City closes sidewalk due to landslide risk

April 12, 2011

By Warren Kagarise

Groundwater seeps through the timber retaining wall, and a pedestrian sidewalk is closed along Southeast Black Nugget Road at Southeast 62nd Street. By Greg Farrar

The chain-link fence erected along the Southeast Black Nugget Road behind Fred Meyer and The Home Depot raised questions among motorists concerned about possible landslides.

City Public Works Engineering Director Bob Brock said municipal crews added the fence late last month as a precaution amid the risk for small landslides. The city is also addressing long-term issues related to the retaining wall along the same stretch.

“We’re trying to investigate what we can do to stop the earth movement above the wall, which is a separate issue from the wall itself,” Brock said. “The wall is in no danger of coming down, it’s just that it’s got a reduced lifespan because of some of things that were not done per plan.”

Instability on the slope is common after soaking rains, but city officials said the slippage does not pose a risk to the residences perched above Southeast Black Nugget Road. Way Back Inn, a Renton nonprofit organization, owns the land on the slope.

“It seems like this year, we’ve had a lot more water. It’s moving a little bit more and it’s got some fluidity to it that it didn’t have before,” Brock said. “So, as a precautionary measure, we closed the sidewalk just on the off chance that something might fall over the top of the wall there.”

Crews also planted stakes in the hillside to track shifts in the slope. The fence and the stakes attracted attention from Klahanie resident Sandi Dong.

“My husband actually told me he preferred that I stop using Black Nugget, behind the Fred Meyer store, because of the evidence of land movement,” she said. “For the past year or so I’ve actually avoided the road and drive all the way down Issaquah-Fall City Road to East Lake Sammamish.”

Brock said the city is also addressing separate issues about the Southeast Black Nugget Road retaining wall.

The structure needs temporary construction in order to better brace against the slope.

“The look of the wall is pretty ugly, but that isn’t the real issue,” Brock said.

The problem is the reduced lifetime for the wall. Typically, such a structure might be built to last 75 years, but problems during construction mean the lifespan could be reduced by as much as half, Brock said.

The city annexed the slope and the surrounding area in the 2000 North Issaquah annexation. Because the annexation occurred after development already started in the area, the county continued to handle the builder and conducted inspections.

Brock said city leaders hope for some county funds to help offset the repair cost. The municipal Public Works Engineering department also requested city dollars to complete repairs.

In the municipal budget, city leaders called for engineering design work to continue throughout 2011 as a prelude to needed repairs for the structure.

“We’re trying to work out what needs to be done there to make it not have the issues that it’s having right now,” Brock said.

Warren Kagarise: 392-6434, ext. 234, or wkagarise@isspress.com. Comment at www.issaquahpress.com.

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Comments

2 Responses to “City closes sidewalk due to landslide risk”

  1. Steve on April 18th, 2011 10:42 am

    Please tell me that I didn’t just read that city and county dollars will pay for this repair! Where is the builder?

    “Typically, such a structure might be built to last 75 years, but problems during construction mean the lifespan could be reduced by as much as half, Brock said.”

    What problems? If they were known, then why weren’t they mitigated? Again, go get the builder.

    This is not even debatable: It doesn’t take an engineer to know you are not going to get 75 years by bracing a 30-foot wall of seeping mud at the bottom of a steep grade using treated wood. My wife and I have been avoiding this area and watching the slope slide since construction. And now, if we have to pay one cent into this farce, then I expect my family to have a voice in all future slope stabilization designs, because I assure you that even my toddlers playing in their sandbox can come up with a better design and choice of materials than this.

    What was supposed to happen after 75 years, anyway? Certainly the condos above and adjacent to the slope were built to last longer than that. OR WERE THEY? Hmm, the plot thickens…

  2. Landslide poses risk to Squak Mountain neighborhood’s utilities : The Issaquah Press – News, Sports, Classifieds in Issaquah, WA on April 22nd, 2011 7:20 pm

    […] soggy spring also caused a landslide on the North Issaquah slope behind Fred Meyer and The Home Depot. Other Stories of Interest: […]

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