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3 PRESENT AND POTENTIAL USES OF THE SEABED The contribution of the ocean sector to the U.S. economy was about 2.6 percent of the total gross national product (GNP) in 1987 (Pontecorvo, 1989), an amount on the same scale as other components of GNP, such as mining, transportation, and communications. The role of the oceans as a resource base for future growth and development is likely to increase under the pressures of population growth and economic expansion (Corell, 1988~. This chapter identifies existing and potential uses of the seabed, assesses their current scope and future potential, estimates time frames required for development, and examines constraints to current and future development. Problems and issues associated with each resource or activity are analyzed, particularly existing or potential conflicts among different uses. Resources and uses examined include oil and gas exploration and development, mineral exploration and development, waste disposal, cables and military uses, biological resources, ocean energy resources, and cultural and recreational resources. The technology and information required to develop these resources or activities are examined in depth in Chapter 4. OIL AND GAS EXPLORATION AND DEVELOPMENT AND OFFSHORE STRUCTURES Background Since the first oil and gas wells were drilled from piers offshore of Summerland, California, in 1896, the U.S. petroleum industry has been shifting a greater percentage of its activities from onshore to offshore. Today, offshore oil and gas production is an important source of the nation's energy supplies. In 1985, 11 percent of total crude production (1.07 million barrels) and 25 percent of total gas production (1,335 billion m3) was produced offshore, and it is estimated that the percentage of U.S. oil and gas reserves from marine sources will continue to increase each year as land reserves decline (Bettenberg, 1987; OTA, 1985; Nehring, 1981; MMS, 1987~. The USGS estimated in 1981 that 26 to 41 percent of the oil and 25 to 30 percent of the natural gas that will be discovered and recovered in U.S. controlled territory in the future will be found offshore within the EEZ. Offshore oil and gas production also began to move toward the Arcti~specifically the Beaufort, Chukchi, and Bering seas when activities in the Beaufort Sea commenced in the mid 1970s. The technology and operational expertise associated with hydrocarbon exploration is well developed for activities conducted from mobile structures, such as jack-up rigs or submersibles; floating vessels, drill ships, or semisubmersibles (Figure 3-1~; and fixed structures for up to 300-m depths, such as template type platforms, tower platforms, or caisson platforms (over 4,100 of these platforms have been successfully installed offshore [Anon, 19~. In addition, design and 20
1 POSTED BARGE ~1 SUBMERSIBLE ~1 LILII~U1 21 JACK-UP RIG SEMI-SUBMERSIBLE DRILLSHIP 1 ~ _ ~ ~1,,. .,,, l 3 m 12 m FIGURE 3-1 Family of offshore exploration drilling rigs ~ 90 m ILl it, 900 m + - DEEP WATER \ construction capabilities for new types of production structures for water deeper than 300 m-guyed towers, tension leg platforms, compliant towers, and subsea production systems (Figure 3-2)-have improved greatly over the last decade (OTA, 1985~. Exxon installed the first guyed tower (Lena) in 300 m of water (LeBlanc, 1983) in 1983 and Conoco's installation of its tension-leg platform Joliet in 535 m of water was scheduled to be completed in August 1989 (Ocean Oil Weekly, 1989~. Three other production systems have also been installed in deep waters: Shell's Cognac (312 m) and Bullwinkle structures (412 m), and Placid's Penrod 72 (465 m) (Ocean Oil Weekly, 1987 and 1988~. Subsea production systems are an important alternative for deepwater field development. Although over 100 of these systems have been installed around the world in a variety of water depths, Placid Oil's subsea system installed in the Gulf of Mexico at a site in 680 m of water is the maximum depth for the U.S. EEZ (Wickizer, 1988~. This system is an attractive cost-saving option for well completions in water depths greater than 1,000 m, since the wells are drilled from a floating rig and completed on the seafloor. The majority of the subsea completions are a single well classified as a "wet" system that relies on a Bowline to transport the hydrocarbon to a nearby fixed or floating platform for processing before transporting the oil and gas to market. The ~dry" system places an atmospheric chamber around the wellhead on the seafloor, allowing Bowline connection and maintenance to be performed by workers inside the chamber. In the future, subsea production systems of the dry type will be used more widely in water depths from 1,000 to 2,000 m, especially for satellite reservoirs. Improvements in deepwater Bowline installation and artificial lift technology should allow the system to be economically attractive for water depths out to 3,000 m. To date, arctic activities have primarily involved exploration wells drilled from artificial islands, although a few wells have been drilled from mobile steel caissons like the one shown in Figure 3-3 (Yokel and Bea, 1986~. Improving the nation's capability to produce oil and gas from the EEZ will continue to depend on improving these technologies in order to move into the frontier areas like the Arctic and deep water (over 300 m).
