The Problem

The Bonnet Carre Spillway is a flood control structure on the Lower Mississippi River. Located in about 12 miles (19 km) west of New Orleans – it allows floodwaters from the Mississippi River to flow into Lake Pontchartrain and then into the Gulf of Mexico. 

The Spillway is opened when the Mississippi River is so high that it becomes a flood risk downriver, and is becoming increasingly routine as climate change increases rainstorms upriver. For the first time in its history, the spillway was opened in three consecutive years: 2018, 2019, and 2020. Also, last year marked the first time the spillway was opened twice in one calendar year.

But the influx of freshwater and runoff from Midwest farms into the marine environment is blamed for algae blooms that closes beaches along Lake Pontchartrain and the Mississippi coast, kills oysters in Louisiana and Mississippi. Last year’s lengthy openings sparked lawsuits from environmental groups and several cities and counties in Mississippi. 

In addition the sediment rich fresh water, that at one time fed the wetlands of South Louisiana and built the land to what it is today, is diverted via the Spillway into the massive Lake Pontchartrain, which doesn't benefit any wetlands. The leveeing of the Mississippi River has caused the wetlands to die at an alarming rate, the fastest rate in the world. Could the sediment rich fresh water of the Mississippi River be used in a more productive way?

The Solution...?

Fresh water diversion up and down the Mississippi River could solve two problems at once. 

First, during high river stages that call for the Bonnet Carre Spillway to be opened, less water would need to be diverted through it. The environmental effects to the Lake would be greatly reduced. Recent studies have shown that just two medium sized river diversions upriver from the Spillway could cut the amount of water flowing through the Spillway by 60% and reduce the duration of openings by about a third

Second, land-building river sediment and nutrients from the Mississippi River would be diverted into the wetlands where it is so badly needed. The way nature intended it. 

At this time there are two river diversions upriver from the Spillway that the State of Louisiana might build. They are both in the conceptual phase. 

From an environmental standpoint, there few things more important than fresh water diversions to the health of the Louisiana wetlands. We should fight to preserve nature as best as we can, for the future generations. Ending harmful environmental effects at the same time as increasing beneficial ones seems like a win win to me. 

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