Grantee Research Project Results
Final Report: An Integrated Approach to Assessing Water Management Options in a Major Watersheds: Extending a Hydrodynamic-Water Quality Model to Include Biological and Politico-Economic Components
EPA Grant Number: R825285Title: An Integrated Approach to Assessing Water Management Options in a Major Watersheds: Extending a Hydrodynamic-Water Quality Model to Include Biological and Politico-Economic Components
Investigators: Sabatier, Paul A. , Quinn, James , Weinberg, Marca , Bennett, Bill , Rhodes, Cathy , Loeb, Curtis , Slotton, Darell , Orlob, Gerald , Anderson, Jamie , Lund, Jay , Mount, Jeff , Botsford, Louis , Johnson, Mike , Richerson, Peter , Moyle, Peter , Suchanek, Thomas
Institution: University of California - Davis
EPA Project Officer: Packard, Benjamin H
Project Period: December 1, 1996 through November 30, 1999 (Extended to September 30, 2000)
Project Amount: $1,292,627
RFA: Water and Watersheds Research (1996) RFA Text | Recipients Lists
Research Category: Watersheds , Water
Objective:
The objectives of this research project were to:
- Refine the Resource Management Associates, Inc (RMA) hydrodynamic-water quality finite element model of the Sacramento River and Delta system simulating flows, temperature, and salinity.
- Expand and integrate this model to include: (a) estuarine and riparian habitat and indigenous ecosystems, (b) inflow and contaminants from tributary watersheds, (c) the economics of agricultural and urban water use, and (d) the effects of the above on water quality and selected fish populations.
- Use the integrated set of models to explore the impacts of a variety of management scenarios seeking to optimize politically important fish populations at risk with agricultural and urban water demands.
- Understand the political context in which water decisions are being made and the role that scientific information plays in that process.
Summary/Accomplishments (Outputs/Outcomes):
Hydrodynamics and Water Quality. This project began with relatively well-developed hydrodynamic (RMA-2) and water quality models (RMA-11) of the Sacramento River and Delta dealing with temperature, flows, and salinity. As part of this research project, the hydrodynamic and water quality models were improved and applied to the Sacramento watershed, including the Bay/Delta, in the following ways:
- The Delta portion of the hydrodynamic model was dramatically improved by using a finer grid and better hydrologic data than were previously available.
- The model was extended to the San Francisco Bay using a two-dimensional depth-averaged representation. (The Sacramento River and Delta are modeled in one dimension.)
- A separate particle-tracking model was greatly improved. This was critical to the overall project, because fish larvae and very young adults are seeded as particles in the system.
- The hydrodynamic and water quality models were modified to accommodate data at half-hour, hourly, or daily intervals.
- The hydrodynamic model was calibrated to historical data from the California Department of Water Resources (DWR), the U.S. Geological Survey (USGS), and the National Oceanic and Atmospheric Administration (NOAA). A 15-month period, April 1992-June 1993, which corresponds to the critical April-June period for striped bass for both years and to the 15-month freshwater rearing period of winter-run Chinook salmon, was chosen for the principal calibration. We compared hydrodynamic simulation results to field data to ensure that the model provides a reasonable representation of the system. Simulations also were completed for April-June 1984, a normal year.
- Water quality simulation results were compared to field data from DWR and USGS to ensure that the model provides a reasonable representation of the system. Calibration efforts focus on adjusting wind-based evaporation coefficients until simulated results provided acceptable agreement with field data. Similarly, salinity changes within the system, ranging from freshwater river flows to ocean water at Golden Gate, are represented in the model. Calibration efforts for salinity focused on modifying hydrodynamic eddy dispersion coefficients and providing a representation of salinity of agricultural return flows until the simulated salinity gradients matched field data. Simulations also were completed for April-June 1984, a normal year.
- Riparian areas along the main step of the Sacramento River and major tributaries (up to about 2,000 feet) were mapped and the effects of shading on water temperature were included in the water quality model.
The hydrodynamic and water quality models were applied in a predictive capacity to quantify the effects of management alternatives on hydrodynamic and water quality characteristics. These characteristics include water velocities and directions of flows (circulation), salinity, and water levels in the South Delta. Three time periods were adopted to illustrate relative effects of potential operational and structural alternatives through a range of hydrological periods.
