A series of black rectangles planted with marsh grass were towed into Lake Pontchartrain near the Bucktown Marina on Thursday as part of a pilot project aimed at providing another tool for wetland restoration.
The rectangles, or “islands,” are 5- by 20-foot mats made of recycled plastic; they support plantings of marsh grass.
The hope is they can survive and stay in place through the sometimes rough waves on the lake, protecting a 31/2-acre marsh built to mitigate the construction of the marina and provide a model for future projects.
The project includes 17 islands arranged between 60 and 100 feet from the shoreline.
If all goes as planned, the plantings in the mats will grow, forming a habitat, building sediment and lessening the impact the lake’s waves have on the shoreline marsh.
“This will buffer that area and protect it,” Jefferson Parish Environmental Affairs Director Marnie Winter said.
Building artificial islands has long been a tool of wetland restoration.
However, the projects usually involve building the islands up from the bed of the body of water involved — an expensive process.
Typically, a one-acre island requires about 6,000 cubic yards of fill, at a cost of about $10 a cubic yard, Lake Pontchartrain Basin Foundation Director John Lopez said.
The floating islands, by contrast, are tethered to the lake bed only by a chain and anchor, potentially giving the restoration project more bang for the buck.
“If you can put these islands in a water body without building a column, then you can cover a lot of acres,” Lopez said.
The project was funded by a $50,000 grant from the University of New Orleans Foundation; the mats were assembled Thursday by a group of about 50 volunteers from Entergy.
The volunteers also were involved in a similar project involving floating islands near Isle de Jean Charles in Terrebonne Parish.
While the pilot project is relatively small-scale at the moment, the use of islands in the lake is particularly important, since much of the shore is lined with rocks intended to protect levees from erosion.
Marshes in the lake would provide an important habitat for fish, shrimp, crabs and other marine life, providing vegetation that allows those species to hide from predators, Lopez said.
“This could be reproduced in Lake Pontchartrain and other areas of the coast,” he said.
Jefferson Parish President John Young praised the project, saying that in addition to its environmental benefits, it would help to mitigate storm surge from the lake.
The parish is working with UNO on a way to monitor the floating islands and determine whether this technique is suitable for other areas.
Much of the Lake Pontchartrain shoreline was once covered in marshes that were destroyed by a variety of activities, including dredging and urbanization, and Winter said it may eventually be possible to reverse some of that damage.
“It’s worked in other places. I think it’ll work here,” Winter said.
Copyright © 2011, Capital City Press LLC • 7290 Bluebonnet Blvd., Baton Rouge, LA 70810 • All Rights Reserved