Recommendations on Model Criteria for Groundwater Sampling, Testing, and Monitoring of Oil and Gas Development in California

California State Water Resources Control Board (SWRCB) | June 1st, 2015

In California Senate Bill 4 (Pavley, 2013; hereafter referred to as “SB4”), the California legislature found and declared that protecting the state’s groundwater f

In California Senate Bill 4 (Pavley, 2013; hereafter referred to as “SB4”), the California legislature found and declared that protecting the state’s groundwater for beneficial use, particularly sources and potential sources of drinking water, is of paramount concern. Access to safe drinking water is a major issue for California, especially to its disadvantaged communities. State policy is that every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption, cooking, and sanitary purposes (Chapter 524, Statutes of 2012 (Assembly Bill 685, Eng)). SB4 further found and declared that strategic, scientifically based groundwater monitoring of the state’s oil and gas fields is critical to allaying the public’s concerns regarding well stimulation treatments of oil and gas wells.

Recommendations to Address the Expansion of Seawater Intrusion in the Salinas Valley Groundwater Basin

Monterey County Water Resources Agency (MCWRA) | October 12th, 2017

This report provides a discussion of the current knowledge and related background information surrounding seawater intrusion pathways and potential impacts ther

This report provides a discussion of the current knowledge and related background information surrounding seawater intrusion pathways and potential impacts thereof on the Salinas Valley Groundwater Basin. This document also serves as a body of evidence to catalogue the findings used to support the recommendations presented herein. Staff is making six recommendations, with each focused on a component that influences, or could be impacted by, the advancement of seawater intrusion. The recommendations are being presented in an order that builds upon the foundational knowledge laid out in the background section of this report, rather than in an order of priority. Each recommendation can be implemented on its own or in concert with the others, and the relative importance of each will be discussed individually in this report. However, the recommendations have been conceptualized as a comprehensive solution that, along with continued operation of projects that have been constructed for the same purpose, have the strongest potential to ensure success in slowing or halting further seawater intrusion when implemented simultaneously.

Reduction of Nitrates in Groundwater – Agricultural Expert Panel Report

California State Water Resources Control Board (SWRCB) | September 9th, 2014

Recommendations to the State Water Resources Control Board pertaining to the Irrigated Lands Regulatory Program The Agricultural Expert Panel (Panel) was convened to a

Recommendations to the State Water Resources Control Board pertaining to the Irrigated Lands Regulatory Program The Agricultural Expert Panel (Panel) was convened to address thirteen questions posed by the State Water Resources Control Board (State Water Board). The questions were primarily technical in nature, and are abbreviated below. 1. How can risk to or vulnerability of groundwater best be determined in the context of a regulatory program such as the Irrigated Lands Regulatory Program (ILRP)? 2. Evaluate and develop recommendations for the current approaches taken to assessing risk to or vulnerability of groundwater. 3. How can risk to or vulnerability of surface water best be determined in the context of a regulatory program such as the ILRP? 4. Evaluate and develop recommendations for the current approaches taken to assessing risk to or vulnerability of surface water. 5. What management practices are expected to be implemented and under what circumstances for the control of nitrogen? 6. What management practices are recommended for consideration by growers when they are selecting practices to put in place for the control of nitrogen? 7. Evaluate and make recommendations regarding the usage of various nitrogen management and accounting practices. 8. Evaluate and make recommendations regarding the most effective methods for ensuring growers have the knowledge required for effectively implementing recommended management practices. 9. What measurements can be used to verify that the implementations of management practices for nitrogen are as effective as possible? 10. Evaluate and make recommendations regarding the usage of various verification measurements of nitrogen control. 11. Evaluate the relative merits, and make recommendations regarding the usage of, surface water measurement systems derived from either receiving water or a discharge monitoring approach to identify problem discharges. 12. Evaluate and make recommendations on how best to integrate the results of the Nitrogen Tracking and Reporting System Task Force with any above recommendation regarding management practices and verification measures. 13. Evaluate and make recommendations on the reporting requirements to report budgeting and recording of nitrogen application on a management block basis versus reporting aggregated numbers on a nitrate loading risk unit level.

