Evaluation of Processes Affecting 1,2-Dibromo-3-Chloropropane (DBCP) Concentrations in Ground Water in the Eastern San Joaquin Valley, California: Analysis of Chemical Data and Ground-Water Flow and Transport Simulations

U.S. Geological Survey (USGS) | December 17th, 1999

Future use of the sole-source aquifer near Fresno in the eastern San Joaquin Valley, California, will depend, in part, on how long 1,2-dibromo-3-chloropropane (DB

Future use of the sole-source aquifer near Fresno in the eastern San Joaquin Valley, California, will depend, in part, on how long 1,2-dibromo-3-chloropropane (DBCP), an agricultural fumigant banned from use since the late 1970’s, persists at concentrations greater than the maximum contaminant level of 0.2 micrograms per liter (?g/L). Field data indicate that DBCP concentrations in ground water have decreased since the late 1970’s. Laboratory experiments by earlier investigators show that DBCP transformed to 2-bromoallyl alcohol (BAA) under conditions similar to in situ conditions, with an estimated half-life ranging from 6.1 (pH 7.8, 21.1 degrees Celsius) to 141 years (pH 7.0, 15 degrees Celsius). For this current study, a detailed hydrogeologic investigation was done to assess the relative importance of chemical transformation, dispersion, and ground-water pumping and reapplication of irrigation water in affecting DBCP concentrations. Groundwater samples were collected from 20 monitoring wells installed along a 4.6- kilometer transect. DBCP concentrations in these samples ranged from less than the detection limit of 0.03  g/L to a maximum of 6.4 g/L. Results of chlorofluorocarbon (CFC) age dating indicate that DBCP occurs in water that ranges in age from about 2 to 41 years. The primary transformation product BAA, which was identified during previous laboratory studies, was not detected at or greater than 0.03  g/L in any of the 20 ground- water samples. The lack of detection of BAA indicates that transformation to BAA is insignificant relative to other processes controlling DBCP concentrations. Results from this current study indicate that the in situ hydrolysis half-life for DBCP to BAA is much greater than the laboratory-determined values.

Executive Order N-7-23

State of California | May 17th, 2023

Exploring the Potential for Water-Limited Agriculture in the San Joaquin Valley

Public Policy Institute of California (PPIC) | July 21st, 2022

The rollout of California’s Sustainable Groundwater Management Act (SGMA) is altering the state’s agricultural landscape. As groundwater sustainability measures are

The rollout of California’s Sustainable Groundwater Management Act (SGMA) is altering the state’s agricultural landscape. As groundwater sustainability measures are implemented and water scarcity increases, at least half a million acres are projected to come out of irrigated production in the San Joaquin Valley, the state’s agricultural heartland. Rather than widespread land idling—which comes with unintended consequences such as dust, weeds, pests, and soil degradation — a switch from summer irrigated crops to winter crops produced with limited water (including winter cereals and forage crops, among others) might keep some of this land in production. Although water-limited agriculture faces large hurdles, some promising aspects warrant further exploration.

Exploring Water System Vulnerabilities in California's Central Valley Under the Late Renaissance Megadrought and Climate Change

American Geophysical Union (AGU) | April 24th, 2025

Fallowed agricultural lands dominate anthropogenic dust sources in California

Nature Portfolio (Springer Nature) | April 26th, 2025

Farmers Water District Groundwater Sustainability Plan Delta-Mendota Subbasin

Farmers Water District | January 1st, 2020

The Sustainable Groundwater Management Act (SGMA) was signed into law in 2014 for the purpose of protecting California’s groundwater resources. SGMA requires all high

