibility. Nowadays wide collaborative spatial databases in hydrology as well as extensive remote sensing datasets over the Arctic are available and they enable improved investigation of the Arctic watersheds. Thereby, it is also important to develop and improve methods that enable detecting the fluvio-morphological processes based on the available data. Furthermore, it is essential to reconstruct and improve the understanding of the past fluvial processes in order to better understand prevailing and future fluvial processes. In this study we sum up the fluvial geomorphological change in the Mackenzie River Delta during the last ~30 years. The Mackenzie River Delta (~13 000 km2) is situated in the North Western Territories, Canada where the Mackenzie River enters to the Beaufort Sea, Arctic Ocean near the city of Inuvik. Mackenzie River Delta is lake-rich, productive ecosystem and ecologically sensitive environment. Research objective is achieved through two sub-objectives: 1) Interpretation of the deltaic river channel planform change by applying Landsat time series. 2) Definition of the variables that have impacted the most on detected changes by applying statistics and long hydrological time series derived from Arctic-HYPE model (HYdrologic Predictions for Environment) developed by Swedish Meteorological and Hydrological Institute. According to our satellite interpretation, field observations and statistical analyses, notable spatio-temporal changes have occurred in the morphology of the river channel and delta during the past 30 years. For example, the channels have been developing in braiding and sinuosity. In addition, various linkages between the studied

  3. Geogenic Sources Strongly Contribute to the Mackenzie River Delta's Methane Emissions Derived From Airborne Flux Data

    Science.gov (United States)

    Kohnert, K.; Serafimovich, A.; Metzger, S.; Hartmann, J.; Sachs, T.

    2015-12-01

    Arctic permafrost-associated wetlands and thawing permafrost emit the greenhouse gas methane (CH4), either as a product of recent microbial activity in the active layer or taliks, or from deeper geogenic sources where pathways through the permafrost exist. Current emission estimates vary strongly between different models and there is still disagreement between bottom-up estimates from local field studies and top-down estimates from atmospheric measurements. We use airborne flux data from two campaigns in the Mackenzie River Delta, Canada, in July 2012 and 2013 to directly quantify permafrost CH4 emissions on the regional scale, to analyse the regional pattern of CH4 fluxes and to estimate the contribution of geogenic emissions to the overall CH4 budget of the delta. CH4 fluxes were calculated with a time-frequency resolved version of the eddy covariance technique, resulting in a gridded 100 m x 100 m resolution flux map within the footprints of the flight tracks. We distinguish geogenic gas seeps from biogenic sources by their strength and show that they contribute strongly to the annual CH4 budget of the delta. Our study provides the first estimate of annual CH4 release from the Mackenzie River Delta and the adjacent coastal plain. We show that one percent of the covered area contains the strongest geogenic seeps which contribute disproportionately to the annual emission estimate. Our results show that geogenic CH4 emissions might need more attention, especially in areas where permafrost is vulnerable to thawing sufficiently to create pathways for geogenic gas migration. The presented map can be used as a baseline for future CH4 flux studies in the Mackenzie River Delta.

  4. A Harbour Porpoise, Phocoena phocoena (Linnaeus, 1758), from the Mackenzie River delta, Northwest Territories, Canada (Notes on Cetacea, Delphinoidea VIII)

    NARCIS (Netherlands)

    Bree, van P.J.H.; Sergeant, D.E.; Hoek, W.

    1977-01-01

    A Harbour Porpoise, Phocoena phocoena, taken from near Shallow Bay, Mackenzie River Delta, Northwest Territories (68°48’ N 136°35’ W) in July 1973 represents a range extension 800 km eastwards from the previous extreme northeastern record on the north Alaskan coast. All 12 Harbour Porpoises so far e

  5. Effects of Mackenzie River Discharge and Bathymetry on Sea Ice in the Beaufort Sea

    Science.gov (United States)

    Nghiem, S. V.; Hall, D. K.; Rigor, I. G; Li, P.; Neumann, G.

    2014-01-01

    Mackenzie River discharge and bathymetry effects on sea ice in the Beaufort Sea are examined in 2012 when Arctic sea ice extent hit a record low. Satellite-derived sea surface temperature revealed warmer waters closer to river mouths. By 5 July 2012, Mackenzie warm waters occupied most of an open water area about 316,000 sq km. Surface temperature in a common open water area increased by 6.5 C between 14 June and 5 July 2012, before and after the river waters broke through a recurrent landfast ice barrier formed over the shallow seafloor offshore the Mackenzie Delta. In 2012, melting by warm river waters was especially effective when the strong Beaufort Gyre fragmented sea ice into unconsolidated floes. The Mackenzie and other large rivers can transport an enormous amount of heat across immense continental watersheds into the Arctic Ocean, constituting a stark contrast to the Antarctic that has no such rivers to affect sea ice.

  6. The delivery of mercury to the Beaufort Sea of the Arctic Ocean by the Mackenzie River.

    Science.gov (United States)

    Leitch, Daniel R; Carrie, Jesse; Lean, David; Macdonald, Robie W; Stern, Gary A; Wang, Feiyue

    2007-02-01

    Very high levels of mercury (Hg) have recently been reported in marine mammals and other higher trophic-level biota in the Mackenzie Delta and Beaufort Sea of the western Arctic Ocean. To quantify the input of Hg (particulate, dissolved and methylated) by the Mackenzie River as a potential source for Hg in the ecosystem, surface water and sediment samples were taken from 79 sites in the lower Mackenzie Basin during three consecutive summers (2003-2005) and analyzed for Hg and methylmercury (MeHg). Intensive studies were also carried out in the Mackenzie Delta during the freshets of 2004 and 2005. Large seasonal and annual variations were found in Hg concentrations in the river, coincident with the variations in water discharge. Increased discharges during spring freshet and during the summers of 2003 and 2005 compared to 2004 were mirrored by higher Hg concentrations. The correlation between Hg concentration and riverflow suggests additional Hg sources during periods of high water, potentially from increased surface inundation and increased bank erosion. The increase in the Hg concentration with increasing water discharge amplifies the annual Hg and MeHg fluxes during high water level years. For the period 2003-2005, the Hg and MeHg fluxes from the Mackenzie River to the Beaufort Sea averaged 2.2 tonnes/yr and 15 kg/yr, respectively, the largest known Hg source to the Beaufort Sea. More than half of the mercury flux occurs during the short spring freshet season which coincides with the period of rapid growth of marine biota. Consequently, the Mackenzie River input potentially provides the major mercury source to marine mammals of the Beaufort Sea. The Hg and MeHg fluxes from the Mackenzie River are expected to further increase with the projected climate warming in the Mackenzie Basin.

  7. Mercury export to the Arctic Ocean from the Mackenzie River, Canada.

    Science.gov (United States)

    Emmerton, Craig A; Graydon, Jennifer A; Gareis, Jolie A L; St Louis, Vincent L; Lesack, Lance F W; Banack, Janelle K A; Hicks, Faye; Nafziger, Jennifer

    2013-07-16

    Circumpolar rivers, including the Mackenzie River in Canada, are sources of the contaminant mercury (Hg) to the Arctic Ocean, but few Hg export studies exist for these rivers. During the 2007-2010 freshet and open water seasons, we collected river water upstream and downstream of the Mackenzie River delta to quantify total mercury (THg) and methylmercury (MeHg) concentrations and export. Upstream of the delta, flow-weighted mean concentrations of bulk THg and MeHg were 14.6 ± 6.2 ng L(-1) and 0.081 ± 0.045 ng L(-1), respectively. Only 11-13% and 44-51% of bulk THg and MeHg export was in the dissolved form. Using concentration-discharge relationships, we calculated bulk THg and MeHg export into the delta of 2300-4200 kg yr(-1) and 15-23 kg yr(-1) over the course of the study. Discharge is not presently known in channels exiting the delta, so we assessed differences in river Hg concentrations upstream and downstream of the delta to estimate its influence on Hg export to the ocean. Bulk THg and MeHg concentrations decreased 19% and 11% through the delta, likely because of particle settling and other processes in the floodplain. These results suggest that northern deltas may be important accumulators of river Hg in their floodplains before export to the Arctic Ocean.

  8. Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system

    Science.gov (United States)

    Vonk, Jorien E.; Giosan, Liviu; Blusztajn, Jerzy; Montlucon, Daniel; Graf Pannatier, Elisabeth; McIntyre, Cameron; Wacker, Lukas; Macdonald, Robie W.; Yunker, Mark B.; Eglinton, Timothy I.

    2015-12-01

    The Mackenzie River in Canada is by far the largest riverine source of sediment and organic carbon (OC) to the Arctic Ocean. Therefore the transport, degradation and burial of OC along the land-to-ocean continuum for this riverine system is important to study both regionally and as a dominant representative of Arctic rivers. Here, we apply sedimentological (grain size, mineral surface area), and organic and inorganic geochemical techniques (%OC, δ13C-OC and Δ14C-OC, 143Nd/144Nd, δ2H and δ18O, major and trace elements) on particulate, bank, channel and lake surface sediments from the Mackenzie Delta, as well as on surface sediments from the Mackenzie shelf in the Beaufort Sea. Our data show a hydrodynamic sorting effect resulting in the accumulation of finer-grained sediments in lake and shelf deposits. A general decrease in organic carbon (OC) to mineral surface area ratios from river-to-sea furthermore suggests a loss of mineral-bound terrestrial OC during transport through the delta and deposition on the shelf. The net isotopic value of the terrestrial OC that is lost en route, derived from relationships between δ13C, OC and surface area, is -28.5‰ for δ13C and -417‰ for Δ14C. We calculated that OC burial efficiencies are around 55%, which are higher (∼20%) than other large river systems such as the Amazon. Old sedimentary OC ages, up to 12 14C-ky, suggest the delivery of both a petrogenic OC source (with an estimated contribution of 19 ± 9%) as well as a pre-aged terrestrial OC source. We calculated the 14C-age of this pre-aged, biogenic, component to be about 6100 yrs, or -501‰, which illustrates that terrestrial OC in the watershed can reside for millennia in soils before being released into the river. Surface sediments in lakes across the delta (n = 20) showed large variability in %OC (0.92-5.7%) and δ13C (-30.7‰ to -23.5‰). High-closure lakes, flooding only at exceptionally high water levels, hold high sedimentary OC contents (>2.5%) and

  9. Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system

    NARCIS (Netherlands)

    Vonk, Jorien E.|info:eu-repo/dai/nl/370832833; Giosan, Liviu; Blusztajn, Jerzy; Montlucon, Daniel; Graf Pannatier, Elisabeth; McIntyre, Cameron; Wacker, Lukas; Macdonald, Robie W.; Yunker, Mark B.; Eglinton, Timothy I.

    2015-01-01

    The Mackenzie River in Canada is by far the largest riverine source of sediment and organic carbon (OC) to the Arctic Ocean. Therefore the transport, degradation and burial of OC along the land-to-ocean continuum for this riverine system is important to study both regionally and as a dominant

  10. Remote sensing the dynamics of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean

    Directory of Open Access Journals (Sweden)

    D. Doxaran

    2012-04-01

    Full Text Available Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. A direct consequence is an increase in Arctic river discharge with an expectation of increased delivery of organic carbon sequestered in high-latitute soils since the last glacial maximum. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed to an operational stage.

    The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM on the Mackenzie River continental shelf (Canadian Arctic Ocean using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC. Robust SPM and POC:SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is validated based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone within which terrigenous SPM is mainly constrained (out of short periods of maximum river outflow. Most of the seaward export of SPM is observed to occur within the west side of the river mouth.

    Future work require the validation of the

  11. Remote sensing the dynamics of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean)

    Science.gov (United States)

    Doxaran, D.; Ehn, J.; Bélanger, S.; Matsuoka, A.; Hooker, S.; Babin, M.

    2012-04-01

    Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. A direct consequence is an increase in Arctic river discharge with an expectation of increased delivery of organic carbon sequestered in high-latitute soils since the last glacial maximum. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed to an operational stage. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC:SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is validated based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone within which terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future work require the validation of the developed SPM regional algorithm based

  12. Coupling hydraulic and hydrological models to simulate the streamflow of a large arctic river: The case of the Mackenzie River

    Science.gov (United States)

    Elshamy, M.; Pietroniro, A.; Wheater, H. S.

    2016-12-01

    Accurate simulation of river streamflow is essential for water resources management and climate change impact studies. Hydrological models often route the streamflow using simple hydrological routing techniques that does not consider the characteristics of river channels or complex morphology present in certain rivers. Yet, for large river systems, as well as for regional and global modelling, routing effects can have a very significant impact on the magnitude of flood peaks and the timing of flows to seas and oceans. In this study, an approach to couple the MESH (Modélisation Environmentale Communautaire-Surface and Hydrology) model, which embeds the Canadian land surface scheme (CLASS), with a one-dimensional river hydraulic model (River-1D) of the main Mackenzie river and the 3 of its main tributaries (Peace, Athabasca, and Slave) is reported. Of particular interest is ensuring the complexity of dealing with the large delta environment where flow reversal and overbank storage is possible and can be a significant part of the water budget. Inflows at designated locations on those rivers are generated by the MESH hydrologic model run at 0.125° spatial resolution and 30 minutes temporal resolution. The one-dimensional hydraulic model simulates the routing along the river in a one-way coupling mode with due consideration to river ice processes including freeze-up and break-up. This approach improves the accuracy of river flow simulations along the main stem of the Mackenzie and its main tributes and allows for studying sediment transport and dynamic events, such as dam breaches or ice jam release and formation events.

  13. Bryophytes from the area drained by the Peel and Mackenzie Rivers, Yukon and Northwest Territories, Canada

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is on bryophytes from the area drained by the Peel and Mackenzie rivers in the Yukon territory of Canada. The distribution and general ecology of 263...

  14. Patterns of hydrogen peroxide among lakes of the Mackenzie Delta, western Canadian Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Febria, C.M. [Simon Fraser Univ., Burnaby, BC (Canada). Dept. of Geography; Toronto Univ., ON (Canada). Dept. of Life Sciences; Lesack, L.F.W. [Simon Fraser Univ., Burnaby, BC (Canada). Dept. of Geography; Simon Fraser Univ., Burnaby, BC (Canada). Dept. of Biological Sciences; Gareis, J.A.L. [Simon Fraser Univ., Burnaby, BC (Canada). Dept. of Biological Sciences; Bothwell, M.L. [Environment Canada, Nanaimo, BC (Canada). Pacific Biological Station

    2006-09-15

    It is anticipated that lakes in the Mackenzie Delta will experience a shift in flood frequency and magnitude as a result of climate change. Stratospheric ozone loss in the circumpolar Arctic is expected to increase levels of ultraviolet radiation. This study represented the first of a series of studies assessing patterns of hydrogen peroxide (H{sub 2}O{sub 2}) produced by interactions of solar radiation and dissolved organic carbon (DOC) in surface waters of circumpolar Arctic river deltas. DOC plays an important role in the optical properties, energy cycling, and photochemical processes of surface waters. H{sub 2}O{sub 2} levels were tracked in 40 lakes during the open water season from the Arctic summer solstice to late summer. Diurnal dynamics of in situ H{sub 2}O{sub 2} were tracked in a pair of lakes with coloured and non-coloured contrasting DOC regimes. Buildup of H{sub 2}O{sub 2} was tracked in experimental microcosms of lake water exposed to manipulated UV levels. Results of the study indicated that H{sub 2}O{sub 2} levels were highest at the solstice and in intermittently flooded lakes. During the solstice, lakes with contrasting DOC regimes showed a cumulative buildup of H{sub 2}O{sub 2} during multiple cloudless days. H{sub 2}O{sub 2} was highest cumulatively in the Delta Lake, with a higher DOC concentration and low in colour. H{sub 2}O{sub 2} buildup in lake water shielded from UVB exposure was not significantly lower than micro-organisms in lake water exposed to full sunlight. Results indicated that the most significant photochemical effects on the seasonal dynamics of aquatic bacteria and other micro-organisms are likely to occur in the first weeks after ice-out. Effects include increased water clarity; an inhibition of biological processes due to both photochemical reactions and direct UVB; and unknown responses by the biological community to the resulting pool of labile, photolyzed DOC substrate that remains for the duration of the open water

  15. Alkane, terpene and polycyclic aromatic hydrocarbon geochemistry of the Mackenzie River and Mackenzie shelf: Riverine contributions to Beaufort Sea coastal sediment

    Science.gov (United States)

    Yunker, Mark B.; Macdonald, Robie W.; Cretney, Walter J.; Fowler, Brian R.; McLaughlin, Fiona A.

    1993-07-01

    To study the largest source of river sediment to the Arctic Ocean, we have collected suspended particulates from the Mackenzie River in all seasons and sediments from the Mackenzie shelf between the river mouth and the shelf edge. These samples have been analyzed for alkanes, triterpenes and polycyclic aromatic hydrocarbons (PAHs). We found that naturally occurring hydrocarbons predominate in the river and on the shelf. These hydrocarbons include biogenic alkanes and triterpenes with a higher plant/peat origin, diagenetic PAHs from peat and plant detritus, petrogenic alkanes, triterpenes and PAHs from oil seeps and/or bitumens and combustion PAHs that are likely relict in peat deposits. Because these components vary independently, the season is found to strongly influence the concentration and composition of hydrocarbons in the Mackenzie River. While essentially the same pattern of alkanes, diagenetic hopanes and alkyl PAHs is observed in all river and most shelf sediment samples, alkane and triterpene concentration variations are strongly linked to the relative amount of higher plant/peat material. Polycyclic aromatic hydrocarbon molecular-mass profiles also appear to be tied primarily to varying proportions of peat, with an additional petrogenic component which is most likely associated with lithic material mobilized by the Mackenzie River at freshet. Consistent with the general lack of alkyl PAHs in peat, the higher PAHs found in the river are probably derived from forest and tundra fires. A few anthropogenic/pyrogenic compounds are manifest only at the shelf edge, probably due to a weakening of the river influence. We take this observation of pyrogenic PAHs and the pronounced source differences between two sediment samples collected at the shelf edge as evidence of a transition from dominance by the Mackenzie River to the geochemistry prevalent in Arctic regions far removed from major rivers.

  16. Sharing Remote and Local Information for Tracking Spring Breakup in the Mackenzie Delta and Beaufort Sea

    Science.gov (United States)

    Forbes, D. L.; Whalen, D.; Fraser, P.

    2015-12-01

    The Mackenzie Delta is the second largest on the Arctic Ocean, covering 13 000 km2. The annual flood regime in the delta is dominated by the spring snowmelt freshet and associated ice breakup, as water from the south arrives in the ice-covered delta and spreads over bottomfast and adjacent floating sea ice at the delta front. The complex processes of water-ice interaction, flow partitioning, and overbank flooding to replenish waters in 43 000 delta lakes threaten community, transportation, subsistence, and energy infrastructure in the delta. The annual breakup season is a time of rejuvenation, excitement, and anxiety for delta residents and stakeholders. To track the progress of breakup and meet the need for knowledge dissemination to the local communities, a Mackenzie-Beaufort breakup newsletter has been produced by Natural Resources Canada on a quasi-daily basis during the May-June spring flood season for 10 years, and distributed to an e-mail list that grew to over 300 subscribers. This provides near real-time tracking of water levels and breakup using on-line gauges (Environment Canada), daily MODIS satellite imagery (NASA), Landsat imagery (USGS) and intermittent radar imagery (various sources). In earlier years, information was also supplied from field programs operating in the delta during breakup, but changing priorities and funding have reduced the number of outside researchers present during these critical weeks. Meanwhile the number of local contributors has grown, providing observations and photographs to share with the local, regional and global readership. In this way the newsletter evolved into a two-way communication tool and community portal. The newsletter is a chronicle of each breakup season and a key resource for territorial and municipal managers, subsistence organizations, and emergency response agencies, with routine requests for specific imagery in areas of concern. With the completion of 10 years under the present model, we are exploring

  17. Genetics, recruitment, and migration patterns of Arctic Cisco (Coregonus autumnalis) in the Colville River, Alaska and Mackenzie River, Canada

    Science.gov (United States)

    Zimmerman, Christian E.; Ramey, Andy M.; Turner, S.; Mueter, Franz J.; Murphy, S.; Nielsen, Jennifer L.

    2013-01-01

    Arctic cisco Coregonus autumnalis have a complex anadromous life history, many aspects of which remain poorly understood. Some life history traits of Arctic cisco from the Colville River, Alaska, and Mackenzie River basin, Canada, were investigated using molecular genetics, harvest data, and otolith microchemistry. The Mackenzie hypothesis, which suggests that Arctic cisco found in Alaskan waters originate from the Mackenzie River system, was tested using 11 microsatellite loci and a single mitochondrial DNA gene. No genetic differentiation was found among sample collections from the Colville River and the Mackenzie River system using molecular markers (P > 0.19 in all comparisons). Model-based clustering methods also supported genetic admixture between sample collections from the Colville River and Mackenzie River basin. A reanalysis of recruitment patterns to Alaska, which included data from recent warm periods and suspected changes in atmospheric circulation patterns, still finds that recruitment is correlated to wind conditions. Otolith microchemistry (Sr/Ca ratios) confirmed repeated, annual movements of Arctic cisco between low-salinity habitats in winter and marine waters in summer.

  18. From Natural to Design River Deltas

    Science.gov (United States)

    Giosan, Liviu

    2016-04-01

    Productive and biologically diverse, deltaic lowlands attracted humans since prehistory and may have spurred the emergence of the first urban civilizations. Deltas continued to be an important nexus for economic development across the world and are currently home for over half a billion people. But recently, under the double whammy of sea level rise and inland sediment capture behind dams, they have become the most threatened coastal landscape. Here I will address several deceptively simple questions to sketch some unexpected answers using example deltas from across the world from the Arctic to the Tropics, from the Danube to the Indus, Mississippi to Godavari and Krishna, Mackenzie to Yukon. What is a river delta? What is natural and what is not in a river delta? Are the geological and human histories of a delta important for its current management? Is maintaining a delta the same to building a new one? Can we design better deltas than Nature? These answers help us see clearly that survival of deltas in the next century depends on human intervention and is neither assured nor simple to address or universally applicable. Empirical observations on the hydrology, geology, biology and biochemistry of deltas are significantly lagging behind modeling capabilities endangering the applicability of numerical-based reconstruction solutions and need to be ramped up significantly and rapidly across the world.

  19. An ECOMAG-based Regional Hydrological Model for the Mackenzie River basin

    Science.gov (United States)

    Motovilov, Yury; Kalugin, Andrey; Gelfan, Alexander

    2017-04-01

    A physically-based distributed model of runoff generation has been developed for the Mackenzie River basin (the catchment area is 1 660 000 km2). The model is based on the ECOMAG (ECOlogical Model for Applied Geophysics) hydrological modeling platform and describes processes of interception of rainfall/snowfall by the canopy, snow accumulation and melt, soil freezing and thawing, water infiltration into unfrozen and frozen soil, evapotranspiration, thermal and water regime of soil, overland, subsurface and ground flow, flow routing through a channel network accounting for flow regulation by lakes and reservoirs. The governing model's equations are derived from integration of the basic hydro- and thermodynamics equations of water and heat vertical transfer in snowpack, frozen/unfrozen soil, horizontal water flow under and over catchment slopes, etc. The Mackenzie basin's schematization was performed on the basis of the global DEM data (1-km resolution) from the HYDRO1K database of the U.S. Geological Survey. Most of the model parameters are physically meaningful and derived through the global datasets of the basin characteristics: FAO/IIASA Harmonized World Soil Database, USGS EROS Global Land Cover Characteristics project, etc. The 0.5ox0.5o WATCH reanalysis daily precipitation, air temperature and air humidity data were used as the model input for the period of 1971-2002. The daily discharge data provided by the Water Survey of Canada for 10 streamflow gauges, which are located at the Mackenzie River and the main tributaries (Peel River, Great Bear River, Liard River, Slave River and Athabasca River), were used for calibration (1991-2001) and validation (1971-1990) of the model. The gauges' catchment areas vary from 70600 km2 (Peel River above Fort Mopherson) to 1 660 000 km2 (Mackenzie River at Arctic Red River). The model demonstrated satisfactory performance in terms of Nash-and Sutcliffe efficiency (NSE(daily)0.60 and NSE(monthly)0.70) and percent bias

  20. Optical Characterisation of Suspended Particles in the Mackenzie River Plume (Canadian Arctic Ocean) and Implications for Ocean Colour Remote Sensing

    Science.gov (United States)

    Doxaran, D.; Ehn, J.; Belanger, S.; Matsuoka, A.; Hooker, S.; Babin, M.

    2012-01-01

    Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC : SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future

  1. Optical characterisation of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean and implications for ocean colour remote sensing

    Directory of Open Access Journals (Sweden)

    D. Doxaran

    2012-08-01

    Full Text Available Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational.

    The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM on the Mackenzie River continental shelf (Canadian Arctic Ocean using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC. Robust SPM and POC : SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow. Most of the seaward export of SPM is observed to occur within the west side of

  2. Optical characterisation of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean) and implications for ocean colour remote sensing

    Science.gov (United States)

    Doxaran, D.; Ehn, J.; Bélanger, S.; Matsuoka, A.; Hooker, S.; Babin, M.

    2012-08-01

    Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC : SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future

  3. Scientific results from JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well, Mackenzie Delta, Northwest Territories, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Dallimore, S.R. [ed.] [Geological Survey of Canada, Ottawa, ON (Canada); Uchida, T. [ed.] [JAPEX Research Center, Chiba (Japan); Collett, T.S. [ed.] [United States Geological Survey, Denver, CO (United States)

    1999-10-01

    A general overview was presented of a joint research project involving Canada, the United States and Japan. The project involved the drilling of the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well to examine the occurrence of natural gas hydrate beneath permafrost. The 1150 m deep gas hydrate well, which is located on the northeastern edge of the Mackenzie Delta, Northwest Territories was completed in March 1998. This book presents the scientific results from the well program. It is meant to assess regional issues related to gas hydrate occurrences in the Mackenzie Delta area. An operations overview of the project was presented along with the regional geology, gas hydrate setting, and the ground-thermal conditions of the Mackenzie Delta region. 19 papers were also included which provided a comprehensive review of the core data collected in the well. The studies were grouped into the following subjects: (1) geology and biostratigraphy, (2) geophysical properties, (3) geochemistry, (4) gas hydrate characterization, and (5) downhole geophysics. One well log and three maps were included with this bulletin. refs., tabs., figs.

  4. A 50% increase in the amount of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean over the last 10 years

    Directory of Open Access Journals (Sweden)

    D. Doxaran

    2015-01-01

    Full Text Available Global warming has a significant impact at the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia. The recent increase in air temperature has resulted in increased precipitations along the drainage basins of Arctic Rivers. It has also directly impacted land and seawater temperatures with the consequence of melting the permafrost and sea-ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25% since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which was sequestered as frozen since the last glacial maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems. In this study we use 11 years of ocean-colour satellite data and field observations collected in 2009 to estimate the amount of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean. Our results show that during the summer period the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33%, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50% increase in the particulate (terrestrial suspended particles and organic carbon export from the Mackenzie River into the Beaufort Sea.

  5. A 50 % increase in the mass of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

    Science.gov (United States)

    Doxaran, D.; Devred, E.; Babin, M.

    2015-06-01

    Global warming has a significant impact on the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitation along the drainage basins of Arctic rivers. It has also directly impacted land and seawater temperatures with the consequence of melting permafrost and sea ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25% since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which has been sequestered in a frozen state since the Last Glacial Maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems. In this study we use 11 years of ocean color satellite data and field observations collected in 2009 to estimate the mass of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean). Our results show that during the summer period, the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33%, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50% increase in the particulate (terrestrial suspended particles and organic carbon) export from the Mackenzie River into the Beaufort Sea.

  6. A 50% increase in the amount of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

    Science.gov (United States)

    Doxaran, D.; Devred, E.; Babin, M.

    2015-01-01

    Global warming has a significant impact at the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitations along the drainage basins of Arctic Rivers. It has also directly impacted land and seawater temperatures with the consequence of melting the permafrost and sea-ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25% since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which was sequestered as frozen since the last glacial maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems. In this study we use 11 years of ocean-colour satellite data and field observations collected in 2009 to estimate the amount of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean). Our results show that during the summer period the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33%, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50% increase in the particulate (terrestrial suspended particles and organic carbon) export from the Mackenzie River into the Beaufort Sea.

  7. Cooperative and adaptive transboundary water governance in Canada's Mackenzie River Basin: status and prospects

    Directory of Open Access Journals (Sweden)

    Michelle Morris

    2016-03-01

    Full Text Available Canada's Mackenzie River Basin (MRB is one of the largest relatively pristine ecosystems in North America. Home to indigenous peoples for millennia, the basin is also the site of increasing resource development, notably fossil fuels, hydroelectric power resources, minerals, and forests. Three provinces, three territories, the Canadian federal government, and Aboriginal governments (under Canada's constitution, indigenous peoples are referred to as "Aboriginal" have responsibilities for water in the basin, making the MRB a significant setting for cooperative, transboundary water governance. A framework agreement that provides broad principles and establishes a river basin organization, the MRB Board, has been in place since 1997. However, significant progress on completing bilateral agreements under the 1997 Mackenzie River Basin Transboundary Waters Master Agreement has only occurred since 2010. We considered the performance of the MRB Board relative to its coordination function, accountability, legitimacy, and overall environmental effectiveness. This allowed us to address the extent to which governance based on river basin boundaries, a bioregional approach, could contribute to adaptive governance in the MRB. Insights were based on analysis of key documents and published studies, 19 key informant interviews, and additional interactions with parties involved in basin governance. We found that the MRB Board's composition, its lack of funding and staffing, and the unwillingness of the governments to empower it to play the role envisioned in the Master Agreement mean that as constituted, the board faces challenges in implementing a basin-wide vision. This appears to be by design. The MRB governments have instead used the bilateral agreements under the Master Agreement as the primary mechanism through which transboundary governance will occur. A commitment to coordinating across the bilateral agreements is needed to enhance the prospects for

  8. Monitoring ice break-up on the Mackenzie River using MODIS data

    Directory of Open Access Journals (Sweden)

    P. Muhammad

    2015-05-01

    Full Text Available This study involves the analysis of Moderate Resolution Imaging Spectroradiometer (MODIS Level 3 500 m snow products (MOD/MYD10A1, complemented with 250 m Level 1B data (MOD/MYD02QKM, to monitor ice cover during the break-up period on the Mackenzie River, Canada. Results from the analysis of data for 13 ice seasons (2001–2013 show that first day ice-off dates are observed between days of year (DOY 115–125 and end DOY 145–155, resulting in average melt durations of about 30–40 days. Floating ice transported northbound could therefore generate multiple periods of ice-on and ice-off observations at the same geographic location. During the ice break-up period, ice melt was initiated by in situ (thermodynamic melt over the drainage basin especially between 61–61.8° N (75–300 km. However, ice break-up process north of 61.8° N was more dynamically driven. Furthermore, years with earlier initiation of the ice break-up period correlated with above normal air temperatures and precipitation, whereas later ice break-up period was correlated with below normal precipitation and air temperatures. MODIS observations revealed that ice runs were largely influenced by channel morphology (islands and bars, confluences and channel constriction. It is concluded that the numerous MODIS daily overpasses possible with the Terra and Aqua polar orbiting satellites, provide a powerful means for monitoring ice break-up processes at multiple geographical locations simultaneously along the Mackenzie River.

  9. Spring-Summer Temperatures Since AD 1780 Reconstructed from Stable Oxygen Isotope Ratios in White Spruce Tree-Rings from the Mackenzie Delta, Northwestern Canada

    Science.gov (United States)

    Porter, Trevor J.; Pisaric, Michael F. J.; Field, Robert D.; Kokelj, Steven V.; Edwards, Thomas W. D.; deMontigny, Peter; Healy, Richard; LeGrande, Allegra N.

    2013-01-01

    High-latitude delta(exp 18)O archives deriving from meteoric water (e.g., tree-rings and ice-cores) can provide valuable information on past temperature variability, but stationarity of temperature signals in these archives depends on the stability of moisture source/trajectory and precipitation seasonality, both of which can be affected by atmospheric circulation changes. A tree-ring delta(exp 18)O record (AD 1780-2003) from the Mackenzie Delta is evaluated as a temperature proxy based on linear regression diagnostics. The primary source of moisture for this region is the North Pacific and, thus, North Pacific atmospheric circulation variability could potentially affect the tree-ring delta(exp 18)O-temperature signal. Over the instrumental period (AD 1892-2003), tree-ring delta(exp 18)O explained 29% of interannual variability in April-July minimum temperatures, and the explained variability increases substantially at lower-frequencies. A split-period calibration/verification analysis found the delta(exp 18)O-temperature relation was time-stable, which supported a temperature reconstruction back to AD 1780. The stability of the delta(exp 18)O-temperature signal indirectly implies the study region is insensitive to North Pacific circulation effects, since North Pacific circulation was not constant over the calibration period. Simulations from the NASA-GISS ModelE isotope-enabled general circulation model confirm that meteoric delta(exp 18)O and precipitation seasonality in the study region are likely insensitive to North Pacific circulation effects, highlighting the paleoclimatic value of tree-ring and possibly other delta(exp 18)O records from this region. Our delta(exp 18)O-based temperature reconstruction is the first of its kind in northwestern North America, and one of few worldwide, and provides a long-term context for evaluating recent climate warming in the Mackenzie Delta region.

  10. A Combination of Different Synthetic Aperture Radar (SAR) Techniques for Bottom-Fast Ice and Permafrost Monitoring in Canadian Polar Region (Mackenzie Delta)

    Science.gov (United States)

    Alasset, P.; Parsons, G.; Yue, B.; Chamberland, J.; Mulvie, J.

    2009-12-01

    The Mackenzie Delta is a unique region in the Canadian North which is rich in hydrocarbons and supports a fragile ecosystem. A need exists to define nominal remote coastal conditions prior to hydrocarbon extraction and to assist in monitoring conditions once the extraction will be underway. Near shore the formation of Bottom-Fast Ice (BFI) plays an important role in the region’s seasonal environmental changes and in the understanding of arctic coastal environmental and geophysical control processes. BFI is ice that has frozen to the seabed in shallow sea water and forms in areas where the sea water is shallow. These regions control permafrost distribution, spring overflow and potential strudel scours - holes in the frozen seafloor from flowing fresh water in rivers and streams during spring in the Beaufort Sea - and influence channel mouth constraints and early breakup season flood routing. BFI has been studied by generating D-InSAR (Differential SAR Interferometry) coherence maps during the winter of 2007-2008 and 2008-2009 using a combination of SAR image pairs from the TerraSAR-X space borne sensor. The results derived from these data were compared to results obtained from ALOS-PALSAR and RADARSAT-2 using advanced polarimetric techniques for BFI delineation. All coherence maps of the winter 2008-2009 data were assembled and compiled to demonstrate seasonal changes throughout the winter. The results of these analyses indicate that deriving coherence maps from repeat-pass data generates a product that is indicative of BFI regions; though relying on an entirely different land characteristic than polarimetric BFI delineation (e.g. ground stability vs. dielectric constants). Through the use of various polarimetric channels, a good discrimination between BFI regions and ice-covered land regions has been noted in the past. With specialised analysts, it is possible to reasonably outline BFI regions from these polarimetric datasets. Additional to these standard

  11. Numerical studies of gas production from several CH4 hydrate zones at the Mallik site, Mackenzie Delta, Canada

    Science.gov (United States)

    Moridis, G.J.; Collett, T.S.; Dallimore, S.R.; Satoh, T.; Hancock, S.; Weatherill, B.

    2004-01-01

    The Mallik site represents an onshore permafrost-associated gas hydrate accumulation in the Mackenzie Delta, Northwest Territories, Canada. A gas hydrate research well was drilled at the site in 1998. The objective of this study is the analysis of various gas production scenarios from five methane hydrate-bearing zones at the Mallik site. In Zone #1, numerical simulations using the EOSHYDR2 model indicated that gas production from hydrates at the Mallik site was possible by depressurizing a thin free gas zone at the base of the hydrate stability field. Horizontal wells appeared to have a slight advantage over vertical wells, while multiwell systems involving a combination of depressurization and thermal stimulation offered superior performance, especially when a hot noncondensible gas was injected. Zone #2, which involved a gas hydrate layer with an underlying aquifer, could yield significant amounts of gas originating entirely from gas hydrates, the volumes of which increased with the production rate. However, large amounts of water were also produced. Zones #3, #4 and #5 were lithologically isolated gas hydrate-bearing deposits with no underlying zones of mobile gas or water. In these zones, thermal stimulation by circulating hot water in the well was used to induce dissociation. Sensitivity studies indicated that the methane release from the hydrate accumulations increased with the gas hydrate saturation, the initial formation temperature, the temperature of the circulating water in the well, and the formation thermal conductivity. Methane production appears to be less sensitive to the specific heat of the rock and of the hydrate, and to the permeability of the formation. ?? 2004 Published by Elsevier B.V.

  12. Yellow River Delta Faces a Historic Opportunity

    Institute of Scientific and Technical Information of China (English)

    Li Zhen

    2010-01-01

    @@ China's State Council has endorsed the Development Plan of an Efficient Eco-Economic Zone at Yellow River Delta. The plan is meant to create a more ecologically sustainable economic zone along the river delta.

  13. Yellow River Delta Faces a Historic Opportunity

    Institute of Scientific and Technical Information of China (English)

    Li Zhen

    2011-01-01

    @@ China's State Council has endorsed the Development Plan of an Efficient Eco-Economic Zone at Yellow River Delta.The plan is meant to create a more ecologically sustainable economic zone along the river delta.

  14. On the modelling of river delta formation

    NARCIS (Netherlands)

    Geleynse, N.

    2013-01-01

    This thesis presents approaches to the modelling of river delta formation. In particular, it provides results of numerical stratigraphic-morphodynamic modelling of river delta formation under various environmental forcings.

  15. Sensitivity of Arctic Permafrost Carbon in the Mackenzie River Basin: A substrate addition and incubation experiment

    Science.gov (United States)

    Hedgpeth, A.; Beilman, D.; Crow, S. E.

    2014-12-01

    Arctic soil organic matter (SOM) mineralization processes are fundamental to the functioning of high latitude soils in relation to nutrients, stability, and feedbacks to atmospheric CO2 and climate. The arctic permafrost zone covers 25% of the northern hemisphere and contains 1672Pg of soil carbon (C). 88% of this C currently resides in frozen soils that are vulnerable to environmental change. For instance, arctic growing seasons may be lengthened, resulting in an increase in plant productivity and rate of below ground labile C inputs as root exudates. Understanding controls on Arctic SOM dynamics requires recognition that labile C inputs have the potential to significantly affect mineralization of previously stable SOM, also known as 'priming effects'. We conducted a substrate addition incubation experiment to quantify and compare respiration in highly organic (42-48 %C) permafrost soils along a north-south transect in western Canada. Near surface soils (10-20 cm) were collected from permafrost peatland sites in the Mackenzie River Basin from 69.2-62.6°N. The surface soils are fairly young (Δ14C values > -140.0) and can be assumed to contain relatively reactive soil carbon. To assess whether addition of labile substrate alters SOM decomposition dynamics, 4.77-11.75 g of permafrost soil were spiked with 0.5 mg D-glucose g-1 soil and incubated at 5°C. A mass balance approach was used to determin substrate-induced respiration and preliminary results suggest a potential for positive priming in these C-rich soils. Baseline respiration rates from the three sites were similar (0.067-0.263 mg CO2 g-1 soil C) yet show some site-specific trends. The rate at which added substrate was utilized within these soils suggests that other factors besides temperature and soil C content are controlling substrate consumption and its effect on SOM decomposition. Microbial activity can be stimulated by substrate addition to such an extent that SOM turnover is enhanced, suggesting that

  16. Reflections on Development Strategy of Pearl River Delta: In Comparison with Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>1. A comparison between Pearl River Delta and Yangtze River Delta 1.1 Basic conditions 1.1.1 Location, area and scope Located in the southeast of Guangdong Province, the Pearl River Delta (PRD) as an economic zone is a compound delta

  17. Basin-Scale Exports vs. Coastal Delivery of Carbon, Nutrients and Particulates Above and Below Arctic River Deltas

    Science.gov (United States)

    Striegl, R. G.; Tank, S. E.; Weeks, G.; Holmes, R. M.; McClelland, J. W.

    2014-12-01

    Recent studies have substantially improved our understanding of water, sediment and materials exports by arctic rivers. Seasonality of exports, particularly during the spring freshet, is better quantified, as are the inland sources of water and sediment discharge and the source and chemical character of other material exports, including carbon and nutrients. Measurements on small rivers discharging directly to the Arctic Ocean and lacking complex deltas can accurately quantify local inputs to coastal regions. However, the majority of hydrologic inputs to the Arctic Ocean derive from 6 major Eurasian and North American rivers. Water, sediment, and chemical exports from these rivers are typically measured above head of tide, far inland, and commonly above large river deltas. These deltas settle particles and provide favorable environments for deposition, storage, and biogeochemical consumption, production, and transformation of aquatic carbon and nutrients. Consequently, basin exports measured above river deltas likely misrepresent actual delivery to coastal regions. In addition to accumulating sediment, observed and modeled arctic delta effects include enrichment of the organic content of suspended solids, increased dissolved organic carbon and nitrogen (DOC; DON) concentration, decreased inorganic nutrient concentration, and settling and likely increased bioavailability of particle associated contaminants, such as mercury. Increased DOC concentration in the Mackenzie River delta has also been associated with a change in DOC quality, with increased potential for biodegradation of DOC and decreased potential for photodegradation of DOC from head of tide to within the delta. For the most part, assessments of differences between head of tide basin exports and coastal delivery tend to be qualitative rather than quantitative, largely because of difficulties quantifying tidally affected flow. This points to the need to resolve data gaps, improve quantitative assessments

  18. Response of River Discharge to Changing Climate Over the Past Millennium in the Upper Mackenzie Basin: Implications for Water Resource Management

    Science.gov (United States)

    Wolfe, B. B.; Hall, R. I.; Edwards, T. W.; Jarvis, S. R.; Sinnatamby, R. N.; Yi, Y.; Johnston, J. W.

    2009-05-01

    Runoff generated from high elevations is the primary source of freshwater for western North America, yet this critical resource is managed on the basis of short instrumental records that encompass an insufficient range of climatic conditions. Like other streams that drain this part of the continent and flow across the northern Great Plains, where seasonal and extended intervals of water deficit are a natural element of the landscape, the Peace and Athabasca rivers provide water that is crucial for societal needs. Climate variability and rapidly increasing industrial development are, however, raising concerns over the future availability of water resources for continued economic growth in these watersheds and to maintain the integrity of aquatic ecosystems, including the Peace-Athabasca Delta (PAD). This is particularly acute for the Athabasca River because the Alberta oil sands industry remains dependent on its water for bitumen extraction. Here we report the effects of climate change over the past 1000 years on river discharge in the upper Mackenzie River system based on paleoenvironmental information from the PAD and Lake Athabasca. The delta landscape responds to hydroclimatic changes with marked variability, capturing systematic changes in ice-jam flood frequency and perched basin water balance. Lake Athabasca level appears to directly monitor overall water availability with the highest levels occurring in concert with maximum glacier extent during the Little Ice Age, and the lowest during the 11th century prior to medieval glacier expansion. Recent climate-driven hydrological change appears to be on a trajectory to even lower levels as high-elevation snow and glacier meltwater contributions both continue to decline. The temporal perspective offered by these paleohydrological reconstructions indicates that climatic changes over the past millennium have led to characteristic responses in the quantity and seasonality of streamflow generated from the hydrographic

  19. Neural network analysis of crosshole tomographic images: The seismic signature of gas hydrate bearing sediments in the Mackenzie Delta (NW Canada)

    Science.gov (United States)

    Bauer, K.; Pratt, R. G.; Haberland, C.; Weber, M.

    2008-10-01

    Crosshole seismic experiments were conducted to study the in-situ properties of gas hydrate bearing sediments (GHBS) in the Mackenzie Delta (NW Canada). Seismic tomography provided images of P velocity, anisotropy, and attenuation. Self-organizing maps (SOM) are powerful neural network techniques to classify and interpret multi-attribute data sets. The coincident tomographic images are translated to a set of data vectors in order to train a Kohonen layer. The total gradient of the model vectors is determined for the trained SOM and a watershed segmentation algorithm is used to visualize and map the lithological clusters with well-defined seismic signatures. Application to the Mallik data reveals four major litho-types: (1) GHBS, (2) sands, (3) shale/coal interlayering, and (4) silt. The signature of seismic P wave characteristics distinguished for the GHBS (high velocities, strong anisotropy and attenuation) is new and can be used for new exploration strategies to map and quantify gas hydrates.

  20. Jiaxing: Delicacy of the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    WUXINYI; WANGNAN

    2004-01-01

    THE yangtze River Delta,where the Yangtzc River crosses China's east coast,has one of the country's most dynamic economies.In 1976Jcan Gottmann.a french geographer,called shanghai and its neighboring Yangtze River Delta the world's "sixth largest megalopolis." The Yangtze River Delta has 15 cities. Its territory accounts for one percent of China's total, 5.8 percent of hthe population, and 19.5 percent of the national GDP.In terms of both aggregate economy and growth speed, the Delta currently leads China and could likely be the "enginc" of the world's future economic growth. Located at the juncition of Shanghai Jiangsu and Zhejiang, Jiaxing City holds a central economic belt. It is within 100 kilometers of Shanghai, Hangzhou and Suzhou. In 200 and 2003, Jiaxing's GDP growth rate was first in Zhejiang Province and second among the 1.5 Delta cities.

  1. Proterozoic Carbonate Lithofacies Control the Distribution of Sulphides at the Gayna River Zn-Pb Camp, Mackenzie Mountains, NWT

    Science.gov (United States)

    Turner, E. C.

    2009-05-01

    Zn-Pb deposits at Gayna River, NWT are predominantly concentrated in the informal 'Grainstone formation', a dolostone of the early Neoproterozoic Little Dal Group (Mackenzie Mountains Supergroup). Previous work showed that the mineralisation (inferred 50 Mt combined from numerous zones; 5 percent combined Zn+Pb) is fracture-controlled and spatially associated with giant stromatolite reefs (500 m thick) of the underlying formation. The rheologically brittle, uncompactable and hydrologically tight reef masses are enclosed by coeval, compacted shale and deep-water limestone. A long and complex history of reef growth controlled by sea-level change resulted in a distinctive reef morphology that includes a sharp right-angle at all reef-top margins, where heterogeneous, off-reef limestone, shale and dolostone abut the rigid, lithologically homogeneous reefs. These zones of abrupt lateral facies change, between uncompactable reef and ductile, layered off-reef strata, represent the structurally weakest points in the system, where, during even subtle later tectonic events, stress would be preferentially accommodated. Brittle deformation of competent carbonate layers in this inflection zone in response to stress produced fracture haloes around reef-tops, which were then occluded by Zn-Pb sulphides. Abrupt competence contrasts appear to be necessary for the production of fractures that control the locations of sulphides at Gayna River. The dominant fractures in the Gayna River camp are those associated with reef- tops. The plan shape and location of buried reef-tops are probably the most critical controls on the distribution of hitherto undiscovered sulphide masses in the subsurface. Careful mapping of those depositional lithofacies that are characteristic of near-reef environments and of subtle, compaction-related dips in appropriate stratigraphic levels may provide vectors to as-yet unrecognised subsurface reef-margin zones favourable for Zn-Pb mineralisation. Structures and

  2. Proceedings of the GNWT Beaufort-Delta regional workshop on the social impacts of the Mackenzie Valley Gas Project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This workshop provided a forum for communities and governments to discuss the potential social impacts of the Mackenzie Gas Project (MGP). The purpose of the workshop was to ensure that communities will have the capacity to manage the social impacts of the pipeline and related exploration and development activities in the future. The workshop was organized around key questions that solicited community perspectives on social impacts from various governmental agencies. The construction of the MGP will result in increased needs for housing, medical services, and social work programs in affected communities. It is expected that construction camps located near communities will create the need for additional drug abuse, and domestic violence counsellors. Inventories of social programs and baseline profiles of social conditions were presented. Local plans for managing impacts during construction of the MGP were discussed, and potential mitigation efforts were reviewed. Issues related to funding and social assistance were also examined. It was concluded that the workshop will serve as the basis for future collaboration and cooperation amongst the various levels of government in managing the social impacts of the pipeline. Six presentations were given at the workshop. refs., tabs., figs.

  3. Evolution of Modern Yellow River Delta Coast

    Institute of Scientific and Technical Information of China (English)

    尹延鸿; 周永青; 丁东

    2004-01-01

    This paper deals with the development and evolution of modem Yellow River delta and the erosion or deposition rates of its different sections. In June, 1996,Yellow Rivers terminal course was artificially turned eastwards to empty into the sea and then the 11th lobe of the modern Yellow River delta began to form. This course change may mark the beginning of the 3rd subdelta formation. As a result of that, the Yellow River delta advances towards east by north with the 1st, 2nd and 3rd subdeltas arranged in succession. Coast zone in the deltaic area is divided into 7 different sections according to their different erosion or deposition rates: the relatively stable section from Dakou River to Shunjiang Stream, the weakly retreating section from Shun jiang Stream to the Tiaohe River mouth, the strongly retreating section from the Tiaohe River mouth to the station 106, the artificially stable section due to stone dam protection from the station 106 to Gudong Oilfield, the strong deposition section from Gudong Oilfield to Dawenliu Haipu, the weakly deposition section from Dawenliu Haipu to the Zimai Stream mouth, and the stable section from the Zimai Stream mouth to the Jiaolai River mouth. It is predicted that the erosion and deposition situations of the sections will nearly remain the same in 10 years, but the retreating and silting-up rates will tend to become slower gradually. Human activities have an evident influence on the changes of the coastline.

  4. Remote Sensing of River Delta Inundation: Exploiting the Potential of Coarse Spatial Resolution, Temporally-Dense MODIS Time Series

    Directory of Open Access Journals (Sweden)

    Claudia Kuenzer

    2015-07-01

    Full Text Available River deltas belong to the most densely settled places on earth. Although they only account for 5% of the global land surface, over 550 million people live in deltas. These preferred livelihood locations, which feature flat terrain, fertile alluvial soils, access to fluvial and marine resources, a rich wetland biodiversity and other advantages are, however, threatened by numerous internal and external processes. Socio-economic development, urbanization, climate change induced sea level rise, as well as flood pulse changes due to upstream water diversion all lead to changes in these highly dynamic systems. A thorough understanding of a river delta’s general setting and intra-annual as well as long-term dynamic is therefore crucial for an informed management of natural resources. Here, remote sensing can play a key role in analyzing and monitoring these vast areas at a global scale. The goal of this study is to demonstrate the potential of intra-annual time series analyses at dense temporal, but coarse spatial resolution for inundation characterization in five river deltas located in four different countries. Based on 250 m MODIS reflectance data we analyze inundation dynamics in four densely populated Asian river deltas—namely the Yellow River Delta (China, the Mekong Delta (Vietnam, the Irrawaddy Delta (Myanmar, and the Ganges-Brahmaputra (Bangladesh, India—as well as one very contrasting delta: the nearly uninhabited polar Mackenzie Delta Region in northwestern Canada for the complete time span of one year (2013. A complex processing chain of water surface derivation on a daily basis allows the generation of intra-annual time series, which indicate inundation duration in each of the deltas. Our analyses depict distinct inundation patterns within each of the deltas, which can be attributed to processes such as overland flooding, irrigation agriculture, aquaculture, or snowmelt and thermokarst processes. Clear differences between mid

  5. The Changing Cold Regions Network: Atmospheric, Cryospheric, Ecological and Hydrological Change in the Saskatchewan and Mackenzie River Basins, Canada (Invited)

    Science.gov (United States)

    Wheater, H. S.; DeBeer, C.

    2013-12-01

    The cold interior of Northwestern Canada has one of the world's most extreme and varied climates and, as with other regions across the Arctic, is experiencing rapid environmental change. The Changing Cold Regions Network (CCRN) is a new Canadian research network devoted to addressing key challenges and globally-important issues facing the Arctic by improving the understanding of past and ongoing changes in climate, land, vegetation, and water, and predicting their future integrated responses, with a geographic focus on the Saskatchewan and Mackenzie River Basins. The network is funded for 5 years (2013-18) by the Natural Sciences and Engineering Research Council of Canada, and combines the unique expertise of 36 Canadian scientists representing 8 universities and 4 Federal government agencies, as well as 15 international researchers from the United States, China, Australia, the UK, France, and Germany. The network will also involve the World Climate Research Programme, NASA, the Canadian Space Agency, and the National Center for Atmospheric Research. CCRN will integrate existing and new experimental data with modelling and remote sensing products to understand, diagnose and predict changing land, water and climate, and their interactions and feedbacks, for Northwestern Canada's cold interior. It will use a network of world class observatories to study the detailed connections among changing climate, ecosystems and water in the permafrost regions of the Sub-arctic, the Boreal Forest, the Western Cordillera, and the Prairies. Specifically, the network will: 1. Document and evaluate observed Earth system change, including hydrological, ecological, cryospheric and atmospheric components over a range of scales from local observatories to biome and regional scales; 2. Improve understanding and diagnosis of local-scale change by developing new and integrative knowledge of Earth system processes, incorporating these processes into a suite of process-based integrative

  6. Passive acoustic derived bubble flux and applications to natural gas seepage in the Mackenzie Delta, NWT, Canada and Coal Oil Point, CA

    Science.gov (United States)

    Culling, D.; Leifer, I.; Dallimore, S.; Alcala, K.

    2012-12-01

    Minnaert equation predicts. Furthermore, bubbles from a cohesive media escaped in pulses of multiple bubbles, which caused significant inter-bubble acoustic coupling and mud-bubble interaction. The acoustic signature of subsurface bubble migration and concurrent sediment movements, including bubble pinch off, presented additional complexities. Use of passive acoustic derived flux was applied to natural gas seepage in the Mackenzie Delta in the North West Territories, Canada as well as offshore Coal Oil Point (COP), CA. Video data were used to calibrate the COP acoustic observations and showed a strong current impact for non-cohesive sediments. Seepage flux in the delta (cohesive sediments) was calibrated using a custom turbine tent that directly measured flux. Further applications of passive acoustic-derived seep fluxes include monitoring of marine pipelines for leaks, and studying biogenic wetlands ebullition as well as thermogenic and hydrate seepage.

  7. Tidal river dynamics: Implications for deltas

    Science.gov (United States)

    Hoitink, A. J. F.; Jay, D. A.

    2016-03-01

    Tidal rivers are a vital and little studied nexus between physical oceanography and hydrology. It is only in the last few decades that substantial research efforts have been focused on the interactions of river discharge with tidal waves and storm surges into regions beyond the limit of salinity intrusion, a realm that can extend inland hundreds of kilometers. One key phenomenon resulting from this interaction is the emergence of large fortnightly tides, which are forced long waves with amplitudes that may increase beyond the point where astronomical tides have become extinct. These can be larger than the linear tide itself at more landward locations, and they greatly influence tidal river water levels and wetland inundation. Exploration of the spectral redistribution and attenuation of tidal energy in rivers has led to new appreciation of a wide range of consequences for fluvial and coastal sedimentology, delta evolution, wetland conservation, and salinity intrusion under the influence of sea level rise and delta subsidence. Modern research aims at unifying traditional harmonic tidal analysis, nonparametric regression techniques, and the existing understanding of tidal hydrodynamics to better predict and model tidal river dynamics both in single-thread channels and in branching channel networks. In this context, this review summarizes results from field observations and modeling studies set in tidal river environments as diverse as the Amazon in Brazil, the Columbia, Fraser and Saint Lawrence in North America, the Yangtze and Pearl in China, and the Berau and Mahakam in Indonesia. A description of state-of-the-art methods for a comprehensive analysis of water levels, wave propagation, discharges, and inundation extent in tidal rivers is provided. Implications for lowland river deltas are also discussed in terms of sedimentary deposits, channel bifurcation, avulsion, and salinity intrusion, addressing contemporary research challenges.

  8. Two Component Decomposition of Dual Polarimetric HH/VV SAR Data: Case Study for the Tundra Environment of the Mackenzie Delta Region, Canada

    Directory of Open Access Journals (Sweden)

    Tobias Ullmann

    2016-12-01

    Full Text Available This study investigates a two component decomposition technique for HH/VV-polarized PolSAR (Polarimetric Synthetic Aperture Radar data. The approach is a straight forward adaption of the Yamaguchi decomposition and decomposes the data into two scattering contributions: surface and double bounce under the assumption of a negligible vegetation scattering component in Tundra environments. The dependencies between the features of this two and the classical three component Yamaguchi decomposition were investigated for Radarsat-2 (quad and TerraSAR-X (HH/VV data for the Mackenzie Delta Region, Canada. In situ data on land cover were used to derive the scattering characteristics and to analyze the correlation among the PolSAR features. The double bounce and surface scattering features of the two and three component scattering model (derived from pseudo-HH/VV- and quad-polarized data showed similar scattering characteristics and positively correlated-R2 values of 0.60 (double bounce and 0.88 (surface scattering were observed. The presence of volume scattering led to differences between the features and these were minimized for land cover classes of low vegetation height that showed little volume scattering contribution. In terms of separability, the quad-polarized Radarsat-2 data offered the best separation of the examined tundra land cover types and will be best suited for the classification. This is anticipated as it represents the largest feature space of all tested ones. However; the classes “wetland” and “bare ground” showed clear positions in the feature spaces of the C- and X-Band HH/VV-polarized data and an accurate classification of these land cover types is promising. Among the possible dual-polarization modes of Radarsat-2 the HH/VV was found to be the favorable mode for the characterization of the aforementioned tundra land cover classes due to the coherent acquisition and the preserved co-pol. phase. Contrary, HH/HV-polarized and VV

  9. GLOBAL CHARM OF THE CHANGJIANG RIVER DELTA

    Institute of Scientific and Technical Information of China (English)

    CHEN Shu-peng; ZHOU Cheng-hu; CHEN Qiu-xiao

    2003-01-01

    Based on the theory of geo-economy, under the new situation of global economy, information network and China's entry into WTO, also with the holding of APEC (in 2001) and the International Exposition in the near future, the Changjiang (Yangtze) River Delta is striding toward the spectacular international multi-polar situation and becomes one of core regions with high-speed development. Facing the ocean and world all along, leading the progressive tides of the age and scintillating the splendor of the nation, she does advance with time. Through a long period of irrigation projects construction and intensive operation of lands in previous agricultural society, the artificial wetland ecosystem with a positive cycle had ever been formed in this region. At present, environmental pollution and urban expansion resulted from post-industrialization are being rectified. The delta will be the paradigm of industrial and agricultural modernization along the sustainable development road. With the rapid development of urbanization,she has been one of the regions with the highest density population and high urbanization level. Taking the Changjiang River estuary and the Hangzhou Bay as two parts, she is continuously strengthening and adjusting her interiorstructure, expanding mothball space and constructing the oriental modern "logistics center" to link the whole world. The butterfly-style urban system of the Changjiang River Delta is flying, probably engendering earthshaking "butterfly effect".

  10. Morphodynamics of a cyclic prograding delta: the Red River, Vietnam

    NARCIS (Netherlands)

    Maren, D.S. van

    2004-01-01

    River deltas are inhabited by over 60% of the world population, and are, consequently, of paramount agricultural and economical importance. They constitute unique wetland envi ronments which gives river deltas ecological importance as well. Additionally, many deltas contain large accumulations of oi

  11. Spatial variability of particle-attached and free-living bacterial diversity in surface waters from the Mackenzie River to the Beaufort Sea (Canadian Arctic)

    Science.gov (United States)

    Ortega-Retuerta, E.; Joux, F.; Jeffrey, W. H.; Ghiglione, J. F.

    2013-04-01

    We explored the patterns of total and active bacterial community structure in a gradient covering surface waters from the Mackenzie River to the coastal Beaufort Sea in the Canadian Arctic Ocean, with a particular focus on free-living (FL) vs. particle-attached (PA) communities. Capillary electrophoresis-single-strand conformation polymorphism (CE-SSCP) showed significant differences when comparing river, coast and open sea bacterial community structures. In contrast to the river and coastal waters, total (16S rDNA-based) and active (16S rRNA-based) communities in the open sea samples were not significantly different, suggesting that most present bacterial groups were equally active in this area. Additionally, we observed significant differences between PA and FL bacterial community structure in the open sea, but similar structure in the two fractions for coastal and river samples. Direct multivariate statistical analyses showed that total community structure was mainly driven by salinity (a proxy of dissolved organic carbon and chromophoric dissolved organic matter), suspended particles, amino acids and chlorophyll a. Pyrosequencing of 16S rRNA genes from selected samples confirmed significant differences between river, coastal and sea samples. The PA fraction was only different (15.7% similarity) from the FL one in the open sea sample. Furthermore, PA samples generally showed higher diversity (Shannon, Simpson and Chao indices) than FL samples. At the class level, Opitutae was most abundant in the PA fraction of the sea sample, followed by Flavobacteria and Gammaproteobacteria, while the FL sea sample was dominated by Alphaproteobacteria. Finally, for the coast and river samples and both PA and FL fractions, Betaproteobacteria, Alphaproteobacteria and Actinobacteria were dominant. These results highlight the coexistence of particle specialists and generalists and the role of particle quality in structuring bacterial communities in the area. These results may also

  12. Downstream hydraulic geometry of a tidally influenced river delta

    NARCIS (Netherlands)

    Sassi, M.G.; Hoitink, A.J.F.; Brye, de B.; Deleersnijder, E.

    2012-01-01

    Channel geometry in tidally influenced river deltas can show a mixed scaling behavior between that of river and tidal channel networks, as the channel forming discharge is both of river and tidal origin. We present a method of analysis to quantify the tidal signature on delta morphology, by extendin

  13. Hydrology and morphology of two river mouth regions (temperate Vistula Delta and subtropical Red River Delta

    Directory of Open Access Journals (Sweden)

    Zbigniew Pruszak

    2005-09-01

    Full Text Available The paper presents a comparative analysis of two different river mouths from two different geographical zones (subtropical and temperate climatic regions. One is the multi-branch and multi-spit mouth of the Red River on the Gulf of Tonkin (Vietnam, the other is the smaller delta of the river Vistula on a bay of the Baltic Sea (Poland. The analysis focuses on the similarities and differences in the hydrodynamics between these estuaries and the adjacent coastal zones, the features of sediment transport, and the long-term morphodynamics of the river outlets. Salinity and water level are also discussed, the latter also in the context of the anticipated global effect of accelerated sea level rise. The analysis shows that the climatic and environmental conditions associated with geographical zones give rise to fundamental differences in the generation and dynamic evolution of the river mouths.

  14. Response to Mackenzie

    Science.gov (United States)

    Peers, Chris

    2014-01-01

    Chris Peers begins his response to Jim Mackenzie's article, "Peers on Socrates and Plato" by asking "What is the 'masculine imaginary?'" Peers defines the term "imaginary" as it is applied in his article, "Freud, Plato and Irigaray: A Morpho-Logic of Teaching and Learning" (2012) and draws…

  15. Response to Mackenzie

    Science.gov (United States)

    Peers, Chris

    2014-01-01

    Chris Peers begins his response to Jim Mackenzie's article, "Peers on Socrates and Plato" by asking "What is the 'masculine imaginary?'" Peers defines the term "imaginary" as it is applied in his article, "Freud, Plato and Irigaray: A Morpho-Logic of Teaching and Learning" (2012) and draws…

  16. Water pollution remote sensing for Pearl River Delta

    Science.gov (United States)

    Deng, Ruru; Xiong, Shouping; Qin, Yan

    2008-10-01

    Water pollution on the Delta of Pearl River is increasingly serious and to command the fact of pollution is the key of the control. A remote sensing model for water pollution base on single scattering is deduced in this paper. To avoid the effect by turbidity of water, by analysis the characteristics of the energy composition of multiple scattering, a factor of second scattering is deduced to build a double scattering model, and the practical arithmetic for the calculation of the model is put forwarded and then used to the pollution remote sensing over the Pearl River Delta. The precision of the result is validated by the synchronous measured data on water surface. The result of remote sensing showed that all of the North River, East River and West River are polluted in Pearl River Delta, and the most serious pollution is take place around Guang Zhou City and Dong Guan City.

  17. EAARL Coastal Topography--Pearl River Delta 2008: First Surface

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A first surface elevation map (also known as a Digital Elevation Model, or DEM) of the Pearl River Delta in Louisiana and Mississippi was produced from remotely...

  18. EAARL Coastal Topography--Pearl River Delta 2008: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the Pearl River Delta in Louisiana and Mississippi was produced from remotely sensed,...

  19. EAARL Coastal Topography--Pearl River Delta 2008: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the Pearl River Delta in Louisiana and Mississippi was produced from remotely sensed,...

  20. Topography data from the Elwha River delta, Washington, September 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of the data release presents topography data from the Elwha River delta collected in September 2014. Topography data were collected on foot with global...

  1. Water Quality Assessment of River Areba, Niger Delta, Nigeria ...

    African Journals Online (AJOL)

    Water Quality Assessment of River Areba, Niger Delta, Nigeria Using Physical ... phosphate (0.78mg/l) were above World Health Organization limits for drinking water. Seasonally, water temperatures, total dissolved solids, biological oxygen ...

  2. Hypertension in a Rural Community in Rivers State, Niger Delta ...

    African Journals Online (AJOL)

    Hypertension in a Rural Community in Rivers State, Niger Delta Region of Nigeria: ... (SSA), is now a serious endemic threat and an important public health issue. ... Medical history such as prior knowledge of blood pressure status and family ...

  3. Birds and mammals of the Copper River Delta

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The objectives of this report are: (1) to describe the habitats available for birds and mammals on the Copper River Delta (2) to present an annotated list of birds...

  4. EAARL Coastal Topography--Pearl River Delta 2008: First Surface

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A first surface elevation map (also known as a Digital Elevation Model, or DEM) of the Pearl River Delta in Louisiana and Mississippi was produced from remotely...

  5. A global analysis of human habitation on river deltas

    Science.gov (United States)

    Edmonds, Douglas; Caldwell, Rebecca; Baumgardner, Sarah; Paola, Chris; Roy, Samapriya; Nelson, Amelia; Nienhuis, Jaap

    2017-04-01

    River deltas are ideal sites for human habitation because of their fertile floodplains, easy access to the ocean, and abundant land. But anthropogenic and natural processes are causing deltas to sink, which increases the probability of coastal flooding and human exposure to risk. The full extent of the risk posed to humans is unclear because the number of people living on river deltas is unknown. Towards this end we mapped the locations and areas of all deltas in the world (n= 1813). Using Google Earth we identified all river mouths (≥ 50 m wide) on marine coastlines that are also connected to an upstream catchment. Rivers that split into two or more active or relict distributary channels, end in a depositional protrusion from the shoreline, or do both, are defined as deltas. The depositional protrusion and distributary channel network define the geomorphic area of each delta. We mark the position of the delta apex at the first bifurcation, or for a single channel delta at the intersection of the regional shoreline and the main channel. We mark three lateral extents, one on either side of the main channel at the maximum displacement of the depositional protrusion or the distributary network, and one on the most basinward position of the delta. We define delta area as the convex hull around these extent points and the delta apex. For each delta area polygon we extract elevation from the Shuttle Radar Topography Mission dataset and population count in years 2000, 2005, 2010, 2015, and 2020 from Gridded Population of the World, version 4. In total, deltas cover 0.56% of the total area of the world yet contain 4.1% of the world's population. The population on deltas has grown from 237 million in 2000 to projected values of 322 million in 2020. Deltaic population is growing at 1.59% per year, which outpaces the world growth rate of 1.11%. Additionally, population density is increasing with time from 322 people per km2 in year 2000 to projected values of 422 people per

  6. Comparative Study of Flood Risk Management and Land Use in the Deltas of Rhine River, Yellow River and Mississippi River

    NARCIS (Netherlands)

    Huang B; Guangzhou, M.

    2007-01-01

    The Rhine River in the Netherlands, the Yellow River in China and the Mississippi River in the U.S. are three great rivers in the world. Each of them is performing a significant role in the country. The delta area for each river, in particular, is served as the centre in importance and commonly the

  7. Comparative Study of Flood Risk Management and Land Use in the Deltas of Rhine River, Yellow River and Mississippi River

    NARCIS (Netherlands)

    Huang B; Guangzhou, M.

    2007-01-01

    The Rhine River in the Netherlands, the Yellow River in China and the Mississippi River in the U.S. are three great rivers in the world. Each of them is performing a significant role in the country. The delta area for each river, in particular, is served as the centre in importance and commonly the

  8. Interactions of polychlorinated biphenyls and organochlorine pesticides with sedimentary organic matter of retrogressive thaw slump-affected lakes in the tundra uplands adjacent to the Mackenzie Delta, NT, Canada

    Science.gov (United States)

    Eickmeyer, David C.; Kimpe, Linda E.; Kokelj, Steve V.; Pisaric, Michael F. J.; Smol, John P.; Sanei, Hamed; Thienpont, Joshua R.; Blais, Jules M.

    2016-02-01

    Using a comparative spatial analysis of sediment cores from eight lakes in tundra uplands adjacent to the Mackenzie Delta, NT, we examined how the presence of retrogressive thaw slumps on lake shores affected persistent organic pollutant (POPs, including polychlorinated biphenyls and organochlorine pesticides) accumulation in lake sediments. Sediments of slump-affected lakes contained higher total organic carbon (TOC)-normalized POP concentrations than nearby reference lakes that were unaffected by thaw slumps. Mean focus-corrected inorganic sedimentation rates were positively related to TOC-normalized contaminant concentrations, explaining 58-94% of the variation in POP concentrations in sediment, suggesting that reduced organic carbon in slump-affected lake water results in higher concentrations of POPs on sedimentary organic matter. This explanation was corroborated by an inverse relationship between sedimentary POP concentrations and TOC content of the lake water. Inferred chlorophyll a, S2, and S3 carbon fluxes to sediment were not significantly correlated to POP fluxes. Higher POP concentrations observed in sediment of slump-affected lakes are best explained by simple solvent switching processes of hydrophobic organic contaminants onto a smaller pool of available organic carbon when compared to neighboring lakes unaffected by thaw slump development.

