WTAE-TV - Channel 4
Oct. 28th 2008
CLINTON, Pa. -- It's not close to being cold enough for the rivers to freeze, but the Army Corps of Engineers says ice packs this winter may lead to the failure of a dam along the Allegheny river.
There is a severe problem hiding just under the waters going over the dam at Lock 6 near Clinton in Armstrong County. But Army engineers are working to make sure it doesn't give way to a multimillion-dollar problem.
Inspection divers discovered a 200-foot stretch of severe erosion along the 80-year-old dam, starting from the hydro-power plant on the opposite shore.
"The riverbed material has washed away. So now, all we have are these timber piles sticking up out of the river bottom, with a big hunk of concrete on top of them," said Army Corps Project Manager Jeff Fritz. Fixing it right away could cost $1 million to $5 million. If it fails, the job could end up costing $20 million and take six months to complete.
The 30-foot-long supports driven into the riverbed years ago, support the concrete structure of the dam. With erosion, 18 feet of those supports is now exposed. The bump of a barge or a big block of ice could tip over that section and bring the concrete of the dam down. "It's like a person walking around on stilts. You got these two poles under your feet and you're trying to balance on these sticks 18 feet in the air," Fritz said.
Failure of the dam would not cause flooding. It would cause a river level drop for a 10-mile stretch, shutting down river traffic and could severely degrade water intake for plants near Kittanning. Dam failure could also make some wetlands in the area dry up. "And you'd have a gaping hole there between the hydro power wall that we're looking at and the other part of the dam," said Fritz.
Emergency repairs should start in mid-December and be finished by Christmas.
The area of concern along the dame will also be under 24-hour surveillance, to alert the crews to any problems before repairs are complete.
On Tuesday, the Port of Pittsburgh Commission released the following statement on the erosion at Allegheny Lock and Dam #6:
“The erosion at Allegheny Lock and Dam #6, and the danger it poses, is symptomatic of a long term problem affecting almost all of our locks and dams. While intelligent and annual maintenance would be the logical, proactive and efficient solution to maintain our aging navigation infrastructure, the historic lack of such funding is not only risky to commerce, but it is a much more expensive way of maintaining our waterways, clearly pennywise and pound foolish.”