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Louisiana Coastal Area, Amite River Diversion Canal Modification

Client: Coastal Protection and Restoration Authority

Areas of Expertise: Water Resources

The Louisiana Coastal Area (LCA) Amite River Diversion Canal (ARDC) Modification project, which was authorized by the Water Resources Development Act of 2007, is part of the 2005 LCA Master Plan aimed at restoring coastal Louisiana. The goal of this project was to restore approximately 19,000 acres of degraded cypress-tupelo swamp found along the ARDC in both Ascension and Livingston Parishes. The primary recommendations developed from this project focused on restoring hydrologic connectivity and reducing impoundment for the freshwater swamp habitat adjacent to the ARDC. The recommended plan involved vegetative plantings, the construction of gaps in the dredged material berms found along the ARDC, and the connection of these gaps and the interior swamp through the construction of bifurcated conveyance channels. Benefits of the recommended plan include the creation of additional freshwater swamp habitat by restoring a more natural hydrologic regime within the study area and measures aimed at combating the effects of relative sea level rise.

The project involved the combined efforts of the United States Army Corps of Engineers and the State of Louisiana, along with coordination between numerous state and federal agencies and all required public meetings.

  • Deliverables included a Feasibility Report and Supplemental Environmental Impact Statement.
  • Applicable permits and environmental review included a Biological Assessment, Coastal Zone Consistency Determination, 404(b)(1) permit application, and USFWS Coordination Act Report.
  • Technical efforts included the development of a hydraulic and hydrology model, consideration of sea level rise and subsidence, the modeling of benefits through the Wetland Value Assessment model, cost effectiveness and incremental cost analysis determinations for all proposed actions, and cost estimations, including the development of a risk-based cost contingency.

It was estimated that the recommended plan would provide 679 Average Annual Habitat Units over approximately 3,000 acres and cost approximately $8.5 Million.

Contract Information:

DNR No. 2503-07-13