Unprecedented Repeat Opening of Bonnet Carré Spillway Underscores Need to Manage Mississippi River Differently

Conservation Groups Emphasize Currently Untapped Coastal Restoration Potential of River

New Orleans, LA – On Wednesday, February 27, the U.S. Army Corps of Engineers (Corps) plans to open the Bonnet Carré Spillway in St. Charles Parish, alleviating pressure on downriver levees and preventing flooding. An unprecedented event, this will mark the third time the spillway is opened in the last four years – the first time in history to be opened in back-to-back years. It is the result of the wettest winter in the Mississippi Valley in the last 124 years. The 7,600-acre Bonnet Carré Spillway is located upriver of New Orleans. When opened, this structure is designed to shunt up to 250,000 cubic feet per second of sediment-laden water from the river into Lake Pontchartrain, to reduce pressure on the river levees by keeping water flow below 1.25 million cubic feet per second.

Restore the Mississippi River Delta – a coalition of national and local conservation organizations committed to coastal Louisiana restoration including Environmental Defense Fund, the National Wildlife Federation, National Audubon Society, Coalition to Restore Coastal Louisiana and Lake Pontchartrain Basin Foundation – issued the following statement in response:

“Another year brings another opening of the Bonnet Carré Spillway, and sediment and fresh water that should be directed into Louisiana’s vanishing wetlands will go into Lake Pontchartrain instead. While the Corps has effectively managed the Mississippi River and Tributaries Project for flood protection and navigation, it must prioritize coastal restoration in managing our rivers as well.

“Louisiana is losing land and we’re losing time, and too much of the nearly 100-million tons of sediment passing through our state each year continues to be wasted. Opening of the Bonnet Carré Spillway alone results in roughly 9 million cubic yards of sediment lost into the spillway and Lake Pontchartrain. The river’s sediment is our best resource for rebuilding and maintaining land across our coast, and too much of it continues to flow past our dying wetlands into the deep waters of the Gulf of Mexico or be dumped into Lake Pontchartrain.

“This latest opening is unprecedented not just in terms of frequency, but also because it is due to the wettest winter in the Mississippi Valley in 124 years. If climate change continues to cause increases in rainfall, pressure on our levees will only increase, as will the need to open our spillways with increasing frequency. Projects like the Mid-Barataria and Mid-Breton Sediment Diversions, and proposed upriver diversions, would help reduce pressure on levees, while capturing sediment to maintain and build wetlands – further reducing the risk of flooding for our communities. These projects will manage the river for restoration in conjunction with the levees and spillways that provide flood protection – a win-win for the people of Louisiana and the coast that allows us to call this place home.”

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