WorldWideScience

Sample records for modeling rivers lakes

  1. Mathematical model for flood routing in Jingjiang River and Dongting Lake network

    Directory of Open Access Journals (Sweden)

    Zuo-tao XIE

    2012-09-01

    Full Text Available The main stream of the Yangtze River, Dongting Lake, and the river network in the Jingjiang reach of the Yangtze River constitute a complex water system. This paper develops a one-dimensional (1-D mathematical model for flood routing in the river network of the Jingjiang River and Dongting Lake using the explicit finite volume method. Based on observed data during the flood periods in 1996 and 1998, the model was calibrated and validated, and the results show that the model is effective and has high accuracy. In addition, the one-dimensional mathematical model for the river network and the horizontal two-dimensional (2-D mathematical model for the Jingjiang flood diversion area were coupled to simulate the flood process in the Jingjiang River, Dongting Lake, and the Jingjiang flood diversion area. The calculated results of the coupled model are consistent with the practical processes. Meanwhile, the results show that the flood diversion has significant effects on the decrease of the peak water level at the Shashi and Chenjiawan hydrological stations near the flood diversion gates, and the effect is more obvious in the downstream than in the upstream.

  2. HYDROLOGIC MODELLING OF KATSINA-ALA RIVER BASIN: AN EMERGING SCENARIO FROM LAKE NYOS THREAT

    Directory of Open Access Journals (Sweden)

    J. O. Akinyede

    2012-07-01

    Full Text Available Understanding the hydrologic system surrounding crater lakes is of great importance for prevention of flooding damages, conservation of ecological environment, and assessment of socio-economic impact of dam failure on the civilians in the downstream regions. Lake Nyos is a crater lake formed by volcanic activities at the Oku volcanic field on the Cameroon Volcanic Line. It is a freshwater lake with a maximum depth of 200 meter. In 1986, a limnic eruption at the lake emitted 1.6 million tonnes of carbon dioxide from the bottom of saturated water into the air and suffocated up to 1,800 people and 3,500 livestock at nearby villages. The lake waters are held in place by a natural dam composed of loosely consolidated volcanic rock, which is now at the verge of collapse due to accelerated erosion. This study was carried out to determine the flood risks and vulnerability of population and infrastructure along Katsina-Ala drainage basins. The project integrated both satellite images and field datasets into a hydrologic model for Katsina-Ala River Basin and its vicinity including the Lake Nyos. ArcHydro was used to construct a hydrologic database as 'data models' and MIKE SHE was employed to conduct hydrologic simulations. Vulnerable infrastructures, population and socio-economic activities were identified to assist the Federal and State governments in disaster mitigation and management plans. The result of the project provides comprehensive knowledge of hydrologic system of Katsina-Ala drainage basin to mitigate potential future disasters from a potential dam failure and manage water resources against such disasters.

  3. Ecosystem approach to water resources management using the MIKE 11 modeling system in the Strymonas River and Lake Kerkini.

    Science.gov (United States)

    Doulgeris, Charalampos; Georgiou, Pantazis; Papadimos, Dimitris; Papamichail, Dimitris

    2012-02-01

    The ability to apply an ecosystem approach to the Strymonas River catchment was investigated using the MIKE 11 modeling system for the simulation of surface water. The Strymonas River catchment is shared mainly between Bulgaria and Greece. The river feeds the artificial Lake Kerkini, a significant wetland ecosystem, and further downstream it outflows to the Gulf of Strymonikos, whose estuary ecosystem is very important for fisheries, biodiversity and tourism. MIKE 11-NAM was used for the simulation of rainfall-runoff process in the Strymonas River catchment and MIKE 11-HD was used to simulate the unsteady flow of the Strymonas River and to apply management rules based on the water level of Lake Kerkini. Two water level management scenarios were investigated. The first scenario referred to the mean daily-observed water level of Lake Kerkini between 1986 and 2006, and the second scenario represented adjustments necessary to fulfill the lake's ecosystem requirements. Under the current water level management practices (Scenario 1), the Strymonas River-Lake Kerkini system has enough water to fulfill its Irrigation Water Requirements (IWR) in normal and wet years while a slight deficit is appeared in dry years; however, both Lake Kerkini and the Strymonas River estuary ecosystems are subject to pressures, since reduction of the forest area has been recorded. Applying the ecosystem approach (Scenario 2), the protection of the riparian forest of Lake Kerkini is achieved while in normal and wet years the IWR are fulfilled and the deficit of the IWR is increased in dry years. Compared to Scenario 1, the pressure of the Strymonas River estuary ecosystem is slightly increased.

  4. Forecasting Shaharchay River Flow in Lake Urmia Basin using Genetic Programming and M5 Model Tree

    Directory of Open Access Journals (Sweden)

    S. Samadianfard

    2017-01-01

    Full Text Available Introduction: Precise prediction of river flows is the key factor for proper planning and management of water resources. Thus, obtaining the reliable methods for predicting river flows has great importance in water resource engineering. In the recent years, applications of intelligent methods such as artificial neural networks, fuzzy systems and genetic programming in water science and engineering have been grown extensively. These mentioned methods are able to model nonlinear process of river flows without any need to geometric properties. A huge number of studies have been reported in the field of using intelligent methods in water resource engineering. For example, Noorani and Salehi (23 presented a model for predicting runoff in Lighvan basin using adaptive neuro-fuzzy network and compared the performance of it with neural network and fuzzy inference methods in east Azerbaijan, Iran. Nabizadeh et al. (21 used fuzzy inference system and adaptive neuro-fuzzy inference system in order to predict river flow in Lighvan river. Khalili et al. (13 proposed a BL-ARCH method for prediction of flows in Shaharchay River in Urmia. Khu et al. (16 used genetic programming for runoff prediction in Orgeval catchment in France. Firat and Gungor (11 evaluated the fuzzy-neural model for predicting Mendes river flow in Turkey. The goal of present study is comparing the performance of genetic programming and M5 model trees for prediction of Shaharchay river flow in the basin of Lake Urmia and obtaining a comprehensive insight of their abilities. Materials and Methods: Shaharchay river as a main source of providing drinking water of Urmia city and agricultural needs of surrounding lands and finally one of the main input sources of Lake Urmia is quite important in the region. For obtaining the predetermined goals of present study, average monthly flows of Shaharchay River in Band hydrometric station has been gathered from 1951 to 2011. Then, two third of mentioned

  5. Global Lake and River Ice Phenology Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Global Lake and River Ice Phenology Database contains freeze and thaw/breakup dates as well as other descriptive ice cover data for 865 lakes and rivers in the...

  6. Modeling chlorophyll-a and dissolved oxygen concentration in tropical floodplain lakes (Paraná River, Brazil).

    Science.gov (United States)

    Rocha, R R A; Thomaz, S M; Carvalho, P; Gomes, L C

    2009-06-01

    The need for prediction is widely recognized in limnology. In this study, data from 25 lakes of the Upper Paraná River floodplain were used to build models to predict chlorophyll-a and dissolved oxygen concentrations. Akaike's information criterion (AIC) was used as a criterion for model selection. Models were validated with independent data obtained in the same lakes in 2001. Predictor variables that significantly explained chlorophyll-a concentration were pH, electrical conductivity, total seston (positive correlation) and nitrate (negative correlation). This model explained 52% of chlorophyll variability. Variables that significantly explained dissolved oxygen concentration were pH, lake area and nitrate (all positive correlations); water temperature and electrical conductivity were negatively correlated with oxygen. This model explained 54% of oxygen variability. Validation with independent data showed that both models had the potential to predict algal biomass and dissolved oxygen concentration in these lakes. These findings suggest that multiple regression models are valuable and practical tools for understanding the dynamics of ecosystems and that predictive limnology may still be considered a powerful approach in aquatic ecology.

  7. Nutrient delivery to Lake Winnipeg from the Red-Assiniboine River Basin – A binational application of the SPARROW model

    Science.gov (United States)

    Benoy, Glenn A; Jenkinson, R. Wayne; Robertson, Dale; Saad, David A.

    2016-01-01

    Excessive phosphorus (TP) and nitrogen (TN) inputs from the Red–Assiniboine River Basin (RARB) have been linked to eutrophication of Lake Winnipeg; therefore, it is important for the management of water resources to understand where and from what sources these nutrients originate. The RARB straddles the Canada–United States border and includes portions of two provinces and three states. This study represents the first binationally focused application of SPAtially Referenced Regressions on Watershed attributes (SPARROW) models to estimate loads and sources of TP and TN by jurisdiction and basin at multiple spatial scales. Major hurdles overcome to develop these models included: (1) harmonization of geospatial data sets, particularly construction of a contiguous stream network; and (2) use of novel calibration steps to accommodate limitations in spatial variability across the model extent and in the number of calibration sites. Using nutrient inputs for a 2002 base year, a RARB TP SPARROW model was calibrated that included inputs from agriculture, forests and wetlands, wastewater treatment plants (WWTPs) and stream channels, and a TN model was calibrated that included inputs from agriculture, WWTPs and atmospheric deposition. At the RARB outlet, downstream from Winnipeg, Manitoba, the majority of the delivered TP and TN came from the Red River Basin (90%), followed by the Upper Assiniboine River and Souris River basins. Agriculture was the single most important TP and TN source for each major basin, province and state. In general, stream channels (historically deposited nutrients and from bank erosion) were the second most important source of TP. Performance metrics for the RARB SPARROW model are similarly robust compared to other, larger US SPARROW models making it a potentially useful tool to address questions of where nutrients originate and their relative contributions to loads delivered to Lake Winnipeg.

  8. Calibration of a transient transport model to tritium measurements in rivers and streams in the Western Lake Taupo catchment, New Zealand

    OpenAIRE

    Gusyev, M. A.; Toews, M.; U. Morgenstern; Stewart, M.; C. Daughney; Hadfield, J.

    2012-01-01

    Here we present a general approach of calibrating transient transport models to tritium concentrations in river waters developed for the MT3DMS/MODFLOW model of the Western Lake Taupo catchment, New Zealand. Tritium is a time-dependent tracer with radioactive half-life of 12.32 yr. In the transport model, the tritium input (measured in rain) passes through the groundwater system, and the modelled tritium concentrations are compared to the measured tritium concentrations in the river outl...

  9. A subfossil chironomid-total phosphorus inference model for lakes in the middle and lower reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    ZHANG Enlou; Alan Bedford; Richard Jones; SHEN Ji; WANG Sumin; TANG Hongqu

    2006-01-01

    The results of an investigation into the relationship between surface sediment subfossil chironomid distribution and water quality are presented. Data from 30 lakes in the middle and lower reaches of the Yangtze River indicate that the nutrient gradient was the major factor affecting the distribution of chironomids across these sites. Canonical correspondence analysis (CCA) revealed that of 12 summer water environmental variables, total Phosphorus was most important, accounting for 20.1% of the variance in the chironomid data. This was significant enough to allow the development of quantitative inference models. A TP inference model was developed using weighted averaging (WA), partial least squares (PLS) and weighted averaging partial least squares (WA-PLS). An optimal two-component WA-PLS model provided a high jack-knifed coefficient of prediction for conductivity r 2jack = 0.76, with a low root mean squared error of prediction (RMSEPjack = 0.13). Using this model it is possible to produce long-term quantitative records of past water quality for lacustrine sites across the middle and lower reaches of the Yangtze River, which has important implications for future lake management and ecological restoration.

  10. Prediction of runoff and discharge in the Simiyu River (tributary of Lake Victoria, Tanzania using the WetSpa model

    Directory of Open Access Journals (Sweden)

    J. Rwetabula

    2007-04-01

    Full Text Available A spatially distributed hydrologic model (WetSpa is used to estimate daily river water discharge in the Simiyu river a tributary of Lake Victoria, Tanzania. The model combines topography, landuse and soil maps, and observed daily meteorological time series to predict discharge hydrographs and the spatial distribution of hydrological parameters in the catchment. The elevations in the catchment range from 2000 to 1100 m at the outlet, with average slope of 1.4%. The dominant landuse types are, wasteland, grassland, bushland, cultivated land, and a very small area is covered by surface water. The dominant soil types are sandy loam, followed by sandy clay loam, clay loam, clay, loam and sandy clay. There are two distinctive seasons in the Simiyu catchment. Short rains mainly in November, December and January, and long rains in March to May, resulting in a total average annual precipitation of 700 to 1000 mm. The annual potential evapotranspiration is about 1300 mm, and the river discharge at the catchment outlet ranges from 0 to about 200 m3/s. Global parameters of the model are calibrated using three years of daily observed discharge values measured at the mouth of the river at Lake Victoria. The estimated average travel time of the runoff to the outlet of the catchment is about 2.4 d and maximum 8 d for the most remote areas. The model results also show that the surface runoff and interflow provide respectively 38.6% and 61.4% of the total runoff, while the contribution of groundwater drainage is nil. The absence of groundwater drainage is probably due to the high evaporation demand of the atmosphere, which accounts for about 90% of the total precipitation being lost by evapotranspiration. The annual water balance estimated with the model reveals that the total outflow to Lake Victoria is about 500×106 m3 per year, which occurs mainly in the wet seasons, i.e. from March to May and from November to January. The

  11. DISSOLVED OXYGEN MODELLING USING ARTIFICIAL NEURAL NETWORK: A CASE OF RIVER NZOIA, LAKE VICTORIA BASIN, KENYA

    Directory of Open Access Journals (Sweden)

    Edwin Kimutai Kanda

    2016-11-01

    Full Text Available River Nzoia in Kenya, due to its role in transporting industrial and municipal wastes in addition to agricultural runoff to Lake Victoria, is vulnerable to pollution. Dissolved oxygen is one of the most important indicators of water pollution. Artificial neural network (ANN has gained popularity in water quality forecasting. This study aimed at assessing the ability of ANN to predict dissolved oxygen using four input variables of temperature, turbidity, pH and electrical conductivity. Multilayer perceptron network architecture was used in this study. The data consisted of 113 monthly values for the input variables and output variable from 2009–2013 which were split into training and testing datasets. The results obtained during training and testing were satisfactory with R2 varying from 0.79 to 0.94 and RMSE values ranging from 0.34 to 0.64 mg/l which imply that ANN can be used as a monitoring tool in the prediction of dissolved oxygen for River Nzoia considering the non-correlational relationship of the input and output variables. The dissolved oxygen values follow seasonal trend with low values during dry periods.

  12. Physical processes of thermokarst lakes in the continuous permafrost zone of northern Siberia – observations and modeling (Lena River Delta, Siberia

    Directory of Open Access Journals (Sweden)

    J. Boike

    2015-04-01

    Full Text Available The thermal regimes of five lakes located within the continuous permafrost zone of northern Siberia (Lena River Delta have been investigated using hourly water temperature and water level records covering a three year period (2009–2012, together with bathymetric survey data. The lakes included thermokarst lakes located on Holocene river terraces that may be connected to Lena River water during spring flooding, and a thermokarst lake located on deposits of the Pleistocene Ice Complex. The data were used for numerical modeling with FLake software, and also to determine the physical indices of the lakes. The lakes vary in area, depths and volumes. The winter thermal regime is characterized by an ice cover up to 2 m thick that survives for more than 7 months of the year, from October until about mid-June. Lake-bottom temperatures increase at the start of the ice-covered period due to upward-directed heat flux from the underlying thawed sediment. The effects of solar radiation return prior to ice break-up, effectively warming the water beneath the ice cover and inducing convective mixing. Ice break-up starts the beginning of June and takes until the middle or end of June for completion. Mixing occurs within the entire water column from the start of ice break-up and continues during the ice-free periods, as confirmed by the Wedderburn numbers. Some of the lakes located closest to the Lena River are subjected to varying levels of spring flooding with river water, on an annual basis. Numerical modeling using FLake software indicates that the vertical heat flux across the bottom sediment tends towards an annual mean of zero, with maximum downward fluxes of about 5 W m−2 in summer and with heat released back into the water column at a~rate of less than 1 W m−2 during the ice-covered period. The lakes are shown to be efficient heat absorbers and effectively distribute the heat through mixing. Monthly bottom water temperatures during the ice

  13. Calibration of a transient transport model to tritium measurements in rivers and streams in the Western Lake Taupo catchment, New Zealand

    Directory of Open Access Journals (Sweden)

    M. A. Gusyev

    2012-08-01

    Full Text Available Here we present a general approach of calibrating transient transport models to tritium concentrations in river waters developed for the MT3DMS/MODFLOW model of the Western Lake Taupo catchment, New Zealand. Tritium is a time-dependent tracer with radioactive half-life of 12.32 yr. In the transport model, the tritium input (measured in rain passes through the groundwater system, and the modelled tritium concentrations are compared to the measured tritium concentrations in the river outlets for the Waihaha, Whanganui, Whareroa, Kuratau and Omori river catchments from 2000–2007. For the Kuratau River, tritium was also measured between 1960 and 1970, which allowed us to fine-tune the transport model. In order to incorporate all surface flows from rivers to small streams, an 80 m uniform grid cell size was selected in the steady-state MODFLOW model for the model area of 1072 km2. The groundwater flow model was first calibrated to groundwater levels and stream flow observations. Then, the transport model was calibrated to the measured tritium concentrations in the river waters. The MT3DMS model results show good agreement with the measured tritium values in all five river catchments. Finally, the calibrated MT3DMS model is applied to simulate groundwater ages that are used to construct groundwater age distributions for the river catchments.

  14. DNR 100K Lakes and Rivers

    Data.gov (United States)

    Minnesota Department of Natural Resources — Polygons representing hydrographic features (lakes, ponds, some rivers, and open water areas) originating from the USGS 1:100,000 (100K)DLG (Digital Line Graph)...

  15. Influence of wind and lake morphometry on the interaction between two rivers entering a stratified lake

    Science.gov (United States)

    Morillo, S.; Imberger, J.; Antenucci, J.P.; Woods, P.F.

    2008-01-01

    The interaction of two rivers flowing into Coeur d'Alene Lake (United States) was investigated with a field experiment and three-dimensional numerical simulations. The focus was on the influence of basin morphology, wind speed, and wind direction on the fate and transport of the inflowing water. Data from the field campaign showed that intrusions from the two rivers propagated into the lake at different depths, with the trace element polluted Coeur d'Alene River flowing into the lake above the trace element poor and nutrient rich St. Joe River inflow. The inflows initially intruded horizontally into the lake at their level of neutral buoyancy and later mixed vertically. Model results revealed that, as the intrusions entered the main lake basin, a forced horizontal mode-two basin-scale internal wave interacted with the intrusions to frequently siphon them into the lake proper and where rapid vertical mixing followed. The results serve to show how detailed transport and mixing patterns in a lake can have important consequences for the plankton ecology in the lake. ?? 2008 ASCE.

  16. Mississippi River Headwaters Lakes in Minnesota

    Science.gov (United States)

    1990-10-01

    TABLE .4 IMPACTS OF EXAMPLE 3 - Supplemental Releases (330 cfs) From Gull, Sandy, and Pine River Lakes To Cause Equal Drc -, i- . Levels; Only These...areas to be affected lie. The hearing shall be conducted by the commissioner or a duly appointed referee . All interested parties shall have an

  17. 33 CFR 207.380 - Red Lake River, Minn.; logging regulations for portion of river above Thief River Falls.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Red Lake River, Minn.; logging regulations for portion of river above Thief River Falls. 207.380 Section 207.380 Navigation and Navigable... Red Lake River, Minn.; logging regulations for portion of river above Thief River Falls. (a)...

  18. 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.

  19. Modelling the impact of prescribed global warming on water resources of headwater catchments of the Irrawaddy River and their implications for Loktak Lake, northeast India

    Directory of Open Access Journals (Sweden)

    C. R. Singh

    2010-05-01

    Full Text Available Climate change is likely to have major implications for wetland ecosystems, which will include altered water level regimes due to modifications in local and catchment hydrology. However, substantial uncertainty exists in the precise impacts of climate change on wetlands due in part due to uncertainty in GCM projections. This paper explores the impacts of climate change upon river discharge within three sub-catchments of Loktak Lake, an internationally important wetland in northeast India. This is achieved by running pattern-scaled GCM output through distributed hydrological models (developed using MIKE SHE of each sub-catchment. The impacts of climate change upon water levels within Loktak Lake are subsequently investigated using a water balance model. Two groups of climate change scenarios are investigated. Group 1 uses results from seven different GCMs for an increase in global mean temperature of 2 °C, the purported threshold of "dangerous" climate change, whilst Group 2 is based on results from the HadCM3 GCM for increases in global mean temperature between 1 °C and 6 °C. Results from the Group 1 scenarios show varying responses between the three sub-catchments. The majority of scenario-sub-catchment combinations (13 out of 21 indicate increases in discharge which vary from <1% to 42% although, in some cases, discharge decreases by as much as 20%. Six of the GCMs suggest overall increases in river flow to Loktak Lake (2–27% whilst the other results in a modest (6% decline. In contrast, the Group 2 scenarios lead to an almost linear increase in total river flow to Loktak Lake with increasing temperature (up to 27% for 6 °C, although two sub-catchments experience reductions in mean discharge for the smallest temperature increases. In all but one Group 1 scenario, and all the Group 2 scenarios, Loktak Lake water levels are higher, regularly reaching the top of a downstream hydropower barrage that impounds the lake and necessitating the

  20. Coupled impacts of climate and land use change across a river-lake continuum: insights from an integrated assessment model of Lake Champlain’s Missisquoi Basin, 2000-2040

    Science.gov (United States)

    Zia, Asim; Bomblies, Arne; Schroth, Andrew W.; Koliba, Christopher; Isles, Peter D. F.; Tsai, Yushiou; Mohammed, Ibrahim N.; Bucini, Gabriela; Clemins, Patrick J.; Turnbull, Scott; Rodgers, Morgan; Hamed, Ahmed; Beckage, Brian; Winter, Jonathan; Adair, Carol; Galford, Gillian L.; Rizzo, Donna; Van Houten, Judith

    2016-11-01

    Global climate change (GCC) is projected to bring higher-intensity precipitation and higher-variability temperature regimes to the Northeastern United States. The interactive effects of GCC with anthropogenic land use and land cover changes (LULCCs) are unknown for watershed level hydrological dynamics and nutrient fluxes to freshwater lakes. Increased nutrient fluxes can promote harmful algal blooms, also exacerbated by warmer water temperatures due to GCC. To address the complex interactions of climate, land and humans, we developed a cascading integrated assessment model to test the impacts of GCC and LULCC on the hydrological regime, water temperature, water quality, bloom duration and severity through 2040 in transnational Lake Champlain’s Missisquoi Bay. Temperature and precipitation inputs were statistically downscaled from four global circulation models (GCMs) for three Representative Concentration Pathways. An agent-based model was used to generate four LULCC scenarios. Combined climate and LULCC scenarios drove a distributed hydrological model to estimate river discharge and nutrient input to the lake. Lake nutrient dynamics were simulated with a 3D hydrodynamic-biogeochemical model. We find accelerated GCC could drastically limit land management options to maintain water quality, but the nature and severity of this impact varies dramatically by GCM and GCC scenario.

  1. Treating floodplain lakes of large rivers as study units for variables that vary within lakes; an evaluation using chlorophyll a and inorganic suspended solids data from floodplain lakes of the Upper Mississippi River

    Science.gov (United States)

    Gray, B.R.; Rogala, J.R.; Houser, J.N.

    2013-01-01

    Contiguous floodplain lakes ('lakes') have historically been used as study units for comparative studies of limnological variables that vary within lakes. The hierarchical nature of these studies implies that study variables may be correlated within lakes and that covariate associations may differ not only among lakes but also by spatial scale. We evaluated the utility of treating lakes as study units for limnological variables that vary within lakes based on the criteria of important levels of among-lake variation in study variables and the observation of covariate associations that vary among lakes. These concerns were selected, respectively, to ensure that lake signatures were distinguishable from within-lake variation and that lake-scale effects on covariate associations might provide inferences not available by ignoring those effects. Study data represented chlorophyll a (CHL) and inorganic suspended solids (ISS) data from lakes within three reaches of the Upper Mississippi River. Sampling occurred in summer from 1993 through 2005 (except 2003); numbers of lakes per reach varied from 7 to 19, and median lake area varied from 53 to 101 ha. CHL and ISS levels were modelled linearly, with lake, year and lake x year effects treated as random. For all reaches, the proportions of variation in CHL and ISS attributable to differences among lakes (including lake and lake x year effects) were substantial (range: 18%-73%). Finally, among-lake variation in CHL and ISS was strongly associated with covariates and covariate effects that varied by lakes or lake-years (including with vegetation levels and, for CHL, log(ISS)). These findings demonstrate the utility of treating floodplain lakes as study units for the study of limnological variables and the importance of addressing hierarchy within study designs when making inferences from data collected within floodplain lakes.

  2. CryoSat-2 Altimetry Applications over Rivers and Lakes

    Directory of Open Access Journals (Sweden)

    Liguang Jiang

    2017-03-01

    Full Text Available Monitoring the variation of rivers and lakes is of great importance. Satellite radar altimetry is a promising technology to do this on a regional to global scale. Satellite radar altimetry data has been used successfully to observe water levels in lakes and (large rivers, and has also been combined with hydrologic/hydrodynamic models. Except CryoSat-2, all radar altimetry missions have been operated in conventional low resolution mode with a short repeat orbit (35 days or less. CryoSat-2, carrying a Synthetic Aperture Radar (SAR altimeter, has a 369-day repeat and a drifting ground track pattern and provides new opportunities for hydrologic research. The narrow inter-track distance (7.5 km at the equator makes it possible to monitor many lakes and rivers and SAR mode provides a finer along-track resolution, higher return power and speckle reduction through multi-looks. However, CryoSat-2 challenges conventional ways of dealing with satellite inland water altimetry data because virtual station time series cannot be directly derived for rivers. We review the CryoSat-2 mission characteristics, data products, and its use and perspectives for inland water applications. We discuss all the important steps in the workflow for hydrologic analysis with CryoSat-2, and conclude with a discussion of promising future research directions.

  3. Application of the FluEgg model to predict transport of Asian carp eggs in the Saint Joseph River (Great Lakes tributary)

    Science.gov (United States)

    Garcia, Tatiana; Murphy, Elizabeth A.; Jackson, P. Ryan; Garcia, Marcelo H.

    2015-01-01

    The Fluvial Egg Drift Simulator (FluEgg) is a three-dimensional Lagrangian model that simulates the movement and development of Asian carp eggs until hatching based on the physical characteristics of the flow field and the physical and biological characteristics of the eggs. This tool provides information concerning egg development and spawning habitat suitability including: egg plume location, egg vertical and travel time distribution, and egg-hatching risk. A case study of the simulation of Asian carp eggs in the Lower Saint Joseph River, a tributary of Lake Michigan, is presented. The river hydrodynamic input for FluEgg was generated in two ways — using hydroacoustic data and using HEC-RAS model data. The HEC-RAS model hydrodynamic input data were used to simulate 52 scenarios covering a broad range of flows and water temperatures with the eggs at risk of hatching ranging from 0 to 93% depending on river conditions. FluEgg simulations depict the highest percentage of eggs at risk of hatching occurs at the lowest discharge and at peak water temperatures. Analysis of these scenarios illustrates how the interactive relation among river length, hydrodynamics, and water temperature influence egg transport and hatching risk. An improved version of FluEgg, which more realistically simulates dispersion and egg development, is presented. Also presented is a graphical user interface that facilitates the use of FluEgg and provides a set of post-processing analysis tools to support management decision-making regarding the prevention and control of Asian carp reproduction in rivers with or without Asian carp populations.

  4. Modelling the impact of prescribed global warming on water resources of headwater catchments of the Irrawaddy River and their implications for Loktak Lake, northeast India

    Science.gov (United States)

    Singh, C. R.; Thompson, J. R.; French, J. R.; Kingston, D. G.; Mackay, A. W.

    2010-05-01

    Climate change is likely to have major implications for wetland ecosystems, which will include altered water level regimes due to modifications in local and catchment hydrology. However, substantial uncertainty exists in the precise impacts of climate change on wetlands due in part due to uncertainty in GCM projections. This paper explores the impacts of climate change upon river discharge within three sub-catchments of Loktak Lake, an internationally important wetland in northeast India. This is achieved by running pattern-scaled GCM output through distributed hydrological models (developed using MIKE SHE) of each sub-catchment. The impacts of climate change upon water levels within Loktak Lake are subsequently investigated using a water balance model. Two groups of climate change scenarios are investigated. Group 1 uses results from seven different GCMs for an increase in global mean temperature of 2 °C, the purported threshold of "dangerous" climate change, whilst Group 2 is based on results from the HadCM3 GCM for increases in global mean temperature between 1 °C and 6 °C. Results from the Group 1 scenarios show varying responses between the three sub-catchments. The majority of scenario-sub-catchment combinations (13 out of 21) indicate increases in discharge which vary from hydropower barrage that impounds the lake and necessitating the release of water for barrage structural stability. Although elevated water levels may permit enhanced abstraction for irrigation and domestic uses, future increases in hydropower generation are limited by existing infrastructure. The higher water levels are likely to exacerbate existing ecological deterioration within the lake as well as enhancing problems of flooding of lakeside communities.

  5. An analysis on the evolvement processes of lake eutrophication and their characteristics of the typical lakes in the middle and lower reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiaoying; LI Shijie

    2006-01-01

    According to the study on the aquatic environment of the typical lakes in the middle and lower reaches of Yangtze River, lake eutrophication is a process in which the lake ecosystem degenerates,resulting in the deterioration of the water quality due to the enrichment of the nutrients. Moreover, the succession of lake ecosystem and change of water quality both couple well with the evolvement of trophic state. Then the conceptual model is mentioned and ten lake states are classified. Based on these,the authors analyzed the eutrophication processes of the typical lakes in the middle and lower reaches of Yangtze River. The large lakes with taking in - sending out water typical of Poyang Lake evolve from State 1 before the 1980s into State 2 after the 1980s,the large and medium lakes typical of Taihu Lake evolve from State 1 -2 in the 1960s into State 8 in the 1980s then into State 9 in the 1990s, the medium and small shallow lakes typical of Honghu Lake evolve from State 1 in the 1960s into State 2 after the 1980s and the small city (suburban) lakes typical of Donghu Lake evolve from State 2 in the 1960s into State 9after the 1970s. Further, the 1980s is the key conversion period of the lakes of various types typical of Poyang Lake, Honghu Lake and Taihu Lake converting into mesotrophic state, the 1990s is that of Taihu Lake into eutrophic state and the 1970s is that of the small city (suburban) lakes typical of Donghu Lake into eutrophic state. The series of nutrient evolvement of different typical lakes are similar, but the processes are not synchronous, which is related to the various human and natural driving mechanisms in lake basins.

  6. CryoSat-2 Altimetry Applications over Rivers and Lakes

    DEFF Research Database (Denmark)

    Jiang, Liguang; Schneider, Raphael; Andersen, Ole Baltazar

    2017-01-01

    pattern and provides new opportunities for hydrologic research. The narrow inter-track distance (7.5 km at the equator) makes it possible to monitor many lakes and rivers and SAR mode provides a finer along-track resolution, higher return power and speckle reduction through multi-looks. However, CryoSat-2...... combined with hydrologic/hydrodynamic models. Except CryoSat-2, all radar altimetry missions have been operated in conventional low resolution mode with a short repeat orbit (35 days or less). CryoSat-2, carrying a Synthetic Aperture Radar (SAR) altimeter, has a 369-day repeat and a drifting ground track...

  7. Stream catalog of the Wood River Lake System

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Information on the red salmon runs to all the major spawning tributaries in the Wood River lake system, Bristol Bay, Alaska from 1946 to 1962 is cataloged in this...

  8. Impact of lake-river connectivity and interflow on the Canadian RCM simulated regional climate and hydrology for Northeast Canada

    Science.gov (United States)

    Huziy, O.; Sushama, L.

    2017-02-01

    Lakes affect regional climate by modulating surface albedo, surface energy, and moisture budgets. This is especially important for regions such as Northeast Canada with approximately 10 % of the landmass covered by lakes, wetlands and rivers. From the regional hydrology perspective, interactions between lakes and rivers are important as streamflow patterns can be significantly modified by lake storage, and similarly lake levels can be modified by streamflows. In this study, using a suite of experiments performed with the fifth generation Canadian Regional Climate Model (CRCM5) driven by the European Centre for Medium range Weather Forecasting ERA40 reanalysis data at the lateral boundaries for the 1979-2010 period, lake-river-atmosphere interactions and their impact on the regional climate/hydrology of north-east Canada are assessed. In these CRCM5 simulations, a one-dimensional lake model represents lakes, while the rivers are modeled using a distributed routing scheme, and one of the simulations includes interflow, i.e. lateral flow of water in the soil layers. Comparison of CRCM5 simulations with and without lakes suggests significant differences in winter/summer precipitation and winter temperature for the study region. CRCM5 simulations performed with and without lake-river interactions suggest improved representation of streamflows when lake storage and routing are taken into account. Adding the interflow process leads to increased streamflows during summer and fall seasons for the majority of the rivers, causing modest changes to land-atmosphere interactions via modified soil moisture. The impact of interflow on streamflow, obtained in this study, is comparable to the impact of lake-atmosphere interactions on streamflows. This study clearly demonstrates the need for realistic representation of lake-river interactions in regional climate models for realistic simulation of regional hydrology, particularly streamflows.

  9. The impact of nitrogen contamination and river modification on a Mississippi River floodplain lake.

    Science.gov (United States)

    Karthic, Indu; Brugam, Richard B; Retzlaff, William; Johnson, Kevin

    2013-10-01

    Anthropogenic nitrogen contamination has increased in ecosystems around the world (frequently termed the "nitrogen cascade"). Coke production for steel manufacturing is often overlooked as a source of nitrogen to natural ecosystems. We examined sediment cores from a Horseshoe Lake, a floodplain lake located just East of St. Louis Missouri (USA) to test whether a coking plant effluent could be traced using stable isotopes of nitrogen and diatom microfossils. The distribution of δ(15)N values in surface sediment samples from the lake shows the highest values near the coking plant effluent. Stable isotopes of nitrogen from 4 sediment cores using a mixing model showed three sources of nitrogen since 1688 CE. The first source (active between 1688 and 1920 CE) had a calculated δ(15)N value ranging between -0.4 and 1.1‰ depending on the core. After 1920 a second source with a δ(15)N ranging between 10.6 and 15.4‰ became active. The change in these sources coincides with the construction of a coking plant on the lake shore. A third source with a value approximately 7.0‰ was present at all times and represents background. The diatom microfossil assemblages present from 1688 CE to the late 1800s are dominated by the planktonic species Aulacoseira granulata and periphytic and benthic genera Gomphonema, Cocconeis, and Lyrella. After the late 1800s the diatom assemblages are dominated by Staurosira species indicating a shift of species from high flow riverine environments to epipelic species from a lake environment. Diatom microfossils seem to track the reduction in flooding due to leveeing of the floodplain and the isolation of the lake from the river. Our results show how stable isotopes of nitrogen can be used to track nitrogen inputs from industrial sources. Diatom changes corresponded with changes in connectivity between the Mississippi River and its floodplain.

  10. Lakes and rivers as microcosms, version 2.0

    Directory of Open Access Journals (Sweden)

    David G. Jenkins

    2013-08-01

    Full Text Available Limnology has been greatly influenced by The Lake as a Microcosm (Forbes, 1887, which described a holistic focus on the internal machinations of singular, island-like aquatic ecosystems. I consider three persistent influences of The Lake as a Microcosm: as an organizing paradigm for the teaching of limnology relative to its practice; the idea that inland waters are like islands, and the replicability of types of inland waters. Based on inspection of recent peer-reviewed literature and 32 limnology texts, we teach limnology according to Forbes but do not practice it in that holistic context. Instead, we practice limnology as aquatic ecology. Based on novel analyses of species-area relationships for 275 inland waters and 392 islands, inland waters are more like continental habitat patches than islands; the island metaphor is poetic but not accurate. Based on a quantitative review of beta diversity (40 data sets representing 10,576 inland waters and 26 data sets representing 1529 terrestrial sites, aquatic systems are no more replicable than are terrestrial systems; a typological approach to limnology is no more justified than it is in terrestrial systems. I conclude that a former distinction between limnology and aquatic ecology no longer applies, and that we should define limnology as the ecology of inland waters. Also, we should not consider lakes and rivers as islands that represent other systems of the same type, but should consider them as open, interactive habitat patches that vary according to their geology and biogeography. I suggest modern limnology operates according to 3 paradigms, which combine to form 3 broad limnological disciplines and establish a basis for a plural, interactive view of lakes and rivers as microcosms. This model of modern limnology may help better connect it to ecology and biogeography and help limnology be even more relevant to science and society.

  11. Numerical groundwater flow modeling of the northern river catchment of the Lake Tana, Upper Blue Basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    Nigussie Ayehu Asrie

    2016-06-01

    Full Text Available The study area is found North Western plateau in the North Gondar zone, Amhara regional state, Ethiopia. Its total surface coverage is 1887km2.The study area boundary was delineated from 90m Shutter Radar Terrain Mapping (SRTM digital elevation model (DEM using Global Mapper 8 software. Based on geologic information of the study area, unconfined subsurface flow condition was considered and simulated using MODFLOW 2000. The model calibration accounts the matching of the 58 observation point with simulated head with a permissible residual head of ±10m. 75% of the difference the observed and measured water level head in the study area is 5m. . The model was calibrated with mean error 0.506, absolute mean error 4.431m and standard deviation 6.083m. Based on the calibration process, the model is very sensitive in decreasing order change in recharge, hydraulic conductivity, and stream bed conductance. The simulated out flow of the model is 205.7Mm3/year which is nearly equal to simulated inflow with difference 2,887.45m3/yr. The base flow simulated discharge Megech River holds 35.8% of the out flow. The river contributed as recharge in to the aquifer that accounts to 15.3% of the inflow. Steady state withdrawal rates were increased by 15%, 35%, 55%, 75% and 100% to study the response of the system in this scenario. From the simulation results, one can observe that the development of a new groundwater sources would not pose appreciable impact in case of 15% and 35% withdrawal the head declines in this case is insignificant relative to the steady state withdrawal rate and the natural discharges were not altered highly. The simulation result indicated that the stream leakage decreased by 7.9% relative to the whole steady state value, but showed 14.9% decrease for Angereb, Keha, and Shinta river segments near the well field area. The water tables decline by 3.6m to18.8m in head observation in the well field area. The steady state simulated recharge was

  12. EFFECT OF SANTA ROSA LAKE ON GROUND WATER FLOW TO THE PECOS RIVER, NEW MEXICO.

    Science.gov (United States)

    Risser, Dennis W.

    1985-01-01

    In 1980, Santa Rosa Dam began impounding water on the Pecos River about 7 miles (11 kilometers) north of Santa Rosa, New Mexico, to provide flood control and storage for irrigation. Santa Rosa Lake has caused changes in the ground water flow system, which may cause changes in the streamflow of the Pecos River that cannot be detected at the present streamflow-gaging stations, which are used to administer water rights along the Pecos River. The effect of the lake on streamflow was investigated using a three-dimensional ground water flow model. These simulations indicated that the net change in ground water flow to the river would be almost zero if the lake were maintained at its flood control pool for 90 days.

  13. Carl L. Estes Lake. Sabine River, Texas. Draft Environmental Statement.

    Science.gov (United States)

    1975-10-01

    to the Gulf of Mexico is Sabine Pass, located at the extreme southwestern end of the lake. 2.15 Sabine River Compact. The Sabine River Compact was...Emory, the Rains County Free Fair has been a popular attraction since the 1930’s. 2 - 31, Quitain has a Dogwood Fiesta which features marked trails

  14. The impact of nitrogen contamination and river modification on a Mississippi River floodplain lake

    Energy Technology Data Exchange (ETDEWEB)

    Karthic, Indu [Box 1099 Environmental Sciences Program, Southern Illinois University, Edwardsville, IL 62026 (United States); Brugam, Richard B., E-mail: rbrugam@siue.edu [Box 1651 Department of Biological Sciences, Southern Illinois University, Edwardsville, IL 62026 (United States); Retzlaff, William [Box 1099 Environmental Sciences Program, Southern Illinois University, Edwardsville, IL 62026 (United States); Johnson, Kevin

    2013-10-01

    Anthropogenic nitrogen contamination has increased in ecosystems around the world (frequently termed the “nitrogen cascade”). Coke production for steel manufacturing is often overlooked as a source of nitrogen to natural ecosystems. We examined sediment cores from a Horseshoe Lake, a floodplain lake located just East of St. Louis Missouri (USA) to test whether a coking plant effluent could be traced using stable isotopes of nitrogen and diatom microfossils. The distribution of δ{sup 15}N values in surface sediment samples from the lake shows the highest values near the coking plant effluent. Stable isotopes of nitrogen from 4 sediment cores using a mixing model showed three sources of nitrogen since 1688 CE. The first source (active between 1688 and 1920 CE) had a calculated δ{sup 15}N value ranging between − 0.4 and 1.1‰ depending on the core. After 1920 a second source with a δ{sup 15}N ranging between 10.6 and 15.4‰ became active. The change in these sources coincides with the construction of a coking plant on the lake shore. A third source with a value approximately 7.0‰ was present at all times and represents background. The diatom microfossil assemblages present from 1688 CE to the late 1800s are dominated by the planktonic species Aulacoseira granulata and periphytic and benthic genera Gomphonema, Cocconeis, and Lyrella. After the late 1800s the diatom assemblages are dominated by Staurosira species indicating a shift of species from high flow riverine environments to epipelic species from a lake environment. Diatom microfossils seem to track the reduction in flooding due to leveeing of the floodplain and the isolation of the lake from the river. Our results show how stable isotopes of nitrogen can be used to track nitrogen inputs from industrial sources. Diatom changes corresponded with changes in connectivity between the Mississippi River and its floodplain. - Highlights: • Effluent from a steel plant increases fixed nitrogen input to a

  15. The initial analysis of the river Ibar temperature downstream of the lake Gazivode

    Directory of Open Access Journals (Sweden)

    Kalaba Dragan V.

    2014-01-01

    Full Text Available As a result of a very limited number of geometric and other input data, the temperature modeling of the river Ibar downstream of the lake Gazivode was started by analyzing one river reach between Pridvorica, secondary dam in the system Gazivode, and the city Kosovska Mitrovica. River reach was selected so that the numerical results can be compared with available measured temperature data. Water quality component of HEC-RAS one-dimensional hydraulic river model was used for temperature calculations. [Projekat Ministarstva nauke Republike Srbije, br. 43007: Studying climate change and its influence on the environment: impacts, adaptation and mitigation

  16. 3D simulation of the influence of internal mixing dynamics on the propagation of river plumes in Lake Constance

    Science.gov (United States)

    Pflugbeil, Thomas; Pöschke, Franziska; Noffke, Anna; Winde, Vera; Wolf, Thomas

    2017-04-01

    Lake Constance is one of most important drinking water resources in southern Germany. Furthermore, the lake and its catchment is a meaningful natural habitat as well as economical and cultural area. In this context, sustainable development and conservation of the lake ecosystem and drinking water quality is of high importance. However, anthropogenic pressures (e.g. waste water, land use, industry in catchment area) on the lake itself and its external inflows are high. The project "SeeZeichen" (ReWaM-project cluster by BMBF, funding number 02WRM1365) is investigating different immission pathways (groundwater, river, superficial inputs) and their impact on the water quality of Lake Constance. The investigation includes the direct inflow areas as well as the lake-wide context. The present simulation study investigates the mixing dynamics of Lake Constance and its impacts on river inflows and vice versa. It considers different seasonal (mixing and stratification periods), hydrological (flood events, average and low discharge) and transport conditions (sediment loads). The simulations are focused on two rivers: The River Alpenrhein delivers about 60 % of water and material input into Lake Constance. The River Schussen was chosen since it is highly anthropogenic influenced. For this purpose, a high-resolution three-dimensional hydrodynamic model of the Lake Constance is set up with Delft3D-Flow model system. The model is calibrated and validated with long term data sets of water levels, discharges and temperatures. The model results will be analysed for residence times of river water within the lake and particle distributions to evaluate potential impacts of river plume water constituents on the general water quality of the lake.

  17. Economic Impacts from Spending by Community Dock Owners at Rough River Lake

    Science.gov (United States)

    2008-01-01

    community dock • Pomme de Terre Lake, community dock • Harry S. Truman Dam and Reservoir, marina • Raystown Lake, marina • Hartwell Lake, private...Rock Lake (Missouri/Arkansas), Rough River Lake (Kentucky), and Pomme de Terre Lake (Missouri). The ERB staff designed the survey, constructed the

  18. Timing and process of river and lake terrace formation in the Kyrgyz Tien Shan

    Science.gov (United States)

    Burgette, Reed J.; Weldon, Ray J.; Abdrakhmatov, Kanatbek Ye.; Ormukov, Cholponbek; Owen, Lewis A.; Thompson, Stephen C.

    2017-03-01

    Well-preserved flights of river and lake terraces traverse an actively deforming rangefront, and form a link between glaciated mountains and a large intermontane lake in the Issyk-Kul basin of the Kyrgyz Tien Shan. We investigated the history and geometry of these lake and river terraces using geologic mapping, surveying, and radiocarbon and terrestrial cosmogenic nuclide dating. A prominent late Pleistocene highstand of the lake occurred over at least the period of 43-25 ka, followed by a period of deep regression and subsequent rise of the lake to the modern sill level in the late Holocene. Major aggradation of the most prominent latest Quaternary river terrace along the Ak-Terek and Barskaun rivers likely started at ∼70-60 ka, coincident to the local last glacial maximum in this region. In contrast to some models of aggradation and incision, the rivers appear to have stayed near the top of the fill for >20 ka, incising subtly below the top of this fill by ∼37 ka, locally. Deep incision likely did not occur until the peak deglaciation in the latest Pleistocene. Older dated terrace surfaces are consistent with one major terrace-forming event per glacial, constant deformation and incision rates, and typical fluvial gradients lower than the modern incising streams. The dating confirms regional terrace correlations for the most prominent late Quaternary terraces, but correlating higher terraces is complicated by spatially varying uplift rates and preferential terrace preservation between basins in the Tien Shan.

  19. RIVER SYSTEM AND DISTURBANCE FACTORS IN THE LAKE TOBA

    Institute of Scientific and Technical Information of China (English)

    Zulkifli Nasution; Mashhor Mansor

    2004-01-01

    Situated at an elevation of 905 m above sea level in the Province of North Sumatra, Lake Toba and its surrounding landscapes are regarded as a natural heritage in a certain extent, as a quoted national treasure. Unfortunately degradation of the land and water resources in the watershed along Lake Toba is taking place at an alarming and totally unacceptable rate. The quality of the lake is partly depended on input the quality of the rivers. When compared to the control area the water quality that influenced by the piggeries are highly polluted. It can be concluded that the Salbe River at the downstream of the piggeries has been polluted and apparently it is a serious problem to the catchment area management. It should be noted that the polluted river would influence the water quality of the Lake Toba. Based on calculation, the permissible BOD5 according to B - river standard is 238 mg/L, it means the river still in B standard but the condition and quality are decreasing continuously. Following the Indonesian health standard the permissible BOD is - 461 mg/L. It means BOD in the river should be reduced 461 mg/L or clean program is needed.

  20. Artificial Post mining lakes - a challenge for the integration in natural hydrography and river basin management

    Science.gov (United States)

    Fleischhammel, Petra; Schoenheinz, Dagmar; Grünewald, Uwe

    2010-05-01

    mesotrophic conditions. The aquatic flora and fauna are limited to a few well adapted species. Therefore, the issue of hydrochemical constitution of the lakes' waters becomes more and more relevant. The prediction of water quality development in post mining lakes is a key requirement to regulate and manage the later hydrochemical conditions. Initially, this prediction was made by individual case studies for single lakes. By means of an iterative research process during the last years, hydrochemical lake models were developed as prediction tools, which allow a complex processing of interconnected post mining lakes and their integration in natural hydrography with respect to quantitative and qualitative evaluation. To counteract the poor water quality of mining lakes, flooding by surface water from neighbouring river basins, e.g. the river Neisse, shall support a quicker and thereby hydrochemically less damaging lake filling. However, this external flooding is only feasible under conditions of high runoff and therefore only as intermitted practice applicable. Additionally, technological measures of water treatment have to be applied to achieve the required effluent quality and to ensure the designated use. Regrettably, these technologies aren't commercially standard up to now and are not sustainable, while flooding or provides a huge amount itself of positive potential for hydrochemical stabilization. The river basin management of the rivers Spree and Schwarze Elster is attended by a common working group of the Federal States of Brandenburg and Berlin as well as the Free State of Saxony. The quantitative distribution of the regionally available water considers the potential use for drinking water supply, process water, …, and the flooding of open-pits. However, due to the formulated rank order, the flooding of the numerous mining open pits in Lusatia is on the last position. To guarantee a reliable flooding and a continuous water supply of the post mining lakes, additional

  1. Lake Michigan lake trout PCB model forecast post audit

    Science.gov (United States)

    Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents th...

  2. Modelling the impact of prescribed global warming on runoff from headwater catchments of the Irrawaddy River and their implications for the water level regime of Loktak Lake, northeast India

    Directory of Open Access Journals (Sweden)

    C. R. Singh

    2010-09-01

    Full Text Available Climate change is likely to have major implications for wetland ecosystems, which will include altered water level regimes due to modifications in local and catchment hydrology. However, substantial uncertainty exists in the precise impacts of climate change on wetlands due in part to uncertainty in GCM projections. This paper explores the impacts of climate change upon river discharge within three sub-catchments of Loktak Lake, an internationally important wetland in northeast India. This is achieved by running pattern-scaled GCM output through distributed hydrological models (developed using MIKE SHE of each sub-catchment. The impacts of climate change upon water levels within Loktak Lake are subsequently investigated using a water balance model. Two groups of climate change scenarios are investigated. Group 1 uses results from seven different GCMs for an increase in global mean temperature of 2 °C, the purported threshold of ''dangerous'' climate change, whilst Group 2 is based on results from the HadCM3 GCM for increases in global mean temperature between 1 °C and 6 °C. Results from the Group 1 scenarios show varying responses between the three sub-catchments. The majority of scenario-sub-catchment combinations (13 out of 21 indicate increases in discharge which vary from <1% to 42% although, in some cases, discharge decreases by as much as 20%. Six of the GCMs suggest overall increases in river flow to Loktak Lake (2–27% whilst the other results in a modest (6% decline. In contrast, the Group 2 scenarios lead to an almost linear increase in total river flow to Loktak Lake with increasing temperature (up to 27% for 6 °C, although two sub-catchments experience reductions in mean discharge for the smallest temperature increases. In all but one Group 1 scenario, and all the Group 2 scenarios, Loktak Lake water levels are higher, regularly reaching the top of a downstream hydropower barrage that impounds the lake and necessitating the

  3. Seismic and electrical work at rivers and lakes of Siberia

    Science.gov (United States)

    Seleznev, V. S.; Soloviev, V. M.; Liseikin, A. V.; Sigonin, P.

    2013-05-01

    In West and East Siberia a great deal of rivers and big lakes are situated. For oil and gas exploration these places hold much promise. It is very difficult to carry out seismic work in these regions, when temperature is fall down below 40 degrees centigrade. It is necessary to pave ways for technical equipment, to organize shooting operations in some cases, that harming ecology of investigated regions. It is well-known, that at seas and big reservoirs seismic works are carried out with use of air guns as sources and floating or ground cables as receivers. There is a special interest to carry out jointly processing and interpretation of seismic survey and electrical data. We should learn how to carry out such researches at rivers, developed a special combined technology on river seismic and electrical works carrying out. Geophysical Survey SB RAS has been carried out seismic and electrical works at rivers and reservoirs of Siberia for more then 20 years. We had to work in conditions, when depth of a reservoir was more then 10 meters or less then 1 meter. It was necessary to work out or adapt some floating equipment, to create air-guns working on light depths ("Malysh", "Sibiryak"), to create new recording equipment (seismic and electrical variants of "Baikal" equipment) for carrying out work in such conditions. There are presented the results of seismic researches, carried out in the Lake Baikal, Lake Teletskoe. For the first time it was determined, that the depth of sedimentary cover under Lake Baikal exceeds 14 km. On demands of government and private companies we carried out river works in Common-depth-point method at such rivers as: Ob, Volga, Enisey, Vakh, Lena, Kirenga, Nizhnya Tunguska. Comparison of results got at river profiles with surface ones, crossing the river, showed in difficult surface conditions (central part of the River Lena, the Nizhnya Tunguska) river seismic sections are better then surface sections. It is connected with the fact, that

  4. Reevaluation of lake trout and lake whitefish bioenergetics models

    Science.gov (United States)

    Madenjian, Charles P.; Pothoven, Steve A.; Kao, Yu-Chun

    2013-01-01

    Using a corrected algorithm for balancing the energy budget, we reevaluated the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush) in the laboratory and for lake whitefish (Coregonus clupeaformis) in the laboratory and in the field. For lake trout, results showed that the bioenergetics model slightly overestimated food consumption by the lake trout when they were fed low and intermediate rations, whereas the model predicted food consumption by lake trout fed ad libitum without any detectable bias. The slight bias in model predictions for lake trout on restricted rations may have been an artifact of the feeding schedule for these fish, and we would therefore recommend application of the Wisconsin lake trout bioenergetics model to lake trout populations in the field without any revisions to the model. Use of the Wisconsin bioenergetics model for coregonids resulted in overestimation of food consumption by lake whitefish both in the laboratory and in the field by between 20 and 30%, on average. This overestimation of food consumption was most likely due to overestimation of respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit to the observed consumption in our laboratory tanks. The adjusted model predicted the consumption in the laboratory and the field without any detectable bias. Until a detailed lake whitefish respiration study can be conducted, we recommend application of our adjusted version of the Wisconsin generalized coregonid bioenergetics model to lake whitefish populations in the field.

  5. The ESA River & Lake System: Current Capabilities and Future Potential

    DEFF Research Database (Denmark)

    Smith, Richard G.; Salloway, Mark; Berry, Philippa A. M.;

    Measuring the earth's river and lake resources using satellite radar altimetry offers a unique global monitoring capability, which complements the detailed measurements made by the steadily decreasing number of in-situ gauges. To exploit this unique remote monitoring capability, a global pilot sc...

  6. Carbon Dioxide and Methane Evasion from Amazonian Rivers and Lakes

    Science.gov (United States)

    Melack, J. M.; Barbosa, P.; Schofield, V.; Amaral, J.; Forsberg, B.; Farjalla, V.

    2013-12-01

    Floodplains, with their mosaic of aquatic habitats, constitute the majority of the wetlands of South America. We report 1) estimates of CH4 and CO2 flux from Amazonian floodplain lakes and rivers during low, rising and high water periods, and 2) identify environmental factors regulating these fluxes. We sampled 10 floodplain lakes, 4 tributaries of Solimões River, 6 stations on the Solimões main stem and 1 station on the Madeira, Negro and Amazonas rivers. Diffusive fluxes were measured with static floating chambers. CH4 fluxes were highly variable, with the majority of the values lower than 5 mmol m-2 d-1. For the lakes, no significant differences among the periods were found. CH4 concentration in the water and water temperature were the two main environmental factors regulating the diffusive flux. Our results highlight the importance of considering both the spatial and temporal scales when estimating CH4 fluxes for a region. CO2 fluxes from water to atmosphere ranged between 327 and -21 mmol m-2 d-1, averaging 58 mmol m-2 d-1. We found higher evasion rates in lakes than in rivers. For both systems the lowest rates were found in low water. pH and dissolved oxygen, phosphorous and organic carbon were the main factors correlated to CO2 evasion from the water bodies.

  7. SIMULATING LAKE PONTCHARTRAIN AND MISSISSIPPI RIVER OUTFLOW AFTER HURRICANE KATRINA

    Science.gov (United States)

    Hurricane Katrina was the direct cause of the flooding of New Orleans in September 2005. Between its passage and the pumping of flood waters back into Lake Pontchartrain and the Mississippi River, the flood waters acquired considerable amounts of contaminants, notably silver, but...

  8. Modelling river dune development

    NARCIS (Netherlands)

    Paarlberg, Andries; Weerts, H.J.T.; Dohmen-Janssen, Catarine M.; Ritsema, I.L; Hulscher, Suzanne J.M.H.; van Os, A.G.; Termes, A.P.P.

    2005-01-01

    Since river dunes influence flow resistance, predictions of dune dimensions are required to make accurate water level predictions. A model approach to simulate developing river dunes is presented. The model is set-up to be appropriate, i.e. as simple as possible, but with sufficient accuracy for

  9. Estimated effects on water quality of Lake Houston from interbasin transfer of water from the Trinity River, Texas

    Science.gov (United States)

    Liscum, Fred; East, Jeffery W.

    2000-01-01

    The City of Houston is considering the transfer of water from the Trinity River to Lake Houston (on the San Jacinto River) to alleviate concerns about adequate water supplies for future water demands. The U.S. Geological Survey, in cooperation with the City of Houston, conducted a study to estimate the effects on the water quality of Lake Houston from the transfer of Trinity River water. A water-quality model, CE–QUAL–W2, was used to simulate six water-quality properties and constituents for scenarios of interbasin transfer of Trinity River water. Three scenarios involved the transferred Trinity River water augmenting streamflow in the East Fork of Lake Houston, and three scenarios involved the transferred water replacing streamflow from the West Fork of the San Jacinto River.The estimated effects on Lake Houston were determined by comparing volume-weighted daily mean water temperature, phosphorus, ammonia nitrogen, nitrite plus nitrate nitrogen, algal biomass, and dissolved oxygen simulated for each of the transfer scenarios to simulations for a base dataset. The effects of the interbasin transfer on Lake Houston do not appear to be detrimental to water temperature, ammonia nitrogen, or dissolved oxygen. Phosphorus and nitrite plus nitrate nitrogen showed fairly large changes when Trinity River water was transferred to replace West Fork San Jacinto River streamflow. Algal biomass showed large decreases when Trinity River water was transferred to augment East Fork Lake Houston streamflow and large increases when Trinity River water was transferred to replace West Fork San Jacinto River streamflow. Regardless of the scenario simulated, the model indicated that light was the limiting factor for algal biomass growth.

  10. Remote sensing study of Maumee River effects of Lake Erie

    Science.gov (United States)

    Svehla, R.; Raquet, C.; Shook, D.; Salzman, J.; Coney, T.; Wachter, D.; Gedney, R.

    1975-01-01

    The effects of river inputs on boundary waters were studied in partial support of the task to assess the significance of river inputs into receiving waters, dispersion of pollutants, and water quality. The effects of the spring runoff of the Maumee River on Lake Erie were assessed by a combination of ship survey and remote sensing techniques. The imagery obtained from a multispectral scanner of the west basin of Lake Erie is discussed: this clearly showed the distribution of particulates throughout the covered area. This synoptic view, in addition to its qualitative value, is very useful in selecting sampling stations for shipboard in situ measurements, and for extrapolating these quantitative results throughout the area of interest.

  11. Water pollution control technology and strategy for river-lake systems: a case study in Gehu Lake and Taige Canal.

    Science.gov (United States)

    Zhang, Yimin; Zhang, Yongchun; Gao, Yuexiang; Zhang, Houhu; Cao, Jianying; Cai, Jinbang; Kong, Xiangji

    2011-07-01

    The Taoge water system is located in the upstream of Taihu Lake basin and is characterized by its multi-connected rivers and lakes. In this paper, current analyses of hydrology, hydrodynamics and water pollution of Gehu Lake and Taige Canal are presented. Several technologies are proposed for pollution prevention and control, and water environmental protection in the Taihu Lake basin. These included water pollution control integration technology for the water systems of Gehu Lake, Taige Canal and Caoqiao River. Additionally, river-lake water quality and quantity regulation technology, ecological restoration technology for polluted and degraded water bodies, and water environmental integration management and optimization strategies were also examined. The main objectives of these strategies are to: (a) improve environmental quality of relative water bodies, prevent pollutants from entering Gehu Lake and Taige Canal, and ensure that the clean water after the pre-treatment through Gehu Lake is not polluted before entering the Taihu Lake through Taige Canal; (b) stably and efficiently intercept and decrease the pollution load entering the lake through enhancing the river outlet ecological system structure function and water self-purifying capacity, and (c) designate Gehu Lake as a regulation system for water quality and water quantity in the Taoge water system and thus guarantee the improvement of the water quality of the inflow into Taihu Lake.

  12. Lake Urmia (Iran): can future socio-ecologically motivated river basin management restore lake water levels in an arid region with extensive agricultural development?

    Science.gov (United States)

    Fazel, Nasim; Berndtsson, Ronny; Bertacchi Uvo, Cintia; Klove, Bjorn; Madani, Kaveh

    2015-04-01

    Lake Urmia, one of the world's largest hyper saline lakes located in northwest of Iran, is a UNESCO Biosphere Reserve and Ramsar site, protected as a national park and, supports invaluable and unique biodiversity and related ecosystem services for the region's 6.5 million inhabitants. Due to increased development of the region's water resources for agriculture and industry and to a certain extent climate change, the lake has started to shrink dramatically since 1995 and now is holding less than 30 percent of its volume. Rapid development in agricultural sector and land-use changes has resulted in immense construction of dams and water diversions in almost all lake feeding rivers, intensifying lake shrinking, increasing salinity and degrading its ecosystem. Recently, lake's cultural and environmental importance and social pressure has raised concerns and brought government attention to the lake restoration plans. Along with poor management, low yield agriculture as the most water consuming activity in the region with, rapid, insufficient development is one of the most influential drivers in the lake desiccation. Part of the lake restoration plans in agricultural sector is to restrict the agricultural areas in the main feeding river basins flowing mostly in the southern part of the lake and decreasing the agricultural water use in this area. This study assess the efficiency and effectiveness of the proposed plans and its influence on the lake level rise and its impacts on economy in the region using a system dynamics model developed for the Lake consist of hydrological and agro-economical sub-systems. The effect of decrease in agricultural area in the region on GDP and region economy was evaluated and compared with released water contribution in lake level rise for a five year simulation period.

  13. Estimation of river and lake heights using cryosat-2 altimetry

    DEFF Research Database (Denmark)

    Villadsen, Heidi; Andersen, Ole Baltazar; Stenseng, Lars

    2013-01-01

    Using a simple threshold retracker on SAR and LRM data from CryoSat-2 it is seen that the SIRAL radar altimeter shows great potential for height estimation over land and inland waters. Differences between heights from the SRTM DEM and the retracked heights were less than 1m for Lake Vättern...... of waveforms over land and inland waters is challenging. Therefore, using a well resolved river and lake mask and focusing on small test regions is recommended until radar altimetry over land and inland waters is fully understood....

  14. 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.

  15. Erosion risk assessment along coastlines, rivers, and lakes

    Science.gov (United States)

    Eidsvig, Unni; Harbitz, Carl B.; Issler, Dieter; Forsberg, Carl Fredrik; Høydal, Øyvind A.; Glimsdal, Sylfest; Frauenfelder, Regula

    2017-04-01

    An effect of the expected climate changes is that densely populated areas will be more exposed to natural hazards. There is a rising concern about geotechnical challenges associated with the transition zone between water and land, in particular with regard to erosion. This needs to be considered as part of the climate adaptation strategies in the society and applies to both coastal settlements and to settlements along rivers. Climate change, as reported by the IPCC, includes global warming, sea level rise as well as more precipitation, both with respect to intensity and frequency. A larger number of cities are expected to be affected by floods and with higher frequency. With large floods, the current speed in rivers and hence their erosion potential increases, leading to scouring along riverbanks, where important transport routes and other infrastructure are often located. The frequency and intensity of storm surges are expected to increase, as well as the risk of coastal erosion. In steep terrain, the likelihood of debris flows increases. The project "Multi-scale Erosion Risk under Climate Change" was initiated to prepare for such challenges as well as local climate adaptation. The project is an internal NGI strategic project funded by the Research Council of Norway for the period 2017 - 2019. The project aims to investigate relevant erosive and mass-flow processes in the coastal zone, along rivers, and in lakes. Further, the knowledge and tools to be developed within the project aim to reduce the risk associated with these processes, through appropriate land-use planning and innovative mitigation measures. The project is thematically subdivided into the following five work packages: WP1: Modelling of erosion processes in rivers, at the coast and in mass movements WP2: Floods, debris flows and sediment mobility in complex topography WP3: Coastal hydrodynamic processes WP4: Monitoring, warning and non-physical mitigation measures WP5: Dissemination and knowledge

  16. Mississippi River Headwaters Lakes in Minnesota. Feasibility Study. Main Report.

    Science.gov (United States)

    1982-09-01

    Surface Water 10 Ground Water 13 Geology and Soils 13 Mining 15 Climate 18 Vegetation 20 Fish 20 Mammals 21 Birds 21 Reptiles and Amphibians 23...primarily for navigation, flood control , hydroelectric power, water supply, recreation, and fish and wildlife enhancement. The six controlled lakes...quality control , fish and wildlife , recreation, and other related areas. The resolution follows: "Resolved by the Committee on Rivers and Harbors of the

  17. Modelling the impact of prescribed global warming on runoff from headwater catchments of the Irrawaddy River and their implications for the water level regime of Loktak Lake, northeast India

    Science.gov (United States)

    Singh, C. R.; Thompson, J. R.; French, J. R.; Kingston, D. G.; Mackay, A. W.

    2010-09-01

    Climate change is likely to have major implications for wetland ecosystems, which will include altered water level regimes due to modifications in local and catchment hydrology. However, substantial uncertainty exists in the precise impacts of climate change on wetlands due in part to uncertainty in GCM projections. This paper explores the impacts of climate change upon river discharge within three sub-catchments of Loktak Lake, an internationally important wetland in northeast India. This is achieved by running pattern-scaled GCM output through distributed hydrological models (developed using MIKE SHE) of each sub-catchment. The impacts of climate change upon water levels within Loktak Lake are subsequently investigated using a water balance model. Two groups of climate change scenarios are investigated. Group 1 uses results from seven different GCMs for an increase in global mean temperature of 2 °C, the purported threshold of ''dangerous'' climate change, whilst Group 2 is based on results from the HadCM3 GCM for increases in global mean temperature between 1 °C and 6 °C. Results from the Group 1 scenarios show varying responses between the three sub-catchments. The majority of scenario-sub-catchment combinations (13 out of 21) indicate increases in discharge which vary from hydropower barrage that impounds the lake and necessitating the release of water for barrage structural stability. Although elevated water levels may permit enhanced abstraction for irrigation and domestic uses, future increases in hydropower generation are limited by existing infrastructure. The higher water levels are likely to exacerbate existing ecological deterioration within the lake as well as enhancing problems of flooding of lakeside communities.

