The night of April 16, as clouds dumped nearly five inches of rain in Lower Allen Township, Suzette Beemer watched part of her Cedarhurst Lane backyard disappear.
It was swallowed by a sinkhole, maybe 40 feet long, in some spots a dozen feet deep. Water spouted out of one hole and drained into another as the land between them sank.
“It was very scary,” she said.
She and her friend Jerry Boscaccy checked on it periodically through the night, aiming flashlights its way, until Boscaccy fell into the widening hole, and they decided it had become too dangerous.
Beemer thinks the township should pay to repair the hole. Neighbors told her the township had repaired sinkholes on a facing property on Rockaway Drive a few decades ago, filling them with cement and diverting water toward her backyard.
Township manager Tom Vernau, however, said there is no record of the township doing any work there, and it would be unlike the township to fix sinkholes on private property.
He said Rossmoyne Manor, the development where Beemer and Boscaccy live, was built in 1955 and has a very rudimentary stormwater system, put in either by the original developer or shortly thereafter. It used cisterns, and when they overflow the extra water is shunted through pipes into yards.
The whole area is underlain by karst limestone, making it prone to sinkholes, he said.
He said it is possible the sinkholes filled with concrete on Rockaway Drive could have diverted water toward Cedarhurst Lane. Concrete “doesn’t give water anyplace to go,” he said.
These days, a better fix is to excavate the area, plug the hole with larger rocks, then use layers of increasingly small rocks to fill, followed by a textile material, topsoil and grass. That allows the water to trickle down through the rocks instead of gushing through and washing out a hole.
Central Pennsylvania is prone to sinkholes. Last week PennDOT filled a sinkhole on Route 422 in North Londonderry Township for the 15th time since 2009, for a total cost of nearly a quarter million dollars.
Beemer said an excavator told her their sinkhole is likely to cost about $12,000 to repair, but he won’t really know until he starts excavating. A large old maple which has provided cooling shade for years is poised at the brink of the sinkhole and will have to come down, Boscaccy said.
It is not unusual for sinkholes to lead to lawsuits as the parties involved try to establish blame.
William Kochanov, a senior geologist with the state Department of Conservation and Natural Resources, said in an interview last year that underground water systems are complex. He said sinkholes are like drains in a plumbing system that are clogged with soil until water flushes the soil and a hole opens.
Development, abandoned pipelines or septic systems, even old tree roots can change the underground plumbing, he said.
Lawsuits over sinkholes are common throughout the country, as sinkholes can be expensive to repair, Kochanov said. Although they might not have the economic impact of a flood or a hurricane, “they can nickel and dime their way into millions of dollars.”
Vernau said the township might look into installing a better stormwater system in the area, trying to pipe excess water toward an existing system on Slate Hill Road. He didn’t know when that might happen.