Overview
Horner & Shifrin was contracted by Ameren Missouri to provide floodplain permitting assistance with St. Louis County for aging tower replacement in unincorporated portions of their jurisdiction. The utility company is replacing aging infrastructure with more modern mono-poles along various waterways. Ameren required assistance providing a hydraulic analysis of Gravois Creek and a no-rise certification for their proposed work within the floodway to prove a no-rise condition. While coordinating the project with Ameren, H&S identified portions of the project that are also within the River Des Peres floodway, which is within St. Louis City jurisdictional boundaries. H&S staff met with the City’s Floodplain Administrator and coordinated with the County’s Floodplain Administrator to determine requirements and application procedures.
Flood analysis for both waterways includes acquiring the existing HEC-2 river models and importing and developing HEC-RAS models for the duplicate effective, corrected effective, existing, and proposed conditions. Floodplain analysis reports, Floodplain Development Permit Applications, and No-Rise Certificates will be provided upon analysis completion to both the City of St. Louis and Unincorporated St. Louis County.
