San Francisco Bay

California Groundwater Conditions Update – Spring 2019

California Department of Water Resources (DWR) | October 3rd, 2022

DWR has completed an evaluation of state-wide groundwater level data reported in spring 2019 for California groundwater basins. Spring data correspond to the time period

DWR has completed an evaluation of state-wide groundwater level data reported in spring 2019 for California groundwater basins. Spring data correspond to the time period immediately before the typical irrigation season begins in a region. This helps show groundwater levels before summer crop irrigation and other uses. In Central and Northern California, the pre-irrigation season is in March, while in Southern California, that season is typically earlier. The Spring 2019 Groundwater Level Data Coverage map (Figure 1) shows a comparison between total spring 2019 reporting and typical reporting in previous years. Typical reporting includes wells with water level data submitted to DWR over the past five spring seasons (2015-2019) by CASGEM Monitoring Entities, other local agencies, and well owners. Although the reporting percentage is high and coverage is good, there are still gaps in spring 2019 coverage throughout the state, including portions of Tulare, Kern, San Bernardino, Riverside, and Imperial counties.

California Groundwater Conditions Update – Spring 2020

California Department of Water Resources (DWR) | October 3rd, 2022

In this report, groundwater level change values compare spring 2020 to spring 2019, 2017, 2015, and 2010. The information is summarized in Table 1. Spring groundwater lev

In this report, groundwater level change values compare spring 2020 to spring 2019, 2017, 2015, and 2010. The information is summarized in Table 1. Spring groundwater level data are an important indicator of groundwater conditions because spring generally corresponds to the pre-irrigation season. This time period is representative of the water year’s peak groundwater levels. Associated maps display groundwater level increases and decreases and summarize data by hydrologic region.

California Groundwater Conditions Update – Spring 2021 California’s drought and groundwater

California Department of Water Resources (DWR) | October 3rd, 2022

This report uses maps to depict how groundwater levels have changed over time using two different analytical methods. One method, groundwater level change maps, show the

This report uses maps to depict how groundwater levels have changed over time using two different analytical methods. One method, groundwater level change maps, show the change in groundwater levels between two different springtime measurements. The second method uses trend analysis of water levels for wells having at least 10 annual springtime measurements over a 20-year period to illustrate the statistical magnitude and direction of groundwater level change (a well’s water level increasing or decreasing trend over time). Spring groundwater level data are an important indicator of groundwater conditions because spring generally corresponds to both the pre-irrigation season and the peak groundwater levels in a water year.

California Hydraulic Mining under the Caminetti Act

Scientific American | July 21st, 1900

The gold deposits of California are, for a large part, contained in gravel beds once the channel of rivers which formed the drainage of the west slope of th

The gold deposits of California are, for a large part, contained in gravel beds once the channel of rivers which formed the drainage of the west slope of the Sierra Nevada Mountains. In the course of ages new rivers were formed, leaving the ancient gravel beds elevated often hundreds of feet above the river beds of the present. The depth of the gravel in the old channels is often several hundred feet and the width across them frequently one-half mile, while their courses may be traced for thirty or forty miles in length in detached sections, which are the remnants of once continuous beds. Denudation and the cutting down of the present streams has removed parts of the ancient channels and they often disappear below the surface for several miles underneath coverings of lava which have been spread over them ...  Hydraulic mining became an immense industry. At the time when it had reached its greatest development it was estimated that more than one hundred millions of dollars had been invested in the construction of water supplies, mining plant, tunnels, and flumes, and more than two million dollars have been spent in the equipment of a single mine. Everything was upon an immense scale, and the amounts of gravel removed were in proportion. So large, in fact, that the material washed into the streams caused blockages over spreading agricultural lands in the Sacramento Valley, obstructing and raising the beds of the navigable rivers which enter San Francisco Bay, causing inundations at times of flood, and generally making its influence noticeable 200 miles from the seat of mining. In 1880 it was estimated that in the bed of the Yuba River alone there were stored more than one hundred and forty million cubic yards of accumulations, and the bed of the river had spread over a width of two and one-half miles between the side levees built to confine the spread of the deposits.

California Salmon Strategy for a Hotter, Drier Future: Restoring Aquatic Ecosystems in the Age of Climate Change

California Department of Fish and Wildlife (CDFW) | January 20th, 2024

The infrastructure built generations ago in California continues to limit salmon migration, and some dams that remain on the landscape are well beyond their useful life.

The infrastructure built generations ago in California continues to limit salmon migration, and some dams that remain on the landscape are well beyond their useful life. In the Central Valley, large dams were built starting in the early 1900s on almost all major rivers. Those dams now block salmon access to over 90 percent of their historical spawning and rearing habitat higher in mountain streams.

