Grant County PUD has began to refill the reservoir behind Wanapum Dam back to normal levels, just over a year after a fracture was discovered on the dam's spillway.
The refill began March 16, and depending on river flows, the utility expects to be at normal river levels within seven to 14 days. This is the last major milestone for this project and the reservoir is anticipated be fully restored and functional to pre-existing conditions for public access and utilization.
This final refill marks an end to the drawdown, which began back in late February of 2014 when the reservoir behind Wanapum Dam was lowered in response to the discovery of the fracture by divers brought in to inspect the dam. The repairs bring the spillway structure back into compression and allow continued safe generation of renewable hydroelectricity, the utility said in a statement.
A mathematical error during the pre-construction design of the dam was identified as a cause of the fracture. Work to repair the dam included the installation of 35 anchor tendons on the spillway.
