South Lake De Cade Freshwater Introduction (TE-39)

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The project area is experiencing marsh deterioration due to subsidence, rapid tidal exchange, and human-induced hydrologic changes that result in increased salinities. Saltwater intrusion has caused a shift in marsh type and a conversion of over 30 percent of emergent vegetation to open water habitat. Shoreline erosion along the south embankment of Lake De Cade threatens to breach the hydrologic barrier between the lake and interior marshes.

Proposed project components include installing three control structures along the south rim of the lake and enlarging Lapeyrouse Canal to allow the controlled diversion of Atchafalaya River water, nutrients, and sediments south into project area marshes. Outfall management structures are planned in the marsh interior to provide better distribution of river water. In addition, approximately 1.6 miles of foreshore rock dike is planned to protect the critical areas of the south lake shoreline from breaching.

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The project is located in Terrebonne Parish, approximately 15 miles southwest of Houma, Louisiana.

After initial engineering investigation, the project was divided into two construction units. Construction unit one consisted of the shoreline protection only and was completed in July 2011. Construction unit two consisting of the freshwater introduction component was further investigated and due to uncertainty of benefits was not constructed, and therefore, the project is considered completed.

This project is on Priority Project List 9.

The Federal Sponsor is NRCS

The Local Sponsor is CPRA

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Regional Planning Teams

This week, CWPPRA was scheduled to hear proposals for potential projects that will compete for funding in the upcoming fiscal year. FY19 is bound to have some fierce competitors, including some projects that may not have been awarded funding in previous years. In our Dec 12, 2018 post, we outlined a bit of the project selection process and we hope to see new and innovative ideas soon. At this time, the Regional Planning Team (RPT) meetings have been postponed following the government shutdown.

To reiterate the RPT process from the December 12th post, new projects are proposed annually across the coast. If any of our readers wish to propose a project this year, watch our newsflash for rescheduled meeting times in your region. Project proposals guidelines can be found on our Newsflash announcement. After each RPT meeting, the projects from each of CWPPRA’s 4 regions are compiled by RPT members and submitted to the next phase of competition. Each Parish and CWPPRA personnel submit a ranking of important projects, which helps the Technical Committee narrow down the list to 10 of the most promising projects. These 10 projects are further evaluated by CWPPRA working groups to look at environmental impact, engineering concepts, and other important aspects of each proposal, then the Technical Committee selects 4 to recommend to the Task Force for Phase I Engineering & Design.

In December 2018, the CWPPRA Technical Committee narrowed 10 potential Phase I projects down to 4 and the list for Phase II approval to 2 projects. The Task Force was scheduled to meet January 24th, 2019 to approve the recommended projects but, since the federal government was still partially closed, some of the critical task force representatives were unable to meet that day and so that meeting will be replaced with an electronic vote.

This latest government shutdown may have thrown a wrench into the CWPPRA process, our commitment to the coast is as strong as ever. We will continue to hear proposals, select projects, and work with our partners to construct projects that support the state of our coastline and all who live there. Watch for our Newsflash if you want to participate in our Project selection process; we look forward to helping you #ProtectOurCoast!

 

Featured image from https://www.nytimes.com/slideshow/2016/05/03/science/isle-de-jean-charles-resettlement-plan.html

Planning for Coastal Changes Together

The Louisiana Coastal Master Plan strategically plans restoration and risk reduction projects for the current and future Louisiana coast. This state-wide plan is updated every 6-years and focuses on a 50-year view which “coordinates Louisiana’s local, state, and federal responses to land loss, and potential threats from hurricanes and storm surge events” [2]. The Master Plan was developed by the Coastal Protection and Restoration Authority (CPRA) and models scientific data through different scenarios to determine which projects have priority. CPRA represents the State of Louisiana and contributes 15% of costs for Coastal Wetland Planning, Protection, and Restoration Act (CWPPRA) projects. Since all CWPPRA projects are partially funded by the state of Louisiana, then all CWPPRA projects must be consistent with the Coastal Master Plan.

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The Louisiana Coastal Master Plan is an example for communities around the world who are facing coastal land loss at home. For example there is a recent partnership agreement between the Dutch research institute Deltares and the  Water Institute of the Gulf in Baton Rouge. Therefore both institutions can benefit and contribute to the planning being done to preserve Louisiana coastal wetlands. Other areas facing coastal land loss, like Singapore, Indonesia, and Canada also have an interest in the work being done in Louisiana and the Netherlands [1]. By working together, communities in Louisiana and elsewhere can adapt to and protect changing coasts.

Click here to learn more about Louisiana’s Coastal Master Plan.

Click here to learn about your flood zone in Louisiana.

Sources:

[1] Roberts, Faimon. Louisiana institute, Dutch research group launch partnership to study water issues. Available: https://www.theadvocate.com/baton_rouge/news/environment/article_35247102-635a-11e7-9176-9f60e4fab282.html [July 31, 2018].

[2] The Louisiana Coastal Master Plan. Available:http://coastal.la.gov/wp-content/uploads/2017/04/2017-Coastal-Master-Plan_Web-Book_CFinal-with-Effective-Date-06092017.pdf [July 31, 2018].

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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West Belle Pass Barrier Headland Restoration (TE-52)

wordpress fact sheet banner TE-52-01.pngThis headland experiences some of the highest shoreline retreat rates in the nation, measuring over 100 feet a year in some locations. As the gulf encroaches upon the shoreline, sand is removed and the headland erodes. What was once a continuous shoreline spanning several miles has been reduced to less than half its original length. Furthermore, Hurricanes Katrina and Rita removed most of the emergent headland and dunes west of the pass. This headland helps provide protection to interior marshes and the Port Fourchon area; however, its continued degradation threatens the fragile bay habitat and infrastructure it once protected.

