Dams: sedimentation studies.

Existing law requires the Department of Water Resources to make or cause to be made investigations and gather or cause to be gathered data as needed for a proper review and study of the various features of the design and construction of dams, reservoirs, and appurtenances. This bill would require the department, in collaboration with specified entities, to make or cause to be made investigations and to gather or cause to be gathered data for a proper review and study of the loss of storage capacity behind dams resulting from sedimentation and would authorize the department to limit the study to certain reservoirs. The bill would require results of the study to be reflected in the quinquennial update of The California Water Plan and be provided to the appropriate policy committees of the Senate and the Assembly. The bill would require the department to identify high-priority reservoirs for additional evaluation, for which the department would be required to evaluate and characterize the sediment for mercury and sediment size and to identify and evaluate cost-effective strategies for sediment removal, relative to the costs of alternative methods of flood protection and water supply. Existing law requires the Department of Water Resources to update The California Water Plan, which is a plan for the conservation, development, and use of the water resources of the state, every 5 years. Existing law requires the department, as part of the update, to conduct a study to determine the amount of water needed to meet the state's future needs. The department is required, one year prior to issuing each update to the California Water Plan, to release a draft of assumptions and estimates upon which the study will be based. Existing law prescribes a list of subjects for which the department is required to release those assumptions and estimates. This bill would add estimated loss of storage capacity behind dams resulting from sedimentation to that list.