Grantee Research Project Results

Final Report: Modeling Transport in Aquatic Systems

EPA Grant Number: R825433C056
Subproject: this is subproject number 056 , 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: Modeling Transport in Aquatic Systems
Investigators: Mount, Jeff
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:

The objective of this research project was to gather baseline information about sediment sources and potential sinks within the Sacramento Valley Watershed to develop multiple models. Using an array of geochemical, petrographic, geomorphic, and paleomagnetic techniques, we conducted experiments to identify potential source areas. In addition, distributional databases were developed to experiment with modeling potential nonpoint sources of sediment, and to identify the role of changing land use/land cover in changing sediment yields.

Summary/Accomplishments (Outputs/Outcomes):

We incorporated the bulk of the data and methods generated in the project into the modeling of hydrography, toxic substance transport, and population biology in several Center for Ecological Health Research projects, as described in other reports. We used this information to define more accurate loads and timelines of sediment and mercury inputs into the bay-delta projects (e.g., R825433C004, R925433C005, R825433C009) and time series analyses (R825433C058), and to refine the analysis of both the upstream sources and downstream fate of sediment, particularly in the Clear Lake Basin (R825433C015, R825433C017, R825433C019). Spatial data from the geographic information system (GIS) studies (R825433C055) were developed to look for geological, climatological, and land cover attributes associated with high nonpoint source loads. This information was developed to aid outreach activities assisting the U.S. Environmental Protection Agency Region 9 and the state and regional water boards in evaluating total maximum daily load issues, and in assessing and managing risks associated with sedimentation and nonpoint inputs at the watershed level (R825433C059).

During the course of this research, we experimented with various methods to address some of the major unknowns in modeling nonpoint sources of sediment. In the Clear Lake/Cache Creek Watershed, we experimented with bulk geochemical analyses of suspended load samples taken throughout the watershed and from the lake. Although rock type varies considerably within the Cache Creek Watershed, bulk geochemistry did not vary sufficiently to allow discrimination of the source areas. In addition to performing geochemical analyses, we analyzed the magnetic properties of bulk samples to identify a broad range of sources of ferromagnetic minerals. Time-series analysis of magnetic and textural properties of sediments in Clear Lake cores showed changes in magnetic properties roughly coincident with changes in water content, organic content, and grain size of the lake sediments. These observations appear linked to significant shifts in sediment sources in the watershed.

To address potential changes in sediment source areas through time, we conducted a series of GIS-based simulations to evaluate the role of land conversion in changes in sediment yields in the basin. A modified universal soil loss equation-based model simulated relative changes in annual sediment yield over the past 150 years. These simulations indicate that the conversion of shrub and brush lands to grazing lands, which culminated in the late 1800s/early 1900s followed by conversion to orchards and row crops in the early 1900s, may have created a disproportionate influence on changing sediment yields within the basin.

The sediment transport and source work conducted under this research project were expanded to include issues associated with sediment erosion and deposition and their impact on channel and floodplain restoration in the Central Valley. A series of geomorphic analyses were conducted on the lower Cosumnes River within its alluvial reaches to address the impacts of land management on channel incision and associated increases in sediment budgets. This work was coupled with studies in the lowermost Cosumnes River that evaluated the importance of floodplains as potential storage sites for sediment. Active restored floodplains have the potential to store significant volumes of sediment produced by land use changes within the watershed.

The following activities were accomplished:

• We attempted to develop new geochemical methods for assessment of nonpoint sources of sediment. Although this work was ultimately unsuccessful because of a lack of significant geochemical variability in sources, we established methods for use in future studies.

• We developed time-series analyses of magnetic properties of lake cores. This work demonstrated significant changes in mineralogy, abundance, and size of Clear Lake's magnetic minerals that appear to coincide with basin-scale land use changes. This may provide investigators and managers with an inexpensive method of detecting significant changes in sediment yields in watersheds that have reservoirs or lakes.

• We constructed a GIS-based erosion model that accounts for relative changes in sediment yields associated with historic land use changes. This model was used to test hypotheses regarding the influence of land conversion within the Clear Lake Basin on lake sedimentation rates.

• We developed detailed assessments of the impact of channel incision on sediment yields. This work, conducted on the Cosumnes River, evaluated the impacts of river management methods and geologic conditions on rivers undergoing incision. Our results will be useful to environmental managers and conservationists.

• We demonstrated the importance of restored floodplains as fine sediment storage sites in alluvial rivers. This work documented how reconnections between historic floodplains and present-day channels can be used to reduce fine sediment loads through sand splay deposition. This work also evaluated the habitat restoration benefits of these approaches. Our findings may be beneficial to environmental managers and investigators working on similar projects.

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, 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, ecosystem assessment, ecological impact, restoration strategies, watershed restoration, groundwater contamination, ecological models, ambient particle properties, aquatic, hydrology, watershed influences, material transport, environmental stress, fate and transport, sediment transport, ecosystem stress, integrated watershed model, wetland restoration, water circulation, ecological research, ecology assessment models, chemical kinetics, contaminant transport models, transport modeling, aquatic ecosystems, modeling, watershed sustainablility, Clear Lake

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