ASLA 2003, Gulf Coast Restoration Tour - led by K. Bahlinger & G. Grandy, Louisiana Department of Natural Resources, Coastal Restoration Division
On October 30, 2006 a small group of ASLA members boarded a bus and headed out to see a number of coastal marsh restoration sites south and west of New Orleans.
Stops included the USDA-NRCS Plant Materials Center; Port Fourchon Beach and Black Mangroves; Grand Isle (with visits to the beach and at The Nature Conservancy boardwalk); and Grand Isle State Park (where we capped the day with a mouth-waterin' Shrimp Boil Dinner – graciously hosted by local residents on Grand Isle).
Thanks to superb work by Greg Grandy and Kenneth Bahlinger, it was an enjoyable and very informative day. The field trip foreshadowed important ideas gleaned at the educational session which followed on November 1, 2003.
As briefly described in the detailed abstract for the 2003 ASLA Meeting in New Orleans, the importance of Louisiana’s coastal ecosystems to the U.S. is profound (refer to ASLA Session ID#: D4 11/01/3:30pm-4:15pm). Excerpts from the session abstract discuss primary ecological concerns and note the hope associated with restoration activities: From an ecological vantage-point, the Mississippi River Delta contains the greatest natural mosaic of bottomland forests, swamps, marshes, and barrier islands in the United States. However, since 1930, the Mississippi River delta plain has seen hundreds of thousands of acres of valuable habitat converted to open water due to both anthropogenic and natural processes. Flood- and diversion-control projects altered natural patterns of water and sediment delivery and led to the de-stabilization of wetland surfaces and regional subsidence. Localized or acute wetland loss since the 1930’s are related to the footprint of cities, towns, agriculture and human infrastructure on this deltaic landscape, combined with ongoing natural processes. With authorization of the “Coastal Wetland Planning, Protection, and Restoration Act” and freshwater-diversion projects in the 1990’s, Louisiana began an era of coastal restoration science, and is now re-engineering the Mississippi River delta and plains. It is possible that the new strategies and methodologies being developed in Louisiana will help scientists, designers, engineers and managers rescue the world’s river deltas. Nevertheless, the ongoing challenge will be to create sustainable approaches to using and replenishing our coastal landscapes over the decades to come.
Here is what we saw and discussed during the field trip – with a notes by Kenneth Bahlinger about how each of these places fared during hurricanes Katrina and Rita: NRCS Plants Materials Center (PMC), Golden Meadow -
The PMC is a federal plant research facility with an emphasis on coastal plants. We received an excellent overview of plants being grown for various kinds of restoration projects. We also said hello (at a safe distance) to several albino alligators.
Golden Meadow PMC (lrs)Port Fourchon Dredge Disposal Site & Black Mangroves
- As one of the largest commercial ports in the U.S., this port is the hub for several large oil companies. Projects have been constructed to protect the beach and marsh. By boat, we shuttled out to an area where sediments and soil had been placed in an area formerly dominated by deep, open water. Establishment of the marsh was vigorous in most areas (except where lack of organic material inhibited vegetative growth), and these restored marshes were serving as important resources for fish, wildlife, and the protection of pipelines, roadways, and other human infrastructure.
Open Water near Port Fourchon (lrs)
Port Fourchon Marsh Restoration (lrs)
Grand Isle Break Waters/Groins/ Beach Plantings & The Nature Conservancy Boardwalk
- Here we witnessed the effects of Tropical Storm Isidore and Hurricane Lili, observed U.S. Army Corps of Engineers activities (including the use of large, cement-filled geotextile tubes, and groins [rock piles placed perpendicular to the shoreline which tend to starve the down-current sides of the shoreline]), visited several different LDNR dune plantings (simple but effective sand-fencing and planting strategies), and spent time assessing The Nature Conservancy’s hardwood restoration efforts. Grand Isle State Park
- Before our shrimp boil on the Grand Isle Fishing Pier we visited Grand Isle State Park and reviewed the dynamics of this ever-changing coastal landscape, discussing lessons learned from ongoing coastal restoration activities.
