The City of West Plains has been awarded a $764,212 Community Development Block Grant (CDBG) for the construction of a storm water detention basin at the North Fork of Howell Creek.
As planned, the basin is meant to reduce peak flow volumes to limit the impact that significant storm events have on residents and businesses within the City of West Plains, such as the Spring, 2017 flood. This is based on a Storm Water Evaluation and Management Planning Study that included a hydrologic and hydraulic model of the primary drainage system in the city.
That study indicated the addition of four detention basins will likely “resolve numerous identified problem areas as well as significantly reduce the frequency of flooding to existing infrastructure,” said storm water specialist Trent Courtney of the City’s Planning Department.
Other basins have been proposed in Burton Branch, Galloway Creek and South Fork of Howell Creek.
The new basin will be 100 percent funded by the CDBG and located in the North Fork of Howell Creek drainage area where it meets the city limits. The basin will consist of approximately 21,000 cubic yard of fill material to construct an earthen berm to retain storm water during peak storm events, an outlet structure to control flows, and an energy dissipation structure to limit the impacts of erosion.
The earthen berm will have a maximum height of 18 feet from the flowline of the outlet structure to the top of the berm. The overall length of the berm is anticipated to be 930 feet, and the 100-year water surface elevation of the retained water will be 1,028.14 feet. That includes an overall detained water surface area of approximately 32 acres.
Courtney said the new basin is expected to reduce peak flow rates by 48% and would remove 16 acres of land from the floodplain within the first mile of the North Fork.
“Based on the results of the engineering report, it is anticipated that numerous residential and commercial structures will see a reduction or elimination in potential future damages due to flooding,” said Courtney. “It is also anticipated that due to the basin, existing storm water structures beneath roadways will be capable of handling heavier storms due to the reduction of peak flows. This will increase the ability of emergency vehicles to traverse roadways during flooding events.”
Courtney indicated the City will be responsible for land acquisition, inspections, construction surveying and grant management.