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1 Introduction Offshore drilling for of! and gas has been conducted since the beginning of the century, and oil and gas under the seabed continue to be an important part of the energy resources of the United States. The need to balance the value of these resources against the potential for environmental damage has become increasingly recognized in federal laws and national debate over energy. Until 1969, potential environmental damage from outer continental shelf (OCS) oil and gas activities was mostly a local concern in the affected states. Environmental concerns were brought to national attention by oil-spill damage resulting from a major blowout at a Union Oil platform in the Santa Barbara Channel in January 1969 (Congressional and Administrative News of the U.S. Code, 1978~. That oil spill covered 660 square miles, including 150 miles of coastline (Cicin-Sain, 1986~. Other accidents involving oil and gas have added to environmental concerns, even though they have not involved the U.S. OCS. Two accidents widely noticed in the United States were the blowout of the Mexican offshore well IXTOC I on June 3,1979, which released over 150 million gallons (500,000 tons) of oil as well as natural gas the largest accidental oil spill in history (NRC, 1983) and the grounding of the tanker Exxon Valdez on March 24, 1989, which released approximately 11 million gallons of North Slope crude oil into Alaska's Prince William Sound. Even though the Exxon Valdez accident did not involve OCS oil, it is clear that it has affected debate on the production of OCS oil. The value of the petroleum resource is large. From 1954 through 1988, the last year for which statistics have been published, OCS oil and gas development provided about 7h of total domestic oil production, about 13Yo of domestic natural gas, and more than $90 billion in revenue from cash bonuses, lease rental payments, and royalties on produced of} and gas. In 1988 alone, the OCS provided approximately 10.89/0 of domestically produced oil, 24.6% of domestic natural gas, and over $3 billion in revenue to the government (U.S. DOI,1989~. Thus, balancing the value of the resource against environmental concerns is an important concern. OlTrER CONTINENTAL SHELF ACTIVITIES Management of OCS Activities OCS leasing is managed by the Minerals Management Service (MMS) of the Department of the Interior (DOI). MMS was formed in 1982 to consolidate responsibility for offshore oil and gas development in one agency. It includes some functions and personnel previously in the Bureau of Land Management (BLM) and the U.S. Geological Survey (USGS). Federal responsibility for development of mineral resources and conservation of natural resources on the OCS was established by the Outer Continental Shelf Lands Act of 1953 as amended in 1978 (OCSLAA) (43 U.S.C.1331-1356,1801-1866) and the Submerged Lands Act of 1953 (43 U.S.C. 1301-1315~. 7

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8 PHYSICAL OCEANOGRAPHY OF THE U.S. OUTER CONTINENTAL SHELF In 1974, as part of a strategy to deal with the nation's energy problems following the Arab oil embargo, former President Richard Nixon directed the Secretary of the Interior to increase the amount of acreage leased. Congress was also concerned, however, that federal administration of the leasing program and regulation of OCS development was a closed decision-making process involving the Secretary of the Interior and industry (Congressional and Administrative News of the U.S. Code, 1978~. In 197S, when OCSLAA was passed, Congress expected that offshore production would provide the largest domestic source of oil and gas into the 1990s (Congressional and Administrative News of the U.S. Code, 1978~. One purpose of the amendments was to provide a statutory mechanism to open decision making to a wide variety of views and to increase public confidence in this government activity (Congressional and Administrative News of the U.S. Code, 1978~. The OCS lease-sale schedule is established in accordance with a 5-year plan indicating the size, timing, and location of proposed leasing activities. The plan is developed in a 2-year process that includes consultation with coastal states and other federal agencies and an opportunity for public comment. Beginning in 1983, lease sales were offered on an area-wide basis instead of for selected tracts so that the number of blocks and leases was increased and more exploratory wells were encouraged in frontier areas, such as areas of deep water. (The areawide leasing process has been modified in the current five-year plan to a "focused" leasing process that gives primary consideration to promising acreage.) The current plan, effective from mid-1987 to mid-1992, calls for one sale every 3 years in 21 of the 26 OCS planning areas (see Figs. 1 and 2), except in the Gulf of Mexico, where sales are scheduled annually. Sales in several environmentally sensitive subareas have been deferred indefinitely (U.S. DOI, 1987a). Extent of the Leasing Program Between 1954 and 1988 there were 100 lease sales offering 127,585 tracts that included 695,936,201 acres in the four OCS regions-Alaska, the Atlantic, the Gulf of Mexico, and the Pacific. Only 10,380 (~.1%) of those tracts, which included 53,270,423 acres (i.e., 7.7% of the acreage offered), were actually leased. Table 1 provides a regional breakdown of lease offerings and sales between 1954 and 1988. Of 5,818 leases active in 198S, 1,647 (28%, totaling 7,691,964-acres) were producing. To date, all producing leases have been in California and the Gulf of Mexico; although some in Alaska have proven reserves. Production first began in the OCS in the Gulf of Mexico region in 1954. California OCS wells did not begin to produce until 1968. Tracts on federal lands in the Alaska and AtIantic regions were first leased in 1976 but to date have not produced. However, there has been considerable production in state tracts in Alaska as well as ih California and the Gulf of Mexico. Table 2 shows, by region, the number of leases active in 1988. Through 1988, 4,235 platforms had been built and 576 had been removed, leaving 3,659 in place (U.S. DOI, 1989~. Environmental Concerns Resulting from OC:i Activities The potential impacts of oil spills resulting from OCS development and production on resources, such as fisheries and endangered species, have caused environmental concern. Other sources of potentially adverse impacts associated with OCS development include the discharge of produced water and drilling muds and chronic loss of oil at the drilling sites. Seismic surveys (conducted in the exploratory phase), platforms, and pipelines may interfere with commercial, recreational, and subsistence fishing activities. In addition, potentially adverse socioeconomic impacts are also associated with the construction of onshore support facilities (NRC, 1978, U.S. DOI, 1987a). The potential for long-term, chronic environmental effects is also a source of concern (Table 3~. The effects of oil spills and drilling mud discharges have been the subject of previous NRC reviews (NRC, 1975; 1983; 1985~. Oil discharged from OCS operations has been estimated to contribute approximately 1% of oil inputs in the oceans worldwide from all sources (NRC, 1985), but is nevertheless a major source of public concern. Total spillage and seepage for

