St. Charles is pushing ahead on a plan to pull nearly 20 properties out of harm's way along Seventh Avenue Creek, with the city council backing a $232,470 design contract earlier this month to replace undersized stormwater culverts along 10th and 11th avenues. The work is expected to remove five residences and three businesses from the flood danger zone entirely, while lessening flood risk for 11 additional properties nearby.
The creek carries stormwater from Kirk Road to the Fox River and has a long history of flooding, as reported by Shaw Local. That history traces back to a severe 2008 flood that prompted FEMA to revise its Flood Insurance Study for the creek, a revision that pushed 100-year flood flow estimates up by roughly 250% and raised base flood elevations by nearly 3 feet, according to HR Green. That single storm effectively rewrote the city's flood maps overnight, dropping dozens of additional properties into high-risk zones they hadn't occupied before.
A Multi-Year Master Plan Years in the Making
The city answered with its Seventh Avenue Creek Master Plan, finalized in 2017, a multi-phase framework meant to clear every structure out of the creek's 100-year floodplain and buy out 13 flood-prone homes for demolition, per the City of St. Charles. Before any of that construction began, FEMA's map revisions had flagged 118 parcels along the creek's two-mile stretch as flood-impacted — 55 residential structures and 13 commercial ones — and the full plan is designed to eventually bring that commercial number down to zero.
Phase 1 of the project, running between Washington Avenue and S. 10th Avenue, wrapped up in 2021 and included 2,800 linear feet of stream bank stabilization, 12 new meanders, 12 grade control structures, culvert upsizing under three avenues, and 4.6 acres of native riparian planting, HR Green's project records show. That initial phase cost $3.58 million, with grant funding totaling $2,622,967, according to HR Green.
Why the Downstream Fix Came First
Before the city could upsize culverts further upstream along 10th and 11th avenues, it needed room downstream for all that extra water to actually go. St. Charles replaced the culverts under Route 25, also known as Riverside Avenue, with much larger infrastructure in May 2025, expanding drainage capacity at the creek's outlet into the Fox River, the city confirmed. HR Green worked on that Route 25 culvert project and helped secure more than $640,000 in Illinois Department of Transportation funding to make it happen.
Chris Gottlieb, St. Charles' public works manager of the engineering division, said HR Green brings knowledge of the watershed and its drainage patterns. The existing culverts along 10th and 11th avenues are simply too undersized to handle large rainfall events, and the new infrastructure is meant to let water flow directly into the Fox River instead of spilling out across city streets and yards.
Regulatory Hurdles and What Comes Next
Engineering changes of this scale don't happen without federal and state sign-off. The work has required a formal Conditional Letter of Map Revision from FEMA, along with permits from the U.S. Army Corps of Engineers, the Illinois DNR Office of Water Resources, and the Illinois EPA, according to HR Green. Full implementation of the master plan has also depended on extensive public outreach and property acquisitions to secure stream easements and buy out the most vulnerable homes.
The regional engineering community has taken notice: the American Public Works Association's Fox Valley Branch named the Seventh Avenue Creek Flood Reduction and Stream Restoration Project its Public Works Project of the Year in 2022, one of several APWA honors the city has collected for major infrastructure work.
The newly backed design contract with HR Green still requires a final city council vote before moving forward. If approved, design work on the 10th and 11th avenue culverts is expected to begin this fiscal year, with construction slated for the following fiscal year.
