Spokane outlines plan to prevent Peaceful Valley landslide

Months after a landslide forced the closure of Clarke Avenue, city officials are ready to implement a permanent fix.

The city plans to install specialized geotechnical reinforcements and a new retaining wall on the north side of Clarke Avenue before the end of the year.

If all goes according to plan, Clarke Avenue could soon reopen for the first time since officials noticed the steep Peaceful Valley hillside was unstable following a powerful January windstorm.

“I’m going to do everything I can to get Clark Avenue open for the wintertime, as long as it’s safe to do so,” said Kyle Twohig, the city’s director of engineering.

To fund the project, officials are asking the Spokane City Council to pull $2.1 million from reserves, although they expect the Federal Emergency Management Agency to reimburse up to 75% of that.

Twohig outlined the plan in a presentation to the City Council’s Public Infrastructure and Environmental Sustainability Committee on Monday.

The project will include installing geotechnical nails that will “basically pin the whole hillside down right through the slide plain itself,” Twohig said. The retaining wall at the bottom of the hillside, which failed, will be replaced.

Twohig said the city has met several times at the site with FEMA representatives.

“They were very pleased with everything we’ve done … Our likelihood of receiving a significant chunk of that money back from FEMA is very, very high,” Twohig said.

The city hopes to get the project underway just as wet weather arrives in Spokane, which Twohig described as a “concern for us,” as moisture can destabilize soil.

The city is one of three property owners potentially included in the work. It expects to sign reimbursement agreements with two nearby property owners for work done on private parcels, including one with a condo association based atop the hillside.

“Personally, I’m really excited that they are choosing to do this. It is certainly their choice, and they’re going to be investing significantly to stabilize that hillside as well,” Twohig said.