Project Name: St. Vrain Creek, Longmont, Colorado Flood Risk Management Study
Location: Longmont, Colorado
Authority: Section 205 of the Flood Control Act of 1948, as amended
Sponsor: City of Longmont
Current Phase: Feasibility
The U.S. Army Corps of Engineers (Omaha District) is partnering with the city of Longmont (non-federal sponsor) on a study to evaluate possible flood risk management solutions along the St. Vrain Creek, a tributary of the South Platte River in Longmont, Colorado.
The principal problem this study aims to address is the high existing risk of flooding and flash flooding of residential, commercial, and public infrastructure. In September 2013, the St. Vrain Creek experienced catastrophic flooding. Sections of Colorado Highway 7, U.S. Highway 36, local roads and public, residential and commercial properties along the St. Vrain Corridor were destroyed. One of the hardest hit communities during this flood event was Longmont. The St. Vrain Creek within the city of Longmont exists within a wide-bottom valley which is geologically unconfined. This area is highly urbanized with residential, commercial and industrial land uses. Development has restricted or influencted the alignment of St. Vrain Creek.
The purpose of the St. Vrain Creek feasibility study is to identify the potential for developing flood risk management solutions, which could be structural and/or nonstructural, that are beneficial to the public, economically viable, and environmentally acceptable.
Project Update: The Final Feasibility Report and Environmental Assessment (EA) for the St. Vrain Creek, Longmont, Colorado Flood Risk Management Study was released in October 2020. The plan includes a levee on the south side of the Izaak Walton Pond Nature Area; channel widening and benching to contain the 1% annual chance exceedance event; replacement of the Boston Avenue Bridge; and a grade control structure downstream of Sunset Street Bridge. The project will now move into design phase.