Bayou Dupont Ridge Creation and Marsh Restoration (BA-48)

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Problems: There is widespread historic and continued rapid land loss within the project site and surrounding areas resulting from subsidence, wind erosion, storms, and altered hydrology. Land loss data provided by the U.S. Geological Survey indicates that loss was occurring at a rate of 1.7% per year prior to construction. The natural limits of Bayou Dupont were difficult to determine in some areas because land loss was causing a merge of the bayou to adjacent water bodies. Natural tidal flow and drainage of patterns that once existed through the bayou were circumvented by the increasing area of open water.

Restoration Strategy: Project goals included: 1) creating and nourishing approximately 390 acres of marsh through sediment pipeline delivery from the Mississippi River; and   2) creating over two miles of ridge (10.5 acres of ridge habitat) along a portion of the southwestern shoreline of Bayou Dupont. Sediment from the river was hydraulically pumped to the project site to construct both the marsh and ridge features and additional material was dredged from Bayou Dupont to cover the ridge. The ridge is designed to mimic the configuration of other natural ridges within the watershed, and includes a constructed elevation conducive for the growth of native vegetation such as live oak, hackberry, and yaupon. The ridge is helping to redefine the limits of Bayou Dupont and reestablish the natural bank that once flanked the bayou and  protected adjacent marshes.

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Location: This project is located within the Barataria Basin in Jefferson and Plaquemines Parishes. The marsh creation area is located along Bayou Dupont southeast of the waterbody known as the Pen.

Progress to Date: Construction began in the Fall of 2014 in conjunction with the Mississippi River Long Distance Sediment Pipeline Project (BA-43EB) and Bayou Dupont Sediment Delivery-Marsh Creation #3 (BA-164). Construction of the Bayou Dupont (BA-48) portion was completed in fall of 2015.

This project is on Priority Project List 17.
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Raccoon Island Shoreline Protection/ Marsh Creation (TE-48)

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The Isles Dernieres barrier island chain is experiencing some of the highest erosion rates of any coastal region in the world. Raccoon Island is experiencing shoreline retreat both gulfward and bayward, threatening one of the most productive wading bird nesting areas and shorebird habitats along the gulf coast.

An existing demonstration project on the eastern end of the island, Raccoon Island Breakwaters Demonstration project (TE-29), has proven that segmented breakwaters can significantly reduce, and perhaps even reverse, shoreline erosion rates. The primary goal of this project is to protect the Raccoon Island rookery and seabird colonies from the encroaching shoreline by: 1) reducing the rate of shoreline erosion along the western, gulfward side and 2) extending the longevity of northern backbay areas by creating 60 acres of intertidal wetlands that will serve as bird habitat. This project has been separated into two construction phases, Phase A and Phase B. Phase A includes the construction of eight additional segmented breakwaters gulfward of the island and immediately west of the existing breakwaters demonstration project and an eastern groin that will connect existing Breakwater No. 0 to the island. Phase B involves the construction of a retention dike along the northern shore to create a back bay enclosure that will be filled with sediments dredged from the bay and/or gulf, followed by vegetative plantings.

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The project is located in the Terrebonne Basin on the western-most island of the Isles Dernieres barrier island chain in Terrebonne Parish, Louisiana.

This project was selected for engineering and design funding at the January 2002 Breaux Act Task Force meeting. Construction funding for Phase A was approved in October 2004. Request for Phase B construction funding is anticipated to occur in January 2008.

This project is on Priority Project List 11.

The Sponsors include:

Federal Sponsor: NRCS

Local Sponsor: CPRA

Hydrologic Restoration and Vegetative Planting (BA-34-2)

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Problems:
The Lac des Allemands River Basin Initiative identified the following specific problems within the Lac des Allemands Watershed: drainage impairments; water quality impairments; loss of marsh; and decline of cypress forest. Many years of study by Louisiana State University researchers in these swamps have demonstrated that, because of impoundment, subsidence, and inadequate accretion of sediments and organic matter, some areas are already highly stressed and converting to open water, floating aquatic plants, and fresh marsh. Also, the Coast 2050 report suggests that other areas of the swamps throughout the basin will likely convert to open water or floating marsh by the year 2050. These problems are caused by the loss of river water along with the associated sediment and nutrients necessary for swamp health. The loss of river water can be attributed to the leveeing of the Mississippi River. Impoundment caused by roads, drainage canals, and spoil banks is also a major cause of degradation of these swamps.
Restoration Strategy:

The original proposed restoration strategy included installing two small siphons (averaging 400 cubic feet per second) to divert water from the Mississippi River; gapping spoil banks on Bayou Chevreuil; gapping spoil banks along the borrow beside Louisiana Highway 20; installing culverts under Louisiana Highway 20; improving drainage in impounded swamps; and planting cypress and tupelo seedlings in highly degraded swamp areas.

