Turlock Subbasin Groundwater Sustainability Plan (Revised)

West and East Turlock Subbasin Groundwater Sustainability Agencies | July 12th, 2024

The Turlock GSAs submitted the first version of the Turlock GSP to the Department of Water Resources (DWR) in January 2022. DWR determined the GSP to be incomplete in J

The Turlock GSAs submitted the first version of the Turlock GSP to the Department of Water Resources (DWR) in January 2022. DWR determined the GSP to be incomplete in January of 2024 (DWR, 2024) and identified two deficiencies. The first of these involves provision of sufficient information (namely, analysis of potential impacts on wells) to support the selection of sustainable management criteria for chronic lowering of groundwater levels. The second involves the provision of sufficient details on the projects and management actions to mitigate overdraft in the Subbasin and to provide a feasible path to achieve sustainability. Corrective actions are incorporated into this revised July 16, 2024 GSP for resubmittal to DWR. This does not represent a GSP update, which is slated for 2027. The revised GSP was adopted by the GSAs on July 11, 2024 pursuant to 23 CCR § 355.2(e)(2)(A).

Twenty-first Annual Report of the Mojave Basin Area Watermaster

Mojave Basin Area Watermaster | May 1st, 2015

Two-dimensional and three-dimensional digital flow models of the Salinas Valley ground-water basin, California

U.S. Geological Survey (USGS) | November 16th, 1978

The Salinas Valley is a topographic and ground-water basin in central coastal California. The ground-water basin extends from Monterey Bay south­eastward along the Salin

The Salinas Valley is a topographic and ground-water basin in central coastal California. The ground-water basin extends from Monterey Bay south­eastward along the Salinas River to San Arda, a distance of 70 miles, and has a maximum thickness of 2,000 feet. Annual recharge to the ground-water basin, which is derived mostly from the Salinas River, is about 290,000 acre­feet. Annual discharge, which is mostly from pumpage but also includes the consumptive use of ground water by riparian vegetation along the Salinas River, is about 507,000 acre-feet. About 45 percent of the pumpage, or 217,000 acre-feet of water annually, returns to the ground-water system. A group of interacting hydrologic models was developed for the Salinas Valley. These models include the small-stream model, river model, two­dimensional ground-water model, and three-dimensional ground-water model. The small-stream model simulates ground-water recharge from small streams that are tributary to the Salinas River. The river model simulates ground­water recharge from and surface-water discharge in the Salinas River. The two-dimensional and three-dimensional ground-water models simulate hydraulic head in the ground-water basin. The ground-water models were calibrated by comparing water level com­puted by the models to the corresponding measured water level for both steady-state and transient-state simulations. For the steady-state simulation, which was used to calibrate transmissivity for the two-dimensional model and hydraulic conductivity for the three-dimensional model, the median deviation of the model-generated water level from measured water level was 6 and 5 feet for the two-dimensional and three-dimensional models, respectively. For the transient-state simulation, which was used to calibrate storage coefficient for the two-dimensional model and specific storage for the three-dimensional model, the median deviation of the model-generated water level (at the end of a 3-year calibration period) from measured water level was 6 feet for both models.

UC groundwater research: A survey

California Agriculture (UCANR) | March 13th, 2018

As California implements the Sustainable Groundwater Management Act (SGMA), UC research is building knowledge and supporting innovation in groundwater recharge, groundwat

As California implements the Sustainable Groundwater Management Act (SGMA), UC research is building knowledge and supporting innovation in groundwater recharge, groundwater accounting, groundwater quality, groundwater governance and more. Here's a sample of work from across the UC system: whole watershed accounting; water availability for recharge; precision data on snowmelt; spatial data on well vulnerability; large scale groundwater recharge and agricultural systems; groundwater-surface water interactions; groundwater quality and salinity; water supply, land use and rural communities; data on water use and water rights; managed aquifer recharge on farmland; soil suitability for recharge; distributed stormwater collection; net metering for groundwater; geophysical imaging; groundwater governance; lessons on groundwater permitting from around the West; supporting Groundwater Sustainability Plan development; the economics of sustainable groundwater management; and considerations for groundwater markets.

