DRERIP Ecosystem Conceptual Model: Potamcorbula amurensis

California Department of Fish and Wildlife (CDFW) | ?

Potamocorbula amurensis is a pest in the San Francisco Estuary (hereafter SFE) due to its ability to heavily graze pelagic food resources and its accumulation of toxic su

Potamocorbula amurensis is a pest in the San Francisco Estuary (hereafter SFE) due to its ability to heavily graze pelagic food resources and its accumulation of toxic substances that are then moved into the food web through its predators. We begin by describing what we know of its life history and establish its life cycle within the framework of the ecological setting of the SFE. This model should be used within the context of a thought experiment, as there is not enough known about the species to design a strategy to control it in the SFE or Delta. The ultimate purpose of this conceptual model of Potamocorbula amurensis is to explore its weaknesses. The geographic focus of the DRERIP models is the Delta. However we examine the life history patterns of Potamocorbula amurensis as far down bay as San Pablo Bay for two reasons. First, because some of the largest ecosystem effects attributed to P. amurensis are its consumption of pelagic carbon resources, it is necessary to include areas adjacent to the Delta due to the effects of tidal dispersion. Second, many of the life cycle patterns that are visible in San Pablo Bay are transferrable to upstream locations during drought periods. Finally, we expect this model to evolve as a result of the many ongoing studies on P. amurensis. Some of the data shown in this discussion are the direct result of current CALFED studies being done jointly by California Department of Water Resources (EMP Program D. Messer and K. Gerhts) and the USGS (Analysis of Archived Samples to Assess Patterns of Historic Invasive Bivalve Biomass). Our co-investigators on that study have been gracious in allowing us to show some of that data here, before it has been published. We start the model discussion with a brief description of the taxonomic status of this bivalve because the utility of the literature available to us is based on assumptions of the correct identification. We also very briefly describe its introduction into the SFE as a reminder of the facts about its invasion.

DRERIP Ecosystem Conceptual Model: Pyrethroids

California Department of Fish and Wildlife (CDFW) | February 27th, 2008

To illustrate the applicability of the general model outlined in Delta Chemical Stressors conceptual model Werner et al. (2008), we are providing an example of its implem

To illustrate the applicability of the general model outlined in Delta Chemical Stressors conceptual model Werner et al. (2008), we are providing an example of its implementation for a specific group of contaminants, synthetic pyrethroid insecticides.  Although numerous different pyrethroids exist, the members of this group share many chemical and toxicological characteristics. The US EPA’s decision to phase out certain uses of organophosphate insecticides because of their potential for causing toxicity in humans has led to their gradual replacement by pyrethroids, a class of synthetic insecticides applied in both urban and agricultural areas. They are applied in urban areas primarily for structural pest control, in agricultural areas on crops such as almonds, alfalfa, cotton, lettuce, pistachios, and peaches, and in the home in pet sprays and shampoos. In 2005, five pyrethroids were among the top 21 agricultural insecticides by acres treated in California: lambdacyhalothrin (rank 7), permethrin (rank 9), esfenvalerate (rank 11), cypermethrin (rank 14) and cyfluthrin (rank 21) (California Department of Pesticide Regulation, Pesticide Use Reporting database: www.cdpr.ca.gov). Both winter storm runoff, as well as irrigation return water may be important routes of transport into aquatic systems. Pyrethroids at toxic concentrations have been detected in the majority of sediment samples collected from water bodies draining agricultural areas in the Central Valley (Weston et al., 2004; California Regional Water Quality Control Board Agricultural Waiver Program, 2007), as well as from urban creeks in the Bay/Delta region (Amweg et al., 2006; Woudneh and Oros, 2006 a, b). Pyrethroid concentrations toxic to aquatic life were detected in water samples from Central Valley agricultural drains and creeks (Central Valley Regional Water Quality Control Board, 2005; Bacey et al., 2005), and tributaries to San Francisco Bay (Woudneh and Oros, 2006 a, b). Aquatic organisms, in particular insects, crustaceans and fish, are highly sensitive to pyrethroid insecticides (Oros and Werner, 2005). Acute toxicity to fish and aquatic invertebrates is generally observed at concentrations below 1 ?g/L, and sublethal effects have been reported at low ng/L concentrations. Although it is difficult to model sublethal responses to toxicants and predict ecotoxicological impact or risk, measures of sublethal effects are likely to be as important, or more important, than the measures of acute or chronic lethal effects to accurately assess the consequences of contaminant exposure. All pyrethroids are potent neurotoxicants (Bradbury and Coats, 1989; Shafer and Meyer, 2004), can inhibit ATPases (Litchfield, 1985), and have immunosuppressive effects (Madsen et al., 1996; Clifford et al., 2005). In addition, these compounds and their breakdown products can disrupt hormone-related functions (Go et al., 1999; Tyler et al., 2000; Perry et al., 2006; Sun et al., 2007). As pyrethroid concentrations in the Delta would be expected to peak during the winter/spring storm season (Werner et al. 2004, 2006), as well as after peak agricultural application in the summer and fall (Weston et al., 2004), early life-stages of important Delta fish species or their prey may be directly exposed to these contaminants. The storm season coincides with the spawning and rearing period of several important fish such as the delta smelt, which spawns from February to June (Moyle, 1976). Juvenile fish depend on planktonic crustaceans, small insect larvae, and mysid shrimp as their major food items (Moyle 1976), which are highly sensitive to pyrethroids. It has been suggested that urban and agricultural pesticide use in the Central Valley and Delta region might play a role in the pelagic organism declines observed in the upper estuary (Oros and Werner, 2005).