Reference Guide to On-Farm Groundwater Recharge on Annual Cropland | Recommendations for Creating Waterbird Habitat Benefits

Nature Conservancy | May 1st, 2019

With the Sustainable Groundwater Management Act (SGMA) requiring basins to balance water budgets and manage groundwater sustainably, there is an opportunity to demonstr

With the Sustainable Groundwater Management Act (SGMA) requiring basins to balance water budgets and manage groundwater sustainably, there is an opportunity to demonstrate groundwater recharge with benefits to birds and people. A multiple-benefit approach brings together water managers, farmers, agencies and conservation groups to stabilize groundwater in a manner that provides greater water reliability for farms and communities while protecting ecosystems, including migratory bird habitat.

Regional Ground-Water Evapotranspiration and Ground-Water Budgets, Great Basin, Nevada

U.S. Geological Survey (USGS) | July 1st, 2000

Regional land subsidence accompanying groundwater extraction

Hydrogeology Journal (Springer) | August 26th, 2011

The extraction of groundwater can generate land subsidence by causing the compaction of susceptible aquifer systems, typically unconsolidated alluvial or basin-fill aquif

The extraction of groundwater can generate land subsidence by causing the compaction of susceptible aquifer systems, typically unconsolidated alluvial or basin-fill aquifer systems comprising aquifers and aquitards. Various ground-based and remotely sensed methods are used to measure and map subsidence. Many areas of subsidence caused by groundwater pumping have been identified and monitored, and corrective measures to slow or halt subsidence have been devised. Two principal means are used to mitigate subsidence caused by groundwater withdrawal—reduction of groundwater withdrawal, and artificial recharge. Analysis and simulation of aquifer-system compaction follow from the basic relations between head, stress, compressibility, and groundwater flow and are addressed primarily using two approaches—one based on conventional groundwater flow theory and one based on linear poroelasticity theory. Research and development to improve the assessment and analysis of aquifer-system compaction, the accompanying subsidence and potential ground ruptures are needed in the topic areas of the hydromechanical behavior of aquitards, the role of horizontal deformation, the application of differential synthetic aperture radar interferometry, and the regional-scale simulation of coupled groundwater flow and aquifer-system deformation to support resource management and hazard mitigation measures.

Regional nitrate and pesticide trends in ground water in the eastern San Joaquin Valley, California

American Society of Agronomy (ASA) | September 18th, 2008

Protection of ground water for present and future use requires monitoring and understanding of the mechanisms controlling long-term quality of ground water. In this stu

Protection of ground water for present and future use requires monitoring and understanding of the mechanisms controlling long-term quality of ground water. In this study, spatial and temporal trends in concentrations of nitrate and pesticides in ground water in the eastern San Joaquin Valley, California, were evaluated to determine the long-term effects of agricultural and urban development on regional ground-water quality. Trends in concentrations of nitrate, the nematocide 1,2-dibromo-3-chloropropane, and the herbicide simazine during the last two decades are generally consistent with known nitrogen fertilizer and pesticide use and with the position of the well networks in the regional ground-water fl ow system. Concentrations of nitrate and pesticides are higher in the shallow part of the aquifer system where domestic wells are typically screened, whereas concentrations are lower in the deep part of the aquifer system where public-supply wells are typically screened. Attenuation processes do not seem to significantly affect concentrations. Historical data indicate that concentrations of nitrate have increased since the 1950s in the shallow and deep parts of the aquifer system. Concentrations of nitrate and detection of pesticides in the deep part of the aquifer system will likely increase as the proportion of highly affected water contributed to these wells increases with time. Because of the time of travel between the water table and the deep part of the aquifer system, current concentrations in public-supply wells likely reflect the effects of 40- to 50-year-old management practices.

