Rock Island District Public Notices

City of Des Moines (CEMVR-RD-2021-1434)

Rock Island District
Published Dec. 7, 2021
Expiration date: 1/5/2022

The Applicant proposes to construct a small flood control facility to reduce the frequency and duration of flooding events for the local area by replacing the existing infrastructure and limiting peak flow rates by providing regional flood control at this location. Specifically, this project will include replacing the existing wood structure culverts and storm sewer system with RCP and concrete box culverts. The outfall of this structure will discharge into 8' flat bottom channel with 4:1 side slope. This site will consist of construction of a detention basin constructed by enlarging and dredging adjacent to an existing V-bottom channel. It will aide in the reduction of bank erosion and channel stability and to provide additional storage during large rainfall events. Bank armoring will be implemented through the cut-banks of the channel improvements to prevent erosion and improve water quality. This will include Class "D" Rip-Rap and geo-grid material. The proposed detention cell will have an outlet structure that provides a pre-development release rates and will aide in the reduction of the overall peak flow rates. The detention basin will be seeded with wetland vegetation.