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2000 Progress Report: Modeling Ecosystems Under Combined Stress
EPA Grant Number: R825433C009Subproject: this is subproject number 009 , 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: Modeling Ecosystems Under Combined Stress
Investigators: Orlob, Gerald
Institution: University of California - Davis
EPA Project Officer: Levinson, Barbara
Project Period: October 1, 1996 through September 30, 2000
Project Period Covered by this Report: October 1, 1999 through September 30, 2000
RFA: Exploratory Environmental Research Centers (1992)
Research Category: Center for Ecological Health Research , Targeted Research
Description:
Objective:To combine unsteady hydrodynamic and water quality simulations in the Sacramento River that compliment the studies of other Center researchers on fate and transport of toxicants, algal and other food web productivity, and fisheries biology.
Progress Summary:The central focus of present research remains on development of management strategies for sustainable aquatic ecosystems, including finding practical solutions for preservation of threatened and endangered aquatic species. Such solutions require improved understanding of riverine ecosystem behavior under stress. Effects of natural and anthropogenic stresses have been especially notable in species that are sensitive during their life cycles to shifts in water quantity and quality, such as Pacific salmon and striped bass. In northern California populations of winter-run Chinook salmon have declined in recent years to the point that they are now considered an endangered species. Juveniles of the winter run are subject to many environmental stresses as they run the gauntlet from spawning grounds to the sea. Initial applications of a mechanistic ecosystem model, called SAMTRK, have been used in this project to investigate impacts of flow regimes, water temperatures, and salinity on survival, growth and migration of this species in the Sacramento River and through the San Francisco Bay/Delta system. Other researchers at the Center are applying the hydrodynamic and water quality models developed in this project together with similar ecosystem response modeling to simulate the early life stages of striped bass, another threatened species that inhabits the estuarine system. The models were used initially to replicate historical conditions and later to verify that these tools correctly represent important physical, chemical and biological processes affecting behavior of the subject aquatic species. Having been calibrated and verified for a wide range of historic hydrologic conditions, the models are presently in condition to be utilized as tools for analysis of proposed management alternatives for preservation of ecosystems in the Sacramento River and Bay/Delta estuary.
CALFED Bay/Delta Program. Current research activities address management alternatives alternatives proposed by the CALFED Bay/Delta Program, a cooperative interagency organization designed to develop and implement practical solutions for management of fish and wildlife, water supply, flood control and water quality in the Bay/Delta system. CALFED activities include development of measures to minimize conflicts among competing environmental, municipal and agricultural demands on limited water resources. To address these issues CALFED is proposing specific structural and operational modifications of Delta water transfer to improve water supplies, enhance water quality and improve ecosystem health. Among options under consideration are: (1) channel enlargements in the Delta that would allow expansion of the Banks Pumping Plant to its full capacity. (2) construction of canal with a capacity of up to 15,000 cubic feet per second that would convey water from the vicinity of Hood in the northern Delta, around the Central Delta, to the export facilities in the southwestern Delta, and (3) construction of an intertie between state and federal pumping facilities in the southern Delta. These options would be designed to minimize adverse impacts on the ecosystems, like entrainment of juvenile fishes or changing habitat conditions, while at the same time increasing operational flexibility in meeting water supply targets. In this research impacts of the various proposed CALFED alternatives on water supplies and water quality in the Delta are being estimated with the models along with potential effects on survival and out-migration of juvenile Chinook salmon. Result of this analysis may be incorporated into other ecosystem health projects being conducted by Center researchers. Additionally, the predicted impacts of CALFED alternatives on salmonids provide base lines for comparable assessments of effects on distributions of striped bass populations in the system.
Model Application. During the past year substantial progress has been made in further calibrating and verifying the performance of hydrodynamic and water quality models of the Sacramento River and Bay/Delta system. Simulation results for selected scenarios have been compared to actual field observations to ensure that the models provide credible representations of the dynamic responses of the modeled environments. Simulations for the purpose of calibrating hydrodynamics (flows, velocities and water levels) and water quality (temperatures and salinities) have been completed for a low flow period (April 1992 through June 1993. This period, occurring near the end of a prolonged six-year drought, was selected for Chinook salmon analysis because it includes the most stressful conditions in recent history and is a period for which reliable field data are available. Fortuitously, it also encompasses two striped bass spawning cycles. Striped bass modeling analysis was focused on two distinct hydrologic year types: 1992 classified as "critical" (extremely dry) and 1993 classified as "above normal" (relatively wet). Preliminary simulations for the period June-April 1984 have been performed to represent striped bass population dynamics during an extremely wet year. These periods were chosen in part because of the availability of an extensive database on actual striped bass populations in the Delta.
