Restore the Mississippi River Coalition position on freshwater diversions and dolphin deaths

Restore the Mississippi River Coalition is committed to the long-term health of the Louisiana coast and wildlife. Recent freshwater releases by the USACE from the Mississippi River have altered salinities and concern has arisen on the wildlife

Our groups are concerned about what is happening to dolphins across the Gulf and urge those agencies charged with monitoring dolphin populations to provide thorough scientific analyses detailing recent occurrences.Dolphin mortality can occur for a wide variety of reasons and determining the cause of mortality will take time. Unfortunately, mortality events for marine mammals are not that uncommon. Over the last 30 years, 19 such events in the Gulf of Mexico have been categorized as “unusual mortality events.”

If you have specific questions or need to report a dolphin stranding, please contact members of NOAA’s Marine Mammal Stranding Network.

In the meantime, we remain focused on the long-term future of the Mississippi River Delta and its people, wildlife and jobs — and that includes both the long-term health of dolphins and the long-term restoration and maintenance of Louisiana’s coastal habitat. Louisiana’s land loss crisis has upended the natural order of our estuaries and coast, threatening all wildlife and people. Unless we act, we risk losing it all. If the collapse of coastal marshes in Louisiana continues at its current pace, the future of not only dolphins but all wildlife and the 2 million people that depend on Louisiana’s coast is grim.

The opening of the Bonnet Carre Spillway is an extreme, emergency event, a response to floods made necessary because of dire threats to people and property living in parishes along the lower river. The sediment diversions proposed in the Louisiana Coastal Master Plan are operated differently than the spillway. Unlike the spillway, which is a massive 250,000 cfs flood control structure, projects like the Mid-Barataria Sediment Diversion and Mid-Breton Sediment Diversion are smaller, strategically located and will be operated in a controlled and adaptable manner to deliver land-building sediment into marshes that would otherwise be wiped off the map. These projects are vital to the long-term health of the entire Mississippi River Delta ecosystem.

The Bonnet Carre Spillway is a legacy of an outdated management system designed after the great flood of 1927. While we remain dependent upon it, its opening is sudden, requiring the receiving basins to quickly adapt to rapidly changing conditions. Its opening used to be a rare event, but no more. After centuries of short-sighted engineering aimed at taming our rivers, many of these efforts have backfired and are now increasing flood threats. Changing weather is only further compounding the issue and stressing our river management and flood control systems.

As climate scientists predicted, extreme rainfall and flooding events are becoming more common, and the last 7 months have seen the largest combined flow of water down the Mississippi River in recorded history, with more to come. This winter has been the wettest on record for most of the river’s drainage basin. Conditions have changed since the spillway was designed and constructed, and we can expect more high flows from the Mississippi River and other rivers in the future.

As the Army Corps of Engineers prepares to open the Bonnet Carre Spillway for an unprecedented second time in the same year, we need to re-think the overall management of our rivers and develop solutions to confront future challenges that address both sea level rise and this increased precipitation within our watersheds.

In some areas, that means doing a better job of managing runoff in our forests and on our farms throughout the basin; giving the river more room between the levees in the Mississippi Valley; and opposing schemes to drain more wetlands that hold and absorb floodwater.

In Louisiana, that means using all the tools in the toolbox to manage the Mississippi’s water and sediment as it heads toward the Gulf, including not only opening the Bonnet Carre spillway when nearby communities are at risk, but also constructing controlled sediment diversions.

These are two very different tools, operated in different ways — one is for flood protection and one is for coastal restoration.

In addition to helping us better manage the overall river system, sediment diversions will help us restore vital habitat and maintain wetlands that help buffer storm surge from the Gulf. They will help us address threats posed to our communities and wildlife by saltwater intrusion, sea level rise and storm surge.

As these projects are constructed and operated, monitoring of dolphin populations and other wildlife and adaptive management will be crucial. We fully support the use of robust monitoring to understand how diversions are building land, influencing salinities, and affecting a wide array of species, including dolphins.

See Restore position statement . . .