Main Street and Buena Vista Detention Basin Project

Over the last few years there have been a few large rainfall events on the Main Street drainage basin that have caused significant runoff events and flooding along Main Street. The two most recent flooding events occurred on July 13, 2018 and August 11, 2018.

Washington City hired Bowen Collins & Associates (BC&A) to analyze the existing storm drainage system within the Main Street drainage basin and develop recommendations for infrastructure improvements to mitigate this flooding along Main Street. Preliminary flood mitigation alternatives were presented to the Washington City Council in a work meeting on August 21, 2018.

At the meeting the City Council requested the BC&A evaluate the following three flood mitigation alternatives further:

• Alternative 1 – Construct new detention basins at Main Street and Buena Vista Blvd
  
• Alternative 2 – Construct road and storm drain improvements along Main Street
  
• Alternative 3 – Construct a new flood channel from the intersection of Main Street and Buena Vista Blvd to Mill Creek
  

Based on our analysis and preliminary designs BC&A recommends the City prioritize moving forward with the following alternatives:

• Alternative 1 – Construction of Debris Basins near Main Street and Buena Vista Blvd to prevent major flooding events both north and south of I-15.  Main Street Basin first phase will consist of a basin 2.13 acres basin and 11.3 Ac-Ft capacity. Phase 2  will increase the size to 5.62 acres and 29.7 Ac-Ft capacity and is anticipated to be constructed in the summer of 2020 Buena Vista Basin will consist of 3.07 acre basin and 9.4 Ac-Ft capacity, Both Basins are currently under construction.

• Alternative 2 – Reconstruction of Main Street to prevent local storm event flooding south of I-15. ( The Main Street project can be found on the Main Street Flood Control Project Page)

These two alternatives will provide the safest, most robust solutions to mitigate flooding along

Main Street.

First phase of the projects complete. Second phase will enlarge the basins for a larger holding capacity. Second phase will start when funding from the NRCS is released anticipating fall of 2020

Main Street

Buena Vista