DRERIP Ecosystem Conceptual Model: Riparian vegetation

California Department of Fish and Wildlife (CDFW) | November 14th, 2008

The Sacramento-San Joaquin Delta has immense municipal, agricultural, biological and industrial importance to the economy and livelihood of California and in turn to the

The Sacramento-San Joaquin Delta has immense municipal, agricultural, biological and industrial importance to the economy and livelihood of California and in turn to the United States. Plans to improve conditions in the Delta must address both human and biological communities. The region has been altered extensively over the past 200 years from land conversion to agriculture, fluxes in sedimentation rates, levee construction, and a completely re-plumbed network of waterways and hydrology (Thompson, 1957). Remnant, native riparian and wetland plant communities are almost completely removed and there is some question of whether the natural processes that create and maintain them can be restored (Mount and Twiss, 2005). Restoration implementation will be difficult considering the extent of alteration and complexity of both the natural system and cultural setting. The scientific approach to resolve these issues needs to reflect system complexity and represent the many potential response pathways that lead from proposed alterations. Development of conceptual models to understand these potential pathways is an important first step in understanding restoration implementation (and other management actions) in light of the complexity of the natural system and existing management scheme. The CALFED program is interested in restoring the Delta ecosystem to the extent possible. Riparian Vegetation (RV2) is but one of the natural systems of interest; others include fisheries, wildlife, and other plant communities. The conceptual model presented here deals exclusively with those physical, chemical, and ecological processes relevant to riparian vegetation. Riparian vegetation is important not only for biological conservation of the plant species themselves, but also the other flora and fauna species—and the physical and ecological processes—that depend upon riparian vegetation. Although the restoration of riparian vegetation as a component of a healthy riverine landscape has cultural and economic importance, these aspects are not included in this model. The conceptual model of riparian vegetation presented here is actually a sub-model of the larger floodplain processes/habitat model (Figure 1). The RV Sub-model is general by design, and is intended to provide a framework for potential expansion or adaptation to more-refined models of individual species, habitats, and/or entire landscapes. Spatially, we focus specifically on the floodplain or land area beginning at the upper edge of the emergent vegetation zone, then moving up in elevation and inland from the water, ending when non-floodplain areas, open water, or marsh is encountered. Together, the Floodplain model and the RV Sub-model can be used to analyze various “scenarios,” ranging from potential restoration or research actions, to water management decisions, to placement of bank protection at a specific Delta levee site. In addition, to highlight key differences in conditions that occur in the Delta, we present here two specific applications of the RV Sub-model that we generalize as a being dominated by tidal processes and another dominated by more riverine processes.