The Sustainable Groundwater Management Act (SGMA) was signed into law in 2014 for the purpose of protecting California’s groundwater resources. SGMA requires all high and medium priority basins to develop Groundwater Sustainability Plans (GSP) to prevent overdraft and achieve sustainability in the utilization of groundwater resources. The Delta-Mendota Subbasin (Basin 5-022.07 in the California Department of Water Resources (DWR) Bulletin 118) (Subbasin) is a high priority Subbasin that has been assigned a critical overdraft designation by DWR. The Subbasin consists of 23 Groundwater Sustainability Agencies (GSA) who together created six individual GSA groups, each preparing a GSP in a coordinated manner as required by SGMA. Farmers Water District elected to form a GSA on June 14, 2016 in order to represent the interest of local landowners in the District in the development of a GSP with FWD designated as a Management Area in GSP. This GSP includes a description of groundwater conditions and basin settings of the Subbasin that is common to all six of the GSPs developed for the Delta-Mendota Subbasin in addition to describing the hydrogeologic conditions and management practices in the area of FWD. It also contains the steps that will be taken to achieve sustainability over the next 20 years by preventing undesirable results by monitoring for the following sustainability indicators as defined by SGMA: • Chronic Lowering of Groundwater Levels • Reduction in Groundwater Storage • Degraded Water Quality • Subsidence • Depletion of Interconnected Surface Water • Seawater Intrusion All but seawater intrusion applies to FWD, and each applicable sustainability indicator will be addressed in this GSP and is integrated into the Subbasin-wide and FWD monitoring program. Measurable objectives and minimum thresholds have been set for each sustainability indicator based on projected hydrologic conditions through the use of a numerical groundwater flow model. This GSP, in coordination with the five other GSPs for the Subbasin, will be implemented and result in the sustainable use of groundwater resources for all beneficial users in FWD and the Subbasin.

Farmers Water District Revised Groundwater Sustainability Plan Delta- Mendota Subbasin

Farmers Water District | July 18th, 2022

This work product is the Groundwater Sustainability Plan (GSP) for the Farmers Water District Groundwater Sustainability Agency (GSA). This GSP is one of six (6) individ

This work product is the Groundwater Sustainability Plan (GSP) for the Farmers Water District Groundwater Sustainability Agency (GSA). This GSP is one of six (6) individual GSPs being prepared for the Delta-Mendota Subbasin (DMS, Subbasin).

Faulting caused by groundwater level declines, San Joaquin Valley, California

Water Resources Research, American Geophysical Union | December 18th, 1980

Approximately 230 mm of aseismic vertical offset of the land surface across the Pond-Poso Creek fault in the San Joaquin Valley, California, probably is related to

Approximately 230 mm of aseismic vertical offset of the land surface across the Pond-Poso Creek fault in the San Joaquin Valley, California, probably is related to groundwater withdrawal for crop irrigation. The scarp is approximately 3.4 km long and occurs in an area where the land subsided more than 1.5 m from 1926 to 1970. Modern faulting postdates the beginning of water level declines and associated subsidence. Movement detected by precise leveling surveys from February 1977 to March 1979 was seasonal, occurring during periods of water level decline. Fault offset was greater in the year with the lower seasonal low water level. The modern movement probably is caused by localized differential compaction induced by differential water level declines across the preexisting fault.

Field-scale crop water consumption estimates reveal potential water savings in California agriculture

Nature Portfolio (Springer Nature) | March 25th, 2024

Final Amended Groundwater Sustainability Plan (GSP) Kern River Groundwater Sustainability Agency (KRGSA) Plan Area

Kern River Groundwater Sustainability Agency (KRGSA) | July 22nd, 2022

In January 2020, the Kern River Groundwater Sustainability Agency (KRGSA) submitted the original KRGSA Groundwater Sustainability Plan (GSP) to the Department of Water Re

In January 2020, the Kern River Groundwater Sustainability Agency (KRGSA) submitted the original KRGSA Groundwater Sustainability Plan (GSP) to the Department of Water Resources (DWR) in compliance with the Sustainable Groundwater Management Act (SGMA). The KRGSA GSP was one of five GSPs that were submitted through a Coordination Agreement to collectively cover the entire Kern County Subbasin. In January 2022, DWR sent a letter to the Kern County Subbasin GSAs that provided an evaluation of the Subbasin GPSs and determined that the GSPs were collectively “incomplete” in meeting all SGMA requirements (Determination Letter). DWR noted three separate deficiencies in the collective GSPs and provided Corrective Actions to address the deficiencies. This Amended KRGSA GSP has been prepared to supplement the original 2020 KRGSA GSP in response to DWR comments. Amended sections are incorporated into the original KRGSA GSP to produce one complete document. Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7