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| Innovative Techniques and Methods for Coastal Habitat Restoration |
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As the science of habitat restoration matures, coastal restoration
practitioners are developing new and innovative ways to increase the
efficiency and success of restoration efforts. Following are several
examples of recent or ongoing restoration projects that contribute to
our understanding of new practices for coastal habitat restoration.
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Salt Marsh Habitat
Salt marshes occur on all coasts of the United States around low-energy
areas such as estuaries, lagoons, bays and river mouths. They play
a vital role in the health of the coastal ecosystem. Salt marshes function
to help control floods, improve water quality, and contribute significantly
to coastal food webs. They provide valuable habitat for fish, birds,
and other wildlife. Over the past century, salt marshes have disappeared
at an alarming rate, primarily as a result of such activities as
dredging, filling, diking, and ditching. Natural salt marshes are a
function of their hydrology and must maintain a delicate balance between
salt water and fresh water.
Restore and Regulate Tidal Hydrology Projects
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| Figure 1. Removal of existing levee during the Deepwater Slough Restoration Project Courtesy: U.S. Army Corps of Engineers (USACE), Seattle District. |
The Deepwater Slough Restoration Project
South Fork of the Skagit River, Washington
The project seeks to restore the natural processes
and conditions of a 230-acre intertidal estuary that were disrupted
by diking, which eliminated the processes of river and tidal hydrology
and sediment supply.
Innovative component : The project removed 10,000 lineal
feet of existing levee — the first project in the Puget Sound region
to remove diking completely as compared to breaching (Figure
1). To date, this technique has been successful in restoring tidal hydrology
to the system.
Contact: Curtis_Tanner@fws.gov
Web link: http://www.new.usace.army.mil/publicmenu/DOCUMENTS/deepwater.pdf
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| Figure 2. Creation of a meandering tidal creek (bottom) with explosives
(top) for the Winchester Tidelands Restoration Project. Courtesy: South Slough National Estuarine Research Reserve. |
The Winchester Tidelands Restoration Project
South Slough National Estuarine Research Reserve,
Oregon
 Watch video...
This project has two primary goals: 1) to restore
full tidal hydrology to a series of diked and degraded estuarine wetlands;
and (2) experimental correction for marsh surface subsidence by creating
marsh mesocosms at different tidal elevations (see Restoration Research).
Innovative component: In a portion of the project area where
the marsh surface was too soft to accommodate dump trucks for removal
of excavated material, explosives were used carefully and effectively
to create a meandering tidal creek (Figure 2; video clip). In another
area, an innovative method for removing a large amount of dike in one
low tide window of opportunity was accomplished by digging vaults at
various locations behind the dike to be removed. Filling the vaults
with dike material as it was removed greatly speeded the time of dike
removal by eliminating the need to truck dike material offsite.
Contact: craig.cornu@dsl.state.or.us
Web link: http://www.southsloughestuary.org
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| Figure 3. Inspecting installation of sheet metal, which will house
the self-regulating tidegate. Courtesy: National Oceanic and Atmospheric
Administration Photo Library. |
Black Bayou Hydrologic Restoration Project
Over 25,000 acres of tidally-influenced intermediate
and brackish marshes in Cameron and Calcaieu Parishes, Louisiana
The purpose of the Black Bayou Hydrologic Restoration
Project project is to restore coastal marsh habitat and slow the conversion
of wetlands to shallow, open water.
Innovative component: A weir with a state-of-the-art, self-regulating
tidegate (SRT) was installed to regulate the amount of saltwater intrusion
into surrounding marsh habitat (Figure 3). In contrast to conventional
tide gates that close when the tide rises, the SRT can be adjusted to
allow tidal flow into the marsh behind it, closing only when a predetermined
high water level is reached. This restores tidal flushing of the marsh
while protecting upland property from flooding. Critical access for
fisheries is maintained through fish slots on either side of the SRT.
