Critical Assessment of the Delta Smelt Population in the San Francisco Estuary, California

University of California, Davis (UC Davis) | July 1st, 2005

CVFPP Conservation Strategy Appendix C. Description of Construction Activities for Structural Modifications

California Department of Water Resources (DWR) | July 14th, 2016

This appendix [to the CVFPP Conservation Strategy] provides a general description of construction activities, focused on levee construction. It is based on the Program En

This appendix [to the CVFPP Conservation Strategy] provides a general description of construction activities, focused on levee construction. It is based on the Program Environmental Impact Report (PEIR) for the 2012 Central Valley Flood Protection Plan (CVFPP) (California Department of Water Resources [DWR] 2012). 

CVFPP Conservation Strategy Appendix D. Vegetation Management Strategy

California Department of Water Resources (DWR) | August 17th, 2017

When the 2012 Central Valley Flood Protection Plan (2012 CVFPP) and Conservation Framework were adopted by the Central Valley Flood Protection Board (CVFPB), the CVFPB co

When the 2012 Central Valley Flood Protection Plan (2012 CVFPP) and Conservation Framework were adopted by the Central Valley Flood Protection Board (CVFPB), the CVFPB considered the levee vegetation management strategy contained in the 2012 CVFPP as interim. CVFPB Resolution No. 2012-25 directed the California Department of Water Resources (DWR) to further develop the interim strategy into a more comprehensive approach. Resolution No. 2012-25 further directed that the approach be adaptive and responsive to the results of ongoing and future research regarding vegetation on levees, knowledge gained from levee performance during high-water events, and the need to conserve critical riparian habitat. The DWR vegetation management approach described in this appendix reflects efforts to develop a more comprehensive levee vegetation management strategy that consists of efforts to manage levee vegetation, channel vegetation, and invasive plants. Levee vegetation management is particularly important because levee vegetation can impede visibility and accessibility for inspections and flood fighting, and in some limited cases, it may pose an unacceptable threat to levee integrity. In channel areas in between State Plan of Flood Control (SPFC) levees, the floodplain and channel may provide opportunities for important riparian and wetland habitat, as well as agricultural operations. However, land uses in these areas also need to be managed to maintain the channel’s ability to convey high flows during flood events. Finally, invasive plants can adversely affect operations and maintenance (O&M) of the SPFC and are a documented stressor on the species, habitats, and ecosystem processes targeted by this Conservation Strategy. Management of invasive species, and eradication of them where feasible, reduces O&M needs by increasing channel capacity and provides important ecosystem benefits.  DWR water resources managers have been implementing the interim strategy to balance public safety with environmental quality. Current and future work will focus on improving public safety by providing for integrity, visibility, and accessibility for inspections, maintenance, and flood fight operations; at the same time, protecting important and critical environmental resources. DWR’s approach also includes ongoing policy discussions regarding potential compatibility with United States Army Corps of Engineers (USACE) levee vegetation guidance through recognition of regional variations and prioritization of levee remediation based on risk assessment. Retaining lower waterside vegetation is a leading example of how risk assessment is coupled with recognition that widespread loss of habitat on levees, particularly on the lower waterside slope, is unmitigable. The Conservation Framework identified roughly two-thirds of the riparian habitat that occurs on SPFC levees is found on the lower waterside slope. On-going DWR analyses are further evaluating this assumption. In addition, risk assessment has shown that removing this vegetation, and conducting required levee remediation, likely would not be a worthwhile investment of flood risk reduction dollars. On the contrary, vegetation in this area has long been recognized as offering protection to levees from wind and wave wash erosion (USACE 1955). Expending resources to address factors contributing to lower risk would have to be considered against expending these resources to address other levee conditions that pose a significantly higher risk (DWR 2011). Similarly, DWR is assessing how to identify trees that may pose an unacceptable risk to levee integrity in a manner that retains the majority of existing habitat over its normal life span. Ongoing research, as well as knowledge gained from levee performance during high water events, will continue to inform how vegetation management within and around the SPFC may continue to evolve toward meeting multiple objectives, including sustainability of critical environmental resources. DWR anticipates revising vegetation management policy and guidance as needed in the ongoing five year updates to the CVFPP. 

