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Louisiana Coastal Wetlands
Marsh Terracing Project
Problems: Louisiana has the highest coastal wetlands loss
rate of any state in the nation comprising more than 1,500 square miles of marsh
over the past seven decades. Coastal marshes have been deteriorating since man-made
navigation channels changed the natural water-flow patterns on the landscape,
allowing saltwater to intrude into areas of the marsh where vegetation is less
tolerant of high salinity. When this happens, the stressed vegetation dies,
which creates large areas of shallow open water and broken marsh. These open-water
areas are characterized by relatively unproductive turbid water void of any
submersed aquatic vegetation. Marshes adjacent to these large open-water areas
are currently experiencing severe erosion caused by wind-generated waves. Twenty-five
to thirty-five square miles of the coast’s emergent wetlands are being replaced
every year by open-water habitats.
Restoration Strategy: Terraces will be constructed in water
depths ranging from one to two feet. Each terrace, arranged in an alternating
pattern at 30-degree angles (which makes them look like duck wings from the
air), will be 1,000 feet long, 40 feet wide at its base and about 10 feet wide
at its top. The surface of each terrace will be approximately two feet above
water level and will be planted with vegetation to reduce erosion. They will
be designed in a “V” shape so that regardless of the wind direction, calm water
will exist on the downwind side of the terrace.
Purpose: The project calls for the construction of approximately
27 linear miles of terraces that will have several functions. The resulting
calm water will provide conditions suitable for submersed aquatic vegetation
production while the actual terrace crown will provide nesting sites for resident
wildlife like the American alligator and mottled duck.
Submersed aquatic vegetation and seeds of annual marsh plants are the staples
provided by healthy Louisiana coastal marshes that have historically sustained
millions of ducks through the fall and winter. The reduction in wave energy
will result in reduced shoreline erosion surrounding the project areas. To
ensure longevity of each terrace, plugs of smooth cordgrass ( Spartina alterniflora
) were planted at the water’s edge. The project will increase the carrying
capacity of wintering, migration, and breeding habitat for wetland-dependent
migratory birds, improve and increase fisheries habitat, and will contribute
directly to the objectives of the Gulf Coast Joint Venture.
Location: Approximately 24 miles southeast of Lake Charles,
LA (Cameron Parish)
Acres Impacted: 6,000 acres
Habitat Type: Coastal Marsh
Submerged Aquatic Vegetation
Partners: Ducks Unlimited, Inc
North American Wetlands Conservation Council
Louisiana Department of Wildlife and Fisheries
Louisiana Department of Natural Resources
U.S. Fish and Wildlife Service
USDA Natural Resources Conservation Service
U.S. Geological Survey
Louisiana Department of Agriculture and Forestry
Cameron Parish Police Jury
Miami Corporation
Sweetlake Land and Oil
Timeline: Construction was completed in spring 2003 
DU Contact: Chad Courville
Regional Biologist
646 Cajundome Blvd., Ste. 180
Lafayette, LA 70506
(337) 291-3068
ccourville@ducks.org
Louisiana Habitat Projects
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