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INTRODUCTION ~o:~/' it'- job. I'm it\ . . FIGURE 1 Outer Continental Shelf planning areas (Alaska). Source: U.S. DOI, 1987a. . 'I y/' 12" /`' 7 T ~t ~ ~ l ~ \ Ski .1 / / \ _ / OCS PLANNING AREAS '~ 'I it/ ~ ~ 'it `~ 1 ~ 2 8-C4~071~ so / / 7~ 1 _ ~ ~ ~ 4: - )~5 1 20- 1 te. , lo. am. 1 OS. 1 00. ~GULF OF MEXICO ~l see so. 88. so. 76. FIGURE 2 Outer Continental Shelf planning areas (contiguous United States). Source: U.S. DOI, 1987a. 9

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10 TABLE 1 Lease Offerings and Sales, 1954-1988 PHYSICAL OCEANOGRAPHY OF THE U.S. OUTER CONTINENTAL SHELF Number Leases OfferedLeases IssuedLeased Percentage Region of Sales TractsAcresTracts Acres Tracts Acres Alaska 15 17,63898,013,7641,481 8,181,465 8.4 8.3 Atlantic 8 9,16051,520,602410 2,334,205 4.5 4.5 Gulf of 66 98,885536,578,4408,019 40,214,741 8.1 7.5 Mexico Pacific 11 1,9039,823,395470 2,540,012 24.7 25.9 Total 100 127,586695,936,20110,380 53,270,423 8.1 7.7 Source: U.S. DOI, 1989. TABLE 2 Active Leases, 1988 Percentage of Percentage of RegionActive Leases Active Leases Acres Leased Acres Leased Alaska1,000 17.2 5,495,059 18.6 Atlantic74 1.3 421,296 1.4 Gulf of Mexico4,609 79.2 22,967,196 77.6 Pacific135 2.3 700,200 2.4 Total5,818 100.0 29,583,751 100.0 Source: U.S. DOI, 1989. the Gulf of Mexico and Pacific regions (1970-1988) was estimated at nearly 205,000 barrels (Table 4) (U.S. DOI, 1989~. Table 5 provides the location and type of accident for reported spills of 1,000 barrels or more from 1964 to 1988 all but one were in the Gulf of Mexico. Other sources of of! in the marine environment include natural sources (e.g., marine seeps and sediment erosion), transportation (including tanker operations, dry-docking, marine terminals, bilge and fuel oils, tanker and nontanker accidents), atmospheric deposition, and municipal wastes (refineries, nonrefining industrial wastes, urban runoff, river runoff, and ocean dumping). In 1985, petroleum inputs to the ocean from all sources were estimated to total between 1.7 and 8.S million metric tons (12.S to 65 million barrels). The most likely figure was estimated to be 3.2 metric tons (23.6 million barrels) (NRC, 1985~. MMS'S ENVIRONMENTAL STUDIES PROGRAM Mandate Under OCSLAA (43 U.S.C. Sec. 1344), MMS must manage the oil and gas leasing program with consideration for the economic, social, and environmental values of both renewable and nonrenewable resources in the OCS; the marine, coastal, and human environments that could be affected; the laws, goals, and policies of affected states; and the equitable sharing of developmental benefits and environmental risks among the various regions. Timing and location of leasing must be selected, to the maximum extent practicable, to balance the potential for

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INTRODUCTION TABLE 3 Major Activities in the Development of an Offshore Oil and Gas Field and Their Potential Effects on Marine and Coastal Environments Activities Potential Effects Evaluation Seismic surveying Exploration Rig fabrication Rig emplacement Drilling Routine rig operations Rig servicing Development and production Platform fabrication Platform installation Drilling Completion Platform servicing Separation of oil and gas from water Fabrication of storage facilities and pipelines Offshore emplacement of storage and pipelines Transfer to tankers and barges Construction of on-shore facilities for transportation and storage Pipeline operations Refining Construction and expansion Operations 11 Noise effects on fishes and mammals Dredging and filling of coastal habitats (mostly overseas) Seabed disturbance due to anchoring Discharge of drilling fluids and cuttings; risk of blowouts Deck drainage and sanitary wastes Discharges from support vessels and coastal port development I'd use conflicts and increased channelization in heavily developed areas Coastal navigation channels; seabed disturbance resulting from placement and subsequent presence of platform Larger and more heavily concentrated discharges of drilling fluids and cuttings; risk of blowouts Increased risk of oil spills Dredges and coastal port development; discharges from vessels Chronic discharges of petroleum and other pollutants Coastal use conflicts Seabed disturbances; effects of structures Lncreased risk of oil spills; acute and chronic inputs of petroleum Coastal use conflicts; alterations of wetlands . . in pipe 1ne carry firs Oil spills; chronic leaks Coastal use conflicts Increased pollutant loading; depends on regional demands, imports, etc. Source: Neff et al., 1987. environmental damage and for adverse impact on the coastal environment with the- potential for discovery of oil and gas. To balance the benefits of the leasing program with environmental concerns, MMS must conduct studies to develop information needed for "the assessment and management of environmental impacts on the human, marine, and coastal environments of the OCS and the coastal areas that may be affected by oil and gas development" in the proposed leasing area

