United states department of interior bureau of ocean energy management

1.7General Construction Methods

The proposed construction method to construct the marsh platforms on East Timbalier and the West Belle Headland would require construction of containment dikes to help retain hydraulically dredged sediment within the footprint of the marsh platform.

On East Timbalier Island, the marsh containment dike will be constructed from sand excavated from the Ship Shoal or South Pelto Borrow Areas, transported to the pump-out area, offloaded via the sediment pipeline, and deposited to create the dike. The sediment would be mechanically shaped.

The marsh containment dike for the West Belle Headland Restoration Area will be constructed with in-situ sediments excavated and placed by a barge mounted bucket excavator or track mounted articulated arm bucket excavators (marsh buggies). Sediment to create the marsh platform would be transported via pipeline and positioned within the marsh fill area with a marsh buggy. The containment dikes help retain hydraulically dredged sediment while the marsh platform undergoes compaction and dewatering and are expected to degrade naturally over time. If necessary, dikes would be gapped within the first three years to allow for tidal exchange with the created marsh and to prevent ponding of water within the containment area. Considerations regarding if and when mechanical gapping will be conducted will be based on site inspections and determinations will be made in cooperation with natural resource agencies.

Equipment would be transported to the construction site via barges, tugboats, and crew boats. In addition, there may be a quarter’s barge on site for housing the crew. Construction access to East Timbalier Island and the West Belle Headland will be limited to the permitted construction access corridors. Personnel transport would be facilitated by use of boats and/or small all-terrain vehicles.

Sand Fencing

The dune platform of all of the Project features will have sand fencing installed along the centerline. The single row of sand fence will promote deposition of windblown sand and conserve sand placed within the fill template. The sand fencing will be constructed of wooden slats, appropriately spaced laterally, and secured with fence wire to wooden posts to form a porous barrier constructed four (4) feet in height above the dune platform. Offset distance at fencing overlap locations vary from 3ft to 8ft, which allows for wildlife movement across the island.

Vegetative planting of the dune and marsh is a vital component of barrier island habitat restoration. All of the Project features include establishment of vegetation along the entire length of the dune and marsh platform at a planting density and composition similar to recent barrier island restoration projects in Louisiana. The entire dune platform will be planted immediately following construction. Vegetative plantings will be a separate contract and will be installed after construction during fall through early spring pending final completion, out of bird nesting season. The marsh will be planted in spring and the dune will be planted fall through early spring.

The vegetative plantings would include a mixture of some or all of the following herbaceous species: Bitter Panicum (Panicum amarum var. amarum ‘Fourchon’), Seashore Paspalum (Paspalum vaginatum ‘Brazoria’), Seacoast Bluestem (Schizachyrium maritimum ‘Timbalier’), Seashore Dropseed (Sporobolus virginicus), Sea Oat (Uniola paniculata ‘Caminada’), Marshhay Cordgrass (Spartina patens ‘Gulf Coast’), and Gulf Cordgrass (Spartina spartinae). Woody species would be planted landward of the restored dune and supratidal back berm area, at a planting density of fifteen (15) percent to mimic the sparsely vegetated native vegetative assembly that typically occurs in this area. Woody species for the dune and supratidal areas would primarily be Matrimony Vine (Lycium barbarum). After construction and consolidation, the newly created marsh platform will be planted with Smooth Cordgrass (Spartina alterniflora var. ‘Vermilion’) and other appropriate species.

3. DESCRIPTION OF STATUS OF SPECIES

The following sections provide the Federal status, species descriptions, and habitat information for the threatened/endangered species and critical habitat found within the Project boundary. The Project boundary refers to Project features on East Timbalier Island, West Belle Pass Headland, borrow and pump-out areas. Much of this information was adapted from the Biological Assessments conducted for the Louisiana Coastal Area Terrebonne Basin Barrier Shoreline Restoration Feasibility Study (LCA TBBSR) (USACE, 2010) and Supplemental Biological Assessment for the Louisiana Island Restoration: Caillou Lake Headlands, Chenier-Ronquille and Shell Island (USFWS, 2014).

1.8Rufa Red Knot

1.8.1Description of the Species

The rufa red knot (Calidris canutus rufa) is a medium-sized shorebird about 9 to 11 inches (in) (23-28 centimeters (cm)) in length with a proportionately small head, small eyes, short neck, and short legs. It has a black bill which is not much longer than head length. Legs are typically dark gray to black, but sometimes greenish in juveniles or older birds in non-breeding plumage (feathers). Because the proposed project areas are not breeding areas, the red knot would primarily be exhibiting non-breeding plumage which is dusky gray above and whitish below. Many individuals, however, would acquire breeding plumage in the action area, prior to and during spring migration (March-May), and may retain breeding plumage during early portions of fall migration (July-September) (Baker et al. 2013). Juveniles resemble non-breeding adults, but the feathers of the scapulars (shoulders) and wing coverts (small feathers covering base of larger feathers) are edged with white and have narrow, dark subterminal bands, giving the feather a scalloped appearance. Adult body mass varies seasonally, with lowest mean mass during early winter (4.4 ounces (oz) [125 grams (g)]) and highest mean values during spring (7.2 oz [205 g]) and fall (6.1 oz [172 g]) migration.

