Subsurface water flux in California's Central Valley and its source watershed from space geodesy

American Geophysical Union (AGU) | September 29th, 2022

We combine measurements from Global Positioning System positioning and Gravity Recovery and Climate Experiment gravity to infer change in water components in Central Vall

We combine measurements from Global Positioning System positioning and Gravity Recovery and Climate Experiment gravity to infer change in water components in Central Valley and its source watershed, the Sacramento-San Joaquin-Tulare River basin better than possible with either technique separately. We find that the Central Valley has lost groundwater from 2006 to 2021 at 2.2 ± 0.7 km 3/ yr (95% confidence limits follow the “±” sign), with 2/3 of the groundwater loss occurring in the southern part of the Valley. We estimate the seasonal recharge and loss of subsurface water in the Central Valley. Comparison to a model accounting for precipitation, evapotranspiration, and river water entering and leaving the Central Valley suggests that deep groundwater may be flowing from the Sierra Nevada mountains into the Central Valley.

Sustainable Groundwater Management: What We Can Learn from California’s Central Valley Streams

Nature Conservancy | June 13th, 2014

Groundwater is intimately connected to surface water, which has profound implications for sustainable water resource management. California has historically overlooked th

Groundwater is intimately connected to surface water, which has profound implications for sustainable water resource management. California has historically overlooked this important interaction and as a consequence, decisions about groundwater extractions have generally failed to address the resulting impacts to surface flows and aquatic ecosystems such as rivers, wetlands and springs. This has contributed to a loss of approximately 95 percent of the historical wetlands and river habitat in California’s Central Valley. With the passage of the Sustainable Groundwater Management Act (SGMA), groundwater sustainability agencies across the state will soon be required to manage groundwater resources to avoid causing undesirable results to groundwater levels and interconnected groundwater and surface water. These groundwater levels and areas of interconnection support groundwater- dependent ecosystems2 (GDEs). Therefore, an important first step in sustainable groundwater management is to understand how groundwater pumping impacts surface water, including streams, and GDEs.

Sustainable Water Management Strategy for Specialty Crop Expansion in the Sacramento Valley

Sacramento Area Council of Governments (SACOG) | June 26th, 2018

The Sacramento Area Council of Governments (SACOG) is an association of local governments in the six-county Sacramento Region of El Dorado, Placer, Sacramento, Sutter, Yo

The Sacramento Area Council of Governments (SACOG) is an association of local governments in the six-county Sacramento Region of El Dorado, Placer, Sacramento, Sutter, Yolo, and Yuba counties (excluding the Tahoe Basin in Placer and El Dorado counties) and the 22 cities therein. SACOG provides planning and funding for the region and serves as a forum for the study and resolution of regional issues. SACOG prepares the region’s long range plan which considers both transportation and land use. Through the lens of rural planning, SACOG has actively engaged in a Rural-Urban Connections Strategy (RUCS) Program that has studied ways to enhance rural economies and natural assets. The RUCS Program includes a scenario analysis modeling tool that links a parcel-level crop map with environmental and economic factors, including a comprehensive profile of per acre operational cost and return metrics for each crop. The study described in this report looks at how new agricultural crops and markets coupled with improved irrigation techniques will support new specialty crop acreage in the SACOG area. While new and improved irrigation techniques can result in better crop yields and decreased water demands, increases in irrigation efficiency also result in reduced groundwater recharge from irrigation return flows. SACOG received grant funding from the California Department of Food and Agriculture (CDFA) to evaluate the feasibility of recharging groundwater on agricultural lands within the SACOG portion of the Sacramento Valley to benefit specialty crop production. The primary goal of the project is to bring together a broad range of different factors impacting groundwater recharge and infiltration and to identify areas across the region that are most suited for strategic flooding of specialty crop fields; in other words, areas that will most efficiently and effectively facilitate recharge, while minimizing cost to the specialty crop producer. Ultimately, this feasibility information will be incorporated into SACOG’s RUCS model to evaluate the potential benefits of recharging groundwater on agricultural land for the benefit of specialty crops.

Sutter County Groundwater Management Plan

Sutter County | March 19th, 2012

Sutter County intends this GMP to be relevant for the entire County. Sutter County overlies the south central part of the Sacramento Valley Groundwater Basin, and specif

Sutter County intends this GMP to be relevant for the entire County. Sutter County overlies the south central part of the Sacramento Valley Groundwater Basin, and specifically the Sutter Subbasin and portions of the East Butte and North American Subbasins. The majority of the County is serviced by water and irrigation districts, reclamation districts, cities, and public utility districts, which have the authority to manage groundwater in their service areas. Unless those entities decline to manage groundwater on their own, and instead enter into agreements with the County, this GMP does not formally apply to those areas. If those entities choose not to adopt their own GMPs, they have the option of taking formal action to adopt the Sutter County GMP for their areas. By doing so, they will fulfill the requirements of the groundwater management provisions of the California Water Code.

