The near-capacity reservoirs pose a significant flood risk to 11 south suburban communities, including Blue Island, Calumet City, and South Holland. In Chicago, sewer overflows into the Chicago River have already occurred, and the city's 311 system received nearly 1,000 complaints about basement and street flooding. With soils already saturated and reservoirs nearly full, even moderate rainfall could exacerbate flooding risks. Experts warn that the current infrastructure may not be sufficient to handle the increasing frequency of intense rainfall events linked to climate change.