Reclamation and Restoration Professional Practice Network
Ecological Restoration of the Louisiana Coastal Marsh
by Kenneth Bahlinger and Lee R. Skabelund
Importance of Louisiana’s Coastal Ecosystems

Louisiana contains approximately 40% of the coastal marsh area in the contiguous United States. However, since the early 1900s, the general trend of land building in the Louisiana coastal marsh (also known as the expansion of wetland habitat) has been reversed. Much of the loss of coastal marsh is attributed to a decrease of sediment delivery resulting from navigation and flood controls on the Mississippi River, saltwater intrusion into previously fresh and brackish coastal marshes, dredge and fill activities associated with the exploitation of the area’s mineral resources, and natural geological subsidence of Holocene Mississippi River Delta plain sediment. Estimated losses of coastal marsh for Louisiana’s entire coastal zone are approximately 25 square miles per year.

Louisiana’s coastal marsh is a major source of resources for the U.S., providing approximately 26% of our commercial seafood and 33% of the oil and gas we use, offering habitat for an estimated five million migratory waterfowl, and benefiting 19% of the nation’s waterborne commerce. Louisiana’s barrier islands and coastal marsh are also important in reducing storm surges and protecting local communities and inland freshwater habitats.

State and Federal Restoration Efforts 

In 1989, the Louisiana Department of Natural Resources/ Coastal Restoration Division (LDNR) was mandated by R.S. 49:213 of the Second Extraordinary Session of the Louisiana Legislature to conserve, restore, create, and enhance the coastal marsh of Louisiana. Most early coastal restoration projects were small in scale (10 to 50 acres) and focused on local coastal ecosystem restoration. Through the years, coastal planners, academics, engineers, and biologists have come to better understand the complexity of the coastal ecosystem and the need for large-scale coastal restoration projects (100 to 10,000 acres) that impact, create, and nourish more extensive areas of wetland habitat.

In 1990, passage of the Coastal Wetlands Planning, Protection and Restoration Act (CWPPRA; PL-101-646, Title 111), locally referred to as the Breaux Act, provided authorization and funding for a multi-agency task force (five federal agencies and the state of Louisiana) to begin actions to curtail wetland losses. The process that CWPPRA coastal restoration projects go through during project development, planning, implementation, and monitoring is very similar to the guidelines for ecological restoration developed by the Society for Ecological Restoration International (SERI 2005). Following this process is crucial for proper development of a project; however, it increases the time to implement projects.

In 1998, after extensive studies and construction of a number of coastal restoration projects accomplished under CWPPRA, the State of Louisiana and the federal agencies adopted a new coastal restoration plan, “Coast 2050: Toward a Sustainable Coastal Louisiana.” The plan called for the use of larger-scale wetland restoration efforts and focused on restoring more natural hydrology and reintroducing sediments into degraded coastal marsh ecosystems. Timing is critical in the construction of large-scale coastal restoration projects so that they can promptly function and begin reaching their marsh habitat restoration goals. However, building larger projects increases project costs, impacts to landowners, time for the permitting process, and ultimately time for project implementation.

Early in fiscal year 2002, it was recognized that a more in-depth, comprehensive study was needed. To fulfill this need, the Louisiana Coastal Area Louisiana Ecosystem Restoration Study was initiated for preparing plans and specifications to implement proposed projects.

Impacts Associated with Hurricanes Katrina and Rita 

In 2005, many of Louisiana’s coastal marsh habitats were severely impacted by hurricanes Katrina and Rita. The resulting devastation (especially acute for barrier islands) showed the increasing vulnerability of the health, safety, and welfare of coastal communities and cities and has opened the eyes of the nation and federal government to the extent of Louisiana’s coastal marsh loss and the critical need to restore it.

The following images provide a glimpse at some of the changes brought by these two hurricanes, and highlight the fact that these two storms both benefited and challenged coastal ecosystems.
Chandeleur Island

Chandeleur Island, Breton National Wildlife Refuge lies east of the
Mississippi River Delta, the crescent-shaped barrier island seen
at the far right of the LDNR image above.

