The Collapsing Delta
Over the past eighty years, the Mississippi River Delta has lost an area of wetlands almost as large as the state of Delaware.
Many factors have led to the delta’s collapse, but none as much as the series of levees that were built following the Great Flood of 1927. The lower section of the river was straight-jacketed behind earthen dams as part of a national program to prevent flooding on the Mississippi River from Missouri to the Gulf. These levees protect low-lying communities from seasonal flooding, but they deny the delta’s wetlands the freshwater, sediments and nutrients they need.
Additionally, a vast network of shipping routes such as the Mississippi River Gulf Outlet, the Houma Navigational Canal, the Calcasieu Ship Channel and the Freshwater Bayou and hundreds of smaller oil and gas navigation route were carved into the wetlands. These canals allow saltwater to penetrate deep into the wetlands, killing marsh vegetation, eroding the banks and disrupting the salinity balance important for species at the heart of the Gulf’s food web—such as shrimp, blue crabs and oysters.
The Mississippi River Delta continues to disappear at an astonishing rate: a football field of wetlands vanishes into open water almost every hour. If we don’t act soon, the delta as we know it will be gone forever.
There are solutions. The Mississippi River’s annual flooding created the delta over thousands of years. We can restore the wetlands by strategically reintroducing freshwater and sediment, mimicking the river’s natural processes.