ANKENY—At 7 a.m. this morning, DNR began receiving reports that a tributary to Fourmile Creek in Ankeny had turned white and that fish were struggling near the surface.

DNR staff and city of Ankeny officials responded, tracing the white color back through a storm drain to milk released at the Hy-Vee store at 410 N. Ankeny Boulevard.

DNR is working with Hy-Vee to prevent the milk-laden water from reaching Fourmile Creek on the northeast side of town. One option under consideration is building a series of small dams and vacuuming up the water. Hy-Vee officials determined 800 gallons of milk were released.

DNR staff have not seen any dead fish. However, as bacteria break down organic products the bacteria use up oxygen. Particularly in small streams, low oxygen levels can kill fish and aquatic organisms like crayfish and insects.  

“Materials that we think are harmless can actually be very toxic to the environment,” said Ted Petersen, DNR supervisor. “When disposing of a liquid into the municipal collection system, it’s important to check with the local wastewater treatment plant or DNR field office prior to disposal.”

DNR is monitoring cleanup activities and checking the stream for a fish kill. The DNR will consider appropriate enforcement action.