Scenarios of Future California Water Demand Through 2050

California Department of Water Resources (DWR) | August 14th, 2014

This paper describes the application of future scenarios for Water Plan Update 2013 (DWR 2013) to quantify future water demand for California and our 10 hydrologic region

This paper describes the application of future scenarios for Water Plan Update 2013 (DWR 2013) to quantify future water demand for California and our 10 hydrologic regions out to the year 2050. Starting with the publication of California Water Plan Update 2005 (DWR 2005), DWR has applied the concept of scenarios to describe future water management conditions. Scenarios are used to capture a broad range of uncertain factors that affect water management that are considered to be beyond the control of water managers. For Update 2013 scenarios were organized around narrative themes of growth and climate change, which were then quantified using factors about future population growth, housing densities, land use patterns, and climate.  For Updates 2005 and 2009, DWR attempted only to quantify future water demand management strategies at the hydrologic region scale. The hydrologic regions are large areas of tens of thousands square miles, too large to compute meaningful information on regional water management actions. But in parallel to the hydrologic region scale analysis as in current Update 2013, DWR has been pursuing a longer term project, to perform a more complete hydrologic analysis at the finer planning area scale. Results and analysis of planning area water management strategies is given in a separate report.  In addition to this paper, background information on the application of scenarios can be found in Chapter 5 and 6 of Update 2013. Chapter 5 provides information how scenarios are used to quantify water management uncertainty. Chapter 6 describes DWR’s efforts to effect long term improvements in data and analytical tools to support the Water Plan. 

Science and Decision Making: Water Management and Tree‐Ring Data in the Western United States

American Water Resources Association (AWRA) | October 5th, 2009

Growing populations, limited resources, and sustained drought are placing increased pressure on already over‐allocated water supplies in the western United States, prom

Growing populations, limited resources, and sustained drought are placing increased pressure on already over‐allocated water supplies in the western United States, prompting some water managers to seek out and utilize new forms of climate data in their planning efforts. One source of information that is now being considered by water resource management is extended hydrologic records from tree‐ring data. Scientists with the Western Water Assessment (WWA) have been providing reconstructions of streamflow (i.e., paleoclimate data) to water managers in Colorado and other western states (Arizona, New Mexico, and Wyoming), and presenting technical workshops explaining the applications of tree‐ring data for water management for the past eight years. Little is known, however, about what has resulted from these engagements between scientists and water managers. Using in‐depth interviews and a survey questionnaire, we attempt to address this lack of information by examining the outcomes of the interactions between WWA scientists and western water managers to better understand how paleoclimate data has been translated to water resource management. This assessment includes an analysis of what prompts water managers to seek out tree‐ring data, how paleoclimate data are utilized by water managers in both quantitative and qualitative ways, and how tree‐ring data are interpreted in the context of organization mandates and histories. We situate this study within a framework that examines the coproduction of science and policy, where scientists and resource managers collectively define and examine research and planning needs, the activities of which are embedded within wider social and political contexts. These findings have broader applications for understanding science‐policy interactions related to climate and climate change in resource management, and point to the potential benefits of reflexive interactions of scientists and decision makers.

Scientist and Stakeholder Views on the Delta Ecosystem

Public Policy Institute of California (PPIC) | April 22nd, 2013

There is broad scientific recognition that a wide range of ecosystem stressors are responsible for the declines in native fish populations in the Sacramento–San Joaquin

There is broad scientific recognition that a wide range of ecosystem stressors are responsible for the declines in native fish populations in the Sacramento–San Joaquin Delta. But science and policymaking have been at odds about the roles of different stressors and the potential of various management actions to improve ecosystem health. In the summer of 2012, PPIC conducted two confidential surveys on the impact of ecosystem stressors: one sought input from scientific experts and the other focused on stakeholders and policymakers. This report analyzes the results and examines the implications of both surveys.