1.8.2Species Habitat and Distribution

The range of the red knot during migration extends along the Atlantic and Gulf of Mexico coasts of North, Central, and South America, from the Canadian arctic to the southernmost extent of South America.

Breeding occurs within the central Canadian high arctic. Red knots generally nest in dry, slightly elevated tundra locations. Red knots are estimated to begin breeding at two years of age and may survive to seven years. Breeding success of High Arctic shorebirds, like red knot, varies dramatically among years in a somewhat cyclical manner. Breeding seems to be affected by two main factors: weather that affects nesting conditions and food availability, and the abundance of arctic lemmings which affects predation rates.

Southward migration from arctic breeding areas begins in mid-July, stopping at various locations along the Atlantic slope to feed and rest. Red knots would generally be expected to “stopover” within the project area from late July through October, then continue their fall migration to their primary wintering grounds, or remain on the Gulf coast for the winter.

For red knots wintering in South America, the birds are present in the South America wintering areas from November through February. Range and distribution during the fall and spring migration and winter in Mexico and Central America are not well known. It is also unknown if segregation of juvenile and adult red knots occurs on the wintering grounds, if juveniles may winter separately from adults, or occur in habitats not used by adults (78 FR 60024).

During the spring migration, red knots begin moving northward along the Atlantic coast of South America in late February or March. The northward migration is very rapid. Red knots complete their pass along the Atlantic coast of the United States from the middle to the end of May. Known spring stopover areas are along coastal Virginia and Delaware Bay in Delaware and New Jersey, where the birds are present in mid-to late May in high abundance (i.e., approximately 90 percent of the entire population may be present in the Delaware Bay in a single day). After a few weeks during the spring stopover on the mid-Atlantic Coast, the red knot may make additional stops in southern Canada and then return to their breeding grounds in the Canadian Artic. Red knots are also commonly found along the northern GOM coast in Texas and Louisiana during spring migration, roughly during April and into early May.

Wintering areas for the red knot include the Atlantic coasts of Argentina and Chile (particularly the island of Tierra del Fuego that spans both countries), the north coast of Brazil (particularly in the State of Maranhao), the Northwest Gulf of Mexico from the Mexican State of Tamaulipas through Texas (particularly at Laguna Madre) to Louisiana, and the Southeast United States from Florida (particularly the central Gulf coast) to North Carolina (78 FR 60024 and references within). Smaller numbers of red knot winter in the Caribbean, and along the central Gulf coast (Alabama, Mississippi), the mid-Atlantic, and the Northeast United States. In the United States, the red knot is found principally in intertidal marine habitats, especially near coastal inlets, estuaries, and bays, or along restinga formations.

Within the United States, red knot migratory and wintering habitats are principally utilized for resting and foraging activities. In the Southeastern United States, red knots commonly forage on bivalves, gastropods, and crustaceans along sandy beaches, tidal mudflats, salt marshes, and peat banks. In Florida, the birds also use mangrove and brackish lagoons. Along the Texas coast, red knots forage on beaches, oyster reefs, and exposed bay bottoms and roost on high sand flats, reefs, and other sites protected from high tides. Coquina clams are a frequent and often important food resource for red knots, and are common along Gulf beaches and in some places occur abundantly.

These data were summarized by Russell (2014) unless otherwise stated. Purrington (2012) notes the species as an uncommon to common migrant on Gulf beaches and uncommon to scarce winter visitor. The birds seem to disappear in the coldest winters, perhaps moving down the Texas coast or even farther south. Most wintering birds have been documented within the Grand Terre/Grand Isle region west to Raccoon Island, Terrebonne Parish (35 on 6 February 2011), but presumably some may winter offshore on the seldom-visited Chandeleur Island chain. A high count of 70 individuals was documented on 6 February 2011, on Timbalier Island. More “normal” winter counts range from 1 to 10 birds.

Wintering birds appear to be largely absent from the southwestern Louisiana beaches where they are regular during spring and fall migration, even occurring occasionally in rice fields and coastal marshes as far inland as the Intracoastal Waterway and Calcasieu Lake.

