Evidence for faulting and fluid-driven earthquake processes from seismic attenuation variations beneath metropolitan Los Angeles

Nature Portfolio (Springer Nature) | July 30th, 2024

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.

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 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

Five-century record of climate and groundwater recharge variability in southern California

Nature Portfolio (Springer Nature) | December 3rd, 2019

Modifications to the rates of water flowing from the surface to groundwater (groundwater recharge) due to climate variability are the most difficult to assess because of

Modifications to the rates of water flowing from the surface to groundwater (groundwater recharge) due to climate variability are the most difficult to assess because of the lack of direct long-term observations. Here, we analyze the chloride salt distribution below the surface soil on a plateau near Los Angeles to reconstruct the amount of recharge that occurred in the last five centuries. Over this time interval, periods of major high and low recharge with different duration follow each other and this cyclicity is consistent with long-term atmospheric forcing patterns, such as the Pacific Decadal Oscillation. This study determines the range and the natural variability of recharge to groundwater, which sustains local freshwater flow system, and helps forecast future availability of groundwater resource in southern California, where water scarcity is critical to both local and global populations.

Flood-MAR Research and Data Development Plan

California Department of Water Resources (DWR) | October 31st, 2019

The Research Advisory Committee (RAC) is pleased to make this plan available to the growing network of farmers, researchers, planners, and water and land managers who wan

The Research Advisory Committee (RAC) is pleased to make this plan available to the growing network of farmers, researchers, planners, and water and land managers who want to expand our collective knowledge about using floodwaters for managed aquifer recharge (Flood-MAR). This plan outlines the priority information needed by those making management decisions about the where, when, and how of capturing available flood water to replenish California’s depleted aquifers.

Fluid migration pathways to groundwater in mature oil fields: Exploring the roles of water injection/production and oil-well integrity in California, USA

Science of The Total Environment (Elsevier) | August 23rd, 2023

Focused groundwater recharge in the Amargosa Desert basin

U.S. Geological Survey (USGS) | July 1st, 2007

 The Amargosa River is an approximately 300-kilometer-long regional drainage connecting the northern highlands on the Nevada Test Site in Nye County, Nev., to the floor

 The Amargosa River is an approximately 300-kilometer-long regional drainage connecting the northern highlands on the Nevada Test Site in Nye County, Nev., to the floor of Death Valley in Inyo County, Calif. Streamflow analysis indicates that the Amargosa Desert portion of the river is dry more than 98 percent of the time. Infiltration losses during ephemeral flows of the Amargosa River and Fortymile Wash provide the main sources of ground-water recharge on the desert-basin floor. The primary use of ground water is for irrigated agriculture. The current study examined ground-water recharge from ephemeral flows in the Amargosa River by using streamflow data and environmental tracers. The USGS streamflow-gaging station at Beatty, Nev., provided high-frequency data on base flow and storm runoff entering the basin during water years 1998–2001. Discharge into the basin during the four-year period totaled 3.03 million cubic meters, three quarters of which was base flow. Streambed temperature anomalies indicated the distribution of ephemeral flows and infiltration losses within the basin. Major storms that produced regional flow during the four-year period occurred in February 1998, during a strong El Niño that more than doubled annual precipitation, and in July 1999. The study also quantified recharge beneath undisturbed native vegetation and irrigation return flow beneath irrigated fields. Vertical profiles of water potential and environmental tracers in the unsaturated zone provided estimates of recharge beneath the river channel (0.04–0.09 meter per year) and irrigated fields (0.1–0.5 meter per year). Chloride mass-balance estimates indicate that 12–15 percent of channel infiltration becomes ground-water recharge, together with 9–22 percent of infiltrated irrigation. Profiles of potential and chloride beneath the dominant desert-shrub vegetation suggest that ground-water recharge has been negligible throughout most of the basin since at least the early Holocene. Surface-based electrical-resistivity imaging provided areal extension of borehole information from sampled profiles. These images indicate narrowly focused recharge beneath the Amargosa River channel, flanked by large tracts of recharge-free basin floor.

Forebay Aquifer Subbasin Groundwater Sustainability Plan

Salinas Valley Basin Groundwater Sustainability Agency | January 13th, 2022

The 2014 California Sustainable Groundwater Management Act (SGMA) requires that medium- and high-priority groundwater basins and subbasins develop Groundwater Sustainabil

The 2014 California Sustainable Groundwater Management Act (SGMA) requires that medium- and high-priority groundwater basins and subbasins develop Groundwater Sustainability Plans (GSPs) that outline how groundwater sustainably will first be maintained for 50 years. This GSP fulfills that requirement for the Salinas Valley—Forebay Aquifer Subbasin (Subbasin, or Forebay Subbasin), which is designated by the DWR as a medium priority groundwater subbasin. Plan approved by DWR 4/27/23.