  18. Annual cycle in lakes and rivers from CryoSat-2 altimetry — The Brahmaputra river

    DEFF Research Database (Denmark)

    Villadsen, Heidi; Andersen, Ole Baltazar; Stenseng, Lars

    2014-01-01

    A key concern of the CryoSat-2 orbit has been its long repeat period of 369 days, which is usually undesirable for river and lake monitoring. However, the results of this study show that CryoSat-2 data can indeed be used for such monitoring by utilizing the high spatial coverage and the sub......-cycle period of 30 days. The performance of CryoSat-2/SIRAL altimetry for river level monitoring is investigated by studying river levels retrieved from Ganges and Brahmaputra. An evaluation of CryoSat-2 river levels from LRM, SAR and SARIn data is performed by comparing with Envisat data from the period...... data to continue river level archives from satellite radar altimetry....

  19. Glacial lakes in the Horgos river basin and their outbreak risk assessment

    Directory of Open Access Journals (Sweden)

    A. P. Medeu

    2013-01-01

    Full Text Available The river Khorgos (in Kazakhstan – Korgas is a boundary river between Kazakhstan and China. Its basin is located in the central part of southern slope of Dzhungarskiy (Zhetysu Alatau range. According to agreement between Kazakhstan and China at the boundary transition of Khorgos in the floodplain of the river Khorgos the large Center of Frontier Cooperation is erected. Estimation of safety of the mentioned object including connection with possible glacial lakes outbursts has the importance of political-economical value. Nowadays development of glacial lakes in the overhead part of Khorgos river basin has reached apogee. As a roof we can mention the maximum of total glacial lakes area (1,7 million m² in 41 lakes and emptied kettles of former glacial lakes. Six lakes reached highly dangerous outburst stage: the volume of lakes reached some million m³, maximum depth up to 30–40 m. Focal ground filtration of the water from lakes takes place. Development of glacial lakes in Khorgos river basin will continue, and these lakes give and will give real danger for the Center of Frontier Cooperation in case of outburst of naturally dammed lake Kazankol with the similar mechanism of Issyk lake outburst, occurred in 1963 in ZailijskiyAlatau (Ile Alatau.

  20. Long Valley Caldera Lake and reincision of Owens River Gorge

    Science.gov (United States)

    Hildreth, Wes; Fierstein, Judy

    2016-12-16

    Owens River Gorge, today rimmed exclusively in 767-ka Bishop Tuff, was first cut during the Neogene through a ridge of Triassic granodiorite to a depth as great as its present-day floor and was then filled to its rim by a small basaltic shield at 3.3 Ma. The gorge-filling basalt, 200 m thick, blocked a 5-km-long reach of the upper gorge, diverting the Owens River southward around the shield into Rock Creek where another 200-m-deep gorge was cut through the same basement ridge. Much later, during Marine Isotope Stage (MIS) 22 (~900–866 ka), a piedmont glacier buried the diversion and deposited a thick sheet of Sherwin Till atop the basalt on both sides of the original gorge, showing that the basalt-filled reach had not, by then, been reexcavated. At 767 ka, eruption of the Bishop Tuff blanketed the landscape with welded ignimbrite, deeply covering the till, basalt, and granodiorite and completely filling all additional reaches of both Rock Creek canyon and Owens River Gorge. The ignimbrite rests directly on the basalt and till along the walls of Owens Gorge, but nowhere was it inset against either, showing that the basalt-blocked reach had still not been reexcavated. Subsidence of Long Valley Caldera at 767 ka produced a steep-walled depression at least 700 m deeper than the precaldera floor of Owens Gorge, which was beheaded at the caldera’s southeast rim. Caldera collapse reoriented proximal drainages that had formerly joined east-flowing Owens River, abruptly reversing flow westward into the caldera. It took 600,000 years of sedimentation in the 26-km-long, usually shallow, caldera lake to fill the deep basin and raise lake level to its threshold for overflow. Not until then did reestablishment of Owens River Gorge begin, by incision of the gorge-filling ignimbrite.

  1. Assessment of climate and land use changes impacts on the rivers inflow to the Lake Baikal

    Science.gov (United States)

    Kurovskaia, Victoriia; Semenova, Olga; Vinogradova, Tatyana

    2016-04-01

    Baikal is the deepest lake in the world and one of the biggest reservoirs of fresh water. The aim of this research was to analyze the long-term variability of characteristics of river inflow to the Lake using the historical data and project possible changes in the face of non-stationary climate and land use based on hydrological modelling. The basin of the Lake Baikal has area about 545 000 km2, half of which is situated in Russia. It is characterized by different climate and landscape conditions with annual flow depth varying from 30 to more than 600 mm. Nowadays active development and use of natural resources as well as climate changes have a strong impact on the regime of rivers inflow to the Lake. The watersheds response caused by environmental non-stationarity can be variable and unpredictable. Therefore adequate hydrological models with robust parametrization are required for future projections. This study consisted of two parts. Initially we compiled the database of daily runoff data for about 50 gauges in the basin of the Baikal Lake with continuous period of observations 30-50 years. The data was used to assess the characteristics of river inflow to the Lake for the historical period and estimate observed changes due to current climate change. For the development of future projections we have chosen several small and middle-size representative watersheds in different parts of the Lake basin with area from 151 to 7800 km2 and various types of hydrological regime. The data base for modelling was developed which included the information about landscapes, soils, dominating hydrological processes. The hydrological model parameters for different dominant landscapes were estimated based on that information. We applied distributed process-based hydrological model Hydrograph developed in State Hydrological Institute, Russia (Vinogradov et al., 2011; Semenova et al., 2013). It describes all essential processes of land hydrological cycle including detailed algorithm

  2. Life history of the spottail shiner (Notropis hudsonius) in southeastern Lake Michigan, the Kalamazoo River, and western Lake Erie

    Science.gov (United States)

    Wells, LaRue; House, Robert

    1974-01-01

    In southeastern Lake Michigan spottail shiners in samples ranged from ages 0 to V, but most were in age groups I-IV. In the Kalamazoo River (a tributary of southeastern Lake Michigan) age group II was commonest in the catches, and no fish older than age IV were sampled. In western Lake Erie, most shiners were in age groups 0-II, and none were older than age IV. Mortality of males was much higher than that of females after age II in Lake Michigan and after age I in Lake Erie. Growth of spottail shiners was fastest in western Lake Erie (125 mm at the end of the third year, sexes combined) and slowest (77 mm) in the Kalamazoo River; in all three waters growth declined rapidly after the first year. Females grew faster than males.

  3. Moraine-dammed glacial lake changes during the recent 40 years in the Poiqu River Basin, Himalayas

    Institute of Scientific and Technical Information of China (English)

    XiuJuan Zhang; ShiYin Liu; Li Liu

    2015-01-01

    Glacier retreat is not only a symbol of temperature and precipitation change, but a dominating factor of glacial lake changes in alpine regions, which are of wide concern for high risk of potential outburst floods. Of all types of glacial lakes, moraine-dammed lakes may be the most dangerous to local residents in mountain regions. Thus, we monitored the dy-namics of 12 moraine-dammed glacial lakes from 1974 to 2014 in the Poiqu River Basin of central west Himalayas, as well as their associated glaciers with a combination of remote sensing, topographic maps and digital elevation models (DEMs). Our results indicate that all monitored moraine-dammed glacial lakes have expanded by 7.46 km2 in total while the glaciers retreated by a total of 15.29 km2 correspondingly. Meteorological analysis indicates a warming and drying trend in the Nyalam region from 1974 to 2014, which accelerated glacier retreat and then augmented the supply of moraine-dammed glacial lakes from glacier melt. Lake volume and water depth changed from 1974 to 2014 which indicates that lakes Kangxico, Galongco, and Youmojanco have a high potential for outburst floods and in urgent need for continuous moni-toring or artificial excavation to release water due to the quick increase in water depths and storage capacities. Lakes Jialongco and Cirenmaco, with outburst floods in 1981 and 2002, have a high potential risk for outburst floods because of rapid lake growth and steep slope gradients surrounding them.

  4. 46 CFR 401.405 - Basic rates and charges on the St. Lawrence River and Lake Ontario.

    Science.gov (United States)

    2010-10-01

    ... Lake Ontario. 401.405 Section 401.405 Shipping COAST GUARD (GREAT LAKES PILOTAGE), DEPARTMENT OF... § 401.405 Basic rates and charges on the St. Lawrence River and Lake Ontario. Except as provided in.... registered pilots in the St. Lawrence River and Lake Ontario. (a) Area 1 (Designated Waters): Service...

  5. Cryosat-2 and Sentinel-3 tropospheric corrections: their evaluation over rivers and lakes

    Science.gov (United States)

    Fernandes, Joana; Lázaro, Clara; Vieira, Telmo; Restano, Marco; Ambrózio, Américo; Benveniste, Jérôme

    2017-04-01

    In the scope of the Sentinel-3 Hydrologic Altimetry PrototypE (SHAPE) project, errors that presently affect the tropospheric corrections i.e. dry and wet tropospheric corrections (DTC and WTC, respectively) given in satellite altimetry products are evaluated over inland water regions. These errors arise because both corrections, function of altitude, are usually computed with respect to an incorrect altitude reference. Several regions of interest (ROI) where CryoSat-2 (CS-2) is operating in SAR/SAR-In modes were selected for this evaluation. In this study, results for Danube River, Amazon Basin, Vanern and Titicaca lakes, and Caspian Sea, using Level 1B CS-2 data, are shown. DTC and WTC have been compared to those derived from ECMWF Operational model and computed at different altitude references: i) ECMWF orography; ii) ACE2 (Altimeter Corrected Elevations 2) and GWD-LR (Global Width Database for Large Rivers) global digital elevation models; iii) mean lake level, derived from Envisat mission data, or river profile derived in the scope of SHAPE project by AlongTrack (ATK) using Jason-2 data. Whenever GNSS data are available in the ROI, a GNSS-derived WTC was also generated and used for comparison. Overall, results show that the tropospheric corrections present in CS-2 L1B products are provided at the level of ECMWF orography, which can depart from the mean lake level or river profile by hundreds of metres. Therefore, the use of the model orography originates errors in the corrections. To mitigate these errors, both DTC and WTC should be provided at the mean river profile/lake level. For example, for the Caspian Sea with a mean level of -27 m, the tropospheric corrections provided in CS-2 products were computed at mean sea level (zero level), leading therefore to a systematic error in the corrections. In case a mean lake level is not available, it can be easily determined from satellite altimetry. In the absence of a mean river profile, both mentioned DEM

  6. Geology and geomorphology of Bear Lake Valley and upper Bear River, Utah and Idaho

    Science.gov (United States)

    Reheis, M.C.; Laabs, B.J.C.; Kaufman, D.S.

    2009-01-01

    Bear Lake, on the Idaho-Utah border, lies in a fault-bounded valley through which the Bear River flows en route to the Great Salt Lake. Surficial deposits in the Bear Lake drainage basin provide a geologic context for interpretation of cores from Bear Lake deposits. In addition to groundwater discharge, Bear Lake received water and sediment from its own small drainage basin and sometimes from the Bear River and its glaciated headwaters. The lake basin interacts with the river in complex ways that are modulated by climatically induced lake-level changes, by the distribution of active Quaternary faults, and by the migration of the river across its fluvial fan north of the present lake. The upper Bear River flows northward for ???150 km from its headwaters in the northwestern Uinta Mountains, generally following the strike of regional Laramide and late Cenozoic structures. These structures likely also control the flow paths of groundwater that feeds Bear Lake, and groundwater-fed streams are the largest source of water when the lake is isolated from the Bear River. The present configuration of the Bear River with respect to Bear Lake Valley may not have been established until the late Pliocene. The absence of Uinta Range-derived quartzites in fluvial gravel on the crest of the Bear Lake Plateau east of Bear Lake suggests that the present headwaters were not part of the drainage basin in the late Tertiary. Newly mapped glacial deposits in the Bear River Range west of Bear Lake indicate several advances of valley glaciers that were probably coeval with glaciations in the Uinta Mountains. Much of the meltwater from these glaciers may have reached Bear Lake via groundwater pathways through infiltration in the karst terrain of the Bear River Range. At times during the Pleistocene, the Bear River flowed into Bear Lake and water level rose to the valley threshold at Nounan narrows. This threshold has been modified by aggradation, downcutting, and tectonics. Maximum lake

  7. Movement and Harvest of Fish in Lake Saint Clair, Saint Clair River, and Detroit River

    Science.gov (United States)

    1985-01-01

    spring and summer were much more important in Lake St. Clair. The increased availability (net catchability ) of walleyes in the two rivers during fall...in any gear is often expressed as a linear function of the catchability in that gear, multiplied by fishing effort and fish abundance. This...more catchable in nets. Tagged perch moved from net Stations 2 and 3 upstream to be netted again at Station 1, which was more movement between net

  8. Maintaining healthy rivers and lakes through water diversion from Yangtze River to Taihu lake in Taihu Basin

    Directory of Open Access Journals (Sweden)

    Hao-yun WU

    2008-09-01

    Full Text Available On the basis of the Taihu water resources assessment, an analysis of the importance and rationality of the water diversion from the Yangtze River to Taihu Lake in solving the water problem and establishing a harmonious eco-environment in the Taihu Basin is performed. The water quantity and water quality conjunctive dispatching decision-making support system, which ensures flood control, water supply and eco-aimed dispatching, is built by combining the water diversion with flood control dispatching and strengthening water resources monitoring and forecasting. With the practice and effect assessment, measures such as setting the integrated basin management format, further developing water diversion and improving the hydraulic engineering projects system and water monitoring system are proposed in order to maintain healthy rivers and guarantee the development of the economy and society in the Taihu Basin.

  9. Maintaining healthy rivers and lakes through water diversion from Yangtze River to Taihu Lake in Taihu Basin

    Institute of Scientific and Technical Information of China (English)

    Wu Haoyun; Hu Yan

    2008-01-01

    On the basis of the Taihu water resources assessment, an analysis of the importance and rationality of the water diversion from the Yangtze River to Taihu Lake in solving the water problem and establishing a harmonious eco-environment in the Taihu Basin is performed. The water quantity and watcr quality conjunctive dispatching decision-making support system, which ensures flood control, water supply and eco-aimed dispatching, is built by combining the water diversion with flood control dispatching and strengthening water resources monitoring and forecasting. With the practice and effect assessment, measures such as setting the integrated basin management format, further developing water diversion and improving the hydraulic engineering projects system and water monitoring system are proposed in order to maintain healthy rivers and guarantee the development of the economy and society in the Taihu Basin.

  10. Impacts of the Two Biggest Lakes on Local Temperature and Precipitation in the Yellow River Source Region of the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Lijuan Wen

    2015-01-01

    Full Text Available The Tibetan Plateau harbors thousands of lakes; however few studies focus on impacts of lakes on local climate in the region. To investigate and quantify impacts of the two biggest lakes (Ngoring Lake and Gyaring Lake of the Yellow River source region in the Tibetan Plateau on local climate, two simulations (with and without the two large lakes from May 2010 to July 2011 are performed and analyzed using the WRF-CLM model (the weather research and forecasting model coupled with the community land model. Differences between simulated results show that the WRF-CLM model could provide realistic reproduction of surface observations and has better simulation after considering lakes. Lakes mostly reduce the maximum temperature all year round and increase the minimum temperature except in March due to the large heat capacity that makes lakes absorb (release more energy for the same temperature change compared to land. Lakes increase precipitation over the lake area and in the nearby region, mostly during 02–14 BT (Beijing Time of July to October when the warm lake surface induces the low level horizontal convergence and updraft over lake and provides energy and vapor to benefit the development of the convection for precipitation.

  11. SIMULATION OF FRESHWATER PLUME FROM LAKE PONTCHARTRAIN AND THE MISSISSIPPI RIVER IN THE WAKE OF HURRICANE KATRINA

    Science.gov (United States)

    In the spirit of a post-Katrina response, a three-dimensional hydrodynamic model was set up and applied to the hurricane Katrina affected region of Mississippi River delta, Lake Pontchartran, and the Gulf of Mexico coastline near New Orleans. Following Katrina, there was concern ...

  12. Tracing of the Rhône River within Lake Geneva using stable isotope composition of water

    Science.gov (United States)

    Cotte, Gabriel; Vennemann, Torsten

    2017-04-01

    Determining the hydrodynamics of lake water is essential for a better understanding of nutrient transport but also of the distribution of potential pollutants through water reservoirs. The objective of this study is to understand the mixing of Rhône River water within Lake Geneva. During summer and autumn, when the lake thermally well stratified, the Rhône River water can potentially flow more or less directly towards and finally out of the "Petit Lac" (small lake basin close to Geneva) more than 55 km from its mouth. During winter, when stratification is weakened, the water from the Rhône River mixes more diffusively with the water of Lake Geneva. The aim of this study is to determine the path of the Rhône River through the lake more precisely and identify the thermal and meteorologic conditions favourable for different types of flows as suggested by physical circulation models of the Rhône River interflows. Waters are sampled from different North-South transects across the lake. Bathymetric profiles are measured for temperature, pH, conductivity and oxygen concentrations. In addition, the H- and O-isotope compositions of water, the C-isotope composition of dissolved inorganic carbon and the major ions are analysed. Sampling campaigns are carried out every two months to study the hydrodynamics of the lake at varying thermal conditions. The isotopic composition of water was already proven to be a powerful tool to trace the Rhône River interflow within the lake (Halder et al., 2013) but the details of this interflow remain debatable. It is the aim of the present study to use the isotopic tracer method in much more detailed cross-sections as a tool to both test and verify interflow models based on wind patterns and thermal dispersion of the waters. The chosen cross-sections, to be sampled regularly and "event-based", that is after extended periods of similar meteorological conditions, should allow for more precise estimates of the path of the Rhône water

  13. Prevention of Polluting Rivers and Lakes from Ships

    Directory of Open Access Journals (Sweden)

    Natalija Jolić

    2005-09-01

    Full Text Available Traffic on rivers and lakes in Europe has been ve1y well developed.The reason for this is the transport cost, relative speedand good connectivity of major European cities by rivers andcanals. In Croatia, this transport mode is lagging behind therest of Europe. Croatia is located at an interesting section of theriver transversal, but due to several reasons, river navigation inCroatia has not been developed to any major extent. As operatingriver ships the most frequent types are: towboats, pushboatsand self-propelled ships. The installed diesel engines, propulsionand auxiliary engines run at high power. Proportional tothe increase in the power of installed engines is also the increasein the volume of waste produced by the engines. Also, the olderthe engine, the greater volume of waste it produces. Ships mayalso cause pollution by wastewaters and garbage. This pollutionthreat grows with the greater number of people on boardand the age of the ship. In order to minimize these possibilitiesof pollution, it is necesswy to control all the time the properfunctioning of the ships, train the staff and construct receptionfacilities on land.

  14. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital aquifer boundaries for the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in...

  15. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital water-level elevation contours for the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake...

  16. Digital data sets that describe aquifer characteristics of the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake Overholser in central Oklahoma

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set consists of digital polygons of a constant recharge value for the alluvial and terrace deposits along the North Canadian River from Canton Lake to Lake...

  17. Evaluation of a lake whitefish bioenergetics model

    Science.gov (United States)

    Madenjian, Charles P.; O'Connor, Daniel V.; Pothoven, Steven A.; Schneeberger, Philip J.; Rediske, Richard R.; O'Keefe, James P.; Bergstedt, Roger A.; Argyle, Ray L.; Brandt, Stephen B.

    2006-01-01

    We evaluated the Wisconsin bioenergetics model for lake whitefish Coregonus clupeaformis in the laboratory and in the field. For the laboratory evaluation, lake whitefish were fed rainbow smelt Osmerus mordax in four laboratory tanks during a 133-d experiment. Based on a comparison of bioenergetics model predictions of lake whitefish food consumption and growth with observed consumption and growth, we concluded that the bioenergetics model furnished significantly biased estimates of both food consumption and growth. On average, the model overestimated consumption by 61% and underestimated growth by 16%. The source of the bias was probably an overestimation of the respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit of the model to the observed consumption and growth in our laboratory tanks. Based on the adjusted model, predictions of food consumption over the 133-d period fell within 5% of observed consumption in three of the four tanks and within 9% of observed consumption in the remaining tank. We used polychlorinated biphenyls (PCBs) as a tracer to evaluate model performance in the field. Based on our laboratory experiment, the efficiency with which lake whitefish retained PCBs from their food (I?) was estimated at 0.45. We applied the bioenergetics model to Lake Michigan lake whitefish and then used PCB determinations of both lake whitefish and their prey from Lake Michigan to estimate p in the field. Application of the original model to Lake Michigan lake whitefish yielded a field estimate of 0.28, implying that the original formulation of the model overestimated consumption in Lake Michigan by 61%. Application of the bioenergetics model with the adjusted respiration component resulted in a field I? estimate of 0.56, implying that this revised model underestimated consumption by 20%.

  18. Red Lake and Clearwater Rivers, Red Lake County, Minnesota. Reconnaissance Report for Red Lake and Clearwater Rivers

    Science.gov (United States)

    1991-08-01

    2,000 acres, are associated (mainly) with smaller lakes in the subbasin, such as Blackduck, Maple, Julia , Pine and Clearwater. Also, many sumnier homes...flooding fot reproduction. In addition, channel modification could lead to increased wetland drainage. I-creasing the chanel depth or cross section

  19. (210)Pb and compositional data of sediments from Rondonian lakes, Madeira River basin, Brazil.

    Science.gov (United States)

    Bonotto, Daniel Marcos; Vergotti, Marcelo

    2015-05-01

    Gold exploration has been intensive in Brazilian Amazon over the last 40 years, where the use of mercury as an amalgam has caused abnormal Hg concentrations in water bodies. Special attention has been directed to Madeira River due to fact it is a major tributary of Amazon River and that since 1986, gold exploration has been officially permitted along a 350km sector of the river. The (21)(0)Pb method has been used to date sediments taken from nine lakes situated in Madeira River basin, Rondônia State, and to verify where anthropogenic Hg might exist due to gold exploitation in Madeira River. Activity profiles of excess (21)(0)Pb determined in the sediment cores provided a means to evaluate the sedimentation rates using a Constant Flux: Constant Sedimentation (CF:CS) and Constant Rate of Supply (CRS) of unsupported/excess (21)(0)Pb models. A significant relationship was found between the CF:CS sedimentation rates and the mean values of the CRS sedimentation rates (Pearson correlation coefficient r=0.59). Chemical data were also determined in the sediments for identifying possible relationships with Hg occurring in the area. Significant values were found in statistical correlation tests realized among the Hg, major oxides and Total Organic Carbon (TOC) content in the sediments. The TOC increased in the sediment cores accompanied by a loss on ignition (LOI) increment, whereas silica decreased following a specific surface area raising associated to the TOC increase. The CRS model always provided ages within the permitted range of the (21)(0)Pb-method in the studied lakes, whereas the CF:CS model predicted two values above 140 years. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Distribution of Polychlorinated Biphenyls in Lake Shkoder, River Buna and Velipoja Coast Surface Water

    OpenAIRE

    , A. Neziri

    2012-01-01

    Lake Shkodra is the largest lake in the Balkans region. Its surface is 368 km2, from which 149 km2 are included in Albanian territory and the other part belongs to Montenegro.The Buna is a short 44 km river that originates from lake Shkodra and meanders its way to the Adriatic sea. Velipoja coast lies along the Adriatic coastline in the North – West of Albania, near Buna River, which is the only navigable river in Albania.. PCBs are among the most widely known class of persistent organic poll...

  1. Historical Trends in Lake and River Ice Cover in Norway : signs of a changing climate

    OpenAIRE

    Solvang, Tord

    2013-01-01

    Recent studies have shown that the duration of seasonal ice cover on lakes and rivers over the Northern Hemisphere has declined over the 19th and 20th Centuries, mainly as a consequence of rising temperatures. However, lake and river ice trends have not been well documented in Norway. Quality control and homogeneity testing were performed on ice cover data from 48 Norwegian lake and river sites with long records. A total of 142 individual records of ice phenology (freeze-up, break-up and ice ...

  2. Comparison of biogenic methane emissions from unmanaged estuaries, lakes, oceans, rivers and wetlands

    Science.gov (United States)

    Ortiz-Llorente, M. J.; Alvarez-Cobelas, M.

    2012-11-01

    factors is low worldwide. This precludes the use of these variables to develop models to predict emissions at regional scales or wider, despite the many attempts made in the past. This makes local assessments of emissions essential, particularly in warm, temperate and tropical areas of the world. Future research aiming to shed light on CH4 fluxes from estuaries, lakes, oceans, rivers and wetlands must: 1) produce more detailed data on controlling factors; 2) increase efforts to fully characterize spatial and temporal heterogeneity; 3) combine bottom-up (measurements) and top-down (modelling) approaches.

  3. River and Reservoir Operations Model, Truckee River basin, California and Nevada, 1998

    Science.gov (United States)

    Berris, Steven N.; Hess, Glen W.; Bohman, Larry R.

    2001-01-01

    The demand for all uses of water in the Truckee River Basin, California and Nevada, commonly is greater than can be supplied. Storage reservoirs in the system have a maximum effective total capacity equivalent to less than two years of average river flows, so longer-term droughts can result in substantial water-supply shortages for irrigation and municipal users and may stress fish and wildlife ecosystems. Title II of Public Law (P.L.) 101-618, the Truckee?Carson?Pyramid Lake Water Rights Settlement Act of 1990, provides a foundation for negotiating and developing operating criteria, known as the Truckee River Operating Agreement (TROA), to balance interstate and interbasin allocation of water rights among the many interests competing for water from the Truckee River. In addition to TROA, the Truckee River Water Quality Settlement Agreement (WQSA), signed in 1996, provides for acquisition of water rights to resolve water-quality problems during low flows along the Truckee River in Nevada. Efficient execution of many of the planning, management, or environmental assessment requirements of TROA and WQSA will require detailed water-resources data coupled with sound analytical tools. Analytical modeling tools constructed and evaluated with such data could help assess effects of alternative operational scenarios related to reservoir and river operations, water-rights transfers, and changes in irrigation practices. The Truckee?Carson Program of the U.S. Geological Survey, to support U.S. Department of the Interior implementation of P.L. 101-618, is developing a modeling system to support efficient water-resources planning, management, and allocation. The daily operations model documented herein is a part of the modeling system that includes a database management program, a graphical user interface program, and a program with modules that simulate river/reservoir operations and a variety of hydrologic processes. The operations module is capable of simulating lake

  4. Possible changes in ground-water flow to the Pecos River caused by Santa Rosa Lake, Guadalupe County, New Mexico

    Science.gov (United States)

    Risser, D.W.

    1987-01-01

    In 1980 Santa Rosa Dam began impounding water on the Pecos River about 7 miles north of Santa Rosa, New Mexico, to provide flood control, sediment control, and storage for irrigation. Santa Rosa Lake has caused changes in the groundwater flow system, which may cause changes in the streamflow of the Pecos River that cannot be detected at the present streamflow gaging stations. Data collected at these stations are used to measure the amount of water available for downstream users. A three-dimensional groundwater flow model for a 950 sq mi area between Anton Chico and Puerto de Luna was used to simulate the effects of Santa Rosa Lake on groundwater flow to a gaining reach of the Pecos River for lake levels of 4,675, 4,715, 4,725, 4,750, 4,776, and 4,797 feet above sea level and durations of impoundment of 30, 90, 182, and 365 days for all levels except 4 ,797 feet. These simulations indicated that streamflow in the Pecos River could increase by as much as 2 cu ft/sec between the dam and Puerto de Luna if the lake level were maintained at 4 ,797 feet for 90 days or 4,776 feet for 1 year. About 90% of this increased streamflow would occur < 0.5 mi downstream from the dam, some of which would be measured at the streamflow gaging station located 0.2 mile downstream from the dam. Simulations also indicated that the lake will affect groundwater flow such that inflow to the study area may be decreased by as much as 1.9 cu ft/sec. This water may leave the Pecos River drainage basin or be diverted back to the Pecos River downstream from the gaging station near Puerto de Luna. In either case, this quantity represents a net loss of water upstream from Puerto de Luna. Most simulations indicated that the decrease in groundwater flow into the study area would be of about the same quantity as the simulated increase in streamflow downstream from the dam. Therefore, the net effect of the lake on the flow of the Pecos River in the study area appears to be negligible. Model simulations

  5. Anomalies of larval and juvenile shortnose and lost river suckers in upper Klamath Lake, Oregon

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Larval and juvenile shortnose (Chasmistes brevirostris) and Lost River (Deltistes luxatus) suckers from Upper Klamath Lake, OR, were examined to determine anomaly...

  6. Floral Diversity in the Wetlands of Apete River, Eleyele Lake and ...

    African Journals Online (AJOL)

    Floral Diversity in the Wetlands of Apete River, Eleyele Lake and Oba Dam in Ibadan, ... road construction and agricultural activities, but the floristic compositions of these ... A comparative assessment study of the floral of three wetlands in a ...

  7. DNR 100K Lakes and Rivers - Fisheries Experimental and Special Regulations

    Data.gov (United States)

    Minnesota Department of Natural Resources — This layer represents lakes and rivers having experimental or special regulations for fishing. The existing regulations for the current fishing season are shown....

  8. Clumped isotope paleothermometry of the Mio-Pliocene freshwater Lake Mohave. Lower ancestral Colorado River, USA

    Science.gov (United States)

    Lang, K. A.; Huntington, K. W.

    2015-12-01

    The fluvio-lacustrine deposits of the Bouse Formation are an archive of ancestral Colorado River integration in the Late Miocene and Early Pliocene. In Mohave Valley along the California-Arizona-Nevada border, exposures of the Bouse Formation are observed ~400 m above the modern river elevation, which has been interpreted as evidence of tectonic uplift following a regionally extensive marine incursion and integration of the ancestral Colorado River by capture. However, recent investigations instead favor a "top-down" process of river integration by sequential infilling of freshwater lakes that does not require subsequent tectonic uplift. Accurate interpretation of the Bouse Formation's depositional environment is needed to test these models and ultimately, constrain the timing and mechanism of southwestern Colorado Plateau uplift. To further constrain interpretations of depositional environment, we present new clumped isotope analyses with major and trace element geochemistry and scanning electron microscopy of carbonate samples from the Bouse Formation in Mohave Valley. Here the Bouse Formation contains three distinct facies: basal marl and limestone overlain by thick beds of calcareous claystone interbedded with siltstone and sandstone and locally overlain by tufa. Bulk geochemistry of all facies is consistent with a similar freshwater source yet each facies is isotopically distinct, potentially indicating a strong influence of facies-specific fractionation processes. Carbonate formation temperatures measured in tufa samples are variable, suggesting multiple generations of calcite precipitation. Formation temperatures from basal marl and claystone samples are generally consistent with near-surface lake temperatures, broadly supporting a lacustrine depositional environment and "top-down" process of ancestral Colorado River integration. More broadly, our results quantify the variability in carbonate formation temperatures with different lacustrine facies and

  9. Changes in Glaciers and Glacial Lakes and the Identification of Dangerous Glacial Lakes in the Pumqu River Basin, Xizang (Tibet)

    OpenAIRE

    Tao Che; Lin Xiao; Yuei-An Liou

    2014-01-01

    Latest satellite images have been utilized to update the inventories of glaciers and glacial lakes in the Pumqu river basin, Xizang (Tibet), in the study. Compared to the inventories in 1970s, the areas of glaciers are reduced by 19.05% while the areas of glacial lakes are increased by 26.76%. The magnitudes of glacier retreat rate and glacial lake increase rate during the period of 2001–2013 are more significant than those for the period of the 1970s–2001. The accelerated changes in areas of...

  10. Post Audit of Lake Michigan Lake Trout PCB Model Forecasts

    Science.gov (United States)

    The Lake Michigan (LM) Mass Balance Study was conducted to measure and model polychlorinated biphenyls (PCBs) and other anthropogenic substances to gain a better understanding of the transport, fate, and effects of these substances within the system and to aid managers in the env...

  11. Changes in Glaciers and Glacial Lakes and the Identification of Dangerous Glacial Lakes in the Pumqu River Basin, Xizang (Tibet

    Directory of Open Access Journals (Sweden)

    Tao Che

    2014-01-01

    Full Text Available Latest satellite images have been utilized to update the inventories of glaciers and glacial lakes in the Pumqu river basin, Xizang (Tibet, in the study. Compared to the inventories in 1970s, the areas of glaciers are reduced by 19.05% while the areas of glacial lakes are increased by 26.76%. The magnitudes of glacier retreat rate and glacial lake increase rate during the period of 2001–2013 are more significant than those for the period of the 1970s–2001. The accelerated changes in areas of the glaciers and glacial lakes, as well as the increasing temperature and rising variability of precipitation, have resulted in an increased risk of glacial lake outburst floods (GLOFs in the Pumqu river basin. Integrated criteria were established to identify potentially dangerous glacial lakes based on a bibliometric analysis method. It is found, in total, 19 glacial lakes were identified as dangerous. Such finding suggests that there is an immediate need to conduct field surveys not only to validate the findings, but also to acquire information for further use in order to assure the welfare of the humans.

  12. Age, growth, mortality, and abundance of lake sturgeon in the Grasse River, New York, USA

    Science.gov (United States)

    Trested, D.G.; Isely, J.J.

    2011-01-01

    An increased understanding of lake sturgeon (Acipenser fulvescens) population dynamics is a key requirement for successful management efforts. Little is known regarding the Grasse River population of lake sturgeon except that it is one of a few populations in New York State where spawning has been documented. Thus our purpose was to assess the current status of lake sturgeon in the Grasse River system, including age, growth, mortality, and abundance. Age was determined for 196 of 211 lake sturgeon by examination of sectioned pectoral fin rays. Ages ranged from 0 to 32 years and the annual mortality rate for fish between ages 7 and 14 was 16.8%. The weight (W, g) to total length (TL, mm) relationship was W = 1.281 x 10-6TL3.202. The von Bertalanffy growth equation was TL = 1913(1-e-0.0294(t+9.5691)). While the range of observed ages was similar to that of nearby St. Lawrence River populations, mean weight at age for an individual at 1000 mm TL was lower than that observed for lake sturgeon within Lake St. Francis of the St. Lawrence River. Predicted growth based on von Bertalanffy parameters was similar to that observed for the nearby Lake St. Francis. An open population estimator using the POPAN sub-module in the Program MARK produced an abundance estimate of 793 lake sturgeon (95% CI = 337-1249).

  13. 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

  14. Relationships between water quality parameters in rivers and lakes: BOD5, COD, NBOPs, and TOC.

    Science.gov (United States)

    Lee, Jaewoong; Lee, Seunghyun; Yu, Soonju; Rhew, Doughee

    2016-04-01

    Biological oxygen demand (BOD5) or chemical oxygen demand (COD) analysis is widely used to evaluate organic pollutants in water systems as well as the efficiency of wastewater treatment plants. However, both analysis methods have restrictions such as being insensitive, imprecise, time-consuming, and the production of chemical waste. Therefore, total organic carbon (TOC) analysis for organic pollutants has been considered for an alternative analysis instead of BOD5 or COD. Several studies have investigated the replacement of BOD5 or COD with TOC in wastewater samples; however, few studies have investigated the relationships between water quality parameters in rivers and lakes. Therefore, this study evaluated the relationships between BOD5, COD, or NBOPs and TOC by the analysis of national water quality monitoring data of rivers and lakes for 5 years. High correlation coefficients (r) of 0.87 and 0.66 between BOD5 and TOC (p TOC (p TOC was 0.93 for rivers and 0.72 for lakes. The coefficients of determination (R 2) were 0.75 and 0.44 between BOD5 and TOC for rivers and lakes as well as were 0.87 and 0.57 between COD and TOC for rivers and lakes, respectively. The coefficient of determination (R 2) between NBOPs and TOC was 0.73 for rivers and 0.52 for lakes.

  15. 76 FR 65609 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-10-24

    ... CFR Part 165 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago, IL AGENCY: Coast... of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des Plaines River,...

  16. Sources of Heavy Metal Pollution into the St. Louis River, Lake Superior Watershed

    Science.gov (United States)

    Sternberg, S. P.; Palokangas, C.

    2013-12-01

    The St. Louis River begins in Hoyt Lakes, Minnesota and enters Lake Superior between Duluth, Minnesota and Superior, Wisconsin. The Partridge River and the Embarrass River are two of its main tributaries. National Pollutant Discharge Elimination System (NPDES) permits are issued for surface water dischargers under the Clean Water Act. The Permit Compliance System (PCS) and the Integrated Compliance Information System (ICIS) is a tool allowing public access to information contained in NPDES permits. Along the way to Lake Superior, 19 facilities list the St. Louis River, St. Louis Bay, part of the St. Louis River estuary, or one of its tributaries as a receiving water. Of these 19 locations, four report discharging heavy metals into the receiving water. Copper and Lead are the metals most frequently discharged.

  17. Stochastic Modelling of River Geometry

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Schaarup-Jensen, K.

    1996-01-01

    Numerical hydrodynamic river models are used in a large number of applications to estimate critical events for rivers. These estimates are subject to a number of uncertainties. In this paper, the problem to evaluate these estimates using probabilistic methods is considered. Stochastic models...

  18. Southwestern Alaska archeological survey, Kagati Lake, Kisarilik-Kwethluk Rivers: A final research report to the National Geographic Society

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Discusses archeological survey of the east of Kagati Lake to Nenevok Lake, north to Trail Creek and Kwethluk River valleys, west along the Kwethluk and Kisaralik...

  19. Evaluation of an operational water cycle prediction system for the Laurentian Great Lakes and St. Lawrence River

    Science.gov (United States)

    Fortin, Vincent; Durnford, Dorothy; Smith, Gregory; Dyck, Sarah; Martinez, Yosvany; Mackay, Murray; Winter, Barbara

    2017-04-01

    Environment and Climate Change Canada (ECCC) is implementing new numerical guidance products based on fully coupled numerical models to better inform the public as well as specialized users on the current and future state of various components of the water cycle, including stream flow and water levels. Outputs from this new system, named the Water Cycle Prediction System (WCPS), have been available for the Great Lakes and St. Lawrence River watershed since June 2016. WCPS links together ECCC's weather forecasting model, GEM, the 2-D ice model C-ICE, the 3-D lake and ocean model NEMO, and a 2-D hydrological model, WATROUTE. Information concerning the water cycle is passed between the models at intervals varying from a few minutes to one hour. It currently produces two forecasts per day for the next three days of the complete water cycle in the Great Lakes region, the largest freshwater lake system in the world. Products include spatially-varying precipitation, evaporation, river discharge, water level anomalies, surface water temperatures, ice coverage, and surface currents. These new products are of interest to water resources and management authority, flood forecasters, hydroelectricity producers, navigation, environmental disaster managers, search and rescue teams, agriculture, and the general public. This presentation focuses on the evaluation of various elements forecasted by the system, and weighs the advantages and disadvantages of running the system fully coupled.

  20. Landsat ETM+ images in the estimation of seasonal lake water quality in boreal river basins.

    Science.gov (United States)

    Kallio, Kari; Attila, Jenni; Härmä, Pekka; Koponen, Sampsa; Pulliainen, Jouni; Hyytiäinen, Ulla-Maija; Pyhälahti, Timo

    2008-09-01

    We investigated the use of Landsat ETM+ images in the monitoring of turbidity, colored dissolved organic matter (CDOM), and Secchi disk transparency (Z(SD)) in lakes of two river basins located in southern Finland. The ETM+ images were acquired in May, June, and September 2002 and were corrected for atmospheric disturbance using the simplified method of atmospheric correction (SMAC) model. The in situ measurements consisted of water sampling in the largest lake of the region, routine monitoring results for the whole study area, and Z(SD) observations made by volunteers. The ranges of the water quality variables in the dataset were as follows: turbidity, 0.6-25 FNU; absorption coefficient of CDOM at 400 nm, 1.0-12.2 m(-1); Z(SD), 0.5-5.5 m; and chlorophyll a concentration, 2.4-80 microg L(-1). The estimation accuracies of the image-specific empirical algorithms expressed as relative errors were 23.0% for turbidity, 17.4% for CDOM, and 21.1% for Z(SD). If concurrent in situ measurements had not been used for algorithm training, the average error would have been about 37%. The atmospheric correction improved the estimation accuracy only slightly compared with the use of top-of-atmospheric reflectances. The accuracy of the water quality estimates without concurrent in situ measurements could have been improved if in-image atmospheric parameters had been available. The underwater reflectance simulations of the ETM+ channel wavelengths using water quality typical for Finnish lakes (data from 1113 lakes) indicated that region-specific algorithms may be needed in other parts of the country, particularly in the case of Z(SD). Despite the limitations in the spectral and radiometric resolutions, ETM+ imagery can be an effective aid, particularly in the monitoring and management of small lakes (<1 km(2)), which are often not included in routine monitoring programs.

  1. 78 FR 66267 - Safety Zone; HITS Triathlon Series; Colorado River; Lake Havasu, AZ

    Science.gov (United States)

    2013-11-05

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; HITS Triathlon Series; Colorado River; Lake... establishing a safety zone upon the navigable waters of the Colorado River in support of the HITS Triathlon.... is sponsoring the HITS Triathlon Series, which will involve 1,200 swimmers transiting North...

  2. Behavioural and morphological differences between lake and river populations of Salaria fluviatilis

    NARCIS (Netherlands)

    Neat, F.C.; Lengkeek, W.; Westerbeek, P.; Laarhoven, B.; Videler, J.J

    2003-01-01

    Three populations (one from a river and two from lakes) of Salaria fluviatilis, the only exclusively freshwater representative of the Blenniidae, showed significant differences in reproductive behaviour and morphology. Breeding males and females were significantly larger at maturity in the river tha

  3. Modeling toxaphene behavior in the Great Lakes.

    Science.gov (United States)

    Xia, Xiaoyan; Hopke, Philip K; Holsen, Thomas M; Crimmins, Bernard S

    2011-01-15

    Chlorinated camphenes, toxaphene, are persistent organic pollutants of concern in the Great Lakes since elevated concentrations are found in various media throughout the system. While concentrations have decreased since their peak values in the 1970s and 80s, recent measurements have shown that the rate of this decline in Lake Superior has decreased significantly. This modeling study focused on toxaphene cycling in the Great Lakes and was performed primarily to determine if elevated water and fish concentrations in Lake Superior can be explained by physical differences among the lakes. Specifically, the coastal zone model for persistent organic pollutants (CoZMo-POP), a fugacity-based multimedia fate model, was used to calculate toxaphene concentrations in the atmosphere, water, soil, sediment, and biota. The performance of the model was evaluated by comparing calculated and reported concentrations in these compartments. In general, simulated and observed concentrations agree within one order of magnitude. Both model results and observed values indicate that toxaphene concentrations have declined in water and biota since the 1980s primarily as the result of decreased atmospheric deposition rates. Overall the model results suggest that the CoZMo-POP2 model does a reasonable job in simulating toxaphene variations in the Great Lakes basin. The results suggest that the recent findings of higher toxaphene concentrations in Lake Superior can be explained by differences in the physical properties of the lake (primarily large volume, large residence time and cold temperatures) compared to the lower lakes and increased recent inputs are not needed to explain the measured values.

  4. Quality of water in the White River and Lake Tapps, Pierce County, Washington, May-December 2010

    Science.gov (United States)

    Embrey, S.S.; Wagner, R.J.; Huffman, R.L.; Vanderpool-Kimura, A. M.; Foreman, J.R.

    2012-01-01

    The White River and Lake Tapps are part of a hydropower system completed in 1911–12. The system begins with a diversion dam on the White River that routes a portion of White River water into the southeastern end of Lake Tapps, which functioned as a storage reservoir for power generation. The stored water passed through the hydroelectric facilities at the northwestern end of the lake and returned to the White River through the powerhouse tailrace. Power generation ceased in January 2004, which altered the hydrology of the system by reducing volumes of water diverted out of the river, stored, and released through the powerhouse. This study conducted from May to December 2010 created a set of baseline data collected under a new flow regime for selected reaches of the White River, the White River Canal (Inflow), Lake Tapps Diversion (Tailrace) at the powerhouse, and Lake Tapps.

  5. Microbial diversity in the lake Elliðavatn and its rivers in the capital city of Iceland

    OpenAIRE

    Kristín Elísa Guðmundsdóttir 1986

    2012-01-01

    The uniqueness of Elliðaár rivers, situated in Reykjavík is reflected by their origin from the lake Elliðavatn to their estuary, both being within the city limit. Few studies have been carried out on the rivers and lake microbial diversity. The objective of this study was to screen the microbial diversity and presence of faecal indicators in the rivers and lake. Samples were taken from three sampling sites in the lake and six sampling sites in the rivers four times over a nine-month period. T...

  6. The Response of Lake to Glacier in Akesu River-Kaidu River Small Watershed during 30 Years

    Science.gov (United States)

    Cui, Hanwen; Jiang, Qigang

    2017-01-01

    Glacier is a sensitive indicator of the climate change, and also closely related to human beings. RS and GIS supply effective means to research the change of glacier. Those are important methods for compensating the shortage of previous ones. Small watershed is the basic unit of water circulation. Thus, the more reliable conclusion, which is the response of lake to glacier, will be obtained by the small watershed. In this paper, dividing the watershed into the smaller one, the Akesu River-Kaidu River small watershed was chosen as study area. Based on RS and GIS, under the climate change from cold-dry to warm-wet since 1977, 2000 and 2007, the variety of glacier was shown as decreasing firstly and then increasing a little. Meanwhile, the variety of lake was presented as increasing firstly and then decreasing greatly. However, the change tendency of glacier and lake was decreased. The decreased areas were 823.3 km2 and 239.5km2 separately. According to the spatial bivariate auto-correlation analysis map, the negative correlation between glacier and lake was more distinct. In Tianshan Mountain, owing to the change mainly influenced by elevation, glacier was decreased and lake was increased. In Bosten Lake, glacier was increased and lake was decreased due to the change mainly affected by climate.

  7. Glacial lakes in the Horgos river basin and their outbreak risk assessment

    OpenAIRE

    A. P. Medeu; T. G. Tokmagambetov; A. L. Kokarev; P. A. Plekhanov; N. S. Plekhanova

    2013-01-01

    The river Khorgos (in Kazakhstan – Korgas) is a boundary river between Kazakhstan and China. Its basin is located in the central part of southern slope of Dzhungarskiy (Zhetysu) Alatau range. According to agreement between Kazakhstan and China at the boundary transition of Khorgos in the floodplain of the river Khorgos the large Center of Frontier Cooperation is erected. Estimation of safety of the mentioned object including connection with possible glacial lakes outbursts has the importance ...

  8. Numerical modeling of the spring thermal bar and pollutant transport in a large lake

    Science.gov (United States)

    Tsydenov, Bair O.; Kay, Anthony; Starchenko, Alexander V.

    2016-08-01

    The spring riverine thermal bar phenomenon is investigated numerically on an example of Lake Baikal, and the spread of pollutants coming from the Selenga River is forecast using the 2.5 D non-hydrostatic model in the Boussinesq approximation. This hydrodynamic model takes into account the diurnal variability of the heat fluxes on the lake surface and the effects of wind and the Earth's rotation. The results of numerical modeling show that the variability of the total heat flux over 24 h plays a significant role in the variation of the thermal bar movement rate that contributes to the rapid mixing of impurities entering with river water.

  9. Ecosystem health assessment of urban rivers and lakes-Case study of "the six lakes" in Beijing,China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The assessment of the ecosystem health of urban rivers and lakes is the scientific basis for their management and ecological restoration.This study developed a three-level indicator system for its assessment.The results indicated that:Zhonghai and Nanhai are in the state of transition from unhealthy to critical state and all the other lakes are in unhealthy states.Water environmental quality,structure and function of the aquatic ecosystem,and the structure of waterfront areas were the constraints.Nanhai was ranked as poor and the others were all ranked as very poor.However,the ecological environment of Zhonghai and Nanhai were better than the others,the sums of the degree of membership to the healthy state and critical state were all close to 0.6.and the restorations of these lakes were moderate.The sums of the degree of membership to the healthy state and critical state of the other lakes were under 0.3,as it was difficult to restore these lakes.Some suggestions on scientific management and ecological restoration of the six lakes were improve the water quality of six lakes and the water ecosystem and waterfront areas.

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

    Science.gov (United States)

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

    2014-01-01

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

  11. Phosphorus forms and bioavailability of lake sediments in the middle and lower reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    ZHU; Guangwei; QIN; Boqiang; ZHANG; Lu

    2006-01-01

    Forms of phosphorus in sediments from 25 lakes in the middle and lower reaches of Yangtze River were analyzed by the sequential extraction procedure. Contents and spatial distrubution of algal available phosphorus (AAP) in sediments of Lake Taihu, the third largest freshwater lake of China, were also studied. Relationships between phosphorus forms in sediment and macrophytes coverage in sample sites, as well as phosphorus forms in sediments and chlorophyal contents in lake water were discussed. Exchangeable form of phosphorus (Ex-P) in surface sediments was significantly positive correlative to total phosphorus (TP), dissolved total phosphorus (DTP) and soluble reactive phosphorus (SRP) contents in the lake water. Bioavailable phosphorus (Bio-P) contents in sediments from macrophytes dominant sites were significantly lower than that in no macrophyte sites. In Lake Taihu, Ex-P content in top 3 cm sediment was highest.However, content of ferric fraction phosphorus (Fe-P) was highest in 4-10 cm. Bioavalilble phosphorus (Bio-P) contents in surface sediments positively correlated to Chlorophyll a contents in water of Lake Taihu with significant difference. Therefore, contents of Bio-P and AAP could be acted as the indicators of risks of internal release of phosphorus in the shallow lakes. It was estimated that there were 268.6 ton AAP in top 1 cm sediments in Lake Taihu. Sediment suspension caused by strong wind-induced wave disturbance could carry plenty of AAP into water in large shallow lakes like Lake Taihu.

  12. Impact of river-lake-groundwater interaction on boundless carbon cycle in continental basin

    Science.gov (United States)

    Nakayama, T.; Shankman, D.

    2012-12-01

    In the Changjiang River in south China, deforestation and land reclamation have induced serious soil erosion and increased floods. Although the Three Gorges Dam (TGD) will provide flood control, the aquatic environment might be changed by discharge control and pollutant loads caused by the deposition of large amounts of sediment in the upper dam (Yang et al., 2006). Some research implies that seepage of groundwater along the lower regions plays important role in maintaining stream flow and after TGD impounding by using natural radionuclides (Dai et al., 2010). It is effective to clarify complicated river-lake-groundwater interaction (Eltahir and Yeh, 1999; Dai et al., 2010), and to evaluate optimum amount of transferred water and environmental consequences in the basin. The authors have so far developed the process-based National Integrated Catchment-based Eco-hydrology (NICE) model (Nakayama, 2008a, 2008b, 2010, 2011a-b, 2012a-c; Nakayama and Fujita, 2010; Nakayama and Hashimoto, 2011; Nakayama and Watanabe, 2004, 2006, 2008a, 2008b; Nakayama et al., 2006, 2007, 2010, 2012), which includes complex interactions between the forest canopy, surface water, the unsaturated zone, aquifers, lakes, and rivers. The objective of this research is to estimate the impact of river-lake-groundwater interaction on hydrologic cycle and to predict the impact of TGD on the hydrologic change in the downstream Dongting and Poyang Lakes region by using a process-based model. Analysis of power spectra in river discharge also helps to understand its complex mechanism. This integrated system also throws some light on the improvement in boundless biogeochemical cycle along terrestrial-aquatic continuum (Cole et al., 2007). References; Cole, J.J. et al., Ecosystems, doi:10.1007/s10021-006-9013-8, 2007. Dai, Z. et al., Hydrogeol. J., 18, 359-369, 2010. Eltahir, E.A.B.& Yeh, P.J.-F., Water Resour. Res., 35(4), 1199-1217, 1999. Nakayama, T., Ecol. Model., doi:10.1016/j.ecolmodel.2008

  13. Water quality of the Tlikakila River and five major tributaries to Lake Clark, Lake Clark National Park and Preserve, Alaska, 1999-2001

    Science.gov (United States)

    Brabets, Timothy P.

    2002-01-01

    The Tlikakila River Basin, located in Lake Clark National Park and Preserve, drains an area of 622 square miles. This watershed comprises about 21 percent of the Lake Clark Basin, making it one of the major tributaries to Lake Clark. Due to a sharp decline in sockeye salmon population and the lack of hydrologic data, the Tlikakila River and five other major tributaries to Lake Clark were studied during the summer runoff months (May through September) from 1999 through 2001 as part of a cooperative study with the National Park Service. Measurements of pH and dissolved oxygen concentrations of the Tlikakila River are within acceptable limits for fish survival. Water temperatures at the measurement site reach 0 ?C during the winter and this part of the Tlikakila River may not be suitable for fish. Water temperatures are within acceptable limits for fish during the summer months. The Tlikakila River is a calcium bicarbonate type water with a low buffering capacity. Concentrations of un-ionized ammonia are well below the recommended value of 0.02 mg/L for fish propagation. Annual transport of suspended sediment by the Tlikakila River into Lake Clark ranged from 0.4 to 1.5 million tons during 1999?2001. The fine sediment from the Tlikakila River disperses through the lake over the summer, affecting light transmissivity. Most runoff from the Tlikakila River occurs from mid-to-late May through September. Average discharge for these months during 1999?2001 was 6,600 ft?/s. Total annual inflow to Lake Clark from the Tlikakila River ranged from 32 to 45 percent of the total inflow. The relatively high proportion of inflow is due to the presence of glaciers, which comprise 36 percent of the watershed. Monthly measurements of flow, field water-quality parameters, alkalinity, and suspended sediment were collected on the remaining five tributaries to Lake Clark: the Chokotonk River, Currant Creek, the Kijik River, the Tanalian River and the Chulitna River. Similar to the

  14. A Topological Phase Transition in Models of River Networks

    Science.gov (United States)

    Oppenheim, Jacob; Magnasco, Marcelo

    2012-02-01

    The classical Scheidegger model of river network formation and evolution is investigated on non-Euclidean geometries, which model the effects of regions of convergent and divergent flows - as seen around lakes and drainage off mountains, respectively. These new models may be differentiated by the number of basins formed. Using the divergence as an order parameter, we see a phase transition in the number of distinct basins at the point of a flat landscape. This is a surprising property of the statistics of river networks and suggests significantly different properties for riverine networks in uneven topography and vascular networks of arteries versus those of veins among others.

  15. Historical trophic evolutions and their ecological responses from shallow lakes in the middle and lower reaches of the Yangtze River: Case studies on Longgan Lake and Taibai Lake

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The evolutions of diatom floras and the total phosphorous (TP) concentrations in the historical period were reconstructed for two lakes, Longgan and Taibai in the middle Yangtze River,based on high resolutional fossil diatom study from two sediment cores and an established regional diatom-TP transfer function. The TP concentration in Longgan Lake changed slightly in the range of 36-62 μg/L and kept its middle trophic level in the past 200 years. The changes of diatom assemblages reflect a macrophyte-dominated history of the lake. During the nineteenth century, the lake TP concentration increased comparatively, corresponding to the increase in abundance of benthic diatoms. The progressive increase of epiphytic diatoms since the onset of the twentieth century indicates the development of aquatic plants, coinciding with the twice drops of water TP level. The TP concentration in Taibai Lake kept a stable status about 50 μg/L before 1953 AD, while diatoms dominated by facultative planktonic Aulacoseira granulata shifted quickly to epiphytic diatom species, indicating a rapid expansion of aquatic vegetation. During 1953-1970 AD, the coverage of aquatic plants decreased greatly inferred by the low abundance of epiphytic diatoms as well as declined planktonic types, and the reconstructed TP concentration shows an obvious rising trend firstly, suggesting the beginning of the lake eutrophication. The lake was in the eutrophic condition after 1970, coinciding with the successive increase of planktonic diatoms. The comparison of the two lakes suggests the internal adjustment and purification function of aquatic plants for nutrients in water. The discrepancy of TP trends in the two lakes after 1960 reflects two different patterns of lake environmental response to human disturbance. Sediments in Taibai Lake clearly recorded the process of lake ecological transformation from the macrophyte-dominated stage to the algae-dominated stage. The limits of TP concentration (68-118

  16. Convective heat discharge of Wood River group of springs in the vicinity of Crater Lake, Oregon

    Science.gov (United States)

    Nathenson, Manuel; Mariner, Robert H.; Thompson, J. Michael

    1994-01-01

    Data sets for spring and stream chemistry are combined to estimate convective heat discharge and discharge anomalous amounts of sodium and chloride for the Wood River group of springs south of Crater Lake. The best estimate of heat discharge is 87 MWt based on chloride inventory; this value is 3-5 times the heat input to Crater Lake itself. Anomalous discharges of sodium and chloride are also larger that into Crater Lake. Difference between the chemical and thermal characteristics of the discharge into Crater Lake and those from the Wood River group of springs suggest that the heat sources for the two systems may be different, although both ultimately related to the volcanic system.

  17. Study of tributary inflows in Lake Iseo with a rotating physical model

    Directory of Open Access Journals (Sweden)

    Marco Pilotti

    2014-03-01

    Full Text Available The influence of Coriolis force on the currents of large lakes is well acknowledged; very few contributions, however, investigate this aspect in medium-size lakes where its relevance could be questionable. In order to study the area of influence of the two major tributary rivers in Lake Iseo, a rotating vertically distorted physical model of the northern part of this lake was prepared and used, respecting both Froude and Rossby similarity. The model has a horizontal length scale factor of 8000 and a vertical scale factor of 500 and was used both in homogeneous and in thermally stratified conditions. We explored the pattern of water circulation in front of the entrance mouth for different hydrologic scenarios at the beginning of spring and in summer. We neglected the influence of winds. The primary purposes of the model were twofold: i to increase our level of knowledge of the hydrodynamics of Lake Iseo by verifying the occurrence of dynamical effects related to the Earth’s rotation on the plume of the two tributaries that enter the northern part of the lake and ii to identify the areas of the lake that can be directly influenced by the tributaries’ waters, in order to provide guidance on water quality monitoring in zones of relevant environmental and touristic value. The results of the physical model confirm the relevant role played by the Coriolis force in the northern part of the lake. Under ordinary flow conditions, the model shows a systematic deflection of the inflowing waters towards the western shore of the lake. The inflow triggers a clockwise gyre within the Lovere bay, to the West of the inflow, and a slow counter-clockwise gyre, to the East of the inflow, that returns water towards the river mouth along the eastern shore. For discharges with higher return period, when only the contribution by Oglio River is relevant, the effect of the Earth’s rotation weakens in the entrance zone and the plume has a more rectilinear pattern

  18. A Town Of Rivers And Lakes In My Dream Li Ronghua’s Watercolour Paintings

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正>I was born on the Yangtze River and went boating, cut reeds, caught fish and raised ducks when I was a child. As time goes by, my memory of childhood has been on the wane, but the river still reflects myself and history as a live mirror.In the past 20 years, I had chances to visit the towns of rivers and lakes in the south of the Yangtze River. I still remember the scene I saw at Wuzheng, Tongxiang City: a

  19. 76 FR 2829 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-01-18

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  20. 75 FR 64147 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-10-19

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  1. 78 FR 36091 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-06-17

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  2. 77 FR 25595 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2012-05-01

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  3. 77 FR 60044 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2012-10-02

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel... Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan...

  4. 78 FR 17099 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-03-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel... Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan...

  5. 76 FR 78161 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-12-16

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  6. 75 FR 73966 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-11-30

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  7. 77 FR 35854 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2012-06-15

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  8. 78 FR 40635 - Safety Zone; Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-07-08

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone; Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  9. 76 FR 63199 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-10-12

    ... No. USCG-2011-0228] Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago, IL... enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including Des...

  10. 75 FR 64673 - Safety Zone, Brandon Road Lock and, Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-10-20

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Brandon Road Lock and, Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone, Brandon Road Lock and Dam to Lake Michigan including...

  11. 77 FR 65478 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

    Science.gov (United States)

    2012-10-29

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel... Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan...

  12. 78 FR 49684 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-08-15

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel... Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan...

  13. 78 FR 65874 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-11-04

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel... Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan...

  14. 78 FR 4071 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-01-18

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel... Guard will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan...

  15. 76 FR 23524 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2011-04-27

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel... proposes to establish a permanent safety zone from Brandon Road Lock and Dam to Lake Michigan....

  16. 78 FR 36092 - Safety Zone; Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2013-06-17

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone; Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  17. 75 FR 52462 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-08-26

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Brandon Road Lock and Dam to Lake Michigan Including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  18. 77 FR 20295 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

    Science.gov (United States)

    2012-04-04

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel, Chicago... will enforce a segment of the Safety Zone; Brandon Road Lock and Dam to Lake Michigan including...

  19. Phytoplankton Community Dynamics in West Lake After Drawing Water from the Qiantang River

    Institute of Scientific and Technical Information of China (English)

    魏印心; 李瑾; 虞左明

    2004-01-01

    Seventeen phytoplankton dominant species of 218 taxa were found to have contributed to more than 80% of the biomass after analysis of the January, 1955 to December, 1996 phytoplankton population at five stations in West Lake after Qiantang River water had been drawn into the lake for a decade. The seasonal fluctuations were obvious; the maximum cell density of 90.91×107-93.58×107 cells/L and biomass of 57.41-58.61 mg/L occurred mainly in summer of 1996,largely as a result of the development of Lyngbya contorta, Merismopedia tenuissima, Oscillatoria limnetica, Spirulina laxissima and Scenedesmus quadricauda, etc. at Stations 2 and 4. At Station 1 located near the inlet for drawing water from the Qiantang River, the species number, cell density, biomass, chlorophyll a concentration and physico-chemical parameters (except for total nitrogen) were obviously greater than those at the other four stations, also greater than the corresponding parameters before the drawing of water from the Qiantang River into the lake.Compared with the results of study on the phytoplankton community in 1980 before the drawing of Qiantang River into the lake, the species number and the total individual density were increased, the dominant species changed somewhat, the biomass was decreased. The water quality was improved (especially at Station 1) after the drawing of river water into the lake.Based on criteria for evaluating trophic status, the biological and chemical indicators such as species composition and dominant species, and other parameters such as annual mean value cell densities (36.06×107-51.27×107 cells/L), biomass (29.03-39.74 mg/L), chl a concentrations (41.29-67.67μg/L), total nitrigen (1.72-2.89 mg/L), total phosphorus (0.12-0.16 mg/L) obtained at Stations 2, 3, 4 and 5, showed that West Lake is still at eutrophic lake.

  20. A heuristic simulation model of Lake Ontario circulation and mass balance transport

    Science.gov (United States)

    McKenna, J.E.; Chalupnicki, M.A.

    2011-01-01

    The redistribution of suspended organisms and materials by large-scale currents is part of natural ecological processes in large aquatic systems but can contribute to ecosystem disruption when exotic elements are introduced into the system. Toxic compounds and planktonic organisms spend various lengths of time in suspension before settling to the bottom or otherwise being removed. We constructed a simple physical simulation model, including the influence of major tributaries, to qualitatively examine circulation patterns in Lake Ontario. We used a simple mass balance approach to estimate the relative water input to and export from each of 10 depth regime-specific compartments (nearshore vs. offshore) comprising Lake Ontario. Despite its simplicity, our model produced circulation patterns similar to those reported by more complex studies in the literature. A three-gyre pattern, with the classic large counterclockwise central lake circulation, and a simpler two-gyre system were both observed. These qualitative simulations indicate little offshore transport along the south shore, except near the mouths of the Niagara River and Oswego River. Complex flow structure was evident, particularly near the Niagara River mouth and in offshore waters of the eastern basin. Average Lake Ontario residence time is 8 years, but the fastest model pathway indicated potential transport of plankton through the lake in as little as 60 days. This simulation illustrates potential invasion pathways and provides rough estimates of planktonic larval dispersal or chemical transport among nearshore and offshore areas of Lake Ontario. ?? 2011 Taylor & Francis.

  1. Digital elevation model of Walker Lake, West-Central Nevada

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Walker Lake lies within a topographically closed basin in west-central Nevada and is the terminus of the Walker River. Accurately determining the bathymetry and...

  2. The chemistry of river-lake systems in the context of permafrost occurrence (Mongolia, Valley of the Lakes). Part I. Analysis of ion and trace metal concentrations

    Science.gov (United States)

    Szopińska, Małgorzata; Szumińska, Danuta; Polkowska, Żaneta; Machowiak, Katarzyna; Lehmann, Sara; Chmiel, Stanisław

    2016-07-01

    This study provides a description of water chemistry in river-lake systems located in central Mongolia, at the borderline of permafrost occurrence. The analysis involved water samples collected from two river-lake systems: Baydrag River-Böön Tsagaan Lake system, and Shargalyuut/Tuyn Rivers-Orog Lake system. In the water samples, ions and trace elements were detected and quantified. Additionally, the parameters of pH, electrical conductivity (SEC), total dissolved solids (TDS) and total organic carbon (TOC) were determined. Principal Component Analysis (PCA) was performed on the sample results. Water chemistry is mostly influenced by geochemical and hydrometeorological processes. Permafrost thawing could increase the concentration of nitrogen (NH4+, NO3-) as well as Na+ and Ca2+, Cl- and SO42 -. However, it may also be an effect of other factors such as livestock farming. Seasonal drying out of lakes (e.g., Lake Orog) may also influence water chemistry by deflation of evaporites from exposed lake beds and, at the same time, with lower concentration of chemical compounds in water. The PCA shows that water samples can be divided into two groups. The first group contains lake samples, where water chemistry is shaped by prevailing evaporation processes, whereas the second includes samples from rivers and springs. Water chemistry of the latter is predominantly influenced by geochemical and hydro-meteorological processes.

