Reconnaissance-Level Water Action Plan

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As noted in comments received from Nebraska, a re- regulating reservoir within CNPPID's system is estimated to take five to seven years to implement. A final design study and several state and federal permits would be required prior to construction. 0 Expected Project Life: The project life of a re- regulating reservoir would most likely extend well beyond the first increment of the Program. If properly maintained and operated, reservoir lives can exceed 75 to 100 years. Existing seepage problems associated with some of these sites could impact the project life depending on whether seepage problems can be avoided or mitigated. 0 Capital And Operational Costs: The HDR report was relied. on for cost estimates with the exception of hydropower impacts. The capital and annual costs for this project include costs associated with land acquisition, access, pump intake system, outlet structure and system, spillway, construction of the earthen darn, annual operations and maintenance costs, and lost hydropower revenue. Most of the capital construction costs were determined by estimating the quantities of the components and multiplying by a unit cost for each. Some of the assumptions used by HDR for unit costs are as follows: • $5 per cubic yard for embankment material complete in place. • $35 per square yard for riprap with a sand filter. • $340 per acre for mulching on the face of the dam. • $8,000 per drop structure on spillway channels. • Intake and outlet system costs are variable based on site conditions. • $1000 per acre for land acquisition. • Pump system costs were based on the power required to operate pumps at given flowrates and heads. • Annual operations and maintenance costs were estimated to be 5 percent of pump capital costs. • Mean annual lost hydropower costs were estimated to be $3 per acre -foot per hydropower plant bypassed. (Per personal communication with Mike Drain of CNPPID, May 16, 2000, this figure is in error and should have been $4 per acre - foot, therefore, the $4 figure has been used in this Water Action Plan. Furthermore, this figure represents loss of hydropower revenue to CNPPID but does not reflect loss in revenue to NPPD.)1 $125,000 per mile for construction of access roadway. The total capital costs and annual operations and maintenance costs are summarized in the table below. Nebraska is reserving 31 to 50 percent of the estimated 8,000 ac -ft/yr yield (or 2,500 to 4,000 ac -ft/yr of reserved yield) to offset future depletions, in which t For some reservoirs there will be annual costs associated with lost hydropower generation because releases bypass a plant. Water diverted to storage will be taken out above the hydropower plant and released below the generator. \ \DN00 \E- DRIVE\PROJECTS\Platte \Work Products \Task 9 \wapc report (Version 7).doc 13-