SEATTLE (Reuters) - A 65-foot-long (20-metre-long) crack has appeared along the base of a dam in Washington state, posing no public danger but prompting utility managers to lower water levels to assess needed repairs, a utility and local media said.
The 2-inch-wide (5-cm-wide) crack appeared in the spillway of the 8,320-feet-long (2535-metre-long) Wanapum Dam, a large hydroelectric power plant on the Columbia River that currently can generate more than 1,000 megawatts of power, the utility said late Friday.
The spillway is a channel that allows surplus water to escape and is used for the controlled release of flows from a dam.
"As a precautionary measure, the water above Wanapum Dam (forebay) is being drawn down to reduce the pressure on the spillway while inspectors investigate," Grant County Public Utility District spokesman Thomas Stredwick said.
The dam, about 18 miles upstream from Priest Rapids Dam in a rural part of central Washington, was still generating electricity, Stredwick said. But lower water flows during repairs could force the utility to buy power on the open market and affect the broader Columbia River hydroelectric system.
"All these dams coordinate to generate energy on a regional scope," Stredwick was quoted as saying in the Seattle Times. "If Wanapum is impacted, that has impacts on dams upstream as well as below."
Officials had already dropped the water level by 6 feet and planned to reduce it another 14 feet by Monday, the newspaper reported.
(Reporting by Eric M. Johnson in Seattle; Editing by Barbara Goldberg and Frances Kerry)