Utility district says Wanapum Dam stable

Utility district says Wanapum Dam stable
Wanapum Dam (Wikimedia Commons photo by Williamborg)

"EAP Status Report for Wanapum Dam at 1:00 pm March 1, 2014

Alignment surveys taken over the past few days do not show additional movement of the damaged spillway section at Wanapum Dam. By 1:00 pm today, the Wanapum Dam forebay has been drawn down to elevation 559.3’.

The damaged area has not resulted in an uncontrolled discharge and we continue to monitor and evaluate the situation. The District continues to lower the water levels above Wanapum Dam (forebay) in a steady, controlled manner. We anticipate drawing down the reservoir to approximately 550 – 552’ m.s..l at the minimum rate of 3 feet per day to stabilize the situation. River flows are currently 90,000 cfs and are not expected to materially increase as the draw down continues through Monday, March 3, 2014.

In a worst case scenario, if one of the spillway sections failed, the remainder of the spillways and the main dam structure would remain intact. Under current river conditions, the amount of water that would flow through this spillway section would be within the range of normal river conditions.

Grant PUD engineers continue to work with consultants and the Federal Energy Regulatory Commission to evaluate the extent of the structural damage and appropriate corrective measures. Operators, Engineers and Engineering Technicians will continue to inspect, survey and monitor the alignment of the spillway on a daily basis. These efforts will continue through the weekend.

Increased security patrols will be in effect until further notice. The boat launches at Wanapum and Priest Rapids pools remain closed. No facility evacuations are anticipated at this time.

We will keep you updated on the situation at the dam and river flows as more information becomes available."