United states department of interior bureau of ocean energy management
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- 1.4Restoration Areas
1.3Previous NEPA DocumentsCoastal restoration projects have previously been undertaken on East Timbalier in 2000 (Picciola 2000) and adjacent to the proposed project features on West Belle Pass Barrier Headland in 2011 (CPE, 2009 and CPE, 2013); both projects were funded and administered though the Coastal Wetlands Planning, Protection and Restoration Act 9CWPPRA) Program. The previous East Timbalier Island Sediment Restoration (TE-25 and TE-30) and West Belle Pass Barrier Headland Restoration (TE-52) projects’ Federal permit number are EC-19-980-079 and MVN-2010-01901-WOO, respectively. An Environmental Assessment (EA) was prepared for TE-25/30 and concluded there would be no significant environment impacts as a result of the project. A Section 7 consultation was completed with the USFWS on March 26, 1998, that concurred with the determination of not likely to impact listed species. Additionally, consultation with NMFS was completed on May 14, 1998 and concluded that fishery resource habitat may be improved as a result of the restoration project and turtle species and Gulf sturgeon may eventually benefit from the restoration, therefore the proposed action was not likely to adversely affect the listed species. Likewise, an EA was prepared for TE-52 and concluded there would be no significant environment impacts as a result of the project. A Section 7 consultation was completed with the USFWS on December 1, 2009, that concurred with the determination of not likely to impact listed species, including piping plover. Additionally, an informal consultation Section 7 with NMFS was completed on May 27, 2010 that concurred and the proposed action was not likely to adversely affect sea turtles nor Essential Fish Habitat (EFH).
1.4.1East Timbalier Island Restoration AreaThe East Timbalier Island restoration template extends the length of the island and includes the construction of beach, dune, and two marsh components (Figure 2-2). These features on East Timbalier Island will result in the restoration of a total of approximately 516 acres of dune habitat (elevation > +5.0 ft NAVD88), supratidal habitat (elevation between +2.0 ft and +5.0 NAVD88), and intertidal marsh habitat (elevations between 0.0 ft and +2.0 ft NAVD88). The East Timbalier Island beach and dune features are approximately 13,600 linear feet long and requires placement of approximately 6.6 MCY of sand. The dune will be constructed at a target elevation of +7.5 ft NAVD88, with fore and back-slopes of 1V:25H and a width of 100 ft at the crest, Figure 2-3. The target elevation of the beach will be +5.0 ft NAVD88, with a slope of 1V:25H from the beach berm crest extending seaward to the intersection with the existing grade, and a width ranging from 170 to 400 ft. Assuming a 1.3:1 cut to fill ratio, and being conservative in the Preliminary Design Phase, the recommended cut volume from South Pelto and/or Ship Shoal requirements for the sand source to construct the beach and dune features is approximately 8.6 MCY. The two East Timbalier Island marsh components are approximately 6,800 linear feet in combined length extending from Stations 110+00 to 140+00 and from Stations 190+00 to 220+00, north of the beach and dune, and requires placement of approximately 1.3 MCY of mixed sediments to create the marsh platform at a target elevation of +3.0 ft NAVD88. Assuming a 1.6:1 cut to fill ratio and being conservative in the Preliminary Design Phase, the recommended cut volume requirements for the mixed sediments source for the marsh platform were calculated at 2.1 MCY. The East Timbalier Island marsh containment dikes will be constructed from sediment dredged from the Ship Shoal and/or South Pelto Borrow Areas requiring approximately 0.45 MCY in place and a cut volume of approximately 0.6 MCY. The marsh containment dike dimensions are +5.3 ft NAVD88 crest elevation, 30 ft crest width, with 1V:25H side slopes.  Directory: East%20Timbalier Download 6.17 Mb. Share with your friends:
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