Wetlands Restoration

EPA Grant Number: R825433C013
Subproject: this is subproject number 013 , 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: EERC - Center for Ecological Health Research (Cal Davis)
Center Director: Rolston, Dennis E.
Title: Wetlands Restoration
Investigators: Rejmankova, Eliska
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


The project seeks to examine the effects of wetland disturbance on the nutrient budget of Clear Lake.


The investigators research in Clear Lake and marshes surrounding the lake addresses the effects of wetlands on the lake water quality. They do this by examining 1) how wetland plant species can affect nutrient budgets, 2) how much of the nutrients can be retained in wetland sediment before getting into the lake, 3) how much the sedimentation rate of soil and nutrients has changed since watershed modification by humans. The increased understanding of the role of wetlands in Clear Lake watershed gained through our research project provides important guidelines to the on-going restoration project and wetland management.

In previous years they addressed the selection of plant species for restoration project, the effect of an aquatic fern on the nutrient budget of emergent macrophytes in terms of mass balance approach, and the change of plant communities in the watershed and wetlands through pollen analysis of three sediment cores, CL-UA-02, CL-UA-03, and CL-OA-03.

A large wetland on the northwest side of the Clear Lake has been diked, drained, and used for agriculture for many years while Anderson Marsh on the southeast side of the Clear Lake has been little impacted by agricultural activities. These changes around Rodman Slough lead to an increase of water current and as a result, decrease in sedimentation of small particles in the marsh and on slough bottom. Nutrients input, such as nitrogen and phosphorus, has been increased from the use of fertilizers.

To assess the response of Clear Lake wetland sediments to recent environmental changes caused by watershed modification, physical and chemical properties of sediment cores at the inlet and outlet were compared. The sediment in Rodman Slough is allochthonous (sand) and has very little organic matter but that in Anderson Marsh is autochthonous (peat) and has high organic content. Concentrations of C, N, P, Ca, K, and Na in Rodman Slough sediment were lower than those of Anderson Marsh sediment. Accumulation rates of P, Ca, and K were much higher in Rodman Slough than in Anderson Marsh, while accumulation rates of C, N and Na were similar at both locations. Water and sediment analyses showed that the excess P and N, originating from agricultural activities, reach Clear Lake through Rodman Slough and were removed in the lake. Major cations (Ca, Mg, K, and Na) concentrated in the lake through evaporation and transpiration. 210Pb dating showed an increase in sedimentation rate since the 1930s.

Expected Results:

Previous studies were focused on wetland plants and the historical records because wetlands function as "nutrient sinks" and their presence can act to lessen the load of nutrients from agricultural usage to lake. These studies provided investigators with a basic knowledge of and data on the biogeochemical properties of marshes in the Clear Lake basin. To reduce the input of nutrients into the lake from the watershed, Middle Creek restoration project is continuing. It is very important to monitor the change in sediment characteristics that result from the restoration project and other environmental changes. Based on our results and future monitoring, the direction of the restoration project can be evaluated and modified.

Even though this sub-project has ended, the ongoing habitat restoration projects in the Clear Lake Basin need much more research and offer considerable opportunities for scientific investigation. Additional work needed includes research on the long-term historical records, the ecology of species commonly for restoration, especially the establishment techniques, and the success rates and ecological effects of restored habitats. Also, the results of these investigations should receive a large-scale test.

Supplemental Keywords:

watershed, aquatic ecosystem restoration, Clear Lake, macrophytes, plant species, nutrients, sediment transport, biogeochemical properties., RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Water, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, Water & Watershed, Restoration, Aquatic Ecosystem, Environmental Microbiology, Biochemistry, Environmental Monitoring, Terrestrial Ecosystems, Ecology and Ecosystems, Aquatic Ecosystem Restoration, Watersheds, anthropogenic stress, contaminant exposure, nutrient transport, watershed management, biodiversity, fish habitat, Clear Lake watershed, mercury, agricultural watershed, nutrient flux, marine biology, nutrients, marine biogeochemistry, wetland plant species, restoration strategies, Clear Lake, wetland restoration, integrated watershed model, aquatic ecosystems, environmental stress, lake ecosysyems, water quality, ecosystem stress, ecological impact, aquatic habitat protection , ecological research, restoration planning

Progress and Final Reports:

  • 1997
  • 1998
  • 1999
  • Final Report

  • Main Center Abstract and Reports:

    R825433    EERC - Center for Ecological Health Research (Cal Davis)

    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