A large sinkhole has formed below an earthen dam in rural Fairfield County, Pleasant Township, Ohio.
Because if the undermining indicated by the sinkhole, County and state folks are at the site trying to relief the pressure so the dam does not give way.
Tony Durant moved in a 100 year old home on Tschopp Road near Lancaster nearly three years ago. He says last night’s storm caught them by surprise. “We woke up at three with the sirens going off and water in the pond and everything was fine. Woke up this morning there was water in my basement and the pond was very high, so it just came quick,” said Durant.
“The hole was there when he woke up around 7 a.m. Since that time, it had grown about five times in size.” Durant said.
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The culvert from the lake feeding under the earthen dam is making a high-pitch noise, as millions of gallon of water are pulled underground. Officials speculate the culvert gave way under the enormous pressure, eroding and collapsing it from the force and making the sinkhole below the dam.
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The Fairfield County EMA Director Jon Kochis said the storm overnight is the cause of this breach.
It is a class 4 dam.
A Class IV Dam must meet the following:
Drainage area must be less than 150 acres.
Dam Height must be less than 15 feet.
Dam must not have the potential to impound more than 15 acre-feet of water.
Dam must pose Low Hazard potential.
Spillway capacity must safely pass the 24-hour 100-year frequency Type III storm plus 50 percent.
In 2015, Money is almost always an issue for private dam owners.
For the 15 years that Keith and Diane Derryberry have lived at Pine Lake Estates in Fairfield County, the dam that holds back its 12-acre pond has barely been a thought.
It didn’t cause the small homeowners’ association any trouble or cost them any money. That changed in 2012 when state inspectors found serious problems. The spillway pipe had corroded. One side of the dam was a foot or two shorter than the other side. And, most importantly, the 26-foot-tall dam was about 3 feet too short to handle flood conditions.
If the dam failed, it would wipe out Pine Lake Estates’ nearby campground and RV park and threaten the lives of its visitors.
Now, the dam is a money pit, needing as much as $1 million to meet dam-safety standards. The 40 or so homeowners who make up the association don’t have that kind of cash or that kind of credit, said Mr. Derryberry, the association’s president.
A year after that inspection, the association had failed to act. The state initiated an enforcement action — one of only 20 issued in the past five years. It ordered the association to drain the lake at least 4 feet to relieve pressure on the dam.
“You can see from the outflow enters the culvert, a 24-inch pipe and that is flowing full steady, so that is a lot of water outflowing from here and there are actually four lakes upstream from this,” Kochis said.
Because this dam and lake are private, the homeowner is responsible for the costs to relieve the pressure and repair the culvert.
“Meaning I have to put an emergency spillway in so they can dump this, so we don’t compromise the dam any more than it is,” Said Durant.
Pleasant Township firefighters are pumping water out of the lake for now, trying to relieve pressure on the dam, Durant says he’ll have to dig a trench around the dam and through his driveway to relieve it further. And official say that cost and repair of the culvert will be on him.
County authorities were called to 4165 Tschopp Rd. Wednesday morning for a failing dam. Being a private dam, state authorities could not deal with the hole that had formed just off the roadway from a flooded pond nearby.
Personnel from the Fairfield County Soil and Water Conservation District, Fairfield County Emergency Management Agency, Pleasant Township Fire, Fairfield County Engineer’s Office were all on scene monitoring water levels of the hole. The road remained closed throughout the afternoon just in case the dam broke.
Amy Boyer, district engineer/manager with county soil and water said that all they could do is monitor the dam.