Extreme hydrological changes in the southwestern US drive reductions in water supply to Southern California by mid century

Environmental Research Letters (IOP) | September 21st, 2016

The Southwestern United States has a greater vulnerability to climate change impacts on water security due to a reliance on snowmelt driven imported water. The State of C

The Southwestern United States has a greater vulnerability to climate change impacts on water security due to a reliance on snowmelt driven imported water. The State of California, which is the most populous and agriculturally productive in the United States, depends on an extensive arti cial water storage and conveyance system primarily for irrigated agriculture, municipal and industrial supply and hydropower generation. Here we take an integrative high-resolution ensemble modeling approach to examine near term climate change impacts on all imported and local sources of water supply to Southern California. While annual precipitation is projected to remain the same or slightly increase, rising temperatures result in a shift towards more rainfall, reduced cold season snowpack and earlier snowmelt. Associated with these hydrological changes are substantial increases in the frequency and the intensity of both drier conditions and ooding events. The 50 year extreme daily maximum precipitation and runoff events are 1.5–6 times more likely to occur depending on the water supply basin. Simultaneously, a clear de cit in total annual runoff over mountainous snow generating regions like the Sierra Nevada is projected. On one hand, the greater probability of drought decreases imported water supply availability. On the other hand, earlier snowmelt and signicantly stronger winter precipitation events pose increased flood risk requiring water releases from control reservoirs, which may potentially decrease water availability outside of the wet season. Lack of timely local water resource expansion coupled with projected climate changes and population increases may leave the area in extended periods of shortages.

Factors Affecting Public-Supply-Well Vulnerability to Contamination: Understanding Observed Water Quality and Anticipating Future Water Quality

U.S. Geological Survey (USGS) | May 14th, 2013

As part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program, a study was conducted from 2001 to 2011 to shed light on factors that affect the

As part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program, a study was conducted from 2001 to 2011 to shed light on factors that affect the vulnerability of water from public-supply wells to contamination (referred to hereafter as “public-supply-well vulnerability”). The study was designed as a follow-up to earlier NAWQA studies that found mixtures of contaminants at low concentrations in groundwater near the water table in urban areas across the Nation and, less frequently, in deeper groundwater typically used for public supply. Beside the factors affecting public-supply-well vulnerability to contamination, this circular describes measures that can be used to determine which factor (or factors) plays a dominant role at an individual public-supply well. Case-study examples are used throughout to show how such information can be used to improve water quality. In general, the vulnerability of the water from public-supply wells to contamination is a function of contaminant input within the area that contributes water to a well, the mobility and persistence of a contaminant once released to the groundwater, and the ease of groundwater and contaminant movement from the point of recharge to the open interval of a well. The following measures described in this circular are particularly useful for indicating which contaminants in an aquifer might reach an individual public-supply well and when, how, and at what concentration they might arrive: Sources of recharge—Information on the sources of recharge for a well provides insight into contaminants that might enter the aquifer with the recharge water and potentially reach the well. Geochemical conditions—Information on the geochemical conditions encountered by groundwater traveling to a well provides insight into contaminants that might persist in the water all the way to the well. Groundwater-age mixtures—Information on the ages of the different waters that mix in a well provides insight into the time lag between contaminant input at the water table and contaminant arrival at the well. It also provides insight into the potential for in-well dilution of contaminated water by unaffected groundwater of a different age that simultaneously enters the well. Preferential flow pathways—pathways that provide little resistance to flow—can influence how all other factors affect public-supply-well vulnerability to contamination. For example, preferential flow pathways can influence whether a contaminant source is physically linked to a well, whether contaminant concentrations are substantially altered before contaminated groundwater reaches a well, and whether contaminated groundwater can arrive at a well within a timeframe of concern to the well owner. Methods for recognizing the influence of preferential flow pathways on the quality of water from a public-supply well are presented in this circular and can provide opportunities to prevent or mitigate the deterioration of a water supply. Knowing what water-quality variables to measure, what spatial and temporal scales on which to measure them, and how to interpret the resulting data makes it possible for samples from public-supply wells to provide a broad window into a well’s past and present water quality—and possibly future water quality. Such insight can enable resource managers to prioritize actions for sustaining a high-quality groundwater source of drinking water.

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.

Fillmore Basin Groundwater Sustainability Plan

Fillmore and Piru Basins Groundwater Sustainability Agency | December 16th, 2021

The Fillmore Basin (the Basin) is managed (along with the upslope Piru Basin) by the Fillmore and Piru Basins Groundwater Sustainability Agency (the Agency). The Basin is

The Fillmore Basin (the Basin) is managed (along with the upslope Piru Basin) by the Fillmore and Piru Basins Groundwater Sustainability Agency (the Agency). The Basin is planned to remain sustainable over the Sustainable Groundwater Management Act (SGMA) implementation and sustainability period based on the current understanding of historical, current (2019), and projected (2022 through 2072) groundwater conditions in relation to the sustainability indicators specified in SGMA. A sustainability indicator refers to any of the effects caused by groundwater conditions occurring throughout the basin that, when significant and unreasonable, cause undesirable results. The Agency, with consideration of feedback from active stakeholder engagement, has identified and planned for the prevention of significant and unreasonable undesirable results.

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

Final Environmental Impact Report Volume II: Revised Draft EIR Comprehensive Groundwater Cleanup Strategy for Historical Chromium Discharges from PG&E’s Hinkley Compressor Station, San Bernardino County

California State Water Resources Control Board (SWRCB) | April 20th, 2013

Click here for Volume I.

Click here for Volume I.

Final Groundwater Assessment Study: A Status Report on the Use of Groundwater in the Service Area of the Metropolitan Water District of Southern California

Metropolitan Water District of Southern California (MWD) | September 3rd, 2007

Final Groundwater Sustainability Plan for the Yucaipa Groundwater Subbasin

San Bernardino Valley Municipal Water District | January 27th, 2022

The Yucaipa Groundwater Sustainability Agency (GSA), acting as the GSA for the Yucaipa Subbasin (Plan Area, Subbasin), developed this Groundwater Sustainability Plan (GS

The Yucaipa Groundwater Sustainability Agency (GSA), acting as the GSA for the Yucaipa Subbasin (Plan Area, Subbasin), developed this Groundwater Sustainability Plan (GSP) in compliance with the 2014 Sustainable Groundwater Management Act (SGMA) and the California Department of Water Resources (DWR) GSP Regulations. The Yucaipa Subbasin lies within the Upper Santa Ana River Basin Hydrologic Region (DWR Basin Number 8-002.07) and underlies an area of approximately 25,300 acres under portions of the cities of Calimesa, Redlands, and Yucaipa, as well as unincorporated San Bernardino and Riverside Counties. DWR designated the Yucaipa Subbasin a high priority basin based primarily on its reliance on groundwater for water supply. However, this Subbasin is not in a state of critical overdraft. Under SGMA, GSAs “have the responsibility for adopting a Plan that defines the basin setting and establishes criteria that will maintain or achieve sustainable groundwater management.” The requirement of the GSP is to maintain or achieve sustainable groundwater management in the Yucaipa Subbasin by 2042. Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6