TSS 69 North Chicago is a substation located within the Federal Emergency Management Agency’s (FEMA) designated 100-year floodplain and floodway of the Skokie River in North Chicago, Illinois. The location of the substation posed significant risk to it due to the river’s history of flooding. The intent of this project was to mitigate the flood risk to the substation and enable its future expansion in such a high-risk area.

Primera Engineers mitigated the risk to the substation, which helped to increase the resiliency of the power grid and to the community, by designing a floodwall to surround and protect it. The design work for this project was extensive and complex due to the regulatory constraints in place, which fell under various agencies’ jurisdiction. Primera not only worked with local, state and federal agencies to obtain all necessary permits, but to also meet floodway criteria and to incorporate a joint flood mitigation project into the proposed modeling of the floodwall.

This project officially removed the 100-year floodplain and floodway designation from the existing substation and future expansion area. These steps also provided the added benefit of removing the difficult regulatory challenges posed by the floodway for future expansion.