DRERIP Ecosystem Conceptual Model: Sacramento splittail

California Department of Fish and Wildlife (CDFW) | September 3rd, 2008

Model has not yet fully completed the peer review and collegial review process and final modifications may be required of the developers. Model may not be cited or circul

Model has not yet fully completed the peer review and collegial review process and final modifications may be required of the developers. Model may not be cited or circulated until that process is complete. It may be used in identifying and evaluating restoration actions with assistance from content experts. Model is appropriate for use by experienced evaluation team with input from content experts as necessary. The purpose of this conceptual model is to aid management decisions for the continued persistence and recovery of Sacramento splittail. This model, along with the suite of models developed through ERP as well as other information and tools, is intended to be used for evaluating proposed restoration actions for the Delta and throughout the species geographic range. It is a qualitative life-cycle conceptual model that attempts to bring together many sources of information to build a comprehensive document that represents the current state of knowledge for the species. It is not a quantitative model however. It will not provide quantitative limits on species take or population number outcomes. It will only provide an indication of anticipated population response (i.e. increase or decrease with a magnitude of x or y) based on the most current scientific knowledge. With this knowledge, proposed restoration actions can be grouped and a positive population response can be developed through an adaptive management framework. The model must be read and understood in its entirety and does not provide users/readers quick solutions or answers. The entire life-cycle of the animal must be understood by decision makers if they intend to make sound choices in the future. The conceptual model diagram and associated tables can be used to focus the reader on potential species and population limiting factors given the current scientific understanding under current conditions. The model has a specific emphasis on the Delta; however the entire species range must be considered when population level responses are of concern. For this reason the geographic scope of this document is beyond the legal boundaries of the “Delta”. This is not intended to be the final version of this conceptual model. As new information becomes available through research and in the scientific literature, this model will be updated as time allows providing managers with the most current information available. This conceptual model relies heavily on the extensive work done by Peter Moyle and others in their 2004 white paper Biology and Population Dynamics of Sacramento Splittail (Pogonichthys macrolepidotus) in the San Francisco Estuary: A Review which was published in the San Francisco Estuary and Watershed Science online journal. Content in the model is taken from that review unless otherwise indicated. These sections will be introduced with a citation to Moyle et al. 2004. This model also takes into account new research on Sacramento splittail which has occurred subsequent to the white paper.

DRERIP Ecosystem Conceptual Model: Sedimentation

California Department of Fish and Wildlife (CDFW) | November 13th, 2007

1) Sediment supply: The supply of sediment from the watershed to the Delta is limited.  Sediment supply is decreasing due to trapping behind dams and diminishment of the

1) Sediment supply: The supply of sediment from the watershed to the Delta is limited.  Sediment supply is decreasing due to trapping behind dams and diminishment of the hydraulic mining sediment pulse. 2) Sustainability: The Delta is depositional and adequate sediment deposition is required for wetlands to keep up with sea level rise. 3) Restoration: Typical suspended-sediment concentrations in the Delta range from 10-50 mg/L except during river floods when it can exceed 200 mg/L. Natural wetland sedimentation when concentration is 100 mg/L is about 0.025 m/yr, so deposition rates in the Delta are smaller. 4) Light and biota: Suspended sediment is the primary attenuator of sunlight in the water column of the Delta. Photosynthesis, primary production, and fish behavior depend on light. 5) Model uncertainty: Physical processes are qualitatively understood but difficult to quantify. Erosion is more difficult to quantify than deposition. Biological processes that affect sedimentation are not as well understood qualitatively and are very difficult to predict quantitatively. Outcomes The four primary outcomes of this conceptual model are: 1) Bed sediment character (size, organic content) 2) Geomorphic change 3) Suspended sediment character (concentration, organic content, settling velocity) 4) Water column light These outcomes are used by habitat, stressor, and species models. The first three outcomes are also drivers in this model because of feedback loops. This conceptual model also has many intermediate outcomes that are used as drivers in the model and are available to other models.

