Lewis Avenue Stormwater Detention Basin Project Passes First Stormwater Test
Recently, the City of North Chicago completed a major phase of the Lewis Avenue Stormwater Detention Basin Project, a critical infrastructure initiative designed to address chronic and severe flooding within the Southwest Pettibone Creek Watershed. For years, the area has been impacted by an aging and undersized storm sewer system.
A key component of the project was the construction of a large stormwater detention basin on a vacant parcel near Lewis Avenue and 20th Street. The basin provides approximately 20.5 acre-feet of stormwater storage capacity.
According to the project engineers, the basin was designed to reduce peak stormwater flows, alleviate pressure on the existing storm sewer system, and significantly mitigate downstream flooding.
The newly constructed basin was put to the test on July 27, 2026, when the city experienced approximately 3.5 inches of rainfall between 10:00 a.m. and 7:00 p.m.
“On that day, the city received approximately 3.5 inches of rainfall from 10:00 a.m. to 7:00 p.m. The detention basin held approximately 5.7 acre-feet of stormwater and slowly released the stormwater over the next 18 hours. Importantly, there were zero reports or evidence of flooding in residents’ yards upstream or downstream of the detention basin. Even though the project is about 80% complete, the detention basin functioned as designed,” explained Bob Miller, Interim Public Works Director.
“This project represents a major step forward in addressing long-standing flooding challenges in our community,” said Leon Rockingham Jr. “For too long, residents in the Southwest Pettibone Creek Watershed have dealt with the impacts of an aging and undersized stormwater system. This investment not only strengthens our infrastructure, but also protects homes, improves public safety, and enhances the quality of life for hundreds of families. We are proud to move this critical initiative forward.”
The $1.7 million project is being funded through the Illinois Department of Commerce and Economic Development.
Additional project improvements include targeted upgrades to the existing storm sewer infrastructure, including the replacement of undersized segments to increase system capacity and performance during 10-year, 50-year, and 100-year storm events.
Once the project is fully completed, it is expected to significantly reduce the frequency and severity of flooding, benefiting approximately 742 residences and more than 900 structures. These improvements will enhance public safety, protect private property, and strengthen the community’s overall infrastructure resilience.
Environmental enhancements will also be incorporated into the project, including a low-flow channel and wetland vegetation designed to improve water quality and support the surrounding watershed.
The Lewis Avenue Stormwater Detention Basin Project represents a significant investment in North Chicago’s infrastructure and a major step toward creating a safer, more resilient community for residents and families throughout the Southwest Pettibone Creek Watershed.