The management alternatives were taken from those formally envisaged by either CALFED (a consortium of state and federal agencies and stakeholders) or the Central Valley Project Improvement Act of 1992. These include: (1) channel enlargements that would allow expansion of the capacity of the pumping plant at the head of the California Aqueduct (a primary component of the California State Water Project); (2) an isolated canal with a capacity of 5,000 cfs up to 15,000 cfs that would convey water from the North Delta, around the Central Delta to export facilities in the South Delta; and (3) an intertie or connection between state and federal pumping projects in the South Delta designed to reduce entrainment and other harmful effects on sensitive species by increasing operational flexibility (e.g. allowing alternative diversion locations and at times, among others).
Model simulations of historical conditions were compared to those of the management scenarios so that the effects of the proposed changes could be evaluated. Based on analyses of these simulations, the following conclusions were made (see Loeb, 2001 for details):
- Channel modifications, including dredging and channel widening in the South Delta, would allow the pumping capacity of nearby export facilities to be realized without increasing channel scour or having other detrimental effects.
- Modifications in the North Delta would improve conveyance capacity of these channels without undermining flood control capacities in the region.
- Under low Delta inflows and with diversions up to 50 percent greater than those of the base case, operation of an isolated facility would provide withdrawals of substantially improved water quality with respect to that of withdrawals at existing diversion locations under similar conditions.
- During dry years, tidal salinity would not encroach far enough upstream in the Sacramento River to jeopardize water quality in the vicinity of an isolated facility.
In addition to the RMA models, we used a neural net analysis to provide rapid assessment of the effect of water management options on salinity throughout the Delta. It was a relatively inexpensive, fast, and accurate method for evaluating salinity in the system.
Fisheries. This project has examined several different fish species. In two of them, striped bass and winter-run Chinook salmon, we used two particle/organism transport models extended for partially explicit individual-based mechanistic modeling of fish populations, thus potentially integrating hydrodynamics, water quality, and ecological processes. Our approach involves formulating models of individual fish based on available information on life history and response to environmental conditions (e.g., the dependence of growth and mortality rates on temperature and salinity) and introducing groups of fish as particles in the context of the hydrodynamic and water quality models for specific time periods. We also examined two other politically and ecologically important species, the Delta smelt and Sacramento splittail, but in a less rigorous fashion.
Striped Bass. We chose striped bass as an example for several reasons. First, more data are available on its distribution and abundance than on any other fish in the Delta. Second, it supports a politically important sport fishery. Third, the decline in striped bass in the 1970s was an early indicator of declining ecosystem health in the Delta.
We used the striped bass Egg and Larval Survey (ELS) data archived by the Interagency Ecological Program (IEP) in conjunction with an individual-based model of striped bass egg and larval growth and survival formulated from relationships available in the literature. The result of this effort was a method for taking the egg data (location, time, number, young or old age) from the ELS database, modeling the time of spawning from the young/old age data, temperature taken from the water quality model, and the published field observation that eggs are spawned at night. Using this technique, eggs were seeded into the hydrodynamics/water quality model for each water year based on the ELS data for that year. The simulation was integrated forward in time and at the end of the simulation, the number of eggs and larvae were contoured on size and time for six spatial regions within the Sacramento/San Joaquin system. The correspondence between the data, spatially contoured as described above, and the model output was excellent.
Results of modeling striped bass egg and larval survival and development for the management scenarios were treated as a series of case studies that mimicked some of the characteristics of management options being discussed under the CALFED agreement and under the Central Valley Project Improvement Act (CVPIA). We examined four CALFED scenarios and two CVPIA scenarios for each of the 3 water years. Two of these showed large effects upon the striped bass numbers and distribution. Increasing the pumping in the south delta by 100 percent caused a "reverse flow" toward the pumps in the average and dry years (1984 and 1992), decreasing the number, especially the number of larger size groups, as they were entrained at the south delta diversion pumps. The management scenario that showed the largest effect on the striped bass model population was the CVPIA scenario, whereby water from the San Joaquin River was reallocated to the delta rather than being pumped out. There was a large benefit to the striped bass population of the increased flow on the San Joaquin in moving the individuals away from the pumps resulting in few individuals entrained.
