|
|
(restricted) |
|
|
|
|
|
|
|
Barrier
Shoreline Restoration |
|
The Barrier Shoreline Restoration
aspect of the Louisiana Coastal Area, Louisiana – Ecosystem Restoration:
Barrier Island Restoration, Marsh Creation, and River Diversion, Barataria
Basin Feasibility Study, is investigating the restoration of the barrier
islands and barrier shorelines in the Barataria Basin in Louisiana.
Purpose:
The overarching goal of the Coast 2050 Plan is to sustain a coastal ecosystem
that supports and protects the environment, economy, and culture of southern
Louisiana, and contributes greatly to the economy and well being of the
nation. The purpose of the Coast 2050 strategies for the Barataria Basin
is to restore and/or protect the natural and human environment to create
a sustainable ecosystem in the Barataria Basin within the context of the
Gulf of Mexico ecosystem, including coastal Louisiana. This aspect of
the study investigates barrier shoreline strategy R2-22 of the Coast 2050
Plan for the Barataria Basin. The purpose of this investigation is to
develop projects to provide and sustain the typical ecological attributes
(unique arrangement of habitats including shallow intertidal zone, beach,
dunes, back marsh, bays, and passes) of the barrier islands, headlands,
and shoreline in the Barataria Basin.
Action Area:
The barrier shoreline system in Barataria Basin begins about 72 km (45
miles) northwest of the mouth of the Mississippi River (Southwest Pass)
and forms a concave arch with respect to the Gulf of Mexico at the southern
end of the Barataria Basin. Barrier islands, headlands, and shoreline
offer unique ecological characteristics with an array of intertidal bottoms,
beaches, dunes, shrub thickets, maritime forests, and salt marshes not
present in interior wetlands. The assemblage of plants and animals is
different than can be found in any other area of the basin or in Louisiana.
Some of the species are endemic to barrier areas. A variety of seabirds,
wading birds, and shore birds such as black skimmer, reddish egret, piping
plover, and least tern utilize barrier islands. The islands serve as resting
areas for migrating birds, nesting locations for birds such as brown pelican,
and possible nesting beaches for sea turtles, as well as providing unique
habitats for many fish species.
The barrier shoreline in Barataria Basin from Bayou Lafourche to Sandy
Point has undergone significant movement and reduction in size during
the past 100 years. While some lateral movement of the shoreline is expected
as sand is reworked in the nearshore environment, the shoreline has retreated
rapidly. Tidal passes that have opened in the islands during the passage
of storms have not resealed in fair weather. Increase of the tidal prism
of Barataria Bay, which has occurred as a result of wetland losses in
the Barataria Basin, has amplified the barrier shoreline loss rate. Islands
have diminished in size (narrowed) to the point that they are likely to
vanish in the near future. For example, it is predicted that Grand Terre
Island may be gone by 2008 (Reed et al. 1995). Overall, the Barataria
barrier islands decreased in area by 47 percent from the 1890s to 1988.
The Caminada-Moreau Headland, forming the western portion of the Barataria
barrier system, has experienced some of the highest rates of shoreline
movement on the Louisiana or Gulf coast. Between 1978 and 1988, the coast
retreated at a rate of 13.6 meters/year (45 ft/yr). The shoreline has
retreated over 1.6 km (1 mile) in some locations from 1887-1988 (Williams
et al. 1992). The Plaquemines Barrier System in the eastern portion of
the system retreated at an average rate of 5.5 meters/year (18 ft/yr)
from 1884-1988. In 1884, Grand Terre Island was 1,699 hectares (4,193
acres) with an average width of 909 meters (2,982 ft), but by 1988, it
was only 513 hectares (1,266 acres) with an average width of 530 meters
(1,739 ft). In 1884, Shell Island was 127 hectares (313 acres) with a
width of 136 meters (446 ft). In 1988, it was 69 hectares (170 acres)
and 105 meters (345 ft) in width (Williams et al. 1992). The shoreline
has retreated 0.8 to 1.2 km (0.5-0.75 miles) over a large part of the
Plaquemines Barrier System.
Many of the barrier shoreline areas in Barataria Basin have become nothing
more than fragmented, low mounds of sand, easily washed over by minor
storm events, and provide poorer habitat than fully developed barrier
islands. As the barrier shorelines become narrower and disintegrate, bays
and wetlands behind them become more directly connected with the Gulf
of Mexico. This exposes the more fragile landscape features to higher
wave action and higher salinity water.
The
study area is located in Lafourche, Jefferson, and Plaquemines parishes,
and includes the barrier shorelines, barrier islands, passes, and back
marshes from Belle Pass on the west to Sandy Point on the east. In addition
to creating valuable habitat for wading birds, waterfowl, fishes, migratory
neotropical songbirds, shrimp, crabs, and other organisms, the proposed
action provides other advantages:
1. The
proposed alternatives potentially provide a low risk and quickly implementable
plan to address coastal land loss in the Barataria Basin;
2. The
proposed alternatives are strategically placed in the study area and could
potentially yield benefits to other coastal resources within the unique
Barataria Basin ecosystem, and the human infrastructure associated with
transportation, oil and gas extraction, utilities, etc.;
3. The
proposed alternatives could be implemented independently of the remaining
Coast 2050 Plan strategies for the Barataria Basin.
During the Coast 2050
public meetings conducted in 1998, Strategy R2-22 – Restore/Maintain Barrier
Headlands, Islands, and Shorelines, was considered a viable ecosystem
restoration strategy. Hence, this strategy will be developed into alternatives
for the potential action. Other alternatives that will be considered include
the No Action Alternative, alternatives presented in the
Barrier Shoreline Feasibility Study, and alternatives developed during
the scoping process. Alternative plans developed will investigate sand
nourishment, dune restoration, beach restoration, back marsh restoration,
shoreline stabilization, vegetative planting, or combinations thereof.
Barrier shoreline restoration design features will be evaluated to ensure
compliance with current Federal and State laws and regulations. Any adverse
effects of the alternative plans will be identified and appropriate mitigation
measures will be included in the plans. However, because the proposed
action is ecosystem restoration, it is not the intent to generate alternative
plans that would require mitigation. An
Environmental Impact Statement (EIS) will be prepared during the feasibility
phase because of the potential for significant direct and indirect, secondary,
and cumulative impacts on the human and natural environment.
References:
Reed, D.J., E.M. Swenson, and J.G. Gosselink. 1995. Physical Setting.
D.J. Reed (ed.) pp. 9-23. In: Status and Trends of Hydrological Modification,
Reduction in Sediment Availability, and Habitat Loss/Modification in the
Barataria-Terrebonne Estuarine System.
BTNEP No. 20. Barataria Terrebonne National Estuary Program, Thibodaux,
LA.
Williams, S.J., S. Penland, A.H. Sallenger, Jr. (eds.) 1992. Atlas of
shoreline changes in Louisiana from 1853-1989. U.S. Geological Survey,
Reston, VA.
Barrier
Shoreline Restoration Notice of Intent - Federal Register: April 28, 2000
(text)
Barrier
Shoreline Restoration Notice of Intent - Federal Register: April 28, 2000
(PDF 138 KB)
Barrier
Shoreline Scoping Report (PDF
1.31 MB)
|