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

Systems Analysis and Optimization of Local Water Supplies in Los Angeles

American Society of Civil Engineers (ASCE) | September 1st, 2017

Los Angeles, which relies on large infrastructure systems that import water over hundreds of miles, faces a future of reduced imports. Within Los Angeles and its hund

Los Angeles, which relies on large infrastructure systems that import water over hundreds of miles, faces a future of reduced imports. Within Los Angeles and its hundreds of water agencies, the capacity to adapt to future changes is influenced by laws, institutions, and hydrogeology. This paper presents a systems analysis of urban water management in metropolitan Los Angeles County to assess opportunities for increasing local water reliance. A network flow model was developed to investigate management tradeoffs across engineered, social, and environmental systems. With an aggressive regional demand target, increased stormwater capture (300%), and prioritized water reuse from existing facilities, imported water supplies can be cut by 30% while maintaining landscapes, economic productivity, and groundwater resources. Further reducing imports (by 40–50%) is possible through actions to promote additional reuse, recharge, conservation, and groundwater access. Reducing imported water without significant conservation results in likely groundwater overdraft. Fragmented networks of agencies in Los Angeles create an uneven landscape of vulnerability to water shortages. The paper discusses model applications, research needs, and policy implications of results for dry-climate cities.

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

Tehachapi-Cummings County Water District (TCCWD) v. Armstrong et al

Superior Court of California, County of Kern | February 25th, 1972

From An Evaluation of California’s Adjudicated Groundwater Basins by Langridge et al, UC Davis (2016): "Tehachapi Basin (1, 2) , Cummings Basin, and Brite Basin are

From An Evaluation of California’s Adjudicated Groundwater Basins by Langridge et al, UC Davis (2016): "Tehachapi Basin (1, 2) , Cummings Basin, and Brite Basin are three small groundwater basins in Kern County. Although the basins were adjudicated separately, a single entity, The Tehachapi-Cummings County Water District (TCCWD) serves as Watermaster over the three distinct groundwater basins. An interesting finding is that the Cummings adjudication was never completed. Because of this, its users rely on overlying rights with voluntary agreements, and there is no regulated curtailment of withdrawals. There are only a few big users so it is able to track its water use with relative accuracy, but the basin has significant overdraft. Two of its major users (Stallion Springs and Bear Valley) pump water from the basin that is delivered to offsite users, and they offset the export with imported water. Two-thirds of the residents within Cummings Basin are inmates at the California Correctional Institute."

Tehachapi-Cummings County Water District v. Austin et al

Superior Court of California, County of Kern | December 9th, 1970

Note from "An Evaluation of California’s Adjudicated Groundwater Basins" by Langridge et al: "Tehachapi Basin, Cummings Basin, and Brite Basin are three small ground

Note from "An Evaluation of California’s Adjudicated Groundwater Basins" by Langridge et al: "Tehachapi Basin, Cummings Basin, and Brite Basin are three small groundwater basins in Kern County. Although they were adjudicated as individual basins, the local Tehachapi-Cummings County Water District is the Watermaster for all three basins. Adjudication was deemed desirable so water users could tap into newly available imported water and also secure their water rights. To construct transmission facilities, a federal loan was needed, and adjudication was necessary to assure repayment."

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.

Temporal variability in irrigated land and climate influences on salinity loading across the Upper Colorado River Basin, 1986-2017

Environmental Research Letters (IOP) | January 19th, 2024

Temporary Restraining Order in Kings County Farm Bureau et al v. California State Water Resources Control Board

Superior Court of California, County of Kings | July 11th, 2024

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

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