The Illinois Department of Natural Resources (IDNR) will delay the traditional April 1 opening of Heidecke Lake in Grundy County to boaters this year because of unusually low water levels caused by ongoing drought conditions.
IDNR staff will continue to monitor the lake and will reopen it once it reaches safe navigation levels, the department said in a Monday news release.
“The department expects levels to return to typical ranges as normal precipitation patterns resume. IDNR is evaluating potential options for adding water to the lake if drought conditions persist,” the release said.
Heidecke Lake is located near Morris and is a former cooling lake for a power generation plant. IDNR leases the site to provide public outdoor recreational opportunities.
This marks the first time since the utility site was decommissioned in 2007 that water levels at Heidecke Lake have dropped too low to allow safe navigation by boats and other watercraft, the IDNR said.
Current water levels are about 506 feet, 11 inches above sea level. Ideal water levels for the lake are about 510 feet, with safe navigation for watercraft typically possible at 508 feet or higher, the release said.
According to the National Weather Service, north-central Illinois has experienced significant precipitation deficits, with the region 8 to 15 inches below normal precipitation levels since Oct. 1, 2024.
In addition, 2025 ranks among the top 20 driest years on record for the region. The Heidecke Lake area also experienced 29 days with temperatures exceeding 90 degrees – 14 days above normal, according to the IDNR.
“These conditions have contributed to reduced water levels in lakes, rivers and other bodies of water throughout the region,” the release said.

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