Contact: John.Foret@noaa.gov
Web link: http://www.lacoast.gov
SRT information available: http://www.watermanusa.com
> Return to top
Planting
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| Figure 4. High school students growing salt marsh plants for Tampa Bay Estuary restoration projects. Courtesy: Tampa BayWatch. |
High School Wetland Nursery Program (also known
as Bay Grasses in Classes)
Tampa Bay, Florida
Tampa BayWatch facilitates the construction
of salt marsh plant nurseries in the bay region's schools. With a 44 percent
loss of shoreline vegetation in Tampa Bay over the past 100 years, the
nurseries provide an inexpensive source of salt marsh plants for large-scale
restoration projects in the Tampa Bay Estuary. The nurseries are monitored
and maintained by students of all ages in coordination with school science
teachers and science and ecology clubs. Smooth cordgrass plugs are harvested
from a natural donor site and planted at the school nursery (Figure
4). After six to eights months of growth, the students transplant the
cordgrass at a restoration site.
Innovative component: It is estimated that the High School
Wetland Nursery Program saves public agencies approximately $69,000
per year in salt marsh plant purchase costs. This is the first program
to use school systems to develop a permanent source of plants. Similar
programs now exist in other areas such as Chesapeake Bay and Louisiana.
Contact: info@tampabaywatch (manual
and video available)
Web links: Tampa Bay, http://www.tampabaywatch.org
Chesapeake Bay "Bay Grasses in Classes", http://www.dnr.state.md.us/bay/sav/bgic/grass_class.html
Louisiana, http://lamer.lsu.edu/projects/coastalroots/index.htm
> Return to top
Shoreline Stabilization and Erosion Control
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| Figure 5. Aerial photo of constructed terraces in Little Vermilion Bay. Courtesy: U.S. Geological Survey (USGS). |
Little Vermilion Bay Sediment Trapping Project
Vermilion Parish, Louisiana
Coastal land in Louisiana continues to be lost
at staggering rate of 25 to 35 square miles per year. In the northwest
corner of Little Vermilion Bay, wind and wave energy increases shoreline
erosion and prevents Gulf Intracoastal Waterway sediments from settling
and forming the basis for vegetated marsh. In the Little Vermilion Bay
Sediment Trapping Project, a series of 100-ft wide by 6-ft deep channels
were dredged. The dredged sediments were then used to construct 23 earthen
terraces with a combined length of 23,300 feet (Figure 5). The bases
of the terraces were planted with 20,450 containers of smooth cordgrass.
Innovative component: Earthen terraces are used to diminish
waves such that sediment deposition will increase and erosion will decrease.
Preliminary monitoring has shown that the terraces are growing in width,
facilitating marsh growth.
Contact: John.Foret@noaa.gov
Web link: http://www.lacoast.gov
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| Figure 6. Polyester geotextile tube used for shoreline stabilization and marsh creation. Courtesy: NOAA Photo Library. |
The Barren Island Restoration Project
Chesapeake Bay, Maryland
Barren Island has been eroding dramatically,
threatening habitat loss and causing reduced protection for nearby seagrass
beds. The Barren Island Restoration Project used geotextile tubes filled
with sand dredged from the nearby ship channel to expand and stabilize
the island's shoreline. Tubes are constructed of high-strength polyester
or polypropylene fabric and filled hydraulically with dredge material
(Figure 6). Industry standards have recently been developed for geotextile
tube manufacturing and installation procedures. An 11-acre area behind
the tubes was filled with dredged material to restore intertidal elevations
and then planted with salt marsh vegetation. Volunteers hand-planted
the seedlings to restore the natural marsh community.
Innovative component: Use of geotextile tubes to control
erosion of marsh planted on dredge material behind geotextile tube.
Contact: rich.takacs@noaa.gov
Web link: http://www.ngs.noaa.gov/PROJECTS/Wetlands/Barren_Is/.
More information on geotextile tubes is available from the Geosynthetic
Research Institute Web page: http:// www.geosynthetic-institute.org,
link to GRI Specifications and Guides. See also article on Dredging
and Geotextile Tubes, available http://www.dredge.com/casestudies/tp_geot.htm.
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| Figure 7. Assenmbling Filtration Enhancement Devices (FEDS) (top) used to stabilize eroding salt marsh in New Hampshire (bottom). Courtesy: David Burdick, University of New Hampshire. |
Salt Marsh Restoration using FEDS
Portsmouth, New Hampshire
In New England, a combination of waves and ice
contribute to erosion of the lower edges of created and natural salt
marshes. At created marshes in Portsmouth, New Hampshire, Filtration
Enhancement Devices (FEDS) are used to stimulate marsh development.
