Intensification of hydrological drought in California by human water management

American Geophysical Union (AGU) | January 25th, 2017

Irrigating Machinery on the Pacific Coast

Scientific American | December 17th, 1887

In offering the present paper to the Institution of Mechanical Engineers, the author does so with a tolerably complete knowledge of the very advanced practice in England

In offering the present paper to the Institution of Mechanical Engineers, the author does so with a tolerably complete knowledge of the very advanced practice in England in this class of machinery: and his purpose is mainly to explain the differences that have been called for by local circumstances in California. Character of the Country: The western or Pacific slope of the Sierra Nevada or coast range of mountains in California is very abrupt, the crests of the range being so near that the snow is visible from the coast during the whole year. Hundreds of streams cross this narrow country, falling either direct into the Pacific Ocean or into the great basin formed by the Sacramento and San Joaquin rivers. These two rivers. the largest in California, run in opposite directions nearly parallel with the coast and meet at the Bay of San Francisco forming ac ontinuous valley 400 miles long and from 50 to 100 miles wide. The small streams for the most part are fed by melting snow in the summer; and every gulch or canon has its rivulet or brook. They increase in volume until they pass into or through the hills at the foot of the mountain range; and there, unless of considerable size, they may wholly disappear in summer by percolation through the silt or by evaporation. Streams exposed to the torrid air which in summer sweeps across the sand deserts of Southern California are dried up with wonderful rapidity. The evaporation from Salt Lake, exposed to the same dry wind, is sometimes equal to half an inch per day. or 64 million tons of water. Not withstanding this great loss by evaporation, the quantity of water falling into the ocean on the coast of California has been estimated at 100 million cubic feet or 2 3/4 million tons per minute, enough, if distributed properly, to irrigate 25,000 square miles.

Irrigation in California

Scientific American | January 5th, 1884

Irrigation of Twelve Million Acres in the Valley of California

U.S. Geological Survey (USGS) | November 15th, 1920

Irrigation Water Use in the Central Valley of California

California Department of Water Resources (DWR) | January 1st, 1985

Isolating the Poroelastic Response of the Groundwater System in InSAR Data From the Central Valley of California

American Geophysical Union (AGU) | April 28th, 2023

James Groundwater Sustainability Agency Groundwater Sustainability Plan

James Groundwater Sustainability Agency (JGSA) | December 12th, 2019

James Groundwater Sustainability Agency Groundwater Sustainability Plan (Revised)

James Groundwater Sustainability Agency (JGSA) | July 22nd, 2022

*Submitted to the Department of Water Resources on July 22, 2022. No date or signature accompany the seal from the preparer at Provost and Pritchard.

*Submitted to the Department of Water Resources on July 22, 2022. No date or signature accompany the seal from the preparer at Provost and Pritchard.

Kaweah Subbasin Probationary Hearing Draft Staff Report

California State Water Resources Control Board (SWRCB) | May 2nd, 2024

The State Water Board recognizes that local public agencies in the Kaweah Subbasin have made significant efforts since the passage of SGMA to form three groundwater susta

The State Water Board recognizes that local public agencies in the Kaweah Subbasin have made significant efforts since the passage of SGMA to form three groundwater sustainability agencies (GSAs) and then develop detailed technical and other information supporting the adoption and implementation of three groundwater sustainability plans (GSPs) for the subbasin. Despite those efforts, in January of 2020, DWR reviewed the three GSPs to determine if the GSPs met SGMA’s requirements and found the GSPs to be incomplete. Following revisions made by the GSAs in the subbasin, DWR reevaluated the GSPs in March of 2023, determined the GSPs to be inadequate, and referred the subbasin to the State Water Board, as required by SGMA. Consistent with SGMA, the State Water Board may now consider whether to designate the Kaweah Subbasin as a “probationary basin,” a term that is used in SGMA to describe a basin in the first stage of state intervention.  Click here for Water Board updates on hearings. A January 5, 2025 has been cancelled to allow more time to review updated groundwater sustainability plans.

Kaweah Subbasin Staff Assessment

California State Water Resources Control Board (SWRCB) | October 14th, 2025

The Kaweah Subbasin is managed by three GSAs: East Kaweah GSA, Greater Kaweah GSA, and Mid-Kaweah GSA (collectively, the Kaweah GSAs or GSAs). Each GSA wrote their own GS

The Kaweah Subbasin is managed by three GSAs: East Kaweah GSA, Greater Kaweah GSA, and Mid-Kaweah GSA (collectively, the Kaweah GSAs or GSAs). Each GSA wrote their own GSP, East Kaweah GSP (EKGSP), Greater Kaweah GSP (GKGSP), and Mid-Kaweah GSP (MKGSP). The three GSPs are tied together by a coordination agreement. The primary use of groundwater within the subbasin is irrigated agriculture; in 2020, irrigated agriculture used more than 94 percent of the groundwater in the subbasin (2024 Coordination Agreement, Appendix 1, p. 27). The subbasin is critically overdrafted, which means that groundwater is pumped out of the subbasin faster than it is recharged by precipitation and other sources. On average, the amount pumped from the subbasin in a year is 104,000 acre-feet greater than the amount recharged (2024 GKGSP p. 1-1). Overdraft can cause the land surface to sink, potentially damaging infrastructure and reducing aquifer storage. In addition, overdraft threatens groundwater levels and drinking water quality and could have disparate impacts on communities that rely on shallower groundwater levels. Due to historic and political factors, many of these are economically disadvantaged and communities of color. As of 2022, the subbasin has an estimated population of 296,632 people with most of the population being Hispanic or Latino (60.6%) followed by white (31%) (American Community Survey, 2022). The average annual household income within the subbasin in 2022 is $71,000, which is significantly less than the state average of $91,551 (ibid.).