DNR officials say that the Rock Rapids City Operator noticed there was no inflow to the Rock Rapids Wastewater Treatment Plant about 4 p.m. Tuesday, indicating a broken pipe or other problem.
By 7:30 p.m. Tuesday, the city had rerouted wastewater to a holding basin used during high rainfalls.
According to the DNR, Wednesday, the city and DNR traced the leak to a break in an 8-inch force main underneath the Rock River. The city estimates 56,000 gallons of wastewater discharged into the Rock River, moving rapidly downstream.
The Iowa DNR will continue to monitor cleanup and repairs. They say there was no evidence of a fish kill; however, downstream livestock producers who have cattle along the river may want to provide an alternate water source for 24 hours.
There is no estimate on how long it will take to replace the original 1950s-era force main.