Hurricane Protection

Algiers Lock
Orleans and Plaquemine's Parish, Louisiana

the challengeThe Bioengineering Group was contracted by the US Army Corps of Engineers, New Orleans District Protection Restoration Office (USACE-PRO) to perform feasibility-level designs for alternative methods of raising the existing hurricane protection to 100-year levels along the east side of the Algiers Canal between Highway 23 and the Algiers Lock. The East and West of Algiers Canal Project provided Standard Project Hurricane (SPH) protection along the Algiers Canal. The Bioengineering Group prepared an Engineering Alternative Report (EAR) that described earthen levee and structural alternatives to raise the existing protection approximately 5.5 feet. Two structural alternative layouts were investigated along the perimeter of an abandoned landfill designated as off limits to construction activity.

the interdisciplinary approachThe Bioengineering Group performed a site reconnaissance to become familiar with the existing structures and levees to identify any potential environmental issues that may affect the analysis and design alternatives. The project area was subdivided into reaches based on geologic and geotechnical data with preliminary alternatives assigned to each reach. The earthen levees and floodwall alternatives were investigated within the reaches to provide recommendations on the most feasible and economical solutions to achieve the 100-year level of protection. Geotechnical analyses were performed using data provided by USACE-PRO. The analyses included slope stability, seepage, pile capacities, settlement analysis, bearing capacity, earth pressures, and external stability as appropriate for each reach and alternative. Structural analysis was performed for T-walls for all reaches and a swing gate at an existing railroad crossing. Additional Bioengineering Group responsibilities included civil layout plates, right-of-way determination, and utility relocation investigations.

the resultsBased on topography, subsurface conditions, civil and structural criteria, real estate and relocations considerations, earthen levee and structural alternatives were recommended for each subdivided reach within the project area. Optimization of the recommended alternatives, including the estimates of probable cost, will be possible during the final design phase. The subsurface conditions in this region present challenging scenarios to provide flood protection to the required 100-year flood elevations. While this project presents viable and constructible alternatives, additional study and analysis will be undertaken to evaluate additional alternatives in an effort to reduce the overall cost, impact to the environment, and reduce the amount of real estate acquisition.