California Single Family Water Use Efficiency Study

California Department of Water Resources (DWR) | April 20th, 2011

The California Single Family Home Water Use Efficiency Study includes data from many traditional sources such as billing data, survey data, weather data and aerial photo

The California Single Family Home Water Use Efficiency Study includes data from many traditional sources such as billing data, survey data, weather data and aerial photo information to analyze the water use patterns of a sample of over 700 single-family homes across ten water agencies throughout the State of California. Detailed flow trace data was obtained from portable data loggers which were attached to the water meters of each of the study homes. These flow traces provided flow readings at ten second intervals from the magnetic pickup, which generate 80-100 pulses per gallon. These highly detailed flow data make it possible to identify individual water use events and to categorize them by their end-use. The flow trace data tell not just how many gallons per day the home used, but how many gallons per day were used for individual end uses such as toilet flushing, clothes washing, dishwashers, showers, irrigation, faucets and leaks. Detailed use information can be pulled from the trace, giving for example, a count of toilet flushes and toilet flush volumes during a logging period. Researchers used flow trace data to determine levels of daily use in the homes and the efficiency of that use. Although the flow trace technique contains marginal error, such as from the mis-categorization of some events, it provides information on end uses-that is not available from any other source. This report summarizes the results of the study which began in 2005 and was completed in 2010. Water use patterns found during the 2007 logging period were analyzed to show how much potential remains for conservation savings from both indoor and outdoor efforts. 

California State Water Project: Past, Present, Future

California Department of Water Resources (DWR) | July 1st, 2006

California Water Plan 2013: Sacramento-San Joaquin Delta Regional Report

California Department of Water Resources (DWR) | October 30th, 2014

Some areas of the state with common water issues or interests cross the boundaries from one hydrologic region to another. To acknowledge this, the California Department o

Some areas of the state with common water issues or interests cross the boundaries from one hydrologic region to another. To acknowledge this, the California Department of Water Resources (DWR) developed the concept of “overlay areas” and first described overlay areas in California Water Plan Update 2005. The purpose of the overlay areas is to collect and provide information that will better enable planners and decision-makers to address issues in areas of special interest where both of the following criteria apply: (1) the area is of statewide significance — meaning that water management strategies and actions taken in one area affect much of the remainder of the state — and (2) common water management conditions exist in the area — meaning that issues and integrated planning opportunities span more than one of the 10 hydrologic regions. The two overlay areas of special interest are the Sacramento-San Joaquin Delta (Delta) and Mountain Counties.  For Update 2005, the Delta and Suisun Marsh were included as an overlay area because of its common characteristics, environmental significance, and the important role it has in the State’s water systems. The Delta and Suisun Marsh encompasses about 840,000 acres of tidal influenced land near the confluence of the Sacramento and San Joaquin rivers; and occupies portions of the Sacramento, San Joaquin, and San Francisco hydrologic regions. The geographic extent of the Delta overlay coincides with the statutory Delta boundary that defines the Legal Delta (California Water Code [CWC] Section 12220) and the Suisun Marsh as defined in California Public Resources Code Section 29101.

California Water Plan 2013: San Francisco Bay Hydrologic Region Report

California Department of Water Resources (DWR) | October 30th, 2014

The San Francisco Bay Hydrologic Region (Bay Region) has many significant water management challenges — sustaining water supply, water quality, and the ecosystems in an

The San Francisco Bay Hydrologic Region (Bay Region) has many significant water management challenges — sustaining water supply, water quality, and the ecosystems in and around San Francisco Bay; reducing flood damages; and adapting to impacts from climate change. In addition to these topics, a thorough discussion of climate change is presented including precipitation variability, reduced snowpack accumulation in the Sierra Nevada, and vulnerability of developed bay and coastal areas to sea level rise. With strong water planning and governance and several resource management strategies that can be applied, the region is poised to address these challenges effectively.

California Water Plan Update 2018, Supporting Documentation for Water Portfolios

California Department of Water Resources (DWR) | April 15th, 2019

California Water Plan Update 2018 (Update 2018) supporting documentation for water portfolios includes descriptions and accountings of water uses and their supplies for t

California Water Plan Update 2018 (Update 2018) supporting documentation for water portfolios includes descriptions and accountings of water uses and their supplies for the state in Figures 1 and 5, and for 10 hydrologic regions in Figures 7 through 16. They include pictures of conditions in California, along with water balance data for Water Years (WYs) 2011–2015. Regional inflow and outflow Figures 17 and 18 provide a geographic overview of California and surface water inflows and outflows with adjoining states, between hydrologic regions, and to the Pacific Ocean, for a wet year between two drought sequences, and a critically dry year in a drought sequence. More extreme and variable hydrology seems to have become the new normal, and not just for California. California has been, and will continue to be, a useful example of extremes brought on by a wide variety of climates and terrains. To better understand these diversities, plan for future needs, and move toward water resources sustainability, the California Department of Water Resources (DWR) analyzes water use and supply conditions for each water year at various spatial scales for the entire state. This accounting of water uses and supplies is the only statewide analysis that exists. The California Water Plan (Water Plan) water balance data is used by many in and out of the water community. Data and information requests come from other DWR programs, State and federal agencies, cities and counties, local water agencies and purveyors, research institutes, universities, non-governmental organizations, private sector companies, lawyers, elected officials, news media, documentaries, book writers, students, interested public, other states, and even other countries because California is recognized as a leader in integrated water resources management. The following excerpt is from Update 2018, Chapter 1, “California Water Today,” section on California’s Diverse Water Supplies and Uses.