Landslide closes Pleasantville Road in Harrison Township
By Chuck Biedka
Published: Thursday, November 1, 2012, 8:34 a.m.
Updated: Friday, November 2, 2012
Part of a state road in Harrison remains closed because of a landslide and experts expect continuing rain and the return of the freeze-thaw cycle will likely cause many more landslides across the Alle-Kiski Valley.
PennDOT closed Pleasantville Road, between Burtner Road and Juniata Street, early Thursday because of a rock fall. Although one lane was cleared, PennDOT is restricting traffic because there is the potential for more rock falls.
“Work will be scheduled to remove the material as soon as possible,” PennDOT spokesman Jim Struzzi said Thursday afternoon.Slides generally happen more often in Southwestern Pennsylvania than in other parts of the state, said Helen L. Delano, senior geologic scientist for the Pennsylvania Geological Survey.
So it's not surprising that landslides have been cropping up the past few days after more than 4 inches of rain fell over much of the region since Saturday.
And when temperatures begin to regularly drop below freezing at night but rise into the upper 30s and 40s during the day, water that has seeped into cracks in rocks will freeze, expand and thaw again.
“That causes landslides and rock falls,” Delano said.
Alicia Kavulic, manager of PennDOT District 10's geotechnical unit, said clay is often a factor, too.
Add steep hills and the region is “in the bull's-eye for slides,” said Randy Bookshar, a geography instructor at Penn State New Kensington.He said fixes are expensive, from attaching a chain link fence attached to an unstable hillside, bolting rocks together, to regrading a hillside.
The most massive, persistent and expensive to fix rock slide area in the Alle-Kiski Valley was along the Route 28 expressway just south of the Harmar exit (Exit 11). Four years ago, PennDOT spent $8.5 million to stabilize the hillside, install a fence to catch falling rocks in a drop zone and shift the roadway away from the steep hill.
And still, rocks continue to fall, most notably in August 2011 when a 300-pound boulder struck a Lower Burrell man's car.Last summer, PennDOT scheduled 19 slide repairs in Allegheny County alone because of 2011 storms, Struzzi said.
PennDOT District 12, which includes Westmoreland, Washington, Greene and Fayette counties, has the largest number of slides in the state, according to spokeswoman Valerie Petersen.
Accordingly, it spends the most annually to repair landslides — about $1.7 million.
Keeping up with them can be difficult. About two-thirds of the 84 embankment failures in District 12 will be under contract or repaired by the end of next June, she said.
Slides of another type have bedeviled PennDOT in Armstrong County.Two slides closed Margaret Road off Route 422, said PennDOT spokeswoman Deborah L. Casadei.
“Here, the slides were under the road and we had to close the road for several days,” she said.
It took about $260,000 to fix those problems, officials said.
Chuck Biedka is a staff writer for Trib Total Media.
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