Duchesne & Hawthorn Culvert Replacements
Impacted Ward: 7
Design Consultant: George Butler Associates (GBA)
The existing culverts under Hawthorn Ave and Duchesne Drive on Boschert Creek do not adequately convey existing storm water flows and are the cause of frequent flooding of properties upstream of the culverts. The City of St. Charles Comprehensive Stormwater Masterplan identified the flooding issues, and anticipated replacing the existing structures with new Reinforced Concrete Box (RCB) Culverts. The design will include HEC-RAS modeling to determine the actual size and final layout of the culverts for construction. Following completion of construction, the City intends to submit a Letter of Map Revision (LOMR) to FEMA to remove adjacent structures from the floodplain.
Boschert Creek between Hawthorn Ave and Pine Street was identified in the Comprehensive Stormwater Masterplan as widening with bank failures in several locations. Repairs have been attempted with dumped rock. Though not identified in the masterplan, the creek banks between the culverts will also be evaluated to determine whether additional stabilization is needed. The project will include stabilization of the creek banks along this reach by use of grade controls, revetment, native vegetation, etc.
- Crews performed soil borings and survey beginning in August 2020.
- Designer submitted Alternatives Analysis report in September 2020 for replacing the culverts.
- Preliminary plans approved in January 2021. Easement acquisitions are expected to begin in the next few weeks.