FEDS are organic, biodegradable baffles designed to enhance filtration,
reduce resuspension of sediments, and intercept erosional sediments
in order to stabilize edges of eroding salt marsh in low wave-energy
environments. They also stimulate plant and animal colonization. FEDS
are constructed of two layers of erosion control fabric rolled tightly
around hay or wrack and can be assembled quickly by volunteers (Figure
7).
Innovative component: Use of Filtration Enhancement Devices
(FEDS) to stabilize edges of eroding salt marsh in low wave-energy environment.
Contact: dburdick@cisunix.unh.edu
Web link : http://ciceet.unh.edu/abstract.php?full_proj_id=17
> Return to top
Mangrove Habitat
Mangrove ecosystems represent a crucial link between land and sea
in tropical and subtropical regions. Mangroves and their associated
waters provide valuable habitat and food for a wide range of fish, birds,
mammals, reptiles, and amphibians. They also stabilize sediments and
protect coastal uplands from flooding. Loss of mangrove from coastal
Florida, Louisiana, and Texas can be attributed in large part to urban
and industrial development in the coastal zone.
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| Figure 8. Mangrove reestablishment at Cross Bayou, Florida. Courtesy: NOAA. |
Cross Bayou Mangrove Restoration
Pinellas County, Florida
The primary goal of the 11-acre project was
to establish a typical Tampa Bay mangrove forest. Rather than immediately
planting mangroves, as many mangrove restoration projects do, project
planners first determined if the site had normal tidal hydrology and
an available seed bank from adjacent mangrove stands. With these two
factors present, mangrove habitat can self-repair within 15 to 30 years.
At the Cross Bayou site, wetland elevation was restored and tidal creeks
were constructed to allow for tidal flushing. Because a source of seeds
was available from nearby stands, mangrove is recolonizing the site
through natural processes, eliminating the need to plant (Figure 8).
Two years of monitoring has shown that the success criterion for mangrove
cover (30 percent) has been significantly exceeded.
Innovative component: Working with natural recovery processes
to reestablish mangrove habitat.
Contact: Robin Lewis, lesrrl3@aol.com
Web link : not available
> Return to top
Seagrass Habitat
Seagrass beds are an integral part of the estuarine and nearshore
environments. They provide food for a variety of important species as
well as providing a platform for growth of an assortment of algae and
small animals, indirectly providing a food source for many other organisms.
In addition, seagrass beds provide refuge for a wide variety of nearshore
fish and invertebrate species. They also help stabilize sediments and
protect coastlines from erosion. Seagrasses are susceptible to activities
that reduce light, such as construction projects that increase suspension
of silt and sand or shading from docks and other overwater structures.
Excessive nutrient inputs from sewage discharge or agriculture can lead
to dense accumulations of macroalgae (seaweeds), which can smother seagrass.
Acitivities such as dredging and boating can impact seagrass by disturbing
the sediment in which it grows.
Stockpiling and Planting
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| Figure 9. Eelgrass plants growing in flowing seawater tank for later
transplant. Courtesy: Battelle Marine Sciences Laboratory. |
Clinton Ferry Terminal Eelgrass Transplant Project
Clinton, Washington
Eelgrass restoration was conducted as part of
the mitigation for terminal expansion in Clinton, Washington. Eelgrass
was salvaged from the area prior to construction. Planted in tanks (totaling
1560 ft 2 ) at a laboratory, the population increased fivefold (Figure
9), plants were then transplanted to areas near the site after construction
was complete. To date, over 19,000 ft 2 have been planted with cultivated
plants.
Innovative component: Salvaging the eelgrass from the site
enabled restoration to be conducted without impacting a healthy donor
bed.
Contact: amy.borde@pnl.gov
Web link: http://www.wsdot.wa.gov/ferries/your_wsf/
corporate_communications/clinton_enviro
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| Figure 10. Tying eelgrass shoots to TERFS frame prior to planting. Courtesy: Fred Short, University of New Hampshire. |
New Bedford Harbor Eelgrass Transplant Project
New Bedford Harbor, Massachusetts
"Transplanting Eelgrass Remotely with Frame
Systems" (TERFS) was perfected during a project to restore eelgrass
in New Bedford Harbor. Eelgrass shoots are tied to the bottom of a weighted
frame with biodegradable paper ties (Figure 10). The frame is lowered
onto the seafloor from a small boat and retrieved three to five weeks
later once the shoots have rooted and the paper ties have decomposed.
