Mudslide cause for emergency repairs

Slides, flooding off of 92nd damage property
By Sara Bruestle | Jan 09, 2013
Courtesy of: Christine Awad Schmalz A top view of a mudslide that occurred last month off of 92nd Street S.W. between 62nd Place W. and 63rd Place W.

The city declared an emergency Monday following a break in a storm line in December just off of 63rd Place W.

A mudslide occurred on Dec. 17 near the intersection of 92nd Street S.W. and 63rd Place W. that pulled a storm line from a catch basin, causing water to spill out and add to the slide.

The same hillside had failed in 2011 due to a major mudslide, disrupting a sewer main line and power lines. Crews had restored the hill and moved power lines – but it didn’t stick.

On Monday, Mukilteo City Council approved an emergency contract with KLB Construction for $25,000 to make the repairs in December.

The temporary fix from the Dec. 17 slide was put in place within two days: Pumps were installed to pump stormwater past the failure, new pipe was slipped into the ends of the old one, and the slope was covered in plastic to keep precipitation levels low.

If it hadn’t been fixed quickly, more of the hill off of 63rd Place W. could have slid, again putting the sewer line and power feed at risk, said Public Works Director Larry Waters. Another slide also could have “severely damaged” a nearby home, Waters said.

Waters said he recognized that the line break threatened the whole stormwater system there and had Public Works crews take the lead.

A more permanent fix for the slide will be determined by the summer, Waters said.

The Dec. 17 mudslide wasn’t a lone disaster: Within the last month, about 10 mudslides were reported in the city.

“We think much of what we’ve seen here is because of the huge rainfall we’ve been having,” Waters said. “We had 8 more inches of rainfall in October-December than we normally have.”

“It just seems like in the last five years, things have been getting wetter and wetter,” he added. “With development, it gets wetter too, even with all the storm water systems we get in place.”

Many of the slides occurred in the neighborhoods off of 92nd Street S.W. Half of 92nd remains closed as a result of a major slide between 61st Avenue W. and 62nd Place W.

Two slides also occurred above the access road to the Big Gulch Water Treatment Plant.

Public Works crews have been involved with seven of the slides, either cleaning them up or helping homeowners cope with the damage. State crews cleared several others on the Mukilteo Speedway.

Some of the fixes are still in progress, including the slide on 92nd Street S.W. The city has hired Zipper Geo Associates for $5,000 to help with slope evaluations and repairs.

Councilmember Steve Schmalz, who lives near 92nd, has gone door to door to talk to his neighbors and get an idea of how bad the flooding and sliding has been. Some said their homes had flooded.

He said he’s concerned that a lot of the flooding occurred because of bad drainage systems in new residential development nearby.

“Folks off of 92nd and 53rd were pumping water out of their backyards for hours on end due to unforeseen circumstances,” Schmalz said. “I think that’s due to new development.”

Schmalz said the city should create a fund specifically for dealing with mudslides. He said Mukilteo does have an Emergency Fund it can tap into, but that he’s not sure it’s enough.

“There are going to be years where we don’t have any issues at all,” he said, “but if we put money aside, when something does happen, it won’t be that painful.”

Here are just some of the slides that occurred:

Slides blocked part of the ferry lane near the 1000 block of SR-525. Two blocks away, another mudslide struck a car and took out part of a resident’s garage.

A mudslide covered both lanes of 61st Place W. Another slide near the intersection of 6th Street and Washington Avenue threatened some power lines, and a pole had to be replaced.

Waters said a common cause of mudslides near homes located on bluffs or ravines is that residents have the “bad practice” of throwing leaves and lawn clippings onto the slopes.

“It kills plants underneath, soil keeps wetter and it adds a lot of weight to soil that wasn’t there before,” he said. “That is kind of a triple whammy.”

Waters said that any residents living on a bluff or a ravine need to manage the stormwater around their homes so that it doesn’t saturate the slope. If they don’t, he said, it’s only a matter of time before the slope slides.

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