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12 PHYSICAL OCEANOGRAPHY OF THE U.S. OUTER CONTINENTAL SHELF TABLE 4 Crude Oil and- Condensate Spills and Seeps of 1 Barrel or More from Offshore Wells on Federal Leases, 1970-1988 Gulf of Mexico OCS Pacific OCS Number of SpillsTotal Number of SpillsTotalTotal 1-50 More than Spillage 1-50 More Man Spillage Spillage YearBbls. 50 Bbls. in Bbls. Bbls. 50 Bbls. in Bbls. in Bbls. 1970 8 5 , 83,894 0 0 0 83,894 1971 267 7 2,446 0 0 0 2,446 1972 203 1 997 0 0 0 997 1973 178 5 23,125 0 0 0 23,125 1974 80 7 24,453 0 0 0 24,453 1975 109 2 761 0 0 0 761 1976 66 A 5,103 1 0 2 5,105 1977 71 3 1,087 1 0 4 1,091 1978 79 3 1,528 0 0 0 1,528 1979 114 4 2,700 1 0 2 2,702 1980 50 9 2,922 1 0 5 2,927 1981 65 5 5,793 9 0 73 5,866 1982 70 3 1,174 1 0 3 1,177a 1983 91 9 2,552 2 0 4 2,556b 1984 59 1 380 3 0 36 416a 1985 66 5 1,613 1 0 5 1,618a 1986 40 2 356 2 0 11 367 1987 34 1 232 2 0 10 242 1988 29 3 15,285 1 0 2 15,287 Total 1679 79 176,401 25 0 157 176,558 NOTE: These figures do not include natural seepage. Natural seepage in the Santa Barbara Channel is estimated at 40~70 barrels daily (14,600-244,500 barrels yearly) from more than 2,000 seeps. aThese totals include spills for the Alaska OCS: 1982, 1 spill of 19 barrels; 1984, 1 spill of 2 barrels; 1985, 1 spill of 2 barrels; and 1988, 1 spill of 5 barrels. This total includes 2 spills totaling 24 barrels on the Atlantic OCS in 1983. Source: U.S. DOI, 1989. ~. ~ . ~ ~ a . . ~e (43 U.S.C. Sec. 1346 (a)(l)~. Specifically, MMS must predict impacts on the marine biota that could result from chronic low-level pollution or large oil spills associated with OCS production or trom the Introduction of argot cuttings and ring muds in the area and impacts of offshore development on the affected coastal areas (43 U.S.C. Sec. 1346 A. MMS must also conduct studies necessary for monitoring the human, marine, and coastal environments of leased areas "in a manner designed to provide time-series and ciata-trend information which can be used for comparison with any previously collected data for the purpose of identifying any significant changes in the quality and productivity of such environments, for establishing trends in the areas studied and monitored, and for designing experiments to identify the causes of such changes" (43 U.S.C. Sec. 1346 (b)). in addition, the Secretary must "submit to the Congress and make available to the general public an assessment of the cumulative effect of activities conducted under this subchapter on the

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INTRODUCTION TABLE 5 Crude Oil and Condensate Spills of 1,000 Barrels or More From Offshore Wells on Federal Cases, 1964-1988 13 l Year Location Type of AccidentNumber of Barrels Spilled 1964 Eugene Island Freighter struck platform2,559 1964 Eugene Island Platform in hurricane5,180 1964 Ship Shoal Platform in hurricane5,100 1964 Ship Shoal Platform in hurricane1,589 1965 Ship Shoal Well blowout1,688 1967 West Delta Anchor damage to pipeline160,638 1968 South Timbalier Anchor damage to pipeline6,000 1969 Santa Barbara Channel Well blowout77,000 1969 Main Pass Anchor damage to pipeline30,000 1969 Ship Shoal Ship struck platform in storm2,500 1970 Main Pass Well blowout30,000 1970 South Timbalier Well blowout53,000 1973 West Delta Structural failure/tank rupture9,935 1973 South Pelto Storage barge sank7,000 1973 West Delta Pipeline corrosion5,000 1974 Eugene Island Anchor damage to pipeline19,833 1974 Main Pass Hurricane damage to pipeline3,500 1976 Eugene Island Shrimp trawl damage to pipeline4,000 1979 Main Pass Vessel collided with se~submersible1,500 1980 High Island Pump failure, tank spill1,456 1981 South Pass Anchor damage to pipeline5,100 1988 Galveston Anchor damage to pipeline14,944 Source: U.S. DOI, 1989. human, marine, and coastal environments" (43 U.S.C. Sec. 1346 belt. Although such a report obviously should make use of information generated by the Branch of Environmental Studies (BES), the report is prepared by another branch of MMS. Under the same section, the Secretary must also establish procedures for the conduct of the required studies. OCSLAA (43 U.S.C. 1334 Back also requires the Secretary to regulate OCS activities to ensure that they do not prevent the attainment of National Ambient Air Quality Standards. The Secretary must then use information prepared under these sections to support leasing decisions, promulgate regulations, set lease terms, and establish operating procedures (Congressional and Administrative News of the U.S. Code, 1978; 43 U.S.C. Sec. 1346 (ad. Environmental studies information is used to support permitting decisions as well. Separate permits are required prior to conducting geological and geophysical surveys, exploration, development, and production. Exploration, development, and production plans must be submitted to MMS together with an environmental report and a certificate of consistency with state coastal zone management plans from the affected coastal states. The information is also used as the basis for ensuring compliance with other applicable environmental laws such as the National Environmental Policy Act (NEPA) (42 U.S.C. 4321-4347~. NEPA requires federal agencies to "utilize a systematic and inter-disciplinary approach which will insure the integrated use of natural and social sciences and the environmental design arts in planning and in decision making which may have an impact on man's environment" and to prepare environmental impact statements on the basis of such information prior to major federal actions. Other environmental laws applicable to OCS activities include the Endangered Species Act of 1973 (16 U.S.C. 1531-1543, 50 CFR 17) and the Marine