Red knot numbers increase in April and early May with a peak count documented in southeast Louisiana of 530 individuals on Grand Isle on 1 May 2004. More recently, the Barataria-Terrebonne National Estuary Program (BTNEP) has been recording presence of red knots on 13 miles (21 km) of shoreline at Caminada Headland during bi-monthly wintering shorebird compliance surveys for piping plover (BTNEP, unpublished data). These surveys recorded an average of 11.7 red knots per survey from highly variable sightings; ranging from 0 individuals on numerous occasions to a high of 64 individuals during a single survey in September of 2013. Spring migration banding efforts by BTNEP and their partners have also documented relatively large flocks (100+ or more) of red knots on Grand Isle annually from 2014 through 2016 (unpublished data). The source of these birds is currently unknown but research is underway to determine the migratory patterns of birds observed in Louisiana. See the project specific chapters for red knot use of the project areas.

1.8.3Status and Cause of Decline

The red knot was proposed as a threatened species on September 30, 2013, due to loss of both breeding and nonbreeding habitat; potential for disruption of natural predator cycles on the breeding grounds; reduced prey availability throughout the nonbreeding range; and increasing frequency and severity of asynchronies (“mismatches”) in the timing of the birds’ annual migratory cycle relative to favorable food and weather conditions. On December 11, 2014, the rufa red knot was listed as a threatened species under the Endangered Species Act of 1973, as amended.

Assessing the population size of a wide-ranging migratory species such as the red knot is difficult as counts within their expansive Arctic breeding areas are not feasible. More recently, analysis of multi-year data generated within two key red knot localities (Tierra del Fuego, wintering area and Delaware Bay, migration stopover area) demonstrated roughly a 75 percent decline in species’ population estimates since the 1980s (78 FR 60024 and references within).

A large portion of individual red knot accounts occurring within the fall or spring stopover and/or wintering areas along the Gulf coast has been documented within a centralized database (AKN 2013). The southeastern wintering population (Florida, Georgia, South Carolina, North Carolina, and Virginia) was reported at approximately 7,500 individuals and 4,500 individuals in 2005 and 2006, respectively. Five surveys along the west coast of Florida between 2005 and 2010 indicated an approximate average of 1,432 individuals. Records compiled prior to 1999 indicated the Louisiana coastline supported approximately 2,500 red knots. Red knots have been observed along other Gulf coast States at various locations, though generally in lower numbers (Alabama = 70, Mississippi = 35) across nearly all months of the year (AKN 2013). Red knots in southwest and northwest Florida have been observed utilizing more than one site within a region or sub-region. In the northwest birds during spring and winter moved among the sites at distances of 5 kilometers (km), 23 km, and 27 km (Smith 2010) and birds in the in southwest during the winter moved among sites varying between 0.6 and 12.4 miles (1-20 km) (Schwarzer 2011).

Main threats to the red knot in the United States include: reduced forage base at the Delaware Bay migration stopover area; decreased habitat availability from beach erosion, sea level rise, and shoreline stabilization in Delaware Bay; reduction in or elimination of forage due to shoreline stabilization, hardening, dredging, beach replenishment, and beach nourishment in Massachusetts, North Carolina, and Florida; and beach raking which diminishes red knot habitat suitability. These and other threats in Canada and South America are detailed in the Species Assessment and Listing Priority Assignment Form (USFWS 2011) and the proposed listing rule (78 FR 60024). Unknown threats may occur on the breeding grounds.

1.9Piping Plover

1.9.1Description of the Species

The piping plover (Charadrius melodus) is a small, sand-colored, robin-sized shorebird. Three separate breeding populations have been identified, each with its own recovery criteria: the northern Great Plains (threatened), the Great Lakes (endangered), and the Atlantic Coast (threatened) (USFWS 1988, 1996, 2003).

1.9.2Species Habitat and Distribution

The piping plover ranges from prairie Canada and the Great Plains, along the Great Lakes, and the Atlantic coast and migrates to the southeastern U.S. along the Gulf and Atlantic coasts.

Breeding activity begins in mid-March when birds begin returning from the southern Atlantic and Gulf coasts to their nesting areas (Coutu et al. 1990; Cross 1990; Goldin et al. 1990; MacIvor 1990; Hake 1993). Plovers are known to begin breeding in their first adult year (MacIvor 1990; Haig 1992); however, the percentage of birds that breed in their first adult year is unknown. Piping plovers generally fledge only a single brood per season, but may re-nest several times if previous nests are lost.

Piping plovers migrate to the GOM from each of the three breeding populations to winter (i.e., forage, loaf, other non-breeding activities), spending up to 10 months of their life cycle on their migration and winter grounds, generally July 15 through as late as May 15. Some individuals may remain in the Gulf during one or more summer seasons (i.e., versus returning to breeding areas). The source breeding population of a given wintering individual cannot be determined in the field unless it has been banded or otherwise marked. However, research has demonstrated that the winter ranges of the breeding populations overlap, with the majority of individuals wintering in the project area originating from the northern Great Plains and prairie Canada breeding population (Gratto-Trevor et al. 2012).

