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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)

 

 

Featured

Classifying Wetlands Part 2

Last week’s Wetland Wednesday mentioned 3 main criteria as part of identifying a wetland (wetland hydrology, hydrophytic vegetation, and hydric soils). – Today we’ll look at how plants and soils help scientists delineate wetlands.

In the field, scientists identify and sample soils and plants as part of wetland delineation. The LSU AgCenter groups plant species based on where the plant is naturally found as seen in the table below.

indicator_2Wetland plants have adapted to flooded soils. “Obligate” plants can tolerate water at high levels or when soil saturation is a normal condition to that area. Examples of these plants include the bald cypress (Taxodium distichum), or cattail (Typha latifolia) [3].

In contrast, plants that cannot handle flooded conditions for an extended period would naturally be in the “upland” area of land (i.e. winged sumac (Rhus copallina), eastern redbud (Cercis canadensis), or panic grass (Dichanthelium sp.) [3].

People delineating wetlands focus on a project area according to aerial and soil maps along with aerial photographs [1]. Delineators then take soil samples and determine characteristics seen in hydric soils which relate to cycles of flooding and drying. – Examples of those include oxidized soils, hydrogen sulfide (rotten egg smell) and organic bodies found on plant roots. Finally, the plant and soil types are compared, tested, then matched to determine wetland boundaries for mapping and policy purposes [1].

Wetland delineation is a tool for protecting and documenting these important landscapes which contribute to a healthy and functional environment. It is important to note that wetland delineation requires much more than just plant and soil identification. CWPPRA utilizes sound science, engineering, mapping, and geo-technical surveys in the process of planning, approving, constructing, and maintaining coastal Louisiana wetland restoration projects.

Sources:

[1] Bedhun, Rebecca. 2018. “Watch and Lean Now: How To Do A Wetland Delineation”. Shoret Elliot Hendrickson Inc. Available: http://www.sehinc.com/news/watch-and-learn-now-how-do-wetland-delineation [September 9, 2018]

[2] Jon Kusler. “Common Questions: Wetland Definition, Delineation, and Mapping”. Association of State Wetland Managers, Inc. Available: https://www.aswm.org/pdf_lib/14_mapping_6_26_06.pdf [September 9, 2018]

[3] LSU Ag Center. 2018. Louisiana Plant Identification: Plant List. Available: http://www.rnr.lsu.edu/plantid/listcommon.htm [September 10, 2018]

 

Featured

Classifying Wetlands Part 1

When we think of wetlands, our mind may paint a picture of a swampy area with open water, and maybe a heron or alligator. Despite common perception, not all wetlands are the same. — These watery features come in all shapes, sizes, and locations along with a unique system of processes and purpose.

Wetlands are diverse and the difference between dry and wet environment lies along a gradient. Therfore, there cannot be one perfect definition to represent what a wetland is. Scientists have developed criteria to identify wetlands and aid in assessment, inventory, and management [1].

Figure 1. An example used by scientists to start the process for wetland delineation.

Criteria Definition
Wetland hydrology the gradient or degree of flooding or soil saturation across a landscape [2].
Hydrophytic vegetation plants adapted to grow in water or in a soil that is occasionally oxygen deficient due to saturation by water [2].
Hydric soils soils that are sufficiently wet in the upper root zone  and may develop anaerobic (oxygen lacking) conditions during the length of at least 1-2 growing seasons [2].

As seen below in Figure 2 and 3; some wetlands are flooded year-round while other  water levels fluctuate. The wetland hydrology differs depending on location and the geography of the landscape.

Figure 2: A simplified example of a wetland water gradient dependent on elevation and tidal ranges.

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Figure 3.

basic_gradientYou may not live close to a coastal marsh, but many water sources eventually connect to a wetland on the coast, making the streams, lakes, and swamps in your backyard an important link to the larger watershed. That’s why it’s important to support, respect, and appreciate the water systems and land of everyday life. CWPPRA projects restore and protect these systems to support the livelihood and cultures of Louisiana and to protect the land we value so dearly.