Ukiah Valley Groundwater Sustainability Plan

Ukiah Valley Groundwater Sustainability Agency (UVGSA) | January 12th, 2022

The Sustainable Groundwater Management Act (SGMA), passed by the California legislature in 2014, requires local entities to jointly assess groundwater conditions in thei

The Sustainable Groundwater Management Act (SGMA), passed by the California legislature in 2014, requires local entities to jointly assess groundwater conditions in their local areas and to develop a Groundwater Sustainability Plan (GSP) by a specified deadline to ensure that sustainable conditions are achieved within 20 years of GSP adoption. An effective and efficient groundwater management plan is critical for the local economy and the health and welfare of the people, the environment, and all other beneficial uses and users of groundwater in a local area. The Ukiah Valley Basin (Basin) is a medium-priority groundwater basin located in Mendocino County. The sole Groundwater Sustainability Agency for the Basin is the Ukiah Valley Groundwater Sustainability Agency (UVBGSA or GSA). The GSA consists of the following local agencies: the County of Mendocino (County), the City of Ukiah (City), the Upper Russian River Water Agency (URRWA), and the Russian River Flood Control and Water Conservation and Improvement District (RRFC). The GSA applied for and was awarded Proposition 1 and Proposition 68 grant funds to develop the GSP and meet the SGMA-mandated schedule for submitting a GSA-approved GSP to the California Department of Water Resources (DWR) by January 31, 2022. GSA will be funded through member agency contributions during the first 5-year implementation period until a fee structure is implemented to support and fund GSA activities. Additional funding opportunities will continue to be explored, including grants. In late-2022, DWR will open round 2 solicitations under the SGMA Grant Program, which will provide approximately $204 million to high and medium priority subbasins to implement the GSP and its projects and management actions. A variety of local interests are represented by the GSA and served on the technical advisory committee (TAC), including municipal-residential water users, agricultural water users, public water systems, local land use planning agencies, environmental users, surface water users, tribal governments, disadvantaged communities, groundwater monitoring and reporting entities, holders of overlying groundwater rights, adjacent Basins, industrial users, commercial users, remediation pumpers, natural ecosystems, and the general public. Many of these local entities have a long history with groundwater and surface water management in the Basin and are well equipped to perform SGMA-required planning functions. The GSA, TAC members, and the public have undertaken a thorough and timely review of past, current, and projected future water resources needs and groundwater conditions to meet SGMA requirements for GSP development. Throughout the development of the GSP, regular communication and engagement activities were conducted to inform and receive input from local stakeholders and the public. The GSP includes a comprehensive groundwater basin description, which was used to develop a regional integrated hydrological model that quantifies current water budgets and projects future conditions of the Basin. The GSP also includes an assessment of the impacts of predicted future groundwater levels on beneficial users, including groundwater-dependent ecosystems, shallow wells, and interconnected surface water using the best available data and science available. Importantly, these assessments are used to develop measurable sustainable management criteria that avoid significant and unreasonable impacts to these beneficial users, and that can be monitored and adjusted throughout plan implementation. The key finding of the GSP, based on a thorough analysis of the best available information, is that the Basin will be sustainable over the next twenty years if planned projects and management actions (PMAs) are implemented as needed with respect to climate change and changes in the water system. These PMAs will help maintain groundwater levels and storage volumes and protect ecosystems, interconnected surface water, and shallow wells. Potential climate change impacts are not fully understood at this stage due to data gaps and the need for additional modeling and data collection. The GSP will implement a more comprehensive data collection that improves modeling capabilities and can provide a better assessment of climate change impacts in the future. The proposed PMAs will promote adaptive management practices and long-term resiliency to varying climatic conditions, such as more frequent, longer-lasting, and more intense droughts and less frequent and wetter winters. As described in Chapter 2, the sustainable yield for the entire Basin is estimated to be at least 6,500 acre-feet, based on historical, average groundwater pumping. The sustainable yield of the Basin is defined based on avoidance of undesirable results. Because the Basin is not overdrafted and the historical pumping average may not represent the actual sustainability yield of the Basin. A groundwater monitoring network comprised of selected wells will be used to track groundwater levels and groundwater quality. Sustainable management criteria set at representative monitoring wells in the network will be implemented to gage these conditions over time and ensure that groundwater levels and quality remain within a range that avoids significant and unreasonable impacts to beneficial uses and users of groundwater. Streamflow measurements are added to the monitoring network to measure surface water depletion due to groundwater pumping in combination with groundwater level measurements and integrated hydrological modeling simulations. Monitoring and data collection efforts will continue through the first five years of GSP implementation to further identify and prioritize project and management actions. Once approved by the GSA, the activities identified throughout the GSP development process will be implemented, including: • Ongoing monitoring and annual reporting on conditions in the Basin; • Ongoing public engagement and outreach; • Coordination within the watershed and with neighboring basins and water management entities; • Development and implementation of a shallow well protection and monitoring program; • Coordination with land use agencies and water supply agencies to promote consistency with the GSP; • Coordination with regional agencies in the development of updated climate change projections; • Implementing PMAs as deemed needed by the GSA to maintain and promote sustainability of the Basin; and, • Preparation of five-year updates to the GSP starting in 2027. Due to file size, the GSP is divided into separate files. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6  