(Source: http://sonris-www.dnr.state.la.us/www_root/sonris_portal_1.htm)
 

Well east of New Orleans

Well east of New Orleans (Chandeleur Island, Breton National
Wildlife Refuge) the impact of Hurricane Katrina on these arcshaped
barrier islands was quite severe. (Source: USGS National
Wetlands Research Center, Lafayette LA.) 

Photo of coastal marsh

Photo of coastal marsh shortly
after Hurricane Katrina.
(Source: Louisiana Department
of Natural Resources.) 

One year later

One year later many of these
wetlands are flourishing.
(Source: Louisiana Department
of Natural Resources.) 

In 1991, the Caernarvon Freshwater Diversion was the first large scale project constructed that utilized sediments and freshwater from the Mississippi River to replicate the annual flooding and sediment deposition before man built levees. This successful project was in the direct path of Hurricane Katrina (see USGS images below) and its project area was severely impacted. As soon

Before and after hurricanes Katrina 

Before and after hurricanes Katrina and Rita. (Source: USGS
National Wetlands Research Center, Lafayette LA.)

as possible after the storm, the project was operating at high capacity to flush out the salt water and re-nourish the project area.

Coastal Restoration Programs and Project Examples 

One state-funded program is the LDNR Vegetative Planting Program. This multi-agency marsh vegetation planting program is implemented through the local coastal Soil and Water Conservation Districts (SWCD). The LDNR Vegetation Planting Program involves teamwork by state, federal, and local agencies to reestablish native marsh coastal vegetation. Agencies include the LDNR and Louisiana Department of Agriculture and Forestry, the Natural Resources Conservation Service, and the SWCD.

In an attempt to combat coastal marsh loss, many other types of projects have been planned and implemented through LDNR, including freshwater diversions, sediment diversions, beneficial use of dredged material, marsh management, shoreline protection, terracing, and vegetation plantings.

Although there is an immediate need for freshwater diversions to be built in order to help restore marsh habitats, as outlined in the SERI Guidelines for Ecological Restoration (SERI 2005), the proper protocol in the planning and implementation of such projects requires sufficient time to thoroughly and reflectively move through the planning, design, and construction process.

Barrier islands are the first lines of defense against storm surge and large waves. They are periodically nourished with dredged sand; sand fencing to conserve dry, blowing sand; and vegetation installed to conserve the sand and extend the lifetime of the barrier island. Over time, the island’s flora progresses through succession and becomes reinhabited by plants and animals.

Sand fencing 

Sand fencing on Trinity Isles,
Dernieres in 1999. (Source:
Louisiana Department of Natural
Resources.) 

Sand fencing-2

Sand fencing on Trinity Isles,
Dernieres in 2004.
(Source: Louisiana Department
of Natural Resources.) 


The re-establishment of native marsh vegetation in coastal restoration projects is an important and efficient component for making a coastal restoration project successful. Many of these projects involve structures, dredge disposal deposits, levees, freshwater diversions, or a combination of these, incorporating the planting of native marsh vegetation. Since 1990, the LDNR has been involved with the planting of over 270 coastal sites. The planting of native marsh vegetation is one of the most cost efficient types of coastal restoration projects. The costs of marsh vegetation plantings average five dollars per foot compared to hundreds of dollars per foot for hardscape shore protection projects such as rock, groins, weirs, etc.

Terracing is a more recent type of coastal restoration project where small earthen dikes are built across areas of open water. Terraces reduce fetch (the distance across open water) and subsequent wave erosion and also increase fisheries habitat. The initial projects have fared well and terracing has become a popular coastal restoration technique. CWPPRA projects, agencies, and private landowners frequently construct this simple,

Terracing in Nov 
Terracing in Nov. 1990, 3
months after construction.
(Source: Louisiana Department
of Natural Resources.) 

Terracing in Jan 
Terracing in Jan. 2003, 13
years post-construction.
(Source: Louisiana Department
of Natural Resources.)


low cost innovation for mitigation efforts and habitat restoration in interior marshes. Most terraces felt the brunt of the hurricanes, but fared well.