Geotextile tubes along the Gulf Coast (lb)
(these concrete filled tubes were lifted and
moved during the 2005 hurricane season)
LADNR dune plantings near Grand Isle (lrs)
Grand Isle State Park (lrs)
Evening Shrimp Boil in Grand Isle (lrs)
The effect of the two powerful hurricanes in 2005 wrought significant changes to Grand Isle and the other sites we visited on October 30, 2003. On the following pages some of the changes brought by hurricanes Katrina and Rita are briefly summarized.
These reflections provide are useful as local residents, politicians, planners, designers, ecologists, and other scientists consider future reclamation, restoration, and re-building efforts along the Gulf Coast of Louisiana as well as other storm-prone landscapes. Post-Hurricane Updates by Kenneth Bahlinger, Louisiana DNR
NRCS Plants Materials Center (PMC), Golden Meadow The PMC incurred some damage from Hurricane Katrina. Most of the structural damage was from wind. The site was inundated with water. However, the water was not an extreme storm surge such as occurred at Grand Isle and on the Mississippi Gulf Coast. The PMC did not receive much damage from Hurricane Rita probably because of the damage already caused by Hurricane Katrina. The PMC was more affected by the high water and lack of electricity. With the high water, access was limited to boats for a day or two. The lack of electricity shut down the greenhouses so the cooling and irrigation systems were in operative for a while, resulting in some plant mortality.
The PMC spent several months getting their plant stock and greenhouses back to full capacity. Today the PMC is back to near normal. Port Fourchon The dredged disposal site we visited fared well. In previous discussions with the PMC, they indicated most of their trees were burned by the surge and salt, but appeared to be recovering. The marsh grasses were generally unaffected. The dredged disposal area overall did quite well. While I cannot document this, I would expect that the storm surge redistributed some of the dredged sediments and shaped the site by evening out some of the low and high spots. Too, the hurricanes probably introduced additional sediments and nutrients, which should benefit the site.
The concrete geotextile tubes that we observed lining the Gulf of Mexico shoreline at the end of the road were uplifted and moved. The barge breakwaters with rock remain in place. Otherwise the shore here was not damaged much.
Something to note is that along the shoreline for several miles to the east of the geotextile tubes and barge breakwaters, several large cuts in appeared as a result of the hurricanes. During a fishing trip to the area in the summer of 2006, the cuts did not seem as wide as they had been described to me. From my observation they had filled in quite a bit. This is typical of the fact that it takes a year or so for displaced sand to reappear. Regardless, the shoreline here and elsewhere did roll back about a hundred feet or so, which is typical for such a storm event. Grand Isle The town and island of Grand Isle suffered quite a blow, though it could have been much worse had Hurricane Katrina come ashore just a few more miles to the west. Although almost every structure on Grand Isle had some degree of wind damage, most of the major damage on Grand Isle occurred on the north side and western end of the island by the storm surge from the northeast winds that pushed the bay water over the island. The middle and southern side of the island, the most elevated parts, had water, but were generally protected from the storm surge effects. Many camps, homes, and commercial buildings on the north facing side of Grand Isle were completely wiped away, leaving slabs and pilings. One could see how the quality of construction made a difference. I observed as an example one structure gone, while one adjacent with minor damage.
Some long term effects from the hurricanes are that the west and the north side of the island are still mostly void of camps and houses. This is likely because of new building codes that now require any new houses, camps and permanent trailers be built at least 12 feet off the ground. Construction codes are also being upgraded. The cost to do this is high. Many of the camp and homeowners did not have adequate insurance prior to the hurricanes. Insurance on a barrier island vulnerable to hurricanes was very high even before the hurricanes and is now unavailable or substantially more expensive.