Unanswered questions for implementation of the Sustainable Groundwater Management Act

California Agriculture (UCANR) | August 24th, 2016

California is grappling with the implications of the Sustainable Groundwater Management Act (SGMA), a visionary and potentially revolutionary law that could profoundly ch

California is grappling with the implications of the Sustainable Groundwater Management Act (SGMA), a visionary and potentially revolutionary law that could profoundly change the way water is managed in the state. The nature of the revolution, however, is not yet clear. Whether and how SGMA achieves its goals hinges on open questions about its implementation.  

Unprecedented continental drying, shrinking freshwater availability, and increasing land contributions to sea level rise

American Association for the Advancement of Science (AAAS) | July 25th, 2025

Changes in terrestrial water storage (TWS) are a critical indicator of freshwater availability. We use NASA GRACE/GRACE- FO data to show that the continents have undergon

Changes in terrestrial water storage (TWS) are a critical indicator of freshwater availability. We use NASA GRACE/GRACE- FO data to show that the continents have undergone unprecedented TWS loss since 2002. Areas experiencing drying increased by twice the size of California annually, creating “mega-drying” regions across the Northern Hemisphere. While most of the world’s dry/wet areas continue to get drier/wetter, dry areas are now drying faster than wet areas are wetting. Changes in TWS are driven by high-latitude water losses, intense Central American/European droughts, and groundwater depletion, which accounts for 68% of TWS loss over non-glaciated continental regions. “Continental drying” is having profound global impacts. Since 2002, 75% of the population lives in 101 countries that have been losing freshwater water. Furthermore, the continents now contribute more freshwater to sea level rise than the ice sheets, and drying regions now contribute more than land glaciers and ice caps. Urgent action is required to prepare for the major impacts of results presented

Unwatering the Comstock Lode

Scientific American | November 4th, 1899

AN operation of immense interest to miners and mining generally has been in progress for the past five months in Nevada, in the district embracing the well known Comsto

AN operation of immense interest to miners and mining generally has been in progress for the past five months in Nevada, in the district embracing the well known Comstock mines. The remarkable circumstances connected with the discovery and development of the wonderful lode upon which these famous mines are located is a matter of comparatively recent history—too recent to require more than a passing reference. The wild speculation, which followed their discovery, forms one of the most thrilling pages of the annals of the Far West. It is estimated that up to the year 1886 the assay value of the gold and silver extracted from these mines amounted to $500.000,000. It was during this period of greatest production that the race of California multi-millionaires arose. Up to 1886 the exploration of all the territory embraced in the Comstock lode was industriously pursued, one shaft reaching a depth of 3,300 feet, but the exhaustion of ore bodies of high grade and the large expense attending milling and mining together with the heavy tax necessary in controlling the enormous volumes of water which every where flowed from the ground caused an abandonment of all mining below the 1,600-foot level. Another element of difficulty was the high temperatures experienced on the deeper levels, which increased as the shafts were lowered until miners were able only to work in shifts of a few moments in length. In a few months the water arose to within 1,640 feet of the surface opening of the Consolidated California and Virginia shaft, and at that level it has remained for nearly thirteen years. Above this level mining has been prosecuted with some success since the lower levels were flooded, and it is now believed that all pay ore bodies above the 1,600-foot level are practically exhausted.

Update on an Analysis of a Potential Groundwater Storage and Recovery Program in the Carpinteria Groundwater Basin

Montecito Water District (MWD) | March 11th, 2025

Updated Groundwater Sustainability Plan, San Joaquin Valley – Tule, Alpaugh Groundwater Sustainability Agency

Alpaugh Groundwater Sustainability Agency | July 27th, 2022

Alpaugh GSA is part of the Tule Subbasin and was formed in May 2016 for the purpose of complying with the SGMA. This updated GSP complies with the SGMA by addressing the

Alpaugh GSA is part of the Tule Subbasin and was formed in May 2016 for the purpose of complying with the SGMA. This updated GSP complies with the SGMA by addressing the DWR GSP Emergency Regulations in § 354.2 through 354.10. The GSP is the result of a collaborative process between local water agencies, technical experts, environmental managers, and community members with a mutual goal of sustainably managing the groundwater basin. Alpaugh GSA is one of seven participating GSAs in the Tule Subbasin, which organize their activities through the updated Tule Subbasin Coordination Agreement (Coordination Agreement). Due to size this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5