Keywords:Central Valley Project (CVP), Sacramento–San Joaquin Delta, water supply
The Delta Plan should identify the authorities of the State Water Board that may be employed to implement its goals, subgoals, and strategies....
The Delta Plan should identify the authorities of the State Water Board that may be employed to implement its goals, subgoals, and strategies. The State Water Board’s Bay Delta Plan and Delta Strategic Workplan should be incorporated into the Delta Plan.
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. .
Earthquakes and high water as hazards to Delta levees were reviewed in a seven-hour workshop organized by the Delta Independent Science Board and...
Earthquakes and high water as hazards to Delta levees were reviewed in a seven-hour workshop organized by the Delta Independent Science Board and held at the campus of the University of California, Davis.
Earthquake hazards in the Delta were described in terms of ground motions from Bay Area earthquakes, infrequent earthquake recurrence on faults beneath the Delta, and levee fills prone to earthquake-induced liquefaction. Large uncertainties attend all these seismic elements of levee hazard. Those uncertainties, according to presentations in the workshop, include whether the Delta ground motions previously computed for Bay Area earthquakes were too large. Hazards from high water were deemed greatest from the confluence of high river discharge, wind-driven surge and waves, and high tides. Major risk assessments have used available data on these hazards without mandates to advance the science.
Research needs and opportunities identified in the workshop include expanded observations of Delta ground motions, improved estimates of geologically recent displacement on faults beneath the Delta, further identification of liquefiable materials and mechanisms beneath levees, continued airborne measurements of land-level change, updated mapping of the contracting area of remaining peat, and fuller documentation of past levee failures. Recurring assessments of earthquake hazards and climate change provide precedents for periodic reappraisal of Delta levee risk.
The workshop brought together different parts of the diverse community of Delta levee specialists. Positive responses to the workshop suggest that it served levee specialists and outsiders alike.
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.