If You Float It, They Will Come
by Ryck Lydecker
To anyone interested in coastal Louisiana, it’s no secret that the state has lost thousands of acres of valuable marshland and critical wetlands habitat to erosion over the years. Most attempts to restore the marshes rely on labor-intensive marsh grass planting that has proven only marginally effective, or expensive dredge-and-fill operations. But a promising new technique is taking root — literally! — in Terrebonne Parish. There, volunteers are using a “floating islands” concept, and it’s outperforming all expectations.
The project, started in September 2011 by the Louisiana Chapter of the Coastal Conservation Association (CCA), uses lightweight slabs of recycled plastic to hold marsh grass plugs, which is like a flat for starting tomato plants. The slabs, or islands, are then towed into place with a small boat and anchored in shallow water, down current from existing natural marsh. The 8- to 10-inch-thick islands, roughly 5 by 8 feet, hold up to 60 plugs. Over time, the plugs grow root systems down into the sea floor. The plants can then begin to trap sediments and eventually this buildup will tie the “island” back into the remaining natural marsh.
CCA members and students from nearby Pointe-aux-Chenes Elementary School joined Shell Oil Company employees and members of a local Native American tribe to plant thousands of marsh grass plugs last fall at four sites around Isle de Jean Charles, an area where just slivers of natural marsh remain due to severe erosion. That project created 195 islands or about 1,560 linear feet of floating marsh. Monitoring since then has found that plants in the islands are healthier and greener than those in the surrounding marsh. In many places the plants, now 3 to 4 feet tall, completely cover the islands and, even more encouraging, are spreading back toward the adjacent natural marsh as hoped.The project is one of four Gulf Coast restoration projects undertaken by the CCA Building Conservation Trust with seed money from Shell Oil and matched by local dollars, with additional support from businesses and America’s Wetland Foundation.
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