Beach Plantings - The beach plantings of bitter panicum that we observed survived both of the 2005 hurricanes and actually benefited from them. Bitter panicum thrives best when sand is transient. When planted on open sand it grows and spreads very quickly and traps sand. Over time the trapped sand stops moving as the vegetation grows thicker. I had observed over the years that the bitter panicum we had planted had become less vigorous due to the fact that the sand had stabilized. During the hurricanes there was no deposition of sand on the bitter panicum. During a visit in July 2006 the plants looked more vigorous and vibrant. This was probably the result of the wind, rain, and water moving the sand. Groins - The groins we observed were unaffected by the hurricanes.
Break Waters - The breakwaters on the north side of the island and the ones on the front of the island near the Grand Isle State Park were unaffected. The breakwaters are not designed to stop storm surge.
The Nature Conservancy Boardwalk - The Nature Conservancy Boardwalk was located on the north side of Grand Isle and was severely damaged. According to personnel at The Nature Conservancy the boardwalk has been repaired. Grand Isle State Park - I visited the Grand Isle State Park in June 2006. The upland vegetation was damaged from wind and salt water. The density of vegetation is not quite as thick, though it is recovering. The boardwalk, tower, and visitor’s center had minor damage. The beach is still there, though there was some shifting of sand. The pier out onto the Gulf of Mexico was destroyed and is currently being rebuilt.
For more information regarding the plans and initiatives being undertaken in Louisiana, please refer to the following Internet websites: http://www.lacoast.gov/cwppra/reports/saving_coastal_louisiana.pdf
SAVING COASTAL LOUISIANA: A National Treasure. Recommendations for Implementing an Expanded Coastal Restoration Program from the Committee on the Future of Coastal Louisiana, February 2002. http://www.lacoast.gov/cwppra/reports/RestorationPlan/index.htm
Louisiana Coastal Wetlands Restoration Plan. http://www.lacoast.gov/programs/2050/MainReport/report1.pdf
Coast 2050: Toward a Sustainable Coastal Louisiana. Louisiana Coastal Wetlands Conservation and Restoration Task Force and the Wetlands Conservation and Restoration Authority. Louisiana Department of Natural Resources. 1998. http://www.lacoast.gov/programs/DavisPond/index.htm
Davis Pond & Caernarvon Freshwater Diversion Projects.
Additional references include:
Bahlinger, K. 2003. “Marsh Vegetation Plantings on Louisiana Coastal Restoration Projects” in ASLA 2003 Annual Meeting Abstract Book
. American Society of Landscape Architects. Washington, D.C.
Cairns, J. Jr. 1999. “Ecological Restoration: A Major Component of Sustainable Use of the Planet” in Renewable Resources Journal
, Vol. 17, No. 1. Bethesda, Maryland.
Egan, D. & E.A. Howell. 2001. Historical Ecological Restoration Handbook: A Restorationist’s Guide to Reference Ecosystems
. Washington D.C.: Island Press.
Ehrenfield, J.G. 2000. “Defining the Limits of Restoration: The Need for Realistic Goals” in Restoration Ecology: The Journal of the Society for Ecological Restoration
, Vol. 8, No. 1. Blackwell Science, Inc.
Middleton, B. 1998. Wetland Restoration, Flood Pulsing and Disturbance Dynamics
. Wiley & Sons. New York.
Mitsch, W.J. & J.G. Gosselink. 2000. Wetlands, 3rd Edition
. Wiley & Sons. New York.
National Research Council.1992. Restoration of Aquatic Ecosystems
. Washington D.C.: National Academy Press.
Skabelund, L.R., Davis, D.W., Penland, S. & D. Reed. “Gulf Coast Conservation and Restoration” in ASLA 2003 Annual Meeting Abstract Book
. ASLA. Washington, D.C.
Vairin, B. 2000. Coastal Louisiana’s Future Jeopardized by Continued Land Loss: Watermarks, Winter 2000 Special Edition
. U.S. Geological Survey, National Wetlands Research Center. Lafayette, Louisiana.