Barataria Land Bridge and Large Scale Marsh Creation
Marshes and wetlands can be created through the placement of sediment via dredging. While this strategy is highly successful in creating marsh in a short period of time, dredging and placement must be repeated at regular intervals, otherwise, subsidence, sea level rise, and channelization will continue to cause land loss and degrade created wetlands and marsh. Strategically creating land through dredging allows us to quickly rebuild key areas of the coast to provide immediate benefits. Using this method in conjunction with other strategies, such as sediment diversions, can increase the lifespan and sustainability of land creation projects.
Historically, miles of contiguous land connected the area south of New Orleans between the Mississippi River and Bayou Lafourche, and there was limited hydrologic connectivity between the fresher upper marshes and the saltier lower marshes. Due to canals, subsidence, levees, and erosion, most of that area has been lost to open water. To rebuild the historic land bridge, a X-mile pipeline has been constructed to move sediment from the Mississippi River for rebuilding. The construction of the Mississippi River Long Distance Sediment Pipeline was completed in 2016 to
transport sediment from the river to various locations within the Barataria Basin. CPRA led the completion of this project. It was funded by the Coastal Impact Assistance Program and completed for $66.3 million. The sediment from this pipeline has already begun building marsh and ridges, including the Bayou Dupont Ridge and Marsh Creation Project. Just as marsh is built where there was previously marsh, ridges are restored along the edges of old distributaries. These were areas of natural high ground that could support native tree species, such as live oak. The goal in all marsh and ridge creation is to emulate the natural environment that existed prior to the accelerated rates of land loss.
Bayou Dupont before sediment pumping, 2012. Source: Google Earth
Projects that compose the Barataria Large Scale Project are in various stages of completion. The 2017 Coastal Master Plan includes two major projects for marsh creation in Barataria Bay. These two projects combined will create approximately 20,300 acres of new wetland and marsh habitat. The projected costs for these two projects is a little over $1.4 billion dollars. Planning, engineering and design for each of these marsh creation projects is expected to take three years with construction estimated to take between 5-7 years. The Component E Marsh Creation project was recommended for further evaluation in the Louisiana Trustee Implementation Group Strategic Restoration Plan and Environmental Assessment #3 in early 2018, setting the stage for this project to be funded using Natural Resource Damage Assessment funds in the future, following an environmental review.