re: What are these (South Louisiana)

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The Pecan Island Terracing Project area was originally marshland that was transformed into
dry pasture land in the mid 1950’s by constructing continuous dikes and pumping out the
water. Deterioration and loss of the perimeter levees in recent years has converted the entire
area into a shallow, open water lake with a few small marsh islands. The project will convert
areas of open water back to vegetated marsh through the construction of earthen terraces,
which were completed in August, 2003. The terrace construction will include breaks between
the terraces to facilitate sediment settling. Submerged aquatic vegetation growth will be
promoted in the terrace area due to reduced turbidity and wave action. Vegetative plantings
were completed in September, 2003.

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The Pecan Island Terracing (ME-14) project is located five miles north of the Gulf of Mexico
just south of Pecan Island and Hwy 82 in the Lakes Sub-basin of the Mermentau Basin,
Vermilion Parish, Louisiana. The total project area comprises 3,753 acres (1,519 ha) of
brackish marsh and open water. Area 1 is primarily open water and was formerly pasture land
of approximately 1,938 acres (784 ha). Area 2 consists of 1,715 acres (694 ha) of brackish
marsh and open water.
The project features include construction of 197,000 linear feet (60,046 m) of terraces in 500
ft (152.4 m) sections with a 50 ft (15.24 m) break between each terrace, creating
approximately 344 terraces. Terraces run east to west in a staggered gap formation. The
terraces were constructed by depositing borrow material with a 40 ft (12.19 m) berm for a
terrace with 4:1 side slopes and a top width of 10 ft (3.04 m). Initial constructed elevation was
approximately 3.75 ft (1.14 m) NAVD 88 which in 5 years should have a final settled
elevation approximately 1 ft above marsh elevation. The dredged material was deposited such
that the terrace’s side slopes were 4:1 to conform to the natural angle of repose for the bottom
soil. Breaks were constructed to permit water to move in and out of the interior, which may
facilitate the settling of suspended soil particles. Spartina alterniflora (smooth cordgrass)
plugs were planted every five linear feet on both sides of terrace.
The Pecan Island Terracing Project was authorized by Section 303(a) of Title III Public Law
101-646, the Coastal Wetlands Planning Protection and Restoration Act (CWPPRA) enacted
on November 29, 1990 as amended and approved on the seventh Priority Project List. The
Pecan Island Terracing Project has a twenty–year (20 year) economic life, which began in
September 2003.

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