Summit was the prime consultant for the culvert replacement on Odyssey Drive over Northeast Creek North Prong in Durham, North Carolina. The existing crossing consisted of two projecting aluminum pipe arches that had begun to deteriorate; the City of Durham desired to replace the crossing with a concrete structure.
Northeast Creek North Prong is a FEMA-regulated stream contained in a detailed study. Due to time and budget constraints, the City requested the project qualify for a No-Impact. Summit’s hydraulic design team developed several alternatives for the culvert replacement and prepared an alternative analysis comparing the cost, serviceability, and construction time of each alternative.
Based on our recommendations, the City decided to pursue the cast-in-place reinforced concrete box culvert alternative (RCBC). As a No-Impact was critical to the project, Summit’s roadway and hydraulic design teams frequently collaborated to ensure changes to the roadway grade would not cause any increases to the water surface elevations.
The proposed culvert replacement was a double barrel 9’x7′ RCBC, which required 375 LF of roadway design. A low and high-flow barrel was designed to better match the upstream and downstream channels.
This proposed design qualified for a No-Impact. Summit’s hydraulic design team prepared the No-Impact package, including the HEC-RAS modeling, Culvert Survey Report, project narrative, water surface elevation tables, and work map.
In addition to the culvert hydraulic design, Summit designed a replacement for the existing closed system drainage system and the erosion control plans, including the culvert phasing. Replacing the existing pipe arches with an RCBC conflicted with the existing waterline. Summit designed the waterline relocation plans to maintain the required vertical separation.