CVFPP Conservation Strategy Appendix E. Invasive Plant Management Plan

California Department of Water Resources (DWR) | July 14th, 2016

The California Department of Water Resources (DWR) developed this Invasive Plant Management Plan (or Plan) as part of the Conservation Strategy of the Central Valley Floo

The California Department of Water Resources (DWR) developed this Invasive Plant Management Plan (or Plan) as part of the Conservation Strategy of the Central Valley Flood Protection Plan (CVFPP). The Conservation Strategy tiers from the Conservation Framework, which was an integral part of the State’s preferred SSIA, identified in the 2012 CVFPP. The Conservation Strategy describes how to make progress toward meeting the environmental objectives of the Central Valley Flood Protection Act of 2008 (Act) and related legislation throughout the flood management system in the Systemwide Planning Area (SPA). The SPA comprises five Conservation Planning Areas (CPAs) in California’s Central Valley: the Feather River CPA, the Upper and Lower Sacramento River CPAs, and the Upper and Lower San Joaquin River CPAs (Figure 1-1). The SSIA includes developing and implementing multipurpose projects, and this Plan will guide the invasive plant management approaches undertaken as part of these projects.  The Conservation Strategy recognizes invasive plants as a primary stressor on the habitats, species, and ecosystem processes that are the focus of conservation planning. As of 2014, at least 68 plant species considered to be invasive by the California Invasive Plant Council (Cal-IPC) potentially occur in upland, riparian, wetland, and open water habitats in the Sacramento and San Joaquin Valleys (Cal-IPC 2013a). Many are widespread and abundant in vegetation managed as part of State Plan of Flood Control (SPFC) operation and maintenance (O&M). These species degrade riverine and floodplain habitats by altering ecosystem processes and displacing native plants. In addition, some of these invasive species, such as tamarisk (or saltcedar) (Tamarix spp.), giant reed (Arundo donax), and red sesbania (Sesbania punicea), are stressors that increase the cost and difficulty of operating and maintaining the SPFC.  These species can alter hydrology and sedimentation rates in riparian and aquatic systems (Cal-IPC 2011a) and can degrade flood system effectiveness. Importantly, recent studies have shown that certain invasive plant species have greater impacts on channel conveyance than native species adapted to the same areas (Stone et al. 2013). Dense stands of certain invasive species can alter channel morphology by retaining sediments and increasing the hydraulic roughness of the channel, which restricts flows and reduces flood conveyance (Bossard et al. 2000). For example, saltcedar traps and stabilizes alluvial sediments, narrowing stream channels and contributing to more frequent flooding (Bossard et al. 2000). Species with shallow root systems, such as giant reed and red sesbania, promote bank undercutting, collapse, and erosion (Bossard et al. 2000; Cal-IPC 2011b). Invasive terrestrial plants can reduce groundwater availability by transpiring large amounts of water, leaving less water available for native riparian vegetation (Bossard et al. 2000).  Invasive plants can also reduce the integrity of native riparian plant communities by outcompeting native plants, reducing habitat quality and food supply for wildlife, and interfering with wildlife management (Bossard et al. 2000; Cal-IPC 2011a). Nationally, invasive species are the second greatest threat to endangered species, after habitat destruction (Cal-IPC 2011a), and approximately 42 percent of the species listed as threatened or endangered by the federal Endangered Species Act (ESA) are at risk primarily because of the adverse effects of invasive species (Pimentel et al. 2005). Aquatic invasive plants can degrade aquatic habitat by reducing areas of open water used by waterfowl for resting, by shading out algae in the water column and thereby diminishing the basis of the aquatic food web, and by displacing native aquatic plants that are used for food or shelter by wildlife (Bossard et al. 2000). In addition, invasive aquatic plants often form dense mats that kill fish by lowering pH, dissolved oxygen, and light levels and by increasing carbon dioxide and turbidity (Bossard et al. 2000).  Because of these adverse effects and the threats they pose to achieving the goals of the Conservation Strategy, this Plan is driven by the following vision: to reduce the impact of invasive plants as a stressor on conservation targets and as an impediment to the operation and maintenance of the State Plan of Flood Control.  This Plan seeks to increase DWR institutional support for an SPA-wide invasive plant treatment program, and facilitate consistent invasive vegetation treatment actions by levee maintaining agencies and other partners such as the California Department of Fish and Wildlife and the United States Fish and Wildlife Service who are also conducting invasive plant control efforts. SPA-wide implementation of invasive plant treatment faces challenges that include ever-decreasing O&M budgets, regulatory requirements to protect sensitive resources, and the need to meet multiple and sometimes conflicting management objectives. This Plan recognizes those challenges, but it is beyond the scope of a single plan to resolve them all. Instead, the Plan provides first steps toward addressing the challenges through a series of goals, objectives, and implementation actions. The Plan includes measurable objectives for the treatment of four target species (Initial Priority Species) in Channel Maintenance Areas within the SPA (Channel Maintenance Areas; Figure 1-2) and identified in the DWR State Plan of Flood Control Descriptive Document (DWR 2010). It is the intent of this Plan to increase the resources available for invasive plant treatment actions by fashioning an approach that meets multiple needs and, therefore, may take advantage of funding sources not previously available for these actions. 