Winter Run Chinook Salmon. Winter-run Chinook salmon were selected for analysis because they are of immense political significance as a cultural icon that has been listed under both the California and Federal Endangered Species Act since 1990. There also is a fair amount of historical data on salmon, although not nearly as extensive as for striped bass. Finally, they are an ecological indicator for the entire Sacramento watershed, as adults spawn in upstream tributaries, juveniles rear in the river and delta, and smolts travel through the delta to the ocean, and 2-3 years later, adults return through the delta to spawn in upstream tributaries.
To assess the impacts of management alternatives on species sensitive to environmental stresses, a mechanistic approach was developed that integrates mathematical hydrodynamic, water quality, and ecological models. A hydrodynamic model, RMA-2, provides dynamic descriptions of water velocity and depth throughout modeled riverine and estuarine systems based on reservoir operations, system withdrawals, tributary inflows, and tidal influences. Simulated hydrodynamics are utilized by a companion water quality model, RMA-11, to simulate water quality constituents such as water temperature and salinity. Finally, the combined outputs of the hydrodynamic and water quality models provide descriptions of the physical and chemical environment to an ecological model, SAMTRK (Anderson, 2001), a particle-tracking model developed in this research to simulate survival and out-migration of individuals or groups of juvenile Chinook salmon.
Several proposed water resource management alternatives were examined with the new methodology to assess potential impacts on juvenile Chinook salmon. Scenarios that increased flow towards the pumps by either increasing pumping rates or dredging channels to increase flow capacity showed corresponding increases in juvenile salmon loss at the pumping facilities. Scenarios also were examined for diversion of water from the main stem of the Sacramento River into a proposed canal, known as the Isolated Facility, that bypasses the delta and delivers water directly to Clifton Court Forebay. Large losses of juvenile salmon occurred at the screened intakes to the Isolated Facility along the main stem of the Sacramento River. The efficiency of the screens at the intake facility was demonstrated to be an important factor in juvenile salmon survival.
Delta Smelt and Sacramento Splittail. Until recently, both of these listed species had been poorly studied. Information had to be compiled from a number of largely unpublished studies by agency biologists or developed from new studies. With additional funding from CALFED, the original limited objectives were expanded to include a general review of the biology of both species and to develop additional analyses and models.
The two main objectives of the work on Delta smelt were to: (1) identify the degree to which particle-tracking models can assume that young smelt are carried as passive particles by water-flows in regard to season or location in the system; and (2) identify factors influencing the population dynamics of the threatened Delta smelt. A field-study was designed to determine the relationship between larval fishes, including smelt, and the hydrodynamics of the mixing-zone at the interface between freshwater and saltwater in Suisun Bay (Bennett, et al., 2002). The results indicated that Delta smelt migrated vertically once they had developed functioning swim-bladders. Particle-tracking models will thus need to incorporate specific vertical migration behaviors to simulate organism movements through the system.
Like larval behavior, relatively little is known of the factors influencing the Delta smelt population. To support population modeling efforts, a review of existing information and data exploration analyses were conducted, using a variety of long-term databases maintained by the Interagency Ecological Program (IEP) (Bennett, 2000). The results have three key implications for future population modeling. First, Delta smelt were previously thought to be an annual species. However, auto-correlation analysis of the annual abundance data suggested Delta smelt may have a 2-year life cycle; this pattern also is supported by recent aging studies. Second, basic stock-recruitment analyses suggested that in some years the population can undergo density dependent regulation between the juvenile and adult life stages. Third, exploratory correlations were found among a variety of environmental stressors, Delta smelt mortality rates, and abundance indices. These results suggest that entrainment, water export operations, declining food abundance, and exotic predators can be working individually or synergistically to regulate the population. There also is evidence that toxic chemicals in agricultural runoff co-occur with post-larval smelt during late spring. Overall, these results provide a conceptual framework of Delta smelt life-history and factors influencing abundance that will serve as an essential starting point for future efforts to model the population.
As with the Delta smelt, a review of existing information on Sacramento splittail was conducted using a variety of long-term databases maintained by the IEP (Moyle, et al., 2001). Given the high fecundity of splittail and their ability to tolerate a wide variety of environmental conditions, the key to their long-term conservation is providing adequate spawning and rearing habitat and preventing excessive mortality of upstream migrating adults and downstream migrating juveniles. Simulation models of the splittail population suggest that a self-sustaining splittail population requires: (1) flow regimes of inflowing rivers that result in periodic inundation of riparian habitats in lowland areas during winter and spring, (2) relatively safe migration corridors between spawning and rearing habitats with adequate flows to quickly move juveniles downstream; and (3) an abundance of brackish, shallow-water rearing habitat.