In next week’s edition of Wetland Wednesday, we’ll look at how scientist use vegetation and soils to classify wetlands!

 

Source:
[1] Fish and Wildlife Service. Classification of Wetlands and Deepwater Habitats of the United States. Available: https://www.fws.gov/wetlands/documents/Classification-of-Wetlands-and-Deepwater-Habitats-of-the-United-States-2013.pdf [August 27, 2018].
[2] Natural Resources Conservation Service. Hydric Soils Overview. Available: https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/use/hydric/?cid=nrcs142p2_053985 [August 27, 2018].
Featured

Hurricanes

This week marks 13 years since Hurricane Katrina, an event some citizens of Louisiana are still recovering from. We may have all heard the name, but do we know what a hurricane is, how wetlands are affected, and how coastal landforms can decrease hurricane impacts?

“Hurricanes” are low-pressure tropical storm systems that differ from other storms in severity as well as location. A hurricane is a storm with winds above 64mph accompanied by heavy rain that originates in either the NE Pacific or the N Atlantic Ocean (the oceans that touch the USA). Due to a phenomenon called the Coriolis Effect, hurricanes rotate counter-clockwise, whereas a southern hemisphere storm would rotate clockwise. Hurricanes develop a characteristic “eye of the storm” in the center, which is an area of low pressure and low wind. Just outside of the eye is the most severe weather, the eyewall, with winds reaching up to 210mph in the strongest storms! Hurricane “category” ratings are as follows:

  • Category 1: 74-93mph
  • Category 2: 96-109mph
  • Category 3: 110-129mph
  • Category 4: 130-157mph
  • Category 5: >158mph

Hurricanes develop over areas with warmer waters, typically nearer the equator, and move away from the equator. [1] Coastal Louisiana is hit by hurricanes on an increasingly regular basis, and those hurricanes all develop in the North Atlantic Ocean in late summer and fall. Our “Hurricane Season” occurs from June through November each year. [2] Several aspects of hurricanes pose major threats to our wetlands statewide. High winds can topple trees, rip up shrubs and grasses, and move sediments around. High rainfall can cause flooding in areas that are not well-adapted to high-water conditions. Storm surge can push saline seawater into brackish and freshwater systems. Hurricanes cause massive disturbance in coastal wetlands, but wetlands are a crucial barrier that protects major cities from taking as much damage. CWPPRA works to combat land loss and protect the future of coastal Louisiana.

Some CWPPRA projects restore barrier islands, which are natural defenses that develop in the Deltaic Cycle. Barrier islands lessen storm surge during hurricanes, bearing the brunt of the waves. Sadly, they cannot provide perfect protection because they are degrading, but they are not the last line of defense. We still have coastal marshes that are great at storing water and acting like a speed bump to storm surge. It is estimated that each mile of coastal marsh decreases storm surge by about a foot. Unfortunately, many coastal marshes are decaying into open water and are no longer protective barriers. CWPPRA will continue to restore wetlands and nourish barrier islands to #ProtectOurCoast!

 

[1] https://en.wikipedia.org/wiki/Tropical_cyclone

[2] https://www.ready.gov/hurricanes

Featured image from [1]

Thankful for Wetlands

When celebrating Thanksgiving tomorrow, be sure to think about all of the ways wetlands provide for you and yours. Whether you enjoy the serene experience of watching a sunset through bald cypress trees, catching redfish in the marsh with your family, or simply love a good shrimp po-boy, Louisiana wetlands provide a huge number of services to millions of people daily.

In addition to protecting our cities from storm surge, wetlands of all kinds host tremendous species diversity, are highly productive, and allow for many types of recreation. Louisiana provides seafood nationwide. All of our most profitable species use wetlands for some part of their life cycle. [1] For example, shrimp spawn in estuaries, crawfish spend their whole semi-aquatic lives in freshwater wetlands, and oysters occupy coastlines while providing some wave attenuation and water filtration. CWPPRA and our partners see oysters as an alternative method to protect our some parts of our coast with artificial reefs that can also be harvested, making them a highly sustainable food source. Some foods we receive from wetlands aside from seafood include turtles and ducks in some cases, rice (a staple in many cultures worldwide), and a wide array of other plants for their tubers or berries.

