WSDOT planning repair to open SR 4 on KM Mountain

No public logging road detour around slide: Wednesday meeting cancelled

 

January 23, 2020



Washington Department of Transportation engineers hope to have a single lane of traffic open soon around the slide blocking SR 4 on KM Mountain.

"Soon" is probably next week but possibly as early as late this week.

District Construction Engineer Christopher Tams said Tuesday he has hired a contractor to begin removing trees and other debris that have blocked the highway since last Thursday afternoon. Crews would mobilize Tuesday and Wednesday at each side of the slide and begin working toward each other, he said.

The rate of progress will depend on how stable the slope is and how potentially heavy rainfall predicted this week impacts the site.

Tams anticipates that once the site is clear, crews will place container boxes along the edge of the far lane of traffic to protect travelers from potential new slide activity. The crews would install a rock buttress similar to that anchoring another slide site just down the hill from the current slide.

"We're fortunate it's in a passing zone and we have three traffic lanes to work with," Tams said. "My hope is that by the end of the week we'll be able to open one lane."

Meanwhile, local officials and agencies are working out ways to deal with providing service on each end of Wahkiakum County.

Logging road detour

On Tuesday, the Wahkiakum County board of commissioners authorized Chair Dan Cothren to sign road use agreements with four private property landowners for limited, authorized vehicle use of logging roads to travel between the east side and the Westend without have to use US 30 in Oregon.

The routes use logging roads that are gated and not open to the public.

The roads aren't suited to most passenger vehicles, said Stephan Dillon, Columbia River Region Manager for Hancock Forest Management, one of the four landowners. He said vehicles need to have four-wheel drive and 10-ply tires. The gravel roads are susceptible to washouts, he added, and falling limbs and trees are a danger in windy periods.

However, vehicles are trying to use the routes, said commission Chair Cothren, who is also employed as Hancock's forest security manager.

Cothren said he encountered a family vehicle on Monday trying to find the route; the driver insisted they could use it because it showed on their GPS. They were turned away.

On Saturday, Cothren added, a vehicle with a family "somehow got inside the gates and were locked in for six hours."

Cothren added that a logging road route that was paved and used for a detour when another slide blocked the highway for approximately 20 months in 1990-91 has deteriorated since then and has places where it has eroded away.

Health department adapting

The county Health and Human Services department is finding ways to continue transportation and mental health crisis services in the Westend, which is cut off from department headquarters in Cathlamet.

H&HS Director Chris Bischoff said Tuesday the department is exploring the possibility of Pacific County Mental Health taking over crisis service until a route is open around the slide. Crisis responders may be able to team with sheriff's deputies responding to calls in some situations. The slide has also severed routes for the Wahkiakum on the Move bus system, Bischoff said.

Staff are exploring what they can do to provide some service from the Westend, and they are also consulting with Pacific County Transit about possible temporary service to Johnson Park in Rosburg.

"These are very expensive options," Bischoff said. "We don't get extra money for those routes."

Wednesday meeting cancelled

Commissioners on Tuesday cancelled a town hall meeting they planned to hold Wednesday at Johnson Park.

The commission tries to hold town hall meetings in the Westend every three months to gather input and discuss issues. On the agenda for this meeting was a proposal to lower the speed limit through Grays River to 45 miles per hour.

WSDOT using past, present knowledge

WSDOT staff were able to survey and map the site with a drone aircraft, Tams said, something they haven't been able to do at past slides.

That allowed geotechnical engineers to start planning a response to clear the slide and stabilize the slope, he said.

The slide is approximately 350 feet long and extends uphill from the roadway 175 feet, he said.

"We noticed other areas with tension cracks," he said, "and that's one of the other things we're evaluating."

Two factors work in the engineers' favor, Tams said: The slide ends at the road bed, which is stable, and during the response to the nearby 2007 slide, geotechs gathered a lot of data for core drilling that will assist in planning a response to the current slide.

"It may be weeks or a month before we get the whole thing done," Tams said. "Ultimately, when we do the fix, it will look like the repair nearby from the 2007 slide."

Tams added that engineers can't determine the potential impact of logging on the slide. The slope above the current slide was recently logged, and the slope above the 2007 slide was forested at that time.

 

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