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 Conveyance Project: Modernizing California’s Water Infrastructure, Fast Facts 2024

California Department of Water Resources (DWR) | September 13th, 2023

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

Delta Operations for Salmonids and Sturgeon (DOSS) Technical Working Group

Delta Stewardship Council (Delta Council) | November 1st, 2018

Delta-Mendota Canal Recirculation Feasibility Study Plan Formulation Report

U.S. Bureau of Reclamation (USBR) | September 30th, 2010

The U.S. Department of the Interior, Bureau of Reclamation (Reclamation) is evaluating the feasibility of using recirculation strategies to improve water quality and flow

The U.S. Department of the Interior, Bureau of Reclamation (Reclamation) is evaluating the feasibility of using recirculation strategies to improve water quality and flow in the lower San Joaquin River (SJR). Specifically, Reclamation is evaluating the feasibility of the Delta-Mendota Canal (DMC) Recirculation Project (Project) in which water from the Sacramento–San Joaquin River Delta (Delta) would be recirculated through the Central Valley Project (CVP) pumping and conveyance facilities to the SJR upstream from Vernalis. The DMC, which is part of the CVP, would be the primary conveyance facility utilized. The DMC is 120-mile canal that begins at the C.W. “Bill” Jones Pumping Plant (Jones) and ends at Mendota Pool, near the town of Mendota. Jones pumps water from the Delta into the canal. Water would be released from the canal into either Newman Wasteway or Westley Wasteway and would flow back into SJR near its confluence with the Merced River (Newman Wasteway) or with the Tuolumne River (Westley Wasteway). The water would re-enter the Delta near the town of Vernalis. In 2004, Reclamation initiated the DMC Recirculation Project Feasibility Study (Study). The Study is authorized by the CALFED (California Federal Bay-Delta Program) Bay-Delta Authorization Act of 2004 (118 Stat. §§ 1681-1702.; Public Law 108-361) and a similar study is required by the State Water Resources Control Board (SWRCB) as part of Water Right Decision 1641 (D-1641). The purposes of the PFR are (1) to provide information on the existing and potential resources that may be affected by the Project and (2) to present the results of the evaluation of the alternative plans that were carried forward from the 2008 Initial Alternatives Information Report (IAIR). The alternative plans are compared and ranked and the next steps in the study are presented.

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 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.

DRAFT Staff Report/Substitute Environmental Document in Support of Potential Updates to the Water Quality Control Plan for the San Francisco Bay/Sacramento-San Joaquin Delta Estuary for the Sacramento River and its Tributaries, Delta Eastside Tributaries, and Delta

California State Water Resources Control Board (SWRCB) | September 28th, 2023