What are these (South Louisiana)

Looks likes a combination of letters and numbers

It looks like the tortured path set up for diversions. Are there any diversions or sediment carrying waterways near here?

Pecan Island Terracing Project

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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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LINK

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The marshland was transformed into dry pastureland 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. This project will convert areas of open water back to vegetated marsh through the construction of earthen terraces.

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They have the same thing in PAC.


Google Map

It's a marsh rebuild/ ridge rebuild attempt.
Not sure of the funding for each, but I'm sure CPRA is somewhat involved in them.

Another one I've come across is in Venice, Alexis Bay off Batiste Collette. 29.22588; -89.331734.

There are a number of similar projects in the Cameron and Calcasieu Parish marshes, the marsh on the east side of Lake Calcasieu (behind the weirs for those that know the area), west of Black Lake, in the Sabine marsh, etc, etc...

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Do they work?

It says they've been there for 14 years and I don't see no land around them.

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doesnt look like it but I bet it makes for some damn good duck hunting if you're lucky enough to have a lease or own land out there.

If built in the right place. It's a very passive management/restoration process that relies on sediment flow/settling.

The idea is that the terraces will capture sediment and cause it to settle. This eventually builds up the marsh bottom, and with the sediment settling out of the water column, sunlight is able to reach the marsh bottom and allow vegetation to grow. The terrace fields are built such that they are oriented with the predominant winds for that area. The straightline terraces were designed as a grid, while the newer "duck wing" terraces are staggered and "inverted" so that sediment is trapped between the rows.

The terraces I have seen personally have definitely accomplished the sediment capturing part of the plan, but only those in high sediment flow areas. If you have very little sediment in the water column, it could take decades to see measurable results. It may take decades for vegetation to start spreading in between the terraces.

Material used to build the terraces is critical to the success. I've seen some built put of marsh "soils", and the amount of organic matter in the soil allows water in, and the terraces erode away in a matter of years. The strongest ones are made of very dense clay, and will take decades to erode, even if left unvegetated. The problem is, planting these is difficult, and the plants spresd very little because of how dense the clay is.

The best ones are a clay loam...strong enough to withstand wind and wave action, but allows vegetation to spread.

Almost every terrace project includes plantings. The sides are often planted with cordgrass to stabilize them and introduce a seed source for future growth.

Terraces also provide pretty good mottled duck nesting habitat.

I'm from up near I-20 so excuse me but I thought they may be crawfish ponds.

Guess the salt water wouldn't work for that