On March 4, 2014, AlertsUSA issued the following
Flash message to subscriber mobile devices:
AlertsUSA monitoring major crack discovery in Wanapum Dam on Columbia River ~ 20 mi upriver from Hanford nuclear site in WA state. Significant risk of failure.
On Tues of this week, AlertsUSA subscribers were notified via text messages to their mobile devices of a potentially dangerous situation unfolding at the Wanapum hydroelectric dam located on the Columbia River in Washington state. A 2 inch wide, 65 foot long crack has been discovered in the structure and deformation of the dam is clearly visible. A potential threat of national significance exists as the dam is located less than 21 miles upstream from the Hanford Nuclear Site and approximately 60 miles upstream from the Columbia Generating Station, the Pacific Northwest’s only commercial nuclear reactor.
As of the time of this reports preparation, federal and state engineers indicate, at least publicly, they have no idea what caused the failure. In order to relieve pressure on the dam workers released significant amounts of water in the reservoir, lowering it’s level by 26 feet. The result is that the deformation of the structure has lessened, but the failure still remains, as does the threat to downstream communities and the nuclear facilities mentioned above.
There are growing concerns about the stability of the dam once the Spring melt begins as the volume of water in the Columbia River will increase dramatically.
Specifically, the failure is a crack in the large concrete base of the spillway known as the “ogee” (see diagram below). When a spillway gate is opened, water on the reservoir side of the dam flows over the ogee to head downriver. Divers have confirmed the ogee is cracked all the way across its upstream face, underwater.
According to Chuck Berrie of the Grant County Public Utility District, what’s troubling to experts on dams and concrete structures is that the ogee is not only cracked, it’s slipped a little…
AlertsUSA continues to monitor the situation at the Wanapum Dam closely and will immediately notify service subscribers of any change in the threat environment as events warrant.