South Lahontan

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 Water Plan Update 2013: South Lahontan Hydrologic Region Report

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

Several of California’s well-known natural resources are located in the South Lahontan Hydrologic Region. They include Mono Lake, Death Valley, the Owens Valley, and th

Several of California’s well-known natural resources are located in the South Lahontan Hydrologic Region. They include Mono Lake, Death Valley, the Owens Valley, and the Mojave Desert. Two of California’s fastest developing urban areas over the past several decades are also in the region — the Antelope and Victor valleys. Agriculture, although small in acreage, has remained steady over the years. Projections of continued growth have induced local water agencies to develop new water supplies and increase the reliability of existing water supplies. With additional stakeholders helping to study and resolve these issues under Integrated Regional Water Management planning programs, these actions have intensified in recent years and are reflected in the following discussion.

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.

California Water Plan Update 2023 (Final Version)

California Department of Water Resources (DWR) | April 3rd, 2024

Updated every five years, the Water Plan is the State’s strategic plan for sustainably and equitably managing, developing, and stewarding water resources. Required by W

Updated every five years, the Water Plan is the State’s strategic plan for sustainably and equitably managing, developing, and stewarding water resources. Required by Water Code Section 10005, the plan presents the status and trends of California’s water-dependent natural resources; water supplies; and agricultural, urban, and environmental water demands for a range of plausible future scenarios.

California Water Plan Update 2023 Public Review Draft

California Department of Water Resources (DWR) | September 20th, 2023

The California Water Plan (Water Plan), updated every five years, is the State’s strategic plan for sustainably and equitably managing, developing, and stewarding water

The California Water Plan (Water Plan), updated every five years, is the State’s strategic plan for sustainably and equitably managing, developing, and stewarding water resources. Required by Water Code Section 10005, the plan presents the status and trends of California’s water-dependent natural resources; water supplies; and agricultural, urban, and environmental water demands for a range of plausible future scenarios.

California Water Resilience Portfolio

State of California | July 28th, 2020

California's Fourth Climate Change Assessment Statewide Summary Report

Governor's Office of Planning and Research (OPR) | August 27th, 2018

California’s Fourth Climate Change Assessment (Fourth Assessment) advances actionable science that serves the growing needs of state and local-level decision-

California’s Fourth Climate Change Assessment (Fourth Assessment) advances actionable science that serves the growing needs of state and local-level decision-makers from a variety of sectors. This cutting-edge research initiative is comprised of a wide-ranging body of technical reports, including rigorous, comprehensive climate change scenarios at a scale suitable for illuminating regional vulnerabilities and localized adaptation strategies in California; datasets and tools that improve integration of observed and projected knowledge about climate change into decision- making; and recommendations and information to directly inform vulnerability assessments and adaptation strategies for California’s energy sector, water resources and management, oceans and coasts, forests, wildfires, agriculture, biodiversity and habitat, and public health. In addition, these technical reports have been distilled into summary reports and a brochure, allowing the public and decision-makers to easily access relevant findings from the Fourth Assessment. Click here for key findings brochure

California's Groundwater Conditions Semi-Annual Update: March 2023

California Department of Water Resources (DWR) | March 15th, 2023

These updates are part of the informational resources associated with DWR’s California’s Groundwater (Bulletin 118). This report uses groundwater data received electr

These updates are part of the informational resources associated with DWR’s California’s Groundwater (Bulletin 118). This report uses groundwater data received electronically by DWR as of February 15, 2022, through the conclusion of Water Year 2022, and the start of Water Year 2023.

California's Groundwater Conditions: Semi Annual Update May 2024, Spring Bulletin 118

California Department of Water Resources (DWR) | May 6th, 2024

In WY 2023, increased surface water supply led to a significant reduction in statewide groundwater extraction, amounting to a total annual extraction of 9.5 million acre-

In WY 2023, increased surface water supply led to a significant reduction in statewide groundwater extraction, amounting to a total annual extraction of 9.5 million acre-feet, a stark contrast to the 17 million acre-feet extracted in WY 2022.