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14 PHYSICAL OCEANOGRAPHY OF TlIE U.S. OUTER CONTINENTAL SHELF Mammal Protection Act of 1972 (16 U.S.C. 1361-1407, 50 CFR 216), which require MMS to consult with the Fish and Wildlife Service and the National Marine Fisheries Service to ensure that OCS activities do not cause significant harm to marine mammals and endangered species or destroy their habitat. The Coastal Zone Management Act (16 U.S.C. 1451-1464; P.L. 92-583), the Federal Water Pollution Control Act Amendments of 1972 (33 U.S.C. 1251-1375, P.L. 92-500), the Alaska National Interest Lands Conservation Act (16 U.S.C. 3101-3233; P.L. 96-487), the National Historic Preservation Act (16 U.S.C. 470-470w6; P.L. 89-665), and the Marine Protection, Research and Sanctuaries Act of 1972 (33 U.S.C. 1401-1445; P.L. 92-352) also affect the offshore leasing process. History of the Environmental Studies Program The ESP was established in 1973, in large part to comply with the requirements of NEPA. Since its inception, when it was administered by the BLM, through 1989, the ESP has invested over $478 million in a wide variety of studies. Funding for the program has averaged about $30 million per year but has recently declined to approximately $20 million per year. Most studies are performed by contractors to the agency (U.S. DOI, 198Sa). MMS's Branch of Environmental Studies (BES) in Washington, D.C., coordinates the environmental studies programs of the four regional offices in Alaska, the Pacific, the Gulf of Mexico, and the Atlantic. The four regional offices (in Anchorage, Los Angeles, New Orleans, and Reston, Virginia) are responsible for defining and contracting most of the studies. MMS's ESP directs and funds one of the largest mission-oriented oceanographic research programs in the federal government (LaBelle and Anderson, 1985~. Physical oceanography studies have accounted for approximately 22% of the ESP budget and over $7 million a year for a total of over $105 million through 1988. Table 6 shows the amount of funding for physical oceanographic studies by region. For a regional listing of all physical oceanographic studies, see Appendix C. TABLE 6 Cumulative Funding for Physical Oceanography Studies by Region, 1973-1988 Region Funding in Dollars Alaska Atlantic Gulf of Mexico Pacific Washington, D.C. Total 44,856,370 27,493,347 9,348,651 19,394,651 4,202,784 105,295,803 Source: Compiled by the Physical Oceanography Panel from information provided by the ESP. From 1974 through 1977, descriptive baseline studies were conducted in each OCS region where industry expressed an interest in leasing. According to MMS, these were large-scale, multidisciplinary studies designed to provide decision makers with a baseline of the geological, physical, biological, and chemical characteristics of the proposed leasing areas (U.S. DOI, l9X7b). These studies were intended to be used as a reference standard to evaluate the impact of OCS oil and gas operations. An NRC review recommended that the ESP stop supporting descriptive baseline studies, because they did not provide any basis for distinguishing natural variability from changes caused by OCS operations (NRC, 1978~. The NRC recommended that the ESP focus on the prediction of impacts from OCS operations and design specific experiments to "establish the vulnerability of key species or communities." That report also questioned "the capacity of the [physical] oceanographic community to use the data being collected to provide

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INTRODUCTION 15 descriptions of the environment more useful for regulatory management of OCS oil and gas operations than those using extant data" except in some areas with very limited existing data. In response to that review, the ESP was restructured in late 1978 to provide more immediately usable results for leasing and management decisions and to provide a framework for establishing study priorities (U.S. DOI, 1987b). Under the mandate to establish procedures for conducting environmental studies, guidance was developed by an OCS ad hoc advisory committee and published in "Study Design for Resource Management Decisions: OCS Oil and Gas Development and the Environment" (U.S. DOI, 1978~; it was adopted by the OCS Advisory Board on April 29, 1978. The guidance document requires identification of management decisions and development of studies to provide the information needed for making those decisions. The national OCS Advisory Board was established by the Secretary of the Interior in 1975 to provide guidance and recommendations on the leasing and development process, to receive comments and recommendations from state officials and other interested parties, and to provide a forum for discussion among the federal agencies involved. The Advisory Board consists of a policy committee, a scientific committee (SC), and a regional technical working group (RTWG) for each region (except the Atlantic, which, because it has 14 coastal states, has three RTWGs). The Advisory Board reviews political, scientific, and technical aspects of OCS development and attempts to balance state, local, federal, public, and private interests. The SC was established specifically to provide guidance and to review the ESP. The RTWGs make recommendations pertaining to the entire leasing and development process (including the ESP) (U.S. DOI, 1987c) (see Fig. 3~. OCS ADVISORY BOARD Chairperson-Chairperson. Policy Committee Vice cha,rperson-V'ce chairperson, Policy Committee POLICY COMMITTEE Elected chairperson and vice chairperson Nonvoting Ex-officio members EPA Dept. of State Dept. of Commerce DOD DOT DOE DOI Assistant Secretaries with mission responsi bil~t~es. Representatives from each coastal State. Pennsylvania. And Hawaii I USCG I EPA l DOD U p to 1 2 discretionary NOAA appointments from l MMS private sectors REGIONAL TECHNICAL WORKING GROUPS Cochaired by Regional Director. MMS and Elected State Member Nonvoting Ex-officio members Representatives from each State in Region At least 3 but not more than 44 discretionary appointments from the private and public sectors FIGURE 3 Outer Continental Shelf Advisory Board organizational chart. Source: U.S. DOI, 1987c. SCIENTIFIC COMMITTEE Elected chairperson and vice chairperson community 10-15 appointments from the scientific