This project will reestablish the West Belle headland by rebuilding a large portion of the beach, dune, and back barrier marsh that once existed. Approximately 9,800 feet of beach and dune will be rebuilt using nearly 2.8 million cubic yards of dredged sand, and 150 acres of marsh habitat will be rebuilt using nearly 1.4 million cubic yards of dredged material. Native vegetation will be planted upon construction to help stabilize the rebuilt marsh and dune habitat.

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The project is located along the Chenier Caminada headland to the west of West Belle Pass, at the southeastern edge of Timbalier Bay in Lafourche Parish, Lousiana.

This project was approved for engineering and design in October 2006. Construction funds were approved by the Task Force in late 2009, construction began fall 2011, and construction was completed in October 2012.

This project is on Priority Project List 16.

Federal Sponsor: NOAA NMFS

Local Sponsor: CPRA

Beneficial Use of Dredged Materials

Neither time nor sediment should go to waste! CWPPRA and our partners believe that beneficial use of dredged material in projects is an important part of coastal wetlands restoration.

Beneficial use, in simple terms, is the act of using dredged materials to fortify our barrier islands, build marsh platforms, or nourish the coastline instead of disposing it into places that will not benefit from it. Dredging is necessary to keep important transportation channels open for commercial ships and recreational boating. When dredging a canal, sediment is often dumped in holding facilities or off the continental shelf because of the low price tag. Borrowing sediment from otherwise untouched and stable areas is not necessary when dredging already makes viable material readily available.  [1]

Many CWPPRA projects that are approved for construction have implemented beneficial use of sediment. For example:

  • BA-39 Mississippi River Sediment Delivery – Bayou Dupont
  • MR-08 Beneficial Use of Hopper Dredged Material Demonstration
  • AT-02 Atchafalaya Sediment Delivery
  • TE-44 North Lake Mechant Landbridge Restoration
  • CS-28 Sabine Refuge Marsh Creation (Cycle II and onwards)
  • And many more!

Of course, some areas will not be in close enough proximity to a channel with reliable dredging, but we want to maximize beneficial use when and where possible. For CS-28-2, our partners installed a permanent dredged material pipeline to further decrease damage to coastal wetlands that temporary pipelines can cause. The permanent pipeline ensures that whenever the Calcasieu River Ship Channel needs dredging, the dredged material goes to restoring wetlands with as little detrimental influence as possible.

Sediment is a valuable resource for coastal Louisiana, and the need for sediment across the coast means that we can’t afford to waste any. CWPPRA projects strive to use sediment from as many sources as possible so that more projects have the material they need- with some creativity, a little sediment can go a long way.

 

Featured image from https://www.theadvocate.com/acadiana/news/article_5f227419-6c44-5a0d-a641-1af377e5bb91.html

[1] https://www.epa.gov/cwa-404/beneficial-use-dredged-material

Marsh Island Hydrologic Restoration (TV-14)

banner_tv-14.fwReasons to Restore:

  • Natural erosion
  • Subsidence
  • Construction of navigation canals along the northeast shoreline of a Marsh Island.
  • Deterioration of the north rim of Lake Sand and the interior marshes.

Restoration Strategy:

  • Stabilizes the northeastern shoreline of Marsh Island.
  • Stabilizing the northern shoreline of Lake Sand.
  • Help restore the historic hydrology.
  • Construction of 7 closures for oil and gas canals at the northeast end of Marsh Island.
  • Protect the northeast shoreline with rock including the isolation of Lake Sand from Vermilion Bay.

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[2]

Location:

This project is located in Iberia Parish, Louisiana, on the eastern portion of the Russell Sage Foundation Marsh Island State Wildlife Refuge and surrounding Lake Sand.

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Project Effectiveness [1]:

  • Effective at reducing water level variability within the northern portion of the project area
  • Water level variability did not increase in the project area as is did in R1 post-construction
  • Reducing erosion rates at the northeast shoreline was partially met
  • Reduced erosion in areas of applied rock dikes versus unprotected areas.
  • The steel sheet pile, rock rip-rap wingwall, and stone bank paving installed at each end of closure No. 5 proved to be successful in preventing erosion during a storm event.

Previous Progress [2]:

  • The monitoring plan was finalized in January 2000 following with further data collection.
  • Pre-construction and post-construction aerial photography were in the year 2000, and 2009 with future imagery analyses upcoming.
  • Water level, submerged aquatic vegetation and shoreline position and movement data were also collected to evaluate project effectiveness.

Progress to Date [1]:

  • Construction was completed in December 2001.
  • This is one of the three projects nearing the end of their 20 year lives.
  • The Task Force will vote on the Technical Committee’s recommendation on the path forward for the following projects [1]:

3 projects

This project is on Priority Project List (PPL) 6.

Project Sponsors Include:

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Source:

[1] Mouledous, M. and Broussard, D. 2014. 2014 Operations, Maintenance, and Monitoring Report for Marsh Island Hydrologic Restoration. Coastal Protection and Restoration Authority (CPRA). Available:https://lacoast.gov/ocmc/MailContent.aspx?ID=10092 [May 22,2018].

[2] Marsh Island Hydrologic Restoration (TV-14) Land-Water Classification. 2009. Coastal Wetlands Planning, Protection, and Restoration Act (CWPPRA). Available: https://www.lacoast.gov/products/sab_net_pub_products/map/original/2011-02-0009.pdf [May 22, 2018].