Scott Valley Integrated Hydrologic Model: Data Collection, Analysis, and Water Budget Final Report

University of California, Davis (UC Davis) | November 14th, 2017

The Scott Valley is an agricultural groundwater basin in Northern California, within the Scott River watershed and part of the much larger Klamath Basin watershed straddl

The Scott Valley is an agricultural groundwater basin in Northern California, within the Scott River watershed and part of the much larger Klamath Basin watershed straddling the California-Oregon border. The Scott River provides important habitat for salmonid fish, including spawning and rearing habitat for coho and fall-run Chinook salmon and steelhead trout. Sufficient flows at adequately low temperatures during summer, for rearing, and fall, for spawning, are critical for healthy fish habitat in the mainstem and tributaries. This report presents the data assembled and the methods used for data analysis and data modeling to prepare the Scott Valley Integrated Hydrologic Model Version 2, which is currently under development. The report includes precipitation data analysis, streamflow data analysis and modeling, geology and groundwater data review and analysis, evapotranspiration and soils data analysis, and preparation of relevant watershed, land use, topography, and irrigation data. The data collection and analysis efforts culminate in the development of a spatio-temporally distributed soil water budget model for the Scott Valley. The soil water budget model is used to determine spatially and temporally varying groundwater pumping rates, surface water diversion rates, and groundwater recharge across the groundwater basin. The spatial resolution of the soil water budget model is by individual fields (land use polygons). Temporal discretization is in daily time steps for the period from October 1, 1990 to September 30, 2011. This period includes several dry years, average years, and wet year periods. Methods and results of the soil water budget model are presented in this report. This report represents the next step toward a better understanding of the interactions between groundwater, surface water, land-use, and agricultural practices with a specific focus on the seasonal impacts of groundwater pumping on streamflow during critical low flow periods. The work presented here relies on an extensive data collection facilitated by the voluntary and active collaboration of communities, landowners, the Scott River Watershed Council (SRWC), the Siskiyou Resource Conservation District (SRCD), and the Scott Valley Groundwater Advisory Committee (GWAC) which has been appointed by the Board of Supervisors in January 2011, meeting monthly since April 2011 and advising UC Davis on its data collection and modeling efforts. In the data analysis and during the model development, numerous assumptions have been made as is common in building a conceptual and numerical integrated hydrologic model. Models cannot represent the complexity of the real system, but are an effort to capture salient hydrologic features with sufficient accuracy to develop modeling results that are useful for a better understanding of the watershed dynamics and water balance.

Sea Level Variations of the United States 1854–2006

National Oceanic and Atmospheric Administration (NOAA) | December 19th, 2009

The United States National Water Level Network (NWLON) was established in the 19th Century to ensure the Nation’s nautical charts, shoreline maps, and elevations relat

The United States National Water Level Network (NWLON) was established in the 19th Century to ensure the Nation’s nautical charts, shoreline maps, and elevations relative to homes, levees, and other coastal infrastructure were accurately referenced to sea level. In support of this mission, NOAA’s Center for Operational Oceanographic Products and Services and its predecessors have determined sea level for the United States since the mid 19th Century. While climate change was not a concern during the mid-1800s, the accurate determination of sea level was critical for navigation and marine boundary determination. To meet these important requirements, technology, procedures, and processes were developed to the highest scientific and engineering standards. At the turn of the 20th Century it was realized that there was a need to account for a rise in sea level and the first National Tidal Datum Epoch was established. Today this Epoch is updated every 20 to 25 years. The Supreme Court recognized these standards and procedures in the landmark 1936 case of Borax, Ltd v. City of Los Angeles when legally defining sea level. Due to those initial efforts and the continued dedication of those charged with the responsibility for monitoring sea level for the United States, we can accurately determine relative (local) mean sea level along the Nation’s coastline today. These observations also play an important role in monitoring change in global sea level. As we monitor change in sea level into the 21st Century, the statement made by Alexander Dallas Bache, the Second Superintendent of the Coast Survey, is as relevant today as when it was stated more than 150 years ago, “It seems a very simple task to make correct tidal observations; but, in all my experience, I have found no observations which require such constant care and attention” (1854). Michael Szabados, Director, Center for Operational Oceanographic Products and Services

Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future

National Academy of Sciences (NAS) | December 13th, 2012

Second Supplement to State Water Resources Board Bulletin No. 11, San Joaquin County Investigation, Basic Data, Calaveras Unit, 1955-56

California Department of Water Resources (DWR) | April 20th, 1957

Sediment Supply to San Francisco Bay, Water Years 1995 through 2016: Data, trends, and monitoring recommendations to support decisions about water quality, tidal wetlands, and resilience to sea level rise

San Francisco Estuary Institute (SFEI) | June 11th, 2018

Knowledge of the status and trends of sediment supply to San Francisco Bay is critically important for management decisions about dredging, marsh restoration, flood contr

Knowledge of the status and trends of sediment supply to San Francisco Bay is critically important for management decisions about dredging, marsh restoration, flood control, contaminants, water clarity (in relation to primary production), and sea level rise. Several site-specific studies of sediment supply to San Francisco Bay have been conducted, but no synthesis of recent studies is available. The purpose of this report is to synthesize the best available data and knowledge to answer a few of the key study questions related to sediment supply to the Bay.  This synthesis report was prepared jointly by the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) and the U. S. Geological Survey (USGS) with funding from both organizations. The project is meant to be a step in the development of a more comprehensive sediment management and monitoring strategy for the Bay. 

