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.

Delta Conveyance Project Operations Plan

California Department of Water Resources (DWR) | August 23rd, 2024

This document presents a summary of the Delta Conveyance Project (DCP) operations commitments that the Department of Water Resources (DWR) has made for when the DCP becom

This document presents a summary of the Delta Conveyance Project (DCP) operations commitments that the Department of Water Resources (DWR) has made for when the DCP becomes operational.

Delta Fish Agreement

California Department of Fish and Wildlife (CDFW) | December 30th, 1986

On December 30, 1986, the Directors of CDFW and the Department of Water Resources (DWR) signed an agreement to provide for offsetting fishery impacts caused by the divers

On December 30, 1986, the Directors of CDFW and the Department of Water Resources (DWR) signed an agreement to provide for offsetting fishery impacts caused by the diversion of water at the Harvey O. Banks Delta Pumping Plant (Banks), located at the head of the California Aqueduct near Tracy, California. The agreement, currently referred to as the Delta Fish Agreement (DFA or Agreement) (PDF), was previously known as the Delta Pumping Plant Fish Protection Agreement or Four Pumps Agreement because it was adopted as part of the mitigation package to add four additional pumps to Banks during the late 1980’s. Direct losses of Chinook salmon, steelhead, and striped bass are offset or mitigated through the funding and implementation of fish mitigation projects.

Delta Independent Science Board -- Comments on the Sacramento / Delta Draft Staff Report

Delta Stewardship Council (Delta Council) | January 19th, 2024

Department of Fish and Game Rationale for Effects of Exports

California Department of Fish and Wildlife (CDFW) | November 2nd, 2011

This document describes the California Department of Fish and Game (DFG) methodology to quantify the surface area in the Sacramento – San Joaquin delta estuary (Delta)

This document describes the California Department of Fish and Game (DFG) methodology to quantify the surface area in the Sacramento – San Joaquin delta estuary (Delta) that is impacted by the operations of the State Water Project (SWP) and Central Valley Project (CVP) pumping facilities. In order to estimate the mitigation required to offset direct and indirect losses of Fish Species due to impacts to surface acres of aquatic habitat in the Delta accounted to the SWP Delta Pumping Facilities operations, DFG used an analysis based on conclusions and information contained in a manuscript that utilizes the Delta Simulation Model-2 Particle Tracking Model (DSM2PTM) (Kimmerer and Nobriga, 2008). This methodology provides the general loss of “particles” to the Delta which is a surrogate for loss of productivity and fish life stages vulnerable to these effects.

Draft EIR Monterey Amendment to the State Water Project Contracts (Including Kern Water Bank Transfer) and Associated Actions as Part of a Settlement Agreement (Monterey Plus)

California Department of Water Resources (DWR) | April 1st, 2015

The California Department of Water Resources (Department), as the lead agency under the California Environmental Quality Act (CEQA), prepared the environmental impact rep

The California Department of Water Resources (Department), as the lead agency under the California Environmental Quality Act (CEQA), prepared the environmental impact report (EIR) for the Monterey Amendment to the State Water Project Contracts (Including Kern Water Bank Transfer) and Associated Actions as Part of a Settlement Agreement (Monterey Plus) (Monterey Plus EIR). The Department certified the Monterey Plus EIR on February 1, 2010. Several parties challenged the adequacy of the Monterey Plus EIR under CEQA. In 2014, the Monterey Plus EIR was found by the Sacramento County Superior Court (Court) to comply with CEQA in all aspects except with respect to the development, use, and operation of the Kern Water Bank (KWB). The Court specified that the Department is to correct the deficiencies and recertify the EIR without reopening the non-defective portions of the EIR. Upon recertification, only those portions of the Revised EIR (REIR) that are new or changed shall be subject to challenge under CEQA by petitioners or other interested parties. For these reasons, the Department has developed this three-volume Monterey Plus Draft Revised EIR. Document A1 presents all the changes to the Monterey Plus EIR made as a result of the Department’s reanalysis of the Kern Fan Element (KFE) property transfer and new analysis of the KWB development and continued use and operation.  Since DWR decertified the Monterey Plus EIR, pursuant to the Court’s order, the Revised EIR also includes, without modification, the 2007 Draft EIR (Document B, including Volumes I and II) and the 2010 Final EIR (Document C, including Volumes I and II). Together, the three documents constitute the Monterey Plus Draft Revised EIR (Figure P-1). The Draft Revised EIR focuses on the development and continued use and operations of the KWB near Bakersfield. Potentially significant impacts before mitigation were related to groundwater levels and quality, Kern River water quality, the Cross Valley Canal, terrestrial biological resources, erosion, hazardous materials, waterborne disease, cultural and paleontological resources, greenhouse gas emissions, and cumulative impacts.  Potentially significant and unavoidable impacts were related to cumulative growth-related impacts. The Draft Revised EIR identifies hazardous sites on or near KWB Lands that have been remediated.