The proposed diversion from the Mississippi River was to bring fresh water, fine-grained sediments, and nutrients into the upper des Allemands swamps, which would have helped maintain swamp elevation, improve swamp water quality, and increase productivity and regrowth of young trees as older trees die. However, after hydrologic modeling and more detailed engineering/design and cost estimation, it was determined that the siphon would cost far more than originally anticipated. For that reason, the CWPPRA Task Force approved the project sponsors’ request to re-scope the project to eliminate the siphon feature, and to focus on the remaining project features.

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Location: The project is located West of Lac des Allemands in St. James Parish, Louisiana, south of the town of South Vacherie, bordered on the south by Bayou Chevreuil, and on the east by LA Highway 20.

Progress to Date: The Louisiana Coastal Wetlands Conservation and Restoration Task Force approved Phase 1 funding in January 2001. In June 2013, the Task Force approved a request to change the scope of the project to eliminate a siphon feature and focus on the remaining original hydrologic restoration and vegetative planting project features. The Louisiana Coastal Protection and Restoration Authority performed the engineering and design services. Design was completed in October 2015 and Phase 2 funds for construction was approved by the Task Force in January 2016. Construction activities for excavation and placement began in October 2017 and ended on December 20, 2017, vegetative plantings occurred in late January, and officially completed on February 2, 2018.

The three (3) principal project features included:

1. Eight (8), 400-foot-long, strategically designed gaps were cut in the northern Bayou Chevreuil spoil bank to reverse the effects of impoundment;

2. Sixteen (16) spoil placement areas were created on each side of the channel banks; (1 placement area on both sides of each gap) to beneficially use the dredged material on site;

3. Seven hundred (700) Bald Cypress and one hundred (100) Water Tupelo saplings were planted in the constructed spoil placement areas to start swamp regeneration and swamp productivity.

This project enhanced 2,395 acres of swamp habitat that would have continued to degrade without the project.

This project is on Priority Project List (PPL) 10.

The sponsors include:

Federal Sponsor: U.S. Environmental Protection Agency

Local Sponsor: Coastal Protection and Restoration Authority (CPRA)

 

 

Black Bayou Hydrologic Restoration (CS-27)

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The purposes of the Black Bayou Hydrologic Restoration
project are to (1) restore coastal marsh habitat, and (2) slow
the conversion of wetlands to shallow, open water in the
project area. The project limits the amount of saltwater
intrusion into the surrounding marsh and canals from the
GIWW and reduces erosion caused by wave action from
nearby boats and tides.

A 22,600-foot rock dike was placed on the southern spoil
bank of the GIWW. A barge bay weir (70-foot bottom
width) was constructed in Black Bayou Cutoff Canal. Weirs
with boat bays (10-foot bottom widths) were constructed in
Burton Canal and Block’s Creek. A collapsed weir was
plugged and replaced by a fixed crest steel sheet-pile weir
with a state-of-the-art, self-regulating tidegate. Spoil
material from weir installation and the dredging of access
routes was deposited in nearby open water areas to the
height of marsh elevations. The $3 million construction
contract included installation of 55,000 marsh plants over the
next two planting seasons.

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This project, sponsored by the National Marine Fisheries
Service and the Louisiana Department of Natural Resources,
is a 25,529 acre wetland located in Cameron and Calcasieu
Parishes, Louisiana. Bordered by the Gulf Intracoastal
Waterway (GIWW), Sabine Lake, Black Bayou, and Gum
Cove Ridge, the project area consists of tidally-influenced
intermediate and brackish marshes.

Construction is completed. Installation of vegetative
plantings were completed in April 2002. The monitoring
plan was finalized in March 2000, and monitoring has
begun.

This project is on Priority Project List 6.