  3. Variability of the water availability in a river lake system – A case study of Lake Symsar

    Directory of Open Access Journals (Sweden)

    Kuriata-Potasznik Angela B.

    2016-12-01

    Full Text Available It is predicted that climate change will result in the diminution of water resources available both on global and regional scales. Local climate change is harder to observe and therefore, while counteracting its effects, it seems advisable to undertake studies on pertinent regional and local conditions. In this research, our aim was to assess the impact of a river and its catchment on fluctuations in the water availability in a natural lake which belongs to a post-glacial river and lake system. River and lake systems behave most often like a single interacting hydrological unit, and the intensity of water exchange in these systems is quite high, which may cause temporary water losses. This study showed that water in the analyzed river and lake system was exchanged approx. every 66 days, which resulted from the total (horizontal and vertical water exchange. Also, the management of a catchment area seems to play a crucial role in the local water availability, as demonstrated by this research, where water retention was favoured by wooded and marshy areas. More intensive water retention was observed in a catchment dominated by forests, pastures and wetlands. Wasteland and large differences in the land elevation in the tested catchment are unfavourable to water retention because they intensify soil evaporation and accelerate the water run-off outside of the catchment. Among the actions which should be undertaken in order to counteract water deficiencies in catchment areas, rational use and management of the land resources in the catchment are most often mentioned.

  4. The chemistry of river-lake systems in the context of permafrost occurrence (Mongolia, Valley of the Lakes) Part II. Spatial trends and possible sources of organic composition

    Science.gov (United States)

    Szopińska, Małgorzata; Dymerski, Tomasz; Polkowska, Żaneta; Szumińska, Danuta; Wolska, Lidia

    2016-07-01

    The chemistry of river-lake systems located in Central Mongolia near the southern border of permafrost occurrence has not been well studied. The main aim of this paper is to summarize patterns in water chemistry in supply springs, rivers and lakes in relation to permafrost occurrence, as well as other natural and anthropogenic impacts. The analyses involved water samples taken from two river-lake systems: the Baydrag River-Böön Tsagaan Lake system and the Shargalyuut/Tuyn Rivers-Orog Lake system. Total organic carbon (TOC) and polycyclic aromatic hydrocarbons (PAHs) were detected and quantified. Other organic compounds, such as organic halogen compounds, phthalates, and higher alkanes were also noted. The main factors which influence differences in TOC concentrations in the water bodies involve permafrost occurrence, mainly because compounds are released during active layer degradation (in the upper reach of the Tuyn river), and by intensive livestock farming in river valleys and in the vicinity of lakes. In relation to the concentrations of PAHs, high variability between samples (> 300 ng L- 1), indicates the influence of thermal water and local geology structures (e.g., volcanic and sedimentary deposits), as well as accumulation of suspended matter in lakes transported during rapid surface runoff events. The monitoring of TOC as well as individual PAHs is particularly important to future environmental studies, as they may potentially reflect the degradation of the environment. Therefore, monitoring in the Valley of the Lakes should be continued, particularly in the light of the anticipated permafrost degradation in the 21st century, in order to collect more data and be able to anticipate the response of river-lake water chemistry to changes in permafrost occurrence.

  5. Modelling river history and evolution.

    Science.gov (United States)

    Coulthard, T J; Van de Wiel, M J

    2012-05-13

    Over the last few decades, a suite of numerical models has been developed for studying river history and evolution that is almost as diverse as the subject of river history itself. A distinction can be made between landscape evolution models (LEMs), alluvial architecture models, meander models, cellular models and computational fluid dynamics models. Although these models share some similarities, there also are notable differences between them, which make them more or less suitable for simulating particular aspects of river history and evolution. LEMs embrace entire drainage basins at the price of detail; alluvial architecture models simulate sedimentary facies but oversimplify flow characteristics; and computational fluid dynamics models have to assume a fixed channel form. While all these models have helped us to predict erosion and depositional processes as well as fluvial landscape evolution, some areas of prediction are likely to remain limited and short-term owing to the often nonlinear response of fluvial systems. Nevertheless, progress in model algorithms, computing and field data capture will lead to greater integration between these approaches and thus the ability to interpret river history more comprehensively.

  6. Lake Michigan lake trout PCB model forecast post audit (oral presentation)

    Science.gov (United States)

    Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents an...

  7. Simulation and Evaluation of Pollution Load Reduction Scenarios for Water Environmental Management: A Case Study of Inflow River of Taihu Lake, China

    Directory of Open Access Journals (Sweden)

    Ruibin Zhang

    2014-09-01

    Full Text Available In the beginning of the 21st century, the deterioration of water quality in Taihu Lake, China, has caused widespread concern. The primary source of pollution in Taihu Lake is river inflows. Effective pollution load reduction scenarios need to be implemented in these rivers in order to improve the water quality of Taihu Lake. It is important to select appropriate pollution load reduction scenarios for achieving particular goals. The aim of this study was to facilitate the selection of appropriate scenarios. The QUAL2K model for river water quality was used to simulate the effects of a range of pollution load reduction scenarios in the Wujin River, which is one of the major inflow rivers of Taihu Lake. The model was calibrated for the year 2010 and validated for the year 2011. Various pollution load reduction scenarios were assessed using an analytic hierarchy process, and increasing rates of evaluation indicators were predicted using the Delphi method. The results showed that control of pollution from the source is the optimal method for pollution prevention and control, and the method of “Treatment after Pollution” has bad environmental, social and ecological effects. The method applied in this study can assist for environmental managers to select suitable pollution load reduction scenarios for achieving various objectives.

  8. Simulation and evaluation of pollution load reduction scenarios for water environmental management: a case study of inflow river of Taihu Lake, China.

    Science.gov (United States)

    Zhang, Ruibin; Qian, Xin; Zhu, Wenting; Gao, Hailong; Hu, Wei; Wang, Jinhua

    2014-09-09

    In the beginning of the 21st century, the deterioration of water quality in Taihu Lake, China, has caused widespread concern. The primary source of pollution in Taihu Lake is river inflows. Effective pollution load reduction scenarios need to be implemented in these rivers in order to improve the water quality of Taihu Lake. It is important to select appropriate pollution load reduction scenarios for achieving particular goals. The aim of this study was to facilitate the selection of appropriate scenarios. The QUAL2K model for river water quality was used to simulate the effects of a range of pollution load reduction scenarios in the Wujin River, which is one of the major inflow rivers of Taihu Lake. The model was calibrated for the year 2010 and validated for the year 2011. Various pollution load reduction scenarios were assessed using an analytic hierarchy process, and increasing rates of evaluation indicators were predicted using the Delphi method. The results showed that control of pollution from the source is the optimal method for pollution prevention and control, and the method of "Treatment after Pollution" has bad environmental, social and ecological effects. The method applied in this study can assist for environmental managers to select suitable pollution load reduction scenarios for achieving various objectives.

  9. Modeling Hydrodynamics, Water Temperature, and Suspended Sediment in Detroit Lake, Oregon

    Science.gov (United States)

    Sullivan, Annett B.; Rounds, Stewart A.; Sobieszczyk, Steven; Bragg, Heather M.

    2007-01-01

    Detroit Lake is a large reservoir on the North Santiam River in west-central Oregon. Water temperature and suspended sediment are issues of concern in the river downstream of the reservoir. A CE-QUAL-W2 model was constructed to simulate hydrodynamics, water temperature, total dissolved solids, and suspended sediment in Detroit Lake. The model was calibrated for calendar years 2002 and 2003, and for a period of storm runoff from December 1, 2005, to February 1, 2006. Input data included lake bathymetry, meteorology, reservoir outflows, and tributary inflows, water temperatures, total dissolved solids, and suspended sediment concentrations. Two suspended sediment size groups were modeled: one for suspended sand and silt with particle diameters larger than 2 micrometers, and another for suspended clay with particle diameters less than or equal to 2 micrometers. The model was calibrated using lake stage data, lake profile data, and data from a continuous water-quality monitor on the North Santiam River near Niagara, about 6 kilometers downstream of Detroit Dam. The calibrated model was used to estimate sediment deposition in the reservoir, examine the sources of suspended sediment exiting the reservoir, and examine the effect of the reservoir on downstream water temperatures.

  10. Modeling Water Quantity and Quality in the Devils Lake Watershed Coupling SWAT and CE-QUAL-W2.

    Science.gov (United States)

    Shabani, A.; Zhang, X.; Ell, M.

    2016-12-01

    Devils Lake is a terminal lake in the sub-basin of the Red River of the North basin in northeastern North Dakota. During the last two decades, the lake level has risen by nearly 10 m, causing floods that have costed more than 1 billion USD in mitigation measures. Another increase of approximate 1.5 m in the lake level would cause water to spill naturally into the Sheyenne River. To alleviate this potential yet catastrophic spillage, two artificial outlets were constructed. However, artificially draining water to the Sheyenne River raises a concern of water quality because the Devils Lake water contains significantly higher concentrations of dissolved solids, particularly sulfate, than the surrounding water bodies. In this study, the Soil and Water Assessment Tool (SWAT) coupled with CE-QUAL-W2 were used to simulate water quantity and quality over the watershed and the lake. The SWAT model performed well to simulate daily flow, total suspend sediment (TSS), total nitrogen (TN), and phosphorous (TP) in the tributaries. The developed SWAT model is able to simulate to the lake level with a root mean square error of 0.35 m for the period time from 1995 to 2014.The CE-QUAL-W2 successfully simulated sulfate concentration (R2=0.4 and PBIAS < 6%) and concentrations of TP in the lake that are in general agreement with the observations. Keywords: Devils Lake, flooding, SWAT, CE-QUAL-W2, water quality

  11. Demographic analysis of Lost River sucker and shortnose sucker populations in Upper Klamath Lake, Oregon

    Science.gov (United States)

    Janney, E.C.; Shively, R.S.; Hayes, B.S.; Barry, P.M.; Perkins, D.

    2008-01-01

    We used 13 years (1995-2007) of capture-mark-recapture data to assess population dynamics of endangered Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris in Upper Klamath Lake, Oregon. The Cormack-Jolly-Seber method was used to estimate survival, and information theoretic modeling was used to assess variation due to time, gender, species, and spawning subpopulations. Length data were used to detect multiple year-class failures and events of high recruitment into adult spawning populations. Average annual survival probability was 0.88 for Lost River suckers and 0.76 for shortnose suckers. Mean life span estimates based on these survival rates indicated that Lost River suckers survived long enough on average to attempt reproduction eight times, whereas shortnose suckers only survived to spawn three to four times. Shortnose sucker survival was not only poor in years of fish kills (1995-1997) but also was low in years without fish kills (i.e., 2002 and 2004). This suggests that high mortality occurs in some years but is not necessarily associated with fish kills. Annual survival probabilities were not only different between the two species but also differed between two spawning subpopulations of Lost River suckers. Length composition data indicated that recruitment into spawning populations only occurred intermittently. Populations of both species transitioned from primarily old individuals with little size diversity and consistently poor recruitment in the late 1980s and early 1990s to mostly small, recruit-sized fish by the late 1990s. A better understanding of the factors influencing adult survival and recruitment into spawning populations is needed. Monitoring these vital parameters will provide a quantitative means to evaluate population status and assess the effectiveness of conservation and recovery efforts.

  12. Adult Chinook Salmon Abundance Monitoring in the Secesh River and Lake Creek, Idaho, 2000 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Faurot, Dave; Kucera, Paul A.

    2001-05-01

    Underwater time-lapse video technology has been used to monitor adult spring and summer chinook salmon (Oncorhynchus tshawytscha) escapement into the Secesh River and Lake Creek, Idaho, since 1998. Underwater time-lapse videography is a passive methodology that does not trap or handle this Endangered Species Act listed species. Secesh River chinook salmon represent a wild spawning aggregate that has not been directly supplemented with hatchery fish. The Secesh River is also a control population under the Idaho Salmon Supplementation study. This project has demonstrated the successful application of underwater video adult salmon abundance monitoring technology in Lake Creek in 1998 and 1999. Emphasis of the project in 2000 was to determine if the temporary fish counting station could be installed early enough to successfully estimate adult spring and summer chinook salmon abundance in the Secesh River (a larger stream). Snow pack in the drainage was 93% of the average during the winter of 1999/2000, providing an opportunity to test the temporary count station structure. The temporary fish counting station was not the appropriate technology to determine adult salmon spawner abundance in the Secesh River. Due to its temporary nature it could not be installed early enough, due to high stream discharge, to capture the first upstream migrating salmon. A more permanent structure used with underwater video, or other technology needs to be utilized for accurate salmon escapement monitoring in the Secesh River. A minimum of 813 adult chinook salmon spawners migrated upstream past the Secesh River fish counting station to spawning areas in the Secesh River drainage. Of these fish, more than 324 migrated upstream into Lake Creek. The first upstream migrating adult chinook salmon passed the Secesh River and Lake Creek sites prior to operation of the fish counting stations on June 22. This was 17 and 19 days earlier than the first fish arrival at Lake Creek in 1998 and 1999

  13. Audubon National Wildlife Refuge, Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Wintering River Easement Refuge, Cottonwood Lake Easement Refuge, Sheyenne Lake Easement Refuge : Narrative report : 1969

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Audubon National Wildlife Refuge (including Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Cottonwood Lake...

  14. The Fishery of Truckee River and Pyramid Lake, Nevada

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report provides an overview of the Washoe Project Act. Trout populations in Pyramid Lake began to decline in the 1930s due to poor water quality and poor...

  15. Mirror Lake contaminanats - Lower Columbia River Restoration Action Effectiveness Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 1) The purpose of this project is to measure changes in juvenile salmon habitat occurrence and health following restoration activities at the Mirror Lake Complex and...

  16. Calculation of permissible load capacity and establishment of total amount control in the Wujin River Catchment--a tributary of Taihu Lake, China.

    Science.gov (United States)

    Zhang, Ruibin; Gao, Hailong; Zhu, Wenting; Hu, Wei; Ye, Rui

    2015-08-01

    The deterioration of water quality in Taihu Lake, China, has caused widespread concern in recent years. The primary pollution sources of Taihu Lake are its inflow rivers. Effective environmental water management strategies need to be implemented in these rivers to improve the water quality of Taihu Lake and to promote sustainable development in the region. In this study, the QUAL2K model is used in conjunction with the trial and error approach to assess permissible load capacities for the Wujin River (a major tributary of Taihu Lake) in terms of COD, NH3-N, TN, and TP. Results show that permissible annual loads for these pollutants are 5216.31, 491.71, 948.53, and 104.38 t, respectively. This suggests that COD, NH3-N, TN, and TP loads in the Wujin River catchment need to be reduced by 13.35, 27.26, 47.75, and 37.08 %, respectively, to satisfy national water quality objectives. Total amount control measures are proposed to control and reduce pollution loads of the Wujin River catchment. The method applied in this study should provide a sound basis for water environmental management decision-making.

  17. Measuring water heights in rivers and lakes from lightweight Unmanned Aerial Vehicles (UAVs)

    DEFF Research Database (Denmark)

    Bandini, Filippo; Butts, Michael; Olesen, Daniel Haugård

    and a tracking of the terrestrial water bodies not able to detect water heights in small rivers or lakes; ii) a limited temporal resolution which limits the ability to determine rapid temporal changes, especially during extremes. Unmanned Aerial Vehicles (UAVs) are one technology able to fill the gap between...

  18. Logging the Great Lakes Indian Reservations: The Case of the Bad River Band of Ojibwe

    Science.gov (United States)

    Steen-Adams, Michelle M.; Langston, Nancy E.; Mladenoff, David J.

    2010-01-01

    The harvest of the Great Lakes primary forest stands (ca. 1860-1925) transformed the region's ecological, cultural, and political landscapes. Although logging affected both Indian and white communities, the Ojibwe experienced the lumber era in ways that differed from many of their white neighbors. When the 125,000-acre Bad River Reservation was…

  19. 77 FR 61631 - Final Environmental Impact Statement for Stehekin River Corridor Implementation Plan, Lake Chelan...

    Science.gov (United States)

    2012-10-10

    ... prioritizing potential exchange/ acquisition lands, including scenic resources and threats within debris flow..., maintenance yard) in response to increased flooding and erosion issues in the lower Stehekin River watershed... erosion threats to NPS facilities and are impacting natural resources within Lake Chelan NRA. The...

  20. OVERVIEW OF THE MARK TWAIN LAKE/SALT RIVER BASIN CONSERVATION EFFECTS ASSESSMENT PROJECT

    Science.gov (United States)

    The Mark Twain Lake/Salt River Basin was selected as one of 12 USDA-Agricultural Research Service benchmark watersheds for the Conservation Effects Assessment Project (CEAP) because of documented soil and water quality problems and broad stakeholder interest. The basin is located in northeastern Mis...

  1. The Mark Twain Lake/Salt River CEAP Project – Progress and Preliminary Findings

    Science.gov (United States)

    The Mark Twain Lake collects drainage from approximately 6600 km2 of the Salt River basin, most of which represents the Midwest claypan major land resource area. Thus, it is likely the watershed most prone to surface runoff in the CEAP benchmark network. High surface runoff from agricultural land wi...

  2. 76 FR 61261 - Safety Zone; IJSBA World Finals; Lower Colorado River, Lake Havasu, AZ

    Science.gov (United States)

    2011-10-04

    ... not be hindered by the safety zone. Recreational vessels will not be allowed to transit through the... vessels intending to transit or anchor in a portion of the lower Colorado River at Lake Havasu from... Captain of the Port will cease enforcement of this safety zone and will announce that fact via...

  3. Compilation of watershed models for tributaries to the Great Lakes, United States, as of 2010, and identification of watersheds for future modeling for the Great Lakes Restoration Initiative

    Science.gov (United States)

    Coon, William F.; Murphy, Elizabeth A.; Soong, David T.; Sharpe, Jennifer B.

    2011-01-01

    As part of the Great Lakes Restoration Initiative (GLRI) during 2009–10, the U.S. Geological Survey (USGS) compiled a list of existing watershed models that had been created for tributaries within the United States that drain to the Great Lakes. Established Federal programs that are overseen by the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Army Corps of Engineers (USACE) are responsible for most of the existing watershed models for specific tributaries. The NOAA Great Lakes Environmental Research Laboratory (GLERL) uses the Large Basin Runoff Model to provide data for the management of water levels in the Great Lakes by estimating United States and Canadian inflows to the Great Lakes from 121 large watersheds. GLERL also simulates streamflows in 34 U.S. watersheds by a grid-based model, the Distributed Large Basin Runoff Model. The NOAA National Weather Service uses the Sacramento Soil Moisture Accounting model to predict flows at river forecast sites. The USACE created or funded the creation of models for at least 30 tributaries to the Great Lakes to better understand sediment erosion, transport, and aggradation processes that affect Federal navigation channels and harbors. Many of the USACE hydrologic models have been coupled with hydrodynamic and sediment-transport models that simulate the processes in the stream and harbor near the mouth of the modeled tributary. Some models either have been applied or have the capability of being applied across the entire Great Lakes Basin; they are (1) the SPAtially Referenced Regressions On Watershed attributes (SPARROW) model, which was developed by the USGS; (2) the High Impact Targeting (HIT) and Digital Watershed models, which were developed by the Institute of Water Research at Michigan State University; (3) the Long-Term Hydrologic Impact Assessment (L–THIA) model, which was developed by researchers at Purdue University; and (4) the Water Erosion Prediction Project (WEPP) model, which was

  4. 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.

  5. Hydrodynamic Modeling of Nokoué Lake in Benin

    Directory of Open Access Journals (Sweden)

    Josué Zandagba

    2016-12-01

    Full Text Available Nokoué Lake is a complex ecosystem, the understanding of which requires control of physical processes that have occurred. For this, the Surface Water Modeling System (SMS hydrodynamic model was calibrated and validated on the water depth data. The results of these simulations show a good match between the simulated and observed data for bottom roughness and turbulent exchange coefficients, of 0.02 m−1/3·s and 20 m2/s respectively. Once the ability of the model to simulate the hydrodynamics of the lake is testified, the model is used to simulate water surface elevation, exchanged flows and velocities. The simulation shows that the tidal amplitude is maximum at the inlet of the channel and decreases gradually from the inlet towards the lagoon’s main body. The propagation of the tidal wave is characterized by the dephasing and the flattening of the amplitude tide, which increases as we move away from the channel. This dephasing is characterized by a high and low tides delay of about 1 or 4 h and also depends on the tide amplitude and location. The velocities inside the lake are very low and do not exceed 0.03 m/s. The highest are obtained at the entrance of the channel. In a flood period, in contrast with the low-water period, incoming flows are higher than outflows, reinforced by the amplitude of the tide. An average renewal time of the lake has been estimated and corresponds during a flood period to 30 days for an average amplitude tide and 26.3 days on a high amplitude tide. In a low water period it is 40.2 days for an average amplitude tide and 30 days for a high amplitude tide. From the results obtained, several measures must be taken into account for the rational management of the lake water resources. These include a dam construction at the lake upstream, to control the river flows, and the dredging of the channel to facilitate exchanges with the sea.

  6. HIGH RESOLUTION MODELLING OF PCB CONGENERS IN LAKE MICHIGAN USING THE LAKE MICHIGAN (LM3) CONTAMINANT MODEL

    Science.gov (United States)

    The Lake Michigan Level 3 (LM3) Model is a numerical model of Lake Michigan used to predict the fate and transport of 54 PCB congeners. The LM3 model segments Lake Michigan horizontally with a 5 x 5 km grid and vertically with 19 sigma layers for a total of 44,042 water column se...

  7. Detecting river sediments to assess hazardous materials at volcanic lake using advanced remote sensing techniques

    Science.gov (United States)

    Saepuloh, Asep; Fitrianingtyas, Chintya

    2016-05-01

    The Toba Caldera formed from large depression of Quaternary volcanism is a remarkable feature at the Earth surface. The last Toba super eruptions were recorded around 73 ka and produced the Youngest Toba Tuff about 2,800 km3. Since then, there is no record of significant volcanic seismicity at Toba Volcanic Complex (TVC). However, the hydrothermal activities are still on going as presented by the existence of hot springs and alteration zones at the northwest caldera. The hydrothermal fluids probably containing some chemical compositions mixed with surficial water pollutant and contaminated the Toba Lake. Therefore, an environmental issues related to the existence of chemical composition and degradation of water clearness in the lake had been raised in the local community. The pollutant sources are debatable between natural and anthropogenic influences because some human activities grow rapidly at and around the lake such as hotels, tourisms, husbandry, aquaculture, as well as urbanization. Therefore, obtaining correct information about the source materials floating at the surface of the Toba Lake is crucial for environmental and hazard mitigation purposes. Overcoming the problem, we presented this paper to assess the source possibility of floating materials at Toba Lake, especially from natural sources such as hydrothermal activities of TVC and river stream sediments. The Spectral Angle Mapper (SAM) techniques using atmospherically corrected of Landsat-8 and colour composite of Polarimetric Synthetic Aperture Radar (PolSAR) were used to map the distribution of floating materials. The seven ground truth points were used to confirm the correctness of proposed method. Based on the SAM and PolSAR techniques, we could detect the interface of hydrothermal fluid at the lake surfaces. Various distributions of stream sediment were also detected from the river mouth to the lake. The influence possibilities of the upwelling process from the bottom floor of Toba Lake were also

  8. History, development and characteristics of lake ecological models

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper provides some introductory information on the history, development, and characteristics of various lake ecosystem models.The modeling of lake ecological processes began to gain importance in the early 1960s. There are a number of models available today, with varying levels of complexity to cope with the variety of environmental problems found in lake environments, e.g. eutrophication, acidification,oxygen depletion, wetland management, heavy metal and pesticide pollution, as well as hydrodynamic problems. In particular, this paper focuses on lake eutrophication and wetland models, as well as addressing strategies appropriate for the design and development of reliable lake ecological models.

  9. Ecosystem element transport model for Lake Eckarfjaerden

    Energy Technology Data Exchange (ETDEWEB)

    Konovalenko, L.; Bradshaw, C. [The Department of Ecology, Environment and Plant Sciences, Stockholm University (Sweden); Andersson, E.; Kautsky, U. [Swedish Nuclear Fuel and Waste Management Co. - SKB (Sweden)

    2014-07-01

    The ecosystem transport model of elements was developed for Lake Eckarfjaerden located in the Forsmark area in Sweden. Forsmark has currently a low level repository (SFR) and a repository for spent fuel is planned. A large number of data collected during site-investigation program 2002-2009 for planning the repository were available for the creation of the compartment model based on carbon circulation, physical and biological processes (e.g. primary production, consumption, respiration). The model is site-specific in the sense that the food web model is adapted to the actual food web at the site, and most estimates of biomass and metabolic rates for the organisms and meteorological data originate from site data. The functional organism groups of Lake Eckarfjaerden were considered as separate compartments: bacterio-plankton, benthic bacteria, macro-algae, phytoplankton, zooplankton, fish, benthic fauna. Two functional groups of bacteria were taken into account for the reason that they have the highest biomass of all functional groups during the winter, comprising 36% of the total biomass. Effects of ecological parameters, such as bacteria and algae biomass, on redistribution of a hypothetical radionuclide release in the lake were examined. The ecosystem model was used to estimate the environmental transfer of several elements (U, Th, Ra) and their isotopes (U-238, U-234,Th-232, Ra-226) to various aquatic organisms in the lake, using element-specific distribution coefficients for suspended particle and sediment. Results of chemical analyses of the water, sediment and biota were used for model validation. The model gives estimates of concentration factors for fish based on modelling rather on in situ measurement, which reduces the uncertainties for many radionuclides with scarce of data. Document available in abstract form only. (authors)

  10. The river model of black holes

    OpenAIRE

    Hamilton, Andrew J. S.; Lisle, Jason P.

    2004-01-01

    This paper presents an under-appreciated way to conceptualize stationary black holes, which we call the river model. The river model is mathematically sound, yet simple enough that the basic picture can be understood by non-experts. %that can by understood by non-experts. In the river model, space itself flows like a river through a flat background, while objects move through the river according to the rules of special relativity. In a spherical black hole, the river of space falls into the b...

  11. Environmental Impact Statement, Aubrey Lake, Elm Fork, Trinity River, Texas.

    Science.gov (United States)

    1973-01-01

    Freshwater fish production has made a substantial contri- bution to human nutrition and to comerce over the years. Although commercial fishing in...of phylum Brachiopoda , characterized by acorn-like shape and looped valves. LACUSTRINE - Of, relating to, or formed in lakes. LIGNITIC - Containing

  12. Assessment of lake sturgeon (Acipenser fulvescens) spawning efforts in the lower St. Clair River, Michigan

    Science.gov (United States)

    Nichols, S. Jerrine; Kennedy, Gregory; Crawford, Eric; Allen, Jeffrey; French, John; Black, Glen; Blouin, Marc; Hickey, James P.; Chernyak, Sergei; Haas, Robert; Thomas, Michael

    2003-01-01

    One of the most threatened remaining populations of lake sturgeon in the Great Lakes is found in the connecting channels between Lake Huron and Lake Erie. Only two spawning grounds are presently known to be active in this region, and both are in the St. Clair River. The spawning reef in the St. Clair River delta has been recently colonized by round gobies (Neogobius melanostomus) in densities up to 25/m2, raising concerns regarding predation on the benthic-oriented eggs and larvae of the sturgeon. Investigations in 1998–1999 showed that while round goby predation does occur, a number of other factors may be equally affecting sturgeon spawning success, including few spawning adults (weeks after hatching, no larvae were found on the reef. We were unable to find them anywhere else in the river, nor was predation on larvae noted in either year. There were factors other than predation affecting larval survival in 1999. There was a higher silt load on the reef than in 1998 and large numbers of dead larvae were found. Recruitment success from this site could be improved by utilizing techniques to increase the number of eggs on the reef, such as reducing the illegal take of adult fish and by placing eggs in predator-exclusion chambers to increase hatch rate.

  13. Water quality of selected fluvial lakes in the context of the Elbe River pollution and anthropogenic activities in the floodplain.

    Science.gov (United States)

    Chalupová, Dagmar; Havlíková, Petra; Janský, Bohumír

    2012-10-01

    The paper evaluates the status of selected fluvial lakes situated in the central part of the Elbe River and the impact of anthropogenic activities including comparison with the Elbe River water quality on them. To achieve the goals of the project, eight researched lakes differed from each other in the intensity of communication with the river, morphometric parameters and in the possibility of anthropogenic contamination (industrial, agricultural and municipal) were chosen. Besides observing the hydrological regime, the research was focused on physical and chemical parameters of water. To sum up, the lakes communicating above ground with the river showed similarities in several parameters, e.g. organic load or conductivity was nearly at the same level, which was lower than in the separated ones. Although the values of nitrates were higher in the river, their content did not reach such concentrations even in the connected lakes because of their more stagnant character. In general, although the Elbe River has a significant effect on water quality of researched lakes, especially in the case of lakes with a restricted communication with the river, their water quality is a result of local conditions, e.g. possibility of contamination by sewage waters, land use in the vicinity, etc.

  14. Cultural Resources Investigation of the Reservoir Shorelines: Gull Lake, Leech Lake, Pine River, and Lake Pokegama. Volume 1,

    Science.gov (United States)

    1979-06-01

    rice lake in Minnesota, Canadian Journal of Botany , 47: 1671-1679. Mason, Philip P., ed. 1958 Schoolcraft Expedition to Lake Itasca. Michigan State...The Pedersen Site (21 LN 2), taught Macalester College and Hamline University combined Field School. 1973- Taught internship students from Macalester...Anthropology with a strong emphasis in Archaeology. -, r’Minor: Botany /Ecology. Bachelor of Arts 1971. Moorhead State University. Major: History

  15. Measuring variability in trophic status in the Lake Waco/Bosque River Watershed.

    Science.gov (United States)

    Rodriguez, Angela D; Matlock, Marty D

    2008-01-11

    Nutrient management in rivers and streams is difficult due to the spatial and temporal variability of algal growth responses. The objectives of this project were to determine the spatial and seasonal in situ variability of trophic status in the Lake Waco/Bosque River watershed, determine the variability in the lotic ecosystem trophic status index (LETSI) at each site as indicators of the system's nutrient sensitivity, and determine if passive diffusion periphytometers could provide threshold algal responses to nutrient enrichment. We used the passive diffusion periphytometer to measure in-situ nutrient limitation and trophic status at eight sites in five streams in the Lake Waco/Bosque River Watershed in north-central Texas from July 1997 through October 1998. The chlorophyll a production in the periphytometers was used as an indicator of baseline chlorophyll a productivity and of maximum primary productivity (MPP) in response to nutrient enrichment (nitrogen and phosphorus). We evaluated the lotic ecosystem trophic status index (LETSI) using the ratio of baseline primary productivity to MPP, and evaluated the trophic class of each site. The rivers and streams in the Lake Waco/Bosque River Watershed exhibited varying degrees of nutrient enrichment over the 18-month sampling period. The North Bosque River at the headwaters (NB-02) located below the Stephenville, Texas wastewater treatment outfall consistently exhibited the highest degree of water quality impact due to nutrient enrichment. Sites at the outlet of the watershed (NB-04 and NB-05) were the next most enriched sites. Trophic class varied for enriched sites over seasons. Seasonality played a significant role in the trophic class and sensitivity of each site to nutrients. Managing rivers and streams for nutrients will require methods for measuring in situ responses and sensitivities to nutrient enrichment. Nutrient enrichment periphytometers show significant potential for use in nutrient gradient studies.

  16. Hydrologic and Geomorphic Changes Resulting from the Onset of Episodic Glacial Lake Outburst Floods: Colonia River, Chile

    Science.gov (United States)

    Jacquet, J.; McCoy, S. W.; McGrath, D.; Nimick, D.; Friesen, B.; Fahey, M. J.; Leidich, J.; Okuinghttons, J.

    2015-12-01

    The Colonia river system, draining the eastern edge of the Northern Patagonia Icefield, Chile, has experienced a dramatic shift in flow regime from one characterized by seasonal discharge variability to one dominated by episodic glacial lake outburst floods (GLOFs). We use multi-temporal visible satellite images, high-resolution digital elevation models (DEMs) derived from stereo image pairs, and in situ observations to quantify sediment and water fluxes out of the dammed glacial lake, Lago Cachet Dos (LC2), as well as the concomitant downstream environmental change. GLOFs initiated in April 2008 and have since occurred, on average, two to three times a year. Differencing concurrent gage measurements made on the Baker River upstream and downstream of the confluence with the Colonia river finds peak GLOF discharges of ~ 3,000 m3s-1, which is ~ 4 times the median discharge of the Baker River and over 20 times the median discharge of the Colonia river. During each GLOF, ~ 200,000,000 m3 of water evacuates from the LC2, resulting in erosion of valley-fill sediments and the delta on the upstream end of LC2. Differencing DEMs between April 2008 and February 2014 revealed that ~ 2.5 x 107 m3 of sediment was eroded. Multi-temporal DEM differencing shows that erosion rates were highest initially, with > 20 vertical m of sediment removed between 2008 and 2012, and generally less than 5 m between 2012 and 2014. The downstream Colonia River Sandur also experienced geomorphic changes due to GLOFs. Using Landsat imagery to calculate the normalized difference water index (NDWI), we demonstrate that the Colonia River was in a stable configuration between 1984 and 2008. At the onset of GLOFs in April 2008, a change in channel location began and continued with each subsequent GLOF. Quantification of sediment and water fluxes due to GLOFs in the Colonia river valley provides insight on the geomorphic and environmental changes in river systems experiencing dramatic shifts in flow

  17. Habitat used by juvenile lake sturgeon (Acipenser fulvescens) in the North Channel of the St. Clair River (Michigan, USA)

    Science.gov (United States)

    Boase, James C.; Manny, Bruce A.; Donald, Katherine A.L.; Kennedy, Gregory W.; Diana, James S.; Thomas, Michael V.; Chiotti, Justin A.

    2014-01-01

    Lake sturgeon (Acipenser fulvescens) occupy the St. Clair River, part of a channel connecting lakes Huron and Erie in the Laurentian Great Lakes. In the North Channel of the St. Clair River, juvenile lake sturgeon (3–7 years old and 582–793 mm in length) were studied to determine movement patterns and habitat usage. Fourteen juveniles were implanted with ultrasonic transmitters and tracked June–August of 2004, 2005 and 2006. Telemetry data, Geographic Information System software, side-scan sonar, video images of the river bottom, scuba diving, and benthic substrate samples were used to determine the extent and composition of habitats they occupied. Juvenile lake sturgeon habitat selection was strongly related to water depth. No fish were found in 700 mm in length selected sand and gravel areas mixed with zebra mussels and areas dominated by zebra mussels, while fish < 700 mm used these habitat types in proportion to their availability.

  18. Assessment of Heavy Metal Pollution in Sediments of Inflow Rivers to Lake Taihu, China.

    Science.gov (United States)

    Niu, Yong; Niu, Yuan; Pang, Yong; Yu, Hui

    2015-11-01

    Lake Taihu, the third-largest freshwater body in China, has many functions, including drinking water supply, flood control, cultivation, navigation, and tourism. In this study, sediment samples were collected at 31 sites from 11 inflow rivers in 2012, to investigate the distribution and concentration of heavy metals copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), and chromium (Cr), and to assess their potential ecological risk. The highest mean concentration was found for Zn, followed by Cu, Cr, Pb, and Ni. Generally, heavy metal pollution was more serious in Wu Jingang River and Caoqiao River, probably because they receive large amounts of wastewater from various local industrial enterprises. The potential ecological risk values of the heavy metals were larger than 120 in more than 25.8% of the sediment samples, indicating a very high risk. The largest ecological risk was due to copper. Furthermore, the results of a principal component analysis and subsequent analysis of variance showed that heavy metal concentrations in the sediment of inflow rivers were higher than those of the lake, which created a large hazard for the aquatic ecosystems of Lake Taihu.

  19. Forming chemical composition of surface waters in the Arctic. Case study of Lake Inari and the River Paz

    Directory of Open Access Journals (Sweden)

    Mazukhina S. I.

    2017-03-01

    Full Text Available Questions of studying the formation of surface and ground waters, their interaction with rocks, development of the basics of their rational use and protection are of great fundamental and practical importance. The influence of the northern Fennoscandian (Baltic Shield rock composition on forming surface waters' chemical composition in the border area of Finland – Russia – Norway (Lake Inari, the River Paz using physical-chemical modeling (Selector software package has been evaluated. For the physical-chemical modeling there have been made two samples of chemical analyses of the most widespread rocks forming the catchment area, with their percentage ratio taken into consideration. Since the catchment area of the prevailing majority of streams feeding Lake Inari is composed of rocks of the Lapland granulite belt (LGB and its framing, it will be the main sample (conditional influence of their composition on the chemical composition of waters is about 80 %. The second sample includes gneisses, migmatites, granite-gneisses, granites and quartz diorites typical for Inari terrane (conventional influence of their composition on the chemical composition of waters is about 20 %. It has been found that the chemical composition of the surface waters is formed by interaction of precipitation with intrusive, metamorphic and sedimentary rocks of northern Fennoskandia containing Clarke concentrations of S, C, F, Zn, Ni, Pb, Cu. It has been shown that due to interactions in the water – rock system the chemical composition of Lake Inari waters as well as upper and middle flow of the River Paz is formed by weathering of granulites of the Lapland granulite belt and Inari terrane granitoids of the northern Fennoscandia. The chemical composition of waters in the River Paz downstream is formed by weathering of metamorphosed volcanic and sedimentary rocks of the Pechenga structure and the impact of industrial pollution

  20. Predicted effects of future climate warming on thermal habitat suitability for Lake Sturgeon (Acipenser fulvescens, Rafinesque, 1817) in rivers in Wisconsin, USA

    Science.gov (United States)

    Lyons, John D.; Stewart, Jana S.

    2015-01-01

    The Lake Sturgeon (Acipenser fulvescens, Rafinesque, 1817) may be threatened by future climate warming. The purpose of this study was to identify river reaches in Wisconsin, USA, where they might be vulnerable to warming water temperatures. In Wisconsin, A. fulvescens is known from 2291 km of large-river habitat that has been fragmented into 48 discrete river-lake networks isolated by impassable dams. Although the exact temperature tolerances are uncertain, water temperatures above 28–30°C are potentially less suitable for this coolwater species. Predictions from 13 downscaled global climate models were input to a lotic water temperature model to estimate amounts of potential thermally less-suitable habitat at present and for 2046–2065. Currently, 341 km (14.9%) of the known habitat are estimated to regularly exceed 28°C for an entire day, but only 6 km (0.3%) to exceed 30°C. In 2046–2065, 685–2164 km (29.9–94.5%) are projected to exceed 28°C and 33–1056 km (1.4–46.1%) to exceed 30°C. Most river-lake networks have cooler segments, large tributaries, or lakes that might provide temporary escape from potentially less suitable temperatures, but 12 short networks in the Lower Fox and Middle Wisconsin rivers totaling 93.6 km are projected to have no potential thermal refugia. One possible adaptation to climate change could be to provide fish passage or translocation so that riverine Lake Sturgeon might have access to more thermally suitable habitats.

  1. River water quality modelling: II

    DEFF Research Database (Denmark)

    Shanahan, P.; Henze, Mogens; Koncsos, L.

    1998-01-01

    The U.S. EPA QUAL2E model is currently the standard for river water quality modelling. While QUAL2E is adequate for the regulatory situation for which it was developed (the U.S. wasteload allocation process), there is a need for a more comprehensive framework for research and teaching. Moreover......, and to achieve robust model calibration. Mass balance problems arise from failure to account for mass in the sediment as well as in the water column and due to the fundamental imprecision of BOD as a state variable. (C) 1998 IAWQ Published by Elsevier Science Ltd. All rights reserved....

  2. CONCENTRATION OF URANIUM IN WATERS OF THE BIGGEST LAKES OF THE TYWA RIVER DRAINAGE BASIN

    Directory of Open Access Journals (Sweden)

    Jacek Kubiak

    2014-07-01

    Full Text Available The paper presents the results of research of uranium concentrations in its different kinds – suspended and dissolved – in waters of the largest lakes located in the catchment area of the River Tywa – Strzeszowskie Lake, Dłużyna Lake, Długie Lake and Dłuzec Lake. Small (or the order of several 0,01 µg/l variations in concentration of uranium in different lakes were noted. The study has also shown a seasonal variation – in a similar range – in concentrations of the above species of uranium, as well as total uranium. The content of dissolved uranium was highest in the autumn and winter, lower in the spring and summer. Overall, total uranium was found in greatest concentrations during the fall, in other seasons concentrations were lower and similar to each other. Suspended uranium was found in largest concentrations in autumn and summer, in lower ones in spring and winter. Concentrations of the different species of uranium during the study period showed a small variation – variation coefficient below 10% for total uranium and dissolved uranium, and about 25% for suspended uranium. The observed concentrations of uranium were typical of uncontaminated unpolluted water.

  3. Sustainable fisheries in shallow lakes: an independent empirical test of the Chinese mitten crab yield model

    Science.gov (United States)

    Wang, Haijun; Liang, Xiaomin; Wang, Hongzhu

    2017-07-01

    Next to excessive nutrient loading, intensive aquaculture is one of the major anthropogenic impacts threatening lake ecosystems. In China, particularly in the shallow lakes of mid-lower Changjiang (Yangtze) River, continuous overstocking of the Chinese mitten crab ( Eriocheir sinensis) could deteriorate water quality and exhaust natural resources. A series of crab yield models and a general optimum-stocking rate model have been established, which seek to benefit both crab culture and the environment. In this research, independent investigations were carried out to evaluate the crab yield models and modify the optimum-stocking model. Low percentage errors (average 47%, median 36%) between observed and calculated crab yields were obtained. Specific values were defined for adult crab body mass (135 g/ind.) and recapture rate (18% and 30% in lakes with submerged macrophyte biomass above and below 1 000 g/m2) to modify the optimum-stocking model. Analysis based on the modified optimum-stocking model indicated that the actual stocking rates in most lakes were much higher than the calculated optimum-stocking rates. This implies that, for most lakes, the current stocking rates should be greatly reduced to maintain healthy lake ecosystems.

  4. Sustainable fisheries in shallow lakes: an independent empirical test of the Chinese mitten crab yield model

    Science.gov (United States)

    Wang, Haijun; Liang, Xiaomin; Wang, Hongzhu

    2016-08-01

    Next to excessive nutrient loading, intensive aquaculture is one of the major anthropogenic impacts threatening lake ecosystems. In China, particularly in the shallow lakes of mid-lower Changjiang (Yangtze) River, continuous overstocking of the Chinese mitten crab (Eriocheir sinensis) could deteriorate water quality and exhaust natural resources. A series of crab yield models and a general optimum-stocking rate model have been established, which seek to benefit both crab culture and the environment. In this research, independent investigations were carried out to evaluate the crab yield models and modify the optimum-stocking model. Low percentage errors (average 47%, median 36%) between observed and calculated crab yields were obtained. Specific values were defined for adult crab body mass (135 g/ind.) and recapture rate (18% and 30% in lakes with submerged macrophyte biomass above and below 1 000 g/m2) to modify the optimum-stocking model. Analysis based on the modified optimum-stocking model indicated that the actual stocking rates in most lakes were much higher than the calculated optimum-stocking rates. This implies that, for most lakes, the current stocking rates should be greatly reduced to maintain healthy lake ecosystems.

  5. A coupled lake-atmosphere model (CLAM) and its application to Lake Kinneret

    Science.gov (United States)

    Pan, Hai

    1999-08-01

    Kinneret is a 166-km2 lake located in Northern Israel, in the central part of the Jordan Valley, a corridor running from north to south, between the Galilee hills in the west and the Golan Heights in the east. Both the Galilee hills and the Golan Heights reach an elevation of about 400 m above mean sea level (MSL), and the lake is about -210 m (MSL). North of the lake is the mountainous area of the Hermon, culminating at about 2800 m (MSL). About 120 km south of it is the Dead Sea, which is about -410 m (MSL), and about 45 km west of it is the Mediterranean Sea. The complexity of the terrain, combined with relatively arid soil and various ground covers surrounding the lake, results in a very complicated system of atmospheric and lake processes. To understand this system, especially the processes affecting the atmosphere and lake dynamics and thermodynamics, and their effects on Lake Kinneret evaporation, a coupled lake-atmosphere model (CLAM) was developed and applied to the lake region. The CLAM is based on the Regional Atmospheric Modeling System (RAMS) and the oceanic S-coordinate Rutgers University Model (SCRUM). Energy, mass, and momentum are conserved at the interface between the atmosphere and the lake, and appropriate balance equations are applied there. In the atmospheric module, two nested grids are employed to simulate Northern Israel at a resolution of 4 x 4 km2, and the near-lake region at a resolution of 1 x 1 km 2. Synoptic conditions obtained from the National Meteorological Center (NMC) reanalysis are assimilated by the model. Soil moisture, which appears to have a significant impact on atmospheric circulation in this region, was transformed from the normalized difference vegetation index (NDVI). Observations collected during two summers above and inside the lake emphasize the good capability of CLAM to simulate surface fluxes and other microclimatic conditions, as well as lake temperature and currents. Although the lake is small (about 12-km wide

  6. Typical freshwater bacteria: an analysis of available 16S rRNA gene sequences from plankton of lakes and rivers

    NARCIS (Netherlands)

    Zwart, G.; Crump, B.C.; Kamst-van Agterveld, M.P.; Hagen, F.; Han, S.K.

    2002-01-01

    In order to identify patterns in bacterial community composition in freshwater habitats, we analyzed the available database of 16S rDNA sequences from freshwater plankton, including 24 new sequences from Parker River (Massachusetts, USA), 42 from Lake Soyang (South Korea) and 148 from Lake IJssel

  7. Hydraulic, geomorphic, and trout habitat conditions of the Lake Fork of the Gunnison River in Hinsdale County, Lake City, Colorado, Water Years 2010-2011

    Science.gov (United States)

    Williams, Cory A.; Richards, Rodney J.; Schaffrath, Keelin R.

    2015-01-01

    Channel rehabilitation, or reconfiguration, to mitigate a variety of riverine problems has become a common practice in the western United States. However, additional work to monitor and assess the channel response to, and the effectiveness of, these modifications over longer periods of time (decadal or longer) is still needed. The Lake Fork of the Gunnison River has been an area of active channel modification to accommodate the needs of the Lake City community since the 1950s. The Lake Fork Valley Conservancy District began a planning process to assess restoration options for a reach of the Lake Fork in Lake City to enhance hydraulic and ecologic characteristics of the reach. Geomorphic channel form is affected by land-use changes within the basin and geologic controls within the reach. The historic channel was defined as a dynamic, braided channel with an active flood plain. This can result in a natural tendency for the channel to braid. A braided channel can affect channel stability of reconfigured reaches when a single-thread meandering channel is imposed on the stream. The U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board and Colorado River Water Conservation District, began a study in 2010 to quantify existing hydraulic and habitat conditions for a reach of the Lake Fork of the Gunnison River in Lake City, Colorado. The purpose of this report is to quantify existing Lake Fork hydraulic and habitat conditions and establish a baseline against which post-reconfiguration conditions can be compared. This report (1) quantifies the existing hydraulic and geomorphic conditions in a 1.1-kilometer section of the Lake Fork at Lake City that has been proposed as a location for future channel-rehabilitation efforts, (2) characterizes the habitat suitability of the reach for two trout species based on physical conditions within the stream, and (3) characterizes the current riparian canopy density.

  8. Assessing sediment dynamics of the Middle St. Johns River Basin, Lake Jesup, Florida, USA

    Science.gov (United States)

    Anderson, W. T.; Nielsen, S. M.; Scinto, L. J.; Thomas, S.; Fugate, D. C.; Corbett, D. R.; Brandt-Williams, S.

    2010-12-01

    Lake Jesup is a shallow, hypereutrophic lake located in the middle St. Johns River basin that received large loads of secondary effluent prior to 1985 and experiences tidal, tributary and wind influenced flow. To date we have assessed the use of several different types of sediment traps at different water depths within this shallow basin (typically less than 2.5 m). Each system deployed has its advantages, but deployments in shallow systems present unique challenges. We have augmented our sediment traps with additional observation and data collection systems to evaluate our approach for studying sedimentation rates in the basin. These systems include a floating barge platform to collect daily water samples for suspended particles, weather stations for wind direction and velocity current (flow) meter and acoustic Doppler water velocity systems (ADVs). Results from 2009 to 2010 show mass accumulation rates ranging between 200 g dw m-2 d-1 to 1200 g dw m-2 d-1. Trap material was analyzed for nutrients to better understand fluxes of carbon, nitrogen, and phosphorus. Sediment oxygen demand was measured during incubation experiments to determine potential effects on water column oxygen concentrations during resuspension events. In the second phase of this project (2010 to 2011) we will measure radioisotopes to better estimate the source of resuspended particles. Our goal is to use the deployed instrumentation to show how hydrodynamics affect sediment transport in this basin. Studying the sediment dynamics of highly productive fresh water end members of estuary systems is critical to better quantify biogeochemical fluxes necessary for effective restoration management. This paper will present a model of nutrient flux and accumulation rates, sediment oxygen demand, correlations between sediment flux and potential driving forces, and initial results from radioisotope sourcing.

  9. Impact of a river system on carbon sedimentation and sequestration in Cook's Bay of Lake Simcoe, Ontario

    Science.gov (United States)

    Blodau, Christian; Agethen, Svenja; Spangenberg, Ines; Broder, Tanja; Gimbel, Nicole; Strauss, Harald; Knorr, Klaus-Holger

    2016-04-01

    The influence of sedimentation rates and organic matter quality on carbon sequestration and mineralization at the land-water interface of lakes is not well understood. To study this issue we investigated shallow Cook's Bay of temperate Lake Simcoe in southern Ontario. The elongated bay provides gradients in morphometry, trophic level, and distance to a major tributary as a potential point source of nutrients and terrestrial organic carbon. At five sampling sites of increasing distance to the river outlet the water column was examined during stratification regarding physio-chemical parameters, dissolved organic matter (DOM) characteristics, sedimentation rates and mineralization of settling material and sediments. To quantify actual organic carbon burial, sedimentation rates and mineralization were determined in situ and by diffusive flux modeling. Long-term carbon burial and sedimentation rates were determined using 210Pb dated sediment cores. Organic carbon quality and origin were analyzed in water samples via fluorescence spectroscopy, solid DOM and settling particles via elemental analysis and 13C isotopic data. Results showed that actual and long-term carbon burial were highest at the central sites of the transect (52-63%) and lowest at the profundal sites (0-25%). Current organic carbon deposition was highest near the river outlet (max. 0.3 g C m-2 d-1) and there the settling material reaching the sediments and in the sediments was also most highly decomposable. Total sedimentation rates and organic carbon burial were closely related. Compared to the outer sites, the DOM quality was significantly different at the site closest to the river outlet but already strongly influenced by lacustrine carbon cycling. Permanent organic carbon burial was mainly influenced by sedimentation related to lake morphometry and dependent parameters. The relation between sedimentation and carbon burial rates underlined the importance of oxygen exposure time and burial for

  10. Modeling Water Quality in Rivers

    Directory of Open Access Journals (Sweden)

    Liren Yu

    2005-01-01

    Full Text Available This study reports a PC software, used in a Windows-based environment, which was developed based on the first order reaction of Biological Oxygen Demand (BOD and a modified Streeter and Phelps equation, in order to simulate and determine the variations of Dissolved Oxygen (DO and of the BOD along with the studied river reaches. The software considers many impacts of environmental factors, such as the different type of discharges (concentrated or punctual source, tributary contribution, distributed source, nitrogenous BOD, BOD sedimentation, photosynthetic production and benthic demand of oxygen, and so on. The software has been used to model the DO profile along one river, with the aim to improve the water quality through suitable engineering measure.

  11. Integrating three lake models into a Phytoplankton Prediction System for Lake Taihu (Taihu PPS) with Python

    NARCIS (Netherlands)

    Huang, J.C.; Gao, J.F.; Hormann, G.; Mooij, W.M.

    2012-01-01

    In the past decade, much work has been done on integrating different lake models using general frameworks to overcome model incompatibilities. However, a framework may not be flexible enough to support applications in different fields. To overcome this problem, we used Python to integrate three lake

  12. Integrating three lake models into a Phytoplankton Prediction System for Lake Taihu (Taihu PPS) with Python

    NARCIS (Netherlands)

    Huang, J.; Gao, J.; Hörmann, G.; Mooij, W.M.

    2012-01-01

    In the past decade, much work has been done on integrating different lake models using general frameworks to overcome model incompatibilities. However, a framework may not be flexible enough to support applications in different fields. To overcome this problem, we used Python to integrate three lake

  13. Radon behavior in springs and wells around Cuitzeo lake, Lerma river basin, Mexico

    OpenAIRE

    Alfaro, R.; V. Martínez; N. Segovia; Peña, P.; M. B. E. López; M. A. Armienta; J. Rangel; Seidel, J.L.

    2002-01-01

    Radon was determined in springs and wells from urban and agricultural zones around Cuitzeo lake, in the Lerma river basin, Mexico. Major and trace elements were also studied in the water samples. The measurement techniques included the liquid scintillation method for 222Rn, conventional chemical analysis for major components and ICP-MS for metallic trace elements. The average radon concentration values were relatively low, ranging from 0.88 to 3.66 Bq L-1 indicating a rapid transit from recha...

  14. Using a Hydrodynamic Lake Model to Predict the Impact of Avalanche Events at Lake Palcacocha, Peru

    Science.gov (United States)

    Chisolm, R. E.; Somos-Valenzuela, M. A.; McKinney, D. C.; Hodges, B. R.

    2013-12-01

    Accelerated retreat of Andean glaciers in recent decades due to a warming climate has caused the emergence and growth of glacial lakes. As these lakes continue to grow, they pose an increasing risk of glacial lake outburst floods (GLOFs). GLOFs can be triggered by moraine failures or by avalanches, rockslides, or ice calving into glacial lakes. Many of the processes influencing GLOF risk are still poorly understood. For many decades Lake Palcacocha in the Cordillera Blanca, Peru has posed a threat to citizens living in the watershed below, including the city of Huaraz which was devastated by a GLOF in 1941. A safety system for Lake Palcacocha was put in place in the 1970's to control the lake level with a tunnel and reinforced dyke, but the lake has since grown to the point where the lake is once again dangerous. Overhanging ice from the Palcaraju glacier and a relatively low freeboard level make the lake vulnerable to avalanches and landslides. A siphon system has been put in place to lower the lake below the level of the tunnel, but this system is temporary and the potential reduction in the water level is limited. Lake Palcacocha is used as a case study to investigate the impact of an avalanche event on the lake dynamics and the ensuing flood hydrograph. Empirical equations are used to determine the initial wave characteristics of an impulse wave created by three different avalanche scenarios that represent small, medium and large events. The characteristics of the initial impulse wave are used as inputs to a three-dimensional hydrodynamic model to predict the wave propagation across the lake and the moraine overtopping volume. The results from this model will be used as inputs to a downstream GLOF model to predict the impact from an outburst flood event. Additionally several scenarios are considered to evaluate the downstream impact from avalanche events with a reduction in the lake level. Use of a robust three-dimensional hydrodynamic lake model enables more

  15. The Fox River PCB transport study: Stepping stone to a healthy Great Lakes ecosystem

    Science.gov (United States)

    Fitzgerald, Sharon A.; Steuer, Jeffrey J.

    1996-01-01

    Polychlorinated Biphenyls (PCBs) in the Great Lakes Despite being banned since the 1970's, polychlorinated biphenyls (PCBs) continue to pose a threat to the environment because of their persistence and toxicity to organisms ranging from minute algae to fish, waterfowl, and human beings. PCBs, a set of 209 related chlorinated organic compounds, had various industrial uses such as in hydraulic fluids, cutting oils, sealants, and pesticides. Despite the manufacturing ban in the mid-1970's, PCBs remain ubiquitous in the environment. In the Laurentian Great Lakes of the Midwest. PCBs and other toxic compounds contaminate bottom sediments at almost all designated "areas of concern" (AOC)(figure 1, upper left inset). The International Joint Commission, a binational group from Canada and the United States, has identified these AOCs in their efforts to restore and protect Great Lakes ecosystems. One such area, the Fox River which flows into Green Bay, has been the focus of much scientific study in an effort to improve not only that river but to apply lessons learned to other AOCs. The final goal is a healthy Great Lakes food chain with fish and waterfowl that are safe to consume.

  16. Modeling water quality, temperature, and flow in Link River, south-central Oregon

    Science.gov (United States)

    Sullivan, Annett B.; Rounds, Stewart A.

    2016-09-09

    The 2.1-km (1.3-mi) Link River connects Upper Klamath Lake to the Klamath River in south-central Oregon. A CE-QUAL-W2 flow and water-quality model of Link River was developed to provide a connection between an existing model of the upper Klamath River and any existing or future models of Upper Klamath Lake. Water-quality sampling at six locations in Link River was done during 2013–15 to support model development and to provide a better understanding of instream biogeochemical processes. The short reach and high velocities in Link River resulted in fast travel times and limited water-quality transformations, except for dissolved oxygen. Reaeration through the reach, especially at the falls in Link River, was particularly important in moderating dissolved oxygen concentrations that at times entered the reach at Link River Dam with marked supersaturation or subsaturation. This reaeration resulted in concentrations closer to saturation downstream at the mouth of Link River.

  17. Sediment mobility and bed armoring in the St Clair River: insights from hydrodynamic modeling

    Science.gov (United States)

    Liu, Xiaofeng; Parker, Gary; Czuba, Jonathan A.; Oberg, Kevin; Mier, Jose M.; Best, James L.; Parsons, Daniel R.; Ashmore, Peter; Krishnappan, Bommanna G.; Garcia, Marcelo H.

    2012-01-01

    The lake levels in Lake Michigan-Huron have recently fallen to near historical lows, as has the elevation difference between Lake Michigan-Huron compared to Lake Erie. This decline in lake levels has the potential to cause detrimental impacts on the lake ecosystems, together with social and economic impacts on communities in the entire Great Lakes region. Results from past work suggest that morphological changes in the St Clair River, which is the only natural outlet for Lake Michigan-Huron, could be an appreciable factor in the recent trends of lake level decline. A key research question is whether bed erosion within the river has caused an increase in water conveyance, therefore, contributed to the falling lake level. In this paper, a numerical modeling approach with field data is used to investigate the possibility of sediment movement in the St Clair River and assess the likelihood of morphological change under the current flow regime. A two-dimensional numerical model was used to study flow structure, bed shear stress, and sediment mobility/armoring over a range of flow discharges. Boundary conditions for the numerical model were provided by detailed field measurements that included high-resolution bathymetry and three-dimensional flow velocities. The results indicate that, without considering other effects, under the current range of flow conditions, the shear stresses produced by the river flow are too low to transport most of the coarse bed sediment within the reach and are too low to cause substantial bed erosion or bed scour. However, the detailed maps of the bed show mobile bedforms in the upper St Clair River that are indicative of sediment transport. Relatively high shear stresses near a constriction at the upstream end of the river and at channel bends could cause local scour and deposition. Ship-induced propeller wake erosion also is a likely cause of sediment movement in the entire reach. Other factors that may promote sediment movement, such as ice

  18. Satellite radar altimetry for monitoring small river and lakes in Indonesia

    Directory of Open Access Journals (Sweden)

    Y. B. Sulistioadi

    2014-03-01

    Full Text Available Remote sensing and satellite geodetic observations are capable for hydrologic monitoring of freshwater resources. For the case of satellite radar altimetry, limited temporal resolutions (e.g., satellite revisit period prohibit the use of this method for a short ( To address this scientific challenge, this study tries to monitor small (40–200 m width and medium-sized (200–800 m width rivers and lakes using satellite altimetry through identification and choice of the over-water radar waveforms corresponding to the appropriately waveform-retracked water level. This study addresses the humid tropics of Southeast Asia, specifically in Indonesia, where similar studies do not yet exist and makes use Level 2 radar altimeter measurements generated by European Space Agency's (ESA's Envisat (Environmental Satellite mission. This experiment proves that satellite altimetry provides a good alternative, or the only means in some regions, to measure the water level of medium-sized river (200–800 m width and small lake (extent 2 in Southeast Asia humid tropic with reasonable accuracy. In addition, the procedure to choose retracked Envisat altimetry water level heights via identification or selection of standard waveform shapes for inland water is recommended and should be a standard measure especially over small rivers and lakes. This study also found that Ice-1 is not necessarily the best retracker as reported by previous studies, among the four standard waveform retracking algorithms for Envisat radar altimetry observing inland water bodies.

  19. 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

  20. Lake Diefenbaker: Water Quality Assessment and Modeling for Management under Environmental Change

    Science.gov (United States)

    Sereda, J.; Wheater, H. S.; Hudson, J.; Doig, L.; Liber, K.; Jones, P.; Giesy, J.; Bharadwaj, L.

    2011-12-01

    Preliminary results are presented for a comprehensive inter-disciplinary study on Lake Diefenbaker initiated by the Global Institute for Water Security to understand the physical and biogeochemical processes affecting water quality under climate change and their policy implications. Lake Diefenbaker is a large reservoir (surface area ~500km2 and Zmean ~33m) located in Southern Saskatchewan, Canada and is a critically-important water resource for Saskatchewan. It receives nearly all of its flow from the South Saskatchewan River, which flows through some of the most urbanized and intense agricultural lands of southern Alberta. As a result these waters contain high levels of nutrients [nitrogen (N) and phosphorus (P)] along with a variety of chemical contaminants characteristic of anthropogenic activity. In addition, riparian and in-lake activities provide local sources of nutrients, from domestic sewage, agriculture and fish farming. The South Saskatchewan River has been identified by the World Wildlife Fund (2009) as Canada's most threatened river in terms of environmental flow. Lake Diefenbaker has numerous large deep embayments (depth >20m) and an annual water level fluctuation of ~6m. A deep thermocline (~25m) forms infrequently. Stratification does not occur throughout the lake. Anecdotal information suggests that the frequency and severity of algal blooms are increasing; although blooms have been sporadic and localized. This localized eutrophication may be related to local stratification patterns, point source nutrient loading, and/or internal lake processes (i.e., internal nutrient loading). A paleolimnological reconstruction has begun to assess historical nutrient and contaminant loading to Lake Diefenbaker and hence the trajectory of water quality in the lake. Major point sources and diffuse sources of N and P are also under investigation. In addition, the type (N versus P) and degree of nutrient limitation of bacteria and algae are being assessed (spatially

  1. 75 FR 26094 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-05-11

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River, and Calumet-Saganashkee Channel...: The Coast Guard is establishing a temporary safety zone from Brandon Road Lock and Dam to...

  2. New Challcngcs and Opportunitics for Flood Control in the Huai Rivcr: Addressing a Changing River-Lake Relationship

    Institute of Scientific and Technical Information of China (English)

    ZHANG Min; XIA Jun; HONG Cheng

    2012-01-01

    This paper addresses the change of the river-lake relationship in the Huai River and its causes due to environmental change and human activities. A preliminary analysis is made from three aspects: (1) the natural geographical change particularly captured by the Yellow River, (2) water conservancy project construction, and (3) socioeconomic development in the Huai River Basin. Key problems of changes in this river-lake relationship and the Huai River flood control are tackled, involving flood control and disaster alleviation ability of the Basin, engineering and non-engineering measurements applied to flood control and disaster mitigation, and water governance for adaptive management. Research shows that the Huai River is a rather complex one due to its complex geography with a hybrid wet and dry climate zoon, and higher population density. With the alternation of the river-lake relationship and socioeconomic development in the region, new problems keep arising, imposing new requirements on its sustainable water management. Thus, understanding the Huai River is a long and gradually improving process, its future planning should keep absorbing new achievements of science and technology development, employing new technologies and methods, and gradually deepening our understanding of its fundamental principles. Water governance and adaptive water management will be new challenges and opportunities for the Basin in its river system change and flood control.

  3. Groundwater quality in the Chemung River, Eastern Lake Ontario, and Lower Hudson River Basins, New York, 2013

    Science.gov (United States)

    Scott, Tia-Marie; Nystrom, Elizabeth A.; Reddy, James E.

    2015-11-10

    In a study conducted by the U.S. Geological Survey (USGS) in cooperation with the New York State Department of Environmental Conservation, water samples were collected from 4 production wells and 4 domestic wells in the Chemung River Basin, 8 production wells and 7 domestic wells in the Eastern Lake Ontario Basin, and 12 production wells and 13 domestic wells in the Lower Hudson River Basin (south of the Federal Lock and Dam at Troy) in New York. All samples were collected in June, July, and August 2013 to characterize groundwater quality in these basins. The samples were collected and processed using standard USGS procedures and were analyzed for 148 physiochemical properties and constituents, including dissolved gases, major ions, nutrients, trace elements, pesticides, volatile organic compounds, radionuclides, and indicator bacteria.

  4. Late Pleistocene outburst flooding from pluvial Lake Alvord into the Owyhee River, Oregon

    Science.gov (United States)

    Carter, Deron T.; Ely, Lisa L.; O'Connor, Jim E.; Fenton, Cassandra R.

