Keywords:groundwater recharge, urban water conservation
San Francisco Bay enters most of our lives as an obstacle to pass over as quickly as traffic-choked bridges allow. Although this beats...
San Francisco Bay enters most of our lives as an obstacle to pass over as quickly as traffic-choked bridges allow. Although this beats earlier attitudes—when we saw the Bay mainly as a dumping ground, a dam site, or a pit to fill in and pave over—we remain largely oblivious to one of the most remarkable wild resources in urban North America. Beneath our wheels lies a world of interesting and outlandish life, with much that puzzles even the scientists who regularly plumb its depths.
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.
Facing a fourth consecutive year of drought in 2015 and consequential threat of curtailments, farmers in the Delta proposed a voluntary program to...
Facing a fourth consecutive year of drought in 2015 and consequential threat of curtailments, farmers in the Delta proposed a voluntary program to significantly reduce their surface water diversions during the critical summer growing season. This is a report describing the context, origin, objectives, regulatory framework, implementation and results of that program.
The Assembly Select Committee on Water Consumption and Alternative Sources was established in February 2015 to examine the strategies California could take to...
The Assembly Select Committee on Water Consumption and Alternative Sources was established in February 2015 to examine the strategies California could take to improve water conservation and expand the portfolio of water sources. Given that California rose to the challenge of conservation, the committee turned its attention to alternative water source strategies such as stormwater capture, ocean desalination and water recycling, holding specific hearings to discuss the latter two in greater detail.
This report is the culmination of several hearings held across the state on issues of water use and opportunities for expanding water sources. It includes summaries of expert testimony at those hearings, including illustrative slides from their presentations, as well as a list of key
findings and recommendations compiled by committee staff and approved by the Chair. These findings and recommendations were not voted on by members of the Select Committee and may not reflect the view of each Select Committee member. This report is meant to provide knowledge regarding California’s drought, climate change future, and viability of water sourcing strategies including stormwater capture, water recycling and desalination. This knowledge will be essential in adapting California’s water infrastructure to climate changes and devising the most effective and environmentally friendly approach to endure the next California drought.