  9. Holocene delta plain development in the Song Hong (Red River) delta, Vietnam

    Science.gov (United States)

    Funabiki, Ayako; Haruyama, Shigeko; Quy, Nguyen Van; Hai, Pham Van; Thai, Dinh Hung

    2007-05-01

    Holocene delta plain development was investigated based on three sediment cores analyzed in detail from the Song Hong (Red River) delta plain in Vietnam. Two cores (DA and PD) from the western delta plain showed both the landward limit of the transgressive estuarine system in the valley incised during the last glacial maximum and floodplain evolution since the middle Holocene. On the other hand, a core (TL) from the eastern delta plain revealed a Pleistocene terrace buried under the deltaic sediments and a slow accumulation rate compared with that in the west. At 8 cal ky BP, the shoreline migrated very close to the present Hanoi city area, and the sedimentary environment changed to tidal flat or salt marsh. Hanoi city marks the northern limit of shoreline transgression. The mangrove swamp expanded from 8 to 5 cal ky BP to the landward limit of the delta plain. Subsequently, the shoreline migrated seaward as a result of delta progradation and sea-level lowering. From 5 cal ky BP, the emerged area evolved into a floodplain and natural levees formed along the abandoned river channels on the western delta plain, but at 2 cal ky, archeological sites indicate that the Holocene terrace in the eastern delta plain was still inundated.

  10. Calculating Lake Morphology in the Colville River Delta, Alaska

    Science.gov (United States)

    McGraw, M.; Walker, H. J.

    2013-12-01

    The morphology and surface area of a lake can be determined using simple mathematical formulas. These formulas can be plugged into a Geographic Information System (GIS) and used to calculate the circularity, smoothness, compactness and orientation of a lake or pond in remotely sensed imagery. The calculated output can then be used to differentiate circular lakes from elongated lakes, lakes with smooth shorelines from those with complex shorelines, and lake orientation; such information can then be used to classify and quantify different types of lakes in complex environments such as river deltas. The Colville River delta is located on the North Slope of Arctic Alaska. Previous studies have classified the delta's 230,000+ lakes into five types: 1. thermokarst (thaw) lakes, 2. oriented lakes, 3. perched lakes, 4 channel lakes and 5. ice-wedge polygon ponds. This study uses 2004 aerial photography and 2011 satellite imagery to quantify the different types of lake in the delta.

  11. Morphology of river deltas on Titan and Earth

    Science.gov (United States)

    Witek, Piotr; Czechowski, Leszek

    2016-07-01

    The Cassini-Huygens mission is entering its final phase. The landing of Huygens on Titan and flybys performed by the Cassini probe during the last ten years revolutionized our knowledge about that moon, revealing a complex fluvio-lacustrine environment. Despite significant differences in composition, temperature and gravity, the processes of sediment transport and deposition are similar on Earth and Titan. We performed numerical simulations of development of river deltas in Titanian and terrestrial conditions, under various discharges and with different dominant grain sizes. We found that evolution of deltaic deposits is more rapid on Titan due to higher efficiency of transport, but the flat, lobate river deltas may form in narrower range of parameters than on Earth. Our results help in understanding the evolution of sedimentary deposits and may partially explain the paucity of river deltas in Titan's lakes.

  12. Sandy River Delta Habitat Restoration Project, Annual Report 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Virginia; Dobson, Robin L.

    2002-11-01

    The Sandy River Delta is located at the confluence of the Sandy and Columbia Rivers, just east of Troutdale, Oregon. It comprises about 1,400 land acres north of Interstate 84, managed by the USDA Forest Service, and associated river banks managed by the Oregon Division of State Lands. Three islands, Gary, Flag and Catham, managed by Metro Greenspaces and the State of Oregon lie to the east, the Columbia River lies to the north and east, and the urbanized Portland metropolitan area lies to the west across the Sandy River. Sandy River Delta was historically a wooded, riparian wetland with components of ponds, sloughs, bottomland woodland, oak woodland, prairie, and low and high elevation floodplain. It has been greatly altered by past agricultural practices and the Columbia River hydropower system. Restoration of historic landscape components is a primary goal for this land. The Forest Service is currently focusing on restoration of riparian forest and wetlands. Restoration of open upland areas (meadow/prairie) would follow substantial completion of the riparian and wetland restoration. The Sandy River Delta is a former pasture infested with reed canary grass, blackberry and thistle. The limited over story is native riparian species such as cottonwood and ash. The shrub and herbaceous layers are almost entirely non-native, invasive species. Native species have a difficult time naturally regenerating in the thick, competing reed canary grass, Himalayan blackberry and thistle. A system of drainage ditches installed by past owners drains water from historic wetlands. The original channel of the Sandy River was diked in the 1930's, and the river diverted into the ''Little Sandy River''. The original Sandy River channel has subsequently filled in and largely become a slough. The FS acquired approximately 1,400 acres Sandy River Delta (SRD) in 1991 from Reynolds Aluminum (via the Trust for Public Lands). The Delta had been grazed for many years

  13. Sediment transportation and bed morphology reshaping in Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The Yellow River Delta supports the ecological function as a typical estuarine foreshore wetland. The wetland area is changing greatly every year because of sediment deposition and erosion, which influences the wetland function tremendously. Application of environmental fluid dynamics code (EFDC) to the Yellow River Delta is on the basis of the mobile bed dynamic model and wetting-drying process. Careful calibration is carried out for the numerical model which is set up for the Yellow River Delta, the sediment transport process of the model is compatible to the Yellow River situation. The simulated bed elevation by considering the sediment deposition in the Mouth is particularly focused on, the numerical results are in agreement with the measured bed morphology within 1992 2000. Simulation in this paper indicates that most of the sediment deposited just out of the Mouth which makes the mouth move forward into the sea 2.5 km per year. This paper presents good results in simulation of varying sediment deposition and provides further methods to predict the future morphology and area of the Yellow River Delta.

  14. FDI and the technological spillover effects: a comparative analysis on the Yangtze River Delta and the Pearl River Delta

    Institute of Scientific and Technical Information of China (English)

    CHEN Xin; ZHENG Yun

    2006-01-01

    This article calculates the technological spillover effects of foreign direct investment (FDI) in the Yangtze River Delta and the Pearl River Delta through Panel Data, and analyzes the influence on the technological spillover effects of the following factors in these two different areas: human capital, the opening up, R&D and the source of FDI. It makes the conclusion that FDI in different areas has different technological spillover effects and the local governments should make different policies accordingly so as to gain more obvious technology spillover effects.

  15. Is there a self-organization principle of river deltas?

    Science.gov (United States)

    Tejedor, Alejandro; Longjas, Anthony; Foufoula-Georgiou, Efi

    2017-04-01

    River deltas are known to possess a complex topological and flux-partitioning structure which has recently been quantified using spectral graph theory [Tejedor et al., 2015a,b]. By analysis of real and simulated deltas it has also been shown that there is promise in formalizing relationships between this topo-dynamic delta structure and the underlying delta forming processes [e.g., Tejedor et al., 2016]. The question we pose here is whether there exists a first order organizational principle behind the self-organization of river deltas and whether this principle can be unraveled from the co-evolving topo-dynamic structure encoded in the delta planform. To answer this question, we introduce a new metric, the nonlocal Entropy Rate (nER) that captures the information content of a delta network in terms of the degree of uncertainty in delivering fluxes from any point of the network to the shoreline. We hypothesize that if the "guiding principle" of undisturbed deltas is to efficiently and robustly build land by increasing the diversity of their flux pathways over the delta plane, then they would exhibit maximum nonlocal Entropy Rate at states at which geometry and flux dynamics are at equilibrium. At the same time, their nER would be non-optimal at transient states, such as before and after major avulsions during which topology and dynamics adjust to each other to reach a new equilibrium state. We will present our results for field and simulated deltas, which confirm this hypothesis and open up new ways of thinking about self-organization, complexity and robustness in river deltas. One particular connection of interest might have important implications since entropy rate and resilience are related by the fluctuation theorem [Demetrius and Manke, 2005], and therefore our results suggest that deltas might in fact self-organize to maximize their resilience to structural and dynamic perturbations. References: Tejedor, A., A. Longjas, I. Zaliapin, and E. Foufoula

  16. Large infrequently operated river diversions for Mississippi delta restoration

    Science.gov (United States)

    Day, John W.; Lane, Robert R.; D'Elia, Christopher F.; Wiegman, Adrian R. H.; Rutherford, Jeffrey S.; Shaffer, Gary P.; Brantley, Christopher G.; Kemp, G. Paul

    2016-12-01

    Currently the Mississippi delta stands as a highly degraded and threatened coastal ecosystem having lost about 25% of coastal wetlands during the 20th century. To address this problem, a 50 billion, 50-year restoration program is underway. A central component of this program is reintroduction of river water back into the deltaic plain to mimic natural functioning of the delta. However, opposition to diversions has developed based on a number of perceived threats. These include over-freshening of coastal estuaries, displacement of fisheries, perceived water quality problems, and assertions that nutrients in river water leads to wetland deterioration. In addition, growing climate impacts and increasing scarcity and cost of energy will make coastal restoration more challenging and limit restoration options. We address these issues in the context of an analysis of natural and artificial diversions, crevasse splays, and small sub-delta lobes. We suggest that episodic large diversions and crevasses (>5000 m3 s-1) can build land quickly while having transient impacts on the estuarine system. Small diversions (water level stress. We use land building rates for different sized diversions and impacts of large periodic inputs of river water to coastal systems in the Mississippi delta to conclude that high discharge diversions operated episodically will lead to rapid coastal restoration and alleviate concerns about diversions. Single diversion events have deposited sediments up to 40 cm in depth over areas up to 130-180 km2. This approach should have broad applicability to deltas globally.

  17. Morphological change in the Pearl River Delta, China

    NARCIS (Netherlands)

    Zhang, W.; Xu, Y.; Hoitink, A.J.F.; Sassi, M.G.; Zheng, J.; Chen, X.; Zhang, C.

    2015-01-01

    Morphological changes in the Pearl River Delta (PRD) have been investigated using bathymetric charts, underwater Digital Elevation Models, remote sensing data and Geographic Information Systems. Water depths were extracted from digitized charts to explore the accretion–erosion characteristics of thr

  18. Seismic stability of the Duwamish River Delta, Seattle, Washington

    Science.gov (United States)

    Kayen, Robert E.; Barnhardt, Walter A.

    2007-01-01

    The delta front of the Duwamish River valley near Elliott Bay and Harbor Island is founded on young Holocene deposits shaped by sea-level rise, episodic volcanism, and seismicity. These river-mouth deposits are highly susceptible to seismic soil liquefaction and are potentially prone to submarine landsliding and disintegrative flow failure. A highly developed commercial-industrial corridor, extending from the City of Kent to the Elliott Bay/Harbor Island marine terminal facilities, is founded on the young Holocene deposits of the Duwamish River valley. The deposits of this Holocene delta have been shaped not only by relative sea-level rise but also by episodic volcanism and seismicity. Ground-penetrating radar (GPR), cores, in situ testing, and outcrops are being used to examine the delta stratigraphy and to infer how these deposits will respond to future volcanic eruptions and earthquakes in the region. A geotechnical investigation of these river-mouth deposits indicates high initial liquefaction susceptibility during earthquakes, and possibly the potential for unlimited-strain disintegrative flow failure of the delta front.

  19. 2009-2010 USACE Vicksburg District Lidar: Mississippi River Delta

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — LiDAR collected at 1.0 points per square meter (1.0m GSD) for the entire portion of the Mississippi River Delta in the Vicksburg District. This area was flown during...

  20. The Government Role in Pan-Pearl River Delta Development

    Institute of Scientific and Technical Information of China (English)

    YiFan; LuRucai

    2004-01-01

    THE Pan-Pearl River Delta (PPRD) Regional Cooperation development strategy has received the central government and relevant State Council departments' immediate attention. As regional cooperation operates under a market system, the governmental role is service-oriented, while enterprises have more decision making power.

  1. Balance of heavy metals in the Volga River delta

    Science.gov (United States)

    Kur'yakova, A. N.

    2011-08-01

    The results of many years of geochemical research of aquatic landscapes are presented. Data on the average annual and seasonal concentrations of heavy metals in water and suspended sediments are given. Factors of migration and accumulation of elements in aquatic landscapes are discussed. Masses of heavy metals annually incoming and accumulated in the Volga River delta were calculated.

  2. Pen Branch Delta and Savannah River Swamp Hydraulic Model

    Energy Technology Data Exchange (ETDEWEB)

    Chen, K.F.

    1999-05-13

    The proposed Savannah River Site (SRS) Wetlands Restoration Project area is located in Barnwell County, South Carolina on the southwestern boundary of the SRS Reservation. The swamp covers about 40.5 km2 and is bounded to the west and south by the Savannah River and to the north and east by low bluffs at the edge of the Savannah River floodplain. Water levels within the swamp are determined by stage along the Savannah River, local drainage, groundwater seepage, and inflows from four tributaries, Beaver Dam Creek, Fourmile Branch, Pen Branch, and Steel Creek. Historic discharges of heated process water into these tributaries scoured the streambed, created deltas in the adjacent wetland, and killed native vegetation in the vicinity of the delta deposits. Future releases from these tributaries will be substantially smaller and closer to ambient temperatures. One component of the proposed restoration project will be to reestablish indigenous wetland vegetation on the Pen Branch delta that covers about 1.0 km2. Long-term predictions of water levels within the swamp are required to determine the characteristics of suitable plants. The objective of the study was to predict water levels at various locations within the proposed SRS Wetlands Restoration Project area for a range of Savannah River flows and regulated releases from Pen Branch. TABS-MD, a United States Army Corps of Engineer developed two-dimensional finite element open channel hydraulic computer code, was used to model the SRS swamp area for various flow conditions.

  3. Urban growth and environmental impacts in Jing-Jin-Ji, the Yangtze, River Delta and the Pearl River Delta

    Science.gov (United States)

    Haas, Jan; Ban, Yifang

    2014-08-01

    This study investigates land cover changes, magnitude and speed of urbanization and evaluates possible impacts on the environment by the concepts of landscape metrics and ecosystem services in China's three largest and most important urban agglomerations: Jing-Jin-Ji, the Yangtze River Delta and the Pearl River Delta. Based on the classifications of six Landsat TM and HJ-1A/B remotely sensed space-borne optical satellite image mosaics with a superior random forest decision tree ensemble classifier, a total increase in urban land of about 28,000 km2 could be detected alongside a simultaneous decrease in natural land cover classes and cropland. Two urbanization indices describing both speed and magnitude of urbanization were derived and ecosystem services were calculated with a valuation scheme adapted to the Chinese market based on the classification results from 1990 and 2010 for the predominant land cover classes affected by urbanization: forest, cropland, wetlands, water and aquaculture. The speed and relative urban growth in Jing-Jin-Ji was highest, followed by the Yangtze River Delta and Pearl River Delta, resulting in a continuously fragmented landscape and substantial decreases in ecosystem service values of approximately 18.5 billion CNY with coastal wetlands and agriculture being the largest contributors. The results indicate both similarities and differences in urban-regional development trends implicating adverse effects on the natural and rural landscape, not only in the rural-urban fringe, but also in the cities' important hinterlands as a result of rapid urbanization in China.

  4. [Evolution process and related driving mechanisms of Yellow River Delta since the diversion of Yellow River].

    Science.gov (United States)

    Han, Guang-Xuan; Li, Yun-Zhao; Yu, Jun-Bao; Xu, Jing-Wei; Wang, Guang-Mei; Zhang, Zhi-Dong; Mao, Pei-Li; Liu, Yu-Hong

    2011-02-01

    Based on the 23 sheets of remote sensing images from 1976 to 2009, in combining with the water and sediment data from Lijin station and the annual precipitation data of Yellow River Basin from 1976 to 2008, this paper quantitatively analyzed the features of water and sediment discharge from Yellow River, and the evolution process of Yellow River Delta and related driving mechanisms. In 1976-2008, the annual runoff and the annual sediment discharge into sea changed largely and frequently, but overall, presented a decreasing trend. Since the course of the Yellow River changed its direction to Qingshui channel in 1976, the Delta coastline and area were generally in a silting-up state. The evolution process of the Delta could be approximately divided into three stages, i.e., 1976-1985, 1986-1995, and 1996-2009, and the increasing rate of the Delta decreased with the stages. The coastline and area of the Delta were significantly exponentially correlated to the sediment accumulated at Lijin station, and the inter-annual variation of the precipitation of the Yellow River Basin had a strong correlation with that of the sediment at Lijin station, suggesting that the annual variation of the precipitation in Yellow River Basin was the main factor affecting the runoff and sediment discharge into sea.

  5. Delta Morphodynamics from River Sediment Input: Dam Removal, Elwha River, Washington, USA.

    Science.gov (United States)

    Warrick, J. A.; Gelfenbaum, G. R.; Stevens, A. W.; Miller, I. M.; Kaminsky, G. M.; Ritchie, A.

    2015-12-01

    Sediment supply plays an important role in river delta morphodynamics and sustainability, and it is important to evaluate how deltas respond to the restoration or enhancement of sediment supplies. Here we report on the morphodynamic responses of the Elwha River delta to large increases in river sediment loads from the removal of two large dams beginning in 2011. The dam removal project exposed ~30 million tonnes of sediment stored within the former reservoirs to natural erosion by the river, and roughly half of this reservoir sediment was eroded during the first four years of the project. Coastal surveys with GPS-based mapping systems, sonar, and aerial photography have revealed that the Elwha River mouth has expanded seaward by ~500 m with the introduction of new supplies of sediment. Approximately 3.5 million cubic meters (or ~5 million tonnes) of sediment were deposited at the river mouth delta between 2011 and 2015. This newly deposited sediment has been shaped by waves and currents into a series of dynamic bars that have greatly expanded the estuarine habitats of the delta.

  6. On river cross-sectional change in the Niger Delta

    Science.gov (United States)

    Abam, T. K. S.; Omuso, W. O.

    2000-08-01

    A network of dominantly distributary river systems dissects the superficial deposits of the Niger Delta comprising alluvial sediments. Changes in river cross-sections are instigated mainly by bank failures, fluctuations in discharge, and bed degradation by fluvial processes. The relative importance of factors causing river cross-sectional change was ranked, based on a deterministic sensitivity technique involving partial differentiation of soil properties, flow characteristics, and geometrical parameters of the river channels. Analysis suggests that steep bank inclination and high flow velocity/discharge are the major causes of cross-sectional change, while interlocking of soil grains is the major erosion-restraining factor. Sensitivity coefficients were used further to generate susceptibility indices, indicating the vulnerability of channel cross-sections to change. Based on this, the risks of channel cross-sectional change were compared at different sites.

  7. Fluvial transport on Titan: formation and evolution of river deltas

    Science.gov (United States)

    Witek, Piotr Przemyslaw; Czechowski, Leszek

    2016-10-01

    The Cassini-Huygens mission provided numerous observations indicating that processes of sediment transport are currently operating on the surface of Titan. We performed numerical simulations of flow and sediment transport on Titan with particular emphasis on formation of sedimentary landforms in Titan's lakes. We compared the morphology and evolution of landforms formed in Titanian and terrestrial conditions, under various discharges and with different dominant grain sizes. The processes are similar in both environments; in some cases we observed bifurcation of the flow and switching of the active distributaries. Such processes may lead to abandonment of some delta lobes, as hypothesized for the delta observed in Ontario Lacus on Titan. The lower gravity of Titan and higher buoyancy of the most plausible kinds of sediment result in higher efficiency of transport and generally faster evolution of the deltaic deposits. Our results suggest also that the flat, lobate river deltas may form in narrower range of parameters than on Earth.

  8. It takes more than water: Restoring the Colorado River Delta

    Science.gov (United States)

    Pitt, Jennifer; Kendy, Eloise; Schlatter, Karen; Hinojosa-Huertaf, Osvel; Flessa, Karl W.; Shafroth, Patrick B.; Ramirez-Hernandez, Jorge; Nagler, Pamela L.; Glenn, Edward P.

    2017-01-01

    Environmental flows have become important tools for restoring rivers and associated riparian ecosystems (Arthington, 2012; Glenn et al., 2017). In March 2014, the United States and Mexico initiated a bold effort in restoration, delivering from Morelos Dam a “pulse flow” of water into the Colorado River in its delta for the purpose of learning about its environmental effects (Flessa et al., 2013; Bark et al., 2016). Specifically, scientists evaluated whether the pulse flow, albeit miniscule compared to historical floods, could provide the ecological functions needed to establish native, flood-dependent vegetation to restore natural habitat along the riparian corridor.

  9. Development of Rural Banks in Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The status quo of new-type rural financial institutions in the Yellow River delta is summarized.It is pointed out that these financial institutions have improved the development of economy concerning agriculture,rural areas and peasants,but due to the shortage of capital,deficit and many other reasons,the outlets is fewer,which can not serve the agriculture,rural areas and peasants well.The necessity of developing rural banks in the Yellow River delta is introduced:firstly,rural banks can serve the agriculture,rural areas and peasants well with flexible system and management methods.Secondly,rural banks can serve and support the vulnerable groups of the three rural issues concerning agriculture,countryside and famers well.Thirdly,rural banks provide strong support for the all around development of rural business concerning the agriculture,rural areas and peasants.Fourthly,rural banks have significant advantages in serving the agriculture,rural areas and peasants.The probability of developing rural banks in the Yellow River delta is analyzed from the three advantages of policy,environment and economy.The challenges faced by the development of rural banks are studied as follows:firstly,the short-term profits are hard to take effect.Secondly,the capital quantity of rural banks is large.Thirdly,the pressure of competition and operation is great.Thus the countermeasures of developing rural banks in the Yellow River delta are put forward:for instance,clarifying the service object in a certain area;using the minority to bring along the majority;reducing the risk of asymmetric information by information technology.

  10. Variance in Dominant Grain Size Across the Mississippi River Delta

    Science.gov (United States)

    Miller, K. L.; Chamberlain, E. L.; Esposito, C. R.; Wagner, R. W.; Mohrig, D. C.

    2016-02-01

    Proposals to restore coastal Louisiana often center on Mississippi River diversion projects wherein water and sediment are routed into wetlands and shallow waters in an effort to build land. Successful design and implementation of diversions will include consideration of behavior and characteristics of sediment, both in the river and in the receiving basin. The Mississippi River sediment load is primarily mud (roughly 75%), with the remainder being very-fine to medium sand or organic detritus. The dominance of muds leads many to suggest that diversions should focus on capturing the mud fraction despite the smaller size and longer settling times required for these particles compared to sand; others believe that sand should be the focus. We present a systemic analysis of the texture of land-building sediment in the Mississippi Delta using borehole data from various depositional environments representing a range of spatial scales, system ages, and fluvial and basin characteristics. We include subdelta-scale data from the incipient Wax Lake Delta and from the distal plain of the abandoned Lafourche subdelta, as well as crevasse-scale data from modern Cubit's Gap and the Attakapas splay, an inland Lafourche crevasse. Comparison of these sites demonstrates a large variance in the volumetric mud to sand ratios across the system. We consider the differences to be emblematic of the various forcings on each lobe as it formed and suggest that the most efficient building block for a diversion is a function of the receiving basin and is not uniform across the entire delta.

  11. Yangtze River Delta and Railway Construction in Sustainable Development

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Yangtze River Delta is the most developed economy and society as well as one of the most densely populated and industrialized regions in China.It is also one of the most dynamic regions with the biggest potential and competitiveness to radiate and generate impetus to the trade development in the middle and western parts of China and in the world.The implementation of sustainable development strategy in the region urgently needs to improve the transportation structure and to solve the problems of constraints and "bottlenecks ".It is necessary to have the global view and insight and catering to the needs of the future to build outbound major railway corridors with a view to enhance the influential and attractive capacities of the Yangtze River Delta region;achieve the goals of construction of intercity railway lines with high standards to form integrated railway systems of the region;and speed up the construction of major hubs in the key cities 'integrated railway system so as to realize easy connection of various modes of transport and improve the railway construction programs with coordinated development of infrastructure.In the meantime,the advantages of different modes will be brought into play to accelerate the harmonious railway development of the Yangtze River Delta region in an all round way.

  12. Groundwater - surface water interactions in the Ayeyarwady river delta, Myanmar

    Science.gov (United States)

    Miyaoka, K.; Haruyama, S.; Kuzuha, Y.; Kay, T.

    2012-12-01

    Groundwater is widely used as a water resource in the Ayeyarwady River delta. But, Groundwater has some chemical problem in part of the area. To use safety groundwater for health, it is important to make clear the actual conditions of physical and chemical characteristics of groundwater in this delta. Besides, Ayeyarwady River delta has remarkable wet and dry season. Surface water - groundwater interaction is also different in each season, and it is concerned that physical and chemical characteristics of groundwater is affected by the flood and high waves through cyclone or monsoon. So, it is necessary to research a good aquifer distribution for sustainable groundwater resource supply. The purposes of this study are evaluate to seasonal change of groundwater - surface water interactions, and to investigate the more safety aquifer to reduce the healthy risk. Water samples are collected at 49 measurement points of river and groundwater, and are analyzed dissolved major ions and oxygen and hydro-stable isotope compositions. There are some groundwater flow systems and these water qualities are different in each depth. These showed that physical and chemical characteristics of groundwater are closely related to climatological, geomorphogical, geological and land use conditions. At the upper Alluvium, groundwater quality changes to lower concentration in wet season, so Ayeyarwady River water is main recharge water at this layer in the wet season. Besides, in the dry season, water quality is high concentration by artificial activities. Shallower groundwater is affected by land surface conditions such as the river water and land use in this layer. At lower Alluvium, Arakan and Pegu mountains are main recharge area of good water quality aquifers. Oxygen18 value showed a little affected by river water infiltration in the wet season, but keep stable good water quality through the both seasons. In the wet season, the same groundwater exists and water quality changes through

  13. Cohesive Sedimentary Processes on River-Dominated Deltas: New Perspectives from the Mississippi River Delta Front, Gulf of Mexico

    Science.gov (United States)

    Bentley, S. J.; Keller, G. P.; Obelcz, J.; Maloney, J. M.; Xu, K.; Georgiou, I. Y.; Miner, M. D.

    2016-12-01

    On river deltas dominated by proximal sediment accumulation (Mississippi, Huang He, others), the delta front region is commonly dominated by rapid accumulation of cohesive fluvial sediments, and mass-wasting processes that remobilize recently deposited sediments. Mass transport is preconditioned in sediments by high water content, biogenic gas production, over steepening, and is commonly triggered by strong wave loading and other processes. This understanding is based on extensive field studies in the 1970's and 80's. Recent studies of the Mississippi River Delta Front are yielding new perspectives on these processes, in a time of anthropogenically reduced sediment loads, rising sea level, and catastrophic deltaic land loss. We have synthesized many industry data sets collected since ca. 1980, and conducted new pilot field and modeling studies of sedimentary and morphodynamic processes. These efforts have yielded several key findings that diverge from historical understanding of this dynamic setting. First, delta distributary mouths have ceased seaward progradation, ending patterns that have been documented since the 18th century. Second, despite reduced sediment supply, offshore mass transport continues, yielding vertical displacements at rates of 1 m/y. This displacement is apparently forced by wave loading from storm events of near-annual return period, rather than major hurricanes that have been the focus of most previous studies. Third, core analysis indicates that this vertical displacement is occurring along failure planes >3 m in the seabed, rather than in more recently deposited sediments closer to the sediment-water interface. These seabed morphodynamics have the potential to destabilize both nearshore navigation infrastructure, and seabed hydrocarbon infrastructure offshore. As well, these findings raise more questions regarding the future seabed evolution offshore of major river deltas, in response to anthropogenic and climatic forcing.

  14. Identifying environmental controls on the shoreline of a natural river delta

    NARCIS (Netherlands)

    Geleynse, N.; Hiatt, M.; Sangireddy, H.; Passalacqua, P.

    River deltas form where sediment-laden water debouches into a basin. The spatial delineation of a delta is nontrivial and yet is fundamental to systematically evaluating fluxes across its surface. Here we study shoreline dynamics of the Wax Lake Delta (WLD), a naturally developing delta, downstream

  15. Identifying environmental controls on the shoreline of a natural river delta

    NARCIS (Netherlands)

    Geleynse, N.; Hiatt, M.; Sangireddy, H.; Passalacqua, P.

    2015-01-01

    River deltas form where sediment-laden water debouches into a basin. The spatial delineation of a delta is nontrivial and yet is fundamental to systematically evaluating fluxes across its surface. Here we study shoreline dynamics of the Wax Lake Delta (WLD), a naturally developing delta, downstream

  16. Against "Ressentiment": Response to Mackenzie

    Science.gov (United States)

    Dahlbeck, Johan

    2016-01-01

    Johan Dahlbeck works as senior lecturer at Malmo University. His research interest is in the philosophy of education, focusing especially on ethics and the pedagogical implications of Spinoza's philosophy. In this article, he responds to Jim Mackenzie's "Dahlbeck and Pure Ontology" (EJ1105980), which was written in reply to his…

  17. Against "Ressentiment": Response to Mackenzie

    Science.gov (United States)

    Dahlbeck, Johan

    2016-01-01

    Johan Dahlbeck works as senior lecturer at Malmo University. His research interest is in the philosophy of education, focusing especially on ethics and the pedagogical implications of Spinoza's philosophy. In this article, he responds to Jim Mackenzie's "Dahlbeck and Pure Ontology" (EJ1105980), which was written in reply to his…

  18. Analysis on Ecological Footprint of the Urban Agglomeration in Pearl River Delta

    Institute of Scientific and Technical Information of China (English)

    ZHONG; Yi; CHENG; Huan; BAI; Zhong-yan; PENG; Xiao-chun

    2012-01-01

    [Objective]The research aimed to calculate and analyze ecological footprint of the urban agglomeration in Pearl River Delta in 2009. [Method]9 cities in Pearl River Delta as research zone, by using calculation model of the ecological footprint, ecological footprint and security of the urban agglomeration in Pearl River Delta were calculated. Current situation and sustainable development condition of the ecological environment in Pearl River Delta were conducted quantitative analysis. [Result] Except construction land and woodland, other 4 kinds of lands were all in ecological deficit states in Pearl River Delta. Especially arable land and fossil fuel land had obvious ecological deficit. [Conclusion]Biological resource consumption level and energy consumption level in Pearl River Delta were higher. We ought to take a variety of measures to reduce ecological deficit, making development manner turn toward sustainable direction.

  19. Changes of Coastal Wetland Ecosystems in the Yellow River Delta and Protection Countermeasures to Them

    OpenAIRE

    Cui, Guangzhou; Zhang, Xuliang; Zhang, Zhaohui; Xu, Zongjun

    2013-01-01

    Coastal wetlands in the Yellow River Delta are typical new wetland ecosystems in warm temperate zone. In recent years, influenced by natural and human factors, these coastal wetlands in the Yellow River Delta have undergone changes of landscape fragmentation, vegetation degradation, pollution, species reduction, and harmful exotic species invasion. These changes have influenced sustainable and healthy development of marine economy of the Yellow River Delta. To protect natural ecological envir...

  20. Morphology of river deltas on Earth and Titan

    Science.gov (United States)

    Witek, Piotr; Czechowski, Leszek

    2016-04-01

    Presently volatile cycles are known to operate on surfaces of two planetary bodies in the Solar System, Earth and Titan. Fluvial erosion, transport and deposition of rocky material modify parts of the surface. Numerous indications of geologically recent sediment transport have been discovered on Titan by the Cassini-Huygens mission. Theoretical calculations suggest greater mobility of Titanian sediments in comparison to terrestrial, due to lower gravity and lower density of typical crustal material. Using numerical model of flow and sediment transport, we compare the development and morphology of deposits forming in lakes in terrestrial and Titanian conditions. We explore the range of possible river discharges, including natural variability, and several dominant grain sizes. We consider several compositions of sediments on Titan, on Earth we model the transport of quartz grains by water. We perform simulations for the same initial geometry of river channel and lake basin, for a given discharge and dominant grain diameter in each environment. Morphology and evolution of the deltaic deposits are compared. We observe that the erosion has dominant role for the smallest grains, and the effect is more pronounced on Titan than on Earth. The largest grains usually form steep-sloped fan-like deltas on both planetary bodies. The processes of formation and development of the sedimentary landforms are generally similar in both environments. Particular types of deposits may however form in different ranges of discharge and grain size, due to differences in environmental parameters. Greater mobility of sediments on Titan result in easier displacement of loose granular material, especially for smallest considered grains. The flat, lobate deltas can form in narrower range of discharges and grain sizes than on Earth. This fact might be partially responsible for scarcity of river deltas on that active moon, where other signs of fluvial processes are widespread.

  1. Employed Farmers in the Pearl River Delta and Related Issues

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    As a special weak group in agricultural floating population,employed farmers make special historic contribution to socio-economic development of the Pearl River Delta.However,employed farmers are faced with survival difficulties,which lead to a series of social issues.From historical origin,current situations and social issues,we put forward countermeasures to solve problems of employed farmers:solve the household registration of employed farmers;raise the compensation standard of land expropriation and demolition;cancel the admission threshold;provide reemployment guidance;and establish management funds of employed farmers.

  2. Biogeochemical features of aquatic plants in the Selenga River delta

    Science.gov (United States)

    Shinkareva, Galina; Lychagin, Mikhail

    2014-05-01

    The Selenga River system provides more than a half of the Lake Baikal total inflow. The river collects a significant amount of pollutants (e.g. heavy metals) from the whole basin. These substances are partially deposited within the Selenga delta, and partially are transported further to the lake. A generous amount of aquatic plants grow in the delta area according to its favorable conditions. This vegetation works as a specific biofilter. It accumulates suspended particles and sorbs some heavy metals from the water. The study aimed to reveal the species of macrophytes which could be mostly important for biomonitoring according to their chemical composition. The field campaign took place in the Selenga River delta in July-August of 2011 (high water period) and in June of 2012 (low water period). 14 species of aquatic plants were collected: water starwort Callitriche hermaphroditica, small yellow pond lily Nuphar pumila, pondweeds Potamogeton crispus, P. pectinatus, P. friesii, broadleaf cattail Typha latifolia, hornwort or coontail Ceratophyllum demersum, arrowhead Sagittaria natans, flowering rush (or grass rush) Butomus umbellatus, reed Phragmites australis, parrot's feather Myriophyllum spicatum, the common mare's tail Hippuris vulgaris, Batrachium trichophyllum, canadian waterweed Elodea canadensis. The samples were dried, grinded up and digested in a mixture of HNO3 and H2O2. The chemical composition of the plant material was defined using ICP-MS and ICP-AES methods. Concentrations of Fe, Mn, Cr, Ni, Cu, B, Zn, V, Co, As, Mo, Pb, and U were considered. The study revealed that Potamogeton pectinatus and Myriophyllum spicatum concentrate elements during both high and low water periods. Conversely the Butomus umbellatus and Phragmites australis contain small amount of heavy metals. The reed as true grasses usually accumulates fewer amounts of elements than other macrophytes. To compare biogeochemical specialization of different species we suggest to use

  3. Huang Daopo and the Rise of the Changjiang River Delta

    Institute of Scientific and Technical Information of China (English)

    PengAnyu

    2005-01-01

    The Changjiang River Delta centered on Shanghai was originally not a cotton growing area, and hence had no cotton textile industry to speak of. By the Tang Dynasty, cotton cloth was no longer a rare sight in the area, but cotton was still not grown there. The people still relied on silkworm breeding and mulberry growing for a living, and were known throughout the country for their silk fabrics. It was not until the late Southern Song Dynasty that cotton growing began to appear, as evidenced by the late Song poet Ai Keshu's poem “Ode to Silk Cotton.”

  4. Bathymetry of the Hong and Luoc River Junction, Red River Delta, Vietnam, 2010

    Science.gov (United States)

    Kinzel, Paul J.; Nelson, Jonathan M.; Toan, Duong Duc; Thanh, Mung Dinh; Shimizu, Yasuyuki

    2012-01-01

    The U.S. Geological Survey, in collaboration with the Water Resources University in Hanoi, Vietnam, conducted a bathymetric survey of the junction of the Hong and Luoc Rivers. The survey was done to characterize the channel morphology of this delta distributary network and provide input for hydrodynamic and sediment transport models. The survey was carried out in December 2010 using a boat-mounted multibeam echo sounder integrated with a global positioning system. A bathymetric map of the Hong and Luoc River junction was produced which was referenced to the datum of the Trieu Duong tide gage on the Luoc River.

  5. Impacts of the Indian Rivers Inter-link Project on Sediment Transport to River Deltas

    Science.gov (United States)

    Higgins, S.; Overeem, I.; Syvitski, J. P.

    2015-12-01

    The Indian Rivers Inter-link project is a proposal by the Indian government to link several of India's major rivers via a network of reservoirs and canals. Variations of the IRI have been discussed since 1980, but the current plan has recently received increased support from the Indian government. Construction on three canals has controversially begun. If the Inter-link project moves forward, fourteen canals will divert water from tributaries of the Ganges and Brahmaputra rivers to areas in the west, where fresh water is needed for irrigation. Additional canals would transport Himalayan sediments 500 km south to the Mahanadi delta and more than 1000 km south to the Godavari and Krishna deltas. We investigate the impacts of the proposed diversions on sediment transport to the Mahanadi/Brahmani, Godavari, and Krishna deltas in India and the Ganges-Brahmaputra Delta in Bangladesh. We map the entire river network and the proposed new nodes and connections. Changing watersheds are delineated using the Terrain Analysis Using Digital Elevation Models (TauDEM) Suite. Climate data comes from interpolation between observed precipitation stations located in China, Nepal, India, Bhutan and Bangladesh. Changes in water discharge due to the proposed canals are simulated using HydroTrend, a climate-driven hydrological water balance and transport model that incorporates drainage area, discharge, relief, temperature, basin-average lithology, and anthropogenic influences. Simulated river discharge is validated against observations from gauging stations archived by the Global Runoff Data Center (GRDC). HydroTrend is then used to investigate sediment transport changes that may result from the proposed canals. We also quantify changes in contributing areas for the outlets of nine major Indian rivers, showing that more than 50% of the land in India will contribute a portion of its runoff to a new outlet should the entire canal system be constructed.

  6. Challenges and Approaches in River Delta Planning - report on training workshop

    NARCIS (Netherlands)

    Wosten, J.H.M.; Douven, W.; Long Phi, H.; Fida Abdullah Khan, M.

    2012-01-01

    River delta’s, like the Mekong Delta (Vietnam), Ganges-Brahmaputra Delta (Bangladesh), Irrawady (Myanmar) and Ciliwung Delta (Indonesia) are developing rapidly and characterized by large-scale urbanization and industrialization processes. They are facing serious planning challenges related to issues

  7. Spatio-temporal patterns and predictions of phytoplankton assemblages in a subtropical river delta system

    DEFF Research Database (Denmark)

    2016-01-01

    Spatial and seasonal sampling within a subtropical river delta system, the Pearl River Delta (China), provided data to determine seasonal phytoplankton patterns and develop prediction models. The high nutrient levels and frequent water exchanges resulted in a phytoplankton community with greatest...

  8. Land-ocean interaction in modern delta formation and development: A case study of the Pearl River delta, China

    Institute of Scientific and Technical Information of China (English)

    李春初; 雷亚平; 何为; 戴志军

    2001-01-01

    The distinctive characteristics of the modern Pearl River delta formation and development are divided phases, diversity and imbalance in spatial and temporal. The delta was moving seaward gradually in a long period after the last Holocene glacial stage and the ancient drowned Pearl River estuary was predominated by tide. The delta was expanding quickly since fluvial force was turned to be leading status about 2500 years ago. The sediment grain size was changing longitudinally from coarser to finer. As well as the finer sediment may be reworked and redistributed shoreward by tidal current nearby the river mouth. And the fluvial-dominated delta is developed by the mutual deposition reflected in the vertical direction. According to the spatial difference of land-ocean interaction, the main body of the Pearl River delta which is the fluvial-dominated and protruding seaward is coupled with or concomitant with the estuaries and tide-dominated deltas which are adjoined to both sides of the main part like two wi

  9. PEARL RIVER DELTA OIL PRODUCTS PIPELINE ENTERS SHENZHEN

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ With the strong support of Shenzhen, Huizhou Municipal governments and Shenzhen Petroleum Subsidiary Company, the construction of Shenzhen (Huizhou) section of Pearl River Delta oil products pipeline was started ahead of schedule on Sep.30, 2004,and coordination work for most of Shenzhen section has been completed up to the end of April this year.Presently, the construction of Shenzhen section is carried out smoothly in general, for the pipeline route, 69km for pileline pruging, 60km for pipe laying, 57.7km for welding; for process stations, the removal of Mawan oil storage has been completed by the plan, and the foundation for Dapengwan oil storage tank is under construction.

  10. Water management in the Senegal River Delta: a continuing uncertainty

    Directory of Open Access Journals (Sweden)

    M. Mietton

    2007-11-01

    Full Text Available Water management is the driving force behind the productivity of the ecosystems of the Senegal River Estuary and floodplains. It is dependent on human decision-making, but has been separated from the River's flooding since the building of the Diama Dam. The current objectives of the Office de Mise en Valeur du fleuve Sénégal (OMVS: Senegal River Development Agency are mainly turned towards the development of irrigated agriculture on the former floodplains and since 2002 the production of hydroelectric power at Manantali. In October 2003, a four-metre-wide runoff canal, which quickly widened into a breach several hundred metres across, was dug in the Barbary Spit area to protect the city of Saint-Louis from heavy flooding. The hydraulic quality of the area downstream from the dam has improved to the extent that there is no longer any flooding there, but as the management of the dams concerns only the section of the river between Manantali and Diama, a certain amount of flood risk probably still persists. The intrusion of seawater into the estuary is also threatening ecosystems and fresh water supplies, and abruptly altering agricultural practices such as fruit and vegetable growing in the Gandiolais district. When added to the tentative efforts to coordinate the management of the two dams, with no management objective downstream from Diama, such permanent modifications impose serious constraints on the managers and residents of the lower delta. This paper presents an overview of the constraints and uncertainties at different levels and scales. This wholly human-wrought environment can be considered as a learning experience, where a large number of variables need to be monitored closely and an ongoing process of participatory analysis should be backed up by multidisciplinary research.

  11. Natural and Human Impacts on Recent Development of Asian Large Rivers and Deltas

    Science.gov (United States)

    Liu, P.; Lu, C.

    2014-12-01

    Most recent data analysis indicates sediment loads in most of Asian large rivers (like, Yellow, Yangtze, Pearl, Chao Phraya, Indus, Krishna, Godavari, etc) have decreased up to 80-90% in the past 60 years. Correspondingly, most of Asian large river deltas are facing severe sediment starving; delta shoreline comparisons indicate that some are under strong coastal erosion. For examples, the Yellow River Delta has been retreating since 1990s when its annual sediment load has kept below 300 million tons. The Yangtze River delta kept growing before Three Gorges Dams was operating, and began to be eroded from the year 2003 to 2009, and then prograded locally due to the Deep Water Navigation Project. The Mekong Delta shoreline has also been dynamically changing with the sediment flux variation, eroding from 1989 to 1996 and prograding from 1996 to 2002. More information is available at http://www.meas.ncsu.edu/sealevel

  12. Characteristics of soil salinity in the typical area of Yellow River Delta and its control measures

    Science.gov (United States)

    Zhang, Mingliang; Wang, Haixia; Pang, Xiaoke; Liu, Hui; Wang, Qun

    2017-05-01

    The Yellow River Delta is one of important ecological areas in eastern China, however sustainable development of the Yellow River Delta is seriously restricted because of severe soil salinization. The main sources of soil salinity are chloride, sodium and sulfate ions. The distribution of soil salinity in soil profiles showed that surface accumulation of soil salt was significant in the Yellow River Delta. Some control measures including soil improvement and regulation, reasonable combination of salt-fresh water irrigation in farmland, land cover and effective drainage were put forward for soil salinity control.

  13. Goose Mass and Vegetation Data, Colville River Delta, Alaska, 2012-2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data release contains three tables of information from the Colville River Delta, Alaska, 2012-2014: offtake of Carex subspathacea, standing crop of C....

  14. Digital elevation models (DEMs) of the Elwha River delta, Washington, September 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of the data release presents a digital elevation model (DEM) derived from bathymetry and topography data of the Elwha River delta collected in September...

  15. Digital elevation models (DEMs) of the Elwha River delta, Washington, May 2011

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of the data release presents a digital elevation model (DEM) derived from bathymetry and topography data of the Elwha River delta collected in May 2011....

  16. Surface-sediment grain-size distributions from the Elwha River delta, Washington, July 2015

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, between July and August 2015 (USGS...

  17. Surface-sediment grain-size distributions from the Elwha River delta, Washington, May 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in May 2014 (USGS Field Activity...

  18. Surface-sediment grain-size distributions from the Elwha River delta, Washington, March 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in March 2013 (USGS Field Activity...

  19. Surface-sediment grain-size distributions of the Elwha River delta, Washington, July 2016

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in July 2016 (USGS Field Activity...

  20. Surface-sediment grain-size distributions of the Elwha River delta, Washington, January 2015

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in January 2015 (USGS Field Activity...

  1. Surface-sediment grain-size distributions from the Elwha River delta, Washington, September 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in September 2013 (USGS Field...

  2. Surface-sediment grain-size distributions from the Elwha River delta, Washington, September 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in September 2014 (USGS Field...

  3. Surface-sediment grain-size distributions from the Elwha River delta, Washington, August 2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents sediment grain-size data from samples collected on the Elwha River delta, Washington, in August 2012 (USGS Field Activity...

  4. Northern Manitoba, northern Saskatchewan, and the Saskatchewan River Delta: Waterfowl production survey: 2000

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the Waterfowl Production and Habitat Survey for northern Manitoba, northern Saskatchewan, and the Saskatchewan River Delta during 2000. The...

  5. Digital elevation models (DEMs) of the Elwha River delta, Washington, August 2011

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of the data release presents a digital elevation model (DEM) derived from bathymetry and topography data of the Elwha River delta collected in August 2011....

  6. Development of an aerial breeding pair survey for geese nesting in the Copper River Delta

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The U.S. Fish and Wildlife Service initiated a new aerial survey of breeding dusky Canada geese (Branta canadensis occidentalis) on the Copper River Delta in 1986...

  7. Bird populations and habitat use, Canning River Delta, Alaska: Report to Arctic National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bird populations and use of habitat at the Canning River Delta, Arctic National Wildlife Refuge, was the subject of a study during the summer of 1979 and 1980....

  8. Digital elevation models (DEMs) of the Elwha River delta, Washington, July 2016

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of the data release presents a digital elevation model (DEM) derived from bathymetry and topography data of the Elwha River delta collected in July 2016....

  9. Digital elevation models (DEMs) of the Elwha River delta, Washington, September 2010

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of the data release presents a digital elevation model (DEM) derived from bathymetry and topography data of the Elwha River delta collected in September...

  10. Digital elevation models (DEMs) of the Elwha River delta, Washington, August 2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of the data release presents a digital elevation model (DEM) derived from bathymetry and topography data of the Elwha River delta collected in August 2012....

  11. Nearshore bathymetry data from the Elwha River delta, Washington, February 2016, collected from personal watercraft

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of the data release presents bathymetry data from the Elwha River delta collected in February 2016 using two personal watercraft (PWCs). The PWCs were...

  12. Building a competitive Pearl River Delta region: cooperation, coordination, and planning

    OpenAIRE

    2002-01-01

    Papers mainly originated from the Seminar on Building a Competitive Pearl River Delta Region: Cooperation, Coordination and planning held on 8 July 2000 at the Hong Kong Convention and Exhibition Centre

  13. Changes of Coastal Wetland Ecosystems in the Yellow River Delta and Protection Countermeasures to Them

    Institute of Scientific and Technical Information of China (English)

    Guangzhou; CUI; Xuliang; ZHANG; Zhaohui; ZHANG; Zongjun; XU

    2013-01-01

    Coastal wetlands in the Yellow River Delta are typical new wetland ecosystems in warm temperate zone. In recent years, influenced by natural and human factors, these coastal wetlands in the Yellow River Delta have undergone changes of landscape fragmentation, vegetation degradation, pollution, species reduction, and harmful exotic species invasion. These changes have influenced sustainable and healthy development of marine economy of the Yellow River Delta. To protect natural ecological environment of the Yellow River Delta, the authors recommended that it should establish and improve policies, laws and regulations of wetland protection; carry out wetland resource investigation and assessment and monitoring; strengthen comprehensive protection and control of wetland; reduce wetland degradation and promote sustainable use of wetland.

  14. Waterfowl production survey: Northern Saskatchewan, northern Manitoba, Saskatchewan River Delta: July 10-22, 1973

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the Waterfowl Production and Habitat Survey for northern Saskatchewan, northern Manitoba, and the Saskatchewan River Delta during 1973. The...

  15. Northern Manitoba, northern Saskatchewan, and the Saskatchewan River Delta: Waterfowl production survey: 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the Waterfowl Production and Habitat Survey for northern Manitoba, northern Saskatchewan, and the Saskatchewan River Delta during 1993. The...

  16. The status of snow geese in the Sagavanirktok River Delta, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The study of snow geese in the Sagavanirktok River Delta in 1982 was an extension of a program that began in 1980 and continued in 1981. Because the nesting colony...

  17. River salinity on a mega-delta, an unstructured grid model approach.

    Science.gov (United States)

    Bricheno, Lucy; Saiful Islam, Akm; Wolf, Judith

    2014-05-01

    With an average freshwater discharge of around 40,000 m3/s the BGM (Brahmaputra Ganges and Meghna) river system has the third largest discharge worldwide. The BGM river delta is a low-lying fertile area covering over 100,000 km2 mainly in India and Bangladesh. Approximately two-thirds of the Bangladesh people work in agriculture and these local livelihoods depend on freshwater sources directly linked to river salinity. The finite volume coastal ocean model (FVCOM) has been applied to the BGM delta in order to simulate river salinity under present and future climate conditions. Forced by a combination of regional climate model predictions, and a basin-wide river catchment model, the 3D baroclinic delta model can determine river salinity under the current climate, and make predictions for future wet and dry years. The river salinity demonstrates a strong seasonal and tidal cycle, making it important for the model to be able to capture a wide range of timescales. The unstructured mesh approach used in FVCOM is required to properly represent the delta's structure; a complex network of interconnected river channels. The model extends 250 km inland in order to capture the full extent of the tidal influence and grid resolutions of 10s of metres are required to represent narrow inland river channels. The use of FVCOM to simulate flows so far inland is a novel challenge, which also requires knowledge of the shape and cross-section of the river channels.

  18. Retreat of the State: Marketization of Education in the Pearl River Delta.

    Science.gov (United States)

    Mok, Ka-Ho

    1997-01-01

    Analyzes how a flourishing market economy has affected China's social policy and educational development, focusing on "marketization" and "privatization" in the Pearl River Delta, Guangdong Province. The Delta's expansion of multiple financial sources for education and huge demand for professional and technical education have…

  19. Plant community succession in modern Yellow River Delta, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Data were collected in different successional stages using a simultaneous sampling method and analyzed through quantitative classification method. Three large groups and 12 classes were made to represent the community patterns of three succession stages and 12 succession communities. The succession series of plant community in the study area was as follows:saline bare land→community Suaeda salsa→community Tamarix chinensis→grassland. Succession degree and succession process of 12 succession communities were calculated. Most of these communities were in the lower succession stage, however,community Phragmites communis+Glycine soja and community Imperata cylindrica+G. soja were close to the succession stage of grassland climax. Five species diversity indices were used to study the changes in species richness, species evenness and diversity during succession of community. Heterogeneity index and richness index increased gradually during the community succession process, but species evenness tended to decrease with succession development. The relation between succession and environment was studied by ordination technique, and the results showed that the soil salt content was an important factor to halarch succession of the modern Yellow River Delta. It affected community structure, species composition and succession process.

  20. The sediment-starved Yellow River Delta as remotely controlled by human activities in the river basin

    Science.gov (United States)

    Wang, H.; Bi, N.

    2015-12-01

    Human presented significant disturbances on the natural processes of land-ocean interactions in context of global change. Here we illustrate how the signals of human activities in the river basin have been transferred to the coastal ocean along the hydrological pathway and remotely controlled the Yellow River Delta. Dam-orientated water and sediment regulation scheme (WSRS) has resulted in effective erosion of the lower channel and mitigation of siltation within the reservoirs. However, significant impacts have been identified on the delta morphology and coastal ecosystem ten years after the WSRS, which was unexpected at the beginning of engineering efforts. The coarser sediment derived from the channel erosion during the first phase of WSRS was directly contributed to the rapid accretion of present river mouth, whereas the delta was starved and declined due to insufficient sediment supply and regime shift of sediment transport. The fine-grained sediment exported from the Xiaolangdi Reservoir during the second phase of WSRS seemed to be a critical carrier for the nutrients and pollutants. The human-altered hydrological cycle, enhanced delivery of nutrient and pollutants and the changing estuarine environment present unpredictable impacts on both terrestrial and aquatic ecosystem in the delta region. These confirm that humans are modifying the river-coast system in ways that go well beyond climate change, and an integrated management of the river-coast continuum is crucially important for the sustainability of the river-delta system.

  1. Progradation of the Changjiang River delta since the mid-Holocene

    Institute of Scientific and Technical Information of China (English)

    HoriKazuaki; SaitoYoshiki; 赵泉鸿; 汪品先; 李从先

    2001-01-01

    Subaqueous deltaic deposits with approximately 30 radiocarbon ages show that the Changjiang River delta was strongly affected by tides and that the delta progradation rate after 2 kaBP was almost double the rate before 2 kaBP. This change in the progradation rate correlates well with the active extension of the subaerial delta plain shown by previous work. Widespread human activities, such as farming, deforestation, and dike construction, probably resulted in an increase in sediment discharge to the river-mouth area.

  2. Deltaic Morphology and Sedimentology, with Special Reference to the Indus River Delta.

    Science.gov (United States)

    1985-01-01

    Shatt-al-Arab, and Chao submarine canyon restricts subaqueous delta Phraya (Fig. 10). The role of tides in the Indus development by funneling sediment...D -R I B S 1 9 8 D E L T I C M O R P H O L O G Y A N D S E D I E N T O L O G Y N I T H S P E C I LREFERENCE TO THE INDUS RIVER DELTA(U) LOUISIANA...424 DELTAIC MORPHOLOGY AND SEDIMENTOLOGY WITH SPECIAL REFERENCE TO THE INDUS RIVER DELTA J. T. Wells and J. M. Coleman 1985 Marine Geology

  3. Network topology, Transport dynamics, and Vulnerability Analysis in River Deltas: A Graph-Theoretic Approach

    Science.gov (United States)

    Tejedor, A.; Foufoula-Georgiou, E.; Longjas, A.; Zaliapin, I. V.

    2014-12-01

    River deltas are intricate landscapes with complex channel networks that self-organize to deliver water, sediment, and nutrients from the apex to the delta top and eventually to the coastal zone. The natural balance of material and energy fluxes which maintains a stable hydrologic, geomorphologic, and ecological state of a river delta, is often disrupted by external factors causing topological and dynamical changes in the delta structure and function. A formal quantitative framework for studying river delta topology and transport dynamics and their response to change is lacking. Here we present such a framework based on spectral graph theory and demonstrate its value in quantifying the complexity of the delta network topology, computing its steady state fluxes, and identifying upstream (contributing) and downstream (nourishment) areas from any point in the network. We use this framework to construct vulnerability maps that quantify the relative change of sediment and water delivery to the shoreline outlets in response to possible perturbations in hundreds of upstream links. This enables us to evaluate which links (hotspots) and what management scenarios would most influence flux delivery to the outlets, paving the way of systematically examining how local or spatially distributed delta interventions can be studied within a systems approach for delta sustainability.

  4. Community-based restoration of desert wetlands: the case of the Colorado River delta

    Science.gov (United States)

    Osvel Hinojosa-Huerta; Mark Briggs; Yamilett Carrillo-Guerroro; Edward P. Glenn; Miriam Lara-Flores; Martha Roman-Rodriguez

    2005-01-01

    Wetland areas have been drastically reduced through the Pacific Flyway and the Sonoran Desert, with severe consequences for avian populations. In the Colorado River delta, wetlands have been reduced by 80 percent due to water management practices in the Colorado River basin. However, excess flows and agricultural drainage water has restored some areas, providing...

  5. Tidal impact on the division of river discharge and distributary channels in the Mahakam Delta

    NARCIS (Netherlands)

    Sassi, M.G.; Hoitink, A.J.F.; Brye, de B.; Vermeulen, B.; Deleersnijder, E.

    2011-01-01

    Bifurcations in tidally influenced deltas distribute river discharge over downstream channels, asserting a strong control over terrestrial runoff to the coastal ocean. Whereas the mechanics of river bifurcations is well-understood, junctions in tidal channels have received comparatively little atten

  6. Diversidade de peixes do reservatório da UHE Escola Engenharia Mackenzie (Capivara, Rio Paranapanema, bacia do alto rio Paraná, Brasil, e a importância dos grandes tributários na sua manutenção Fish diversity in the UHE Escola Engenharia Mackenzie (Capivara reservoir, Paranapanema River, upper Rio Paraná basin, Brazil, and the importance of large tributaries in its maitenance

    Directory of Open Access Journals (Sweden)

    Ana Cecília Hoffmann

    2005-09-01

    Full Text Available As espécies foram coletadas em quatro trechos ao longo de um gradiente formado pelo reservatório UHE Escola Engenharia Mackenzie (Capivara. A diversidade de espécies foi analisada pela constância, índice de Shannon-Wiener e similaridade da composição entre trechos através do coeficiente de Jaccard. O reservatório tem uma riqueza de peixes composta por 67 espécies incluídas em 5 ordens; 47% das espécies são constantes, 15 % são acessórias e 28% são acidentais. Os maiores índices de diversidade de Shannon-Wiener e similaridade de Jaccard foram obtidos em Cinzas e Tibagi, que são os trechos mais distantes da barragem e que apresentam grandes tributários. Os menores índices foram encontrados em Cruzália e Porecatu, os quais correspondem aos trechos com características, respectivamente, de ambientes lótico e semi-lótico. Este trabalho demonstra a extrema importância da presença dos tributários para a manutenção da diversidade das espécies em um reservatório, em função da preservação das características originais do sistema lótico naqueles trechos e conseqüente redução do impacto do represamento.Fish samples were taken in four stretches along a gradient formed by the UHE Escola Engenharia Mackenzie (Capivara reservoir. The diversity of species was analyzed by the constance, index of Shannon-Wiener and similarity of the composition among stretches through the Jaccard's coefficient. The reservoir presents a richness of fishes composed by 67 species distributed in 5 orders; 47% of the species are constant, 15% are accessory and 28% are accidental. The highest values of Shannon-Wiener diversity and Jaccard's similarity were obtained in Cinzas and Tibagi, wich are the most distant points from the dam and which present large tributaries. The lowest values were found in Cruzália and Porecatu, which respectively correspond to the stretches with lotic and semi-lotic environmental characteristics. This work demonstrates

  7. [Community structure of planktonic rotifers in the Pearl River Delta].

    Science.gov (United States)

    Gao, Yuan; Li, Xin-Hui; Lai, Zi-Ni; Yu, Jing; Wang, Chao; Zeng, Yan-Yi; Liu, Qian-Fu; Yang, Wan-Ling

    2014-07-01

    Four ecological investigations were carried out on planktonic rotifers in Pearl River Delta in 2012. The community structure, including spatial and temporal patterns of species composition, dominant species, biomass and biodiversity, was investigated. The correlation between the community structure of rotifers and the environmental factors was discussed. Moreover, the aggregation structures of rotifers were analyzed. A total of 53 rotifer species were found. Dominant species changed markedly with season and space. Polyarthra trigla had higher dominance. In terms of seasonal changes, the density and biomass were higher in dry season than in wet season, while the biodiversity and evenness indices were vice versa. The biomass and biodiversity of rotifers showed highly significant differences among seasons. In terms of spatial distribution, the average density and the average biomass showed an increase from the southwest to the northeast. The highest density and biomass were recorded in Shiqiao. The biodiversity and evenness indices had an opposite spatial distribution, with the highest values being recorded in Qingqi. The rotifer density was significantly different among the investigated sites, while the biomass and biodiversity were not significantly different. Correlation analysis demonstrated a highly significant positive correlation between rotifer density and biomass, as well as between biodiversity and evenness indices, and a highly negative correlation between biodiversity and biomass. The biodiversity and evenness indices both decreased markedly with the increase of biomass. Principal component analysis indicated that the rotifer density was closely correlated with environment factors, such as water temperature, pH, dissolved oxy- gen, chlorophyll a content, total phosphorus, and total nitrogen, in different seasons. Aggregation analysis based on rotifer density revealed five aggregation structures in the investigated sites, indicating significant differences

  8. The Atchafalaya River Delta. Report 4. Generic Analysis of Delta Development.

    Science.gov (United States)

    1984-01-01

    contemporaneously with delta growth (Donaldson, Martin , and Kanes 1970). The average rate of contour advancement has been ap- proximately 12 m/yr. Assuming the...Donaldson, Martin , ’, and Kanes 1970) shows that the delta has transgressed over 60 m. Average rates of deterioration are reported to be 2.75 m/yr...after 1965 ( Keown , Dardeau, and Causey 1980). Coarse sediment not reaching the delta is precisely the material needed for subaerial land. Third, the

  9. Connectivity in river deltas: Field measurements and development of a conceptual framework

    Science.gov (United States)

    Passalacqua, P.; Hiatt, M. R.

    2014-12-01

    River deltas are dynamic systems composed of a network of channels and interchannel islands that are subject to forces such as river discharge, tides, wind, and anthropogenic activities. The delivery of water, sediment, and nutrients from the channel to the delta floodplain is important for maintaining and evolving delta systems. This delivery depends on the connectivity between channels and delta floodplains. Connectivity is a concept that has been investigated extensively in tributary systems but remains relatively unexplored in delta distributary networks. This may be due to the structure of delta networks, often more complex than the one of tributary networks, and forces such as wind and tides acting on delta systems. In this study, we present a framework for analyzing connectivity in river delta networks and present field evidence of surface water connectivity mechanisms from Wax Lake Delta (WLD) in coastal Louisiana, USA through measurements of water discharge and hydraulic tracer propagation. Calculated discharges from velocity measurements reveal that 46-77% of the flow exits the system via the distributary channels, while the remaining volume is routed to the islands, highlighting the importance of channel-island connectivity and the role of islands in the hydrological network at WLD. Tides and wind also play an important role in the channel-island connectivity by modulating flow into and out of the islands, as well as influencing the hydraulic residence time of the inundated island interiors, which has implication for nutrient cycling. A framework for analyzing connectivity in river deltas is presented, in which we characterize the importance of dynamic island inundation, environmental forces, and network structure.

  10. Morphologic and stratigraphic evolution of muddy ebb-tidal deltas along a subsiding coast: Barataria Bay, Mississippi River delta

    Science.gov (United States)

    FitzGerald, D.M.; Kulp, M.; Penland, S.; Flocks, J.; Kindinger, J.

    2004-01-01

    The Barataria barrier coast formed between two major distributaries of the Mississippi River delta: the Plaquemines deltaic headland to the east and the Lafourche deltaic headland to the west. Rapid relative sea-level rise (1??03 cm year-1) and other erosional processes within Barataria Bay have led to substantial increases in the area of open water (> 775 km2 since 1956) and the attendant bay tidal prism. Historically, the increase in tidal discharge at inlets has produced larger channel cross-sections and prograding ebb-tidal deltas. For example, the ebb delta at Barataria Pass has built seaward > 2??2 km since the 1880s. Shoreline erosion and an increasing bay tidal prism also facilitated the formation of new inlets. Four major lithofacies characterize the Barataria coast ebb-tidal deltas and associated sedimentary environments. These include a proximal delta facies composed of massive to laminated, fine grey-brown to pale yellow sand and a distal delta facies consisting of thinly laminated, grey to pale yellow sand and silty sand with mud layers. The higher energy proximal delta deposits contain a greater percentage of sand (75-100%) compared with the distal delta sediments (60-80%). Associated sedimentary units include a nearshore facies consisting of horizontally laminated, fine to very fine grey sand with mud layers and an offshore facies that is composed of grey to dark grey, laminated sandy silt to silty clay. All facies coarsen upwards except the offshore facies, which fines upwards. An evolutionary model is presented for the stratigraphic development of the ebb-tidal deltas in a regime of increasing tidal energy resulting from coastal land loss and tidal prism growth. Ebb-tidal delta facies prograde over nearshore sediments, which interfinger with offshore facies. The seaward decrease in tidal current velocity of the ebb discharge produces a gradational contact between proximal and distal tidal delta facies. As the tidal discharge increases and the inlet

  11. Spatial variations of river water quality in Pearl River Delta, China

    Institute of Scientific and Technical Information of China (English)

    Xiaoyun FAN; Baoshan CUI; Zhiming ZHANG

    2012-01-01

    In Pearl River Delta (PRD),river water quality has deteriorated gradually due to population increase and ongoing industrialization and urbanization.In this study,multivariate statistic methods were used to assess water quality spatial pattern and to identify characteristics of water quality variation in the PRD.Water quality monitoring of the PRD during the year 2005 and 2008 was conducted at 25 different stations.Seventeen water quality parameters were analyzed for further studying.Results of one-way analysis of variance (ANOVA) indicated that all the parameters except air temperature,water temperature and zinc showed significant difference among monitoring stations in both dry and wet season.Monitoring stations in the PRD were separately classified into three statistically significant clusters at (Dlink/Dmax) <2 in dry and wet season,respectively.The three clusters indicated the similarity and dissimilarity of river water quality among 25 monitoring stations,corresponding to heavy pollution,moderate pollution and slight pollution.Thus,the results of this study are useful to evaluate water quality and manage water resources in the PRD.

  12. Quantifying the effects of tidal amplitude on river delta network flow partitioning

    Science.gov (United States)

    Hiatt, M. R.; Sendrowski, A.; Passalacqua, P.

    2014-12-01

    Deltas are generally classified as river-, tide-, or wave-dominated systems, but the influences of all environmental forces cannot be ignored when fully addressing the dynamics of the system. For example, in river-dominated deltas, river flow from the feeder channel acts as the primary driver of dynamics within the system by delivering water, sediment, and nutrients through the distributary channels, but tides and waves may affect their allocation within the network. There has been work on the asymmetry of environmental fluxes at bifurcations, but relatively few studies exist on the water partitioning at the network scale. Understanding the network and environmental effects on the flux of water, sediment, and nutrients would benefit delta restoration projects and management practices. In this study, we investigate the allocation of water flow among the five major distributary channels at Wax Lake Delta (WLD), a micro-tidal river-dominated delta in coastal Louisiana, and the effects of tidal amplitude on distributary channel discharges. We collect and compare discharge results from acoustic Doppler current profiler (ADCP) velocity transects between spring and neap tide and between falling and rising tide. The results show that discharges increased from spring to neap tide and from rising to falling tide. We investigate the spatial gradients of tidal influence within the network and validate hydraulic geometry relations for tidally influenced channels. Our results give insight into the control of network structure on flow partitioning and show the degree of tidal influence on channel flow in the river-dominated WLD.

  13. Cyclone Nargis survey in Myanmar's Ayeyarwady River delta

    Science.gov (United States)

    Fritz, H. M.; Blount, C.; Thwin, S.; Thu, M. K.; Chan, N.

    2008-12-01

    Tropical cyclone Nargis (Cat. 4) made landfall on May 2, 2008, causing the worst natural disaster in Myanmar's recorded history. Official death toll estimates exceed 130,000 fatalities making it the 7th deadliest cyclone ever recorded worldwide. Nargis took a rare nearly eastern track over the Bay of Bengal while developing sustained winds over 210 km/h with gusts up to 260 km/h hours prior to landfall in Myanmar at untypically low latitude near 16°N. It then proceeded northeast and approximately 12 hours later weakened to a Category 1 storm with sustained wind speeds of 130 km/h as it passed over Yangon. The first independent storm surge reconnaissance team was deployed to Myanmar from 9 to 23 August 2008. Cyclone Nargis struck low-lying coastal plains particularly vulnerable to storm surge flooding due to the lack of effective barriers. The team surveyed coastal and inland villages from Pyapon to Purian Point, encompassing the Bogale and Ayeyarwady River mouths. The survey by boat spanned more than 150 km parallel to the cyclone track between Pyapon and Pyinkhayan encompassing 20 hardest hit settlements such as Pyinsalu. More than 1m vertical erosion and 150 m land loss were measured at various coastal locations such as Aya. Massive deforestation of mangroves and land use were documented. Maximum storm surge elevations and overland flow depths were measured based on water marks on buildings, scars on trees, and rafted debris. The storm surge peaked in the landfall area south of Pyinkhayan and eastwards in Pyinsalu exceeding 5m. Storm waves more than 2m high were superimposed on the storm surge level in most areas according to eyewitnesses. Inundation distances reached beyond 50 km inland. Catastrophic peak fatality rates exceeded 80% in hardest hit villages with the majority being children and women. The high water marks and fatality rates significantly exceeded corresponding 2004 Indian Ocean tsunami values at every location. Eyewitnesses were interviewed to

  14. EAARL Coastal Topography-Pearl River Delta 2008: First Surface

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Miner, Michael D.; Michael, D.; Yates, Xan; Bonisteel, Jamie M.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the University of New Orleans (UNO), Pontchartrain Institute for Environmental Sciences (PIES), New Orleans, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Pearl River Delta in Louisiana and Mississippi, acquired March 9-11, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the

  15. EAARL Coastal Topography-Pearl River Delta 2008: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Miner, Michael D.; Yates, Xan; Bonisteel, Jamie M.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the University of New Orleans (UNO), Pontchartrain Institute for Environmental Sciences (PIES), New Orleans, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Pearl River Delta in Louisiana and Mississippi, acquired March 9-11, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the

  16. Polycyclic aromatic hydrocarbons increase in Athabasca River Delta sediment: temporal trends and environmental correlates.

