4 AFFECTED ENVIRONMENT 4.1 REGIONAL PLANNING AREAS on the OCS the Three Outer Continental Shelf
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Alternative Energy Programmatic EIS 4-1 October 2007 4 AFFECTED ENVIRONMENT 4.1 REGIONAL PLANNING AREAS ON THE OCS The three Outer Continental Shelf (OCS) regions analyzed for potential alternative energy development in this programmatic Environmental Impact Statement (EIS) are the Atlantic, Gulf of Mexico (GOM), and Pacific regions as shown in Figure 4.1-1 (alternative energy developments in the Alaska and Hawaii regions are not considered at this time). The Atlantic region extends from Maine southward through the Straits of Florida; the Gulf of Mexico region includes the area off the western coast of Florida through Texas; and the Pacific region extends from the southern coast of California northward to the border of Washington State with Canada. The extent of Federal (U.S. Department of the Interior [USDOI]/Minerals Management Service [MMS]) jurisdiction of the OCS is defined under principals of international law, such that jurisdiction extends from the seaward extent of State jurisdiction out about 200 nautical miles (mi) (230 mi; 370 kilometers [km]) into the ocean (there are exceptions to this for instances where the OCS width is greater than 200 nautical mi). State jurisdiction generally extends from the shore out to 3 nautical mi (3.5 mi; 5.6 km), except for Texas and the Gulf Coast of Florida, where State jurisdiction extends to 9 nautical mi (10.4 mi; 16.7 km). Regional MMS offices1 conduct oil and gas leasing on the OCS in regional planning areas, and they also permit and inspect oil and gas facilities to ensure operational safety and protection of the marine, coastal, and human environment. The MMS is also responsible for other minerals management offshore, which currently involves the use of sand and gravel for coastal restoration projects. The Atlantic region is subdivided into four planning areas, which include the North Atlantic (from Maine south to include the New Jersey coast), the Mid-Atlantic (from Delaware south to include the coast of North Carolina), the South Atlantic (from the coast of South Carolina south to approximately Cape Canaveral, Florida), and the Straits of Florida (extending from around the southern tip of Florida about 200 km [125 mi] into the GOM). The MMS GOM regional office conducts all leasing and resource management activities for the Atlantic region. Currently, there are no active oil and gas leases on the Atlantic region OCS (USDOI/MMS 2006a). Historically there have been 433 leased blocks, with more than half of these in the Mid- Atlantic planning area. Between 1996 and 2006, there were 16 coastal restoration projects in the Atlantic region, providing about 15 million cubic meters (m3) (20 million cubic yards [yd3]) of OCS sand for beach restoration. The GOM region is divided into three planning areas, including the Western GOM (includes the coast of Texas), the central GOM (includes the coasts of Louisiana, Mississippi, and Alabama), and the Eastern GOM (includes the western coast of Florida). There are about 42 million acres (17 million hectares [ha]) in the GOM region under oil and gas leases. This part 1 The MMS has three regional offices: Gulf of Mexico Offshore Region, Pacific Offshore Region, and the Alaska Offshore Region. The resources in the Atlantic region are managed by the Gulf of Mexico Offshore Regional office. A lternative Energy Programmatic EIS 4-2 October 200 FIGURE 4.1-1 The Atlantic, Gulf of Mexico, and Pacific Regional Planning Areas on the Outer Continental Shelf 7 Alternative Energy Programmatic EIS 4-3 October 2007 of the U.S. OCS is a major energy production area, generating 23% of total U.S. natural gas production and 30% of total U.S. oil production (USDOI/MMS 2006b). GOM production from January through June 2006 averaged about 1 million barrels/day (bpd) for oil and 6.9 billion cubic feet/day (bcf/d) for gas (USDOI/MMS 2006b). There are currently about 4,000 producing platforms on the GOM OCS; about half of these are considered major platforms and about one quarter are manned by personnel. It is estimated that there are more than 55,000 petroleum- related jobs in the GOM. Recent discoveries have mainly been in deep water (i.e., greater than 300 meters [m] [1,000 feet (ft)]). Due to administrative deferrals and congressional moratoria, relatively fewer leases (146) exist in the Eastern GOM than in the other two planning areas. Many studies are underway on the use of OCS sand and gravel for beach restoration in the GOM, especially since the 2005 hurricane season, which caused extensive beach erosion. The Louisiana Coastal Area Ecosystem Restoration Study estimates that about 46 million m3 (60 million