Regional patterns in the geochemistry of oil-field water, southern San Joaquin Valley, California, USA

Applied Geochemistry (Elsevier) | September 21st, 2018

Chemical and isotopic data for water co-extracted with hydrocarbons in oil and gasfields are commonly used toexamine the source of the formation water and possible impact

Chemical and isotopic data for water co-extracted with hydrocarbons in oil and gasfields are commonly used toexamine the source of the formation water and possible impacts on groundwater in areas of oil and gas de-velopment. Understanding the geochemical variability of oil-field water could help to evaluate its origin anddelineate possible contamination of shallow aquifers in cases where oil-field water is released to the environ-ment. Here we report geochemical and multiple isotope (H, C, O, Sr, Ra) data from 22 oil wells, three sources ofproduced water that are disposed of in injection wells, and two surface disposal ponds in four oilfields in thesouthern San Joaquin Valley, California (Fruitvale, Lost Hills, North and South Belridge). Correlations betweenCl andδ18O, as well as other ions, and gradual increases in salinity with depth, indicate dilution of one or moresaline end-members by meteoric water. The saline end-members, represented by deep samples (610 m–2621 m)in three oil-bearing zones, are characterized by NaeCl composition, near-seawater Cl concentrations (median20,000 mg/L), enrichedδ18OeH2O (median 3.4‰), high ammonium (up to 460 mg-N/L), and relatively highradium activity (226Ra+228Ra = 12.3 Bq/L). The deepest sample has low Na/Cl (0.74), high Ca/Mg (5.0), andlow87Sr/86Sr (0.7063), whereas the shallower samples have higher Na/Cl (0.86–1.2), Ca/Mg near 1, and higher87Sr/86Sr (∼0.7083). The data are consistent with an original seawater source being modified by various depthand lithology dependent diagenetic processes. Dilution by meteoric water occurs naturally on the east side of thevalley, and in association with water-injection activities on the west side. Meteoric-waterflushing, particularlyon the east side, results in lower solute concentrations (minimum total dissolved solids 2730 mg/L) and totalradium (minimum 0.27 Bq/L) in oil-field water, and promotes biodegradation of dissolved organic carbon andhydrocarbon gases like propane. Acetate concentrations andδ13C of dissolved inorganic carbon indicate biogenicmethane production occurs in some shallow oil zones. Natural and human processes produce substantialvariability in the geochemistry of oil-field water that should be considered when evaluating mixing between oil-field waters and groundwater. The variability could result in uncertainty as to detecting the potential source andimpact of oil-field water on groundwater.

Regional water table (1994) and water-level changes in the Morongo Basin, San Bernardino County, California

U.S. Geological Survey (USGS) | July 1st, 1995

The Morongo Basin is in the Mojave Desert region of southern California, about 100 mi east of Los Angeles. Ground water is virtually the sole source of water in the Moro

The Morongo Basin is in the Mojave Desert region of southern California, about 100 mi east of Los Angeles. Ground water is virtually the sole source of water in the Morongo Basin. Increased pumping to meet the needs of an increasing resident population has resulted in ground-water overdraft in parts of the ground-water basin. Most of the water resources of the basin are managed by the Mojave Water Agency (MWA) and the U.S. Marine Corps Air/Ground Combat Center at Twentynine Palms (USMCAGCC). To help manage the ground-water resources, the MWA and the U.S. Marine Corps, Department of the Navy, requested the U.S. Geological Survey (USGS) to construct a regional water-table map of the Morongo ground-water basin. The purposes of this study were to construct a regional water-table map and determine areas of water-level change in the Morongo Basin. Existing data were evaluated and water levels were measured in selected wells throughout the Morongo Basin. Water-level measurements were used to construct a regional water-table map for 1994 conditions (fig. 1), and available historical water levels were used to construct hydrographs (shown in fig. 1) and determine water-level change at selected wells. Results of this study will aid the USGS in evaluating its current ground-water monitoring network in the Morongo Basin. In addition, information gained through this study will contribute to ongoing projects in the area, such as the Regional Aquifer-System Analysis (RASA) of Southern California.

Regional water table (1996) and water-level changes in the Mojave River, Morongo, and Fort Irwin ground-water basins, San Bernardino County

U.S. Geological Survey (USGS) | July 1st, 1997