Bayou Dupont Sediment Delivery – Marsh Creation and Terracing

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Wetlands in the Barataria Basin were historically nourished
by the fresh water, sediment and nutrients delivered by
the Mississippi River and its many distributary channels.
These sediment and nutrient inputs ceased following the
creation of levees along the lower river for flood control and
navigation. In addition, the construction of numerous oil and
gas canals along with subsurface oil and gas withdrawal has
exacerbated wetland loss in the area. From 1932 to 1990, the
Barataria Basin lost over 245,000 acres of marsh. From 1978
to 1990, the area experienced the highest rate of wetland loss
in coastal Louisiana.

The primary goal of this project is to create and nourish
approximately 144 acres of emergent intermediate marsh
using sediment from the Mississippi River, and constructing
9,679 linear feet of terraces. The proposed project includes
dredging sediment from the Mississippi River for marsh
creation by pumping the sediment via pipeline into an area of
open water and broken marsh. The proximity of the project
to the Mississippi River provides a prime opportunity to
utilize this renewable river sediment resource. The strategy
includes utilizing the access route and infrastructure
previously put into place for the BA-39 project. This project
will complement existing restoration projects in the area.

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CWPPRA Region 2, Barataria Basin, Jefferson and
Plaquemines Parishes. The general project area is about 10
miles south of Belle Chasse, LA and is west of LA Hwy
23 and north of the Myrtle Grove Marina. The project
is immediately adjacent to the completed CWPPRA
Mississippi River Sediment Delivery System – Bayou
Dupont (BA-39) project.

The project was approved for engineering and design at the
January 24, 2013 Task Force meeting. The E&D was
completed in the fall of 2014 and sponsors requested phase
2 funding at the January 22, 2015 Task Force meeting,
however, there was insufficient money available to fund
the entire project. In order to take advantage of the existing
mobilization of the Long Distance Sediment Pipeline
(LDSP) Project, the sponsors proposed to reduce the scope
of the project to fit within the available CWPPRA funding.
The Task Force approved the reduced scope Phase 2 funding
request at the May 14, 2015, Task Force meeting. The asbuilt
project features include 144 acres of marsh creation and
9,679 linear feet of terracing.

In addition, CPRA increased the marsh creation feature of
the project by utilizing contingency funding left over from
BA-43, thereby increasing the total marsh creation in the
area to an estimated 296 acres. Construction started in April
2016, and marsh creation was completed in November
2016. Terracing was completed in June 2017, and vegetative
plantings for the terraces are scheduled for the spring of
2018.

This project is on Priority Project List (PPL) 22.

The Bayou Dupont Sediment Delivery – Marsh Creation and Terracing sponsors include:

 

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Fritchie Marsh Creation and Terracing

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A significant portion of the Fritchie Marsh was lost due to
Hurricane Katrina. Post storm shallow open water areas
dominate the landscape which limits the effectiveness of the
PO-06 CWPRRA project. Wetlands in the project vicinity
are being lost at the rate -1.09%/year based on USGS
data from 1985 to 2015. These marshes cannot recover
without replacement of lost sediment, which is critical if the
northshore marshes are to be sustained.

Project goals include restoring and nourishing marsh.
Specific goals of the project are: 1) create approximately 291
acres of marsh; 2) nourish approximately 49 acres of existing
marsh; and 3) construct about 36,610 feet of earthen terraces
or 26 emergent acres.

An alternative analysis was conducted leading to the
selection of features and configuration to compliment and
work synergistically with the existing PO-06 project and
planned mitigation and restoration projects in the Fritchie
Marsh. A robust engineering cost is included to evaluate
increasing the project size if costs allow or adjust the
layout, if needed during Phase 1. Approximately 2 million
cubic yards of material would be placed confined to restore
291 acres and nourish approximately 49 acres of brackish
marsh. Material would be dredged from a borrow site in
Lake Pontchartrain. The borrow site would be designed to
avoid and minimize impacts to aquatic habitat and existing
shorelines. Approximately 26 acres of earthen terraces would
be constructed within various locations totaling approximately
36,610 feet or 523 acres of terrace field. All containment
dikes would be gapped or degraded no later than three years
after construction to facilitate the development of tidal marsh
functions supportive of estuarine species. The terraces would
be planted as well as 50% of the created marsh acres to
expedite colonization and enhance stabilization.

