Alpha & Omega Group conducted a hydraulic analysis for a multiple-barrel culvert, W-5107, located at the intersection of US 70 and Davis Mill Road in Johnston County. 

The project included developing culvert survey reports for replacing a triple 60-inch circular pipe culvert under Davis Mill Road, constructing a new culvert for a proposed exit ramp and service road, and evaluating the impacts to the existing double-box culvert under US 70. The new structures were designed to be double-box culverts with one structure buried 12 inches and the second to include a “floodplain bench” as required by the North Carolina Department of Transportation. Because of nearby residents, additional sensitivity was given to the culvert design. Though not required, the culverts were designed to carry the 100-year storm event without producing an increase in water surface to minimize the impacts to nearby residents.