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Question 5: If the above modifications were made to Lower Granite Dam, what is BPA's 

 latest estimate of the annual costs of a ten week drawdown of Lower Granite 

 Dam to spillway cresf Please provide a breakdown for the various 

 components such as firm power, secondary power, etc. 



Answer. The losses we estimate would occur from operating Lower Granite to 



spillway crest for a 10-week period would be similar to those operating at 

 elevation 710 feet (about a 30 foot draw down). A similar scenario was 

 analyzed in the 1992 Columbia River Salmon Flow Measures Options 

 Analysis Environmental Impact Statement(OA/EIS). The OA/EIS analyzed a 

 12-week draw down period from April 1 through June 30 with 2 weeks 

 required at the outset to bring the reservoir to the draw down elevation, 

 8 weeks at the draw down elevation, and 2 weeks required at the end of the 

 period to refill reservoir levels back to their previous elevation. These losses 

 amounted to $18 million per year of lost firm energy and $1 1 million of lost 

 firm capacity. Non-firm losses are estimated to be in the range of 

 $1 1 - $20 million Therefore total annual operational losses for this 12-week 

 draw down at Lower Granite is in the range of $40 - $49 million. BPA 

 assumes that the 1 0-week draw down would have similar cost impacts 

 assuming it too has a ramp-up and ramp-down period. 



The annual capital cost for Lower Granite is estimated to be about 

 $5 - $7 million This is based on a low range estimate of $60 million in total 

 capital costs and a high range estimate of $86 million amortized over 50 years 

 (current practice for Corps of Engineers plan investments) financed at a 7.25 

 percent Treasury borrowing rate. 



Combining the annual capital costs of about $5 to $7 million at Lower Granite, 

 (derived from the modification costs identified in the previous answer) with the 