WATER DEPTH FEET, _ _ 2000 1 500 1000 500 22 GRAVITY FIXED GUYED TENSION-LEG BUOYANT SUBSEA COMPLETION PLATFORM PLATFORM TOWER PLATFORM COMPLIANT TOWER 700 - 2000 FEET 1000 - 3000 FEET 1000 - 2500 FEET (200 - 600 METERS) (300 - 900 METERS) (300 - 750 METERS) 0 - 700 FEET 0 - 1000 FEET METERS (0 - 200 METERS) (0 - 300 METERS) 600 500 / ~ / ~ 400 -300 _~_ it, ~ 0110 ~ ~ L_ FIGURE 3-2 Range of water depths FIGURE 3-3 Mobile steel arctic caisson production platform. 3000- 10000 FEET (900 - 3000 METERS) FLOATING PLATFORM , .. l ll l l l 111 1~1 111 1 11 111 1 11 y ,. -. GUY-LINES \~ TETHERS SEABED ANCHOR r Pl.Es for various types of production platforms. s_ lo, - ~ ~, ;,; t; . . . Scope of Development Future offshore oil and gas activities will include development of presently unleased areas of the outer continental shelf (OCS) where mature technology offers assurance of operationally safe, environmentally sound, and economically secure development (NRC, 1979 and 1977~. Although oil and gas reserves in frontier areas of the EEZ cannot be forecast with absolute certainty, since 1975 the number and extent of exploration and recovery activities in water depths greater than 300 m has
23 increased dramatically. For example, the number of deepwater wells drilled in the Gulf of Mexico increased fourfold since 1975 (Figure 3-4), and in 1988 Shell Oil set a new world depth record when it spudded a well in 2,273 m of water in the Mississippi Canyon area. Most of the production of oil and gas has occurred to date in the shallow water of the Gulf of Mexico and offshore California. Some studies (OTA, 1985) suggest that most of the undiscovered oil and gas in the United States will exist offshore Alaska and California and in the deep water of the Gulf of Mexico. Trends suggest that actual production (including subsea completions) in water depths up to 2,000 m is likely by the end of this century. As EEZ oil and gas development expands farther in these deeper waters, construction and operating costs will increase due to the logistical requirements of operating farther from land. As a result, production configurations are likely to change to more-wells per platform, more processing facilities, and fewer but larger platforms. As the capital investment and population per platform increases, the knowledge requirements for platform design and the operational environment will become even more exacting. To ensure that sound engineering design principles and practices are followed, industry groups, such as the American Petroleum Institute, will need to update their guidelines of recommended practices (API, 1987~. Uncertainties are inherent in predicting overall potential value to the nation of EEZ oil and gas resources. Uncertainty exists concerning the possible size, quality, and production costs of reservoirs that may exist, especially in the Arctic and deepwater areas of the continental slope. Ongoing development of an expanded and improved capability for resource forecasting in the entire EEZ is extremely important (USGS, 1986~. The ramifications of this issue will require joint government and industry consideration of policies influencing developmental planning and economic strategy. In addition to the size and quality of oil and gas reserves that may be located in deepwater and arctic environments, economic factors and technical constraints will affect future development of EEZ reserves. Among the important economic factors are world oil prices, availability of oil from dependable sources, and production costs. The primary technical constraints facing designers will be depth limits of current platform and pipeline technology; lack of knowledge about new seafloor sediment types; and lack of understanding of geological, biological, and oceanographic processes that control seafloor conditions that impact platform and pipeline design and operation. Development Constraints Many technical and economic constraints face the offshore oil and gas industry as it moves farther onto the continental slope and into unexplored arctic regions. The environmental hazards of operating in deep and ice-infested waters are considerably greater, and overcoming them will be far YEAR ~ 975 1 976 1 977 1 978 1 979 1 980 1 981 1982 1983 1984 FIGURE 3-4 Number of ~ 985 deepwater exploration ,9~86 wells in the Gulf of 1988 Mexico in water deeper than 180 m. Z" A (SHELL'S COGNAC PLATFORM INSTALLED) , ~ (EXXON'S LENA PLATFORM INSTALLED) ~'''~,,,~ i ,,,,,,,,,,,, ,,~,,~,,,,~, .,~,'',,, ,~ 0 10 20 30 40 50 60 NUMBER OF EXPLORATION WELLS WATER DEPTH OF WELLS 180 TO300 m > 300 m