    2006-05-01

    At least one large, late Pleistocene flood traveled into the Owyhee River as a result of a rise and subsequent outburst from pluvial Lake Alvord in southeastern Oregon. Lake Alvord breached Big Sand Gap in its eastern rim after reaching an elevation of 1292 m, releasing 11.3 km 3 of water into the adjacent Coyote Basin as it eroded the Big Sand Gap outlet channel to an elevation of about 1280 m. The outflow filled and then spilled out of Coyote Basin through two outlets at 1278 m and into Crooked Creek drainage, ultimately flowing into the Owyhee and Snake Rivers. Along Crooked Creek, the resulting flood eroded canyons, stripped bedrock surfaces, and deposited numerous boulder bars containing imbricated clasts up to 4.1 m in diameter, some of which are located over 30 m above the present-day channel. Critical depth calculations at Big Sand Gap show that maximum outflow from a 1292- to 1280-m drop in Lake Alvord was ˜ 10,000 m 3 s - 1 . Flooding became confined to a single channel approximately 40 km downstream of Big Sand Gap, where step-backwater calculations show that a much larger peak discharge of 40,000 m 3 s - 1 is required to match the highest geologic evidence of the flood in this channel. This inconsistency can be explained by (1) a single 10,000 m 3 s - 1 flood that caused at least 13 m of vertical incision in the channel (hence enlarging the channel cross-section); (2) multiple floods of 10,000 m 3 s - 1 or less, each producing some incision of the channel; or (3) an earlier flood of 40,000 m 3 s - 1 creating the highest flood deposits and crossed drainage divides observed along Crooked Creek drainage, followed by a later 10,000 m 3 s - 1 flood associated with the most recent shorelines in Alvord and Coyote Basins. Well-developed shorelines of Lake Alvord at 1280 m and in Coyote Basin at 1278 m suggest that after the initial flood, postflood overflow persisted for an extended period, connecting Alvord and Coyote Basins with the Owyhee River of the

  5. Simulated tritium concentrations in river waters of the western Lake Taupo catchment, New Zealand with MODPATH particle tracking

    Directory of Open Access Journals (Sweden)

    M. A. Gusyev

    2014-03-01

    Full Text Available We simulated in a previous study tritium concentrations in the river waters of the western Lake Taupo catchment (WLTC using MODFLOW/MT3DMS model (Gusyev et al., 2013. The model was calibrated to match simulated tritium to measured tritium in river waters at baseflows of the Waihaha, Whanganui, Whareroa, Kuratau and Omori river catchments of the WLTC. Following from this work we now utilized the same MODFLOW model for the WLTC to calculate the pathways of groundwater particles (and their corresponding tritium concentrations using steady-state particle tracking with MODPATH. In order to simulate baseflow tritium concentrations with MODPATH, transit time distributions (TTDs such as cumulative frequency distribution (CFD and probability density function (PDF are generated with particle tracking for the river networks of the five WLTC catchment outflows. Then, PDFs are used in the convolution integral with tritium concentration time series obtained in the precipitation. The resulting MODPATH tritium concentrations yield a very good match to measured tritium concentrations and are similar to the MT3DMS simulated tritium concentrations, with the greatest variation occurring around the bomb peak. MODPATH and MT3DMS also yield similar Mean Transit Times (MTT of groundwater contribution to river baseflows, but the actual shape of the TTDs is strikingly different. While both distributions provide valuable information, the methodologies used to derive the TTDs are fundamentally different and hence must be interpreted differently. With the current models setting, only the methodology used with MODPATH provides the true TTD for use with the convolution integral.

  6. Estimation of lake water - groundwater interactions in meromictic mining lakes by modelling isotope signatures of lake water.

    Science.gov (United States)

    Seebach, Anne; Dietz, Severine; Lessmann, Dieter; Knoeller, Kay

    2008-03-01

    A method is presented to assess lake water-groundwater interactions by modelling isotope signatures of lake water using meteorological parameters and field data. The modelling of delta(18)O and deltaD variations offers information about the groundwater influx into a meromictic Lusatian mining lake. Therefore, a water balance model is combined with an isotope water balance model to estimate analogies between simulated and measured isotope signatures within the lake water body. The model is operated with different evaporation rates to predict delta(18)O and deltaD values in a lake that is only controlled by weather conditions with neither groundwater inflow nor outflow. Comparisons between modelled and measured isotope values show whether the lake is fed by the groundwater or not. Furthermore, our investigations show that an adaptation of the Craig and Gordon model [H. Craig, L.I. Gordon. Deuterium and oxygen-18 variations in the ocean and the marine atmosphere. In Stable Isotopes in Oceanographic Studies and Paleotemperature, Spoleto, E. Tongiorgi (Ed.), pp. 9-130, Consiglio Nazionale delle Ricerche, Laboratorio di Geologia Nucleare, Pisa (1965).] to specific conditions in temperate regions seems necessary.

  7. Geochemical monitoring of volcanic lakes. A generalized box model for active crater lakes

    Directory of Open Access Journals (Sweden)

    Franco Tassi

    2011-06-01

    Full Text Available

    In the past, variations in the chemical contents (SO42−, Cl−, cations of crater lake water have not systematically demonstrated any relationships with eruptive activity. Intensive parameters (i.e., concentrations, temperature, pH, salinity should be converted into extensive parameters (i.e., fluxes, changes with time of mass and solutes, taking into account all the internal and external chemical–physical factors that affect the crater lake system. This study presents a generalized box model approach that can be useful for geochemical monitoring of active crater lakes, as highly dynamic natural systems. The mass budget of a lake is based on observations of physical variations over a certain period of time: lake volume (level, surface area, lake water temperature, meteorological precipitation, air humidity, wind velocity, input of spring water, and overflow of the lake. This first approach leads to quantification of the input and output fluxes that contribute to the actual crater lake volume. Estimating the input flux of the "volcanic" fluid (Qf- kg/s –– an unmeasurable subsurface parameter –– and tracing its variations with time is the major focus during crater lake monitoring. Through expanding the mass budget into an isotope and chemical budget of the lake, the box model helps to qualitatively characterize the fluids involved. The (calculated Cl− content and dD ratio of the rising "volcanic" fluid defines its origin. With reference to continuous monitoring of crater lakes, the present study provides tips that allow better calculation of Qf in the future. At present, this study offers the most comprehensive and up-to-date literature review on active crater lakes.

  8. The river model of black holes

    CERN Document Server

    Hamilton, A J S; Hamilton, Andrew J. S.; Lisle, Jason P.

    2004-01-01

    This paper presents a new way to conceptualize stationary black holes, which we call the river model. The river model is mathematically sound, yet simple enough that the basic picture can be understood by non-experts. In the river model, space itself flows like a river through a flat background, while objects move through the river according to the rules of special relativity. In a spherical black hole, the river of space falls into the black hole at the Newtonian escape velocity, hitting the speed of light at the horizon. Inside the horizon, the river flows inward faster than light, carrying everything with it. We show that the river model works also for rotating (Kerr-Newman) black holes, though with a surprising twist. As in the spherical case, the river of space can be regarded as moving through a flat background. However, the river does not spiral inward, as one might have anticipated, but rather falls inward with no azimuthal swirl at all. Instead, the river has at each point not only a velocity but als...

  9. Incorporation of Fine-Grained Sediment Erodibility Measurements into Sediment Transport Modeling, Capitol Lake, Washington

    Science.gov (United States)

    Stevens, Andrew W.; Gelfenbaum, Guy; Elias, Edwin; Jones, Craig

    2008-01-01

    Capitol Lake was created in 1951 with the construction of a concrete dam and control gate that prevented salt-water intrusion into the newly formed lake and regulated flow of the Deschutes River into southern Puget Sound. Physical processes associated with the former tidally dominated estuary were altered, and the dam structure itself likely caused an increase in retention of sediment flowing into the lake from the Deschutes River. Several efforts to manage sediment accumulation in the lake, including dredging and the construction of sediment traps upriver, failed to stop the lake from filling with sediment. The Deschutes Estuary Feasibility Study (DEFS) was carried out to evaluate the possibility of removing the dam and restoring estuarine processes as an alternative ongoing lake management. An important component of DEFS was the creation of a hydrodynamic and sediment transport model of the restored Deschutes Estuary. Results from model simulations indicated that estuarine processes would be restored under each of four restoration alternatives, and that over time, the restored estuary would have morphological features similar to the predam estuary. The model also predicted that after dam-removal, a large portion of the sediment eroded from the lake bottom would be deposited near the Port of Olympia and a marina located in lower Budd Inlet seaward of the present dam. The volume of sediment transported downstream was a critical piece of information that managers needed to estimate the total cost of the proposed restoration project. However, the ability of the model to predict the magnitude of sediment transport in general and, in particular, the volume of sediment deposition in the port and marina was limited by a lack of information on the erodibility of fine-grained sediments in Capitol Lake. Cores at several sites throughout Capitol Lake were collected between October 31 and November 1, 2007. The erodibility of sediments in the cores was later determined in the

  10. Mesoscale modeling of lake effect snow over Lake Erie - sensitivity to convection, microphysics and the water temperature

    NARCIS (Netherlands)

    Theeuwes, N.E.; Steeneveld, G.J.; Krikken, F.; Holtslag, A.A.M.

    2010-01-01

    Lake effect snow is a shallow convection phenomenon during cold air advection over a relatively warm lake. A severe case of lake effect snow over Lake Erie on 24 December 2001 was studied with the MM5 and WRF mesoscale models. This particular case provided over 200 cm of snow in Buffalo (NY), caused

  11. Modeling water quality effects of structural and operational changes to Scoggins Dam and Henry Hagg Lake, Oregon

    Science.gov (United States)

    Sullivan, Annett B.; Rounds, Stewart A.

    2006-01-01

    To meet water quality targets and the municipal and industrial water needs of a growing population in the Tualatin River Basin in northwestern Oregon, an expansion of Henry Hagg Lake is under consideration. Hagg Lake is the basin's primary storage reservoir and provides water during western Oregon's typically dry summers. Potential modifications include raising the dam height by 6.1 meters (20 feet), 7.6 meters (25 feet), or 12.2 meters (40 feet); installing additional outlets (possibly including a selective withdrawal tower); and adding additional inflows to provide greater reliability of filling the enlarged reservoir. One method of providing additional inflows is to route water from the upper Tualatin River through a tunnel and into Sain Creek, a tributary to the lake. Another option is to pump water from the Tualatin River (downstream of the lake) uphill and into the reservoir during the winter--the 'pump-back' option. A calibrated CE-QUAL-W2 model of Henry Hagg Lake's hydrodynamics, temperature, and water quality was used to examine the effect of these proposed changes on water quality in the lake and downstream. Most model scenarios were run with the calibrated model for 2002, a typical water year; a few scenarios were run for 2001, a drought year. More...

  12. Using radar altimetry to update a routing model of the Zambezi River Basin

    DEFF Research Database (Denmark)

    Michailovsky, Claire Irene B.; Bauer-Gottwein, Peter

    2012-01-01

    Satellite radar altimetry allows for the global monitoring of lakes and river levels. However, the widespread use of altimetry for hydrological studies is limited by the coarse temporal and spatial resolution provided by current altimetric missions and the fact that discharge rather than level...... is needed for hydrological applications. To overcome these limitations, altimetry river levels can be combined with hydrological modeling in a dataassimilation framework. This study focuses on the updating of a river routing model of the Zambezi using river levels from radar altimetry. A hydrological model...... of the basin was built to simulate the land phase of the water cycle and produce inflows to a Muskingum routing model. River altimetry from the ENVISAT mission was then used to update the storages in the reaches of the Muskingum model using the Extended Kalman Filter. The method showed improvements in modeled...

  13. Glacial lake outburst flood risk assessment using combined approaches of remote sensing, GIS and dam break modelling

    Directory of Open Access Journals (Sweden)

    Arpit Aggarwal

    2016-01-01

    Full Text Available A great number of glacial lakes have appeared in many mountain regions across the world during the last half-century due to receding of glaciers and global warming. In the present study, glacial lake outburst flood (GLOF risk assessment has been carried out in the Teesta river basin located in the Sikkim state of India. First, the study focuses on accurate mapping of the glaciers and glacial lakes using multispectral satellite images of Landsat and Indian Remote Sensing satellites. For glacier mapping, normalized difference snow index (NDSI image and slope map of the area have been utilized. NDSI approach can identify glaciers covered with clean snow but debris-covered glaciers cannot be mapped using NDSI method alone. For the present study, slope map has been utilized along with the NDSI approach to delineate glaciers manually. Glacial lakes have been mapped by supervised maximum likelihood classification and normalized difference water index followed by manual editing afterwards using Google Earth images. Second, the first proper inventory of glacial lakes for Teesta basin has been compiled containing information of 143 glacial lakes. Third, analysis of these lakes has been carried out for identification of potentially dangerous lakes. Vulnerable lakes have been identified on the basis of parameters like surface area, position with respect to parent glacier, growth since 2009, slope, distance from the outlet of the basin, presence of supraglacial lakes, presence of other lakes in downstream, condition of moraine, condition of the terrain around them, etc. From these criterions, in total, 18 lakes have been identified as potentially dangerous glacial lakes. Out of these 18 lakes, further analysis has been carried out for the identification of the most vulnerable lake. Lake 140 comes out to be the most vulnerable for a GLOF event. Lastly, for this potentially dangerous lake, different dam break parameters have been generated using satellite data

  14. 3-D Eutrophication Modeling for Lake Simcoe, Canada

    Science.gov (United States)

    Lu, Q.; Duckett, F.; Nairn, R.; Brunton, A.

    2006-12-01

    The Lake Simcoe Region Conservation Authority (LSRCA) and the Province of Ontario are undertaking a series of studies to facilitate management of the pressures of population growth in the Lake Simcoe watershed. With rapid population growth and urban development comes additional land clearing, storm water runoff and the discharge of treated sewage, all of which are sources of increased phosphorus loading to Lake Simcoe. Depressed oxygen levels were linked to phosphorous enrichment of the lake, with the resultant stimulation of algal growth in the sunlit upper waters of the lake, and its subsequent senescence and settling into the hypolimnion where bacterial decomposition consumes oxygen from the stratified waters. This poster describes a 3-D hydrodynamic, thermal and water quality model of Lake Simcoe developed using the Danish Hydraulics Institute (DHI) MIKE3 model. The hydrodynamic module includes wind-driven circulation, temperature variation, development of the thermocline and thermal stratification, and hydraulic forcing from inflowing tributaries. This is linked to the water quality module which simulates the eutrophication processes in the response of the lake to loadings of phosphorus, such as algal growth, the growth of aquatic plants and subsequent oxygen consumption. The model has been calibrated against Acoustic Doppler Current Profiler velocity data, plus measured temperature and water quality data at MOE stations in the lake and water intakes. The model is an important assessment tool for the management of the lake and its watersheds, allowing assessment of the impacts of the urban growth and land use change on the water quality in Lake Simcoe.

  15. Sulfur and strontium isotope geochemistry of tributary rivers of Lake Biwa: implications for human impact on the decadal change of lake water quality.

    Science.gov (United States)

    Nakano, Takanori; Tayasu, Ichiro; Wada, Eitaro; Igeta, Akitake; Hyodo, Fujio; Miura, Yuuta

    2005-06-01

    To study the deterioration of the water quality in Lake Biwa, Japan, over the last 40 years, we measured the concentrations and isotopic ratios of sulfur and strontium of water in 41 inflowing rivers and one discharging river. The concentrations of SO4 and Sr of inflowing rivers at downstream sites were generally high in the southern urban area and in the eastern area, where a large agricultural plain is situated, but low in the northern and western areas, whose watersheds are mountainous and with low population density. SO4 and Sr concentrations are also lower at upstream sites, which are closer to mountainous areas. Thus, the inflowing river receives large amounts of SO4 and Sr as it flows across the plain, where human activity levels are high. The delta34S or 87Sr/86Sr values of most eastern rivers at downstream sites are lower than those of water in Lake Biwa, and values become more uniform as the proportion of the plain area in the watershed increases. River water in other areas has higher values of delta34S or 87Sr/86Sr than the lake water. This result indicates that the decadal decrease of delta34S and 87Sr/86Sr in the lake water has been caused mainly by the increased flux of SO4 and Sr from rivers in the eastern plain. We assume that in the plain, sulfur, nitrogen, and organic compounds induced by human activities generate sulfuric, nitric, and organic acids in the water, which accelerate the extraction of Sr from bedrocks, leading to the generation of Sr in the river water in the area.

  16. A National Wildlife Refuge Proposal : Proposed Establishment of a National Wildlife Refuge at the Confluence of the Red and Red Lake Rivers of North Dakota and Minnesota

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Red River Valley experienced catastrophic flooding in April of 1997 from the Red and Red Lake Rivers, and Congressional delegations and the U.S. Army Corps of...

  17. Hydrology and management of Lakes Mead and Mohave within the Colorado River Basin: Chapter 3 in A synthesis of aquatic science for management of Lakes Mead and Mohave

    Science.gov (United States)

    Holdren, G. Chris; Tietjen, Todd; Turner, Kent; Miller, Jennell M.

    2012-01-01

    The Colorado River Basin covers parts of seven States: Colorado, Wyoming, Utah, New Mexico, Nevada, Arizona, and California; at 1,450 mi (2,333.5 km) in length, the Colorado River is the seventh longest river in the United States (fig. 3-1). The Bureau of Reclamation has the responsibility for management of this system, in coordination with the seven basin States, within a complex framework of law, regulations, compact, treaty, and policies often referred to collectively as the “Law of the River.” Lake Mead is a critical component of the overall Colorado River management, providing the capacity to store almost 2 years of the average runoff of the river.

  18. Sources of suspended-sediment loads in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary, south Texas, 1958–2010

    Science.gov (United States)

    Ockerman, Darwin J.; Heitmuller, Franklin T.; Wehmeyer, Loren L.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers, Fort Worth District; City of Corpus Christi; Guadalupe-Blanco River Authority; San Antonio River Authority; and San Antonio Water System, developed, calibrated, and tested a Hydrological Simulation Program-FORTRAN (HSPF) watershed model to simulate streamflow and suspended-sediment concentrations and loads during 1958-2010 in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary in south Texas. Data available to simulate suspended-sediment concentrations and loads consisted of historical sediment data collected during 1942-82 in the study area and suspended-sediment concentration data collected periodically by the USGS during 2006-7 and 2010 at three USGS streamflow-gaging stations (08211000 Nueces River near Mathis, Tex. [the Mathis gage], 08211200 Nueces River at Bluntzer, Tex. [the Bluntzer gage], and 08211500 Nueces River at Calallen, Tex. [the Calallen gage]), and at one ungaged location on a Nueces River tributary (USGS station 08211050 Bayou Creek at Farm Road 666 near Mathis, Tex.). The Mathis gage is downstream from Wesley E. Seale Dam, which was completed in 1958 to impound Lake Corpus Christi. Suspended-sediment data collected before and after completion of Wesley E. Seale Dam provide insights to the effects of the dam and reservoir on suspended-sediment loads transported by the lower Nueces River downstream from the dam to the Nueces Estuary. Annual suspended-sediment loads at the Nueces River near the Mathis, Tex., gage were considerably lower for a given annual mean discharge after the dam was completed than before the dam was completed.

  19. The use of invertebrates as indicators of environmental change in alpine rivers and lakes

    Energy Technology Data Exchange (ETDEWEB)

    Khamis, K.; Hannah, D.M. [School of Geography Earth and Environmental Science, University of Birmingham, Birmingham B15 2TT (United Kingdom); Brown, L.E. [School of Geography/water@leeds, University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom); Tiberti, R. [DSTA, Dipartimento di Scienze della Terra e dell' Ambiente, University of Pavia, Via Ferrata 9, 27100 Pavia (Italy); Alpine Wildlife Research Centre, Gran Paradiso National Park, Degioz 11, I-1101 Valsavarenche, Aosta (Italy); Milner, A.M., E-mail: a.m.milner@bham.ac.uk [School of Geography Earth and Environmental Science, University of Birmingham, Birmingham B15 2TT (United Kingdom); Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775 (United States)

    2014-09-15

    In alpine regions climatic change will alter the balance between water sources (rainfall, ice-melt, snowmelt, and groundwater) for aquatic systems, particularly modifying the relative contributions of meltwater, groundwater and rain to both rivers and lakes. While these changes are expected to have implications for alpine aquatic ecosystems, little is known about potential ecological tipping points and associated indicator taxa. We examined changes in biotic communities along a gradient of glacier influence for two study systems: (1) a stream network in the French Pyrénées; and (2) a network of lakes in the Italian Alps, with the aim of identifying potential indicator taxa (macroinvertebrates and zooplankton) of glacier retreat in these environments. To assess parallels in biotic responses across streams and lakes, both primary data and findings from other publications were synthesised. Using TITAN (Threshold Indicator Taxa ANalysis) changes in community composition of river taxa were identified at thresholds of < 5.1% glacier cover and < 66.6% meltwater contribution. Below these thresholds the loss of cold stenothermic benthic invertebrate taxa, Diamesa spp. and the Pyrenean endemic Rhyacophila angelieri was apparent. Some generalist taxa including Protonemura sp., Perla grandis, Baetis alpinus, Rhithrogena loyolaea and Microspectra sp. increased when glacier cover was < 2.7% and < 52% meltwater. Patterns were not as distinct for the alpine lakes, due to fewer sampling sites; however, Daphnia longispina grp. and the benthic invertebrate groups Plectopera and Planaria were identified as potential indicator taxa. While further work is required to assess potential indicator taxa for alpine lake systems, findings from alpine river systems were consistent between methods for assessing glacier influence (meltwater contribution/glacier cover). Hence, it is clear that TITAN could become a useful management tool, enabling: (i) the identification of taxa particularly

  20. Groundwater quality in the Lake Champlain and Susquehanna River basins, New York, 2014

    Science.gov (United States)

    Scott, Tia-Marie; Nystrom, Elizabeth A.; Reddy, James E.

    2016-11-04

    In a study conducted by the U.S. Geological Survey in cooperation with the New York State Department of Environmental Conservation, groundwater samples were collected from 6 production wells and 7 domestic wells in the Lake Champlain Basin and from 11 production wells and 9 domestic wells in the Susquehanna River Basin in New York. All samples were collected from June through December 2014 to characterize groundwater quality in these basins. The samples were collected and processed using standard procedures of the U.S. Geological Survey and were analyzed for 148 physiochemical properties and constituents, including dissolved gases, major ions, nutrients, trace elements, pesticides, volatile organic compounds, radionuclides, and indicator bacteria.The Lake Champlain Basin study area covers the 3,050 square miles of the basin in northeastern New York; the remaining part of the basin is in Vermont and Canada. Of the 13 wells sampled in the Lake Champlain Basin, 6 are completed in sand and gravel, and 7 are completed in bedrock. Groundwater in the Lake Champlain Basin was generally of good quality, although properties and concentrations of some constituents— fluoride, iron, manganese, dissolved solids, sodium, radon-222, total coliform bacteria, fecal coliform bacteria, and Escherichia coli bacteria—sometimes equaled or exceeded primary, secondary, or proposed drinking-water standards. The constituent most frequently detected in concentrations exceeding drinking-water standards (5 of 13 samples) was radon-222.The Susquehanna River Basin study area covers the entire 4,522 square miles of the basin in south-central New York; the remaining part of the basin is in Pennsylvania. Of the 20 wells sampled in the Susquehanna River Basin, 11 are completed in sand and gravel, and 9 are completed in bedrock. Groundwater in the Susquehanna River Basin was generally of good quality, although properties and concentrations of some constituents—pH, chloride, sodium, dissolved

  1. Model for the evolution of river networks

    Energy Technology Data Exchange (ETDEWEB)

    Leheny, R.L.; Nagel, S.R. (The James Franck Institute and the Department of Physics, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637 (United States))

    1993-08-30

    We have developed a model, which includes the effects of erosion both from precipitation and from avalanching of soil on steep slopes, to simulate the formation and evolution of river networks. The avalanches provide a mechanism for competition in growth between neighboring river basins. The changing morphology follows many of the characteristics of evolution set forth by Glock. We find that during evolution the model maintains the statistical characteristics measured in natural river systems.

  2. Technical evaluation of a total maximum daily load model for Upper Klamath and Agency Lakes, Oregon

    Science.gov (United States)

    Wood, Tamara M.; Wherry, Susan A.; Carter, James L.; Kuwabara, James S.; Simon, Nancy S.; Rounds, Stewart A.

    2013-01-01

    TMDL model also contributed to this review. Cores were sequentially extracted to determine the distribution of phosphorus associated with several matrices in the sediment (freely exchangeable, metal-oxides, acid-soluble minerals, and residual). The concentrations of phosphorus in these fractions varied around the lake in patterns that reflect transport processes in the lake and the ultimate deposition of organic and inorganic forms of phosphorus from the water column. Both organic and inorganic phosphorus had higher concentrations in the northern part of the lake, in and just west of Goose Bay. At the time that these cores were collected, prior to restoration of the Williamson River Delta, this area was close to the shoreline of the lake and east of the Williamson River mouth. This contrasts with erosional inputs, which, in addition to being high to the east of the pre-restoration Williamson River mouth, were higher in the middle of the lake than at the northern end. Organic forms of phosphorus had particularly high concentrations in the northern bays. When these cores were used to calculate a new estimate of the whole-lake-averaged concentration of total phosphorus in the top 10 centimeters of the lake sediments, the estimate was about one-third of the best estimate available when the TMDL model was developed.

  3. Glacial Lake Outburst Flood Risk in the Poiqu/Bhote Koshi/Sun Koshi River Basin in the Central Himalayas

    Directory of Open Access Journals (Sweden)

    Narendra Raj Khanal

    2015-11-01

    Full Text Available The Himalayas have experienced several glacial lake outburst floods (GLOFs, and the risk of GLOFs is now increasing in the context of global warming. Poiqu watershed in the Tibet Autonomous Region, China, also known as the Bhote Koshi and Sun Koshi downstream in Nepal, has been identified as highly prone to GLOFs. This study explored the distribution of and changes in glacial lakes, past GLOFs and the resulting losses, risk from potential future GLOFs, and risk reduction initiatives within the watershed. A relationship was established between lake area and volume of lake water based on data from 33 lakes surveyed within the Hindu Kush Himalayan region, and the maximum possible discharge was estimated using this and other previously developed empirical equations. We recommend different strategies to reduce GLOF risk and highlight the need for a glacial lake monitoring and early-warning system. We also recommend strong regional cooperation, especially on issues related to transboundary rivers.

  4. Development and evaluation of a physically-based lake level model for water resource management: A case study for Lake Buchanan, Texas

    Directory of Open Access Journals (Sweden)

    Peirong Lin

    2015-09-01

    New hydrological insights: Different from traditional grid-based solutions, the framework is directly coupled on the vector-based NHDPlus dataset, which defines accurate hydrologic features such as rivers, dams, lakes and reservoirs. The resulting hybrid framework therefore allows for more flexibility in resolving “scaling-issues” between large-scale climate models and fine-scale applications. The presented hindcast results also provide insight into the influences of baseline LSM resolutions, initialization months, and lead times, which would ultimately help improve lake-level forecast skills.

  5. Coleoptera associated with macrophytes of the genus Salvinia in four oxbow lakes in two river basins in southeast Brazil.

    Science.gov (United States)

    Paula-Bueno, M C; Fonseca-Gessner, A A

    2015-11-01

    Macrophytes in oxbow lakes represent an important substrate for the Coleoptera. Two oxbow lakes the Rio Paranapanema were studied and the other two Rio Mogi-Guaçu, in the State de São Paulo, Brasil. In this study, there is greater similarity between the communities of Coleoptera of lakes greater connectivity with the main river channel or the difference in the species of Salvinia collected in the lakes studied interferes Coleoptera fauna that uses as substrate. A total of 9,222 specimens of Coleoptera were collected and identified in 10 families and 40 genera. The analysis MDS for abundance of Coleoptera showed the grouping of the oxbow lakes the Paranapanema River and a distancing the oxbow lakes the Mogi-Guaçu. The PERMANOVA test did not reveal any difference in the fauna between the wet and dry periods. It was concluded that the connectivity between river and lake is not decisive for the richness and abundance of aquatic fauna of Coleoptera. Therefore, the richness and abundance of aquatic Coleoptera associated vary with the species of Salvinia used as substrate.

  6. Risk and toxicity assessments of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake, China.

    Science.gov (United States)

    Fu, Jie; Hu, Xin; Tao, Xiancong; Yu, Hongxia; Zhang, Xiaowei

    2013-11-01

    Heavy metal pollution is one of the most serous environmental issues globally. To evaluate the metal pollution in Jiangsu Province of China, the total concentrations of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake were analyzed. Ecological risk of sediments and human health risk of fish consumption were assessed respectively. Furthermore, toxicity of samples on expression of the stress responsive genes was evaluated using microbial live cell-array method. The results showed that the heavy metals concentrations in sediments from the Yangtze River were much higher than those in sediments from the Taihu Lake. However, the fishes from the Taihu Lake had higher concentrations of heavy metals than fishes from the Yangtze River. Ecological risk evaluation showed that the heavy metal contaminants in sediments from the Yangtze River posed higher risk of adverse ecological effects, while sediments from the study areas of Taihu Lake were relatively safe. Health risk assessment suggested that the heavy metals in fishes of both Yangtze River and Taihu Lake might have risk of adverse health effects to human. The toxicity assessment indicated that the heavy metals in these sediments and fishes showed transcriptional effects on the selected 21 stress responsive genes, which were involved in the pathways of DNA damage response, chemical stress, and perturbations of electron transport. Together, this field investigation combined with chemical analysis, risk assessment and toxicity bioassay would provide useful information on the heavy metal pollution in Jiangsu Province.

  7. Underflows in Lake Constance - Numerical Modeling, Instrumental Observations and Sediment Data

    Science.gov (United States)

    Eder, Magdalena; Wessels, Martin; Dare, Julian

    2014-05-01

    A torrential rain event in the western Alps in August 2005 caused high flood flows in the rivers Alpine Rhine and Bregenzer Ache which are the main tributaries into Lake Constance. The discharge of the Alpine Rhine reached 2200 m³/s, which is little below a centennial flood event. Discharge of the Bregenzer Ache was estimated to 1350 m³/s which statistically occurs every 100 yr but with a 1000 yr frequency in selected smaller tributaries. The high concentration of suspended solids in the fluvial water increased its density and created an underflow with considerable influence on the lake's hydrodynamics and water quality. Consequences within the lake were directly registered by a mooring (equipped with thermistor chain, sediment trap, current meter, oxygen sensor). Spatial data of the path and form of suspended matter cloud within the lake were gathered using echo sounder and probe measurements (turbidity, temperature, salinity). An underflow with a temperature of 14°C flew with 1.4 km/h some 20 km into the lake. Several days after the event, the fluvial sediments were detected as increased turbidity at the drinking water outtakes around the lake. Sediment cores recovered from the lake bottom show the distribution pattern of the sediments while sidescan data give a picture from proximal sediment structures originating from this event. Further, we modelled this underflow using the three dimensional hydrodynamic and water quality model ELCOM-CAEDYM. The suspended solids module of the model accounts for the impact of the sediment load on water density. Settling is considered using Stokes Law, and resuspension can also be included. The simulation of the August 2005 flood event and comparison with measured data impressively showed the ability to reproduce the most important effects of the flood flow on the lake. Comparative simulations with and without consideration of the coriolis effect indicate an influence of the coriolis force on the flow path of the density

  8. Impact of riverine suspended particulate matter on the branched glycerol dialkyl glycerol tetraether composition of lakes: The outflow of the Selenga River in Lake Baikal (Russia)

    NARCIS (Netherlands)

    De Jonge, C.; Stadnitskaia, A.; Fedotov, A.; Sinninghe Damsté, J.S.

    2015-01-01

    Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids found in several environments, including soils, rivers and lakes, whose distribution varies with temperature and pH, although this dependence is apparently not the same for the different environments. Mixing of

  9. Impact of riverine suspended particulate matter on the branched glycerol dialkyl glycerol tetraether composition of lakes : The outflow of the Selenga River in Lake Baikal (Russia)

    NARCIS (Netherlands)

    De Jonge, C.|info:eu-repo/dai/nl/371751187; Stadnitskaia, A.N.; Fedotov, Andrey; Sinninghe Damste, J.S.|info:eu-repo/dai/nl/07401370X

    Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids found in several environments, including soils, rivers and lakes, whose distribution varies with temperature and pH, although this dependence is apparently not the same for the different environments. Mixing of

  10. Modeling lakes and reservoirs in the climate system

    NARCIS (Netherlands)

    MacKay, M.D.; Neale, P.J.; Arp, C.D.; De Senerpont Domis, L.N.; Fang, X.; Gal, G.; Jöhnk, K.D.; Kirillin, G.; Lenters, J.D.; Litchman, E.; MacIntyre, S.; Marsh, P.; Melack, J.; Mooij, W.M.; Peeters, F.; Quesada, A.; Schladow, S.G.; Schmid, M.; Spence, C.; Stokes, S.L.

    2009-01-01

    Modeling studies examining the effect of lakes on regional and global climate, as well as studies on the influence of climate variability and change on aquatic ecosystems, are surveyed. Fully coupled atmosphere–land surface–lake climate models that could be used for both of these types of study simu

  11. Benthos and plankton community data for selected rivers and harbors along Wisconsin's Lake Michigan shoreline, 2012

    Science.gov (United States)

    Scudder Eikenberry, Barbara C.; Bell, Amanda H.; Burns, Daniel J.; Templar, Hayley A.

    2014-01-01

    Four river systems on the Wisconsin shoreline of Lake Michigan are designated Areas of Concern (AOCs) because of severe environmental degradation: the Lower Menominee River, Lower Green Bay and Fox River, Sheboygan River, and Milwaukee Estuary. Each AOC has one or more Beneficial Use Impairments (BUIs) that form the basis of the AOC designation and that must be remediated or otherwise addressed before the AOC designation can be removed. All four of these AOCs have BUIs for benthos (bottom-dwelling or benthic invertebrates), and all but the Menominee River have a BUI for plankton (free-floating algae and invertebrates, or phytoplankton and zooplankton, respectively). The U.S. Geological Survey collected samples in 2012 at these four AOCs and at six non-AOCs to support the evaluation of the status of aquatic communities in the benthos and plankton at the AOCs. Samples were collected during three periods representing spring, summer, and fall. Benthos samples were collected using a dredge grab sampler and artificial substrates; plankton samples were collected using a tow net for zooplankton and a vertical water sampler for phytoplankton. Benthos and plankton were identified to the lowest possible taxonomic category and counted; samples for documenting water temperature, pH, and specific conductance, as well as sediment particle size and organic carbon were also collected during biological sampling.

  12. Zooplankton composition in five oxbow lakes from the Upper Juruá River, Acre State, Brazil

    Directory of Open Access Journals (Sweden)

    Maria José Alencar dos Santos

    2013-12-01

    Full Text Available This work was conducted in five oxbow lakes located between Cruzeiro do Sul and Rodrigues Alves counties (Acre State, Brazil, to provide additional information about the composition of zooplankton assemblages in the Upper Juruá River. Samples were collected from May 2009 to May 2010, and fixed with 4% formalina. The numeric density (ind.m -3 was obtained from subsequent sub-samples (1 mL. The study recorded 19 zooplankton families. Rotifers showed higher species richness (81 species, followed by cladocerans (3 species and various forms of copepods and other organisms. Higher zooplankton means of numeric density was found in Novo Lake, with rotifers (1879 ind.m -3, cladocerans (207 ind.m -3, copepods (870 ind.m -3 . Diversity and numeric density were similar to other Neotropical aquatic ecosystems.

  13. Vertical distribution of radionuclides in three lakes along the river Aare in Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Putyrskaya, V.; Klemt, E. [Hochschule Ravensburg-Weingarten (Germany); Roellin, S.; Sahli, H.; Holzer, R. [Spiez Laboratory (Switzerland)

    2014-07-01

    During the years 2009-2013 sediment cores with lengths of about 1 m were taken from Lake Brienz, Lake Thun, and Lake Biel. River Aare coming from glaciers in the Grimsel area is flowing essentially to the north through lakes Brienz and Thun, and then passing the capital Bern. North of Bern the nuclear power plant Muehleberg is located on the banks of River Aare which then passes Lake Biel. Sediment cores were sliced into 1 cm layers, freeze-dried and homogenized. Gamma-spectroscopy was performed with HPGe-detectors (BEGe-5030 with carbon windows) after sealing the samples into radon-tight aluminium composite foil. Self-absorption in the samples and summation corrections in the spectrum were taken into account. Later on, complete lithium borate fusions of sediment samples were performed and the molten samples were poured into concentrated nitric acid. After the silicates were precipitated, plutonium was separated with Teva-columns. ICP-MS measurements were performed to determine the content of different Pu-isotopes. In sediments of all three lakes maxima in the {sup 137}Cs distributions could be assigned to the maximum of the atmospheric nuclear weapons testing fallout in 1963 which was confirmed by the Pu distributions and by the presence of {sup 241}Am. Another peak had to be assigned to the fallout of the Chernobyl nuclear accident in 1986. Confirmation that the top layer had not been lost during sampling is given by the presence of {sup 7}Be in those layers. Dating of sediment layers is also done by {sup 210}Pb methods. Here the unsupported {sup 210}Pb is received by subtracting the supported {sup 210}Pb (determined via {sup 214}Pb or {sup 214}Bi which are in secular equilibrium with {sup 226}Ra) from the total {sup 210}Pb. Pb-dating is in good agreement with Cs-dating and provides a time-dependent sedimentation rate. Single events which led to high sedimentation rates can also be identified by variations of the {sup 40}K concentration, bulk density and by

  14. Studies on the changes of West Lake's zoobenthic communites after Qiantang River water was pumped into it

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    During Jan.1995 to Dec.1996, monthly investigations on the zoobenthic communities of West Lake, samples were collected from six sampling stations. A total of 26 species of macrozoobenthos were identified. The seasonal changes in density and biomass of zoobenthos in this lake were analyzed. The annual mean densities were 980~2751 ind/m2 and mean biomass was 19.69-122.80 g/m2. The densities in winter and early spring were higher than those in summer and autumn. Comparative study of theprevious data (1982 to 1983) collected by the authors, showed that the succession of zoobenthic communities, dominated by Procludius choreus in density and Bellamya purificata in biomass, had been occurred in Xiaonan sub-lake after Qiantang River water was drawn into it; and that the species and biomass of zoobenthos were then increased and the density was decreased. In other sub-lakes, the dominant species were Limnodrilus hoffmeisteri and Tokunagayusurika akamusi in density and Branchiura sowerbyi and Tokunagayusurika akamusi in biomass. The water quality was bad in these sub-lakes because these dominant species are indicators of eutrophication. According to the Margalef index and Goodnight index, West Lake is still an eutrophic lake. Only the water quality of Xiaonan sub-lake was improved after water drawn from the Qiantang River was introduced into it.

  15. Nutrient inputs to the Laurentian Great Lakes by source and watershed estimated using SPARROW watershed models

    Science.gov (United States)

    Robertson, Dale M.; Saad, David A.

    2011-01-01

    Nutrient input to the Laurentian Great Lakes continues to cause problems with eutrophication. To reduce the extent and severity of these problems, target nutrient loads were established and Total Maximum Daily Loads are being developed for many tributaries. Without detailed loading information it is difficult to determine if the targets are being met and how to prioritize rehabilitation efforts. To help address these issues, SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed for estimating loads and sources of phosphorus (P) and nitrogen (N) from the United States (U.S.) portion of the Great Lakes, Upper Mississippi, Ohio, and Red River Basins. Results indicated that recent U.S. loadings to Lakes Michigan and Ontario are similar to those in the 1980s, whereas loadings to Lakes Superior, Huron, and Erie decreased. Highest loads were from tributaries with the largest watersheds, whereas highest yields were from areas with intense agriculture and large point sources of nutrients. Tributaries were ranked based on their relative loads and yields to each lake. Input from agricultural areas was a significant source of nutrients, contributing ∼33-44% of the P and ∼33-58% of the N, except for areas around Superior with little agriculture. Point sources were also significant, contributing ∼14-44% of the P and 13-34% of the N. Watersheds around Lake Erie contributed nutrients at the highest rate (similar to intensively farmed areas in the Midwest) because they have the largest nutrient inputs and highest delivery ratio.

  16. Biological and chemical characterization of metal bioavailability in sediments from Lake Roosevelt, Columbia River, Washington, USA

    Science.gov (United States)

    Besser, J.M.; Brumbaugh, W.G.; Ivey, C.D.; Ingersoll, C.G.; Moran, P.W.

    2008-01-01

    We studied the bioavailability and toxicity of copper, zinc, arsenic, cadmium, and lead in sediments from Lake Roosevelt (LR), a reservoir on the Columbia River in Washington, USA that receives inputs of metals from an upstream smelter facility. We characterized chronic sediment toxicity, metal bioaccumulation, and metal concentrations in sediment and pore water from eight study sites: one site upstream in the Columbia River, six sites in the reservoir, and a reference site in an uncontaminated tributary. Total recoverable metal concentrations in LR sediments generally decreased from upstream to downstream in the study area, but sediments from two sites in the reservoir had metal concentrations much lower than adjacent reservoir sites and similar to the reference site, apparently due to erosion of uncontaminated bank soils. Concentrations of acid-volatile sulfide in LR sediments were too low to provide strong controls on metal bioavailability, and selective sediment extractions indicated that metals in most LR sediments were primarily associated with iron and manganese oxides. Oligochaetes (Lumbriculus variegatus) accumulated greatest concentrations of copper from the river sediment, and greatest concentrations of arsenic, cadmium, and lead from reservoir sediments. Chronic toxic effects on amphipods (Hyalella azteca; reduced survival) and midge larvae (Chironomus dilutus; reduced growth) in whole-sediment exposures were generally consistent with predictions of metal toxicity based on empirical and equilibrium partitioning-based sediment quality guidelines. Elevated metal concentrations in pore waters of some LR sediments suggested that metals released from iron and manganese oxides under anoxic conditions contributed to metal bioaccumulation and toxicity. Results of both chemical and biological assays indicate that metals in sediments from both riverine and reservoir habitats of Lake Roosevelt are available to benthic invertebrates. These findings will be used as

  17. A modified QWASI model for fate and transport modeling of mercury between the water-ice-sediment in Lake Ulansuhai.

    Science.gov (United States)

    Liu, Yu; Li, Changyou; Anderson, Bruce; Zhang, Sheng; Shi, Xiaohong; Zhao, Shengnan

    2017-06-01

    Mercury contamination from industrial and agricultural drainage into lakes and rivers is a growing concern in Northern China. Lake Ulansuhai, located in Hetao irrigation district in Inner Mongolia, is the only sink for the all industrial and agricultural drainage and sole outlet for this district to the Yellow River, which is one of the main source of drinking water for the numerous cities and towns downstream. Because Ulansuahi is ice-covered during winter, the QWASI model was modified by adding an ice equation to get a more accurate understanding of the fate and transport of mercury within the lake. Both laboratory and field tests were carried out during the ice growth period. The aquivalence and mass balance approaches were used to develop the modified QWASI + ice model. The margins of error between the modelled and the measured average concentrations of Hg in ice, water, and sediment were 30%, 26.2%, and 19.8% respectively. These results suggest that the new QWASI + ice model could be used to more accurately represent the fate and transport of mercury in the seasonally ice-covered lakes, during the ice growth period.

  18. Evaluation of stream water quality data generated from MODIS images in modeling total suspended solid emission to a freshwater lake.

    Science.gov (United States)

    Ayana, Essayas K; Worqlul, Abeyou W; Steenhuis, Tammo S

    2015-08-01

    Modeling of suspended sediment emission into freshwater lakes is challenging due to data gaps in developing countries. Existing models simulate sediment concentration at a gauging station upstream and none of these studies had modeled total suspended solids (TSS) emissions by inflowing rivers to freshwater lakes as there are no TSS measurements at the river mouth in the upper Blue Nile basin. In this study a 10year TSS time series data generated from remotely sensed MODIS/Terra images using established empirical relationship is applied to calibrate and validate a hydrology model for Lake Tana in Upper Blue Nile Basin. The result showed that at a monthly time scale TSS at the river mouth can be replicated with Nash-Sutcliffe efficiency (NS) of 0.34 for calibration and 0.21 for validation periods. Percent bias (PBIAS) and ratio of the root-mean-square error to the standard deviation of measured data (RSR) are all within range. Given the inaccessibility and costliness to measure TSS at river mouths to a lake the results found here are considered useful for suspended sediment budget studies in water bodies of the basin. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. SHRIMP dating of the Bangong Lake SSZ-type ophiolite:Constraints on the closure time of ocean in the Bangong Lake-Nujiang River, northwestern Tibet

    Institute of Scientific and Technical Information of China (English)

    SHI RenDeng

    2007-01-01

    The Bangong Lake ophiolite is located in the westernmost part of the Bangong Lake-Nujiang River and massive lavas and mafic dykes with SSZ-type ophiolitic geochemical affinity formed at the end of a Wilson circle. The SHRIMP U-Pb ages of the co-magmatic zircon domains from one gabbroic dyke (Sample 01Y-155) range from 162.5±8.6 Ma to 177.1±1.4 Ma with an average of 167.0+1.4 Ma (n = 12,MSWD = 1.2), suggesting that the subduction of the Bangong Lake Neo-Tethyan Ocean started before the Middle Jurassic. It is inferred that the tectonic transform from spreading to subduction of the Neo-Tethyan Ocean began before the Middle Jurassic in the Bangong Lake area.

  20. Impact of Lake Gopło on low-flow regime of the upper Noteć river

    Directory of Open Access Journals (Sweden)

    Tomaszewski Edmund

    2016-12-01

    Full Text Available The main aim of this study is to make an assessment of the impact of Lake Gopło on a river low-flow regime. Two water gauges were selected, located in an upstream and downstream position to the lake on the River Noteć. On the basis of the daily discharge series from the period 1965–1990, a group of low-flow regime estimators was computed. Analyses involved various aspects of minimum flows and drought streamflow deficits. Comparison of the data between both gauging stations showed the extent of the influence of water management on Lake Gopło on low-flow regime transformation in the River Noteć.

  1. International Cooperative Programme for Assessment and Monitoring of Acidification of Rivers and Lakes. Programme Manual

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, J.; Forsius, M.; Jeffries, D. [and others

    1996-12-31

    The International Cooperative Programme for Assessment of Acidification of Rivers and lakes (ICP Waters) was established in 1985 by the UN/ECE Executive Body for the Convention of Long-Range Transboundary Air Pollution. Achieving the programme objectives requires that both the temporally intensive and regionally extensive data are collected on a continuing basis. To guide the development and harmonization of the various national contributions, a manual was worked out. The present report is an expanded and consolidated revision of that manual. 33 refs., 3 tabs.

  2. Acid precipitation and other possible sources for acidification of rivers and lakes

    Energy Technology Data Exchange (ETDEWEB)

    Seip, H.M.; Tollan, A.

    1978-01-01

    The trends in the recent acidification of rivers and lakes in South Norway are reviewed, and the evidence for a causal relationship between acid precipitation and acidification of surface water is critically examined. Results from regional surveys, studies in small catchment areas and from percolation experiments are presented. Several sources may contribute to the acidification. However, changes in the composition of the precipitation during the recent decades, mainly because of increased combustion of fossil fuels, seem to be a dominant cause at least in some of the most affected areas.

  3. GCMS Determination of Organochlorine Pesticides (OCPs in Fish from River Cauvery and Veeranam Lake

    Directory of Open Access Journals (Sweden)

    R. Bhuvaneshwari

    2012-01-01

    Full Text Available Organochlorine Pesticides (OCPs were analyzed using Gas Chromatography-Mass Spectrometer (Selective Ion Monitoring mode in the muscle tissues of five fish species such as O. mossambicus, L. parsia, E. suretensis, C. striata and S. wynaadensis from seven locations of River Cauvery and one location in Veeranam Lake. OCPs viz., DDTs, HCHs, CHLs, cyclodienes, heptachlor, HCB and mirex were detected with varying concentrations among species and locations. Mirex which was not reported in the fish tissues elsewhere reported in this study. The study on the risk associated with the consumption of fish species that had higher concentrations of aldrin, dieldrin and mirex showed significant carcinogenic risk to the human beings.

  4. 33 CFR 165.T09-0166 - Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone, Brandon Road Lock and Dam to Lake Michigan including Des Plaines River, Chicago Sanitary and Ship Canal, Chicago River... Areas Ninth Coast Guard District § 165.T09-0166 Safety Zone, Brandon Road Lock and Dam to Lake...

  5. Using radar altimetry to update a large-scale hydrological model of the Brahmaputra river basin

    DEFF Research Database (Denmark)

    Finsen, F.; Milzow, Christian; Smith, R.

    2014-01-01

    Measurements of river and lake water levels from space-borne radar altimeters (past missions include ERS, Envisat, Jason, Topex) are useful for calibration and validation of large-scale hydrological models in poorly gauged river basins. Altimetry data availability over the downstream reaches...... of the Brahmaputra is excellent (17 high-quality virtual stations from ERS-2, 6 from Topex and 10 from Envisat are available for the Brahmaputra). In this study, altimetry data are used to update a large-scale Budyko-type hydrological model of the Brahmaputra river basin in real time. Altimetry measurements...... are converted to discharge using rating curves of simulated discharge versus observed altimetry. This approach makes it possible to use altimetry data from river cross sections where both in-situ rating curves and accurate river cross section geometry are not available. Model updating based on radar altimetry...

  6. Modelling planform changes of braided rivers

    NARCIS (Netherlands)

    Jagers, Hendrik Reinhard Albert

    2003-01-01

    This study has focused on modelling techniques to predict planform changes of braided rivers and their relation with state-of-the-art knowledge on the physical processes and the availability of model input data

  7. Spatio-temporal development of high-mountain lakes in the headwaters of the Amu Darya River (Central Asia)

    Science.gov (United States)

    Mergili, Martin; Müller, Johannes P.; Schneider, Jean F.

    2013-08-01

    The sources of the Amu Darya, one of the major Central Asian rivers draining to the Aral Sea, are located in the glacierized high-mountain areas of Tajikistan, Kyrgyzstan and Afghanistan. There, climate change and the resulting retreat of glaciers have led to the formation of numerous new glacial lakes. Other lakes in the area are embedded in older glacial landscapes (erosion lakes) or retained by block or debris dams (e.g., Lake Sarez). A multi-temporal lake inventory is prepared and analysed, based on remotely sensed data. Corona images from 1968 are used as well as more up-to-date ASTER and Landsat 7 scenes. 1642 lakes are mapped in total, 652 out of them are glacial lakes. 73% of all lakes are located above 4000 m a.s.l. Glacial lakes, abundant in those areas where glacier tongues retreat over flat or moderately steep terrain, have experienced a significant growth, even though changes are often superimposed by short-term fluctuations. The analysis results also indicate a shifting of the growth of glacial lakes from the south western Pamir to the central and northern Pamir during the observation period. This trend is most likely associated with more elevated contribution areas in the central and northern Pamir. The lakes of the other types have remained constant in size in general. The lake development reflects changes in the state of the water resources in the study area on the one hand and determines the level of lake outburst hazards on the other hand.

  8. Monitoring Bedfast Ice and Ice Phenology in Lakes of the Lena River Delta Using TerraSAR-X Backscatter and Coherence Time Series

    Directory of Open Access Journals (Sweden)

    Sofia Antonova

    2016-11-01

    Full Text Available Thermokarst lakes and ponds are major elements of permafrost landscapes, occupying up to 40% of the land area in some Arctic regions. Shallow lakes freeze to the bed, thus preventing permafrost thaw underneath them and limiting the length of the period with greenhouse gas production in the unfrozen lake sediments. Radar remote sensing permits to distinguish lakes with bedfast ice due to the difference in backscatter intensities from bedfast and floating ice. This study investigates the potential of a unique time series of three-year repeat-pass TerraSAR-X (TSX imagery with high temporal (11 days and spatial (10 m resolution for monitoring bedfast ice as well as ice phenology of lakes in the zone of continuous permafrost in the Lena River Delta, Siberia. TSX backscatter intensity is shown to be an excellent tool for monitoring floating versus bedfast lake ice as well as ice phenology. TSX-derived timing of ice grounding and the ice growth model CLIMo are used to retrieve the ice thicknesses of the bedfast ice at points where in situ ice thickness measurements were available. Comparison shows good agreement in the year of field measurements. Additionally, for the first time, an 11-day sequential interferometric coherence time series is analyzed as a supplementary approach for the bedfast ice monitoring. The coherence time series detects most of the ice grounding as well as spring snow/ice melt onset. Overall, the results show the great value of TSX time series for monitoring Arctic lake ice and provide a basis for various applications: for instance, derivation of shallow lakes bathymetry, evaluation of winter water resources and locating fish winter habitat as well as estimation of taliks extent in permafrost.

  9. Assessing inflow alterations into Lake Baikal from Selenga river basin with respect to changing climate and land use conditions

    Science.gov (United States)

    Moreido, Vsevolod; Kalugin, Andrey; Motovilov, Yuri; Millionshchikova, Tatiana

    2017-04-01

    The trans-boundary Selenga river basin is the largest tributary of Lake Baikal, which has been experiencing a profound increase of annual near-surface air temperature - 1.6 to 1.8⁰C during the last 70 years, nearly twice as global increase. A significant drought that has been registered in the Selenga basin for the last 20 years has drawn attention of a number of hydrologists worldwide to investigate its drivers. In this study we used the ECOMAG hydrological modeling software to construct a semi-distributed data-driven hydrological model that accounts for weather forcing, hydrological soil properties and land-use conditions to assess runoff generation in the river basin and its current and future response to climate and land-use alteration. Due to lack of daily weather observation data, the model was driven with EWEMBI weather dataset for calibration and validation purposes. To investigate the possible impact on runoff due to climate change in the XXI century we used an ensemble of 7 GCMs from CMIP5 experiment operating according to 4 IPCC greenhouse gas RCPs. To account for possible land-use changes we used HYDE dataset for the years 1990-2100. The modeling results show that the current drought conditions may be prolonged and intensified according to the most severe RCPs. At the same time, land-use conditions appear to have limited influence on the runoff generation for this area is not subject to heavy irrigation-intensive agriculture.

  10. Role of minerogenic particles in light scattering in lakes and a river in central New York

    Science.gov (United States)

    Peng, Feng; Effler, Steven W.; O'Donnell, David; Perkins, Mary Gail; Weidemann, Alan

    2007-09-01

    The role of minerogenic particles in light scattering in several lakes and a river (total of ten sites) in central New York, which represent a robust range of scattering conditions, was evaluated based on an individual particle analysis technique of scanning electron microscopy interfaced with automated x-ray microanalysis and image analysis (SAX), in situ bulk measurements of particle scattering and backscattering coefficients (bp and bbp), and laboratory analyses of common indicators of scattering. SAX provided characterizations of the elemental x-ray composition, number concentration, particle size distribution (PSD), shape, and projected area concentration of minerogenic particles (PAVm) of sizes >0.4 μm. Mie theory was applied to calculate the minerogenic components of bp (bm) and bbp (bb,m) with SAX data. Differences in PAVm, associated primarily with clay minerals and CaCO3, were responsible for most of the measured differences in both bp and bbp across the study sites. Contributions of the specified minerogenic particle classes to bm were found to correspond approximately to their contributions to PAVm. The estimates of bm represented substantial fractions of bp, whereas those of bb,m were the dominant component of bbp. The representativeness of the estimates of bm and bb,m was supported by their consistency with the bulk measurements. Greater uncertainty prevails for the bb,m estimates than those for bm, associated primarily with reported deviations in particle shapes from sphericity. The PSDs were well represented by the "B" component of the two-component model or a three parameter generalized gamma distribution [Deep-Sea Res. Part I 40, 1459 (1993)]. The widely applied Junge (hyperbolic) function performed poorly in representing the PSDs and the size dependency of light scattering in these systems, by overrepresenting the concentrations of submicrometer particles especially. Submicrometer particles were not important contributors to bm or bb,m.

  11. Spatial and temporal variability of river periphyton below a hypereutrophic lake and a series of dams.

    Science.gov (United States)

    Gillett, Nadia D; Pan, Yangdong; Eli Asarian, J; Kann, Jacob

    2016-01-15

    Klamath River is described as an "upside-down" river due to its origins from the hypereutrophic Upper Klamath Lake (UKL) and hydrology that is heavily regulated by upstream dams. Understanding the lake and reservoir effects on benthic communities in the river can inform important aspects of its water quality dynamics. Periphyton samples were collected in May-November from 2004, 2006-2013 at nine long-term monitoring sites along 306 river km below UKL and a series of dams (n=299). Cluster analysis of periphyton assemblages identified three statistically different periphyton groups (denoted Groups 1-3). Group 1 occurred primarily in the upstream reach for June-October and had a higher percentage of sestonic species, including the cyanobacteria Aphanizomenon flos-aquae and Microcystis aeruginosa, consistent with the presence of upstream reservoirs. Group 2 had the highest relative biomass of diatoms and lowest relative biomass of cyanobacteria. Sites in the lower reach of the Klamath River fell into Group 2 in May-June and transitioning into Group 3 for July-October. Group 3 was dominated by nitrogen (N)-fixing species, including three diatoms (Epithemia sorex, Epithemia turgida, and Rhopalodia gibba) with cyanobacterial endosymbionts and the cyanobacterium Calothrix sp. Periphyton assemblages were strongly associated with temporal variations in flow conditions (e.g., decreasing flow from spring to fall) and spatial gradients in nutrient concentrations (e.g., decreasing from upstream to downstream). The inverse longitudinal relationship between periphyton biomass and nutrients may be explained by the ability of benthic N-fixers (Group 3) to overcome N limitation. Overall results showed a strong inverse relationship between the relative biomass of N-fixers and nitrogen concentrations and flow. This long-term dataset provides valuable insight into Klamath River's seasonal and longitudinal patterns of benthic algal communities and associated environmental variables. Our

  12. 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.

  13. An evaluation of the evolution of the latest miocene to earliest pliocene bouse lake system in the lower Colorado river valley, southwestern USA

    Science.gov (United States)

    Spencer, J.E.; Pearthree, P.A.; House, P.K.

    2008-01-01

    The upper Miocene to lower Pliocene Bouse Formation in the lower Colorado River trough of the American Southwest was deposited in three basins - from north to south, the Mohave, Havasu, and Blythe Basins - that were formed by extensional fault ing in the early to middle Miocene. Fossils of marine, brackish, and freshwater organ isms in the Bouse Formation have been interpreted to indicate an estuarine environment associated with early opening of the nearby Gulf of California. Regional uplift since 5 Ma is required to position the estuarine Bouse Formation at present elevations as high as 555 m, where greater uplift is required in the north. We present a compilation of Bouse Formation elevations that is consistent with Bouse deposition in lakes, with an abrupt 225 m northward increase in maximum Bouse elevations at Topock gorge north of Lake Havasu. Within Blythe and Havasu Basins, maximum Bouse elevations are 330 m above sea level in three widely spaced areas and reveal no evidence of regional tilting. To the north in Mohave Basin, numerous Bouse outcrops above 480 m elevation include three widely spaced sites where the Bouse Formation is exposed at 536-555 m. Numerical simulations of initial Colorado River inflow to a sequence of closed basins along the lower Colorado River corridor model a history of lake filling, spilling, evaporation and salt concentration, and outflow-channel incision. The simulations support the plausibility of evaporative concentration of Colorado River water to seawater-level salinities in Blythe Basin and indicate that such salinities could have remained stable for as long as 20-30 k.y. We infer that fossil marine organ isms in the Bouse Formation, restricted to the southern (Blythe) basin, reflect coloniza tion of a salty lake by a small number of species that were transported by birds.

  14. Quantification of surface water and groundwater flows to open- and closed-basin lakes in a headwaters watershed using a descriptive oxygen stable isotope model

    Science.gov (United States)

    Stets, Edward G.; Winter, T. C.; Rosenberry, Donald O.; Striegl, Robert G.

    2010-01-01

    Accurate quantification of hydrologic fluxes in lakes is important to resource management and for placing hydrologic solute flux in an appropriate biogeochemical context. Water stable isotopes can be used to describe water movements, but they are typically only effective in lakes with long water residence times. We developed a descriptive time series model of lake surface water oxygen-18 stable isotope signature (δL) that was equally useful in open- and closed-basin lakes with very different hydrologic residence times. The model was applied to six lakes, including two closed-basin lakes and four lakes arranged in a chain connected by a river, located in a headwaters watershed. Groundwater discharge was calculated by manual optimization, and other hydrologic flows were constrained by measured values including precipitation, evaporation, and streamflow at several stream gages. Modeled and observed δL were highly correlated in all lakes (r = 0.84–0.98), suggesting that the model adequately described δL in these lakes. Average modeled stream discharge at two points along the river, 16,000 and 11,800 m3 d−1, compares favorably with synoptic measurement of stream discharge at these sites, 17,600 and 13,700 m3 d−1, respectively. Water yields in this watershed were much higher, 0.23–0.45 m, than water yields calculated from gaged streamflow in regional rivers, approximately 0.10 m, suggesting that regional groundwater discharge supports water flux through these headwaters lakes. Sensitivity and robustness analyses also emphasized the importance of considering hydrologic residence time when designing a sampling protocol for stable isotope use in lake hydrology studies.

  15. Heavy Metal Pollution, Fractionation, and Potential Ecological Risks in Sediments from Lake Chaohu (Eastern China) and the Surrounding Rivers.

    Science.gov (United States)

    Zhang, Lei; Liao, Qianjiahua; Shao, Shiguang; Zhang, Nan; Shen, Qiushi; Liu, Cheng

    2015-11-06

    Heavy metal (Cr, Ni, Cu, Zn, Cd, and Pb) pollution, fractionation, and ecological risks in the sediments of Lake Chaohu (Eastern China), its eleven inflowing rivers and its only outflowing river were studied. An improved BCR (proposed by the European Community Bureau of Reference) sequential extraction procedure was applied to fractionate heavy metals within sediments, a geoaccumulation index was used to assess the extent of heavy metal pollution, and a risk assessment code was applied to evaluate potential ecological risks. Heavy metals in the Shuangqiao and Nanfei Rivers were generally higher than the other studied sites. Of the three Lake Chaohu sites, the highest concentrations were identified in western Chaohu. Heavy metal pollution and ecological risks in the lake's only outflowing river were similar to those in the eastern region of the lake, to which the river is connected. Heavy metal concentrations occurred in the following order: Cd > Zn > Cu > Pb ≈ Ni ≈ Cr. Cr, Ni, and Cu made up the largest proportion of the residual fraction, while Cd was the most prominent metal in the exchangeable and carbonate-included fraction. Cd posed the greatest potential ecological risk; the heavy metals generally posed risks in the following order: Cd > Zn > Cu > Ni > Pb > Cr.

  16. Audubon National Wildlife Refuge, Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Wintering River Easement Refuge, Cottonwood Lake Easement Refuge, Sheyenne Lake Easement Refuge, Lake Otis Easement Refuge : Narrative report : 1970

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Audubon National Wildlife Refuge (including Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Cottonwood Lake...

  17. Short-term effects of drawing water for connectivity of rivers and lakes on zooplankton community structure

    Institute of Scientific and Technical Information of China (English)

    WU Zhenbin; LIU Aifen; ZHANG Shiyang; CHENG Shuiping; WU Xiaohui

    2008-01-01

    During 28-29,September 2005,water was drawn from Hanjiang River and Houguan Lake to the Yangzi River via Sanjiao Lake and Nantaizi Lake in Wuhan in order to provide favorable conditions for ecosystem restoration.To evaluate the feasibility and validity of drawing water as a means of ecosystem restoration,zooplankton populations were studied 3 times (before,immediately after finishing and a month after drawing water)at seven locations from 27 Sept.2005 to 2 Nov.2005.Water quality in the lakes was mostly improved and zooplankton species richness decreased as soon as drawing water had finished but increased a month after drawing water.Zooplankton density and biomass was reduced in the lakes by drawing water but was increased at the entrance to Sanjiao Lake because of landform geometry change.Before drawing water,most species in Sanjiao lake e.g.,Brachionus sp.and Keratella sp.were tolerant of contamination.After drawing water oligotrophic-prone species such as Lecane ludwigii and Gastropus stylifer emerged.We conclude that drawing water could be important for improving water quality and favour ecosystem restoration.Dilution of nutrient concentrations may be an important role in the effect.

  18. Predicting future glacial lakes in Austria using different modelling approaches

    Science.gov (United States)

    Otto, Jan-Christoph; Helfricht, Kay; Prasicek, Günther; Buckel, Johannes; Keuschnig, Markus

    2017-04-01

    Glacier retreat is one of the most apparent consequences of temperature rise in the 20th and 21th centuries in the European Alps. In Austria, more than 240 new lakes have formed in glacier forefields since the Little Ice Age. A similar signal is reported from many mountain areas worldwide. Glacial lakes can constitute important environmental and socio-economic impacts on high mountain systems including water resource management, sediment delivery, natural hazards, energy production and tourism. Their development significantly modifies the landscape configuration and visual appearance of high mountain areas. Knowledge on the location, number and extent of these future lakes can be used to assess potential impacts on high mountain geo-ecosystems and upland-lowland interactions. Information on new lakes is critical to appraise emerging threads and potentials for society. The recent development of regional ice thickness models and their combination with high resolution glacier surface data allows predicting the topography below current glaciers by subtracting ice thickness from glacier surface. Analyzing these modelled glacier bed surfaces reveals overdeepenings that represent potential locations for future lakes. In order to predict the location of future glacial lakes below recent glaciers in the Austrian Alps we apply different ice thickness models using high resolution terrain data and glacier outlines. The results are compared and validated with ice thickness data from geophysical surveys. Additionally, we run the models on three different glacier extents provided by the Austrian Glacier Inventories from 1969, 1998 and 2006. Results of this historical glacier extent modelling are compared to existing glacier lakes and discussed focusing on geomorphological impacts on lake evolution. We discuss model performance and observed differences in the results in order to assess the approach for a realistic prediction of future lake locations. The presentation delivers

  19. River Network Modeling Beyond Discharge at Gauges

    Science.gov (United States)

    David, C. H.; Famiglietti, J. S.; Salas, F. R.; Whiteaker, T. L.; Maidment, D. R.; Tolle, K.

    2014-12-01

    Over the past two decades, the estimation of water flow in river networks within hydro-meteorological models has mostly focused on simulations of natural processes and on their verification at available river gauges. Despite valuable existing skills in hydrologic modeling the accounting for anthropogenic actions in current models remains limited. The emerging availability of datasets containing measured dam outflows and reported irrigation withdrawals motivates their inclusion into simulations of flow in river networks. However, the development of advanced river network models accounting for such datasets of anthropogenic influences requires a detailed data model and a thorough handling of the various data types, sources and time scales. This contribution details the development of a consistent data model suitable for accounting some observations of anthropogenic modifications of the surface water cycle and presents the impact of such inclusion on simulations using the Routing Application for Parallel computatIon of Discharge (RAPID).