    Science.gov (United States)

    Timoney, Kevin P; Lee, Peter

    2011-05-15

    The Athabasca River in Alberta, Canada, flows north through an area undergoing extensive bitumen resource extraction and processing before discharging its water and sediments into the Athabasca Delta and Lake Athabasca. Polycyclic aromatic hydrocarbons (PAHs) have been identified as an environmental concern in the region. We analyzed environmental data collected by the Regional Aquatics Monitoring Program and government agencies to determine whether temporal trends exist in the concentration of sediment PAHs in the Athabasca River Delta. We then determined what environmental factors related to the trends in sediment PAH concentrations. Total PAH concentrations in the sediment of the Athabasca River Delta increased between 1999 and 2009 at a rate of 0.05 mg/kg/yr ± 0.02 s.e. Annual bitumen production and mined sand volume, extent of landscape disturbance, and particulate emissions were correlated with sediment PAH concentrations as were total organic carbon in sediment and discharge of the Clearwater River, a major tributary of the Athabasca River. Within four tributaries of the Athabasca River, only the Clearwater River showed a significant correlation between discharge and sediment PAH concentration at their river mouths. Carefully designed studies are required to further investigate which factors best explain variability in sediment PAH concentrations.

  17. Geomorphology of the Chippewa River delta of Glacial Lake Saginaw, central Lower Michigan, USA

    Science.gov (United States)

    Connallon, Christopher B.; Schaetzl, Randall J.

    2017-08-01

    We introduce, characterize, and interpret the geomorphic history of a relict, Pleistocene-aged delta of the Chippewa River in central Lower Michigan. The broad, sandy Chippewa delta developed into various stages of Glacial Lake Saginaw, between ca. ≈ 17 and 15 ka·BP (calibrated ages). Although the delta was first identified in 1955 on a statewide glacial geology map, neither its extent nor its Pleistocene history had been previously determined. The delta is typically forested, owing to its wet, sandy soils, which stand out against the agricultural fields of the surrounding, loamy lake plain sediments. The delta heads near the city of Mt Pleasant and extends eastward onto the Saginaw Lowlands, i.e., the plain of Glacial Lake Saginaw. Data from 3285 water well logs, 180 hand augered sites, and 185 points randomly located in a GIS on two-storied (sand over loam) soils were used to determine the extent, textural properties, and thickness of the delta. The delta is ≈ 18 km wide and ≈ 38 km long and is sandy throughout. Deltaic sediments from neighboring rivers that also drained into Glacial Lake Saginaw merge with the lower Chippewa delta, obscuring its boundary there. The delta is thickest near the delta's head and in the center, but thins to 1-2 m or less on its eastern margins. Mean thicknesses are 2.3-2.9 m, suggestive of a thin sediment body, frequently impacted by the waves and fluctuating waters of the lakes. Although beach ridges are only weakly expressed across the delta because of the sandy sediment, the coarsest parts of the delta are generally coincident with some of these inferred former shorezones and have a broad, incised channel that formed while lake levels were low. The thick upper delta generally lies above the relict shorelines of Glacial Lakes Saginaw and Arkona (≈ 17.1 to ≈ 16 ka·BP), whereas most of the thin, distal delta is associated with Glacial Lake Warren (≈ 15 ka·BP). Together, these data suggest that the Chippewa delta formed

  18. Geomorphology and environmental dynamics in Save River delta, Mozambique : A cross-timescale perspective

    OpenAIRE

    2016-01-01

    Long-term perspectives on the evolution of river deltas have provided useful knowledge capable of responding to pending questions related to the ongoing climate and environmental changes. Increasing utilization pressure on delta environments has necessitated increased attention to protect the socio-economic and ecological values. As a result, multiple local initiatives have been designed, aimed at mitigating environmental deterioration and implementing adaptive measures, but many such initiat...

  19. Evolution characteristics of the precipitation in the Yangtze River delta based on the probability density

    Institute of Scientific and Technical Information of China (English)

    Zeng Hong-Ling; Gao Xin-Quan; Zhang Wen

    2005-01-01

    In this paper the dryness/wetness (DW) grade data of the Yangtze River delta is transformed into the temporal evolution of precipitation probability (PP), and its hierarchically distributive characters are revealed. Research results show that the precipitation of the Yangtze River delta displays the interannual, interdecadal, as well as longer quasiperiodic changes than a century, and all the periods have a confidence level of more than 0.05. In the DW grade series of 530 years, although the frequency of the small probability events (SPEs) of drought/flood in each area of the Yangtze River delta is different, the frequency of the SPEs triggered by the climatic background state is yet the same. This research result fully shows the significant impact of the climatic evolution as a background state upon the occurrence of SPEs, which will be instructive in climatic prediction theory and in raising the accuracy of the climatic prediction.

  20. Petroleum Hydrocarbon Degradation Potential of Soil Bacteria Native to the Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    WANG Zhen-Yu; GAO Dong-Mei; LI Feng-Min; ZHAO Jian; XIN Yuan-Zheng; S.SIMKINS; XING Bao-Shan

    2008-01-01

    The bioremediation potential of bacteria indigenous to soils of the Yellow River Delta in China was evaluated as a treatment option for soil remediation. Petroleum hydrocarbon degraders were isolated from contaminated soil samples from the Yellow River Delta. Four microbial communities and eight isolates were obtained. The optimal temperature, salinity, pH, and the ratios of C, N, and P (C:N:P) for the maximum biodegradation of diesel oil, crude oil, n-alkanes, and polyaromatic hydrocarbons by ndigenous bacteria were determined, and the kinetics changes in microbial communities were monitored. In general, the mixed microbial consortia demonstrated wider catabolic versatility and faster overall rate of hydrocarbon degradation than individual isolates. Our experimental results demonstrated the feasibility of biodegradation of petroleum hydrocarbon by indigenous bacteria for oil remediation in the Yellow River Delta.

  1. Tows Matrix Analysis on Developing Urban Agriculture in the Pearl River Delta Area

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on the introduction of the profile of Pearl River Delta area, the strengths, weaknesses, opportunities and threats of developing urban agricultural in Pearl River Delta area are analyzed by using the SWOT analysis. The strengths are analyzed from three aspects, covering natural resources, geographic advantages and technological advantages; the weaknesses are analyzed from the terms of land resources, labor cost, industrial scale and quality of personnel involved; opportunities are analyzed from the aspects of potential clients, favorable policies and markets; the threats are analyzed from two aspects, including concept factor and income gap between urban and rural areas. on the basis of the above analyses, the countermeasures and suggestions on the development of urban agriculture in the Pearl River Delta area are put forward.

  2. River-Delta Systems:A Significant Deposition Location of Global Coal-Measure Source Rocks

    Institute of Scientific and Technical Information of China (English)

    Yunhua Deng

    2016-01-01

    Natural gas is providing a larger proportion of primary energy, and will soon surpass oil to become the most important fossil fuel. There are various genetic types of natural gas of which the type that pyrolysed or cracked from humic kerogen accounts for 70% of presently discovered global natural gas reserves. The parent material of humic kerogen is higher multi-cellular plants. Investigations of offshore basins in China, Russia, Indonesia, Bangladesh, Australia, Egypt and Na-mibia show that river-delta systems contain the major sources of coal-type gas. Sand and mud carried by rivers form deltas at river mouths and fertile soil of these deltas encourages the long-term growth of higher plants. Autochthonous higher plants and allochthonous terrigenous phytoclasts contribute to the formation of coal, carbargilite and dark mudstone, which are potential parent materials of natural gas and the basis of coal-type gas generation.

  3. Targeting Pearl River Delta, Untied Airlines Expect Direct Line to Guangzhou

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ With the fast economy growth,Guangzhou and Pearl River Delta has become a key market in China.To provide better service for this market, the United Airlines took the leading role to set up an office in Guangzhou in April, 2004. At the end of last year, the United Airlines opened the ferry service between five ports in Pearl River Delta and the Sky Pier of Hong Kong International Airport by using the fast ferryboat and successfully realized the seamless connection.At present, for there is not direct flight from Guangzhou to the U. S., the United Airlines uses the ferry boat to connect Pearl River Delta to Hong Kong International Airport.

  4. River delta network hydraulic residence time distributions and their role in coastal nutrient biogeochemistry

    Science.gov (United States)

    Hiatt, M. R.; Castaneda, E.; Twilley, R.; Hodges, B. R.; Passalacqua, P.

    2015-12-01

    River deltas have the potential to mitigate increased nutrient loading to coastal waters by acting as biofilters that reduce the impact of nutrient enrichment on downstream ecosystems. Hydraulic residence time (HRT) is known to be a major control on biogeochemical processes and deltaic floodplains are hypothesized to have relatively long HRTs. Hydrological connectivity and delta floodplain inundation induced by riverine forces, tides, and winds likely alter surface water flow patterns and HRTs. Since deltaic floodplains are important elements of delta networks and receive significant fluxes of water, sediment, and nutrients from distributary channels, biogeochemical transformations occurring within these zones could significantly reduce nutrient loading to coastal receiving waters. However, network-scale estimates of HRT in river deltas are lacking and little is known about the effects of tides, wind, and the riverine input on the HRT distribution. Subsequently, there lacks a benchmark for evaluating the impact of engineered river diversions on coastal nutrient ecology. In this study, we estimate the HRT of a coastal river delta by using hydrodynamic modeling supported by field data and relate the HRT to spatial and temporal patterns in nitrate levels measured at discrete stations inside a delta island at Wax Lake Delta. We highlight the control of the degree of hydrological connectivity between distributary channels and interdistributary islands on the network HRT distribution and address the roles of tides and wind on altering the shape of the distribution. We compare the observed nitrate concentrations to patterns of channel-floodplain hydrological connectivity and find this connectivity to play a significant role in the nutrient removal. Our results provide insight into the potential role of deltaic wetlands in reducing the nutrient loading to near-shore waters in response to large-scale river diversions.

  5. Song Hong (Red River) delta evolution related to millennium-scale Holocene sea-level changes

    Science.gov (United States)

    Tanabe, Susumu; Hori, Kazuaki; Saito, Yoshiki; Haruyama, Shigeko; Vu, Van Phai; Kitamura, Akihisa

    2003-11-01

    The Song Hong (Red River) delta occurs on the northwest coast of the South China Sea. Its evolution in response to Holocene sea-level changes was clarified on the basis of sedimentary facies and 14 radiocarbon dates from the 40 m long Duy Tien core from the delta plain, and using previously reported geological, geomorphological, and archaeological data. The delta prograded into the drowned valley as a result of early Holocene inundation from 9 to 6 cal. kyr BP, as sea-level rise decelerated. The sea-level highstand at +2-3 m from 6 to 4 cal. kyr BP allowed widespread mangrove development on the delta plain and the formation of marine notches in the Ha Long Bay and Ninh Binh areas. During sea-level lowering after 4 cal. kyr BP, the former delta plain emerged as a marine terrace, and the delta changed into the present tide- and wave-influenced delta with accompanying beach ridges. Delta morphology, depositional pattern, and sedimentary facies are closely related to Holocene sea-level changes. In particular, falling sea level at 4 cal. kyr BP had a major impact on the evolution of the Song Hong delta, and is considered to be linked to climate changes.

  6. Linking rapid erosion of the Mekong River delta to human activities

    Science.gov (United States)

    Anthony, Edward J.; Brunier, Guillaume; Besset, Manon; Goichot, Marc; Dussouillez, Philippe; Nguyen, Van Lap

    2015-10-01

    As international concern for the survival of deltas grows, the Mekong River delta, the world’s third largest delta, densely populated, considered as Southeast Asia’s most important food basket, and rich in biodiversity at the world scale, is also increasingly affected by human activities and exposed to subsidence and coastal erosion. Several dams have been constructed upstream of the delta and many more are now planned. We quantify from high-resolution SPOT 5 satellite images large-scale shoreline erosion and land loss between 2003 and 2012 that now affect over 50% of the once strongly advancing >600 km-long delta shoreline. Erosion, with no identified change in the river’s discharge and in wave and wind conditions over this recent period, is consistent with: (1) a reported significant decrease in coastal surface suspended sediment from the Mekong that may be linked to dam retention of its sediment, (2) large-scale commercial sand mining in the river and delta channels, and (3) subsidence due to groundwater extraction. Shoreline erosion is already responsible for displacement of coastal populations. It is an additional hazard to the integrity of this Asian mega delta now considered particularly vulnerable to accelerated subsidence and sea-level rise, and will be exacerbated by future hydropower dams.

  7. Loess-like deposits in the Pearl River delta area, southeast China

    Science.gov (United States)

    Wang, Jing; Chen, Guoneng; Peng, Zhuolun; Grapes, Rodney

    2015-12-01

    A layer of yellow silt is widely distributed in the late Quaternary succession of the Pearl River delta, southeast China. A representative section at Xi Lingang was analyzed using particle size analysis, scanning electron microscope observation, geochemical analysis and OSL dating to determine the characteristics and genesis of the yellow silt. Grain size composition of the yellow silt is homogeneous and comparable to typical north China loess (10-50 μm as "basic grain size group", Pearl River delta area is also derived from a northwest China provenance.

  8. Characteristics and Process of Land Use Changes in the Yangtze River Delta, China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    As one of the developing countries China has an arable land per capita far below the world's average level. With a high-density population and the quick development of economy and urbanization, the Yangtze River Delta shows the typical characteristics of land use in developed regions of China, which are: high land reclamation rate and low arable land per capita; intensive land use and high output value; and rapid increasing of construction land area and fast diminishing of arable lands. The analysis indicates that the process of the arable land changes in the Yangtze River Delta could be divided into four different change stages over the past 50 years.

  9. Tidal impacts on the subtidal flow division at the main bifurcation in the Yangtze River Delta

    Science.gov (United States)

    Zhang, Wei; Feng, Haochuan; Hoitink, A. J. F.; Zhu, Yuliang; Gong, Fei; Zheng, Jinhai

    2017-09-01

    Flow division at bifurcations in the Yangtze Estuary has received ample attention, since it may control the pathways of terrestrial sediments over downstream river branches including the 12.5 m Deepwater Navigation channel. While some efforts have been made to interpret flow division at the bifurcations of the Yangtze Estuary, little attention has been paid to the role of tides. Flow division at estuarine bifurcations is made complicated by tides that propagate from the outlet of the tidal channels into the delta. To quantify the tidal influence on the distribution of river discharge, and more generally, to understand the mechanisms governing the subtidal flow division at the tidally affected bifurcation in the Yangtze River Delta, a two-dimensional hydrodynamic model is employed. In this model, the landward boundary is chosen beyond the tidal limit, where the tidal motion has faded out entirely. The seaward boundary is chosen such that the river discharge does not influence the water level. Subtidal discharges are decomposed using the method of factor separation, to distinguish between the effects of tides, river discharge and river-tide interactions on the subtidal flow division. Results indicate that tides modify the river discharge distribution over distributary channels in the Yangtze River Delta, particularly in the dry season. A significant difference in the subtidal flow division during spring tide and neap tide shows that the tidally averaged flow division over the distributaries in the delta greatly depends on tidal amplitude. By varying the river discharge at the landward boundary and amplitudes and phases of the principal tidal constituents at the seaward boundary of the established model, the sensitivities of the subtidal flow division to the river discharge and tidal amplitude variation were investigated in detail. Generally, the tidal impacts on the subtidal flow division are around 12% to 22%, with river discharge varying from 30,000 m3s-1 to 20

  10. Effect of tides, river flow, and gate operations on entrainment of juvenile salmon into the interior Sacramento–San Joaquin River Delta

    Science.gov (United States)

    Perry, Russell W.; Brandes, Patricia L.; Burau, Jon R.; Sandstrom, Philip T.; Skalski, John R.

    2015-01-01

    Juvenile Chinook Salmon Oncorhynchus tshawytscha emigrating from natal tributaries of the Sacramento River, California, must negotiate the Sacramento-San Joaquin River Delta (hereafter, the Delta), a complex network of natural and man-made channels linking the Sacramento River with San Francisco Bay. Fish that enter the interior and southern Delta—the region to the south of the Sacramento River where water pumping stations are located—survive at a lower rate than fish that use alternative migration routes. Consequently, total survival decreases as the fraction of the population entering the interior Delta increases, thus spurring management actions to reduce the proportion of fish that are entrained into the interior Delta. To better inform management actions, we modeled entrainment probability as a function of hydrodynamic variables. We fitted alternative entrainment models to telemetry data that identified when tagged fish in the Sacramento River entered two river channels leading to the interior Delta (Georgiana Slough and the gated Delta Cross Channel). We found that the probability of entrainment into the interior Delta through both channels depended strongly on the river flow and tidal stage at the time of fish arrival at the river junction. Fish that arrived during ebb tides had a low entrainment probability, whereas fish that arrived during flood tides (i.e., when the river's flow was reversed) had a high probability of entering the interior Delta. We coupled our entrainment model with a flow simulation model to evaluate the effect of nighttime closures of the Delta Cross Channel gates on the daily probability of fish entrainment into the interior Delta. Relative to 24-h gate closures, nighttime closures increased daily entrainment probability by 3 percentage points on average if fish arrived at the river junction uniformly throughout the day and by only 1.3 percentage points if 85% of fish arrived at night. We illustrate how our model can be used to

  11. Tissue residues and hazards of water-borne pesticides for federally listed and candidate fishes of the Sacramento-San Joaquin River Delta, California: 1993-1995

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Sacramento-San Joaquin Delta is formed at the confluence of the south-flowing Sacramento River and the north-flowing San Joaquin River. The Delta provides...

  12. Extreme value analysis of annual maximum water levels in the Pearl River Delta, China

    Institute of Scientific and Technical Information of China (English)

    Qiang ZHANG; Chong-Yu XU; Yongqin David CHEN; Chun-ling LIU

    2009-01-01

    We analyzed the statistical properties of water level extremes in the Pearl River Delta using five probability distribution functions. Estimation of para-meters was performed using the L-moment technique.Goodness-of-fit was done based on Kolmogorov-Smirnov's statistic D (K-S D). The research results indicate that Wakeby distribution is the best statistical model for description of statistical behaviors of water level extremes in the study region. Statistical analysis indicates that water levels corresponding to different return periods and associated variability tend to be larger in the landward side of the Pearl River Delta and vice versa. A ridge characterized by higher water level can be identified expanding along the West River and the Modaomen channel, showing the impacts of the hydrologic process of the West River basin. Trough and higher grades of water level changes can be detected in the region drained by Xi'nanyong channel, Dongping channel, and mainstream of Pearl River. The Pearl River Delta region is character-ized by low-lying topography and a highly-advanced socio-economy, and is heavily populated, being prone to flood hazards and flood inundation due to rising sea level and typhoons. Therefore, sound and effective counter-measures should be made for human mitigation to natural hazards such as floods and typhoons.

  13. Preliminary occurrence studies of antibiotic residues in Hong Kong and Pearl River Delta.

    Science.gov (United States)

    Chen, Yumei; Leung, Kelvin Sze-Yin; Wong, Jonathan Woon-Chung; Selvam, Ammaiyappan

    2013-01-01

    An improved liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to investigate the occurrence of selected antibiotic residues in Hong Kong and Pearl River Delta. LC and MS parameters were optimized to produce the maximum analytical responses for each compound. The established method targeted five groups of antibiotics, namely, macrolides, sulfonamides, tetracyclines, quinolones, and amphenicols. The method was validated for three types of environmental water matrices, namely, reservoir, river, and estuarine waters. Low detection limits of 0.17-0.18 ng/L for macrolides, 0.22-0.34 ng/L for quinolones, 0.67-1.65 ng/L for tetracyclines, and 0.27-0.56 ng/L for sulfonamides were obtained. No apparent interferences were observed in the chromatograms of all antibiotics groups. The developed method was preliminarily used to analyze water samples collected from Yuen Long River in New Territories, Hong Kong and four sites along the Pearl River Delta. Results showed that high level of tetracycline was found among the groups tested in the local river samples. In Pearl River Delta, we identified significant levels of erythromycin, roxithromycin, and sulfadiazine in Shenzhen Reservoir.

  14. Estimating the submarine groundwater and nutrients discharge of Yellow River delta with cross-section method.

    Science.gov (United States)

    Liu, Guanqun; Wang, Juan; Yuan, Ruiqiang; Sun, Beibei; Zhu, Liangchao; Wang, Yansi

    2010-01-01

    In this paper, cross-section method was used to estimate the groundwater and nutrients discharge fluxing to the Bohai Sea from the Yellow River Delta. The flux of shallow phreatic groundwater (within 10 m) in the Yellow River Farm discharging into sea was 2.9x10(-5) m3/m d in 2004 and 3.1x10(-5) m3/m d in 2005. Time distribution monthly mean flux is consistent with the Yellow River's runoff but taking on lag effect. And the volume of the phreatic water discharging from the whole delta is 3.71-3.77x10(3) m3, which is 2x10(-5)% of the Yellow River's annual runoff. The transport amount of shallow confined water (buried depth 15-20 m) from 2004 to 2005 was 5.7-6.2x10(-3) m3/m d in the Yellow River delta, 0.0037-0.004% of the runoff of Yellow River. There is low concentration of NO3-, NH4+ and PO4(3-) but high dissolved SiO2 in the shallow confined aquifer. Despite the high concentration of phreatic nitrate, it weakly influences the seawater because of the little flux of discharge into sea.

  15. Late Holocene depositional environments and coastal evolution of the Mekong River Delta, Southern Vietnam

    Science.gov (United States)

    Lap Nguyen, Van; Ta, Thi Kim Oanh; Tateishi, Masaaki

    2000-08-01

    The Mekong River Delta in Southern Vietnam is a tide-dominated delta and has been formed by the Mekong River system. The sediments are dominantly fine grained and were deposited in the receiving basin with slight inclination of pre-existing deposits in the South China Sea and Gulf of Thailand. Around 6000 to 5000 yr BP maximum Holocene transgression occurred and seawaves surrounded uplands of the Late Pleistocene terrace, basement rock and weathered land in the northern parts of the delta. Double notches were undercut by seawaves on the limestone hill in Hatien at about 4.5 and 2.5 m above present sea level. Marine deposits prevailed throughout the delta. During the highstand and regressions of relative sea level over the last 4550 yr BP, delta progradation has produced a great flat-plain of 62,520 km 2. This extremely fast progradation could be due to: (a) very high sediment supply depositing in the slight inclination of the receiving basin; (b) neotectonic movements and relative sea-level changes; (c) widespread mangrove forests playing an important role to enhance sediment accumulation. Former mangrove marshy deposits were significantly developed in the Plain of Reeds and Longxuyen Quadrangle. Mangrove marshes have also been developing well in the Camau Peninsula and present coastlines. Moreover, regressions over the last 4550 yr BP have produced many distinct sets of relict beach ridges which are useful in distinguishing the former coastlines and evolutionary history of the delta.

  16. Detection of Area Changes in River Mouthbars at the Mekong River Delta using ALOS/PALSAR data

    Science.gov (United States)

    Tanaka, A.; Uehara, K.; Tamura, T.; Saito, Y.

    2011-12-01

    Projected sea-level rise by the year 2100 would be ~1m recently and its negative impact on the coastal zone has been pointed out, particularly for mega-deltas in Asia by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC, 2007). The relative sea-level rise varies with specific conditions and processes over broad spatial and temporal scales. Therefore, long-term monitoring of geomorphological changes in coastal areas over wide areas is of highly interest and importance for coastal management. However, due to limited data availability and accessibility in developing countries, there is not enough systematic coastal monitoring. The Mekong River Delta is one of typical mega-deltas in Asia, which has a low-lying wide delta-plain located in Cambodia to South Vietnam. Sediment and water discharges of the Mekong River are controlled by the monsoon with high and low discharge in summer (wet season) and winter (dry season), respectively. Therefore, technologies such as SAR (Synthetic Aperture Radar) not affected by the cloud conditions offer potential for monitoring in the monsoon Asia region. In this study, ALOS (Advanced Land Observing Satellite) PALSAR (Phased Array type L-band SAR) data acquired over a period from December 2006 to January 2011 are analyzed to investigate the relation between the sea level and the shape of mouthbars in the Mekong River. Level-1.0 PALSAR data were processed, coregistered, and geocoded to make SAR backscatter intensity images. River mouthbars with strong backscatter, which is surrounded by the water with weak backscatter, are successfully extracted using a histogram thresholding algorithm. Estimated areas of river mouthbars, which are located at the central part of the delta and openly faced to the South China Sea, gradually increase on an annual time scale. These river mouthbars are growing to the seaward. Besides this overall increasing trend, seasonal variations of areas are observed; these correlate with

  17. Wang Jinzhen Attended the Forum on Cooperation & Development between Yangtze River Delta and Baltic Sea Region

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ On October 17,on behalf of CCPIT,Vice-Chairman Wang Jinzhen attended the opening ceremony of the 3rd Forum on Cooperation & Development between Yangtze River Delta Region of China and Baltic Sea Region of Europe,where he delivered a speech.

  18. Private Challenges to Public Dominance: The Resurgence of Private Education in the Pearl River Delta.

    Science.gov (United States)

    Mok, Ka-Ho

    1997-01-01

    Examines the policy context in which private education has emerged in post-Mao China. Uses three case studies of private schools/colleges to explore how intellectuals and educators in the Pearl River Delta (Guangdong province) have persevered to assert their academic independence, offer a new agenda for education, and redefine the private-public…

  19. Changing spatial concentration of sectoral employment in China’s Pearl River Delta 1990 - 2005

    NARCIS (Netherlands)

    Cheng, Fangfang; Boerboom, Luc; Geertman, Stan; Hooimeijer, Pieter

    2013-01-01

    Using county-level employment data, we analyse how the spatial concentration of jobs has changed in China's Pearl River Delta (PRD) between 1990 and 2005. Despite unique Chinese policies that exhibit strong influence on the economic landscape, we detect key parallels with the patterns found in class

  20. Sources of excess urban carbonaceous aerosol in the Pearl River delta region, China

    Science.gov (United States)

    Carbonaceous aerosol is one of the important constituents of fine particulate matter (PM2.5) in Southern China, including the Pearl River Delta (PRD) region and Hong Kong (HK). During the study period (October and December of 2002, and March and June of 2003), the monthly average...

  1. Changing spatial concentrations of sectorial employment in China's Pearl River Delta

    NARCIS (Netherlands)

    Cheng, F.; Boerboom, L.; Geertman, S.C.M.; Hooimeijer, P.

    2012-01-01

    Using county-level employment data, we analyse how the spatial concentration of jobs has changed in China’s Pearl River Delta (PRD) between 1990 and 2005. Despite unique Chinese policies that exhibit strong influence on the economic landscape, we detect key parallels with the patterns found in class

  2. Analysis on the Evolution of Agricultural Structure about Pan-Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    DAI Jiang; LIU Zhi-ying

    2010-01-01

    Starting from the definition of agricultural structure,this paper firstly analyzes the change of industrial and spatial structure of agriculture of Pan-Yangtze River Delta,then inspects the relationship between the development of economics and the evolution of agricultural structure,an the end it provides policy recommendation about the development and adjustment of agricultural structure for the future.

  3. Changing spatial concentrations of sectorial employment in China's Pearl River Delta

    NARCIS (Netherlands)

    Cheng, F.; Boerboom, L.; Geertman, S.C.M.; Hooimeijer, P.

    2012-01-01

    Using county-level employment data, we analyse how the spatial concentration of jobs has changed in China’s Pearl River Delta (PRD) between 1990 and 2005. Despite unique Chinese policies that exhibit strong influence on the economic landscape, we detect key parallels with the patterns found in

  4. Numerical simulation and analysis of saltwater intrusion lengths in the Pearl River Delta, China

    NARCIS (Netherlands)

    Zhang, W.; Feng, H.; Zheng, J.; Hoitink, A.J.F.; Vegt, van der M.; Zhu, Y.; Cai, H.

    2013-01-01

    In recent years, large-scale saltwater intrusion has been threatening the freshwater supply in the metropolitan cities surrounding the Pearl River delta (PRD). Therefore, a better understanding of the saltwater intrusion process in this region is necessary for local water resource management. In thi

  5. 2009-2010 USACE Vicksburg District Lidar: Mississippi River Delta Phase I

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — LiDAR collected at 1.0 points per square meter (1.0m GSD) for the entire portion of the Mississippi River Delta in the Vicksburg District. This area was flown...

  6. Developing Permanent Vegetable Production Systems for the Red River Delta, Vietnam

    NARCIS (Netherlands)

    Pham Thi Thu Huong, Huong; Everaarts, A.P.; Neeteson, J.J.; Struik, P.C.

    2012-01-01

    The year-round demand for commercially produced vegetables in South-East Asia is growing rapidly because of ongoing population growth and urbanisation. Vegetable production plays an important role in the rural economy of the Red River Delta, the economic centre of northern Vietnam. Field vegetables,

  7. Potential Activity of Subglacial Microbiota Transported to Anoxic River Delta Sediments

    DEFF Research Database (Denmark)

    Cameron, Karen A.; Stibal, Marek; Olsen, Nikoline S.

    2017-01-01

    The Watson River drains a portion of the SW Greenland ice sheet, transporting microbial communities from subglacial environments to a delta at the head of Søndre Strømfjord. This study investigates the potential activity and community shifts of glacial microbiota deposited and buried under layers...

  8. SPATIO-TEMPORAL VARIATION OF MERCURY IN BIDYADHARI RIVER OF SUNDARBAN DELTA, INDIA

    Directory of Open Access Journals (Sweden)

    Shivaji Bhattacharya

    2014-06-01

    Full Text Available Bidyadhari river originates in Nadia district of West Bengal, India and then flows through North 24 Parganas district and now serves as a sewage and excess rainwater outlet from the city of Kolkata and adjacent area, which ultimately empties at the Bay of Bengal through the Indian Sundarban delta. Four different stations situated around the course of the river at considerable distances have been selected from the outfall of sewage canals at Kulti-Ghushighata (S1, where metropolitan sewages discharged and mixed up into water of Bidyadhari river, which ultimately carried through this river via stations Malancha (S2, Kanmari (S3 to Dhamakhali (S4, just before the river confluences with the larger Raimangal river at northern Sundarban delta. This study was conducted to estimate total mercury (Hg concentration in waters (during high tides and ebb tides and sediments of Bidyadhari river in pre-monsoon, monsoon and post-monsoon seasons during the period from March, 2012 to February, 2013 at those stations. It is revealed from the estimated data that agricultural runoff, sewage, effluents from various industries and Kolkata metropolitan, Salt Lake City and adjacent areas of North 24 Parganas district carried and discharged in Bidyadhari river through sewage canals are not so high in mercury content for sediment contamination but alarming in respect of water quality, which crosses the permissible limit of Hg for consumption (0.001 ppm in wide range of areas at Kanmari and Dhamakhali around the estuary. Enhancement of Hg level in this river water and transportation of the metal through tidal effects to and fro mangrove land of Sundarban may be dangerous for aquatic lives and supposed to be grave concern for the ecology of the Sundarban delta including humans

  9. Recent morphological changes in the Mekong and Bassac river channels, Mekong delta: The marked impact of river-bed mining and implications for delta destabilisation

    Science.gov (United States)

    Brunier, Guillaume; Anthony, Edward J.; Goichot, Marc; Provansal, Mireille; Dussouillez, Philippe

    2014-11-01

    The Mekong delta, in Vietnam, is the world's third largest delta. Densely populated, the delta has been significantly armoured with engineering works and dykes to protect populations and infrastructure from storms, and shrimp farms from saltwater intrusion. Considerable development pressures in Vietnam and in the upstream countries have resulted in the construction of several dams in China and in important channel-bed aggregate extractions especially in Cambodia. The effects of these developments impact the delta dynamics in various ways. In this study, changes in the channel morphology of the Mekong proper and the Bassac, the two main distributaries in the 250 km-long deltaic reach from the Cambodian border to the coast, were analysed using channel depth data for 1998 and 2008. The channels display important and irregular bed changes over the 10-year comparison period, including significant incision and expansion and deepening of numerous pools. The mean depth of both channels increased by more than 1.3 m. Both channels also showed correlative significant bed material losses: respectively 90 million m3 in the Mekong and 110 million m3 in the Bassac over the 10-year period. These important losses over a relatively short period, and weak correlations between bed incision and hydraulic parameters suggest that the marked morphological changes are not in equilibrium with flow and sediment entrainment conditions, and are therefore not related to changes in river hydrology. We claim that aggregate extraction, currently practised on a very large scale in the Mekong delta channels and upstream of the delta, is the main cause of these recent morphological changes. These changes are deemed to contribute actively to rampant bank erosion in the delta as well as to erosion of the Mekong delta shoreline. Other contributory activities include the numerous dykes and embankments. The role of existing dams in bed losses remains unclear in the absence of reliable data on the Mekong

  10. Mapping the change of Phragmites australis live biomass in the lower Mississippi River Delta marshes

    Science.gov (United States)

    Ramsey, Elijah W.; Rangoonwala, Amina

    2017-07-28

    Multiyear remote sensing mapping of the normalized difference vegetation index (NDVI) was carried out as an indicator of live biomass composition of the Phragmites australis (hereafter Phragmites) marsh in the lower Mississippi River Delta (hereafter delta) from 2014 to 2017. Maps of NDVI change showed that the Phragmites condition was fairly stable between May 2014 and July 2015. From July 2015 to April 2016 NDVI change indicated Phragmites suffered a widespread decline in the live biomass proportion.  Between April and September 2016, most marsh remained unchanged from the earlier period or showed improvement; although there were pockets of continued decline scattered throughout the lower delta. From September 2016 to May 2017 a pronounced and widely exhibited decline in the condition of Phragmites marsh again occurred throughout the lower delta. This final NDVI change mapping supported field observations of Phragmites decline during the same period.

  11. Dispersal of larval suckers at the Williamson River Delta, Upper Klamath Lake, Oregon, 2006-09

    Science.gov (United States)

    Wood, Tamara M.; Hendrixson, Heather A.; Markle, Douglas F.; Erdman, Charles S.; Burdick, Summer M.; Ellsworth, Craig M.; Buccola, Norman L.

    2012-01-01

    An advection/diffusion modeling approach was used to simulate the transport of larval suckers from spawning areas in the Williamson River, through the newly restored Williamson River Delta, to Upper Klamath Lake. The density simulations spanned the years of phased restoration, from 2006/2007 prior to any levee breaching, to 2008 when the northern part of the delta was reconnected to the lake, and 2009 when levees on both sides of the delta had been breached. Model simulation results from all four years were compared to field data using rank correlation. Spearman ρ correlation coefficients were usually significant and in the range 0.30 to 0.60, providing moderately strong validation of the model. The correlation coefficients varied with fish size class in a way that suggested that the model best described the distribution of smaller fish near the Williamson River channel, and larger fish away from the channel. When Lost River and shortnose/Klamath largescale suckers were simulated independently, the correlation results suggested that the model better described the transport and dispersal of the latter species. The incorporation of night-time-only drift behavior in the Williamson River channel neither improved nor degraded correlations with field data. The model showed that advection by currents is an important factor in larval dispersal.

  12. A large-scale environmental flow experiment for riparian restoration in the Colorado River delta

    Science.gov (United States)

    Shafroth, Patrick B.; Schlatter, Karen; Gomez-Sapiens, Martha; Lundgren, Erick; Grabau, Matthew R.; Ramirez-Hernandez, Jorge; Rodriguez-Burgeueno, J. Eliana; Flessa, Karl W.

    2017-01-01

    Managing streamflow is a widely-advocated approach to provide conditions necessary for seed germination and seedling establishment of trees in the willow family (Salicaceae). Experimental flow releases to the Colorado River delta in 2014 had a primary objective of promoting seedling establishment of Fremont cottonwood (Populus fremontii) and Goodding's willow (Salix gooddingii). We assessed seed germination and seedling establishment of these taxa as well as the non-native tamarisk (Tamarix spp.) and native seepwillow shrubs (Baccharis spp.) in the context of seedling requirements and active land management (land grading, vegetation removal) at 23 study sites along 87 river km. In the absence of associated active land management, experimental flows to the Colorado River delta were minimally successful at promoting establishment of new woody riparian seedlings, except for non-native Tamarix. Our results suggest that the primary factors contributing to low seedling establishment varied across space, but included low or no seed availability in some locations for some taxa, insufficient soil moisture availability during the growing season indicated by deep groundwater tables, and competition from adjacent vegetation (and, conversely, availability of bare ground). Active land management to create bare ground and favorable land grades contributed to significantly higher rates of Salicaceae seedling establishment in a river reach with high groundwater tables. Our results provide insights that can inform future environmental flow deliveries to the Colorado River delta and its ecosystems and other similar efforts to restore Salicaceae taxa around the world.

  13. Changing river courses in the western part of the Ganga-Brahmaputra delta

    Science.gov (United States)

    Rudra, Kalyan

    2014-12-01

    The Ganga-Brahmaputra delta is the largest on Earth, the product of two of the world's largest and siltiest rivers. It is formed in a basin located over the zone where the Indian plate subducts beneath the Himalaya to the north and the Indo-Burman ranges to the east. The distributaries in the south-western part of the delta remain disconnected from the Ganga-Padma during the lean season, although they are still active in bank erosion and sediment transport during the monsoon. Four distributaries of the Bhagirathi-Hugli (the westernmost branch of the Ganga) have gone dry during known historical period. In many cases, the natural decay of rivers has been exacerbated by the human intervention, especially where rivers are embanked and no allowance made for their migration through meandering and avulsion. In the coastal zone where mangroves were cleared and creeks were embanked since the late 18th century, decay of channels, and advancement of the sea towards inland have been aggravated. The subsequent attempt of flushing the sediment load to the sea from the estuary to improve the status of navigation in the Bhagirathi-Hugli River was not successful to the level of expectation. This paper deals with the decay and changing courses of rivers in the western part of the Ganga-Brahmaputra delta.

  14. A brief history and summary of the effects of river engineering and dams on the Mississippi River system and delta

    Science.gov (United States)

    Alexander, Jason S.; Wilson, Richard C.; Green, W. Reed

    2012-01-01

    The U.S. Geological Survey Forecast Mekong project is providing technical assistance and information to aid management decisions and build science capacity of institutions in the Mekong River Basin. A component of this effort is to produce a synthesis of the effects of dams and other engineering structures on large-river hydrology, sediment transport, geomorphology, ecology, water quality, and deltaic systems. The Mississippi River Basin (MRB) of the United States was used as the backdrop and context for this synthesis because it is a continental scale river system with a total annual water discharge proportional to the Mekong River, has been highly engineered over the past two centuries, and the effects of engineering have been widely studied and documented by scientists and engineers. The MRB is controlled and regulated by dams and river-engineering structures. These modifications have resulted in multiple benefits including navigation, flood control, hydropower, bank stabilization, and recreation. Dams and other river-engineering structures in the MRB have afforded the United States substantial socioeconomic benefits; however, these benefits also have transformed the hydrologic, sediment transport, geomorphic, water-quality, and ecologic characteristics of the river and its delta. Large dams on the middle Missouri River have substantially reduced the magnitude of peak floods, increased base discharges, and reduced the overall variability of intraannual discharges. The extensive system of levees and wing dikes throughout the MRB, although providing protection from intermediate magnitude floods, have reduced overall channel capacity and increased flood stage by up to 4 meters for higher magnitude floods. Prior to major river engineering, the estimated average annual sediment yield of the Mississippi River Basin was approximately 400 million metric tons. The construction of large main-channel reservoirs on the Missouri and Arkansas Rivers, sedimentation in dike

  15. Geomorphic evolution of the Lilas River fan delta (Central Evia, Greece), during the Quaternary

    Science.gov (United States)

    Karymbalis, Efthimios; Valkanou, Kanella; Tsironis, Giorgos; Tsodoulos, Ioannis; Iliopoulos, George; Tsanakas, Konstantinos; Batzakis, Vasilis

    2015-04-01

    This study deals with the geomorphic evolution of the Lilas river fan delta, which is a late Holocene fan delta with an area of about 25 km2, extended mainly towards the south Evoikos Gulf and a secondary extension of approximately 5 km2 towards the north Evoikos Gulf (Central Evia Isl., Greece). This work has combined field geomorphological mapping with the study of the stratigraphy of late Pleistocene - Holocene deltaic sediments. A detailed geomorphic map at the scale of 1:5,000 has been prepared showing both the deltaic plain and the coastal zone features using GIS techniques. Comparative interpretation of aerial photographs taken in different dates and reliable maps of the last two centuries along with field observations depict recent changes of the delta morphology. Profiles of seven drill cores up to the depth of 70 m, provided by the municipality authorities, were considered in order to study the late Pleistocene - Holocene stratigraphy of the broader fan delta plain. Additionally, two boreholes reaching the depth of 4.75 m were drilled with a portable drilling set. The stratigraphy of the late Holocene sediments was studied in detail and 41 sediment samples, collected from selected sedimentary layers, were analyzed using micropaleontological and grain size analysis methods, while samples were dated using OSL. The study of the stratigraphy of the late Holocene deltaic sediments showed that during this period the sea invaded the area of the northwestern delta and created a shallow open marine environment which at times was disturbed by multiple quiet lagoonal phases of fine sediment deposition. Geomorphological mapping showed that among the most important factor for the recent development of the delta is fluvial sedimentation. The dominant landforms in the deltaic plain are the numerous abandoned palaeochannels. The main channel of the river changed its course several times leading to the building and subsequent abandonment of at least four fan delta lobes

  16. Heavy Metals and Biogenic Elements in Aquatic Systems of the Don River Delta

    Science.gov (United States)

    Tkachenko, Anna; Tkachenko, Oleg

    2014-05-01

    River deltas are located in the lower parts of the cascade landscape-geochemical systems of the river basins, so their geochemical conditions often characterize the anthropogenic impact on whole river system. The Don River runs through the one of the most agriculturally developed and densely populated area of Russia, and flows into the Azov Sea - the smallest and shallowest sea in the world. These factors determine the geochemical features of aquatic systems of the Don River mouth area and the specificity of the "river-sea" geochemical barrier zone. The paper presents results of the field studies of the geochemical structure of the Don River mouth area, which were conducted in frames of the RFBR project in 2012-2013. Major types of the deltaic water streams and bodies were studied in different hydrological seasons: spring floods, summer, autumn and winter low water periods. About 50 samples of water, suspended matter and 60 samples of bottom sediments have been collected and analyzed for heavy metals (Fe, Mn, Zn, Cu, Ni, Co, Pb, Cr, Cd etc.) and biogenic elements (nitrate, nitrite, ammonium, phosphates, silica, total nitrogen and phosphorus, dissolved oxygen and chlorophyll) content. To assess the toxicity degree and nutrient potential of water, bioassay test conducted by growing daphnia in water samples were held. The study shows that the Don River delta water is characterized by the relatively low values of dissolved heavy metal content. Significantly higher values of heavy metals were determined in the vicinity of settlements only. Metal accumulation in bottom sediments can be associated mainly with the rate of water flow. Higher values were found in sediments of small channels with weak flow velocity and prevailing processes of the suspended matter deposition. The data on the seasonal dynamics of nutrients and spatial variability of their forms have been obtained. The maximum concentration of nitrogen, phosphorus, silicon, and other biogenic elements are

  17. Conceptual model of sedimentation in the Sacramento-San Joaquin River Delta

    Science.gov (United States)

    Schoellhamer, David H.; Wright, Scott A.; Drexler, Judith Z.

    2012-01-01

    Sedimentation in the Sacramento–San Joaquin River Delta builds the Delta landscape, creates benthic and pelagic habitat, and transports sediment-associated contaminants. Here we present a conceptual model of sedimentation that includes submodels for river supply from the watershed to the Delta, regional transport within the Delta and seaward exchange, and local sedimentation in open water and marsh habitats. The model demonstrates feedback loops that affect the Delta ecosystem. Submerged and emergent marsh vegetation act as ecosystem engineers that can create a positive feedback loop by decreasing suspended sediment, increasing water column light, which in turn enables more vegetation. Sea-level rise in open water is partially countered by a negative feedback loop that increases deposition if there is a net decrease in hydrodynamic energy. Manipulation of regional sediment transport is probably the most feasible method to control suspended sediment and thus turbidity. The conceptual model is used to identify information gaps that need to be filled to develop an accurate sediment transport model.

  18. Shallow stratigraphy of the Skagit River Delta, Washington, derived from sediment cores

    Science.gov (United States)

    Grossman, Eric E.; George, Douglas A.; Lam, Angela

    2011-01-01

    Sedimentologic analyses of 21 sediment cores, ranging from 0.4 to 9.6 m in length, reveal that the shallow geologic framework of the Skagit River Delta, western Washington, United States, has changed significantly since 1850. The cores collected from elevations of 3.94 to -2.41 m (relative to mean lower low water) along four cross-shore transects between the emergent marsh and delta front show relatively similar environmental changes across an area spanning ~75 km2. Offshore of the present North Fork Skagit River and South Fork Skagit River mouths where river discharge is focused by diked channels through the delta, the entire 5–7-km-wide tidal flats are covered with 1–2 m of cross-bedded medium-to-coarse sands. The bottoms of cores, collected in these areas are composed of mud. A sharp transition from mud to a cross-bedded sand unit indicates that the tidal flats changed abruptly from a calm environment to an energetic one. This is in stark contrast to the Martha's Bay tidal flats north of the Skagit Bay jetty that was completed in the 1940s to protect the newly constructed Swinomish Channel from flooding and sedimentation. North of the jetty, mud ranging from 1 to 2 m thick drapes a previously silt- and sand-rich tidal flat. The silty sand is a sediment facies that would be expected there where North Fork Skagit River sedimentation occurred prior to jetty emplacement. This report describes the compositional and textural properties of the sediment cores by using geophysical, photographic, x-radiography, and standard sediment grain-size and carbon-analytical methods. The findings help to characterize benthic habitat structure and sediment transport processes and the environmental changes that have occurred across the nearshore of the Skagit River Delta. The findings will be useful for quantifying changes to nearshore marine resources, including impacts resulting from diking, river-delta channelization, shoreline development, and natural variations in fluvial

  19. Impacts of urbanization on hydrology in the Yangtze River Delta, China.

    Science.gov (United States)

    Youpeng, Xu; Jintao, Xu; Jinjia, Ding; Ying, Chen; Yixing, Yin; Xingqi, Zhang

    2010-01-01

    The Yangtze River Delta is one of the most developed regions in China and the rapid development of urbanization have greatly influenced regional hydrology and water resources. Taking several typical urbanizing areas in the Yangtze River Delta as examples, this paper probes into the impacts of urbanization on hydrologic cycle and hydrological process with the support of RS, GIS and hydrological model. The research centers on the impacts of urbanization on precipitation, hydrological process, river networks, and water environment in some typical cities. The results show that: (1) Urban rain island effect is not evident when the process of urbanization is slow, while the differences of annual precipitation and flood season precipitation between urban and suburban areas increased to a certain extent in the booming stage of urbanization. (2) The annual runoff depth and the runoff coefficient increased with the development of urbanization, and the effect will be more notable when the urban areas expand to a certain size; (3) River network systems, especially low-grade rivers have been greatly destroyed in the process of urbanization, which increases the risk of flood and water degradation, so it is very important to protect natural river systems. Based on the results, some proposals of sustainable utilization and protection of water resources is also addressed.

  20. Water Rights for Wetlands in the Bear River Delta

    OpenAIRE

    2016-01-01

    This fact sheet explains the basic premise and functioning of water rights in Utah and how water rights affect wetlands, specifically those in the northern region of the state. It includes the history of Utah water rights and the basic components of prior appropriation doctrine, and gives an example of using water rights for wetlands by explaining how the Bear River Migratory Bird Refuge works with neighboring water users to secure water for its wetlands.

  1. Fingerprinting analysis and characterization of hydrocarbons in sediments of the Pearl River Delta in China

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.; Wang, Z.; Hollebone, B.; Yang, Z.; Brown, C.; Landriault, M. [Environment Canada, Ottawa, ON (Canada). Emergencies Science and Technology Section; Peng, X. [Chinese Academy of Sciences, Guangzhou (China). State Key Laboratory of Organic Geochemistry, Guangzhou Inst. of Geochemistry

    2009-07-01

    This paper reported on a study that used gas chromatography-mass spectrometry (GC-MS) and gas chromatography flame ionization detection (GC-FID) to investigate and characterize the contamination in southern China's Pearl River Delta, with particular reference to contamination from petroleum,n-alkanes, polycyclic aromatic hydrocarbons (PAHs), biomarkers and diamondoid compounds. Forensic analysis of sediments was necessary in order to decode the contamination history and evaluate the contamination level of the aquatic ecosystem. The contamination of the Pearl River Delta sediment was derived from various inputs, including petrogenic, biogenic and pyrogenic sources. However, in addition to identifying PAHs and biomarker terpanes and steranes, the detection of trace diamondoid compounds in the sediments demonstrated that the pollution in the river was derived partially from petroleum sources. Diamondoids are a class of saturated hydrocarbons that consist of three-dimensionally fused cyclohexane rings. They occur naturally in source rocks, crude oils, intermediate petroleum distillates, and finished petroleum products. They are more resistant to biodegradation than most other petroleum compounds such as n-alkanes. As such, they can play an important role in identifying and characterizing petroleum contamination in the environment. It was concluded that the petroleum contamination in the Pearl River Delta is attributed to the mixture of medium to heavy petroleum residues. 31 refs., 6 tabs., 4 figs.

  2. Holocene emergence and evolution of the McArthur River Delta, southwestern Gulf of Carpentaria, Australia

    Science.gov (United States)

    Woodroffe, C. D.; Chappell, J.

    1993-03-01

    The McArthur River drains from a semiarid, sandstone catchment into a shallow embayment behind the Sir Edward Pellew Group of islands in the southwestern Gulf of Carpentaria. It has built a broad Holocene delta, presently with two active distributaries and several abandoned, mangrove-lined, former distributaries. Augering indicates that much of the delta is underlain by shelly sands which contain distinct shell beds in their position of growth. These are interpreted as delta front deposits, and the elevation of the landwardmost beds above high tide level implies emergence of 1-2 m over the last 4000 years. This relative sea-level fall appears to have been a major cause of rapid mid-Holocene delta progradation. The eastern margin of the delta has undergone little net progradation over the last 2000 years, though there has been accretion of small mangrove-covered islands to the northwest of the delta. Distributaries have migrated across the upper deltaic plain by lateral migration, leaving nested sequences of fluvial ridges. In the lower deltaic plain, channel migration appears to have occurred mainly by avulsion; former distributaries have been infilled with fluvial sands and are now tidally dominated.

  3. The combined impact on the flooding in Vietnam's Mekong River delta of local man-made structures, sea level rise, and dams upstream in the river catchment

    Science.gov (United States)

    Le, Thi Viet Hoa; Nguyen, Huu Nhan; Wolanski, Eric; Tran, Thanh Cong; Haruyama, Shigeko

    2007-01-01

    The Mekong River delta plays an important role in the Vietnamese economy and it has been severely impacted during this century by a series of unusually large floods. In the dry season the delta is also impacted by salinity intrusion and tides. These effects have caused severe human hardship. To mitigate these impacts, a large number of engineering structures, primarily dykes and weirs, have been built in the delta in recent years and are still being built, mainly to control floods and saltwater intrusion. These control measures are still being upgraded. A GIS-linked numerical model shows that the flood levels in the delta depend on the combined impacts of high river flows in the Mekong River, storm surges, sea level rise, and the likely, future siltation of the Mekong Estuary resulting from the construction of dams in China as well as many other dams proposed throughout the remaining river catchment. The model suggests that the engineering structures in the delta increase the flow velocities in the rivers and canals, increasing bank erosion, and cause the water to be deeper in the rivers and canals. This increases flooding in the non-protected areas of the delta and increases the risk of catastrophic failure of the dykes in the protected areas. The model also predicts that a sea level rise induced by global warming will enhance flooding in the Mekong River delta in Vietnam, and that flooding may worsen in the long term as a result of estuarine siltation resulting from the construction of dams. At the scale of the Mekong River basin, a multinational water resources management plan is needed that includes the hydrological needs of the delta. At the scale of the delta, a compromise is needed between allowing some flooding necessary for agriculture and preventing catastrophic flooding to alleviate human suffering.

  4. Early growth stage of a large delta — Transformation from estuarine-platform to deltaic-progradational conditions (the northeastern Mekong River Delta, Vietnam)

    Science.gov (United States)

    Hanebuth, Till J. J.; Proske, Ulrike; Saito, Yoshiki; Nguyen, Van Lap; Ta, Thi Kim Oanh

    2012-06-01

    The initial growth stage of a river delta can be defined either as the beginning geomorphologic expansion of the river-dominated coastal lowland or as the starting basinward-directed progradation of the geological/stratigraphic delta body. Differentiating between these two perspectives is necessary for understanding the sensitive reaction of a deltaic system to dynamic changes in sea-level and sediment availability. The Holocene evolution of the northeastern part of the Mekong River delta (Southern Vietnam) offers a great chance to depict these two different definitions and relate them genetically to each other since the transition between an old abrasion platform (inner delta) and the continental-shelf basin (outer delta) is well developed in this marginal part of the delta. The early stage of delta growth taking place during transgression-related inundation between 8 cal ka BP (maximum flooding) and 5.7 (6.0-4.8) cal ka BP (sea-level highstand) was characterized by tide-and saltwater-influenced nearshore conditions allowing extensive mangrove and tidal-flat deposits to aggradate on the wide abrasion platform. With the onset of regression around 4.8 cal ka BP the depositional center shifted immediately beyond the seaward margin of this estuarine platform and thus true deltaic progradation could develop leading to rapid construction of a delta body (and, in addition, to subsidence/tilting of the inner delta zone). Directly at the transition of these two deposystems, remains of shore-related deposits indicate the sudden breakdown of the estuarine platform conditions around 4.6 cal ka BP.

  5. River-plume sedimentation and 210Pb/7Be seabed delivery on the Mississippi River delta front

    Science.gov (United States)

    Keller, Gregory; Bentley, Samuel J.; Georgiou, Ioannis Y.; Maloney, Jillian; Miner, Michael D.; Xu, Kehui

    2017-06-01

    To constrain the timing and processes of sediment delivery and submarine mass-wasting events spanning the last few decades on the Mississippi River delta front, multi-cores and gravity cores (0.5 and undulatory profiles with overall declining activity versus depth. Undulations are not associated with grain size variations, and are interpreted to represent variations in oceanic 210Pb scavenging by river-plume sediments. The 210Pb profile of one gravity core from a mudflow gully displays uniform basal excess activity over a zone of low and uniform bulk density, interpreted to be a mass-failure event that occurred 9-18 years before core collection. Spatial trends in sediment deposition (from 7Be) and accumulation (from 210Pb) indicate that proximity to the river mouth has stronger influence than local facies (mudflow gully, depositional lobe, prodelta) over the timeframe and seabed depth represented by the cores (<40 years, <3 m length). This may be explained by rapid proximal sediment deposition from river plumes coupled with infrequent tropical cyclone activity near the delta in the last 7 years (2006-2013), and by the location of most sediment failure surfaces (from mass flows indicated by parallel geophysical studies) deeper than the core-sampling depths of the present study.

  6. Transient modeling of the ground thermal conditions using satellite data in the Lena River delta, Siberia

    Science.gov (United States)

    Westermann, Sebastian; Peter, Maria; Langer, Moritz; Schwamborn, Georg; Schirrmeister, Lutz; Etzelmüller, Bernd; Boike, Julia

    2017-06-01

    Permafrost is a sensitive element of the cryosphere, but operational monitoring of the ground thermal conditions on large spatial scales is still lacking. Here, we demonstrate a remote-sensing-based scheme that is capable of estimating the transient evolution of ground temperatures and active layer thickness by means of the ground thermal model CryoGrid 2. The scheme is applied to an area of approximately 16 000 km2 in the Lena River delta (LRD) in NE Siberia for a period of 14 years. The forcing data sets at 1 km spatial and weekly temporal resolution are synthesized from satellite products and fields of meteorological variables from the ERA-Interim reanalysis. To assign spatially distributed ground thermal properties, a stratigraphic classification based on geomorphological observations and mapping is constructed, which accounts for the large-scale patterns of sediment types, ground ice and surface properties in the Lena River delta. A comparison of the model forcing to in situ measurements on Samoylov Island in the southern part of the study area yields an acceptable agreement for the purpose of ground thermal modeling, for surface temperature, snow depth, and timing of the onset and termination of the winter snow cover. The model results are compared to observations of ground temperatures and thaw depths at nine sites in the Lena River delta, suggesting that thaw depths are in most cases reproduced to within 0.1 m or less and multi-year averages of ground temperatures within 1-2 °C. Comparison of monthly average temperatures at depths of 2-3 m in five boreholes yielded an RMSE of 1.1 °C and a bias of -0.9 °C for the model results. The highest ground temperatures are calculated for grid cells close to the main river channels in the south as well as areas with sandy sediments and low organic and ice contents in the central delta, where also the largest thaw depths occur. On the other hand, the lowest temperatures are modeled for the eastern part, which is an

  7. Environmental and eelgrass response to dike removal: Nisqually River Delta (2010–14)

    Science.gov (United States)

    Takesue, Renee K.

    2016-10-03

    Restoration of tidal flows to formerly diked marshland can alter land-to-sea fluxes and patterns of accumulation of terrestrial sediment and organic matter, and these tidal flows can also affect existing nearshore habitats. Dikes were removed from 308 hectares (ha) of the Nisqually National Wildlife Refuge on the Nisqually River Delta in south Puget Sound, Washington, in fall 2009 to improve habitat for wildlife, such as juvenile salmon. Ecologically important intertidal and subtidal eelgrass (Zostera marina) beds grow on the north and west margins of the delta. The goal of this study was to understand long-term changes in eelgrass habitat and their relation to dike removal. Sediment and eelgrass properties were monitored annually in May from 2010 to 2014 at two sites on the west side of the Nisqually River Delta along McAllister Creek, a spring-fed creek near two restored tidal channels. In May 2014, the mean canopy height of eelgrass was the same as in previous years in an 8-ha bed extending to the Nisqually River Delta front, but mean canopy height was 20 percent lower in a 0.3-ha eelgrass bed closer to the restored marsh when compared to mean canopy height of eelgrass in May 2010, 6 months after dike removal was completed. Over 5 years, the amount of eelgrass leaf area per square meter (m2) in the 8-ha bed increased slightly, and surface-sediment grain size became finer. In contrast, in the 0.3-ha bed, eelgrass leaf area per m2 decreased by 45 percent, and surface sediment coarsened. Other potential stressors, including sediment pore water reduction-oxidation potential (redox) and hydrogen sulfide (H2S) concentration in the eelgrass rhizosphere, or root zone, were below levels that negatively affect eelgrass growth and therefore did not appear to be environmental stressors on plants. Eelgrass biomass partitioning, though less favorable in the 8-ha eelgrass bed compared to the 0.3-ha one, was well above the critical above-ground to below-ground biomass ratio of

  8. Magnitude of arsenic pollution in the Mekong and Red River Deltas - Cambodia and Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Michael [Swiss Federal Institute of Aquatic Science and Technology (Eawag), CH-8600 Dubendorf (Switzerland)]. E-mail: michael.berg@eawag.ch; Stengel, Caroline [Swiss Federal Institute of Aquatic Science and Technology (Eawag), CH-8600 Dubendorf (Switzerland); Trang, Pham Thi Kim [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Hanoi (Viet Nam); Hung Viet, Pham [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, Hanoi (Viet Nam); Sampson, Mickey L. [Resource Development International-Cambodia (RDIC), P.O. Box 494, Phnom Penh (Cambodia); Leng, Moniphea [Resource Development International-Cambodia (RDIC), P.O. Box 494, Phnom Penh (Cambodia); Samreth, Sopheap [Resource Development International-Cambodia (RDIC), P.O. Box 494, Phnom Penh (Cambodia); Fredericks, David [Phnom Penh (Cambodia)

    2007-01-01

    Large alluvial deltas of the Mekong River in southern Vietnam and Cambodia and the Red River in northern Vietnam have groundwaters that are exploited for drinking water by private tube-wells, which are of increasing demand since the mid-1990s. This paper presents an overview of groundwater arsenic pollution in the Mekong delta: arsenic concentrations ranged from 1-1610 {mu}g/L in Cambodia (average 217 {mu}g/L) and 1-845 {mu}g/L in southern Vietnam (average 39 {mu}g/L), respectively. It also evaluates the situation in Red River delta where groundwater arsenic concentrations vary from 1-3050 {mu}g/L (average 159 {mu}g/L). In addition to rural areas, the drinking water supply of the city of Hanoi has elevated arsenic concentrations. The sediments of 12-40 m deep cores from the Red River delta contain arsenic levels of 2-33 {mu}g/g (average 7 {mu}g/g, dry weight) and show a remarkable correlation with sediment-bound iron. In all three areas, the groundwater arsenic pollution seem to be of natural origin and caused by reductive dissolution of arsenic-bearing iron phases buried in aquifers. The population at risk of chronic arsenic poisoning is estimated to be 10 million in the Red River delta and 0.5-1 million in the Mekong delta. A subset of hair samples collected in Vietnam and Cambodia from residents drinking groundwater with arsenic levels > 50 {mu}g/L have a significantly higher arsenic content than control groups (< 50 {mu}g/L). Few cases of arsenic related health problems are recognized in the study areas compared to Bangladesh and West Bengal. This difference probably relates to arsenic contaminated tube-well water only being used substantially over the past 7 to 10 years in Vietnam and Cambodia. Because symptoms of chronic arsenic poisoning usually take more than 10 years to develop, the number of future arsenic related ailments in Cambodia and Vietnam is likely to increase. Early mitigation measures should be a high priority.

  9. Remote Sensing of Bidecadal Urbanization and its impact on Ecosystem Service in the Yangtze River Delta

    Science.gov (United States)

    Haas, Jan; Ban, Yifang

    2013-01-01

    The degree of urbanization and resulting effects on Ecosystem Services is investigated in the Yangtze River Delta in China within a 20 year time frame from 1990 to 2010. A Random forest classifier is used to classify the Landsat mosaic from 1990 and the HJ-1A/B mosaic dating from 2010. Urban Land Index (UI) and Urban Expansion Index (UX) are used to represent the intensity and rapidity of urbanization. Post-Classification Change Detection is then performed and Ecosystem Service value losses for the land-cover classes water, wetland, forest and cropland that transitioned to urban areas are calculated according to a valuation scheme adapted to the Chinese market. The results showed that Yangtze River Delta experienced significant urbanization during 1990 to 2010. Urban areas increased alongside a major decrease in cropland resulting in a substantial loss of 4.2 billion CNY in Ecosystem Services.

  10. Spatio-temporal patterns and predictions of phytoplankton assemblages in a subtropical river delta system

    DEFF Research Database (Denmark)

    Wang, Chao; Li, Xinhui; Wang, Xiangxiu;

    2016-01-01

    similarities. These groups were distinct with respect to species richness, biomass and indicators, especially for groups representing spatial dimension. The Linear Discriminant Analysis (LDA) model indicated that the spatial patterns of phytoplankton assemblages were mostly explained by water quality variables...... dominate? Are physical or chemical factors determining the above patterns in this area? We conclude that the spatial-temporal patterns of phytoplankton in the PRD are closely associated with eutrophication levels caused by anthropogenic activities. The spatial patterns are apparently dominant in this area......Spatial and seasonal sampling within a subtropical river delta system, the Pearl River Delta (China), provided data to determine seasonal phytoplankton patterns and develop prediction models. The high nutrient levels and frequent water exchanges resulted in a phytoplankton community with greatest...

  11. Characteristics Process of Land Use Changes in the Yangtze River Delta,Chian

    Institute of Scientific and Technical Information of China (English)

    PULIJIE; YANGGUISHAN; 等

    2001-01-01

    As one of the developing countries China has an arable land per capita far below the world's average level.With a high-density population an the quick development of economy and urbaniztion,the Yangtze River Delta shows the typical characteristics of land use in developed regions of China,which are:high land reclamation rate and low arable land per capita;intensive land use and high output value;and rapid increasing of construction land area and fast diminishing of arable land.The analysis indicates that the process of the arable land changes in the Yangtze River Delta could be divided into four different change stages over the past 50 years.

  12. Causes of Wetland Degradation and Ecological Restoration in the Yellow River Delta Region

    Institute of Scientific and Technical Information of China (English)

    Zhang Jian-feng; Sun Qi-xiang

    2005-01-01

    Yellow River delta (YRD) is one of the biggest deltas that there is a large area of wetland in the world. Thanks to soil(sands) sediment carried by the Yellow River, there was averagely the newly formed land 21.3 km2in YRD. During the development of petroleum industry and urban expansion, wetlands were degraded due to population growth, irrational land use, in addition to adverse natural eco-environment such as lower precipitation, higher soil evaporation and soil salinazation. The major ecological measures to restore degraded wetland concerned with ensuring water supply, especially establishing perfect irrigation works; protecting virgin plant communities and assisting them to regenerate by the way of site preparation, improving living surroundings; introducing salt-tolerant plants to increase vegetation species and plant coverage, thereby enhancing the capability of wetland to combat contamination and pollution through plant remediation, uptake, absorption, etc. Finally making a comprehensive land use plan,accordingly removing deleterious facilities.

  13. Dynamic analysis of evapotranspiration based on remote sensing in Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    PANZhiqiang; LIUGaohuan; ZHOUChenghu

    2003-01-01

    Evapotranspiration (ET) is an important parameter for water resource management. Compared to the traditional ET computation and measurement methods, the ET computation method based on remote sensing has the advantages of quickness, precision, raster mapping and regional scale. SEBAL, an ET computation model using remote sensing method is based on the surface energy balance equation which is a function of net radiance flux, soil heat flux, sensible heat flux and latent heat flux. The former three fluxes can be computed through the parameters retrieved from remote sensing image, then the latent heat flux can be obtained to provide energy for ET. Finally we can obtain the daily ET. In this study SEBAL was applied to compute ET in the Yellow River Delta of China where water resource faces a rigorous situation. Three Landsat TM images and meteorology data of 1999 were used for ET computation, and spatial and temporal change patterns of ET in the Yellow River Delta were analysed.

  14. beta (+)-Thalassaemia in the Po river delta region (northern Italy): genotype and beta globin synthesis.

    Science.gov (United States)

    Del Senno, L; Pirastu, M; Barbieri, R; Bernardi, F; Buzzoni, D; Marchetti, G; Perrotta, C; Vullo, C; Kan, Y W; Conconi, F

    1985-01-01

    Six beta(+)-thalassaemic patients from the Po river delta region have been studied. Using synthetic oligonucleotides as specific hybridisation probes, the beta(+) IVS I mutation (G----A at position 108) was demonstrated. This lesion and the enzyme polymorphism pattern in the subjects examined are the same as have been described for other Mediterranean beta(+)-thalassaemias. Antenatal diagnosis through DNA analysis of beta(+)-thalassaemia is therefore possible. The production of beta globin in a beta(+), homozygote and in a beta (+), beta(0) 39 (nonsense mutation at codon 39) double heterozygote is approximately 20% and 10% respectively of total non-alpha globin synthesis. Despite some overlapping of the results, similar beta globin synthesis levels have been obtained in 43 beta(+)-thalassaemia patients. This suggests that in the Po river delta region the most common thalassaemic genes are beta(0) 39 and beta(+) IVS I. Images PMID:2580095

  15. Spectacled Eiders (Somateria fischeri) capture and resight records, Kashunuk River, Yukon-Kuskokwim Delta, Alaska, 1995-2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Data set containing capture and band resight data associated with marked Spectacled Eiders, observed near the Kashunuk River, within the Yukon-Kuskokwim Delta, Alaska.

  16. 2008 USGS/NPS/NASA Experimental Advanced Airborne Research Lidar (EAARL): Pearl River Delta, LA and MS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A bare earth elevation map (also known as a Digital Elevation Model or DEM) of the Pearl River Delta in Louisiana and Mississippi was produced from remotely sensed,...

  17. 78 FR 39314 - Notice of Availability of the Decision Record for the Delta River Special Recreation Management...

    Science.gov (United States)

    2013-07-01

    ... Information Relay Service (FIRS) at 1-800-877-8339 to contact the above individual during normal business... environment and the outstandingly remarkable values of the Delta River SRMA. It provides a balanced management...

  18. Northern Manitoba, northern Saskatchewan, and the Saskatchewan River Delta: Waterfowl production survey: July 5-23, 1983

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the Waterfowl Production and Habitat Survey for northern Manitoba, northern Saskatchewan, and the Saskatchewan River Delta during 1983. The...

  19. Potential plant species distribution in the Yellow River Delta under the influence of groundwater level and soil salinity

    NARCIS (Netherlands)

    Fan Xiaomei,; Pedroli, B.; Liu Gaohuan,; Liu Hongguang,; Song Chuangye,; Shu Longcang,

    2011-01-01

    This article describes a multidisciplinary approach to assessing potential vegetation types. The relation between vegetation distribution as derived from field survey and habitat characteristics in the Yellow River Delta (YRD) was analyzed using detrended canonical correspondence analysis (DCCA). Th

  20. Potential plant species distribution in the Yellow River Delta under the influence of groundwater level and soil salinity

    NARCIS (Netherlands)

    Fan Xiaomei,; Pedroli, B.; Liu Gaohuan,; Liu Hongguang,; Song Chuangye,; Shu Longcang,

    2011-01-01

    This article describes a multidisciplinary approach to assessing potential vegetation types. The relation between vegetation distribution as derived from field survey and habitat characteristics in the Yellow River Delta (YRD) was analyzed using detrended canonical correspondence analysis (DCCA).

  1. 2008 USGS/NPS/NASA Experimental Advanced Airborne Research Lidar (EAARL): Pearl River Delta, LA and MS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A bare earth elevation map (also known as a Digital Elevation Model or DEM) of the Pearl River Delta in Louisiana and Mississippi was produced from remotely sensed,...

  2. [Source apportionment of dioxin-like polychlorinated biphenyls in soil of the modern Yellow River Delta].

    Science.gov (United States)

    Liu, Jing; Cui, Zhao-jie; Fan, Guo-lan; Xu, Hong-yu

    2007-12-01

    The concentrations of 12 dioxin-like polychlorinated biphenyls (PCBs) in twenty two soil samples collected from modern Yellow River Delta were determined by dual capillary GC-ECD associated with GC-MS. Principle component analysis (PCA) was applied in analysing the dioxin-like PCBs data to obtain types, sources, percentages of source contribution and the congener composition of PCBs in the Delta on the congener level. The results indicated that four types of PCBs contamination sources affecting the PCBs distribution pattern were apportioned in the Delta. The first source was water runoff (non-point source), which was from the industrial production and use by the enterprises along the Yellow River, and it contributed 49.6% of the total contamination burden in the Delta, its dioxin-like PCBs profile was similar to native PCBs and Aroclorl221; the second and third types of PCBs sources were point sources, whose percentages of contribution were 15.0% and 10.1% respectively, the composition of the second source was similar to that of Aroclor1221 and Aroclor1242, the composition of the third source was similar to that of Aroclor1260; the fourth source is believed to be non-point source which was from the atmospheric dry and wet precipitation, it contributed 8.4%, its profile have similarity composition of the integration of Aroclor1242, Aroclor1248 and Aroclor1260.

