New Orleans Landbridge Shoreline Stabilization & Marsh Creation (PO-169)

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Since 1956, approximately 110 acres of marsh has been lost along
the east shore of Lake Pontchartrain between Hospital Road and
the Greens Ditch. One of the greatest influences of marsh loss in
the area can be attributed to tropical storm impacts. Wetland losses
were accelerated by winds and storm surge caused by Hurricane
Katrina, which converted approximately 70 acres of interior marsh
to open water. Stabilizing the shoreline and protecting the
remaining marsh would protect natural coastal resources dependent
on this important estuarine lake, communities that thrive on those
resources, the Fort Pike State Historical Site, and infrastructure
including U.S. Highway 90. USGS land change analysis
determined a loss rate of -0.35% per year for the 1984 -2011
period of analysis. Subsidence in this unit is relatively low and is
estimated at 0-1foot/century (Coast 2050).

Lake Pontchartrain supports a large number of wintering
waterfowl. Various gulls, terns, herons, egrets, and rails can be
found using habitats associated with Lake Pontchartrain, which has
been designated as an Important Bird Area by the American Bird
Conservancy. Restoring these marshes will protect the Orleans
Landbridge and will help to protect fish and wildlife trust resources
dependent on these marsh habitats, particularly at-risk species and
species of conservation concern such as the black rail, reddish
egret, brown pelican, mottled duck, seaside sparrow, king rail, and
the Louisiana eyed silkmoth.

Borrow material will be dredged from areas within Lakes St.
Catherine and Pontchartrain to create 169 acres and nourish 102
acres of brackish marsh. Containment dikes will be constructed
around four marsh creation areas to retain sediment during
pumping. The lake shorelines will be enhanced with an earthen
berm to add additional protection from wind induced wave fetch.
Containment dikes that are not functioning as shoreline
enhancement will be degraded and/or gapped. Vegetative plantings are
proposed including five rows along the crown and two rows
along the front slope of the shoreline protection berm, as well as
within the marsh platform area.

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The project is located in Region 1, Pontchartrain Basin,
Orleans Parish, flanking U.S. Highway 90 along the east shore of
Lake Pontchartrain and areas surrounding Lake St. Catherine.

This project was approved for Phase I Engineering and Design in
January 2015.

This project is on Priority Project List (PPL) 24.

The New Orleans Landbridge Shoreline Stabilization & Marsh Creation sponsors include:

 

 

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Mangroves in Winter

The recent cold weather in Louisiana may have been the end of the road for some plants as temperatures dipped into the teens and stayed below freezing for full days. The hibiscus in your garden may have survived because you gave it extra insulation, but what about marsh plants? Louisiana salt marshes are home to black mangroves (Avicennia germinans), but this represents the very northernmost part of their range. Of the three mangrove species found in the continental United States [red (Rhizophora mangle), black, and white (Laguncularia racemosa)], black mangroves are the most cold-hardy, but they are still sensitive to winter weather- they generally cannot establish above 28° N and S latitude because winters are too cold (a sliver of the Birdsfoot Delta is below 29° N, so we really are at their limit).

The three mangrove species are also different in their tolerances for other environmental conditions: red mangroves establish in the intertidal zone, while black and white mangroves are found at higher elevations, and white mangroves can colonize areas with little to no soil. In Florida where all three species occur, mangrove zones can be defined from the water extending inland and up in elevation .

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Red mangroves are found in the intertidal zone, while black and white mangroves establish at higher elevations. Graphic from the Florida Museum of Natural History at the University of Florida (https://www.floridamuseum.ufl.edu/southflorida/habitats/mangroves/zonation/)

Black mangroves are an important component of Louisiana salt marshes, providing habitat to a variety of species. The complex root systems trap and collect sediment, limiting erosion and maintaining land. Juvenile invertebrates and fish find shelter among the roots, while seabird chicks, such as brown pelicans and roseate spoonbills, are protected from high water events and predators up in the branches.

CWPPRA projects that nourish barrier islands and create new marsh habitat help maintain black mangrove populations by providing new land for the plants to colonize; in turn, the mangroves help the new land persist in the face of wind and wave energy.

Wetlands and Waterfowl

At this time of year in Louisiana, you are sure to see early morning waterfowl hunters dressed in their best camouflage. Louisiana sits on the Mississippi Flyway, North America’s most heavily-used migration corridor for waterfowl. Louisiana’s coastal wetlands provide habitat for more than five million migratory waterfowl, approximately half of the wintering duck population of the Mississippi Flyway. The coastal marshes of Louisiana provide habitat to mottled ducks, wood ducks, redheads, and pintails, just to name a few species. These waterfowl species can be spotted in coastal marshes, flooded timbers, flooded grain fields, and other wetland areas. Grab your waders, shot gun, and a duck call, and take advantage of Louisiana’s Sportsman’s Paradise.