TERFS create 0.25 square meter patches at fairly high shoot densities
of 200 per square meter. The reusable frames allow for community involvement
in their deployment, and they protect against bioturbation.
Innovative component: Because the TERFS method does not require
SCUBA, it drastically reduces the cost of eelgrass restoration.
Contact: fred.short@unh.edu
Web links: http://shrimp.ccfhrb.noaa.gov/lab/fonseca/guide/chap3.pdf and http://savebay.org/bayissues/grass_transplant_1.htm
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| Figure 11. Eelgrass seeds harvested from the field in Naragansett
Bay. Courtesy: University of Rhode Island. |
Seed-based Eelgrass Restoration
Chesapeake Bay
For large-scale restoration projects, seed-based
eelgrass restoration is gaining more interest in some areas as a viable
alternative to transplanting. At multiple sites in Chesapeake Bay, recent
eelgrass restoration efforts have involved broadcasting seeds by hand
from a motorized boat. Seeds may be obtained by harvesting reproductive
shoots in the field in the spring or early summer. The shoots are held
in large tanks with flowing seawater at ambient temperature and salinity
until the seeds mature. The shoots are stirred daily in order to release
mature seeds. Within four to six weeks, the majority of seeds will have
been released (Figure 11). Seeds are then broadcast prior to the period
of germination.
Innovative component: Use of seeds for eelgrass restoration
provides an alternative to harvesting plants from donor beds for transplant,
a more labor intensive and expensive method.
Contact: jjorth@vims.edu.
More information on the collection and handling of seeds is available
in a publication by Granger and others, "A Practical Guide for the Use of Seeds in Eelgrass ( Zostera marina L.) Restoration", available
from the Rhode Island Sea Grant Communications Office, tel. (401) 874-6842.
Web link : http://www.vims.edu/bio/sav/restoration/
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| Figure 12. Mechanized underwater seed planter being used in Naragansett
Bay, Rhode Island for large-scale eelgrass restoration. Courtesy: Cooperative Institute for Coastal and Estuarine Technology. |
Mechanized Underwater Seed Planter
Naragansett Bay, Rhode Island
A mechanized underwater seed planter is being
developed to plant large areas with eelgrass seeds efficiently. The
planter is towed behind a boat and consists of a sled, which travels
over the sea bottom, and a pump that pushes seeds into the sediment
(Figure 12). The seeds are mixed in a gel before planting to help prevent
them from being displaced by waves, currents, or predators. Project researchers
plan to publish a pamphlet that will detail the design, construction
and deployment of the mechanical seed planter.
Innovative component: Use of a mechanized seed planter to
plant large areas with eelgrass seeds, providing an efficient and cost-saving
method for eelgrass restoration.
Contact: kale.matso@unh.edu; snixon@gso.uri.edu
Web link: http://ciceet.unh.edu/bulletins/nixon.html
Use of Seagrass Wrack for Restoration
Galveston Bay, Texas
Approximately 2200 acres of seagrass (consisting
primarily of shoalgrass) has been eliminated from West Bay in the Galveston
Bay System. To determine if seagrass wrack could be used to
restore seagrass beds successfully, seagrass wrack was collected from water intake
screens at the Central Power and Light Plant in Corpus Christi, Texas.
Large amounts of seagrass material collect on the screens and must be
raked off and trucked offsite to a landfill. Wrack was collected in
the late fall, when feeding ducks and larger waves produce a greater
volume of more viable seagrass material. The wrack was then experimentally
broadcast from a boat into two 60-meter diameter enclosures. Wooden
stakes were placed within the enclosures to catch drifting seagrass
material to facilitate the establishment of new plants. After four years
of the initial broadcasting, over 40 acres of clovergrass and shoalgrass
beds have recovered.
Innovative component: Recycling seagrass to restore seagrass
beds.
