Corps starts work on Green Peter Dam

The U.S. Army Corps of Engineers started work on one of Green Peter Dam’s two spillway gates Monday.

The work is similar to that performed on the spillway gates at Foster Dam in 2008 and 2009, strengthening the gate face; replacing the gate’s arms, trunnion pins and wire ropes; and replacing or refurbishing electrical controls, gearboxes and other systems, said Scott Clemans, public affairs specialist.

The road over the dam and adjoining areas will have a lot of construction activity and equipment, Clemans said. A public closure of the entire area from Quartzville Road on the north bank to the private property gate on the south bank, including the North Viewpoint and Billings Park, will be in effect.

The road over the dam will have one 12-foot lane open from Sept. 15 to Sept. 30, and then from Dec. 1 until the project concludes in mid February.

The road will close entirely Oct. 1 to Nov. 30 except for emergencies. In case of an emergency, the contractor can provide a 12-foot access lane on the roadway deck for an emergency vehicle to pass within 20-30 minutes of notification – unless a critical lift is in progress, in which case the deck may be completely obstructed for several hours.

Emergency access across the dam should be requested by calling the Foster Dam Control Room operator at (541) 367-5124. The control room is staffed 24 hours per day, seven days per week.

“We understand the impact of this project on the local community and reservoir users, but our highest priority is ensuring Green Peter Dam’s ability to reduce flood damage in your downstream communities,” Clemans said.

“The 2011-12 flood season is a good illustration of why: The dam prevented the South Santiam River from rising eight additional feet at the Waterloo gauge during the January 2012 storm event, and is estimated to have prevented over $17 million in damage to downriver communities.”

This time frame was chosen because it is on the back shoulder of wildland fire season and the front shoulder of flood season, Clemans said. Construction crews will pin the spillway gate face in place to hold back water, which should allow the reservoir to rise up to elevation 985 feet above sea level (about 15 feet above the spillway crest) during significant rain events.

“As always, our goal is to keep the river below flood stage.”