Simulations of Ground-Water Flow and Particle Pathline Analysis in the Zone of Contribution of a Public-Supply Well in Modesto, Eastern San Joaquin Valley, California

U.S. Geological Survey (USGS) | July 1st, 2008

Siskiyou County Agricultural Economics Analysis Considering Groundwater Regulation

University of California, Merced | September 2nd, 2021

This economic analysis estimates potential impacts in gross revenues from changing cropping patterns in Siskiyou County’s three agricultural valleys namely Butte Valle

This economic analysis estimates potential impacts in gross revenues from changing cropping patterns in Siskiyou County’s three agricultural valleys namely Butte Valley (Butte), Scott River Valley (Scott), and Shasta Valley (Shasta). This analysis provides insight on economic costs of benefits of land and water use decisions, while identifying areas that may benefit from intervention and stakeholder processes.

Soil and Groundwater Contamination: Nonaqueous Phase Liquids–Principles and Observations

American Geophysical Union (AGU) | January 1st, 2005

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 17. Nonaqueous phase liquids (NAPLs) are frequently found as soil a

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 17. Nonaqueous phase liquids (NAPLs) are frequently found as soil and groundwater contaminants. Highly toxic even in small volumes, NAPLs can pose a threat to human health and damage surface and subsurface ecosystems. In this book, we clarify the complex phenomena of NAPL migration and offer insight into the behavior of NAPLs at sites undergoing monitoring and remediation. Contents include discussion on: * Principles of NAPL behavior in the subsurface, including flow, transfer of components to water and gas phases, and transport * Migration and distribution * Site characterization and monitoring * Remediation methods, including hydraulic removal, pump and treat, and soil vapor extraction * Further discussion on gaps in our understanding of NAPLs at the field scale along with a thorough tutorial approach and supplemental CD, make this book an important guide and resource for practicing engineers and scientists, risk assessment professionals, teachers, and students.

Soil suitability index identifies potential areas for groundwater banking on agricultural lands

California Agriculture (UCANR) | ?

Groundwater pumping chronically exceeds natural recharge in many agricultural regions in California. A common method of recharging groundwater — when surface

Groundwater pumping chronically exceeds natural recharge in many agricultural regions in California. A common method of recharging groundwater — when surface water is available — is to deliberately flood an open area, allowing water to percolate into an aquifer. However, open land suitable for this type of recharge is scarce. Flooding agricultural land during fallow or dormant periods has the potential to increase groundwater recharge substantially, but this approach has not been well studied. Using data on soils, topography and crop type, we developed a spatially explicit index of the suitability for groundwater recharge of land in all agricultural regions in California. We identified 3.6 million acres of agricultural land statewide as having Excellent or Good potential for groundwater recharge. The index provides preliminary guidance about the locations where groundwater recharge on agricultural land is likely to be feasible. A variety of institutional, infrastructure and other issues must also be addressed before this practice can be implemented widely.

Solano Subbasin Groundwater Sustainability Plan

Solano Subbasin GSA Collaborative | November 30th, 2021

The Sustainable Groundwater Management Act (SGMA) encourages groundwater management at the local level. Local entities are responsible for forming Groundwater Sustainabil

The Sustainable Groundwater Management Act (SGMA) encourages groundwater management at the local level. Local entities are responsible for forming Groundwater Sustainability Agencies (GSAs) to develop and implement Groundwater Sustainability Plans (GSPs) to guide sustainable management of groundwater basins or subbasins identified as high or medium priority by the State. Five GSAs in the Solano Subbasin organized to form the Solano Collaborative to develop a single GSP for the Subbasin: Solano Subbasin GSA, Solano Irrigation District GSA, City of Vacaville GSA, Northern Delta GSA, and Sacramento County GSA. The Solano Collaborative together with five other GSAs have adopted the Solano Subbasin Groundwater Sustainability Plan.