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16 PHYSICAL OCEANOGRAPHY OF THE U.S. OUTER CONTINENTAL SHELF The stated goals of the ESP are to 1. Provide information on the status of the environment that can be used to predict the impacts of OCS oil and gas development; 2. Provide information on the ways and extent to which OCS development can potentially affect the human, marine, biological, and coastal environments; 3. Ensure that information already available or being collected under the program is in a form that can be used in the decision-making process associated with a specific leasing action or with longer-term OCS minerals management responsibilities; and 4. Provide a basis for future environmental monitoring of OCS operations, including assessments of short-term and long-term impacts attributable to the OCS oil and gas program (Aurand, 1988~. Planned changes in the ESP designed to support the current lease schedule include a change of emphasis from prelease studies to studies of postlease environmental effects, more emphasis on generic studies, and development of a strategy for postlease monitoring (Aurand 1988; U.S. DOI, 1988b). 1ME PRESENT STUDY In 1986, in response to a request from MMS to review the ESP and recommend future directions, the Board on Environmental Studies and Toxicology of the NRC formed the Committee to Review the Outer Continental Shelf Environmental Studies Program. That committee, consisting of experts in ecology, energy production, geochemistry, marine geophysics, oilfield technology, geology, law, physical and biological oceanography, policy, and resource management, is charged to provide an unbiased, independent evaluation of the adequacy and applicability of the studies used to inform leasing decisions and the prediction and management of environmental impacts of OCS oil and gas activities, provide specific recommendations for future ESP studies, identify issues about which there is sufficient information, and provide a state-of-the-art review of the available information relevant to the program. Three panels were established to examine specific subject areas physical oceanography, ecology, and ~ socloeconomlcs. The current report by the Physical Oceanography Panel is the first of three panel reports. It evaluates the physical oceanographic aspects of the ESP and includes recommendations for future directions the program should follow. The main objectives of the evaluation were to provide an unbiased, independent evaluation of the adequacy and applicability of ESP physical oceanography studies; to provide specific recommendations for future ESP physical oceanography studies; and to provide a state-of-the-art overview of available information on each major issue reviewed, based on MMS studies and other relevant data bases and literature. The panel recognizes that the ESP is not intended to be a broad, general science program, but is designed instead to answer questions about the environmental and socioeconomic effects of oil and gas exploration and production. Nonetheless, the answers to those questions must be based on sound science. This chapter describes the ESP and the nature of OCS activities. Chapter 2 identifies physical oceanographic processes and analytical methods that are relevant to understanding the impacts of OCS activities and provides a state-of-the-art review of current knowledge of these topics. Chapter 3 provides descriptions of the four OCS regions and evaluations of the studies done to date, and Chapter 4 provides recommendations for future ESP physical oceanography studies. Appendix A is a glossary of physical oceanographic terms used in this report, Appendix B is a summary of a workshop on numerical modeling initiated by the panel, and Appendix C is a list of physical oceanographic projects funded by the ESP.