Economic Analyses. The economic modeling for this research project has occurred in two relatively distinct segments. Jay Lund and his students initially focused on urban water demand, but this was soon expanded into a much larger model (CALVIN) of the entire California water system. Marca Weinberg and her students focused on the agricultural sector, and it was her analysis that formed the basis for the integrated modeling effort (Weinberg, et al., 2002). However, there was some integration of the two economic models. For example, a portion of the systemwide CALVIN model was used to convert the annual water demand in the agricultural models into monthly water demand. This was critical for the multidisciplinary synthetic modeling project, because the hydrologic and fishery models operate on monthly (or hourly) scales.
The CALVIN model is driven by economically based objective functions for urban and agricultural water use, with environmental water uses (e.g., salinity standards, delta pumping constraints) represented as flow constraints. This allows analysis of the economic impacts of environmental flow constraints under a variety of conditions from heavy dependence on historical water allocations to virtually unlimited water marketing. In addition, different environmental constraints in the optimization model can be used to determine the most efficient allocation of shortages, and these shortages can in turn be used as inputs to the hydrologic, water quality, and fishery models. Thus, the urban water economics work of this Sacramento watershed grant contributed to the development of CALVIN, and the larger modeling work helped fill one of the major gaps in the Sacramento watershed project: the lack of a system model to relate environmental and operational decisions to urban and agricultural water deliveries. Some of the major conclusions for the Sacramento Valley region are:
- Spatial aggregation can be an important determinant of water operation, allocation, and delivery results, but past a reasonable level of dissaggregation, there are few effects.
- Projecting current water management and allocations to year 2020 water demands, the estimated average annual economic losses to urban water users in California is $1.6 billion. These economic losses range from zero in most parts of the Sacramento Valley to as much as $1,000/year/capita in Southern California.
Irrigated agriculture is the dominant land use in the Sacramento watershed, and it accounts for roughly 80 percent of basin water diversions, including 12 million acre-feet (maf) (14.4 km3) that are consumptively used each year. To assess the effect of alternative water management strategies on agricultural production, we used the Central Valley Production Model (CVPM). The CVPM is a nonlinear, positive mathematical programming model designed to replicate farmer decisionmaking in response to alternative water price and availability scenarios. We use the CVPM to predict how cropping patterns, profit, production technology costs, and commodity pricing change across 21 subregions in response to changes in water allocation. These subregions are aggregated into three major regions: the Sacaramento Valley, the Westside San Joaquin Valley, and the Eastside San Joaquain. Weinberg and her colleagues first analyzed a series of base-case scenarios reflecting assumptions about the conditions expected to exist in the year 2020 had the CVPIA not been adopted. The base-case simulations found that:
- In average water year conditions, gross revenues from crop production totaled $10.2 billion, including net revenues of $371 per acre in the Western San Joaquin and $117 per acre in the Sacramento Valley.
- In dry years, average surface water supplies decline by 20 percent, with net revenues declining by 11 percent in the Western San Joaquin, and 4 percent in the Sacramento Valley.
- In wet year conditions, average surface water supplies increase by 11 percent over average years, but net crop revenues are virtually unchanged from those in average years.
For additional details, see Weinberg, et al., 2002.
Upper Watershed Analyses. To represent the processes occurring in the upper watersheds of the Sacramento River Watershed, above the major reservoirs, we focused on the Clear Lake Watershed. This would enable us to build upon the long-term research program established by the University of California-Davis faculty associated with the Center for Ecological Health Research. We concentrated on two issues: (1) the generation of mercury, and (2) sediment loads to the Clear Lake system. These are two of the most important pollutants in the larger watershed and are very important for management of many local watersheds.
