Statement on Valley Lake Fish Kill 8.20.2025
PSA:
The Wildwood Park District wanted to update the community regarding the fish-kill event at Valley Lake. We are working with the Lake County Health Department and have been in contact with the Illinois Department of Natural Resources in efforts to identify the potential cause of this event and to assess current water conditions. Per the Lake County Health Department, they were able to take a dissolved oxygen (DO) reading at Valley Lake this afternoon which was reading at values of 1.5 mg/L of dissolved oxygen at the surface and down to 0.6 mg/L about a foot down. Typically, levels below 5 mg/L can begin to stress fish, so these low levels would contribute to a fish kill. Staff observed live fish as well near the surface, and that may be observed around the lake until oxygen picks back up because they’re trying to stay near the slightly higher oxygen levels.
There can be several contributors for the DO crash. In the summer, water temperatures are higher, and water holds less oxygen. In addition, heavy rain events, like the one that occurred on Monday) can bring in large amounts of organic material and can be oxygen-consuming, crashing the dissolved oxygen.
The Park District is also in remediation discussions with an organics company that we are looking to address the fish removal and disposal of tomorrow (Thursday, August 21st). Any Illinois Wildlife Removal and Remediation will be removing and disposing the fish offsite mid-day on Thursday, August 21st.
We apologize for any inconvenience this may cause and will continue to provide updates as these efforts progress. Further questions should be addressed to info@wildwoodparkdistrict.com or 847.223.7275.