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INTRODUCTION PLANNING AND PROCUREMENT OF ENVIRONMENTAL STUDIES Development of a Studies Plan In 1978, a framework was established for setting study priorities, based on their importance for decision making, timeliness, generic applicability of results, availability of information, and applicability to issues of regional or program concern. To develop a list of study topics, MMS identifies issues, primarily through the regional offices and with the help of advisory groups (e.g., the RTWGs or the SC) and interested parties (e.g., environmental groups and industry associations). The ESP staff then translates the issues into questions that reflect information needed for decision making. MMS regional offices, with help from the RTWGs and the SC, evaluate the resulting list of study topics for scientific and technical feasibility, availability of information, scientific merit, and the time during which or by which the information is needed. The list of study topics is also reviewed by other federal agencies and scientists in the academic community, in state and local governments, and in industry. After the review is finished, each regional office submits a draft regional studies plan to the BES in Washington, D.C. The plan includes a statement of regional needs for information, the regional perspective on the priorities of these needs, a list of proposed study topics, and a brief description of the rationale for each proposed study. The BES coordinates the development of a "national studies list" from the proposed study topics and ranks them for funding priority based on criteria that include consideration of how the proposed study fulfills legislative mandates and other legal requirements ant! of whether the study will be completed in time for use in specific leasing decisions. Once approved, the final national studies list serves as the basis for requesting the yearly research appropriation from Congress. Contracts for the studies are then funded by MMS from its appropriated budget according to rank, until funds are exhausted. Since 1982, MMS has been providing support for the review, publication, and dissemination of ESP results, including publication in refereed journals (pers. comm., U.S. DOI, MMS, 1989~. Contractors include private industry, universities, research institutes, or nonprofit organizations. The procurement process normally is competitive and is based on requests for proposals (RFPs) and associated statements of work prepared by MMS. In Alaska, marine environmental studies have been administered in part by the National Oceanic and Atmospheric Administration (NOAA) as part of the OCS Environmental Assessment Program (OCSEAP), under an interagency agreement with MMS that is renewed every 5 years. After the national studies list is approved, NOAA prepares a technical development plan for studies in the Alaska region (U.S. Department of Commerce, 1988~. In June of 198S, the General Accounting Office (GAO) issued a report that concluded that, because of reductions in funding, the duplication of administrative functions between NOAA and MMS had become inefficient and that consolidation of the programs could save up to $1.3 million a year. GAO recommended that MMS develop alternatives to make the program more efficient and, in the selection of alternatives, consider other issues such as staffing, public perception of objectivity, and continuity of scientific expertise in addition to potential dollar savings (U.S. GAO, 1988~. MMS and NOAA have been working to reduce management duplication by attempting to use NOAA staff for scientific investigation rather than as technical managers of contracted studies. In response to the GAO recommendation, MMS is negotiating an agreement by which NOAA will cease to issue contracts by the beginning of FY 1991 and will propose only in-house studies beyond that date. MMS would support an agreed-upon 3-year work plan (U.S. DOI, l98Sa; pers. comm., K. Turgeon, MMS, May 9, 1990~. 17 Implementation of Studies According to Lease-Sale Schedules The planning process for individual studies has been governed primarily by a lease-sale schedule, which is established in a 5-year planning document. The most recent 5-year program plan covers mid-1987 through mid-December 1992. Studies must be initiated well in advance of a lease sale or any other decision they are intended to support if they are to be useful. A

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18 PHYSICAL OCEANOGRAPHY OF THE U.S. OUTER CONTINENTAL SHELF prelease, 15-month study would normally be included in a regional studies plan approximately 34 months before the beginning of the lease-sale process, which begins with the identification of areas having hydrocarbon potential. Table 7 provides an example of how a prelease study is tied to the planning and implementation steps in the ESP and in the OCS leasing process (pers. comm., U.S. DOI, MMS, 1988~. The actual timing varies with the individual studies and lease sales. TABLE 7 Planning and Implementation Steps in the OCS Environmental Studies Program and Lease-Sale Process -34 -30 -27 -20 -17 -12 7 3 o 1 5-9 12 13 14 18 Draft regional study plan (described above) Final regional study plan (described above) National study plan (described above) Procurement plan Draft statement of work Final statement of work Request for proposal Contract Area of hydrocarbon potential identified Call for information: MMS publishes notice of intent to prepare EIS in the Federal Register. Industry invited to indicate areas of interest. Interested parties may comment on topics and areas of concern. No decision yet made about proceeding with sale. Identification of area to be analyzed in EIS, identification of alternatives for EIS, estimation of resources, and preparation of oil spill report for proposed action and for alternatives. Draft report of study results due. Draft EIS and final report of study results describes planning area, analyzes potential environmental effects of oil and gas leasing, and discusses mitigating measures proposed to resolve conflicts. Followed by public comment period. Public Hearing opportunity for oral comments on draft EIS Close of comment period on draft EIS Final EIS assesses comments from the state and the public. Secretarial issue document (SID) prepared that analyzes all issues involved in the proposed sale and possible coastal zone consistency conflicts. The SID, accompanied by the EIS, is sent to the assistant secretary for review and decision on whether to issue a proposed notice of sale. 19 Proposed notice of sale- details terms and conditions of proposed sale, blocks proposed for leasing, stipulations and other mitigating measures to be required, and proposed bidding systems 21 Governors' comments due- used by MMS to develop recommendations to the secretary. SID and final EIS sent to the secretary. The secretary is required to accept the recommendations of a governor if he determines that they provide a reasonable balance between the national interest and the interests of the statets). 22 Final notice of sale- published at least 30 days before sale. Specifies date, time, location, blocks to be offered, and terms and conditions of sale. 23 Sale sealed bids opened and read by regional director 24 Bid review-high bids evaluated to assure receipt of fair-market value. Sale results also reviewed by Justice Department to ensure that awarding leases does not violate antitrust laws. 25 Leases issued- bids accepted or rejected within 90 days of receipt. Leases issued for accepted bids 1 to 2 months after sale. NOTES: In this example, 5 years elapse from the completion of a draft regional studies plan to the lease sale. The postlease process includes (1) exploration plan evaluation and drilling permit approval, (2) development and production plan evaluation and approval, (3) pipeline permit issuance, (4) lease termination or expiration. Source: Pers. comm., U.S. DOI, MMS, 1988.