Federal Sponsor: NOAA 

Local Sponsor: CPRA

Bayou Cane Marsh Creation (PO-181)

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Problems:
In 2005, the marshes in the North Shore Mapping Unit sustained severe damage due to Hurricane Katrina. Hundreds of acres of emergent marsh within this mapping unit were lost, resulting in hundreds of acres of shallow open water and scour ponds averaging about 2 ft deep. USGS calculated a 1984 to 2016 area loss rate of -0.91 % per year. Currently there is one area along the shoreline that looks as if a breach is forming. This area also has a small pond immediately behind the critical shoreline. If there were a breach in this area it would allow direct connection between the fresher interior marshes and higher salinity waters of Lake Pontchartrain.
Restoration Strategy:
The overall goal of this project is to restore marshes that were lost and/or damaged due to the effects of Hurricane Katrina. Restoring the marshes should reduce salinity effects on interior emergent marshes.
The proposed features of this project consist of filling approximately 384 acres of shallow open water and nourishing an additional 65 acres of fragmented and/or low marsh with material hydraulically dredged from Lake Pontchartrain. Target settled marsh elevation would be +1.2 NAVD 88, but will ultimately correspond to surrounding healthy marsh.
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Progress to Date:
This project was approved for Phase I Engineering and Design on February 9th, 2018.
This project is on Priority Project List (PPL) 27.
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Goose Point/Point Platte Marsh Creation (PO-33)

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Interior ponding and, to a lesser extent, shoreline erosion are the major causes of wetland loss in the project area. Loss rates were highest during the period from 1956 to 1978. Those high loss rates were associated with hydrologic alterations which allowed salt water to penetrate the fresher marshes. During the transition to a more brackish plant community, large ponds were formed. A narrow strip of land separates those ponds from Lake Pontchartrain. Although the shoreline erosion rates are relatively low, the shoreline is already breached in several areas, and marsh loss in the interior ponds is expected to increase if the shoreline fails.

The goal of this project is to re-create marsh habitat in the open water behind the shoreline. This new marsh will maintain the lake-rim function along this section of the north shore of Lake Pontchartrain by preventing the formation of breaches into interior ponds.

Sediment will be dredged from Lake Pontchartrain and contained in cells within the interior ponds to create approximately 417 acres of marsh. In addition, 149 acres of degraded marsh will be nourished with dredged material. Marsh will be created to widen the shoreline so that the ponds will not be breached during the course of normal shoreline retreat.

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The project is located on the north shore of Lake Pontchartrain between Fountainebleu State Park and Louisiana Highway 11 and within the Big Branch Marsh National Wildlife Refuge in St. Tammany Parish, Louisiana. The project area at Goose Point also includes a portion of the St. Tammany State Wildlife Refuge.

On February 12, 2009, a final inspection of the project site was conducted. All construction activities are complete.

This project is on Priority Project List 13.

 

Federal Sponsor: USFWS

Local Sponsor: CPRA

New Cut Dune and Marsh Creation (TE-37)

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* Problems:  New Cut was first formed in 1974 when the eastern end of Trinity Island was breached during Hurricane Carmen. This breach was further widened by Hurricane Juan in 1985 and Hurricane Andrew in 1992. — The Isles Dernieres shoreline is one of the most rapidly deteriorating barrier shorelines in the U.S., exhibiting a pattern of fragmentation and disintegration.  — With regard to long shore sediment transport systems or the movement of beach material by waves and currents, the islands have ultimately become sources of sediment themselves leading to an ever-decreasing volume of sediment.

* Restoration Strategy: The purpose of this project was to close the breach between Trinity and East Islands through the direct creation of beach, dune, and marsh habitat. This project also lengthened the structural integrity of eastern Isles Dernieres by restoring the littoral drift by adding sediment into the nearshore system (restoring about 8,000 linear feet of barrier island).
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* Location: New Cut is the breach between East and Trinity Islands in the Isles Dernieres barrier  island chain. The cut is bordered on the north by Lake Pelto, on the west by Trinity Island, on the east by East Island and on the south by the Gulf of Mexico, in Terrebonne Parish, Louisiana.
* Progress to Date: A rock dike and approximately 2 million cubic yards of dredged material reconstructed a dune and marsh platform to protect the shoreline from erosion and to restore interior marsh lost from subsidence and saltwater intrusion.
Phase 2 (construction) funding was initially approved at the January 2001 Louisiana Coastal Wetlands Conservation and Restoration Task Force meeting and additional funds allocated in 2006 to account for change in borrow site and post-hurricane increased construction costs. Dredging was completed July 2007. About 8,000 linear feet of barrier island was restored by placing approximately 850,000 cubic yards of material. New Cut was closed through the construction of a dune platform matching the dune elevations on the east and west, strengthening the connection between East and Trinity Islands. Nine species of native barrier island vegetation were planted along with over 17,000 linear feet of sand fencing. No maintenance is anticipated over the 20-year design life.
* This Project is on Priority Project List (PPL) 9.
* Federal Sponsor:
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  Dallas, TX
  (214) 664-6722
* Local Sponsor:
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