Contact: john_Huffman@fws.gov
Web link: http://www.tbeptech.org/SeagrassProceedgs/e-OtherCoastalAreas/145huffman.pdf
> Return to top
Fertilization and Protection
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| Figure 13. Sediment tube deployment into a propeller scar in the Florida
Keys. Courtesy: Kamille Hammerstrom, NOAA |
Use of Sediment Tubes to Repair Damaged Seagrass
Beds
Florida Keys National Marine Sanctuary
Sediment-filled tubes constructed of biodegradable
fabric are placed into propeller scars to enhance seagrass recovery
in shallow beds (Figure 13). Propeller scars are caused by motorboats
traveling in waters shallower than the draft of the vessel, and are
one of the fastest growing causes of habitat degradation in Florida.
Filling the scar with tubes brings the sediment to the surrounding level,
which enables seagrass to send out runners and heal over the tube. The
tubes disintegrate with time. To date, the sediment tubes appear to
be a successful method for deploying fine sediment, which would otherwise quickly
get eroded away.
Innovative component: Biodegradable sediment tubes placed
in propeller scars to speed recovery time of damaged seagrass beds.
Contact: Kamille.Hammerstrom@noaa.gov
Web link: http://www.seagrass.net/
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| Figure 14. Bird roosting stakes provide natural fertilization to enhance
seagrass recovery. Courtesy: Kevin Kirsch, NOAA. |
Use of Bird-Roosting Stakes to Enhance Recovery
of Seagrass Beds
South Florida
In South Florida, fast-growing seagrasses are
stimulated to grow in damaged seagrass beds by planting bundled bare
root shoalgrass plants among bird roosting stakes. The stakes are constructed
of 0.5-inch PVC poles fitted with a treated wood block on the top where
cormorants and terns can roost (Figure 14). While roosting, the birds
defecate into the water, providing a source of natural fertilization.
Once the damaged area has been stabilized by shoalgrass, the stakes
are removed to allow succession to turtlegrass, a slower growing climax
species. This is because shoal grass may out-compete turtlegrass
in a fertilized environment.
Innovative component: Bird roosting stakes provide a source
of natural fertilization to enhance recovery of damaged seagrass beds.
Contact: Jud.Kenworthy@noaa.gov
Web link: http://shrimp.ccfhrb.noaa.gov/~mfonseca/reports
> Return to top
Habitat Enhancement
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| Figure 15. Middle Harbor Habitat Enhancement Design. Courtesy: Port of Oakland. |
Middle Harbor Enhancement Program
Oakland, California
The Middle Harbor Enhancement Program will
use dredge material to restore a prior naval boat basin to shallow water
eelgrass habitat (Figure 15). The 190-acre Middle Harbor, dredged continuously
since the 1940s, is up to 40 feet deep at low tide, rendering it far
less productive than the well-lit shallows more typical of the bay. Hydrodynamic and bathymetric analyses
were used to determine areas with conditions most suitable for eelgrass
growth. These areas will be filled with clean, dredged sand to elevations
that allow sufficient light penetration for plant photosynthesis. Eelgrass
will be transplanted in separate planting plots to facilitate natural
seedling and vegetative expansion.
Innovative component: Use of dredge material to restore eelgrass
beds.
Contact: merkelinc@aol.com
Web link: http://www.portofoakland.com/environm/
> Return to top
Kelp Habitat
Kelp forests occur in cold, nutrient-rich waters and are among the
most biologically productive habitats in the marine environment. Giant
kelp and bull kelp are the key species in the kelp forests that stretch
from Alaska to California on the west coast. These "rainforests of the
sea" are critical to sustaining commercial and recreational fisheries.
An increase in sedimentation from urban runoff and toxins from sewage
discharge has degraded kelp habitat. Overfishing and hunting of many
of the natural predators of sea urchins has seemingly led to an increase
in many area sea urchin populations. Sea urchins are voracious consumers
of kelp.
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| Figure 16. Growing juvenile kelp (top) to restore coastal California
Giant kelp forests (bottom). Courtesy: California Coastkeepers. |
Southern California Regional Kelp Restoration Program
Southern California
Off the coast of Southern California, the kelp
forests have largely disappeared. This project uses an integrated approach
to restore subtidal kelp forests. Cultivated juvenile kelp, grown on
ceramic tiles in laboratory aquaria and in portable eco-Kart aquaria
placed in science classrooms, is outplanted when the kelp has reached
1 to 2 inches (Figure 16) (see Community Involvement article for more information on classroom program). Sporophyll bags
containing adult reproductive tissue are also used to help "reseed" barren
reefs, enabling young transplants to become established. Also, during
routine maintenance dives on the restoration plots, sea urchins may
be relocated to minimize damage from grazing and drift kelp may be opportunistically
transplanted on site.
