An underground sewer main broke just north of Riverside Park on Saturday, releasing roughly 42,000 gallons of untreated sewage into the La Crosse River, officials said.
The pipe, which is a force main, or a type of underground pressurized pipes that moves untreated sewage long distances, was transporting the sewage toward the city of La Crosse’s wastewater treatment facility.
The main break occurred on the northern bank of the La Crosse River where it meets the Mississippi River, just north of the park.
The leak was discovered after a pedestrian walking through Riverside Park notified the Wisconsin Department of Natural Resources of untreated sewage floating at the surface of the water.
City staff was notified of the leak at 12:25 p.m. on Saturday, and were able to stop it at 3:30 p.m. by closing a valve, diverting the flow of the sewage into a second force main, which officials said can handle the additional flow.
“We have some time to get this fixed,” said La Crosse Utility Manager Bernie Lenz.
Officials said crews are working to evaluate the damage to determine the best fix, which would likely go through emergency authorization through the Board of Public Works.
The environmental impact of the leak is expected to be low, officials said, citing that the ratio of sewage leaked to the flow of the river was “minimal,” diluting much of the raw material.
The time of year also worked to limit environmental impacts, officials said, noting that there are no spawning fish at this time, and the cold weather, all played a factor.
“Consider what runoff from farm fields does to the [La Crosse River] every time it rains as compared to this minor incident for” perspective, Lenz said in an email to the Tribune.
Residents are asked to avoid contact with the water in the La Crosse River near where the leak occurred.