Wintering is a particularly critical time in the species’ life cycle due to the energetics involved with migration and preparing for the next breeding season. Behavioral observations of piping plovers on the wintering (non-breeding) grounds suggest that they spend the majority of their time foraging (Nicholls and Baldassarre 1990, Drake 1999a, 1999b). Feeding activities may occur during all hours of the day and night (Staine and Burger 1994, Zonick 1997) and at all stages in the tidal cycle (Goldin 1993, Hoopes 1993). Wintering plovers primarily feed on invertebrates such as polychaete marine worms, various crustaceans, fly larvae, beetles, and occasionally bivalve mollusks (Bent 1929, Nicholls 1989, Zonick and Ryan 1996). They peck these invertebrates on top of the soil or just beneath the surface.

Wintering plovers are dependent on a mosaic of habitat patches and commonly make local movements (i.e., cross-inlet movements) as well as occasional movements of up to 11 miles (18 km) (Maddock et al. 2009) among these patches depending on local weather and tidal conditions for foraging. However, the average distance traveled has been estimated to be only 2.1 miles (3.3 km) (Drake 1999b; Drake et al. 2001). These habitat mosaics used for foraging include moist substrate features such as intertidal portions of ocean beaches, washover areas, mudflats, sand flats, algal flats, shoals, wrack lines, sparse vegetation, shorelines of coastal ponds, lagoons, ephemeral pools, and areas adjacent to salt marshes (USFWS 2001b). Studies from the coastal breeding range have shown that the relative importance of various feeding habitat types may vary by site. Prey items and biomass are more abundant and available to plovers on sound islands and sound beaches than the ocean beach. Intertidal mudflats and/or shallow subtidal grass flats appear to have greater value as foraging habitat than the unvegetated intertidal areas of a flood shoal (Gibbs 1986, Coutu et al. 1990, McConnaughey et al. 1990, Loegering 1992, Goldin 1993, Hoopes 1993, Cohen et al. 2006). Therefore, habitats on the sound sides of inlets and islands, mudflats, and shallow subtidal grass flats are typically considered optimal habitats for plovers, though individuals may use all habitat types.

Wrack is the primary component of roosting habitat for nonbreeding piping plovers. Both old and fresh wrack are used by piping plovers as roosting habitat. Other habitats valuable for roosting include intertidal habitats, backshore (defined as zone of dry sand, shell, cobble, and beach debris from mean high water line up to the toe of the dune), washover areas and ephemeral pools (Lott et al. 2009, Maddock et al. 2009, Smith 2007, Drake 1999b).

1.9.3Status and Cause of Decline

On January 10, 1986, the piping plover was listed as endangered in the Great Lakes watershed and threatened elsewhere within its range, including migratory routes outside of the Great Lakes watershed and wintering grounds (50 FR 50726). On July 10, 2001, NMFS designated critical habitat for wintering piping plovers (Federal Register Volume 66, No. 132).

Critical habitat for piping plover in Louisiana encompassed 24,950 acres (ac) along 342.5 miles of shoreline at the time of designation. The critical habitat designated in the Project area includes the West Bell Pass headland, but does not include East Timbalier Island and is described in detail as follows:

• Unit LA-5: Timbalier Island to East Grand Terre Island. 5,735 ac (2,321 ha) in Terrebonne, Lafourche, Jefferson, and Plaquemines Parishes (Figure 3-1).
Description of Unit LA-5

Timbalier Island to East Grand Terre Island. 5,735 ac (2,321 ha) in Terrebonne, Lafourche, Jefferson, and Plaquemines Parishes. This unit includes: all of Timbalier Island where primary constituent elements occur to the Mean Lower Low Water (MLLW), all of Belle Pass West [the “peninsula” extending north/northwest approximately 4.8 km (3.0 mi) from the west side of Belle Pass] where primary constituent elements occur to MLLW; the Gulf shoreline extending approximately 11 km (6.8 mi) east from the east side of Belle Pass bounded on the seaward side by MLLW and on the landward side to where densely vegetated habitat, not used by the piping plover, begins and where the constituent elements no longer occur; all of Elmers Island peninsula where primary constituent elements occur to MLLW and the Gulf shoreline from Elmers Island to approximately 0.9 km (0.56 mi) west of Bayou Thunder Von Tranc bounded on the seaward side by MLLW and on the landward side to where densely vegetated habitat, not used by the piping plover, begins and where the constituent elements no longer occur; the Gulf shoreline of Grand Isle from the Gulf side of the hurricane protection levee to MLLW; and all of East Grand Terre Island where primary constituent elements occur to the MLLW (http://fws.gov/plover/finalchmaps/Louisiana.pdf).

Directory: East%20Timbalier

Download 6.17 Mb.

Share with your friends: