A state investigation has found the fish kill in Wildcat Creek last month, in which over 2,000 fish were found dead, was likely caused by a one-time discharge of chlorine in Foster Park.
The Indiana Department of Environmental Management launched the investigation on Aug. 21 after a resident reported seeing cloudy water with “a strong bleach smell” entering the creek from a large storm sewer in Foster Park.
A short time later, workers with the city’s storm water department observed some dead bottom feeding fish near the storm sewer outfall.
When investigators arrived, the water discharging from the storm sewer was clear, colorless and there was no noticeable odor, according to the report. Field tests for dissolved oxygen, chlorine, ammonia nitrogen and other chemicals all showed normal levels.
The next day, another resident reported seeing dead fish approximately 1 mile downstream from Foster Park. Investigators again performed field tests with similar results as the day before.
After the reports were made, the Indiana Department of Natural Resources discovered a total of 2,040 dead fish, including 597 small mouth bass, 879 suckers, 502 minnows/chubs, 31 freshwater drum and 31 carp.
A two-week investigation followed, in which state and local officials talked to area businesses, as well as the Kokomo Parks Department, about any discharges that may have contributed to the kill.
Officials ended up talking to a contracting crew working on water lines on Morgan Street, which has storm sewers that lead to the creek, who reported using dechlorination tablets before the fish kill. Those tablets remove chlorine and chloramines from wastewater, potable water and processed water.
IDEM investigators concluded that they suspect the cloudy materiel with a bleach odor was from a one-time discharge, as the water was clear, colorless and odorless when investigators arrived soon after the report was made.
“It is possible the air and water temperatures, along with sunlight, caused the suspected chlorine to dissipate and be undetectable by available testing equipment,” the report said.
IDEM said there have been no new reports of injury to the creek, and that Kokomo officials will alert them to any new information regarding the incident.
The investigation comes after a failing lift station near the American Legion Golf Course last August leaked raw sewage into the water, resulting in a fish kill that impacted around 1 mile of the waterway.
In that incident, city crews spent five days pumping and aerating sections of the creek to remove the chemicals and sewage that led to the kill.