DRERIP Ecosystem Conceptual Model: White sturgeon

California Department of Fish and Wildlife (CDFW) | April 25th, 2011

The purpose of this report is to develop a conceptual life history model of white sturgeon (Acipenser transmontanus) and the factors that affect reproduction, growth, and

The purpose of this report is to develop a conceptual life history model of white sturgeon (Acipenser transmontanus) and the factors that affect reproduction, growth, and survival in the Sacramento-San Joaquin Rivers and San Francisco bay-delta. This model can be used to organize, visualize, and evaluate how the complex life history of white sturgeon relates to the spatial and temporal variability of riverine and estuarine ecosystems and potential consequences of ecosystem restoration and water management alternatives. This model is compatible with the suite of environmental and species models developed by the Department of Fish and Game Ecosystem Restoration Program (ERP) to assess and prioritize proposed restoration actions for the delta. The model has a geographic emphasis on the Sacramento River and bay-delta regions, though the entire distribution of white sturgeon should be considered when population level responses are of concern, due to the migratory life history of this species. The conceptual life history model incorporates information from numerous sources about white sturgeon, often relying upon life history information from populations outside California. While additional surrogate information from other North American sturgeons could have been used in the model, the distinctive diadromous and ecological characteristics of California white sturgeon limited the utility of these species’ information, thus information from other diadromous sturgeon species is only occasionally considered. Due to the limits of quantitative information about white sturgeon, this model is presented in a qualitative narrative, though numerical information is provided when available. While it will not provide quantitative limits on species take relative to maintaining a stable population size, it could be further developed into a population forecasting model since it divides the life history into life history stages, transition probabilities, and factors whose effects on reproduction and survival could be quantified. Life history stage transitions are visualized in a series of life stage submodels highlighting the processes and relationships among ecological factors influencing the transition between stages (Figures 1 and 2). A complex set of conditions and processes are necessary to determine whether an individual white sturgeon completes the transition from one life stage to the next. Our knowledge of how biotic and abiotic factors are critical for maintaining healthy populations is fairly basic. Thus, the importance, predictability, and understanding of each of these linkages are identified in the model. Lastly, a similar characterization of independent stressors is undertaken to describe potential factors affecting survival during each life history stage in a known geographic region. This model is dynamic and not intended to be a final version. As new data become available, the model should be refined so managers and biologists have the most current information available.

DRERIP Ecosystem Restoration Model: Tidal marsh

California Department of Fish and Wildlife (CDFW) | October 1st, 2008

Tidal marshes are a subset of estuarine wetlands defined by the presence of emergent vegetation types uniquely adapted to sheltered intertidal zones of temperate and subt

