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Dam/reservoirs ranging from 6,000 af to 154,000 af have been studied. Project types include mainstem, tributary, and offstream (pumped storage) reservoirs. Facilities include dam, spillway, intake and outlet works and other structures, fish passage facilities, and access roads. Operations affected by fishery needs, whether requirements for direct releases or constraints on diversions for offstream projects.
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Larger mainstem projects (e.g., 24,000- af CRDRP) provide lawful supply and protection of public trust resources in compliance with Order WR 95-10. Smaller projects are questionable. Detailed evaluation based on operations criteria set by SWRCB is needed to confirm performance of specific projects. |
Capital costs for 6,000- to 24,000-af projects range from $87 million to $115 million. For 15,000- to 25,000-af Cañada Reservoir site options, costs range from $220 million to $270 million. O&M costs for nonpumped storage projects are about $3.5 million per year. O&M costs for pumped storage options range from $3.9 million to $8.5 million per year. These costs include mitigation, engineering design and contingencies. |
Up to 10 years needed for environmental review and to obtain permits. 1-2 years for final design. 2-4 years for construction, depending on project size and site. Long project life of dam structure (over 100 years); project designs include 100-year reserve for sedimentation. |
Major Benefits: Larger projects that provide instream flow help restore river environment and protect public trust resources (streamflow benefits fish and riparian corridor). Recreational and aesthetic benefits due to year-round flow. Relatively low energy use for gravity projects. Major Adverse Effects: Inundation by reservoir results in loss of fish/wildlife habitat and cultural resources sites. Depending on size and location, project could impact sediment transport and channel characteristics (and possibly benthic food species). Significant construction impacts for dam sites in Carmel Valley. Long-term visual changes. |
24,000-af NLP project has received state and federal permits and is considered feasible. Feasibility of tributary and offstream projects is questionable as instream flow may not compensate for habitat loss. Advantages include gravity capture and conveyance of rainwater (lower O&M), long project life, minor effect on Cal-Am system, steelhead passage and life cycle, streamflow and aquifer storage improvement. Disadvantages include high capital cost for massive structure, large land area, many mitigations for impacts, long design/construction period, and impaired performance in extended droughts. |
* "Feasible" means project is a reasonably foreseeable means to provide lawful supply for Cal-Am water system. See text for further discussion.