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20-011 Corps continues assisting flood recovery efforts

Published March 6, 2020

Walla Walla Wash. -  The Walla Walla River basin's rain-on-snow event resulted in historic flows on most streams and rivers in the region. In the aftermath of the flood event, officials with the U.S. Army Corps of Engineers Walla Walla District shifted their focus from flood fighting to helping restore some of the surrounding flood effected areas.

“These were the highest peak inflows ever recorded at Mill Creek Project,” Walla District’s Emergency Readiness Chief Linda Campbell said. According to Campbell without the Mill Creek Flood Control Project, there would have been 45,000 gallons of water per second flowing uncontrolled through the city of Walla Walla. 

Though the Mill Creek Project worked as designed, and kept the city of Walla Walla dry, flood waters hit the surrounding communities. The Walla Walla District sent nine teams to Waitsburg, Starbuck, Camp Wooten, Kamiah, Mill Creek, Dayton, Milton-Freewater, the city of Walla Walla water line, and Walla Walla’s Bridges, to provide technical assistance in flood response operations, damage assessments and flood fight techniques.

During the Mill Creek flood fight Corps staff managed flood water by operating flood gates and diversion channels to redirect excess water to Bennington Lake, ensuring that water flowing down the Mill Creek Channel stayed off the streets of Walla Walla.

The Milton-Freewater levees experienced erosion damage in numerous locations on both sides of the Walla Walla River. Breaches occurred in the levees on both banks downstream of the Couse Creek Road bridge, upstream of Milton-Freewater. 

The Corps used a contractor for emergency measures at the breach sites. These measures consisted of the emergency repair of nearly 1,100 cumulative feet of breaches on both banks of the river “Contractors replaced over 1100 feet of levee that was washed out by the flooding,” Matthew Reeves, the Resident Engineer in the Upper Snake Construction office for the Walla Walla District USACE said. “Its completion provides a 100 year level of protection reducing any further damage from future flooding events.”

 “We provided emergency repairs based on the damages that occurred earlier this month, and the breaches that occurred on the levee, Campbell said.”  “If there were another high-water event before the permanent repairs were completed, those emergency repairs would provide something close to the same level of protection that they have had prior to the flood event,” she said.

Emergency repairs were completed Thursday March 5th. Meanwhile, the Walla Walla District is prepared to receive rehabilitation assistance requests from several sponsors of levee systems in the region that are active in the District’s Rehabilitation Program.

“Once received, we will perform damage assessments and then prepare project information reports to address the damage. It is anticipated that levee rehabs will be needed in numerous locations.” said Emergency Management Specialist Robert Herres.

Corps officials also supplemented state and local efforts and provided 20,000 sandbags to Columbia County, 20,000 to Umatilla County, 10,000 to the City of Waitsburg and 5,000 to Walla Walla County.