Sunday, December 28, 2008

Is the City of Portland Responsible for the West Hills Landslide?

In the early morning hours on October 8, 2008, an unimaginable event transformed the landscape of a well-established Portland West Hills neighborhood. When the slope collapsed underneath the home on 6438 S. W. Burlingame Place, it became a swift-moving mass destroying two homes and significantly damaging several others. The companies providing insurance for the injured parties have so far declined coverage for the landslide property losses.

Portland officials have ruled out rain and leaking city water and sewer lines as possible causes of the slide. The Oregonian reported on November 21, 2008 that the primary suspect appears to be a sprinkler system that was installed on the back yard slope where the landslide occurred. Portland Commissioner, Randy Leonard, told the press “What has changed to cause the soil conditions to become so malleable that what had held for 75 years broke loose? What’s different is the installation of an irrigation system combined with an unusually high use of water.”

Records indicate that the property owners, Kathei and David Hendrickson, received a city permit to install the system in March 2005. The City of Portland Natural Resources information website shows that the Burlingame property was located on a slope greater than 25% and subject to landslides and soil erosion.

Bill Burns, an engineering geologist for the state, said he believed the slide was likely caused by several factors: water in the soil, unstable ground and the steep slope the house was erected upon.

The Portland metropolitan area experienced disastrous landslides in February 1996. Geologists found that the West Hills Soil Province suffered hundreds of slope failures during this wet-winter period. Soil sediments, which cover the area, are stable construction sites when dry but are dangerous when saturated.

The Hendricksons have lost their home and they are facing numerous long-term lawsuits. No one has yet determined the trigger for the landslide, whether manmade or natural. The city has denied all responsibility for the slope failure and resultant property damage. It should be noted that if the sprinkler system is found to be the cause of the landslide the city granted the permit.

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