Crews begin installing anchor tendons at Wanapum Dam
EPHRATA, Wash.— Grant PUD and its contractors recently installed the first of 35 steel anchor tendons on the Wanapum Dam spillway, paving the way to increase the river elevation behind the dam later this year.
The tendons begin at the top of the spillway and end deep into the bedrock below the dam, ensuring the long-term stability of the spillway. Along with the approximately 200-foot-long anchor tendons throughout the spillway, work is also underway to install over 50 steel anchor bars to repair the one fractured spillway structure.
The work is expected to continue into the first quarter of 2015, with enough of the installations completed to partially raise the level of the reservoir behind the dam in the fourth quarter of 2014, pending the Federal Energy Regulatory Commission (FERC) approval. These repairs and the subsequent increase in river elevation, will allow the utility to restore public access to the shoreline, increase electric generation, improve public safety concerns and protect culturally-sensitive sites. Until the reservoir is raised, the shoreline and access points will remain closed to the public. The utility will provide an update with specific timeframes for raising the river elevation and restoring public access.
As estimates are refined and construction plans finalized, the operational and repair costs of the Wanapum Dam Spillway response are estimated at $69 million. Grant PUD’s strong financial position allows the utility to pay for its proportionate share of the cost by using cash reserves and selling bonds. The utility isn’t expecting any revenue increases for retail customers beyond the previously planned 2 percent increase included in the current forecast. Wanapum Dam continues to generate electricity and accommodate river flows in coordination with the other dam operators on the Columbia River. The plant continues to operate approximately 26 feet below the normal operating range.
Modifications to Wanapum Dam’s two fish ladders have proven successful during this year’s record-breaking adult migration season. Over 700,000 salmon and steelhead have already passed the dam on their journey to upstream spawning habitat.
During the drawdown, Grant PUD has accelerated plans for improvements to three boat launches on the reservoir. Improvements to the Vantage and Frenchman Coulee boat launches have recently been completed and work to remove sediment from the Crescent Bar Boat Launch channel has begun. Doing this work during the drawdown results in substantial cost savings, reduced environmental impact, provides better quality control, and reduces the construction period.
To view the repair work visit our YouTube channel at: http://youtu.be/x-XluPffTEc
For additional information on the Wanapum Dam issue, visit: http://www.grantpud.org/your-pud/media-room/wanapum-dam-spillway-response.
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