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INTRODUCTION 19 WHY MMS NEEDS PHYSICAL OCEANOGRAPHIC INFORMATION Physical oceanography provides important inputs for calculating estimates of the transport and fate of oil and related materials in the ocean. These calculations in turn provide the basis for estimating potential impacts of oil on resources; the latter is the primary environmental concern in the management of the ESP. Projection of potential oil-spill impacts is based on results generated by the Oil Spill Risk Analysis (OSRA) model, developed by USGS in 1975. OSRA predictions provide the basis for imposing stipulations or deleting certain tracts from leasing where there is high probability that an oil spill would affect particularly sensitive areas and valuable resources. Because potential risks are principally evaluated through OSRA modeling, the ESP has used physical oceanographic information primarily to support the OSRA mode! and to prepare associated EISs. Because results of ESP studies are used by MMSts Branch of Environmental Modeling (BEM) and by producers of EISs (the four regional offices of the Branch of Environmental Evaluation (BEE) among others), some discussion, conclusions, and recommendations pertain to those entities as well as to the ESP. The interrelationships between BES (the coordinator of the ESP), BEM, and BEE are shown in Figure 4. The OSRA model estimates the probability of oil spills in a specific lease area, calculates oil-spill trajectories from selected launch points, and estimates the probability that an environmental resource or coastline segment will be contacted by releases from the selected launch points. It provides the quantitative basis for calculating the probability of occurrence of an oil spill combined with the probability that a given spill will come into contact with resources. Physical oceanographic support of OSRA modeling has been provided directly through numerical modeling studies of the circulation of each of the major OCS regions the outputs of the circulation models are "data" for OSRA models and indirectly in the form of extensive data bases obtained through large-scale field observation programs. The OSRA model is further described below. . Physical oceanographic information is also used to support biological and ecological studies and to predict the transport of drilling muds and cuttings and discharges of coproduced waters containing petroleum compounds and other byproducts of oil exploration and production. Variability of physical oceanographic characteristics, for example, may be a cause of variation in biological communities and may be useful in interpreting long-term monitoring and cumulative impact studies. Winds, waves, currents, and circulation in general determine the extent of pollutant transport, dispersion of waste products, transport of drilling muds and cuttings, discharges of coproduced waters containing petroleum compounds, and flushing of waste material from an area. ACQUISITION AND USE OF PHYSICAL OCEANOGRAPHIC INFORMATION Physical oceanography studies acquired by MMS tend to be of two separate types: (1) large-scale, multiyear, observational field programs with associated data analysis and interpretation and (2) numerical modeling studies of the circulation of major shelf areas (e.g., the Gulf of Mexico, California Shelf, Atlantic coast, Bering and Chukchi seas, and so on). Rarely are the two study types mixed. The only case found of such integration was in the Santa Barbara Channel circulation study (Gunn et al., 1987), in which the numerical modeling and observational programs were joined into a comprehensive study that included comparing model results with data from field studies. For the observational studies, the primary product is a final report documenting the study results. In addition, at least in recent years, the contractors have been encouraged and in some cases required to publish the results of their investigations in the refereed literature. Data generated during the field studies are also sent to NOAA's National Oceanographic Data Center (NODC) for archiving. The deliverables of the modeling studies generally include a final report, a user's manual for the model, and some form of mode! predictions. For modeling studies on the east, west, and gulf coasts, the principal data deliverables have been predictions of the mean climatological flows over various time scales at spatial resolutions of typically 15 to 30 km. These have been the

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INTRODUCTION principal oceanographic inputs for oil-spill trajectory calculations. Recently, MMS has specified time-dependent velocity fields. Mean climatological flows have been primarily used in forecasting oil-spill trajectories. The principal forcing mechanisms are density and the seasonal mean wind stress. These data sets are then used as input to the OSRA model (Smith et al., 1982) to define the mean flow fields. Incorporation of higher-frequency variations (tides, Ekman transport, slope currents, eddy/ring dynamics) in the flow are either ignored as being unimportant or are parameterized in the OSRA model. The OSRA model uses a Monte Carlo technique to calculate spill trajectories for selected launch points in a proposed lease area by season or month. The model then predicts (1) the probability of oil-spill occurrence using historical data, (2) the "hits" or number of times a spill encounters an environmental resource target (wildlife, fishing area, rookery, spawning area, nesting area, and so on) or shoreline segments, and (3) the probabilities of conditional impact probabilities on the resource within a preselected time. In Alaskan waters, however, the method of predicting oil-spill trajectories for selected launch points and seasons depends on the contractor. The most recent contractor has assembled the hydrodynamic field from a series of superimposed model simulations. The spatially and temporally varying wind field is obtained from a meteorological model. The environmental data sets are typically 10 years in duration. Trajectory calculations are made by assuming random start times within the time period of the environmental data sets. The OSRA model is then used to complete predictions of the probability of oil-spill occurrence, hits on environmental resources and shoreline segments, and conditional impact probabilities, just as for lease areas of the contiguous United States. The contractors for Alaskan studies hence perform simulations for circulation and oil-spill trajectories. In Alaskan waters, simulations for tide, wind, and density-induced forcing are performed. Early contract efforts focused on tides as the principal forcing mechanism. Later studies have taken a more comprehensive view of the circulation. Simulations of oil-spill trajectories have generally followed the same methodology as in the OSRA model; however, the exact formulation has depended on how the contractor chose to describe the circulation field. An additional complication in Alaskan waters is the role of ice and its influence on oil-spill trajectories (ice occurs only occasionally in coastal waters of New England and nowhere else in coastal waters of the contiguous United States). Contractors have used numerical simulations of ice motion satellite or in situ observations, or climatology or some combination of these to define the ice dynamics. Oil-spill-trajectory algorithms are modified to account for the effects of oil-ice interaction. 21 Another important difference between trajectory calculations for the contiguous United States and Alaskan waters has been in the selection and use of meteorological information. For the east, west, and gulf coasts, the wind fields used to drive the circulation model have not generally been-consistent with those used in the OSRA model. Spatially and seasonally varying climatological mean wind and density data are generally used to drive the circulation models whose output provides input for the OSRA model. On the other hand, the OSRA model for the east, west, and gulf coasts until 1989 used a transition-probability matrix approach, normally based on an analysis of winds observed at selected stations over long periods, to describe the wind field. Spatial variability has been addressed by selecting discrete zones over which cIata from a given station and its associated transition-probability matrix are assumed to apply. This may not have produced an accurate representation of the wind field. Since 1989, MMS has used LFM and FNOC (see glossary) "ridded wind products instead of the transition matrix (pers. comm., MMS, 1990). In reviewing the models of oil-spill trajectories anti environmental-resource impacts used by or developed for MMS, it is evident that, despite differences between the approaches in Alaskan waters and the contiguous United States, the general strategy is to rely extensively on the use of model-derived results to estimate the circulation for a given area. The use of circulation data sets based solely on field observations or derived from a melding or assimilation of field observations and model results appears to be minimal at present. On the other hand, the meteorological forcing used in circulation and trajectory modeling for most areas has been based on a synthesis of wind or pressure field observations to obtain a climatological description, a transition-probability matrix, or a weather-pattern typing.

