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Wisconsin's surprising sinkhole situation: Unveiling the subterranean quirks of the Fox River Locks

Little Chute Lock
Posted at 5:28 PM, Nov 14, 2023
  • There is an unexpected prevalence of sinkholes in Wisconsin, located in the 160-year-old Fox River Locks system.
  • Phil Ramlet, the executive director of the Fox River Navigational System Authority, explains that the outdated construction methods contribute to around half a dozen sinkholes annually.
  • Despite the ongoing occurrence, Ramlet assures there’s no public danger associated with the current Little Chute Lock sinkhole.

(The following is a transcription of the full broadcast story)

I’m reporter Olivia Acree in Little Chute. When I think of sinkholes, Wisconsin isn't the first place that comes to mind. Until I learned that we actually get multiple a year, right in our backyard. The executive director of the Fox River Navigational System Authority explained that in a lock system that's nearly 160 years old, it's more common than you'd think.

“Through the years, water has found its way through the levees and the dams on the system,” said Phil Ramlet.

When the locks were built all those years ago, it was using construction debris, with no backfill or compaction like they’d use today and that’s left us with sinkholes.

“We end up with half a dozen sinkholes a year throughout the system,” said Ramlet.

They form over time, and Ramlet says it can happen pretty slowly and when one appears, they take care of it as soon as they can, so it doesn’t cause additional damage. Right now, they’re fixing a sinkhole at the Little Chute lock.

“We did this on an emergency basis so the contractor was out there, and we needed to act as soon as we could,” said Ramlet.

There are two ways they can fix a sinkhole. They’ll either backfill the hole with clay, or if it’s a bigger one, they’ll excavate out the bad material and fill it with new.

“We've been working on these for years and I'm sure that they're going to happen in the future as well,” said Ramlet.

Ramlet says there's no danger to the public associated with the sinkhole and that the fix should last forever. The current project costs around $57,000 and it comes from the Fox River Navigational System Authority’s around $16 million endowment.