  3. Emergy Synthesis and Regional Sustainability Assessment: Case Study of Pan-Pearl River Delta in China

    OpenAIRE

    2014-01-01

    In this paper, emergy analysis is used in association with the ternary diagrams and geographic information system (GIS) tools to improve the evaluation of sustainability for the Pan-Pearl River Delta (PPRD) region. Emergy accounting of PPRD is estimated, and various emergy-based indicators are reported. Ternary diagrams are drawn to provide a graphical representation of the emergy accounting data. Finally, the GIS tools are employed to assist in the emergy-based spatial analysis, and emergy d...

  4. Validation of a Parcel-Based Reduced-Complexity Model for River Delta Formation (Invited)

    Science.gov (United States)

    Liang, M.; Geleynse, N.; Passalacqua, P.; Edmonds, D. A.; Kim, W.; Voller, V. R.; Paola, C.

    2013-12-01

    Reduced-Complexity Models (RCMs) take an intuitive yet quantitative approach to represent processes with the goal of getting maximum return in emergent system-scale behavior with minimum investment in computational complexity. This approach is in contrast to reductionist models that aim at rigorously solving the governing equations of fluid flow and sediment transport. RCMs have had encouraging successes in modeling a variety of geomorphic systems, such as braided rivers, alluvial fans, and river deltas. Despite the fact that these models are not intended to resolve detailed flow structures, questions remain on how to interpret and validate the output of RCMs beyond qualitative behavior-based descriptions. Here we present a validation of the newly developed RCM for river delta formation with channel dynamics (Liang, 2013). The model uses a parcel-based 'weighted-random-walk' method that resolves the formation of river deltas at the scale of channel dynamics (e.g., avulsions and bifurcations). The main focus of this validation work is the flow routing model component. A set of synthetic test cases were designed to compare hydrodynamic results from the RCM and Delft3D, including flow in a straight channel, around a bump, and flow partitioning at a single bifurcation. Output results, such as water surface slope and flow field, are also compared to field observations collected at Wax Lake Delta. Additionally, we investigate channel avulsion cycles and flow path selection in an alluvial fan with differential styles of subsidence and compare model results to laboratory experiments, as a preliminary effort in pairing up numerical and experimental models to understand channel organization at process scale. Strengths and weaknesses of the RCM are discussed and potential candidates for model application identified.

  5. beta (+)-Thalassaemia in the Po river delta region (northern Italy): genotype and beta globin synthesis.

    OpenAIRE

    del Senno, L; Pirastu, M; Barbieri, R.; De Bernardi, F.; Buzzoni, D; Marchetti, G.; Perrotta, C; Vullo, C; Kan, Y W; Conconi, F

    1985-01-01

    Six beta(+)-thalassaemic patients from the Po river delta region have been studied. Using synthetic oligonucleotides as specific hybridisation probes, the beta(+) IVS I mutation (G----A at position 108) was demonstrated. This lesion and the enzyme polymorphism pattern in the subjects examined are the same as have been described for other Mediterranean beta(+)-thalassaemias. Antenatal diagnosis through DNA analysis of beta(+)-thalassaemia is therefore possible. The production of beta globin in...

  6. Appraising sustainable flood risk management in the Pearl River Delta's coastal megacities: A case study of Hong Kong, China

    OpenAIRE

    Chan, F. K. S.; Adekola, O. A.; Mitchell, G.; McDonald, A. T.

    2013-01-01

    The Pearl River Delta (PRD) region has experienced rapid economic and population growth in the last three decades. The delta includes coastal megacities, such as Hong Kong. These low-lying urbanised coastal regions in the PRD are vulnerable to flood risks from unpredictable climatic conditions. These can result in increasing storm surges, rising sea level and intensified rainstorms causing coastal and inland flooding, all of which impact the delta. This paper has taken the coastal megacity of...

  7. Rice market integration in the Mekong river delta : the successful liberalisation of the domestic food market in Vietnam

    NARCIS (Netherlands)

    Hai, Luu Thanh Duc; Lutz, Clemens; Praagman, Cornelis

    2004-01-01

    This article analyses the spatial price differences in the rice market of the Mekong River Delta to assess the impact of the liberalisation policies on its functioning. The results of these policies carried out during the last two decades are impressive. The rice market system in the Delta is

  8. Modern Pearl River Delta and Permian Huainan coalfield, China: A comparative sedimentary facies study

    Science.gov (United States)

    Suping, P.; Flores, R.M.

    1996-01-01

    Sedimentary facies types of the Pleistocene deposits of the Modern Pearl River Delta in Guangdong Province, China and Permian Member D deposits in Huainan coalfield in Anhui Province are exemplified by depositional facies of anastomosing fluvial systems. In both study areas, sand/sandstone and mud/mudstone-dominated facies types formed in diverging and converging, coeval fluvial channels laterally juxtaposed with floodplains containing ponds, lakes, and topogenous mires. The mires accumulated thin to thick peat/coal deposits that vary in vertical and lateral distribution between the two study areas. This difference is probably due to attendant sedimentary processes that affected the floodplain environments. The ancestral floodplains of the Modern Pearl River Delta were reworked by combined fluvial and tidal and estuarine processes. In contrast, the floodplains of the Permian Member D were mainly influenced by freshwater fluvial processes. In addition, the thick, laterally extensive coal zones of the Permian Member D may have formed in topogenous mires that developed on abandoned courses of anastomosing fluvial systems. This is typified by Seam 13-1, which is a blanket-like body that thickens to as much as 8 in but also splits into thinner beds. This seam overlies deposits of diverging and converging, coeval fluvial channels of the Sandstone D, and associated overbank-floodplain deposits. The limited areal extent of lenticular Pleistocene peat deposits of the Modern Pearl River Delta is due to their primary accumulation in topogenous mires in the central floodplains that were restricted by contemporaneous anastomosing channels.

  9. DEVELOPMENT ELECTRONIC MAPS OF ECOLOGICAL STATUS OF WATER OBJECTS OF THE VOLGA RIVER DELTA

    Directory of Open Access Journals (Sweden)

    Z. N. Isenalieva

    2016-01-01

    Full Text Available Abstract. Aim. The aim of this work was the comprehensive study of the ecological state of water objects of the Volga River delta. Methods. The following methods were used: field (collection, observation, organoleptic, uniform chemical analysis techniques are based on colorimetric, settlement, photometric, spectrometric measurement methods. Results. On the basis of results of researches for 2010-2014 performed a comparative analysis of the dynamics of the content of hydro-chemical indicators of environmental quality in waters of the Volga River delta and the residential areas of the background. Applying an integrated approach to the study of biological indicators of water quality. Created digitized map of the quality of aquatic ecosystems of the Volga River delta. Displaying modern ecological condition of watercourses investigated, determined the degree of contamination, the overall trophic and saprobic. Main conclusions. The work has identified adverse environmental situation in water objects of the Astrakhan and the surrounding areas. Average annual concentrations of toxicological substances water objects in the background zone 10 times less than in the water objects of settlements. As a result of work on the basis of ArcGis 10.2.2 created information environment "Eco-monitor", which is a systematic set of information, and quantitatively characterizing the ecological status of water objects. Created on the basis of ArcGis 10.2.2 information environment monitoring system of waterways allows for a temporary and spatial analysis, to assess the quality of different streams in the control sections.

  10. Sediment suspension and the dynamic mechanism during storms in the Yellow River Delta.

    Science.gov (United States)

    Bian, Shuhua; Hu, Zjian; Liu, Jianqiang; Zhu, Zichen

    2016-12-01

    The suspension and hydrodynamic characteristics of the Yellow River Delta during storms were analyzed based on suspended samples obtained using automatic samplers during a storm event in the Yellow River Delta. Synchronous data for winds, waves, and tides were also collected from a nearby station. The results show that under wind speeds of 5-15 m/s and wave heights of 50-150 cm, the suspended content reached 5.7-49.6 kg/m(3), which is 10-100 times higher than that under normal weather conditions. The medium diameter of suspended particles was 1.2-2.1 μm (8.9-9.7 Φ), which was approximately 1-2 Φ finer than that under normal weather conditions. During the early stages of the measurements, the sea level had risen by 50 cm owing to the storm, which was in addition to the tidal sea level change. We suggest that during the storms, the waves strengthened and the storm-induced sea level change, which was combined with tidal currents moving in the same direction, produced high-speed currents. This overcame the cohesive forces among the fine sediment particles and suspended a large amount of sediment. As a result, the suspended content increased markedly and the suspended particle size became finer. This explains the intense siltation and erosion of the Yellow River Delta during storms.

  11. Potential Activity of Subglacial Microbiota Transported to Anoxic River Delta Sediments.

    Science.gov (United States)

    Cameron, Karen A; Stibal, Marek; Olsen, Nikoline S; Mikkelsen, Andreas B; Elberling, Bo; Jacobsen, Carsten S

    2017-07-01

    The Watson River drains a portion of the SW Greenland ice sheet, transporting microbial communities from subglacial environments to a delta at the head of Søndre Strømfjord. This study investigates the potential activity and community shifts of glacial microbiota deposited and buried under layers of sediments within the river delta. A long-term (12-month) incubation experiment was established using Watson River delta sediment under anaerobic conditions, with and without CO2/H2 enrichment. Within CO2/H2-amended incubations, sulphate depletion and a shift in the microbial community to a 52% predominance of Desulfosporosinus meridiei by day 371 provides evidence for sulphate reduction. We found evidence of methanogenesis in CO2/H2-amended incubations within the first 5 months, with production rates of ~4 pmol g(-1) d(-1), which was likely performed by methanogenic Methanomicrobiales- and Methanosarcinales-related organisms. Later, a reduction in methane was observed to be paired with the depletion of sulphate, and we hypothesise that sulphate reduction out competed hydrogenotrophic methanogenesis. The structure and diversity of the original CO2/H2-amended incubation communities changed dramatically with a major shift in predominant community members and a decline in diversity and cell abundance. These results highlight the need for further investigations into the fate of subglacial microbiota within downstream environments.

  12. Contamination profiles of perfluoroalkyl substances in five typical rivers of the Pearl River Delta region, South China.

    Science.gov (United States)

    Pan, Chang-Gui; Ying, Guang-Guo; Liu, You-Sheng; Zhang, Qian-Qian; Chen, Zhi-Feng; Peng, Feng-Jiao; Huang, Guo-Yong

    2014-11-01

    A survey on contamination profiles of eighteen perfluoroalkyl substances (PFASs) was performed via high performance liquid chromatography-tandem mass spectrometry for surface water and sediments from five typical rivers of the Pearl River Delta region, South China in summer and winter in 2012. The total concentrations of the PFASs in the water phase of the five rivers ranged from 0.14 to 346.72 ng L(-1). The PFAS concentrations in the water phase were correlated positively to some selected water quality parameters such as chemical oxygen demand (COD) (0.7913) and conductivity (0.5642). The monitoring results for the water samples showed significant seasonal variations, while those for the sediment samples showed no obvious seasonal variations. Among the selected 18 PFASs, perfluorooctane sulfonic acid (PFOS) was the dominant PFAS compound both in water and sediment for two seasons with its maximum concentration of 320.5 ng L(-1) in water and 11.4 ng g(-1) dry weight (dw) in sediment, followed by perfluorooctanoic acid (PFOA) with its maximum concentration of 26.48 ng L(-1) in water and 0.99 ng g(-1) dw in sediment. PFOS and PFOA were found at relatively higher concentrations in the Shima River and Danshui River than in the other three rivers (Xizhijiang River, Dongjiang River and Shahe River). The principal component analysis for the PFASs concentrations in water and sediment separated the sampling sites into two groups: rural and agricultural area, and urban and industrial area, suggesting the PFASs in the riverine environment were mainly originated from industrial and urban activities in the region.

  13. Holocene evolution of the Song Hong (Red River) delta system, northern Vietnam

    Science.gov (United States)

    Tanabe, Susumu; Saito, Yoshiki; Lan Vu, Quang; Hanebuth, Till J. J.; Lan Ngo, Quang; Kitamura, Akihisa

    2006-05-01

    The Song Hong (Red River) delta, located on the western coast of the Gulf of Bac Bo (Tonkin) in the South China Sea, formed as a result of the Song Hong sediment discharge throughout the Holocene. The river's sedimentary basin upstream from the delta plain is not large. The delta plain comprises emerged tidal/mangrove flats formed during the sea-level highstand at + 2-3 m (6-4 cal. kyr BP) and a beach-ridge strandplain, with straight-to-lobate beach ridges, on the landward and seaward sides of the delta plain, respectively. The delta affords us the opportunity to examine river-mouth morphodynamics comprehensively in relation to sediment discharge and sea-level changes. In this paper, we describe the Holocene evolution of the Song Hong delta system and the river-mouth morphodynamics on the basis of seven sediment cores, each 30-70 m long, taken from the delta plain during 1999-2001 and 101 radiocarbon dates obtained from the core sediments. Sediments from the seven cores, consisting of incised-valley fills since the last glacial maximum, can be divided, in ascending order, into fluvial sediments composed of gravelly sand and mottled clay, tide-influenced estuarine sediments containing shell and wood fragments, and deltaic sediments composed of tide-influenced sand and mud deposits, in which the contents of sand and wood fragments increase upward. By applying sequence stratigraphic concepts, a transgressive surface can be identified at the gravelly sand-mottled clay boundary, and the maximum flooding surface can be identified at the estuarine-deltaic sediments boundary. The lowstand systems tract, transgressive systems tract, and highstand systems tract record ˜15, 15-9, and 9-0 cal. kyr BP, respectively. During the past 9 kyr, the majority of the sediment discharged by the Song Hong accumulated in the incised valley and enhanced progradation at the river mouth. The river mouth prograded from the bay head toward the gulf, and its morphology changed from funnel

  14. Bacterial production and microbial food web structure in a large arctic river and the coastal Arctic Ocean

    Science.gov (United States)

    Vallières, Catherine; Retamal, Leira; Ramlal, Patricia; Osburn, Christopher L.; Vincent, Warwick F.

    2008-12-01

    Globally significant quantities of organic carbon are stored in northern permafrost soils, but little is known about how this carbon is processed by microbial communities once it enters rivers and is transported to the coastal Arctic Ocean. As part of the Arctic River-Delta Experiment (ARDEX), we measured environmental and microbiological variables along a 300 km transect in the Mackenzie River and coastal Beaufort Sea, in July-August 2004. Surface bacterial concentrations averaged 6.7 × 10 5 cells mL - 1 with no significant differences between sampling zones. Picocyanobacteria were abundant in the river, and mostly observed as cell colonies. Their concentrations in the surface waters decreased across the salinity gradient, dropping from 51,000 (river) to 30 (sea) cells mL - 1 . There were accompanying shifts in protist community structure, from diatoms, cryptophytes, heterotrophic protists and chrysophytes in the river, to dinoflagellates, prymnesiophytes, chrysophytes, prasinophytes, diatoms and heterotrophic protists in the Beaufort Sea. Size-fractionated bacterial production, as measured by 3H-leucine uptake, varied from 76 to 416 ng C L - 1 h - 1 . The contribution of particle-attached bacteria (> 3 µm fraction) to total bacterial production decreased from > 90% at the Mackenzie River stations to importance of this particle-based fraction was inversely correlated with salinity and positively correlated with particulate organic carbon concentrations. Glucose enrichment experiments indicated that bacterial metabolism was carbon limited in the Mackenzie River but not in the coastal ocean. Prior exposure of water samples to full sunlight increased the biolability of dissolved organic carbon (DOC) in the Mackenzie River but decreased it in the Beaufort Sea. Estimated depth-integrated bacterial respiration rates in the Mackenzie River were higher than depth-integrated primary production rates, while at the marine stations bacterial respiration rates were near or

  15. Comparative study on foreign trade development patterns of the Yangtze River Delta and the Pearl River Delta%长三角与珠三角对外贸易发展模式的比较研究

    Institute of Scientific and Technical Information of China (English)

    朱诗娥; 杨汝岱

    2009-01-01

    Based on a massive collection of data,this paper tries to make a detailed comparison between the foreign trade development patterns of two export-oriented regional economies:the Yangtze River Delta and the Pearl River Delta.It is shown that both of the deltas have made spectacular progress in foreign trade development.However,the Yangtze River Delta is catching up with the Pearl River Delta,and China's foreign trade development pattern has changed in recent years from a Pearl River Delta-dominated foreign trade environment to a situation in which the Pearl River Delta and the Yangtze River Delta together dominate China's foreign trade.The primary difierence in the foreign trade development patterns of these two deltas is that foreign trade in the Pearl River Delta relies more on processing trade,while that in the Yangtze River Delta is more government-oriented with special political zones playing a significant role in its foreign trade.%利用相关数据,对长江三角洲经济区和珠江三角洲经济区的对外贸易发展模式进行详尽比较分析.结果显示:两个经济区在对外贸易方面都取得了巨大的成就.然而长二三角作为后发者,正在追赶珠三角,并且中国的外贸发展正在从以珠三角的外贸模式为主转变成两个经济区共同主宰的局面.两个经济区外贸模式的主要区别是:珠三角经济区以加工贸易为主;长三角经济区以政府导向为主,其中政策支持至关重要.

  16. Transformations of Urbanising Delta Landscape. An Historic Examination of Dealing with the Impacts of Climate Change for the Kaoping River Delta in Taiwan

    Directory of Open Access Journals (Sweden)

    Chen Kun Chung

    2014-10-01

    Full Text Available This dissertation argues that the floods following extreme precipitation result not
only from very heavy rainfall but also from the significant impact of human activities on natural water systems. While most literature emphasises that the increasing magnitude of storm rainfall extends beyond the original protection standards of hydrologic facilities in highly populated delta cities. Based on the knowledge of urban morphology, this study analyses how human systems have affected the transformation of natural water processes in the Kaoping River Delta. The relationship between human environments and natural landscape is illustrated via a 3-layer analytical framework which consists of a natural landscape layer, an infrastructure layer and an occupation layer. This layer-based approach views landscapes as a whole system in which each element interacts with the others. In order to transcend the limitations of traditional urban morphology and the overlay-mapping method, this research initiates an analysis framework with the delta scale from a deductive perspective. Furthermore,
it argues that the significant progress of infrastructure technology is the crucial factor to dominate the transformation of modern urban pattern. This influence could be identified by the analytic process of the 3-layer approach from the perspective of the delta or regional scale. This new starting point of a theoretical framework for analysing urban forms has been proved in the Kaoping Delta case. Furthermore, it could be a new and valid theoretical background to extend the knowledge of urban morphology.The formal transformation of the Kaoping Delta is divided into four main periods, which reveals human activities have affected the operation of natural systems since a century ago. From a delta scale perspective, those effects interacting between different layers can be identified in six different topographies (in italics of the whole river catchment area.A. The dike

  17. Methane and nitrous oxide concentration and emission flux of Yangtze Delta plain river net

    Institute of Scientific and Technical Information of China (English)

    WANG DongQi; CHEN ZhenLou; SUN WeiWei; HU BeiBei; XU ShiYuan

    2009-01-01

    Methane (CH4) and nitrous oxide (N2O) saturation concentration and gas-water interface emission flux in surface water of the Yangtze Delta plain river net were investigated in summer at representative sites including the upper reaches of the Huangpu River and the rivers in the Chongming Island. The results show that the CH4 concentration in river water ranged from 0.30±0.03 to 6.66±0.14 μmoI.L-1, and N2O concentration ranged from 13.8±2.33 to 435±116 nmol.L-1. River surface water had a very high satura-tion level of CH4 (from 468±49.0% to 11560±235%) and that of N2O (from 175±29.5% to 4914±1304%).Dissolved oxygen (DO) was the primary factor controlling the CH4 concentration in water. N2O concen-tration had significant negative correlation with salinity and a significant positive correlation with ni-trate (NO3-), nitrite (NO2-), chemical oxygen demand (CODcr) concentration and pH of river water. CH4 and N2O of river water were brought about mainly by methanogenesis and denitrification in river bot-tom sediment that diffused through sediment-water interface into the water body and then into at-mosphere through the gas-water interface. The emission flux of CH4 and N2O at river gas-water inter-face reached 778±59.8 and 236±03.6 μmol.m-2.h-1, respectively in summer. The river net was a potential source of atmospheric CH4 and N2O because of eutrophication of the water body.

  18. Methane and nitrous oxide concentration and emission flux of Yangtze Delta plain river net

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Methane (CH4) and nitrous oxide (N2O) saturation concentration and gas-water interface emission flux in surface water of the Yangtze Delta plain river net were investigated in summer at representative sites including the upper reaches of the Huangpu River and the rivers in the Chongming Island. The results show that the CH4 concentration in river water ranged from 0.30±0.03 to 6.66±0.14 μmol.L-1, and N2O concentration ranged from 13.8±2.33 to 435±116 nmol.L-1. River surface water had a very high satura- tion level of CH4 (from 468±49.0% to 11560±235%) and that of N2O (from 175±29.5% to 4914±1304%). Dissolved oxygen (DO) was the primary factor controlling the CH4 concentration in water. N2O concentration had significant negative correlation with salinity and a significant positive correlation with nitrate (NO3-), nitrite (NO2-), chemical oxygen demand (CODcr) concentration and pH of river water. CH4 and N2O of river water were brought about mainly by methanogenesis and denitrification in river bottom sediment that diffused through sediment-water interface into the water body and then into atmosphere through the gas-water interface. The emission flux of CH4 and N2O at river gas-water interface reached 778±59.8 and 236±63.6 μmol.m-2.h-1, respectively in summer. The river net was a potential source of atmospheric CH4 and N2O because of eutrophication of the water body.

  19. Response of reed community to the environment gradient water depth in the Yellow River Delta, China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We investigated and monitored a reed community in the fields.Data on the bio-ecologieal characteristics and β-diversity of reed communities in different environmental gradients (mainly based on water depth) of the Yellow River Delta were collected through multianalysis,extremum analysis and β-diversity index analysis.In accordance with the square sum of deviations (Ward)cluster analysis,10 sampling plots were divided into six types with the dominant plants in different plots varying according to the change in environmental gradients.The dominant plants in these plots varied from aquatic plants to xerophytes and salt tolerant plants as water depth decreased.The average height and diameter of the reeds at breast level were significantly correlated with the average water depth.The fitness curves of average density and coverage with average water depth were nonlinear.When the average water depth was 0.3 m,the average density and coverage of reeds reached the apex value,while the height and diameter of the reeds at breast level increased with the water depth.There were obvious changes to the environmental gradient in the Yellow River Delta.The transitional communities were also found to exist in the Yellow River Delta by β-diversity analysis.Vicarious species appeared with the change in water depth.The occurrence of substitute species is determined by the function of common species between adjacent belts.The different functions of common species led to differences in community structure and function and differences in dominant plants.The result reflects the variations of species present in different habitats and directly reflects environmental heterogeneity.The values of//-diversity indices of adjacent plots were higher than those of nonadjacent plots.There are transition zones between the xerophytes and aquatic plants in the Yellow River Delta.In an aquatic environment,the similarity of reed community is higher than that of xeromorphic plants.The β-diversity index

  20. Paleo-environmental evolution based on high-resolution phytolith since 26 ka B. P. in Huanghe River Delta

    Institute of Scientific and Technical Information of China (English)

    LI Ping; DU Jun; DU Na; GAO Wei

    2016-01-01

    The Huanghe River Delta is one of the world's large rivers, the Huanghe River Delta paleoenvironmental evolution in the Huanghe River has been a hot issue since the Last Glacial. Based on the core time series established by combining AMS14C dating of Core DYZK1 sediments in submerged of Huanghe River Delta and acoustic sequence on sub-bottom profile, phytolith analyses are carried out on 96 sediment samples. The grain size parameters, magnetic susceptibility are combined with the vertical changes of biostratum to reconstruct the paleo-sedimentary and climatic conditions in the Huanghe River Delta. The study results show that there is a significant vertical change law in the index parameters, and that sedimentary environment of Huanghe River Delta experienced an evolutionary process of fluvial facies-sealand transition facies-tidal flat facies-neritic facies-delta facies since 26.0 ka B. P.. The phytolith analyses results are as following. Firstly, The phytoliths are divided into lanceolate, smooth-elongated, spiny-elongated, rondel, long rectangular, bulliform and other types. In different sedimental environment, the phytolith content changes regularly, indicating that the phytolith assembles in the same sedimentary environment has a certain degree of stability. Secondly, The lanceolate, smooth-elongated and spiny-elongated categories of phytoliths have greater contents in the tidal flat facies and delta deposition, while have a smaller contents in the neritic facies and fluvial facies environment. Thirdly, Through comparative analysis of variation coefficient, the content of major phytolith categories in the sediment has a greater change amplitude in the sealand transition facies and fluvial facies deposition, while being more stable in the tidalflat facies and delta facies deposition.

  1. Analysis of the Sediment Hydrograph of the alluvial deltas in the Apalachicola River, Florida

    Science.gov (United States)

    Daranpob, A.; Hagen, S.; Passeri, D.; Smar, D. E.

    2011-12-01

    Channel and alluvial characteristics in lowlands are the products of boundary conditions and driving forces. The boundary conditions normally include materials and land cover types, such as soil type and vegetation cover. General driving forces include discharge rate, sediment loadings, tides and waves. Deltas built up of river-transported sediment occur in depositional zones of the river mouth in flat terrains and slow currents. Total sediment load depends on two major abilities of the river, the river shear stress and capacity. The shear stress determines transport of a given sediment grain size, normally expressed as tractive force. The river capacity determines the total load or quantity of total sediments transported across a section of the river, generally expressed as the sediment loading rate. The shear stress and sediment loading rate are relatively easy to measure in the headwater and transfer zones where streams form a v-shape valley and the river begins to form defined banks compared to the deposition zone where rivers broaden across lower elevation landscapes creating alluvial forms such as deltas. Determinations of deposition and re-suspension of sediment in fluvial systems are complicated due to exerting tidal, wind, and wave forces. Cyclic forces of tides and waves repeatedly change the sediment transport and deposition rate spatially and temporally in alluvial fans. However, the influence decreases with water depth. Understanding the transport, deposition, and re-suspension of sediments in the fluvial zone would provide a better understanding of the morphology of landscape in lowland estuaries such as the Apalachicola Bay and its estuary systems. The Apalachicola River system is located in the Florida Panhandle. Shelf sedimentation process is not a strong influence in this region because it is protected by barrier islands from direct ocean forces of the Gulf of Mexico. This research explores the characteristic of suspended sediment loadings in

  2. Wetland loss due to land use change in the Lower Paraná River Delta, Argentina.

    Science.gov (United States)

    Sica, Y V; Quintana, R D; Radeloff, V C; Gavier-Pizarro, G I

    2016-10-15

    Wetland loss is a global concern because wetlands are highly diverse ecosystems that provide important goods and services, thus threatening both biodiversity and human well-being. The Paraná River Delta is one of the largest and most important wetland ecosystems of South America, undergoing expanding cattle and forestry activities with widespread water control practices. To understand the patterns and drivers of land cover change in the Lower Paraná River Delta, we quantified land cover changes and modeled associated factors. We developed land cover maps using Landsat images from 1999 and 2013 and identified main land cover changes. We quantified the influence of different socioeconomic (distance to roads, population centers and human activity centers), land management (area within polders, cattle density and years since last fire), biophysical variables (landscape unit, elevation, soil productivity, distance to rivers) and variables related to extreme system dynamics (flooding and fires) on freshwater marsh conversion with Boosted Regression Trees. We found that one third of the freshwater marshes of the Lower Delta (163,000ha) were replaced by pastures (70%) and forestry (18%) in only 14years. Ranching practices (represented by cattle density, area within polders and distance to roads) were the most important factors responsible for freshwater marsh conversion to pasture. These rapid and widespread losses of freshwater marshes have potentially large negative consequences for biodiversity and ecosystem services. A strategy for sustainable wetland management will benefit from careful analysis of dominant land uses and related management practices, to develop an urgently needed land use policy for the Lower Delta.

  3. Sea-Floor Mapping and Benthic Habitat GIS for the Elwha River Delta Nearshore, Washington

    Science.gov (United States)

    Cochrane, Guy R.; Warrick, Jonathan A.; Sagy, Yael; Finlayson, David; Harney, Jodi

    2008-01-01

    From March 1531, 2005, more than 252 km (19.5 km2) of seafloor offshore of the Elwha River Delta in the central Strait of Juan de Fuca was mapped by the USGS Coastal and Marine Geology Program. The purpose of this nearshore mapping was to (1) obtain high resolution bathymetry and acoustic reflectance properties of the seabed, (2) examine and record geologic characteristics of the seafloor, and (3) construct maps of sea-floor geomorphology and habitat. Substrate distribution was characterized with video-supervised statistical classification of the sonar data. Substrate of the survey was dominated by mixed sand-gravel and sand. Numerous boulder reefs were observed west of the river mouth within Freshwater Bay, whereas the sea-floor immediately adjacent to the river mouth was dominated by sand.

  4. Profile and behavior of antiviral drugs in aquatic environments of the Pearl River Delta, China.

    Science.gov (United States)

    Peng, Xianzhi; Wang, Chunwei; Zhang, Kun; Wang, Zhifang; Huang, Qiuxin; Yu, Yiyi; Ou, Weihui

    2014-01-01

    Occurrence and behavior of six antiviral pharmaceuticals (acyclovir, ganciclovir, oseltamivir, ribavirin, stavudine and zidovudine) and one active metabolite oseltamivir carboxylate were investigated in wastewater, landfill leachate, river water, reservoir and well water in the vicinity of municipal landfills in the Pearl River Delta, China. Acyclovir was the only antiviral detected in the wastewater at 177-406 (mean=238) and 114-205 (mean=154) ng L(-1) in the influent and final effluent, respectively. Aerobic biodegradation appeared to be the main process for the elimination of acyclovir in the wastewater. Acyclovir was also the only antiviral quantitatively detected in the Pearl River and its tributaries, with a maximum concentration up to 113 ng L(-1). Treated wastewater was a major source of acyclovir in the rivers. The highest concentration of acyclovir was observed in winter in the river water and the dilution effect by precipitation was suggested to be the dominant factor impacting the seasonal pattern of acyclovir in the rivers. No antivirals were quantitatively detected in the well water whereas acyclovir was frequently detected in the reservoirs at a maximal concentration of 33.6 ng L(-1) in the vicinity of the municipal landfills. However, source identification and fate of acyclovir in the reservoirs pend on further research.

  5. Endocrine-disrupting chemicals in the Pearl River Delta and coastal environment: sources, transfer, and implications.

    Science.gov (United States)

    Xu, Weihai; Yan, Wen; Huang, Weixia; Miao, Li; Zhong, Lifeng

    2014-12-01

    A study was conducted to investigate the occurrence and behavior of six endocrine-disrupting chemicals (EDCs) in sewage, river water, and seawater from the Pearl River Delta (PRD). The six EDCs under study were 4-nonylphenol (NP), bisphenol A (BPA), 17α-ethynylestradiol (EE2), estrone (E2), 17β-estradiol (E2), and estriol (E3). These EDCs, predominated by BPA, were found in high levels in the influents and the effluents of sewage treatment plants in the area. The relatively high concentrations (0.23-625 ng/L) of the EDCs detected in the receiving river water suggested that the untreated sewage discharge was a major contributor. The EDCs detected in eight outlets of the Pear River and the Pear River Estuary were in the ranges of 1.2-234 and 0.2-178 ng/L, respectively. The estrogen equivalents in the aquatic environments under study ranged from 0.08 to 4.5 ng/L, with E1 and EE2 being the two predominant contributors. As the fluxes of the EDCs from the PRD region to the nearby ocean are over 500 tons each year, the results of this study point to the potential that Pearl River is a significant source of the EDCs to the local environment there.

  6. Effect of Atmospheric Haze on the Deterioration of Visibility over the Pearl River Delta

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The studies on the effect of atmospheric aerosol on climate and environment are hot issues in the current circle of international science and technology. In recent years the pollution of aerosol is getting worse and worse over the Pearl River Delta. The clouds of aerosol occur all year round, with heavy pollution area located at the western side at the mouth of Pearl River. The haze weather mainly occurs from October to April next year, resulting in visibility deterioration. From the beginning of 1980s, visibility dramatically deteriorated, obviously increasing haze weather, in which there are three big fluctuations, showing the periods of pollutions of dust, sulphate and dust, fine particle from photochemical process and sulphate and dust accompanying with the development of economy respectively. The long-term tendency of visibility caused by fog and light fog does not show a tendency due to human activities or economic development, which mainly shows the interannual and interdecadal variation of climate. The deterioration of visibility has close relation to the fine particles over Pearl River Delta, with half of PM10 overpass the limited value set by national second graded standard (150μg m-3), meanwhile, all values of PM2.5 overpass the day-mean limited value of American national standard (65μg m-3), especially from October to January next year, monthly mean values of PM2.5 almost reach two times of standard value, indicating the fine particle concentration is very high. The ratio of PM2.5 to PM10 is also very high, reaching 58%-77%, higher especially in dry season than in rainy season. Thus it is the fine particle pollution in aerosol pollution over the Pearl River Delta.Compared with the data of 15 years ago, the ratio of fine particle to aerosol has obviously increased.

  7. Environmental flows and its evaluation of restoration effect based on LEDESS model in Yellow River Delta wetlands

    NARCIS (Netherlands)

    Wang, X.G.; Lian, Y.; Huang, C.; Wang, X.J.; Wang, R.L.; Shan, K.; Pedroli, B.; Eupen, van M.; Elmahdi, A.; Ali, M.

    2012-01-01

    Due to freshwater supplement scarcity and heavy human activities, the fresh water wetland ecosystem in Yellow River Delta is facing disintegrated deterioration, and it is seriously affecting the health of the Yellow River ecosystem. This paper identifies the restoration objectives of wetland aiming

  8. Geomorphic change and sediment transport during a small artificial flood in a transformed post-dam delta: The Colorado River delta, United States and Mexico

    Science.gov (United States)

    Mueller, Erich R.; Schmidt, John C.; Topping, David J.; Shafroth, Patrick B.; Rodríguez-Burgueño, Jesús Eliana; Ramírez-Hernández, Jorge; Grams, Paul E.

    2016-01-01

    The Colorado River delta is a dramatically transformed landscape. Major changes to river hydrology and morpho-dynamics began following completion of Hoover Dam in 1936. Today, the Colorado River has an intermittent and/or ephemeral channel in much of its former delta. Initial incision of the river channel in the upstream ∼50 km of the delta occurred in the early 1940s in response to spillway releases from Hoover Dam under conditions of drastically reduced sediment supply. A period of relative quiescence followed, until the filling of upstream reservoirs precipitated a resurgence of flows to the delta in the 1980s and 1990s. Flow releases during extreme upper basin snowmelt in the 1980s, flood flows from the Gila River basin in 1993, and a series of ever-decreasing peak flows in the late 1990s and early 2000s further incised the upstream channel and caused considerable channel migration throughout the river corridor. These variable magnitude post-dam floods shaped the modern river geomorphology. In 2014, an experimental pulse-flow release aimed at rejuvenating the riparian ecosystem and understanding hydrologic dynamics flowed more than 100 km through the length of the delta’s river corridor. This small artificial flood caused localized meter-scale scour and fill of the streambed, but did not cause further incision or significant bank erosion because of its small magnitude. Suspended-sand-transport rates were initially relatively high immediately downstream from the Morelos Dam release point, but decreasing discharge from infiltration losses combined with channel widening downstream caused a rapid downstream reduction in suspended-sand-transport rates. A zone of enhanced transport occurred downstream from the southern U.S.-Mexico border where gradient increased, but effectively no geomorphic change occurred beyond a point 65 km downstream from Morelos Dam. Thus, while the pulse flow connected with the modern estuary, deltaic sedimentary processes were not

  9. Bathymetry, topography, and sediment grain-size data from the Elwha River delta, Washington, February 2016

    Science.gov (United States)

    Stevens, Andrew; Gelfenbaum, Guy R.; Warrick, Jonathan; Miller, Ian M.; Weiner, Heather M.

    2016-01-01

    Two dams on the Elwha River, Washington State, USA trapped over 20 million m3 of sediment, reducing downstream sediment fluxes and contributing to erosion of the river's coastal delta. The removal of the Elwha and Glines Canyon dams between 2011 and 2014 induced massive increases in river sediment supply and provided an unprecedented opportunity to examine the response of a delta system to changes in sediment supply. The U.S. Geological Survey (USGS) developed an integrated research program aimed at understanding the ecosystem responses following dam removal. The research program included repeated surveys of beach topography, nearshore bathymetry, and surface sediment grain size to quantify changes in delta morphology and texture following the dam removals. For more information on the USGS role in the Elwha River Restoration Project, please visit http://walrus.wr.usgs.gov/elwha/. This USGS data release presents data collected during surveys of nearshore bathymetry, beach topography, and surface sediment grain size from the Elwha River delta, Washington. Survey operations were conducted between February 15 and February 19, 2016 (USGS Field Activity Number 2016-608-FA) by a team of scientists from the U.S. Geological Survey Pacific Coastal and Marine Science Center (PCMSC), Washington State Department of Ecology (WA DOE), Washington Sea Grant, and National Park Service (table 1). Nearshore bathymetry data were collected using two personal watercraft (PWCs) and a kayak, each equipped with single-beam echosounders and survey-grade global navigation satellite systems (GNSS). Topography data were collected on foot with GNSS mounted on backpacks. Positions of the survey platforms were referenced to a GNSS base station placed on a nearby benchmark with known horizontal and vertical coordinates. Depths from the echosounders were computed using sound velocity profiles measured with a conductivity-temperature-depth (CTD) sensor during the survey. A total of 126 km of

  10. Late Quaternary strata and carbon burial records in the Yellow River delta, China

    Science.gov (United States)

    Zhao, Guangming; Ye, Siyuan; Li, Guangxue; Ding, Xigui; Yuan, Hongming

    2015-06-01

    Sediment carbon sequestration plays an essential role in mitigating atmospheric CO2 increases and the subsequently global greenhouse effect. To clarify the late Quaternary strata and carbon burial records in Yellow River delta (YRD), detailed analysis of benthic foraminifera, total carbon (TC), organic carbon (Corg), sedimentary characteristics and moisture contents of sediments, was performed on core ZK3, 30.3 m in length and obtained from YRD in 2007. Eight depositional units (designated U1-U8 in ascending order) were identified. A comprehensive analysis method of historical geography and sedimentary geology was used to determine the precise depositional ages of the modern Yellow River delta (MYRD), from which pre-MYRD ages were deduced. The results indicates that the maximum burial rates of TC, inorganic carbon (IC) and Corg occurred in the delta front (U5), and the minimum in the shallow sea (U3). Remarkable high sedimentation rates in the MYRD are responsible for burial efficiency of carbon, with an average rate of Corg burial reaching 2087±251 g (m2 yr)-1, and that of IC reaching 13741±808 g (m2 yr)-1, which are much higher than those of other regions with high contents of Corg. Therefore, YRD has a significant burial efficiency for carbon sequestration.

  11. Impacts of Weather Conditions Modified by Urban Expansion on Surface Ozone:Comparison between the Pearl River Delta and Yangtze River Delta Regions

    Institute of Scientific and Technical Information of China (English)

    WANG Xuemei; CHEN Fei; WU Zhiyong; ZHANG Meigen; Mukul TEWARI; Alex GUENTHER; Christine WIEDINMYER

    2009-01-01

    In this paper,the online weather research and forecasting and chemistry (WRF-Chem) model is used to explore the impacts of urban expansion on regional weather conditions and its implication on surface ozone concentrations over the Pearl River Delta(PRD) and Yangtze River Delta(YRD) regions.Two scenarios of urban maps are used in the WRF-Chem to represent the early 1990s (pre-urbanization) and the current urban distribution in the PRD and the YRD.Month-long simulation results using the above land-use scenarios for March 2001 show that urbanization increases both the day- and night-time 2-m temperatures by about 0.6℃ and 1.4℃,respectively. Daytime reduction in the wind speed by about 3.0 m s-1 is larger than that for the nighttime (0.5 to 2 m s-1).The daytime increase in the PBL height (>200 m) is also larger than the nighttime (50-100 m).The meteorological conditions modified by urbanization lead to detectable ozone-concentration changes in the PRD and the YRD.Urbanization increases the nighttime surface-ozone concentrations by about 4.7%-8.5% and by about 2.9%-4.2% for the daytime.In addition to modifying individual meteorological variables,urbanization also enhances the convergence zones,especially in the PRD.More importantly,urbanization has different effects on the surface ozone for the PRD and the YRD,presumably due to their urbanization characteristics and geographical locations.Even though the PRD has a smaller increase in the surface temperature than the YRD,it has (a) weaker surface wind speed,(b)smaller increase in PBL heights,and (c) stronger convergence zones.The latter three factors outweighed the temperature increase and resulted in a larger ozone enhancement in the PRD than the YRD.

  12. Antibiotics in riverine runoff of the Pearl River Delta and Pearl River Estuary, China: concentrations, mass loading and ecological risks.

    Science.gov (United States)

    Xu, Weihai; Yan, Wen; Li, Xiangdong; Zou, Yongde; Chen, Xiaoxiang; Huang, Weixia; Miao, Li; Zhang, Ruijie; Zhang, Gan; Zou, Shichun

    2013-11-01

    Ten antibiotics belonging to three groups (macrolides, fluoroquinolones and sulfonamides) were investigated in riverine runoff of the Pearl River Delta (PRD) and Pearl River Estuary (PRE), South China for assessing the importance of riverine runoff in the transportation of contaminants from terrestrial sources to the open ocean. All antibiotics were detected in the eight outlets with concentrations ranging from 0.7 to 127 ng L(-1). The annual mass loadings of antibiotics from the PRD to the PRE and coast were 193 tons with 102 tons from the fluoroquinolone group. It showed that antibiotics decreased from the riverine outlets to the PRE and open ocean. Risk assessment showed that most of these antibiotics showed various ecological risks to the relevant aquatic organisms, in which ofloxacin (OFL), erythromycin (ETM) and ciprofloxacin (CIP) posed high ecological risks to the studied aquatic environments.

  13. Transport and Vulnerability in River Deltas: A Graph-Theoretic Approach

    CERN Document Server

    Tejedor, Alejandro; Zaliapin, Ilya; Foufoula-Georgiou, Efi

    2014-01-01

    Maintaining a sustainable socio-ecological state of a river delta requires delivery of material and energy fluxes to its body and coastal zone in a way that avoids malnourishment that would compromise system integrity. We present a quantitative framework for studying delta topology and transport based on representation of a deltaic system by a rooted directed acyclic graph. Applying results from spectral graph theory allows systematic identification of the upstream and downstream subnetworks for a given vertex, computing steady flux propagation in the network, and finding partition of the flow at any channel among the downstream channels. We use this framework to construct vulnerability maps that quantify the relative change of sediment and water delivery to the shoreline outlets in response to possible perturbations in hundreds of upstream links. This enables us to evaluate which links hotspots and what management scenarios would most influence flux delivery to the outlets. The results can be used to examine...

  14. Discussion on Forestry Sustainable Development in the Yellow River Delta Region

    Institute of Scientific and Technical Information of China (English)

    SUN Qixiang; ZHANG Jianfeng

    2006-01-01

    The Yellow River Delta (YRD) is one of the biggest deltas that have not been developed in the world.During the turn of the centuries, YRD development is listed in the two major projects in the new century by Shandong provincial government.According to the plan, YRD will become an important energy, chemical and agricultural production base in 15-20 years.In view of its location and natural conditions, so far there exist a lot of environmental problems in YRD.Thus the principle of economic development coordinating with environmental protection must be implemented during YRD development.Forestation is one of the vital measures to cope with environment degradation.Therefore, strategies of forestry development and techniques of tree planting in different land use types are discussed in the paper based on site classification with specific problems involved .

  15. Spatial Variability of Salt Ions in Soils in Oasis of Delta of Weigan River-Kuqa River in Different Seasons

    Institute of Scientific and Technical Information of China (English)

    Yuanyuan XU; Tashpolat TIYIP; Fei ZHANG; Jun XIA; Guihong HAN; Mamat SAWUT

    2012-01-01

    Abstract [Objective] The aim was to research the spatial variability of salts' ions in soils of oases of Weigan River-Kuqa River to explore spatial correlation among soil ions and effects of seasonal changes on distribution of eight ions in soils. [Method] Based on soil salinizaiton, temporal and spatial distributions of eight ions in surface soils were researched and distribution maps were drawn with the help of classical statistics and geostatistics. [Result] All contents of salt ions were proved in consistent with normal distribution by K-S test, and variability of the ions changed with season, for example, variability of ions in soils in October was higher than that in April, which might be caused by little rainfall and high evaporation in October. It can be concluded from semivariance analysis that salt ions were all of high spatial autocorrelation. In addition, it can be concluded from spatial distribution that spatial structures of most ions are reasonable, except Ca2+ and Mg2' in soils collected in April of 2010 and Mg2+ in October of 2010, which were more suitable for linear model, and chloride-sulfate dominated in salinized soils in the researching area. [Conclusion] The research laid foundation for partition, improvement and use of salin- ized soils in delta of Weigan River-Kuqa River.

  16. [Integrated assessment of eco-environmental vulnerability in Pearl River Delta based on RS and GIS].

    Science.gov (United States)

    Xu, Qing-Yong; Huang, Mei; Liu, Hong-Sheng; Yan, Hui-Min

    2011-11-01

    Based on the remote sensing data and with the help of geographic information system, an integrated assessment was conducted on the eco-environmental vulnerability of Pearl River Delta in 2004-2008. Spatial principal component analysis was used to generate the evaluation indicators, and analytic hierarchy process (AHP) was applied to determine the weights of the evaluation factors. The reasons causing the vulnerability of the eco- environment in Pearl River Delta were discussed. In the study area, its middle part was the most vulnerable region, occupying 34.0% of the total, eastern part was the moderately vulnerable region, accounting for 25.5%, and western part was the lightly and slightly vulnerable areas, accounting for 28.7 and 11.8%, respectively. Totally, the moderately and lightly vulnerable areas occupied 54.2%, indicating that a majority of the Delta was under moderate and light vulnerability. The natural factors affecting the eco-environmental vulnerability of the Delta were altitude, heavy rain days, water and soil erosion rate, flooded infield rate, normalized difference vegetation index (ND VI) and landscape diversity index, whereas the human factors were population density, waste discharge per unit area, exhaust emission per unit area, land use change, chemical fertilization intensity, pesticide application intensity, amount of motor vehicles possessed by ten thousands people, and index of environmental protection investment. The main characteristics of the extremely and heavily vulnerable regions were low altitude, high frequency of flood disaster, large flooded infield, serious vegetation degradation, high pollution level and low environment protection investment index.

  17. Financial Impacts of Priority Swine Diseases to Pig Farmers in Red River and Mekong River Delta, Vietnam.

    Science.gov (United States)

    Pham, H T T; Antoine-Moussiaux, N; Grosbois, V; Moula, N; Truong, B D; Phan, T D; Vu, T D; Trinh, T Q; Vu, C C; Rukkwamsuk, T; Peyre, M

    2017-08-01

    A study was conducted between May 2013 and August 2014 in three provinces of Vietnam to investigate financial impacts of swine diseases in pig holdings in 2010-2013. The aim of the study was to quantify the costs of swine diseases at producer level in order to understand swine disease priority for monitoring at local level. Financial impacts of porcine reproductive and respiratory syndrome (PRRS), foot and mouth disease (FMD), and epidemic diarrhoea were assessed for 162 pig holders in two Red River Delta provinces and in one Mekong River Delta province, using data on pig production and swine disease outbreaks at farms. Losses incurred by swine diseases were estimated, including direct losses due to mortality (100% market value of pig before disease onset) and morbidity (abortion, delay of finishing stage), and indirect losses due to control costs (treatment, improving biosecurity and emergency vaccination) and revenue foregone (lower price in case of emergency selling). Financial impacts of swine diseases were expressed as percentage of gross margin of pig holding. The gross margin varied between pig farming groups (P swine disease priorities to better inform surveillance and control at both national and local level. © 2016 Blackwell Verlag GmbH.

  18. Spatial distribution and partition of perfluoroalkyl acids (PFAAs) in rivers of the Pearl River Delta, southern China.

    Science.gov (United States)

    Liu, Baolin; Zhang, Hong; Xie, Liuwei; Li, Juying; Wang, Xinxuan; Zhao, Liang; Wang, Yanping; Yang, Bo

    2015-08-15

    This study investigated the occurrence of perfluoroalkyl acids (PFAAs) in surface water from 67 sampling sites along rivers of the Pearl River Delta in southern China. Sixteen PFAAs, including perfluoroalkyl carboxylic acids (PFCAs, C5-14, C16 and C18) and perfluoroalkyl sulfonic acids (PFSAs, C4, C6, C8 and C10) were determined by high performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Total PFAA concentrations (∑ PFAAs) in the surface water ranged from 1.53 to 33.5 ng·L(-1) with an average of 7.58 ng·L(-1). Perfluorobutane sulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS) were the three most abundant PFAAs and on average accounted for 28%, 16% and 10% of ∑ PFAAs, respectively. Higher concentrations of ∑ PFAAs were found in the samples collected from Jiangmen section of Xijiang River, Dongguan section of Dongjiang River and the Pearl River flowing the cities which had very well-developed manufacturing industries. PCA model was employed to quantitatively calculate the contributions of extracted sources. Factor 1 (72.48% of the total variance) had high loading for perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA), PFBS and PFOS. For factor 2 (10.93% of the total variance), perfluorononanoic acid (PFNA) and perfluoroundecanoic acid (PFUdA) got high loading. The sorption of PFCAs on suspended particulate matter (SPM) increased by approximately 0.1 log units for each additional CF2 moiety and that on sediment was approximately 0.8 log units lower than the SPM logKd values. In addition, the differences in the partition coefficients were influenced by the structure discrepancy of absorbents and influx of fresh river water. These data are essential for modeling the transport and environmental fate of PFAAs.

  19. Epidemiological investigation of Clonorchis sinensis infection in freshwater fishes in the Pearl River Delta.

    Science.gov (United States)

    Chen, Daixiong; Chen, Jieyun; Huang, Ji; Chen, Xueying; Feng, Dana; Liang, Baofang; Che, Yuchuan; Liu, Xiaodan; Zhu, Cuihua; Li, Xiaomin; Shen, Haoxian

    2010-09-01

    Pearl River Delta region is a high clonorchiasis-endemic area in China. However, no complete epidemiological data exist regarding its infection in freshwater fishes, an important epidemic factor for Clonorchis sinensis. The present study collected freshwater fishes and shrimps from 32 sites of nine cities in the Pearl River Delta, and the encysted metacercariae of C. sinensis were detected by digesting these specimens with artificial gastric juice. The mean infection rate of freshwater fishes was 37.09% (2,160/5,824) with a mean number of 14.269 encysted metacercariae in every infected fish and 0.460 encysted metacercariae in every gram of fish meat. Of these freshwater fishes, 5,219 were domesticated, and the infection rate was 36.69% with a mean number of 10.743 encysted metacercariae in every infected fish and 0.312 encysted metacercariae in every gram of fish meat; the other 605 were wild, and the infection rate was 40.50% with a mean number of 41.829 encysted metacercariae in every infected fish and 8.812 encysted metacercariae in every gram of fish meat. A total of 228 shrimps were examined, and 3.07% of them were infected with a mean number of 1.00 encysted metacercariae in every infected shrimp. Pseudorasbora parva and Ctenopharyngodon idellus had the highest infection rate and degree of infection in the fishes studied. The results demonstrated a high incidence of C. sinensis infection in freshwater fishes and shrimps within Pearl River Delta region and a great difference in the infection rate among different collection sites and different fish species.

  20. Regional dynamics of persistent organic pollutants (POPs) in the Pearl River Delta, China: Implications and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Kai [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China); Zhang Baozhong [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li Shaomeng [Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4 (Canada); Zeng, Eddy Y., E-mail: eddyzeng@gig.ac.cn [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2011-10-15

    The mass transport budgets of 1,1,1-trichloro-2,2-bis(chlorophenyl)ethane (p,p'-DDT) and decabromodiphenyl ether (BDE-209) in the Pearl River Delta, South China were calculated based on previously collected data. Residual p,p'-DDT, mostly related to historical use, has largely settled into soil (780,000 kg), while the soil BDE-209 inventory (44,000 kg) is considerably smaller. Conversely, large amounts of BDE-209 currently used in numerous commercial products have resulted in a much higher atmospheric depositional flux of BDE-209 (28,100 kg/yr) relative to p,p'-DDT (310 kg/yr). The soil inventory of p,p'-DDT is predicted to decrease to half of its current value after 22 years, and the percent area containing soil p,p'-DDT at levels exceeding the effects range-medium (27 ng/g) will decrease from 40% to 20%. Finally, soil BDE-209 inventory will reach an equilibrium value of 940 tons in {approx}60 years, when BDE-209 levels in 50% of soil will be above an equivalent risk guideline value (125 ng/g). - Highlights: > Transport budgets of p,p'-DDT and BDE-209 in the Pearl River Delta were built. > Dry aerial deposition is the dominant route to transport p,p'-DDT and BDE-209. > Soil inventory of p,p'-DDT is much larger than that of BDE-209. > Soil inventory of p,p'-DDT would decline to half of its current value in 22 years. > Soil BDE-209 inventory is expected to reach an equilibrium value in {approx}60 years. - Regional dynamics of p,p'-DDT and BDE-209 in the Pearl River Delta (South China) are examined and used to predict temporal variances.

  1. Refining the link between the Holocene development of the Mississippi River Delta and the geologic evolution of Cat Island, MS: implications for delta-associated barrier islands

    Science.gov (United States)

    Miselis, Jennifer L.; Buster, Noreen A.; Kindinger, Jack G.

    2014-01-01

    The geologic evolution of barrier islands is profoundly influenced by the nature of the deposits underlying them. Many researchers have speculated on the origin and evolution of Cat Island in Mississippi, but uncertainty remains about whether or not the island is underlain completely or in part by deposits associated with the past growth of the Mississippi River delta. In part, this is due to a lack of comprehensive geological information offshore of the island that could augment previous stratigraphic interpretations based on terrestrial borings. An extensive survey of Cat Island and its surrounding waters was conducted, including shallow-water geophysics (e.g., high-resolution chirp seismic, side-scan sonar, and swath and single-beam bathymetry) and both terrestrial and marine vibracoring. High-resolution seismic data and vibracores from south and east of the island show two horizontally laminated silt units; marine radiocarbon dates indicate that they are St. Bernard delta complex (SBDC) deposits. Furthermore, seismic data reveal that the SBDC deposits taper off toward the southern shoreline of Cat Island and to the west, morphology consistent with the distal edge of a delta complex. The sedimentology and extent of each unit suggest that the lower unit may have been deposited during an earlier period of continuous river flow while the upper unit may represent reduced or sporadic river flow. OSL dates from the island platform (beneath beach ridge complexes) indicate three stages of terrestrial evolution: island emergence resulting from relative sea-level rise (~ 5400 ybp) island aggradation via littoral transport (~ 2500–4000 ybp) and island degradation due to delta-mediated changes in wave direction (present– ~ 3600 ybp). Finally, the combination of terrestrial and marine data shows that portions of Cat Island that are lower in elevation than the central part of the island are younger and are likely underlain by a thin layer of deltaic sediments. This

  2. [Characteristics Analysis of Sulfur Dioxide in Pearl River Delta from 2006 to 2010].

    Science.gov (United States)

    Li, Fei; Tan, Hao-bo; Deng, Xue-jiao; Deng, Tao; Xu, Wan-yun; Ran, Liang; Zhao, Chun-sheng

    2015-05-01

    Based on the in-situ SO2 observation dataset from 2006 to 2010 in Pearl River Delta(PRD) , the temporal characteristics of SO2 are analyzed. The results show that the annual average volume fraction of surface SO2 in 2010 declines to a level below average values in recent years, with reducing the frequency of high concentration episodes occurring. The seasonal, monthly and diurnal characteristics of surface SO2 are influenced by particular weather conditions in the PRD. The Probability Distribution Function(PDF) of surface SO2 volume fraction are complicated. The PDF is different every month maybe caused by the variation of the seasonal factors.

  3. The S1 buoy station, Po River delta: data handling and presentation

    Directory of Open Access Journals (Sweden)

    Alessandro COLUCCELLI

    2006-12-01

    Full Text Available The technical setting of the mete-oceanographic buoy at site S1 south of the Po River delta is presented. The station was deployed by Istituto di Scienze Marine (ISMAR of CNR of Bologna, in cooperation with the local Regional Government and Environmental Agencies (ARPA of E. Romagna, and ADRICOSM. The buoy mooring and data flow architecture is discussed, with some emphasis on the WWW data presentation. The possible integration with other remote stations, data and mete-oceanographic operational activities is also proposed.

  4. Surface Water Pollution in the Yangtze River Delta:Patterns and Countermeasures

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    On the basis of field investigations, observations and experimental data combined with environmental monitoring information, the status and the spatial and temporal patterns of surface water pollution over the past ten years in the Yangtze River Delta have been assessed. The water quality of large rivers is still very good but most of the medium-sized and small rivers have been very seriously polluted. The appearance of black and odorous conditions in rivers in the urban areas has increased due to serious pollution by organic matter with consequent high oxygen demand. Annual increases in N and P concentrations in lakes have accelerated eutrophication. The water quality of rivers in small towns is rapidly deteriorating. The main sources of surface water pollution include industrial and domestic sewage, animal manures, chemical fertilizers in farmland, and polluted sediments in rivers and lakes.Countermeasures against these sources of pollution are presented. Regional laws and regulations for protection of surface waters and their enforcement are urgently required. A regional water environmental management agency should be established. The construction of sewage treatment plants of varying capacity must be accelerated to increase the proportion of sewage treated and to improve the quality of treated effluent. Animal wastes must be recycled effectively and efficiently, and the application rates of fertilizers and manures must be balanced with crop nutrient requirements to prevent diffuse pollution from agriculture.The comprehensive rehabilitation of medium-sized and small rivers should be intensified, and the delimitation and protection of the areas used as sources of drinking water should be strengthened.

  5. Controls of {delta}{sup 34}S and {delta}{sup 18}O in dissolved sulphate: Learning from a detailed survey in the Llobregat River (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Otero, Neus [Departament Cristal . lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028 Barcelona (Spain); Grup d' Hidrogeoquimica, Departament de Geologia Ambiental, Institut de Ciencies de la Terra ' Jaume Almera' , CSIC, Lluis Sole i Sabaris, s/n, 08028 Barcelona (Spain)], E-mail: notero@ub.edu; Soler, Albert; Canals, Angels [Departament Cristal . lografia, Mineralogia i Diposits Minerals, Facultat de Geologia, Universitat de Barcelona, Marti i Franques, s/n, 08028 Barcelona (Spain)

    2008-05-15

    The S and O isotopic composition of dissolved SO{sub 4}, used as a tracer for SO{sub 4} sources, was applied to the water of the Llobregat River system (NE Spain). The survey was carried out at 30 sites where surface water was sampled on a monthly basis over a period of 2a. The concentration of dissolved SO{sub 4} varied from 20 to 1575 mg L{sup -1}. Sulphur isotopic compositions clustered in two populations: one - 93% of the samples - had positive values with a mode of +9 per mille ; the other had negative values and a mode of -5 per mille . Data for {delta}{sup 18}O{sub SO{sub 4}} showed a mean value of +11 per mille , with no bi-modal distribution, though lower values of {delta}{sup 18}O corresponded to samples with negative {delta}{sup 34}S. These values can not be explained solely by the contribution of bedrock SO{sub 4} sources: that is, sulphide oxidation and the weathering of outcrops of sulphates, though numerous chemical sediments exist in the basin. Even in a river with a high concentration of natural sources of dissolved SO{sub 4}, such as the Llobregat River, the {delta}{sup 34}S values suggest that dissolved SO{sub 4} is controlled by a complex mix of both natural and anthropogenic sources. The main anthropogenic sources in this basin are fertilizers, sewage, potash mine effluent and power plant emissions. Detailed river water sampling, together with the chemical and isotopic characterisation of the main anthropogenic inputs, allowed determination of the influence of redox processes, as well as identification of the contribution of natural and anthropogenic SO{sub 4} sources and detection of spatial variations and seasonal changes among these sources. For instance, in the Llobregat River the input of fertilisers is well marked seasonally. Minimum values of {delta}{sup 34}S are reported during fertilization periods - from January to March - indicating a higher contribution of this source. The dual isotope approach, {delta}{sup 34}S and {delta}{sup 18}O

  6. Distribution, sources, and fluxes of heavy metals in the Pearl River Delta, South China.

    Science.gov (United States)

    Geng, Junjie; Wang, Yiping; Luo, Hanjin

    2015-12-30

    Riverine samples were collected at various locations in the Pearl River Delta (PRD) to determine the concentrations of heavy metals (Cr, Ni, Cu, Mn, Zn, Cd, and Pb) in time and space and to estimate the fluxes of heavy metals to the coastal waters off South China. Most of the elements exhibit clear temporal and spatial trends. Principal component analysis shows that surface erosion is the major factor affecting metal concentrations in particulates in the PRD. Natural geology is an important source of these heavy metals. The annual fluxes of Cr, Ni, Cu, Mn, Zn, Cd, and Pb in upstream and downstream were 445, 256, 241, 3293, 1279, 12, and 317 t/year and 1823, 1144, 1786, 15,634, 6183, 74, and 2017 t/year, respectively. A comparison indicated that the annual fluxes of Mn accounted for 1.3% of the global river fluxes, whereas other elements contribute <1%.

  7. [Hydrochemical characteristics and formation mechanism of shallow groundwater in the Yellow River Delta].

    Science.gov (United States)

    An, Le-Sheng; Zhao, Quan-Sheng; Ye, Si-Yuan; Liu, Guan-Qun; Ding, Xi-Gui

    2012-02-01

    Understanding the chemical characteristics of groundwater in the Yellow River Delta is very important. It can provide a useful reference for the development and construction of the Yellow River Delta High-efficiency Ecological Economic Zone and ecological regulation in the lower Yellow River. Based on partitioning the sediment environment and the recharge-runoff-discharge system, we studied the hydrochemical features and causes of shallow groundwater in the Yellow River Delta by mathematical statistics and geostatistics, Piper diagram, ion ratios and so on. Following results are obtained: 1) Major cations and anions such as Na+, Mg2+, Ca2+, Cl(-), SO4(2-), HCO3(-) and TDS concentrations range from 0.1-25.0 g x L(-1), 3.6-3 815.0 mg x L(-1), 5.6-3 377.0 mg x L(-1), 0.1-45.1 g x L(-1), 24.2-4 947.0 mg x L(-1), 62.6-850.0 mg x L(-1) and 0.4-80.7 g x L(-1). Average ion concentrations further indicate that Cl(-), Na+ and TDS concentrations are high while HCO3(-), CO3(2-) and K+ concentrations are very low in the study area. 2) The Cl(-) and TDS concentrations of shallow groundwater possess conspicuous directional spatial variability and gradually increase along the groundwater flow direction, showing that Cl(-) is the most critical ion of shallow groundwater. 3) From the recharge area to the discharge area, shallow groundwater changes from the Na+ -Mg2+ -Ca2+ -Cl(-) -SO4(2-) facies to the Na -Mg2 + -Ca2+ -Cl(-), Mg2+ -Na+ -Ca2+ -Cl(-) and Na+ -Mg2+ -Cl(-) facies, finally evolves into Na+ -Cl(-) facies in the coast. 4) Ion ratios indicate that the following main hydrochemical processes are inferred to control the shallow groundwater chemical composition: mixing, evaporation concentrating, mineral dissolution, cation exchange and adsorption and human activities. These findings strongly suggest that changes of the Yellow River water course and seawater intrusion are key drivers to form the chemical characteristics of shallow groundwater in the region.

  8. Geoarchaeological research for Roman waterworks in the Rhine-Meuse river delta, the Netherlands

    Science.gov (United States)

    Verhagen, Jan; Kluiving, Sjoerd; van Leeuwen, Liz; Anker, Emiel

    2015-04-01

    It is known that Romans in the Low Countries at the northern margin of their empire were practicing diverse systems of water state management to maintain economic and above all strategic stability. In early Roman period Romans created a shipping route from the Rhine towards the north by digging canals and constructing dams. This was done in order to submit the northern part of Germania through the Waddenzee and the German rivers Eems, Weser and Elbe. During the middle Roman period the Romans had canceled their efforts to submit Germania. In that period we know the River Rhine as the limes, which not only was a borderline of the Roman empire, but can also be seen as a guarded transport route. The research area is situated in the eastern part of the Rhine-Meuse river valley/delta system. The area represents a highly dynamic geological history of erosion and deposition close to the river system's equilibrium point. In order to reconstruct the former landscape and investigate whether traces of Roman waterworks could be indicated or disproved geoarchaeological coring campaigns have been carried out with lithological, textural and palaeoecological analyses. The results of the research presented in this poster will be: 1) Assessment of the condition of the covered Pleistocene sediments in the area, 2) Identification of the buried gullies and levees in the vicinity of the remains of the Roman castellum 'Carvium ad molem', which should have been built at the bifurcation of the delta branches of Rhine and Waal, 3) Chronological control of gullies and levees, 4) Landscape reconstruction in different time periods. Finally based on the geoarchaeological results a comment will be made on the location of the Drusus dam in the study area, the landscape context of the castellum and its position on the apex of the Insula Batavorum.

  9. Coastal processes of the Elwha River delta: Chapter 5 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

    Science.gov (United States)

    Warrick, Jonathan A.; Stevens, Andrew W.; Miller, Ian M.; Gelfenbaum, Guy; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

    2011-01-01

    To understand the effects of increased sediment supply from dam removal on marine habitats around the Elwha River delta, a basic understanding of the region’s coastal processes is necessary. This chapter provides a summary of the physical setting of the coast near the Elwha River delta, for the purpose of synthesizing the processes that move and disperse sediment discharged by the river. One fundamental property of this coastal setting is the difference between currents in the surfzone with those in the coastal waters offshore of the surfzone. Surfzone currents are largely dictated by the direction and size of waves, and the waves that attack the Elwha River delta predominantly come from Pacific Ocean swell from the west. This establishes surfzone currents and littoral sediment transport that are eastward along much of the delta. Offshore of the surfzone the currents are largely influenced by tidal circulation and the physical constraint to flow provided by the delta’s headland. During both ebbing and flooding tides, the flow separates from the coast at the tip of the delta’s headland, and this produces eddies on the downstream side of the headland. Immediately offshore of the Elwha River mouth, this creates a situation in which the coastal currents are directed toward the east much more frequently than toward the west. This suggests that Elwha River sediment will be more likely to move toward the east in the coastal system.

  10. A review of environmental and human exposure to persistent organic pollutants in the Pearl River Delta, South China.

    Science.gov (United States)

    Zhang, Kai; Wei, Yan-Li; Zeng, Eddy Y

    2013-10-01

    Rapid economic growth in South China (including Guangdong Province, Hong Kong, and Macau), particularly within the Pearl River Delta region, has resulted in severe pollution of the natural eco-environment in the last three decades. Large amounts of monitoring data on organic pollution in the Pearl River Delta have been accumulated, which allows us to conduct a fairly comprehensive assessment of the state of the Pearl River Delta and elucidate spatial and temporal patterns of pollution on a regional scale. Of various causes for environmental deterioration, negative impact from persistent organic pollutants (POPs) is a global concern. This review examines the current levels and distribution patterns of several POPs, namely DDT (and its metabolites DDD and DDE), hexachlorocyclohexanes, and polybrominated diphenyl ethers, in various environmental compartments of South China. The general information on environmental occurrence, regional behaviors, ecological effects, and human exposure of these POPs in this region are reviewed.

  11. Multibeam Mapping of Active Slope Instability Features: Examples from the Fraser River and Squamish River Deltas, British Columbia, Canada

    Science.gov (United States)

    Hill, P. R.

    2004-12-01

    Multibeam mapping of the coastal waters of British Columbia has immensly improved our ability to identify and assess submarine landslide and tsunami hazard. This paper will present analysis of high-resolution images of slope instability features from two delta slopes where recent slope failure can be documented through repetitive multibeam mapping and/or comparison with previous single-beam hydrographic soundings. Numerous mass movement features characterize the slope of the Fraser River delta, all the recent features being located at the mouths of distributary channels. Engineering works have maintained the main channel in a fixed position since the 1930's, contributing to over-steepening of the slope and development of a network of submarine channels. Repetitive multibeam mapping shows that recent slope failures have occurred in numerous locations around the main channel lobe, some at the head of a large submarine channel system and others as isolated small failures that form the headwalls of small submarine channels. The scalloped morphology and association with channels, together with volume estimates derived from repetitive multibeam mapping, indicate that these features result from shallow, small volume liquefaction failures. Smaller scale, shallow slides are present on the very shallow water slope area adjacent to the channels, raising the possibility of groundwater seepage as an influence on slope stability. The slide masses from these failures are rapidly transformed into gravity flows that carve the submarine channels. Slides and channels of a similar scale are found at the mouth of a secondary distributary channel and an abandoned distributary channel. The multibeam imagery allows discrimination between recent slide features and relict features, the latter showing infilling or reworking by bottom currents. An area of undulatory seafloor, located on the flank of the main distributary channel lobe, has been cited as a possible creep displacement feature

  12. Mineralization pathways of organic matter deposited in a river-lake transition of the Rhone River Delta, Lake Geneva.

