Water availability and subsidence in California’s Central Valley

University of California, Davis (UC Davis) | September 5th, 2015

California’s Central Valley covers about 52,000 square kilometers (km2) and is one of the most productive agricultural regions in the world. More than 250 different c

California’s Central Valley covers about 52,000 square kilometers (km2) and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the broad alluvial filled structural trough, with an estimated value exceeding $20 billion per year (Faunt 2009) (Figure 1). Central Valley agriculture depends on state and federal water systems that divert surface water, predominantly originating from Sierra Nevada snowmelt, to agricultural fields. Because the valley is semi-arid and the availability of surface water varies substantially from year to year, season to season, and from north to south, agriculture, as it grew, developed a reliance on groundwater for irrigation.

Water Available for Replenishment 2018

California Department of Water Resources (DWR) | April 12th, 2018

Water Blueprint for the San Joaquin Valley Economic Impact Analysis: Phase One Results

Water Blueprint for San Joaquin Valley | February 15th, 2020

Water Budget Development for SGMA Compliance, Case Study: Ukiah Valley Groundwater Basin

Universities Council on Water Resources Journal of Contemporary Water Research & Education | December 28th, 2017

The Sustainable Groundwater Management Act (SGMA) is the first comprehensive legislative effort to reform groundwater management in the state of California after years of

The Sustainable Groundwater Management Act (SGMA) is the first comprehensive legislative effort to reform groundwater management in the state of California after years of uncoordinated and voluntary governance of this resource. The objective of this study is to: a) describe the SGMA in California, b) describe a method for estimating a water budget, and c) present the implementation of this method for the Ukiah Valley Groundwater Basin (UVGB). An estimated water budget, done on a monthly time step from 1991 to 2015, was developed in order to characterize the UVGB. Results suggest that the groundwater basin is not in overdraft, and that a portion of the Russian River is a gaining river (approximately 18,952 AF/y) from November to June, and a losing river (approximately 393 AF/y) from July to October. Furthermore, lateral groundwater movement is identified through the groundwater mass balance. Based on previous work and the results of this study, the observed later groundwater losses signify connectivity between the UVGB and the Sanel Valley Groundwater Basin (SVGB). Local groundwater managers and users can use this information to inform proposed action plans and monitoring protocols that will allow them to achieve and maintain groundwater sustainability in the UVGB by the year 2040.

Water Budgets: Foundations for Effective Water-Resources and Environmental Management

U.S. Geological Survey (USGS) | August 30th, 2007

Water budgets provide a means for evaluating availability and sustainability of a water supply. A water budget simply states that the rate of change in water stored in an

Water budgets provide a means for evaluating availability and sustainability of a water supply. A water budget simply states that the rate of change in water stored in an area, such as a watershed, is balanced by the rate at which water flows into and out of the area. An understanding of water budgets and underlying hydrologic processes provides a foundation for effective water-resource and environmental planning and management. Observed changes in water budgets of an area over time can be used to assess the effects of climate variability and human activities on water resources. Comparison of water budgets from different areas allows the effects of factors such as geology, soils, vegetation, and land use on the hydrologic cycle to be quantified. Human activities affect the natural hydrologic cycle in many ways. Modifications of the land to accommodate agriculture, such as installation of drainage and irrigation systems, alter infiltration, runoff, evaporation, and plant transpiration rates. Buildings, roads, and parking lots in urban areas tend to increase runoff and decrease infiltration. Dams reduce flooding in many areas. Water budgets provide a basis for assessing how a natural or human-induced change in one part of the hydrologic cycle may affect other aspects of the cycle. This report provides an overview and qualitative description of water budgets as foundations for effective water-resources and environmental management of freshwater hydrologic systems. Perhaps of most interest to the hydrologic community, the concepts presented are also relevant to the fields of agriculture, atmospheric studies, meteorology, climatology, ecology, limnology, mining, water supply, flood control, reservoir management, wetland studies, pollution control, and other areas of science, society, and industry. The first part of the report describes water storage and movement in the atmosphere, on land surface, and in the subsurface, as well as water exchange among these compartments. Our ability to measure these phenomena and inherent uncertainties in measurement techniques also are discussed. The latter part of the report presents a number of case studies that illustrate how water-budget studies are conducted, documents how human activities affect water budgets, and describes how water budgets are used to address water and environmental issues.

