This project was a culmination of over 20 years of studies and storm water improvement projects to mitigate the flooding of southeast Missoula, Montana.
This project provides an infiltration, retention and discharge drainage system of 60-inch diameter pipe to convey and store the 100-year flood flow through southeast Missoula. It uses a combination of open-channel pipe flow and pressure flow with pressure release discharge. With the exception of major storm events, the system’s retention discharge basin functions as a city park.
WGM Group worked with the City of Missoula and Federal Emergency Management Agency (FEMA) to obtain a Conditional Letter of Map Revision (CLOMR) to remove a substantial portion of the city from the 100-year flood plain. There have only been a few CLOMRs of this magnitude approved in the State of Montana.
