Grantee Research Project Results

Final Report: Source Load Modeling for Sediment in Mountainous Watersheds

EPA Grant Number: R825433C027
Subproject: this is subproject number 027 , established and managed by the Center Director under grant R825433
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: UC Davis Center for Children's Environmental Health and Disease Prevention
Center Director: Van de Water, Judith
Title: Source Load Modeling for Sediment in Mountainous Watersheds
Investigators: Kavvas, M. Levant , Reuter, John E. , Goldman, Charles R.
Institution: University of California - Davis
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1996 through September 30, 2000
RFA: Exploratory Environmental Research Centers (1992) RFA Text |  Recipients Lists
Research Category: Center for Ecological Health Research , Targeted Research

Objective:

To improve the water quality of the lake, managerial actions will need to be taken in the tributary watersheds. To that end, we need a model that can evaluate various watershed management scenarios to find the best management practice. The primary objective of this research project was to develop a model that allows more accurate and effective prediction of sediment and phosphorous transport and their loads in mountainous Sierra Nevada watersheds under several possible management scenarios.

Accelerated erosion from natural and disturbed watersheds is one of the major factors contributing to the decline in the ecological health of the Lake Tahoe Basin. Erosive surface transport is the major source of sediment and phosphorous to the lake. Phosphorous has become the primary nutrient-limiting phytoplankton growth in the lake, and thus has an immense impact on the aquatic ecosystem. Therefore, controlling the delivery of sediment and its associated phosphorous is critical for the protection of aquatic resource(s).

Summary/Accomplishments (Outputs/Outcomes):

To fill the modeling need of decisionmakers, a comprehensive nonpoint source pollution model, Watershed Environmental Hydrology (WEHY), was developed and validated for one of the tributary watersheds in the Lake Tahoe Basin. The model consists of hydrologic and environmental modules that are physically based and spatially distributed. The physical basis of the model makes it possible for the model to be applicable to an ungauged basin because model parameters can be directly estimated from available physical information such as topography and soils. Another unique feature of this model is that spatially averaged (upscaled) governing equations are used for hydrologic and environmental processes. The use of upscaled governing equations allows the model equations to be scale consistent at any spatial resolution of model grid, because of their upscaled parameters. This gives the model the flexibility to choose a coarse level of grid resolution for the reduction of computational load when applied to a large watershed. The model results were very encouraging and appear promising for modeling nonpoint source pollution.

Subprojects R825433C028 and R825433C029 assess the impact of the nutrient load on the lake. Considering the hydrologic and geomorphologic features characteristic of mountain watersheds, ecological health is assessed as a response to changes and/or disturbances in the spatial distribution of terrestrial parameters. The results of this work provide invaluable tools for watershed managers to assess the costs and benefits of various management scenarios.

The following activities were accomplished:

• We developed a watershed model for the estimation of sediment and phosphorous loading to Lake Tahoe. This comprehensive watershed model simulates the hydrology and the fate of pollutants such as sediment and nutrient to accurately estimate the influx of sediment and phosphorous into Lake Tahoe for further analysis of lake water clarity. With this model, alternative management scenarios can be evaluated to find the best management practice that can minimize the disturbance within the watersheds to improve the water quality of Lake Tahoe. The model is thought to have significant potential to serve as a useful decisionmaking tool for taking managerial actions. It allows watershed managers to assess the cost/benefits of various policy scenarios.

• Two applications of WEHY to the Ward Creek Watershed in the Lake Tahoe Basin have shown that WEHY can reproduce the pattern of historical flow, sediment, and phosphorous loads with reasonable accuracy. Furthermore, the model performed consistently well for an independent data set. Overall comparisons were encouraging, and showed promise for the potential use of the WEHY model in studying the effects of different land management practices on ecological systems at both gauged and ungauged watersheds.

• The WEHY model is very effective at identifying the important hydrologic mechanisms of a basin of interest. Individual contributions from each hydrologic component of the model can be realistically identified by activating only that corresponding component. This would be difficult for traditional conceptual models to accomplish, as their hydrologic components do not physically model the hydrologic processes in question. Our model allows investigators to identify the individual hydrologic mechanisms involved in larger processes.

• The WEHY model provides a framework for testing the efficiency of soil conservation and erosion control techniques at local and regional levels, and provides approaches and tools for environmentally based watershed management. Overall, our research project enables agencies to set management priorities for reducing sediment and associated pollutants in watersheds.

Supplemental Keywords:

ecosystem, ecosystem protection, environmental exposure and risk, geographic area, international cooperation, water, terrestrial ecosystems, aquatic ecosystem, aquatic ecosystem restoration, aquatic ecosystems and estuarine research, biochemistry, ecological effects, ecological indicators, ecological monitoring, ecology and ecosystems, environmental chemistry, restoration, state, water and watershed, watershed, watershed development, watershed land use, watershed management, watershed modeling, watershed restoration, watershed sustainability, agricultural watershed, exploratory research environmental biology, California, CA, Clear Lake, Lake Tahoe, anthropogenic effects, aquatic habitat, biogeochemical cycling, ecological assessment, ecology assessment models, ecosystem monitoring, ecosystem response, ecosystem stress, environmental stress, environmental stress indicators, fish habitat, hydrologic modeling, hydrology, integrated watershed model, lake ecosystems, lakes, land use, nutrient dynamics, nutrient flux, water management options, water quality, wetlands., RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, INTERNATIONAL COOPERATION, Water, Waste, ECOSYSTEMS, Aquatic Ecosystem, Aquatic Ecosystems & Estuarine Research, Fate & Transport, Terrestrial Ecosystems, Aquatic Ecosystem Restoration, Watersheds, Monitoring/Modeling, Environmental Microbiology, Biochemistry, Water & Watershed, Ecology and Ecosystems, watershed management, ecological impact, restoration strategies, watershed restoration, watershed influences, hydrology, fate and transport, ecosystem stress, environmental stress, wetland restoration, sediment transport, integrated watershed model, aquatic habitat protection , ecology assessment models, land use, ecological research, Sierra Nevada, aquatic ecosystems, source load modeling