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Region 1, Pontchartrain Basin, St. Tammany Parish, located
approximately three miles southeast of Slidell, Louisiana. A
substantial portion of the project is located on Big Branch
National Wildlife Refuge.

This project was approved for Phase I Engineering and
Design in January 2016.

This project is on Priority Project List (PPL) 25.

The Fritchie Marsh Creation and Terracing sponsors include:

 

Terracing

CWPPRA Restoration Technique: Terracing

The goal of building terraces is to achieve some of the same objectives as full marsh creation but over a larger area of open water, where marsh creation alone is not feasible. Terraces are long, earthen berms that are built by mechanically dredging material and piling and shaping the material to a desired height. Most terraces average around 3 feet tall, with shallow side slopes and a wide base. This size and shape optimize the amount of terrace that falls in the intertidal zone and will support wetland vegetation.

The objectives of constructing terraces are several and depend upon the location in which they are built. These include acting as a sediment trap to help build new land, reducing wave fetch and erosion on adjacent marsh shorelines, creating habitat for fish and waterfowl, and improving water quality to promote the growth of aquatic vegetation. Terracing projects constructed under CWPPRA have achieved each of these goals, with sediment trapping being most evident near the openings of sediment-laden bays or navigational waterways.

Terracing has become a widely used technique that is expanding across the Gulf Coast because of the success and cost-effectiveness demonstrated through CWPPRA and privately funded projects. Although these features may not look like natural marsh and often use geometric configurations, they are able to perform a lot of the functions of natural marsh in areas that have become vast open water. Developing this cost-effective technique for use in areas that have few other restoration options is a testament to CWPPRA’s ability to adapt to funding constraints and a quickly changing environment.

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TV-12 Little Vermilion Bay Sediment Trapping

 

 

 

 

Cameron Meadows Marsh Creation and Terracing

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Significant marsh loss in the Cameron Meadows area is attributed to rapid fluid and gas extraction beginning in 1931, as well as Hurricane Rita and Ike. Rapid fluid and gas extraction resulted in a surface down warping along distinguished geologic fault lines. During the hurricanes of 2005 and 2008, the physical removal of the marsh coupled with subsequent low rainfall has resulted in the conversion of intermediate to brackish marsh to approximately 7,000 acres of open water. In addition to these losses, significant marsh loss has resulted from saltwater intrusion and hydrologic changes associated with storm damages.

The goal of the project is to restore approximately 400 acres of coastal marsh habitat and reduce the fetch by constructing approximately 12,150 linear feet of earthen terraces. Sediment will be hydraulically dredged from the Gulf of Mexico and pumped via pipeline to create approximately 380 acres of marsh (295 acres confined disposal and 85 acres unconfined disposal). Funds are included to plant approximately 180 acres. Approximately 12,150 linear feet of earthen terraces will be constructed in a sinusoidal layout to reduce fetch and wind-generated wave erosion. Terraces will be constructed to +3.0 feet NAVD88, 15 feet crown width, and planted. Terrace acreage will result in four acres of marsh above Mean Low Water.

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The Cameron Meadows Marsh Creation and Terracing project is located in Region 4, Calcasieu/Sabine Basin in Cameron Parish, approximately five miles northeast of Johnson Bayou and five miles north of the Gulf of Mexico.

This project is on Priority Project List (PPL) 22. The 30% Design Review meeting was completed July 2015 and the 95% Design Review was completed in October 2016. In January 2017, the CWPPRA Task Force approved CS-66 for Phase II Construction.