Mercury Contamination. Several subprojects with funding from multiple sources dealt with various aspects of the transport, fate, and impacts of methyl Hg on the aquatic ecosystem of Clear Lake (Suchanek, et al., 1999). Much of our work was directed at understanding the current load of mercury to Clear Lake versus historic loading from waste piles bulldozed into the lake at Sulphur Bank mine from 1927-1957. Our recent studies on acid mine drainage indicate that substantial ongoing discharge from the mine produces a flocculent precipitate near the mine, which, in turn, provides highly favorable conditions for mercury methylation (Suchanek, et al., 2000b). We investigated the historical record of Hg input to Clear Lake (both before and after mining) through a sediment coring project. We collected a new series of deeper cores (about 3 m in length), which were analyzed for total mercury, methylmercury, 210Pb (for dating), and a suite of other parameters. Dramatic changes took place in the core at a depth corresponding to 1927, the date when the Sulphur Bank Mine was first operated as an open pit system. We have collected data to do trophic analysis of mercury with the biotic compartments of Clear Lake. One of the interesting features of the Clear Lake system is that inorganic mercury concentrations are quite high, but methylmercury contamination of the upper ends food chains, where mercury poses a risk to humans and wildlife, is relatively modest.
Sediment Yield. The causes of sediment load produced from upper watersheds into the larger rivers and estuary is poorly understood, mostly because traditional techniques for gauging flows and sediment loads on a scale fine enough to understand processes are exceedingly expensive. We attempted a detailed sediment source sampling program in the Clear Lake/Cache Creek Watershed. The sampling involved surface grab samples and short cores within Clear Lake, and bedload and suspended load samples within the Cache Creek Watershed and its tributaries. Using cluster analysis, we classified source materials into specific categories that are dependent upon their geochemistry and mineralogy. Mass-balance equations, which can be solved simultaneously through weighted linear least squares, were developed to establish and calibrate a mixing model for source areas of sediment.
Progeny: The Consumnes Research Group. One of the overarching goals of this research project was to foster new, innovative approaches to the analysis and management of water resources by linking together faculty and researchers from a broad range of disciplines. Utilizing many of the "lessons learned" from this Sacramento watershed grant, a subset of researchers established a new multidisciplinary research group to focus on monitoring and research needs within the Sacramento and San Joaquin River Watershed. The Cosumnes Research Group program focuses on the linkages between land use, ecosystem attributes, and restoration effectiveness within the Cosumnes and Mokelumne Rivers and the North Delta. Established with seed monies from the Packard Foundation and cooperation from The Nature Conservancy, the group includes more than 34 faculty, research staff, and graduate students from the University of California-Davis and the University of California-Berkeley, and a broad array of agency, stakeholder, and foundation partners. To date, more than $5 million in extramural research funding has been secured for this research project.
GIS Components. The role of this component was primarily to provide a geospatial data infrastructure for modeling efforts in other components and to provide outreach to state and federal watershed protection efforts. Many of the data have been more extensively used in watershed analyses by government programs than by the project itself, but the hydrography and land use data underlie the overall project synthesis.
The Stream Network Base Map. The only hydrography coverage for the whole basin available at the beginning was the Reach File 3 coverage, which had multiple defects for use in defining the network, including discontinuities (streams disappeared and reappeared), streams crossing ridge lines, errors in names, watershed codes, and direction of flow. Records covering approximately one-third of the 100,000 plus kilometers of streams in the basin had some kind of attribute error. We corrected the errors in the basin, and subsequently used the same model to correct records for the rest of the state (and elsewhere).
Impaired Waterbodies. A major driver of watershed management policy in California is the total maximum daily load (TMDL) provisions of Section 303(d) of the Clean Water Act. This analysis was hampered by coarse georeferences (i.e., an entire river may be listed as impaired, when it is only a few lower reaches) and an inability of analysts to easily map sources and results of impairment. We combined the stream network data with the existing 303(d) list and basin plan data to develop a decision support system for Regional Water Quality Control Boards to map impairment data and report it to the state and the U.S. Environmental Protection Agency (EPA). Subsequent funding from the EPA (through the State Water Board), CalTrans, and the North Coast Water Board has been used to develop methods for using both Landsat and airborne hyperspectral to assess the impacts of roadbuilding, forestry operations, and landslides (among other effects) on sedimentation rates.
