Invasive Species of Wetlands

Invasive Species

Wetlands are natural ecosystems that provide an abundance of wealth to not only it’s inhabitants, but also to surrounding communities. Wetlands provide benefits ranging from water filtration to storm surge protection; however, wetlands have become vulnerable to invasive species. Invasive species are plants, animals, or pathogens that are non-native to the ecosystem and whose introduction causes or is likely to cause damage. Known as major contributors to wetland and coastal habitat loss, invasive species also threaten native species, as well as endangered species who rely exclusively on the wetlands for survival.

The foreign animals that have been recognized as invasive to coastal wetlands include Asian carp, wild boar, island applesnails, and nutria. The invasive plant species include Chinese tallow, common reed, and purple loosestrife. Invasive animal and plant species have altered the health of wetlands in some way; CWPPRA strives to protect the wetlands by constructing methods to diminish the invasive threat and restore native species dominance and health within the wetlands.


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Oyster Lake Marsh Creation and Nourishment

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The project would restore marsh to offset levels of historic and ongoing wetland loss. Based on USGS and analysis of 1978 to 2000 data and Corps of Engineers data from 1974 to 1990, land loss ranges from 4.8 acres to 18.8 acres per year from the project area. Saltwater intrusion, drought stress, and hurricane induced wetland losses have resulted in interior marsh breakup and coalescence of Oyster Lake with interior water bodies.

The primary goals of the project are to create approximately 475 acres of saline marsh in recently formed shallow open water and to nourish approximately 185 acres of saline marsh. In order to achieve these goals, sediment would be mined from the offshore disposal area used for CS-59 and placed in multiple disposal areas to create approximately 660 acres of saline marsh. Disposal areas would be constructed between the CS-59 marsh creation areas and terrace field depicted on the concept map (red polygon). Disposal would be semi-confined and up to half of the created elevations would be planted with smooth cordgrass plugs. Possible expansion of the marsh creation area is down on the concept map as yellow polygons. Although marsh creation via dedicated dredging of sediment would be the primary technique, opportunities may exist to include some terracing where warranted, but that is not included in the benefit/cost estimates at this time.

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The project is located immediately south of Calcasieu Lake and west of the Calcasieu Ship Channel in Regional Planning Unit No. 4, Calcasieu-Sabine Basin, Cameron Parish, Louisiana.

This project is on Priority Project List (PPL) 25 and was approved for Phase I Engineering and Design in January 2016.

The Oyster Lake Marsh Creation and Nourishment project sponsors include:

Keep up with the progress on CS-79 and other PPL 25 projects.

Diversity in Wetlands

Did you know:

Louisiana ranks 18th in species diversity within the United States with 3,495 species.

Species diversity includes the number of different native species in a community—also known as species richness—and the abundance of the species, referred to as species evenness. Species diversity gives a general measure of biological wealth to a given community. Louisiana harbors much of its diversity along the coast from prairies, swamps, marshes, and barrier islands. Many of our nation’s industries rely on the functionality of and species that reside within the wetlands. Furthermore, the wetlands of Louisiana are critical to protected species of lesser abundance, such as the whooping crane, piping plover, Kemp’s ridley sea turtle, and our nation’s symbol—the bald eagle.

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Shoreline Protection, Preservation, and Restoration Panel (SPPR Panel) (LA-280)

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The demonstration project would introduce an innovative solution for shoreline protection and dredge containment projects, which can be installed at a significant savings to the project owner. The demonstration project would help reduce shoreline retreat in areas that have experienced excessive amounts of erosion and would also have the intent to offset increased rates of land loss to wetlands that come exposed due to the loss of protective shoreline features through the protection of the shoreline and collection/retention of suspended sediments behind the structures.

Historically Louisiana’s coastal shoreline, bays, and lake rims have experienced high levels of retreat and land loss. The approach to repairing these areas have utilized heavy, hard engineering methods that eventually settle into the substrate,which has not achieved the goal and even presented additional hazards. Through the use of pre-fabrication of the proposed units, the landowner will see a 60%-80% reduction in installation costs when compared to typical rock rip-rap construction.

The proposed demonstration project would stabilize existing shoreline features and attenuate shoreline retreat and potentially enhance interior marshes and an accretion platform behind the structure. The goal of the proposed demonstration project is to provide a cost effective construction alternative to rip rap for shoreline protection.

The SPPR Panel is a pre-cast, saltwater tolerant concrete panel system (with no carbon steel reinforcement), the dimensions and density of which can be adjusted to site conditions. The SPPR Panel units resemble a chain when joined together allowing for on site adjustment to irregular shorelines. The project has several aspects, in that it is shoreline protection and restoration, marsh protection, restoration, and enhancement system that would deflect wave energy, protect and enhance vegetation, trap sediment, protect and create emergent marsh, and provide nursery habitat.