    Science.gov (United States)

    Randlett, Marie-Eve; Sollberger, Sebastien; Del Sontro, Tonya; Müller, Beat; Corella, Juan Pablo; Wehrli, Bernhard; Schubert, Carsten J

    2015-02-01

    During the éLEMO endeavour (a research project in which the Russian MIR submersibles were used for studying Lake Geneva) four sediment cores were retrieved on a transect from the delta of the Rhone River towards the profundal part of the lake. The degradation pathways of organic material (OM) were investigated considering different electron acceptors. Essentially, OM at the delta sites had a higher fraction of terrestrial material than the lake sites indicated by higher C/N ratios, and higher long-chain n-alkane and alcohol concentrations. The concentrations of chlorins were higher at the distant sites indicating more easily degradable OM in the sediments. However, the chlorin index that was used to determine the degradation state of the OM material indicated that pigment derived OM of deltaic sediments was less degraded than that of the profundal sediments. The fluxes of reduced species from the sediments decreased from the delta to the profundal for CH4 (from 2.3 to 0.5 mmol m(-2) d(-1)) and NH4(+) (from 0.31 to 0.13 mmol m(-2) d(-1)). Fluxes of Fe(ii) and Mn(ii), however, increased although they were generally very low (between 9 × 10(-5) and 7.6 × 10(-3) mmol m(-2) d(-1)). Oxygen concentration profiles in the pore waters revealed lower fluxes close to the river inflow with 4.3 and 4.1 mmol m(-2) d(-1) compared to two times higher fluxes at the profundal sites (8.8 and 8.2 mmol m(-2) d(-1)). The rates for totally mineralized OM (Rtotal) at the shallower sites (4.7 mmol C m(-2) d(-1)) were only half of those of the deeper sites (9.7 mmol C m(-2) d(-1)). Accordingly, not only the rates but also the mineralization pathways differed between the shallow and profundal sites. Whereas only 0-6% of the OM was mineralized aerobically at the shallow sites (since almost all O2 was used to oxidize the large flux of CH4 from below) the situation was reversed at the deeper sites and the fraction of aerobically degraded OM was 72-78%. We found a better efficiency in CH4

  13. River avulsions in the presence of tectonic tilting, and the Ganges-Brahmaputra Delta

    Science.gov (United States)

    Reitz, M. D.; Steckler, M. S.; Paola, C.; Goodbred, S. L.; Petter, A. L.; Pickering, J.; Williams, L. A.

    2013-12-01

    In Bangladesh, the set of active rivers of the Ganges-Brahmaputra Delta overlie a landscape that is being continually modified by tectonics. The response of rivers to a surface being altered by tectonic tilting or other causes of spatially variable subsidence is generally understood to be a preferred path direction toward regions of higher subsidence. Quantifying the magnitude of the effect of variable subsidence on the timescale and path direction of channel avulsion remains, however, an open question. Recent experimental work has suggested an equilibrium-slope explanation for the timescale and conditions for avulsion, which provides a way forward on understanding how varied subsidence conditions would affect the avulsion process. Here we adapt this model for avulsion to the context of variable subsidence, developing a new framework to quantify its effect on channel avulsions. We find that variable subsidence results in two effects: differing timescales between avulsions on different parts of the delta, and differing frequencies of avulsion to these locations. Regions of higher subsidence both draw avulsions more frequently, and result in longer channel residence times in these locations. We also describe the effect of incision or aggradation due to sea level changes within this framework: incisional events lengthen avulsion timescales everywhere on the delta, while periods of sea-level rise drive the timescales back toward their minimum values. Finally, we apply this theory to the Ganges-Brahmaputra Delta, where we use a map of regional variable subsidence that we derived from GPS and published stratigraphic data, to predict the variation in avulsion timescale and frequency for the Brahmaputra River due to this variable subsidence. We make estimates for two different tectonic history interpretations, and for the cases with or without the estimated incision from the most recent sea-level fall. Comparison between our predictions and our stratigraphy

  14. Simulation of temporal and spatial change of N2O emissions in the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-dong; ZHOU Xiu-ji; CHEN De-liang; OUYANG Zhi-yun; WANG Xiao-ke; Achberger Christine

    2005-01-01

    A biogeochemical model(DNDC) is combined with a plant ecological model to estimate N2O emission from rice paddy fields in the Yangtze River Delta region. The model is driven by local meteorological, soil, and physiological data and is validated for 1999 and 2000 at a site in the region, which showed that the simulated N2O emissions agree fairly well with the observed data. This adds some confidence in the estimated N2O emissions during 1950 and 2000 in the Hangzhou Region. A significant correlation between the N2O emissions and the population for the Hangzhou Region is found, which is due to a combination of increased application of fertilizers and cultivated area.Such a correlation can not be established for the whole Yangtze River Delta region when the data of both urban and rural areas are included. However, when the data from the heavily urbanized areas are excluded, a significant correlation between population and N2O emissions emerges. The results show clearly that both the temporal and the spatial N2O emissions have significant positive relationship with population under traditional farming practice. These results have implications for suitable mitigation options towards a sustainable agriculture and environment in this region.

  15. Regional Integrated Experiments on Air Quality over Pearl River Delta 2004 (PRIDE-PRD2004): Overview

    Science.gov (United States)

    Zhang, Y. H.; Hu, M.; Zhong, L. J.; Wiedensohler, A.; Liu, S. C.; Andreae, M. O.; Wang, W.; Fan, S. J.

    The aims of the Program of Regional Integrated Experiments on Air Quality over Pearl River Delta of China 2004 (PRIDE-PRD2004) were to characterize in depth the pollution, and to improve the understanding of the chemical and radiative processes in the atmosphere of Pearl River Delta (PRD) in South-Eastern China. This comprehensive program integrated ground-base in situ measurements, vertical observations (including aircraft) and model simulations. The intensive field campaign was conducted from 4 October to 5 November 2004 at two super-sites: an urban site in Guangzhou city (23.13°N, 113.26°E) and a non-urban site at Xinken (22.61°N, 113.59°E). They were coordinated with concurrent meteorological observations as well as measurements at stations of a regional monitoring network. Quality control and quality assurances, application of closure studies and observation-based modeling were the key elements of the research strategies for the PRIDE-PRD2004 campaign. Knowledge and understanding of the important issues, including 3-D distribution of air pollution, ozone formation process and its control strategies, sources of volatile organic compounds, chemical and physical characteristics and radiative properties of aerosols, and the important role of nitrous acid atmospheric chemistry, have been improved substantially by this study.

  16. Transfer of cadmium from soil to vegetable in the Pearl River Delta area, South China.

    Science.gov (United States)

    Zhang, Huihua; Chen, Junjian; Zhu, Li; Yang, Guoyi; Li, Dingqiang

    2014-01-01

    The purpose of this study was to investigate the regional Cadmium (Cd) concentration levels in soils and in leaf vegetables across the Pearl River Delta (PRD) area; and reveal the transfer characteristics of Cadmium (Cd) from soils to leaf vegetable species on a regional scale. 170 paired vegetables and corresponding surface soil samples in the study area were collected for calculating the transfer factors of Cadmium (Cd) from soils to vegetables. This investigation revealed that in the study area Cd concentration in soils was lower (mean value 0.158 mg kg(-1)) compared with other countries or regions. The Cd-contaminated areas are mainly located in west areas of the Pearl River Delta. Cd concentrations in all vegetables were lower than the national standard of Safe vegetables (0.2 mg kg(-1)). 88% of vegetable samples met the standard of No-Polluted vegetables (0.05 mg kg(-1)). The Cd concentration in vegetables was mainly influenced by the interactions of total Cd concentration in soils, soil pH and vegetable species. The fit lines of soil-to-plant transfer factors and total Cd concentration in soils for various vegetable species were best described by the exponential equation (y = ax(b)), and these fit lines can be divided into two parts, including the sharply decrease part with a large error range, and the slowly decrease part with a low error range, according to the gradual increasing of total Cd concentrations in soils.

  17. 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.

  18. Impact of nitrous acid chemistry on air quality modeling results over the Pearl River Delta region

    Directory of Open Access Journals (Sweden)

    R. Zhang

    2011-05-01

    Full Text Available The impact of nitrous acid chemistry on regional ozone and particulate matter in Pearl River Delta region was investigated using the Community Mutilscale Air Quality modeling system and the CB05 mechanism. Model simulations were conducted for a ten-day period in October 2004. Compared with available observed data, the model performance for NOx, SO2, PM10, and sulfate is reasonably good; however, predictions of HONO are an order of magnitude lower than observed data. The CB05 mechanism contains several homogenous reactions related to nitrous acid. To improve the model performance for nitrous acid, direct emissions, two heterogeneous reactions, and two surface photolysis reactions were incorporated into the model. The inclusion of the additional formation pathways significantly improved simulated nitrous acid compared with observed data. The addition of nitrous acid sources enhance daily maximum 8-h ozone by up to 6 ppb V (8 % and daily mean PM2.5 by up to 17 μg m−3 (12 %. They also affected ozone control strategy in Pearl River Delta region.

  19. Magnetic properties of sediments from the Pearl River Delta,South China:Paleoenvironmental implications

    Institute of Scientific and Technical Information of China (English)

    Rodney; GRAPES

    2008-01-01

    Magnetic parameters and their environmental implications of sediments in a core (PD) from the Pearl River Delta, South China, indicate that ferrimagnetic minerals with low coercivity, such as magnetite, dominate the magnetic properties although small amounts of Fe-sulphides occur. The fraction of Fe-sulphides increases and becomes the dominant minerals determining the magnetic characteristics in grey-black organic-rich clay horizons, indicating an anoxic, sulphate-reducing swamp environment resulting from a marine regression. In the "Huaban clay" , hard magnetic minerals, such as hematite and goethite, largely control the magnetic properties of the sediments and imply a long period of exposure and weathering. Where magnetite is the main magnetic mineral, its fraction and grain size determine properties such as magnetic susceptibility (κ ) and saturation isothermal remanent magnetization (SIRM). Ratios of SIRM/κ and χarm/SIRM reflect changes in sea level with high SIRM/κ and χarm/SIRM correlating with a smaller magnetic mineral grain size and rising sea level. Based on downcore variations of these environmental magnetic parameters along with sediment characteristics and microfauna, the sedimentary environment of the Pearl River Delta area can be divided into two main cycles of transgression and regression during the late Pleistocene and Holocene with more sub-cycles of sea level fluctuation during each transgression.

  20. Characteristics and Causes of the Preconsolidation Stress of Soils in the Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    YANG Xiujuan; JIA Yonggang; LIU Hongjun; SHAN Hongxian

    2009-01-01

    Preconsolidation stress ( σ'P ) is the maximum effective stress that a soil has suffered throughout its life. From a geotechnical point of view, pre-consolidation stress has great importance because it separates elastic and reversible deformations from inelastic and only partially irreversible deformations and marks the starting point of high compressibility. In this study we calculated the preconsolidation stress for 72 undisturbed soil samples from the Yellow River Delta, using the oedometer test and applying the method proposed by Casagrande. The results showed that the over-consolidation ratio (OCR-the ratio of pre-consolidation stress to current natural overburden stress) values of the soil from soil surface to 6m depth varied from 1.72 to 15.34 and the maximum preconsolidation stress was above 200kPa. In consequence, the soils of the Yellow River Delta are highly over-consolidated within the upper 6m, the OCR decreasing gradually with depth from 6 to 12m. For samples from deeper than 12m the soils were found to be under-consolidated, which was proved by standard penetration tests (SPTs). The main causes of this type of consolidation are the mineral composition and the designability of the soil body.

  1. Urban Household Carbon Emission and Contributing Factors in the Yangtze River Delta, China

    Science.gov (United States)

    Xu, Xibao; Tan, Yan; Chen, Shuang; Yang, Guishan; Su, Weizhong

    2015-01-01

    Carbon reduction at the household level is an integral part of carbon mitigation. This study analyses the characteristics, effects, contributing factors and policies for urban household carbon emissions in the Yangtze River Delta of China. Primary data was collected through structured questionnaire surveys in three cities in the region – Nanjing, Ningbo, and Changzhou in 2011. The survey data was first used to estimate the magnitude of household carbon emissions in different urban contexts. It then examined how, and to what extent, each set of demographic, economic, behavioral/cognitive and spatial factors influence carbon emissions at the household level. The average of urban household carbon emissions in the region was estimated to be 5.96 tonnes CO2 in 2010. Energy consumption, daily commuting, garbage disposal and long-distance travel accounted for 51.2%, 21.3%, 16.0% and 11.5% of the total emission, respectively. Regulating rapidly growing car-holdings of urban households, stabilizing population growth, and transiting residents’ low-carbon awareness to household behavior in energy saving and other spheres of consumption in the context of rapid population aging and the growing middle income class are suggested as critical measures for carbon mitigation among urban households in the Yangtze River Delta. PMID:25884853

  2. Urban household carbon emission and contributing factors in the Yangtze River Delta, China.

    Directory of Open Access Journals (Sweden)

    Xibao Xu

    Full Text Available Carbon reduction at the household level is an integral part of carbon mitigation. This study analyses the characteristics, effects, contributing factors and policies for urban household carbon emissions in the Yangtze River Delta of China. Primary data was collected through structured questionnaire surveys in three cities in the region--Nanjing, Ningbo, and Changzhou in 2011. The survey data was first used to estimate the magnitude of household carbon emissions in different urban contexts. It then examined how, and to what extent, each set of demographic, economic, behavioral/cognitive and spatial factors influence carbon emissions at the household level. The average of urban household carbon emissions in the region was estimated to be 5.96 tonnes CO2 in 2010. Energy consumption, daily commuting, garbage disposal and long-distance travel accounted for 51.2%, 21.3%, 16.0% and 11.5% of the total emission, respectively. Regulating rapidly growing car-holdings of urban households, stabilizing population growth, and transiting residents' low-carbon awareness to household behavior in energy saving and other spheres of consumption in the context of rapid population aging and the growing middle income class are suggested as critical measures for carbon mitigation among urban households in the Yangtze River Delta.

  3. Analysis the Opportunities and Challenges of Pearl River Delta Economy in China

    Institute of Scientific and Technical Information of China (English)

    陈铁双

    2014-01-01

    This paper examines the strategies of Chinese government policies to develop of Pearl River Delta (PRD) in the coming decades. Through analyzing the opportunities and chal enges of the Macro-environment of the PRD, I wil il ustrate the competition to be an investment basement from inside and outside of the country as wel as the supportive government policies. In the past three decades, the original core competences of PRD such as low labor cost, broad foreign investment policies and the even cheap transportation is losing its at ractiveness compared to the Yangtze River Delta (YRD). This paper also il ustrated the polices which support PRD economic transformation and Hong Kong as an international trade hub city that wil play a key role in enhancing the speed of the transformation. The expectation of this research is that PRD wil present itself as a new economic zone in the world, develop value-added, high-tech manufacturing, brand innovated, and environment friendly industries. A new outlook of PRD is emerging in front of the world.

  4. Transfer of cadmium from soil to vegetable in the Pearl River Delta area, South China.

    Directory of Open Access Journals (Sweden)

    Huihua Zhang

    Full Text Available The purpose of this study was to investigate the regional Cadmium (Cd concentration levels in soils and in leaf vegetables across the Pearl River Delta (PRD area; and reveal the transfer characteristics of Cadmium (Cd from soils to leaf vegetable species on a regional scale. 170 paired vegetables and corresponding surface soil samples in the study area were collected for calculating the transfer factors of Cadmium (Cd from soils to vegetables. This investigation revealed that in the study area Cd concentration in soils was lower (mean value 0.158 mg kg(-1 compared with other countries or regions. The Cd-contaminated areas are mainly located in west areas of the Pearl River Delta. Cd concentrations in all vegetables were lower than the national standard of Safe vegetables (0.2 mg kg(-1. 88% of vegetable samples met the standard of No-Polluted vegetables (0.05 mg kg(-1. The Cd concentration in vegetables was mainly influenced by the interactions of total Cd concentration in soils, soil pH and vegetable species. The fit lines of soil-to-plant transfer factors and total Cd concentration in soils for various vegetable species were best described by the exponential equation (y = ax(b, and these fit lines can be divided into two parts, including the sharply decrease part with a large error range, and the slowly decrease part with a low error range, according to the gradual increasing of total Cd concentrations in soils.

  5. Magnetic properties of sediments from the Pearl River Delta, South China: Paleoenvironmental implications

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Magnetic parameters and their environmental implications of sediments in a core (PD) from the Pearl River Delta, South China, indicate that ferrimagnetic minerals with low coercivity, such as magnetite, dominate the magnetic properties although small amounts of Fe-sulphides occur. The fraction of Fe-sulphides increases and becomes the dominant minerals determining the magnetic characteristics in grey-black organic-rich clay horizons, indicating an anoxic, sulphate-reducing swamp environment resulting from a marine regression. In the "Huaban clay", hard magnetic minerals, such as hematite and goethite, largely control the magnetic properties of the sediments and imply a long period of exposure and weathering. Where magnetite is the main magnetic mineral, its fraction and grain size determine properties such as magnetic susceptibility (κ) and saturation isothermal remanent magnetization (SIRM). Ratios of SIRM/κ and χarm/SIRM reflect changes in sea level with high SIRM/κ and χarm/SIRM correlating with a smaller magnetic mineral grain size and rising sea level. Based on downcore variations of these environmental magnetic parameters along with sediment characteristics and microfauna, the sedimentary environment of the Pearl River Delta area can be divided into two main cycles of transgression and regression during the late Pleistocene and Holocene with more sub-cycles of sea level fluctuation during each transgression.

  6. On temporal evolution of precipitation probability of the Yangtze River delta in the last 50 years

    Science.gov (United States)

    Feng, Guo-Lin; Dong, Wen-Jie; Li, Jing-Ping

    2004-09-01

    The monthly precipitation observational data of the Yangtze River delta are transformed into the temporal evolution of precipitation probability (PP) and its hierarchically distributive characters have been revealed in this paper. Research results show that precipitation of the Yangtze River delta displays the interannual and interdecadal characters and the periods are all significant at a confidence level of more than 0.05. The interdecadal is an important time scale, because it is on the one hand a disturbance of long period changes and on the other hand it is also the background for interannual change. The interdecadal and 3-7y oscillations have different motion laws in the data-based mechanism self-memory model (DAMSM). Meanwhile, this paper also provides a new train of thought for dynamic modelling. Because this method only involves a certain length of data series, it can be used in many fields, such as meteorology, hydrology, seismology and economy etc and thus has a bright perspective in practical applications.

  7. On temporal evolution of precipitation probability of the Yangtze River delta in the last 50 years

    Institute of Scientific and Technical Information of China (English)

    Feng Guo-Lin; Dong Wen-Jie; Li Jing-Ping

    2004-01-01

    The monthly precipitation observational data of the Yangtze River delta are transformed into the temporal evolution of precipitation probability (PP), and its hierarchically distributive characters have been revealed in this paper.Research results show that precipitation of the Yangtze River delta displays the interannual and interdecadal characters and the periods are all significant at a confidence level of more than 0.05. The interdecadM is an important time scale,because it is on the one hand a disturbance of long period changes, and on the other hand it is also the background for interannual change. The interdecadal and 3-7y oscillations have different motion laws in the data-based mechanism self-memory model (DAMSM). Meanwhile, this paper also provides a new train of thought for dynamic modelling.Because this method only involves a certain length of data series, it can be used in many fields, such as meteorology,hydrology, seismology, and economy etc, and thus has a bright perspective in practical applications.

  8. A methodological approach to rapid assessment of a river flood in coastal waters. First test in the Po River delta

    Science.gov (United States)

    Campanelli, Alessandra; Bellafiore, Debora; Bensi, Manuel; Bignami, Francesco; Caccamo, Giuseppe; Celussi, Mauro; Del Negro, Paola; Ferrarin, Christian; Marini, Mauro; Paschini, Elio; Zaggia, Luca

    2014-05-01

    As part of the actions of the flagship project RITMARE (Ricerca ITaliana per il MARE) a daily oceanographic survey was performed on 29th November 2013 in front of the Po River delta (Northern Adriatic Sea). The Po river affects a large part of the Northern Adriatic Sea with strong implications on the circulation and functionality of the basin. Physical-chemical and biological properties of coastal waters were investigated after a moderate flood occurred around 25th-27th November. The cruise activities, carried out using a small research boat, were mainly focused on the test of a methodological approach to investigate the environment variability after a flood event in the framework of rapid assessment. The effects of the flood on the coastal waters, have been evaluated in the field using operational forecasts and real-time satellite imagery to assist field measurements and samplings. Surface satellite chlorophyll maps and surface salinity and current maps obtained from a numerical model forced by meteorological forecast and river data were analyzed to better identify the Po plume dispersion during and after the event in order to better locate offshore monitoring stations at the sea. Profiles of Temperature, Salinity, Turbidity, Fluorescence and Colored Dissolved Organic Matter (CDOM) throughout the water column were collected at 7 stations in front of the Po River delta. Sea surface water samples were also collected for the analysis of nutrients, Dissolved Organic Carbon (DOC) and CDOM (surface and bottom). The CDOM regulates the penetration of UV light throughout the water column and mediates photochemical reactions, playing an important role in many marine biogeochemical processes. Satellite images showed a strong color front that separates the higher-chlorophyll coastal water from the more oligotrophic mid-basin and eastern boundary Adriatic waters. In front of the river mouth, the surface layer was characterized by low salinity (14-15), high turbidity (8-11 NTU

  9. [Shifting path of industrial pollution gravity centers and its driving mechanism in Pan-Yangtze River Delta].

    Science.gov (United States)

    Zhao, Hai-Xia; Jiang, Xiao-Wei; Cui, Jian-Xin

    2014-11-01

    Shifting path of industrial pollution gravity centers is the response of environmental special formation during the industry transfer process, in order to prove the responding of industrial pollution gravity centers to industry transfer in economically developed areas, this paper calculates the gravity centers of industrial wastewater, gas and solid patterns and reveals the shifting path and its driving mechanism, using the data of industrial pollution in the Pan-Yangtze River Delta from 2000 to 2010. The results show that the gravity center of the industrial waste in Pan-Yangtze River Delta shifts for sure in the last 10 years, and gravity center of solid waste shifts the maximum distance within the three wastes, which was 180.18 km, and shifting distances for waste gas and waste water were 109.51 km and 85.92 km respectively. Moreover, the gravity center of the industrial waste in Pan-Yangtze River Delta shifts westwards, and gravity centers of waste water, gas and solid shift for 0.40 degrees, 0.17 degrees and 0.03 degrees respectively. The shifting of industrial pollution gravity centers is driven by many factors. The rapid development of the heavy industry in Anhui and Jiangxi provinces results in the westward shifting of the pollutions. The optimization and adjustment of industrial structures in Yangtze River Delta region benefit to alleviating industrial pollution, and high-polluting industries shifted to Anhui and Jiangxi provinces promotes pollution gravity center shifting to west. While the development of massive clean enterprise, strong environmental management efforts and better environmental monitoring system slow the shifting trend of industrial pollution to the east in Yangtze River Delta. The study of industrial pollution gravity shift and its driving mechanism provides a new angle of view to analyze the relationship between economic development and environmental pollution, and also provides academic basis for synthetical management and control of

  10. REE systematics in modern bottom sediments of the Caspian Sea and river deltas worldwide: Experience of comparison

    Science.gov (United States)

    Maslov, A. V.; Kozina, N. V.; Shevchenko, V. P.; Klyuvitkin, A. A.; Sapozhnikov, Ph. V.; Zavialov, P. O.

    2017-07-01

    The results of comparison of a number of main parameters of the chondrite-normalized REE distribution spectra in modern bottom, mainly pelitic, sediments of various sedimentary subsystems of the Caspian Sea and marginal filters of the Volga and Ural rivers with those characteristic of the pelitic fraction of modern bottom sediments of different river deltas worldwide are discussed. According to the features of the REE distribution spectra, as well as the ɛNd(0) values, it has been established that most samples of the Caspian bottom sediments are similar to those of large rivers and rivers, draining watersheds composed of sedimentary formations.

  11. Cryosols of the Northeast Siberian Lena River Delta and its hinterland - genesis and diversity

    Science.gov (United States)

    Zubrzycki, Sebastian; Kutzbach, Lars; Pfeiffer, Eva-Maria

    2016-04-01

    The North-Siberian Lena River Delta (LRD) is the largest Arctic delta and an important interface between the Arctic Ocean in the North and the large Siberian land masses in the South. LRD consists not only of Holocene deltaic sediment deposits as a river terrace and the modern active floodplains but also of remnants of the former Pleistocene mainland including large islands of ice-complex sediments and the Arga-Muora-Sise Island, which is composed of pure sand sediments of still debated origin. The highly diverse landscape structure of LRD is reflected by a great variety of permafrost-affected soils (cryosols). This study aims at describing this great cryosol diversity and at analysing the dominant soil-forming processes in this comparatively scarcely studied soil region. The soil development in the investigated continuous permafrost region is limited by the short thawing period of around three months (June to September) and takes place in the shallow (below 1 m) seasonally thawed active layer. The geological parent material plays an important role for the development of soils in the LRD region. The distribution of the various soil types closely follows the pattern of the geomorphic units characterised by differing sedimentation conditions. The properties and genesis of the soils on the Holocene river terrace and the modern floodplains are strongly affected by the enormous amounts of fluvial sediments (about 12 x 106 tons per year) brought by the Lena River into its delta. The fluvial sedimentation together with the also pronounced aeolian sedimentation results in a fast vertical growth of soils. The upward rise of the soil surface leads to an upward movement of the permafrost table resulting in fast incorporation of soil material formed in the supra-permafrost zone into the permafrost. Due to the morphodynamics of ice-wedge polygons and resulting formation of patterned ground with elevated rims and depressed and water-saturated centres, the Holocene river terrace

  12. The Lena River Delta Observatory, Arctic Siberia: a Contribution to the ESA DUE Permafrost Project

    Science.gov (United States)

    Heim, Birgit; Boike, Julia; Moritz, Langer; Annett, Bartsch; Sina, Muster; Jennifer, Sobiech; Konstanze, Piel; Günter, Stoof; Anne, Morgenstern; Mathias, Ulrich

    2010-05-01

    The major task of the ESA Data User Element DUE PERMAFROST is to develop and use Earth Observation services specifically for monitoring and modelling of permafrost. In order to setup the required information services, a target area approach with specified case study regions is used. Long-term ground data series and multidisciplinary ongoing projects make the Lena River delta (Arctic Siberia) a prime study region for evaluation and validation of the DUE PERMAFROST remote sensing products. The Lena River Delta located in the zone of continuous permafrost is a key region for Arctic system science. Since 1998, the Alfred Wegener Institute for Polar and Marine Research AWI in collaboration with the Lena Delta Reserve in Tiksi has operated the German-Russian research station Samoylov. Relevant ground-based data (air temperature, radiation, snow, albedo, soil temperature and moisture) are collected continuously. The high landscape heterogeneity (wet polygonal centres, dry polygonal rims, ponds and lakes) challenges all ground data observations. Match-up data sets of ground data and remote sensing products coincident in time and location are being built up. Exclusion and selection criteria will be based on experience, especially the knowledge on parameter variability in time and space. The main focus are the remote sensing products ‘surface temperature', ‘surface moisture', ‘albedo', ‘vegetation' and ‘water'. Statistical and contextural methods will be used for the upscaling from the plot to the meso-scale. Problems will have to be identified such as process-dependent scales and the water body ratio within the pixel.

  13. Tidal flat erosion of the Huanghe River Delta due to local changes in hydrodynamic conditions

    Institute of Scientific and Technical Information of China (English)

    JIA Yonggang; ZHENG Jiewen; YUE Zhongqi; LIU Xiaolei; SHAN Hongxian

    2014-01-01

    An ideal nature system for the study of post-depositional submarine mass changing under wave loading was selected in the inter-tidal platform of the subaqueous Huanghe River Delta, a delta formed during pe-riod from 1964 to 1976 as the Huanghe River discharged into the Bohai Gulf by Diaokou distributary. A road embankment constructed for petroleum recovery on the inter-tidal platform in 1995 induced the essential varieties of hydrodynamic conditions on the both sides of the road. With both sides sharing similarities in (1) initial sedimentary environment, (2) energetic wave loading, (3) differential hydrodynamic conditions in later stages, (4) enough long-range action, and (5) extreme shallow water inter-tidal platforms;the study is representative and feasible as well. Two study sites were selected on each side of the road, and a series of measurements, samplings, laboratory experiments have been carried out, including morphometry, hydro-dynamic conditions, sediment properties, granularity composition, and fractal dimension calculation of the topography in the two adjacent areas. It was observed that in the outer zone, where wave loading with high magnitude prevailed, the tidal flat was bumpy and exhibited a high erosion rate and high fractal dimension. Further, the fractal dimension diminished quickly, keeping with the enlarging of calculative square size. However in the inner zone, where the hydrodynamic condition was weak, the tidal flat was flat and exhibited a low erosion rate and low fractal dimensions;the fractal dimension diminished with the enlarging of calcu-lative square size. The fractal dimensions in the different hydrodynamic areas equalized increasingly as the calculative square size accreted to threshold, indicating that the hydrodynamic condition plays a significant role in topography construction and submarine delta erosion process. Additionally, the later differentiation of sediment properties, granularity composition, microstructure

  14. Observational and numerical particle tracking to examine sediment dynamics in a Mississippi River delta diversion

    Science.gov (United States)

    Allison, Mead A.; Yuill, Brendan T.; Meselhe, Ehab A.; Marsh, Jonathan K.; Kolker, Alexander S.; Ameen, Alexander D.

    2017-07-01

    River diversions may serve as useful restoration tools along coastal deltas experiencing land loss due to high rates of relative sea-level rise and the disruption of natural sediment supply. Diversions mitigate land loss by serving as new sediment sources for land building areas in basins proximal to river channels. However, because of the paucity of active diversions, little is known about how diversion receiving-basins evacuate or retain the sediment required to build new land. This study uses observational and numerical particle tracking to investigate the behavior of riverine sand and silt as it enters and passes through the West Bay diversion receiving-basin located on the lowermost Mississippi River delta, USA. Fluorescent sediment tracer was deployed and tracked within the bed sediment over a five-month period to identify locations of sediment deposition in the receiving-basin and nearby river channel. A computational fluid dynamics model with a Lagrangian sediment transport module was employed to predict selective pathways for riverine flow and sand and silt particles through the receiving-basin. Observations of the fluorescent tracer provides snapshots of the integrated sediment response to the full range of drivers in the natural system; the numerical model results offer a continuous map of sediment advection vectors through the receiving basin in response to river-generated currents. Together, these methods provide insight into local and basin-wide values of sediment retention as influenced by grain size, transport time, and basin morphology. Results show that after two weeks of low Mississippi River discharge, basin silt retention was approximately 60% but was reduced to 4% at the conclusion of the study. Riverine sand retention was approximately near 100% at two weeks and 40% over the study period. Modeled sediment storage was predicted to be greatest at the margins of the primary basin transport pathway; this matched the observed dynamics of the silt

  15. Decoupled Changes in Western Niger Delta Primary Productivity and Niger River Discharge Across the Last Deglacial

    Science.gov (United States)

    Parker, A. O.; Schmidt, M. W.; Slowey, N. C.; Jobe, Z. R.; Marcantonio, F.

    2014-12-01

    Abrupt droughts in West Africa impart significant socio-economic impacts on the developing countries of this region, and yet a comprehensive understanding of the causes and duration of such droughts remains elusive. Much of the summertime rainfall associated with the West African Monsoon (WAM) falls within the Niger River basin and eventually drains into the eastern Gulf of Guinea, contributing to the low sea-surface salinity of this region. Of the limited number of studies that reconstruct Gulf of Guinea salinity through the deglacial, the most comprehensive of those is located ~ 400 km east of the Niger delta and may not be solely influenced by WAM runoff. Here, we present XRF and foraminiferal trace metal data from two new cores located less than 100 km from the Western Niger Delta. Radiocarbon dating of cores Grand 21 (4.72oN, 4.48oE) and Fan 17 (4.81oN, 4.41oE) produced near linear sedimentation rates of 20 cm/kyr and 15 cm/kyr respectively. Elemental sediment compositions from XRF core scanning reveal an abrupt 50% increase in SiO2 between 17-15 ka during Heinrich Event 1. This increase, coeval with increases of CaCO3 (+12%) content and Ba/Ti ratios suggests a large increase in primary productivity during H1. Values then decrease at the onset of the Bolling-Allerod (~14.6 kyr) until a similar, albeit smaller increase is recorded during the Younger Dryas beginning at 12.7 kyr. In contrast, FeO2 and TiO2 are thought to be a proxies of Niger River discharge strength and suggest a more gradual change in riverine discharge across the deglacial that is most likely driven by precession. These proxies suggest Niger River runoff was low from the LGM through Heinrich 1, gradually increasing around 13 ka. FeO2 and TiO2 values then peak between 11.5-7.5 kyr, consistent with the African Humid Period, before gradually decreasing through the mid-late Holocene. This deglacial pattern of riverine input is markedly different from previous reconstructions of WAM variability and

  16. Enhancing mud supply from the Lower Missouri River to the Mississippi River Delta USA: Dam bypassing and coastal restoration

    Science.gov (United States)

    Kemp, G. Paul; Day, John W.; Rogers, J. David; Giosan, Liviu; Peyronnin, Natalie

    2016-12-01

    Sand transport to the Mississippi River Delta (MRD) remains sufficient to build wetlands in shallow, sheltered coastal bays fed by engineered diversions on the Mississippi River (MR) and its Atchafalaya River (AR) distributary. But suspended mud (silt & clay) flux to the coast has dropped from a mean of 390 Mt y-1 in the early 1950s, to 100 Mt y-1 since 1970. This fine-grained sediment travels deeper into receiving estuarine basins and plays a critical role in sustaining existing marshes. Virtually all of the 300 Mt y-1 of missing mud once flowed from the Missouri River (MOR) Basin before nearly 100 dams were built as part of the Pick-Sloan water development project. About 100 Mt y-1 is now intercepted by main-stem Upper MOR dams closed in 1953. But the remaining 200 Mt y-1 is trapped by impoundments built on tributaries to the Lower MOR in the 1950s and 1960s. Sediment flux during the post-dam high MOR discharge years of 1973, 1993 and 2011 approached pre-dam levels when tributaries to the Lower MOR, including the Platte and Kansas Rivers, contributed to flood flows. West bank tributaries drain a vast, arid part of the Great Plains, while those entering from the east bank traverse the lowlands of the MOR floodplain. Both provinces are dominated by highly erodible loess soils. Staunching the continued decline in MR fine-grained sediment flux has assumed greater importance now that engineered diversions are being built to reconnect the Lowermost MR to the MRD. Tributary dam bypassing in the Lower MOR basin could increase mud supply to the MRD by 100-200 Mt y-1 within 1-2 decades. Such emergency measures to save the MRD are compatible with objectives of the Missouri River Restoration and Platte River Recovery Programs to restore MOR riparian habitat for endangered species. Rapid mobilization to shunt fine-grained sediments past as many as 50 Lower MOR tributary dams in several U.S. states will undoubtedly require as much regional coordination and funding in the 21st

  17. Sustainable Growth in Urbanised Delta Areas: the Opportunities of a Geographical Approach to the Pearl River Delta

    NARCIS (Netherlands)

    Van Rens, G.; Nillisen, A.L.; Schamhart, C.; Lugt, N.

    2006-01-01

    The attractions of delta areas have boomed economies and founded major cities, but the threats of the adjacent water have persisted and natural resources have declined. The objective to facilitate sustainable urban growth in delta areas can only be met by a simultaneous approach of all the stakehold

  18. Temporal and spatial evolution of coastline and subaqueous geomorphology in muddy coast of the Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    PENG Jun; MA Suisui; CHEN Hongquan; LI Zhiwen

    2013-01-01

    Based on measured data of coastline and bathometry,processed by softwares of Surfer and Mapinfo,and combined with sediment loads in different phases at Lijin gauging station,temporal and spatial evolution of coastline and subaqueous geomorphology in muddy coast of the Yellow River Delta is analyzed.The results show that ~68% of sediments were delivered by the Yellow River deposited around the river mouth and in the littoral area from 1953 to 2000.Coastline in different coasts had distinctive changes in response to shifts of river course.Coastline was stable in the west of the Diaokou river mouth.Coastline from the east of the Diaokou river mouth to the north of the Gudong oilfield had experienced siltation,then serious erosion,and finally kept stable with sea walls conservation.Generally,coastline of the survived river mouth of the Qingshuigou river course stretched seaward,whereas the south side of sand spit at the Qingshuigou old river mouth was eroded after the Yellow River inpouring near the position at the Qing 8.The subaqueous geomorphology off the survived river mouth exhibited siltation from 1976 to 1996,with flat topset beds and steeper foreset beds.From 1996 to 2005,the subaqueous geomorphology off the Qingshuigou old river mouth was eroded in the topset and foreset beds,but silted in the bottomset beds.The subaqueous geomorphology off the new river mouth sequentially performed siltation with small degree compared to that of 1976-1996.

  19. FUZZY COMPREHENSIVE EVALUATION OF CONTAINER TRANSPORTATION MODES ALONG THE CHANGJIANG RIVER MAIN LINE AND ITS DELTA AREA

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shi-yu; XIAO Han-liang

    2003-01-01

    The Changjiang River (Yangtze) is one of the fastest growth areas of container transportation in Chi-na. Rail, road and water transportation have competed against each other for container transportation in the Chang-jiang River main line and its delta area. It is of significance to assess these different transportation modes scientifi-cally in order to organize container transportation efficiently in this area and make decision for integral plan and construction of transportation system in this area. This paper outlines application of fuzzy comprehensive evaluation to appraise different modes of typical direction of containers. Twelve assessment indexes were decided. Membership functions were formulated. Evaluation results indicated that road transportation was optimal mode in the Changjiang River delta area, however water transportation was the primary way in the Changjiang River main line.

  20. Evolution of the Yellow River Delta and its relationship with runoff and sediment load from 1983 to 2011

    Science.gov (United States)

    Kong, Dongxian; Miao, Chiyuan; Borthwick, Alistair G. L.; Duan, Qingyun; Liu, Hao; Sun, Qiaohong; Ye, Aizhong; Di, Zhenhua; Gong, Wei

    2015-01-01

    Long-term data from a hydrological monitoring station and remotely-sensed satellite images were used to explore the effects of runoff and suspended sediment load on evolution of the Yellow River Delta (YRD) from 1983 to 2011. During this period, an average runoff of 18 × 109 m3 yr-1 and an average sediment load of 341 × 106 t yr-1 flowed through the delta lobes into the sea. The runoff and sediment load exhibited downward trends with time, along with large inter-annual fluctuations. Three stages were evident in the data. From 1983 to the late 1990s, the Yellow River experienced progressively severe droughts which reduced both runoff and sediment load to its delta lobe. The delta nevertheless grew to a peak area of about 3950 km2 in 2000. From 2000 to 2003, the YRD area decreased. Meanwhile, the operation of the dam at Xiaolangdi and changes in water consumption driven by a new regulatory framework helped stabilize the runoff. Although the sediment load continued to decline, partly due to sediment check dams along the middle Yellow River and the reduced sediment carrying capacity of the river, the YRD area nevertheless increased between 2003 and 2011. The variations in runoff and sediment load directly influenced changes to the plan-form area, shoreline migration, and morphology of the YRD. From 1983 to 2011, the net land area of the delta increased by 248 km2, its coastline extended by 36.45 km, and its shape became increasingly irregular due to the emergence of its delta lobes. In 1996, an artificial diversion altered the position of the main delta lobe from Qingshuigou to Qing 8. A stepwise multiple regression analysis indicated that the YRD would have required average sediment loads of about 441 × 106 t yr-1 before 1996 and 159 × 106 t yr-1 after 1996 to maintain equilibrium.

  1. Heavy metals in oysters, mussels and clams collected from coastal sites along the Pearl River Delta, South China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Concentrations of 8 heavy metals: cadmium (Cd), copper(Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), antimony(Sb) and tin (Sn) were examined in 3 species of bivalves (Pernaviridis, Crassostrea rivularis and Ruditapes philippinarum)collected from 25 sites along the Pearl River Delta coastal watersin the South China Sea from July to August 1996. In general, Cd,Cu, Zn and Sn concentrations in the three bivalve species collectedfrom the Estuarine Zone were significantly higher than thosecollected from the Western and Eastern Zones of the Pearl RiverDelta, which are related to the existence of various anthropogenicactivities in the catchment of the Pearl River Delta. The WesternEstuarine Zone is mainly impacted by Cr, Ni and Cu contamination.In Victoria Harbor, heavy metal contamination is mainly due to Cuand Pb. Cd, Cu and Zn concentrations in oysters were significantlyhigher than those in mussels and clams. This could be explained bythe fact that oysters live mainly in the Estuarine Zone of thePearl River Delta which receives most of the polluting dischargesfrom the catchment of the Delta. During turbid condition, heavymetals (soluble or adsorbed on suspended particulates) dischargedfrom the Delta are filtered from the water column and subsequentlyaccumulated into the soft body tissues of oysters. Heavy metalconcentrations in the three bivalve species were compared with themaximum permissible levels of heavy metals in seafood regulated bythe Public Health and Municipal Services Ordinance, Laws of HongKong, and it was revealed that Cd and Cr concentrations in thethree bivalve species exceeded the upper limits. At certainhotspots in the Delta, the maximum acceptable daily load for Cd wasalso exceeded.

  2. River Network Uncertainty and Coastal Morphodynamics in the Mekong Delta: Model Validation and Sensitivity to Fluvial Fluxes

    Science.gov (United States)

    Tessler, Z. D.; Vorosmarty, C. J.; Cohen, S.; Tang, H.

    2014-12-01

    A loose-coupling of a basin-scale hydrological and sediment flux model with acoastal ocean hydrodynamics model is used to assess the importance ofuncertainties in river mouth locations and fluxes on coastal geomorphology ofthe Mekong river delta. At the land-ocean interface, river deltas mediate theflux of water, sediment, and nutrients from the basin watershed, though thecomplex delta river network, and into the coastal ocean. In the Mekong riverdelta, irrigation networks and surface water storage for rice cultivationredistribute, in space and time, water and sediment fluxes along the coastline.Distribution of fluxes through the delta is important for accurate assessment ofdelta land aggregation, coastline migration, and coastal ocean biogeochemistry.Using a basin-scale hydrological model, WBMsed, interfaced with a coastalhydrodynamics/wave/sediment model, COAWST, we investigate freshwater andsediment plumes and morphological changes to the subaqueous delta front. Thereis considerable uncertainty regarding how the delta spatially filters water andsediment fluxes as they transit through the river and irrigation network. Byadjusting the placement and relative distribution of WBMsed discharge along thecoast, we estimate the resulting bounds on sediment plume structure, timing, andmorphological deposition patterns. The coastal ocean model is validated bycomparing simulated plume structure and seasonality to MERIS and MODIS derivedestimates of surface turbidity. We find good agreement with regards to plumeextent and timing, with plumes weakest in the early spring, extending stronglyto the west in the fall, and toward the east in winter. Uncertainty regardingriver outflow distribution along the coastline leads to substantial uncertaintyin rates of morphological change, particularly away from the main Mekong Riverdistributary channels.

  3. Georelational analysis of soil type, soil salt content, landform, and land use in the Yellow River Delta, China.

    Science.gov (United States)

    Fang, Hongliang; Liu, Gaohuan; Kearney, Michael

    2005-01-01

    The Yellow River Delta, one of China's three major river deltas, is becoming a major region for the development of agriculture and fisheries. Protecting the delicate ecology of newly formed aquatic systems as well as the evolution of soils, natural vegetation, and fauna on older upland environments in the delta is a priority in planning for the wise use of the delta's resources for future agricultural development. In this article, we use a Geographic Information System (GIS) to analyze relationships between land-use/ land-cover characteristics in the Dongying municipality, one of the most intensely developed areas of the delta, and spatial variations in soil salinity and landforms. This analysis reveals that soil salt content decreases from regionally high values in isolated depressions to relatively moderate values in embanked former back swamps, with the lowest values occurring in abandoned river courses. Comparing the present land use on this soil salinity-landform pattern shows that it is basically at odds with general concepts of land suitability for agricultural utilization of saline soils. Crop-based agriculture in the region is probably overdeveloped, whereas more appropriate agricultural development, like cattle and forest production, is underrepresented. Future development should focus on converting farmland in embanked former back swamps and abandoned river courses into grasslands and forests. Crop-based agriculture (up to 151,000 ha) could be planned at the low-salinity terrace uplands and flood plains. The article provides guidelines for decision-makers regarding agricultural land use and wetland protection in the Yellow River Delta.

  4. 2010-2015 Juvenile fish ecology in the Nisqually River Delta and Nisqually Reach Aquatic Reserve

    Science.gov (United States)

    Hodgson, Sayre; Ellings, Christopher S.; Rubin, Steve P.; Hayes, Michael C.; Duval, Walker; Grossman, Eric E.

    2017-01-01

    The return of tidal inundation to over 750 acres of the U. S. Fish and Wildlife Service Billy Frank Jr. Nisqually National Wildlife Refuge (NNWR) in fall of 2009 was the crowning moment in the effort to protect and restore the Nisqually Delta. The Nisqually NWR project complemented three earlier restoration projects completed by the Nisqually Indian Tribe (Tribe) on tribal property to restore over 900 acres of the estuary, representing the largest estuary restoration project in the Pacific Northwest and one of the most significant advances to date towards the recovery of Puget Sound (USFWS 2005). In 2011 the Washington Department of Natural Resources (WADNR established the over 14000 acre Nisqually Reach Aquatic Reserve (Reserve), complementing the protection and restoration successes in the Nisqually Delta. The Reserve includes all state-owned aquatic lands around Anderson, Ketron and Eagle islands and part of McNeil Island (Figure 1, WDNR 2011). The Reserve also includes a diverse assemblage of nearshore and offshore habitats important to resident and migratory fish including federal endangered species act listed fish like Chinook salmon (Oncorynchus tshawytscha) and steelhead (O. mykiss). Studies in the Nisqually Estuary (Ellings and Hodgson 2007, David et al. 2014, Ellings et al. 2016) and South Puget Sound (Duffy 2003) have summarized fish use of the area. However, the fish ecology of the reserve had not been systematically surveyed. The Tribe, U.S. Geological Survey (USGS), NNWR, Nisqually River Foundation (NRF), and others are currently conducting a multi-year, interdisciplinary, hypothesis-based research and monitoring study investigating the impact of delta restoration on estuarine processes, habitat structures, and functions. Our interdisciplinary monitoring framework enables us to link key estuarine processes with habitat development and biological response at multiple scales across the restored footprint, reference marshes, and throughout the Nisqually

  5. Greenhouse gas emissions of different land uses in the delta region of Red River, Vietnam

    Science.gov (United States)

    Zhou, Minghua; Ha, Thu; An, Ngo The; Brüggemann, Nicolas

    2017-04-01

    Agricultural activities are responsible for up to a third of total anthropogenic GHG emissions. The subtropical/tropical delta areas of the large rivers in Southeast Asia are long-term history agricultural regions in the world. However, due to lack of field measurements, the estimation of the contribution of agro-ecosystems in the subtropical/tropical delta areas to global greenhouse gas emissions remains largely uncertain. Here, we conducted field experiments since January 2016 to quantify greenhouse gases (CO2, CH4 and N2O) emissions from four agricultural land uses of annual rice-rice, rice-vegetable, continuous vegetable system and fish pond in Red River delta region of Vietnam by using the transparent static chamber-gas chromatography technique. Higher N2O emissions were observed in the rice-vegetable and continuous vegetable systems, while lower N2O emissions were observed in the rice-rice and find pond systems. Compared to rice-rice system the cumulative N2O fluxes were on average twenty-fold higher in the rice-vegetable and continuous vegetable systems but significantly lower (75%) in the fish pond. Overall the net CO2 sinks were observed in the rice-rice system while other three land uses of rice-vegetable, continuous vegetable and fish pond acted as the net CO2 sources. The rice-rice and fish pond showed net CH4 emissions while variations of CH4 emissions (i.e. shifting between sources and sinks) along variations of soil moisture and temperature were observed in rice-vegetable and continuous vegetable systems. Compared to rice-rice system, the cumulative CH4 fluxes were significantly decreased by 100% for continuous vegetable system, 94% for rice-vegetable system and 89% for fish pond. Overall, the data suggest that conversion of traditional rice-rice paddy system to rice-vegetable, continuous vegetable system and find pond, which are currently undergoing driven by the economical requests and environmental changes (e.g., salinity intrusion) in this delta

  6. Distribution of organophosphorus flame retardants in sediments from the Pearl River Delta in South China.

    Science.gov (United States)

    Tan, Xiao-Xin; Luo, Xiao-Jun; Zheng, Xiao-Bo; Li, Zong-Rui; Sun, Run-Xia; Mai, Bi-Xian

    2016-02-15

    Twelve organophosphorus flame retardants (PFRs) were identified in the sediments and the sediment core collected from the rivers and the estuary in the Pearl River Delta, with the aim of investigating their spatial and vertical distributions. The concentrations of PFRs ranged from 8.3 to 470 ng/g dry weight with high levels of PFRs in the urban area and the e-waste recycling region. Generally, TPhP, TCPP, TEHP, TCEP, and TBEP were the dominant compounds of the PFRs, the composition of which varied across the different regions, reflecting the different sources of PFRs. In the estuary, the PFRs mainly derived from the Xijiang River and the Shunde sections. Increased concentrations of halogen-containing PFRs have been observed in the upper layers of the sediment core. Conversely, relatively high concentrations of halogen-free PFRs were observed in the lower layers of the sediment core, indicating different usage patterns or environmental behaviors between the halogen and the non-halogen PFRs in the study area.

  7. A magnetic record of heavy metal pollution in the Yangtze River subaqueous delta.

    Science.gov (United States)

    Dong, Chenyin; Zhang, Weiguo; Ma, Honglei; Feng, Huan; Lu, Honghua; Dong, Yan; Yu, Lizhong

    2014-04-01

    The rapid industrial development in the Yangtze River watershed over the last several decades has drawn great attention with respect to heavy metal pollution to the Yangtze River estuary and nearby coastal areas. In this study, a 236 cm long sediment core was retrieved from the Yangtze River subaqueous delta (122°36' E, 31°00' N) in 2008 and analyzed for magnetic properties and geochemical compositions to investigate heavy metal pollution history. The activity of (137)Cs peaked at depth 140 cm, with a broad plateau between 120 cm and 140 cm, suggesting an average sedimentation rate of 3.11 cm yr(-1) for the upper 140 cm layer. Magnetic susceptibility (χ), saturation isothermal remanent magnetization (SIRM), anhysteretic remanent magnetization (χARM) and heavy metal enrichment factors (EF) all showed an upward increase trend above depth 140 cm, suggesting that increased ferrimagnetic mineral concentration was accompanied by heavy metal enrichment in the sediment. Geochemical and granolumetric analyses showed that sediment sources and particle sizes played minor roles in the variations of magnetic properties. The effect of diagenesis, which can lead to the selective removal of magnetic minerals, was noticeable in the lower part of the core (140-236 cm). Co-variation between magnetic properties (χ, SIRM and χARM) and EF of Cu and Pb suggests that the elevated ferrimagnetic mineral concentration can be used as an indicator of heavy metal pollution in the reconstruction of environmental changes in estuarine and coastal settings.

  8. Estuarine science and decision-support tools to restore Puget Sound delta and estuarine ecosystems: The Skagit River Delta

    Science.gov (United States)

    Grossman, E. E.; Rosenbauer, R. J.; Takesue, R. K.; Gelfenbaum, G.; Reisenbichler, R.; Paulson, A.; Sexton, N. R.; Labiosa, B.; Beamer, E. M.; Hood, G.; Wyllie-Echeverria, S.

    2006-12-01

    Historic land use, ongoing resource extraction, and population expansion throughout Puget Sound have scientists and managers rapidly seeking effective restoration strategies to recover salmon (a cultural icon, as well as, a host of other endangered species and threatened habitats. Of principal concern is the reduction of salmon (Oncorhynchus spp.) and diminished carrying capacity of critical habitat in deltaic regions. Delta habitats, essential to salmon survival, have lost 70 to 80 % area since ~1850 and are now adjusting to a new suite of environmental changes associated with land use practices, including wetland restoration, and regional climate change. The USGS Coastal Habitats in Puget Sound Project, in collaboration with partners from the Skagit River System Cooperative, University of Washington, and other federal, state, and local agencies, is integrating geologic, biologic, hydrologic, and socioeconomic information to quantify changes in the distribution and function of deltaic-estuarine nearshore habitats and better predict "possible futures". We are combining detailed geologic and geochemical analyses of sedimentary environments, plant biomarkers (n-alkanes, PAHs, fatty-acids, and sterols), and compound-specific isotopes to estimate historic habitat coverage, eelgrass (Zostera marina) abundance and modern characteristics of nutrient cycling. Hydrologic and sediment transport processes are being measured to characterize physical processes shaping modern habitats including sediment transport and freshwater mixing that control the temporal and spatial pattern of substrate and water column conditions available as habitat. We are using geophysical, remote sensing, and modeling techniques to determine large-scale coastal morphologic and land-use change and characterize how alteration of physical, hydrologic, and biogeochemical processes influence the dynamics of freshwater mixing, and sediment and nutrient transport in the nearshore. To assist restoration

  9. Quantifying the patterns and dynamics of river deltas under conditions of steady forcing and relative sea level rise

    Science.gov (United States)

    Liang, Man; Van Dyk, Corey; Passalacqua, Paola

    2016-02-01

    Understanding deltaic channel dynamics is essential to acquiring knowledge on how deltas respond to environmental changes, as channels control the distribution of water, sediment, and nutrients. Channel-resolving morphodynamic models provide the basis for quantitative study of channel-scale dynamics, but they need to be properly assessed with a set of robust metrics able to quantitatively characterize delta patterns and dynamics before being used as predictive tools. In this work we use metrics developed in the context of delta formation, to assess the morphodynamic results of DeltaRCM, a parcel-based cellular model for delta formation and evolution. By comparing model results to theoretical predictions and field and experimental observations, we show that DeltaRCM captures the geometric growth characteristics of deltas such as fractality of channel network, spatial distribution of wet and dry surfaces, and temporal dynamics of channel-scale processes such as the decay of channel planform correlation. After evaluating the ability of DeltaRCM to produce delta patterns and dynamics at the scale of channel processes, we use the model to predict the deltaic response to relative sea level rise (RSLR). We show that uniform subsidence and absolute sea level rise have similar effects on delta evolution and cause intensified channel branching. Channel network fractality and channel mobility increase with higher-RSLR rates, while the spatial and temporal scales of avulsion events decrease, resulting in smaller sand bodies in the stratigraphy. Our modeling results provide the first set of quantitative predictions of the effects of RSLR on river deltas with a specific focus on the distributary channel network.

  10. Recent human impacts on the morphological evolution of the Yangtze River delta foreland: A review and new perspectives

    Science.gov (United States)

    Du, Jing-Long; Yang, Shi-Lun; Feng, Huan

    2016-11-01

    This paper reviews the morphological change in the Yangtze River delta due to increasing human impacts from three major aspects. The first is the reduction of sediment supply to the ocean due to dam construction, soil conservation, and sand mining within the Yangtze River basin. The reduced sediment supply has decreased the progradation rate of the delta and triggered erosion in the front of the delta. The second impact relates to the reclamation of intertidal wetlands by human activities. Since the 1950s, approximately 1100 km2 of intertidal land has been embanked, resulting in the disappearance of salt marshes and even the entire intertidal zone along some sections of the coastline. The third change in the delta due to human interference is the construction of deep-waterway structures at the mouth bar, which has greatly modified the local hydrodynamics and morphology. Sediment accretion has increased significantly in these areas as a result of sheltering by these deep-waterway structures. This review shows that human activities have severely altered the natural balance among the hydrodynamics and sediment supply, affecting the morphological features of the Yangtze River watershed and delta. Human impacts on the morphological evolution of deltaic coasts in general are becoming an increasingly concern, and more attention should be paid to the management and mitigation of these effects.

  11. Shallow Groundwater Movement in the Skagit River Delta Area, Skagit County, Washington

    Science.gov (United States)

    Savoca, Mark E.; Johnson, Kenneth H.; Fasser, Elisabeth T.

    2009-01-01

    Shallow groundwater movement in an area between the lower Skagit River and Puget Sound was characterized by the U.S. Geological Survey to assist Skagit County and the Washington State Department of Ecology with the identification of areas where water withdrawals from existing and new wells could adversely affect streamflow in the Skagit River. The shallow groundwater system consists of alluvial, lahar runout, and recessional outwash deposits composed of sand, gravel, and cobbles, with minor lenses of silt and clay. Upland areas are underlain by glacial till and outwash deposits that show evidence of terrestrial and shallow marine depositional environments. Bedrock exposures are limited to a few upland outcrops in the southwestern part of the study area, and consist of metamorphic, sedimentary, and igneous rocks. Water levels were measured in 47 wells on a quarterly basis (August 2007, November 2007, February 2008, and May 2008). Measurements from 34 wells completed in the shallow groundwater system were used to construct groundwater-level and flow-direction maps and perform a linear-regression analysis to estimate the overall, time averaged shallow groundwater-flow direction and gradient. Groundwater flow in the shallow groundwater system generally moves in a southwestward direction away from the Skagit River and toward the Swinomish Channel and Skagit Bay. Local groundwater flow towards the river was inferred during February 2008 in areas west and southwest of Mount Vernon. Water-level altitudes varied seasonally, however, and generally ranged from less than 3 feet (August 2007) in the west to about 15 feet (May 2008) in the east. The time-averaged, shallow groundwater-flow direction derived from regression analysis, 8.5 deg south of west, was similar to flow directions depicted on the quarterly water-level maps. Seasonal changes in groundwater levels in most wells in the Skagit River Delta follow a typical pattern for shallow wells in western Washington. Water

  12. PermVeg: A model to design crop sequences for permanent vegetable production systems in the Red River Delta, Vietnam

    NARCIS (Netherlands)

    Pham Thi Thu Huong, Huong; Everaarts, A.P.; Berg, van den W.; Neeteson, J.J.; Struik, P.C.

    2014-01-01

    The constraints in current vegetable production systems in the Red River Delta, Vietnam, in which vegetables are rotated with flooded rice, called for the design of alternative systems of permanent vegetable production. The practical model, PermVeg, was developed to generate vegetable crop sequences

  13. Role of photoexcited nitrogen dioxide chemistry on ozone formation and emission control strategy over the Pearl River Delta, China

    Science.gov (United States)

    A new hydroxyl radical formation pathway via photo-excited nitrogen dioxide chemistry is incorporated into a chemistry-only box model as well as a 3D air quality model to examine its potential role on ozone formation and emission control strategy over the Pearl River Delta region...

  14. Employee Training Needs and Perceived Value of Training in the Pearl River Delta of China: A Human Capital Development Approach

    Science.gov (United States)

    Au, Alan Kai Ming; Altman, Yochanan; Roussel, Josse

    2008-01-01

    Purpose: This paper aims to explore Hong Kong firms' training needs in the Pearl River Delta, a booming region in the fast growing People Republic of China economy, by resorting to a human capital approach. Also, to identify the training policies selected by those firms in order to cater for those needs. Design/methodology/approach: A survey based…

  15. Examining the Impact of Nitrous Acid Chemistry on Ozone and PM over the Pearl River Delta Region

    Science.gov (United States)

    The impact of nitrous acid (HONO) chemistry on regional ozone and particulate matter in Pearl River Delta region was investigated using the community multiscale air quality (CMAQ) modeling system and the CB05 mechanism. Model simulations were conducted for a ten-day period in Oct...

  16. Construction area expansion in relation to economic-demographic development and land resource in the Pearl River Delta of China

    NARCIS (Netherlands)

    Liu, Zhijia; Huang, Heqing; Werners, Saskia E.; Yan, Dan

    2016-01-01

    Since 1979, the Pearl River Delta (PRD) of China has experienced rapid socioeconomic development along with a fast expansion of construction area. Affected by both natural and human factors, a complex interdependency is found among the regional changes in construction area, GDP and population. A

  17. A geo-electric and gravimetric survey in the delta of the rivers Fluvia and Muga (Gerona), Spain

    NARCIS (Netherlands)

    Geirnaert, W.

    1976-01-01

    In the delta of the rivers Fluvia and Muga, the Quaternary is hydrogeologically the most important deposit. It is underlain by Pliocene marls and clays. From geo-electrical soundings and bore-hole data a map with depth contours of the Quaternary-Pliocene boundary plane was constructed. Near the coas

  18. A geo-electric and gravimetric survey in the delta of the rivers Fluvia and Muga (Gerona), Spain

    NARCIS (Netherlands)

    Geirnaert, W.

    1976-01-01

    In the delta of the rivers Fluvia and Muga, the Quaternary is hydrogeologically the most important deposit. It is underlain by Pliocene marls and clays. From geo-electrical soundings and bore-hole data a map with depth contours of the Quaternary-Pliocene boundary plane was constructed. Near the

  19. Carbon Sequestration in Mediterranean Tidal Wetlands: San Francisco Bay and the Ebro River Delta (Invited)

    Science.gov (United States)

    Callaway, J.; Fennessy, S.; Ibanez, C.

    2013-12-01

    Tidal wetlands accumulate soil carbon at relatively rapid rates, in large part because they build soil to counteract increases in sea-level rise. Because of the rapid rates of carbon sequestration, there is growing interest in evaluating carbon dynamics in tidal wetlands around the world; however, few measurements have been completed for mediterranean-type tidal wetlands, which tend to have relatively high levels of soil salinity, likely affecting both plant productivity and decomposition rates. We measured sediment accretion and carbon sequestration rates at tidal wetlands in two mediterranean regions: the San Francisco Bay Estuary (California, USA) and the Ebro River Delta (Catalonia, Spain). Sampling sites within each region represented a range of conditions in terms of soil salinity and plant communities, and these sites serve as potential analogs for long-term carbon sequestration in restored wetlands, which could receive credits under emerging policies for carbon management. Within San Francisco Bay, we collected six sediment cores per site at four salt marshes and two brackish tidal wetlands (two transects with three stations per transect at each site) in order to identify spatial variation both within and among wetlands in the Estuary. At the Ebro Delta, individual sediment cores were collected across 14 tidal wetland sites, including salt and brackish marshes from impounded areas, river mouths, coastal lagoon, and open bay settings. Cores were collected to 50 cm, and cores were dated using 137Cs and 210Pb. Most sites within San Francisco accreted 0.3-0.5 cm/yr, with slightly higher rates of accretion at low marsh stations; accretions rates based on 137Cs were slightly higher than those based on 210Pb, likely because of the shorter time frame covered by 137Cs dating. Accretion rates from the Ebro Delta sites were similar although more variable, with rates based on 137Cs ranging from 0.1 to 0.9 cm/yr and reflecting the wide range of conditions and management

  20. Vertical Migrating and Cluster Analysis of Soil Mesofauna at Dongying Halophytes Garden in Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    He Fu-xia; Xie Tong-yin; Xie Gui-lin; Fu Rong-shu

    2014-01-01

    For the first time, we used Tullgren method made a study on vertical migrating and cluster analysis of the soil mesofauna in Dongying Halophytes Garden in the Yellow River Delta (YRD), Shandong Province. The results showed that the soil mesofauna tended to gather on soil surface in most samples at most times, but the vertical migrating greatly varied in different seasons or environment conditions. Acari was the dominant group. The index of diversity of the soil fauna was correlated with the index of evenness. The Acari's number of individuals infected other species and numbers. Dominant group-Acari made greater contribution to the result of cluster analysis, and there were significant differences between communities in different habitats by cluster analysis with both Bray-Curtis and Jaccard similarity coefficient.

  1. Urbanization effect on precipitation over the Pearl River Delta based on CMORPH data

    Directory of Open Access Journals (Sweden)

    Sheng Chen

    2015-03-01

    Full Text Available Based on the satellite data from the Climate Prediction Center morphing (CMORPH at very high spatial and temporal resolution, the effects of urbanization on precipitation were assessed over the Pearl River Delta (PRD metropolitan regions of China. CMORPH data well estimates the precipitation features over the PRD. Compared to the surrounding rural areas, the PRD urban areas experience fewer and shorter precipitation events with a lower precipitation frequency (ratio of rainy hours, about 3 days per year less; however, short-duration heavy rain events play a more significant role over the PRD urban areas. Afternoon precipitation is much more pronounced over the PRD urban areas than the surrounding rural areas, which is probably because of the increase in short-duration heavy rain over urban areas.

  2. Urbanization signatures in strong versus weak precipitation over the Pearl River Delta metropolitan regions of China

    Energy Technology Data Exchange (ETDEWEB)

    Li Weibiao; Chen Sheng; Wen Zhiping; Wang Baomin [Department of Atmospheric Sciences, Sun Yat-sen University, Guangzhou 510275 (China); Chen Guixing; Sha Weimin [Department of Geophysics, Graduate School of Science, Tohoku University, Sendai (Japan); Luo Cong; Feng Yerong, E-mail: eeslwb@mail.sysu.edu.cn [Guangzhou Central Meteorological observatory, Guangzhou 510080 (China)

    2011-07-15

    We assess the issues of urban effects on the precipitation over the Pearl River Delta (PRD) metropolitan regions of China. The spatial and temporal variations of strong versus weak precipitation over the PRD and surrounding nonurban areas are investigated. The results show that the urbanization signatures in strong precipitation are significantly different from those in weak precipitation over the urban areas. The PRD experiences more strong precipitation but less weak precipitation compared to surrounding nonurban regions. In addition, the strong precipitation over the PRD displays a pronounced seasonal variation. The seasonality of weak precipitation, however, is much weaker over the PRD compared to the surrounding nonurban regions. Moreover, a strengthening in the precipitation intensity, a reduction in the rainfall frequency and an increase in the convective precipitation as well as the afternoon precipitation are found over the urban areas, which are probably associated with the abundance in strong precipitation and the deficit in weak precipitation over the PRD.

  3. Fouling in offshore areas southeast of the Zhujiang (Pearl) River Delta, the northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    Yan Tao; Yan Wenxia; Dong Yu; Liang Guanhe; Yan Yan; Wang Huajie

    2003-01-01

    In order to understand the type and extent of marine fouling in offshore areas southeast of the Zhujiang (Pearl) River delta, within the period form May 1986 to June 1987, two biological buoys were deployed at water depths of 95 m and 113 m located in 114 km and 160 km off the coast of Hong Kong, respectively. Moreover, the fouling community of a Marex hydrological buoy located in 115 m depth water 172 km off Hong Kong was also surveyed. The results show that a total of 78 species were collected and identified. The panels exposed for 3 months were mainly dominated by stalked barnacles Conchoderma hunteri and Lepas anatifera and hydroids Orthopyxis sp. As for the buoys, including the subsurface buoy, and their mooring systems exposed for 6 and 12 months, respectively, some hard foulers such as common oysters, pearl oysters, acorn barnacles and bryozoans were also found. The compositions of fouling communities also varied greatly with depth.

  4. Business Cost Increases Promote Industrial Restructuring in the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    江静; 刘志彪

    2007-01-01

    The traditional view holds that China’s comparative advantage lies in low costs,and it is therefore imperative to reduce business costs if China intends to maintain her industrial competitiveness.In the following article,Jiang Jing and Liu Zhibiao present a rather different point of view.They consider it endogenous to increase business costs.Although they may reduce urban competitiveness to a certain extent,increased business costs exert an important"push"effect upon structural adjustment and upgrade and the growth of the regional economy due to the varying degrees of sensitivity of manufacturing industries and producer service industries to business costs.These findings have been corroborated through their analysis of business costs and industrial distribution in Yangtze River Delta cities such as Shanghai,Nanjing, Suzhou,Wuxi and Nantong.

  5. Vegetation, substrate and hydrology in floating marshes in the Mississippi river delta plain wetlands, USA

    Science.gov (United States)

    Sasser, C.E.; Gosselink, J.G.; Swenson, E.M.; Swarzenski, C.M.; Leibowitz, N.C.

    1996-01-01

    In the 1940s extensive floating marshes (locally called 'flotant') were reported and mapped in coastal wetlands of the Mississippi River Delta Plain. These floating marshes included large areas of Panicum hemitomon-dominated freshwater marshes, and Spartina patens/Scirpus olneyi brackish marshes. Today these marshes appear to be quite different in extent and type. We describe five floating habitats and one non-floating, quaking habitat based on differences in buoyancy dynamics (timing and degree of floating), substrate characteristics, and dominant vegetation. All floating marshes have low bulk density, organic substrates. Nearly all are fresh marshes. Panicum hemitomon floating marshes presently occur within the general regions that were reported in the 1940's by O'Neil, but are reduced in extent. Some of the former Panicum hemitomon marshes have been replaced by seasonally or variably floating marshes dominated, or co-dominated by Sagittaria lancifolia or Eleocharis baldwinii. ?? 1996 Kluwer Academic Publishers.

  6. Identifying hotspots and management of critical ecosystem services in rapidly urbanizing Yangtze River Delta Region, China.

    Science.gov (United States)

    Cai, Wenbo; Gibbs, David; Zhang, Lang; Ferrier, Graham; Cai, Yongli

    2017-04-15

    Rapid urbanization has altered many ecosystems, causing a decline in many ecosystem services, generating serious ecological crisis. To cope with these challenges, we presented a comprehensive framework comprising five core steps for identifying and managing hotspots of critical ecosystem services in a rapid urbanizing region. This framework was applied in the case study of the Yangtze River Delta (YRD) Region. The study showed that there was large spatial heterogeneity in the hotspots of ecosystem services in the region, hotspots of supporting services and regulating services aggregately distributing in the southwest mountainous areas while hotspots of provisioning services mainly in the northeast plain, and hotspots of cultural services widespread in the waterbodies and southwest mountainous areas. The regionalization of the critical ecosystem services was made through the hotspot analysis. This study provided valuable information for environmental planning and management in a rapid urbanizing region and helped improve China's ecological redlines policy at regional scale. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Analysis of the Geomorphology and Environmental Geological Problems of Huzhou on the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    JIANG Yuehua; WANG Jingdong; YUAN Xueyin; WANG Runhua

    2004-01-01

    Geomorphically, Huzhou, which is on the Yangtze River delta is characterized mainly by plains, with small hills. This paper presents a detailed analysis of the environmental geological hazards both natural and those incurred by human activities in different morphologic units. The authors point out that most of the regional environmental geological problems in the natural geologic-morphologic conditions, such as crustal stability, foundation of soft soil, soil waterlogging and soil erosion, have insignificant effects to the society, or related countermeasures of prevention and control have been adopted. But environmental geological problems incurred by human being's economic activities become more and more severe, for example, water and soil pollution and land subsidence in plain areas resulting from overexploitation of groundwater, and landslides, karst collapses and water and soil loss etc. caused by quarrying in hilly areas.