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It is critical to protect the coastal marshes and wetlands within the state for Louisiana to remain the front runner for waterfowl hunting. CWPPRA projects are aimed at protecting and restoring Louisiana’s coastal wetlands, ensuring that wildlife and the people who hunt them have the habitat they need.

The Bald Cypress

In 1963, the Bald Cypress (Taxodium distichum) was designated as Louisiana’s official state tree. The bald cypress’s deciduous character, unlike most conifers gives, it a “bald” appearance. This type of tree is rather majestic and can be spotted in the swamps of Louisiana. It has a swollen, ridged trunk at the base; widespread branches; reddish-brown bark; and roots that often cause what we know as cypress knees to appear around the tree. Although the bald cypress is widely adaptable, it prefers to grow in wet, swampy soils. Riverbanks, floodplains, and wet depressions are specific areas in which the bald cypress thrives.

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Bald cypresses provide habitat benefits to terrestrial and aquatic wildlife. The Louisiana forestry industry is also dependent on these cypress trees to contribute to a productive annual harvest with large monetary returns on the lumber and cypress mulch produced. The Atchafalaya Basin makes up a large share of the coastal wetlands, and more the half of the acreage of the Atchafalaya basin is cypress wetland forest. The bald cypresses of the wetlands are important to Louisiana’s culture, animal habitats, and the economy. Maintaining healthy cypress wetlands is critical to maintaining a natural storm buffer, filtering polluted water, providing irreplaceable habitats, and sustaining a thriving economy.

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National Wildlife Refuge

The National Wildlife Refuge System includes public lands and waters that are set aside to conserve America’s wildlife and vegetation. The protected areas of the National Wildlife Refuge are managed by the United States Fish and Wildlife Service. Since initiation in the early 1900s, the system has grown immensely to over 500 National Wildlife Refuges.

A variety of habitats are managed by the National Wildlife Refuges, including wetlands, prairies, coastal and marine areas just to name a few.  Conserving the threatened or endangered species of these habitats is a primary focus of the National Wildlife Refuge System. Employees must manage the refuge by controlling invasive species, securing adequate water resources, and assessing external threats to the protected area.

If you’re interested in outdoor recreational activities like hunting, birding, fishing or even environmental education, National Wildlife Refuges welcome guests to participate in the year-round fun that can be found at a refuge in any of the fifty states. You can find a National Wildlife Refuge you would like to visit by clicking here.

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Visit the U.S. Fish and Wildlife Service website to read more information and updates about the National Wildlife Refuge System.

LaBranche East Marsh Creation

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Dredging of access and flotation canals for the construction
of I-10 and the Illinois Central Railroad resulted in increased
salinity and altered hydrology in the area that exacerbated
the conversion of wetland vegetation into shallow open
water bodies.

The project’s primary goal is to restore marsh that has been
converted to open water. Project implementation will result
in an increase of wildlife and fisheries habitat, acreage and
diversity, along with improving water quality. In addition,
the project will provide a storm buffer protection to I-10, the
region’s primary westward hurricane evacuation route, and
complement hurricane protection measures in the area.
Project features consist of the creation of 729 acres of marsh
and the nourishment of 202 acres of existing marsh using
dedicated dredging from Lake Pontchartrain. In addition,
10,000 linear feet of tidal creeks will be created. The marsh
creation area will have a target elevation the same as average
healthy marsh for this region. Plans are to place the dredge
material in the target area with the use of low level, noncontinuous
retention dikes along the edge of the project area
allowing overtopping of material to nourish the marsh fringe.
Vegetative plantings will be utilized in the areas deemed
most critical by the project team. Successful wetland
restoration in the immediate area (PO-17) clearly
demonstrates the suitability and stability of soil and material
availability from a sustainable borrow area.

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The project features are located between Lake Pontchartrain
and I-10 in St. Charles Parish, Louisiana. It is bounded on
the west by the Fall Canal and the Bayou LaBranche
Wetland Creation Project (PO-17) and the east by a pipeline
canal.

This project is on Project Priority List (PPL) 19.

The LaBranche East Marsh Creation project sponsors include:

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

 

Frogs in Wetlands

Frogs are a distinct part of the wildlife we find within wetlands. When wetlands begin to flood either from rainfall or river flow, the volume of croaking increases and breeding begins to take place. Frogs more than any other terrestrial animal need water for survival, and their breeding is tied to when flooding of the wetland occurs.

Even though water is the primary factor driving frog distributions, food availability, aquatic vegetation, and predator densities are other factors that contribute. Wetland vegetation provides shelter for adult frogs. Spanish moss is popular wetland vegetation used by frogs to hide from predators. While vegetation provides shelter for adult frogs, it also serves as a platform for biofilms and organic matter to grow, which are important food sources for tadpoles. The thin, porous skin of frogs and tadpoles also makes them great bio indicators. They are very sensitive to environmental damage because of the chemicals their skin absorbs from the air and water. If an area is populated by frogs, it means the local environment is likely to be pristine.