Terrebonne Bay Marsh Creation-Nourishment

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Emergent marshes north of Terrebonne Bay have been
eroding as fast or faster than almost any other marshes
along coastal Louisiana. As these marshes convert to
shallow open water, the tidal prism will increase which will
in turn increase the frequency and duration of tides north
of Terrebonne Bay. This increasing tidal prism is likely
to increase the future interior marsh loss rates for those
marshes directly north of Terrebonne Bay. These marshes are
important for their habitat values as well as serving to slow
the progress of highly saline waters that threaten the lower
salinity marshes north and west of Madison Bay and in the
Lake Boudreaux basin. The
continued loss of these marshes has directly contributed to
the ongoing flooding problems of many communities along
Bayou Terrebonne including the town of Montegut.

The primary goal of this project is to fill shallow open water
areas and nourish marshes north of Terrebonne Bay/Lake
Barre thereby reducing the tidal prism north of Terrebonne
Bay and
interior land loss from tidal scouring. Specific Goals: 1)
Create 365 acres of intertidal marsh in shallow open water
and nourish 299 acres of fragmented marsh within the
project area reducing
water exchange between Terrebonne Bay and interior lakes
during tidal and small storm events. 2) Reduce erosion along
16,000 ft of the northern Terrebonne Bay shoreline.

The proposed features of this project consist of filling
approximately 365 acres of shallow open water and
nourishing approximately 299 acres of very low or
fragmented marsh with material hydraulically dredged from
Terrebonne Bay/Lake Barre. Containment dikes will be
degraded/gapped within 3 years of construction to allow
for greater tidal and estuarine organism access. This project
could be one part of a phased comprehensive plan to protect
the northern shoreline of Terrebonne Bay and the interior
marshes from further erosion and reduce the tidal prism.
The project would result in approximately 353 net acres of
marsh over the 20-year project life.

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This project is located in Region 3, Terrebonne Basin,
Terrebonne Parish, along the northern shoreline of Lake
Barre/Terrebonne Bay near Bayou Terrebonne continuing
east a short distance past Bayou Chitique.

This project is on Project Priority List (PPL) 20.

The Terrebonne Bay Marsh Creation-Nourishment project sponsors include:

Keep up with this project and other CWPPRA projects on the project page.

 

Cameron-Creole Watershed Grand Bayou Marsh Creation

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Approximately 14,390 acres (32%) of the Cameron-Creole
Watershed Project (CCWP) marshes were lost to open water
from 1932 to 1990 at an average loss rate of 248 acres/year
(0.55 percent/year) due to subsidence and saltwater intrusion
from the Calcasieu Ship Channel. The
CCWP was implemented by the NRCS in 1989 to reduce
saltwater intrusion and stimulate restoration through
revegetation. Hurricanes Rita and Ike in 2005 and 2008
breached the watershed levee scouring the marsh and
allowing higher Calcasieu Lake salinities to enter the
watershed causing more land loss. The Calcasieu-Sabine
Basin lost 28 square miles (17,920 acres) (4.4%) as a result
of Hurricane Rita (Barras et al. 2006). Land loss is estimated
to be 1.33 percent/year based on USGS data from 1985 to
2009 within the extended project boundary.

Project goals include restoring and nourishing hurricane-scoured
marsh in the Cameron Prairie National Wildlife
Refuge and adjacent brackish marshes of the Calcasieu Lake
estuary. Approximately 3 million cubic yards of material
would be dredged from a borrow site proposed in Calcasieu
Lake and placed into two marsh creation areas north of
Grand Bayou to restore 609 acres and nourish approximately
7 acres of brackish marsh. The borrow site would be
designed to avoid and minimize impacts to oysters and other
sensitive aquatic habitat. Tidal creeks would be constructed
prior to placement of dredge material and retention levees
would be gapped to support estuarine fisheries access and
to achieve a functional marsh. The project would result in
approximately 534 net acres of brackish marsh over the 20-
year project life.

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This project is located in Region 4, Calcasieu-Sabine Basin,
Cameron Parish, 6 miles northeast from Cameron, LA, on
the Cameron Prairie NWR and Miami Corporation property
north of Grand Bayou.

This project is on Project Priority List (PPL) 20.

The Cameron-Creole Watershed Grand Bayou Marsh Creation sponsors include:

Keep up with this project and other CWPPRA projects on the project page.

 

South Grand Chenier Marsh Creation-Baker Tract

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Marshes within Hog Bayou Watershed mapping unit are stressed due to limited freshwater input and seasonal salinity spikes exacerbated by construction of the Mermentau Ship Channel. Other contributors to land loss in the area are subsidence, compaction, and erosion of organic soils. Currently, the project area is characterized as large, open water with degraded areas of wetland vegetation and low organic production. The dredging of the Mermentau Ship Channel increased tidal amplitude and salt water intrusion into the watershed.

The goal of the project is to create new wetland habitat, restore dredged marsh, and reduce wave erosion of organic soils. the project would promote the expansion of emergent marsh and submerged aquatic vegetation throughout the project area. Material dredged from the Gulf of Mexico will be used to create and nourish approximately 420 acres of marsh. Smooth cordgrass will be planted throughout the area. To help facilitate estuarine fisheries access, constructed retention levees will be degraded and approximately 11,756 linear feet of tidal creeks will be constructed.

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The project is located in planning Region 4, Mermentau Basin in Cameron Parish within the Hog Bayou Watershed Coast 2050 mapping Unit. The mapping unit is bordered by Lower Mud lake to the west, the Gulf of Mexico to the south, Rockefeller Refuge to the east, and Louisiana Highway 82 to the north.

This project is on Priority Project List (PPL) 23. This project is currently in the Engineering and Design Phase.

The South Grand Chenier Marsh Creation – Baker Tract project’s sponsors include:

  • Federal Sponsor: Natural Resources Conservation Service
  • Local Sponsor: Coastal Protection and Restoration Authority

 

Learn more about this project (ME-32) and others on CWPPRA’s project page.