  8. Quantifiable effectiveness of experimental scaling of river- and delta morphodynamics and stratigraphy

    Science.gov (United States)

    Kleinhans, Maarten G.; van Dijk, Wout M.; van de Lageweg, Wietse I.; Hoyal, David C. J. D.; Markies, Henk; van Maarseveen, Marcel; Roosendaal, Chris; van Weesep, Wendell; van Breemen, Dimitri; Hoendervoogt, Remko; Cheshier, Nathan

    2014-06-01

    Laboratory experiments to simulate landscapes and stratigraphy often suffer from scale effects, because reducing length- and time scales leads to different behaviour of water and sediment. Classically, scaling proceeded from dimensional analysis of the equations of motion and sediment transport, and minor concessions, such as vertical length scale distortion, led to acceptable results. In the past decade many experiments were done that seriously violated these scaling rules, but nevertheless produced significant and insightful results that resemble the real world in quantifiable ways. Here we focus on self-formed fluvial channels and channel patterns in experiments. The objectives of this paper are 1) to identify what aspects of scaling considerations are most important for experiments that simulate morphodynamics and stratigraphy of rivers and deltas, 2) to establish a design strategy for experiments based on a combination of relaxed classical scale rules, theory of bars and meanders, and small-scale experiments focussed at specific processes. We present a number of small laboratory setups and protocols that we use to rapidly quantify erosional and depositional types of forms and dynamics that develop in the landscape experiments as a function of detailed properties, such as effective material strength, and to assess potential scale effects. Most importantly, the width-to-depth ratio of channels determines the bar pattern and meandering tendency. The strength of floodplain material determines these channel dimensions, and theory predicts that laboratory rivers should have 1.5 times larger width-to-depth ratios for the same bar pattern. We show how floodplain formation can be controlled by adding silt-sized silicaflour, bentonite, Medicago sativa (alfalfa) or Partially Hydrolyzed PolyAcrylamide (a synthetic polymer) to poorly sorted sediment. The experiments demonstrate that there is a narrow range of conditions between no mobility of bed or banks, and too much

  9. Concentration of contaminants in breeding bird eggs from the Colorado River Delta, Mexico.

    Science.gov (United States)

    García-Hernández, Jaqueline; Sapozhnikova, Yelena V; Schlenk, Daniel; Mason, Andrew Z; Hinojosa-Huerta, Osvel; Rivera-Díaz, Juan José; Ramos-Delgado, Norma Alicia; Sánchez-Bon, Gerardo

    2006-06-01

    Organic contaminants (organochlorine [OC], organophosphorus [OP] pesticides and polychlorinated biphenyls [PCBs]), and metals (As, Cd, Hg, Pb, and Se) are a concern to avian health in the Colorado River delta, Mexico. We determined concentrations of contaminants in eggs of three breeding species of birds from the delta (mourning doves [Zenaida macroura], burrowing owls [Athene cunicularia], and marsh wrens [Cistothorus palustris]). We collected 27 eggs of mourning doves, eight eggs of burrowing owls, and 18 eggs of marsh wrens for analyses. Polychlorinated biphenyls, OC, and OP pesticides were analyzed by gas chromatography equipped with an electron capture detector, and metals were analyzed by inductively coupled plasma mass spectrometry. The non-ortho PCB congeners (PCB 77 and 126) were found in mourning dove and burrowing owl eggs at concentrations in which hatchability can be affected. Mean selenium concentration found in marsh wren eggs (5.6 microg/g dry wt) exceeded the level of concern. Arsenic and Cd were found at higher than normal concentrations, Hg concentrations did not exceed the level of concern in any of the species, and Pb concentrations were higher in eggs of species subject to hunting. With the exception of lead, marsh wren eggs contained the highest metal concentrations.

  10. Trace Gas Emissions from Extensive Aquaculture Systems in the Red River Delta, Vietnam

    Science.gov (United States)

    Beman, J.; Seto, K. C.

    2002-12-01

    The Red River Delta of Vietnam is an area undergoing rapid land use change. Aquaculture development is among the most significant of these transformations, with important economic, social and environmental effects. We explored the potential for managed mangrove' and `converted paddy' aquaculture systems in the Delta to produce and/or consume greenhouse gasses. We measured dissolved concentrations of the radiatively-important trace gasses methane (CH4) and nitrous oxide (N2O), as well as associated parameters. All ponds were super-saturated with CH4, with concentrations ranging from 132-1203 nM, (mean 561 nM) in managed mangrove, and 28-521 nM (mean 110 nM) in converted paddy. Surprisingly, none of the ponds was measurably supersaturated with N2O. Methane fluxes were calculated for all ponds using five well-accepted models of gas flux based on wind speed. Mean flux values ranged from 1.04 to 17.09 mg CH4 m-2 d-1 for managed mangrove, falling somewhere between fluxes reported for natural systems and those receiving sewage inputs. Further measurements should be made in more intensive systems to better understand the potential for trace gas production-particularly N2O-in aquaculture systems.

  11. Subsidence of River Delta Systems and Enclosed Basins Caused by Multi-decadal to Millennial Scale Sediment and Ocean Loading

    Science.gov (United States)

    Blom, Ronald G.; Ivins, Erik R.; Klemann, Volker; Dokka, Roy K.; Lohman, Rowena; Fielding, Eric J.

    2010-05-01

    The causes of multi-decadal coastal subsidence that exceed the rate of 20th-21st Century mean sea-level rise are numerous. A host of causal relationships between anthropogenic activity and coastal erosion and subsidence are both compelling and well understood. A short list of these processes should include: fluid extraction, reservoir compaction; fluid-induced motion of shallow growth-faults; decomposition of organic sediments (left in the wake of major water diversion projects) and sediment empoundment and/or diversion. Non-anthropogenic post-glacial sediment loading-induced subsidence has also been demonstrated to be a candidate mechanism that could dominate the GPS-mapped subsidence in the Mississippi-Atchafalaya Rive Delta system (Ivins, Dokka and Blum, GRL, 34, L16303, 2007). More recent changes in sediment load can also have a substantial impact on the active subsidence of the crust and mantle. These can be of both anthropogenic and natural origins. Here we examine, in varying degrees of detail, the world's major delta systems wherein the necessary and sufficient conditions are met that allow sediment plus water load to drive gravitationally-layered, hydrostatically pre-stressed viscoelastic Earth model simulations far enough away from gravitational equilibrium that a detectable geodetic signal in tide-gauges and GPS vertical position would be predicted. Sediment-load-induced subsidence occurs over horizontal length scales, λ, comparable to thickness of the lithosphere: λ ≥ 40-60 km and has amplitudes ranging from of 0.5 to 8 mm/yr (Ivins et al. GRL34, 2007; Syvitski Sustain. Sci., 3, 2008). The cases of the pan-Arctic deltas, the Atchafalya -Mississippi River Delta system, the Yangzte River and Yellow River Deltas of China, the Danube River Delta Plain, and the generally complex postglacial water-sediment loading of the Black Sea and Caspian Sea.

  12. Source apportionment of surface ozone in the Yangtze River Delta, China in the summer of 2013

    Science.gov (United States)

    Li, L.; An, J. Y.; Shi, Y. Y.; Zhou, M.; Yan, R. S.; Huang, C.; Wang, H. L.; Lou, S. R.; Wang, Q.; Lu, Q.; Wu, J.

    2016-11-01

    We applied ozone source apportionment technology (OSAT) with tagged tracers coupled within the Comprehensive Air Quality Model with Extensions (CAMx) to study the region and source category contribution to surface ozone in the Yangtze River Delta area in summer of 2013. Results indicate that the daytime ozone concentrations in the YRD region are influenced by emissions both locally, regionally and super-regionally. At urban Shanghai, Hangzhou and Suzhou receptors, the ozone formation is mainly VOC-limited, precursor emissions form Zhejiang province dominate their O3 concentrations. At the junction area among two provinces and Shanghai city, the ozone is usually influenced by all the three areas. The daily max O3 at the Dianshan Lake in July are contributed by Zhejiang (48.5%), Jiangsu (11.7%), Anhui (11.6%) and Shanghai (7.4%), long-range transport constitutes around 20.9%. At Chongming site, the BVOC emissions rate is higher than urban region. Regional contribution results show that Shanghai constitutes 15.6%, Jiangsu contributes 16.2% and Zhejiang accounts for 25.5% of the daily max O3. The analysis of the source category contribution to high ozone in the Yangtze River Delta region indicates that the most significant anthropogenic emission source sectors contributing to O3 pollution include industry, vehicle exhaust, although the effects vary with source sector and selected pollution episodes. Emissions of NOx and VOCs emitted from the fuel combustion of industrial boilers and kilns, together with VOCs emissions from industrial process contribute a lot to the high concentrations in urban Hangzhou, Suzhou and Shanghai. The contribution from regional elevated power plants cannot be neglected, especially to Dianshan Lake. Fugitive emissions of volatile pollution sources also have certain contribution to regional O3. These results indicate that the regional collaboration is of most importance to reduce ambient ozone pollution, particularly during high ozone episodes.

  13. Effects of drought on birds and riparian vegetation in the Colorado River Delta, Mexico

    Science.gov (United States)

    Hinojosa-Huerta, Osvel; Nagler, Pamela L.; Carrillo-Guererro, Yamilett K.; Glenn, Edward P.

    2013-01-01

    The riparian corridor in the delta of the Colorado River in Mexico supports internationally important bird habitat. The vegetation is maintained by surface flows from the U.S. and Mexico and by a high, non-saline aquifer into which the dominant phreatophytic shrubs and trees are rooted. We studied the effects of a regional drought on riparian vegetation and avian abundance and diversity from 2002 to 2007, during which time surface flows were markedly reduced compared to the period from 1995 to 2002. Reduced surface flows led to a reduction in native tree cover but an increase in shrub cover, mostly due to an increase in Tamarix spp., an introduced halophytic shrub, and a reduction in Populus fremontii and Salix gooddingii trees. However, overall vegetation cover was unchanged at about 70%. Overall bird density and diversity were also unchanged, but riparian-obligate species tended to decrease in abundance, and generalist species increased. Although reduction in surface flows reduced habitat value and negatively impacted riparian-obligate bird species, portions of the riparian zone exhibited resilience. Surface flows are required to reduce soil salt levels and germinate new cohorts of native trees, but the main source of water supporting this ecosystem is the aquifer, derived from underflows from irrigated fields in the U.S. and Mexico. The long-term prospects for delta riparian habitats are uncertain due to expected reduced flows of river water from climate change, and land use practices that will reduce underflows to the riparian aquifer and increase salinity levels. Active restoration programs would be needed if these habitats are to be preserved for the future.

  14. High resolution aerosol optical thickness retrieval over the Pearl River Delta region with improved aerosol modelling

    Institute of Scientific and Technical Information of China (English)

    WONG; ManSing; NICHOL; Janet; LEE; Kwon; Ho

    2009-01-01

    Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, a new aerosol retrieval algorithm using the MODIS 500 m resolution images is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta region. The rationale of our technique is to first estimate the aerosol reflectance by decomposing the top-of-atmosphere reflectance from surface reflectance and Rayleigh path reflectance. For the determination of surface reflectance, a modified Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. A strong correlation is shown between the surface reflectance of MRT images and MODIS land surface reflectance products (MOD09), with a value of 0.9. For conversion of aerosol reflectance to Aerosol Optical Thickness (AOT), comprehensive Look Up Tables (LUT) are constructed, in which aerosol properties and sun-viewing geometry in the radiative transfer calculations are taken into account. Four aerosol types, namely mixed urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on three years of AERONET measurements in Hong Kong. Their aerosol properties were input for LUT calculation. The resulting 500 m AOT images are highly correlated (r = 0.89) with AERONET sunphotometer observations in Hong Kong. This study demonstrates the applicability of aerosol retrieval at fine resolution scale in urban areas, which can assist the study of aerosol loading distribution and the impact of localized and transient pollution on urban air quality. In addition, the MODIS 500 m AOT images can be used to study cross

  15. High resolution aerosol optical thickness retrieval over the Pearl River Delta region with improved aerosol modelling

    Institute of Scientific and Technical Information of China (English)

    WONG ManSing; NICHOL Janet; LEE Kwon Ho; LI ZhanQing

    2009-01-01

    Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, a new aerosol retrieval algorithm using the MODIS 500 m resolu-tion images is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta re-gion. The rationale of our technique is to first estimate the aerosol reflectance by decomposing the top-of-atmosphere reflectance from surface reflectance and Rayleigh path reflectance. For the deter-mination of surface reflectance, a modified Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. A strong correlation is shown between the surface reflec-tance of MRT images and MODIS land surface reflectance products (MOD09), with a value of 0.9. For conversion of aerosol reflectance to Aerosol Optical Thickness (AOT), comprehensive Look Up Tables (LUT) are constructed, in which aerosol properties and sun-viewing geometry in the radiative transfer calculations are taken into account. Four aerosol types, namely mixed urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on three years of AERONET measurements in Hong Kong. Their aerosol properties were input for LUT calculation. The resulting 500 m AOT images are highly correlated (r=0.89) with AERONET sunphotometer observations in Hong Kong. This study demonstrates the applicability of aerosol retrieval at fine resolution scale in urban areas, which can assist the study of aerosol loading distribution and the impact of localized and transient pollution on urban air quality. In addition, the MODIS 500 m AOT images can be used to study cross

  16. Historical Reconstruction of Organic Carbon Inputs to Sediments in the Colville River Delta, Alaska: The Application of Biomarker Proxies

    Science.gov (United States)

    Zhang, X.; Bianchi, T. S.; Allison, M. A.

    2014-12-01

    Arctic permafrost represents about 50% of the total belowground global carbon pool, and thus the fate of this pool, as it thaws in the wake of global warming, warrants close attention. Large-river delta-front estuaries (LDEs) have been shown to be important recorders of natural and human-induced changes in watersheds, as they are critical zones for the exchange of organic carbon between the continents and the ocean. The Colville River is the largest North American Arctic River with a continuous permafrost watershed. Simpson's Lagoon, an eastward distal component of the Colville River Delta is an excellent location for historical reconstruction work since it is an area well protected from intense ice grounding and has minimal bioturbation. Sediment cores were collected from the mouth of the river and the lagoon in August of 2010, and analyzed for bulk organic carbon and nitrogen proxies, biomarkers (including lignin phenols, fatty acids), and compound-specific 13C isotope analysis (CSIA) of fatty acids. Downcore sediment data from CSIA of short-chain fatty acids (C14-C18) to the delta over the past ca. 50 years were found to be more depleted and had a wider isotopic range (-17.0~-33.2‰) than long-chain fatty acids (C22-C30, -30.3~-36.8‰). This possibly reflects alterations of inputs of freshwater flow to the delta which could have resulted in isotopic changes that caused corresponding changes in marine versus freshwater phytoplankton inputs. Downcore short-chain saturated and monounsaturated fatty acid profiles reflected differences in the abundance of bacteria and post-depositional decay of algal inputs across different regions of the delta. Ongoing analyses will also focus on compound-specific radiocarbon analyses (CSRA) of fatty acids and lignin phenols to better understand the changes of organic inputs from terrestrially-derived organic-rich horizons in surface soils vs. old deep permafrost-derived organic horizons.

  17. Recent morphological changes of the Yellow River (Huanghe) submerged delta: Causes and environmental implications

    Science.gov (United States)

    Jiang, Chao; Pan, Shunqi; Chen, Shenliang

    2017-09-01

    The Yellow River (Huanghe) submerged delta (YRSD) has been under the threat of erosion and retreat during the Anthropocene due to dramatic climatic and anthropogenic changes in the Yellow River basin. The analysis of field data shows that over the period of 1977-2005, the changes in climate (decrease in precipitation and increase in air temperature) and human interventions (increase in water diversion projects) throughout the watershed have resulted in the sharp reductions of river flow and sediment discharges into the Bohai Sea. Consequently, over the decadal timescale, morphological evolution of the YRSD has gone through three stages: i.e. rapid accumulation (5.77 × 108 m3/year) in 1977-1985, moderate accumulation (3.80 × 108 m3/year) in 1986-1995 and slow accumulation (0.91 × 108 m3/year) in 1996-2005. Climatic change within the catchment characterized by the rapid increase of air temperature contributed significantly to the transitions from the rapid accumulation to the moderate accumulation, and to the subsequent slow accumulation. The decadal morphological changes of the YRSD also show peculiar deposition/erosion characteristics over the medium timescale under river input reduction. Within the three decades, the patterns of the main sedimentary body exhibit irregular ellipses with the long axis parallel to the - 5 or - 10 m isobaths and short axis perpendicular to the isobaths. The depocentres of the YRSD are located between the - 10 and - 15 m isobaths close to the respective river mouths, with a high vertical accretion rate of 1.20 m/year. The time series data of annual volumetric change of the YRSD and river sediment load from 1977 to 2005 further demonstrate significant linear positive relationships between deltaic geomorphic change and fluvial input over shorter timescales (annual and 3-year). The critical sediment discharges for maintaining the deposition/erosion equilibrium state of the YRSD over the annual and 3-year timescales are found to be 1

  18. Health impact assessment of marine emissions in Pearl River Delta region.

    Science.gov (United States)

    Lai, H K; Tsang, H; Chau, J; Lee, C H; McGhee, S M; Hedley, A J; Wong, C M

    2013-01-15

    Global marine vessels emissions are adversely affecting human health particularly in southeast Asia. But health burdens from both ocean- and river-going vessels in Pearl River Delta (PRD) regions are not quantified. We estimated the potential health impacts using pooled relative risks of mortality and hospital admissions in China, and the model derived concentrations of sulfur dioxide (SO₂), particulate matter (PM₁₀), nitrogen dioxide (NO₂) and ozone (O₃) due to vessels emissions. SO₂ concentrations due to marine emissions in Hong Kong were 13.6 μg m⁻³ compared with 0.7 μg m⁻³ in PRD regions that were far from the marine vessels. In PRD regions, the estimated annual numbers (per million people) of excess deaths from all natural causes and hospital admissions from cardiorespiratory causes attributable to SO₂, NO₂, O₃ and PM₁₀ combined from marine emissions were 45 and 265 respectively. Marine emission control measures could contribute a large reduction in mortality and hospital admissions in PRD regions especially in Hong Kong.

  19. Interactions between the flooding regime and floodplain grasslands in the Tana River Delta, in Kenya

    Science.gov (United States)

    Leauthaud, Crystele; Musila, Winfred; Duvail, Stéphanie; Kergoat, Laurent; Hiernaux, Pierre; Grippa, Manuela; Albergel, Jean

    2017-04-01

    The floodplain grasslands of the Tana River Delta, located on the East African coast in Kenya, form part of an intertwined socio-ecological deltaic system of high biodiversity value that delivers numerous goods and services. Mainly composed of Echinochloa stagnina (Retz) P. Beauv., a high-value forage species, this ecosystem is the major dry-season grazing grounds of the local pastoralist communities. The construction of hydroelectric infrastructure has led to a modification of the flooding regime. The impacts of the resulting reduction of floods in the deltaic zone on ecosystem properties and services still need to be assessed. In such a perspective, this study characterizes the link between the flooding regime of the Tana River and the growth pattern of its floodplain grassland. Aboveground dry phytomass was sampled for 15 months under a wide variety of naturally flooded and non-flooded conditions and controlled irrigation and cutting frequency treatments. Annual aboveground dry phytomass attained high values between 11 T.ha-1 and 32 T.ha-1 and annual net primary production of the grasslands reached 35 T.ha-1.year-1. Growth rates clearly depended on the flooding regime, management and climate conditions and were on average more than twice as fast during, and 50% faster after the floods, relative to pre-flood conditions. A plant growth model allowed testing the effect of different flooding regimes on plant productivity, confirming very low productivity in the absence of floods. These results suggest that rangeland and water management for the Tana River deltaic wetlands are tightly linked. The projected construction of another dam could lead to a reduction of flood extent and period and a decrease of grassland productivity and growth duration. Mitigation of this type of negative impacts, which will have direct and adverse consequences for the pastoralist communities as well as on the delivery of other goods and services, needs to be undertaken.

  20. Behaviors of extreme water level in the Pearl River Delta and possible impacts from human activities

    Directory of Open Access Journals (Sweden)

    Y. D. Chen

    2007-12-01

    Full Text Available Trends and variations of the extreme water levels defined as exceeding/falling below certain thresholds (mean ± std across the Pearl River Delta (PRD are systematically explored using the linear regression method. Research results indicate that: 1 The upper PRD is dominated by the significant decreasing low water level, and significant increasing low water level can be identified in the lower PRD. The variations of the relative frequency of the high water level are characterized by the decreasing variability in the middle PRD. However more stations show significant changes of the relative frequency of the low water level across the PRD. No confirmative changing patterns of the relative frequency of the low water level can be detected in the middle PRD; 2 When it comes to the seasonal variations of the high/low water level in JJA (high flow periods in the PRD, stations located closer to the estuary tend to exhibit increasing high/low water level. However stations located closer to the upper PRD tend to show decreasing high/low water level. Similar patterns can be identified in the high/low water level in DJF (low flow periods in the PRD; 3 The changes of the water level in the PRD are heavily affected by human interferences, e.g. in-channel dredging, sand mining and the construction of levees. The stations dominated by decreasing water level are mostly located along the river channels featured by highly-intensive dredging. The stations along the coastal regions show significant increasing extreme high/low water level. The coastal regions are not influenced by in-channel dredging, and furthermore, sediment loads from upper and middle PRD are deposited in the river mouths and which will tend to raise the water level in the estuary of the PRD. The findings of this paper may be helpful for local water resource management.

  1. The influence of paleogeography in epicontinental seas: A case study based on Middle Devonian strata from the MacKenzie Basin, Northwest Territories, Canada

    Science.gov (United States)

    Corlett, Hilary; Jones, Brian

    2011-08-01

    The history of Middle Devonian sea level changes are recorded in the Chinchaga Formation, Lonely Bay Formation, Horn Plateau Formation, and the Horn River Formations that originated in the MacKenzie Basin, which is located in the southern Northwest Territories, Canada. These strata record an almost consistent sea-level rise throughout the Middle Devonian with punctuated deepenings. Deposition began in the MacKenzie Basin in the Eifelian with restricted shallow water evaporites and dolomites of the Chinchaga Formation. Overlying the Chinchaga Formation are the open-marine carbonates belonging to the Lonely Bay Formation, which were overlain by the Horn Plateau Formation buildups. Pelagic shales of the Horn River Formation in the Late Givetian/Early Frasnian later covered these buildups. During the Early and Middle Devonian many continental basins in North America had limited interactions with open ocean waters. These restricted shallow-water basins were vulnerable to the effects of clastic shedding and evaporitic drawdown that commonly caused local lowstands. Several of these shallow basins, including the MacKenzie Basin, have been used to construct Devonian sea-level curves. Comparison of the Middle Devonian strata that formed in the MacKenzie Basin with well-established sea level curves shows that the Late-Givetian regression interpreted from some of those successions is not evident in the succession found in the MacKenzie Basin. This probably reflects the fact that the Mackenzie Basin was directly linked to the open ocean and was not influenced by the changes in sea level that affected many of the enclosed basins.

  2. High-resolution (spatial and temporal) Hydrodynamic Modeling in the Lower Mississippi River Delta

    Science.gov (United States)

    Karadogan, E.; Danchuk, S.; Berger, C.; Brown, G.; Willson, C.

    2007-12-01

    The lower Mississippi River is a highly engineered system existing in one of the world's largest deltas. This system is subject to a variety of spatial and temporal forcings due to its large watershed (drains about 41% of the continental U.S.) and from the Gulf of Mexico. Future perturbations on this system are anticipated due to the impacts of global climate change (e.g., rising eustatic sea level, changes in weather patterns) and from proposed modifications to the system such as diversion structures aimed at providing freshwater nutrients and sediments to the rapidly degrading coastal wetlands. Numerical modeling will play a large role in improving our understanding and management of the system and the ability to properly design future structural features. These models will need to have the necessary spatial and temporal resolution to account for the many important processes in the river, the Gulf of Mexico, and in the wetland areas where small distributary channels will form and wetting/drying must be accounted for. This paper will investigate the ability of a 2D shallow water and sediment model to reproduce the complex distributary development associated with flow diversions into quiescent bays. A reach of the Lower Mississippi River from Point a la Hache to the Gulf of Mexico was used as a test domain to evaluate the performance and capabilities of the U.S. Army Corps of Engineers ADaptive Hydraulics (ADH) model. ADH is an unstructured finite element modeling system that includes unsaturated Richards' equations for groundwater, Navier Stokes for nonhydrostatic flow calculations, and Shallow Water equations. ADH conducts automated refinement and coarsening of the mesh based upon flow characteristics. In this case the 2D shallow water model is being used. It includes coupled flow and sedimentation. An unstructured mesh was developed for the study area which includes detailed bathymetry and topography from available survey data. The mesh is fine enough to capture

  3. Sandy River Delta Habitat Restoration : Annual Report, January 2008 - March 2009.

    Energy Technology Data Exchange (ETDEWEB)

    Dobson, Robin [USDA Forest Service, Columbia River Gorge National Scenic Area

    2009-09-11

    During the period 2008-2009, there were 2 contracts with BPA. One (38539) was dealing with the restoration work for 2007 and the other (26198) was an extension on the 2006 contract including the NEPA for Dam removal on the old channel of the Sandy River. For contract 38539, the Sandy River Delta Habitat Restoration project continued its focus on riparian hardwood reforestation with less emphasis on wetlands restoration. Emphasis was placed on Sundial Island again due to the potential removal of the dike and the loss of access in the near future. AshCreek Forest Management was able to leverage additional funding from grants to help finance the restoration effort; this required a mid year revision of work funded by BPA. The revised work not only continued the maintenance of restored hardwood forests, but was aimed to commence the restoration of the Columbia River Banks, an area all along the Columbia River. This would be the final restoration for Sundial Island. The grant funding would help achieve this. Thus by 2011, all major work will have been completed on Sundial Island and the need for access with vehicles would no longer be required. The restored forests continued to show excellent growth and development towards true riparian gallery forests. Final inter-planting was commenced, and will continue through 2010 before the area is considered fully restored. No new wetland work was completed. The wetlands were filled by pumping in early summer to augment the water levels but due to better rainfall, no new fuel was required to augment existing. Monitoring results continued to show very good growth of the trees and the restoration at large was performing beyond expectations. Weed problems continue to be the most difficult issue. The $100,000 from BPA planned for forest restoration in 2008, was augmented by $25,000 from USFS, $120,000 from OR150 grant, $18,000 from LCREP, and the COE continued to add $250,000 for their portion. Summary of the use of these funds are

  4. River Bookends: Headwaters, Delta and the Volumes of Stories in Between

    Science.gov (United States)

    Waller, J. L.; Brey, J. A.

    2016-12-01

    As professors of art and earth science, we were often pleased when our students found that integrating lessons of geoscience with art rewarded them in impactful and memorable ways. Inspired by student success and our very real concern for natural and human caused threats to treasured cities and areas on the globe, we produced "Layers: Places in Peril", a gallery exhibition of paintings and scientific explanation essays. We found the combination of art and earth science was a powerful tool that touched and informed a wide and diverse population beyond classrooms. Acutely aware that current crises facing Earth are not limited to gigantic forces, we then produced "small problems, BIG TROUBLE" that addressed how seemingly small problems lead to far-reaching threats. Our conversation expanded to include twenty other scientists from geoscience, biology, physics and chemistry whose science-based essays paired with Waller's paintings. In our newest presentation in production, River Bookends: Headwaters, Delta and the Volumes of Stories in Between, we address art and geo-cultural connections associated with World rivers. Our exploration is focused on rivers as markers of time, culture and identity, yet, the importance of stressing the geoscience in this exhibition is large, indeed. An understanding of geomorphology and river ecology and of the historical changes, both natural and human-engineered which may dramatically give rise to, enrich, distress, or ultimately destroy human settlements and culture, are essential to our intended emphases in the show. In this session, we will describe these exhibitions, show images of the work and discuss some of the gallery activities that resulted from the shows, which included a discussion panel of social science and humanities faculty focused on the exhibition topics. We will describe how local high school art and science students answered our invitation to create a parallel exhibition of our show premise, concurrently exhibited in an

  5. The Colorado river delta (Mexico: ecological importance and management = O delta do rio Colorado (Mexico: importância ecológica e gerenciamento

    Directory of Open Access Journals (Sweden)

    José Luis Fermán Almada

    2008-10-01

    Full Text Available The Colorado river delta is a unique coastal system in the world, as it combines two important systems: the Colorado river and the Gulf of California. Consequently, the delta is dominated by bilateral interests, and influenced by administrative, political and natural processes, which involve the countries of the United States and Mexico. Located in the northern part of the Gulf of California, under a condition of natural isolation, a series of environmental attributeshave been developed (biotic and abiotic that are only observed in is region. In this work, the development of the bilateral political relations and the most important ecological characteristicsare presented, as well as the management instruments that have been developed for over 80 years. From these issues, the possible scenario for the region is defined, and the development of methodologies for monitoring the effects of these possible tendencies on the natural components of the delta is proposed.O delta do rio Colorado é uma zona costeira única em todo o mundo, porassociar dois importantes sistemas: o próprio rio Colorado e o Golfo da Califórnia. Conseqüentemente, o delta é dominado por interesses bi-nacionais e influenciado por processos administrativos, políticos e naturais, envolvendo os Estados Unidos e o México. Localizado no norte do Golfo da Califórnia, sob uma condição de isolamento natural,desenvolveu-se uma série de atributos ambientais (bióticos e abióticos que só podem ser vistos nessa região. Neste trabalho, são apresentados o desenvolvimento das relações políticas bilaterais e as características ecológicas mais importantes, bem como osmecanismos de gerenciamento que vêm sido desenvolvidos por mais de 80 anos. A partir dessas questões, é definido um cenário tendencial possível para a região, e o desenvolvimento de metodologias para o acompanhamento dos efeitos dessas possíveis tendências sobre os componentes naturais do delta é proposto.

  6. Architecture analysis of a river flood-dominated delta during an overall sea-level rise (early Pliocene, SE Spain)

    Science.gov (United States)

    García-García, F.; Corbí, H.; Soria, J. M.; Viseras, C.

    2011-05-01

    The sedimentary record of delta-front to prodelta transition that developed during the early Pliocene (Bajo Segura Basin, peri-Mediterranean Betic Cordillera Basin) represents an unusual infilling of an incised valley cutting downwards into late Messinian pelagic marls. The complete delta succession, less than 65 m thick, consists of four upwardly fining and thinning sequences several metres thick. Each sequence consists of basal conglomeratic and coarse-grained sandstone beds (delta-front deposits) evolving upwards to alternating sandstones and silty-marl beds (prodelta deposits). The retrogradational stratal succession pattern is interpreted as having been deposited during an overall sea-level rise. Facies association is characterised by quasi- to planar-laminated sandstones and pebbly sandstones alternating with clast-supported boulders to pebbles, sheet-like climbing cross-laminated sandstones with abundant plant remains, and epsilon cross-stratified and channelized gravels and sandstones. These are interpreted as having been deposited by highly concentrated flows interpreted as hyperpycnal turbidity flows from high (cohesionless debris flows and sinuous submarine channels) to moderate (sheet-like climbing cross-laminated sandstones) discharge river-flood events. Slabs of sediment from unstable banks, outsized clasts which roll onto thin beds from channel mouths, slumps and intraformational breccias in delta front are other signatures (including a lack of bored clasts) which indicate high-energy and rapid deposition at the river mouth, encouraging the delta-front gravitational instability failures. Major changes in the discharge of the river-fed delta could have been caused by brief catastrophic, heavy-precipitation events coupled with quasi-stationary convective orographic rainfall typical of the modern Mediterranean.

  7. Sustainability of massively anthropic deltas via dispersal of sediment to manage land building: results from two unique case studies, the Mississippi River (U.S.A.) and the Yellow River (China) deltas

    Science.gov (United States)

    Nittrouer, Jeffrey

    2016-04-01

    studies of both the Mississippi and Yellow rivers have been used to inform and validate numerical modeling efforts that seek to replicate the morphodynamics of the two diversions. The aim is to evaluate best practices for building deltaic landscape. Based on these research efforts, there are key similarities found for the delta systems: 1) coarse (sandy) sediment is the primary contributor to subaerial delta development, despite the abundance of mud for both rivers; 2) the influx of freshwater into estuarine regions of deltas has tremendous impact on vegetation development, and therefore the cohesion of the deltaic sediment deposit; and 3) it is feasible to produce efficient diversions that maximize sediment delivery and still provide for continued use of the riverine resource (for example, navigation of the channel by vessels). These findings are critical when considering future plans that seek sustainable management practices of other large, anthropic fluvial deltaic systems.

  8. Hydrogeological modeling of water exchange between a river valley aquifer and the Colorado River at a riparian corridor of the Colorado River Delta

    Science.gov (United States)

    Perez-Gonzalez, D.; Ramirez-Hernandez, J.; Zamora, F.

    2008-05-01

    The Colorado River Delta has shown a high capacity of regeneration in spite of the drastic reduction of the freshwater flows. This river has an important ecological value for the remaining ecosystems at the regional and continental level. It is not known when this river will present again surpluses of superficial water in the basin, as it happened in the decades of 1980 and 1990. The ecosystems of the Delta depend on the availability of groundwater to survive. The practices of blanket irrigation in the Valley of Mexicali have favored the vertical refill of the aquifer. Part of this water that infiltrates the ground is captured by the Colorado River (CR). As a consequence, even in years in which the CR has not received surpluses of superficial water low flow can be observed in the river, especially in the area of our study that comprises 12 km of the CR between the interception of the railroad with the river and the entrance to Carranza City. This low flow provides water to maintain the riparian vegetation of the zone. For this reason, it is important to know the hydrologic relationship between the river aquifer and the CR. The purpose of this work is to determine the volumes of water supplied by the aquifer to the riparian system and its relationship with the vegetation. Measurements of the fluctuations of the freatic level (FL) in 27 boreholes located in 8 cross sections during more than 2 years have been used for this study. The system was modelled using the program MODFLOW considering diverse water levels in the CR and flow exchange with the aquifer. The hydrogeological properties of the aquifer were found from slug tests and correlations with the textures of 100 soil samples. The modeling results allow to separate the zone of study in three sections. The first one extends 5km from the railroad to the south. In this section the CR receives water from the aquifer producing the observed water in the river bed all the year. The second section, of approximately 2 km

  9. Application of Remote Sensing Detection and GIS in Analysis of Vegetation Pattern Dynamics in the Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    Song Chuangye; Liu Gaohuan

    2008-01-01

    Regional vegetation pattern dynamics has a great im-pact on ecosystem and climate change. Remote sensing data and geographical information system (GIS) analysis were widely used in the detection of vegetation pattern dynamics. In this study, the Yellow River Delta was selected as the study area. By using 1986, 1993, 1996, 1999 and 2005 remote sensing data as basic informa-tion resource, with the support of GIS, a wetland vegetation spa-tial information dataset was built up. Through selecting the land-scape metrics such as class area (CA), class percent of landscape (PL), number of patch (NP), largest patch index (LPI) and mean patch size (MPS) etc., the dynamics of vegetation pattern was analyzed. The result showed that the change of vegetation pattern is significant from 1986 to 2005. From 1986-1999, the area of the vegetation, the percent of vegetation, LPI and MPS decreased, the NP increased, the vegetation pattern tends to be fragmental. The decrease in vegetation area may well be explained by the fact of the nature environment evolution (Climate change and decrease in Yellow River runoff) and the increase in the population in the Yellow River Delta. However, from 1999-2005, the area of the vegetation, the percent of vegetation, LPI and MPS increased, while the NP decreased. This trend of restoration may be due to the implementation of water resources regulation for the Yellow River Delta since 1999.

  10. Trace metals distribution in synodontis membranaceus, sediments, Asystasia Gangetica and Platostoma Africanium from Ofuafor River around Delta Glass Factory in Ughelli North Local Government Area, Delta State Nigeria

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The trace metals analysis in synodontis membranaceus (Head and Tail), Bottom sediments, Asystasia Gangetica and Platostoma Africanium were carried out using atomic absorption spectrometer of model perkin Elmer 3110. Metals analysed were copper, nickel, mangenese, chromium, iron lead and cobalt. These metals were detected in the above samples. Vegetation samples concentration in copper, manganese, Chromium, iron and Cobalt were higher than those obtained in bottom sediments. The tail part of the fish contents of trace metals were also higher than those of the head. The results obtained in this work exceeded the results of water analysis carried out by Omoregha on the same river. Metals such as copper, nickel, manganese and chromium were below detection limit in the water from the same river. The bioaccumulation of these trace metals in these samples were traced to activities of Delta Glass factory.

  11. Distribution and pollution, toxicity and risk assessment of heavy metals in sediments from urban and rural rivers of the Pearl River delta in southern China.

    Science.gov (United States)

    Xiao, Rong; Bai, Junhong; Huang, Laibin; Zhang, Honggang; Cui, Baoshan; Liu, Xinhui

    2013-12-01

    Sediments were collected from the upper, middle and lower reaches of both urban and rural rivers in a typical urbanization zone of the Pearl River delta. Six heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) were analyzed in all sediment samples, and their spatial distribution, pollution levels, toxicity and ecological risk levels were evaluated to compare the characteristics of heavy metal pollution between the two rivers. Our results indicated that the total contents of the six metals in all samples exceeded the soil background value in Guangdong province. Based on the soil quality thresholds of the China SEPA, Cd levels at all sites exceeded class III criteria, and other metals exhibited pollution levels exceeding class II or III criteria at both river sites. According to the sediment quality guidelines of the US EPA, all samples were moderately to heavily polluted by Cr, Cu, Ni, Pb and Zn. Compared to rural river sites, urban river sites exhibited heavier pollution. Almost all sediment samples from both rivers exhibited moderate to serious toxicity to the environment, with higher contributions from Cr and Ni. A "hot area" of heavy metal pollution being observed in the upper and middle reaches of the urban river area, whereas a "hot spot" was identified at a specific site in the middle reach of the rural river. Contrary metal distribution patterns were also observed along typical sediment profiles from urban and rural rivers. However, the potential ecological risk indices of rural river sediments in this study were equal to those of urban river sediments, implying that the ecological health issues of the rivers in the undeveloped rural area should also be addressed. Sediment organic matter and grain size might be important factors influencing the distribution profiles of these heavy metals.

  12. Groundwater response to the 2014 pulse flow in the Colorado River Delta

    Science.gov (United States)

    Kennedy, Jeffrey; Rodriguez-Burgueno, Eliana; Ramirez-Hernandez, Jorge

    2017-01-01

    During the March-May 2014 Colorado River Delta pulse flow, approximately 102 × 106 m3 (82,000 acre-feet) of water was released into the channel at Morelos Dam, with additional releases further downstream. The majority of pulse flow water infiltrated and recharged the regional aquifer. Using groundwater-level and microgravity data we mapped the spatial and temporal distribution of changes in aquifer storage associated with pulse flow. Surface-water losses to infiltration were greatest around the Southerly International Boundary, where a lowered groundwater level owing to nearby pumping created increased storage potential as compared to other areas with shallower groundwater. Groundwater levels were elevated for several months after the pulse flow but had largely returned to pre-pulse levels by fall 2014. Elevated groundwater levels in the limitrophe (border) reach extended about 2 km to the east around the midway point between the Northerly and Southerly International Boundaries, and about 4 km to the east at the southern end. In the southern part of the delta, although total streamflow in the channel was less due to upstream infiltration, augmented deliveries through irrigation canals and possible irrigation return flows created sustained increases in groundwater levels during summer 2014. Results show that elevated groundwater levels and increases in groundwater storage were relatively short lived (confined to calendar year 2014), and that depressed water levels associated with groundwater pumping around San Luis, Arizona and San Luis Rio Colorado, Sonora cause large, unavoidable infiltration losses of in-channel water to groundwater in the vicinity.

  13. Relevance of the Paraná River hydrology on the fluvial water quality of the Delta Biosphere Reserve.

    Science.gov (United States)

    Puig, Alba; Olguín Salinas, Héctor F; Borús, Juan A

    2016-06-01

    The increasing frequency of extreme events in large rivers may affect not only their flow, but also their water quality. In the present study, spatial and temporal changes in fluvial physico-chemical variables were analyzed in a mega-river delta during two extreme hydrological years (La Niña-El Niño) and related to potential explanatory factors. Basic water variables were evaluated in situ at 13 points (distant 2-35 km from each other) in watercourses of the Delta Biosphere Reserve (890 km(2)) in the Lower Paraná River (Argentina) in nine surveys (October 2008-July 2010) without meteorological tides. Samples for laboratory analyses were collected from each main river. Multivariate tests by permutations were applied. The period studied was influenced by a drought, within a long period dominated by low flows combined with dry weather and wildfires, and a large (10 years of recurrence) and prolonged (7 months) flood. The hydrological phase, followed by the season and the hydrological year (according to the ENSO event) were the principal explanatory factors of the main water quality changes, whereas the drainage sub-basin and the fluvial environment (river or stream) were secondary explanatory factors. During the drought period, conductivity, turbidity, and associated variables (e.g., major ions, silicon, and iron concentrations) were maximal, whereas real color was minimal. In the overbanking flood phase, pH and dissolved oxygen concentration were minimal, whereas real color was maximal. Dissolved oxygen saturation was also low in the receding flood phase and total major ion load doubled after the arrival of the overbanking stage. The water quality of these watercourses may be affected by the combination of several influences, such as the Paraná River flow, the pulses with sediments and solutes from the Bermejo River, the export of the Delta floodplain properties mainly by the flood, the season, and the saline tributaries to the Lower Paraná River. The high

  14. Practicality of marine protected areas - Can there be solutions for the River Indus delta?

    Science.gov (United States)

    Kidwai, Samina; Fanning, Paul; Ahmed, Waqar; Tabrez, Mohsin; Zhang, Jing; Khan, Muhammad Wasim

    2016-12-01

    The River Indus delta is the most prominent feature on the Pakistan coast. Owing to its prominence, mangrove ecosystem, historical, ecological and economic significance it is also a proposed Marine Protected Area (MPA). Currently there are no designated MPAs in Pakistan. This paper presents findings of the Fishery Resource Appraisal Project of Pakistan (FRAPP) a fishery stock assessment carried out for the pelagic and demersal fishery resource of Pakistan from 2009 to 2015 and the Creek Survey Program (CSP) which was part of FRAPP. And discusses how the delta suffers from physical stress. The observations from FRAPP indicates deterioration in the mangrove ecosystem, that are evident in the form of loss of biodiversity and biological productivity. The 600 observations from 10 major creeks showed that trawl catches were a mix of generally small size fish and shrimp. Catches averaged less than 1 kg per tow in all the creeks sampled. Catch weights were somewhat higher in Isaro, WadiKhuddi, Paitiani, Dabbo, Richaal Creeks all of which were near mangrove areas and open sea. The most frequently occurring species of shrimps caught in the trawls belonged to 7 major taxa. The Khobar Creek and Upper Wari Creek are notable for the high rates of occurrence of every group except the Caridea. They are also the only two creeks where the freshwater family Paleomonidae is common. The size composition of the important penaeid family of shrimps in all study areas combined suggests that the smallest shrimps (0.5-1.5 cm carapace length CL) enter the creeks in February/March and adults (5-6 cm CL) move out again 6-12 months later. Four species of Penaeus (monodon, japonicus, semisulcatus, merguiensis), two species of Metapenaeus (monoceros, affinis), Parapeneoposis stylifera and Solenosera sp. were caught, all in low abundance, less than 0.5 Kg tow-1. The shrimp catches in the area off the Sindh coast, the catches averaged 4.30 ± 13.40 kg h-1 on the inner shelf (20-50 m) and 1.7 ± 6

  15. Distribution and condition of larval and juvenile Lost River and shortnose suckers in the Williamson River Delta restoration project and Upper Klamath Lake, Oregon

    Science.gov (United States)

    Burdick, Summer M.

    2012-01-01

    Federally endangered Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) were once abundant throughout their range but populations have declined. They were extirpated from several lakes in the 1920s and may no longer reproduce in other lakes. Poor recruitment to the adult spawning populations is one of several reasons cited for the decline and lack of recovery of these species and may be the consequence of high mortality during juvenile life stages. High larval and juvenile sucker mortality may be exacerbated by an insufficient quantity of suitable or high-quality rearing habitat. In addition, larval suckers may be swept downstream from suitable rearing areas in Upper Klamath Lake into Keno Reservoir, where they are assumed lost to Upper Klamath Lake populations. The Nature Conservancy flooded about 3,600 acres (1,456 hectares) to the north of the Williamson River mouth (Tulana) in October 2007, and about 1,400 acres (567 hectares) to the south and east of the Williamson River mouth (Goose Bay Farms) in October 2008, in order to retain larval suckers in Upper Klamath Lake, create nursery habitat, and improve water quality. The U.S. Geological Survey joined a long-term research and monitoring program in collaboration with The Nature Conservancy, the Bureau of Reclamation, and Oregon State University in 2008 to assess the effects of the Williamson River Delta restoration on the early life-history stages of Lost River and shortnose suckers. The primary objectives of the research were to describe habitat colonization and use by larval and juvenile suckers and non-sucker fishes and to evaluate the effects of the restored habitat on the health and condition of juvenile suckers. This report summarizes data collected in 2010 by the U.S. Geological Survey as a part of this monitoring effort and follows two annual reports on data collected in 2008 and 2009. Restoration modifications made to the Williamson River Delta appeared to provide

  16. Fire, Carbon, and Greenhouse Gas Emissions from Aquatic Ecosystems in the Yukon-Kuskokwim River Delta

    Science.gov (United States)

    Schade, J. D.; Kuhn, M. A.; Mann, P. J.; Holmes, R. M.; Natali, S.; Ludwig, S.; Wagner, S.

    2016-12-01

    Northern latitudes are experiencing rapid changes in climate that are profoundly altering permafrost-dominated ecosystems. Increased permafrost thaw and fire frequency and severity are changing the structure and function of these ecosystems in ways likely to alter greenhouse gas (GHG) emission, leading to feedbacks on climate that may accelerate warming. Our objective was to investigate changes in GHG emissions and carbon and nitrogen dynamics in aquatic ecosystems in response to recent fires in the Yukon-Kuskokwim river delta in western Alaska. In summer 2015, more area in the YK Delta burned then in the previous 74 years combined (726 km2 in 2015 vs. 477 km2 during 1940-2014). In June of 2016, we sampled water and dissolved gases from a variety of aquatic ecosystems, including small upland ponds and wetlands and streams lower in the landscape, in recently burned and control sites near the Kuka Creek 2015 burn scar in the Yukon Delta National Wildlife Refuge. We measured a range of physical parameters, including water temperature, conductivity, dissolved oxygen, and pH. We also estimated fluxes of CO2 and CH4 from surface waters using a floating chamber connected to a Los Gatos Ultraportable gas analyzer. Water samples were analyzed for dissolved organic carbon (DOC) and total dissolved nitrogen (TDN). Results show reduced DOC concentrations in small upland ponds in burned sites and evidence for loss of DOC downslope in control sites. In contrast, TDN concentration was higher in streams draining burned sites, suggesting fire mobilized N in soils, which was then transported to downslope ecosystems. Furthermore, fire generally increased pH, particularly in small ponds. Finally, we observed 3-4 fold higher CO2 and CH4 fluxes from aquatic ecosystems in burned sites as compared with control sites. We hypothesize that this is due to increased thaw depth and increased pH, which combine to increase resource availability and release methane-producing microbes from the

  17. Temporal fluctuation of multidrug resistant salmonella typhi haplotypes in the mekong river delta region of Vietnam.

    Directory of Open Access Journals (Sweden)

    Kathryn E Holt

    Full Text Available BACKGROUND: typhoid fever remains a public health problem in Vietnam, with a significant burden in the Mekong River delta region. Typhoid fever is caused by the bacterial pathogen Salmonella enterica serovar Typhi (S. Typhi, which is frequently multidrug resistant with reduced susceptibility to fluoroquinolone-based drugs, the first choice for the treatment of typhoid fever. We used a GoldenGate (Illumina assay to type 1,500 single nucleotide polymorphisms (SNPs and analyse the genetic variation of S. Typhi isolated from 267 typhoid fever patients in the Mekong delta region participating in a randomized trial conducted between 2004 and 2005. PRINCIPAL FINDINGS: the population of S. Typhi circulating during the study was highly clonal, with 91% of isolates belonging to a single clonal complex of the S. Typhi H58 haplogroup. The patterns of disease were consistent with the presence of an endemic haplotype H58-C and a localised outbreak of S. Typhi haplotype H58-E2 in 2004. H58-E2-associated typhoid fever cases exhibited evidence of significant geo-spatial clustering along the Sông H u branch of the Mekong River. Multidrug resistance was common in the established clone H58-C but not in the outbreak clone H58-E2, however all H58 S. Typhi were nalidixic acid resistant and carried a Ser83Phe amino acid substitution in the gyrA gene. SIGNIFICANCE: the H58 haplogroup dominates S. Typhi populations in other endemic areas, but the population described here was more homogeneous than previously examined populations, and the dominant clonal complex (H58-C, -E1, -E2 observed in this study has not been detected outside Vietnam. IncHI1 plasmid-bearing S. Typhi H58-C was endemic during the study period whilst H58-E2, which rarely carried the plasmid, was only transient, suggesting a selective advantage for the plasmid. These data add insight into the outbreak dynamics and local molecular epidemiology of S. Typhi in southern Vietnam.

  18. Intercomparison study of atmospheric methane and carbon dioxide concentrations measured at the Ebre River Delta Station

    Science.gov (United States)

    Occhipinti, Paola; Morguí, Josep Anton; Àgueda, Alba; Batet, Oscar; Borràs, Sílvia; Cañas, Lídia; Curcoll, Roger; Grossi, Claudia; Nofuentes, Manel; Vazquez, Eusebi; Rodó, Xavier

    2015-04-01

    In the framework of the ClimaDat project, IC3 has established a network of eight monitoring stations across the Iberian Peninsula and the Canarian Archipelago with the aim of studying climate processes. The monitoring station at the Ebre River Delta (DEC3) is located in the Ebre River Delta Natural Park (40° 44' N; 0° 47' E) and it is characterized by the typical North-Western Mediterranean climate. Since 2013, atmospheric greenhouse gases (GHG) and 222Rn tracer gas together with the meteorological parameters are continuously measured from a 10 m a.g.l. height tower. Atmospheric GHG (CO2, CH4, CO and N2O) concentrations are determined using a Picarro analyzer G2301 (CO2 and CH4) and a modified gas chromatograph (GC) Agilent 6890N (CO2, CH4, CO and N2O). Open data access is available from the www.climadat.es website. Data collected at the DEC3 station are also submitted to the InGOS platform since this station is part of the InGOS European infrastructure project. Researchers from the Laboratory of the Atmosphere and the Oceans (LAO) at IC3 have performed an intercomparison study at the DEC3 site between three different Picarro analyzers (two Picarro G2301 and one Picarro G2301M), a Los Gatos Research (LGR) analyzer and the GC system already installed at the station. The aim of this study is to compare and assess the measuring agreement between the four optical gas analyzers and the GC. In the first part of the experiment, all instruments have been calibrated using NOAA gases as primary standards analyzing five Praxair provided targets to evaluate the precision of the measuring instruments. Max Plank Institute (MPI) gases have been used as secondary standards for the GC whereas Praxair provided tanks are used as secondary standards for the Picarro and the LGR analyzers. In the second part of the experiment, atmospheric GHG were measured from natural atmospheric air taken from a 10 m a.g.l. inlet. Daily cycles of GHG measurements were carried out using different

  19. Absorption coefficient of urban aerosol in Nanjing, west Yangtze River Delta of China

    Directory of Open Access Journals (Sweden)

    B. L. Zhuang

    2015-06-01

    Full Text Available Absorbing aerosols can significantly modulate shortwave solar radiation in the atmosphere, affecting regional and global climate. Aerosol absorption coefficient (AAC is an indicator to assess the impact of absorbing aerosols on radiative forcing. In this study, the near-surface AAC and absorption angstrom exponent (AAE in urban Nanjing, China, are characterized on the basis of measurements in 2012 and 2013 using the 7-channel Aethalometer (model AE-31, Magee Scientific, USA. The AAC is estimated with direct and indirect corrections, which show consistent temporal variations and magnitudes of AAC at 532 nm. The mean AAC at 532 nm is about 43.23 ± 28.13 M m−1 in urban Nanjing, which is much lower than that in Pearl River Delta and as the same as that in rural areas (Lin'an in Yangtze River Delta. The AAC in urban Nanjing shows strong seasonality (diurnal variations, high in cold seasons (at rush hours and low in summer (in afternoon. It also show synoptic and quasi-two-week cycles in response to weather systems. Its frequency distribution follows a typical lognormal pattern. The 532 nm-AAC ranging from 15 to 65 M m−1 dominates, accounting for more than 72% of the total data samples in the entire study period. Frequent high pollution episodes, such as those observed in June 2012 and in winter 2013, greatly enhanced AAC and altered its temporal variations and frequency distributions. These episodes are mostly due to local emissions and regional pollutions. Air masses from northern China to Nanjing can sometimes be highly polluted and lead to high AAC at the site. AAE at 660/470 nm from the Schmid correction (Schmid et al., 2006 is about 1.56, which might be more reasonable compared to that from the Weingartner correction (Weingartner et al., 2003. Low AAEs mainly appear in summer in response to the relative humidity (RH. AAC increases with increasing AAE at a fixed aerosol loading. The RH-AAC relationship is more complex. Overall, AAC peaks

  20. Spatial and Seasonal Variations of Total Petroleum Hydrocarbon in Surface Water and Sediment in Pearl River Delta.

    Science.gov (United States)

    Zhao, Jiandi; Yin, Pinghe; Zhao, Ling; Yu, Qiming; Lu, Gang

    2015-09-01

    A field study in the Pearl River Delta of China was conducted in order to describe to the spatial and seasonal variation of occurrence and concentrations of total petroleum hydrocarbon (TPH) in surface water and sediments. Petroleum hydrocarbons and isoprenoid alkanes were quantified by UV spectroscopy and gas chromatography with a mass selective detector. The concentrations of TPH ranged from 4.3 to 68.7 µg L(-1) in surface water, and from 66.6 to 1445 µg g(-1) in surface sediments. The ratios of pristine to phytane suggested that the main sources of TPH in the sediment were petroleum importation. The highest concentrations of TPH were present in the spring season. When compared with results from previous studies, it can be concluded that the Pearl River Delta was moderately polluted by TPH. No statistically significant correlations were observed between the concentrations of TPH in surface water and sediments.

  1. Greater Than The Sum of Its Parts:Building Up A Co-operative Database of Pearl River Delta Collection

    Institute of Scientific and Technical Information of China (English)

    PaulW.T.Poon; Ph.D.,F.L.A

    1994-01-01

    This paper starts with a brief description of what a database is followed by a short history of the development of the database system and its use; it also notes the proliferation of various kinds of databases in the 1990s. It then goes on to outline the background of establishing a Pearl River Delta Collection at the City University of Hong Kong and the Hong Kong Lingnan College. One of the tasks in this project is to build up a database of Pearl River Delta-related materials available in all the UPGC(University and Polytechnic Grant Committee)libraries in Hong Kong. The database design and structure are described, and the problems associated with data collection, source data, and updating together with their solutions are explained.

  2. Emission inventory of anthropogenic air pollutants and VOC species in the Yangtze River Delta region, China

    Directory of Open Access Journals (Sweden)

    C. Huang

    2011-05-01

    Full Text Available The purpose of this study is to develop an emission inventory for major anthropogenic air pollutants and VOC species in the Yangtze River Delta (YRD region for the year 2007. A "bottom-up" methodology was adopted to compile the inventory based on major emission sources in the sixteen cities of this region. Results show that the emissions of SO2, NOx, CO, PM10, PM2.5, VOCs, and NH3 in the YRD region for the year 2007 are 2392 kt, 2293 kt, 6697 kt, 3116 kt, 1511 kt, 2767 kt, and 459 kt, respectively. Ethylene, mp-xylene, o-xylene, toluene, 1,2,4-trimethylbenzene, 2,4-dimethylpentane, ethyl benzene, propylene, 1-pentene, and isoprene are the key species contributing 77 % to the total ozone formation potential (OFP. The spatial distribution of the emissions shows the emissions and OFPs are mainly concentrated in the urban and industrial areas along the Yangtze River and around Hangzhou Bay. The industrial sources, including power plants other fuel combustion facilities, and non-combustion processes contribute about 97 %, 86 %, 89 %, 91 %, and 69 % of the total SO2, NOx, PM10, PM2.5, and VOC emissions. Vehicles take up 12.3 % and 12.4 % of the NOx and VOC emissions, respectively. Regarding OFPs, the chemical industry, domestic use of paint & printing, and gasoline vehicles contribute 38 %, 24 %, and 12 % to the ozone formation in the YRD region.

  3. Sectorial water use trends in the urbanizing Pearl River Delta, China.

    Directory of Open Access Journals (Sweden)

    Mingtian Yao

    Full Text Available Assessing and managing water use is crucial for supporting sustainable river basin management and regional development. The first consistent and comprehensive assessment of sectorial water use in the Pearl River Delta (PRD is presented by analysing homogenized annual water use data from 2000 to 2010 in relation to socio economic statistics for the same period. An abstraction of water use, using the concept of water use intensity, and based on equations inspired by those used in global water resource models, is developed to explore the driving forces underlying water use changes in domestic, industrial and agricultural sectors. We do this at both the level of the region as a whole, as well as for the nine cities that constitute the PRD separately. We find that, despite strong population and economic growth, the PRD managed to stabilize its absolute water use by significant improvements in industrial water use intensities, and early stabilisation of domestic water use intensities. Results reveal large internal differentiation of sectorial water use among the cities in this region, with industrial water use intensity varying from -80 to +95% and domestic water use intensity by +/- 30% compared to the PRD average. In general, per capita water use is highest in the cities that industrialised first. Yet, all cities except Guangzhou are expected to approach a saturation value of per capita water use much below what is suggested in recent global studies. Therefore, existing global assessments probably have overestimated future domestic water use in developing countries. Although scarce and uncertain input data and model limitations lead to a high level of uncertainty, the presented conceptualization of water use is useful in exploring the underlying driving forces of water use trends.

  4. Cost analysis of water and sediment diversions to optimize land building in the Mississippi River delta

    Science.gov (United States)

    Kenney, Melissa A.; Hobbs, Benjamin F.; Mohrig, David; Huang, Hongtai; Nittrouer, Jeffrey A.; Kim, Wonsuck; Parker, Gary

    2013-06-01

    Land loss in the Mississippi River delta caused by subsidence and erosion has resulted in habitat loss and increased exposure of settled areas to storm surge risks. There is debate over the most cost-efficient and geomorphologically feasible projects to build land by river diversions, namely, whether a larger number of small, or a lesser number of large, engineered diversions provide the most efficient outcomes. This study uses an optimization framework to identify portfolios of diversions that are efficient for three general restoration objectives: maximize land built, minimize cost, and minimize water diverted. The framework links the following models: (1) a hydraulic water and sediment diversion model that, for a given structural design for a diversion, estimates the volume of water and sediment diverted; (2) a geomorphological land-building model that estimates the amount of land built over a time period, given the volume of water and sediment; and (3) a statistical model of investment cost as a function of diversion depth and width. An efficient portfolio is found by optimizing one objective subject to constraints on achievement of the other two; then by permuting those constraints, we find distinct portfolios that represent trade-offs among the objectives. Although the analysis explores generic relationships among size, cost, and land building (and thus does not consider specific project proposals or locations), the results demonstrate that large-scale land building (>200 km2) programs that operate over a time span of 50 years require deep diversions because of the enhanced efficiency of sand extraction per unit water. This conclusion applies whether or not there are significant scale economies or diseconomies associated with wider and deeper diversions.

  5. Sectorial water use trends in the urbanizing Pearl River Delta, China.

    Science.gov (United States)

    Yao, Mingtian; Werners, Saskia E; Hutjes, Ronald W A; Kabat, Pavel; Huang, Heqing

    2015-01-01

    Assessing and managing water use is crucial for supporting sustainable river basin management and regional development. The first consistent and comprehensive assessment of sectorial water use in the Pearl River Delta (PRD) is presented by analysing homogenized annual water use data from 2000 to 2010 in relation to socio economic statistics for the same period. An abstraction of water use, using the concept of water use intensity, and based on equations inspired by those used in global water resource models, is developed to explore the driving forces underlying water use changes in domestic, industrial and agricultural sectors. We do this at both the level of the region as a whole, as well as for the nine cities that constitute the PRD separately. We find that, despite strong population and economic growth, the PRD managed to stabilize its absolute water use by significant improvements in industrial water use intensities, and early stabilisation of domestic water use intensities. Results reveal large internal differentiation of sectorial water use among the cities in this region, with industrial water use intensity varying from -80 to +95% and domestic water use intensity by +/- 30% compared to the PRD average. In general, per capita water use is highest in the cities that industrialised first. Yet, all cities except Guangzhou are expected to approach a saturation value of per capita water use much below what is suggested in recent global studies. Therefore, existing global assessments probably have overestimated future domestic water use in developing countries. Although scarce and uncertain input data and model limitations lead to a high level of uncertainty, the presented conceptualization of water use is useful in exploring the underlying driving forces of water use trends.

  6. Benthic sediment data from eleven stations in the Mobile-Tensaw River Delta, Alabama on 17 June 1981 (NODC Accession 0118497)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic sediment samples were collected from eleven stations in the Mobile-Tensaw River Delta on 17 June 1981. Samples were analyzed for particle size distribution...

  7. Report to Pacific Flyway Study Committee on 1986-1991 breeding ground surveys of dusky Canada geese on the Copper River Delta

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Development of an expanded aerial survey on the Copper River Delta was begun in 1985. survey design was standardized in 1988 and the same transects have been flown...

  8. Report to Pacific Flyway Study Committee on 1986-1994 breeding ground surveys of Dusky Canada geese on the Copper River Delta

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Development of an expanded aerial survey on the Copper River Delta was begun in 1986. Survey design was standardized in 1988 and the same transects have been flown...

  9. Assessing subaqueous mudslide hazard on the Mississippi River delta front, Part 2: Insights revealed through high-resolution geophysical surveying

    Science.gov (United States)

    Obelcz, J.; Xu, K.; Bentley, S. J.; Georgiou, I. Y.; Maloney, J. M.; Miner, M. D.; Hanegan, K.; Keller, G.

    2014-12-01

    The northern Gulf of Mexico, including the subaqueous Mississippi River delta front (MRDF), has been productive for oil and gas development since the early 1900s. In 1969 cyclic seafloor wave loading associated with the passage of Hurricane Camille triggered subaqueous mudflows across the MRDF, destroying several offshore oil platforms. This incident spurred geophysical and geotechnical studies of the MRDF, which found that the delta front is prone to mass failures on gentle gradients (survey area can be classified into four primary sedimentary facies: mudflow gullies, mudflow lobes, undisturbed prodelta, and undisturbed delta front. Subbottom profiles reveal extensive biogenic gas from 20 to about 80 m water depths on the delta front; sidescan data show a variety of bottleneck slides, mudflow gullies and mudflow noses. Previous studies have attempted to constrain the periodicity and magnitude of subaqueous mudslides on the MRDF. However, large age gaps and varied resolution between datasets result in ambiguity regarding the cause and magnitude of observed bathymetric changes. We present high-temporal resolution MRDF bathymetric variations from 2005 (post Hurricane Katrina), 2009 (relatively quiescent storm period), and 2014 (post 2011 Mississippi River flood). These data yield better magnitude and timing estimates of mass movements. This exercise represents a first step towards (1) assembling a comprehensive geologic dataset upon which future MRDF geohazard assessments can be founded, and (2) understanding the dynamics of a massive passive margin deltaic lobe entering a phase of decline.

  10. Prediction and prevention of the impacts of sea level rise on the Yangtze River Delta and its adjacent areas

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Yangtze River Delta region is characterized by high density of population and rapidly developing economy. There are low lying coastal plain and deltaic plain in this region. Thus, the study area could be highly vulnerable to accelerated sea level rise caused by global warming. This paper deals with the scenarios of the relative sea level rise in the early half period of the 21st century in the study area. The authors suggested that relative sea level would rise 25 50 cm by the year 2050 in the study area, of which the magnitude of relative sea level rise in the Yangtze River Delta would double the perspective worldwide average. The impacts of sea level rise include: (i) exacerbation of coastline recession in several sections and vertical erosion of tidal flat, and increase in length of eroding coastline; (ii) decrease in area of tidal flat and coastal wetland due to erosion and inundation; (iii) increase in frequency and intensity of storm surge, which would threaten the coastal protection works; (iv) reduction of drainage capacity due to backwater effect in the Lixiahe lowland and the eastern lowland of Taihu Lake region, and exacerbation of flood and waterlogging disasters; and (v) increase in salt water intrusion into the Yangtze Estuary. Comprehensive evaluation of sea level rise impacts shows that the Yangtze River Delta and eastern lowland of Taihu Lake region, especially Shanghai Municipality, belong in the district in the extreme risk category and the next is the northern bank of Hangzhou Bay, the third is the abandoned Yellow River delta, and the district at low risk includes the central part of north Jiangsu coastal plain and Lixiahe lowland.

  11. Public health and medical care for the world's factory: China's Pearl River Delta Region

    Directory of Open Access Journals (Sweden)

    Rodwin Victor G

    2011-10-01

    Full Text Available Abstract While the growth of urbanization, worldwide, has improved the lives of migrants from the hinterland, it also raises health risks related to population density, concentrated poverty and the transmission of infectious disease. Will megacity regions evolve into socially infected breeding grounds for the rapid transmission of disease, or can they become critical spatial entities for the protection and promotion of population health? We address this question for the Pearl River Delta Region (PRD based on recent data from Chinese sources, and on the experience of how New York, Greater London, Tokyo and Paris have grappled with the challenges of protecting population health and providing their populations with access to health care services. In some respects, there are some important lessons from comparative experience for PRD, notably the importance of covering the entire population for health care services and targeting special programs for those at highest risk for disease. In other respects, PRD's growth rate and sheer scale make it a unique megacity region that already faces new challenges and will require new solutions.

  12. Volatile Organic Compound (VOC measurements in the Pearl River Delta (PRD region, China

    Directory of Open Access Journals (Sweden)

    Chih-chung Chang

    2008-03-01

    Full Text Available We measured levels of ambient volatile organic compounds (VOCs at seven sites in the Pearl River Delta (PRD region of China during the Air Quality Monitoring Campaign spanning 4 October to 3 November 2004. Two of the sites, Guangzhou (GZ and Xinken (XK, were intensive sites at which we collected multiple daily canister samples. The observations reported here provide a look at the VOC distribution, speciation, and photochemical implications in the PRD region. Alkanes constituted the largest percentage (>40% in mixing ratios of the quantified VOCs at six sites; the exception was one major industrial site that was dominated by aromatics (about 52%. Highly elevated VOC levels occurred at GZ during two pollution episodes; however, the chemical composition of VOCs did not exhibit noticeable changes during these episodes. We calculated the OH loss rate to estimate the chemical reactivity of all VOCs. Of the anthropogenic VOCs, alkenes played a predominant role in VOC reactivity at GZ, whereas the contributions of reactive aromatics were more important at XK. Our preliminary analysis of the VOC correlations suggests that the ambient VOCs at GZ came directly from local sources (i.e., automobiles; those at XK were influenced by both local emissions and transportation of air mass from upwind areas.

  13. Delaying precipitation by air pollution over the Pearl River Delta: 2. Model simulations

    Science.gov (United States)

    Lee, Seoung Soo; Guo, Jianping; Li, Zhanqing

    2016-10-01

    In Part 1 of two companion studies, analyses of observational data over the Pearl River Delta of China showed that larger aerosol concentrations (polluted conditions) resulted in suppressed precipitation before the midafternoon while resulting in enhanced precipitation after the midafternoon when compared to precipitation with smaller aerosol concentrations (clean conditions). This suggests that there is a tipping point in the transition from suppressing to enhancing precipitation with increases in aerosol concentration. This paper aims to identify mechanisms that control the tipping point by performing simulations. Simulations show that during the first three quarters of the 12 h simulation period, aerosol as a radiation absorber suppresses convection and precipitation by inducing greater radiative heating and stability. Convection weakens and precipitation reduces more under polluted conditions than under clean conditions. Due to the suppressed convection, the depletion of convective energy decreases. The reduced depletion of convective energy during the period of the suppressed convection boosts the level of stored energy after this period. The boosted level of stored energy enables updrafts to be strong enough to transport a greater amount of cloud liquid to the freezing level and to levels above it under polluted conditions than under clean conditions. This in turn induces greater freezing-related latent heating, buoyancy, and thus stronger convection and results in the transition from lower precipitation rates during the first three quarters of the simulation period to higher precipitation rates during the last quarter of the period under polluted conditions than under clean conditions.

  14. ENVIRONMENTAL CHANGE AND ITS IMPACTS ON HUMAN SETTLEMENT IN THE CHANGJIANG RIVER DELTA IN NEOLITHIC AGE

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qiang; LIU Chun-ling; ZHU Cheng; JIANG Tong

    2004-01-01

    Dating data,altitude of Neolithic sites,climatic changes from sedimentary records and previous research results were collected and analyzed to detect possible connections between climatic changes and human activities in the Changjiang River Delta in the Neolithic Age.The results indicated that hydrological changes greatly impacted the human activities in the study region.Low-lying geomorphology made the floods and sea level changes become the important factors affecting human activities,especially the altitude change of human settlements.People usually moved to higher places during the periods characterized by high sea level and frequent floods to escape the negative influences from water body expansion,which resulted in cultural hiatus in certain profiles.However,some higher-altitude settlements were not the results of climatic changes but the results of social factors,such as religious ceremony and social status.Therefore,further research will be necessary for the degree and types of impacts of climatic changes on human activities in the study area at that time.

  15. Source apportionment and health effect of NOx over the Pearl River Delta region in southern China.

    Science.gov (United States)

    Lu, Xingcheng; Yao, Teng; Li, Ying; Fung, Jimmy C H; Lau, Alexis K H

    2016-05-01

    As one of the most notorious atmospheric pollutants, NOx not only promotes the formation of ozone but also has adverse health effects on humans. It is therefore of great importance to study the sources of NOx and its effects on human health. The Comprehensive Air Quality Model (CAMx) modeling system and ozone source apportionment technology (OSAT) were used to study the contribution of NOx from different emission sources over southern China. The results indicate that heavy duty diesel vehicles (HDDVs) and industrial point sources are the two major local NOx sources, accounting for 30.8% and 18.5% of local NOx sources, respectively. In Hong Kong, marine emissions contributed around 43.4% of local NOx in 2011. Regional transport is another important source of this pollutant, especially in February and November, and it can contribute over 30% of ambient NOx on average. Power plant point emission is an significant regional source in Zhuhai, Zhongshan and Foshan. The total emission sources are estimated to cause 2119 (0-4405) respiratory deaths and 991 (0-2281) lung cancer deaths due to long-term exposure to NOx in the Pearl River Delta region. Our results suggest that local governments should combine their efforts and vigorously promote further reduction of NOx emissions, especially for those sources that make a substantial contribution to NOx emissions and affect human health: HDDV, LDGV, industrial point sources and marine sources.

