A Cornerstone for Coastal Restoration: The Mid-Barataria Sediment Diversion
By Rachel Rhode
, Manager, Climate Resilient Coasts & Watersheds
To restore Louisiana’s coast, we need a suite of large-scale restoration projects across the coast working together to deliver maximum benefits to reduce land loss, restore ecosystems, and maintain healthy and diverse habitat. In our “Restoration Project Highlights” series, we take a deeper look at specific projects from our list of Priority Projects, highlighting why they’re needed and hearing local perspectives on importance.
Louisiana’s Barataria Basin has experienced some of the highest rates of land loss in the country: Between 1932 to 2016, the region lost nearly 295,000 acres of land. This is due to a number of man-made and natural factors, such as the construction of Mississippi River levees and flood control systems, land subsidence and sea level rise.
The Mid-Barataria Sediment Diversion is a cornerstone restoration project in the state’s Coastal Master Plan. The diversion is being designed to strategically mimic the natural riverine processes that built the Mississippi River Delta and to help build and maintain land in the degraded Barataria Basin. Once constructed, the diversion will deposit enough sediment to build and maintain 30,000 acres of land over 50 years. The project will also work in tandem with other coastal restoration projects, such as marsh creation, by providing needed sediment and fresh water to sustain those projects.
A local’s take on the Mid-Barataria Sediment Diversion
Ted Falgout, the former director of Port Fourchon, talks to us about living in Barataria Basin and the changes he’s seen in the wetlands over his lifetime and why he’s a supporter of the Mid-Barataria Sediment Diversion.
What is the Mid-Barataria Sediment Diversion?
Located on the west bank of the Mississippi River just north of Ironton, La., the Mid-Barataria Sediment Diversion will build land by opening a series of gates built into the levee system during strategic times and using the natural energy of the river to capture and move sediment from the river through the channel and pump station to an outfall area, where it will be redistributed in adjacent degraded wetlands. Once constructed, the diversion will deliver a sustainable source of sediment that can begin to replenish the basin and influence the long-term resiliency of the coast to hurricanes, storm surge and continued land loss.
In addition to the 30,000 acres the diversion will build, the Coastal Protection and Restoration Authority (CPRA) has identified approximately 8,500 acres of marsh creation projects that can be sustained over time due to their proximity to the diversion. Projects like this that work synergistically can increase benefits and provide important long-term cost savings.
Below is an example of how the proposed Mid-Barataria Sediment Diversion might be built, which was presented by Coastal Protection and Restoration Authority project engineer Kodi Guillory during the 2018 State of the Coast conference in May.
What does a future without action look like?
Future with action assumes all projects in the 2017 Coastal Master Plan are operating.
What does a future without action look like?
What does a future with action look like?
How will the diversion benefit wildlife?
Large-scale diversions like Mid-Barataria provide multiple benefits by building and sustaining thousands of acres of wetland habitat. At a basin-wide scale, the diversion will help sustain diverse coastal ecosystems that contain numerous species of fish and wildlife.
Since leveeing of the river decades ago, the Barataria Basin has become saltier, causing saltwater species to shift northward from the Gulf toward New Orleans. Meanwhile, freshwater species have lost habitat as the historically fresher inland basin areas have become more salty. Without restoration, these changes will continue, resulting in a loss of species that rely on productive freshwater and intermediate wetland habitats.
Diversion operations will likely cause a shift in this current distribution of species and habitat, due to changes in freshwater and nutrient inputs. But without restoration, more land and habitat will be lost, impacting not only wildlife, but people that live in the region.
Credit: Audubon Louisiana
One species that thrives in the freshwater upper reaches of the Barataria Basin is the iconic Bald Eagle. The Bald Eagle has been brought back from the brink of extinction because of the banning of DDT and other organochlorines in 1972. In south Louisiana, this species has subsequently rebounded from a mere four nesting pairs 50 years ago to more than 350 pairs today.
The vast majority of these nesting Bald Eagles are found in Louisiana’s coastal freshwater wetlands, and we risk seeing a reduction in population if we continue losing these freshwater habitats. In contrast, the Mid-Barataria Sediment Diversion will freshen the upper estuary and is predicted to expand the availability of suitable Bald Eagle nesting and foraging habitat.
When will the diversion be constructed?
In April 2018, the U.S. Army Corps of Engineers announced it had identified time savings in the permitting process for the Mid-Barataria Sediment Diversion, moving the estimated permitting completion date up two years to November 2020. This is a substantial step forward in getting this diversion constructed on a timeline that matches the urgency of the crisis.
Because of the size and complexity of the project, an Environmental Impact Statement is needed to examine the potential impacts of the project, and to provide an opportunity for the public and interested stakeholders to share input prior to any permits being issued. The Draft Environmental Impact Statement is due out for public comment in November 2019.
In June 2018, CPRA announced that a construction contractor had been chosen to work alongside the diversion designers and engineers to provide early input on cost, scheduling and construction. This method, known as Construction Management At-Risk, is ideal for decreasing project costs and the construction timeline. The $1.4 billion diversion is expected to begin construction in 2020 and become operational by 2026.
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