Solar Energy and Groundwater in the San Joaquin Valley

Public Policy Institute of California (PPIC) | October 26th, 2022

The Sustainable Groundwater Management Act (SGMA) requires groundwater users to bring their basins into balance over the next two decades. In the San Joaquin Valley, this

The Sustainable Groundwater Management Act (SGMA) requires groundwater users to bring their basins into balance over the next two decades. In the San Joaquin Valley, this will likely mean taking more than 500,000 acres of agricultural land out of intensive irrigated production. Local and regional economies could be stressed as a result, with some regular employment opportunities in agriculture disappearing and public revenues declining if lands are not put to new uses. As landowners and newly formed groundwater agencies tackle the groundwater deficits in their areas, utility-scale solar development—already an attractive option for landowners owning property with or without water rights—could offer an opportunity to keep lands that exit irrigated production economically productive. Moreover, development could provide multiple benefits by helping to supplement habitat and mitigate dust generation on transitioning lands. However, the expansion of solar hinges on whether state-level energy system planning processes—in conjunction with local land use planning—can address the transmission challenges that threaten the region’s promise as a solar power hub.

Sonoma Valley Groundwater Sustainability Plan

Sonoma Water | January 29th, 2022

Source area management practices as remediation tool to address groundwater nitrate pollution in drinking supply wells

Journal of Contaminant Hydrology (Elsevier) | July 19th, 2019

Nitrate in drinking water may cause serious health problems for consumers. Agricultural activities are known to be the main source of groundwater nitrate contaminating ru

Nitrate in drinking water may cause serious health problems for consumers. Agricultural activities are known to be the main source of groundwater nitrate contaminating rural domestic and urban public water supply wells in farming regions. Management practices have been proposed to reduce the amount of nitrate in groundwater, including improved nutrient management practices and “pump and fertilize” with nitrate-affected irrigation wells. Here, we evaluate the feasibility and long-term impacts of agricultural managed aquifer recharge (Ag-MAR) in the source area of public water supply wells. A numerical model of nitrate fate and transport was developed for the Modesto basin, part of California's Central Valley aquifer system. The basin is representative of semi-arid agricultural regions around the world with a diversity of crop types, overlying an unconsolidated sedimentary aquifer system. A local public supply well in an economically disadvantaged community surrounded by farmland was the focus of this study. Model scenarios implemented include business as usual, alternative low-impact crops, and Ag-MAR in the source area of the public supply well. Alternative nutrient management and recharge practices act as remediation tools in the area between farmland and the public supply well. Improved agricultural source area management practices are shown to be an effective tool to maintain or even enhance groundwater quality in the targeted supply well while remediating ambient groundwater.

Source, movement and age of groundwater in the upper part of the Mojave River Basin, California, USA

Proceedings of the 1994 International Symposium on Application of Tracers in Arid Zone Hydrology | August 22nd, 1996

Water samples from wells were collected and analysed for oxygen-18, deuterium, tritium, carbon-14, and carbon-13 to determine the source, movement and age of groundwate

Water samples from wells were collected and analysed for oxygen-18, deuterium, tritium, carbon-14, and carbon-13 to determine the source, movement and age of groundwater in the upper part of the Mojave River basin. Water in the alluvial aquifer has a median deuterium composition of — 66% and contains tritium, and was recently recharged by water from the Mojave River. Water in the regional aquifer near the Mojave River, near Summit Valley, and underlying several small washes has deuterium compositions heavier than — 60 %. Although some water in the regional aquifer near the Mojave River contains tritium, most of this water does not contain tritium. Carbon-14 data indicate that this water was recharged less than 2400 years ago. Water in the remainder of the regional aquifer has a median deuterium composition of — 84 %, which is as much as 20 % lighter than the volume-weighted deuterium composition of present-day precipitation. These data show that this water was recharged under climatic conditions different from average conditions today. Carbon-14 data indicate that some water in the regional aquifer was recharged more than 20,000 years ago.

Source, Movement, and Age of Ground Water in a Coastal California Aquifer

U.S. Geological Survey (USGS) | July 11th, 1996

Understanding the contribution of recharge from different sources is important to the management of ground-water supply in coastal aquifers in California especial

Understanding the contribution of recharge from different sources is important to the management of ground-water supply in coastal aquifers in California especially where water-supply or water-quality problems have developed as a result of ground-water pumping. In areas where water levels have changed greatly as a result of pumping and no longer reflect predevelopment conditions, an analysis of isotopic data can provide information about the source, movement, and age of ground water that is not readily obtained from a more traditional analysis of ground-water data This information can be used to develop management strategies that incorporate the availability of natural and artificial recharge to control water-level declines and water-quality degradation. In this study, the ratios of the stable isotopes of oxygen and hydrogen were used to determine the source and trace the movement of ground water in the Santa Clara-Calleguas basin, Ventura County, California Tritium and carbon-14 data were used to estimate the age (time since recharge) of ground water.