  16. [Formation causes of wind damage to Robinia pseudoacacia plantation in Yellow River Delta].

    Science.gov (United States)

    Cao, Bang-Hua; Zhang, Yu-Juan; Mao, Pei-Li; Li, Cheng-Bo

    2012-08-01

    Based on the investigation of the gale-caused damage to the Robinia pseudoacacia plantation in the Yellow River Delta in June-July 2010, this paper measured the morphological indexes and root system characteristics of fallen trees, gap sizes, and soil compactness, aimed to analyze the formation causes of the wind damage to the plantation. Wind-falling was the main form of the wind damage to the R. pseudoacacia plantation, and the damage was more serious for the trees with the diameter at breast height of 15-20 cm. For the fallen trees, their tree height and their crown width, height, and taper degree increased significantly with the increase of the diameter at breast height, while the height under branch, the ratio of crown width to height, and the ratio of the height under branch to tree height showed no significant change. With the increase of diameter class, root length had a rapid increase first but a slow increase then, while root mass increased gradually. With increasing forest gap area, the number of fallen trees decreased after an initial increase, being the maximum in the gap areas of 100-150 m2. Soil compactness increased with soil depth, but did not show significant changes with the stand diameter class. Increased tree shape factors and suppressed root growth resulting from the increased diameter could be the main factors causing wind-falling, and forest gap played a promotion role.

  17. Delaying precipitation and lightning by air pollution over the Pearl River Delta. Part I: Observational analyses

    Science.gov (United States)

    Guo, Jianping; Deng, Minjun; Lee, Seoung Soo; Wang, Fu; Li, Zhanqing; Zhai, Panmao; Liu, Huan; Lv, Weitao; Yao, Wen; Li, Xiaowen

    2016-06-01

    The radiative and microphysical effects of aerosols can affect the development of convective clouds. The objective of this study is to reveal if the overall aerosol effects have any discernible impact on the diurnal variations in precipitation and lightning by means of both observational analysis and modeling. As the first part of two companion studies, this paper is concerned with analyzing hourly PM10, precipitation, and lightning data collected during the summers of 2008-2012 in the Pearl River Delta region. Daily PM10 data were categorized as clean, medium, or polluted so that any differences in the diurnal variations in precipitation and lightning could be examined. Heavy precipitation and lightning were found to occur more frequently later in the day under polluted conditions than under clean conditions. Analyses of the diurnal variations in several meteorological factors such as air temperature, vertical velocity, and wind speed were also performed. They suggest that the influence of aerosol radiative and microphysical effects serve to suppress and enhance convective activities, respectively. Under heavy pollution conditions, the reduction in solar radiation reaching the surface delays the occurrence of strong convection and postpones heavy precipitation to late in the day when the aerosol invigoration effect more likely comes into play. Although the effect of aerosol particles can be discernible on the heavy precipitation through the daytime, the influence of concurrent atmospheric dynamics and thermodynamics cannot be ruled out.

  18. Spatial-temporal distribution of phthalate esters from riverine outlets of Pearl River Delta in China.

    Science.gov (United States)

    Li, Ting; Yin, Pinghe; Zhao, Ling; Wang, Guifang; Yu, Qiming Jimmy; Li, Huanyong; Duan, Shunshan

    2015-01-01

    The aquatic environments of the Pearl River Delta (PRD) in China have been contaminated by various industrial chemicals from local industries. In this study, the spatial-temporal distribution of six priority phthalate esters (PAEs) in surface water and sediments from the PRD was investigated. The PAEs were detected with total concentrations (Σ6PAEs) ranging from 0.35 to 20.70 μg L⁻¹ in surface water and dry weight ranging from 0.88 to 5.69 μg g⁻¹ in sediments. The Σ6PAEs concentrations in surface water were higher in the wet season than those in the dry season, while the opposite pattern was observed in sediments. Di(2-ethylhexyl) phthalate (DEHP) was the most abundant congener, which was higher than those reported in the literature. Risk quotients for relevant aquatic organisms were obtained and showed that most of these PAEs, in particular, butyl benzyl phthalate, DEHP and di-n-octyl phthalate, have significant potential health and ecological risks for the aquatic environment studied.

  19. Humpback Dolphins in Hong Kong and the Pearl River Delta: Status, Threats and Conservation Challenges.

    Science.gov (United States)

    Karczmarski, Leszek; Huang, Shiang-Lin; Or, Carmen K M; Gui, Duan; Chan, Stephen C Y; Lin, Wenzhi; Porter, Lindsay; Wong, Wai-Ho; Zheng, Ruiqiang; Ho, Yuen-Wa; Chui, Scott Y S; Tiongson, Angelico Jose C; Mo, Yaqian; Chang, Wei-Lun; Kwok, John H W; Tang, Ricky W K; Lee, Andy T L; Yiu, Sze-Wing; Keith, Mark; Gailey, Glenn; Wu, Yuping

    2016-01-01

    In coastal waters of the Pearl River Delta (PRD) region, the Indo-Pacific humpback dolphin (Sousa chinensis) is thought to number approximately 2500 individuals. Given these figures, the putative PRD population may appear strong enough to resist demographic stochasticity and environmental pressures. However, living in close proximity to the world's busiest seaport/airport and several densely populated urban centres with major coastal infrastructural developments comes with challenges to the long-term survival of these animals. There are few other small cetacean populations that face the range and intensity of human-induced pressures as those present in the PRD and current protection measures are severely inadequate. Recent mark-recapture analyses of the animals in Hong Kong waters indicate that in the past two decades the population parameters have not been well understood, and spatial analyses show that only a very small proportion of the dolphins' key habitats are given any form of protection. All current marine protected areas within the PRD fail to meet a minimum habitat requirement that could facilitate the population's long-term persistence. Demographic models indicate a continuous decline of 2.5% per annum, a rate at which the population is likely to drop below the demographic threshold within two generations and lose 74% of the current numbers within the lifespan of three generations. In Hong Kong, the case of humpback dolphins represents a particularly explicit example of inadequate management where a complete revision of the fundamental approach to conservation management is urgently needed.

  20. An ozone episode over the Pearl River Delta in October 2008

    Science.gov (United States)

    Shen, Jin; Zhang, Yuanhang; Wang, Xuesong; Li, Jinfeng; Chen, Hao; Liu, Run; Zhong, Liuju; Jiang, Ming; Yue, Dingli; Chen, Duohong; Lv, Wei

    2015-12-01

    The north and east Pearl River Delta (PRD) is usually a clean, upwind area in autumn. Serious ozone pollution there in mid-late October 2008 was first discovered and then analyzed. Trajectory analysis, process analysis, ozone source apportionment technology, and sensitivity analysis were used to study this episode. Under the influence of a weak south wind, the precursors emitted in Guangzhou and Foshan were transported to the north and northeast PRD and formed ozone there, which resulted in high ozone concentration (>100 ppb). As the wind direction later transited to northerly, the precursors in the northeast PRD that originated from the central and west PRD were transported to the south, and caused severe ozone pollution in the southeast PRD. The ozone contributed by chemical processes reached >20 ppb/h in Jinguowan. More than 40 ppb ozone was contributed by the precursor emission in the central and west PRD during the episode. The ozone concentration was highly sensitive to the precursor emission in the PRD region in the high-ozone situations. This episode showed the complexity of regional pollution in the PRD. When the PRD is controlled by a low air pressure system and then cold air moves from northern China to the south, the risk of ozone pollution in the north and southeast PRD increases.

  1. Foraging and growth potential of juvenile Chinook Salmon after tidal restoration of a large river delta

    Science.gov (United States)

    David, Aaron T.; Ellings, Christopher; Woo, Isa; Simenstad, Charles A.; Takekawa, John Y.; Turner, Kelley L.; Smith, Ashley L.; Takekawa, Jean E.

    2014-01-01

    We evaluated whether restoring tidal flow to previously diked estuarine wetlands also restores foraging and growth opportunities for juvenile Chinook Salmon Oncorhynchus tshawytscha. Several studies have assessed the value of restored tidal wetlands for juvenile Pacific salmon Oncorhynchus spp., but few have used integrative measures of salmon performance, such as habitat-specific growth potential, to evaluate restoration. Our study took place in the Nisqually River delta, Washington, where recent dike removals restored tidal flow to 364 ha of marsh—the largest tidal marsh restoration project in the northwestern contiguous United States. We sampled fish assemblages, water temperatures, and juvenile Chinook Salmon diet composition and consumption rates in two restored and two reference tidal channels during a 3-year period after restoration; these data were used as inputs to a bioenergetics model to compare Chinook Salmon foraging performance and growth potential between the restored and reference channels. We found that foraging performance and growth potential of juvenile Chinook Salmon were similar between restored and reference tidal channels. However, Chinook Salmon densities were significantly lower in the restored channels than in the reference channels, and growth potential was more variable in the restored channels due to their more variable and warmer (2°C) water temperatures. These results indicate that some—but not all—ecosystem attributes that are important for juvenile Pacific salmon can recover rapidly after large-scale tidal marsh restoration.

  2. The inhabited environment, infrastructure development and advanced urbanization in China’s Yangtze River Delta Region

    Science.gov (United States)

    Zhu, Xiaoqing; Gao, Weijun; Zhou, Nan; Kammen, Daniel M.; Wu, Yiqun; Zhang, Yao; Chen, Wei

    2016-12-01

    This paper analyzes the relationship among the inhabited environment, infrastructure development and environmental impacts in China’s heavily urbanized Yangtze River Delta region. Using primary human environment data for the period 2006-2014, we examine factors affecting the inhabited environment and infrastructure development: urban population, GDP, built-up area, energy consumption, waste emission, transportation, real estate and urban greenery. Then we empirically investigate the impact of advanced urbanization with consideration of cities’ differences. Results from this study show that the growth rate of the inhabited environment and infrastructure development is strongly influenced by regional development structure, functional orientations, traffic network and urban size and form. The effect of advanced urbanization is more significant in large and mid-size cities than huge and mega cities. Energy consumption, waste emission and real estate in large and mid-size cities developed at an unprecedented rate with the rapid increase of economy. However, urban development of huge and mega cities gradually tended to be saturated. The transition development in these cities improved the inhabited environment and ecological protection instead of the urban construction simply. To maintain a sustainable advanced urbanization process, policy implications included urban sprawl control polices, ecological development mechanisms and reforming the economic structure for huge and mega cities, and construct major cross-regional infrastructure, enhance the carrying capacity and improvement of energy efficiency and structure for large and mid-size cities.

  3. The Relationship between Urban Sprawl and Farmland Displacement in the Pearl River Delta, China

    Directory of Open Access Journals (Sweden)

    Shiqiang Du

    2013-12-01

    Full Text Available China is rapidly urbanizing and will inevitably face trade-offs between promoting economic growth through further urbanization and protecting fertile farmland against accelerated urban expansion. This paper presents how this dilemma is being addressed in one of the most rapidly urbanizing regions in China, the Pearl River Delta (PRD, by means of assessing urban growth and farmland dynamic, as well as their complex relationships. Land use maps derived from Landsat imagery for 1990, 2000 and 2010 show a process of accelerated urban sprawl whereby built-up lands have more than quadrupled and scattered centers have merged into megacities. Nonetheless, the land use efficiency is considerably low and is declining relative to Hong Kong and Macau with respect to urban population density. On the other hand, the spreading of urban areas on farmlands causes new farmland reclamation and accelerated deforestation in the hilly surroundings. In addition, the displaced farmlands do not ensure food production because of both reclaiming farmlands on infertile lands and diversifying farming activities from grain production to market-oriented ones. The accelerated urbanization and farmland displacement are driven by profit-oriented development strategy and ineffective land use planning. Our findings demonstrate how spatial analysis can help to investigate the integrated effects of land policies on landscape.

  4. VOCs and OVOCs distribution and control policy implications in Pearl River Delta region, China

    Science.gov (United States)

    Louie, Peter K. K.; Ho, Josephine W. K.; Tsang, Roy C. W.; Blake, Donald R.; Lau, Alexis K. H.; Yu, Jian Zhen; Yuan, Zibing; Wang, Xinming; Shao, Min; Zhong, Liuju

    2013-09-01

    Ambient air measurements of volatile organic compounds (VOCs) and oxygenated volatile organic compounds (OVOCs) were conducted and characterised during a two-year grid study in the Pearl River Delta (PRD) region of southern China. The present grid study pioneered the systematic investigation of the nature and characteristics of complex VOC and OVOC sources at a regional scale. The largest contributing VOCs, accounting over 80% of the total VOCs mixing ratio, were toluene, ethane, ethyne, propane, ethene, butane, benzene, pentane, ethylbenzene, and xylenes. Sub-regional VOC spatial characteristics were identified, namely: i) relatively fresh pollutants, consistent with elevated vehicular and industrial activities, around the PRD estuary; and ii) a concentration gradient with higher mixing ratios of VOCs in the west as compared with the eastern part of PRD. Based on alkyl nitrate aging determination, a high hydroxyl radical (OH) concentration favoured fast hydrocarbon reactions and formation of locally produced ozone. The photochemical reactivity analysis showed aromatic hydrocarbons and alkenes together consisted of around 80% of the ozone formation potential (OFP) among the key VOCs. We also found that the OFP from OVOCs should not be neglected since their OFP contribution was more than one-third of that from VOCs alone. These findings support the choice of current air pollution control policy which focuses on vehicular sources but warrants further controls. Industrial emissions and VOCs emitted by solvents should be the next targets for ground-level ozone abatement.

  5. Coordinated Development between Urban Tourism Economy and Transport in the Pearl River Delta, China

    Directory of Open Access Journals (Sweden)

    Qiuxia Zheng

    2016-12-01

    Full Text Available By selecting the panel data from 2005 to 2014 of 9 cities in the Pearl River Delta (PRD in China, this paper respectively establishes the evaluation index system of tourism economy and transport. It also applies a synthetic evaluation model and coupling coordination model to estimate comprehensive indices of tourism economy and transport system and their coordinated relationships. The results show that: (1 during 2005–2014, the synthetic indices of tourism economy generally presented constantly upward tendency and the synthetic indices of transport represented wave-like raising trend in the PRD region; (2 during 2005–2014, the 9 cities in the PRD region gradually tended to have coordinated development between tourism economy and transport, and the central area of the PRD region developed faster than the flanks; (3 the correlations between the tourism economy and transport of the cities with abundant tourism resources, developed economy, and advanced transport facilities were more remarkable, and the coordination degrees were higher. Besides, macro-policies, mega-events, and locations also impacted on coordinated development between the tourism economy and transport in the PRD region.

  6. Spatial and environmental effects on plant communities in the Yellow River Delta, Eastern China

    Institute of Scientific and Technical Information of China (English)

    SONG Chuang-ye; LIU Gao-huan; LIU Qing-sheng

    2009-01-01

    Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspondence analyses (DCCAs) and a two-way indicator species analysis (TWINSPAN). The distribution pattern and influential factors of the plant communities were also analyzed by testing elevation, slope, soil characteristics, longitude and latitude of 134 vegetation samples collected by representative plot sampling methods. Results showed that all the 134 vegetation samples could be divided into seven vegetation groups, separately dominated by Robinia pseucdoacacia, Imperata cylindrical, Miscanthus saccharifleus, Suaeda salsa, Aeluropus sinensis, Phragmites australis and Tamarix chinensis. The vegetation distribution pattern was mainly related to elevation, ground water depth and soil characteristics such as salinity and soluble potassium. Among the factors affecting distribution pattern of the plant communities, the species matrix explained by non-spatial environmental variation accounts for 45.2% of total variation. Spatial variation and spatial-structured environmental variation explain 11.8%, and 2.2%, respectively. Remained 40.8% of undetermined variation is attributed to biological and stochastic factors.

  7. Changes in forest biomass carbon stock in the Pearl River Delta between 1989 and 2003

    Institute of Scientific and Technical Information of China (English)

    YANG Kun; GUAN Dongsheng

    2008-01-01

    Forest ecosystems play a significant role in maintaining climate stability at the regional and global scales as an important carbon sink. Regional forest carbon storage and its dynamic changes in the Pearl River Delta have been estimated using the continuous biomass expansion factor (BEF) method based on field measurements of forests plots in different age classes and forest inventory data of three periods (1989-1993, 1994-1998, 1999-2003). The results show that regional carbon storage increased by 16.76%, from 48.57×106 to 56.71×106 tons, 80% of which was stored in forest stands. Carbon storage of other types of vegetation, with the exception of shrubland and woodland, increased. Carbon density of the regional forest increased by 14.31%, from 19.08 to 21.81 ton/hm2. Potential carbon storage of the regional forest may reach 39.96×107 tons when the forest biomass peaks with succession.

  8. Response of Soil Fungi Community Structure to Salt Vegetation Succession in the Yellow River Delta.

    Science.gov (United States)

    Wang, Yan-Yun; Guo, Du-Fa

    2016-10-01

    High-throughput sequencing technology was used to reveal the composition and distribution of fungal community structure in the Yellow River Delta under bare land and four kinds of halophyte vegetation (saline seepweed, Angiospermae, Imperata and Apocynum venetum [A. venetum]). The results showed that the soil quality continuously improved with the succession of salt vegetation types. The soil fungi richness of mild-salt communities (Imperata and A. venetum) was relatively higher, with Shannon index values of 5.21 and 5.84, respectively. The soil fungi richness of severe-salt-tolerant communities (saline seepweed, Angiospermae) was relatively lower, with Shannon index values of 4.64 and 4.66, respectively. The UniFrac metric values ranged from 0.48 to 0.67 when the vegetation was in different succession stages. A total of 60,174 valid sequences were obtained for the five vegetation types, and they were classified into Ascomycota, Basidiomycota, Chytridiomycota, Glomeromycota and Mucoromycotina. Ascomycota had the greatest advantage among plant communities of Imperata and A. venetum, as indicated by relative abundances of 2.69 and 69.97 %, respectively. Basidiomycota had the greatest advantage among mild-salt communities of saline seepweed and Angiospermae, with relative abundances of 9.43 and 6.64 %, respectively. Soil physical and chemical properties were correlated with the distribution of the fungi, and Mucor was significantly correlated with soil moisture (r = 0.985; P fungi were influenced by each other.

  9. [Major Air Pollutant Emissions of Coal-Fired Power Plant in Yangtze River Delta].

    Science.gov (United States)

    Ding, Qing-qing; Wei, Wei; Shen, Qun; Sun, Yu-han

    2015-07-01

    The emission factor method was used to estimate major air pollutant emissions of coal-fired power plant in the Yangtze River Delta (YRD) region of the year 2012. Results showed that emissions of SO2, NOx, dust, PM10, PM2.5 were respectively 473 238, 1 566 195, 587 713, 348 773 and 179 820 t. For SO2 and NOx, 300 MW and above class units made contributions of 85% and 82% in emission; while in the respect of dust, PM10 and PM2.5 contribution rates of 100 MW and below class units were respectively 81%, 53% and 40%. Considering the regional distribution, Jiangsu discharged the most, followed by Zhejiang, Shanghai. According to discharge data of several local power plants, we also calculated and made a comparative analysis of emission factors in different unit levels in Shanghai, which indicated a lower emission level. Assuming an equal level was reached in whole YRD, SO2 emission would cut down 55. 8% - 65. 3%; for NOx and dust emissions were 50. 5% - 64. 1% and 3. 4% - 11. 3%, respectively. If technologies and pollution control of lower class units were improved, the emission cuts would improve. However, according to the pollution realities of YRD, we suggested to make a multiple-cuts plan, which could effectively improve the reaional atmospheric environment.

  10. Saline-alkali land in the Yellow River Delta:amelioration zonation based on GIS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Soil salinization is one of the major land degradation types andhas greatly influenced sustainable agricultural development. Zonation of saline-alkali land is the precondition for effective amelioration. The present situation of saline-alkali land is monitored by remote sensing image processing. Causes for land salinization are analyzed, especially the two key factors, ground water depth and its mineralization degree, are analyzed by using long-term observation data. Previously,zonation of saline-alkali soil was made descriptively and artificially. Based on the present situation of saline-alkali land, ground water depth and ground water mineralization degree, the zonation of salinealkali land for amelioration in the Yellow River Delta was completed quantitatively. Four different ypes of saline-alkali land amelioration zones are delineated, namely, easy ameliorated zone,elatively difficult ameliorated zone, difficult ameliorated zone and unfavorable ameliorated zone.Countermeasures for ameliorating saline-alkali soils are put forward according to ecological conditions of different saline-alkali land zones.

  11. Ecological Effects of Roads on the Plant Diversity of Coastal Wetland in the Yellow River Delta

    Directory of Open Access Journals (Sweden)

    Yunzhao Li

    2014-01-01

    Full Text Available The 26 sample sites in 7 study plots adjacent to asphalt road and earth road in coastal wetland in the Yellow River Delta were selected to quantify plant diversity using quadrat sampling method in plant bloom phase of July and August 2012. The indice of βT and Jaccard’s coefficient were applied to evaluate the species diversity. The results showed that the plant diversities and alien plants were high in the range of 0–20 m to the road verge. There were more exotics and halophytes in plots of asphalt roadside than that of earth roadside. However, proportion of halophytes in habitats of asphalt roadsides was lower than that of earth roadside. By comparing β-diversity, there were more common species in the asphalt roadsides than that in the earth roadsides. The similarity of plant communities in studied plots of asphalt roadsides and earth roadsides increased with increasing the distance to road verge. The effect range of roads for plant diversity in study region was about 20 m to road verge. Our results indicate that the construction and maintenance of roads in wetland could increase the plant species diversities of communities and risk of alien species invasion.

  12. Particulate matter pollution research in the Yangtze River Delta: Observations, processes, modeling and health effects

    Science.gov (United States)

    Yu, Jian Zhen; Cao, Junji; Hu, Min; Kan, Haidong; Fu, Tzung-May

    2015-12-01

    The Yangtze River Delta (YRD) covers an area of 110,915 square km, including seven cities of northern Zhejiang Province, the Shanghai municipality and eight cities of southern Jiangsu Province. It is home to ∼110 million people and its GDP accounts for 17.4% of the whole China Economy (Hong Kong Trade Development Council Research, 2013). The YRD economy is greatly driven by heavy industries such as machinery, chemicals and automobile manufacturing. It is also a large producer of agricultural products, including wheat, rice, and corn. Its transport infrastructure is highly developed, with the number of vehicles per km2 higher than that in the developed countries. Two out of the ten top ports in China (Shanghai and Ningbo-Zhoushan ports) are located in the YRD. As a fast-developing and an important economic powerhouse of the Chinese Mainland, worsening of air quality and increasing pollution episodes in this region has led to heightened public health concerns and intensified research.

  13. [Modeling Study of A Typical Summer Ozone Pollution Event over Yangtze River Delta].

    Science.gov (United States)

    Zhang, Liang; Zhu, Bin; Gao, Jin-hui; Kang, Han-qing; Yang, Peng; Wang, Hong-lei; Li, Yue-e; Shao, Ping

    2015-11-01

    WRF/Chem model was used to analyze the temporal and spatial distribution characteristics and physical and chemical mechanism of a typical summer ozone pollution event over Yangtze River Delta (YRD). The result showed that the model was capable of reproducing the temporal and spatial distribution and evolution characteristics of the typical summer ozone pollution event over YRD. The YRD region was mainly affected by the subtropical high-pressure control, and the weather conditions of sunshine, high temperature and small wind were favorable for the formation of photochemical pollution on August 10-18, 2013. The results of simulation showed that the spatial and temporal distribution of O3 was obviously affected by the meteorological fields, geographic location, regional transport and chemical formation over YRD. The sensitivity experiment showed that the O3 concentration affected by maritime airstream was low in Shanghai, but the impact of Shanghai emissions on the spatial and temporal distribution of O3 concentration over YRD was significant; The main contribution of the high concentration of O3 in Nanjing surface was chemical generation ( alkene and aromatic) and the vertical transport from high-altitude O3, whereas the main contribution of the high concentration of O3 in Hangzhou and Suzhou was physics process. The influence of the 15:00 peak concentration of O3 over YRD was very obvious when O3 precursor was reduced at the maximum O3 formation rate (11-13 h).

  14. Formation of Equilibrium Beach Profile of the Abandoned Yellow River Delta Coast in North Jiangsu

    Institute of Scientific and Technical Information of China (English)

    徐敏; 陆培东; 雷智益

    2001-01-01

    The abandoned Yellow River Delta coast is a typical erodible silty and muddy coast in China. The paper analyses the marine dynamic characteristics and the mechanism of beach erosion of this area. Analysis and calculation show that in this sea area wave and tidal current action should be considered. Based on the above analysis, an equilibrium beach profile calculation model is developed, in which the wave-current interaction is considered while sediment supply and sediment re-deposition are neglected. The model consists of four parts: (1) calculation of wave parameters, (2) calculation of velocity due to wave-current interaction at different water depth, (3) calculation of friction velocity and shear stress at different water depths, and (4) calculation of the amount of sediment erosion, erosion intensity and variation of beach profile. Calculated results are in good agreement with observed data. Finally, the evolution tendency is discussed and the equilibrium beach profile of this coast is calculated. Based on prediction, the slope of equilibrium beach profile is about 1/85.

  15. Understanding Land Use and Land Cover Dynamics from 1976 to 2014 in Yellow River Delta

    Directory of Open Access Journals (Sweden)

    Baolei Zhang

    2017-03-01

    Full Text Available Long-term intensive land use/cover changes (LUCCs of the Yellow River Delta (YRD have been happening since the 1960s. The land use patterns of the LUCCs are crucial for bio-diversity conservation and/or sustainable development. This study quantified patterns of the LUCCs, explored the systematic transitions, and identified wetland change trajectory for the period 1976–2014 in the YRD. Landsat imageries of 1976, 1984, 1995, 2006, and 2014 were used to derive nine land use classes. Post classification change detection analysis based on enhanced transition matrix was applied to identify land use dynamics and trajectory of wetland change. The five cartographic outputs for changes in land use underlined major decreases in natural wetland areas and increases in artificial wetland and non-wetland, especially aquafarms, salt pans and construction lands. The systematic transitions in the YRD were wetland degradation, wetland artificialization, and urbanization. Wetland change trajectory results demonstrated that the main wetland changes were wetland degradation and wetland artificialization. Coastline change is the subordinate reason for natural wetland degradation in comparison with human activities. The results of this study allowed for an improvement in the understanding of the LUCC processes and enabled researchers and planners to focus on the most important signals of systematic landscape transitions while also allowing for a better understanding of the proximate causes of changes.

  16. SPATIAL AND SEASONAL DISTRIBUTIONS OF ATMOSPHERIC CARBONACEOUS AEROSOLS IN PEARL RIVER DELTA REGION, CHINA

    Institute of Scientific and Technical Information of China (English)

    Junji Cao; Shuncheng Lee; Kinfai Ho; Shichun Zou; Xiaoye Zhang; Jianguo Pan

    2003-01-01

    Concentrations and spatial distributions of organic carbon (OC) and elemental carbon (EC) in atmospheric particles were measured at 8 sites in four cities (Hong Kong, Guangzhou, Shenzhen and Zhuhai) of Pearl River Delta Region (PRDR), China during 2001 winter period and 2002 summer period. PM2.5 (particle diameter smaller than 2.5μm)and PM10 (particle diameter smaller than 10 μm) samples were collected on pre-fired quartz filters with mini-volume samplers and analyzed using thermal optical reflectance (TOR) method. The average PM2.5 and PM10 level were 60.1naceous aerosol accounted for 37.8% of the PM2.5 and 32.8% of the PM10. The highest concentrations of OC and EC were observed at Guangzhou city in both winter and summer seasons. The average OC/EC ratios were 2.4 for PM2.5and 2.5 for PM10, indicating the presence of secondary organic aerosols. The OC and EC in PRDR were found to be strongly correlated (correlation coefficients >0.6), which implied that similar emission source contribute to the ambient carbon particles.

  17. Emergy Synthesis and Regional Sustainability Assessment: Case Study of Pan-Pearl River Delta in China

    Directory of Open Access Journals (Sweden)

    Guomin Li

    2014-08-01

    Full Text Available In this paper, emergy analysis is used in association with the ternary diagrams and geographic information system (GIS tools to improve the evaluation of sustainability for the Pan-Pearl River Delta (PPRD region. Emergy accounting of PPRD is estimated, and various emergy-based indicators are reported. Ternary diagrams are drawn to provide a graphical representation of the emergy accounting data. Finally, the GIS tools are employed to assist in the emergy-based spatial analysis, and emergy density based on flat land area is mapped to reflect the intensity of emergy use in human activity areas. Results show the following: (1 the current development path of the PPRD region, with the value of emergy sustainability index (ESI = 0.227 significantly lower than one, is unsustainable in the long run; (2 Guangdong has the lowest ESI value (0.071, and the ESI values of Fujian, Guangxi, Hunan and Jiangxi are lower than 0.5, indicating that the economy in these provinces overly relies on non-renewable and imported resources; (3 Guizhou has a high emergy yield rate and is thus the main energy supplier in PPRD; and (4 among the nine provinces in PPRD, only Hainan has an ESI value (2.145 higher than one.

  18. Hair mercury levels and food consumption in residents from the Pearl River Delta: South China.

    Science.gov (United States)

    Shao, Dingding; Kang, Yuan; Cheng, Zhang; Wang, Hongsheng; Huang, Minjuan; Wu, Shengchun; Chen, Kunci; Wong, Ming H

    2013-01-15

    The Pearl River Delta (PRD) is located in the Southern part of China and is the main region for fish culture in Guangdong Province. In order to assess the potential health risks associated with dietary consumption of mercury, hair samples from 91 urban, town and fishing village residents, 37 species of fish, cereal, vegetables, and meat samples were collected. The average total mercury (THg) and methylmercury (MeHg) concentrations in hair were 1.08 ± 0.94 and 0.58 ± 0.59 μg/g, respectively. Daily Hg intake via fish consumption is significantly correlated with THg and MeHg accumulated in human hair (r=0.48, p<0.01; r=0.43, p<0.01). The estimated daily intake of Hg via different food types showed that both fish and cereal consumption were the two main routes of Hg exposure for residents in the sampling areas. Besides food intake, smoking was also an important source for daily THg intake in the smoke group, contributing 11-18% to EDI of THg.

  19. Total gaseous mercury in Pearl River Delta region, China during 2008 winter period

    Science.gov (United States)

    Li, Zheng; Xia, Chonghuan; Wang, Xinming; Xiang, Yunrong; Xie, Zhouqing

    2011-02-01

    Total gaseous mercury (TGM) was monitored at Wanqingsha, a rural site in the central Pearl River Delta region, south China from 23 November to 22 December, 2008. TGM ranged 0.50-18.67 ng m -3 with an average of 2.94 ng m -3. TGM was found to present a diurnal cycle with the maximum at 7:00-8:00 and the minimum at 14:00-16:00 (local time). The afternoon minimum in TGM were likely related to increased vertical mixing and the TGM oxidation by ozone, which was observed to negative correlation with TGM. A sudden increase in TGM from 6:00-7:00 could be due to activation of local surface emission sources by rising air temperature. Similar variations in TGM and trace gases including CO and SO 2 suggested potential anthropogenic sources contribution as well. Wind-rose patterns further indicated that the westerly wind might carry high concentration of TGM from the high mercury emission areas of Southwest China and/or local anthropogenic emission sources.

  20. Regional contribution to PM1 pollution during winter haze in Yangtze River Delta, China.

    Science.gov (United States)

    Tang, Lili; Yu, Hongxia; Ding, Aijun; Zhang, Yunjiang; Qin, Wei; Wang, Zhuang; Chen, Wentai; Hua, Yan; Yang, Xiaoxiao

    2016-01-15

    To quantify regional sources contributing to submicron particulate matter (PM1) pollution in haze episodes, on-line measurements combining two modeling methods, namely, positive matrix factorization (PMF) and backward Lagrangian particle dispersion modeling (LPDM), were conducted for the period of one month in urban Nanjing, a city located in the western part of Yangtze River Delta (YRD) region of China. Several multi-day haze episodes were observed in December 2013. Long-range transport of biomass burning from the southwestern YRD region largely contributed to PM1 pollution with more than 25% of total organics mass in a lasting heavy haze. The LPDM analysis indicates that regional transport is a main source contributing to secondary low-volatility production. The high-potential source regions of secondary low-volatility production are mainly located in areas to the northeast of the city. High aerosol pollution was mainly contributed by regional transport associated with northeastern air masses. Such regional transport on average accounts for 46% of total NR-PM1 with sulfate and aged low-volatility organics being the largest fractions (>65%).

  1. Winter soil respiration from different vegetation patches in the Yellow River Delta, China.

    Science.gov (United States)

    Han, Guangxuan; Yu, Junbao; Li, Huabing; Yang, Liqiong; Wang, Guangmei; Mao, Peili; Gao, Yongjun

    2012-07-01

    Vegetation type and density exhibited a considerable patchy distribution at very local scales in the Yellow River Delta, due to the spatial variation of soil salinity and water scarcity. We proposed that soil respiration is affected by the spatial variations in vegetation type and soil chemical properties and tested this hypothesis in three different vegetation patches (Phragmites australis, Suaeda heteroptera and bare soil) in winter (from November 2010 to April 2011). At diurnal scale, soil respiration all displayed single-peak curves and asymmetric patterns in the three vegetation patches; At seasonal scale, soil respiration all declined steadily until February, and then increased to a peak in next April. But, the magnitude of soil respiration showed significant differences among the three sites. Mean soil respiration rates in winter were 0.60, 0.45 and 0.17 μmol CO(2) m(-2) s(-1) for the Phragmites australis, Suaeda heteroptera and bare soil, respectively. The combined effect of soil temperature and soil moisture accounted for 58-68 % of the seasonal variation of winter soil respiration. The mean soil respiration revealed positive and linear correlations with total N, total N and SOC storages at 0-20 cm depth, and plant biomass among the three sites. We conclude that the patchy distribution of plant biomass and soil chemical properties (total C, total N and SOC) may affect decomposition rate of soil organic matter in winter, thereby leading to spatial variations in soil respiration.

  2. THE REGIONAL DEVELOPMENT IN THE PEARL RIVER DELTA IN NEW TERM

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Since China opening to outside world, the economy inthe Pearl(Zhujiang) River Delta(PRD) has been dou-ble digit growth. It has been known as one of mature fast growth areas in the world and become the model and hope of Chi-nese reform and opening to outside world. The regional development in PRD is the outcome of polarization effects. The polar-ization effects actually are extension of international regional division and a combination of Hongkong's influence and re-form and open-door policies on the mainland. Since the 1990s, driven by knowledge-based economy, the PRD has furtheradjusted the industrial structure and achieved good progress in upgrading industrial structure. Its high technology industryhas developed quickly and the economic internationalization has deepened, meanwhile, the region is going through transforma-tion and some new trends have begun to appear, which include: university towns springing up, industrial globalization andthe construction of Hi-tech development zones. The paper suggests that with the economic growth changing from relying onthe low level production elements to relying on high level production elements, the regional policies in GuangdongProvince should develop correspondingly: 1 ) make a plan to prohibite the blind construction in innovative spatial construc-tions; 2) make measures to attract the overseas talents to establish a pool of talent; 3) work out the favorable policies forabsorbing larger capital; 4) formulate the policy of attracting a cluster of industries to speed up the upgrade of industrialdevelopment.

  3. Arbuscular mycorrhizal status of wild plants in saline-alkaline soils of the Yellow River Delta.

    Science.gov (United States)

    Wang, Fa-Yuan; Liu, Run-Jin; Lin, Xian-Gui; Zhou, Jian-Min

    2004-04-01

    A survey was made of the arbuscular mycorrhizal (AM) status of five dominant wild plants Tamarix chinensis, Phragmites communis, Suaeda glauca, Aeluropus littoralis var. sinensis and Cirsium setosum in saline-alkaline soils of the Yellow River Delta that show low plant diversity. All of the species were colonized and showed typical AM structures (arbuscules, vesicles). The colonization percentage ranged from 0.2% to 9.5%, where C. setosum was the highest. The species richness of AMF at the different sites ranged from 2.00 to 2.40 per 50 ml soil, with an average of 2.16. Species diversity ranged from 1.99 to 2.22 per 50 ml soil, with an average of 2.13. Spore density ranged from 3 to 30 per 50 ml soil, with an average of 12. Glomus was the dominant genus, with a frequency and relative abundance of 88.1% and 68.4%, respectively. G. caledonium, with a frequency and relative abundance of 15.0% and 4.6%, respectively, was the dominant species. Differences were also observed in the distribution of AMF in different soil layers. Although there were still AM fungal spores in the layer 40 cm below the surface, most spores were found at a depth of 0-40 cm.

  4. Spatiotemporal Variations of Cloud Amount over the Yangtze River Delta, China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wenjing,ZHANG Ning,; SUN Jianning

    2014-01-01

    Based on the NOAA’s Advanced Very High Resolution Radiometer (AVHRR) Pathfi nder Atmospheres Extended (PATMOS-x) monthly mean cloud amount data, variations of annual and seasonal mean cloud amount over the Yangtze River Delta (YRD), China were examined for the period 1982-2006 by using a linear regression analysis. Both total and high-level cloud amounts peak in June and reach minimum in December, mid-level clouds have a peak during winter months and reach a minimum in summer, and low-level clouds vary weakly throughout the year with a weak maximum from August to October. For the annual mean cloud amount, a slightly decreasing tendency (-0.6% sky cover per decade) of total cloud amount is observed during the studying period, which is mainly due to the reduction of annual mean high-level cloud amount (-2.2% sky cover per decade). Mid-level clouds occur least (approximately 15% sky cover) and remain invariant, while the low-level cloud amount shows a signifi cant increase during spring (1.5% sky cover per decade) and summer (3.0%sky cover per decade). Further analysis has revealed that the increased low-level clouds during the summer season are mainly impacted by the local environment. For example, compared to the low-level cloud amounts over the adjacent rural areas (e.g., cropland, large water body, and mountain areas covered by forest), those over and around urban agglomerations rise more dramatically.

  5. Dynamics of soil organic and inorganic carbon in the cropland of upper Yellow River Delta, China

    Science.gov (United States)

    Guo, Yang; Wang, Xiujun; Li, Xianglan; Wang, Jiaping; Xu, Minggang; Li, Dongwei

    2016-10-01

    Soil inorganic carbon (SIC) and organic carbon (SOC) are important carbon reservoirs in terrestrial ecosystems. However, little attention was paid to SIC dynamics in cropland. We conducted a survey in the upper Yellow River Delta of North China Plain. We collected 155 soil samples from 31 profiles, and measured SOC, SIC and soluble Ca2+ and Mg2+ contents. Our results showed that mean SOC content decreased from 9.30 g kg-1 near the surface to 2.36 g kg-1 in 80-100 cm whereas mean SIC content increased from 10.48 to 12.72 g kg-1. On average, SOC and SIC stocks over 0-100 cm were 5.73 kg C m-2 and 16.89 kg C m-2, respectively. There was a significantly positive correlation (r = 0.88, P carbon cycle of China’s semi-arid region.

  6. Atrazine contamination in agricultural soils from the Yangtze River Delta of China and associated health risks.

    Science.gov (United States)

    Sun, J T; Pan, L L; Zhan, Yu; Tsang, Daniel C W; Zhu, L Z; Li, X D

    2017-04-01

    Atrazine is one of the most widely applied and persistent herbicides in the world. In view of limited information on the regional contamination of atrazine in soils in China, this study investigated the spatial distribution and environmental impacts of atrazine in agricultural soils collected from the Yangtze River Delta (YRD) as an illustrative analysis of rapidly developing regions in the country. The results showed that the concentrations of atrazine in the YRD agricultural soils ranged from atrazine in Zhejiang Province. The contamination of atrazine was closely associated with land use types. The concentrations and detection rates of atrazine were higher in corn fields and mulberry fields than in rice paddy fields. There was no significant difference in compositions of soil microbial phospholipids fatty acids among the areas with different atrazine levels. Positive relationship (R = 0.417, p atrazine and total microbial biomass. However, other factors, such as soil type and land management practice, might have stronger influences on soil microbial communities. Human health risks via exposure to atrazine in soils were estimated according to the methods recommended by the US EPA. Atrazine by itself in all the soil samples imposed very low carcinogenic risks (<10(-6)) and minimal non-cancer risks (hazard index <1) to adults and children.

  7. Gender relations and sexual communication among female students in the Mekong River Delta of Vietnam.

    Science.gov (United States)

    Bui, Thanh Cong; Diamond, Pamela M; Markham, Christine; Ross, Michael W; Nguyen-Le, Thanh-An; Tran, Ly Hai Thi

    2010-08-01

    Young women's ability to pursue a safer-sex life in line with their wishes is crucial to their sexual health. Although some previous observations have suggested that young women's lack of ability to negotiate safer sex is due to gender power imbalances in the culture of Vietnam, studies that have tested this hypothesis explicitly and quantitatively are few and far between. The present study aimed to test the association between perceived gender relations and perceived self-efficacy in communicating sexual matters among undergraduate female students in the Mekong River Delta of Vietnam. The analysis involved secondary data from 260 subjects from a larger survey regarding gender equity. Structural equation modeling was used to examine the study's hypothesis. Results showed that adherence to traditional gender roles and norms was significantly associated with female students' reduced self-efficacy to communicate on safer-sex matters, such as refusing unwanted sex or requesting condom use. This association remained invariant in the cross-validation process between partnered and unpartnered groups. Programmes that aim to promote safer-sex negotiation and practices for this population may need to address the influence of gender relations and power.

  8. Coastal hydrodynamics, geomorphology and sedimentary environments of two major Javanese river deltas. Program and preliminary results from the Snellius-II expedition (Indonesia)

    Science.gov (United States)

    Hoekstra, P.; Tiktanata

    River outflow, sediment transport, depositional processes and facies, as well as delta morphology of the rivers Solo and Porong (East Java, Indonesia) have been studied in detail during the Indonesian-Dutch Snellius II expedition (1984-1985). The humid tropical climate of Java in combination with the mountainous relief and the presence of easily erodible volcanic soils in relation to an intensive agriculture, results in a tremendous soil erosion and denudation rates are extremely high. Since river flow in the dry season is strongly reduced, sediment transport is mainly restricted to the wet season. Every wet season large volumes of sediment are carried towards the sea and the surplus of sediment in the coastal zone has resulted in the formation of two major river deltas. The Solo delta, a single-delta, is made up of one straight major channel with only few and small natural crevasses. Prominent natural levees are present; a consequence of the fact that in the wet season maximum outflow of the river coincides with high water. The development of this delta is considered to be a direct response to the high outflow velocities of the river, the huge mudload in the wet season and the low current and wave action. The Porong delta is a half-circular, lobate delta with a multidistributary network of channels which resulted in a regular distribution of sediment. A small part of the delivered sediments in both deltas escapes to sea and is seized by offshore, monsoon-induced coastal currents. The monsoon-type climate has a significant influence on depositional processes by determining river regime and sediment transport, by modifying river outflow and generating a coastal drift of water and suspended sediments.

  9. Residual Distribution and Risk Assessment of Polychlorinated Biphenyls in Surface Sediments of the Pearl River Delta, South China.

    Science.gov (United States)

    Lai, Zini; Li, Xiuli; Li, Haiyan; Zhao, Lina; Zeng, Yanyi; Wang, Chao; Gao, Yuan; Liu, Qianfu

    2015-07-01

    We analyzed residual PCBs in surface sediments at 19 sites in the Pearl River Delta in the wet and dry seasons. Seven indicative PCB congeners (PCB28, PCB52, PCB101, PCB118, PCB153, PCB138 and PCB180) were detected in the surface sediments, among which the detection rate and mass concentrations of PCB52 were the highest. Total concentrations of the seven PCBs ranged from 19.8 to 111 μg/kg, with an average of 48.2 μg/kg. For the spatial distribution, the sum of the seven PCB (∑PCB) concentrations for the stations that were located in the city region of the Pearl River Delta were significantly higher than the ∑PCB concentrations for the eight outlets of the Pearl River Delta (p < 0.05). According to the US National Oceanic and Atmospheric Administration ERL and ERM guideline concentrations, the PCB concentrations may occasionally lead to adverse effects, especially in the dry season.

  10. Quantification of Multiple Climate Change and Human Activity Impact Factors on Flood Regimes in the Pearl River Delta of China

    Directory of Open Access Journals (Sweden)

    Yihan Tang

    2016-01-01

    Full Text Available Coastal flood regimes have been irreversibly altered by both climate change and human activities. This paper aims to quantify the impacts of multiple factors on delta flood. The Pearl River Delta (PRD, with dense river network and population, is one of the most developed coastal areas in China. The recorded extreme water level (m.s.l. in flood season has been heavily interfered with by varied income flood flow, sea-level rise, and dredged riverbeds. A methodology, composed of a numerical model and the index R, has been developed to quantify the impacts of these driving factors in the the PRD. Results show that the flood level varied 4.29%–53.49% from the change of fluvial discharge, 3.35%–38.73% from riverbed dredging, and 0.12%–16.81% from sea-level rise. The variation of flood flow apparently takes the most effect and sea-level rise the least. In particular, dense river network intensifies the impact of income flood change and sea-level rise. Findings from this study help understand the causes of the the PRD flood regimes and provide theoretical support for flood protection in the delta region.

  11. Ice regime of the lower Peace River and ice-jam flooding of the Peace-Athabasca Delta

    Science.gov (United States)

    Beltaos, Spyros; Prowse, Terry D.; Carter, Tom

    2006-12-01

    The Peace-Athabasca Delta (PAD) in northern Alberta is one of the world's largest inland freshwater deltas, home to large populations of waterfowl, muskrat, beaver, and free-ranging wood bison. Beginning in the mid-1970s, a paucity of ice-jam flooding in the lower Peace River has resulted in prolonged dry periods and considerable reduction in the area covered by lakes and ponds that provide a habitat for aquatic life in the PAD region. Using archived hydrometric data and in situ observations, the ice regime of the lower Peace is described and quantified, setting the stage for identification of the conditions that lead to ice-jam flooding and replenishment of Delta habitat. The first such condition is the occurrence of a mechanical, as opposed to a thermal, breakup event; second, the river flow should be at least 4000 m3/s; and third, an ice jam should form within the last 50 km of the Peace River. The type of breakup event depends on the freeze-up stage and spring flow. The former has increased as a result of flow regulation, and the latter has decreased owing to changing climatic patterns. Both trends tend to inhibit the occurrence of mechanical breakups and contribute to less frequent ice-jam flooding. Potential mitigation strategies are discussed. Copyright

  12. Human induced discharge diversion in a tropical delta and its environmental implications: The Patía River, Colombia

    Science.gov (United States)

    Restrepo, Juan D.; Kettner, Albert

    2012-03-01

    SummaryThe Patía River, the number one in terms of sediment yield ˜1500 t km-2 yr-1 draining the western South America, has the most extensive and well developed delta on the Pacific coast, measuring 1700 km2. During the Holocene, nature forced the Patía delta to the south; however, a major water diversion, starting in 1972, diverted the Patía flow to the Sanguianga River, the latter, a small stream draining internal lakes from the Pacific lowlands. This human induced discharge diversion shifted the active delta plain back to the north and changed the northern estuarine system into an active delta plain. Overall, major environmental consequences of this discharge diversion in terms of morphological changes along the delta coast and distributary channels, are evidenced by: (1) coastal retreat along the abandoned delta lobe; 63% of the southern shoreline is retreating at maximum rates of 7 m yr-1, with a corresponding coastal land loss of 106 m yr-1; (2) transgressive barrier islands with exposed peat soils in the surf zone; (3) abandonment of former active distributaries in the southern delta plain with associated closing of inlets and formation of ebb tidal deltas; (4) breaching events on barrier islands; and (5) distributary channel accretion in the northern delta plain by morphological processes such as sedimentation (also in crevasses), overbank flow, increasing width of levees, interdistributary channel fill, and colonization of pioneer mangrove. The Sanguianga Mangrove National Park (SMNP), the largest mangrove reserve in Colombia, measuring 800 km2, lies in this former estuary, where major hydrologic and sedimentation changes are occurring. Observed environmental changes in the SMNP, include (1) seaward advance of the sub-aqueous delta front at the Sanquianga inlet evidenced by an increase in tidal flat area from 5.4 Mm2 in 1986 to 14 Mm2 in 2001; (2) freshening conditions in the Sanguianga distributary channel, a hydrologic change that has shifted the

  13. Extreme floods in the Mekong River Delta under climate change: combined impacts of upstream hydrological changes and sea level rise

    Science.gov (United States)

    Hoang, Long; Nguyen Viet, Dung; Kummu, Matti; Lauri, Hannu; Koponen, Jorma; van Vliet, Michelle T. H.; Supit, Iwan; Leemans, Rik; Kabat, Pavel; Ludwig, Fulco

    2016-04-01

    Extreme floods cause huge damages to human lives and infrastructure, and hamper socio-economic development in the Mekong River Delta in Vietnam. Induced by climate change, upstream hydrological changes and sea level rise are expected to further exacerbate future flood hazard and thereby posing critical challenges for securing safety and sustainability. This paper provides a probabilistic quantification of future flood hazard for the Mekong Delta, focusing on extreme events under climate change. We developed a model chain to simulate separate and combined impacts of two drivers, namely upstream hydrological changes and sea level rise on flood magnitude and frequency. Simulation results show that upstream changes and sea level rise substantially increase flood hazard throughout the whole Mekong Delta. Due to differences in their nature, two drivers show different features in their impacts on floods. Impacts of upstream changes are more dominant in floodplains in the upper delta, causing an increase of up to +0.80 m in flood depth. Sea level rise introduces flood hazard to currently safe areas in the middle and coastal delta zones. A 0.6 m rise in relative sea level causes an increase in flood depth between 0.10 and 0.70 m, depending on location by 2050s. Upstream hydrological changes and sea level rise tend to intensify each other's impacts on floods, resulting in stronger combined impacts than linearly summed impacts of each individual driver. Substantial increase of future flood hazard strongly requires better flood protection and more flood resilient development for the Mekong Delta. Findings from this study can be used as quantified physical boundary conditions to develop flood management strategies and strategic delta management plans.

  14. Assessment of Environmental Flows for the Rivers of Western Ganges Delta with Special Reference to Indian Sundarban

    Science.gov (United States)

    Bhadra, T.; Hazra, S.; Ghosh, S.; Barman, B. C.

    2016-12-01

    The Indian Sundarban, situated on the western tide-dominated part of the Ganges delta was formed by the sedimentation of the Ganges and its tributaries. Freshwater is a scarce resource in the Sundarban though it is traversed by rivers. Most of the rivers of Western Ganges Delta, which used to nourish the Sundarban, have become defunct with the passage of time. To ensure sustainable flow and to enhance the flow-dependent ecosystem services in this region, assessment of environmental flows within the system is required. A pilot assessment of environment flows, supported by IUCN has been carried out in some specific river reaches of Western Ganges Delta under the present study. The holistic Building Block Methodology (BBM) has been modified and used for the assessment of environmental flows. In the modified BBM, three distinctive blocks namely Hydro-Morphology, Ecology and Socio-Economy have been selected and indicators like Ganges Dolphin (Platanista gangetica), Sundari tree (Heritiera fomes) and Hilsa fish (Tenualosa ilisha) etc. have been determined to assess the environmental flows. As the discharge data of the selected rivers are restricted in the public domain, the SWAT model has been run to generate the discharge data of the classified rivers. The Hydraulic model, HEC-RAS has been calibrated in the selected River reaches to assess the habitat availability and its changes for indicator species under different flow condition. The study reveals that River Bhagirathi-Hugli requires 150-427 cumec additional water in monsoon and 850-1127 cumec additional water in post-monsoon months for Hilsa migration, whereas 327-486 cumec additional water in pre-monsoon and dry season and 227-386 cumec additional water in post-monsoon months are required for Dolphin movement. Flow requirement of river Ichhamati has also been estimated under the present study. The total required flow for the Sundarban ecosystem to reduce the salinity level from 30ppt to 14ppt during the dry and pre

  15. A Tale of Two Deltas: Contrasting Perspectives on the State of Natural and Human-modified Regions of the Ganges-Brahmaputra River Delta (Invited)

    Science.gov (United States)

    Goodbred, S. L.; Wallace Auerbach, L.; Wilson, C.; Gilligan, J. M.; Roy, K.; Ahmed, K.; Steckler, M. S.; Seeber, L.; Akhter, S. H.; Hossain, S.

    2013-12-01

    Effective risk analysis and the management of complex coastal systems require that the scale of interest be well defined. Here we present recent research from the Ganges-Brahmaputra river delta (GBD) that highlights different, if not divergent, perspectives on the current status of this system and its potential response to future environmental change. The contrasts emerge from viewing the GBD at different temporal and spatial scales, raising the question of how scientists, stakeholders, and decision makers might most effectively develop a shared understanding of large, at-risk delta systems. Among the world's deltas, the GBD is often cited as being highly vulnerable to future sea-level rise and environmental change, owing to its vast low-lying landscape and large human population. Taking a broad perspective, however, it is not coincident that the GBD, the world's largest delta system, is fed by immense water and sediment discharge from the Asian monsoon and Himalayan orogen - simply, the size of the GBD reflects the robust processes that have constructed and maintained it. At the regional scale, the deltaplain itself is interconnected by a labyrinth of fluvial and tidal channels that effectively convey sediment to most areas of the landscape, through overbank flooding, distributaries, and tidal transport. Together, the sediment supply, water discharge, and dense channel network bless the GBD with potential basinwide accretion rates >5 mm/yr. More locally, modern sedimentation rates >10 mm/yr are observed in many areas of the tidal delta plain, which are sufficient to maintain land-surface elevations under a variety of sea-level rise scenarios, or at least to mitigate whatever effects do occur. The long-term stratigraphic record of the GBD also reflects a system in dynamic equilibrium, with major landforms persisting through changes in sea level, sediment loading, river avulsion, and delta lobe switching - together providing an encouraging outlook in the face of

  16. Initiation of the Mekong River delta at 8 ka: evidence from the sedimentary succession in the Cambodian lowland

    Science.gov (United States)

    Tamura, Toru; Saito, Yoshiki; Sieng, Sotham; Ben, Bunnarin; Kong, Meng; Sim, Im; Choup, Sokuntheara; Akiba, Fumio

    2009-02-01

    Modern deltas are understood to have initiated around 7.5-9 ka in response to the deceleration of sea-level rise. This episode of delta initiation is closely related to the last deglacial meltwater events and eustatic sea-level rises. The initial stage of the Mekong River delta, one of the world's largest deltas, is well recorded in Cambodian lowland sediments. This paper integrates analyses of sedimentary facies, diatom assemblages, and radiocarbon dates for three drill cores from the lowland to demonstrate Holocene sedimentary evolution in relation to sea-level changes. The cores are characterized by a tripartite succession: (1) aggrading flood plain to natural levee and tidal-fluvial channel during the postglacial sea-level rise (10-8.4 ka); (2) aggrading to prograding tidal flats and mangrove forests around and after the maximum flooding of the sea (8.4-6.3 ka); and (3) a prograding fluvial system on the delta plain (6.3 ka to the present). The maximum flooding of the sea occurred at 8.0 ± 0.1 ka, 2000 years before the mid-Holocene sea-level highstand, and tidal flats penetrated up to 20-50 km southeast of Phnom Penh after a period of abrupt ˜5 m sea-level rise at 8.5-8.4 ka. The delta progradation then initiated as a result of the sea-level stillstand at around 8-7.5 ka. Another rapid sea-level rise at 7.5-7 ka allowed thick mangrove peat to be widely deposited in the Cambodian lowland, and the peat accumulation endured until 6.3 ka. Since 6.3 ka, a fluvial system has characterized the delta plain, and the fluvial sediment discharge has contributed to rapid delta progradation. The uppermost part of the sedimentary succession, composed of flood plain to natural-levee sediments, reveals a sudden increase in sediment accumulation over the past 600-1000 years. This increase might reflect an increase in the sediment yield due to human activities in the upper to middle reaches of the Mekong, as with other Asian rivers.

  17. Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2007 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Sobocinski, Kathryn; Johnson, Gary; Sather, Nichole [Pacific Northwest National Laboratory

    2008-03-17

    This document is the first annual report for the study titled 'Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta in the Lower Columbia River'. Hereafter, we refer to this research as the Tidal Freshwater Monitoring (TFM) Study. The study is part of the research, monitoring, and evaluation effort developed by the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS). The project is performed under the auspices of the Northwest Power and Conservation Council's Columbia Basin Fish and Wildlife Program. The goal of the 2007-2009 Tidal Freshwater Monitoring Study is to answer the following questions: In what types of habitats within the tidal freshwater area of the lower Columbia River and estuary (LCRE; Figure 1) are yearling and subyearling salmonids found, when are they present, and under what environmental conditions?1 And, what is the ecological importance2 of shallow (0-5 m) tidal freshwater habitats to the recovery of Upper Columbia River spring Chinook salmon and steelhead and Snake River fall Chinook salmon? Research in 2007 focused mainly on the first question, with fish stock identification data providing some indication of Chinook salmon presence at the variety of habitat types sampled. The objectives and sub-objectives for the 2007 study were as follows: (1) Habitat and Fish Community Characteristics-Provide basic data on habitat and fish community characteristics for yearling and subyearling salmonids at selected sites in the tidal freshwater reach in the vicinity of the Sandy River delta. (1a) Characterize vegetation assemblage percent cover, conventional water quality, substrate composition, and beach slope at each of six sampling sites in various tidal freshwater habitat types. (1b

  18. Impact of the Hoa Binh Dam (Vietnam on water and sediment budgets in the Red River basin and delta

    Directory of Open Access Journals (Sweden)

    D. V. Vu

    2014-01-01

    Full Text Available The Hoa Binh Dam, located on a tributary of the Red River in Vietnam, has a capacity of 9.45 × 109 m3 and was commissioned in December 1988. Although being important for flood prevention, electricity production, and irrigation in northern Vietnam, the Hoa Binh Dam has also highly influenced the suspended sediment distribution in the lower Red River basin, in the delta and in the coastal zone. Its impact was analysed from 50 yr dataset of water discharge and suspended sediment concentration (1960–2010 and the distribution of water and sediment across the nine mouths of the delta was calculated using the MIKE 11 numerical model before and after the dam settlement. Although water discharge at the delta inlet decreased by only 8.8%, the yearly suspended sediment flux dropped, on average from 119 to 43 × 106 t yr−1 at Son Tay near Hanoi, and from 85 to 35 × 106 t yr−1 in the river mouths. Water regulation has led to decreased water discharge in the wet season and increased water discharge in the dry season. Suspended sediment discharge proportionally increased in northern and southern estuaries and decreased through the main and central Ba Lat mouth. Tidal pumping, which causes a net sediment flux from the coast to the estuary at low discharge, is high in the northern delta, as a consequence of the high tidal range (up to 4.5 m in spring tide; diurnal tide. The shifts in the dynamic and characteristics of the turbidity maximum zone in the Cam-Bach Dang estuary are probably the cause of the enhanced sediment deposition in the Haiphong harbor. Along the coast, the reduced sedimentation rates are coincident with the lower sediment delivery that has been observed since the impoundment of the Hoa Binh Dam.

  19. Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2007

    Energy Technology Data Exchange (ETDEWEB)

    Sobocinski, Kathryn L.; Johnson, Gary E.; Sather, Nichole K.; Storch, Adam; Jones, Tucker A.; Mallette, Christine; Dawley, Earl M.; Skalski, John R.; Teel, David; Moran, Paul

    2008-03-18

    This document is the first annual report for the study titled “Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta in the Lower Columbia River.” Hereafter, we refer to this research as the Tidal Freshwater Monitoring (TFM) Study. The study is part of the research, monitoring, and evaluation effort developed by the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS). The project is performed under the auspices of the Northwest Power and Conservation Council’s Columbia Basin Fish and Wildlife Program.

  20. Severe petrol contamination in the aquifer of the Llobregat river delta. Grave contaminacion por gasolina en el acuifero del delta del rio Llobregat

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Gonzalez, E.

    1993-07-01

    On 16-09-91 an attack on an oil pipeline led to some 70 tons of petrol spilling out and catching fire. About 20 tons filtered down into the aquifer of the river Llobregat delta. On 08-12-91 the presence of petrol was detected in a well used for supplying water about 1 km downstream. A system was set up for monitoring and extracting the polluted ground water. The volume affected had now reached 3.5 hm''3. The decontamination costs came to 245 million pesetas in comparison to only 10 millions pesetas for the petrol spill. The cost of extracting the water was 70 pta/m''3. Finally the importance of regional planning and the need to prevent such accidents is pointed out. The means necessary to deal with them should be available. (Author)

  1. Regional and local new particle formation events observed in the Yangtze River Delta region, China

    Science.gov (United States)

    Dai, Liang; Wang, Honglei; Zhou, Luyu; An, Junlin; Tang, Lili; Lu, Chunsong; Yan, Wenlian; Liu, Ruiyang; Kong, Shaofei; Chen, Mindong; Lee, Shanhu; Yu, Huan

    2017-02-01

    To study the spatial inhomogeneity of new particle formation (NPF) in the polluted atmosphere of China, we conducted simultaneous measurements at an urban site near a petrochemical industrial area and a regional background site in the Yangtze River Delta region from September to November 2015. At the urban site we observed a type of local NPF event (number of events: n = 5), in which nucleation was limited to a small area but persisted for 6.8 h on average during the daytime. Formation rates of 5 nm particles (J5) were found to be correlated positively with the H2SO4 proxy (log J5 versus log[H2SO4] slope near 1) in both local and regional events. Furthermore, J5 was enhanced by the anthropogenic volatile organic carbon (VOC) plumes from nearby industrial area in the local events compared to the regional events. Size-dependent aerosol dynamics calculation showed that in comparison with the observed regional events, the local events were featured with high nucleation rate (J1.3 > 1000 cm-3 s-1), high growth rate of sub-3 nm particles (GRsub-3 > 20 nm h-1), and high number concentration of nucleation mode particles (mean peak N5-20: 6 × 104 cm-3). Considering these features, the local NPF events of anthropogenic origin may also be an important contributor to cloud condensation nuclei concentrations in urban and regional scales. In addition, the comparison of simultaneous regional NPF events between the two sites (number of events: n = 7) suggested that regional NPF intensity may be underestimated by the single-point measurement at an urban site, due to the heterogeneity of air masses.

  2. Source Apportionment of Volatile Organic Compounds in an Urban Environment at the Yangtze River Delta, China.

    Science.gov (United States)

    An, Junlin; Wang, Junxiu; Zhang, Yuxin; Zhu, Bin

    2017-04-01

    Volatile organic compounds (VOCs) were collected continuously during June-August 2013 and December 2013-February 2014 at an urban site in Nanjing in the Yangtze River Delta. The positive matrix factorization receptor model was used to analyse the sources of VOCs in different seasons. Eight and seven sources were identified in summer and winter, respectively. In summer and winter, the dominant sources of VOCs were vehicular emissions, liquefied petroleum gas/natural gas (LPG/NG) usage, solvent usage, biomass/biofuel burning, and industrial production. In summer, vehicular emissions made the most significant contribution to ambient VOCs (38%), followed by LPG/NG usage (20%), solvent usage (19%), biomass/biofuel burning (13%), and industrial production (10%). In winter, LPG/NG usage accounted for 36% of ambient VOCs, whereas vehicular emissions, biomass/biofuel burning, industrial production and solvent usage contributed 30, 18, 9, and 6%, respectively. The contribution of LPG/NG usage in winter was approximately four times that in summer, whereas the contribution from biomass/biofuel burning in winter was more than twice that in summer. The sources related to vehicular emissions and LPG/NG usages were important. Using conditional probability function analysis, the VOC sources were mainly associated with easterly, northeasterly and southeasterly directions, pointing towards the major expressway and industrial area. Using the propylene-equivalent method, paint and varnish (23%) was the highest source of VOCs in summer and biomass/biofuel burning (36%) in winter. Using the ozone formation potential method, the most important source was biomass/biofuel burning (32% in summer and 47% in winter). The result suggests that the biomass/biofuel burning and paint and varnish play important roles in controlling ozone chemical formation in Nanjing.

  3. Assessment of Spatial Distribution and Submerged Scope for Storm Surge in the Pearl River Delta Region

    Institute of Scientific and Technical Information of China (English)

    LI Kuo; LI Guo-sheng

    2011-01-01

    The aim of this study was to explore the spatial distribution and submerged scope for storm surge in the Pearl River Delta (PRD) region.Based on the data of storm surges in the PRD region in the past 30 years, the return periods of 12 tide-gauge stations for storm surges were calculated separately with the methods of Gumbel and Pearson-iii.The data of another six tide-gauge stations in Guangdong Coast was quoted to depict the overall features of storm surges in Guangdong.Using least-square method, the spatial distribution models of storm surges in different retum periods were established to reveal the distribution rule of the set-up values of storm surges.The spatial distribution curves of storm surges in different retum periods in the PRD Region were drawn up based on the models and the terrain of Guangdong Coast.According to the curves, the extreme set-up values of storm surges in 1 000,100, 10 a return periods were determined on each spot of Guangdong Coast.Applying the spatial analysis technology of ArcGIS, with the topography data of the PRD Region, the submerged scopes of flood caused by storm surge in 1 000, 100, 10 a return periods were drawn up.The loss caused by storm surges was estimated.Results showed that the storm surges and the topography of PRD region jointly led to the serious flood in the PRD region.This assessment would be useful for the planning and design department to make decision and provide government scientific basis for storm surge prediction, coastal engineering designing and the prevention of storm surge disaster.

  4. Assessment of organochlorine pesticide contamination in relation to soil properties in the Pearl River Delta, China.

    Science.gov (United States)

    Yu, Huan-Yun; Li, Fang-Bai; Yu, Wei-Min; Li, Yong-Tao; Yang, Guo-Yi; Zhou, Shun-Gui; Zhang, Tian-Bin; Gao, Yuan-Xue; Wan, Hong-Fu

    2013-03-01

    High levels of organochlorine pesticides (OCPs) such as hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) have been found in soil of the Pearl River Delta (PRD), attributable to high pesticide application in this area. Consequently, the occurrence and environmental effect of HCHs and DDTs in the PRD have attracted considerable attention. However, study focusing on the influence of potential factors such as soil property on the environmental fate of HCHs and DDTs in the PRD has been rare. The present study aimed to investigate the impact of soil physiochemical properties on the distribution patterns and fate of soil HCHs and DDTs on a large spatial scale. Levels of HCHs (sum of α-, β-, γ- and δ-HCH) and DDTs (sum of 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (p,p'-DDT), 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethane (p,p'-DDD), and 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethylene (p,p'-DDE)) in 151 soil samples covering all areas of the PRD and physiochemical parameters related to soil properties including pH, total organic carbon (TOC), total Fe (TFe), DCB-Fe (DFe), amorphous-Fe (AFe), complexed-Fe (CFe), total Mn (TMn), DCB-Mn (DMn), amorphous-Mn (AMn), complexed-Mn (CMn) and cation exchange capacity (CEC) were determined. The residual levels of HCHs and DDTs in soils of the present study, which are mainly controlled by soil TOC and CFe content and varying spatially with land use types, may potentially pose ecological risk to plants and animals. On the other hand, transformation of soil HCHs may be affected by pH and DDT transformation correlated significantly with AFe and CFe. Currently, soil has become an important secondary source of OCPs and the re-emission potential of OCPs in soil was mainly affected by soil OCP concentrations and land use types.

  5. Is Spatial Resolution Critical in Urbanization Velocity Analysis? Investigations in the Pearl River Delta

    Directory of Open Access Journals (Sweden)

    Chunzhu Wei

    2017-01-01

    Full Text Available Grid-based urbanization velocity analysis of remote sensing imagery is used to measure urban growth rates. However, it remains unclear how critical the spatial resolution of the imagery is to such grid-based approaches. This research therefore investigated how urbanization velocity estimates respond to different spatial resolutions, as determined by the grid sizes used. Landsat satellite images of the Pearl River Delta (PRD in China from the years 2000, 2005, 2010 and 2015 were hierarchically aggregated using different grid sizes. Statistical analyses of urbanization velocity derived using different spatial resolutions (or grid sizes were used to investigate the relationships between socio-economic indicators and the velocity of urbanization for 27 large cities in PRD. The results revealed that those cities with above-average urbanization velocities remain unaffected by the spatial resolution (or grid-size, and the relationships between urbanization velocities and socio-economic indicators are independent of spatial resolution (or grid sizes used. Moreover, empirical variogram models, the local variance model, and the geographical variance model all indicated that coarse resolution version (480 m of Landsat images based on aggregated pixel yielded more appropriate results than the original fine resolution version (30 m, when identifying the characteristics of spatial autocorrelation and spatial structure variability of urbanization patterns and processes. The results conclude that the most appropriate spatial resolution for investigations into urbanization velocities is not always the highest resolution. The resulting patterns of urbanization velocities at different spatial resolutions can be used as a basis for studying the spatial heterogeneity of other datasets with variable spatial resolutions, especially for evaluating the capability of a multi-resolution dataset in reflecting spatial structure and spatial autocorrelation features in an

  6. Observationally-constrained carbonaceous aerosol source estimates for the Pearl River Delta area of China

    Science.gov (United States)

    Li, N.; Fu, T.-M.; Cao, J. J.; Zheng, J. Y.; He, Q. Y.; Long, X.; Zhao, Z. Z.; Cao, N. Y.; Fu, J. S.; Lam, Y. F.

