Grant PUD completing refilling of Wanapum Dam reservoir
Repairs to the Wanapum complex in Washington reached a significant milestone in March, as owner Grant County Public Utility District began the process of refilling the reservoir behind Wanapum Dam to its full capacity. Grant PUD dropped water levels behind Wanapum Dam by about 30 feet in March 2014, following the discovery of a 65-foot-long by 2-inch-wide horizontal crack in the dam’s pier monolith No. 4 in February.
Grant PUD already raised the reservoir’s levels by about 17 feet in January amidst ongoing repair work to the dam, but the latest round of influx will restore the reservoir to its pre-rehabilitation levels.
The refill was scheduled to be complete in April.
“This is the last major milestone for this project and the reservoir is anticipated to be fully restored and functional to pre-existing conditions for public access and utilization,” said Grant PUD in a release.
The refilling marks the culmination of a year that included a number of initiatives related both directly and indirectly to the dam repair project, including the deployment of an innovative (and effective) fish-passage solution that has helped pass a record-breaking 800,000-plus fish above Wanapum Dam, implementation of a new shoreline security strategy, preservation of archaeological resources, and improvements to a number of recreational sites.
The dam is home to a 1,038-MW Wanapum hydro facility. Grant PUD said it has continued to generate power, albeit at reduced rates, despite the drawdown.
Corps releases safety report on Buckeye Lake Dam
The U.S. Army Corps of Engineers has identified “serious problems” and a “significant risk to the public,” according to its report detailing a year-long study of Buckeye Lake Dam in Ohio.
The dam is a 4.1-mile-long, earthen embankment structure completed in 1832 that is located in portions of Licking and Fairfield counties. The structure impounds more than 4.5 billion gallons of water at its principal spillway level. About 3,000 people and 2,100 homes exist in the projected failure inundation zone, which stretches more than 2 miles downstream.
The Corps’ study indicates Buckeye Lake Dam’s integrity has been significantly compromised — most likely as a result of man-made defects. According to the Corps, more than 370 homes and other structures have been sunk into the dam’s embankment, while other portions have been dug away to accommodate pools, patios, utilities and drainage structures.
The final report contains recommendations “for immediate and longer-term steps that should be taken to prevent the unacceptable consequences of a catastrophic failure.”
All of the manmade activity has weakened the dam and undermined its stability, increasing the likelihood that it will no longer be strong enough to hold back the weight of the water behind it, according to the Ohio Department of Natural Resources. The impacts to the dam have been observable, ODNR said, with “significant” seepage, subsidence, persistent wet areas and structural deterioration becoming larger concerns.
The Corps recommended several immediate steps to reduce the risk of dam failure, including: Maintaining a lower “winter pool” water level to reduce stress on the dam and provide more storage space in times of excessive rainfall; prohibiting additional structures from being built on the dam to prevent further erosion; and increasing disaster preparedness measures, including the stockpiling of sandbags and fill material, as well as emergency response planning and exercises.
ODNR said, “The safest solution for eliminating the risk of flooding” is to “drain the lake permanently,” although the agency is also considering replacing the dam with a new structure that meets current safety standards.
Dam Safety Awareness Week in Wisconsin includes precautions
During Wisconsin’s official Dam Safety Awareness week, April 5 through 11, the state’s Department of Natural Resources (DNR) encouraged residents to remain safe while at or near the more than 3,800 dams in the Great Lakes state.
The federal government provides oversight for about 200 large dams in Wisconsin that produce hydroelectricity. The Wisconsin DNR regulates the remaining dams, the majority of which were built prior to 1950.
Safety precautions include:
— Obeying all signs and barriers;
— Any sirens and flashing lights indicate an imminent change in water level or flow;
— Use a cell phone to call 911 in case of an emergency;
— Wear a life jacket;
— Always stay outside buoy lines and away from restricted areas; and
— Have a safe escape route planned when near a dam.
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