Relevant Websites:

http://ice.ucdavis.edu/cehr/ Exit

Progress and Final Reports:

Original Abstract

1997

1998

1999 Progress Report

Main Center Abstract and Reports:

R825433    UC Davis Center for Children's Environmental Health and Disease Prevention

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825433C001 Potential for Long-Term Degradation of Wetland Water Quality Due to Natural Discharge of Polluted Groundwater
R825433C002 Sacramento River Watershed
R825433C003 Endocrine Disruption in Fish and Birds
R825433C004 Biomarkers of Exposure and Deleterious Effect: A Laboratory and Field Investigation
R825433C005 Fish Developmental Toxicity/Recruitment
R825433C006 Resolving Multiple Stressors by Biochemical Indicator Patterns and their Linkages to Adverse Effects on Benthic Invertebrate Patterns
R825433C007 Environmental Chemistry of Bioavailability in Sediments and Water Column
R825433C008 Reproduction of Birds and mammals in a terrestrial-aquatic interface
R825433C009 Modeling Ecosystems Under Combined Stress
R825433C010 Mercury Uptake by Fish
R825433C011 Clear Lake Watershed
R825433C012 The Role of Fishes as Transporters of Mercury
R825433C013 Wetlands Restoration
R825433C014 Wildlife Bioaccumulation and Effects
R825433C015 Microbiology of Mercury Methylation in Sediments
R825433C016 Hg and Fe Biogeochemistry
R825433C017 Water Motions and Material Transport
R825433C018 Economic Impacts of Multiple Stresses
R825433C019 The History of Anthropogenic Effects
R825433C020 Wetland Restoration
R825433C021 Sierra Nevada Watershed Project
R825433C022 Regional Transport of Air Pollutants and Exposure of Sierra Nevada Forests to Ozone
R825433C023 Biomarkers of Ozone Damage to Sierra Nevada Vegetation
R825433C024 Effects of Air Pollution on Water Quality: Emission of MTBE and Other Pollutants From Motorized Watercraft
R825433C025 Regional Movement of Toxics
R825433C026 Effect of Photochemical Reactions in Fog Drops and Aerosol Particles on the Fate of Atmospheric Chemicals in the Central Valley
R825433C027 Source Load Modeling for Sediment in Mountainous Watersheds
R825433C028 Stress of Increased Sediment Loading on Lake and Stream Function
R825433C029 Watershed Response to Natural and Anthropogenic Stress: Lake Tahoe Nutrient Budget
R825433C030 Mercury Distribution and Cycling in Sierra Nevada Waterbodies
R825433C031 Pre-contact Forest Structure
R825433C032 Identification and distribution of pest complexes in relation to late seral/old growth forest structure in the Lake Tahoe watershed
R825433C033 Subalpine Marsh Plant Communities as Early Indicators of Ecosystem Stress
R825433C034 Regional Hydrogeology and Contaminant Transport in a Sierra Nevada Ecosystem
R825433C035 Border Rivers Watershed
R825433C036 Toxicity Studies
R825433C037 Watershed Assessment
R825433C038 Microbiological Processes in Sediments
R825433C039 Analytical and Biomarkers Core
R825433C040 Organic Analysis
R825433C041 Inorganic Analysis
R825433C042 Immunoassay and Serum Markers
R825433C043 Sensitive Biomarkers to Detect Biochemical Changes Indicating Multiple Stresses Including Chemically Induced Stresses
R825433C044 Molecular, Cellular and Animal Biomarkers of Exposure and Effect
R825433C045 Microbial Community Assays
R825433C046 Cumulative and Integrative Biochemical Indicators
R825433C047 Mercury and Iron Biogeochemistry
R825433C048 Transport and Fate Core
R825433C049 Role of Hydrogeologic Processes in Alpine Ecosystem Health
R825433C050 Regional Hydrologic Modeling With Emphasis on Watershed-Scale Environmental Stresses
R825433C051 Development of Pollutant Fate and Transport Models for Use in Terrestrial Ecosystem Exposure Assessment
R825433C052 Pesticide Transport in Subsurface and Surface Water Systems
R825433C053 Currents in Clear Lake
R825433C054 Data Integration and Decision Support Core
R825433C055 Spatial Patterns and Biodiversity
R825433C056 Modeling Transport in Aquatic Systems
R825433C057 Spatial and Temporal Trends in Water Quality
R825433C058 Time Series Analysis and Modeling Ecological Risk
R825433C059 WWW/Outreach
R825433C060 Economic Effects of Multiple Stresses
R825433C061 Effects of Nutrients on Algal Growth
R825433C062 Nutrient Loading
R825433C063 Subalpine Wetlands as Early Indicators of Ecosystem Stress
R825433C064 Chlorinated Hydrocarbons
R825433C065 Sierra Ozone Studies
R825433C066 Assessment of Multiple Stresses on Soil Microbial Communities
R825433C067 Terrestrial - Agriculture
R825433C069 Molecular Epidemiology Core
R825433C070 Serum Markers of Environmental Stress
R825433C071 Development of Sensitive Biomarkers Based on Chemically Induced Changes in Expressions of Oncogenes
R825433C072 Molecular Monitoring of Microbial Populations
R825433C073 Aquatic - Rivers and Estuaries
R825433C074 Border Rivers - Toxicity Studies