In 2006, Illinois listed 10.69 miles of Cahokia Creek as impaired. 14 years later, Heartlands Conservancy's BMPs improved the stream, leading to delisting in 2020

For years, severe erosion and a lack of vegetation left parts of Cahokia Creek in southwestern Illinois struggling with poor stream conditions. In 2006, Illinois placed 10.69 miles of the creek on the Clean Water Act Section 303(d) list because of problems involving instream cover, streamside vegetation, depth and flow velocity, as per U.S. Environmental Protection Agency (EPA), Grants Reporting and Tracking System (GRTS).

Beginning in 2011, HeartLands Conservancy and its partners used Clean Water Act Section 319 funding to stabilize streambanks, restore wetlands and reshape part of the creek.