A quick guide to Louisiana’s largest coastal project
The Mid-Barataria Sediment Diversion Project
NEW ORLEANS (WVUE) - Louisiana’s controversial proposed $2 billion plan to divert a portion of the Mississippi River into the marsh south of Belle Chasse can tough to digest. Here is a quick guide to the largest-ever coastal restoration project.
Over the last roughly 90 years, geologists tell us Louisiana has lost 2,000 square miles of its coastline. The U.S. Geological Survey estimates, in the average year, roughly a football field worth of land disappears over the course of 90 minutes. The state could lose another 274,000 aces of land over the next 50 years unless something is done. The rate of land loss has fallen since its peak in the 1970s.
What’s causing the land loss:
While many factors contribute to this loss, including natural forces, man has altered the landscape and hastened the decline in many areas. Louisiana is sinking. This subsidence occurs naturally, but the Mississippi River once offset the effects as it deposited sediment during annual spring flooding. Oil field canals introduced salt water into fresh areas and interrupted the natural tidal flow. As islands and remnant marsh become more isolated, hurricanes and everyday tides erode these areas.
The Louisiana Coastal Protection and Restoration Authority (CPRA) proposes, as part of the state’s Coastal Master Plan, to reconnect the river with the marsh. The Mid-Barataria Sediment Diversion Project, near Myrtle Grove on the Plaquemines Parish west bank, would feed river water and sediment into Barataria Bay. The diversion would channel up to 75,000 cubic feet of water per second into the bay and operate for an average of 177 days a year. The $2 billion dollars cost is funded through settlement money from the 2010 BP oil spill in the Gulf of Mexico.
Common Arguments from supporters:
- Sediment diversions will re-establish natural processes that originally created the delta and maintain wetlands lost over the past century.
- The MBSD is forecast to create 28 acres of land in the first 30 years of the project and sustain other marsh in Barataria Bay. Some land is forecast to be lost in subsequent years as seas rise due to climate change. However, the river can provide something of a hedge against rising seas, as land builds up over the years.
- In the absence of action, remaining marshes, islands and ridges in Barataria Bay will continue to collapse.
- Smaller fresh water diversions, which were never designed to build land, have resulted in the creation new marsh.
- Designers have used the most sophisticated computer and physical modeling to maximize the delivery of sediment.
Common Arguments from opponents:
- The project will introduce massive amounts of fresh water into the bay, causing serious damage to fisheries, such as shrimp and oysters.
- The introduction of fresh water will kill hundreds of dolphins in the first years of operation and push the dolphins from most parts of the bay.
- Land building can be accomplished more quickly through dredging projects that deliver sediment by pipe.
Congress granted the diversion a waiver from the Marine Mammal Protection Act, which would normally have barred the project because of the harm to dolphins. However, federal law still requires the impact to marine mammals to be minimized.
Mitigation: The Louisiana Trustees Implementation group has outlined $300 million in various mitigation efforts. Those include dolphin rescue efforts, the seeding of new oyster reefs, and refrigeration improvements for shrimpers forced to travel farther from the dock to find their catch. CPRA said recently it would provide more detailed plans soon.
What happens next: The U.S. Army Corps of Engineers, which issued a draft Environmental Impact Statement recently, expect to make a final decision next year. Opponents have vowed to take the issue to court even if the Corps grants a permit.
“We have to take the long view. We have to think of our children and grandchildren and our great grandchildren. If we want this area to be here, we have to take the long view.”— Eva Hillmann, Ph.D., Coastal Scientist, Pontchartrain Conservancy.
“In 50 years, I’m not going to be here to enjoy the fruits of it, and if it don’t work, I’m not going to be here in 50 years to tell they they’re wrong. Yeah, that’s a good plan.”— Dean Blanchard, Shrimp Processor, Grand Isle
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