Restoring the Delta
The Mississippi River Delta is disappearing rapidly, but we can restore this national treasure and its hunting and fishing opportunities. However, the science is telling us that we have to get started soon, before it is too late. Here’s how we can get it done:
Reconnect the river to its delta: The Mississippi River’s seasonal flooding created the delta over thousands of years. Large-scale sediment diversions can mimic the river’s natural processes in a controlled fashion and restore existing wetlands while building new land. The proof that this can be done lies in a flood-control channel called the Wax Lake Outlet that has—albeit unintentionally—built a five-mile long delta since its creation in 1942. As many as 200,000 waterfowl have been spotted in the Wax Lake Delta on a single day.
Use sediment to build land: For the coast to survive, every bit of sediment in the river must be used effectively. Every year 22 million cubic yards of sand and mud—the life blood of the wetlands—are dredged to make way for shipping and dumped in deep water off the continental shelf. We need to design effective sediment diversions and strategically re-use some of this dredged material to sustain and build coastal land.
Protect shorelines with oyster reefs: Oyster reefs are not just a great place to catch fish, these living reefs absorb wave action from storms; provide high quality habitat for fish and birds; improve water quality; and cast off old shells that naturally armor the coast and prevent erosion. Additionally, oyster reefs can grow to keep up with sea level rise.
Protect and restore barrier islands: Barrier islands define the outer limits of the estuary and help maintain the transition from fresh water to salt water important for so many species. Barrier islands are the “first line of defense” against storm surge and dampen damaging storm waves before they reach the coast. Louisiana’s barrier islands are eroding rapidly and in some cases this erosion was made worse when the oil spill damaged marsh vegetation on the islands.
Restore a more natural hydrology: When canals are dredged through the wetlands for oil and gas exploration and for navigation, the dredged soil is frequently piled along the sides of the canals in small levees called spoil banks. These banks prevent the normal flow of water and nutrients into and across the marsh, and the canals allow salt water to flow far inland, killing fresher marshes. Removing the spoil banks and refilling unused canals are simple and quick steps to restore the smooth flow of water, prevent further salt water intrusion, and help the marshes to thrive.
Manage the rivers for restoration: The Atchafalaya River, a distributary of the Mississippi River, feeds the largest river-swamp in the country and is building healthy coastal wetlands at its mouth. Right now, the Army Corps of Engineers arbitrarily restricts the Atchafalaya River to 30 percent of the combined flow of the two rivers. Instead, we should manage both rivers based on an ecologically sound plan for sustaining and restoring the coastal wetlands while meeting the needs of the shipping industry.