The 3,800-acre master-planned community named SunCrest is expected to have up to 3,800 homes at build-out - so far, about 650 have been built. However, geotechnical experts are recommending caution because the area contains a massive ancient landslide.
"The age of a landslide means nothing," said Gary Christenson, spokesperson for the Utah Geological Survey, during Tuesday's presentation. In other words, ancient doesn't mean dead.
The bottom line, Christenson said, is that all existing landslides should be considered marginally stable.
"Nearly all historical landslides are reactivations of existing landslides," he said.
SunCrest's developer, a national firm named Terrabrook, invested $1.5 million into geologic studies to determine the best way to build on Traverse Ridge. To be on the safe side, Draper city officials have sought second and third opinions.
A recent city-funded report from Oregon-based Landslide Technology warned of the area's massive ancient landslide. It also brought the threat of a lawsuit from SunCrest's attorneys, which was later withdrawn.
However, city officials considered the LT report a wake-up call to examine the issue further.
Christenson showed examples of last spring's landslides in Mountain Green, Layton and South Weber. In those locations, the requisite studies had been done, indicating the land was stable enough to build on, he said.
"If you can't open doors or windows, those are some of the first signs of movement," said Christenson. "Then [structural] cracks start to show."
Both homeowners and municipalities suffer significant financial loss when landslides damage existing structures and utility lines, Christenson said.
SunCrest homeowner Danette Crowther attended Tuesday's presentation to get educated about the risks.
"If we are at danger in the future, what are the city's plans? And will our property values drop?" queried Crowther. "You take a risk, putting your money into your dream home - and you hope for the best."
Christenson recommended keeping a close eye on changes in groundwater levels - one factor that can trigger a landslide.
He also suggested that cities have landslide emergency plans in place.
"It's sobering when you see that kind of damage to a home - the impact to the homeowner can be devastating," said Councilman Jeff Stenquist.
Councilman Bill Colbert, a SunCrest resident, said he was assured several years ago that "you don't have to worry about ancient landslides."
"Since then we've been proven wrong. What can we do to protect investments and the community?" he asked.
Enforcement of grading codes is one option, Christenson said, third-party reviews are another.
The issue merits further discussion at a later date, concluded Mayor Darrell Smith.
cmckitrick@sltrib.com