Riparian Vegetation. Although understanding the locations and condition of riparian vegetation is essential to a number of the modeling efforts (nonpoint source inputs, water temperature and shading, channel stability), no useful map of riparian vegetation existed for the Sacramento Basin. We developed a preliminary map using a mix of local map and imagery sources, and compared existing riparian with areas with riparian-associated soil types. The result was the best documented demonstration of the popular assertion that 95 percent of lowland riparian has been lost (actually closer to 98 percent), and provides a basis to assessing where riparian restoration is likely to be successful (Hunter, et al., 1999). Since that time, we have nearly completed a project, with funding from both CALFED and the Packard Foundation, in the Cosumnes River floodplain to predict conditions (flood dynamics, deposition and soil, land use history, groundwater relations) under which natural restoration of riparian forest is and is not successful when more natural flood regimes are restored, as by levee breaches or levee setbacks. We have shown that successful re-establishment of riparian forests depends heavily on a combination of flood frequency, inundation times, proximity to rivers, and depositional environment (Keller and Quinn, in press).
Aquatic Vertebrates. Although much of the management strategy for the Bay-Delta responds to the dynamics of salmonids and Delta smelt, there are a number of other rare or unusual species in the basin, most of them threatened by modified flows, exotic predators and competitors, and possibly toxic substances. However, at the beginning of the project, the data on locations and population trends of native fish and amphibians was fragmented and mostly not electronic. We developed relatively systematic occurrence databases and maps for the basin and beyond (see http://ice.ucdavis.edu/aquadiv/ Exit ). In particular, we have developed timeseries data to assess the locations and potential causes of amphibian declines (Davidson, et al., in press).
Review of Erosion Models. Given the dearth of information on effects of upland land use on water quality in the valley rivers and delta, we proposed to evaluate watershed-scale sediment yield models as inputs to the hydrological models discussed above. We reviewed a number of published models (e.g., BASINS, AgNPS) for application in headwater watersheds around the Central Valley. In practice, those that can be run without highly detailed landform, climate, and soil data are based on the Universal Soil Loss Equation (USLE). We found that applications of these models to large watersheds required parameter data that is currently unavailable for large areas in any given watershed (e.g. USGS HUC). As more data became available in electronic format for more extensive areas, these more complex models can be applied to larger areas. In the meantime, we developed and tested custom USLE applications in the Clear Lake and Cosumnes watersheds (Keller and Mount, unpublished manuscript), and were able to rank impacts of potential improvements in land practices on sediment yield.
Political Context. The political analysis for this project involves two related studies examining changes over time in the beliefs of San Francisco Bay/Delta water policy participants. The first is a general analysis of the beliefs expressed at administrative and legislative hearings over the period from 1953 to 1996. The second uses elite surveys in 1992 and 1997 to examine whether the December 1994 Bay/Delta Accord led to belief convergence among Bay/Delta policy participants.
The coding project involved coding the content of 552 testimonies presented at 60 legislative and administrative hearings dealing with one or more aspects of Bay/Delta water policy between 1953 and 1996. Among the major findings were the following:
- The overall means on a variety of environment-development scales remained remarkably stable over the 4 decades. The 1970s were no more "environmental" than any other decade.
- There was relatively little concern with overall Bay/Delta water policy. Instead, attention was focused on narrower topics such as fisheries, water supply, water pollution, and fill.
- In every time period, including the 1960s, more concern has been expressed about the welfare of fisheries than any other group. In short, concern with fisheries was not a product of the 1976-77 drought. It has been there since the 1950s, but the relative frequency with which it is discussed has increased over time, particularly in the 1990s.
The second project involved an analysis of belief change among Bay/Delta water policy participants between 1992 (a period of intense conflict over the CVPIA) and 1997 (a couple years after the December 1994 Bay/Delta Accord, which essentially created CALFED and established a set of water quality standards for the Bay Delta). The central question is the extent to which reaching a negotiated settlement after years of intense conflict leads to a convergence of views on a variety of beliefs, including general ideology, perceptions of problem severity and sources, and policy preferences (see Sabatier and Zafonte, 2001). The data are drawn from 465 respondents (55 percent response rate) to the 1992 survey and 672 respondents (44 percent response rate) to the 1997 survey. The analysis of belief change in this paper is restricted to the "panel" of 130 people who responded to both surveys.