Draft finding of no significant impact, 2-Gates Fish Protection Demonstration Project.

U.S. Bureau of Reclamation (USBR) | November 13th, 2009

The proposed Demonstration Project is a 5-year experiment to validate a new delta smelt behavioral model and study the effects of modifying flows in the Sacramento-San Jo

The proposed Demonstration Project is a 5-year experiment to validate a new delta smelt behavioral model and study the effects of modifying flows in the Sacramento-San Joaquin Delta (Delta) to protect delta smelt and other sensitive aquatic species from entrainment in Central Valley Project (CVP) and State Water Project (SWP) export pumps. Research suggests that the pre-spawning migration of adult delta smelt is tied to sediment/suspended particles in the water (turbidity). Temporary gates would be placed across Old River and Connection Slough in the central Delta and operated from December to March to keep turbid water away from the CVP and SWP export pumps, thus keeping adult delta smelt away from the pumps, and in March and June to prevent larvae and juvenile delta smelt from being entrained by the export pumps.

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

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

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

This white paper describes current understanding of how the Department of Water Resources (DWR) would account for and administer the Delta Conveyance Facility (DCF) Benefits. DWR will include information regarding the accounting and administration of water attributable to DCF in relevant Notice(s) to State Water Project Contractors consistent with prior practice. No legally binding obligations are created by this white paper. This white paper may be updated from time to time by DWR, in consultation with the Public Water Agencies (PWAs), in response to factors including, but not limited to, changes in laws, regulations or permits applicable to DWR and/or the State Water Project (SWP). Capitalized terms not defined herein shall have the meanings ascribed to them in the DCF Agreement in Principle (AIP).

Effect of the South Delta Agricultural Barriers on Emigrating Juvenile Salmonids

California Department of Water Resources (DWR) | November 15th, 2018

The California Department of Water Resources’ (DWR) Temporary Barriers Project (TBP) is an ongoing project that installs, operates, and monitors up to four temporary ro

The California Department of Water Resources’ (DWR) Temporary Barriers Project (TBP) is an ongoing project that installs, operates, and monitors up to four temporary rock-fill barriers constructed in waterways located in the southern portion of the Sacramento-San Joaquin Delta (Delta) near the cities of Tracy and Lathrop in San Joaquin County, California (Figure 1-1). Three of the temporary barriers—Old River at Tracy (ORTB), Middle River (MRB), and Grant Line Canal (GLCB), collectively, the south Delta agricultural barriers (SDABs)—are constructed and operated during the agricultural irrigation season, usually April through November. The SDABs are designed to act as flow control structures, retaining tidal fresh water behind each barrier following a flood tide. The fourth barrier, Head of Old River Barrier (HORB), is installed during the spring and fall as a fish guidance barrier. The HORB is normally installed in the spring to prevent juvenile fall-run San Joaquin River Chinook Salmon (Oncorhynchus tshawytscha) and juvenile Central Valley steelhead (Oncorhynchus mykiss) 2 from emigrating through Old River toward the south Delta water export facilities at the intakes of the State Water Project (SWP) and federal Central Valley Project (CVP). In the fall, the HORB helps to guide adult San Joaquin River Chinook Salmon to spawning locations in the upper watershed. Installation, operation, and removal of the SDABs has the potential to harm, harass, or cause mortality to fish species of management concern to the National Marine Fisheries Service (NMFS), specifically, juvenile fall-run Chinook Salmon which are NMFS Species of Concern (NMFS 2010), juvenile Central Valley steelhead which is a threatened species, an Endangered Species Act (ESA) Section 10j experimental population (63 Federal Register [FR] 13347), and juvenile Green Sturgeon (Acipenser medirostris), also a federally listed threatened species (71 FR 17757). The TBP is implemented in compliance with the terms and conditions of two NMFS Biological Opinions (BiOp) (NMFS 2008, 2009).

Effects of Hydraulic Conditions on Salvage Efficiency of Adult Delta Smelt at the Tracy Fish Collection Facility

U.S. Bureau of Reclamation (USBR) | February 29th, 2016