  20. Characteristics of Lake Chad Level Variability and Links to ENSO, Precipitation, and River Discharge

    Directory of Open Access Journals (Sweden)

    Churchill Okonkwo

    2014-01-01

    Full Text Available This study used trend, correlation, and wavelet analysis to characterize Lake Chad (LC level fluctuations, river discharge, El Niño Southern Oscillation (ENSO, and precipitation regimes and their interrelationships. Linear correlation results indicate a negative association between ENSO and LC level, river discharge and precipitation. Trend analysis shows increasing precipitation in the Lake Chad Basin (LCB but decreasing LC level. The mode of interannual variability in LC level, rainfall, and ENSO analyzed using wavelet analysis is dominated by 3-4-year periods. Results show that variability in ENSO could explain only 31% and 13% of variations in LC level at Kindjeria and precipitation in the northern LCB, respectively. The wavelet transform coherency (WTC between LC level of the southern pool at Kalom and ENSO is statistically significant at the 95% confidence level and phase-locked, implying a cause-and-effect association. These strong coherencies coincide with the La Niña years with the exception of 1997-1998 El Niño events. The WTC shows strong covariance between increasing precipitation and LC level in the northern pool at a 2- to 4-year band and 3- to 4-year band localized from 1996 to 2010. Implications for water resource planning and management are discussed.

  1. Surface river plume in a large lake under wind forcing: Observations and laboratory experiments

    Science.gov (United States)

    Demchenko, Natalia; He, Cheng; Rao, Yerubandi R.; Valipour, Reza

    2017-10-01

    Observations of a small riverine plume (Grand River, ON) in the nearshore zones of Lake Erie were analyzed to describe its spatial variability and its thickness under different wind forcing conditions during late spring of 2012. Observational results reveal a well-marked frontal region in the vicinity of the river mouth, causing the plume to discharge into the lake in the surface layers (positive buoyant). Wind driven alongshore currents at the mid-depth had speeds of 2-9 cm/s, in comparison to those in the cross-shore 3-6 cm/s, which transported the plume along the shore during the measurement period. Series of laboratory experiments were conducted to obtain the propagation speed (U) of the buoyant plume in terms of buoyancy anomaly (Ba), Richardson number (Ri), dimensionless time (t‧), and aspect ratio (A). Based on our experiments, we developed two non-dimensional relationships describing the speed of propagation (U) as U/Ba1/2 = 8 Ri-1/2t‧1/3A and the plume thickness (h) as h/H = 0.8 Ri-1/4t‧1/2A in the water depth (H), which are in agreement with field observations.

  2. Dioxins, PCBs and heavy metals in Chinese mitten crabs from Dutch rivers and lakes.

    Science.gov (United States)

    Hoogenboom, Ron L A P; Kotterman, Michiel J J; Hoek-van Nieuwenhuizen, Marion; van der Lee, Martijn K; Mennes, Wim C; Jeurissen, Suzanne M F; van Leeuwen, Stefan P J

    2015-03-01

    Chinese mitten crab is an invasive species in many European rivers and lakes. Data from the UK indicated high levels of dioxins and PCBs, in particular in the brown meat in the body. This was confirmed by studies in the Netherlands, showing average levels of dioxins and PCBs in the meat in the body of 43 pg TEQ g(-1) ww in crabs caught in the large rivers. Levels in crab of lakes in the Northern part of the Netherlands were on average 3.7-fold lower. Consumption of crabs from polluted areas results in a relatively high dose of dioxins and dl-PCBs and could significantly increase the intake above the TWI. However, in general consumption of these crabs is low, even in the Asian sub-population in the Netherlands. Cadmium and lead levels were higher in crabs from contaminated areas, but for mercury and arsenic there was no clear difference. Consumption of crabs would not result in significant risks for cadmium and mercury. For lead the daily intake could be raised above the BMDL01 for neurodevelopmental toxicity, but this would only occur on a limited number of days. For arsenic the exposure would exceed the lower end of the BMDL01 values for certain cancers, but again, the infrequent consumption by most consumers reduces this risk. Furthermore, speciation showed that most arsenic in crabs was probably not a toxic inorganic form, but likely to be in an organic form.

  3. Characteristics of Lake Chad level variability and links to ENSO, precipitation, and river discharge.

    Science.gov (United States)

    Okonkwo, Churchill; Demoz, Belay; Gebremariam, Sium

    2014-01-01

    This study used trend, correlation, and wavelet analysis to characterize Lake Chad (LC) level fluctuations, river discharge, El Niño Southern Oscillation (ENSO), and precipitation regimes and their interrelationships. Linear correlation results indicate a negative association between ENSO and LC level, river discharge and precipitation. Trend analysis shows increasing precipitation in the Lake Chad Basin (LCB) but decreasing LC level. The mode of interannual variability in LC level, rainfall, and ENSO analyzed using wavelet analysis is dominated by 3-4-year periods. Results show that variability in ENSO could explain only 31% and 13% of variations in LC level at Kindjeria and precipitation in the northern LCB, respectively. The wavelet transform coherency (WTC) between LC level of the southern pool at Kalom and ENSO is statistically significant at the 95% confidence level and phase-locked, implying a cause-and-effect association. These strong coherencies coincide with the La Niña years with the exception of 1997-1998 El Niño events. The WTC shows strong covariance between increasing precipitation and LC level in the northern pool at a 2- to 4-year band and 3- to 4-year band localized from 1996 to 2010. Implications for water resource planning and management are discussed.

  4. Coupling of carbon and silicon geochemical cycles in rivers and lakes.

    Science.gov (United States)

    Wang, Baoli; Liu, Cong-Qiang; Maberly, Stephen C; Wang, Fushun; Hartmann, Jens

    2016-10-24

    Carbon (C) and silicon (Si) biogeochemical cycles are important factors in the regulation of atmospheric CO2 concentrations and hence climate change. Theoretically, these elements are linked by chemical weathering and organism stoichiometry, but this coupling has not been investigated in freshwaters. Here we compiled data from global rivers and lakes in the United States of America and the United Kingdom, in order to characterize the stoichiometry between the biogeochemical cycles of C and Si. In rivers this coupling is confirmed by a significant relationship between HCO3(-)/Na(+) and DSi/Na(+), and DSi:HCO3(-) ratio can reflect the mineral source of chemical weathering. In lakes, however, these characteristic ratios of chemical weathering are altered by algal activity. The lacustrine Si:C atomic ratio is negative feedback regulation by phytoplankton, which may result in this ratio in algal assemblages similar to that in water column. And this regulation suggests lacustrine photosynthetic C fixation in this equilibrium state is quantitative and depends on the DSi concentration. These findings provide new insights into the role of freshwaters in global C and Si biogeochemical cycles.

  5. Coupling of carbon and silicon geochemical cycles in rivers and lakes

    Science.gov (United States)

    Wang, Baoli; Liu, Cong-Qiang; Maberly, Stephen C.; Wang, Fushun; Hartmann, Jens

    2016-10-01

    Carbon (C) and silicon (Si) biogeochemical cycles are important factors in the regulation of atmospheric CO2 concentrations and hence climate change. Theoretically, these elements are linked by chemical weathering and organism stoichiometry, but this coupling has not been investigated in freshwaters. Here we compiled data from global rivers and lakes in the United States of America and the United Kingdom, in order to characterize the stoichiometry between the biogeochemical cycles of C and Si. In rivers this coupling is confirmed by a significant relationship between HCO3-/Na+ and DSi/Na+, and DSi:HCO3- ratio can reflect the mineral source of chemical weathering. In lakes, however, these characteristic ratios of chemical weathering are altered by algal activity. The lacustrine Si:C atomic ratio is negative feedback regulation by phytoplankton, which may result in this ratio in algal assemblages similar to that in water column. And this regulation suggests lacustrine photosynthetic C fixation in this equilibrium state is quantitative and depends on the DSi concentration. These findings provide new insights into the role of freshwaters in global C and Si biogeochemical cycles.

  6. A new biogeochemical model to simulate regional scale carbon emission from lakes, ponds and wetlands

    Science.gov (United States)

    Bayer, Tina; Brakebusch, Matthias; Gustafsson, Erik; Beer, Christian

    2016-04-01

    Small aquatic systems are receiving increasing attention for their role in global carbon cycling. For instance, lakes and ponds in permafrost are net emitters of carbon to the atmosphere, and their capacity to process and emit carbon is significant on a landscape scale, with a global flux of 8-103 Tg methane per year which amounts to 5%-30% of all natural methane emissions (Bastviken et al 2011). However, due to the spatial and temporal highly localised character of freshwater methane emissions, fluxes remain poorly qualified and are difficult to upscale based on field data alone. While many models exist to model carbon cycling in individual lakes and ponds, we perceived a lack of models that can work on a larger scale, over a range of latitudes, and simulate regional carbon emission from a large number of lakes, ponds and wetlands. Therefore our objective was to develop a model that can simulate carbon dioxide and methane emission from freshwaters on a regional scale. Our resulting model provides an additional tool to assess current aquatic carbon emissions as well as project future responses to changes in climatic drivers. To this effect, we have combined an existing large-scale hydrological model (the Variable Infiltration Capacity Macroscale Hydrologic Model (VIC), Liang & Lettenmaier 1994), an aquatic biogeochemical model (BALTSEM, Savchuk et al., 2012; Gustafsson et al., 2014) and developed a new methane module for lakes. The resulting new process-based biogeochemical model is designed to model aquatic carbon emission on a regional scale, and to perform well in high-latitude environments. Our model includes carbon, oxygen and nutrient cycling in lake water and sediments, primary production and methanogenesis. Results of calibration and validation of the model in two catchments (Torne-Kalix in Northern Sweden and of a large arctic river catchment) will be presented.

  7. Effects of ambient water quality on the endangered Lost River sucker in Upper Klamath Lake, Oregon

    Science.gov (United States)

    Martin, B.A.; Saiki, M.K.

    1999-01-01

    Populations of the Lost River sucker Deltistes luxatus have declined so precipitously in the Upper Klamath Basin of Oregon and California that this fish was recently listed for federal protection as an endangered species. Although Upper Klamath Lake is a major refuge for this species, fish in the lake occasionally experience mass mortalities during summer and early fall. This field study was implemented to determine if fish mortalities resulted from degraded water quality conditions associated with seasonal blooms of phytoplankton, especially Aphanizomenon flos-aquae. Our results indicated that fish mortality did not always increase as water temperature, pH, and un-ionized ammonia concentration increased in Upper Klamath Lake. Little or no mortality occurred when these water quality variables attained their maximum values. On the other hand, an inverse relation existed between fish mortality and dissolved oxygen concentration. High mortality (>90%) occurred whenever dissolved oxygen concentrations decreased to 1.05 mg/L, whereas mortality was usually low (< 10%) when dissolved oxygen concentrations equaled or exceeded 1.58 mg/L. Stepwise logistic regression also indicated that the minimum concentration of dissolved oxygen measured was the single most important determinant of fish mortality.

  8. Variability of rainfall over Lake Kariba catchment area in the Zambezi river basin, Zimbabwe

    Science.gov (United States)

    Muchuru, Shepherd; Botai, Joel O.; Botai, Christina M.; Landman, Willem A.; Adeola, Abiodun M.

    2016-04-01

    In this study, average monthly and annual rainfall totals recorded for the period 1970 to 2010 from a network of 13 stations across the Lake Kariba catchment area of the Zambezi river basin were analyzed in order to characterize the spatial-temporal variability of rainfall across the catchment area. In the analysis, the data were subjected to intervention and homogeneity analysis using the Cumulative Summation (CUSUM) technique and step change analysis using rank-sum test. Furthermore, rainfall variability was characterized by trend analysis using the non-parametric Mann-Kendall statistic. Additionally, the rainfall series were decomposed and the spectral characteristics derived using Cross Wavelet Transform (CWT) and Wavelet Coherence (WC) analysis. The advantage of using the wavelet-based parameters is that they vary in time and can therefore be used to quantitatively detect time-scale-dependent correlations and phase shifts between rainfall time series at various localized time-frequency scales. The annual and seasonal rainfall series were homogeneous and demonstrated no apparent significant shifts. According to the inhomogeneity classification, the rainfall series recorded across the Lake Kariba catchment area belonged to category A (useful) and B (doubtful), i.e., there were zero to one and two absolute tests rejecting the null hypothesis (at 5 % significance level), respectively. Lastly, the long-term variability of the rainfall series across the Lake Kariba catchment area exhibited non-significant positive and negative trends with coherent oscillatory modes that are constantly locked in phase in the Morlet wavelet space.

  9. The formation and maintenance of single-thread tie channels entering floodplain lakes: observations from three diverse river systems

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, Joel C [Los Alamos National Laboratory; Dietrich, William E [UC BERKELEY; Day, Geoff [NEWCREST MINING; Parker, Gary [UNIV OF ILLINOIS

    2009-01-01

    Tie channels connect rivers to floodplain lakes on many lowland rivers and thereby play a central role in floodplain sedimentology and ecology, yet they are generally unrecognized and little studied. here we report the results of field studies focused on tie channel origin and morphodynamics in three contrasting systems: the Middle Fly River, Papua New Guinea, the Lower Mississippi River, and Birch Creek in Alaska. Across these river systems, tie channels vary by an order of magnitude in size but exhibit the same characteristic morphology and appear to develop and evolve by a similar set of processes. In all three systems, the channels are characterized by a narrow, leveed single-thread morphology with maximum width approximately one tenth the width of the mainstem river. The channels typically have a V shaped cross-section, unlike most fluvial channels. These channels develop as lakes become isolated from the river by sedimentation. Narrowing of the connection between river and lake causes a sediment-laden jet to develop. Levees develop along the margins of the jet leading to channel emergence and eventual levee aggradation to the height of the mainstem levees. Bi-directional flow in these channels is common. Outflows from the lake scour sediment and prevent channel blockage. We propose that channel geometry and size are then controlled by a dynamic balance between channel narrowing by suspended sediment deposition and incision and widening by mass failure of banks during outflows. Tie channels are laterally stable and may convey flow for hundreds to a few thousand of years.

  10. 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

  11. Modern (1992–2011) and projected (2012–99) peak snowpack and May–July runoff for the Fort Peck Lake and Lake Sakakawea watersheds in the Upper Missouri River Basin

    Science.gov (United States)

    Stamm, John F.; Todey, Dennis; Mayes Bousted, Barbara; Rossi, Shawn; Norton, Parker A.; Carter, Janet M.

    2016-02-09

    Mountain snowpack is an important contributor to runoff in the Upper Missouri River Basin; for example, high amounts of winter and spring precipitation in the mountains and plains in 2010–11 were associated with the peak runoff of record in 2011 in the Upper Missouri River Basin. To project trends in peak mountain snowpack and runoff in the upcoming decades, multiple linear regression models of peak mountain snowpack and total May–July runoff were developed for the Fort Peck Lake (above Fort Peck Dam) and lower Lake Sakakawea watersheds (between Fort Peck and Garrison Dams) in the Upper Missouri River Basin. Input to regression models included seasonal estimates of precipitation, air temperature, and total reference evapotranspiration stratified by elevation. Calibration was based on records from 107 weather stations from 1991 to 2011. Regressed annual peak mountain snowpack was used as input to the transfer function of May–July runoff. Peak snowpack and May–July runoff were projected for 2012–99 on the basis of air temperature and precipitation from the Community Climate System Model (CCSM) output. Two estimates of projected peak snowpack and May–July runoff for 2012–99 were computed: one estimate was based on output from the CCSM, version 3.0 (CCSM3), and the second estimate was based on output from the CCSM, version 4.0 (CCSM4). The significance of projected trends was based on the Kendall’s tau nonparametric test.

  12. MODEL OF CALCULATING WATER QUANTITY NEEDED TO DILUTE AND PURIFY POLLUTANTS IN RIVER NETWORK AND ITS APPLICATIONS

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; WANG Pei-fang

    2005-01-01

    Based on the analysis of dilution capacity and self-purification capacity of water body, the dilution, dispersion, entrapping and purification principles of pollutants in river system at river network area were discussed in this paper. Also, the one and two dimensional models of water quantity needed for improving water environment quality and pollutant concentrations were developed for rivers and lakes respectively. The calculation method for the quantity of water transfer was given and the forecasting evaluation of the effect of water transfer was carried out. It was took the project, water transfer from Yangtze River to improve the water quality of rivers in Zhangjiagang City, as an example, and changing principles of water quantity and quality were observed in rivers and lakes through site water transfer experiments. The theory of estimating parameters in inverse problem was used to determine parameters in water quantity and quality models. The water quantity and quality coupled models in river system were applied to calculate the minimal water transfer quantity. The theoretical and technical support for the improvement of water environmental quality in Zhangjiagang City and the project "water transfer form Yangtze River to Taihu Lake" were provided.

  13. Viruses and bacteria in floodplain lakes along a major Amazon tributary respond to distance to the Amazon River

    Directory of Open Access Journals (Sweden)

    Rafael Marques Almeida

    2015-03-01

    Full Text Available Because of the massive water volume of the Amazon River, the Amazon tributaries have their water backed up by hundreds of kilometers upstream their mouth. This backwater effect is part of the complex hydrodynamics of Amazonian surface waters, which in turn drives the variation in concentrations of organic matter and nutrients, and also regulates planktonic communities such as viruses and bacteria. Viruses and bacteria are commonly tightly coupled, and their ecological role in aquatic food webs has been increasingly recognized. Here, we surveyed viral and bacterial abundances in 26 floodplain lakes along the Trombetas River, the largest clear-water tributary of the Amazon River’s north margin. We correlated viral and bacterial abundances with temperature, pH, dissolved inorganic carbon, dissolved organic carbon (DOC, phosphorus, nitrogen, turbidity, water transparency, partial pressure of carbon dioxide (pCO2, phytoplankton abundance and distance from the lake mouth until the confluence of the Trombetas with the Amazon River. We hypothesized that both bacterial and viral abundances would change along a latitudinal gradient, as the backwater effect becomes more intense with increased proximity to the Amazon River; different flood duration and intensity among lakes and waters with contrasting sources would cause spatial variation. Our measurements were performed during the low water period, when floodplain lakes are in their most lake-like conditions. Viral and bacterial abundances, DOC, pCO2 and water transparency increased as distance to the Amazon River increased. Most viruses were bacteriophages, as viruses were strongly linked to bacteria, but not to phytoplankton. We suggest that bacterial abundances increase in response to DOC quantity and possibly quality, consequently leading to increased viral abundances. Our results highlight that hydrodynamics plays a key role in the regulation of planktonic viral and bacterial communities in

  14. LakeMIP Kivu: evaluating the representation of a large, deep tropical lake by a set of one-dimensional lake models

    Directory of Open Access Journals (Sweden)

    WIM Thiery

    2014-02-01

    Full Text Available The African great lakes are of utmost importance for the local economy (fishing, as well as being essential to the survival of the local people. During the past decades, these lakes experienced fast changes in ecosystem structure and functioning, and their future evolution is a major concern. In this study, for the first time a set of one-dimensional lake models are evaluated for Lake Kivu (2.28°S; 28.98°E, East Africa. The unique limnology of this meromictic lake, with the importance of salinity and subsurface springs in a tropical high-altitude climate, presents a worthy challenge to the seven models involved in the Lake Model Intercomparison Project (LakeMIP. Meteorological observations from two automatic weather stations are used to drive the models, whereas a unique dataset, containing over 150 temperature profiles recorded since 2002, is used to assess the model's performance. Simulations are performed over the freshwater layer only (60 m and over the average lake depth (240 m, since salinity increases with depth below 60 m in Lake Kivu and some lake models do not account for the influence of salinity upon lake stratification. All models are able to reproduce the mixing seasonality in Lake Kivu, as well as the magnitude and seasonal cycle of the lake enthalpy change. Differences between the models can be ascribed to variations in the treatment of the radiative forcing and the computation of the turbulent heat fluxes. Fluctuations in wind velocity and solar radiation explain inter-annual variability of observed water column temperatures. The good agreement between the deep simulations and the observed meromictic stratification also shows that a subset of models is able to account for the salinity- and geothermal-induced effects upon deep-water stratification. Finally, based on the strengths and weaknesses discerned in this study, an informed choice of a one-dimensional lake model for a given research purpose becomes possible.

  15. Fish larvae assemblages in two floodplain lakes with different degrees of connection to the Paraná River, Brazil

    Directory of Open Access Journals (Sweden)

    Vanessa Salete Daga

    Full Text Available The objective of this study was to assess the abundance, attributes of assemblages, and spatial and temporal distributions of fish larvae and their relationships with some abiotic variables in two floodplain lakes with different degrees of connection to the Paraná River in Ilha Grande National Park, PR, Brazil. Four sampling sites were chosen, two in each floodplain lake. Night samples were taken with plankton nets during three spawning seasons (monthly, from October to March from 2001 to 2005. The highest diversity and abundance were recorded at Saraiva Lake, with 25 taxa being identified. In Xambrê Lake, only sedentary species were captured, and the most abundant species were Plagioscion squamosissimus and Hypophthalmus edentatus. The greatest abundance of larvae was found in the second spawning season. In the Saraiva Lake, the most abundant species were Moenkhausia aff. intermedia, Hyphessobrycon sp., and Bryconamericus stramineus, but larvae of known migratory species were also documented. In this lake, the greatest abundance of larvae was found in the third spawning. Larvae abundance was influenced by water temperature and conductivity. The high diversity and abundance recorded in Saraiva Lake may be a result of its connectivity with the Paraná River, and the low diversity and abundance observed at Xambrê Lake are likely due to its isolation from the river. This work shows the importance of these lagoons for fish development, for both sedentary and migratory species. Both lagoons may be considered to have extreme ecological importance and they are also extremely susceptible to impacts, so any careless disturbance may cause irreversible damage.

  16. Simulation of Lake Victoria Circulation Patterns Using the Regional Ocean Modeling System (ROMS).

    Science.gov (United States)

    Nyamweya, Chrispine; Desjardins, Christopher; Sigurdsson, Sven; Tomasson, Tumi; Taabu-Munyaho, Anthony; Sitoki, Lewis; Stefansson, Gunnar

    2016-01-01

    Lake Victoria provides important ecosystem services including transport, water for domestic and industrial uses and fisheries to about 33 million inhabitants in three East African countries. The lake plays an important role in modulating regional climate. Its thermodynamics and hydrodynamics are also influenced by prevailing climatic and weather conditions on diel, seasonal and annual scales. However, information on water temperature and circulation in the lake is limited in space and time. We use a Regional Oceanographic Model System (ROMS) to simulate these processes from 1st January 2000 to 31st December 2014. The model is based on real bathymetry, river runoff and atmospheric forcing data using the bulk flux algorithm. Simulations show that the water column exhibits annual cycles of thermo-stratification (September-May) and mixing (June-August). Surface water currents take different patterns ranging from a lake-wide northward flow to gyres that vary in size and number. An under flow exists that leads to the formation of upwelling and downwelling regions. Current velocities are highest at the center of the lake and on the western inshore waters indicating enhanced water circulation in those areas. However, there is little exchange of water between the major gulfs (especially Nyanza) and the open lake, a factor that could be responsible for the different water quality reported in those regions. Findings of the present study enhance understanding of the physical processes (temperature and currents) that have an effect on diel, seasonal, and annual variations in stratification, vertical mixing, inshore-offshore exchanges and fluxes of nutrients that ultimately influence the biotic distribution and trophic structure. For instance information on areas/timing of upwelling and vertical mixing obtained from this study will help predict locations/seasons of high primary production and ultimately fisheries productivity in Lake Victoria.

  17. Simulation of Lake Victoria Circulation Patterns Using the Regional Ocean Modeling System (ROMS.

    Directory of Open Access Journals (Sweden)

    Chrispine Nyamweya

    Full Text Available Lake Victoria provides important ecosystem services including transport, water for domestic and industrial uses and fisheries to about 33 million inhabitants in three East African countries. The lake plays an important role in modulating regional climate. Its thermodynamics and hydrodynamics are also influenced by prevailing climatic and weather conditions on diel, seasonal and annual scales. However, information on water temperature and circulation in the lake is limited in space and time. We use a Regional Oceanographic Model System (ROMS to simulate these processes from 1st January 2000 to 31st December 2014. The model is based on real bathymetry, river runoff and atmospheric forcing data using the bulk flux algorithm. Simulations show that the water column exhibits annual cycles of thermo-stratification (September-May and mixing (June-August. Surface water currents take different patterns ranging from a lake-wide northward flow to gyres that vary in size and number. An under flow exists that leads to the formation of upwelling and downwelling regions. Current velocities are highest at the center of the lake and on the western inshore waters indicating enhanced water circulation in those areas. However, there is little exchange of water between the major gulfs (especially Nyanza and the open lake, a factor that could be responsible for the different water quality reported in those regions. Findings of the present study enhance understanding of the physical processes (temperature and currents that have an effect on diel, seasonal, and annual variations in stratification, vertical mixing, inshore-offshore exchanges and fluxes of nutrients that ultimately influence the biotic distribution and trophic structure. For instance information on areas/timing of upwelling and vertical mixing obtained from this study will help predict locations/seasons of high primary production and ultimately fisheries productivity in Lake Victoria.

  18. Algal community composition and abundance near the confluence of the Jialing and Yangtze Rivers and in Shuanglong Lake in Chongqing, P.R.China

    Institute of Scientific and Technical Information of China (English)

    GUO Wei-hua; HE Dong-cai; LONG Tian-yu; LI Nan; DAI Ling-ling

    2008-01-01

    To understand the potential impact of the Three Gorges Reservoir on the aquatic ecosystem after the damming of the Yangtze River, we studied the community composition and temporal abundance distribution of algae in two types of water bodies:a segment of the Jialing River near its confluence with the Yangtze River as an example of the river-lake type, and Shuanglong Lake in Chongqing as an example of the lake type. In total, 107 species belonging to 58 genera of 7 phyla were identified in the study area of the Jialing River, dominated by three groups with 49.5% diatoms, 29.0% chlorophytes, and 11.4% cyanobacteria in the community composition. There were 122 species belonging to 66 genera of 8 phyla in Shuanglong Lake, dominated by the same three groups with 19.7% diatoms, 48.4% chlorophytes, and 22.2% cyanobacteria. The densities of total algae and individual dominant groups were all much higher in the lake. More species of diatoms were found in the river-lake segment; whereas more chlorophyte species and cyanobacteriaum species were in the lake. There were 17 dominant species including 8 diatoms, 4 chlorophytes, 3 cyanobacteria and 2 cryptophytes in the river-lake segment, and 21 species in the lake, including 2 diatoms, 9 chlorophytes, 6 cyanobacteria, 3 cryptophytes and a dinoflagellate. In eutrophic conditions, chlorophytes and cyanobacteria mayproliferate in a lake-type area and diatoms may cause algal bloom in a relatively faster-flow lake-river type area.

  19. Determining lake surface water temperatures (LSWTs worldwide using a tuned 1-dimensional lake model (FLake, v1

    Directory of Open Access Journals (Sweden)

    A. Layden

    2015-10-01

    Full Text Available FLake, a 1-dimensional freshwater lake model, is tuned for 244 globally distributed large lakes using lake surface water temperatures (LSWTs derived from Along-Track Scanning Radiometers (ATSRs. The model, tuned using only 3 lake properties; lake depth, albedo (snow and ice and light extinction co-efficient, substantially improves the measured biases in various features of the LSWT annual cycle, including the LSWTs of saline and high altitude lakes. The daily mean absolute differences (MAD and the spread of differences (±2 standard deviations across the trial seasonally ice covered lakes (lakes with a lake-mean LSWT remaining below 1 °C for part of the annual cycle is reduced from 3.01± 2.25 °C (pre-tuning to 0.84 ± 0.51 °C (post-tuning. For non-seasonally ice-covered trial lakes (lakes with a lake-mean LSWT remaining above 1 °C throughout its annual cycle, the average daily mean absolute difference (MAD is reduced from 3.55 ± 3.20 °C to 0.96 ± 0.63 °C. The post tuning results for the trial lakes (35 lakes are highly representative of the post tuning results of the 244 lakes. The sensitivity of the summer LSWTs of deeper lakes to changes in the timing of ice-off is demonstrated. The modelled summer LSWT response to changes in ice-off timing is found to be strongly affected by lake depth and latitude, explaining 0.50 (R2adj, p = 0.001 of the inter-lake variance in summer LSWTs. Lake depth alone explains 0.35 (p =0.003 of the variance. The tuning approach undertaken in this study, overcomes the obstacle of the lack of available lake characteristic information (snow and ice albedo and light extinction co-efficient for individual lakes. Furthermore, the tuned values for lake depth, snow and ice albedo and light extinction co-efficient for the 244 lakes provide guidance for improving LSWTs modelling in FLake.

  20. On the Changes of the Hydrological Balance of Caribbean Lakes - Modeling and Observations

    Science.gov (United States)

    Comarazamy, D.; Gonzalez, J.; Glenn, E.; Leon, Y.; Brito, D. R.

    2013-05-01

    The Enriquillo and Sumatra are saltwater lakes located in a rift valley that is a former marine strait created around 1 million years ago when the water level fell and the strait was filled in by river sediments, they are the largest lakes in the Dominican Republic and Haiti, respectively, with Lake Enriquillo being the lowest point in the Caribbean. The lakes, part of the Enriquillo closed water basin in the southwestern region of the island of La Hispaniola, have been experiencing dramatic changes in total lake-surface area coverage during the period 1980-2012. The size of the lakes was determined using remote sensing images (NASA-LANDSAT) analyzed with geographic information system (GIS) at different times during the available record. The size calculation for Lake Enriquillo shows a lake surface area of approximately 276 km2 in 1984 that gradually decreased to 172 km2 in 1996. After a period of fluctuations between 1996 and 2001, the surface area of the lake reaches its lowest point in 2004, at 165 km2. Beginning in 2004, the recent growth of the lake begins and reaches its 1984 size in 2006. Based on surface area measurement for December 2009, the lake size is 333 km2, 17% larger than in 1984 and almost double than in 2004. Sumatra sizes at both ends of the record are 115.96 km2 in 1984 and 134.26 km2 in 2011, an overall 15.8% increase in 27 years. Because the lakes are mostly latitudinally restricted by topography, most of the size changes occur on the southeastern side of Lake Enriquillo, with some growth on the western tip. Determining the causes of lake surface area changes is of extreme importance due to the environmental, social, and economic consequences. The goal of this study is to quantify the changing water balance in these lakes using satellite and ground observations and regional atmospheric modeling. Analyses of environmental variables in the region reflect a hydrological unbalance of the lakes due to changing regional hydro-climatic conditions

  1. Glacial lakes in the Indian Himalayas--from an area-wide glacial lake inventory to on-site and modeling based risk assessment of critical glacial lakes.

    Science.gov (United States)

    Worni, Raphael; Huggel, Christian; Stoffel, Markus

    2013-12-01

    Glacial lake hazards and glacial lake distributions are investigated in many glaciated regions of the world, but comparably little attention has been given to these topics in the Indian Himalayas. In this study we present a first area-wide glacial lake inventory, including a qualitative classification at 251 glacial lakes >0.01 km(2). Lakes were detected in the five states spanning the Indian Himalayas, and lake distribution pattern and lake characteristics were found to differ significantly between regions. Three glacial lakes, from different geographic and climatic regions within the Indian Himalayas were then selected for a detailed risk assessment. Lake outburst probability, potential outburst magnitudes and associated damage were evaluated on the basis of high-resolution satellite imagery, field assessments and through the use of a dynamic model. The glacial lakes analyzed in the states of Jammu and Kashmir and Himachal Pradesh were found to present moderate risks to downstream villages, whereas the lake in Sikkim severely threatens downstream locations. At the study site in Sikkim, a dam breach could trigger drainage of ca. 16×10(6)m(3) water and generate maximum lake discharge of nearly 7000 m(3) s(-). The identification of critical glacial lakes in the Indian Himalayas and the detailed risk assessments at three specific sites allow prioritizing further investigations and help in the definition of risk reduction actions.

  2. Effects of water diversion from Yangtze River to Taihu Lake on hydrodynamic regulation of Taihu Lake%引江济太调水工程对太湖水动力的调控效果

    Institute of Scientific and Technical Information of China (English)

    郝文彬; 唐春燕; 滑磊; ACHARYA Kumud

    2012-01-01

    为研究引江济太调水工程对太湖水动力调控所产生的效果,采用数学模型对其水动力进行模拟.利用环境流体动力学模型(EFDC模型),以湖体水龄(描述湖泊水体交换速率的参数)为研究 对象,系统地研究引江济太调水工程对太湖水动力的调控情况.结果表明:(a)引江济太调水工程对太湖湖体水动力过程的作用效果很大程度上取决于风速、风向以及出入湖的流量;(b)太湖湖体水龄的分布具有很强的时空异质性,夏天的平均水龄约为130 d,其他季节的平均水龄约为230 d;(c)太湖地区夏天的主导风向——东南风能够促进东部湖区(无锡、苏州水源地所在地)和梅梁湾湖区(太湖重污染区)的水交换,改善水体运动条件;(d)望虞河入湖的最经济调水流量为100m3/s.%To study the effects of a water diversion project from the Yangtze River to Taihu Lake on the hydrodynamic regulation of Taihu Lake, mathematical models were used to simulate the hydrodynamic process. With the water age of the lake being the research focus, the hydrodynamic regulation of Taihu Lake by the project was systematically studied using the environmental fluid dynamics code (EFDC) model. The results show the following: (a) The effects of water diversion from the Yangtze River to Taihu Lake on the hydrodynamic process in Taihu Lake were mainly determined by wind velocity, wind direction, and inflow of the lake, (b) The water age of Taihu Lake presented significant spatial and temporal heterogeneity, with a mean water age of approximately 130 days in the summer and 230 days in other seasons, ? The dominant southeastly wind of the summer greatly enhanced the transport of the transferred water into the eastern lake area (the drinking water source area of Wuxi and Suzhou cities) and Meiliang Bay (a seriously polluted area of Taihu Lake), and improved water movement conditions in these areas, (d) The most efficient discharge of the

  3. Computational Modeling of Pollution Transmission in Rivers

    Science.gov (United States)

    Parsaie, Abbas; Haghiabi, Amir Hamzeh

    2017-06-01

    Modeling of river pollution contributes to better management of water quality and this will lead to the improvement of human health. The advection dispersion equation (ADE) is the government equation on pollutant transmission in the river. Modeling the pollution transmission includes numerical solution of the ADE and estimating the longitudinal dispersion coefficient (LDC). In this paper, a novel approach is proposed for numerical modeling of the pollution transmission in rivers. It is related to use both finite volume method as numerical method and artificial neural network (ANN) as soft computing technique together in simulation. In this approach, the result of the ANN for predicting the LDC was considered as input parameter for the numerical solution of the ADE. To validate the model performance in real engineering problems, the pollutant transmission in Severn River has been simulated. Comparison of the final model results with measured data of the Severn River showed that the model has good performance. Predicting the LDC by ANN model significantly improved the accuracy of computer simulation of the pollution transmission in river.

  4. Modeling a glacial lake outburst flood process chain: the case of Lake Palcacocha and Huaraz, Peru

    Science.gov (United States)

    Somos-Valenzuela, Marcelo A.; Chisolm, Rachel E.; Rivas, Denny S.; Portocarrero, Cesar; McKinney, Daene C.

    2016-07-01

    One of the consequences of recent glacier recession in the Cordillera Blanca, Peru, is the risk of glacial lake outburst floods (GLOFs) from lakes that have formed at the base of retreating glaciers. GLOFs are often triggered by avalanches falling into glacial lakes, initiating a chain of processes that may culminate in significant inundation and destruction downstream. This paper presents simulations of all of the processes involved in a potential GLOF originating from Lake Palcacocha, the source of a previously catastrophic GLOF on 13 December 1941, killing about 1800 people in the city of Huaraz, Peru. The chain of processes simulated here includes (1) avalanches above the lake; (2) lake dynamics resulting from the avalanche impact, including wave generation, propagation, and run-up across lakes; (3) terminal moraine overtopping and dynamic moraine erosion simulations to determine the possibility of breaching; (4) flood propagation along downstream valleys; and (5) inundation of populated areas. The results of each process feed into simulations of subsequent processes in the chain, finally resulting in estimates of inundation in the city of Huaraz. The results of the inundation simulations were converted into flood intensity and preliminary hazard maps (based on an intensity-likelihood matrix) that may be useful for city planning and regulation. Three avalanche events with volumes ranging from 0.5 to 3 × 106 m3 were simulated, and two scenarios of 15 and 30 m lake lowering were simulated to assess the potential of mitigating the hazard level in Huaraz. For all three avalanche events, three-dimensional hydrodynamic models show large waves generated in the lake from the impact resulting in overtopping of the damming moraine. Despite very high discharge rates (up to 63.4 × 103 m3 s-1), the erosion from the overtopping wave did not result in failure of the damming moraine when simulated with a hydro-morphodynamic model using excessively conservative soil

  5. Taking Teachers from the River to the Coast: a COSEE Great Lakes and Lake Superior NERR Collaboration

    Science.gov (United States)

    The Center for Ocean Sciences Education Excellence (COSEE) Great Lakes Shipboard and Shoreline Science Workshop provides 15 formal and informal educators of G5-10 an opportunity to spend a week aboard the US EPA’s 180’ R/V Lake Guardian working side-by-side with Great Lakes scien...

  6. Waco Lake, Bosque River, Texas, Brazos River and Tributaries, Texas. Embankment Criteria, Performance and Foundation Report

    Science.gov (United States)

    1990-01-01

    Bosque, Leon and Little Rivers being major tributaries. b. StratiQraphy. Ranging from west to east, geologic formations cropping out include limestones...pore pressure assumptiops were based on the re-evaluation of piezometers and the observed upward excess gra- dients within the Pepper Formation. "S...ft t IXE 1 2 £3 150£ :77, (CL) I.0 -C SUMARYOS OMPCTIN TSTSI l2d0& 4310 A9~ TANDRD ASHO oVAI~ /Jr3 n .flC~tvA flC*Y .Tr.4 to COMACO TESi REOR fa,-.Ec

  7. Analysis of regional rainfall-runoff parameters for the Lake Michigan Diversion hydrological modeling

    Science.gov (United States)

    Soong, David T.; Over, Thomas M.

    2015-01-01

    The Lake Michigan Diversion Accounting (LMDA) system has been developed by the U.S. Army Corps of Engineers, Chicago District (USACE-Chicago) and the State of Illinois as a part of the interstate Great Lakes water regulatory program. The diverted Lake Michigan watershed is a 673-square-mile watershed that is comprised of the Chicago River and Calumet River watersheds. They originally drained into Lake Michigan, but now flow to the Mississippi River watershed via three canals constructed in the Chicago area in the early twentieth century. Approximately 393 square miles of the diverted watershed is ungaged, and the runoff from the ungaged portion of the diverted watershed has been estimated by the USACE-Chicago using the Hydrological Simulation Program-FORTRAN (HSPF) program. The accuracy of simulated runoff depends on the accuracy of the parameter set used in the HSPF program. Nine parameter sets comprised of the North Branch, Little Calumet, Des Plaines, Hickory Creek, CSSC, NIPC, 1999, CTE, and 2008 have been developed at different time periods and used by the USACE-Chicago. In this study, the U.S. Geological Survey and the USACE-Chicago collaboratively analyzed the parameter sets using nine gaged watersheds in or adjacent to the diverted watershed to assess the predictive accuracies of selected parameter sets. Six of the parameter sets, comprising North Branch, Hickory Creek, NIPC, 1999, CTE, and 2008, were applied to the nine gaged watersheds for evaluating their simulation accuracy from water years 1996 to 2011. The nine gaged watersheds were modeled by using the three LMDA land-cover types (grass, forest, and hydraulically connected imperviousness) based on the 2006 National Land Cover Database, and the latest meteorological and precipitation data consistent with the current (2014) LMDA modeling framework.

  8. Seasonal baseline of nutrients and stable isotopes in a saline lake of Argentina: biogeochemical processes and river runoff effects.

    Science.gov (United States)

    Kopprio, Germán A; Kattner, Gerhard; Freije, R Hugo; de Paggi, Susana José; Lara, Rubén J

    2014-05-01

    The seasonal variability of inorganic and organic nutrients and stable isotopes and their relations with plankton and environmental conditions were monitored in Lake Chasicó. Principal component analysis evidenced the strong influence of the river runoff on several biogeochemical variables. Silicate concentrations were controlled by diatom biomass and river discharge. Higher values of nitrate and soluble reactive phosphorus (SRP) indicated agricultural uses in the river basin. Elevated pH values (∼ 9) inhibiting nitrification in the lake explained partially the dominance of ammonium: ∼ 83 % of dissolved inorganic nitrogen (DIN). The low DIN/SRP ratio inferred nitrogen limitation, although the hypotheses of iron and CO2 limitation are relevant in alkaline lakes. Particulate organic matter (POM) and dissolved organic matter (DOM) were mainly of autochthonous origin. The main allochthonous input was imported by the river as POM owning to the arid conditions. Dissolved organic carbon was likely top-down regulated by the bacterioplankton grazer Brachionus plicatilis. The δ(13)C signature was a good indicator of primary production and its values were influenced probably by CO2 limitation. The δ(15)N did not evidence nitrogen fixation and suggested the effects of anthropogenic activities. The preservation of a good water quality in the lake is crucial for resource management.

  9. 76 FR 336 - Notice of NEPA Public Scoping Meeting Information for the Great Lakes and Mississippi River...

    Science.gov (United States)

    2011-01-04

    ... conducting a feasibility study of the options and technologies that could be applied to prevent aquatic.... Thursday, February 10, 2011: Vicksburg Convention Center, 1600 Mulberry Street, Vicksburg, MS. Please see... Lakes and Mississippi River Interbasin Study (``GLMRIS'') AGENCY: Department of the Army, U.S. Army...

  10. Identification of the glaciers and mountain naturally dammed lakes in the Pskem, the Kashkadarya and the Surhandarya River basins, Uzbekistan, using ALOS satellite data

    Directory of Open Access Journals (Sweden)

    Eleonora Semakova

    2016-05-01

    Full Text Available The glacierized area of Uzbekistan is represented in three river basins – the Pskem, the Kashkadarya and the Surhandarya. This study considers the present state of the glaciers and high-mountain lakes distribution in this area based on the analysis and validation of advanced land observing satellite (ALOS/advanced visible and near infrared radiometer type 2 (AVNIR-2 satellite data. Between the 1960s and the 2010s, the glacierized area decreased by 23% in the Pskem River basin (including the Maydantal, by 49% in the Kashkadarya and by 40% in the Surhandarya (including the Sangardak and the Tupalang River basins. The retreat fairly slowed in the 1980s–2010s. There are 75 glacial lakes and 35 rock-dammed lakes (including landslide-dammed ones in the Pskem River basin, 45% of all the lakes covering the area less than 0.002 km2; 13 glacial lakes and 4 rock-dammed lakes in the Kashkadarya and 34 glacial lakes and 16 rock-dammed lakes in the Surhandarya River basins. The landslide rock-dammed Ikhnach Upper Lake lost 0.04 km2 in size from 1 August 2010 to 30 August 2010 because of the seepage through the rock dam and 0.10 km2 from 1 August to 18 October 2013.

  11. Modeling Antarctic subglacial lake filling and drainage cycles

    Directory of Open Access Journals (Sweden)

    C. F. Dow

    2015-11-01

    Full Text Available The growth and drainage of active subglacial lakes in Antarctica has previously been inferred from analysis of ice surface altimetry data. We use a subglacial hydrology model applied to a synthetic Antarctic ice stream to determine internal controls on the filling and drainage of subglacial lakes and their impact on ice stream dynamics. Our model outputs suggest that the highly constricted subglacial environment of the ice stream, combined with relatively high rates of water flow funneled from large catchments, can combine to create a system exhibiting slow-moving pressure waves. Over a period of years, the accumulation of water in the ice stream onset region results in a buildup of pressure creating temporary channels, which then evacuate the excess water. This increased flux of water through the ice stream drives lake growth. As the water body builds up, it too steepens the hydraulic gradient and allows greater flux out of the overdeepened lake basin. Eventually this flux is large enough to create channels that cause the lake to drain. Due to the presence of the channels, the drainage of the lake causes high water pressures around 50 km downstream of the lake rather than immediately in the vicinity of the overdeepening. Following lake drainage, channels again shut down. Lake drainage depends on the internal hydrological development in the wider system and therefore does not directly correspond to a particular water volume or depth. This creates a highly temporally and spatially variable system, which is of interest for assessing the importance of subglacial lakes in ice stream hydrology and dynamics.

  12. Challenges and opportunities for integrating lake ecosystem modelling approaches

    Science.gov (United States)

    Mooij, Wolf M.; Trolle, Dennis; Jeppesen, Erik; Arhonditsis, George; Belolipetsky, Pavel V.; Chitamwebwa, Deonatus B.R.; Degermendzhy, Andrey G.; DeAngelis, Donald L.; Domis, Lisette N. De Senerpont; Downing, Andrea S.; Elliott, J. Alex; Ruberto, Carlos Ruberto; Gaedke, Ursula; Genova, Svetlana N.; Gulati, Ramesh D.; Hakanson, Lars; Hamilton, David P.; Hipsey, Matthew R.; Hoen, Jochem 't; Hulsmann, Stephan; Los, F. Hans; Makler-Pick, Vardit; Petzoldt, Thomas; Prokopkin, Igor G.; Rinke, Karsten; Schep, Sebastiaan A.; Tominaga, Koji; Van Dam, Anne A.; Van Nes, Egbert H.; Wells, Scott A.; Janse, Jan H.

    2010-01-01

    A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others ('reinventing the wheel'). The other challenge is to avoid focusing on only one type of model, while ignoring new and diverse approaches that have become available ('having tunnel vision'). In this paper, we aim at improving the awareness of existing models and knowledge of concurrent approaches in lake ecosystem modelling, without covering all possible model tools and avenues. First, we present a broad variety of modelling approaches. To illustrate these approaches, we give brief descriptions of rather arbitrarily selected sets of specific models. We deal with static models (steady state and regression models), complex dynamic models (CAEDYM, CE-QUAL-W2, Delft 3D-ECO, LakeMab, LakeWeb, MyLake, PCLake, PROTECH, SALMO), structurally dynamic models and minimal dynamic models. We also discuss a group of approaches that could all be classified as individual based: super-individual models (Piscator, Charisma), physiologically structured models, stage-structured models and trait-based models. We briefly mention genetic algorithms, neural networks, Kalman filters and fuzzy logic. Thereafter, we zoom in, as an in-depth example, on the multi-decadal development and application of the lake ecosystem model PCLake and related models (PCLake Metamodel, Lake Shira Model, IPH-TRIM3D-PCLake). In the discussion, we argue that while the historical development of each approach and model is understandable given its 'leading principle', there are many opportunities for combining approaches. We take the point of view that a single 'right' approach does not exist and should not be strived for. Instead, multiple modelling approaches, applied concurrently to a given problem, can help develop an integrative

  13. Escapement Monitoring of Adult Chinook Salmon in the Secesh River and Lake Creek, Idaho, 1999 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Faurot, Dave; Kucera, Paul A. (Nez Perce Tribe, Lapwai, ID)

    2001-04-01

    Underwater time-lapse video technology was used to monitor adult spring and summer chinook salmon abundance in spawning areas in Lake Creek and the Secesh River, Idaho, in 1999. This technique is a passive methodology that does not trap or handle this Endangered Species Act listed species. This was the third year of testing the remote application of this methodology in the Secesh River drainage. Secesh River chinook salmon represent a wild salmon spawning aggregate that has not been directly supplemented with hatchery fish. Adult chinook salmon spawner abundance was estimated in Lake Creek with the remote time-lapse video application. Adult spawner escapement into Lake Creek in 1999 was 67 salmon. Significant upstream and downstream spawner movement affected the ability to determine the number of fish that contributed to the spawning population. The first passage on Lake Creek was recorded on July 11, two days after installation of the fish counting station. Peak net upstream adult movement occurred at the Lake Creek site on July 20, peak of total movement activity was August 19 with the last fish observed on August 26. A minimum of 133 adult chinook salmon migrated upstream past the Secesh River fish counting station to spawning areas in the Secesh River drainage. The first upstream migrating adult chinook salmon passed the Secesh River site prior to the July 15 installation of the fish counting station. Peak net upstream adult movement at the Secesh River site occurred July 19, peak of total movement was August 15, 17 and 18 and the last fish passed on September 10. Migrating salmon in the Secesh River and Lake Creek exhibited two behaviorally distinct segments of fish movement. Mainly upstream only, movement characterized the first segment. The second segment consisted of upstream and downstream movement with very little net upstream movement. Estimated abundance was compared to single and multiple-pass redd count surveys within the drainage. There were

  14. Runoff modeling of the Mara River using Satellite Observed Soil ...

    African Journals Online (AJOL)

    with European Remote Sensing (ERS) Scatterometer in modeling runoff of the Zambezi river basin. ... (2008) using Geospatial Stream Flow ... obtained for Mara River at Mara mines, Nyangores at Bomet and Amala at Mulot river gauging ...

  15. Geochemistry of the Johnson River, Lake Clark National Park and Preserve, Alaska

    Science.gov (United States)

    Brabets, Timothy P.; Riehle, James R.

    2003-01-01

    The Johnson River Basin, located in Lake Clark National Park and Preserve, drains an area of 96 square miles. A private inholding in the upper part of the basin contains a gold deposit that may be developed in the future. To establish a natural baseline to compare potential effects on water quality if development were to occur, the upper part of the Johnson River Basin was studied from 1999 to 2001 as part of a cooperative study with the National Park Service. Two basic rock types occur within the drainage basin of the study: the Jurassic Talkeetna Formation of interbedded volcanic and volcaniclastic rocks, and the slightly younger plutonic rocks of the Aleutian-Alaska Ranges batholith. The Johnson River gold prospect reflects widespread, secondary mineralization and alteration of the Talkeetna Formation. Metals found at the prospect proper are: arsenic, cadmium, copper, gold, iron, lead, mercury, molybdenum, selenium, silver, and zinc. The Johnson River prospect is located in the East Fork Ore Creek Basin, a 0.5 square mile watershed that is a tributary to the Johnson River. Water quality data from this stream reflect the mineralization of the basin and the highest concentrations of several trace elements and major ions of the water column were found in this stream. Presently, pH in this stream is normal, indicating that there is sufficient buffering capacity. At the Johnson River streamgage, which drains approximately 25 mi2 including the East Fork Ore Creek, concentrations of these constituents are significantly lower, reflecting the runoff from Johnson Glacier and Double Glacier, which account for approximately 75 percent of the total discharge. Streambed concentrations of cadmium, lead, and zinc from East Fork Ore Creek and its receiving stream, Ore Creek, typically exceed concentrations where sediment dwelling organisms would be affected. Similar to the water column chemistry, concentrations of these elements are lower at the Johnson River streamgage

  16. Spatial correlations between urbanization and river water pollution in the heavily polluted area of Taihu Lake Basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Haixia; DUAN Xuejun; Becky STEWART; YOU Bensheng; JIANG Xiaowei

    2013-01-01

    Water pollution in the Taihu Lake Basin has been the focus of attention in China and abroad for a long time,due to its position in the forefront of urban development in China.Based on data gathering and processing from 84 monitoring sections in this heavily polluted area,this study first analyzes spatial patterns of urbanization and the distribution of river water pollution,and then uses the GeoDa bivariate spatial autocorrelation model to investigate the spatial correlation between urbanization and river water pollution at the scale of township units.The results show that urbanization has adverse impacts on water pollution,and the influence varies in different levels of development areas.The urban township units have the highest level of urbanization and highest pollution,but the best water quality; the suburban units have lower level of urbanization,but higher pollution and worse water quality;however the rural units have the lowest level of urbanization and lowest pollution,mainly affected by upstream pollution,but worst water quality.Lastly,urban and rural planning committees,while actively promoting the process of development in the region,should gradually resolve the issue of pollution control lagging behind urban life and urban development,giving priority to construction of centralized sewage treatment facilities and associated pipeline network coverage in the rural areas and suburban areas.

  17. Lake

    Science.gov (United States)

    Wien, Carol Anne

    2008-01-01

    The lake is blue black and deep. It is a glaciated finger lake, clawed out of rock when ice retracted across Nova Scotia in a northerly direction during the last ice age. The lake is narrow, a little over a mile long, and deep, 90 to 190 feet in places according to local lore, off the charts in others. The author loves to swim there, with a sense…

  18. Heavy Metal Pollution, Fractionation, and Potential Ecological Risks in Sediments from Lake Chaohu (Eastern China) and the Surrounding Rivers

    Science.gov (United States)

    Zhang, Lei; Liao, Qianjiahua; Shao, Shiguang; Zhang, Nan; Shen, Qiushi; Liu, Cheng

    2015-01-01

    Heavy metal (Cr, Ni, Cu, Zn, Cd, and Pb) pollution, fractionation, and ecological risks in the sediments of Lake Chaohu (Eastern China), its eleven inflowing rivers and its only outflowing river were studied. An improved BCR (proposed by the European Community Bureau of Reference) sequential extraction procedure was applied to fractionate heavy metals within sediments, a geoaccumulation index was used to assess the extent of heavy metal pollution, and a risk assessment code was applied to evaluate potential ecological risks. Heavy metals in the Shuangqiao and Nanfei Rivers were generally higher than the other studied sites. Of the three Lake Chaohu sites, the highest concentrations were identified in western Chaohu. Heavy metal pollution and ecological risks in the lake’s only outflowing river were similar to those in the eastern region of the lake, to which the river is connected. Heavy metal concentrations occurred in the following order: Cd > Zn > Cu > Pb ≈ Ni ≈ Cr. Cr, Ni, and Cu made up the largest proportion of the residual fraction, while Cd was the most prominent metal in the exchangeable and carbonate-included fraction. Cd posed the greatest potential ecological risk; the heavy metals generally posed risks in the following order: Cd > Zn > Cu > Ni > Pb > Cr. PMID:26561822

  19. Simulation of Tritium Transport and Groundwater Age in a Variably Saturated 3D Model, Lake Rotorua Catchment, New Zealand

    Science.gov (United States)

    Daughney, C.; Toews, M. W.; Morgenstern, U.; Cornaton, F. J.; Jackson, B. M.

    2013-12-01

    -squares-based PEST, and manual adjustment of Cauchy boundary conditions to better match observed stream and spring flows. The transport model parameters were calibrated using PEST. Direct age simulations were then performed using the calibrated transport model. This allowed determination of the distribution of water age and lifetime expectancy at each point in the model domain. Results showed that travel time from the land surface through the aquifer system and into Lake Rotorua varies from a few years to more than 200 years, depending on location. Notable from a management perspective is that rainfall recharge to the aquifer system far from the lake can still reach the lake quickly where groundwater emerges into a river that then flows rapidly to the lake.

  20. Reddies River Lake, Yadkin River Basin, Reddies River, North Carolina. General Design Memorandum. Phase I. Plan Formulation.

    Science.gov (United States)

    1975-03-01

    anler-day long’l. of 4.0 hours). • r * ~ * ~ - ~ Tabla 4. Ire.,tc.,ted anuai sport f is, irvest iu Reddies River, Tiliery azd Tucaertowm Reservoirs...tes I )L-partmnt of~ the I ttrior tv r, -n - .. j ,,. r p, f,’’.M NatkmM Pks CwdotuM 167217 XII 9 FEDERAL POWErJ COMMISSION OuOneL OvIe eCa 730

  1. Isotopic evidence for the spatial heterogeneity of the planktonic food webs in the transition zone between river and lake ecosystems.

    Science.gov (United States)

    Doi, Hideyuki; Zuykova, Elena I; Shikano, Shuichi; Kikuchi, Eisuke; Ota, Hiroshi; Yurlova, Natalia I; Yadrenkina, Elena

    2013-01-01

    Resources and organisms in food webs are distributed patchily. The spatial structure of food webs is important and critical to understanding their overall structure. However, there is little available information about the small-scale spatial structure of food webs. We investigated the spatial structure of food webs in a lake ecosystem at the littoral transition zone between an inflowing river and a lake. We measured the carbon isotope ratios of zooplankton and particulate organic matter (POM; predominantly phytoplankton) in the littoral zone of a saline lake. Parallel changes in the δ (13)C values of zooplankton and their respective POMs indicated that there is spatial heterogeneity of the food web in this study area. Lake ecosystems are usually classified at the landscape level as either pelagic or littoral habitats. However, we showed small-scale spatial heterogeneity among planktonic food webs along an environmental gradient. Stable isotope data is useful for detecting spatial heterogeneity of habitats, populations, communities, and ecosystems.

  2. Flood hazards along the Toutle and Cowlitz rivers, Washington, from a hypothetical failure of Castle Lake blockage

    Science.gov (United States)

    Laenen, Antonius; Orzol, L.L.

    1987-01-01

    A recent evaluation of groundwater and material in the blockage impounding Castle Lake shows that the blockage is potentially unstable against failure from piping due to heave and internal erosion when groundwater levels are seasonally high. There is also a remote possibility that a 6.8 or greater magnitude earthquake could occur in the Castle Lake area when groundwater levels are critically high. If this situation occurs, the debris blockage that confines Castle Lake could breach from successive slope failure with liquefaction of a portion of the blockage. A dam-break computer model was used to simulate discharge through a hypothetical breach in the Castle Lake blockage that could be caused by failure by heave, internal erosion, or liquefaction. Approximately 18,500 acre-ft of stored water would be released from an assumed breach that fully developed to a 1,000-ft width over a 15-minute time period. The resulting flood, incorporating 3.4 x 10 to the 6th power cu yd of the debris blockage, would reach a peak magnitude of 1,500,000 cu ft/s (cubic feet per second). The flood is also assumed to incorporate an additional 137x10 to the 6th power cu yd of saturated debris material from downstream deposits. Flow is considered to be hyperconcentrated with sediment throughout the course of the flood. The hypothetical hyperconcentrated flow is routed downstream, superimposed on normal winter flood flows by use of a one-dimensional unsteady-state numerical streamflow simulation model. From a starting magnitude of 1,500,000 cu ft/s, the peak increases to 2,100,000 cu ft/s at N-1 Dam (12 mi downstream) and attenuates to 1,200,000 cu ft/s at Kid Valley (25 mi downstream) , to 100,000 cu ft/s at Longview and the confluence of the Columbia River (65 mi downstream). From time of breach, the flood peak would take 2.2 hr to reach Toutle, 3.8 hr to reach Castle Rock, and 8.5 hr to reach Longview. Communities of Toutle , Castle Rock, Kelso, and Longview would experience extreme to

  3. Modeling Antarctic Subglacial Lake Filling and Drainage Cycles

    Science.gov (United States)

    Dow, Christine F.; Werder, Mauro A.; Nowicki, Sophie; Walker, Ryan T.

    2016-01-01

    The growth and drainage of active subglacial lakes in Antarctica has previously been inferred from analysis of ice surface altimetry data. We use a subglacial hydrology model applied to a synthetic Antarctic ice stream to examine internal controls on the filling and drainage of subglacial lakes. Our model outputs suggest that the highly constricted subglacial environment of our idealized ice stream, combined with relatively high rates of water flow funneled from a large catchment, can combine to create a system exhibiting slow-moving pressure waves. Over a period of years, the accumulation of water in the ice stream onset region results in a buildup of pressure creating temporary channels, which then evacuate the excess water. This increased flux of water beneath the ice stream drives lake growth. As the water body builds up, it steepens the hydraulic gradient out of the overdeepened lake basin and allows greater flux. Eventually this flux is large enough to melt channels that cause the lake to drain. Lake drainage also depends on the internal hydrological development in the wider system and therefore does not directly correspond to a particular water volume or depth. This creates a highly temporally and spatially variable system, which is of interest for assessing the importance of subglacial lakes in ice stream hydrology and dynamics.

  4. Stochastic modelling of river morphodynamics

    NARCIS (Netherlands)

    Van Vuren, B.G.

    2005-01-01

    Modern river management has to reconcile a number of functions, such as protection against floods and provision of safe and efficient navigation, floodplain agriculture, ecology and recreation. Knowledge on uncertainty in fluvial processes is important to make this possible, to design effective rive

  5. Comparative bioenergetics modeling of two Lake Trout morphotypes

    Science.gov (United States)

    Kepler, Megan V.; Wagner, Tyler; Sweka, John A.

    2014-01-01

    Efforts to restore Lake Trout Salvelinus namaycush in the Laurentian Great Lakes have been hampered for decades by several factors, including overfishing and invasive species (e.g., parasitism by Sea Lampreys Petromyzon marinus and reproductive deficiencies associated with consumption of Alewives Alosa pseudoharengus). Restoration efforts are complicated by the presence of multiple body forms (i.e., morphotypes) of Lake Trout that differ in habitat utilization, prey consumption, lipid storage, and spawning preferences. Bioenergetics models constitute one tool that is used to help inform management and restoration decisions; however, bioenergetic differences among morphotypes have not been evaluated. The goal of this research was to investigate bioenergetic differences between two actively stocked morphotypes: lean and humper Lake Trout. We measured consumption and respiration rates across a wide range of temperatures (4–22°C) and size-classes (5–100 g) to develop bioenergetics models for juvenile Lake Trout. Bayesian estimation was used so that uncertainty could be propagated through final growth predictions. Differences between morphotypes were minimal, but when present, the differences were temperature and weight dependent. Basal respiration did not differ between morphotypes at any temperature or size-class. When growth and consumption differed between morphotypes, the differences were not consistent across the size ranges tested. Management scenarios utilizing the temperatures presently found in the Great Lakes (e.g., predicted growth at an average temperature of 11.7°C and 14.4°C during a 30-d period) demonstrated no difference in growth between the two morphotypes. Due to a lack of consistent differences between lean and humper Lake Trout, we developed a model that combined data from both morphotypes. The combined model yielded results similar to those of the morphotype-specific models, suggesting that accounting for morphotype differences may

  6. Modelling cascading and erosional processes for glacial lake outburst floods in the Quillcay catchment, Huaraz, Cordillera Blanca, Peru

    Science.gov (United States)

    Baer, Patrick; Huggel, Christian; Frey, Holger; Chisolm, Rachel; McKinney, Daene; McArdell, Brian; Portocarrero, Cesar; Cochachin, Alejo

    2016-04-01

    Huaraz as the largest city in Cordillera Blanca has faced a major disaster in 1941, when an outburst flood from Lake Palcacocha killed several thousand people and caused widespread destruction. Recent studies on glacial lake outburst flood (GLOF) modelling and early warning systems focussed on Lake Palcacocha which has regrown after the 1941 event, from a volume of half a million m3 in 1974 to a total volume of more than 17 million m3 today. However, little research has been conducted so far concerning the situation of other lakes in the Quillcay catchment, namely Lake Tullparaju (12 mill. m3) and Cuchillacocha (2.5 mill. m3), which both also pose a threat to the city of Huaraz. In this study, we modelled the cascading processes at Lake Tullparaju and Lake Cuchillacocha including rock/ice avalanches, flood wave propagation in the lake and the resulting outburst flood and debris flows. We used the 2D model RAMMS to simulate ice avalanches. Model output was used as input for analytical 2D and 3D calculations of impact waves in the lakes that allowed us to estimate dam overtopping wave height. Since the dimension of the hanging glaciers above all three lakes is comparable, the scenarios in this study have been defined similar to the previous study at Lake Palcacocha. The flow propagation model included sediment entrainment in the steeper parts of the catchment, adding up to 50% to the initial flow volume. The results for total travel time as well as for inundated areas and flow depth and velocity in the city of Huaraz are comparable to the previous studies at Lake Palcacocha. This underlines the importance of considering also these lakes within an integral hazard analysis for the city of Huaraz. A main challenge for modelling GLOFs in the Quillcay catchment using RAMMS is the long runout distance of over 22 km combined with the very low slope gradient of the river. Further studies could improve the process understanding and could focus on more detailed investigations

  7. Heavy metals pollution status in surface sediments (rivers and artifical lakes, Serbia)

    Science.gov (United States)

    Sakan, Sanja; Đorđević, Dragana

    2017-04-01

    Potentially hazardous trace elements, often in literature referred as "heavy metals", are deemed serious pollutants due to their toxicity, persistence and non-degradability in the environment. These elements play an important role in extent of water pollution and threaten the health of populations and ecosystems. As the sink of heavy metals, sediment beds adsorb metals in quantities that are many times higher than those found in the water column in the long-term polluted water environment. It is believed that most of the metal content, as much as 90% in aquatic sediments is bound to sediments. Metal contamination in these sediments could be directly affect the river water quality, resulting in potential consequences to the sensitive lowest levels of the food chain and ultimately to human health. The objective of this research was the evaluation of heavy metal contamination level in sediments of the most important rivers and artificial lakes in Serbia. The heavy metal enrichment in studied sediments was conducted by using: determination of total metal content, sequential extraction procedure for the fractionation of studied elements, quantification of the metal enrichment degree in the sediments by calculating geo-accumulation indices, determination of actual and potential element availability and application of BRAI index for the assessment of heavy metal bioavailability. The sediments were found to be contaminated by heavy metals to various extents, mostly with Cd, Cu, and Zn. The significant variation in heavy metal distribution among samples collected in this large region, encompassing all Serbian watersheds, suggests the selective contamination of sediments by heavy metals. Elevated concentrations of elements in most cases were detected in samples of river sediments, since artificial lake reservoirs are usually built in rural areas, where the less anthropogenic pollution. Rivers often flow through the towns and these water basins less or more loaded

  8. Summary of investigations on chemical compounds found in fish tissue taken from Wasilla Lake in the Matanuska Valley and Delta Clearwater River and Lake in the Tanana Valley, 1977

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is a summary of investigations on chemical compounds found in fish tissue take from Wasilla Lake in the Matansuka Valley and Delta Clearwater River and...