Sutter Subbasin Groundwater Sustainability Plan

Sutter County | January 28th, 2022

With a 20-year implementation period and a 50-year planning horizon, the Sutter Subbasin GSP is considered to be a “living” document. The Sutter Subbasin Groundwater

With a 20-year implementation period and a 50-year planning horizon, the Sutter Subbasin GSP is considered to be a “living” document. The Sutter Subbasin Groundwater Sustainability Agencies (GSAs) will implement this GSP using adaptive management strategies to respond to challenges related to groundwater sustainability, including monitoring of conditions in the Subbasin according to a prescribed schedule and implementing projects and management actions (PMAs). Conditions will be evaluated on an annual basis (or more frequently, as warranted) utilizing monitoring data collected as part of this GSP, as well as other publicly available sources, and PMAs will be added or revised in the GSP annual reports. During five-year GSP evaluations, the GSP will also be reviewed and revised, as needed, as more is known about the effects of current and future conditions. Due to size, this file has been divided into three parts. Part 1, Part 2, Part 3

Talbert Seawater Intrusion Barrier Operations & Maintenance Manual

Orange County Water District (OCWD) | March 15th, 2023

OCWD’s Talbert Seawater Barrier (Talbert Barrier, Barrier) has been in operation since 1976. Since 1976 the Barrier has undergone many changes including new well design

OCWD’s Talbert Seawater Barrier (Talbert Barrier, Barrier) has been in operation since 1976. Since 1976 the Barrier has undergone many changes including new well designs and improved injection water quality. Since 2008, the Talbert Barrier has been injecting advanced treated wastewater from OCWD’s GWRS treatment plant. This manual will examine in detail the various types of injection wells, their operational procedures and the procedures followed to monitor the quality of the injection water and evaluate injection well performance. Due to size, this document has been divided. Part 1, Part 2

Temescal Basin Groundwater Sustainability Plan

Temescal Basin Groundwater Sustainability Agency | January 27th, 2022

Wishing to provide a framework for cooperative groundwater management and SGMA compliance, the City of Corona (Corona), City of Norco (Norco), and the Home Gardens Coun

Wishing to provide a framework for cooperative groundwater management and SGMA compliance, the City of Corona (Corona), City of Norco (Norco), and the Home Gardens County Water District (HGCWD) executed a Memorandum of Understanding (MOU) in March 2017 establishing the Temescal Basin Groundwater Sustainability Agency (Temescal GSA). In August 2017, the Temescal GSA became the GSA for the Basin by submitting a formation notice to DWR. While Corona is leading this effort, the GSP will be developed jointly among the three agencies, with coordinated implementation toward sustainable management. Due to size, the file has been divided into four parts. Part 1, Part 2, Part 3, Part 4

Temporal and Spatial Patterns of Groundwater Recharge Across a Small Watershed in the California Sierra Nevada Mountains

Frontiers in Water (Frontiers) | May 17th, 2022

Mountain-block groundwater recharge is a crucial freshwater source in arid to semiarid watersheds worldwide; yet its quantification is difficult due to (1) hydrogeologica

Mountain-block groundwater recharge is a crucial freshwater source in arid to semiarid watersheds worldwide; yet its quantification is difficult due to (1) hydrogeological heterogeneities especially in bedrock-dominated regimes, (2) drastic altitudinal ranges in climate, land use and land cover, and (3) mixing with deep groundwater derived from adjacent basins (i.e., interbasin groundwater flow). In this study, we test the utility of soil water-balance (SWB) modeling to quantify mountain-block groundwater recharge in the South Fork Tule River watershed in the California Sierra Nevada Mountains. This 1,018 km2 watershed is instrumented with 3 USGS stream gages that allow for the development of a refined recharge (i.e., baseflow) calibration dataset via multi-objective optimization-based hydrograph separation. The SWB model was used to compute groundwater recharge and other water balance components at a daily time step using a 30-m grid cell size for a 40-year (1980–2019) study period. Mean annual recharge and runoff were estimated at 3.7 in/yr (3.0 m3/s) and 1.4 in/yr (1.2 m3/s), respectively, with modified Nash Sutcliffe Efficiency indices of 0.61 between baseflow and SWB-derived recharge, and 0.90 between hydrograph separation- and SWB-derived runoff. There is a strong correlation between annual recharge and rainfall (Pearson R = 0.95, p < 0.001) which attests to short residence times in the unsaturated zone and the immediate impact of droughts in 1990, 1999, and 2013. However, results of a modified Mann-Kendall trend analysis indicate no directional trends in recharge or runoff throughout the study period. Parameter sensitivity analyses reveal a persistent overprediction of recharge over baseflow that is particularly pronounced in the upper reaches of the watershed. This is likely related to the SWB model only considering soil characteristics at the surface and not simulating the fate of potential recharge below the root zone where it may be impeded from reaching the aquifer by shallow, impermeable bedrock. This limitation should be considered carefully for future water supply projections in this and comparable bedrock-dominated settings.

Tentative Ruling, Friant Water Authority vs. Eastern Tule Groundwater Sustainability Agency

Superior Court of California, County of Tulare | June 25th, 2024

Testing the Established Hydrogeologic Model of Source Water to the Amargosa River Basin, Inyo and San Bernardino Counties, California

Environmental Forensics (Taylor & Francis) | November 15th, 2015

The current conceptual hydrogeologic model established for source water to the Amargosa River was tested in order to help inform management decisions regarding the Amargo

The current conceptual hydrogeologic model established for source water to the Amargosa River was tested in order to help inform management decisions regarding the Amargosa River's Federal designation as Wild and Scenic through an Act of Congress. The limited availability of water in this region results in the critical need for effective management in the basin to maintain its Wild and Scenic attributes inclusive of habitat for several endangered and threatened species. The use of forensic tools and integration of multiple lines of geologic, hydrogeologic, geochemical, and stable isotopic evidence suggest that the simple historical model for primary groundwater transport through this region is incorrect and that a large supply of regional baseflow does not provide the hydrogeological foundation of the Amargosa River basin. Data collected is consistent with an alternative model requiring complex source mixing and shallow alluvial groundwater that supports river flow. This conclusion also suggests Wild and Scenic conditions in this basin are more precarious than previously understood.