Released On: December 19, 2011
The FONSI is based on the Environmental Assessment (EA) finalized by the Bonneville Power Administration (BPA) which proposes to replace six underground lines with overhead lines that will run from the TPP to a 500-kV spreader yard located about one mile west of the dam. BPA is expected to issue its own FONSI document on this project soon.
The six existing underground lines are an assembly of 18 aging, oil-filled lines. The new overhead transmission lines will stretch from the powerplant, across the Columbia River, over the visitor center area, and then proceed uphill to existing lines that transfer power into BPA's regional grid network.
The condition of the existing high voltage cables are degraded which increases risk of failure during operation. The new overhead transmission lines can be inspected and maintained more safely and economically.
Six new towers ranging in height from 280 feet to 316 feet will be constructed to hold the transmission lines which will be strung by helicopter and ground crew coordination.
Construction work is scheduled to begin in March 2012 and be completed by the end of the year. An informal open house meeting will be held close to the time when construction begins. At the meeting, there will be opportunities to learn more about the project, the proposed construction schedule and discuss the project with the construction contractors, Reclamation and BPA staff. Additional information about the open house will be sent out a few weeks prior to the meeting.
It is necessary to complete the transmission line project prior to the beginning of the TPP overhaul which is expected to start in Fiscal Year 2013.
Grand Coulee Dam, completed in 1941, it is a multi-purpose facility and a key feature of Reclamation's Columbia Basin Project. Power facilities at Grand Coulee Dam include 33 generators in three power plants, a pumping plant and three switchyards. The Project's rated electrical capacity is 6,809,000 kilowatts; making it the largest hydroelectric dam in the U.S., which also provides water to about 600,000 acres in the Columbia Basin Project.
DOI | Recreation.gov | USA.gov
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