  9. Simulating Water and Nutrient Transport in an Urbanizing Agricultural Watershed with Lake-Level Regulation Using a Coupled Modeling Approach

    Science.gov (United States)

    Chen, X.; Motew, M.; Booth, E.; Carpenter, S. R.; Steven, L. I.; Kucharik, C. J.

    2015-12-01

    The Yahara River basin located in southern Wisconsin is a watershed with long-term eutrophication issues due largely to a thriving dairy industry upstream of the Madison chain of lakes. Steady phosphorus loading from manure production and other sources has contributed directly to blue-green algae blooms and poor water quality in the lakes and river system, and is often viewed as the most important environmental problem to solve in the region. In this study, the daily streamflow and monthly nitrogen (N), sediment and phosphorus (P) transport, as well as the lake levels in the Yahara River basin are simulated using a physically-based hydrologic routing model: the Terrestrial Hydrology Model with Biogeochemistry (THMB). The original model includes representation of water and nitrogen transport but as part of this work, P transport and lake regulation are added into the model. The modified THMB model is coupled with the AgroIBIS-VSF agroecosystem model to represent dynamic coupling between agricultural management in the watershed, and N, P, and sediment transport to lakes and streams. We will present model calibration and validation results that demonstrate the hydrologic routing capability of THMB for a spatial resolution of 220m, several orders of magnitude finer than attempted previously with THMB. The calibrated modeling system is being used to simulate the impacts of climate change and land management on biogeochemistry in the Yahara watershed under four different pathways of change to the year 2070 (Yahara 2070). These scenarios are Abandonment and Renewal, Accelerated Innovation, Connected Communities and Nested Watersheds, which are used to better understand how future decision-making influences the provisioning and trade-offs of ecosystem services.

  10. Origin of the Turkwel delta trajectory (Lake Turkana, Kenya): insights from numerical modeling (DIONISOS)

    Science.gov (United States)

    Alexis, Nutz; Pierre, Dietrich; Vafe, Soumahoro; Mathieu, Schuster; Jean-François, Ghienne

    2016-04-01

    Deltas simultaneously respond to modifications in parameters such as water discharge, sediment supply and base-level change. Those parameters are driven by a number of potential external forcing processes, nevertheless mainly corresponding to tectonism and climate. In this study, geomorphology and numerical modeling are coupled in order to provide analysis of the delta complex of the Turkwel River (Lake Turkana, Kenya). The Turkwel delta complex is 35 km long, forming one of the major deltaic systems that has fringed Lake Turkana during the Holocene. It developed during the lake level regression at the end of the holocene African Humid Period and correspond to a typical forced-regressive delta. Trajectory analysis was performed on three transects cross-cutting the deltaic complex. Transects consistently display five slightly descending (slope gradient: >0° to 0.4°) plateaus separated by four abrupt steps of higher slope gradients (1° to 3.8°). Conventional interpretations presume that the deltaic trajectory results from either (1) four abrupt accelerations in lake level fall during the continuous regression, (2) four abrupt declines in sediment supply and/or water discharge during a steady lake level fall or (3) a combination of both. We used numerical stratigraphic modeling (Dionisos) in order to test the aforementioned hypotheses as the origin of observed trajectories. We concluded that causal relationships between sediment supply, lake level change and progradation trajectory are not as straightforward as recurrently envisioned. We think that this contribution brings new lights on the relationships between deltaic architectures and controlling factors.

  11. Subaqueous geology and a filling model for Crater Lake, Oregon

    Science.gov (United States)

    Nathenson, M.; Bacon, C.R.; Ramsey, D.W.

    2007-01-01

    Results of a detailed bathymetric survey of Crater Lake conducted in 2000, combined with previous results of submersible and dredge sampling, form the basis for a geologic map of the lake floor and a model for the filling of Crater Lake with water. The most prominent landforms beneath the surface of Crater Lake are andesite volcanoes that were active as the lake was filling with water, following caldera collapse during the climactic eruption of Mount Mazama 7700 cal. yr B.P. The Wizard Island volcano is the largest and probably was active longest, ceasing eruptions when the lake was 80 m lower than present. East of Wizard Island is the central platform volcano and related lava flow fields on the caldera floor. Merriam Cone is a symmetrical andesitic volcano that apparently was constructed subaqueously during the same period as the Wizard Island and central platform volcanoes. The youngest postcaldera volcanic feature is a small rhyodacite dome on the east flank of the Wizard Island edifice that dates from 4800 cal. yr B.P. The bathymetry also yields information on bedrock outcrops and talus/debris slopes of the caldera walls. Gravity flows transport sediment from wall sources to the deep basins of the lake. Several debris-avalanche deposits, containing blocks up to 280 m long, are present on the caldera floor and occur below major embayments in the caldera walls. Geothermal phenomena on the lake floor are bacterial mats, pools of solute-rich warm water, and fossil subaqueous hot spring deposits. Lake level is maintained by a balance between precipitation and inflow versus evaporation and leakage. High-resolution bathymetry reveals a series of up to nine drowned beaches in the upper 30 m of the lake that we propose reflect stillstands subsequent to filling of Crater Lake. A prominent wave-cut platform between 4 m depth and present lake level that commonly is up to 40 m wide suggests that the surface of Crater Lake has been at this elevation for a very long time

  12. Assessing trends in organochlorine concentrations in Lake Winnipeg fish following the 1997 red river flood

    Science.gov (United States)

    Stewart, A.R.; Stern, G.A.; Lockhart, W.L.; Kidd, K.A.; Salki, A.G.; Stainton, M.P.; Koczanski, K.; Rosenberg, G.B.; Savoie, D.A.; Billeck, B.N.; Wilkinson, Philip M.; Muir, D.C.G.

    2003-01-01

    As we move toward the virtual elimination of persistent organic pollutants (POPs) in the environment our understanding of how short-term variability affects long-term trends of POPs in natural populations will become increasingly more important. In this study we report short-term trends in organochlorine (OC) levels in fish from Lake Winnipeg in the months and years following the 1997 100-year flood of the Red River ecosystem. Our goal was to understand the effects of an episodic event on OC levels in benthic and pelagic invertebrates and in fish. Despite elevated loading of OCs into the south basin of Lake Winnipeg during the flood there were no differences in OC levels of surface sediments or emergent mayflies. After adjusting for differences in lipid content and length among sample times, we did find significant increases in total DDT (??DDT) and total polychlorinated biphenyl (??PCB) post-flood (March 1999) in top predators including walleye and burbot. Significant increases were also observed in OC concentrations of zooplankton and yellow perch (> 2 fold in ??PCB, ??DDT, total chlordane (??CHL), total chlorobenzenes (??CBZ)) and walleye (1.4 fold ??PCB) over a 2-month period in the summer following the flood. Analysis of specific congener patterns over time suggest that the major changes in fish OC levels pre- and post-flood did not appear to be linked to transport of new compounds into the Lake during the flood, but to species shifts within the plankton community. Our results indicate that short-term variation (???2 months) in OC distributions within biota may be equal to or greater than those resulting from episodic events such as spring floods.

  13. Preliminary juvenile Lost River and shortnose sucker investigations in Clear Lake, California--2011 pilot study summary

    Science.gov (United States)

    Burdick, Summer M.; Rasmussen, Josh

    2012-01-01

    Poor recruitment appears to limit the recovery of Lost River and shortnose sucker populations in Clear Lake Reservoir, California, but the cause is unknown. Adult suckers migrate up Willow Creek and its tributaries to spawn in some years, but low flow in Willow Creek may inhibit spawning migrations in other years. It is unclear whether spawning is successful, larvae survive, or juveniles persist to adulthood. Environmental variables associated with successful spawning or young-of-year survival have not been identified and early life history for these populations is poorly understood. The U.S. Geological Survey in cooperation with the U.S. Fish and Wildlife Service and Ruby Pipeline L.L.C. Corporation (El Paso, Tex.) initiated a study in 2011 to better understand juvenile sucker life history in Clear Lake Reservoir, and to identify constraints in the early life history that may limit recruitment to the adult spawning populations. This is a report on the 2011 pilot study for this project.

  14. Heavy metal pollution of lakes along the mid-lower reaches of the Yangtze River in China: intensity, sources and spatial patterns.

    Science.gov (United States)

    Zeng, Haiao; Wu, Jinglu

    2013-02-26

    Lakes in the middle and lower reaches of the Yangtze River form a shallow lake group unique in the World that is becoming increasingly polluted by heavy metals. Previous studies have largely focused on individual lakes, with limited exploration of the regional pattern of heavy metal pollution of the lake group in this area. This paper explores the sources, intensity and spatial patterns of heavy metal pollution of lake sediments. A total of 45 sample lakes were selected and the concentrations of key metal elements in the sediments of each lake were measured. The cluster analysis (CA), principal component analysis (PCA) and Geo-accumulation index (I(g)) analysis permitted analysis of the source and pollution intensity of the target lakes. Results suggested a notable spatial variation amongst the sample lakes. Lakes in the upper part of the lower reach of the Yangtze River surrounded by typical urban landscapes were strongly or extremely polluted, with high concentrations of Pb, Zn, Cu and Cd in their sediments. This was attributed to large amount of untreated industrial discharges and municipal sewage produced within the lake catchments. In contrast, the heavy-metal pollution of lakes in the Taihu Delta area was notably lower due to industrial restructuring and implementation of effective environmental protection measures. Lakes along the middle reach of Yangtze River surrounded by agricultural areas were unpolluted to moderately polluted by heavy metals overall. Our results suggested that lakes in the central part of China require immediate attention and efforts should be made to implement management plans to prevent further degradation of water quality in these lakes.

  15. Development of Multivariate Regression Model for the Hydrologic System of Chari-Logone Catchment of the Lake Chad Basin.

    Science.gov (United States)

    Djimadoumngar, K. N.; Lee, J.; Bila, M. D.; Djoret, D.; Ichoku, C. M.

    2016-12-01

    Food security and water shortage from frequent droughts have been major issues in the northern sub-Saharan Africa (NSSA). The shrinking Lake Chad is one of the examples experiencing severe droughts and insecure food production. One of major challenges in the NSSA is the lack of data collection and monitoring systems to support a decision-making process in the agriculture and water resources management. The present study aims to help better understand a hydrologic system of the Lake Chad using multivariate regression models and enhance the models to forecast the river discharge along the Chari-Logone river system, which contributes over 90% of water into the Lake. As regressands, the river discharge data from two monitoring stations at Bongor and Logone-Gana were collected from 2001-2007. The regressors include precipitation, soil moisture, soil and air temperature, specific humidity, evapotranspiration and surface runoff. The Tropical Rainfall Measuring Mission (TRMM) data were used for the precipitation, and all other regressor parameters were obtained from the Global Land Data Assimilation System (GLDAS). We performed cross-correlation analysis between the river discharge and each regressor parameter to quantify the time lag to have the best correlation, which implies the responding time of the river discharge to the change of other hydrological parameters. The estimated time lags were integrated into the multivariate regression model. The results show that, for the river discharge data, precipitation, soil moisture, and surface runoff have linear relationships while evapotranspiration, soil and air temperature, and specific humidity have non-linear relationships. The observed river discharge and the predicted one, which is a function of precipitation and soil moisture, shows a good match with 93% of correlation.

  16. Forecasting effects of climate change on Great Lakes fisheries: models that link habitat supply to population dynamics can help

    Science.gov (United States)

    Jones, Michael L.; Shuter, Brian J.; Zhao, Yingming; Stockwell, Jason D.

    2006-01-01

    Future changes to climate in the Great Lakes may have important consequences for fisheries. Evidence suggests that Great Lakes air and water temperatures have risen and the duration of ice cover has lessened during the past century. Global circulation models (GCMs) suggest future warming and increases in precipitation in the region. We present new evidence that water temperatures have risen in Lake Erie, particularly during summer and winter in the period 1965–2000. GCM forecasts coupled with physical models suggest lower annual runoff, less ice cover, and lower lake levels in the future, but the certainty of these forecasts is low. Assessment of the likely effects of climate change on fish stocks will require an integrative approach that considers several components of habitat rather than water temperature alone. We recommend using mechanistic models that couple habitat conditions to population demographics to explore integrated effects of climate-caused habitat change and illustrate this approach with a model for Lake Erie walleye (Sander vitreum). We show that the combined effect on walleye populations of plausible changes in temperature, river hydrology, lake levels, and light penetration can be quite different from that which would be expected based on consideration of only a single factor.

  17. Levels, fluxes and time trends of persistent organic pollutants in Lake Thun, Switzerland: Combining trace analysis and multimedia modeling

    Energy Technology Data Exchange (ETDEWEB)

    Bogdal, Christian [Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zuerich (Switzerland); Empa, Swiss Federal Laboratories for Materials Testing and Research, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Scheringer, Martin, E-mail: scheringer@chem.ethz.ch [Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zuerich (Switzerland); Schmid, Peter [Empa, Swiss Federal Laboratories for Materials Testing and Research, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Blaeuenstein, Markus [Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zuerich (Switzerland); Kohler, Martin [State Food Law Enforcement Authority, Werkhofstrasse 5, CH-4509 Solothurn (Switzerland); Hungerbuehler, Konrad [Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zuerich (Switzerland)

    2010-08-01

    Levels, mass fluxes, and time trends of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in Lake Thun, a peri-Alpine lake, are investigated. We present measurements of PBDEs and PCBs in air, lake water, lake sediment, and tributary water. These measurements are combined with a multimedia fate model, based on site-specific environmental parameters from the lake catchment. Measured loadings of PBDEs and PCBs in air and tributaries were used to drive the model. The model satisfactorily reproduces PBDE and PCB congener patterns in water and sediment, but it tends to yield concentrations in water below the measurements and concentrations in sediment exceeding the measurements. A sensitivity analysis reveals that partitioning of PBDEs and PCBs between the aqueous dissolved phase and suspended particulate matter in the water column strongly affects the model results, in particular the concentrations in water and sediment. For lower-brominated PBDEs, approximately 70% and 30% of input into the lake stems from atmospheric deposition and from tributaries, respectively. For heavier PBDEs and all PCBs, rivers appear to deliver the major load (64-92%). Waste water effluents are of minor importance. 50-90% of the total input is buried in the permanent sediment. Sediment burial makes PBDEs and PCBs less available for recycling in the environment, and reduces concentrations in the outflowing river. If use of deca-BDE increases in the future, levels in Lake Thun will follow the same trend. If the use and resulting environmental emissions decrease, concentrations in water will rapidly decline, according to our calculations, while sediment levels will decrease at a considerably slower rate.

  18. Water-Energy-Food Nexus in a Transboundary River Basin: The Case of Tonle Sap Lake, Mekong River Basin

    Directory of Open Access Journals (Sweden)

    Marko Keskinen

    2015-10-01

    Full Text Available The water-energy-food nexus is promoted as a new approach for research and policy-making. But what does the nexus mean in practice and what kinds of benefits does it bring? In this article we share our experiences with using a nexus approach in Cambodia’s Tonle Sap Lake area. We conclude that water, energy and food security are very closely linked, both in the Tonle Sap and in the transboundary Mekong River Basin generally. The current drive for large-scale hydropower threatens water and food security at both local and national scales. Hence, the nexus provides a relevant starting point for promoting sustainable development in the Mekong. We also identify and discuss two parallel dimensions for the nexus, with one focusing on research and analysis and the other on integrated planning and cross-sectoral collaboration. In our study, the nexus approach was particularly useful in facilitating collaboration and stakeholder engagement. This was because the nexus approach clearly defines the main themes included in the process, and at the same time widens the discussion from mere water resource management into the broader aspects of water, energy and food security.

  19. Lake on life support: Evaluating urban lake management measures by using a coupled 1D-modelling approach

    Science.gov (United States)

    Ladwig, Robert; Kirillin, Georgiy; Hinkelmann, Reinhard; Hupfer, Michael

    2017-04-01

    Urban surface water systems and especially lakes are heavily stressed and modified systems to comply with water management goals and expectations. In this study we focus on Lake Tegel in Berlin, Germany, as a representative of heavily modified urban lakes. In the 20th century, Lake Tegel received increased loadings of nutrients and leached heavy metals from an upstream sewage farm resulting in severe eutrophication problems. The construction of two upstream treatment plants caused a lowering of nutrient concentrations and a re-oligotrophication of the lake. Additionally, artificial aerators, to keep the hypolimnion oxic, and a lake pipeline, to bypass water for maintaining a minimum discharge, went into operation. Lake Tegel is still heavily used for drinking water extraction by bank filtration. These interacting management measures make the system vulnerable to changing climate conditions and pollutant loads. Past modelling studies have shown the complex hydrodynamics of the lake. Here, we are following a simplified approach by using a less computational time consuming vertical 1D-model to simulate the hydrodynamics and the ecological interactions of the system by coupling the General Lake Model to the Aquatic Ecodynamics Model Library 2. For calibration of the multidimensional parameter space we applied the Covariance Matrix Adaption-Evolution Strategy algorithm. The model is able to sufficiently replicate the vertical field temperature profiles of Lake Tegel as well as to simulate similar concentration ranges of phosphate, dissolved oxygen and nitrate. The calibrated model is used to run an uncertainty analysis by sampling the simulated data within the meaning of the Metropolis-Hastings algorithm. Finally, we are evaluating different scenarios: (1) changing air temperatures, precipitation and wind speed due to effects of climate change, (2) decreased discharges into the lake due to bypassing treated effluents into a near stream instead of Lake Tegel, and (3

  20. [Distribution and Potential Ecological Risk Assessment of Heavy Metals in Surface Sediments of Inflow Rivers to Northeastern Lake Tanganyika].

    Science.gov (United States)

    Yu, Cheng; Chen, Shuang; Zhang, Lu

    2016-02-15

    As the second deepest lake in Africa, Lake Tanganyika plays an important role in supplying fish protein for citizens in the catchment. However, the lake is increasingly threatened by environmental pollution with the development of social economy and expanding of population. In order to reveal the external source of heavy metals in Lake Tanganyika, 16 surface sediment samples from the rivers which flow into the northeast of the lake were collected and analyzed. Besides the contents, the potential ecological risk indices (RI) of each heavy metal were also analyzed. Furthermore, the relationship, between land use and the spatial distribution of heavy metals was also discussed. The average contents of Cu, Zn, Cd, Pb and Hg were 18. 4, 21.2, 0.05, 6.6 mg x kg(-1) and 8.4 ng x g(-1), respectively, with the maximum values of Zn, Pb and Cd located in Bujumbura urban rivers. The data indicated that all the inflow rivers were at low potential ecological risk. RI of heavy metals ranked as the following order: Cd > Hg > Cu > Pb > Zn, as Cd being the key element contributing to the risk. The relationship between land use and heavy metals showed that the contents of heavy metals were highest in urban areas, followed by estuarine wetlands, and woodlands were least polluted by heavy metals. This distribution type implied that human activities could cause the heavy metal accumulation in the surface sediments of nearby rivers. The urban areas and estuarine wetlands need to be concerned in the further study.

  1. Modeling lakes and reservoirs in the climate system

    Science.gov (United States)

    MacKay, M.D.; Neale, P.J.; Arp, C.D.; De Senerpont Domis, L. N.; Fang, X.; Gal, G.; Jo, K.D.; Kirillin, G.; Lenters, J.D.; Litchman, E.; MacIntyre, S.; Marsh, P.; Melack, J.; Mooij, W.M.; Peeters, F.; Quesada, A.; Schladow, S.G.; Schmid, M.; Spence, C.; Stokes, S.L.

    2009-01-01

    Modeling studies examining the effect of lakes on regional and global climate, as well as studies on the influence of climate variability and change on aquatic ecosystems, are surveyed. Fully coupled atmosphere-land surface-lake climate models that could be used for both of these types of study simultaneously do not presently exist, though there are many applications that would benefit from such models. It is argued here that current understanding of physical and biogeochemical processes in freshwater systems is sufficient to begin to construct such models, and a path forward is proposed. The largest impediment to fully representing lakes in the climate system lies in the handling of lakes that are too small to be explicitly resolved by the climate model, and that make up the majority of the lake-covered area at the resolutions currently used by global and regional climate models. Ongoing development within the hydrological sciences community and continual improvements in model resolution should help ameliorate this issue.

  2. Reconstruction and modelling of the 1977 Glacial Lake Outburst Flood (GLOF) of the Engaño Lake, Chilean Patagonia.

    Science.gov (United States)

    Iribarren Anacona, Pablo; Norton, Kevin; Mackintosh, Andrew

    2015-04-01

    Floods from moraine-dammed lake failures can result in severe damage to mountain communities. GLOFs can also cause long-standing effects in riverine landscapes, due to the high intensity (i.e. great depth and high velocities) and long reach capacity of these events. GLOFs may increase in frequency as glaciers retreat and new lakes develop, highlighting the need for a better understanding of GLOF dynamics and the measures to reduce their negative outcomes. In Patagonia at least 16 moraine-dammed lakes have failed in historic time, however, data about GLOF dynamics and impacts are limited since GLOFs have mainly affected uninhabited areas and ungauged rivers. In March 1977, however, a GLOF flooded a small village (~130 inhabitants) in Chilean Patagonia. We reconstruct the dynamics of this event by semi-structured interviews, interpretation of satellite images (Landsat MSS) and two dimensional (2D) hydraulic modelling (using HEC-RAS 5.0 BETA and the SRTM v4 DEM). This reconstruction provides insights into GLOF behaviour, as well as the planning issues that led to socioeconomic consequences, which included relocation of the village. We mapped the flood extent and compiled data of flood depth and timing to constrain the 2D GLOF simulations. Modelling shows that the water released by the GLOF was in the order of 12-13 million cubic metres and that the flood reached Bahía Murta Viejo, located ~26 km from the failed lake, 2-3 hours after the moraine dam was breached. The flood lasted for about ten hours (at the village), although the peak discharge occurred after only one hour at this site. The maximum water depth at Bahía Murta Viejo was 1.5 m, however, water depths of up to 20 metres were simulated in upstream constricted reaches. The overall flood dynamics suggested by interviews and geomorphic mapping, including hydraulic ponding upstream of bedrock gorges, was well represented in the 2D simulations in spite of the coarse resolution (~80 m) of the DEM used. The

  3. 长江中下游地区湖泊资源可持续利用%The Sustainable Utilization of Lake Resources in the Middle and Lower Reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on geographical and hydrological characteristics of lakes in the middle and lower reaches of Yangtze River, this paper analyzes the factors rest ricting the sustainable utilization of lake resources, including the conflict am ong agriculture water conservancy, and fishery, lake water pollution and eutroph ication, lake siltation and swamping. The countermeasures and suggestions, such a s improving the strategic status of lake harnessing, strengthening integrated ma nagement of lakes and their watershed, strengthening researches on lake environm ent and lake resources, are proposed to practice the sustainable utilization of lake resources.

  4. An Evaluation of Ecosystem Restoration and Management Options for the Calhoun and Gilbert Lake Divisions of Two Rivers National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — An overview of past and current conditions of the Calhoun and Gilbert Lake Divisions of the Two Rivers National Wildlife Refuge and an evaluation of proposed...

  5. Upper Klamath Lake Basin nutrient-loading study; assessment of historic flows in the Williamson and Sprague rivers

    Science.gov (United States)

    Risley, John C.; Laenen, Antonius

    1999-01-01

    The Williamson River Basin, located in southcentral Oregon, has a drainage area of approximately 3,000 square miles. The Sprague River, which flows into the Williamson River Basin, has a drainage area of 1,580 square miles. Together, the Williamson and Sprague Rivers supply about one-half of the inflow to Upper Klamath Lake. Various statistical techniques, which included trend tests, double-mass curves, and two-sample tests, were used to detect significant changes in the precipitation-runoff relation for the Williamson and Sprague River Basins. Flows from these two rivers were compared with the precipitation and air temperature records collected at Klamath Falls to assess the effect of climate on flow variations. Most of the double-mass curves showed a major break in the slope of the curve occurring around 1950 and a smaller one near 1990. For the years 1930?50 and 1990?96, February through May flows were relatively lower in the Williamson River than in rivers in nearby basins, by an average of 25,000 acre-feet per year and 36,000 acre-feet per year, respectively, for the 4-month period. From 1950 through 1963, flows were generally higher in the Williamson River compared with the nearby rivers by an average of 38,000 acre-feet for the 4 months. In July through September of 1945?51, 1970?76, and 1992?96, flows were lower in the Williamson River than in the comparison rivers by an average of about 6,000 acre-feet for the 3-month period. Two-sample statistical tests of the annual flow data sets for the Williamson and Sprague Rivers showed a significant increase in the estimated population mean for the period 1951?96 compared to the estimated population mean for the period 1922?50. However, climate data, which included annual precipitation data from Klamath Falls, Crater Lake, and Medford, and annual air temperature data from Klamath Falls, all showed no significant difference between the two periods. During the past century, various human land-use activities, such as

  6. Numerical modeling of vertical stratification of Lake Shira in summer

    NARCIS (Netherlands)

    Belolipetsky, P.; Belolipetsky, V.M.; Genova, S.N.; Mooij, W.M.

    2010-01-01

    A one-dimensional numerical model and a two-dimensional numerical model of the hydrodynamic and thermal structure of Lake Shira during summer have been developed, with several original physical and numerical features. These models are well suited to simulate the formation and dynamics of vertical st

  7. 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

  8. Reconstructing late Pliocene to middle Pleistocene Death Valley lakes and river systems as a test of pupfish (Cyprinodontidae) dispersal hypotheses

    Science.gov (United States)

    Knott, J.R.; Machette, M.N.; Klinger, R.E.; Sarna-Wojcicki, A. M.; Liddicoat, J.C.; Tinsley, J. C.; David, B.T.; Ebbs, V.M.

    2008-01-01

    During glacial (pluvial) climatic periods, Death Valley is hypothesized to have episodically been the terminus for the Amargosa, Owens, and Mojave Rivers. Geological and biological studies have tended to support this hypothesis and a hydrological link that included the Colorado River, allowing dispersal of pupfish throughout southeastern California and western Nevada. Recent mitochondrial deoxyribonucleic acid (mtDNA) studies show a common pupfish (Cyprinodontidae) ancestry in this region with divergence beginning 3-2 Ma. We present tephrochronologic and paleomagnetic data in the context of testing the paleohydrologic connections with respect to the common collection point of the Amargosa, Owens, and Mojave Rivers in Death during successive time periods: (1) the late Pliocene to early Pleistocene (3-2 Ma), (2) early to middle Pleistocene (1.2-0.5 Ma), and (3) middle to late Pleistocene (<0.70.03 Ma; paleolakes Manly and Mojave). Using the 3.35 Ma Zabriskie Wash tuff and 3.28 Ma Nomlaki Tuff Member of the Tuscan and Tehama Formations, which are prominent marker beds in the region, we conclude that at 3-2 Ma, a narrow lake occupied the ancient Furnace Creek Basin and that Death Valley was not hydrologically connected with the Amargosa or Mojave Rivers. A paucity of data for Panamint Valley does not allow us to evaluate an Owens River connection to Death Valley ca. 3-2 Ma. Studies by others have shown that Death Valley was not hydrologically linked to the Amargosa, Owens, or Mojave Rivers from 1.2 to 0.5 Ma. We found no evidence that Lake Manly flooded back up the Mojave River to pluvial Lake Mojave between 0.18 and 0.12 Ma, although surface water flowed from the Amargosa and Owens Rivers to Death Valley at this time. There is also no evidence for a connection of the Owens, Amargosa, or Mojave Rivers to the Colorado River in the last 3-2 m.y. Therefore, the hypothesis that pupfish dispersed or were isolated in basins throughout southeastern California and western

  9. Development and evaluation of a reservoir model for the Chain of Lakes in Illinois

    Science.gov (United States)

    Domanski, Marian M.

    2017-01-27

    Forecasts of flows entering and leaving the Chain of Lakes reservoir on the Fox River in northeastern Illinois are critical information to water-resource managers who determine the optimal operation of the dam at McHenry, Illinois, to help minimize damages to property and loss of life because of flooding on the Fox River. In 2014, the U.S. Geological Survey; the Illinois Department of Natural Resources, Office of Water Resources; and National Weather Service, North Central River Forecast Center began a cooperative study to develop a system to enable engineers and planners to simulate and communicate flows and to prepare proactively for precipitation events in near real time in the upper Fox River watershed. The purpose of this report is to document the development and evaluation of the Chain of Lakes reservoir model developed in this study.The reservoir model for the Chain of Lakes was developed using the Hydrologic Engineering Center–Reservoir System Simulation program. Because of the complex relation between the dam headwater and reservoir pool elevations, the reservoir model uses a linear regression model that relates dam headwater elevation to reservoir pool elevation. The linear regression model was developed using 17 U.S. Geological Survey streamflow measurements, along with the gage height in the reservoir pool and the gage height at the dam headwater. The Nash-Sutcliffe model efficiency coefficients for all three linear regression model variables ranged from 0.90 to 0.98.The reservoir model performance was evaluated by graphically comparing simulated and observed reservoir pool elevation time series during nine periods of high pool elevation. In addition, the peak elevations during these time periods were graphically compared to the closest-in-time observed pool elevation peak. The mean difference in the simulated and observed peak elevations was -0.03 feet, with a standard deviation of 0.19 feet. The Nash-Sutcliffe coefficient for peak prediction was

  10. Mercury contamination in the vicinity of a derelict chlor-alkali plant. Part I: sediment and water contamination of Lake Balkyldak and the River Irtysh.

    Science.gov (United States)

    Ullrich, Susanne M; Ilyushchenko, Mikhail A; Kamberov, Irken M; Tanton, Trevor W

    2007-08-01

    A mercury-cell chlor-alkali plant operated in Pavlodar, Northern Kazakhstan, for 18 years and caused widespread contamination of the surrounding environment. Untreated wastewater from the plant was discharged to Lake Balkyldak, a shallow impounded lake without an outlet. The nearby River Irtysh was also suspected to be impacted by mercury (Hg) via the transport of contaminated groundwater. We took sediment and water samples from both aquatic systems, and also sampled soils along the shoreline of the lake and in the Irtysh flood plain. Sediments from Lake Balkyldak were found to be very heavily contaminated, with Hg concentrations in the surface layer reaching up to approximately 1500 mg kg(-1) near the wastewater outfall pipe. The contaminated lake sediments are prone to wind-driven resuspension and are acting as a strong source of Hg to the water column. Unfiltered lake water samples taken in shallow areas within 10-15 m from the shoreline contained from 0.11 microg Hg L(-1) in the less contaminated northern part of the lake to 1.39 microg L(-1) near the pollutant outfall in the south (up to 7.3 microg L(-1) on windy days). Sediments from the River Irtysh were only slightly impacted, with maximum Hg concentrations of 0.046 mg kg(-1) in the old river channel and 0.36 mg kg(-1) in floodplain oxbow lakes. In water samples from the River Irtysh, Hg was generally not detected, although trace concentrations (3 to 9 ng L(-1)) were found in some samples taken from oxbow lakes. We conclude that the river is not significantly impacted by Hg, but the highly contaminated Lake Balkyldak poses a threat and is in need of remediation. Potential remediation options for the lake are reviewed and are discussed in the context of experiences made at other Hg-contaminated sites.

  11. A fugacity model for source determination of the Lake Baikal region pollution with polychlorinated Biphenyls

    Energy Technology Data Exchange (ETDEWEB)

    Sofiev, M. [Finnish Meteorological Inst., Helsinki (Finland); Galperin, M.; Maslyaev, A. [Inst. of Program Systems, Pereslavl-Zalesskiy (Russian Federation); McLachlan, M. [Stockholm Univ. (Sweden); Wania, F. [Toronto Univ. (Canada)

    2004-09-15

    PCBs were discovered in the Lake Baikal ecosystem by Malakhov et al. and Bobovnikova et al. A follow up to the initial study showed no decrease over 1981-1989 4, in contrast to what has been observed in other water bodies in the industrialised world. Further studies also showed the contamination in pinnipeds to be among the highest measured anywhere. Above studies and other data suggested a presence of a strong local PCB source (or several ones), which has had a widespread adverse effect for the whole region. To locate the source, Mamontov et al. collected samples from 34 sites over the region, the analysis of which showed a gradient of a factor of 1000, with the lowest concentrations at the north-east of Lake Baikal and the highest concentrations close to the city of Usolye Sibirskoye, a centre of the chemical industry in the Angara River valley. A continuous decrease in the soil contamination was observed along the path from Usolye Sibirskoye up the Angara River valley to Lake Baikal and from there north-eastward along the lake. These results indicate that there was (and perhaps still is) a major source of PCBs in the Usolye area, from where the PCBs are dispersed over the region. However, various obstacles prevent direct observations of potential sources. Therefore, a mathematical modelling approach was adopted in a currently ongoing INTAS project aiming to shed some more light on this problem. The model principles, setup and the results of the first experiments are presented in the current paper.

  12. Statistical validation of GCM-simulated climates for the U.S. Great Lakes and the C.I.S. Emba and Ural River basins

    Science.gov (United States)

    Privalsky, V.; Croley, T. E.

    1992-03-01

    Many researchers use outputs from large-scale global circulation models of the atmosphere to assess hydrological and other impacts associated with climate change. However, these models cannot capture all climate variations since the physical processes are imperfectly understood and are poorly represented at smaller regional scales. This paper statistically compares model outputs from the global circulation model of the Geophysical Fluid Dynamics Laboratory to historical data for the United States' Laurentian Great Lakes and for the Emba and Ural River basins in the Commonwealth of Independent States (C.I.S.). We use maximum entropy spectral analysis to compare model and data time series, allowing us to both assess statistical predictabilities and to describe the time series in both time and frequency domains. This comparison initiates assessments of the model's representation of the real world and suggests areas of model improvement.

  13. Tracing the Nitrate Sources of the Yili River in the Taihu Lake Watershed: A Dual Isotope Approach

    Directory of Open Access Journals (Sweden)

    Haiao Zeng

    2014-12-01

    Full Text Available As the third largest freshwater lake in China, Taihu Lake has experienced severe cyanobacterial blooms and associated water quality degradation in recent decades, threatening the human health and sustainable development of cities in the watershed. The Yili River is a main river of Taihu Lake, contributing about 30% of the total nitrogen load entering the lake. Tracing the nitrate sources of Yili River can inform the origin of eutrophication in Taihu Lake and provide hints for effective control measures. This paper explored the nitrate sources and cycling of the Yili River based on dual nitrogen (δ15N and oxygen (δ18O isotopic compositions. Water samples collected during both the wet and dry seasons from different parts of the Yili River permitted the analysis of the seasonal and spatial variations of nitrate concentrations and sources. Results indicated that the wet season has higher nitrate concentrations than the dry season despite the stronger dilution effects, suggesting a greater potential of cyanobacterial blooms in summer. The δ15N-NO3− values were in the range of 4.0‰–14.0‰ in the wet season and 4.8‰–16.9‰ in dry, while the equivalent values of δ18O were 0.5‰–17.8‰ and 3.5‰–15.6‰, respectively. The distribution of δ15N-NO3− and δ18O-NO3− indicated that sewage and manure as well as fertilizer and soil organic matter were the major nitrate sources of the Yili River. Atmospheric deposition was an important nitrate source in the upper part of Yili River but less so in the middle and lower reaches due to increasing anthropogenic contamination. Moreover, there was a positive relationship between δ18O-NO3− and δ15N-NO3− in the wet season, indicating a certain extent of denitrification. In contrast, the δ18O-δ15N relationship in the dry season was significantly negative, suggesting that the δ15N and δ18O values were determined by a mixing of different nitrate sources.

  14. Communities of gastrointestinal helminths of fish in historically connected habitats: habitat fragmentation effect in a carnivorous catfish Pelteobagrus fulvidraco from seven lakes in flood plain of the Yangtze River, China

    Directory of Open Access Journals (Sweden)

    Yao Wei J

    2009-04-01

    Full Text Available Abstract Background Habitat fragmentation may result in the reduction of diversity of parasite communities by affecting population size and dispersal pattern of species. In the flood plain of the Yangtze River in China, many lakes, which were once connected with the river, have become isolated since the 1950s from the river by the construction of dams and sluices, with many larger lakes subdivided into smaller ones by road embankments. These artificial barriers have inevitably obstructed the migration of fish between the river and lakes and also among lakes. In this study, the gastrointestinal helminth communities were investigated in a carnivorous fish, the yellowhead catfish Pelteobagrus fulvidraco, from two connected and five isolated lakes in the flood plain in order to detect the effect of lake fragmentation on the parasite communities. Results A total of 11 species of helminths were recorded in the stomach and intestine of P. fulvidraco from seven lakes, including two lakes connected with the Yangtze River, i.e. Poyang and Dongting lakes, and five isolated lakes, i.e. Honghu, Liangzi, Tangxun, Niushan and Baoan lakes. Mean helminth individuals and diversity of helminth communities in Honghu and Dongting lakes was lower than in the other five lakes. The nematode Procamallanus fulvidraconis was the dominant species of communities in all the seven lakes. No significant difference in the Shannon-Wiener index was detected between connected lakes (0.48 and isolated lakes (0.50. The similarity of helminth communities between Niushan and Baoan lakes was the highest (0.6708, and the lowest was between Tangxun and Dongting lakes (0.1807. The similarity was low between Dongting and the other lakes, and the similarity decreased with the geographic distance among these lakes. The helminth community in one connected lake, Poyang Lake was clustered with isolated lakes, but the community in Dongting Lake was separated in the tree. Conclusion The

  15. Communities of gastrointestinal helminths of fish in historically connected habitats: habitat fragmentation effect in a carnivorous catfish Pelteobagrus fulvidraco from seven lakes in flood plain of the Yangtze River, China.

    Science.gov (United States)

    Li, Wen X; Nie, Pin; Wang, Gui T; Yao, Wei J

    2009-04-27

    Habitat fragmentation may result in the reduction of diversity of parasite communities by affecting population size and dispersal pattern of species. In the flood plain of the Yangtze River in China, many lakes, which were once connected with the river, have become isolated since the 1950s from the river by the construction of dams and sluices, with many larger lakes subdivided into smaller ones by road embankments. These artificial barriers have inevitably obstructed the migration of fish between the river and lakes and also among lakes. In this study, the gastrointestinal helminth communities were investigated in a carnivorous fish, the yellowhead catfish Pelteobagrus fulvidraco, from two connected and five isolated lakes in the flood plain in order to detect the effect of lake fragmentation on the parasite communities. A total of 11 species of helminths were recorded in the stomach and intestine of P. fulvidraco from seven lakes, including two lakes connected with the Yangtze River, i.e. Poyang and Dongting lakes, and five isolated lakes, i.e. Honghu, Liangzi, Tangxun, Niushan and Baoan lakes. Mean helminth individuals and diversity of helminth communities in Honghu and Dongting lakes was lower than in the other five lakes. The nematode Procamallanus fulvidraconis was the dominant species of communities in all the seven lakes. No significant difference in the Shannon-Wiener index was detected between connected lakes (0.48) and isolated lakes (0.50). The similarity of helminth communities between Niushan and Baoan lakes was the highest (0.6708), and the lowest was between Tangxun and Dongting lakes (0.1807). The similarity was low between Dongting and the other lakes, and the similarity decreased with the geographic distance among these lakes. The helminth community in one connected lake, Poyang Lake was clustered with isolated lakes, but the community in Dongting Lake was separated in the tree. The similarity in the helminth communities of this fish in the flood

  16. Tides and lake-level variations in the great Patagonian lakes: Observations, modelling and geophysical implications.

    Science.gov (United States)

    Marderwald, Eric; Richter, Andreas; Horwath, Martin; Hormaechea, Jose Luis; Groh, Andreas

    2016-04-01

    In Patagonia, the glacial-isostatic adjustment (GIA) to past ice-mass changes (Ivins & James 2004; Klemann et al. 2007) is of particular interest in the context of the determination of the complex regional rheology related to plate subduction in a triple-junction constellation. To further complicate the situation, GIA is overlaid with load deformation not only due to present ice mass changes but also due to water-level changes in the lakes surrounding the icefields and the ocean surrounding Patagonia. These elastic deformations affect the determination of glacial-isostatic uplift rates from GPS observations (Dietrich et al. 2010; Lange et al. 2014). Observations of lake tides and their comparison with the theoretical tidal signal have been used previously to validate predictions of ocean tidal loading and have revealed regional deviations from conventional global elastic earth models (Richter et al. 2009). In this work we investigate the tides and lake-level variations in Lago Argentino, Lago Viedma, Lago San Martín/O'Higgins and Lago Buenos Aires/General Carrera. This allows us to test, among other things, the validity of tidal loading models. We present pressure tide-gauge records from two sites in Lago Argentino extending over 2.5 years (Richter et al. 2015). These observations are complemented by lake-level records provided by the Argentine National Hydrometeorological Network. Based on these lake-level time series the principal processes affecting the lake level are identified and quantified. Lake-level changes reflecting variations in lake volume are dominated by a seasonal cycle exceeding 1 m in amplitude. Lake-volume changes occur in addition with a daily period in response to melt water influx from surrounding glaciers. In Lago Argentino sporadic lake-volume jumps are caused by bursting of the ice dam of Perito Moreno glacier. Water movements in these lakes are dominated by surface seiches reaching 20 cm in amplitude. A harmonic tidal analysis of the lake

  17. National Dam Safety Program. Hilliard Estates Lake Dam (MO 20473), Osage - Gasconade River Basin, Greene County, Missouri. Phase I Inspection Report.

    Science.gov (United States)

    1981-03-01

    Tributary of the Little Pomme de Terre Date of Inspection: November 19, 1980 Hlilliard Estates Lake Dam was inspected by an interdiscip)- linary team... Terre River. The dam and lake are within the Strafford, Missouri 7.5 minute quadrangle sheet (Section 15, T3ON, R20W - latitude 37°19.1’ longitude

  18. Merging imagery and models for river current prediction

    Science.gov (United States)

    Blain, Cheryl Ann; Linzell, Robert S.; McKay, Paul

    2011-06-01

    To meet the challenge of operating in river environments with denied access and to improve the riverine intelligence available to the warfighter, advanced high resolution river circulation models are combined with remote sensing feature extraction algorithms to produce a predictive capability for currents and water levels in rivers where a priori knowledge of the river environment is limited. A River Simulation Tool (RST) is developed to facilitate the rapid configuration of a river model. River geometry is extracted from the automated processing of available imagery while minimal user input is collected to complete the parameter and forcing specifications necessary to configure a river model. Contingencies within the RST accommodate missing data such as a lack of water depth information and allow for ensemble computations. Successful application of the RST to river environments is demonstrated for the Snohomish River, WA. Modeled currents compare favorably to in-situ currents reinforcing the value of the developed approach.

  19. Model-based analysis of nutrient retention and management for a lowland river

    Directory of Open Access Journals (Sweden)

    D. Kneis

    2005-11-01

    Full Text Available In the context of the European Water Framework Directive options for improving the water quality of the lowland river Havel (Germany were assessed. The lower section of this river is actually a polytrophic river-lake system suffering from high external nutrient loading and exhibiting significant in-river turnover. In order to gain a better understanding of present conditions and to allow integrated scenarios of nutrient management to be evaluated the catchment models SWIM and ArcEGMO-Urban were coupled with a simple, newly developed nutrient TRAnsport Model (TraM. Using the TraM model, the retention of nitrogen and phosphorus in a 55 km reach of the Lower Havel River was quantified and its temporal variation was analyzed. It was examined that about 30% of the external nitrogen input to the Lower Havel is retained within the surveyed river section. A comparison of simulation results generated with and without consideration of phosphorus retention/release revealed that summer TP concentrations are currently increased by 100–200% due to internal loading. Net phosphorus release rates of about 20 mg P m−2 d-1 in late summer were estimated for the Havel lakes. Scenario simulations with lowered external nutrient inputs revealed that persistent phosphorus limitation of primary production cannot be established within the next decade. It was shown that a further reduction in nitrogen concentrations requires emissions to be reduced in all inflows. Though the TraM model needs further extension it proved to be appropriate for conducting integrated catchment and river modeling.

  20. Process-based distributed modeling approach for analysis of sediment dynamics in a river basin

    Directory of Open Access Journals (Sweden)

    M. A. Kabir

    2010-08-01

    Full Text Available Modeling of sediment dynamics for developing best management practices of reducing soil erosion and of sediment control has become essential for sustainable management of watersheds. Precise estimation of sediment dynamics is very important since soils are a major component of enormous environmental processes and sediment transport controls lake and river pollution extensively. Different hydrological processes govern sediment dynamics in a river basin, which are highly variable in spatial and temporal scales. This paper presents a process-based distributed modeling approach for analysis of sediment dynamics at river basin scale by integrating sediment processes (soil erosion, sediment transport and deposition with an existing process-based distributed hydrological model. In this modeling approach, the watershed is divided into an array of homogeneous grids to capture the catchment spatial heterogeneity. Hillslope and river sediment dynamic processes have been modeled separately and linked to each other consistently. Water flow and sediment transport at different surface grids and river nodes are modeled using one-dimensional kinematic wave approximation of Saint-Venant equations. The mechanics of sediment dynamics are integrated into the model using representative physical equations after a comprehensive review. The model has been tested on river basins in two different hydro climatic areas, the Abukuma River Basin, Japan and Latrobe River Basin, Australia. Sediment transport and deposition are modeled using Govers transport capacity equation. All spatial datasets, such as, Digital Elevation Model (DEM, land use and soil classification data, etc., have been prepared using raster "Geographic Information System (GIS" tools. The results of relevant statistical checks (Nash-Sutcliffe efficiency and R-squared value indicate that the model simulates basin hydrology and its associated sediment dynamics reasonably well. This paper presents the

  1. Process-based distributed modeling approach for analysis of sediment dynamics in a river basin

    Directory of Open Access Journals (Sweden)

    M. A. Kabir

    2011-04-01

    Full Text Available Modeling of sediment dynamics for developing best management practices of reducing soil erosion and of sediment control has become essential for sustainable management of watersheds. Precise estimation of sediment dynamics is very important since soils are a major component of enormous environmental processes and sediment transport controls lake and river pollution extensively. Different hydrological processes govern sediment dynamics in a river basin, which are highly variable in spatial and temporal scales. This paper presents a process-based distributed modeling approach for analysis of sediment dynamics at river basin scale by integrating sediment processes (soil erosion, sediment transport and deposition with an existing process-based distributed hydrological model. In this modeling approach, the watershed is divided into an array of homogeneous grids to capture the catchment spatial heterogeneity. Hillslope and river sediment dynamic processes have been modeled separately and linked to each other consistently. Water flow and sediment transport at different land grids and river nodes are modeled using one dimensional kinematic wave approximation of Saint-Venant equations. The mechanics of sediment dynamics are integrated into the model using representative physical equations after a comprehensive review. The model has been tested on river basins in two different hydro climatic areas, the Abukuma River Basin, Japan and Latrobe River Basin, Australia. Sediment transport and deposition are modeled using Govers transport capacity equation. All spatial datasets, such as, Digital Elevation Model (DEM, land use and soil classification data, etc., have been prepared using raster "Geographic Information System (GIS" tools. The results of relevant statistical checks (Nash-Sutcliffe efficiency and R–squared value indicate that the model simulates basin hydrology and its associated sediment dynamics reasonably well. This paper presents the

  2. Geochronology of recent lake sediments from Longgan Lake,middle reach of the Yangtze River,influenced by disturbance of human activities

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The impacts of human activities in Longgan Lake region on the distribution of 210Pb in lake sediment made it difficult to establish geochronological sequence. However, environmental proxies recorded these human activities and could be used as time marker to check 210Pb dating results. Based on the analysis of 210Pbexc distribution in cores LS-1 and LGL-1, and in combination with the human activities records in grain-size and element concentration, the sedimentation rates in the upper layers of these two cores were determined to be 0.19 and 0.23 cm/a respectively. The MAR (mass accumulation rates) of these two cores demonstrated that natural condition, such as precipitation and runoffs, led to the variation of MAR before human disturbance, and human activities controlled the sedimentary processes afterwards, which obviously reduced the particles influx into the lakes. During 1940s when human activity had not changed the water system within the catchment, 210Pb activity was abnormally strong in lakes along middle to lower reaches of the Yangtze River, which might be attributed to less precipitation and can be used as a time marker for geochronological research.

  3. LAKE 2.0: a model for temperature, methane, carbon dioxide and oxygen dynamics in lakes

    Science.gov (United States)

    Stepanenko, Victor; Mammarella, Ivan; Ojala, Anne; Miettinen, Heli; Lykosov, Vasily; Vesala, Timo

    2016-05-01

    A one-dimensional (1-D) model for an enclosed basin (lake) is presented, which reproduces temperature, horizontal velocities, oxygen, carbon dioxide and methane in the basin. All prognostic variables are treated in a unified manner via a generic 1-D transport equation for horizontally averaged property. A water body interacts with underlying sediments. These sediments are represented by a set of vertical columns with heat, moisture and CH4 transport inside. The model is validated vs. a comprehensive observational data set gathered at Kuivajärvi Lake (southern Finland), demonstrating a fair agreement. The value of a key calibration constant, regulating the magnitude of methane production in sediments, corresponded well to that obtained from another two lakes. We demonstrated via surface seiche parameterization that the near-bottom turbulence induced by surface seiches is likely to significantly affect CH4 accumulation there. Furthermore, our results suggest that a gas transfer through thermocline under intense internal seiche motions is a bottleneck in quantifying greenhouse gas dynamics in dimictic lakes, which calls for further research.

  4. An Archaeological Survey: Shoreline of Lake Darling and Proposed Burlington Dam. Flood Control Project Area, Upper Souris River, North Dakota

    Science.gov (United States)

    1978-01-01

    Burlington (1948), Carpio, N.E. (1949), Grano (1949), Grano , S.W. (1949), Greene (1949), Tolley (1948), Mouse River Park (1949), Mouse River ParkN.E. (1949...miles southeast of Grano , OZ North Dakota. The site is adjacent to Lake Darling’s east bank and also near the eastern boundary of the Upper Souris...miles south of Grano , North .7. 6 i 4 76 .9 . . -a s . 9 , . . aG =. . _ . ,, . . . ., . . 9. 9 . , , , " Dakota. The site lies on a flat 800 meters

  5. A dynamic multimedia environmental and bioaccumulation model for brominated flame retardants in Lake Huron and Lake Erie, USA.

    Science.gov (United States)

    Lim, Dong-Hee; Lastoskie, Christian M

    2011-05-01

    Polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) may pose a worldwide pollution problem because of their persistence, long-range transport capability, and predisposition to bioaccumulate. The ubiquitous presence of PBBs and PBDEs has heightened interest in determination of their fate. We report results for a fugacity-based dynamic environmental and bioaccumulation model of the fate of hexabromobiphenyl (hexaBB) discharged into the Saginaw Bay region of Lake Huron, USA. We calculated transient fugacity profiles of hexaBB in Lake Huron and Lake Erie water and sediment during the 1970s, 1980s, and 1990s. The hexaBB concentrations in the environmental compartments were used as inputs for a dynamic bioaccumulation model of Lake Huron and Lake Erie aquatic biota. The model results indicate that the sediment compartments of Lakes Huron and Erie serve as reservoirs for the accumulation and slow transfer of hexaBB to the food web constituents of these lakes. We present bioaccumulation factors (BAFs) and compare the predicted hexaBB concentrations in lake trout from the bioaccumulation model with measurements during the period 1980 to 2000. An uncertainty analysis for this model suggests that errors associated with input parameter uncertainty can be reduced by refining estimates of the sediment degradation half-life of hexaBB. The corroborated PBB model has carryover application for modeling the fate of polybrominated diphenyl ether (PBDE) contaminants in the Great Lakes. By fitting model outputs to field measurement data using the transformed least square fit method, we report estimations of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) emission rates into the Lake Huron and Lake Erie watershed areas.

  6. Landslide-generated tsunamis in a perialpine lake: Historical events and numerical models

    Science.gov (United States)

    Hilbe, Michael; Anselmetti, Flavio S.

    2014-05-01

    Many of the perialpine lakes in Central Europe - the large, glacier-carved basins formed during the Pleistocene glaciations of the Alps - have proven to be environments prone to subaquatic landsliding. Among these, Lake Lucerne (Switzerland) has a particularly well-established record of subaquatic landslides and related tsunamis. Its sedimentary archive documents numerous landslides over the entire Holocene, which have either been triggered by earthquakes, or which occurred apparently spontaneously, possibly due to rapid sediment accumulation on delta slopes. Due to their controlled boundary conditions and the possibility to be investigated on a complete basinal scale, such lacustrine tsunamis may be used as textbook analogons for their marine counterparts. Two events in the 17th century illustrate these processes and their consequences: In AD 1601, an earthquake (Mw ~ 5.9) led to widespread failure of the sediment drape covering the lateral slopes in several basins. The resulting landslides generated tsunami waves that reached a runup of several metres, as reported in historical accounts. The waves caused widespread damage as well as loss of lives in communities along the shores. In AD 1687, the apparently spontaneous collapse of a river delta in the lake led to similar waves that damaged nearby villages. Based on detailed information on topography, bathymetry and the geometry of the landslide deposits, numerical simulations combining two-dimensional, depth-averaged models for landslide propagation, as well as for tsunami generation, propagation and inundation, are able to reproduce most of the reported tsunami effects for these events. Calculated maximum runup of the waves is 6 to >10 m in the directly affected lake basins, but significantly less in neighbouring basins. Flat alluvial plains adjacent to the most heavily affected areas are inundated over distances of several hundred metres. Taken as scenarios for possible future events, these past events suggest

  7. Mathematical Modelling of Melt Lake Formation On An Ice Shelf

    Science.gov (United States)

    Buzzard, Sammie; Feltham, Daniel; Flocco, Daniela

    2016-04-01

    The accumulation of surface meltwater on ice shelves can lead to the formation of melt lakes. These structures have been implicated in crevasse propagation and ice-shelf collapse; the Larsen B ice shelf was observed to have a large amount of melt lakes present on its surface just before its collapse in 2002. Through modelling the transport of heat through the surface of the Larsen C ice shelf, where melt lakes have also been observed, this work aims to provide new insights into the ways in which melt lakes are forming and the effect that meltwater filling crevasses on the ice shelf will have. This will enable an assessment of the role of meltwater in triggering ice-shelf collapse. The Antarctic Peninsula, where Larsen C is situated, has warmed several times the global average over the last century and this ice shelf has been suggested as a candidate for becoming fully saturated with meltwater by the end of the current century. Here we present results of a 1-D mathematical model of heat transfer through an idealized ice shelf. When forced with automatic weather station data from Larsen C, surface melting and the subsequent meltwater accumulation, melt lake development and refreezing are demonstrated through the modelled results. Furthermore, the effect of lateral meltwater transport upon melt lakes and the effect of the lakes upon the surface energy balance are examined. Investigating the role of meltwater in ice-shelf stability is key as collapse can affect ocean circulation and temperature, and cause a loss of habitat. Additionally, it can cause a loss of the buttressing effect that ice shelves can have on their tributary glaciers, thus allowing the glaciers to accelerate, contributing to sea-level rise.

  8. The evolution of the River Nile. The buried saline rift lakes in Sudan—I. Bahr El Arab Rift, the Sudd buried saline lake

    Science.gov (United States)

    Salama, Ramsis B.

    The River Nile in Sudan, was during the Tertiary, a series of closed lake basins. Each basin occupying one of the major Sudanese rift systems (Salama, 1985a). In this paper evidence is presented for the presence of the buried saline Sudd Lake in Bahr El Arab rift. The thick Tertiary sediments filling the deep grabens were eroded from the elevated blocks; Jebel Marra, Darfur Dome, Nuba Mountains and the Nile-Congo Divide. The thick carbonate deposits existing at the faulted boundaries of Bahr El Arab defines the possible boundaries between the fresh and saline water bodies. The widespread presence of kanker nodules in the sediments was a result of continuous efflorescence, leaching and evaporative processes. The highly saline zone in the central part of the Sudd was formed through the same processes with additional sulphate being added by the oxidation of the hydrogen sulphide gases emanating from the oil fields.

  9. Limnology of Sawtooth Lakes - 1995: Effects of winter limnology and lake fertilization on potential production of Snake River sockeye salmon

    Energy Technology Data Exchange (ETDEWEB)

    Luecke, C.; Wurtsbaugh, W.A.; Budy, P.; Steinhart, G.B.; Slater, M.

    1996-05-01

    This Section II of the entire report describes the results of the limnological sampling conducted on Redfish, Altras, Pettit and Stanley Lakes from October 1994 through October 1995. Included are descriptions of winter limnological conditions and kokanee growth characteristics from 1993 to 1995, limnological conditions during the spring, summer and fall of 1995, comparison of characteristics among the four lakes; fertilization of Redfish Lake in 1995; effects of fertilization and effects of annual avriations in planktivorous fish abundance. Individual chapters and their subject areas are listed in following abstracts.

  10. PATTERNS AND TOURIST ACTIVITIES INDUCED BY THE UNDERGROUND RIVERS AND LAKES IN THE ARIEŞ BASIN UPSTREAM OF BURU

    Directory of Open Access Journals (Sweden)

    Marius CIGHER

    2011-11-01

    Full Text Available Patterns and tourist activities induced by the underground rivers and lakes in the Arieş basin upstream of Buru – The presence of carbonate deposits in the Arieş basin, upstream of Buru induced certain organization of groundwater resources. Depending on local genetic factors – geological, climatic, biotic, temporal, etc – the extension and characteristics of karst aquifers engenders exploitable hydro units in terms of tourism: underground rivers and lakes. Identification and analysis of morphometrical, morphological, quantitative, qualitative, dynamic and biotic characteristics have provided the approach to ranking the hydro entities. Forms and tourism activities are subsumed to the established typological categories: recreational and pleasure tourism and multipurpose tourism.

  11. Watershed modeling at the Savannah River Site.

    Energy Technology Data Exchange (ETDEWEB)

    Vache, Kellie [Oregon State University

    2015-04-29

    The overall goal of the work was the development of a watershed scale model of hydrological function for application to the US Department of Energy’s (DOE) Savannah River Site (SRS). The primary outcomes is a grid based hydrological modeling system that captures near surface runoff as well as groundwater recharge and contributions of groundwater to streams. The model includes a physically-based algorithm to capture both evaporation and transpiration from forestland.

  12. Age-0 Lost River sucker and shortnose sucker nearshore habitat use in Upper Klamath Lake, Oregon: A patch occupancy approach

    Science.gov (United States)

    Burdick, S.M.; Hendrixson, H.A.; VanderKooi, S.P.

    2008-01-01

    We examined habitat use by age-0 Lost River suckers Deltistes luxatus and shortnose suckers Chasmistes brevirostris over six substrate classes and in vegetated and nonvegetated areas of Upper Klamath Lake, Oregon. We used a patch occupancy approach to model the effect of physical habitat and water quality conditions on habitat use. Our models accounted for potential inconsistencies in detection probability among sites and sampling occasions as a result of differences in fishing gear types and techniques, habitat characteristics, and age-0 fish size and abundance. Detection probability was greatest during mid- to late summer, when water temperatures were highest and age-0 suckers were the largest. The proportion of sites used by age-0 suckers was inversely related to depth (range = 0.4-3.0 m), particularly during late summer. Age-0 suckers were more likely to use habitats containing small substrate (64 mm) and habitats with vegetation than those without vegetation. Relatively narrow ranges in dissolved oxygen, temperature, and pH prevented us from detecting effects of these water quality features on age-0 sucker nearshore habitat use.

  13. Challenges and opportunities for integrating lake ecosystem modelling approaches

    NARCIS (Netherlands)

    Mooij, W.M.; Trolle, D.; Jeppesen, E.; Arhonditsis, G.; Belolipetsky, P.; Chitamwebwa, D.B.R.; Degermendzhy, A.G.; DeAngelis, D.L.; De Senerpont Domis, L.N.; Downing, A.S.; Elliott, J.A.; Fragoso Jr., C.R.; Gaedke, U.; Genova, S.N.; Gulati, R.D.; Håkanson, L.; Hamilton, D.P.; Hipsey, M.R.; ‘t Hoen, P.J.; Hülsmann, S.; Los, F.J.; Makler-Pick, V.; Petzoldt, T.; Prokopkin, I.; Rinke, K.; Schep, S.A.; Tominaga, K.; Van Dam, A.A.; van Nes, E.H.; Wells, S.A.; Janse, J.H.

    2010-01-01

    A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others (‘reinventing t

  14. Challenges and opportunities for integrating lake ecosystem modelling approaches

    NARCIS (Netherlands)

    Mooij, W.M.; Trolle, D.; Jeppesen, E.; Arhonditsis, G.; Belolipetsky, P.V.; Chitamwebwa, D.B.R.; Degermendzhy, A.G.; DeAngelis, D.L.; Domis, L.N.D.; Downing, A.S.; Elliott, J.A.; Fragoso, C.R.; Gaedke, U.; Genova, S.N.; Gulati, R.D.; Hakanson, L.; Hamilton, D.P.; Hipsey, M.R.; Hoen, 't J.; Hulsmann, S.; Los, F.H.; Makler-Pick, V.; Petzoldt, T.; Prokopkin, I.G.; Rinke, K.; Schep, S.A.; Tominaga, K.; Dam, van A.A.; Nes, van E.H.; Wells, S.A.; Janse, J.H.

    2010-01-01

    A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others ('reinventing t

  15. Hydrologic and land-cover features of the Caloosahatchee River Basin, Lake Okeechobee to Franklin Lock, Florida

    Science.gov (United States)

    LaRose, Henry R.; McPherson, Benjamin F.

    1980-01-01

    The freshwater part of the Caloosahatchee River basin, Fla., from Franklin Lock to Lake Okeechobee, is shown at a scale of 1 inch equals 1 mile on an aerial photomosaic, dated January 1979. The basin is divided into 16 subbasins, and the land cover and land use in each subbasin are given. The basin is predominantly rangeland and agricultural land. Surface-water flow in the basin is largely controlled. Some selected data on water quality are given. (USGS)

  16. An improved lake model for climate simulations: Model structure, evaluation, and sensitivity analyses in CESM1

    Directory of Open Access Journals (Sweden)

    Zachary Subin

    2012-02-01

    Full Text Available Lakes can influence regional climate, yet most general circulation models have, at best, simple and largely untested representations of lakes. We developed the Lake, Ice, Snow, and Sediment Simulator(LISSS for inclusion in the land-surface component (CLM4 of an earth system model (CESM1. The existing CLM4 lake modelperformed poorly at all sites tested; for temperate lakes, summer surface water temperature predictions were 10–25uC lower than observations. CLM4-LISSS modifies the existing model by including (1 a treatment of snow; (2 freezing, melting, and ice physics; (3 a sediment thermal submodel; (4 spatially variable prescribed lakedepth; (5 improved parameterizations of lake surface properties; (6 increased mixing under ice and in deep lakes; and (7 correction of previous errors. We evaluated the lake model predictions of water temperature and surface fluxes at three small temperate and boreal lakes where extensive observational data was available. We alsoevaluated the predicted water temperature and/or ice and snow thicknesses for ten other lakes where less comprehensive forcing observations were available. CLM4-LISSS performed very well compared to observations for shallow to medium-depth small lakes. For large, deep lakes, the under-prediction of mixing was improved by increasing the lake eddy diffusivity by a factor of 10, consistent with previouspublished analyses. Surface temperature and surface flux predictions were improved when the aerodynamic roughness lengths were calculated as a function of friction velocity, rather than using a constant value of 1 mm or greater. We evaluated the sensitivity of surface energy fluxes to modeled lake processes and parameters. Largechanges in monthly-averaged surface fluxes (up to 30 W m22 were found when excluding snow insulation or phase change physics and when varying the opacity, depth, albedo of melting lake ice, and mixing strength across ranges commonly found in real lakes. Typical

  17. Modeling sediment transport in river networks

    Science.gov (United States)

    Wang, Xu-Ming; Hao, Rui; Huo, Jie; Zhang, Jin-Feng

    2008-11-01

    A dynamical model is proposed to study sediment transport in river networks. A river can be divided into segments by the injection of branch streams of higher rank. The model is based on the fact that in a real river, the sediment-carrying capability of the stream in the ith segment may be modulated by the undergone state, which may be erosion or sedimentation, of the i-1th and ith segments, and also influenced by that of the ith injecting branch of higher rank. We select a database about the upper-middle reach of the Yellow River in the lower-water season to test the model. The result shows that the data, produced by averaging the erosion or sedimentation over the preceding transient process, are in good agreement with the observed average in a month. With this model, the steady state after transience can be predicted, and it indicates a scaling law that the quantity of erosion or sedimentation exponentially depends on the number of the segments along the reach of the channel. Our investigation suggests that fluctuation of the stream flow due to random rainfall will prevent this steady state from occurring. This is owing to the phenomenon that the varying trend of the quantity of erosion or sedimentation is opposite to that of sediment-carrying capability of the stream.

  18. Hydrologic Setting and Conceptual Hydrologic Model of the Walker River Basin, West-Central Nevada

    Science.gov (United States)

    Lopes, Thomas J.; Allander, Kip K.