The Cameron Meadows Marsh Creation and Terracing project sponsors include:

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

Managing Agencies

For 25 years, the Coastal Wetlands Planning, Protection, and Restoration Act has provided the only joint Federal/State coastal restoration effort with a predictable and recurring funding stream designed to restore the vanishing wetlands of coastal Louisiana. The CWPPRA program continues to pursue a full slate of coastal restoration activities, and its progress and experience provide the foundation for restoration supported by one-time funding from various other sources. CWPPRA represents a collaborative effort and is managed by a Task Force comprised of five federal agencies and the State of Louisiana. CWPPRA’s Managing Agencies include:

U.S. Department of the Army – U.S. Army Corps of Engineers, New Orleans District

U.S. Environmental Protection Agency – Region 6

U.S. Department of Interior – U.S. Fish and Wildlife Service

U.S. Department of Agriculture – Natural Resource Conservation Service

U.S. Department of Commerce – NOAA National Marine Fisheries Service

State of Louisiana – Governor’s Office

The Louisiana Coastal Protection and Restoration Authority is the local cost-share partner that matches 15% of CWPPRA’s federal funding.

Wild Things Festival 2016

On October 15, the U.S. Fish and Wildlife Service hosted the 19th Annual Wild Things Festival at the Southeast Louisiana Refuge Headquarters in Lacombe, La. This exciting family-friendly event gives the community an opportunity to engage in outdoor activities while celebrating National Wildlife Refuge Week. This free public event included canoe and pontoon boat tours, hayrides, live animals, wildflower walks, kids activities, bird house building, live music, and a youth wildlife art competition.

The Coastal Wetlands Planning, Protection, and Restoration Act Public Outreach staff was among the 40 exhibitors providing hands-on activities to encourage knowledge of the Louisiana outdoors. In order to accurately portray the importance of aquatic, coastal regions, the CWPPRA staff utilized an ocean character, Sid the Restoration Squid, whose six unique legs each represented a different restoration method.  The six restoration methods include barrier island restorations, marsh creations, shoreline protection, hydrologic restoration, freshwater and sediment diversions, and terracing.  Each leg consisted of a distinct craft material that would correspond with a restoration method, in which children would assemble and personalize their own squid.  Each child’s personal squid was accompanied by an explanation guide of CWPPRA’s efforts to restore, protect, and/or create Louisiana’s wetlands.

Terracing and Marsh Creation South of Big Mar

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From 1932 to 1990, the Caernarvon Mapping Unit lost 14,240 acres of its marsh. Prior to Hurricane Katrina, the greatest loss documented occurred between 1956 and 1974 and coincided with Hurricane Betsy and extensive canal building. Hurricane Katrina devastated the area resulting in substantial marsh loss. According to USGS Open File Report (2006-1274), approximately 39 square miles of marsh around the upper and central portions of Breton Sound were converted to open water by storm related scouring or submergence of the marsh. Because the framework of the marsh has been degraded, suspended sediments provided by the diversion move through the system and fall out where velocities are reduced such as in Big Mar and Lake Lery.

The goal is to create terraces in the shallow open water areas south of Big Mar within the Caernarvon Diversion outfall area. Terraces will reduce wave fetch in the large open water areas and promote conditions conducive to growth of marsh vegetation and submerged aquatic vegetation. Additional benefits may be achieved through capturing suspended sediments. Marsh creation is also proposed to reestablish the western shoreline of Lake Lery in association with the Lake Lery Shoreline Restoration Project (BS-16).

Approximately 65,000 linear feet of terraces (37 acres) will be constructed with in-situ material to reduce fetch and turbidity and capture suspended sediment. Sediments will be hydraulically dredged from Lake Lery and pumped via pipeline to create and restore approximately 334 acres of marsh in the project area.

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The Terracing and Marsh Creation South of Big Mar project is located about 5 miles south of Violet, LA in Region 2, Breton Sound Basin in Plaquemines Parish, south of Big Mar and west of Lake Lery.

This project is on Priority Project List (PPL) 22. In 2013, BS-24 was approved for Phase I Engineering and Design.

The Terracing and Marsh Creation South of Big Mar project sponsors include:

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