Beyond the food, though, wetland benefits include flood protection to our major cultural hubs and carbon sequestration. Sequestering carbon makes wetlands wildly productive and an ally in the fight against global climate change. [2] CWPPRA was written into law in 1990 to help preserve these bountiful ecosystems so they can continue to thrive and benefit people in Louisiana and beyond. This holiday season, even if you are not eating any seafood during your feasts, you are benefitting from wetlands, so say a thank you for all of those natural areas that give us so much.

[1] https://www.epa.gov/sites/production/files/2016-02/documents/economicbenefits.pdf

[2] https://imedea.uib-csic.es/master/cambioglobal/Modulo_V_cod101611/Coastal%20sinks%20(seagrasses_mangroves_saltmarshes)/Bibliography_coastal/Chmura%20et%20al%202006.pdf

 

America Recycles And So Do We

Recycling is a great practice at home, but it reaches far beyond taking materials out of the waste stream. Tomorrow, November 15th, is designated as America Recycles Day, so today’s Wetland Wednesday is hopeful about the future of sustainability.

New materials require exploration and processing that can be destructive to ecosystems. Plastics, some of the most common materials in the product stream today, are largely recyclable. As a crude oil byproduct, producing new usable plastics requires a lot of energy. The same goes for many other recyclable materials. Paper products, various metals, and glass all take a lot of energy to produce, then they quickly find their way into landfills instead of being reused. Landfills produce a wide array of chemicals that often leach into the ground due to poor containment practices, and they can contaminate watersheds. Once those chemicals get into a watershed, they can significantly decrease the health of wetlands across huge swaths of land over time. To further the polluting effects, drilling for oil to meet a growing desire for fossil fuels is one of the most detrimental practices to wetlands. More than 5 years after the Deepwater Horizon oil spill in the Gulf of Mexico, Louisiana wetlands continued to lose ground due to the spill’s impact. [1]

Recycling is not a perfect alternative to single-use plastics, and there are other ways to reduce our consumption of resources. For example, mitigating loss of byproducts by finding new and inventive applications can greatly reduce consequences. Large-scale food manufacturing leaves plenty of byproduct as leftover plant material that can be used as livestock feed, potentially as biofuels, or fertilizer. In the meat industry, byproducts are often further processed and commercialized to maximize the use of all parts of animals. CWPPRA and our partners have changed some practices in recent years to be more efficient when using resources, for example beneficial use of dredged material (yes, we recycled our header image). Mandatory dredging of shipping and navigational channels produces a bounty of sediment that was lost in the past, but we can now use that material in restoration projects. This exciting new practice has already been implemented in a few CWPPRA projects to restore marshland and nourish pre-existing wetlands.

Our coast faces many human-caused threats, and its future depends, in part, on practices becoming more sustainable. By using new technologies to better use resources, CWPPRA hopes that Louisiana’s natural splendor and resilience can continue to benefit future generations.

[1] https://pubs.er.usgs.gov/publication/70178409

 

Whiskey Island Back Barrier Marsh Creation (TE-50)

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Gulfside and bayside erosion has resulted in the narrowing of Whiskey Island (and the entire Isles Dernieres chain) as the two shorelines migrate toward each other, resulting in a 68 percent decrease in average width for the Isles Dernieres. Within 100 years, the entire subaerial portion of the Isles Dernieres barrier island system is expected to disappear except for small land fragments associated with the western end of Whiskey Island and the eastern end of East Island. However, some estimates project the Isles Dernieres will disappear much earlier. Other predictions suggest that, without restoration, Whiskey Island could become a subaqueous sand shoal by 2019. Another CWPPRA restoration project, Whiskey Island Restoration (TE-27), which included placement of dredge material, vegetative planting, and sand fencing, was completed in 2000.

