Mysterious hole behind Johnson County Courthouse solved

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

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 - a limestone well, or cistern, yawned beneath them.

“All you can do is just shake your head,” said David Kempf, the county's facilities manager.

He said crews 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 the cistern is 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. He and others looked into the cistern, hoping to find something like old bottles, but there was nothing but dirt and grubs, Kempf said.

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 a dump truck's worth of gravel down the hole and ran a couple of thousand gallons of water in it to settle the rock, Kempf said.

Last summer, another recurring pothole in the parking lot north of the nearby county jail revealed the basement of an old house when workers started digging around it.

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