Osborn Engineering designed the Costello/Biddulph basin to maximize the available amount of stormwater detention volume along the existing Dover Ditch, east of Crocker Road and south of Center Ridge Road, within the City of Westlake, Ohio.  The design parameters for this basin expansion were based off of a field run topography and location survey.  An existing concrete weir, that was previously located within Dover Ditch to help alleviate downstream flooding, was removed as a part of this project.  The ultimate detention volume of the new basins was input into a previously-created SWMM hydraulic model to analyze the surface water impacts downstream.  The new basin was designed to include wetland restoration of the riparian corridor and flood plain to improve water quality.  By selecting the appropriate mixture of vegetation for this area, the basin will require minimal maintenance and upkeep while providing lasting improvements to the new habitat. 

Further downstream, Osborn Engineering designed improvements to the eastern bank of Dover Ditch in an area where runoff had been causing localized flooding in a residential area.  By re-establishing the eastern bank to match the height of the western bank, this flooding concern was alleviated.  Additionally, the creation of the Costello/Biddulph basin lowered the water surface elevation within Dover Ditch, providing an additional factor of safety for the existing residents.