Selected Federal Water Activities: Agencies, Authorities, and Congressional Committees

Congressional Research Service (CRS) | ?

More than two centuries of federal water resource activity have resulted in a complex web of federal involvement in water resource development, management, protection, an

More than two centuries of federal water resource activity have resulted in a complex web of federal involvement in water resource development, management, protection, and use. As a result, Congress faces challenges related to overlap and gaps in federal water resource activities and in coordination and consistency among federal programs. Further, many federal authorities are discretionary or funded by discretionary appropriations. Consequently, there can be a significant difference between what federal agencies are authorized to do and what they are actually doing, and no one committee in Congress oversees this dichotomy. Although the responsibility for development, management, protection, and allocation of the nation’s water resources is spread among federal, state, local, tribal, and private interests, this report focuses on federal activities related to water and the congressional committees that authorize and oversee these activities. The report covers multiple topics and individual water-related subtopics ranging from water supply and water quality infrastructure to fisheries management and water rights. The report is not exhaustive; instead, the authors have attempted to cover the major federal activities authorized by Congress that affect water resource development, management, protection, and use in the United States. Similarly, the analysis does not cover every aspect of House and Senate committee jurisdiction affecting water issues. For definitive evaluation of committee jurisdictions related to water, the views of the House and Senate Parliamentarian Offices are official. The report covers four general areas, or themes: (1) “Water Resources Development, Management, and Use”; (2) “Water Quality, Protection, and Restoration”; (3) “Water Rights and Allocation”; and (4) “Research and Planning.” The sections addressing these themes are further divided into tables that list topic areas and individual water-related subtopics. For each subtopic, CRS has identified selected federal agencies and activities related to the subtopic, authorities for such activities, and relevant House and Senate committee jurisdictions, as specified in House and Senate rules. Appendixes address considerations in determining House and Senate committee jurisdictions and present the official language from House Rule X and Senate Rule XXV, respectively, which are indicators of congressional jurisdiction over water resources. The report also includes a glossary of abbreviations for federal agencies and House and Senate committees. The nine tables that make up the body of this report underscore the complexity of federal activities affecting water resource development, management, protection, and use in the United States. As apparent throughout these tables, numerous standing committees in the House and the Senate have jurisdiction over various components of federal water policy. The wide range of federal executive responsibilities for water resources reflects comparably complex congressional legislative responsibilities and directives.

SGMA Best Management Practice: Hydrogeologic Conceptual Model

California Department of Water Resources (DWR) | December 23rd, 2016

The objective of this Best Management Practice (BMP) is to assist in the use and development of hydrogeologic conceptual models (HCM). The California Department of Water

The objective of this Best Management Practice (BMP) is to assist in the use and development of hydrogeologic conceptual models (HCM). The California Department of Water Resources (the Department or DWR) has developed this document as part of the obligation in the Technical Assistance Chapter (Chapter 7) of the Sustainable Groundwater Management Act (SGMA) to support the long-term sustainability of California’s groundwater basins. Information provided in this BMP is meant to provide support to Groundwater Sustainability Agencies (GSAs) when developing a HCM in accordance with the Groundwater Sustainability Plan (GSP) Emergency Regulations (GSP Regulations). This BMP identifies available resources to support development of HCMs. This BMP includes the following sections: Objective. The objective and brief description of the contents of this BMP. Use and Limitations. A brief description of the use and limitations of this BMP. HCM Fundamentals. A description of HCM fundamental concepts. Relationship of HCM to other BMPs. A description of how the HCM relates to other BMPs and is the basis for development of other GSP requirements. Technical Assistance. A description of technical assistance to support the development of a HCM and potential sources of information and relevant datasets that can be used to further define each component. Key Definitions. Definitions relevant for this BMP as provided in the GSP and Basin Boundary Regulations and in SGMA. Related Materials. References and other materials that provide supporting information related to the development of HCMs.