LAKE FOREST PARK — The Lake Forest Park City Council voted June 26 to move forward with designing a fix for a landslide that has closed Forest Park Drive to most traffic since 2001.
Landslides occurred on Nov. 21 and Dec. 14, 2001 beneath the road as it curves around an embankment during a particularly wet rainy season. The slides happened in the section of roadway that is located just below the Cherry Hill Apartments, between 19th and 25th streets NE.
According to city engineer Neil Jensen, a geotechnical study released by consultants in May 2002 determined that to repair the roadway, a mechanically stabilized earth wall needed to be built and a drain system needed to be installed to channel groundwater away from the subsurface.
“The problem you have with this unstable roadway is that there is a hard layer of clay about 20 feet down and when groundwater moves through this area, it collects on top of the clay because it can’t go down any further,” Jensen said.
“When that happens it saturates the area and everything above it becomes unstable. So as more weight is added as a big storm comes through, everything sitting on top of the clay is at risk of sliding.
“Building a new drain system to channel the water away will take care of the underlying cause for the slide,” he said. “And by using geotextile fabrics in building up the earth wall beneath the road, it causes the entire roadbed to act as one stable unit.”
The Council must decide if the city should build an asphalt pavement shoulder with a guardrail or if it should also build a sidewalk, curb, gutter and handrail.
Total estimated project costs are $404,000 and $428,000 respectively, Jensen said in a memo to the Council. The Council has $300,000 budgeted for the project.
The consultants advise against constructing the project in the rainy season, which begins approximately in October, so it is not possible for the project to be completed this year.
The goal is to begin design and property right acquisition this summer and aim for construction to start in June of 2004, Jensen said.
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