Robbins Flood Control Project
Client: Metropolitan Water Reclamation District of Greater Chicago
Location: Village of Robbins, Illinois
The Village of Robbins is a historically important south suburb of Chicago. Located near the mouth of Midlothian Creek at the downstream end of the watershed tributary to the Little Cal River, the Village has experienced increasing flood events in terms of both intensity and frequency. The Village was identified as a high priority through the MWRD’s Detailed Watershed Plan for the Little Cal River and Donohue was selected to evaluate potential options. Up to 140 acres of the Village were at risk of flooding. In addition, a major state road, Kedzie Avenue, is forced to shut down at least once a year due to water on the pavement.
With a team of subconsultants including 2IM Group, Living Habitats, SOM, Accurate Group, and O’Brien and Associates, Donohue evaluated a range of potential solutions. The Village preferred to avoid more traditional dry-bottom, isolated detention. In addition, the Village has suffered through an extended economic downturn. Recognizing a unique opportunity, the District, supported by the Donohue team, engaged a broad range of regional governmental and non-governmental agencies to create a solution that integrates the flood control project into the Village’s long-term plans and goals for redevelopment and capacity building. Agencies engaged included the Chicago Metropolitan Agency for Planning (CMAP), South Suburban Mayors and Managers Association (SSMMA), Regional Transit Authority (RTA), Cook County Housing Authority, Cook County Department of Transportation, and many others. Working closely with the Village, the District and the Donohue team developed a flood control plan that integrated flood control improvements with a community open space/park, a future transit oriented development (TOD) and redevelopment of a former industrial area for job creation.
Technically, through more detailed HEC-RAS modeling, the team quickly identified that the extent of the problem was greater than originally identified in the DWP, but consistent with the Village’s reported flooding frequency. A confluence of increasing flows, restricted existing conveyance, and topography limited potential options. The final alternative includes detention, diversion to the Cal-Sag Channel, berming, streambank improvements, and green infrastructure for local drainage mitigation. The proposed wetland park will provide approximately 8 ac-ft of detention storage for the 100-yr event, and the Diversion Channel will convey 383 cfs during the 100-yr event, helping to reduce high flows in downstream Midlothian Creek. The project required utility relocation, new storm sewer for roadway drainage, and three 54-inch conduits micro tunneled beneath an existing roadway. All these improvements were integrated into a new naturalized wetland park with space to allow for future community amenities including playground, natural amphitheater, athletic fields, and event facility. Amenities included in the original construction designed by the Donohue team include walking trails, vehicle access drives, and a kayak launch at the connection of the diversion channel to the Cal-Sag Channel.
The project will be constructed in multiple phases to facilitate a faster construction schedule and to align with available grant funding. Close coordination with permitting agencies also factors into the phasing approach. Following completion of the project, a Letter of Map Revision will be produced to remove almost 100 structures from flood hazard areas.