Morning Call: September 30, 2004

Real solutions only come after the real problems are determined. Finally, it sounds like someone in the state Department of Transportation is beginning to spell out what many in the Lehigh Valley have suspected about the sinkholes that have undermined the two Route 33 bridges in Stockertown. A nearby limestone quarry is a contributing factor.

Last week Gary Hoffman, deputy secretary of operations for the state Department of Transportation, said, "We know that the quarry is unquestionably a contributor. But to say it is 50 percent, 60 percent of the problem or 90 percent of the problem, I think none of us can say that."

You don't have limestone quarries -- the raw material used in making cement -- without having limestone. And sinkholes are a common occurence where there's limestone. Groundwater dissolves the underground limestone and holes open up.

But more important than finally affirming people's suspicions, Mr. Hoffman admitted PennDOT's own failings. He said it was PennDOT's fault the northbound Route 33 bridge over the Bushkill Creek failed because the department didn't properly design and build the bridge in the 1970s to survive the area's porous geology. In the current reconstruction, both bridges' supporting piers are being built on solid bedrock.

The Route 33 corridor is a major gateway to the Lehigh Valley's future economic development. The region can't afford that future to be riddled by sinkholes. Making sure it doesn't happen along the highway is first a safety issue but it's also a crucial development concern.

Officials are considering lining the creek in the bridges' vicinity to help prevent future groundwater problems. But study needs to determine if that will cause worse sinkhole problems for downstream residents. But understanding the connection between quarry operations and the so-called "zone of influence" should prompt state reviews of permits to dig deeper there. The more all the factors that caused the problem are understood, the better the ultimate solutions will be.