Role of Landscape Architects in Coastal Restoration 

Typically, those trained as landscape architects are well suited for coastal restoration project work. However, the idea is relatively new, especially to human resource departments. For example, the job description for Landscape Architects at LDNR has only recently been changed from a “traditional landscape architect” who designs public spaces such as scenic highways, parks, and rest areas, to one that better represents the duties of one who works with wetland ecosystems. Landscape architects working at LDNR are currently employed as “wetland restoration specialists” rather than simply serving as “experts in planting design, layout, and installation.”

The field of landscape architecture, which typically includes large-scale ecosystem planning and design, communication skills, and professional practice, provides many of the qualifications needed for ecosystem restoration today. The landscape architect as specialist in ecological land planning and ecosystem restoration is becoming more common as engineering and environmental firms realize the ability of LA’s to understand environmental matters on a larger scale while also functioning as project managers and detailed designers. Landscape architects who understand how to strike a balance between the concerns of both engineers and biologists/ecologists are well positioned to play an active role in large-scale landscape planning/design/development and ecosystem reclamation and restoration.

At the LDNR, duties of practicing Landscape Architects include “Coastal Restoration Project and Program Manager” of various large coastal restoration projects and programs as well as coordination of the bidding and planting of coastal restoration vegetative planting projects.

Concluding Thoughts 

The prospect of the LDNR coastal restoration program is for larger scale construction projects, continued adaptive management of marsh restoration programs, and increased funding to implement many types of coastal restoration programs and projects.

Through the years, it has become apparent that it is easier to work with and use existing natural processes to restore coastal ecosystems—typically called “process- based restoration.” Working with nature by helping to create coastal marsh ecosystems, rather than working against nature by seeking to simply protect dynamic coastal ecosystems, generally costs less and is more productive in promoting the long-term conservation of coastal marshes. Time, money, teamwork, and place-based knowledge are required if we really want to restore Louisiana’s coastal wetlands.

For additional information on Louisiana’s coastal restoration program and hurricanes Katrina and Rita, please visit http://www.lacoast.gov.

References:

Dunbar, J. B., L. D. Britsch, and E. B. Kemp. 1990. Land Loss Rates Report 2, Louisiana Chenier Plain. Tech. Rpt. GL–90–20. Department of the Army, Waterways Experiment Station.

Boesch, D. F., ed. 1982. Subsidence in Coastal Louisiana: Rates and Effects on Wetlands. Proceedings of the Conference on Coastal Erosion and Wetland Modification in Louisiana: Causes, Consequences, and Options. U.S. Fish and Wildlife Service, Biological Program, FWS/OBS-82/59.

Coastal Protection and Restoration Authority of Louisiana. 2006. Comprehensive Coastal Protection Marsh Plan for Louisiana.

Dunbar, J. B., L. D. Britsch, and E. B. Kemp. 1992. Land Loss Rates Report 3, Louisiana Coastal Plain. New Orleans: U.S. Army Corps of Engineers. 28 pp.

Louisiana Coastal Area, Louisiana Ecosystem Restoration. http://www.lca.gov/learn.aspx

Louisiana Department of Natural Resources. 1998. Coast 2050: Toward a Sustainable Coastal Louisiana. December 1998.

Louisiana Department of Natural Resources/Office of Coastal Restoration and Management 2000. Working to Save our Coastal Wetlands.

Society for Ecological Restoration International (SERI). 2005. A Society for Ecological Restoration Publication: Guidelines for Developing and Managing Ecological Restoration Projects. Co-authored by: Clewell, A., Rieger, J. and J. Munro. December 2005. Available online at: http://www.ser.org/content/guidelines_ ecological_restoration.asp (accessed 12/11/06).

USDA/NRCS Plants Materials Center. http://plant-materials.nrcs.usda.gov/ 

Kenneth Bahlinger is a Project Manager and Coastal Restoration Scientist with the Louisiana Department of Natural Resources. He can be reached at kennethb@ dnr.state.la.us. Lee R. Skabelund, ASLA, of Kansas State University, can be reached at lskab@ksu.edu.
 
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Lee Skabelund, ASLA, Chair
(785) 532-2431  
lskab@k-state.edu