The goal of the TE-50 project is to increase the longevity of the previously restored and natural portions of the island by increasing the island’s width. Increasing the island’s width will help to retain sand volume and elevation. Approximately 319 acres of back barrier intertidal marsh habitat, 5,865 linear feet of tidal creeks, three 1-acre tidal ponds and 13,000 linear feet of protective sand dune were created by semiconfined disposal and placement of dredged material. The sediment was dredged from a sediment source in the Gulf of Mexico near the island. The area was planted with native marsh vegetation to colonize and protect the newly-placed marsh soil.

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Whiskey Island, one of five islands that make up the Isles Dernieres barrier island chain, is located 18 miles southwest of Cocodrie in Terrebonne Parish, Louisiana. The island is surrounded by Coupe Colin to the west, Whiskey Pass to the east, Lake Pelto, Caillou Boca, and Caillou Bay to the north, and the Gulf of Mexico to the south.

The CWPPRA Task Force approved funding for construction (phase 2) at the February 13, 2008 Task Force meeting. Construction began in March 2009 and initial construction was completed in November 2009.Vegetative plantings were installed at the project site in June of 2010 and October 2011.

This project is on Project Priority List 13.

Federal Sponsor: EPA

Local Sponsor: CPRA

Living Shorelines

According to NOAA, one of our managing agencies, a living shoreline is “A protected and stabilized shoreline that is made of natural materials such as plants, sand, or rock.” [1] In some situations, living shorelines are a better option than hardened shoreline protection because they have more movement of natural sediment, the ability to grow, and the obvious aesthetic value of a natural area.

‘Living shorelines’ can refer to multiple restoration techniques and coastal environments; for CWPPRA, a living shoreline can mean vegetative planting on a marsh creation cell or using a shoreline protection barrier that promotes oyster reef growth. Living restored shorelines help maintain the integrity of ecosystems, but they also provide benefits to recreation and potentially to commerce. One big push in restoration over the past few years has been artificial oyster reefs which provide wave attenuation, natural water filtration, and a harvestable population of oysters for the seafood industry. [2]

Illustration, Courtesy of NOAA [1]
Vegetated marsh provides similar benefits to artificial oyster reefs and is a tried-and-true restoration strategy. Many marsh creation projects will naturally revegetate thanks to seed banks in borrow sites but some need management to limit invasive species. In more vulnerable sites, CWPPRA actively plants native species like smooth cordgrass and California bulrush to give them an advantage against invasive populations.

CWPPRA understands that successful restoration projects, including shoreline protection, help keep ecosystems intact and productive. A changing coast means we need changing solutions, and we will strive to find better alternatives to maintain the natural environment.

[1] https://oceanservice.noaa.gov/facts/living-shoreline.html

[2] https://www.smithsonianmag.com/innovation/storms-get-bigger-oyster-reefs-can-help-protect-shorelines-180967774/

Featured image from https://oceanbites.org/oyster_reef_restoration/

 

Louisiana’s Live Oak Cheniers

With coastal needs continuing to grow, we can learn from nature’s history for ways to strengthen our coastlines. While we often think about how barrier islands protect the coast from storms, coastal cheniers and forests across Louisiana are also essential in providing that protection. These coastal forests are often found on shell ridges known as cheniers.

French for “place of oaks”, cheniers act as storm barriers, prevent saltwater intrusion, and provide wildlife habitat for migratory birds and butterflies [1,3]. Cheniers along  Louisiana’s coast extend from Cameron Parish in the west to Iberia Parish” [1]. Due to their higher relief, or height above sea level, a large majority of these areas were cleared for human development uses such as highways, agriculture, and oil and gas [2]. Louisiana originally hosted 100,000 to 500,000 acres of chenier, but today only 2,000 to 10,000 acres remain [1].

While these numbers can be discouraging, local and state efforts are in place to conserve live-oak (Quercus virginiana) cheniers and coastal forests.

