San Francisco Bay

The San Francisco Bay region is 4500 square miles, extending from Tomales Bay in Marin County to southern Santa Clara County and inland to the eastern edge of Suisun Bay. Land use varies from the urban Bay area cities to the Napa and Sonoma Valley wine growing regions and includes significant Pacific Coast marshes as well as Suisun Marsh, the largest contiguous brackish marsh on the West Coast of North America.

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DRERIP Ecosystem Conceptual Model: Riparian vegetation

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

Summary

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.

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DRERIP Ecosystem Conceptual Model: Sacramento splittail

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

Summary

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.

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DRERIP Ecosystem Conceptual Model: White sturgeon

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

Summary

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.

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DRERIP Ecosystem Restoration Model: Tidal marsh

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

Summary

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.

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Drinking Water Notification Levels and Response Levels: An Overview

California State Water Resources Control Board (SWRCB) | February 6th, 2020

Summary

The Division of Drinking Water’s precursor, the Drinking Water Program of the California Department of Public Health (CDPH), and earlier, the California Department of H

The Division of Drinking Water’s precursor, the Drinking Water Program of the California Department of Public Health (CDPH), and earlier, the California Department of Health Services, CDHS, established health-based advisory levels, called “notification levels” (referred to as “action levels" through 2004), as needed since the early 1980s. These have been used to provide information to public water systems and others about certain non-regulated chemicals in drinking water that lack maximum contaminant levels (MCLs). When chemicals are found at concentrations greater than these levels, certain requirement and recommendations apply. Generally, notification levels have been established in response to actual contamination of drinking water supplies, e.g., perchlorate, which now has an MCL. However, notification levels for a number of chemicals were established in anticipation of possible contamination, such as from a hazardous waste site containing many pesticides (in the 1980s), or from a Superfund site (in the 2000s). Chemicals for which notification levels are established may eventually be regulated by MCLs (through a formal regulatory process), depending on the extent of contamination, the levels observed, and the risk to human health. Most, however, have not proceeded to MCLs. Once established, a notification level generally stays in place, unless it is replaced by an MCL.On occasion, though, we have revised the numeric value of an individualnotification level to reflect new risk assessment information on the particularchemical. For some of the chemicals that had advisory levels established early on, if noMCL was adopted and the need for the notification level had passed, the advisory levelwas archived. Archived advisory levels may nevertheless be updated to reflect any newrisk information that may become available, and may be used as notification levels ifneeded. To date, of the 93 chemicals for which notification levels have been established; 40 now have MCLs. Of the remaining 53 chemicals, 29 are chemicals with current notification levels. 24 are chemicals with archived advisory levels (AALs). Note that following adoption of an MCL, the notification level is no longer used. For more about AALs and notification levels, go to: http://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/NotificationLevels.shtml.

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Drought and Equity in the San Francisco Bay Area

Pacific Institute | June 29th, 2016

Summary

California’s ongoing drought has wide-reaching impacts, from how we grow crops to the price of electricity. Often overlooked is its impact on disadvantaged communities.

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Drought and the California Delta—A Matter of Extremes

University of California, Davis (UC Davis) | July 14th, 2014

Summary

California is in an extreme drought as a result of low precipitation in water year 2012, record low precipitation in 2013, and the remarkably dry first few months of 2014

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Drought Contingency Planning (DCP) Negotiation #142, Attachment 1

California Department of Water Resources (DWR) | April 30th, 2020

Summary

This white paper describes current understanding of how the Department of Water Resources (DWR) would account for and administer the Delta Conveyance Facility (DCF) Bene

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Drought less predictable under declining future snowpack

Nature Portfolio (Springer Nature) | April 20th, 2020

Summary

Mountain snowpack serves as an immense natural water reservoir, and knowledge of snow conditions helps predict seasonal water availability and offers critical ear

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Drought Management and Climate Adaptation of Small, Self-Sufficient Drinking Water Systems in California

California Energy Commission (CEC) | August 15th, 2018

Summary

Examining human impacts, responses, and challenges to extreme climatic events can give insight into needed directions for climate adaptation to reduce future risks. This

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San Francisco Bay

DRERIP Ecosystem Conceptual Model: Riparian vegetation

DRERIP Ecosystem Conceptual Model: Sacramento splittail

DRERIP Ecosystem Conceptual Model: White sturgeon

DRERIP Ecosystem Restoration Model: Tidal marsh

Drinking Water Notification Levels and Response Levels: An Overview

Drought and Equity in the San Francisco Bay Area

Drought and the California Delta—A Matter of Extremes

Drought Contingency Planning (DCP) Negotiation #142, Attachment 1

Drought less predictable under declining future snowpack

Drought Management and Climate Adaptation of Small, Self-Sufficient Drinking Water Systems in California

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