Tidal marshes are a subset of estuarine wetlands defined by the presence of emergent vegetation types uniquely adapted to sheltered intertidal zones of temperate and subtropical coastal plains (Chapman 1960, 1976, Mitsch & Gosselink 1993). They are found across a full range of salinity conditions from seawater on the immediate coast to freshwater tidal reaches of estuarine river systems. Marshes are transitional ecosystems that provide critical connections between adjacent subtidal and terrestrial ecosystems within the estuarine landscape (Simenstad et al. 2000; Levin et al. 2001). These “critical transition zones” often function as conduits for substantial fluxes of materials and energy (Ewel et al. 2001), and provide a variety of valuable ecosystems functions, goods and services related to the maintenance of biodiversity, fish and wildlife habitat, water quality, flood abatement and carbon sequestration (Rabenhorst 1995, Costanza et al. 1997, Weslawski et al. 2004, Zedler & Kercher 2005). However, estuarine marshes and the biotic communities that depend on them are vulnerable to both direct and indirect anthropogenic impacts (Holland et al. 2004, Snelgrove et al. 2004), and the functionality of these systems can be difficult to restore once severely impacted (Zedler & Kercher 2005). The San Francisco Bay and Sacramento-San Joaquin River Delta estuary is perhaps the most hydrologically-engineered estuarine wetland system in the United States, and an estimated 95% of the marsh area that existed there in 1850 has been altered or converted to other land uses (Josselyn 1983). The principal source of freshwater input to the estuary enters through the Sacramento and San Joaquin rivers; their inland delta (the Delta) is the terminus of a watershed that drains about 40% of California’s land area. Anthropogenic alterations of the estuary’s hydrologic characteristics have profoundly affected the extent and functioning of the tidal wetlands, particularly in the brackish and tidal fresh portions of the upper estuary associated with the Delta. Although the conceptual model presented in Figure 1 is intended to capture the features and dynamics of tidal marshes in the Delta (e.g., Suisun Bay to the upriver extent of the tides in the Delta), oligohaline and tidal freshwater marshes generally remain poorly understood. Recent texts (e.g., Sharitz & Pennings 2006) still consider the review by Odum (1988) as the best treatment of these low salinity tidal ecosystems. Consequently, development of the current conceptual biological model often required us to judiciously borrow from the more extensive literature on temperate salt marshes in diverse regions. Although one of our principal objectives in developing this model involves identifying the dominant processes and interactions that characterize restoring marshes at various stages of development, the model is intended to characterize the dynamics of “equilibrium” marshes at their mature state of geomorphic and ecological functioning (Pestrong 1972, Reed 2002, Williams et al. 2002). Our rationale is that restoring marshes are considerably variable and that trying to capture intermediate stages of development (e.g., positions along a development “trajectory”; Simenstad & Thom 1996 [however, see Zedler & Callaway 1999]) would introduce too much variability for a single model, and because the ultimate objective of restoration is the self-sustaining, equilibrium condition. However, we have sought were appropriate to describe important processes that influence restoration trajectories and affect the ecosystem functions, goods and services that marshes provide in various landscape settings that are found in the Sacramento-San Joaquin Delta.

Drift of Earth's Pole Confirms Groundwater Depletion as a Significant Contributor to Global Sea Level Rise 1993–2010

American Geophysical Union (AGU) | June 15th, 2023

Drinking Fountains and Public Health: Improving National Water Infrastructure to Rebuild Trust and Ensure Access

Pacific Institute | February 27th, 2017

Public drinking fountains are disappearing across the U.S., yet many people – including children, commuters, joggers, tourists, and the homeless – rely on them for ch

Public drinking fountains are disappearing across the U.S., yet many people – including children, commuters, joggers, tourists, and the homeless – rely on them for cheap, accessible, and safe municipal water. Concerns over drinking water quality and possible disease transmission as well as widely-publicized water contamination incidents are both contributing factors in the decline. Are drinking fountains truly a cause of illness? What would it take to rebuild public trust in this important water infrastructure so drinking fountains can continue to be a safe, accessible resource for those who rely on them? In this Pacific Institute report, the authors examine epidemiology studies and other evidence of drinking fountain-related health issues. They find limited evidence of a causal relationship between illness and the use of drinking fountains. Further, problems that were identified can be traced to contamination from poor cleaning and maintenance or from old water infrastructure in buildings, rather than contamination at the point of use, and these problems can be fixed.

Drinking Water and Exclusion: A Case Study from California's Central Valley

California Law Review | February 1st, 2012

The American West is notorious for its water wars, and California's complex water allocation and governance challenges serve as a bellwether for contemporary water gove

The American West is notorious for its water wars, and California's complex water allocation and governance challenges serve as a bellwether for contemporary water governance across western states, Policy makers and environmental advocates typically represent California's water woes as a regulatory problem - a failure to balance the needs of growing urban populations with ecological preservation and agricultural irrigation. These debates, however, often elide the issue of water deprivation, and they do not adequately address the concerns of an important constituency: low-income, rural communities. This Comment argues that a focus on regulation misses a fundamental feature of water inequality: the structure and design of local water districts. Utilizing a case study of California's Central Valley to illustrate how these structural barriers operate, I argue that Calfornia's complex system of local water districts fractures governance, limits electoral participation, and undermines the State's stated environmental, equity, and utilitarian water goals. I offer suggestions for alternative local water district organization in order to address the constraints of Calfornia's current water governance regime.