Louisiana is fortunate to have programs and organizations like this to conserve the coast and its natural abundance. These practices along with landowner, volunteer and citizen engagement are essential to coastal restoration. You may visit CWPPRA’s website lacoast.gov to learn how you can help Louisiana’s coastal wetlands!

Do your part to conserve our environment and help Louisiana’s coast!

Source:
[1] Louisiana Comprehensive Wildlife Conservation Strategy. Date Accessed October 30, 2018. Available:http://www.wlf.louisiana.gov/sites/default/files/pdf/document/32867-coastal-live-oak-hackberry-forest/coastal_live_oak-hackberry_forest.pdf
[2] Army Corps of Engineers. Southwest Coastal Louisiana Final Integrated Draft and Feasibility Report and Environmental Impact Statement. Date Accessed October 30, 2018. Available:http://www.mvn.usace.army.mil/Portals/56/docs/PD/Projects/SWCoastal/11%20Appendix%20A%20Env%20Report.pdf
[3] Baton Rouge Audubon Society. Accessed on 10/31/2018. Available:http://www.braudubon.org/peveto-woods-sanctuary.php

Ocean Commotion 2018

The 21st annual Ocean Commotion event was held at LSU on October 25, 2018. Sponsored by the Louisiana Sea Grant, Ocean Commotion is an opportunity to learn about coastal and oceanic issues. Held at the LSU Pete Maravich Assembly Center, 65 exhibitors provided hands-on learning about Louisiana’s coastal environment, sustainability practices, our beloved oceans, and the organisms that live here. More than 1,800 students, teachers, and chaperones from area schools had the opportunity to look at zooplankton with the LSU Department of Oceanography, build a delta with LSU Sea Grant, and come face to face with animals from Bluebonnet Swamp.

CWPPRA Outreach staff were set up with our Mysterious Wetland Wonders. Students read clues and then reached inside boxes (no peeking!) to identify plant and animal relics. From invasive apple snail shells to magnolia seed pods to a turtle carapace, each item can be found in Louisiana wetlands. Our wetlands are home to a diverse array of plants and wildlife and provide us with recreation, economic benefits, cleaner water, and other ecosystem services. Protecting these wetlands helps protect all of the groups that depend on them for food, shelter, and fun.

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CWPPRA Outreach staff were set up with our Mysterious Wetland Wonders. Students read clues and then reached inside boxes (no peeking!) to identify plant and animal relics. From invasive apple snail shells to magnolia seed pods to a turtle carapace, each item can be found in Louisiana wetlands. Our wetlands are home to a diverse array of plants and wildlife and provide us with recreation, economic benefits, cleaner water, and other ecosystem services. Protecting these wetlands helps protect all of the groups that depend on them for food, shelter, and fun.

East Sabine Lake Hydrologic Restoration (CS-32)

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The lower salinity marshes are converting to shallow, open water due to elevated salinity events and subsidence. Navigation channels provide a direct route for salt water to infiltrate the marsh, disrupt the natural water circulation, and allow rapid runoff of fresh water. The larger Sabine-Neches Waterway and the Gulf Intracoastal Waterway (GIWW) have allowed saltwater intrusion into the project area’s fresh and intermediate marshes. Elevated tidal fluctuations in these channels have led to increased water flow, which has increased the conversion of marsh to open water. Area marsh loss is also caused by wave action along Sabine Lake and interior marsh shorelines and other natural causes (i.e., subsidence).

The project features include: a rock weir in Pines Ridge Bayou; three culverts with flap gates at Bridge Bayou; a 3,000 foot-long rock rip-rap breakwater along the Sabine Lake shoreline at Willow Bayou; a weir/plug at the opening at Starks South Canal Section 16 levee; and 232,000 linear feet of vegetated earthen terraces in the vicinity of Greens Lake.

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The project is located in the western portion of the Sabine National Wildlife Refuge from Pool 3 to the eastern shoreline of Sabine Lake in Cameron Parish, Louisiana.

Construction was completed in October 2010.

This project is on Priority Project List 10.

The Federal Sponsor is U.S. Fish and Wildlife Service

The Local Sponsor is CPRA