Innovative component: Using several restoration methods in
an integrated approach to ensure success of kelp restoration.
Contact: kelplab@cacoastkeeper.org
Web link: http://www.cacoastkeeper.org
Use of Artificial Kelp Plants to Reduce Grazers
Southern California
A new tool was developed to protect giant kelp
transplanted in urchin-dominated areas. Artificial (plastic) kelp plants
sweep the substrate and create a whiplash effect, effectively "herding" the
sea urchins away from the transplant area
Innovative component: Use of artificial plants to protect
kelp transplants
Citation (no URL available): Vasquez, J.A., and R.H. McPeak.
1998. "A New Tool for Kelp Restoration." California Fish and Game. Volume 84, Number 4. Pages 149 to 158.
> Return to top
Reef Habitats
Oyster Reefs
Oyster reefs are typically found in estuaries, sounds, bays and tidal
creeks and provide important ecosystem services. Because oysters are filter
feeders, the reefs contribute greatly to water quality through
their enormous filtering capacity. They also provide valuable shelter
and habitat for many other estuarine organisms and serve as natural
breakwaters to reduce bank erosion. Once historically abundant throughout
U.S. coastal waters, oyster reefs have declined significantly due to
such causes as over harvest, water pollution, and destruction by shell
mining and fishing gear.
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| Figure 17. Newly placed oyster reef balls on the toe of a residential
seawall (left, Courtesy: Tampa BayWatch). An established oyster reef ball fully encased with oysters
(right, Courtesy: Reef Ball Development Group, Ltd.). |
Seawall Oyster Reef Program
Tampa Bay, Florida
Much of the natural shoreline in Tampa Bay has
been lost to the construction of seawalls. The loss of shoreline as
well as poor water quality has impacted the bay's scallop and oyster
fisheries. Through their seawall oyster reef program, Tampa BayWatch
is promoting the reestablishment of oyster reefs and other littoral
benthic communities by constructing seawall reef units along
residential and public waterfronts. Reef balls, constructed in two sizes
from nontoxic concrete mixture, are cured for about 1 week and then
placed in front of seawalls (Figure 17). The program uses volunteers
from youth groups, fishing organizations, homeowners associations, and
others to construct and install the reef balls. Once established, it
is anticipated that the oyster communities will improve water quality,
as mature oysters have the capacity to filter up to one liter of water
per hour. They are also expected to provide storm protection and habitat
for many species of shellfish, finfish, and other organisms.
Innovative component: Use of pre-cast concrete balls to restore
oyster reef habitat.
Contact: info@tampabaywatch.org
Web link: http://www.tampabaywatch.org/
> Return to top
Coral Reefs
Coral reefs are among the world's oldest living communities of plants
and animals and rival rainforests in species diversity. These habitats
are undergoing a pronounced decline from various human activities, such
as ship groundings, fishing practices, and general carelessness by boaters,
divers and snorkelers. Coral reefs can take decades or more to recover
under ideal conditions, and even longer in areas where stressors, both
man-induced and natural, are present.
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| Figure 18. Prefabricated reef modules (top) help to restore hard
bottom and coral reef habitat along the Florida coast (bottom). Courtesy: NOAA. |
Gulf Stream Pipeline Mitigation and M/V Wellwood
Restoration Projects
Florida coast
Along the Florida coast, the Gulf Stream Pipeline
mitigation project and other reef damage projects, such as the grounding
of the M/V Wellwood, seek to restore hard bottom and coral reefs by
deploying large limestone boulders (2.5 to 4.5 feet diameter) and prefabricated
reef modules (Figure 18). The modules consist of a hollow concrete and
limestone dome atop a reinforced concrete slab. Steps are taken to maximize
limestone exposure and minimize concrete exposure to mimic the natural
aesthetics and relief of the reef. Each module weighs approximately
3500 pounds. The domes are structured to provide habitat for a variety
of organisms and settlement areas for coral. The domes also contain
a center galley for fish refugia.