We considered belief change on three expressions of general beliefs, two perceptions of the causes of decline in Bay/Delta fisheries (diversions and the Asian clam), and three policy preferences (amend Endangered Species Act (ESA) to allow consideration of economic factors in listing decision, support building of Peripheral Canal/isolated facility, and abolish CVP subsidies. In general, there was very little belief change, either on the overall means for each of the eight items or on the means for nine categories of organizations. We also completed regression analyses of the factors affecting changes on each of the three policy preferences for the130 members of our panel. The most important explanatory variable across the three equations was changes in the general environmentalism scale: the more environmental people became, the more they opposed amending the ESA, the more they opposed the Peripheral Canal, and the more they supported ending CVP subsidies. The causal perceptions regarding the importance of (a) diversions and (b) the Asian clam in explaining fishery declines were significant in at least two of the equations. The importance of different information sources (environmentalists versus water users) did not explain belief change, once changes in other beliefs had been accounted for.
Integrated Analysis of Management Options. The fundamental objective of this large, complex research project was to develop and use a set of interrelated simulation models to conduct a quantitative assessment of several management strategies for restoring the Sacramento watershed ecosystem, particularly with respect to striped bass and winter run salmon. Previous sections of this report have discussed the hydrodynamic, water quality, fishery, and economic models. This section utilizes those models to analyze the implications of two management scenarios in normal and dry years. The two management scenarios are:
- A reallocation of 1.2 million acre-feet of water (800,000 acre-feet in dry years) from irrigated agriculture to fishery purposes, as mandated by the Central Valley Project Improvement Act of 1992. This represents about a 10 percent reallocation of irrigated water in the Central Valley. Because the CVPIA does not specify from where the water is to be reallocated, we examine two sub-scenarios: (1) one in which the water comes from the Sacramento Valley, and (2) the other in which it comes from the Western San Joaquin.
- The construction of an isolated facility-formerly known as the Peripheral Canal, which would divert 5,000-15,000 cfs from the Sacramento River north of the Delta (at Hood), transport it via an aqueduct completely around the eastern edge of the Delta, and deposit the water directly at the South Delta pumps of the State and Federal water projects.
The basic strategy is to use the economic models to determine the most efficient allocation of water reductions across farming regions; then use the hydrodynamic and water quality models to determine the impacts of those diversions on flows and salinity. Finally, we would use the fishery models to predict the impacts on striped bass and winter-run salmon. The temporal scale for all model runs is a month.
Following are the major findings for each of the two management scenarios, starting with the water allocations from the CVPIA:
- In an average water year, taking all the water from the Sacramento region involves a 25 percent reduction in water supplies for that region, the retirement of 141,000 acres (6 percent of total), and a 25 percent reduction in net revenues. In a dry year, there will be 19 percent reductions in water supply and net revenue, and the retirement of 102,000 acres, relative to a dry-year baseline. The losses are particularly concentrated in two regions, dominated by rice and alfalfa production. For the Central Valley as a whole, however, there is only a 3 percent reduction in net revenue from agriculture.
- In average water years, taking all the water from the Western San Joaquin (WSJ) results in a 13 percent reduction in WSJ net revenues and the retirement of 190,000 acres, mostly in cotton. In wet years, the reductions are somewhat higher. For the Valley as a whole; however, net agricultural revenues decline 3-4 percent in these scenarios.
- In dry years, redistributing water from Western San Joaquin agriculture to the San Joaquin River will substantially benefit striped bass in normal years, with somewhat lesser improvements in dry years.
The following are the results of the Isolated Facility (IF) analysis:
- Because the IF will not change water allocations to agriculture, the impacts on agriculture will be minimal (except for gains in reliability, which we did not analyze).
- The IF will have minimal impacts on salinity in the Delta during normal years, but will substantially improve salinity (over the base case) at the South Delta pumps in dry years.
- The IF would cause modest (5-10 percent) reductions in striped bass but very substantial losses (67-99 percent) to winter run salmon, depending upon the estimate of losses at the fish screen at the Hood diversion point.
In sum, the IF represents a relatively clear tradeoff between benefits to south-of-Delta water users (particularly in dry years) and costs to fisheries, particularly salmon. For a more detailed discussion of the analysis of management options, see Weinberg, et al., 2002.
