Keywords:coastal aquifers, conjunctive use, drought, Groundwater Exchange, groundwater recharge, monitoring, planning and management, water supply
Section 229 of the Water Code directs that the California Department of Public Works, acting by and through the State Engineer, shall "investigate...
Section 229 of the Water Code directs that the California Department of Public Works, acting by and through the State Engineer, shall "investigate conditions of the quality of all the waters within the State, including saline waters, coastal and inland, as related to all sources of pollution of whatever nature and shall report thereon to the Legislature and to the appropriate regional water pollution control board annually, and may recommend any steps which might be taken to improve or protect the quality of such waters."
In order to carry out the intent of Section 228 of the Water Code with respect to investigations of quality of ground waters within the State, it has been necessary first to compile available geologic data in order to locale and define the approximate boundaries of the more important ground water basins.
A base index map showing the principal areas of groundwater storage in the State of California has not been previously prepared. Such a map has been complied for this report in order to establish a uniform name and numbering system for groundwater basins, which can be expanded as new areas of ground water storage are identified, or as it is found necessary to divide the larger areas into subbasins. It will serve as a basis for the planning of future investigations of the groundwater resources of California.
This report identifies alluvial or valley fill areas which contain the principal groundwater resources in California. However, the report is necessarily not complete because of lack of information for many areas of the state.
In general, the areas of groundwater storage indentified include: (a) the major alluvium-filled areas of known groundwater storage and extraction; (b) the extensive areas of alluvial-fill in the Colorado, Mojave, and Basin and Range desert areas which may contain usable groundwater, though little is known of their storage capacity or recharge; and (c) some of the smaller alluvium-filled areas which may furnish a portion of local domestic, irrigation, municipal, and industrial water supplies.
The establishment and management of a National Ground-Water Monitoring Network (NGWMN) in the United States would represent a significant achievement in water-resource management....
The establishment and management of a National Ground-Water Monitoring Network (NGWMN) in the United States would represent a significant achievement in water-resource management. The need for ground-water monitoring focused on the major aquifers and aquifer systems in the USA is increasingly important as a key element of sustainable ground-water resource management and use.
The National Framework described in this report provides detailed information and recommendations for developing and operating a national ground-water monitoring network that would provide ongoing data collection on ground-water quantity and quality. These data will be available to the public and will be critical for addressing ground-water management issues at the Federal, State, Tribal and local levels. The data will be particularly useful for “state of the resource” assessments requested by State Legislatures and the U.S. Congress. The National Framework was developed by the Subcommittee on Ground Water (SOGW), an ad-hoc committee under the Advisory Committee on Water Information (ACWI), which is a Department of the Interior Federal Advisory Committee.
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.
The primary goal of the Central Coast Hydrologic Region (Central Coast region) groundwater update is to expand information about region-specific groundwater conditions for...
The primary goal of the Central Coast Hydrologic Region (Central Coast region) groundwater update is to expand information about region-specific groundwater conditions for California Water Plan Update 2013, and to guide more informed groundwater management actions and policies.
A second goal is to steadily improve the quality of groundwater information in future California Water Plan (CWP) updates to a level that will enable regional water management groups (RWMGs) to accurately evaluate their groundwater resources and implement management strategies that can meet local and regional water resource objectives within the context of broader statewide objectives.
The final goal is to identify data gaps and groundwater management challenges meant to serve as a guidepost for prioritizing future data collection and funding opportunities relevant to the region.
This regional groundwater update is not intended to provide a comprehensive and detailed examination of local groundwater conditions, or be a substitute for local studies and analysis. Consequently, where information is readily available, the update does report some aspects of the regional groundwater conditions in greater detail.