    2009-01-01

    The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. Between 1882 and 2008, agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-ft. Evaporative concentration increased dissolved solids from 2,500 to 17,000 milligrams per liter. The increase in salinity threatens the survival of the Lahontan cutthroat trout, a native species listed as threatened under the Endangered Species Act. This report describes the hydrologic setting of the Walker River basin and a conceptual hydrologic model of the relations among streams, groundwater, and Walker Lake with emphasis on the lower Walker River basin from Wabuska to Hawthorne, Nevada. The Walker River basin is about 3,950 square miles and straddles the California-Nevada border. Most streamflow originates as snowmelt in the Sierra Nevada. Spring runoff from the Sierra Nevada typically reaches its peak during late May to early June with as much as 2,800 cubic feet per second in the Walker River near Wabuska. Typically, 3 to 4 consecutive years of below average streamflow are followed by 1 or 2 years of average or above average streamflow. Mountain ranges are comprised of consolidated rocks with low hydraulic conductivities, but consolidated rocks transmit water where fractured. Unconsolidated sediments include fluvial deposits along the active channel of the Walker River, valley floors, alluvial slopes, and a playa. Sand and gravel deposited by the Walker River likely are discontinuous strata throughout the valley floor. Thick clay strata likely were deposited in Pleistocene Lake Lahontan and are horizontally continuous, except where strata have been eroded by the Walker River. At Walker Lake, sediments mostly are clay interbedded with alluvial slope, fluvial, and deltaic deposits along the lake margins. Coarse sediments form a multilayered, confined-aquifer system that could extend several miles from the shoreline

  19. Benthic algal assessment of ecological status in European lakes and rivers: Challenges and opportunities.

    Science.gov (United States)

    Poikane, Sandra; Kelly, Martyn; Cantonati, Marco

    2016-10-15

    This opinion paper introduces a special series of articles dedicated to freshwater benthic algae and their use in assessment and monitoring. This special series was inspired by talks presented at the 9th International Congress on the Use of Algae for Monitoring Rivers and Comparable Habitats (Trento, Italy, 2015), the latest of a series of meetings started in 1991. In this paper, we will first provide a brief overview of phytobenthos methods in Europe. Then, we will turn towards the 'dark side' of phytobenthos and describe four particular problems for phytobenthos assessment in the European Union: (1) over-reliance on a single group of algae (mostly diatoms) to the exclusion of other groups; (2) relatively low adoption of benthic algae for ecological assessments in lakes; (3) absence of measures of phytobenthos abundance; (4) approaches used to define boundaries between ecological classes. Following this, we evaluate the strengths and limitations of current phytobenthos assessment methods against 12 criteria for method evaluation addressing four areas: ecological rationale, performance, feasibility of implementation, and use in communication and management. Using these criteria, we identify and discuss three general challenges for those developing new methods for phytobenthos-based assessment: a weak ecological rationale and insufficient consideration of the role of phytobenthos as a diagnostic tool and for communicating ecosystem health beyond a narrow group of specialists. The papers in the special series allow a comparison with the situation and approaches in the USA, present new methods for the assessment of ecological status and acidification, provide tools for an improved management of headwaters and petrifying springs, discuss the utility of phytobenthos for lake assessments, and test the utility of functional measures (such as biofilm phosphorus uptake capacity, PUC).

  20. Location of the Thalweg of the Colorado River within Lake Mead, prior to the Impoundment of Lake Mead

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Lake Mead is a large interstate reservoir located in the Mojave Desert of southeastern Nevada and northwestern Arizona. It was impounded in 1935 by the construction...

  1. Macrophyte succession in floodplain lakes : spatio-temporal patterns in relation to river hydrology, lake morphology and management

    NARCIS (Netherlands)

    Geest, van G.J.

    2005-01-01

    Two questions are central to the work in this thesis: 1. What are the factors determining macrophyte composition in floodplain lakes along the Lower Rhine? 2. What advice can be given for design of future water bodies?

  2. The Chena River Watershed Hydrology Model

    Science.gov (United States)

    2012-04-01

    ER D C/ CR R EL T R -1 2 -1 The Chena River Watershed Hydrology Model C ol d R eg io n s R es ea rc h an d E n gi n ee ri n g La...14 Table 6. Estimated monthly ET using Hargreaves method and pan...using water balance method A generalized water balance for the Chena River watershed can be written as mS P S ET R     (3) where P

  3. Forming chemical composition of surface waters in the Arctic as "water - rock" interaction. Case study of lake Inari and river Paz

    Science.gov (United States)

    Mazukhina, Svetlana; Sandimirov, Sergey; Pozhilenko, Vladimir; Ivanov, Stanislav; Maksimova, Viktoriia

    2017-04-01

    Due to the depletion of fresh water supplies and the deterioration of their quality as a result of anthropogenic impact on the Arctic ecosystems, the research questions of forming surface and ground waters, their interactions with the rocks, development of the foundations for their rational use and protection are of great fundamental and practical importance. The aim of the work is to evaluate the influence of the chemical composition of rocks of the northern part of the Fennoscandian (Baltic) shield on forming surface waters chemical composition (Lake Inari, river Paz) using physical-chemical modeling (Chudnenko, 2010, Selector software package). River Paz (Paatsjoki) is the largest river in North Fennoscandia and flows through the territory of three countries - Finland, Russia and Norway. It originates from Lake Inari, which a large number of streams and rivers flow into, coming from the mountain range of the northern Finland (Maanselkä hill). Within the catchment of inflows feeding the lake Inari and river Paz in its upper flow there are mainly diverse early Precambrian metamorphic and intrusive rocks of the Lapland granulite belt and its framing, and to a lesser extent - various gneisses and migmatites with relicts of amphibolites, granitic gneisses, plagioclase and plagio- and plagiomicrocline granites, and quartz diorites of Inari terrane (Meriläinen, 1976, fig 1; Hörmann et al, 1980, fig 1; Geologicalmap, 2001). Basing on the techniques developed earlier (Mazukhina, 2012), and the data of monitoring of the chemical composition of surface waters and investigation of the chemical composition of the rocks, physical-chemical modeling (FCM) (Selector software package) was carried out. FCM includes 34 independent components (Al-B-Br-Ar-He-Ne-C-Ca-Cl-F-Fe-K-Mg-Mn-N-Na-P-S-Si-Sr-Cu-Zn-Ni-Pb-V-Ba-Co-Cr-Hg-As-Cd-H-O-e), 996 dependent components, of them 369 in aqueous solution, 76 in the gas phase, 111 liquid hydrocarbons, and 440 solid phases, organic and mineral

  4. Field experiment on biological contact oxidation process to treat polluted river water in the Dianchi Lake watershed

    Institute of Scientific and Technical Information of China (English)

    Lu LI; Shuguang XIE; Hui ZHANG; Donghui WEN

    2009-01-01

    In this study two types of biological contact oxidation processes (BCOP), a step-feed (SBCOP) unit and an inter-recycle (IBCOP) unit, were designed to investigate the treatment of heavily polluted river water.The Daqing River, which is the largest pollutant contributor to the Dianchi Lake, one of the most eutrophic freshwater lakes in China, was taken for the case study. It was found that the SBCOP had higher adaptability and better performance in the reduction of COD, TN, and TP,which made it applicable for the treatment of polluted river water entering the Dianchi Lake. Nitrification rate was observed to be greatly affected by the influent temperature.During each season, the nitrification in the SBCOP was higher than that in the IBCOP. TN removal efficiency in the SBCOP was higher than that in the IBCOP during the winter and spring but poorer during the summer, possibly due to the inhibition of denitrification by higher dissolved oxygen level in the summer. Moreover, symbiotic algae-bacteria growth may be conducive to the removal of pollutants.

  5. Updating river basin models with radar altimetry

    DEFF Research Database (Denmark)

    Michailovsky, Claire Irene B.

    response of a catchment to meteorological forcing. While river discharge cannot be directly measured from space, radar altimetry (RA) can measure water level variations in rivers at the locations where the satellite ground track and river network intersect called virtual stations or VS. In this PhD study...... been between 10 and 35 days for altimetry missions until now. The location of the VS is also not necessarily the point at which measurements are needed. On the other hand, one of the main strengths of the dataset is its availability in near-real time. These characteristics make radar altimetry ideally...... suited for use in data assimilation frameworks which combine the information content from models and current observations to produce improved forecasts and reduce prediction uncertainty. The focus of the second and third papers of this thesis was therefore the use of radar altimetry as update data...

  6. Technical Note: Automatic river network generation for a physically-based river catchment model

    OpenAIRE

    2010-01-01

    SHETRAN is a physically-based distributed modelling system that gives detailed simulations in time and space of water flow and sediment and solute transport in river catchments. Standard algorithms for the automatic generation of river channel networks from digital elevation data are impossible to apply in SHETRAN and other similar models because the river channels are assumed to run along the edges of grid cells. In this work a new algorithm for the automatic generation of a river cha...

  7. Technical Note: Automatic river network generation for a physically-based river catchment model

    OpenAIRE

    2010-01-01

    SHETRAN is a physically-based distributed modelling system that gives detailed simulations in time and space of water flow and sediment and solute transport in river catchments. Standard algorithms for the automatic generation of river channel networks from digital elevation data are impossible to apply in SHETRAN and other similar models because the river channels are assumed to run along the edges of grid cells. In this work a new algorithm for the automatic generation of a river channel ne...

  8. Lake Biel sediment record during the last 7500 years and impact of the Aare river deviation in 1878 AD.

    Science.gov (United States)

    Jeannet, Alice; Corella, Juan Pablo; Reusch, Anna; Kremer, Katrina; Girardclos, Stéphanie

    2013-04-01

    Lake sediments are excellent archives of environmental and climate changes as well as human impact on lake- and river-systems. Lake Biel is a medium-sized peri-alpine lake (Switzerland) with a maximum depth of 74 m and lies at 429 m asl. Our study focuses on the south-west basin, where the lake sedimentation was naturally mainly controlled by autochthonous sedimentation, and is now, since the artificial Aare river deviation through the Hagneck canal in 1878 AD, under the strong influence of water and sediment input from its catchment. A 10.05-m-long composite sediment sequence, cored in 2011 at 52 m water depth, was built from two cores retrieved with an Uwitec system. The cored sedimentary sequence begins in 1975 and spans the last 7500 years, as dated by seven 14C analyses and 210Pb/137Cs activity profiles. Magnetic susceptibility and density were measured with a Geotek MSCL at 0.5 cm resolution, granulometry with a CILAS grain sizer every 10 cm and X-ray fluorescence measurements were carried out using an Avaatech core scanner at 1-cm resolution. Lake Biel sediment record is subdivided in four main units. The lowest Unit A (651-1005 cm; 7355 to 5075 BP), with dark greyish clayey silty laminated layers and sedimentation rates between 0.10 to 0.29 cm/yr, shows stable low values for almost all proxies, excepted for allochtonous elements which increase between 7000-6000 BP. By analogy with Unit C facies (see below), Unit A is interpreted as influenced by the Aare river which probably flew into the south-west basin at that time. Unit B1 (651-343 cm, 5075 to 2036 BP) has lower sedimentation rate (0.10 cm/yr), high Ca/Ti ratio, light sediment color, constant clayey silty grain size and varying elemental profiles which point to the dominant influence of autochtonous lake processes influenced by climate. From the beginning of Unit B2 (343-147 cm, 2036 to 1878 AD) sediment grain size increases which possibly reflects a human influence over the lake system. The greatest

  9. Sediment Transport in the Bill Williams River and Turbidity in Lake Havasu During and Following Two High Releases from Alamo Dam, Arizona, in 2005 and 2006

    Science.gov (United States)

    Wiele, Stephen M.; Hart, Robert J.; Darling, Hugh L.; Hautzinger, Andrew B.

    2009-01-01

    Discharges higher than are typically released from Alamo Dam in west-central Arizona were planned and released in 2005, 2006, 2007, and 2008 to study the effects of these releases on the Bill Williams River and Lake Havasu, into which the river debouches. Sediment concentrations and water discharges were measured in the Bill Williams River, and turbidity, temperature, and dissolved oxygen were measured in Lake Havasu during and after experimental releases in 2005 and 2006 from Alamo Dam. Data from such releases will support ongoing ecological studies, improve environmentally sensitive management of the river corridor, and support the development of a predictive relationship between the operation of Alamo Dam and downstream flows and their impact on Lake Havasu and the Colorado River. Elevated discharges in the Bill Williams River mobilize more sediment than during more typical dam operation and can generate a turbidity plume in Lake Havasu. The intakes for the Central Arizona Project, which transfers Colorado River water to central and southern Arizona, are near the mouth of the Bill Williams River. Measurement of the turbidity and the development of the plume over time consequently were important components of the study. In this report, the measurements of suspended sediment concentration and discharges in the Bill Williams River and of turbidity in Lake Havasu are presented along with calculations of silt and sand loads in the Bill Williams River. Sediment concentrations were varied and likely dependent on a variable supply. Sediment loads were calculated at the mouth of the river and near Planet, about 10 km upstream from the mouth for the 2005 release, and they indicate that a net increase in transport of silt and a net decrease in the transport of sand occurred in the reach between the two sites.

  10. Projecting the future levels of Lake Victoria

    Science.gov (United States)

    Vanderkelen, Inne; van Lipzig, Nicole; Thiery, Wim

    2017-04-01

    Lake Victoria directly sustains 30 million people living in its basin and 200 000 fishermen operating from its shores. As the one of the two sources of the Nile River, it also supports natural resources that impact the livelihood of over 300 million people living in the Nile basin. The outlet to the Nile is controlled by two hydropower dams. The water balance of Lake Victoria is controlled both by climatic conditions (precipitation and evaporation) and human management (dam outflow). Future climate simulations with a high resolution coupled lake-land-atmosphere model project decreasing mean precipitation and increasing evaporation over Lake Victoria. As these two are important factors in the water balance of Lake Victoria, these projected changes may induce a drop in future levels of Lake Victoria. Moreover, as Lake Victoria is also a relatively shallow lake, lake surface area may decrease as well. Here we present a water balance model for Lake Victoria that provides lake level and extent as output. We first force our model with observational input (new satellite products providing high quality precipitation and evaporation data) and evaluate it using measured lake levels. The skill of the model is subsequently assessed by forcing it with present-day regional climate simulations (CORDEX evaluation simulations). In a third step the future lake levels and surface area changes of Lake Victoria are simulated by forcing the model with CORDEX projections under RCP4.5 and 8.5. Finally, the role of human decisions regarding future dam outflow are investigated.

  11. Population models of burrowing mayfly recolonization in Western Lake Erie

    Science.gov (United States)

    Madenjian, C.P.; Schloesser, D.W.; Krieger, K.A.

    1998-01-01

    Burrowing mayflies, Hexagenia spp. (H. limbata and H. rigida), began recolonizing western Lake Erie during the 1990s. Survey data for mayfly nymph densities indicated that the population experienced exponential growth between 1991 and 1997. To predict the time to full recovery of the mayfly population, we fitted logistic models, ranging in carrying capacity from 600 to 2000 nymphs/m2, to these survey data. Based on the fitted logistic curves, we forecast that the mayfly population in western Lake Erie would achieve full recovery between years 1998 and 2000, depending on the carrying capacity of the western basin. Additionally, we estimated the mortality rate of nymphs in western Lake Erie during 1994 and then applied an age-based matrix model to the mayfly population. The results of the matrix population modeling corroborated the exponential growth model application in that both methods yielded an estimate of the population growth rate, r, in excess of 0.8 yr-1. This was the first evidence that mayfly populations are capable of recolonizing large aquatic ecosystems at rates comparable with those observed in much smaller lentic ecosystems. Our model predictions should prove valuable to managers of power plant facilities along the western basin in planning for mayfly emergences and to managers of the yellow perch (Perca flavescens) fishery in western Lake Erie.

  12. An agent-based model for water management and planning in the Lake Naivasha basin, Kenya

    Science.gov (United States)

    van Oel, Pieter; Mulatu, Dawit; Odongo, Vincent; Onyando, Japheth; Becht, Robert; van der Veen, Anne

    2013-04-01

    A variety of human and natural processes influence the ecological and economic state of the Lake Naivasha basin. The ecological wealth and recent economic developments in the area are strongly connected to Lake Naivasha which supports a rich variety of flora, mammal and bird species. Many human activities depend on clean freshwater from the lake whereas recently the freshwater availability of good quality is seriously influenced by water abstractions and the use of fertilizers in agriculture. Management alternatives include those aiming at limiting water abstractions and fertilizer use. A possible way to achieve reduced use of water and fertilizers is the introduction of Payment for Environmental Services (PES) schemes. As the Lake Naivasha basin and its population have experienced increasing pressures various disputes and disagreements have arisen about the processes responsible for the problems experienced, and the effectively of management alternatives. Beside conflicts of interest and disagreements on responsibilities there are serious factual disagreements. To share scientific knowledge on the effects of the socio-ecological system processes on the Lake Naivasha basin, tools may be used that expose information at temporal and spatial scales that are meaningful to stakeholders. In this study we use a spatially-explicit agent-based modelling (ABM) approach to depict the interactions between socio-economic and natural subsystems for supporting a more sustainable governance of the river basin resources. Agents consider alternative livelihood strategies and decide to go for the one they perceive as likely to be most profitable. Agents may predict and sense the availability of resources and also can observe economic performance achieved by neighbouring agents. Results are presented at the basin and subbasin level to provide relevant knowledge to Water Resources Users Associations which are important collective forums for water management through which PES schemes

  13. Ancient lakes, Pleistocene climates and river avulsions structure the phylogeography of a large but little-known rock scorpion from the Mojave and Sonoran deserts

    Science.gov (United States)

    Graham, Matthew R.; Wood, Dustin A.; Henault, Jonathan A.; Valois, Zachary J.; Cushing, Paula E.

    2017-01-01

    Recent syntheses of phylogeographical data from terrestrial animals in the Mojave and Sonoran deserts have revealed a complex history of geologic and climatic vicariance events. We studied the phylogeography of Smeringurus vachoni to see how vicariance events may have impacted a large, endemic rock scorpion. Additionally, we used the phylogeographical data to examine the validity of two subspecies of S. vachoni that were described using unconventional morphological characters. Phylogenetic, network and SAMOVA analyses indicate that S. vachoni consists of 11 clades mostly endemic to isolated desert mountain ranges. Molecular clock estimates suggest that clades diversified between the Miocene and early Pleistocene. Species distribution models predict a contraction of suitable habitat during the last glacial maximum. Landscape interpolations and Migrate-n analyses highlight areas of gene flow across the Colorado River. Smeringurus vachoni does not comprise two subspecies. Instead, the species represents at least 11 mitochondrial clades that probably diversified by vicariance associated with Pleistocene climate changes and formation of ancient lakes along the Colorado River corridor. Gene flow appears to have occurred from west to east across the Colorado River during periodic river avulsions.

  14. Modelling the Loktak Lake Basin to Assess Human Impact on Water Resources

    Science.gov (United States)

    Eliza, K.

    2015-12-01

    Loktak Lake is an internationally important, Ramsar designated, fresh water wetland system in the state of Manipur, India. The lake was also listed under Montreux Record on account of the ecological modifications that the lake system has witnessed over time. A characteristic feature of this lake is the extensive occurrence of coalesced, naturally or otherwise, vegetative masses floating over it. A contiguous 40 km2 area of Phumdis, as these vegetative masses are locally referred to, also constitutes the only natural home of the endemic and endangered species of Manipur's brow-antlered deer popularly known as Sangai. Appropriately notified as Keibul Lamjao National Park by Government of India, this natural feature is known to be the world's largest floating park. Water quality and sediment deposition on account of soil erosion in its catchments are some of the emerging concerns along with a reported enhanced frequency and duration of flooding of the shore areas, reduced fish catch within a visibly deteriorated overall natural ecosystem. Disturbances of watershed processes, command area management practices, ineffective as indeed largely absent, waste management practices and management interventions linked to the Loktak Hydroelectric Project are often cited as the principal triggers that are seen to be responsible for the damage. An effective management protocol for the Lake requires a rigorous understanding of its hydrobiology and eco-hydrodynamics. The present study is carried out to establish such a characterization of the various rivers systems draining directly into the Lake using MIKE SHE, MIKE 11 HD and MIKE 11 ECO Lab modelling platforms. Water quality modelling was limited to dissolved oxygen (DO), biological oxygen demand (BOD) and water temperature. Model calibration was done using the available measured water quality data. The derived results were then investigated for causal correlation with anthropogenic influences to assess human impact on water

  15. Interactive lakes in the Canadian Regional Climate Model, version 5: the role of lakes in the regional climate of North America

    Directory of Open Access Journals (Sweden)

    Bernard Dugas

    2012-02-01

    Full Text Available Two one-dimensional (1-D column lake models have been coupled interactively with a developmental version of the Canadian Regional Climate Model. Multidecadal reanalyses-driven simulations with and without lakes revealed the systematic biases of the model and the impact of lakes on the simulated North American climate.The presence of lakes strongly influences the climate of the lake-rich region of the Canadian Shield. Due to their large thermal inertia, lakes act to dampen the diurnal and seasonal cycle of low-level air temperature. In late autumn and winter, ice-free lakes induce large sensible and latent heat fluxes, resulting in a strong enhancement of precipitation downstream of the Laurentian Great Lakes, which is referred to as the snow belt.The FLake (FL and Hostetler (HL lake models perform adequately for small subgrid-scale lakes and for large resolved lakes with shallow depth, located in temperate or warm climatic regions. Both lake models exhibit specific strengths and weaknesses. For example, HL simulates too rapid spring warming and too warm surface temperature, especially in large and deep lakes; FL tends to damp the diurnal cycle of surface temperature. An adaptation of 1-D lake models might be required for an adequate simulation of large and deep lakes.

  16. Braided rivers, lakes and sabkhas of the upper Triassic Cifuncho formation, Atacama region, Chile

    Science.gov (United States)

    Suárez, M.; Bell, C. M.

    1994-01-01

    A 1,000-m-thickness of Upper Triassic (to possibly Hettangian) sediments of the Cifuncho Formation are exposed in the coastal Cordillera of the Atacama Region, Chile. These coarse-grained clastic terrigenous strata are interpreted as the deposits of braided rivers, ephemeral lakes, sabkhas and volcaniclastic alluvial fans. They include conglomerates, pebbly sandstones, fine to medium-grained sandstones and thin, finely-laminated limestones. Halite hopper-casts are abundant in sandstones near the top of the section. Approximately 90% of the clastic detritus was derived from an upper Paleozoic metasedimentary accretionary complex located to the west. Andesitic debris flow and pyroclastic flow deposits occur near the base of the sequence. Isolated tuff intercalations and an ignimbritic lava flow occur higher in the section. The great thickness of coarse-grained and ill-sorted clastic sediments suggests deposition in an actively subsiding basin, probably a graben, adjacent to rising highlands. Overlying Hettangian-Sinemurian marine sediments were deposited by a transgression which occurred during a world-wide lowstand. This suggests that thermal subsidence followed the Triassic rifting.

  17. Global distribution of dissolved organic matter along the aquatic continuum: Across rivers, lakes and oceans

    DEFF Research Database (Denmark)

    Massicotte, Philippe; Asmala, Eero; Stedmon, Colin

    2017-01-01

    Based on an extensive literature survey containing more than 12,000 paired measurements of dissolved organic carbon (DOC) concentrations and absorption of chromophoric dissolved organic matter (CDOM) distributed over four continents and seven oceans, we described the global distribution and trans......Based on an extensive literature survey containing more than 12,000 paired measurements of dissolved organic carbon (DOC) concentrations and absorption of chromophoric dissolved organic matter (CDOM) distributed over four continents and seven oceans, we described the global distribution...... and transformation of dissolved organic matter (DOM) along the aquatic continuum across rivers and lakes to oceans. A strong log-linear relationship (R2 = 0.92) between DOC concentration and CDOM absorption at 350 nm was observed at a global scale, but was found to be ecosystem-dependent at local and regional...... scales. Our results reveal that as DOM is transported towards the oceans, the robustness of the observed relation decreases rapidly (R2 from 0.94 to 0.44) indicating a gradual decoupling between DOC and CDOM. This likely reflects the decreased connectivity between the landscape and DOM along the aquatic...

  18. Morphology of ruffe (Gymnocephalus cernuus) protolarvae from the St. Louis River, Lake Superior

    Science.gov (United States)

    French, John R. P.; Edsall, Thomas A.

    1992-01-01

    We describe hatching and the morphological and meristic characteristics of 2.5-5.6 mm long ruffe protolarvae (Gymnocephalus cernuus). Eggs and sperm from St. Louis River ruffe were mixed, producing fertilized eggs that were 0.9-1.2 mm in diameter. Newly hatched protolarvae were 2.5-3.2 mm long. They had 14-15 preanal and 23-24 postanal myomeres, a continuous finfold of even width, unpigmented eyes, and a large anterior oil globule in the yolk sac, and the head deflected over the yolk sac. Pectoral fin buds appeared on the dorsal side of the yolk sac 5 hours after hatching. Two-day-old protolarvae had fully pigmented eyes, and the head was free from the yolk sac. Three-day-old protolarvae were 3.9-4.3 mm long and possessed opercula, gills, pectoral fins, and a functional jaw. Feeding and swimming began about one week after hatching when the yolk sac was almost completely absorbed. Protolarvae grew rapidly at 20-22 degrees C and were 4.9-5.6 mm long after 13 days. Newly hatched ruffe protolarvae are distinguished from other Lake Superior percids by having the fewest preanal myomeres (14-15), the head deflected over the yolk sac, continuous finfold of even width, and a total length of less than 4.0 mm.

  19. Evaluation of nutrient load transferred from Sarca river into Garda lake; Stima del carico di nutrienti trasportato dal fiume Sarca nel Lago di Garda

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, F. [Istituto Agrario, S. Michele all' Adige, TN (Italy); Fravezzi, L. [Agenzia Provinciale Protezione Ambiente, Trient (Italy)

    2000-02-01

    River Sarca (catchment surface=1046 Km{sup 2} max altitude=3556 m, min altitude=70 m, mean annual discharge=30 m{sup 3}) is the main tributary of the Lake Garda, the largest subalpine lake in Northern Italy (area=370 Km{sup 2,} catchment surface (included lake surface)=2260 Km{sup 2}, volume=49 Km{sup 3}, max depth=346 m). During 1996-97 a large series of hourly samples has been taken at the estuary's mouth and used to estimate the nutrient loading. Analytical and probabilistic methods are used to relate the data series to the trophic state of the lake. The results are compared with previous theoretical models (L.E.M.- Loading Evaluation Model) and related to dangerous load levels established by OECD. [Italian] L'indagine ha interessato particolarmente le concentrazioni ed il carico organico ed inorganico di azoto e fosforo che affluisce dal bacino del Fiume Sarca (superficie del bacino=1046 km{sup 2,} quota massima=3556 m, quota minima=70 m, portata media annua=30 m{sup 3}) nel Lago di Garda (area=370 km{sup 2}, area del bacino (lago incluso)=2260 km{sup 2}, volume=49 km{sup 3}, profondita' massima=346 m); lo studio si e' svolto nel periodo 1996-1997, con campionamenti presso la foce utilizzando strumentazione per prelievi in continuo nell'arco di una giornata anche in occasione di fenomeni di piena. I risultati hanno permesso di stabilire delle relazioni tra carico e portata liquida e di stimare i quantitativi di nutrienti trasportati a lago e di confrontarli con i risultati di altre indagini (L.E.M. - Loading Evaluation Model) e di valutarne gli effetti attraverso modelli predittivi (OECD).

  20. [Ecotourism exploitation model in Bita Lake Natural Reserve of Yunnan].

    Science.gov (United States)

    Yang, G; Wang, Y; Zhong, L

    2000-12-01

    Bita lake provincial natural reserve is located in Shangri-La region of North-western Yunnan, and was set as a demonstrating area for ecotourism exploitation in 1998. After a year's exploitation construction and half a year's operation as a branch of the 99' Kunming International Horticulture Exposition to accept tourists, it was proved that the ecotourism demonstrating area attained four integrated functions of ecotourism, i.e., tourism, protection, poverty clearing and environment education. Five exploitation and management models including function zoned exploitation model, featured tourism communication model signs system designing model, local Tibetan family reception model and environmental monitoring model, were also successful, which were demonstrated and spreaded to the whole province. Bita lake provincial natural reserve could be a good sample for the ecotourism exploitation natural reserves of the whole country.

  1. Comparative study of water quality of rivers used for raw water supply & ex-mining lakes in Perak, Malaysia

    Science.gov (United States)

    Orji, K. U.; Sapari, N.; Yusof, K. W.; Asadpour, R.; Olisa, E.

    2013-06-01

    Ex-mining lakes are seldom used as sources of raw water for the treatment of public water supply due to the general view that they are highly polluted. This study examined the water quality of these lakes, compared and contrasted them to the water quality of the rivers used for Perak drinking water supply. Ten water samples were analyzed from different ex-mining lakes. Two water samples were from Kinta and Perak rivers. They were analyzed for physico-chemical properties such as temperature, pH, EC, TDS, SO42- COD, Cl- Na+ Fe, As, and Pb. The results showed that temperature varied from 28.1°C to 34.1°C, pH 6.2 to 9.0, EC 55 to 400 μs/cm, turbidity 5.6 to 74.2 NTU, TDS 36.8 to 268mg/l, Cl- 0.483 to 3.339mg/l, SO42- 0.051 to 15.307mg/l, Na 0.669 to 3.668mg/l, Fe 0 to 0.14mg/l, As 0 to 0.004mg/l, and Pb 0.019 to 0.075mg/l. All the samples were highly turbid, had slightly high concentration of Pb, and had common water quality problem. The ex-mining lakes can also be used to supply water after treatment since these rivers are already being used by the Metropolitan Utilities Corporation for water treatment. The ex-mining pools can be used as alternative sources of drinking water supply to the people of Perak.

  2. Summer nitrate uptake and denitrification in an upper Mississippi River backwater lake: The role of rooted aquatic vegetation

    Science.gov (United States)

    Kreiling, Rebecca M.; Richardson, W.B.; Cavanaugh, J.C.; Bartsch, L.A.

    2011-01-01

    In-stream nitrogen processing in the Mississippi River has been suggested as one mechanism to reduce coastal eutrophication in the Gulf of Mexico. Aquatic macrophytes in river channels and flood plain lakes have the potential to temporarily remove large quantities of nitrogen through assimilation both by themselves and by the attached epiphyton. In addition, rooted macrophytes act as oxygen pumps, creating aerobic microsites around their roots where coupled nitrification-denitrification can occur. We used in situ 15N-NO3- tracer mesocosm experiments to measure nitrate assimilation rates for macrophytes, epiphyton, and microbial fauna in the sediment in Third Lake, a backwater lake of the upper Mississippi River during June and July 2005. We measured assimilation over a range of nitrate concentrations and estimated a nitrate mass balance for Third Lake. Macrophytes assimilated the most nitrate (29.5 mg N m-2 d-1) followed by sediment microbes (14.4 mg N m-2 d-1) and epiphytes (5.7 mg N m-2d-1. Assimilation accounted for 6.8% in June and 18.6% in July of total nitrate loss in the control chambers. However, denitrification (292.4 mg N m-2 d-1) is estimated to account for the majority (82%) of the nitrate loss. Assimilation and denitrification rates generally increased with increasing nitrate concentration but denitrification rates plateaued at about 5 mg N L-1. This suggests that backwaters have the potential to remove a relatively high amount of nitrate but will likely become saturated if the load becomes too large. ?? 2010 US Government.

  3. Structure and seasonal dynamics of phytoplankton and zooplankton in Lake Azili, small Lake of the pond of River Ouémé, “Benin”

    Directory of Open Access Journals (Sweden)

    Arsène Mathieu Houssou

    2015-04-01

    Full Text Available The early reaction of the plankton communities to environmental changes makes it a useful tool for monitoring the pollution of aquatic environments. Lake Azili is a small water body, the majority of which is strongly influenced by river Ouémé during the floods time. Its ecosystem is one of the most important for the country, due to its rich biodiversity, especially that of halieutics. By following the evolution of its health, due to the strong anthropological pressure, this study aims to estimate the structure and the dynamics of its planktonic biodiversity and to assess its current state. It was carried out for seven months between May to November, 2012, according to the hydrological seasons of Benin. Plankton samplings were monthly, taken in a vertical sense from the lake, from all depths, using plankton net. The diversity indices were calculated for the compartment of zooplankton, that of phytoplankton being a preliminary evaluation. A total of 51 species of phytoplankton and 36 zooplankton species were inventoried. Instability is observed in the seasonal structure of both communities, especially for the period of transition between the floods and the floods recession. Due to the specific composition and the diversity, the ecosystem of Lake Azili is perturbed.

  4. Snow and ice on Bear Lake (Alaska – sensitivity experiments with two lake ice models

    Directory of Open Access Journals (Sweden)

    Tido Semmler

    2012-03-01

    Full Text Available Snow and ice thermodynamics of Bear Lake (Alaska are investigated with a simple freshwater lake model (FLake and a more complex snow and ice thermodynamic model (HIGHTSI. A number of sensitivity experiments have been carried out to investigate the influence of snow and ice parameters and of different complexity on the results. Simulation results are compared with observations from the Alaska Lake Ice and Snow Observatory Network. Adaptations of snow thermal and optical properties in FLake can largely improve accuracy of the results. Snow-to-ice transformation is important for HIGHTSI to calculate the total ice mass balance. The seasonal maximum ice depth is simulated in FLake with a bias of −0.04 m and in HIGHTSI with no bias. Correlation coefficients between ice depth measurements and simulations are high (0.74 for FLake and 0.9 for HIGHTSI. The snow depth simulation can be improved by taking into account a variable snow density. Correlation coefficients for surface temperature are 0.72 for FLake and 0.81 for HIGHTSI. Overall, HIGHTSI gives slightly more accurate surface temperature than FLake probably due to the consideration of multiple snow and ice layers and the expensive iteration calculation procedure.

  5. Does water level affect benthic macro-invertebrates of a marginal lake in a tropical river-reservoir transition zone?

    Science.gov (United States)

    Zerlin, R A; Henry, R

    2014-05-01

    Benthic macro-invertebrates are important components of freshwater ecosystems which are involved in ecological processes such as energy transfer between detritus and consumers and organic matter recycling. The aim of this work was to investigate the variation in organism richness, diversity and density of benthic fauna during the annual cycle in Camargo Lake, a lake marginal to Paranapanema River, southeast Brazil. The correlation of environmental factors with community attributes of the macro-benthic fauna was assessed. Since Camargo Lake is connected to the river, we tested the hypothesis that water level variation is the main regulating factor of environmental variables and of the composition and abundance of benthic macro-invertebrates. The results indicated that lake depth varied with rainfall, being the highest at the end of the rising water period and the lowest at the beginning of this period. The sediment granulometry was more heterogeneous at the bottom of the lake by the end of the high water period. The benthic macro-invertebrate fauna was composed by 15 taxa. The Diptera order was represented by seven taxa and had greater richness in relation to other taxa. This group was responsible for 60% of the total abundance of organisms, followed by Ephemeroptera (22%) and Anellida (16%). Significant differences were observed over time in total richness and, in density of Narapa bonettoi, Chaoborus, Ablabesmyia gr. annulata, Chironomus gigas, Larsia fittkau, and Procladius sp. 2. Total taxa richness correlated negatively with water pH, transparency, conductivity, and bottom water oxygen. Higher positive correlations were found between the densities of some taxa and bottom water oxygen, conductivity and very fine sand, silt + clay of sediment, while negative correlations were recorded with organic matter, and fine, medium and coarse sand, bottom water temperature, mean temperature and rainfall. The significant temporal difference in water level was associated

  6. Archaeological Survey and Testing for the Upstream Work. Big Stone Lake-Whetstone River Project Area,

    Science.gov (United States)

    1975-09-01

    Hubbard County Crookston Site, Polk County Grand Portage, Lake County Archaeological Field Research (continued) Orwell Site, Ottertail County Lake... George I. Quimby. 1960. Minnesota History, Vol. No. . p. 174. 1961 Review: Indian Life in the Upper Great Lakes, 11,000 B.C. to A.D. 1800 by George I

  7. Water quality modelling of Lis River, Portugal.

    Science.gov (United States)

    Vieira, Judite; Fonseca, André; Vilar, Vítor J P; Boaventura, Rui A R; Botelho, Cidália M S

    2013-01-01

    The aim of the study was to predict the impact of flow conditions, discharges and tributaries on the water quality of Lis River using QUAL2Kw model. Calibration of the model was performed, based on data obtained in field surveys carried out in July 2004 and November 2006. Generally the model fitted quite well the experimental data. The results indicated a decrease of water quality in the downstream area of Lis River, after the confluence of Lena, Milagres and Amor tributaries, as a result of discharges of wastewaters containing degradable organics, nutrients and pathogenic organisms from cattle-raising wastewaters, domestic effluents and agricultural runoff. The water quality criteria were exceeded in these areas for dissolved oxygen, biochemical oxygen demand, total nitrogen and faecal coliforms. Water quality modelling in different scenarios showed that the impact of tributaries on the quality of Lis River water was quite negligible and mainly depends on discharges, which are responsible by an increase of almost 45, 13 and 44 % of ultimate carbonaceous biochemical oxygen demand (CBOD(u)), ammonium nitrogen and faecal coliforms, for winter simulation, and 23, 33 and 36 % for summer simulation, respectively, when compared to the real case scenario.

  8. Lateral and vertical channel movement and potential for bed-material movement on the Madison River downstream from Earthquake Lake, Montana

    Science.gov (United States)

    Chase, Katherine J.; McCarthy, Peter M.

    2012-01-01

    and to investigate the potential for bed material movement along the same reach. The purpose of this report is to present information about the lateral and vertical movement of the Madison River from 1970 to 2006 for a 1-mile reach downstream from Earthquake Lake and for Raynolds Pass Bridge, and to provide an analysis of the potential for bed-material movement so that MADTAC can evaluate the applicability of the previously determined threshold streamflow for initiation of damaging erosion. As part of this study channel cross sections originally surveyed by the USGS in 1971 were resurveyed in 2006. Incremental channel-movement distances were determined by comparing the stream centerlines from 14 aerial photographs taken between 1970 and 2006. Depths of channel incision and aggregation were determined by comparing the 2006 and 1971 cross-section and water-surface data. Particle sizes of bed and bank materials were measured in 2006 and 2008 using the pebble-count method and sieve analyses. A one-dimensional hydraulic-flow model (HEC-RAS) was used to calculate mean boundary-shear stresses for various streamflows; these calculated boundary-shear stresses were compared to calculated critical-shear stresses for the bed materials to determine the potential for bed-material movement. A comparison of lateral channel movement distances with annual peak streamflows shows that streamflows higher than the 3,500-ft3/s threshold were followed by lateral channel movement except from 1991 to 1992 and possibly from 1996 to 1997. However, it was not possible to discern whether the channel moved gradually or suddenly, or in response to one peak flow, to several peak flows, or to sustained flows. The channel moved between 2002 and 2005 even when streamflows were less than the threshold streamflow of 3,500 ft3/s. Comparisons of cross sections and aerial photographs show that the channel has moved laterally and incised and aggraded to varying degrees. The channel has developed meander bends

  9. A model for landscape development in terms of shoreline displacement, sediment dynamics, lake formation, and lake choke-up processes

    Energy Technology Data Exchange (ETDEWEB)

    Brydsten, Lars [Umeaa University, Dept. of Ecology and Environmental Science (Sweden)

    2006-12-15

    This project expands on the study 'A mathematical model for lake ontogeny in terms of filling with sediments and macrophyte vegetation' published in SKB TR-04-09. As the title suggests, this older model focuses on lakes (existing and future lakes). This newer study extends the model to examine progress of terrestrial objects such as mires or arable land. Furthermore, this newer model could simulate progress of the areas close to the objects. These areas are divided according to their watershed boundaries. If two or more objects are situated along the same brook, the lower situated area is defined as its catchments minus the catchments of the closest higher situated object. The model encourages the study of an object situated in the sea from the time of deglaciation (c. 10,000 BP) to the time for the object due to positive shore displacement is situated on land or that a lake object has progressed to a wetland, however not longer than 18,000 AP. The model focuses on the object and its location in 100-year steps. The model is written in VisualBasic and is divided into two modules, a marine module and a lake module. The marine module deals with shoreline displacement, erosion and accumulation of postglacial fine-grained sediments and erosion of glacial clay. Inputs to the marine module are a digital elevation model (DEM), a digital map showing the extension of the objects and a marine quaternary map. The two maps are in raster formats with exactly the same formats (extension and cell sizes) as the DEM. For each time step the water depths at each pixel are calculated using a shore displacement equation. Next, the water depth changes due to sediment dynamics are calculated using the following rules; accumulation of fine-grained sediments are allowed if the pixel is situated within a future lake object; erosion of fine-grained sediment is allowed if the pixel is not within a future lake object and the marine quaternary map shows occurrence of postglacial

  10. Reservoir Sediment Management Workshop for Tuttle Creek Lake and Perry Lake Reservoirs in the Kansas River Basin

    Science.gov (United States)

    2015-03-01

    kick in the seat of the pants: Using your explorer, artist , judge, and warrior to be more creative. New York, NY: Harper and Row Publishers...accumulation. Neighboring Milford Lake could offer more supply yield with increased inflow. A technique to evaluate this approach is to perform a

  11. Simple model for river network evolution

    Energy Technology Data Exchange (ETDEWEB)

    Leheny, R.L. [The James Franck Institute and The Department of Physics, The University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637 (United States)

    1995-11-01

    We simulate the evolution of a drainage basin by erosion from precipitation and avalanching on hillslopes. The avalanches create a competition in growth between neighboring basins and play the central role in driving the evolution. The simulated landscapes form drainage systems that share many qualitative features with Glock`s model for natural network evolution and maintain statistical properties that characterize real river networks. We also present results from a second model with a modified, mass conserving avalanche scheme. Although the terrains from these two models are qualitatively dissimilar, their drainage networks share the same general evolution and statistical features.

  12. Modelling hourly rates of evaporation from small lakes

    Directory of Open Access Journals (Sweden)

    R. J. Granger

    2011-01-01

    Full Text Available The paper presents the results of a field study of open water evaporation carried out on three small lakes in Western and Northern Canada. In this case small lakes are defined as those for which the temperature above the water surface is governed by the upwind land surface conditions; that is, a continuous boundary layer exists over the lake, and large-scale atmospheric effects such as entrainment do not come into play. Lake evaporation was measured directly using eddy covariance equipment; profiles of wind speed, air temperature and humidity were also obtained over the water surfaces. Observations were made as well over the upwind land surface.

    The major factors controlling open water evaporation were examined. The study showed that for time periods shorter than daily, the open water evaporation bears no relationship to the net radiation; the wind speed is the most significant factor governing the evaporation rates, followed by the land-water temperature contrast and the land-water vapour pressure contrast. The effect of the stability on the wind field was demonstrated; relationships were developed relating the land-water wind speed contrast to the land-water temperature contrast. The open water period can be separated into two distinct evaporative regimes: the warming period in the Spring, when the land is warmer than the water, the turbulent fluxes over water are suppressed; and the cooling period, when the water is warmer than the land, the turbulent fluxes over water are enhanced.

    Relationships were developed between the hourly rates of lake evaporation and the following significant variables and parameters (wind speed, land-lake temperature and humidity contrasts, and the downwind distance from shore. The result is a relatively simple versatile model for estimating the hourly lake evaporation rates. The model was tested using two independent data sets. Results show that the modelled evaporation follows the observed values

  13. Do High-elevation Lakes Record Variations in Snowfall and Atmospheric Rivers in the Sierra Nevada of California?

    Science.gov (United States)

    Ashford, J.; Sickman, J. O.; Lucero, D. M.

    2014-12-01

    Understanding the underlying causes of interannual variation in snowfall and extreme hydrologic events in the Sierra Nevada is hampered by short instrumental records and the difficulties in reconstructing climate using a traditional paleo-record such as tree-rings. New paleo proxies are needed to provide a record of snowpack water content and extreme precipitation events over millennial timescales which can be used to test hypotheses regarding teleconnections between Pacific climate variability and water supply and flood risk in California. In October 2013 we collected sediment cores from Pear Lake (z = 27 m), an alpine lake in Sequoia National Park. The cores were split and characterized by P-wave velocity, magnetic susceptibility and density scanning. Radiocarbon dates indicate that the Pear Lake cores contain a 13.5K yr record of lake sediment. In contrast to other Sierra Nevada lakes previously cored by our group, high-resolution scanning revealed alternating light-dark bands (~1 mm to 5 mm thick) for most of the Pear Lake core length. This pattern was interrupted at intervals by homogenous clasts (up to 75 mm thick) ranging in grain size from sand to gravel up to 1 cm diameter. We hypothesize that the light-dark banding results from the breakdown of persistent hypolimnetic anoxia during spring snowmelt and autumn overturn. We speculate that the thicknesses of the dark bands are controlled by the duration of anoxia which in turn is controlled by the volume and duration of snowmelt. The sand to gravel sized clasts are most likely associated with extreme precipitation events resulting from atmospheric rivers intersecting the southern Sierra Nevada. We hypothesize that centimeter-sized clasts are deposited in large avalanches and that the sands are deposited in large rain events outside of the snow-cover period.

  14. Modelled present and future thaw lake area expansion/contraction trends throughout the continuous permafrost zone

    Directory of Open Access Journals (Sweden)

    Y. Mi

    2014-07-01

    Full Text Available Thaw lakes and drained lake basins are a dominant feature of Arctic lowlands. Thaw lakes are a source of the greenhouse gas methane (CH4, which is produced under anaerobic conditions, while drained lake basins are carbon sinks due to sedimentation. Besides feedbacks on climate, the development of thaw lakes due to the melt-out of ground ice and subsequent ground subsidence, can have significant impacts on the regional morphology, hydrology, geophysics and biogehemistry. Permafrost degradation as a result of climate warming, which is proceeding considerably faster in high latitude regions than the global average, could lead to either an increases in lake area due to lake expansion, or decrease due to lake drainage. However, which process will dominate is elusive. Therefore understanding thaw lake dynamics and quantifying the feedbacks related to thaw lake expansion and contraction are urgent questions to solve. We apply a stochastic model, THAWLAKE, on four representative Arctic sites, to reproduce recent lake dynamics (1963–2012 and predict for the future changes under various anticipated climate scenarios. The model simulations of current thaw lake cycles and expansion rates are comparable with data. Future lake expansions are limited by lake drainage. We suggest further improvements in the area of enhancing the hydrology component, and operation on larger scales to gauge the impacts on lacustrine morphology and greenhouse gas emissions.

  15. Investigation of the dramatic changes in lake level of the Bosten Lake in northwestern China

    Science.gov (United States)

    Guo, Mengjing; Wu, Wei; Zhou, Xiaode; Chen, Yongmin; Li, Jing

    2015-01-01

    Bosten Lake, located in the arid region of northwest China, is the largest inland freshwater lake in China. Water resources in Bosten Lake are of great importance for the regional drinking water supply, agricultural irrigation, and economic development of Xinjiang province. In this study, the dynamics of the lake level in Bosten Lake were investigated from 1956 to 2010. We found that the lake level experienced three different periods of change due to the combined influences of climate variation and human activities. Generally, the lake level has shown a significant downward trend since the first observation started in 1956 and dropped to its lowest level in 1987. Thereafter, the lake level presented a continuous upward trend and rose to its highest value in 2002. Then, the level decreased dramatically from 2002 to 2010. A water balance model and the climate elasticity method were used to estimate the reasons for the lake level changes of Bosten Lake. The results showed that an increase in lake evaporation led to the continuous decrease in lake level from 1958 to 1987. Then, human-controlled lake outflow and increasing lake inflow together led to the increase in lake level from 1988 to 2002. During 2003 to 2010, the emergency project of transferring water to Tarim River led to the increase in lake outflow, while the lake inflow obviously decreased because of a decrease in precipitation. These factors resulted in a sharp decrease in the lake level from 2003 to 2010. The changes in lake level indicate changes in available water resources from Bosten Lake. This reason for the analysis of the change in lake level in this study is to support the water resources management of Bosten Lake.

  16. An Integrated Hydrological and Water Management Study of the Entire Nile River System - Lake Victoria to Nile Delta

    Science.gov (United States)

    Habib, Shahid; Zaitchik, Benjamin; Alo, Clement; Ozdogan, Mutlu; Anderson, Martha; Policelli, Fritz

    2011-01-01

    The Nile basin River system spans 3 million km(exp 2) distributed over ten nations. The eight upstream riparian nations, Ethiopia, Eretria, Uganda, Rwanda, Burundi, Congo, Tanzania and Kenya are the source of approximately 86% of the water inputs to the Nile, while the two downstream riparian countries Sudan and Egypt, presently rely on the river's flow for most of the their needs. Both climate and agriculture contribute to the complicated nature of Nile River management: precipitation in the headwaters regions of Ethiopia and Lake Victoria is variable on a seasonal and inter-annual basis, while demand for irrigation water in the arid downstream region is consistently high. The Nile is, perhaps, one of the most difficult trans-boundary water issue in the world, and this study would be the first initiative to combine NASA satellite observations with the hydrologic models study the overall water balance in a to comprehensive manner. The cornerstone application of NASA's Earth Science Research Results under this project are the NASA Land Data Assimilation System (LDAS) and the USDA Atmosphere-land Exchange Inverse (ALEXI) model. These two complementary research results are methodologically independent methods for using NASA observations to support water resource analysis in data poor regions. Where an LDAS uses multiple sources of satellite data to inform prognostic simulations of hydrological process, ALEXI diagnoses evapotranspiration and water stress on the basis of thermal infrared satellite imagery. Specifically, this work integrates NASA Land Data Assimilation systems into the water management decision support systems that member countries of the Nile Basin Initiative (NBI) and Regional Center for Mapping of Resources for Development (RCMRD, located in Nairobi, Kenya) use in water resource analysis, agricultural planning, and acute drought response to support sustainable development of Nile Basin water resources. The project is motivated by the recognition that

  17. Measuring water level in rivers and lakes from lightweight Unmanned Aerial Vehicles

    Science.gov (United States)

    Bandini, Filippo; Jakobsen, Jakob; Olesen, Daniel; Reyna-Gutierrez, Jose Antonio; Bauer-Gottwein, Peter

    2017-05-01

    The assessment of hydrologic dynamics in rivers, lakes, reservoirs and wetlands requires measurements of water level, its temporal and spatial derivatives, and the extent and dynamics of open water surfaces. Motivated by the declining number of ground-based measurement stations, research efforts have been devoted to the retrieval of these hydraulic properties from spaceborne platforms in the past few decades. However, due to coarse spatial and temporal resolutions, spaceborne missions have several limitations when assessing the water level of terrestrial surface water bodies and determining complex water dynamics. Unmanned Aerial Vehicles (UAVs) can fill the gap between spaceborne and ground-based observations, and provide high spatial resolution and dense temporal coverage data, in quick turn-around time, using flexible payload design. This study focused on categorizing and testing sensors, which comply with the weight constraint of small UAVs (around 1.5 kg), capable of measuring the range to water surface. Subtracting the measured range from the vertical position retrieved by the onboard Global Navigation Satellite System (GNSS) receiver, we can determine the water level (orthometric height). Three different ranging payloads, which consisted of a radar, a sonar and an in-house developed camera-based laser distance sensor (CLDS), have been evaluated in terms of accuracy, precision, maximum ranging distance and beam divergence. After numerous flights, the relative accuracy of the overall system was estimated. A ranging accuracy better than 0.5% of the range and a maximum ranging distance of 60 m were achieved with the radar. The CLDS showed the lowest beam divergence, which is required to avoid contamination of the signal from interfering surroundings for narrow fields of view. With the GNSS system delivering a relative vertical accuracy better than 3-5 cm, water level can be retrieved with an overall accuracy better than 5-7 cm.

  18. Genetic and Phenotypic Catalog of Native Resident Trout of the interior Columbia River Basin : FY-2001 Report : Populations in the Wenatchee, Entiat, Lake Chelan and Methow River Drainages.

    Energy Technology Data Exchange (ETDEWEB)

    Trotter, Patrick C.

    2001-10-01

    The 1994 Fish and Wildlife Program of the Northwest Power Planning Council specifies the recovery and preservation of population health of native resident fishes of the Columbia River Basin. Among the native resident species of concern are interior rainbow trout of the Columbia River redband subspecies Oncorhynchus mykiss gairdneri 1 and westslope cutthroat trout O. clarki lewisi. The westslope cutthroat trout has been petitioned for listing under the U. S. Endangered Species Act (American Wildlands et al. 1997). Before at-risk populations can be protected, their presence and status must be established. Where introgression from introduced species is a concern, as in the case of both westslope cutthroat trout and redband rainbow trout, genetic issues must be addressed as well. As is true with native trout elsewhere in the western United States (Behnke 1992), most of the remaining pure populations of these species in the Columbia River Basin are in relatively remote headwater reaches. The objective of this project was to photo-document upper Columbia Basin native resident trout populations in Washington, and to ascertain their species or subspecies identity and relative genetic purity using a nonlethal DNA technique. FY-2001 was year three (and final year) of a project in which we conducted field visits to remote locations to seek out and catalog these populations. In FY-2001 we worked in collaboration with the Wenatchee National Forest to catalog populations in the Wenatchee, Entiat, Lake Chelan, and Methow River drainages of Washington State.

  19. Response to heavy, non-floating oil spilled in a Great Lakes river environment: a multiple-lines-of-evidence approach for submerged oil assessment and recovery

    Science.gov (United States)

    Dollhopf, Ralph H.; Fitzpatrick, Faith A.; Kimble, Jeffrey W.; Capone, Daniel M.; Graan, Thomas P.; Zelt, Ronald B.; Johnson, Rex

    2014-01-01

    The Enbridge Line 6B pipeline release of diluted bitumen into the Kalamazoo River downstream of Marshall, MI in July 2010 is one of the largest freshwater oil spills in North American history. The unprecedented scale of impact and massive quantity of oil released required the development and implementation of new approaches for detection and recovery. At the onset of cleanup, conventional recovery techniques were employed for the initially floating oil and were successful. However, volatilization of the lighter diluent, along with mixing of the oil with sediment during flooded, turbulent river conditions caused the oil to sink and collect in natural deposition areas in the river. For more than three years after the spill, recovery of submerged oil has remained the predominant operational focus of the response. The recovery complexities for submerged oil mixed with sediment in depositional areas and long-term oil sheening along approximately 38 miles of the Kalamazoo River led to the development of a multiple-lines-of-evidence approach comprising six major components: geomorphic mapping, field assessments of submerged oil (poling), systematic tracking and mapping of oil sheen, hydrodynamic and sediment transport modeling, forensic oil chemistry, and net environmental benefit analysis. The Federal On-Scene Coordinator (FOSC) considered this information in determining the appropriate course of action for each impacted segment of the river. New sources of heavy crude oils like diluted bitumen and increasing transportation of those oils require changes in the way emergency personnel respond to oil spills in the Great Lakes and other freshwater ecosystems. Strategies to recover heavy oils must consider that the oils may suspend or sink in the water column, mix with fine-grained sediment, and accumulate in depositional areas. Early understanding of the potential fate and behavior of diluted bitumen spills when combined with timely, strong conventional recovery methods can

  20. Habitat quality and recruitment success of cui-ui in the Truckee River downstream of Marble Bluff Dam, Pyramid Lake, Nevada

    Science.gov (United States)

    Scoppettone, G. Gary; Rissler, Peter H.; Salgado, J. Antonio; Harry, Beverly

    2013-01-01

    We compared cui-ui (Chasmistes cujus) recruitment from two reaches of the Truckee River with histories of severe erosional downcutting caused by a decline in Pyramid Lake surface elevation. In 1975, Marble Bluff Dam (MBD) was constructed 5 kilometers upstream of the extant mouth of the Truckee River to stabilize the upstream reach of the river; the downstream reach of the river remained unstable and consequently unsuitable for cui-ui recruitment. By the early 2000s, there was a decrease in the Truckee River’s slope from MBD to Pyramid Lake after a series of wet years in the 1990s. This was followed by changes in river morphology and erosion abatement. These changes led to the question as to cui-ui recruitment potential in the Truckee River downstream of MBD. In 2012, more than 7,000 cui-ui spawners were passed upstream of MBD, although an indeterminate number of cui-ui spawned downstream of MBD. In this study, we compared cui-ui recruitment upstream and downstream of MBD during a Truckee River low-flow year (2012). Cui-ui larvae emigration to Pyramid Lake began earlier and ended later downstream of MBD. A greater number of cui-ui larvae was produced downstream of MBD than upstream. This also was true for native Tahoe sucker (Catostomus tahoensis) and Lahontan redside (Richardsonius egregius). The improved Truckee River stability downstream of MBD and concomitant cui-ui recruitment success is attributed to a rise in Pyramid Lake's surface elevation. A decline in lake elevation may lead to a shift in stream morphology and substrate composition to the detriment of cui-ui reproductive success as well as the reproductive success of other native fishes.

  1. Development of a zoning-based environmental-ecological-coupled model for lakes to assess lake restoration effect

    Science.gov (United States)

    Xu, Mengjia; Zou, Changxin; Zhao, Yanwei

    2017-04-01

    Environmental/ecological models are widely used for lake management as they provide a means to understand physical, chemical and biological processes in highly complex ecosystems. Most research focused on the development of environmental (water quality) and ecological models, separately. Limited studies were developed to couple the two models, and in these limited coupled models, a lake was regarded as a whole for analysis (i.e., considering the lake to be one well-mixed box), which was appropriate for small-scale lakes and was not sufficient to capture spatial variations within middle-scale or large-scale lakes. This paper seeks to establish a zoning-based environmental-ecological-coupled model for a lake. The Baiyangdian Lake, the largest freshwater lake in Northern China, was adopted as the study case. The coupled lake models including a hydrodynamics and water quality model established by MIKE21 and a compartmental ecological model used STELLA software have been established for middle-sized Baiyangdian Lake to realize the simulation of spatial variations of ecological conditions. On the basis of the flow field distribution results generated by MIKE21 hydrodynamics model, four water area zones were used as an example for compartmental ecological model calibration and validation. The results revealed that the developed coupled lake models can reasonably reflected the changes of the key state variables although there remain some state variables that are not well represented by the model due to the low quality of field monitoring data. Monitoring sites in a compartment may not be representative of the water quality and ecological conditions in the entire compartment even though that is the intention of compartment-based model design. There was only one ecological observation from a single monitoring site for some periods. This single-measurement issue may cause large discrepancies particularly when sampled site is not representative of the whole compartment. The

  2. Freshwater polychaetes (Manayunkia speciosa) near the Detroit River, western Lake Erie: Abundance and life‐history characteristics

    Science.gov (United States)

    Schloesser, Donald W.; Malakauskas, David M.; Malakauskas, Sarah J.

    2016-01-01

    Freshwater polychaetes are relatively rare and little-studied members of the benthos of lakes and rivers. We studied one polychaete species (Manayunkia speciosa) in Lake Erie near the mouth of the Detroit River. Abundances at one site were determined between 1961 and 2013 and life‐history characteristics at two sites were determined seasonally (March–November) in 2009–2010 and 2012–2013. Life‐history characteristics included abundances, length‐frequency distributions, presence/absence of constructed tubes, sexual maturity, and number and maturation of young of year (YOY) in tubes. Long-term abundances decreased in successive time periods between 1961 and 2003 (mean range = 57,570 to 2583/m2) but few changes occurred between 2003 and 2013 (mean = 5007/m2; range/y = 2355–8216/m2). Seasonal abundances varied substantially between sites and years, but overall, abundances were low in March–April, high in May–August, and low in September–November. Although reproduction was continuous throughout warmer months, en masse recruitment, as revealed by length–frequency distributions, occurred in a brief period late‐June to mid-July, and possibly in early-September. All life history characteristics, including tube construction, were dependent on water temperatures (> 5 °C in spring and < 15 °C in fall). These results generally agree with and complement laboratory studies of M. speciosa in the Pacific Northwest where M. speciosa hosts parasites that cause substantial fish mortalities. Although abundance ofM. speciosa near the mouth of the Detroit River was 33-fold lower in 2013 than it was in 1961, this population has persisted for five decades and, therefore, has the potential to harbor parasites that may cause fish mortalities in the Great Lakes.

  3. Thermodynamic Modeling of Savannah River Evaporators

    Energy Technology Data Exchange (ETDEWEB)

    Weber, C.F.

    2001-08-02

    A thermodynamic model based on the code SOLGASMIX is developed to calculate phase equilibrium in evaporators and related tank wastes at the Savannah River Site (SRS). This model uses the Pitzer method to calculate activity coefficients, and many of the required Pitzer parameters have been determined in the course of this work. Principal chemical species in standard SRS simulant solutions are included, and the temperature range for most parameters has been extended above 100 C. The SOLGASMIX model and calculations using the code Geochemists Workbench are compared to actual solubility data including silicate, aluminate, and aluminosilicate solutions. In addition, SOLGASMIX model calculations are also compared to transient solubility data involving SRS simulant solutions. These comparisons indicate that the SOLGASMIX predictions closely match reliable data over the range of temperature and solution composition expected in the SRS evaporator and related tanks. Predictions using the Geochemists Workbench may be unreliable, due primarily to the use of an inaccurate activity coefficient model.

  4. Simulation of the effects of different inflows on hydrologic conditions in Lake Houston with a three-dimensional hydrodynamic model, Houston, Texas, 2009–10

    Science.gov (United States)

    Rendon, Samuel H.; Lee, Michael T.

    2015-12-08

    Lake Houston, an important water resource for the Houston, Texas, area, receives inflows from seven major tributaries that compose the San Jacinto River Basin upstream from the reservoir. The effects of different inflows from the watersheds drained by these tributaries on the residence time of water in Lake Houston and closely associated physical and chemical properties including lake elevation, salinity, and water temperature are not well known. Accordingly, the U.S. Geological Survey (USGS), in cooperation with the City of Houston, developed a three-dimensional hydrodynamic model of Lake Houston as a tool for evaluating the effects of different inflows on residence time of water in the lake and associated physical and chemical properties. The Environmental Fluid Dynamics Code (EFDC), a grid-based, surface-water modeling package for simulating three-dimensional circulation, mass transport, sediments, and biogeochemical processes, was used to develop the model of Lake Houston. The Lake Houston EFDC model was developed and calibrated by using 2009 data and verified by using 2010 data. Three statistics (mean error, root mean square error, and the Nash-Sutcliffe model efficiency coefficient) were used to evaluate how well the Lake Houston EFDC model simulated lake elevation, salinity, and water temperature. The residence time of water in reservoirs is associated with various physical and chemical properties (including lake elevation, salinity, and water temperature). Simulated and measured lake-elevation values were compared at USGS reservoir station 08072000 Lake Houston near Sheldon, Tex. The accuracy of simulated salinity and water temperature values was assessed by using the salinity (computed from measured specific conductance) and water temperature at two USGS monitoring stations: 295826095082200 Lake Houston south Union Pacific Railroad Bridge near Houston, Tex., and 295554095093401 Lake Houston at mouth of Jack’s Ditch near Houston, Tex. Specific conductance

  5. Hydrology and Glacier-Lake-Outburst Floods (1987-2004) and Water Quality (1998-2003) of the Taku River near Juneau, Alaska

    Science.gov (United States)

    Neal, Edward G.

    2007-01-01

    The Taku River Basin originates in British Columbia, Canada, and drains an area of 6,600 square miles at the U.S. Geological Survey's Taku River gaging station. Several mines operated within the basin prior to 1957, and mineral exploration has resumed signaling potential for future mining developments. The U.S. Geological Survey in cooperation with the Douglas Indian Association, Alaska Department of Environmental Conservation, and the U.S. Environmental Protection Agency conducted a water-quality and flood-hydrology study of the Taku River. Water-quality sampling of the Taku River from 1998 through 2003 established a baseline for assessing potential effects of future mining operations on water quality. The annual mean discharge of the Taku River is 13,700 cubic feet per second. The monthly mean discharge ranges from a minimum of 1,940 cubic feet per second in February to a maximum of 34,400 cubic feet per second in June. Nearly 90 percent of the annual discharge is from May through November. The highest spring discharges are sourced primarily from snowmelt and moderate discharges are sustained throughout the summer by glacial meltwaters. An ice cover usually forms over the Taku River in December persisting through the winter into March and occasionally into April. Glacier-lake-outburst floods originating from two glacier-dammed lakes along the margin of the Tulsequah Glacier in British Columbia, Canada, are the source of the greatest peak discharges on the Taku River. The largest flood during the period of record was 128,000 cubic feet per second on June 25, 2004, resulting from an outburst of Lake No Lake. Lake No Lake is the larger of the two lakes. The outburst-flood contribution to peak discharge was 80,000 cubic feet per second. The volume discharged from Lake No Lake is relatively consistent indicating drainage may be triggered when the lake reaches a critical stage. This suggests prediction of the timing of these outburst floods might be possible if lake

  6. Results from the Italian participation in the International Co-operative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes (ICP Waters

    Directory of Open Access Journals (Sweden)

    Gabriele A. TARTARI

    2000-02-01

    Full Text Available This paper describes the research activity carried out by the Istituto Italiano di Idrobiologia of the CNR, on behalf of the Ministero dell'Ambiente, Servizio Inquinamento Atmosferico e Acustico, in the context of the Italian participation in the International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes (ICP Waters. Atmospheric deposition chemistry shows that nitrate increased and sulphate decreased in the 70's and 80's, while acidity started to decrease in the early 90's. The studied rivers and lakes show variations in sulphate and nitrate in agreement with those of atmospheric deposition. Alkalinity is mainly determined by watershed geo-lithology and is always present in the studied lakes and streams; the lowest values of 0-10 μeq l-1 are measured in the high altitude Lake Paione Superiore, which however shows an increasing trend of alkalinity and pH.

  7. Progress towards Continental River Dynamics modeling

    Science.gov (United States)

    Yu, Cheng-Wei; Zheng, Xing; Liu, Frank; Maidment, Daivd; Hodges, Ben

    2017-04-01

    The high-resolution National Water Model (NWM), launched by U.S. National Oceanic and Atmospheric Administration (NOAA) in August 2016, has shown it is possible to provide real-time flow prediction in rivers and streams across the entire continental United States. The next step for continental-scale modeling is moving from reduced physics (e.g. Muskingum-Cunge) to full dynamic modeling with the Saint-Venant equations. The Simulation Program for River Networks (SPRNT) provides a computational approach for the Saint-Venant equations, but obtaining sufficient channel bathymetric data and hydraulic roughness is seen as a critical challenge. However, recent work has shown the Height Above Nearest Drainage (HAND) method can be applied with the National Elevation Dataset (NED) to provide automated estimation of effective channel bathymetry suitable for large-scale hydraulic simulations. The present work examines the use of SPRNT with the National Hydrography Dataset (NHD) and HAND-derived bathymetry for automated generation of rating curves that can be compared to existing data. The approach can, in theory, be applied to every stream reach in the NHD and thus provide flood guidance where none is available. To test this idea we generated 2000+ rating curves in two catchments in Texas and Alabama (USA). Field data from the USGS and flood records from an Austin, Texas flood in May 2015 were used as validation. Large-scale implementation of this idea requires addressing several critical difficulties associated with numerical instabilities, including ill-posed boundary conditions generated in automated model linkages and inconsistencies in the river geometry. A key to future progress is identifying efficient approaches to isolate numerical instability contributors in a large time-space varying solution. This research was supported in part by the National Science Foundation under grant number CCF-1331610.