    2015-11-01

    We simulated elemental carbon (EC) and organic carbon (OC) aerosols over the Pearl River Delta (PRD) area of China and compared the results to seasonal surface measurements, with the aim of quantifying carbonaceous aerosol sources from a "top-down" perspective. Our regional model was driven by current-best estimates of PRD EC (39.5 Gg C yr-1) and OC (32.8 Gg C yr-1) emissions and included updated secondary organic aerosol formation pathways. The simulated annual mean EC and OC concentrations were 4.0 and 7.7 μg C m-3, respectively, lower than the observed annual mean EC and OC concentrations (4.5 and 13.1 μg C m-3, respectively). We used multiple regression to match the simulated EC against seasonal mean observations. The resulting top-down estimate for EC emission in the PRD area was 52.9 ± 8.0 Gg C yr-1. We estimated the OC emission in the PRD area to be 60.2 ± 10.3 Gg C yr-1, based on the top-down EC emission estimate and the primary OC / EC ratios derived from bottom-up statistics. Using these top-down emission estimates, the simulated average annual mean EC and OC concentrations were improved to 4.4 and 9.5 μg C m-3, respectively, closer to the observations. Secondary sources accounted for 42 % of annual mean surface OC in our top-down simulations, with biogenic VOCs being the most important precursors.

  7. [Influence of Burning Fireworks on Air Quality During the Spring Festival in the Pearl River Delta].

    Science.gov (United States)

    Zhao, Wei; Fan, Shao-jia; Xie, Wen-zhang; Sun, Jia-ren

    2015-12-01

    Based on data from the air quality monitoring stations in the Pearl River Delta during the 2015 Spring Festival, the regional air quality was investigated and the impact of burning fireworks on urban air quality was assessed. The results showed that: Zhaoqing was the worst polluted city in PM₁₀, PM₂.₅, SO₂ and CO in terms of concentrations in the region during the period, Huizhou was the worst polluted city in O₃ and Guangzhou was the most polluted city in NO₂ at the same time. Compared to the data of last year, the SO₂, NO₂, CO, PM₁₀ and PM₂.₅ concentrations had decreased significantly, but the O₃ concentration had increased during the Spring Festival. Burning fireworks during the Spring Festival were mainly concentrated in the suburbs. The concentrated discharge of fireworks made the SO₂, PM₁₀ and PM₂.₅ concentrations increased significantly in the New Year's Eve night, even multiplied, but had no significant effect on CO, O₃ and NO₂. The rapid decline in PM₂.₅/PM₁₀ proportion was caused by the discharge of fireworks, and the ratio of PM₂.₅/PM₁₀ reached the minimum when concentration of particles reached the peak. By assessing, the maximum contribution of hourly concentration from burning fireworks in each city was between 16 µg · m⁻³ and 65 µg · m⁻³ for PM₂.₅, between 28 µg · m⁻³ and 138 µg · m⁻³ for PM₁₀ and between 9 µg · m⁻³ and 43 µg · m⁻³ for SO₂.

  8. Aerosol optical properties and mixing state of black carbon in the Pearl River Delta, China

    Science.gov (United States)

    Tan, Haobo; Liu, Li; Fan, Shaojia; Li, Fei; Yin, Yan; Cai, Mingfu; Chan, P. W.

    2016-04-01

    Aerosols contribute the largest uncertainty to the total radiative forcing estimate, and black carbon (BC) that absorbs solar radiation plays an important role in the Earth's energy budget. This study analysed the aerosol optical properties from 22 February to 18 March 2014 at the China Meteorological Administration Atmospheric Watch Network (CAWNET) station in the Pearl River Delta (PRD), China. The representative values of dry-state particle scattering coefficient (σsp), hemispheric backscattering coefficient (σhbsp), absorption coefficient (σabsp), extinction coefficient (σep), hemispheric backscattering fraction (HBF), single scattering albedo (SSA), as well as scattering Ångström exponent (α) were presented. A comparison between a polluted day and a clean day shows that the aerosol optical properties depend on particle number size distribution, weather conditions and evolution of the mixing layer. To investigate the mixing state of BC at the surface, an optical closure study of HBF between measurements and calculations based on a modified Mie model was employed for dry particles. The result shows that the mixing state of BC might be between the external mixture and the core-shell mixture. The average retrieved ratio of the externally mixed BC to the total BC mass concentration (rext-BC) was 0.58 ± 0.12, and the diurnal pattern of rext-BC can be found. Furthermore, considering that non-light-absorbing particles measured by a Volatility-Tandem Differential Mobility Analyser (V-TDMA) exist independently with core-shell and homogenously internally mixed BC particles, the calculated optical properties were just slightly different from those based on the assumption that BC exist in each particle. This would help understand the influence of the BC mixing state on aerosol optical properties and radiation budget in the PRD.

  9. Sources of excess urban carbonaceous aerosol in the Pearl River Delta Region, China

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, M.; Wang, F.; Hagler, G.S.W.; Hou, X.M.; Bergin, M.; Cheng, Y.A.; Salmon, L.G.; Schauer, J.J.; Louie, P.K.K.; Zeng, L.M.; Zhang, Y.H. [Peking University, Beijing (China). College of Environmental Science & Engineering

    2011-02-15

    Carbonaceous aerosol is one of the important constituents of fine particulate matter (PM2.5) in southern China, including the Pearl River Delta (PRD) region and Hong Kong (HK). During the study period (October and December of 2002, and March and June of 2003), the monthly average organic carbon (OC) ranged from 3.52 to 7.87 {mu} g m{sup -3} in Hong Kong and 4.14-20.19 {mu} g m{sup -3} in the PRD from simultaneous measurements at three sites in HK and four sites in the PRO. Compared to the PRD, the spatial distribution of carbonaceous aerosol in Hong Kong was relatively homogeneous. Sources contributing to excess OC in the PRO were examined, which is the difference between OC concentrations measured at the PRD sites to the average level in Hong Kong. Eight primary sources contributing to excess OC were identified with chemical mass balance modeling in a combination with molecular markers analyzed by gas chromatography/mass spectrometry. Excess OC at Guangzhou, the capital city of Guangdong province, was consistently high, ranging from 9.77 to 13.6 {mu} g m{sup -3}. Four primary sources including gasoline engine exhaust, diesel engine exhaust, biomass burning, and coal combustion accounted for more than 50% of excess OC in the PRD, especially in December (up to 76%). Mobile source emissions alone can contribute about 30% of excess OC. The unexplained or other excess OC was the highest at the rural site, but in general less than 20% at other sites. The coal combustion source contribution was unique in that it exhibited relatively homogeneous spatial distribution, indicating it was still an important source of carbonaceous aerosol in the PRD (17% of excess OC) during the study period.

  10. Arsenic contamination in the freshwater fish ponds of Pearl River Delta: bioaccumulation and health risk assessment.

    Science.gov (United States)

    Cheng, Zhang; Chen, Kun-Ci; Li, Kai-Bin; Nie, Xiang-Ping; Wu, Sheng Chun; Wong, Chris Kong-Chu; Wong, Ming-Hung

    2013-07-01

    This study investigated the extent of arsenic (As) contamination in five common species of freshwater fish (northern snakehead [Channa argus], mandrarin fish [Siniperca chuatsi], largemouth bass [Lepomis macrochirous], bighead carp [Aristichthys nobilis] and grass carp [Ctenopharyngodon idellus]) and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The total As concentrations detected in fish muscle and sediment in freshwater ponds around the PRD were 0.05-3.01 mg kg(-1) wet weight (w. wt) and 8.41-22.76 mg kg(-1) dry weight (d. wt), respectively. In addition, the As content was positively correlated (p < 0.05) to total organic carbon (TOC) contents in sediments. Biota sediment accumulation factor (BSAF) showed that omnivorous fish and zooplankton accumulated higher concentrations of heavy metals from the sediment than carnivorous fish. In addition, feeding habits of fish also influence As accumulation in different fish species. In this study, two typical food chains of the aquaculture ponds were selected for investigation: (1) omnivorous food chain (zooplankton, grass carp and bighead carp) and (2) predatory food chain (zooplankton, mud carp and mandarin fish). Significant linear relationships were obtained between log As and δ (15)N. The slope of the regression (-0.066 and -0.078) of the log transformed As concentrations and δ (15)N values, as biomagnifications power, indicated there was no magnification or diminution of As from lower trophic levels (zooplankton) to fish in the aquaculture ponds. Consumption of largemouth bass, northern snakehead and bighead carp might impose health risks of Hong Kong residents consuming these fish to the local population, due to the fact that its cancer risk (CR) value exceeded the upper limit of the acceptable risk levels (10(-4)) stipulated by the USEPA.

  11. Process analysis of regional aerosol pollution during spring in the Pearl River Delta region, China

    Science.gov (United States)

    Fan, Qi; Lan, Jing; Liu, Yiming; Wang, Xuemei; Chan, Pakwai; Hong, Yingying; Feng, Yerong; Liu, Yexin; Zeng, Yanjun; Liang, Guixiong

    2015-12-01

    A numerical simulation analysis was performed for three air pollution episodes in the Pearl River Delta (PRD) region during March 2012 using the third-generation air quality modeling system Models-3/CMAQ. The results demonstrated that particulate matter was the primary pollutant for all three pollution episodes and was accompanied by relatively low visibility in the first two episodes. Weather maps indicate that the first two episodes occurred under the influence of warm, wet southerly air flow systems that led to high humidity throughout the region. The liquid phase reaction of gaseous pollutants resulted in the generation of fine secondary particles, which were identified as the primary source of pollution in the first two episodes. The third pollution episode occurred during a warming period following a cold front. Relative humidity was lower during this episode, and coarse particles were the major pollution contributor. Results of process analysis indicated that emissions sources, horizontal transport and vertical transport were the primary factors affecting pollutant concentrations within the near-surface layer during all three episodes, while aerosol processes, cloud processes, horizontal transport and vertical transport had greater influence at approximately 900 m above ground. Cloud processes had a greater impact during the first two pollution episodes because of the higher relative humidity. In addition, by comparing pollution processes from different cities (Guangzhou and Zhongshan), the study revealed that the first two pollution episodes were the result of local emissions within the PRD region and transport between surrounding cities, while the third episode exhibited prominent regional pollution characteristics and was the result of regional pollutant transport.

  12. Black carbon measurements in the Pearl River Delta region of China

    Science.gov (United States)

    Huang, X.; Gao, R.; Schwarz, J. P.; Ling-Yan, H.; Fahey, D. W.; Laurel A, W.; Zeng, L.

    2009-12-01

    The Pearl River Delta (PRD) region in southeastern China is one of the most polluted industrial/metropolitan areas in the world. The 3C-STAR campaign (Synthesized Prevention Techniques for Air Pollution Complex and Integrated Demonstration in Key City-Cluster Region), carried out in October-November, 2008, was aimed at improving the understanding and quantification of air pollution in the region, while developing technical capacity for regional air quality monitoring and modeling. We report single-particle soot photometer (SP2) measurements and analyses of refractory black carbon (rBC) at Kaiping, a rural site downwind of the major pollution sources in the PRD area. The rBC mass loadings varied between 0.5 and 10 µg-rBC kg-air-1, and averaged 2.8 µg-rBC kg-air-1. These values are roughly an order of magnitude higher than those measured in the Houston, Texas, a major US metropolitan area. The rBC mass distributions show a primary lognormal peak with a median mass diameter of 0.22 µm volume-equivalent diameter (VED), which is similar to those observed in Houston and other regions with the SP2 instrument. A second mode with a mass median diameter of 0.69 µm VED, has not been observed before. Coatings are found on over 50% of rBC particles, suggesting that they are aged and/or of biomass-burning origin. The high rBC loadings cause significant heating of the atmosphere due to direct solar absorption. A diurnal heating rate of over 0.5 K day-1. is estimated for the average of entire dataset with a maximum heating rate near 3 K day-1.

  13. Inorganic aerosols responses to emission changes in Yangtze River Delta, China.

    Science.gov (United States)

    Dong, Xinyi; Li, Juan; Fu, Joshua S; Gao, Yang; Huang, Kan; Zhuang, Guoshun

    2014-05-15

    The new Chinese National Ambient Air Quality standards (CH-NAAQS) published on Feb. 29th, 2012 listed PM2.5 as criteria pollutant for the very first time. In order to probe into PM2.5 pollution over Yangtze River Delta, the integrated MM5/CMAQ modeling system is applied for a full year simulation to examine the PM2.5 concentration and seasonality, and also the inorganic aerosols responses to precursor emission changes. Total PM2.5 concentration over YRD was found to have strong seasonal variation with higher values in winter months (up to 89.9 μg/m(3) in January) and lower values in summer months (down to 28.8 μg/m(3) in July). Inorganic aerosols were found to have substantial contribution to PM2.5 over YRD, ranging from 37.1% in November to 52.8% in May. Nocturnal production of nitrate (NO3(-)) through heterogeneous hydrolysis of N2O5 was found significantly contribute to high NO3(-) concentration throughout the year. In winter, NO3(-) was found to increase under nitrogen oxides (NOx) emission reduction due to higher production of N2O5 from the excessive ozone (O3) introduced by attenuated titration, which further lead to increase of ammonium (NH4(+)) and sulfate (SO4(2-)), while other seasons showed decrease response of NO3(-). Sensitivity responses of NO3(-) under anthropogenic VOC emission reduction was examined and demonstrated that in urban areas over YRD, NO3(-) formation was actually more sensitive to VOC than NOx due to the O3-involved nighttime chemistry of N2O5, while a reduction of NOx emission may have counter-intuitive effect by increasing concentrations of inorganic aerosols.

  14. Contamination of PAHs in Sludge Samples from the Yangtze River Delta Area

    Institute of Scientific and Technical Information of China (English)

    SHEN Rong-Yan; LUO Yong-Ming; ZHANG Gang-Ya; TENG Ying; LI Zhen-Gao; WU Long-Hua

    2007-01-01

    To ascertain the contaminated conditions of polycyclic aromatic hydrocarbons (PAHs) in sludge and to evaluate the risk of application of this sludge for agricultural purposes, 44 sludge samples obtained from 15 cities in the Yangtze River Delta area of China were investigated using capillary gas chromatography/mass spectrometry (GC/MS) after ultrasonic extraction and silica gel cleanup. PAHs' contents ranged from 0.0167 to 15.4860 mg kg-1 (dry weight, DW) and averaged 1.376 mg kg-1, with most samples containing<1.5 mg kg-1. Pyrene (PY), fluoranthene (FL), benzo[b]fluoranthene (BbF), indeno[1,2,3-cd]pyrene (IND), benzo[a]pyrene (B[a]P), and benzo[g,h,i]perylene (BghiP) were the most dominant compounds, ranging from 0.1582 to 0.2518 mg kg-1. Single PAH, such as naphthalene (NAP, 2-benzene rings), phenan-threne (PA, 3-benzene rings), PY (4-benzene rings), and FL (3-benzene rings), had high detection rates (76.1%-93.5%). The distribution patterns of PAHs were found to vary with the sludge samples; however, the patterns showed that a few compounds with 2- and 3-benzene rings were commonly found in the samples, whereas those with 4-, 5-, and 6-benzene rings were usually less commonly found. All the 44 sludge samples were within the B[a]P concentration limit for sludge applied to agricultural land in China (< 3.0 mg kg-1). The probable sources of PAH contamination in the sludge samples were petroleum, petroleum products, and combustion of liquid and solid fuel. The concentrations and distributions of the 16 PAHs in sludge were related to sludge type, source, and treatment technology, together with the physicochemical properties.

  15. The Stability of Fine-grained Sediments from the Fraser River Delta

    Science.gov (United States)

    Amos, C. L.; Feeney, T.; Sutherland, T. F.; Luternauer, J. L.

    1997-10-01

    The stability and erodibility of benthic fine-grained sediments on the foreshore and upper foreslope of the Fraser River delta were measured using the in situbenthic flume—Sea Carousel. The erosion threshold [τ c(0)], which varied between 0·11 and 0·50 Pa, was inversely related to erosion rate. It was also proportional to sediment wet bulk density (ρ b) in the form: τ c(0)=7×10 -4 ρ b-0·47. This trend agreed with those obtained from four other sites across Canada that encompassed a wide range in sediment densities: 1000Academic Press Limited Three erosion types were observed: Type IA erosion was a surface phenomenon caused by the presence of a thin organic ' fluff ' layer. It occurred at current speeds less than 0·3 m s -1. Type 1B erosion (asymptotically decaying with time) characterized the mid-portions of each erosion time series, and occurred at current speeds of 0·3-0·9 m s -1. Type I/II erosion (transitional) was largely found on the foreslope, and occurred at current speeds in excess of 0·8 m s -1. The erosion process began in all cases under turbulent transitional flows. The change from Type I to Type II erosion corresponded to the onset of turbulent rough flows (60result of entrainment of small aggregates and flocs, whereas Type II erosion was the result of enlargement of surface irregularities, and subsequent undercutting and release of large aggregates. Mean erosion rate ( Em) was independent of either azimuthal current speed or bed shear stress. It was largely constant throughout each deployment and varied between 1·4 and 7·4×10 -4 kg m -2 s -1.

  16. Landscape ecological security assessment based on projection pursuit in Pearl River Delta.

    Science.gov (United States)

    Gao, Yang; Wu, Zhifeng; Lou, Quansheng; Huang, Huamei; Cheng, Jiong; Chen, Zhangli

    2012-04-01

    Regional landscape ecological security is an important issue for ecological security, and has a great influence on national security and social sustainable development. The Pearl River Delta (PRD) in southern China has experienced rapid economic development and intensive human activities in recent years. This study, based on landscape analysis, provides a method to discover the alteration of character among different landscape types and to understand the landscape ecological security status. Based on remotely sensed products of the Landsat 5 TM images in 1990 and the Landsat 7 ETM+ images in 2005, landscape classification maps of nine cities in the PRD were compiled by implementing Remote Sensing and Geographic Information System technology. Several indices, including aggregation, crush index, landscape shape index, Shannon's diversity index, landscape fragile index, and landscape security adjacent index, were applied to analyze spatial-temporal characteristics of landscape patterns in the PRD. A landscape ecological security index based on these outcomes was calculated by projection pursuit using genetic algorithm. The landscape ecological security of nine cities in the PRD was thus evaluated. The main results of this research are listed as follows: (1) from 1990 to 2005, the aggregation index, crush index, landscape shape index, and Shannon's diversity index of nine cities changed little in the PRD, while the landscape fragile index and landscape security adjacent index changed obviously. The landscape fragile index of nine cities showed a decreasing trend; however, the landscape security adjacent index has been increasing; (2) from 1990 to 2005, landscape ecology of the cities of Zhuhai and Huizhou maintained a good security situation. However, there was a relatively low value of ecological security in the cities of Dongguan and Foshan. Except for Foshan and Guangzhou, whose landscape ecological security situation were slightly improved, the cities had reduced

  17. Residues of fluoroquinolones in marine aquaculture environment of the Pearl River Delta, South China.

    Science.gov (United States)

    He, Xiuting; Wang, Zhaohui; Nie, Xiangping; Yang, Yufen; Pan, Debo; Leung, Anna O W; Cheng, Zhang; Yang, Yongtao; Li, Kaibin; Chen, Kunci

    2012-06-01

    Concentrations and distributions of selected fluoroquinolones (norfloxacin, ciprofloxacin and enrofloxacin) in water, sediments and nine kinds of fish species collected from 6 sites in two marine aquaculture regions of the Pearl River Delta, China, were analyzed by using high-performance liquid chromatography with fluorescence detector (HPLC). The results showed that the concentrations of ciprofloxacin and enrofloxacin were below the limits of quantification (LOQ) in all water samples except for norfloxacin. Norfloxacin and ciprofloxacin concentrations ranged from 1.88 to 11.20 ng g(-1) dry wt, 0.76-2.42 ng g(-1) dry wt in sediments collected from the Dapeng'ao region (sites 1-3) and ranged from 2.31 to 4.75 ng g(-1) dry wt, 1.26-1.76 ng g(-1) dry wt in sediments collected from the Hailing Island region (sites 4-6), respectively. However, no enrofloxacin was found in all sediment samples. The three fluoroquinolones (FQs) were detected in all fish samples, and the concentrations were higher in liver tissues than those in muscle tissues. The levels of norfloxacin were higher than ciprofloxacin and enrofloxacin in both liver and muscle tissues. Among the nine marine fish species, Siganus fuscescens from Hailing Island had a significantly high level of norfloxacin in liver tissue (254.58 ng g(-1) wet wt), followed by Sparus macrocephalus (133.15 ng g(-1) wet wt) from Dapeng'ao, and the lowest value was Lutianus argentimaculatus (5.18 ng g(-1) wet wt) from Hailing Island. The obtained results of FQs in present study do not represent a risk to the human health in Guangdong coastal area, based on the maximum residue limits (MRLs) established by Chinese Government and the acceptable daily intake (ADI) recommended by the Food and Agriculture Organization and World Health Organization (FAO/WHO).

  18. Soil sail content estimation in the yellow river delta with satellite hyperspectral data

    Science.gov (United States)

    Weng, Yongling; Gong, Peng; Zhu, Zhi-Liang

    2008-01-01

    Soil salinization is one of the most common land degradation processes and is a severe environmental hazard. The primary objective of this study is to investigate the potential of predicting salt content in soils with hyperspectral data acquired with EO-1 Hyperion. Both partial least-squares regression (PLSR) and conventional multiple linear regression (MLR), such as stepwise regression (SWR), were tested as the prediction model. PLSR is commonly used to overcome the problem caused by high-dimensional and correlated predictors. Chemical analysis of 95 samples collected from the top layer of soils in the Yellow River delta area shows that salt content was high on average, and the dominant chemicals in the saline soil were NaCl and MgCl2. Multivariate models were established between soil contents and hyperspectral data. Our results indicate that the PLSR technique with laboratory spectral data has a strong prediction capacity. Spectral bands at 1487-1527, 1971-1991, 2032-2092, and 2163-2355 nm possessed large absolute values of regression coefficients, with the largest coefficient at 2203 nm. We obtained a root mean squared error (RMSE) for calibration (with 61 samples) of RMSEC = 0.753 (R2 = 0.893) and a root mean squared error for validation (with 30 samples) of RMSEV = 0.574. The prediction model was applied on a pixel-by-pixel basis to a Hyperion reflectance image to yield a quantitative surface distribution map of soil salt content. The result was validated successfully from 38 sampling points. We obtained an RMSE estimate of 1.037 (R2 = 0.784) for the soil salt content map derived by the PLSR model. The salinity map derived from the SWR model shows that the predicted value is higher than the true value. These results demonstrate that the PLSR method is a more suitable technique than stepwise regression for quantitative estimation of soil salt content in a large area. ?? 2008 CASI.

  19. Mercury speciation and emission from municipal solid waste incinerators in the Pearl River Delta, South China.

    Science.gov (United States)

    Chen, Laiguo; Liu, Ming; Fan, Ruifang; Ma, Shexia; Xu, Zhencheng; Ren, Mingzhong; He, Qiusheng

    2013-03-01

    The potential for Hg release during municipal solid waste incineration (MSWI) is attracting increased attention due to high volume of municipal waste being treated by incineration in China. Emission amounts have been estimated using emission factors developed for other countries. To fine tune our emission estimate total mercury (THg) and mercury speciation were measured using isokinetic sampling in eight plants, of which six used grate furnace combustor (GFC) and two circulation fluidized bed combustors (CFBCs). Results showed that average THg concentration (19.5 ± 13.6 μg/Nm) in flue gas at the facilities that used CFBC was significantly lower than that at those using GFC (51.4 ± 28.3 μg/Nm, p=0.002). Gaseous oxidized mercury (GOM), gaseous elemental mercury (GEM, Hg), and particulate mercury (Hg) represented 95.5 ± 3.8%, 4.1 ± 3.9% and 0.4 ± 0.3% in GFC, and 63.8 ± 8.6%, 33.6 ± 10.5% and 2.6 ± 1.9% in CFBC, respectively. The measured average THg emission factor for the 8 MSWI plants was 208 ± 130 mg/t in the Pearl River Delta (PRD) region, with 217 ± 158 mg/t and 188 ± 17.7 mg/t were from GFC and CFBC, respectively. Using the average emission factor the estimated total mercury emissions from MSWI were 4.67 ± 2.91 t in China, and 770 ± 65.5 kg in the PRD region in 2010. Of these, 4240 ± 210 kg, 408 ± 231 kg and 14.8 ± 14.1 kg, and 688 ± 37 kg, 78.9 ± 40.6 kg and 3.2 ± 3.0 kg were GOM, Hg, and Hg, respectively. Mercury emissions will continue to increase as the amounts of MSW being incinerated increases.

  20. Importance of NOx control for peak ozone reduction in the Pearl River Delta region

    Science.gov (United States)

    Li, Ying; Lau, Alexis K. H.; Fung, Jimmy C. H.; Zheng, Junyu; Liu, Shawchen

    2013-08-01

    As major air pollutants and key precursors of several secondary air pollutants, nitrogen oxide (NOx) emissions are regulated in many countries. However, NOx control increases ozone concentrations when the ozone formation regime is volatile organic compound (VOC) limited. Although many studies have shown that NOx regulation reduces ozone levels over the long term, it is still of concern that NOx regulation increases short-term ozone levels in metropolitan regions, where ozone formation is found to be predominantly VOC-limited. The Pearl River Delta (PRD) in China is such a region. Our modeling sensitivity study shows that while NOx reduction in the PRD region may raise the mean ozone concentration, it can also decrease peak ozone levels. Similar changes are observed in the NOx and ozone data of the PRD regional air quality monitoring network (2006-2012), lending further credence to our results. In the model, this NOx control effect is a result of the complicated spatial and diurnal variations of the ozone formation regime. In most of the PRD region, the formation regime is VOC-limited in the morning and becomes NOx-limited during peak ozone hours. Although some areas are always VOC-limited, their ozone concentrations are relatively low, and the ozone increases caused by NOx reduction generally do not cause higher ozone levels than the region's original ozone maxima. Several control scenarios are simulated to evaluate the effects of various possible control regulations. Our results show that in addition to VOC control, NOx control can be effective for reducing peak ozone concentrations in the PRD region.

  1. Seasonal variations of anhydrosugars in PM2.5 in the Pearl River Delta Region, China

    Directory of Open Access Journals (Sweden)

    Kin Fai Ho

    2014-06-01

    Full Text Available Anhydrosugars including levoglucosan and mannosan are the most effective organic tracers for biomass burning aerosol in the atmosphere. In this study, to investigate the contribution of biomass burning emissions to the aerosol burden in the Pearl River Delta (PRD region, China, 24-hour integrated PM2.5 samples were collected simultaneously at four locations, (i Guangzhou (GZ, (ii Zhaoqing (ZQ in Guangdong province, (iii Hok Tsui (HT and (iv Hong Kong Polytechnic University (PU in Hong Kong, in four seasons between 2006 and 2007. Levoglucosan and mannosan, together with water-soluble inorganic ions and water-soluble organic carbon (WSOC, were determined to elucidate the seasonal and spatial variations in biomass burning contributions. The concentrations of levoglucosan and mannosan were on average 82.4±123 and 5.8±8.6 ng m−3, respectively. The WSOC concentrations ranged from 0.2 to 9.4 µg m−3, with an average of 2.1±1.6 µg m−3. The relative contributions of biomass burning emissions to OC were 33% in QZ, 12% in GZ, 4% at PU and 5% at HT, respectively, estimated by the measured levoglucosan to organic carbon ratio (LG/OC relative to literature-derived LG/OC values. The contributions from biomass burning emissions were in general 1.7–2.8 times higher in winter than those in other seasons. Further, it was inferred from diagnostic tracer ratios that a significant fraction of biomass burning emissions was derived from burning of hard wood and likely also from field burning of agricultural residues, such as rice straw, in the PRD region. Our results highlight the contributions from biomass/biofuel burning activities on the regional aerosol budget in South China.

  2. Science-policy interplay: Air quality management in the Pearl River Delta region and Hong Kong

    Science.gov (United States)

    Zhong, Liuju; Louie, Peter K. K.; Zheng, Junyu; Yuan, Zibing; Yue, Dingli; Ho, Josephine W. K.; Lau, Alexis K. H.

    2013-09-01

    The information provided by the scientific studies and control measures implemented in the Pearl River Delta (PRD) region of China reveals that tremendous progress has been made in the understanding of regional air pollution issues and the deployment of mitigation measures for alleviating these problems. Given the unparalleled rapid economic growth in the PRD over the past two decades, such progress was only made possible by strong, science-based support and the partnerships between government and research institutions in the region and overseas. Researchers from these partnership programs and related studies have deployed cutting-edge expertise and experience in various crucial mainland China and mainland China/Hong Kong-level projects. China recognizes the importance of protecting the environment and cleaning up the air in the pursuit of sustainable growth and economic development. To avoid falling into a cycle of event-driven clean-up efforts, China has recently taken a major step and updated the national ambient air quality standards. Clearly, China is implementing an increasing number of evidence-based policies to address air pollution problems. Thus, to bring a fresh impetus at a national level, the PRD must maintain and augment the Hong Kong-mainland collaborative momentum, inducing a "whole-China" effort to clean up air pollution. To strengthen the science-based support system and ensure continuous and concerted effort in implementing the regional multi-pollutant control strategy, there must be an overarching and integral Hong Kong-Guangdong science consortium framework supporting the formulation of regional policy and control measures built on common goals under the "one country, two systems" principle. The "PRD Approach" of the air quality management regime reflected regional cooperative efforts in synchronous air pollutant control, catalyzed the crucial role of information disclosure and subtly transformed the air quality management approach to overcome

  3. Heavy metal pollution in surface soils of Pearl River Delta, China.

    Science.gov (United States)

    Jinmei, Bai; Xueping, Liu

    2014-12-01

    Heavy metal pollution is an increasing environmental problem in Chinese regions undergoing rapid economic and industrial development, such as the Pearl River Delta (PRD), southern China. We determined heavy metal concentrations in surface soils from the PRD. The soils were polluted with heavy metals, as defined by the Chinese soil quality standard grade II criteria. The degree of pollution decreased in the order Cd > Cu > Ni > Zn > As > Cr > Hg > Pb. The degree of heavy metal pollution by land use decreased in the order waste treatment plants (WP) > urban land (UL) > manufacturing industries (MI) > agricultural land (AL) > woodland (WL) > water sources (WS). Pollution with some of the metals, including Cd, Cu, Ni, and Zn, was attributed to the recent rapid development of the electronics and electroplating industries. Cd, Hg, and Pb (especially Cd) pose high potential ecological risks in all of the zones studied. The soils posing significantly high and high potential ecological risks from Cd covered 73.3 % of UL, 50 % of MI and WP land, and 48.5 % of AL. The potential ecological risks from heavy metals by land use decreased in the order UL > MI > AL > WP > WL > WS. The control of Cd, Hg, and Pb should be prioritized in the PRD, and emissions in wastewater, residue, and gas discharges from the electronics and electroplating industry should be decreased urgently. The use of chemical fertilizers and pesticides should also be decreased.

  4. Complex Network Simulation of Forest Network Spatial Pattern in Pearl River Delta

    Science.gov (United States)

    Zeng, Y.

    2017-09-01

    Forest network-construction uses for the method and model with the scale-free features of complex network theory based on random graph theory and dynamic network nodes which show a power-law distribution phenomenon. The model is suitable for ecological disturbance by larger ecological landscape Pearl River Delta consistent recovery. Remote sensing and GIS spatial data are available through the latest forest patches. A standard scale-free network node distribution model calculates the area of forest network's power-law distribution parameter value size; The recent existing forest polygons which are defined as nodes can compute the network nodes decaying index value of the network's degree distribution. The parameters of forest network are picked up then make a spatial transition to GIS real world models. Hence the connection is automatically generated by minimizing the ecological corridor by the least cost rule between the near nodes. Based on scale-free network node distribution requirements, select the number compared with less, a huge point of aggregation as a future forest planning network's main node, and put them with the existing node sequence comparison. By this theory, the forest ecological projects in the past avoid being fragmented, scattered disorderly phenomena. The previous regular forest networks can be reduced the required forest planting costs by this method. For ecological restoration of tropical and subtropical in south China areas, it will provide an effective method for the forest entering city project guidance and demonstration with other ecological networks (water, climate network, etc.) for networking a standard and base datum.

  5. Characterizing baseline concentrations, proportions, and processes controlling deposition of river-transported bitumen-associated polycyclic aromatic compounds at a floodplain lake (Slave River Delta, Northwest Territories, Canada).

    Science.gov (United States)

    Elmes, Matthew C; Wiklund, Johan A; Van Opstal, Stacey R; Wolfe, Brent B; Hall, Roland I

    2016-05-01

    Inadequate knowledge of baseline conditions challenges ability for monitoring programs to detect pollution in rivers, especially where there are natural sources of contaminants. Here, we use paleolimnological data from a flood-prone lake ("SD2", informal name) in the Slave River Delta (SRD, Canada), ∼ 500 km downstream of the Alberta oil sands development and the bitumen-rich McMurray Formation to identify baseline concentrations and proportions of "river-transported bitumen-associated indicator polycyclic aromatic compounds" (indicator PACs; Hall et al. 2012) and processes responsible for their deposition. Results show that indicator PACs are deposited in SD2 by Slave River floodwaters in concentrations that are 45 % lower than those in sediments of "PAD31compounds", a lake upstream in the Athabasca Delta that receives Athabasca River floodwaters. Lower concentrations at SD2 are likely a consequence of sediment retention upstream as well as dilution by sediment influx from the Peace River. In addition, relations with organic matter content reveal that flood events dilute concentrations of indicator PACs in SD2 because the lake receives high-energy floods and the lake sediments are predominantly inorganic. This contrasts with PAD31 where floodwaters increase indicator PAC concentrations in the lake sediments, and concentrations are diluted during low flood influence intervals due to increased deposition of lacustrine organic matter. Results also show no significant differences in concentrations and proportions of indicator PACs between pre- (1967) and post- (1980s and 1990 s) oil sands development high flood influence intervals (t = 1.188, P = 0.279, d.f. = 6.136), signifying that they are delivered to the SRD by natural processes. Although we cannot assess potential changes in indicator PACs during the past decade, baseline concentrations and proportions can be used to enhance ongoing monitoring efforts.

  6. A Groundwater flow Model of the Colorado River Delta to Support Riparian Habitat Restoration in Northern Mexico

    Science.gov (United States)

    Maddock, T.; Feirstein, E.; Baird, K. J.; Ajami, H.

    2007-05-01

    Quantification of groundwater flow dynamics and of the interactions among groundwater, surface water, and riparian vegetation, represent key components in the development of a balanced restoration plan for functional riparian ecosystems. A groundwater model was developed using MODFLOW 2000 to support of riparian restoration along the Colorado River Delta (Mexico: Baja California, Sonora). The Colorado River is widely recognized as one of the most modified and allocated rivers in the United States. For over 50 years flows into the Delta were severely reduced by the requirements of an emergent American West. However, subsequent to discharge pulses associated with the filling of Lake Powell, and the increased precipitation that accompanied ENSO cycles, a semblance of a native riparian habitat has been observed in the Delta since the 1980's (Zamora- Arroyo et al. 2001). The Delta and the riparian ecosystems of the region have since become the focus of a substantial body of multidisciplinary research. The research goal is to understand water table dynamics with particular attention to stream-aquifer interactions and groundwater behavior in the root zone. Groundwater reliant transpiration requirements were quantified for a set of dominant native riparian species using the Riparian ET (RIP-ET) package, an improved MODFLOW evapotranspiration (ET) module. RIP-ET simulates ET using a set of eco-physiologically based curves that more accurately represents individual plant species, reflects habitat complexity, and deals spatially with plant and water table distribution. When used in conjunction with a GIS based postprocessor (RIP-GIS.net), RIP-ET provides the basis for mapping groundwater conditions as they relate to user-specified plant groups. This explicit link between groundwater and plant sustainability is a driver to restoration design and allows for scenario modeling of various hydrologic conditions. Groundwater requirements determined in this research will be used by

  7. Pesticides in soil and sediment of a dyke-protected area of the Red River Delta, Vietnam

    Science.gov (United States)

    Braun, Gianna; Bläsing, Melanie; Kruse, Jens; Amelung, Wulf; Renaud, Fabrice; Sebesvari, Zita

    2017-04-01

    Coastal regions are densely populated but at the same time represent important agricultural areas for food production of the growing world population. To sustain high agricultural yields, in monocultures such as permanent rice systems, pesticides are used in high quantity and frequency. While earlier studies monitored the fate of pesticides in paddy rice systems, the overall fate of these compounds is altered nowadays due to the construction of dykes, which are needed in many delta regions to protect them from high tides, storm surges and salt water intrusion such as in the Red River Delta. The dyke system regulates the discharge and water exchange inside the diked area including irrigation channels for the paddy rice production. Local authorities observed increasing pollution towards the sea (highest pollution close to the dykes) and hypothesized that the dyke system would prevent water exchange and thus lead to an accumulation of pollutants within the diked area. Hence, the purpose of this study was to investigate the effect of dykes on pesticide pollution patterns in coastal delta regions of the Red River Delta. The study was conducted in the district Giao Thuy of the Red River Delta, Vietnam. This area is surrounded by a sea and river dyke; both have several inlet and outlet gates to control the water level in the irrigation channels. We determined the pesticide pollution pattern in a diked agricultural area, as well as along salinity gradients in and outside the diked areas. Samples were taken from rice fields and sediments from irrigation channels inside the diked area as well from saline aquaculture fields located outside the dyke. Pesticide analysis was conducted by accelerated solvent extraction (ASE), followed up by the clean-up process described by Laabs et al. (2007) and analyses using gas chromatography coupled with a mass selective detector (MSD). Preliminary results suggest that out of the 26 analysed compounds chlorpyrifos, propiconazole and

  8. Understanding the Value of Satellite Altimetry for Monitoring Water Level Dynamics of Large Rivers in Bangladesh Delta

    Science.gov (United States)

    Hossain, F.; Akbor, S.; Sustainability, Satellites, Water; Environment (Saswe) Research Group

    2010-12-01

    Although transboundary river flow accounts for more than 40% of global surface flow across 145 nations (many of them water-stressed and conflict-prone), most of this flow is difficult to monitor in developing nations at operational timescales. For Bangladesh, this situation is particularly acute because it comprises only 7% of the entire Ganges-Brahmaputra-Meghna basin and is located at the downstream end of the basin. Thus more than 90% of the water is generated in upstream nations and yet this information is hard to obtain in Bangladesh due to lack of transboundary instrumentation or international treaties. This work therefore investigates the value of satellite radar altimetry in detecting the water level changes for large rivers in the Bangladesh Delta. It is founded on the hypothesis that a satellite altimeter can detect water level to the same accuracy for both inside and outside of Bangladesh. First, the river hydraulic model called HEC-RAS (Hydrologic Engineering Center, River Analysis System) is set up and calibrated over Bangladesh using a comprehensive database on in-situ river bathymetry and observed water level records. Next, the calibrated HEC-RAS model is provided boundary flow conditions upstream and downstream of the model domain. At the upstream end where the Ganges, Brahmaputra and Meghan enter Bangladesh, high resolution flow data modeled from a well calibrated hydrologic model called MIKE BASIN is provided as input. The observed tidal flow records of the Meghna estuary near the Bay of Bengal are used as the downstream boundary conditions. HEC-RAS is then used to simulate daily water level data for the period of 2003-2005 for major rivers of Bangladesh. These water level simulations are directly compared with altimeter estimates of water level from the ENVISAT mission. Accuracy of ENVISAT data is characterized as a function of season, flow regime and river type. The important question that this study aims to answer is, “To what extent can

  9. Ecology of Juvenile Salmon in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2008 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Sather, NK; Johnson, GE; Storch, AJ [Pacific Northwest National Laboratory

    2009-07-06

    The tidal freshwater monitoring (TFM) project reported herein is part of the research, monitoring, and evaluation effort developed by the Action Agencies (Bonneville Power Administration, the U.S. Army Corps of Engineers [USACE], and the U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act (ESA) as a result of operation of the Federal Columbia River Power System. The project is being performed under the auspices of the Northwest Power and Conservation Council's Columbia Basin Fish and Wildlife Program (Project No. 2005-001-00). The research is a collaborative effort among the Pacific Northwest National Laboratory, the Oregon Department of Fish and Wildlife, the National Marine Fisheries Service, and the University of Washington. The overarching goal of the TFM project is to bridge the gap in knowledge between tidal freshwater habitats and the early life history attributes of migrating salmon. The research questions include: In what types of habitats within the tidal freshwater area of the Columbia River are juvenile salmon found, when are they present, and under what environmental conditions? What is the ecological contribution of shallow (0-5 m) tidal freshwater habitats to the recovery of ESA-listed salmon in the Columbia River basin? Field data collection for the TFM project commenced in June 2007 and since then has continued monthly at six to nine sites in the vicinity of the Sandy River delta (river kilometer 192-208). While this report includes summary data spanning the 19-month period of study from June 2007 through December 2008, it highlights sampling conducted during calendar year 2008. Detailed data for calendar year 2007 were reported previously. The 2008 research objectives were as follows: (1) Characterize the vegetation composition and percent cover, conventional water quality, water surface elevation, substrate composition, bathymetry, and beach slope at the study sites within the vicinity of the Sandy

  10. Evaluation of a floating fish guidance structure at a hydrodynamically complex river junction in the Sacramento–San Joaquin River Delta, California, USA

    Science.gov (United States)

    Romine, Jason G.; Perry, Russell W.; Pope, Adam C; Stumpner, Paul; Liedtke, Theresa L.; Kumagai, Kevin K; Reeves, Ryan L

    2016-01-01

    Survival of out-migrating juvenile Chinook salmon (Oncorhynchus tshawytscha) in the Sacramento–San Joaquin River delta, California, USA, varies by migration route. Survival of salmonids that enter the interior and southern Delta can be as low as half that of salmonids that remain in the main-stem Sacramento River. Reducing entrainment into the higher-mortality routes, such as Georgiana Slough, should increase overall survival. In spring 2014, a floating fish-guidance structure (FFGS) designed to reduce entrainment into Georgiana Slough was deployed just upstream of the Georgiana Slough divergence. We used acoustic telemetry to evaluate the effect of the FFGS on Chinook entrainment to Georgiana Slough. At intermediate discharge (200–400 m3 s–1), entrainment into Georgiana Slough was five percentage points lower when the FFGS was in the on state (19.1% on; 23.9% off). At higher discharge (>400 m3 s–1), entrainment was higher when the FFGS was in the on state (19.3% on; 9.7% off), and at lower discharge (0–200 m3 s–1) entrainment was lower when the FFGS was in the on state (43.7% on; 47.3% off). We found that discharge, cross-stream fish position, time of day, and proportion of flow remaining in the Sacramento River contributed to the probability of being entrained to Georgiana Slough.

  11. Impact of the Hoa Binh dam (Vietnam) on water and sediment budgets in the Red River basin and delta

    Science.gov (United States)

    Vinh, V. D.; Ouillon, S.; Thanh, T. D.; Chu, L. V.

    2014-10-01

    The Hoa Binh dam (HBD), located on a tributary of the Red River in Vietnam, has a capacity of 9.45 × 109 m3 and was commissioned in December 1988. Although it is important for flood prevention, electricity production and irrigation in northern Vietnam, the Hoa Binh dam has also highly influenced the suspended sediment distribution in the lower Red River basin, in the delta and in the coastal zone. Its impact was analysed from a 50-year data set of water discharge and suspended sediment concentration (1960-2010), and the distribution of water and sediment across the nine mouths of the delta was simulated using the MIKE11 numerical model before and after the dam settlement. Although water discharge at the delta inlet decreased by only 9%, the yearly suspended sediment flux dropped, on average, by 61% at Son Tay near Hanoi (from 119 to 46 × 106 t yr-1). Along the coast, reduced sedimentation rates are coincident with the lower sediment delivery observed since the impoundment of the Hoa Binh dam. Water regulation has led to decreased water discharge in the wet season (-14% in the Red River at Son Tay) and increased water discharge in the dry season (+12% at the same station). The ratios of water and suspended sediment flows, as compared to the total flows in the nine mouths, increased in the northern and southern estuaries and decreased in the central, main Ba Lat mouth. The increasing volume of dredged sediments in the Haiphong harbour is evidence of the silting up of the northern estuary of Cam-Bach Dang. The effect of tidal pumping on enhanced flow occurring in the dry season and resulting from changed water regulation is discussed as a possible cause of the enhanced siltation of the estuary after Hoa Binh dam impoundment.

  12. Stepwise morphological evolution of the active Yellow River (Huanghe) delta lobe (1976-2013): Dominant roles of riverine discharge and sediment grain size

    Science.gov (United States)

    Wu, Xiao; Bi, Naishuang; Xu, Jingping; Nittrouer, Jeffrey A.; Yang, Zuosheng; Saito, Yoshiki; Wang, Houjie

    2017-09-01

    The presently active Yellow River (Huanghe) delta lobe has been formed since 1976 when the river was artificially diverted. The process and driving forces of morphological evolution of the present delta lobe still remain unclear. Here we examined the stepwise morphological evolution of the active Yellow River delta lobe including both the subaerial and the subaqueous components, and illustrated the critical roles of riverine discharge and sediment grain size in dominating the deltaic evolution. The critical sediment loads for maintaining the delta stability were also calculated from water discharge and sediment load measured at station Lijin, the last gauging station approximately 100 km upstream from the river mouth. The results indicated that the development of active delta lobe including both subaerial and subaqueous components has experienced four sequential stages. During the first stage (1976-1981) after the channel migration, the unchannelized river flow enhanced deposition within the channel and floodplain between Lijin station and the river mouth. Therefore, the critical sediment supply calculated by the river inputs obtained from station Lijin was the highest. However, the actual sediment load at this stage (0.84 Gt/yr) was more than twice of the critical sediment load ( 0.35 Gt/yr) for sustaining the active subaerial area, which favored a rapid seaward progradation of the Yellow River subaerial delta. During the second stage (1981-1996), the engineering-facilitated channelized river flow and the increase in median grain size of suspended sediment delivered to the sea resulted in the critical sediment load for keeping the delta stability deceasing to 0.29 Gt/yr. The active delta lobe still gradually prograded seaward at an accretion rate of 11.9 km2/yr at this stage as the annual sediment load at Lijin station was 0.55 Gt/yr. From 1996 to 2002, the critical sediment load further decreased to 0.15 Gt/yr with the sediment grain size increased to 22.5

  13. Occurrence and behavior of pharmaceuticals, steroid hormones, and endocrine-disrupting personal care products in wastewater and the recipient river water of the Pearl River Delta, South China.

    Science.gov (United States)

    Yu, Yiyi; Huang, Qiuxin; Wang, Zhifang; Zhang, Kun; Tang, Caiming; Cui, Jianlan; Feng, Jialiang; Peng, Xianzhi

    2011-04-01

    The occurrence and behavior of β-blockers, antiepileptic drug carbamazepine and its metabolites, X-ray contrast agent iopromide, natural and synthetic hormones, and several groups of hormone-like personal care products (PCPs), including antiseptics (triclocarban, triclosan, and 2-phenylphenol), parabens and bisphenol A, were investigated in municipal wastewater, sewage sludge, and urban river water of the Pearl River Delta, South China. The pharmaceuticals, natural hormones and PCPs were ubiquitously detected in the raw wastewater from a sewage treatment plant (STP). Only triclocarban and triclosan were detected at significant amounts in the dewatered sludge. Iopromide and the PCPs were greatly removed/transformed from the aqueous phase of the wastewater. The β-blockers were only moderately removed/transformed. Carbamazepine passed through the STP almost unchanged. Biodegradation was the dominant process for elimination/transformation of the pharmaceuticals, hormones, and most PCPs in the STP. However, sorption also played an important role in the fate of triclocarban with nearly 50% of the mass load entering the STP ended up and persisted in the dewatered sludge. The pharmaceuticals, estrone, and PCPs were also widely detected in the Pearl River at Guangzhou. Bisphenol A had the highest concentration. The pharmaceutical concentrations in the Pearl River were higher in March than in May, most likely due to less dilution by lower precipitation. The omnipresence and high levels of the pharmaceuticals and PCPs in the Pearl River may be associated with direct discharge of untreated wastewater and pose potential risks to the ecological system.

  14. Impacts of the dam-orientated water-sediment regulation scheme on the lower reaches and delta of the Yellow River (Huanghe): A review

    Science.gov (United States)

    Wang, Houjie; Wu, Xiao; Bi, Naishuang; Li, Song; Yuan, Ping; Wang, Aimei; Syvitski, James P. M.; Saito, Yoshiki; Yang, Zuosheng; Liu, Sumei; Nittrouer, Jeffrey

    2017-10-01

    The water-sediment regulation scheme (WSRS), beginning in 2002, is an unprecedented engineering effort to manage the Yellow River with the aims to mitigate the siltation both in the lower river channel and within the Xiaolangdi Reservoir utilizing the dam-regulated flood water. Ten years after its initial implementation, multi-disciplinary indicators allow us to offer a comprehensive review of this human intervention on a river-coastal system. The WSRS generally achieved its objective, including bed erosion in the lower reaches with increasing capacity for flood discharge and the mitigation of reservoir siltation. However, the WSRS presented unexpected disturbances on the delta and coastal system. Increasing grain size of suspended sediment and decreasing suspended sediment concentration at the river mouth resulted in a regime shift of sediment transport patterns that enhanced the disequilibrium of the delta. The WSRS induced an impulse delivery of nutrients and pollutants within a short period ( 20 days), which together with the altered hydrological cycle, impacted the estuarine and coastal ecosystem. We expect that the sediment yield from the loess region in the future will decrease due to soil-conservation practices, and the lower channel erosion will also decrease as the riverbed armors with coarser sediment. These, in combination with uncertain water discharge concomitant with climate change, increasing water demands and delta subsidence, will put the delta and coastal ocean at high environmental risks. In the context of global change, this work depicts a scenario of human impacts in the river basin that were transferred along the hydrological pathway to the coastal system and remotely transformed the different components of coastal environment. The synthesis review of the WSRS indicates that an integrated management of the river-coast continuum is crucially important for the sustainability of the entire river-delta system. The lessons learned from the WSRS in

  15. Landscape controls and vertical variability of soil organic carbon storage in permafrost-affected soils of the Lena River Delta

    DEFF Research Database (Denmark)

    Siewert, Matthias Benjamin; Hugelius, Gustaf; Heim, Birgit

    2016-01-01

    in the permafrost. The major geomorphological units of a subregion of the Lena River Delta were mapped with a land form classification using a data-fusion approach of optical satellite imagery and digital elevation data to upscale SOC storage. Landscape mean SOC storage is estimated to 19.2 ± 2.0 kg C m− 2. Our...... by thermal-degradation, the recent floodplain and bare alluvial sediments store considerably less SOC in descending order....

  16. Hotspot of glyoxal over the Pearl River delta seen from the OMI satellite instrument: implications for emissions of aromatic hydrocarbons

    OpenAIRE

    Chan Miller, Christopher; Jacob, Daniel J.; González Abad, Gonzalo; Chance, Kelly

    2016-01-01

    The Pearl River delta (PRD) is a densely populated hub of industrial activity located in southern China. OMI (Ozone Monitoring Instrument) satellite observations reveal a large hotspot of glyoxal (CHOCHO) over the PRD that is almost twice as large as any other in Asia. Formaldehyde (HCHO) and NO2 observed by OMI are also high in the PRD but no more than in other urban/industrial areas of China. The CHOCHO hotspot over the PRD can be explained by industrial paint and solvent ...

  17. [Distribution of Regional Pollution and the Characteristics of Vertical Wind Field in the Pearl River Delta].

    Science.gov (United States)

    Liu, Jian; Wu, Dui; Fan, Shao-jia

    2015-11-01

    Based on the data of hourly PM2.5 concentration of 56 environmental monitoring stations and 9 cities over the Pearl River Delta (PRD) region, the distributions of PM2.5 pollution in PRD region were analyzed by systematic cluster analysis and correlational analysis. It was found that the regional pollution could be divided into 3 types. The first type was the pollution occurred in Dongguan, Guangzhou, Foshan and Jiangmen (I type), and the second type was the pollution occurred in Zhongshan, Zhuhai, Shenzhen and Huizhou (II type), while the last type was the pollution only occurred in Zhaoqing (III type). During the study period, they occurred 47, 7 and 128 days, respectively. During events of pollution type I, except Zhuhai, Shenzhen and Huizhou, the PM2.5 concentrations of other cities were generally high, while the PM2.5 concentration in whole PRD region was over 50.0 μg x m(-3) during events of pollution type II. The regions with higher PM2.5 concentration was mainly concentrated in Zhaoqing, Guangzhou and Foshan during events of pollution type III. The wind data from 4 wind profile radars located in PRD region was used to study the characteristics of vertical wind field of these 3 pollution types. It was found that the wind profiles of type I and III were similar that low layer and high layer were controlled by the southeast wind and the southwest wind, respectively. For type II, the low layer and high layer were influenced by northerly wind and westerly wind, respectively. Compared with other types, the wind speed and ventilation index of type II. were much higher, and the variation of wind direction at lower-middle-layer was much smaller. When PRD region was influenced by northerly winds, the PM2.5 concentration in the entire PRD region was higher. When PRD region was controlled by southeast wind, the PM2.5 concentrations of I and II areas were relatively lower, while the pollution in III area was relatively heavier.

  18. Impacts of urbanization on nitrogen deposition in the Pearl River Delta region, China

    Science.gov (United States)

    Wang, X.; Fan, Q.

    2015-12-01

    The Pearl River Delta (PRD) region is one of the most advanced economic districts in China, which has experienced remarkable economic development and urbanization in the past two decades. Accompanied with the rapid economy development and urbanization, the PRD region encountered both severe nitrogen pollution and deposition. In this study, the characteristics of nitrogen deposition and impacts of urbanization on nitrogen deposition in the PRD region were investigated by combining the methods of field study and numerical model. According to the field measurements, the total dry and wet atmospheric deposition of reactive N at a urban site (SYSU) was up to 55.0 kg ha-1 yr-1 in 2010, slightly lower than the results at a rural forest site (DHS) (57.6 kg ha-1 yr-1). Wet deposition was the main form of the total deposition (64-76%). Organic nitrogen (ON) was found to be dominant in the total N deposition, with a contribution of 53% at DHS and 42% at SYSU. NH4+-N and NO3--N accounted for a similar portion of the total N deposition (23-29%). Atmospheric nitrogen deposition was further simulated by using the improved WRF-Chem model. The simulated N deposition flux was high in the north of PRD (i.e., Guangzhou, Foshan, Zhaoqing) and relative low in the east (Huizhou) and south (Zhuhai), with an average N deposition flux of about 24 kg ha-1 yr-1 for the whole PRD. The distribution of N dry deposition was mainly controlled by the concentration of reactive N compounds and precipitation governed the wet deposition distribution. The modeling results also indicate that the PRD area is the source region in which the emissions exceed the deposition while the outside area of the PRD is the receptor region in which the deposition exceeds emissions. The impact of emission change and land use change due to urbanization was also investigated using the WRF-Chem model. The results showed that atmospheric N deposition exhibits a direct response to emission change while the land use change

  19. Aerosol size distribution characteristics of organosulfates in the Pearl River Delta region, China

    Science.gov (United States)

    Kuang, Bin Yu; Lin, Peng; Hu, Min; Yu, Jian Zhen

    2016-04-01

    Organosulfates (OSs) have been detected in various atmospheric environments, but their particle size distribution characteristics are unknown. In this work, we examined their size distributions in ambient aerosols to gain insights into the formation processes. Size-segregated aerosol samples in the range of 0.056-18 μm were collected using a ten-stage impactor at a receptor site in Hong Kong in both summer and winter and in Nansha in the Pearl River Delta in winter. The humic-like substances fraction in the size-segregated samples was isolated and analyzed using electrospray ionization coupled with an Orbitrap Ultra High Resolution Mass Spectrometer. Through accurate mass measurements, ∼190 CHOS and ∼90 CHONS formulas were tentatively identified to be OS compounds. Among them, OS compounds derived from isoprene, α-/β-pinene, and limonene and alkyl OSs having low double bond equivalents (DBE = 0,1) and 0-2 extra O beyond those in -OSO3 were found with high intensity. The biogenic volatile organic compounds-derived OS formulas share a common characteristic with sulfate in that the droplet mode dominated, peaking in either 0.56-1.0 or 1.0-1.8 μm size bin, reflecting sulfate as their common precursor. Most of these OSs have a minor coarse mode, accounting for 0-45%. The presence of OSs on the coarse particles is hypothesized to be a result of OSs on small particle (<0.32 μm) coagulating with coarse particles, as the abundance ratios of OS to non-sea-salt sulfate present on the coarse particles were similar to those on particles <0.32 μm. Among a few pairs of CHONS and CHOS that could be linked up through hydrolysis of a nitrooxy group in the CHONS form (e.g., m/z 294: C10H16O7NS- vs. m/z 249 C10H17O5S- from α/β-pinene, differing by (+H2O-HNO3)), the CHONS compounds had an enhanced coarse mode presence. This could be interpreted as a result of slower hydrolysis of the CHONS compounds on the alkali coarse particles. The low DBE alkyl OS compounds have a

  20. [Response of active nitrogen to salinity in a soil from the Yellow River Delta].

    Science.gov (United States)

    Li, Ling; Qiu, Shao-Jun; Chen, Yin-Ping; Zhao, Xi-Men; Liu, Jing-Tao; Lu, Zhao-Hu

    2014-06-01

    Soil salinity can inhibit the processes of nitrogen cycle, and the active nitrogen is the important indicator to reflect the turnover of nitrogen. A laboratory experiment was conducted to study the effect of soil salinity on the active nitrogen in a soil of the Yellow River Delta incubated aerobically under 25 degrees C for 45 days. Four levels of salinity (S1: 0.1%, S2: 0.5%, S3: 0.9%, S4: 1.3%) were imposed using NaCl (mass fraction), and glucose with or without NH4Cl were added to the soils. NO3(-) -N, NH4(+) -N, total soluble nitrogen (TSN) and microbial biomass nitrogen (MBN) were monitored. Results showed that NO3(-)-N was significantly higher in the low salinity soil (S1, S2) than in the high salinity soil (S3, S4) under the control and with NH4Cl addition, and especially the difference was larger with NH4Cl addition. Comparing with the control, NO3(-) -N was increased significantly in S1 and S2. NO3(-) -N was decreased significantly with glucose addition, and there was no difference among the four salinity soils during the whole incubation period. NH4(+) -N was significantly higher in the high salinity soil (S3, S4) than in the low salinity soil (S1, S2), and it was increased particularly in S4 after day 5. With the addition of NH4Cl, NH4(+) -N was increased in S3 and S4. MBN was higher in the low salinity soil than in the high salinity soil, and it was not increased with NH4Cl addition, though TSN was increased. With glucose addition, MBN was increased by 89.9% - 130.9% in the low salinity soil (S1, S2) and 36.9% - 79.5% in the high salinity soil (S3, S4). It was suggested that soil salinity had influence on N transformation, and high salinity inhibited the transformation and assimilation of N by microorganism. The addition of C depressed the effect of salinity, and improved the microbial activity. The application of organic matter is an effective measure to improve N transformation in saline soils.

  1. Impact of Wind Driven Pond Expansion on Landloss in the Mississippi River Delta Plain

    Science.gov (United States)

    Ortiz, A. C.; Edmonds, D. A.

    2016-12-01

    Wetlands of the Mississippi River Delta Plain (MRDP) have been disappearing over the past century due to decreased sediment load, anthropogenic management, increased subsidence, and accelerating eustatic sea-level rise. These effects can cause landloss by submergence of the wetland surface or by lateral erosion of the edges. Given the economic and ecological importance of the MRDP, it is vital to quantify the relative contribution of each process. Using three year Landsat composites, we created a 33 year time series of land-water maps for the Atchafalaya-Vermillion, Terrebonne, and Barataria watersheds. These three watersheds represent the range of MRDP conditions and anthropogenic impacts. The composite images are the per-pixel 50% average across all bands for all non-cloudy pixels over three years to minimize effects of poor image quality, limited number of images, and bias from floating vegetation on water bodies. The land-water binary images are created using dynamic thresholding based off modified normal difference water index with all land and water bodies smaller than 8 pixels (7,200 m2) removed. On each binary composite image we select and track the 444 ponds that: 1) appear in every composite; 2) have a simple shape; and 3) are expanding. Remarkably, in all basins these ponds show expansion in the south-south-west direction. In particular, Atchafalaya-Vermillion shows expansion to the SSW, WSW, and NNW while Barataria shows expansion in WSW and NNW. We hypothesize that this expansion is caused by enhanced edge erosion from wind-driven waves because pond expansion directions are consistent with wind direction data. The large wind events (10-15 m/s) come from the north and the most frequent wind events (5-10 m/s) come from the south and east. Furthermore, we show a correlation between pond size and magnitude of expansion, which is also consistent with models for pond expansion by wind-waves. We suggest that land loss by edge erosion on the MRDP may be more

  2. Light Absorption of Brown Carbon Aerosol in the Pearl River Delta Region of China

    Science.gov (United States)

    Huang, X.

    2015-12-01

    X.F. Huang, J.F. Yuan, L.M. Cao, J. Cui, C.N. Huang, Z.J. Lan and L.Y. He Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, ChinaCorresponding author. Tel.: +86 755 26032532; fax: +86 755 26035332. E-mail address: huangxf@pku.edu.cn (X. F. Huang). Abstract: The strong spectral dependence of light absorption of brown carbon (BrC) aerosol has been recognized in recent decades. The Absorption Angstrom Exponent (AAE) of ambient aerosol was widely used in previous studies to attribute light absorption of brown carbon at shorter wavelengths, with a theoretical assumption that the AAE of black carbon (BC) aerosol equals to unit. In this study, the AAE method was improved by statistical extrapolation based on ambient measurements in the polluted seasons in typical urban and rural areas in the Pearl River Delta (PRD) region of China. A three-wavelength photoacoustic soot spectrometer (PASS-3) and an aerosol mass spectrometer (AMS) were used to explore the relationship between the ambient measured AAE and the ratio of organic aerosol to BC aerosol, in order to extract the more realistic AAE by pure BC aerosol, which were found to be 0.86, 0.82 and 1.02 at 405nm and 0.70, 0.71, and 0.86 at 532nm in the campaigns of urban-winter, urban-fall, and rural-fall, respectively. Roadway tunnel experiment results further supported the effectiveness of the obtained AAE for pure BC aerosol. In addition, biomass burning experiments proved higher spectral dependence of more-BrC environment and further verified the reliability of the instruments' response. Then, the average light absorption contribution of BrC aerosol was calculated to be 11.7, 6.3 and 12.1% (with total relative uncertainty of 7.5, 6.9 and 10.0%) at 405nm and 10.0, 4.1 and 5.5% (with total relative uncertainty of 6.5, 8.6 and 15.4%) at 532nm of the three campaigns, respectively. These results indicate that the

  3. Land subsidence in the Yangtze River Delta, China revealed from multi-frequency SAR Interferometry

    Science.gov (United States)

    Li, Zhenhong; Motagh, Mahdi; Yu, Jun; Gong, Xulong; Wu, Jianqiang; Zhu, Yefei; Chen, Huogen; Zhang, Dengming; Xu, Yulin

    2014-05-01

    Land subsidence is a major worldwide hazard, and its principal causes are subsurface fluid withdrawal, drainage of organic soils, sinkholes, underground mining, hydrocompaction, thawing permafrost, and natural consolidation. Land subsidence causes many problems including: damage to public facilities such as bridges, roads, railroads, electric power lines, underground pipes; damage to private and public buildings; and in some cases of low-lying land, can increase the risk of coastal flooding from storm surges and rising sea-levels. In China, approximately 48600 km2 of land, an area roughly 30 times of the size of the Greater London, has subsided (nearly 50 cities across 16 provinces), and the annual direct economic loss is estimated to be more than RMB 100 million (~12 million). It is believed that the Suzhou-Wuxi-Changzhou region within the Yangtze River Delta is the most severely affected area for subsidence hazards in China. With its global coverage and all-weather imaging capability, Interferometric SAR (InSAR) is revolutionizing our ability to image the Earth's surface and the evolution of its shape over time. In this paper, an advanced InSAR time series technique, InSAR TS + AEM, has been employed to analysed ERS (C-band), Envisat (C-band) and TerraSAR-X (X-band) data collected over the Suzhou-Wuxi-Changzhou region during the period from 1992 to 2013. Validation with precise levelling and GPS data suggest: (1) the accuracy of the InSAR-derived mean velocity measurements is 1-3 mm/yr; (2) InSAR-derived displacements agreed with precise levelling with root mean square errors around 5 mm. It is evident that InSAR TS + AEM can be used to image the evolution of deformation patterns in the Suzhou-Wuxi-Changzhou region over time: the maximum mean velocity decreased from ~12 cm/yr during the period of 1992-1993 to ~2 cm/yr in 2003-2013. This is believed to be a result of the prohibition of groundwater use carried out by Jiangsu provincial government. The combination

  4. Reservoir impacts downstream in highly regulated river basins: the Ebro delta and the Guadalquivir estuary in Spain

    Science.gov (United States)

    Polo, María J.; Rovira, Albert; García-Contreras, Darío; Contreras, Eva; Millares, Agustín; Aguilar, Cristina; Losada, Miguel A.

    2016-05-01

    Regulation by reservoirs affects both the freshwater regime and the sediment delivery at the area downstream, and may have a significant impact on water quality in the final transitional water bodies. Spain is one the countries with more water storage capacity by reservoirs in the world. Dense reservoir networks can be found in most of the hydrographic basins, especially in the central and southern regions. The spatial redistribution of the seasonal and annual water storage in reservoirs for irrigation and urban supply, mainly, has resulted in significant changes of water flow and sediment load regimes, together with a fostered development of soil and water uses, with environmental impacts downstream and higher vulnerability of these areas to the sea level rise and drought occurrence. This work shows these effects in the Guadalquivir and the Ebro River basins, two of the largest regulated areas in Spain. The results show a 71 % decrease of the annual freshwater input to the Guadalquivir River estuary during 1930-2014, an increase of 420 % of the irrigated area upstream the estuary, and suspended sediment loads up to 1000 % the initial levels. In the Ebro River delta, the annual water yield has decreased over a 30 % but, on the contrary, the big reservoirs are located in the main stream, and the sediment load has decreased a 99 %, resulting in a delta coastal regression up to 10 m per year and the massive presence of macrophytes in the lower river. Adaptive actions proposed to face these impacts in a sea level rise scenario are also analyzed.

  5. Integrating active restoration with environmental flows to improve native riparian tree establishment in the Colorado River Delta

    Science.gov (United States)

    Schlatter, Karen; Grabau, Matthew R.; Shafroth, Patrick B.; Zamora-Arroyo, Francisco

    2017-01-01

    Drastic alterations to river hydrology, land use change, and the spread of the nonnative shrub, tamarisk (Tamarix spp.), have led to the degradation of riparian habitat in the Colorado River Delta in Mexico. Delivery of environmental flows to promote native cottonwood (Populus spp.) and willow (Salix spp.) recruitment in human-impacted riparian systems can be unsuccessful due to flow-magnitude constraints and altered abiotic–biotic feedbacks. In 2014, an experimental pulse flow of water was delivered to the Colorado River in Mexico as part of the U.S.-Mexico binational agreement, Minute 319. We conducted a field experiment to assess the effects of vegetation removal, seed augmentation, and environmental flows, separately and in combination, on germination and first-year seedling establishment of cottonwood, willow, and tamarisk at five replicate sites along 5 river km. The relatively low-magnitude flow deliveries did not substantively restore natural fluvial processes of erosion, sediment deposition, and vegetation scour, but did provide wetted surface soils, shallow groundwater, and low soil salinity. Cottonwood and willow only established in wetted, cleared treatments, and establishment was variable in these treatments due to variable site conditions and inundation duration and timing. Wetted soils, bare surface availability, soil salinity, and seed availability were significant factors contributing to successful cottonwood and willow germination, while soil salinity and texture affected seedling persistence over the growing season. Tamarisk germinated and persisted in a wider range of environmental conditions than cottonwood and willow, including in un-cleared treatment areas. Our results suggest that site management can increase cottonwood and willow recruitment success from low-magnitude environmental flow events, an approach that can be applied in other portions of the Delta and to other human-impacted riparian systems across the world with similar

  6. High spatial patchiness of methane concentrations over the flat landscape of the Ebro River Delta (NW Mediterranean)

    Science.gov (United States)

    Morguí, J.-A.; Rodó, X.; Curcoll, R.; Agueda, A.; Sánchez, L.; Occhipinti, P.; Nofuentes, M.; Arias, R.; Batet, O.

    2012-04-01

    With the aim of evaluate the role of a different water management on greenhouse gases (GHGs) at each side of the Ebro River Delta, five points were chosen to be sampled for GHGs for studying their spatial variability along diurnal cycles. The daily schedule for sampling was starting one day at the evening/sunset, followed by the next day dawn sampling, and eventually closing the cycle at the evening/sunset. Samples are been taken along the seasonal cycle to cope with the main rice works: seeding, growing, flourishing, maturation, harvesting, fields flooding and soil aeration before new seeding. The Ebre River Delta terrain is covered in its 200 km2 with the same agroecosystem (paddy fields) at the two riversides, and natural lagoons and marshes are found along the shoreline. The five spots to be sampled were selected to represent all these habitats at each side of the Delta; one is close to paddy fields, another one to the lagoons, and the fifth one to the river embankments up the river, with a pentagonal shape. Continuous measurements (CO2, CH4, H2O) following radial paths transects of the pentagon were performed with a Cavity Ring-Down Spectroscopy (CRDS) analyser mounted on a car. The air inlet was held in front of the car, at forty cm above ground, with a little buffer to filter particles. Due to the constraints imposed by this buffer, every measurement was copying for a track of 30 m, for a 60 km/hour car speed. Flasks for GHGs (CO2, CH4, CO, N20) analyses by Gas Chromatography were taken at every spot with the car engine stopped while the CRDS analyzer was measuring yet, in order to compare results. Ebre River Delta rice cultures management is usually characterized for maintaining the paddies flooded after the harvesting of rice to giving enough aquatic life for feeding the migratory birds. Only during the previous time to seed the rice, the fields are dried. Nevertheless, two years ago, the left side of the riversides is being dried during winter to prevent

  7. Modeling the mass flux budgets of water and suspended sediments for the river network and estuary in the Pearl River Delta, China

    Science.gov (United States)

    Hu, Jiatang; Li, Shiyu; Geng, Bingxu

    2011-11-01

    A coupled physical and sediment transport model was used to study the mass flux budgets of water and suspended sediments in the Pearl River De