Louisiana's Vanishing Coast: Flood Control Created Crisis

Over the past century, extensive levees built along the Mississippi River successfully shielded cities and farmland from major floods. However, this flood control system has led to significant ecological damage, contributing to the loss of about 4,900 square kilometers of Louisiana's coastal land since the 1930s.

Historically, annual spring floods would deposit millions of tonnes of sediment across the delta, balancing land subsidence and protecting the coast. The U.S. Army Corps of Engineers' levee system prevented these natural sediment deposits, sending the river's load into the Gulf of Mexico instead. This lack of replenishment, coupled with rising sea levels and oil industry activities, caused coastal marshlands to sink and saltwater intrusion to kill vegetation.

To combat this erosion, agencies are now undertaking marsh creation projects by redistributing river sediment. A notable example is the Upper Barataria Marsh Creation Project, where approximately 8.4 million cubic yards of sediment were pumped into degraded marsh areas. This initiative successfully created 1,259 acres of new land and shallow-water habitats, including wetlands and tidal ponds.

Restoration efforts are showing promising signs of ecological recovery. Native species like shrimp, crabs, and fish have been observed in the new waterways, and marsh plants have begun to grow. The project includes a 20-year adaptive management plan to monitor its success and make adjustments as needed. While this project addresses a fraction of the lost land, it serves as a crucial model for rebuilding deltas across southern Louisiana.