CVFPP Conservation Strategy Appendix F. Existing Conditions

California Department of Water Resources (DWR) | July 14th, 2016

This appendix describes the existing conditions for the targets of the Central Valley Flood Protection Plan (CVFPP) Conservation Strategy (Conservation Strategy). It desc

This appendix describes the existing conditions for the targets of the Central Valley Flood Protection Plan (CVFPP) Conservation Strategy (Conservation Strategy). It describes these existing conditions for the same geographic units used in the objectives of the Conservation Strategy: conservation planning areas (CPAs) and landscape units within CPAs. 

CVFPP Conservation Strategy Appendix G. Identification of Target Species and Focused Conservation Plans

California Department of Water Resources (DWR) | July 14th, 2016

 The purpose of the Conservation Strategy of the Central Valley Flood Protection Plan (CVFPP) is to provide direction for the California Department of Water Resources’

 The purpose of the Conservation Strategy of the Central Valley Flood Protection Plan (CVFPP) is to provide direction for the California Department of Water Resources’ (DWR’s) environmental stewardship activities related to integrated flood management in the Central Valley, and to provide a framework and support for programmatic permitting of flood management activities.  One goal of the Conservation Strategy is to contribute to the recovery and stability of native species populations and overall biotic community diversity. A set of potential target species was identified to support measurable objectives for this goal. For those target species with the greatest need for recovery of their populations, focused conservation planning was conducted. This appendix documents the process used for selecting the target species of the Conservation Strategy, including 17 target species for which focused conservation planning was conducted. The results of this focused planning are also provided in this appendix, in the form of focused conservation plans. This document is scheduled to be updated every 5 years.   Because the conservation needs of species change, in the future, additional species may become suitable targets for the Conservation Strategy. Therefore, during preparation of the 5-year updates to the CVFPP, the preliminary list of species in this appendix will be reevaluated using the same criteria described below. Species meeting these criteria will be added, and focused conservation plans will be developed for them and included in subsequent updates of the Conservation Strategy. During the public comment period, new information regarding the status of the delta smelt (Hypomesus transpacificus) and its habitat use in the Systemwide Planning Area (SPA) was made available, and a recovery plan for the species is expected to be released in 2016; therefore, this species will be considered for inclusion in the 2022 CVFPP and Conservation Strategy. Other species that were considered during the initial screening could be reconsidered, and targeted conservation plans may be developed. These species include the western pond turtle (Actinemys marmorata), tricolored blackbird (Agelaius tricolor), western red bat (Lasiurus blossevillii), and western burrowing owl (Athene cunicularia hypugaea). 

CVPIA 10 Years of Progress

U.S. Bureau of Reclamation (USBR) | June 27th, 2015

In 1992, Congress passed the Central Valley Project Improvement Act (Act, or CVPIA), which amended previous authorizations of the California Central Valley Project (CVP)

In 1992, Congress passed the Central Valley Project Improvement Act (Act, or CVPIA), which amended previous authorizations of the California Central Valley Project (CVP) to include fish and wildlife protection, restoration, enhancement, and mitigation as project purposes having equal priority with power generation, and irrigation and domestic water uses. Congress directed the Secretary of the Interior, through the Bureau of Reclamation (Reclamation) and the U.S. Fish and Wildlife Service (Service), to operate the CVP consistent with the purposes of the Act, to meet the Federal trust responsibilities to protect the fishery resources of affected Federally recognized Indian tribes, and to achieve a reasonable balance among competing demands for use of CVP water. For the past 10 years, Reclamation and the Service, working together to implement the CVPIA, have embarked on one of the Nation’s largest fish and wildlife restoration efforts. Reclamation and the Service have developed programs to improve environmental conditions and modify operations, management, and physical facilities, and thus, the associated environmental conditions of the CVP to comply with the purposes and goals of the Act. All of the Act’s restoration measures are planned and implemented by Reclamation and the Service and coordinated with the State of California, CALFED, and other partners. In the following pages, you will find a summary of the protection, restoration, enhancement, and mitigation measures that have been implemented as of the end of fiscal year 2002, demonstrating the contributions Reclamation and the Service have made to the Central Valley. As you read the summary, it should become clear that progress is being made in unprecedented programs, and advancements have been made in resolving complicated watershed issues throughout the Central Valley. Yet much work lies ahead.

