Canal Reclamation at Barataria Preserve Environmental Assessment Jean Lafitte National Historical Park and Preserve

National Park Service; Clark, Carol

The purpose of the proposed project is to restore functions, resources, and values related to hydrology in the Barataria Preserve (Preserve) unit of the Jean Lafitte National Historical Park and Preserve that are affected by non-historic canals, spoilbanks, and dikes, and to increase the resiliency of Preserve ecosystems to subsidence, sea level rise, and storm events. A portion of the funding for this project may come from funds associated with the American Recovery and Reinvestment Act of 2009. Oil and gas exploration, development, and transportation, along with residential development projects that never fully materialized, have scarred the landscape of the Preserve with man-made non-historic canals and earthen structures. More than 590 acres of the Preserve are directly affected by these non-historic canals, spoilbanks, and dikes, and more than 20 linear miles of non-historic canals throughout the Preserve have been identified for reclamation. Currently, non-historic canals and spoilbanks in the Preserve contribute to increased rates of land loss and to the spread of invasive vegetation species. Canals and their associated spoilbanks alter hydrology and have both direct and indirect roles in Louisiana’s land loss problem. Directly, canals have turned marsh into open water, and spoilbanks have replaced marsh with an upland environment. Indirectly, spoilbanks restrict water flow above and below the marsh surface and can cause both increased flooding and drying of the marsh behind the spoilbanks. This hydrologic alteration can limit sediment deposition, movement of nutrients and aquatic wildlife, stress marsh vegetation, increase subsidence, and lead to marsh deterioration. Other impacts include amplification of tidal volumes and increased saltwater intrusion into freshwater marsh. In addition, the vegetated communities in wetlands adjacent to canal dredging sites have changed, and the canals and spoilbanks are now colonized by invasive exotic species. Wetlands benefit coastal communities by providing protection from flooding, helping to maintain water quality, and providing habitat for fish and wildlife, including estuarine organisms, wintering waterfowl, and neotropical migrant birds. The loss of these wetland functions due to the construction of canals continues to adversely impact the Preserve.