Fourteen Years of Coastal Progress

Since the Breaux Act inception in 1990, 131 coastal projects have been authorized to protect and restore Louisiana’s coastal wetlands. Of the 66 projects completed, some have worked better than others, but each has contributed to a base of knowledge about what works, laying a foundation for the future. Five significant projects, each by a different federal lead agency, are featured here as examples.

Pecan Island Terracing —
(project types 6, 7, and 8)

Lead Agencies: NMFS, LDNR

Location: Southwestern Vermilion Parish

Status: Completed September 2003

Problems: This formerly healthy marsh was surrounded by dikes and drained in the 1950s. Subsequently, the soil subsided one to two feet. Recently, perimeter levees were lost and the area was converted into a shallow open-water lake with a net loss of habitat.

Restoration Strategy: Convert the open water back to vegetative marsh by creating earthen terraces, which are planted with marsh vegetation. By reducing wave action and turbidity, submerged aquatic growth will be promoted.

Goal: Create/Restore 383 acres and protect 59 acres.

Accomplishments: A total of 198,700 linear feet of earthen terrace have been constructed and planted and are now protecting the adjacent marshes, while promoting their expansion.

West Bay Sediment Diversion —
(project types 1 and 6)

Lead Agencies: COE, LDNR

Location: West bank of the Mississippi River, above Head of Passes in Plaquemines Parish

Status: Completed 20,000 cubic-foot-per-second channel November 2003; expand to 50,000 cfs in 2006

Problems: Marshes in the West Bay area have been and are subsiding and converting to open water at a very rapid rate due to a lack of sediment and freshwater input.

Restoration Strategy: Construct a conveyance channel for large-scale diversion of sediments carried by fresh water from the Mississippi River into West Bay.

Goal: Create, nourish, and maintain 9,831 acres of fresh to intermediate marsh in the West Bay area.

Accomplishments: Diversion channel carries fresh water and sediments into West Bay at an average flow rate of 20,000 cfs. More than 200 acres of new wetlands were created with 1.6 million cubic yards of material dredged during construction.

Replace Three Sabine Refuge Water Control Structures —
(project types 2 and 3)

Lead Agencies: USFWS, LDNR

Location: Cameron Parish, nine miles south of Hackberry

Status: Construction completed in 2000 and 2001. As of December 2004, with the exception of one bay on each of two structures, the project is fully operational.

Problems: The existing water control structures at the Hog Island Gully,West Cove and Headquarters canals were inadequate to discharge excess water or deter saltwater intrusion—actions necessary to counteract hydrology changes, erosion and hurricane damage in the area. The structural deficiencies were contributing to the ongoing deterioration of thousands of acres of marsh due to saltwater intrusion and the waterlogging of marsh vegetation. Much of the marsh area, classified as fresh-to-intermediate in 1949, had become brackish-to-saline by 1999 and exposed to erosion by large expanses of open water, which had replaced the vegetation.

Restoration Strategy: Replace the inadequate control structures with new structures, which have substantially greater volume and management capacity.

Goal: Maintain intermediate and brackish vegetation communities and increase submerged vegetation over 953 acres.

Accomplishments: Water salinity has decreased up to 75 percent within the project area and, while data are still being analyzed, the positive benefits of increased submerged vegetation are clearly indicated.Water levels relative to the marsh surface have also been stabilized.

Raccoon Island Shoreline Protection/Marsh Creation—
(project type 5)

Lead Agencies: NRCS, LDNR

Location: The western-most island of the Isles Dernieres barrier island chain in Terrebonne Parish

Status: Demonstration project completed in 1997. Construction for project expansion to begin in June 2005.

Problems: The Isle Dernieres barrier island chain has experienced some of the highest erosion rates of any coastal region in the world. Raccoon Island’s shorelines have retreated, threatening one of the most productive bird habitats on the Gulf Coast.

Restoration Strategy: Reduce shoreline erosion rates by placing segmented rock breakwaters on the gulf side of the island and create additional island habitat with dredged sediments.

Goal: Reduce shoreline erosion by protecting this 150-acre barrier island from waves generated in the Gulf of Mexico.

Accomplishments: The demonstration project involved placing eight 300-footlong breakwaters in the gulf, 300 feet out from the shoreline.While the goal was to reduce erosion, in fact, the end result was the expanse between the breakwaters and the island shoreline filled in with accreted material, growing the island and reversing the erosion rate. Additionally, a previously unseen, bonus phenomenon occurred—deposits of material also occurred on the gulf side of the breakwaters.

Isles Dernieres Restoration— East and Trinity Islands—
(project type 5)

Lead Agencies: EPA, LDNR

Location: Terrebonne Parish, south of Cocodrie

Status: Completed June 1999

Problems: East, Trinity and Raccoon islands comprise three of the five islands in the Isles Dernieres barrier islands chain.Without restoration, East Island was expected to be gone by 1998 and Trinity by 2007. Both islands protect interior wetlands and serve as habitat for waterfowl and other migratory species.

Restoration Strategy: Construct temporary dikes in the bay behind the islands. Then create sloping elevated dune and marsh platforms by filling the area between the island’s dunes and dikes with sediment dredged from Lake Pelto.

Goal: Restore East and Trinity islands.

Accomplishments: About seven and a half miles have been restored. East Island was expanded by 300 acres and Trinity by 500. Both islands now have dune elevations of eight feet, new vegetative plantings and sand fencing.