yd3) of OCS sand from Trinity Shoal, Ship Shoal, and other sites will be needed for barrier island and shoreline restoration (USDOI/MMS 2006b). The Pacific region is divided into four planning areas: the South, Central, and Northern California areas and the Washington/Oregon planning area. The leased area in this region encompasses about 162,000 ha (400,000 acres), in which 79 leases are active (USDOI/MMS 2006c). There have been approximately 1,300 oil and gas wells drilled. Platform depths range from 29 m (95 ft) to 366 m (1,200 ft). Although no shoreline restoration projects have occurred in the Pacific region, the MMS has funded many studies of the potential environmental impact of sand and gravel dredging in all of the planning areas. The affected environments along the Atlantic, Gulf of Mexico, and Pacific regions are described in Sections 4.2, 4.3, and 4.4, respectively. As indicated above, the OCS extends from about 3 nautical mi (3.5 statute mi; 5.6 km) off the coast (9 nautical mi [10 mi; 17 km] from the Texas coastline and the Gulf Coast of Florida) to about 200 nautical mi (230 mi; 370 km) into the ocean. For some resource areas, such as transportation, electromagnetic fields, coastal habitats, socioeconomic resources, land use, visual resources, and tourism and recreation, the affected environment would include part of the area covered by the State waters between the OCS and the coastline and some areas on land. The MMS expects that the applications to be received over the next 5 to 7 years for the development of alternative energy on the OCS will be in water depths of 100 m (330 ft) or less for wind and wave technologies and 500 m for marine current technologies. As a result, for most of the resource areas, the affected environment from these applications would not extend all the way to 200 nautical mi (230 mi; 370 km) into the ocean and, in fact, would cover only part of the OCS. In the following sections, these variations in the extent of the affected environment are discussed under individual resources as appropriate. The potential impacts from the expected alternative energy and alternate use program activities over the same period are described in Chapters 5, 6, and 7. Alternative Energy Programmatic EIS 4-4 October 2007 4.2 ATLANTIC REGION 4.2.1 Geology 4.2.1.1 General Description and Physiography 4.2.1.1.1 North to Mid-Atlantic Region. The North to Mid-Atlantic region is situated on a broad shelf with a width generally greater than 120 km (75 mi) (Figure 4.2.1-1). The 100-m (330-ft) water-depth contour generally coincides with the extent of the shelf in this area. The shelf is overlain by a mantle of sand, ranging in thickness from 20 m (65 ft) on the Mid-Atlantic portion of the shelf to 40 m (130 ft) on the North Atlantic portion. Linear sand ridges are also characteristic of the continental shelf in this region. Georges Bank, a broad and shallow platform on the shelf (with an area of about 67,000 km2 [26,000 mi2]), lies to the southeast of the Gulf of Maine. The Georges Shoals is a shallow area on the bank, with a depth of less than 20 m (65 ft). Georges Bank is separated from the rest of the shelf by two shallow channels: the Northeast Channel to the northeast, providing entrance to the Gulf of Maine, and the Great South Channel to the southwest, separating the bank from Nantucket Shoals. The eastern and southern sides of Georges Bank, at depths of 140 to 160 m (460 to 525 ft) along the shelf edge, are incised by several submarine canyons, gullies, and ravines. The New England Seamount chain lies to the east of Georges Bank (Scholle and Wenkam 1982; Shor and McClennen 1988). The continental slope here is highly dissected by deep canyons and valleys. Submarine canyons in the North Atlantic region include (from northeast to southwest): Corsair, Lydonia, Oceanographer, Hudson, Wilmington, Baltimore, Washington, Norfolk, Pamlico, and Hatteras. Sediments on the slope are highly variable, but consist mainly of sandy silts on the upper slope and silts and clays on the lower slope (McGregor 1983). The geological distinction between the North and Mid-Atlantic areas is based on the presence of two deep sedimentary basins that underlie the continental margin: the Georges Bank Basin to the north and the Baltimore Canyon Trough to the south (Figure 4.2.1-2). The elongate, northeast-trending basins are characterized by extensional tectonic features (horst and graben) related to the rifting between North America and Africa during the Triassic (about 200 million years ago). Both basins thicken seaward and have no physiographic expression. Georges Bank Basin is a collection of smaller basins with a thickness of greater than 10 km (6.2 mi); it merges with the Scotian Basin beneath the Canadian Shelf to the north.