Dam effects on bedload transport on the upper Santa Ana River, California, and implications for native fish habitat

River Research and Applications (Wiley) | May 23rd, 2019

Dams disrupt the flow of water and sediment and thus have the potential to affect the downstream geomorphic characteristics of a river. Though there are some well‐known

Dams disrupt the flow of water and sediment and thus have the potential to affect the downstream geomorphic characteristics of a river. Though there are some well‐known and common geomorphic responses to dams, such as bed armouring, the response downstream from any particular dam is dependent on local conditions. Herein, we investigate the response of the upper Santa Ana River in southern California, USA, to the construction of a large dam at the transition from mountains to valley, using calculations of bedload transport capacity on the mainstem below the dam and for major tributaries. Approximate sediment budgets were constructed for downstream reaches to estimate deposition and erosion rates for sand, gravel, and cobble particle sizes. Our results indicate that the classical response of bed armouring and erosion is likely limited to a short reach immediately below the dam. Farther downstream, though transport capacity is reduced by flow regulation by the dam, the channel reaches are likely to remain depositional but with reduced deposition rates. Persistent deposition, as opposed to erosion, is the result of the replenishment of flow and sediment supply by large downstream tributaries. In addition, the calculations indicate that the composition of the bed is unlikely to change substantially in downstream reaches. A Monte Carlo approach was employed to estimate the uncertainty in the sediment budget predictions. The impacts of the dam on the geomorphic character of the river downstream could have implications for native fish that rely on coarse substrate that supports their food base.

Dealing with the Delta: Envisioning Futures, Finding Solutions (Research Brief)

Public Policy Institute of California (PPIC) | February 15th, 2007

This research brief summarizes a report by Jay Lund, Ellen Hanak, William Fleenor, Richard Howitt, Jeffrey Mount, and Peter Moyle, Envisioning Futures for the Sacramento�

This research brief summarizes a report by Jay Lund, Ellen Hanak, William Fleenor, Richard Howitt, Jeffrey Mount, and Peter Moyle, Envisioning Futures for the Sacramento–San Joaquin Delta.

Decision Scaling Evaluation of Climate Risks to the State Water Project

California Department of Water Resources (DWR) | May 29th, 2019

This Final Decision Scaling Vulnerability Assessment Report updates and describes a joint endeavor of the California Department of Water Resources (DWR) and the Universit

This Final Decision Scaling Vulnerability Assessment Report updates and describes a joint endeavor of the California Department of Water Resources (DWR) and the University of Massachusetts, Amherst (UMass) to improve planning for the uncertain effects of climate change on the California Central Valley Water System (CVS)1 by integrating vulnerability-based analysis with traditional risk-based assessment methods. This report summarizes the research goals, analytical approach, workflow of modeling tools, evaluation of alternative experimental designs, refined strategy for data visualization, and assessment of the vulnerability of the CVS to climate change.  This report begins with a review of historical and projected climate change in California, which includes descriptions of several DWR-UMass team investigations of historical records, observed climate trends, and many climate projections for the CVS, specifically. The next section of this report summarizes the work previously accomplished by the academic community, the government, and the community of water resources practitioners evaluating climate change-related risks to the CVS.  With that background in place, this report explains the methodology developed for this study (illustrated in Figure ES1) and provides details on each sub-step of the process. Whereas previous studies have tested the response of some aspect of the California water system to ahistorical climate traces, the decision scaling approach adopted for this study allows systematic assessment of the vulnerability of the entire (interconnected and complex) CVS to a wide range of potential future climate conditions, and quantification of the significance of climate shift relative to natural (and climate-change-amplified) variability. The climate response function that results from the decision scaling approach depicts expected water system performance relative to historical performance across a range of climate changes. An important benefit of this approach is the ability to use a variety of climate information sources to assess the level of concern to assign to the vulnerabilities that are identified. Consequently, climate information, including climate change projections and formal probability estimates, can be used as a sensitivity factor when assessing risk, rather than the driver of the analysis. This allows discussion of risk and opportunity (each a function of impact and likelihood) in water system investment.  This assessment of long-term and persistent hydrologic impacts of climate change focuses on the effects to the operation of the State Water Project (SWP), including ecological conditions that dictate operating rules. DWR owns and operates the SWP for flood control, maintenance of environmental and water quality conditions, water supply, hydropower, and recreation. Consequently, analysis of SWP performance under climate-changed conditions yields an array of impact metrics across these areas of concern. The analysis focuses on persistent medium- and long-term conditions evaluated at a monthly time-step. Short-duration extreme precipitation events that cause flooding may also stress water resource management but are beyond the scope of this study.  This study has adopted CalLite 3.0 to simulate the coordinated operations of the Central Valley Project (CVP) and SWP under a wide range of climate possibilities. Climate traces are developed through coupling historical daily temperature and precipitation (1950–2013) (Livneh et al. 2013) to the paleo-dendrochronological reconstructed streamflow record of the Sacramento-4-river annual streamflow (900–2013) (Meko et al. 2014). An advanced hydrologic model, the Sacramento Soil Moisture Accounting distributed hydrologic model (SAC-SMA-DS), translates the hydroclimatic traces into streamflow, which are the key inputs to the water system model.