Pierce County cleans up landslide on South Prairie Road East

Approximately 700 to 800 tons of material were removed from the landslide on South Prairie Road East on March 16, but only 100 to 200 tons of debris came down in the landslide. Photo submitted by Pierce County Public Works Department

Last week, Pierce County cleaned up a mudslide that closed a part of South Prairie Road East outside of Bonney Lake.

According to Bruce Wagner and Paul Marsh of Pierce County’s Public Works Department, the slide was reported at 9 a.m, and the county closed South Prairie Road East from 234th Avenue East to state Route 162 from mid-morning to around 7:30 p.m on March 16.

Marsh, the department’s operations superintendent, said the landslide was “modest,” as around 100 to 200 yards of loose debris slid into a retaining wall along the road, with some spilling out.

It is estimated that 100 to 200 tons came down in the landslide, but a total of around 700 to 800 tons of debris was removed from the site.

Engineers were dispatched first to determine whether the area was secure and stable enough for crews to start removing debris. It was around noon when the removal crew was able to begin working.

Marsh said crews removed debris that has been collecting behind the retaining wall before the slide, so there is now more room to catch more material if another slide were to occur.

Beyond inconveniencing drivers getting in and out of the area, there was one parcel of land and a home below the slide, “but the house was located well away from where this material would have ended up at the bottom of the hill,” Marsh said.

In general, the county department doesn’t actively monitor potential landslide sites, but this particular area has a history, which is why a retaining wall was installed.

“We react when material comes down and threatens the roadway,” Marsh said. “We don’t actively monitor or specifically monitor necessarily, unless we’re aware of something – we’ll keep an eye on it now, of course.”