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22 PHYSICAL OCEANOGRAPHY OF THE U.S. OUTER CONTINENTAL SHELF Circulation and trajectory model results are ultimately integrated into the EISs used for lease sales through the prediction of hits on resources and the associated conditional probability that a resource will be hit for a given oil-field exploration and development scenario. However the actual influence of the results of the large-scale physical oceanographic field programs on preparation of impact assessments in EISs is less clear. The information derived from the observational programs is integrates! with the model results to describe the circulation that is ultimately summarized in the EISs, but observations are not adequately used to validate the models on which the impact assessments in the EISs are based. The field information also appears to be used by other investigators (biologists, chemists, and geologists, for example) to assist them in interpreting and analyzing their data. Other obvious uses of the observational data and associated interpretations would be (1) to evaluate and improve circulation mode! predictions and (2) to provide data from which an independent circulation field can be described for input to the OSRA model. However, cases in which detailed model-data comparisons were done are extremely few. As noted above, the use of observational data to define circulation fields or to supplement model results is limited. WHAT INFORMATION IS NEEDED Information Needed for Leasing Decisions To make predictions of trajectories for water parcels and materials, a representation of the current field that is in quantitative agreement with existing observations is needed. Preliminary calculations using robust assumptions and the simplest of models, statistical representations, and representations of the circulation based on observations can provide a useful distillation of the observational data for preliminary assessments and for checking and refining models. The panel believes that a rapid and cost-effective method of improving the representation of the circulation would be based on field observations. The observational information and the representations of circulation should include contributions from motions in the following frequency bands, which are known to be important, or adequate parameterization of the effects of these motions: . the seasonal mean circulation, including known contributions from the local density field, nonlinear tidal current interactions, and the regional circulation; low-frequency currents induced by winds and major current excursions; and tidal currents, including internal tides. The information should include data on the vertical structure in the currents and appropriate vertical mixing rates. The currents associated with other processes, such as fronts and various eddy motions, may need to be included or parameterized, depending on the results of sensitivity studies. A quantitative intercomparison of predicted and observed currents is imperative. Error estimates must be computed for trajectory predictions. The intercomparison must involve the latest data bases of Lagrangian (drifter) and Eulerian (moored measurements) currents and must involve comparisons for particular (frequency-band) flow components. Studies should be conducted on the sensitivity of circulation model results to initial- and boundary-current features, processes, and parameterizations. These studies should be used to identify important factors and to quantify uncertainties in predictions. Particular attention should be given to the sensitivity of Lagrangian trajectories to the model representation of the current field. The development of the above information is a nontrivial task. Communication with the scientific community must be maintained, including ongoing peer review. Results of this research effort, and other information used in the OSRA model, should be clearly referenced in EISs. Full trajectories and impact probabilities must be presented, independent of and in addition to spill probabilities.

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INTRODUCTION Information Needed for Development and Production Decisions Chronic discharges that might have adverse ecological impacts are more likely to occur during the development and production of oil and gas than at earlier stages. Thus, appropriate knowledge pertaining to the inputs, fate, and effects of expected chronic discharges must be integrated before development and production occur. The physical oceanographic component of the required information should consist of robust estimates of fields of exposure-including expected duration-to chemical contaminants for valuable living resources in and near a lease area. In addition, physical oceanographic knowledge must be sufficient to estimate oil-spill trajectories for projected specific sites of production and transport (e.g., platforms, pipelines, and barge and tanker routes) for a lease area. The uncertainties associated with these estimates must be provided. 23 Criteria for Judging Adequacy of Scientific Information The panel's operational definition of "adequacy" for scientific information has two aspects: completeness and scientific quality. Of course, "complete" scientific information in the ultimate sense is neither feasible nor necessary for making decisions. Rather, the panels criteria for completeness are based on whether the coverage of physical oceanographic topics is appropriate for the ESP's mandate. The standards of scientific quality entail repeatability, reliability, and validity of measurements and analyses, including appropriateness of methods and subject. The measure of scientific quality used by the pane! is whether the study methods described represent the current state of good practice in each scientific field (i.e., whether the studies would be likely to pass peer review). This does not imply that the criterion is actual publication in a peer- reviewed scientific journal, but rather that the quality of the data and scientific interpretations used to make OCS decisions should meet this basic scientific standard.

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