In late June, we experienced another fresh water mussel kill in Swan Lake. Mussels also were dying in Wildflower Lake which is part of the Old Farm Lakes Gardens subdivision. We estimate the loss of 20,000 mussels in Swan Lake. Fortunately, no fish kill occurred. The pattern and date are almost identical to the mussel kill that occurred last year. The OFLPOA Board notified the Illinois EPA and they sent agents from the Champaign and Peoria offices to investigate.

As with last year, a property owner in the Colonial Meadows subdivision sprayed Roundup around a wet retention basin in Colonial Meadows. When it rains, water concentrated with Roundup chemicals releases into Wildflower and Swan lakes.

The EPA agents spoke with the property owner spraying the Roundup and requested he stop spraying Roundup around the retention basin. The retention basin for the entire Colonial Meadows subdivision is practically right in the front yard of this property owner. He cannot get the city or township to control the weed growth in and around the basin. For health reasons, this property owner is unable to control the weed growth by just cutting them down. The property owner did agree to stop spraying the weeds so we can determine for sure that the Roundup spraying is the cause of the mussel kills. The Board offered to help the property owner in the future in his efforts to get the city or township to manage the weed growth without the use of chemicals are unsuccessful.

In 2013 we experienced a very large mussel kill, estimated to be 100,000 mussels. At that time, it was noted that weed killer was sprayed around a wet retention basin in a different upstream subdivision. Water from that basin also overflows into Wildflower and Swan lakes when it rains. The EPA said they would contact that homeowners’ association and request they refrain from spraying chemicals around their basin in the future.

The EPA is not certain the spraying of the weed killer into upstream water retention basins is the cause of the mussel kill. But the timing of all three past events point to this possibility. However, by the time we notice the mussel kills, several weeks have passed since the application of the chemicals and water samples taken after the mussel kill occurs no longer contain the chemicals. To be effective, water samples need to be taken soon after the chemicals are applied and water flows into Wildflower and Swan lakes.

We are hopeful if the upstream spraying stops, the mussels dying off in large numbers will also cease.