24 more costly than previously experienced and will require innovative approaches to the design of drilling operations and structures (Wickizer, 1988~. Despite these challenges, development of EEZ oil and gas resources is proceeding and can be enhanced by long-term planning and regulatory requirements that reflect sound understanding of the seabed environment. The sections that follow describe the information needed to improve the state of knowledge of this environment that will lead to such understanding. Seafloor Gradients Site-specific studies already completed for the oil and gas industry on the continental slope indicate that seafloor bathymetry, slopes, and local relief are considerably more complex than on the shelf. lithe severity and diversity of bottom relief may be important factors in development decisions, because areas with steep bottom slopes and rugged terrain may be too difficult to operate in and therefore uneconomical to develop. By comparison, bottom conditions on the shelf have never proven severe enough to be intractable to engineering solutions to detect and avoid problems. A related problem is that existing bathymetric maps for EEZ continental slopes are not accurate enough to develop site-specific oil production systems. Considerably more detailed information on water depths and gradients is needed for potential development sites. It should be noted that multibeam swath bathymetry does not address the accuracy levels necessary for site-specific development. Sea Beam, for example, covers a swath of 0.8 times the water depth with a resolution of 5 percent of water depth. In 4,000 m of water, a swath width of more than 3 km results in a spatial resolution of about 200 m (Tyce and P'yor, 1988~. Seafloor Geologic Processes Seafloor or near-seafloor processes-such as landslides, turbidity currents, erosion/scouring, faulting, creep diapirism, gas seeps, and sediment collapse-can impose considerable constraints on the development of engineered structures, depending on their magnitude and frequency. Many of these processes are present and active on the continental slope: for example, active faults, diapiric uplift, recent landslides, and subsidence all occur on the Gulf of Mexico slope (see Figure 2-4) (Campbell et al., 1986~. Arctic frontier regions pose many different geologic hazards to development, including ice scour, freezing and thawing cycles of ice-bonded sediments, and gas hydrate stability (NRC, 1986~. - An important constraint to EEZ development in deepwater and polar regions is the lack of knowledge and understanding of distribution and intensities of these processes. Moreover, they cannot be predicted from available regional geologic information. For example, a submarine landslide large enough to damage production facilities may be too small to show up in regional geologic data. Furthermore, even if a landslide is discerned, the data may not be sufficient to pinpoint its origin, so it wouldn't be useful in predicting future events. Thus, it is essential that regional data be interpreted in a wav that Drovides a useful context for Planning subsequent detailed. ~ ~ ~ ~ 1 ~ A .. · ~- . · . . . . . . _ _ _ . . _ _ slte-specl~lc geophysical surveys, which are always required to evaluate the area s potential for exploration and production. Because of the complexity of deepwater and arctic frontier regions and associated higher operation costs, it is especially prudent to evaluate potential production constraints before beginning exploratory drilling. Knowledge If data from site-specific geophysical studies are combined with geotechnical information, it is possible to quantitatively predict the possible effects of seabed processes on seafloor installations
25 over their lifetimes (Figure 3-5~. However, such an integrated approach goes beyond routine geological surveying and measurement of geotechnical properties (Campbell et al., 1988~. Engineering Properties of Sediments Knowledge of sediment properties, such as static and dynamic stress and strain behavior or compressibility and consolidation characteristics, is fundamental when evaluating geologic processes and designing piles, conductors, well heads, templates, anchors, and pipelines. A variety of techniques are used for offshore site investigations, such as laboratory testing of recovered samples combined with in situ measurements, which are now successfully used to depths of up to 1,000 m (McClelland and Ehlers, 1986~. (More detailed discussion of engineering properties and problems of acquiring reliable data are presented in Chapters 2 and 4.) Several important geotechnical problems arise when developing oil and gas production facilities for deep water and the Arctic. First, unique or exotic sediment types with fundamentally different properties and physical behavior are being encountered on the continental slope. For example, gas hydrates have been found in surface sediments in water as shallow as 450 m in the Gulf of Mexico and even in shallower water in the Arctic (Brooks et al., 1986~. They are interspersed within the sediment matrix as small, contained ice pockets, or may have the form of large, conical shaped, ice- infested mounds that extend laterally hundreds of meters. The hydrates may pose design problems for foundations if they are heated by adjacent production well conductors and thereby become mobilized (Hooper and Young, 1989~. Similarly, landslides and seafloor eruptions may be related to INTEGRATED STUDIES GEOLOGY ) Geophysics Field Data Interpretation and Maps Site Geology I - Lab Tests 1 ~ Interpretation Hazards and Risks ~ ~1 (~INEERIN: struct(lre an(' Site Location Concepts .. -'is Stress History / ~DeS\ Engineering Geology Model Borings Wild In Silu Tests Lab Tests Foun(~tio Allalysis - Follntlation Design Parameters FIGURE 3-5 Interactive evaluation process for integrating geological and geotechnical information. SOURCE: Campbell et al., 1988.