  8. KARYOMORPHOLOGY OF TH E PHILIPPINE ROCK GOBY, Glossogobius giuris (GOBIIDAE FROM LAKE TAAL AND SOME RIVERS OF CAVITE, LUZON ISLAND

    Directory of Open Access Journals (Sweden)

    JOSE A. ORDONEZ

    2003-01-01

    Full Text Available The karyomorphology of Glossogobius giuris (Gobiidae obtained from Lake Taal and some rivers of Cavite in Luzon Island, Philippines was described. Metaphase chromosome analysis (colchicine-sodium citrate-Carnoy's fixation-Giemsa staining procedures of the hematopoitetic cells in the anterior kidneys revealed that the diploid chromosome number was 2n=46 (46A. Fundamental Number (FN is also 46, since all chromosomal morphology were acrocentrics without any distinguishable heteromorphic pair of chromosomes in the metaphase spreads from both dry and wet preparations. This study confirms previous reports on the chromosomal sets of G. giuris from India.

  9. Simplifying dynamic river water quality modelling: A case study of inorganic nitrogen dynamics in the Crocodile River (South Africa).

    CSIR Research Space (South Africa)

    Deksissa, T

    2004-06-01

    Full Text Available and river water quality in the future. A simplified river water quality model was formulated based on a conceptual hydraulic sub-model and simplification of an existing river water quality model. The simplified water quality was derived from the River Water...

  10. Prediction and setup of phytoplankton statistical model of Qiandaohu Lake

    Institute of Scientific and Technical Information of China (English)

    严力蛟; 全为民; 赵晓慧

    2004-01-01

    This research considers the mathematical relationship between concentration of Chla and seven environmental factors, i.e. Lake water temperature (T), Secci-depth (SD), pH, DO, CODMn, Total Nitrogen (TN), Total Phosphorus (TP).Stepwise linear regression of 1997 to 1999 monitoring data at each sampling point of Qiandaohu Lake yielded the multivariate regression models presented in this paper. The concentration of Chla as simulation for the year 2000 by the regression model was similar to the observed value. The suggested mathematical relationship could be used to predict changes in the lakewater environment at any point in time. The results showed that SD, TP and pH were the most significant factors affecting Chla concentration.

  11. Public Lakes, Private Lakeshore: Modeling Protection of Native Aquatic Plants

    Science.gov (United States)

    Schroeder, Susan A.; Fulton, David C.

    2013-07-01

    Protection of native aquatic plants is an important proenvironmental behavior, because plant loss coupled with nutrient loading can produce changes in lake ecosystems. Removal of aquatic plants by lakeshore property owners is a diffuse behavior that may lead to cumulative impacts on lake ecosystems. This class of behavior is challenging to manage because collective impacts are not obvious to the actors. This paper distinguishes positive and negative beliefs about aquatic plants, in models derived from norm activation theory (Schwartz, Adv Exp Soc Psychol 10:221-279, 1977) and the theory of reasoned action (Fishbein and Ajzen, Belief, attitude, intention, and behavior: an introduction to theory and research, Addison-Wesley, Boston 1975), to examine protection of native aquatic plants by Minnesota lakeshore property owners. We clarify how positive and negative evaluations of native aquatic plants affect protection or removal of these plants. Results are based on a mail survey ( n = 3,115). Results suggest that positive evaluations of aquatic plants (i.e., as valuable to lake ecology) may not connect with the global attitudes and behavioral intentions that direct plant protection or removal. Lakeshore property owners' behavior related to aquatic plants may be driven more by tangible personal benefits derived from accessible, carefully managed lakeshore than intentional action taken to sustain lake ecosystems. The limited connection of positive evaluations of aquatic plants to global attitudes and behavioral intentions may reflect either lack of knowledge of what actions are needed to protect lake health and/or unwillingness to lose perceived benefits derived from lakeshore property.

  12. Public lakes, private lakeshore: modeling protection of native aquatic plants.

    Science.gov (United States)

    Schroeder, Susan A; Fulton, David C

    2013-07-01

    Protection of native aquatic plants is an important proenvironmental behavior, because plant loss coupled with nutrient loading can produce changes in lake ecosystems. Removal of aquatic plants by lakeshore property owners is a diffuse behavior that may lead to cumulative impacts on lake ecosystems. This class of behavior is challenging to manage because collective impacts are not obvious to the actors. This paper distinguishes positive and negative beliefs about aquatic plants, in models derived from norm activation theory (Schwartz, Adv Exp Soc Psychol 10:221-279, 1977) and the theory of reasoned action (Fishbein and Ajzen, Belief, attitude, intention, and behavior: an introduction to theory and research, Addison-Wesley, Boston 1975), to examine protection of native aquatic plants by Minnesota lakeshore property owners. We clarify how positive and negative evaluations of native aquatic plants affect protection or removal of these plants. Results are based on a mail survey (n = 3,115). Results suggest that positive evaluations of aquatic plants (i.e., as valuable to lake ecology) may not connect with the global attitudes and behavioral intentions that direct plant protection or removal. Lakeshore property owners' behavior related to aquatic plants may be driven more by tangible personal benefits derived from accessible, carefully managed lakeshore than intentional action taken to sustain lake ecosystems. The limited connection of positive evaluations of aquatic plants to global attitudes and behavioral intentions may reflect either lack of knowledge of what actions are needed to protect lake health and/or unwillingness to lose perceived benefits derived from lakeshore property.

  13. Developing Flexible, Integrated Hydrologic Modeling Systems for Multiscale Analysis in the Midwest and Great Lakes Region

    Science.gov (United States)

    Hamlet, A. F.; Chiu, C. M.; Sharma, A.; Byun, K.; Hanson, Z.

    2016-12-01

    Physically based hydrologic modeling of surface and groundwater resources that can be flexibly and efficiently applied to support water resources policy/planning/management decisions at a wide range of spatial and temporal scales are greatly needed in the Midwest, where stakeholder access to such tools is currently a fundamental barrier to basic climate change assessment and adaptation efforts, and also the co-production of useful products to support detailed decision making. Based on earlier pilot studies in the Pacific Northwest Region, we are currently assembling a suite of end-to-end tools and resources to support various kinds of water resources planning and management applications across the region. One of the key aspects of these integrated tools is that the user community can access gridded products at any point along the end-to-end chain of models, looking backwards in time about 100 years (1915-2015), and forwards in time about 85 years using CMIP5 climate model projections. The integrated model is composed of historical and projected future meteorological data based on station observations and statistical and dynamically downscaled climate model output respectively. These gridded meteorological data sets serve as forcing data for the macro-scale VIC hydrologic model implemented over the Midwest at 1/16 degree resolution. High-resolution climate model (4km WRF) output provides inputs for the analyses of urban impacts, hydrologic extremes, agricultural impacts, and impacts to the Great Lakes. Groundwater recharge estimated by the surface water model provides input data for fine-scale and macro-scale groundwater models needed for specific applications. To highlight the multi-scale use of the integrated models in support of co-production of scientific information for decision making, we briefly describe three current case studies addressing different spatial scales of analysis: 1) Effects of climate change on the water balance of the Great Lakes, 2) Future

  14. Evaluation of the Siltation of River Taquari, Pantanal, Brazil, through 210Pb Geochronology of Floodplain Lake Sediments

    Directory of Open Access Journals (Sweden)

    Godoy José M.

    2002-01-01

    Full Text Available This work presents the 210Pb geochronology of seven bottom sediment cores, collected in three floodplain lakes located in the area of the middle Taquari River, Pantanal, Brazil. In five of them, a significant increase in the sediment mass deposition rate was observed, reflecting an increase of the sediment input to the Pantanal. Additionally, in order to validate the 210Pb results, the mercury content was determined for two sediment cores, showing that despite a constant concentration, the flux of Hg has increased due to an increase in the mass sedimentation rate. This increase can be attributed to the expansion of agricultural activity in the upper Taquari River during the last 25 years.

  15. Stochastic Downscaling for Hydrodynamic and Ecological Modeling of Lakes

    Science.gov (United States)

    Schlabing, D.; Eder, M.; Frassl, M.; Rinke, K.; Bárdossy, A.

    2012-04-01

    Weather generators are of interest in climate impact studies, because they allow different modi operandi: (1) More realizations of the past, (2) possible futures as defined by the modeler and (3) possible futures according to the combination of greenhouse gas emission scenarios and their Global Circulation Model (GCM) consequences. Climate modeling has huge inherently unquantifiable uncertainties, yet the results present themselves as single point values without any measure of uncertainty. Given this reduction of risk-relevant information, stochastic downscaling offers itself as a tool to recover the variability present in local measurements. One should bear in mind that the lake models that are fed with downscaling results are themselves deterministic and single runs may prove to be misleading. Especially population dynamics simulated by ecological models are sensitive to very particular events in the input data. A way to handle this sensitivity is to perform Monte Carlo studies with varying meteorological driving forces using a weather generator. For these studies, the Vector-Autoregressive Weather generator (VG), which was first presented at the EGU 2011, was developed further. VG generates daily air temperature, humidity, long- and shortwave radiance and wind. Wind and shortwave radiation is subsequently disaggregated to hourly values, because their short term variability has proven important for the application. Changes relative to the long-term values are modeled as disturbances that act during the autoregressive generation of the synthetic time series. The method preserves the dependence structure between the variables, as changes in the disturbed variable, say temperature, are propagated to the other variables. The approach is flexible because the disturbances can be chosen freely. Changes in mean can be represented as constant disturbance, changes in variability as episodes of certain length and amplitude. The disturbances can also be extracted from GCMs

  16. Travel times, streamflow velocities, and dispersion rates in the Missouri River upstream from Canyon Ferry Lake, Montana

    Science.gov (United States)

    Whiteman, Aroscott

    2012-01-01

    In 2010, the U.S. Geological Survey, in cooperation with the Montana Department of Environmental Quality, initiated a dye-tracer study to determine travel times, streamflow velocities, and longitudinal dispersion rates for the Missouri River upstream from Canyon Ferry Lake. For this study, rhodamine WT (RWT) dye was injected at two locations, Missouri River Headwaters State Park in early September and Broadwater-Missouri Dam (Broadwater Dam) in late August 2010. Dye concentrations were measured at three sites downstream from each dye-injection location. The study area was a 41.2-mile reach of the Missouri River from Trident, Montana, at the confluence of the Jefferson, Madison, and Gallatin Rivers (Missouri River Headwaters) at river mile 2,319.40 downstream to the U.S. Route 12 Bridge (Townsend Bridge), river mile 2,278.23, near Townsend, Montana. Streamflows were reasonably steady and ranged from 3,070 to 3,700 cubic feet per second. Mean velocities were calculated for each subreach between measurement sites for the leading edge, peak concentration, centroid, and trailing edge at 10 percent of the peak concentration of the dye plume. Calculated velocities for the centroid of the dye plume ranged from 0.80 to 3.02 feet per second within the study reach from Missouri River Headwaters to Townsend Bridge, near Townsend. The mean velocity of the dye plume for the entire study reach, excluding the subreach between the abandoned Milwaukee Railroad bridge at Lombard, Montana (Milwaukee Bridge) and Broadwater-Missouri Dam (Broadwater Dam), was 2.87 feet per second. The velocity of the centroid of the dye plume for the subreach between Milwaukee Bridge and Broadwater Dam (Toston Reservoir) was 0.80 feet per second. The residence time for Toston Reservoir was 8.2 hours during this study. Estimated longitudinal dispersion rates of the dye plume for this study ranged from 0.72 feet per second for the subreach from Milwaukee Bridge to Broadwater Dam to 2.26 feet per second for

  17. Modeling CO2 air dispersion from gas driven lake eruptions

    Science.gov (United States)

    Chiodini, Giovanni; Costa, Antonio; Rouwet, Dmitri; Tassi, Franco

    2016-04-01

    The most tragic event of gas driven lake eruption occurred at Lake Nyos (Cameroon) on 21 August 1986, when a dense cloud of CO2 suffocated more than 1700 people and an uncounted number of animals in just one night. The event stimulated a series of researches aimed to understand gas origins, gas release mechanisms and strategies for gas hazard mitigation. Very few studies have been carried out for describing the transport of dense CO2 clouds in the atmosphere. Although from a theoretical point of view, gas dispersion can be fully studied by solving the complete equations system for mass, momentum and energy transport, in actual practice, different simplified models able to describe only specific phases or aspects have to be used. In order to simulate dispersion of a heavy gas and to assess the consequent hazard we used a model based on a shallow layer approach (TWODEE2). This technique which uses depth-averaged variables to describe the flow behavior of dense gas over complex topography represents a good compromise between the complexity of computational fluid dynamic models and the simpler integral models. Recently the model has been applied for simulating CO2 dispersion from natural gas emissions in Central Italy. The results have shown how the dispersion pattern is strongly affected by the intensity of gas release, the topography and the ambient wind speed. Here for the first time we applied TWODEE2 code to simulate the dispersion of the large CO2 clouds released by limnic eruptions. An application concerns the case of the 1986 event at lake Nyos. Some difficulties for the simulations were related to the lack of quantitative information: gas flux estimations are not well constrained, meteorological conditions are only qualitatively known, the digital model of the terrain is of poor quality. Different scenarios were taken into account in order to reproduce the qualitative observations available for such episode. The observations regard mainly the effects of gas on

  18. Map of Western Copper River Basin, Alaska, Showing Lake Sediments and Shorelines, Glacial Moraines, and Location of Stratigraphic Sections and Radiocarbon-Dated Samples

    Science.gov (United States)

    Williams, John R.; Galloway, John P.

    1986-01-01

    The purpose of this report is to make available basic data on radiocarbon dating of 61 organic samples from 40 locations in the western Copper River Basin and adjacent uplands and in the uppermost Matanuska River Valley. The former distribution of late Quaternary glacial lakes and of glaciers as mapped from field work and photo interpretation is provided as background for interpretation of the radiocarbon dates and are the basic data needed for construction of the late Quaternary chronology. The glacial boundaries, formed and expressed by moraines, ice-contact margins, marginal channels, deltas, and other features, are obscured by a drape of glaciolacustrine deposits in a series of glacial lakes. The highest lake, represented by bottom sediments as high as 914 m to 975 m above sea level, extends from Fog Lakes lowland on Susitna River upstream into the northwestern part of the Copper River Basin (the part now draining to Susitna River) where it apparently was held in by an ice border. It was apparently dammed by ice from the Mt. McKinley area, by Talkeetna G1acier, and may have had a temporary drainage threshold at the headwaters of Chunilna Creek. No shorelines have been noted within the map area, although Nichols and Yehle (1961) reported shorelines within the 914-975 m range in the Denali area to the north of that mapped. Recent work by geologic consultants for the Susitna Hydroelectric Project has confirmed the early inferences (Karlstrom, 1964) about the existence of a lake in the Susitna canyon, based originally on drilling by the Bureau of Reclamation about 35 years ago. According to dating of deposits at Tyone Bluff (map locations 0, P), Thorson and others (1981) concluded that a late Wisconsin advance of the glaciers between 11,535 and 21,730 years ago was followed by a brief interval of lacustrine sedimentation, and was preceded by a long period of lake deposition broken by a lowering of the lake between 32,000 and about 25,000 years ago. An alternate

  19. Spawning site fidelity and apparent annual survival of walleye (Sander vitreus) differ between a Lake Huron and Lake Erie tributary

    Science.gov (United States)

    Hayden, Todd A.; Binder, Thomas; Holbrook, Christopher; Vandergoot, Christopher; Fielder, David G.; Cooke, Steven J.; Dettmers, John M; Krueger, Charles Conrad

    2017-01-01

    Fidelity to spawning habitats can maximise reproductive success of fish by synchronising movements to sites of previous recruitment. To determine the role of reproductive fidelity in structuring walleye Sander vitreus populations in the Laurentian Great Lakes, we used acoustic telemetry combined with Cormack–Jolly–Seber capture–recapture models to estimate spawning site fidelity and apparent annual survival for the Tittabawassee River in Lake Huron and Maumee River in Lake Erie. Walleye in spawning condition were tagged from the Tittabawassee River in Lake Huron and Maumee River in Lake Erie in 2011–2012. Site fidelity and apparent annual survival were estimated from return of individuals to the stream where tagged. Site fidelity estimates were higher in the Tittabawassee River (95%) than the Maumee River (70%) and were not related to sex or fish length at tagging. Apparent annual survival of walleye tagged in the Tittabawassee did not differ among spawning seasons but was higher for female than male walleye and decreased linearly as fish length increased. Apparent annual survival of walleye tagged in the Maumee River did not differ among spawning seasons but was higher for female walleye than male walleye and increased linearly as fish length increased. Greater fidelity of walleye tagged in the Tittabawassee River than walleye tagged in the Maumee River may be related to the close proximity to the Maumee River of other spawning aggregations and multiple spawning sites in Lake Erie. As spawning site fidelity increases, management actions to conserve population structure require an increasing focus on individual stocks.

  20. Technical Note: Automatic river network generation for a physically-based river catchment model

    Directory of Open Access Journals (Sweden)

    S. J. Birkinshaw

    2010-09-01

    Full Text Available SHETRAN is a physically-based distributed modelling system that gives detailed simulations in time and space of water flow and sediment and solute transport in river catchments. Standard algorithms for the automatic generation of river channel networks from digital elevation data are impossible to apply in SHETRAN and other similar models because the river channels are assumed to run along the edges of grid cells. In this work a new algorithm for the automatic generation of a river channel network in SHETRAN is described and its use in an example catchment demonstrated.

  1. Technical Note: Automatic river network generation for a physically-based river catchment model

    Science.gov (United States)

    Birkinshaw, S. J.

    2010-09-01

    SHETRAN is a physically-based distributed modelling system that gives detailed simulations in time and space of water flow and sediment and solute transport in river catchments. Standard algorithms for the automatic generation of river channel networks from digital elevation data are impossible to apply in SHETRAN and other similar models because the river channels are assumed to run along the edges of grid cells. In this work a new algorithm for the automatic generation of a river channel network in SHETRAN is described and its use in an example catchment demonstrated.

  2. Technical Note: Automatic river network generation for a physically-based river catchment model

    Directory of Open Access Journals (Sweden)

    S. J. Birkinshaw

    2010-05-01

    Full Text Available SHETRAN is a physically-based distributed modelling system that gives detailed simulations in time and space of water flow and sediment and solute transport in river catchments. Standard algorithms for the automatic generation of river channel networks from digital elevation data are impossible to apply in SHETRAN and other similar models because the river channels are assumed to run along the edges of grid cells. In this work a new algorithm for the automatic generation of a river channel network in SHETRAN is described and its use in an example catchment demonstrated.

  3. Audubon National Wildlife Refuge, Lake Nettie National Wildlife Refuge, Camp-Strawberry Lake Easement Refuge, Cottonwood Lake Easement Refuge, Wintering River Easement Refuge, Sheyenne Lake Easement Refuge : Narrative report : 1968

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Audubon National Wildlife Refuge (including Lake Nettie National Wildlife Refuge, Camp-Strawberry Lake Easement Refuge, Cottonwood...

  4. Sedimentation and Occurrence and Trends of Selected Nutrients, Other Chemical Constituents, and Diatoms in Bottom Sediment, Fall River Lake, Southeast Kansas, 1948-2006

    Science.gov (United States)

    Juracek, Kyle E.

    2008-01-01

    A combination of available bathymetric-survey information and bottom-sediment coring was used to investigate sedimentation and the occurrence of selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, diatoms, and the radionuclide cesium-137 in the bottom sediment of Fall River Lake, southeast Kansas. The total estimated volume and mass of bottom sediment deposited from 1948 through 2006 in the original conservation pool of the reservoir was 470 million cubic feet and 18.8 billion pounds, respectively. The estimated sediment volume occupied about 36 percent of the original conservation-pool, water-storage capacity of the reservoir. Mean annual net sediment deposition since 1948 in the original conservation pool of the reservoir was estimated to be 324 million pounds per year. Mean annual net sediment yield from the Fall River Lake Basin was estimated to be 585,000 pounds per square mile per year. The mean annual net loads of total nitrogen and total phosphorus deposited in the bottom sediment of Fall River Lake were estimated to be 648,000 pounds per year and 267,000 pounds per year, respectively. The estimated mean annual net yields of total nitrogen and total phosphorus from the Fall River Lake Basin were 1,170 pounds per square mile per year and 480 pounds per square mile per year, respectively. Throughout the history of Fall River Lake, total nitrogen and total phosphorus concentrations in the deposited sediment were relatively uniform. Trace element concentrations in the bottom sediment of Fall River Lake generally were uniform over time. Arsenic, chromium, nickel, and zinc concentrations typically exceeded the threshold-effects guidelines, which represent the concentrations above which toxic biological effects occasionally occur. Trace element concentrations did not exceed the probable-effects guidelines (available for eight trace elements), which represent the concentrations above which toxic biological effects

  5. Lehigh River Basin, Trexler Lake, Jordan Creek, Pennsylvania. Final Environmental Impact Statement.

    Science.gov (United States)

    1973-01-01

    adjacent to thi Trexler Lake area are musk thistle , heard tongue, butterfly weed, and arrmowood. Some of t4xe area’s other wildflowers such as trailing...septic tank contents removed, disenfected and filled. Nutrient source control and identification in the upstream feeder streams of the lake are

  6. 33 CFR 208.34 - Norman Dam and Lake Thunderbird, Little River, Okla.

    Science.gov (United States)

    2010-07-01

    ... OF THE ARMY, DEPARTMENT OF DEFENSE FLOOD CONTROL REGULATIONS § 208.34 Norman Dam and Lake Thunderbird... Thunderbird in the interest of flood control as follows: (a) Flood control storage in Lake Thunderbird between elevation 1039 (top of the conservation pool) and elevation 1049.4 (top of flood control pool)...

  7. 33 CFR 208.32 - Sanford Dam and Lake Meredith, Canadian River, Tex.

    Science.gov (United States)

    2010-07-01

    ... OF THE ARMY, DEPARTMENT OF DEFENSE FLOOD CONTROL REGULATIONS § 208.32 Sanford Dam and Lake Meredith... Lake Meredith in the interest of flood control as follows: (a) Flood control storage in the reservoir... elevation range, the flood control discharge facilities shall be operated under the direction of...

  8. Gorkha earthquake-induced landslides and dammed lakes: Evolution and outburst modeling

    Science.gov (United States)

    Shugar, D. H.; Immerzeel, W.; Wanders, N.; Kargel, J. S.; Leonard, G. J.; Haritashya, U. K.; Collins, B. D.

    2015-12-01

    On 25 April 2015, the Gorkha Earthquake (Mw 7.8) struck Nepal, generating thousands of landslides in Nepal, Tibet (China), and India. While the majority of these hazards were triggered co-seismically, many are considered secondary effects occurring during the weeks following the main shock, based on high-resolution WorldView satellite imagery. Here we report on a series of shallow, post-seismic landslides into the upper Marsyangdi River in the Annapurna region of the central Nepal Himalayas. These landslides constricted and blocked the river, causing impoundments that presented acute flood risks to communities downstream. On April 27, two days following the main shock, ~4.7 x 104 m3 of water was impounded behind a series of small constrictions. By May 28, the total volume of impounded water had increased to ~6.4 x 105 m3. The downstream flood risk was especially significant in the event of a domino-like cascade of dam breaches. We examine the timing, distribution and evolution of the landslide-dammed lakes and quantify the risk of inundation-scenarios to downstream communities with a hydrological model. The model uses a fully kinematic wave simulation at a 30 m-spatial and 2 sec-temporal resolution to resolve the height, timing and volume of a possible outburst flood wave. Our modeling shows that a rapid dam burst involving only the lowest, largest lake would increase water levels at the nearest village of Lower Pisang ~2 km downstream by >7m in a matter of minutes. Approximately 70 km downstream, the flood wave would be mostly attenuated, raising water levels only tens of centimeters. Fortunately, at the time of writing, no flood had occurred.

  9. Irrigation system and land use effect on surface water quality in river, at lake Dianchi, Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    Takashi Tanaka; Takahiro Sato; Kazuo Watanabe; Ying Wang; Dan Yang; Hiromo Inoue; Kunzhi Li

    2013-01-01

    The surface water samples were collected in river Dahe and its tributaries,which flow into severely eutrophic lake Dianchi,Yunnan Province,China,in order to elucidate factors controlling water quality fluctuations.The temporal and spatial distribution of water quality tendency was observed.The water quality of each river is dependent on the hydrology effect such water gate and circulating irrigation system.We must consider the hydrology effect to accurately understand water quality variations of river in this study field.In river without highly circulating irrigation system or water gate effect,the downstream nitrate nitrogen (NO3-N) concentration increase occurred in area dominated by open field cultivation,whereas the NO3-N concentration was constant or decreased in area dominated by greenhouse land use.This result suggests that greenhouse covers the soil from precipitation,and nitrate load of greenhouse could be less than that of open field cultivation while the rainfall event.In the upper reaches of river,where is dominated by open field cultivation,there were no sharp increase dissolved molybdate reactive phosphorus and total phosphorus concentration,but P load was accumulated in the lower reaches of river,whose predominant land use is greenhouse.Although the P sources is unclear in this study,greenhouse area may have potential of P loads due to its high P content in greenhouse soil.Considering hydrology effect is necessary to determine what the major factor is influencing the water quality variation,especially in area with highly complicated irrigation system in this studying site.

  10. Hydrological and hydraulic modelling of the Nyl River floodplain Part ...

    African Journals Online (AJOL)

    2007-01-01

    Jan 1, 2007 ... Keywords: Nyl River floodplain, Nylsvlei, Nylsvley Nature Reserve, modelling wetland hydraulics, wetland evapotranspiration ..... A review of suitable methods for estimating evapotranspira- ..... ingum routing. J. Hydrol.

  11. MODELING SIMULATION OF SEDIMENT ANALYSIS FOR MALAPRABHA RIVER IN KARNATAKA STATE, INDIA

    Directory of Open Access Journals (Sweden)

    Vinayak Krishnamurty Naik

    2008-01-01

    Full Text Available Transport, settling and quantity of solutes in rivers, streams, lakes and reservoirs are the important aspects in water-quality modeling. This has been the major concern for the researchers, scientists and engineers for the last 50 years who actively involved in water quality modeling. Consequently, characterization of hydrodynamics and water budgets has been an essential component in the water-quality modeling. This paper presents on the simulation model for sediment transport, solids budget, bottom sediment as a distributed system under steady-state condition, and resuspension of solids due to currents etc. The solids considered for the study was mainly allochthonous as these are inorganic in nature and the rate of decomposition is negligible. The data collected refers to the part of the research work on Malaprabha River, near Belgaum - a district headquarters in the State of Karnataka, India. This river is a non-perennial one, and the flow is very less during the pre-monsoon period, which is favorable for application of these sediment models. The results obtained for the resuspension and burial velocities showed marked variations during the different seasons of the year. Resuspension velocities predominated during the monsoon period resulting in the nonsettlement of the solids and the burial velocity during the non-monsoon period. As the river receives raw sewage from an adjoining town - Khanapur, and also the agricultural discharges, it is worth to quantify the sediment deposition in the stream.

  12. MODELING SIMULATION OF SEDIMENT ANALYSIS FOR MALAPRABHA RIVER IN KARNATAKA STATE, INDIA

    Directory of Open Access Journals (Sweden)

    Vinayak Krishnamurty Naik

    2008-06-01

    Full Text Available Transport, settling and quantity of solutes in rivers, streams, lakes and reservoirs are the important aspects in water-quality modeling. This has been the major concern for the researchers, scientists and engineers for the last 50 years who actively involved in water quality modeling. Consequently, characterization of hydrodynamics and water budgets has been an essential component in the water–quality modeling. This paper presents on the simulation model for sediment transport, solids budget, bottom sediment as a distributed system under steady-state condition, and resuspension of solids due to currents etc. The solids considered for the study was mainly allochthonous as these are inorganic in nature and the rate of decomposition is negligible. The data collected refers to the part of the research work on Malaprabha River, near Belgaum – a district headquarters in the State of Karnataka, India. This river is a non-perennial one, and the flow is very less during the pre-monsoon period, which is favorable for application of these sediment models. The results obtained for the resuspension and burial velocities showed marked variations during the different seasons of the year. Resuspension velocities predominated during the monsoon period resulting in the nonsettlement of the solids and the burial velocity during the non-monsoon period. As the river receives raw sewage from an adjoining town – Khanapur, and also the agricultural discharges, it is worth to quantify the sediment deposition in the stream.

  13. Demographics and run timing of adult Lost River (Deltistes luxatus) and short nose (Chasmistes brevirostris) suckers in Upper Klamath Lake, Oregon, 2012

    Science.gov (United States)

    Hewitt, David A.; Janney, Eric C.; Hayes, Brian S.; Harris, Alta C.

    2014-01-01

    Data from a long-term capture-recapture program were used to assess the status and dynamics of populations of two long-lived, federally endangered catostomids in Upper Klamath Lake, Oregon. Lost River suckers (Deltistes luxatus) and shortnose suckers (Chasmistes brevirostris) have been captured and tagged with passive integrated transponder (PIT) tags during their spawning migrations in each year since 1995. In addition, beginning in 2005, individuals that had been previously PIT-tagged were re-encountered on remote underwater antennas deployed throughout sucker spawning areas. Captures and remote encounters during spring 2012 were used to describe the spawning migrations in that year and also were incorporated into capture-recapture analyses of population dynamics. Cormack-Jolly-Seber (CJS) open population capture-recapture models were used to estimate annual survival probabilities, and a reverse-time analog of the CJS model was used to estimate recruitment of new individuals into the spawning populations. In addition, data on the size composition of captured fish were examined to provide corroborating evidence of recruitment. Model estimates of survival and recruitment were used to derive estimates of changes in population size over time and to determine the status of the populations in 2011. Separate analyses were conducted for each species and also for each subpopulation of Lost River suckers (LRS). Shortnose suckers (SNS) and one subpopulation of LRS migrate into tributary rivers to spawn, whereas the other LRS subpopulation spawns at groundwater upwelling areas along the eastern shoreline of the lake. In 2012, we captured, tagged, and released 749 LRS at four lakeshore spawning areas and recaptured an additional 969 individuals that had been tagged in previous years. Across all four areas, the remote antennas detected 6,578 individual LRS during the spawning season. Spawning activity peaked in April and most individuals were encountered at Cinder Flats and

  14. Hydrodynamic Modeling on Suciu River (Maramures County

    Directory of Open Access Journals (Sweden)

    Năsui Daniel

    2016-06-01

    Full Text Available The GIS database containing the topographic and land use information was made in 2012, followed by field measurements surveys in 2013 and 2014. A number of 11 cross-sections were topographically apprised in the valley along the 11 km river reach. The geometric data requirements for the modeling software were prepared in ESRI’s ArcGIS™ 9.2 software using the HEC-GeoRAS extension. The steady flow data was edited in the HEC-RAS one-dimensional flow modeling software. Four scenarios were used for the river discharge, from normal to overflow. The results come in different forms, from tabular output, to stage hydrograph, to velocity distribution or 3D diagrams, all of which give a clear vision on the overflow high risk areas. The results were exported back to the GIS extension for additional spatial operations. Flow velocity maps were generated for each discharge scenario. Although the scenarios included very high discharge values, the flood impact on people assets is minimal. The reasons for this are the high slope of the riverbed and the proper placement in the floodplain, due mainly to the flood management works that took place after the 1970 flood.

  15. RiverML: Standardizing the Communication of River Model Data (Invited)

    Science.gov (United States)

    Jackson, S.; Maidment, D. R.; Arctur, D. K.

    2013-12-01

    RiverML is a proposed language for conveying a description of river channel and floodplain geometry and flow characteristics through the internet in a standardized way. A key goal of the RiverML project is to allow interoperability between all hydraulic and hydrologic models, whether they are industry standard software packages or custom-built research tools. By providing a common transfer format for common model inputs and outputs, RiverML can shorten the development time and enhance the immediate utility of innovative river modeling tools. RiverML will provide descriptions of cross sections and multiple flow lines, allowing the construction of wireframe representations. In addition, RiverML will support descriptions of network connectivity, properties such as roughness coefficients, and time series observations such as water surface elevation and flow rate. The language is constructed in a modular fashion such that the geometry information, network information, and time series observations can be communicated independently of each other, allowing an arbitrary suite of software packages to contribute to a coherently modeled scenario. Funding for the development of RiverML is provided through an NSF grant to CUAHSI HydroShare project, a web-based collaborative environment for sharing data & models. While RiverML is geared toward the transfer of data, HydroShare will serve as a repository for storing water-related data and models of any format, while providing enhanced functionality for standardized formats such as RiverML, WaterML, and shapefiles. RiverML is a joint effort between the CUAHSI HydroShare development team, the Open Geospatial Consortium (OGC) Hydrology Domain Working Group, and an international community of data providers, data users, and software developers.

  16. Mercury trends in fish from rivers and lakes in the United States, 1969-2005

    Science.gov (United States)

    Chalmers, A.T.; Argue, D.M.; Gay, D.A.; Brigham, M.E.; Schmitt, C.J.; Lorenz, D.L.

    2011-01-01

    A national dataset on concentrations of mercury in fish, compiled mainly from state and federal monitoring programs, was used to evaluate trends in mercury (Hg) in fish from US rivers and lakes. Trends were analyzed on data aggregated by site and by state, using samples of the same fish species and tissue type, and using fish of similar lengths. Site-based trends were evaluated from 1969 to 2005, but focused on a subset of the data from 1969 to 1987. Data aggregated by state were used to evaluate trends in fish Hg concentrations from 1988 to 2005. In addition, the most recent Hg fish data (1996-2005) were compared to wet Hg deposition data from the Mercury Deposition Network (MDN) over the same period. Downward trends in Hg concentrations in fish from data collected during 1969-1987 exceeded upward trends by a ratio of 6 to 1. Declining Hg accumulation rates in sediment and peat cores reported by many studies during the 1970s and 1980s correspond with the period when the most downward trends in fish Hg concentrations occurred. Downward Hg trends in both sediment cores and fish were also consistent with the implementation of stricter regulatory controls of direct releases of Hg to the atmosphere and surface waters during the same period. The southeastern USA had more upward Hg trends in fish than other regions for both site and state aggregated data. Upward Hg trends in fish from the southeastern USA were associated with increases in wet deposition in the region and may be attributed to a greater influence of global atmospheric Hg emissions in the southeastern USA. No significant trends were found in 62% of the fish species from six states from 1996 to 2005. A lack of Hg trends in fish in the more recent data was consistent with the lack of trends in wet Hg deposition at MDN sites and with relatively constant global emissions during the same time period. Although few significant trends were observed in the more recent Hg concentrations in fish, it is anticipated

  17. Review of potential interactions between stocked rainbow trout and listed Snake River sockeye salmon in Pettit Lake Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Teuscher, D.

    1996-05-01

    The objective of this study was to determine if hatchery rainbow trout compete with or prey on juvenile Snake River sockeye salmon Oncorhynchus nerka in Pettit Lake, Idaho. In 1995, a total of 8,570 age-0 sockeye and 4,000 hatchery rainbow trout were released in Pettit Lake. After releasing the fish, gillnets were set in the pelagic and littoral zones to collected diet and spatial distribution data. Interactions were assessed monthly from June 1995 through March 1996. Competition for food was discounted based on extremely low diet overlap results observed throughout the sample period. Conversely, predation interactions were more significant. A total of 119 rainbow trout stomachs were analyzed, two contained O. nerka. The predation was limited to one sample period, but when extrapolated to the whole rainbow trout populations results in significant losses. Total consumption of O. nerka by rainbow trout ranged from an estimated 10 to 23% of initial stocking numbers. Predation results contradict earlier findings that stocked rainbow trout do not prey on wild kokanee or sockeye in the Sawtooth Lakes. The contradiction may be explained by a combination of poorly adapted hatchery sockeye and a littoral release site that forced spatial overlap that was not occurring in the wild populations. Releasing sockeye in the pelagic zone may have reduced or eliminated predation losses to rainbow trout.

  18. Arsenopyrite in the bank deposits of the Whitewood Creek-Belle Fourche-Cheyenne River-Lake Oahe system, South Dakota, U.S.A.

    Science.gov (United States)

    Horowitz, A.J.; Elrick, K.A.; Cook, R.B.

    1990-01-01

    Mining, milling, and processing wastes containing quantities of arsenopyrite were produced around Lead, South Dokata, from 1875 to 1977. Much of this material was discharged into Whitewood Creek, and from there portions of the waste were transported to the Belle Fourche River, thence to the Cheyenne River, and finally to the Missouri River. In 1958, the Missouri River was dammed at Pierre, forming Lake Oahe. Analyses of cores collected from the lake bottom showed the presence of arsenic-rich layers in the bed sediments; substantial portions of the arsenic are due to arsenopyrite in the 8-16 and 16-32 ??m size fractions of the sediments. In addition, suspended-sediment samples collected from the Cheyenne River above Lake Oahe contain detectable quantities of arsenopyrite in the 8-16 and 16-32 ??m fractions. Solid material collected from the banks and floodplains of the Belle Fourche River and Whitewood Creek contains reduced and oxidized phases. The reduced phases have arsenic maxima in the 16-32 and 32-63 ??m size ranges. These fractions also contribute the most arsenic to the samples; the major source being arsenopyrite. The oxidized segments have arsenic maxima in the 63 ??m size ranges. The 63 ??m fractions contribute the most arsenic to the oxidized samples. This arsenic, despite the oxidized nature of the samples, is associated with arsenopyrite coated with thin iron oxide rinds. It has been calculated that 80% of the arsenic in these deposits is associated with sulfides (in the form of arsenopyrite), while 20% is associated with iron oxides. The arsenopyrite found in the banks and floodplains of Whitewood Creek and the Belle Fourche River are the likely source of the arsenopyrite found in the suspended sediments of the Cheyenne River and in the bed sediment of Lake Oahe.

  19. A model of the sediment transport on a river network

    Science.gov (United States)

    Wang, Xu-Ming; Hao, Rui; Zhang, Jin-Feng; Huo, Jie

    2007-03-01

    A dynamical model is proposed to mimic the sediment transport on a river network. A river can be divided into some segments. For the ith segment the schlepping sediment ability of the flow may be scouring or depositing, which is influenced by that of the (i- 1)th segment. In order to compare our model simulation results with the empirical data obtained in Yellow River, the model is equipped with an experiential relation between the flow rate and the depositing rate of the Yellow River. After this, the simulation results show an excellent agreement with the empirical conclusions obtained with the upper and middle parts of Yellow River when it is in the low-water periods (for instance, in Dec., Jan. and Feb.). This indicates that our model may successfully describe the scouring-depositing of river networks.

  20. Status and trends of adult Lost River (Deltistes luxatus) and shortnose (Chasmistes brevirostris) sucker populations in Upper Klamath Lake, Oregon, 2015

    Science.gov (United States)

    Hewitt, David A.; Janney, Eric C.; Hayes, Brian S.; Harris, Alta C.

    2017-07-21

    Executive SummaryData from a long-term capture-recapture program were used to assess the status and dynamics of populations of two long-lived, federally endangered catostomids in Upper Klamath Lake, Oregon. Lost River suckers (LRS; Deltistes luxatus) and shortnose suckers (SNS; Chasmistes brevirostris) have been captured and tagged with passive integrated transponder (PIT) tags during their spawning migrations in each year since 1995. In addition, beginning in 2005, individuals that had been previously PIT-tagged were re-encountered on remote underwater antennas deployed throughout sucker spawning areas. Captures and remote encounters during the spawning season in spring 2015 were incorporated into capture-recapture analyses of population dynamics. Cormack-Jolly-Seber (CJS) open population capture-recapture models were used to estimate annual survival probabilities, and a reverse-time analog of the CJS model was used to estimate recruitment of new individuals into the spawning populations. In addition, data on the size composition of captured fish were examined to provide corroborating evidence of recruitment. Separate analyses were done for each species and also for each subpopulation of LRS. Shortnose suckers and one subpopulation of LRS migrate into tributary rivers to spawn, whereas the other LRS subpopulation spawns at groundwater upwelling areas along the eastern shoreline of the lake. Characteristics of the spawning migrations in 2015, such as the effects of temperature on the timing of the migrations, were similar to past years.Capture-recapture analyses for the LRS subpopulation that spawns at the shoreline areas included encounter histories for 13,617 individuals, and analyses for the subpopulation that spawns in the rivers included 39,321 encounter histories. With a few exceptions, the survival of males and females in both subpopulations was high (greater than or equal to 0.86) between 1999 and 2013. Survival was notably lower for males from the rivers

  1. Imaging beneath the skin of large tropical rivers: System morphodynamics of the Fly and Beni Rivers revealed by novel sub-surface sonar, deep coring, and modelling

    Science.gov (United States)

    Aalto, R. E.; Grenfell, M.; Lauer, J. W.

    2011-12-01

    Tropical rivers dominate Earth's fluvial fluxes for water, carbon, and mineral sediment. They are characterized by large channels and floodplains, old system histories, prolonged periods of flooding, and a clay-dominated sediment flux. However, the underlying bed & floodplain strata are poorly understood. Available data commonly stem from skin-deep approaches such as GIS analysis of imagery, shallow sampling & topographic profiling during lower river stages. Given the large temporal & spatial scales, new approaches are needed to see below lag deposits on mobile sandy beds & deep into expansive floodbasins. Furthermore, such data are needed to test whether we can interpret large tropical river morphology using analogies to small temperate systems. Systems in a dynamic state of response to sea level rise or an increase/contrast in sediment load would provide especially valuable insight. Last August we conducted a field campaign along the Fly and Strickland Rivers in Papua New Guinea (discharge ~5,350 CMS) and this September we investigated the Beni River in Northern Bolivia (discharge ~3,500 CMS). Results were obtained using a novel measurement method: a high-power (>4kW) dual-frequency SyQwest sub-bottom profiler customized to best image 10-20m below the river/lake bed in shallow water. We were able to distinguish sandy deposits from harder clay and silt lenses and also collected bed grab samples to verify our sonar results. Deep borehole samples (5-15m), bank samples, and push cores confirmed observations from the sonar profiling. We simultaneously collected side-scan sonar imagery plus DGPS records of water/bed elevations that could be used to parameterize numerical models. We have now analyzed these results in some detail. Findings for the Fly River include: 1) The prevalence of hard clay beneath the bed of the Lower Fly River and many locations along the Strickland River, retarding migration; 2) Unusual bed morphology along the lower Middle Fly River, where the

  2. Modeling methane emissions from arctic lakes: Model development and site-level study

    Science.gov (United States)

    Tan, Zeli; Zhuang, Qianlai; Walter Anthony, Katey

    2015-06-01

    To date, methane emissions from lakes in the pan-arctic region are poorly quantified. In order to investigate the response of methane emissions from this region to global warming, a process-based climate-sensitive lake biogeochemical model was developed. The processes of methane production, oxidation, and transport were modeled within a one-dimensional sediment and water column. The sizes of 14C-enriched and 14C-depleted carbon pools were explicitly parameterized. The model was validated using observational data from five lakes located in Siberia and Alaska, representing a large variety of environmental conditions in the arctic. The model simulations agreed well with the measured water temperature and dissolved CH4 concentration (mean error less than 1°C and 0.2 μM, respectively). The modeled CH4 fluxes were consistent with observations in these lakes. We found that bubbling-rate-controlling nitrogen (N2) stripping was the most important factor in determining CH4 fraction in bubbles. Lake depth and ice cover thickness in shallow waters were also controlling factors. This study demonstrated that the thawing of Pleistocene-aged organic-rich yedoma can fuel sediment methanogenesis by supplying a large quantity of labile organic carbon. Observations and modeling results both confirmed that methane emission rate at thermokarst margins of yedoma lakes was much larger (up to 538 mg CH4 m-2 d-1) than that at nonthermokarst zones in the same lakes and a nonyedoma, nonthermokarst lake (less than 42 mg CH4 m-2 d-1). The seasonal variability of methane emissions can be explained primarily by energy input and organic carbon availability.

  3. A model for landscape development in terms of shoreline displacement, sediment dynamics, lake formation, and lake choke-up processes

    Energy Technology Data Exchange (ETDEWEB)

    Brydsten, Lars [Umeaa University, Dept. of Ecology and Environmental Science (Sweden)

    2006-12-15

    This project expands on the study 'A mathematical model for lake ontogeny in terms of filling with sediments and macrophyte vegetation' published in SKB TR-04-09. As the title suggests, this older model focuses on lakes (existing and future lakes). This newer study extends the model to examine progress of terrestrial objects such as mires or arable land. Furthermore, this newer model could simulate progress of the areas close to the objects. These areas are divided according to their watershed boundaries. If two or more objects are situated along the same brook, the lower situated area is defined as its catchments minus the catchments of the closest higher situated object. The model encourages the study of an object situated in the sea from the time of deglaciation (c. 10,000 BP) to the time for the object due to positive shore displacement is situated on land or that a lake object has progressed to a wetland, however not longer than 18,000 AP. The model focuses on the object and its location in 100-year steps. The model is written in VisualBasic and is divided into two modules, a marine module and a lake module. The marine module deals with shoreline displacement, erosion and accumulation of postglacial fine-grained sediments and erosion of glacial clay. Inputs to the marine module are a digital elevation model (DEM), a digital map showing the extension of the objects and a marine quaternary map. The two maps are in raster formats with exactly the same formats (extension and cell sizes) as the DEM. For each time step the water depths at each pixel are calculated using a shore displacement equation. Next, the water depth changes due to sediment dynamics are calculated using the following rules; accumulation of fine-grained sediments are allowed if the pixel is situated within a future lake object; erosion of fine-grained sediment is allowed if the pixel is not within a future lake object and the marine quaternary map shows occurrence of postglacial

  4. Modeling mercury biomagnification (South River, Virginia, USA) to inform river management decision making.

    Science.gov (United States)

    Tom, Kyle R; Newman, Michael C; Schmerfeld, John

    2010-04-01

    Mercury trophic transfer in the South River (VA, USA) was modeled to guide river remediation decision making. Sixteen different biota types were collected at six sites within 23 river miles. Mercury biomagnification was modeled using a general biomagnification model based on delta(15)N and distance from the historic mercury release. Methylmercury trophic transfer was clearer than that for total Hg and, therefore, was used to build the predictive model (r(2) (prediction) = 0.76). The methylmercury biomagnification factors were similar among sites, but model intercept did increase with distance down river. Minimum Akaike's Information Criterion Estimation (MAICE) justified the incorporation of distance in the model. A model with a very similar biomagnification factor to the South River (95% confidence intervals [CI] = 0.38-0.52) was produced for a second contaminated Virginia river, the North Fork Holston River (95% CI = 0.41-0.55). Percent of total Hg that was methylmercury increased monotonically with trophic position. Trophic models based on delta(15)N were adequate for predicting changes in mercury concentrations in edible fish under different remediation scenarios.

  5. Review of revised Klamath River Total Maximum Daily Load models from Link River Dam to Keno Dam, Oregon

    Science.gov (United States)

    Rounds, Stewart A.; Sullivan, Annett B.

    2013-01-01

    Flow and water-quality models are being used to support the development of Total Maximum Daily Load (TMDL) plans for the Klamath River downstream of Upper Klamath Lake (UKL) in south-central Oregon. For riverine reaches, the RMA-2 and RMA-11 models were used, whereas the CE-QUAL-W2 model was used to simulate pooled reaches. The U.S. Geological Survey (USGS) was asked to review the most upstream of these models, from Link River Dam at the outlet of UKL downstream through the first pooled reach of the Klamath River from Lake Ewauna to Keno Dam. Previous versions of these models were reviewed in 2009 by USGS. Since that time, important revisions were made to correct several problems and address other issues. This review documents an assessment of the revised models, with emphasis on the model revisions and any remaining issues. The primary focus of this review is the 19.7-mile Lake Ewauna to Keno Dam reach of the Klamath River that was simulated with the CE-QUAL-W2 model. Water spends far more time in the Lake Ewauna to Keno Dam reach than in the 1-mile Link River reach that connects UKL to the Klamath River, and most of the critical reactions affecting water quality upstream of Keno Dam occur in that pooled reach. This model review includes assessments of years 2000 and 2002 current conditions scenarios, which were used to calibrate the model, as well as a natural conditions scenario that was used as the reference condition for the TMDL and was based on the 2000 flow conditions. The natural conditions scenario included the removal of Keno Dam, restoration of the Keno reef (a shallow spot that was removed when the dam was built), removal of all point-source inputs, and derivation of upstream boundary water-quality inputs from a previously developed UKL TMDL model. This review examined the details of the models, including model algorithms, parameter values, and boundary conditions; the review did not assess the draft Klamath River TMDL or the TMDL allocations

  6. Improving assessment accuracy for lake biological condition by classifying lakes with diatom typology, varying metrics and modeling multimetric indices.

    Science.gov (United States)

    Liu, Bo; Stevenson, R Jan

    2017-12-31

    Site grouping by regions or typologies, site-specific modeling and varying metrics among site groups are four approaches that account for natural variation, which can be a major source of error in ecological assessments. Using a data set from the 2007 National Lakes Assessment project of the USEPA, we compared performances of multimetric indices (MMI) of biological condition that were developed: (1) with different lake grouping methods, ecoregions or diatom typologies; (2) by varying or not varying metrics among site groups; and (3) with different statistical techniques for modeling diatom metric values expected for minimally disturbed condition for each lake. Hierarchical modeling of MMIs, i.e. grouping sites by ecoregions or typologies and then modeling natural variability in metrics among lakes within groups, substantially improved MMI performance compared to using either ecoregions or site-specific modeling alone. Compared with MMIs based on ecoregion site groups, MMI precision and sensitivity to human disturbance were better when sites were grouped by diatom typologies and assessing performance nationwide. However, when MMI performance was evaluated at site group levels, as some government agencies often do, there was little difference in MMI performance between the two site grouping methods. Low numbers of reference and highly impacted sites in some typology groups likely limited MMI performance at the group level of analysis. Varying metrics among site groups did not improve MMI performance. Random forest models for site-specific expected metric values performed better than classification and regression tree and multiple linear regression, except when numbers of reference sites were small in site groups. Then classification and regression tree models were most precise. Based on our results, we recommend hierarchical modeling in future large scale lake assessments where lakes are grouped by ecoregions or diatom typologies and site-specific metric models are

  7. Modelling the effects of atmospheric sulphur and nitrogen deposition on selected lakes and streams of the Central Alps (Italy

    Directory of Open Access Journals (Sweden)

    M. Rogora

    2003-01-01

    Full Text Available The dynamic model MAGIC was calibrated and applied to selected sites in north-western Italy (3 rivers, 10 alpine lakes to predict the future response of surface water to different scenarios of atmospheric deposition of S and N compounds. Results at the study sites suggest that several factors other than atmospheric deposition may influence the long-term changes in surface water chemistry. At present the lumped approach of dynamic models such as MAGIC cannot represent all the processes occurring at the catchment scale. Climate warming in particular and its effects on surface water chemistry proved to be important in the study area. Furthermore the river catchments considered here showed clear signs of N saturation. This condition and the increasing concentrations of NO3 in river water were simulated using N dynamics recently included in MAGIC. The modelling performed in this study represents the first application of MAGIC to Italian sites. The results show that inclusion of other factors specific to the Mediterranean area, such as dust deposition and climate change, may improve the fit to observed data and the reliability of the model forecast. Despite these limitations, the model captured well the main trends in chemical data in both rivers and lakes. The outputs clearly demonstrate the benefits of achieving the emission reductions in both S and N compounds as agreed under the Gothenburg Protocol rather than making no further emission reductions. It was also clear that, besides the substantial reduction of SO4 deposition from the peak levels of the 1980s, N deposition must also be reduced in the near future to protect freshwaters from further acidification. Keywords: MAGIC, northern Italy, acidification, recovery, nitrogen saturation

  8. The nutrient forms, cycling and exchange flux in the sediment and overlying water system in lakes from the middle and lower reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper is a review of research works concerning the nutrient transportation,transformation and exchange between water, sediment and biota in the lakes from the middle and lower reaches of the Yangtze River conducted in the context of project entitled "The Processes and Mechanism of Lake Eutrophication in Middle and Lower Reaches of Yangtze River". All the lakes from this area are shallow lakes. According to the typical lake site research, the lakes from the middle and lower reaches of Yangtze River have a higher baseline of nutrition in the history. Normally the trophic status of these lakes can be categorized into medium-trophic or eutrophic. Human activities have been enhanced during the last decades, which speed up the lake eutrophic process. Lake eutrophication control needs to reduce not only the external nutrient inputs from watershed but also the internal loading from the sediments. Investigations revealed that the lake sediments in this area are considerablly high in nutrition in which at most about 30% of phosphorus exists in the form of bio-available in the sediment. The surface sediment will exert great effects on the nutrient exchange between water-sediment interface via adsorption and release of nutrient. The nutrient release from the sediment in these shallow lakes is mainly in two ways, i.e. in the undisturbed condition the nutrient is released through diffusion created by the nutrient gradient from sediment to overlying water; whereas in disturbed condition, the nutrient release is determined by the hydrodynamic forcing intensity and the sediment resuspension. Metallic elements such as the iron, manganese and aluminium and the aerobic-anaerobic ambience will affect the release of nutrients. The disturbed release will increase the total nutrients in the water column significantly in the short period. At the beginning of sediment resuspension, the dissolved nutrient concentration will increase. This increase will be damped if the ferric oxide and

  9. Performance Evaluation of Linear (ARMA and Threshold Nonlinear (TAR Time Series Models in Daily River Flow Modeling (Case Study: Upstream Basin Rivers of Zarrineh Roud Dam

    Directory of Open Access Journals (Sweden)

    Farshad Fathian

    2017-01-01

    Full Text Available Introduction: Time series models are generally categorized as a data-driven method or mathematically-based method. These models are known as one of the most important tools in modeling and forecasting of hydrological processes, which are used to design and scientific management of water resources projects. On the other hand, a better understanding of the river flow process is vital for appropriate streamflow modeling and forecasting. One of the main concerns of hydrological time series modeling is whether the hydrologic variable is governed by the linear or nonlinear models through time. Although the linear time series models have been widely applied in hydrology research, there has been some recent increasing interest in the application of nonlinear time series approaches. The threshold autoregressive (TAR method is frequently applied in modeling the mean (first order moment of financial and economic time series. Thise type of the model has not received considerable attention yet from the hydrological community. The main purposes of this paper are to analyze and to discuss stochastic modeling of daily river flow time series of the study area using linear (such as ARMA: autoregressive integrated moving average and non-linear (such as two- and three- regime TAR models. Material and Methods: The study area has constituted itself of four sub-basins namely, Saghez Chai, Jighato Chai, Khorkhoreh Chai and Sarogh Chai from west to east, respectively, which discharge water into the Zarrineh Roud dam reservoir. River flow time series of 6 hydro-gauge stations located on upstream basin rivers of Zarrineh Roud dam (located in the southern part of Urmia Lake basin were considered to model purposes. All the data series used here to start from January 1, 1997, and ends until December 31, 2011. In this study, the daily river flow data from January 01 1997 to December 31 2009 (13 years were chosen for calibration and data for January 01 2010 to December 31 2011

  10. Water quality of the Chokosna, Gilahina, Lakina Rivers, and Long Lake watershed along McCarthy Road, Wrangell-St. Elias National Park and Preserve, Alaska, 2007-08

    Science.gov (United States)

    Brabets, Timothy P.; Ourso, Robert T.; Miller, Matthew P.; Brasher, Anne M.

    2011-01-01

    The Chokosna, Gilahina, and Lakina River basins, and the Long Lake watershed are located along McCarthy Road in Wrangell–St. Elias National Park and Preserve. The rivers and lake support a large run of sockeye (red) salmon that is important to the commercial and recreational fisheries in the larger Copper River. To gain a better understanding of the water quality conditions of these watersheds, these basins were studied as part of a cooperative study with the National Park Service during the open water periods in 2007 and 2008. Water type of the rivers and Long Lake is calcium bicarbonate with the exception of that in the Chokosna River, which is calcium bicarbonate sulfate water. Alkalinity concentrations ranged from 63 to 222 milligrams per liter, indicating a high buffering capacity in these waters. Analyses of streambed sediments indicated that concentrations of the trace elements arsenic, chromium, and nickel exceed levels that might be toxic to fish and other aquatic organisms. However, these concentrations reflect local geology rather than anthropogenic sources in this nearly pristine area. Benthic macroinvertebrate qualitative multi-habitat and richest targeted habitat samples collected from six stream sites along McCarthy Road indicated a total of 125 taxa. Insects made up the largest percentage of macroinvertebrates, totaling 83 percent of the families found. Dipterans (flies and midges) accounted for 43 percent of all macroinvertebrates found. Analysis of the macroinvertebrate data by non-metric multidimensional scaling indicated differences between (1) sites at Long Lake and other stream sites along McCarthy Road, likely due to different basin characteristics, (2) the 2007 and 2008 data, probably from the higher rainfall in 2008, and (3) macroinvertebrate data collected in south-central Alaska, which represents a different climate zone. The richness, abundance, and community composition of periphytic algae taxa was variable between sampling sites

  11. Influence of Land Use/Cover Change on Storm Runoff——A Case Study of Xitiaoxi River Basin in Upstream of Taihu Lake Watershed

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Land use/cover change (LUCC) is one of the main boundary conditions which influence many hydrologic processes. In view of the importance of Taihu Lake Watershed in China and the urgency of discovering the impacts of LUCC on storm runoff, two flood events under five land cover scenarios in the Xitiaoxi River Basin of the upstream of Taihu Lake watershed were simulated by distributed hydrologic modeling system HEC-HMS. The influences of each land cover on storm runoffwere discussed. It was concluded that under the same rainstorm the ascending order of runoff coefficient and peak flow produced by the 5 different land covers were woodland, shrub, grassland, arable land,and built-up land; the descending order of swelling time were woodland, shrub, grassland, arable land, and built-up land. Scenario of built-up land was the first to reach peak flow, then arable land, grassland, shrub, and woodland.There were close relationships between the runoff coefficients produced by the 5 different land covers. The degrees of impacts on runoff coefficient of land cover change modes were sorted by descending: woodland to built-up land, shrub to built-up land, grassland to built-up land, arable land to built-up land, woodland to arable land, shrub to arable land,arable land to grassland, shrub to grassland, grassland to arable land, and woodland to shrub. Urbanization will contribute to flood disaster, while forestation will mitigate flood disaster.

  12. Mirror Lake genetic stock - Lower Columbia River Restoration Action Effectiveness Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 1) The purpose of this project is to measure changes in juvenile salmon habitat occurrence and health following restoration activities at the Mirror Lake Complex and...

  13. Mirror Lake salmon growth rate - Lower Columbia River Restoration Action Effectiveness Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 1) The purpose of this project is to measure changes in juvenile salmon habitat occurrence and health following restoration activities at the Mirror Lake Complex and...

  14. Mirror Lake salmon prey and diets - Lower Columbia River Restoration Action Effectiveness Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 1) The purpose of this project is to measure changes in juvenile salmon habitat occurrence and health following restoration activities at the Mirror Lake Complex and...

  15. Mirror Lake Fish catch composition - Lower Columbia River Restoration Action Effectiveness Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 1) The purpose of this project is to measure changes in juvenile salmon habitat occurrence and health following restoration activities at the Mirror Lake Complex and...

  16. The Lake Tahoe Basin Land Use Simulation Model

    Science.gov (United States)

    Forney, William M.; Oldham, I. Benson

    2011-01-01

    This U.S. Geological Survey Open-File Report describes the final modeling product for the Tahoe Decision Support System project for the Lake Tahoe Basin funded by the Southern Nevada Public Land Management Act and the U.S. Geological Survey's Geographic Analysis and Monitoring Program. This research was conducted by the U.S. Geological Survey Western Geographic Science Center. The purpose of this report is to describe the basic elements of the novel Lake Tahoe Basin Land Use Simulation Model, publish samples of the data inputs, basic outputs of the model, and the details of the Python code. The results of this report include a basic description of the Land Use Simulation Model, descriptions and summary statistics of model inputs, two figures showing the graphical user interface from the web-based tool, samples of the two input files, seven tables of basic output results from the web-based tool and descriptions of their parameters, and the fully functional Python code.

  17. Role of Minerogenic Particles in Light Scattering in Lakes and a River in Central New York

    Science.gov (United States)

    2007-09-10

    1) were selected to depict the effects of’ Cross Lake and Dreissena polyinorpha (zebra mussels ) me- Rivcr Olei Rir l tabolism, respectively. Dense...for a shallow (-3 m) unstrati- analysis: 18 planktonic (one for viruses, one for het- fled location in the southern end of Otisco Lake that erotrophic... effectively results in guided by the listings presented by Kerr and Rogers nine delineated particle classes. [34] and Woiniak and Stramski [351. The value

  18. Hydrodynamic modelling and characterisation of a shallow fluvial lake: a study on the Superior Lake of Mantua

    Directory of Open Access Journals (Sweden)

    Andrea Fenocchi

    2016-04-01

    Full Text Available This paper presents a numerical modelling framework developed to simulate circulations and to generally characterise the hydrodynamics of the Superior Lake of Mantua, a shallow fluvial lake in Northern Italy. Such eutrophied basin is characterised by low winds, reduced discharges during the summer and by the presence of large lotus flower (Nelumbo nucifera meadows, all contributing to water stagnation. A hydrodynamic numerical model was built to understand how physical drivers shape basic circulation dynamics, selecting appropriate methodologies for the lake. These include a 3D code to reproduce the interaction between wind and through-flowing current, a fetch-dependent wind stress model, a porous media approach for canopy flow resistance and the consideration of wave-current interaction. The model allowed to estimate the circulation modes and water residence time distributions under identified typical ordinary, storm and drought conditions, the hydrodynamic influence of the newly-opened secondary outlet of the lake, the surface wave parameters, their influence on circulations and the bottom stress they originate, and the adaptation time scales of circulations to storm events. Some probable effects of the obtained hydrodynamic characteristics of the Superior Lake of Mantua on its biochemical processes are also introduced.

  19. Seasonal Variations in δ18O of Inflowing River Water, Lake Water, Sediment Trap Material and Ostracod Shells of Lake Nam Co and its Catchment (Tibet, China) — a Proxy Calibration Study

    Science.gov (United States)

    Daut, G.; Wang, J.; Ju, J.; Plessen, B.; Fürstenberg, S.; Baade, J.; Frenzel, P.; Haberzettl, T.; Maeusbacher, R.; Zhu, L.

    2014-12-01

    δ18O is a very common proxy used in palaeoclimate studies all over the world, but for most parts of the world and especially the Tibetan Plateau modern studies that trace the pathway of this isotope from sink to source are lacking. In this study, financed by the BMBF (German Ministry of Science and Education, Project CADY), we present data that fill this gap. The study was performed in the terminal lake Nam Co, the biggest lake on the central Tibetan Plateau and its catchment. Water of the main tributaries to the lake, lake water at three different stations and from different water depths, bulk carbonate collected from different water depths with sediment traps and shells of living ostracods were collected for one year at lake Nam Co in approx. monthly intervals and analyzed for their δ18O values. The inflowing river waters mainly reflect the precipitation and show regional as well as seasonal variations depending on their location and on Monsoon or Westerly season but are in general on the global meteoric waterline. The lake water shows only minor vertical and spatial variations and is clearly off the meteoric waterline due to strong evaporation effects in this terminal lake. δ18O values of the bulk carbonate of sediment collected in sediment traps show only minor vertical and spatial variations during the year and the δ18O offset compared to the lake water is with around 1 ‰ quite small. Most probably this is attributed to chemical fractionation during formation of monohydrocalcite in the water column. In contrast δ18O values of ostracod shells are significant heavier than the lake water indicating isotopic fractionation (vital effect) during shell formation. In addition a seasonal variability is visible. The data of this proxy calibration study give now for the first time the opportunity to validate δ18O proxy data measured on core material from Lake Nam Co for their palaeoclimatic significance.

  20. Allochthonous subsidies of organic matter across a lake-river-fjord landscape in the Chilean Patagonia: Implications for marine zooplankton in inner fjord areas

    Science.gov (United States)

    Vargas, Cristian A.; Martinez, Rodrigo A.; San Martin, Valeska; Aguayo, Mauricio; Silva, Nelson; Torres, Rodrigo

    2011-03-01

    Ecosystems can act as both sources and sinks of allochthonous nutrients and organic matter. In this sense, fjord ecosystems are a typical interface and buffer zone between freshwater systems, glaciated continents, and the coastal ocean. In order to evaluate the potential sources and composition of organic matter across fjord ecosystems, we characterized particulate organic matter along a lake-river-fjord corridor in the Chilean Patagonia using stable isotope (δ 13C) and lipid (fatty acid composition) biomarker analyses. Furthermore, estimates of zooplankton carbon ingestion rates and measurements of δ 13C and δ 15N in zooplankton (copepods) were used to evaluate the implications of allochthonous subsidies for copepods inhabiting inner fjord areas. Our results showed that riverine freshwater flows contributed an important amount of dissolved silicon but, scarce nitrate and phosphate to the brackish surface layer of the fjord ecosystem. Isotopic signatures of particulate organic matter from lakes and rivers were distinct from their counterparts in oceanic influenced stations. Terrestrial allochthonous sources could support around 68-86% of the particulate organic carbon in the river plume and glacier melting areas, whereas fatty acid concentrations were maximal in the surface waters of the Pascua and Baker river plumes. Estimates of carbon ingestion rates and δ 13C in copepods from the river plume areas indicated that terrestrial carbon could account for a significant percentage of the copepod body carbon (20-50%) during periods of food limitation. Particulate organic matter from the Pascua River showed a greater allochthonous contribution of terrigenous/vascular plant sources. Rivers may provide fjord ecosystems with allochthonous contributions from different sources because of the distinct vegetation coverage and land use along each river's watershed. These observations have significant implications for the management of local riverine areas in the context of