Modification to John H. Overton Lock and Dam

The Red River Waterway Project, Mississippi River to Shreveport, Louisiana, will consist of a navigation channel 9 feet (2.7m) deep by 200 feet (61.0m) wide, 5 locks and dams providing a total lift of 141 feet (43.0m) and a number of channel realignments and revetments for a length of 236 miles (379.8km). Immediately after Lock and Dam No.1 was put into operation in the fall of 1984, sedimentation occurred in the vicinity of the lower miter gates. This sedimentation hindered the operation of these gates. Since the downstream approach of the next upstream lock and dam, John H. Overton Lock and Dam, was based on similar model study results as Lock and Dam No. 1, it was decided that modifications to the design should be made. This was complicated by the fact that John H. Overton Lock and Dam was under construction. The modification had to provide safe navigation conditions. Additionally, the modification had to satisfy geotechnical and structural criteria as well as contractual limitations. This paper discusses the design process which included both physical and numerical model studies and how this process considered the criteria mentioned above for the contract modification. It also discusses a modification to the downstream channel that was implemented in response to the damage that occurred.