Mystery hole found at Johnson County Courthouse

IOWA CITY - The case of the mysterious pothole behind the Johnson County Courthouse has been solved.

Left behind, though, is a mysterious hole.

Last month county crews set out to figure out why a pothole on the courthouse driveway kept recurring. They'd fill it up with gravel, and that gravel would eventually go away.

With the help of a contractor, they started breaking up the concrete and digging. All of a sudden, the bottom of the hole fell away. Concerned about their safety, workers rushed back. When they looked down, they got a surprise.

There they saw a limestone well or cistern.

David Kempf, the county's facilities manager was there.

“All you can do is just shake your head,” he said of his reaction. See Kempf's photos below.

They tied a hammer to the end of a tape measure and sent it down the well/cistern. It was 22-feet deep and 4 feet across.

Kempf guessed it to be as old as the 110-year-old courthouse or older.

The old county jail used to be behind the courthouse, and Kempf said the hole may have been a cistern that a roof drain went to.  They looked down in it hoping to find something like old bottles, but there was nothing but dirt and grub. He said he wasn't about to send anyone down there because of safety concerns.

The old courthouse used to be on that site too, said Leigh Ann Randak, curator at the Johnson County Historical Society. It was built in the 1850s, and Randak said she would guess that it had a well. 

Whatever its age and purpose, the hole is no more. The county put nearly an entire dump truck's worth of gravel down it and ran a couple of thousand gallons of water in it to settle the rock, Kempf said. No more recurring pothole.

While the find was odd, it's not unheard of. Last summer, there was another recurring pothole, this one in the parking lot north of the nearby county jail. Workers started digging around it and found the basement of an old house.

Kempf said it appears someone knocked the house down and burned it. Workers pulled out an old wood-burning stove and chunks of furniture. They filled that hole back up too.

Kempf said he probably shouldn't be surprised anymore by what they find. 

“Iowa City's getting to that age where you've got second- or third-generation building on sites” that were developed before, he said.