  1. The SPPR Panels have a variety of application possibilities that can be adjusted to best suite the problem area to best restore and enhance shorelines and marshes in many different types of coastal environments.
  2. Each panel has planned openings (vents) within the face of the unit that allows for some sediment to penetrate. The vents can be adjusted in size and location on the unit (depending on location and water depth) to allow for the most beneficial capture of available sediment.
  3. When connected, there is a 0.3′ to 0.5′ gap between SPPR Panels to allow for water drainage from behind the units, as well as, estuarine animal ingress/egress.

The demonstration project would include the selection of 2 application sites for treatment with water depths ranging from 2 to 5 feet. Each treatment would include 3 replicate 100-foot sections for a total project installation of 1,800 linear feet. Project effectiveness would be monitored and evaluated after construction according to the CWPPRA workgroups’ recommendation for the product in Phase 0. The conceptual treatment is shown in Figure 1.

By using a pre-cast SPPR Panel, owners can see significant savings from traditional rip-rap embankments by;

  • Project construction phase time is reduced
  • Reduced initial installation cost compared to rip rap embankments (60%-80% the cost of rip rap per linear foot depending upon water depths)
  • Reduced life-cycle cost compared to rip rap embankments (no additional lifts required)
  • Minimal settlement (designed for LA-16 Shark Island location which has 15′-20′ of peat…Engineering theory shows the units will only settle 6-9 inches)
  • Can be installed in water as shallow as 2-3 feet and as deep as 5 feet with minimal footprints
  • Provides fisheries access on landward side
  • Collects/retains suspended sediments

This project’s location is coastwide and is on Priority Project List (PPL) 25. This project was approved for Phase I Engineering and Design in January 2016.

The Shoreline Protection, Preservation, and Restoration Panel (SPPR Panel) project sponsors include:

Keep up with the progress on LA-280 and other PPL 25 projects.

 

 

WETshop 2016

On Tuesday, June 12th, the CWPPRA Public Outreach staff traveled to the Louisiana Department of Wildlife and Fisheries Marine Research Lab in Grand Isle, Louisiana to discuss Louisiana wetlands with teachers from around the state. The teachers participated in WETshop: a week-long, dynamic teacher workshop that allows teachers to work with educators and scientists to learn about Louisiana coastal wetlands, issues, and history. The focus of the summer workshop is to create wetland stewards of teachers in order for them to educate coworkers and students in their home parishes about coastal land loss. The workshop was sponsored by the Louisiana Department of Wildlife and Fishers and the Barataria-Terrebonne National Estuary Program. During WETshop, the teachers get a firsthand look at the importance of wetlands through visiting coastal ecosystems, water quality testing, marsh tours of coastal restoration sites, and the opportunity to learn about fisheries management, coastal botany and ornithology, and invasive species.

The Coastal Wetlands Planning, Protection, and Restoration Act’s Public Outreach staff participated in WETshop as coastal wetland educators. CWPPRA provided each of the twenty teachers with packets containing numerous publications and teaching resources, a Southeast Louisiana Land Loss Map, and posters from CWPPRA’s “Protect Our Coast” campaign. The public outreach staff also gave a presentation that highlighted causes of land loss, benefits of wetlands, CWPPRA’s history and success of projects, and different way teachers can access and utilize wetland teaching materials.

Visit CWPPRA’s Education page to access coastal teaching tools.

Wetland Marshes

Did you know:

There are four different types of wetland marshes in Louisiana.

Due to Louisiana’s proximity to the Gulf of Mexico, the exchange between fresh and salt water along the coast is frequent. Depending on the location of the marsh, it could be classified as either freshwater, intermediate, brackish, or saltwater marsh. Marshes are categorized by the salinity, or salt content, of the water, and the location of marshes to the Gulf of Mexico often directly correlates with the salinity level. Generally following a salinity gradient, freshwater marshes are commonly situated furthest inland from the gulf with a salt content of 0 ppt (parts per thousand), intermediate marshes contain a salinity range of 0-5 ppt, brackish marshes have a range of 5-15 ppt, and saltwater marshes encompass a salt content of 15 ppt or greater. Within the marsh gradient are estuaries, where fresh and salt water mix and many wetland species spend their juvenile lives.

 

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Losing Wetlands

Did you know:

Louisiana contains approximately 40% of the wetlands of the continental United States, but it experiences about 80% of its wetland losses.

Although the greatest amount of wetlands are located in Louisiana, subsidence, sea level rise, and anthropogenic activities are among the major factors contributing to the current state of Louisiana’s fragile and diminishing coastal wetlands.  Louisiana loses wetlands at an average rate of one acre per hour. If the current rate of loss is not slowed by the year 2040, an additional 800,000 acres of Louisiana’s wetlands will disappear, advancing the shoreline inward as much as 33 miles in some areas. CWPPRA is fighting to combat the speed of land loss by protecting, restoring, and creating the nation’s wetlands.

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