Keywords:basin characterization, history, modeling, water and energy, water supply
This study assessed the history of oil production and pressure changes in the southern portion of the San Joaquin Basin in California’s Central...
This study assessed the history of oil production and pressure changes in the southern portion of the San Joaquin Basin in California’s Central Valley as a reverse analog for understanding the pressure response to potential geologic carbon sequestration.
Sequestration involves injecting carbon dioxide into permeable strata such as those that trap oil. This results in pressure increases in the existing fluid in the subsurface that can provide a motive force for brines at those depths to migrate into groundwater, affecting its quality. The pressure can also cause differential ground surface uplift that can affect surface water flow, particularly in engineered water conveyances such as canals.
The strata underlying the Central Valley have been assessed as having considerable capacity to store carbon dioxide, but the area also contains urban areas and extensive agriculture that rely on engineered surface water delivery systems and groundwater supplies. The Stevens Sand, Temblor Formation and Vedder Formation were identified as having the largest cumulative net production from typical geologic carbon sequestration depths.
Two oil pools were identified in each of these stratigraphic units for more detailed analysis, which included converting fluid level data to pressure at the pool scale. Data were collected that allowed an assessment of the hydraulic connectivity of each unit. The results indicated that the Vedder was hydraulically connected at the near basin scale, the Stevens was hydraulically connected at the pool scale and was disconnected between pools and the Temblor was disconnected within pools. Researchers used these results to analyze possible brine leakage driven by geologic carbon sequestration. They also reviewed over 200 articles on historic groundwater contamination. They concluded that no instance of contamination due to upward leakage of brine in the Central Valley was reported.
This report presents results from an analysis of the institutional and legal options for more effective ecosystem management in the Sacramento-San Joaquin Delta....
This report presents results from an analysis of the institutional and legal options for more effective ecosystem management in the Sacramento-San Joaquin Delta. It is part of a wide-ranging study on the management of multiple ecosystem stressors in the Delta. .
The report focuses on the State Water Board’s responsibility to enforce water rights and to prevent unauthorized diversions of water in the state...
The report focuses on the State Water Board’s responsibility to enforce water rights and to prevent unauthorized diversions of water in the state of California.
Pursuant to the Water Code, the State Water Board is responsible for enforcing the terms and conditions of water right permits, licenses, and registrations, as well as investigating diversions of water. As addressed in the Strategic Workplan for Activities in the San Francisco Bay / Sacramento-San Joaquin Delta Estuary, the State Water Board is directed to investigate illegal diversions and violations of permit and license conditions and take action when violations are occurring in the Bay-Delta Watershed.
The report discusses how the State Water Board began an investigation of illegal diversions of water, focusing on the Delta. For instance, the State Water Board has investigated two islands in the Delta to establish whether the landowners possessed any water rights. Most did, though some individuals were subject to more review, the majority of which concerned validating riparian claims for severed parcels.
The report notes that the State Water Board has also investigated diverters within an area of the southern Delta and resolved all cases resulting from that investigation. The report also discusses how the State Water Board has begun an investigation of water diverters, statewide, who have failed to file required reports, which include the annual reports for permit and license holders, and the supplemental statements.
Finally, the report suggests a new approach of looking at districts in the Delta who serve water to individuals, in addition to looking at compliance issues related to individual diverters.
Historically, groundwater has been pumped as needed in many areas of the state, often with little regard for the deleterious effects of over...
Historically, groundwater has been pumped as needed in many areas of the state, often with little regard for the deleterious effects of over pumping. Over pumping is not sustainable in the long-term and can lead to a number of adverse consequences, including water-quality degradation; increased energy costs for groundwater pumping; costs for well deepening or replacement; impacts to nearby rivers and streams; and land subsidence.
This report highlights the current and historical impacts of land subsidence in California due to groundwater pumping and makes recommendations for monitoring and assessment. The purpose of this report is to summarize knowledge about the extent and costs of subsidence so that this information can be part of a larger discussion on sustainable groundwater management in California.
This report confirms that land subsidence in California is not just an historical occurrence, but that it is an ongoing problem in many regions. The report presents key examples of significant historical subsidence and current active occurrences of subsidence, including the impacts and costs.
There is no comprehensive land subsidence monitoring program in California. The information in this report was compiled from individual regional or local studies, which usually were initiated after substantial subsidence impacts had occurred. The most comprehensive evaluation of land subsidence in California occurred between 1955 and 1970, to assist with the construction of the state and federal water projects. Funding for this program ended soon after completion of the state and federal water projects. The lack of comprehensive subsidence monitoring has had costly consequences for the state.