Baker City Public Works Department crews had to contend with snow last week while building a retaining wall below Goodrich Lake, a drinking water source in the Elkhorn Mountains.
The project was prompted by a slide in early July caused by water seepage from springs. Two engineers from the U.S. Army Corps of Engineers examined the dam on July 5 and found no structural problems.
Engineers recommended the city clear debris from the outlet pipe below the dam.
Last week workers installed a new outlet pipe that’s protected by steel plates, said Michelle Owen, the city’s public works director.
Crews also built a retaining wall consisting of concrete blocks with layers of textile mesh between them.
Workers also connected the existing drain lines, which are intended to prevent water seepage from destabilizing the slope, and linked those lines to a pipe near one end of the wall.
This winter the city will work with engineers to design an improved drainage system for the site. Owen said that system is slated to be installed in 2020.
According to a report written by Dwayne M. Weston, chief of the engineering and construction division, and dam safety officer for the Corps of Engineers’ Walla Walla, Washington, District, the July slide of dirt and rocks covered an area about 150 feet by 75 feet.
“There were multiple active seeps from the slope failure area that appeared to be running clear water, and picking up sediment as it flowed down the face of the slope failure,” the report reads.
The city usually starts using water from Goodrich around late July or early August, when water demand rises and the flow of springs and streams in the city’s 10,000-acre watershed, on the east slopes of the Elkhorns, drops.