Innovative component: Use of prefabricated, limestone-covered
concrete modules to restore hardbottom and coral reefs.
Contact: wkjaap@worldnet.att.net, haroldhudson@noaa.gov
Web link: http://www.sanctuaries.nos.noaa.gov/special/wellwood/
> Return to top
Great Lakes Marsh Habitat
Coastal marshes of the Great Lakes are unique systems dominated by
large lake processes such as water level fluctuations, wave actions,
and wind tides. They store and cycle nutrients and
organic material into the aquatic food web and sustain a tremendous
number of diverse resident and migratory species. Pressures from shoreline
development have impacted the processes of sediment input and transport — processes
important to maintaining the bars and spits that shelter these highly-productive
marshes.
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| Figure 19. Restoration of Metzger Marsh on western Lake Erie, before and after. Courtesy: USGS. |
Metzger Marsh Restoration Project
Lake Erie, Ohio
Historical and geospatial data guided the restoration
of Metzger Marsh, a coastal wetland in western Lake Erie. The marsh,
a 300-hectare wetland in an embayment, once formed the mouth of a creek
that was channelized directly to the lake in the late 1800s. Also,
a barrier beach that protected the wetland from Lake Erie waves was
ultimately destroyed in 1973 by a combination of extremely high water
levels, storm events, and reduced sediment supply. This resulted in
a significant loss of wetland vegetation. Large-scale aerial photographs
were interpreted to delineate major vegetation types as well as the
historical boundaries of the barrier beach. A geographic information
system (GIS) was then used to digitize the data and calculate areas
of vegetation and barrier beach. Paleoecological studies were also employed
to identify historical vegetation species. Based on these studies, the
restoration program was designed to return the embayment to a fully
functional, vegetated coastal marsh with hydrologic connection to the
lake, similar to the original wetland (Figure 19). A dike was constructed
to mimic the functions of the barrier beach and included a water-control
structure to allow hydrologic connection to the lake. The water-control
structure contains five 2-m wide channels that can be manipulated individually.
It also contains an experimental fish-control system that restricts
passage of large carp while allowing other fish to pass through. Each
passageway contains fish baskets that can be lifted out to capture,
count, and measure fish.
Innovative component: Use of historical, geospatial, and
paleoecological data to guide marsh restoration in the Great Lakes.
Contact: Douglas_Wilcox@usgs.gov
Web link: http://www.glsc.usgs.gov/science/wetlands/Metzger.htm
> Return to top
Summary
The projects featured above are but a small selection of the many
new and innovative restoration activities occurring around the nation.
We are fortunate that a more recent trend to monitor and
manage adaptively our restoration efforts affords the opportunity for applied research — enhancing
our understanding and ability to effectively restore our coastal systems
(see also Innovative Research Article). The results of these projects will provide much-needed guidance for
restoration efforts of the future.
Additional information and citations are available in:
Borde, A.B., and others.
2003. National Review of Successful and Innovative Restoration Projects. Prepared
for NOAA Coastal Services Center, by Battelle Marine Sciences Laboratory.
Sequim, WA.
> Return to top
Glossary
bathymetric — pertaining to the measurement of ocean
or lake depth and the study of floor topograph.
benthic — pertaining to the sea bed, river bed or
lake floor.
bioturbation — the mixing of a sediment by the burrowing,
feeding, or other activity by living organisms.
breaching — the practice of creating a gap (e.g.
culvert) in a dike or levee to restore tidal flow.
climax species — a species that is characteristic
of a more or less stable biotic community which is in equilibrium with
existing environmental conditions and which represents the terminal
stage of an ecological succession.
filter feeders — organisms that feed by straining
particles from the water column.
hydrodynamic — pertaining to the
action of water, waves, or tides.
mesocosm — an intermediate sized-community that
is taken as representative of a much larger ecological system.
littoral — pertaining to the intertidal zone of
the seashore.
refugia — areas in which prey may escape from or
avoid a predator.
wind tides — or seiches, are lakewide, short-term
displacements of water that are wind-induced. Water depth can increase
along a shoreline when water is pushed up by winds. Once the wind is
reduced, the water mass continues to oscillate, much like the water
in a bathtub that sloshes back and forth.
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