Water Features of the Smith River Plain, Del Norte County, California

U.S. Geological Survey (USGS) | December 1st, 1957

Water Heist: How Corporations are Cashing in on California’s Water

Public Citizen | December 1st, 2003

In 1994, the largest contractors with the California State Water Project (SWP)—the state’s largest water delivery system—called the Department of Water Resources (D

In 1994, the largest contractors with the California State Water Project (SWP)—the state’s largest water delivery system—called the Department of Water Resources (DWR) into a closed meeting. The agreements that the SWP contractors and the state reached in that meeting led to a document known as the Monterey Amendments, named after the city where the meetings took place. These “amendments” to the SWP contracts included denying that the SWP delivers half of what the contractors say it does and effectively deregulating the SWP so that the contractors can sell contracts for precisely the half of the water that doesn’t exist. Sound confusing? It is. Welcome to the world of “paper water.” In the same Monterey meetings, the state also agreed to give away an underground water storage facility that DWR spent $74 million purchasing and developing.

Water Quality Control Plan for the Tulare Lake Basin Third Edition

Central Valley Regional Water Quality Control Board (CVRWQCB) | May 31st, 2018

Water quality control plans, or basin plans, contain California's administrative policies and procedures for protecting state waters. Basin plans are required by the sta

Water quality control plans, or basin plans, contain California's administrative policies and procedures for protecting state waters. Basin plans are required by the state Porter-Cologne Water Quality Control Act (California Water Code Section 13240). In addition, Section 303 of the federal Clean Water Act requires states to adopt water quality standards that “consist of the designated uses of the navigable waters involved and the water quality criteria for such waters based upon such uses.” Each of California's nine regional water quality control boards must formulate and adopt a basin plan for all areas within its region. The basin plans must conform with statewide policy set forth by the legislature and by the State Water Resources Control Board. Basin plans consist of designated beneficial uses to be protected, water quality objectives to protect those uses, and a program of implementation needed for achieving the objectives {California Water Code, Section 13050(j)}. Beneficial uses, together with their corresponding water quality objectives, meet federal regulatory criteria for water quality standards. Hence, California's basin plans serve as regulatory references for meeting both State and federal requirements for water quality control {40 CFR Parts 130 and 131}.One significant difference between the state and federal programs is that California's basin plans establish standards for ground waters in addition to surface waters. Basin plans are adopted and amended by regional water boards under a structured process involving full public participation and state environmental review. Basin plans and amendments do not become effective until approved by the State Water Board. Regulatory provisions must be approved by the Office of Administrative Law. Adoption or revision of surface water standards are subject to the approval of the U. S. Environmental Protection Agency before they become accepted standards for the federal program. Basin plans complement water quality control plans adopted by the State Water Board. It is the intent of the state and regional water boards to maintain basin plans in an updated and readily available edition that reflects all current water quality control programs. The first edition of this Water Quality Control Plan for the Tulare Lake Basin (Basin Plan) was adopted by the California Regional Water Quality Control Board, Central Valley Region, on 25 July 1975, and became effective following approval by the State Water Board on 21 August 1975 and the U. S. Environmental Protection Agency (EPA) in June 1976. Although several revisions have been adopted and approved since 1975, this revision is the first complete rewrite of the text of the Basin Plan. Regional Water Board resolutions adopted prior to 17 August 1995, that revise or supplement the first edition of the plan which are not expressly incorporated by reference into the second edition of the plan are superceded. In this Basin Plan, "Regional Water Board" refers to the Central Valley Regional Water Quality Control Board and "State Water Board" refers to the State Water Resources Control Board. *Central Valley plans split between separate documents for Tulare basin and the Sacramento and San Joaquin basins. Click here for the plan for the Sacramento and San Joaquin basins.

Water Quality in Basin-Fill Aquifers of the Southwestern United States: Arizona, California, Colorado, Nevada, New Mexico, and Utah, 1993–2009

U.S. Geological Survey (USGS) | July 15th, 2014

Water Quality of Groundwater Used for Public Supply in Principal Aquifers of the Western United States

U.S. Geological Survey (USGS) | September 8th, 2020