Journal Articles on this Report : 13 Displayed | Download in RIS Format
Other project views: | All 33 publications | 22 publications in selected types | All 17 journal articles |
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Bennett WA, Kimmerer WJ, Burau JR. Plasticity in vertical migration by native and exotic estuarine fishes in a dynamic low-salinity zone. Limnology and Oceanography 2002;47(5):1496-1507. |
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Davidson C, Shaffer HB, Jennings MR. Declines of the California red-legged frog: climate, UV-B, habitat, and pesticides hypotheses. Ecological Applications 2001;11(2):464-479. |
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Davidson C, Shaffer HB, Jennings MR. Spatial tests of the pesticide drift, habitat destruction, UV-B, and climate-change hypotheses for California amphibian declines. Conservation Biology 2002;16(6):1588-1601. |
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Donohoe RM, Yamamoto JT, Ricker KE, Quinn JF. Exposure factor and toxicity data for California wildlife:data availability and sources of uncertainty for ecological risk assessment. Bulletin of Environmental Contamination and Toxicology 2000;64(6):834-841. |
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Draper AJ, Jenkins MW, Kirby KW, Lund JR, Howitt RE. Economic-engineering optimization for California water management. Journal of Water Resources Planning and Management 2003;129(3):155-164. |
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Harrison S, Viers JH, Quinn JF. Climatic and spatial patterns of diversity in the serpentine plants of California. Diversity and Distributions 2000;6(3):153-161. |
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Hunter JC, Willett KB, McCoy MC, Quinn JF, Keller KE. Prospects for preservation and restoration of riparian forests in the Sacramento Valley, California, USA. Environmental Management 1999;24(1):65-75. |
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Jenkins MW, Lund JR, Howitt RE. Using economic loss functions to value urban water scarcity in California. Journal of the American Water Works Association 2003;95(2):58-70. |
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Jenkins MW, Lund JR, Howitt RE, Draper AJ, Msangi SM, Tanaka SK, Ritzema RS, Marques GF. Optimization of California's water supply system: results and insights. Journal of Water Resources Planning and Management-ASCE 2004;130(4):271-280. |
R825285 (Final) |
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Moyle PB, Baxter PB, Sommer T, Foin TC, Matern SA. Biology and population dynamics of Sacramento Splittail (Pogonichthys macrolepidotus) in the San Francisco estuary: a review. San Francisco Estuary and Watershed Science 2004;2(2):Art. 3, 47 pp. |
R825285 (Final) |
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Newlin BD, Jenkins MW, Lund JR, Howitt RE. Southern California water markets: potential and limitations. Journal of Water Resources Planning and Management 2002;128(1):21-32. |
R825285 (Final) |
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Suchanek TH, Mullen LH, Lamphere BA, Richerson PJ, Woodmansee CE, Slotton DG, Harner EJ, Woodward LA. Redistribution of mercury from contaminated lake sediments of Clear Lake, California. Water, Air, and Soil Pollution 1998;104(1-2):77-102. |
R825285 (Final) R825433 (Final) |
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Weinberg M, Lawrence CA, Anderson JD, Randall JR, Botsford LW, Loeb CJ, Takodoro CS, Orlob GT, Sabatier P. Biological and economic implications of Sacramento watershed management options. Journal of the American Water Resources Association 2002;38(2):367-384. |
R825285 (Final) |
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Supplemental Keywords:
water, watersheds, sediments, estuary, health effects, ecological effects, stressor, mercury, pesticides, ecosystem, integrated assessment aquatic, habitat, public policy, decisionmaking, cost benefit, environmental chemistry, biology, engineering, ecology, hydrology, geology, social science, modeling, remote sensing, surveys, circulation models, California, CA, EPA Region 9, agriculture, business, transportation, mining;, RFA, Scientific Discipline, Water, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Water & Watershed, Hydrology, Ecosystem/Assessment/Indicators, Environmental Chemistry, State, Chemistry, Economics, Ecological Effects - Human Health, Ecological Risk Assessment, Watersheds, Mercury, EPA Region, risk assessment, aquatic, fate and transport, Region 9, social impact assessment, stream flows, integrated approach, hydrodynamic water quality model, remote sensing , fisheries, agricultural environment, watershed influences, statistical model, aquatic ecosystems, water quality, ecosystem restoration, water management options, public policy, California (CA)Relevant Websites:
http://watershed.ucdavis.edu/crg/ Exit
http://ice.ucdavis.edu/ Exit
http://my.engr.ucdavis.edu/~wremg/sacbay/sacbay.html Exit
http://cee.engr.ucdavis.edu/faculty/lund/CALVIN Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.