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Views Are Changing on Landslide Risks

September 1, 2008

By Joseph M. Dougherty Deseret News

Over the past 10 years, geologists with the Utah Geological Survey have been working toward a paradigm shift in the prevailing thought toward development.

The perception among the geotechnical community, says UGS senior geologist Francis Ashland, was that landslides in Utah were prehistoric.

“The engineering community doing predevelopment studies hasn’t kept up with the science,” he said.

Since landslides began moving in the 1990s, UGS has had its work cut out for it in identifying geologic hazards.

Once a landslide has struck a home, homeowners have little recourse. Repairs are often so expensive that it’s nearly impossible to round up enough money or credit.

Some appeal the value of their property to their county to a value of zero or $1 so they don’t have the burden of property taxes. Some simply abandon their properties and end in foreclosure.

Some take action against their builders, as Mountain Green resident Brian Pugh did in July against Brett Simonsen Construction, which built his home on a area now known as the Creekside Drive Landslide.

And some homeowners plead with local governments to buy their property, which could sap a city’s budget in no time.

Homes up and down the Wasatch Front were destroyed by active landslides in 1997 and 1998, Ashland said.

And in wet years and most recently in 2005 and 2006, landslides claimed homes again. Mountain Green, Layton, South Weber, Bountiful, Draper, Pleasant Grove, Cedar Hills and Provo have seen or are seeing movement.

Some of those areas are growing quickly.

“There’s very little evidence that Utah’s landslide inventory has adequate stability to go and build on them,” Ashland says. “Almost every landslide we go onto is moving or moves each spring.”

So Utah Gov. Jon Huntsman Jr. convened a special geologic hazards working group in April 2006 to remedy issues cities face when developers come calling.

One of the recommendations of the geologic hazards group was a model ordinance cities could use in planning development.

That ordinance has been available to cities from UGS since early this year.

The Utah Legislature enacted a law this year giving cities the authority to regulate development in areas of potential geologic hazards to protect life or prevent the substantial loss of or damage to a property, as written in HB177, sponsored by Rep. Mike Morley, R- Spanish Fork.

Other recommendations from the governor’s working group included updated digital maps, which two teams of geologists will be working on at UGS, Ashland said.

One team’s work, compiling the state’s landslide inventory information on a wide-scale map, is already under way, he said.

The wider scale will help counties in knowing where landslides have existed and likely wouldn’t be useful for a single resident trying to identify whether a specific lot was in danger, Ashland said.

The other team, which UGS expects to hire, will create hazard maps on a narrower scale that will initially focus on the west side of Salt Lake County near the Oquirrh Mountains and on the southern cities of Herriman, Bluffdale and Draper.

“The current pace of development is challenging for us to keep up with it,” Ashland said. “What we’re trying to do is fill in the holes.”

Nothing like this has ever been done for western Salt Lake County, where UGS has learned of problems with collapsible soils, which lead to settling.

“Then they will start focusing on hot spots for rapid development, trying to keep ahead of where development is happening,” Ashland said.

Similar hazard maps for the Ogden Valley are expected to be available in summer 2009.

To learn more, go to geology.utah.gov.

E-mail: jdougherty@desnews.com

(c) 2008 Deseret News (Salt Lake City). Provided by ProQuest LLC. All rights Reserved.




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