As calibration simulations were completed, application of the models to the proposed CALFED alternatives commenced. Simulations were performed for options considered representative of key operational characteristics of four distinctive options: (1) increased Delta export pumping by 50 percent; (2) increased Delta export pumping by 100 percent (but limited by the maximum export pumping capacity); (3) modified Delta channels with levee setbacks on the Mokelumne River and dredging of Old River; and (4) incorporation of diversions through a so-called "isolated facility" extending from Hood in the northern Delta to Clifton Court Forebay at the head of the SWP and CVP pumping facilities in the southwestern Delta. Model results for these options indicated significant impacts of structural and operational modifications on Delta flows, circulation patterns, and salinity distributions within the Delta channels. Flow magnitudes increased in both north and south Delta regions where stream channel enlargements were proposed. Although flow magnitudes generally increased with enlarged channel cross-sections, velocity changes were small in these regions of the Delta.
Impacts of the various scenarios on water quality were found to be most prominent in the Isolated Facility (IF) case. The focus was on salinity change because of potential detriment of high salinities to both agricultural and urban uses. Two scenarios were examined in detail: (1) a base case with withdrawals under existing conditions at Clifton Court Forebay operation and (2) an operational case with withdrawal into the IF at Hood. Simulation results indicate that multiple withdrawal capability is important for salinity intrusion control, especially in dry and critical years. On the other hand, a facility like the IF was found to be only marginally effective in regulating water quality under either normal or wet hydrological conditions.
Potential impacts of these alternatives on juvenile winter-run Chinook salmon were assessed using the several models, including SAMTRK. For all three of the major alternatives the numbers of juveniles decreased, primarily due to increased losses at diversion locations. For the increased pumping and channel modification scenarios, increased flow toward the pumps was found to increase losses by entrainment. Prior to analysis of simulation results it was believed that an isolated diversion facility might decrease salmon losses in the southern Delta, merely by reducing diversions. Although simulation results did indicate that losses of juveniles in the South Delta would decrease for the case of diversion through an IF at Hood, the overall salmon loss actually increased due to very large losses at the intake, losses that might be mitigated by screening. The proposed canal intake at Hood is aligned with the main stem of the river through which all downstream migrants must pass. Losses of juvenile salmon at this facility would be proportional to the flow diverted from the main stem of the Sacramento River and a function of screening efficiency, a factor now being investigated with the models.
Future Activities:Collaboration among the investigators in the Center is demonstrated in part by development of a suite of interactive models designed to assess impacts of multiple stresses on ecosystems. Specific efforts are being made to link modeling approaches. A common ground among modelers in this project is a perceived ability to characterize the relationships between watershed properties, agricultural processes, hydrodynamics of both surface and ground waters, water quality, toxicant loadings, and ecological responses. In a demonstration of this concept surface and ground water models have been linked to simulate the fate and transport of the pesticides from agricultural lands in the Feather River watershed to the estuarine environment of the Delta where aquatic species may be impacted. Simulated loadings of the pesticide diazinon are delivered to the surface water hydrodynamic and water quality models by "wash off" from treated agricultural areas, then transported into the Delta where it may be further diluted and dispersed. Results of this integrated application of the models are distributions of the pesticide in Delta channels that may affect sensitive species, the responses of which can be represented in SAMTRK or the companion striped bass model.
Supplemental Keywords:Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, RFA, Ecosystem/Assessment/Indicators, Biology, exploratory research environmental biology, Ecology, Aquatic Ecosystems & Estuarine Research, Ecological Risk Assessment, Aquatic Ecosystem, Ecological Indicators, Biochemistry, Ecological Effects - Environmental Exposure & Risk, Ecosystem Protection, Ecology and Ecosystems, ecosystem response , riverine ecosystems, modeling biological effects, modeling chemical effects, river systems, chinook salmon, combined stresses, riverine ecosystems , Sacramento River, aquatic ecosystems, environmental stress, multiple pollutants, ecosystem, modeling, rivers, ecosystem stress, ecosystem response, multiple stressors
Progress and Final Reports:
Original Abstract
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