26 expansion, contraction, or degeneration of hydrate materials (McIver, 1982; Prior et al., 1989~. EEZ development will therefore require determining occurrence, stability, and likely future behavior of gas hydrates. Additional information, such as seafloor temperatures, will be required as a basic input for analysis of heat transfer from wells or pipelines in areas where gas hydrates occur. In addition to gas hydrates, sediments are encountered in deepwater areas that exhibit the relatively high sensitivities (i.e., significantly reduced strength when disturbed) normally associated with bioturbation and high organic content. Such physical behavior can constrain foundation design because of the potential for slope failure, or loss of shear strength affecting foundation installations (Hooper and Dunlap, 1989~. Improving knowledge about this type of sediment and determining related engineering constraints are important problems to resolve. Gases in deepwater sediments are a greater concern than shelf sediment gases because the hydrostatic pressure is greater and there is a greater likelihood that gas expansion due to heating from oil and gas production will affect foundation sediments. All the various gas phases~issolved, vapor, or solid-are detrimental and can adversely influence foundation conditions (Esrig and Kirby, 1977; Whelan et al., 1977~. A separate yet related set of geotechnical problems is the lack of technology available for sampling and testing deepwater areas (discussed in detail in Chapter 4~. Cost-effective systems for geotechnical sampling and testing are presently-not available for deployment from remotely operated vehicles (ROVs) or tethered-type seafloor platforms (Young et al., 1988~. Production Siting and Facilities Considerable progress has been made in using geological and geotechnical data to conduct integrated risk analysis for the design of platforms and pipelines on the continental shelf. For example, in the Mississippi delta mudslide area, wave and sea bottom interaction models have been used successfully to determine foundation loading due to mudflows (Kraft and Ploessel, 1986~. Deepwater areas of the EEZ will require correspondingly appropriate geological and geotechnical models for these and other complex processes. For example, diapiric or gas-induced slope failures are understood only qualitatively, and sediment and foundation interactions under earthquake loading-including stress propagation and modification of sediment properties-are poorly understood. Quantitative data for a wide range of deepwater sites that can be used to formulate analytical models and calibrate them to specific design conditions will be required for development of these areas to proceed (American Society of Civil Engineers, 1983~. There is considerable debate over the advantages and disadvantages of various deepwater structural systems, such as compliant towers, tension leg platforms, or subsea production systems (Figure 3-2~. Design and emplacement of these new types of structures require site-specific geotechnical data and engineering and verification criteria that are presently based on single prototype designs. Hence, new innovative structures will require environmental data obtained by monitoring full-scale installations to assess the performance of foundation elements, including piles, mats, and anchors. Seabed pipelines that transport oil and gas from offshore production platforms to refining or storage facilities are an important component of offshore development. At the end of 1985, there were 12,500 km of pipeline in the U.S. EEZ (NRC, 1985~. Oil spills resulting from ruptures of these pipelines are a major concern because they can cause extensive local environmental damage. But, historically, pipeline ruptures have released far less petroleum into the marine environment than other transport systems, such as coastal tankers and barges (NRC, 1985~. Any natural phenomenon that presents a potential hazard to a pipeline must be considered, however, and protective measures taken. Burial in the ocean bottom is the most effective way to protect them, but in some areas, such as potential sites of large mass wasting, the only solution may be to keep pipelines out of the region altogether. Deepwater and arctic areas pose new engineering challenges to pipeline routing, installation, monitoring, and repair similar to those associated with drilling and
27 production. Problems that are unique to pipelines include design for an ice-gouged seafloor, and leak detection and repair in ice-covered areas. Summary Over the last 40 years, offshore oil and gas technology has evolved that allowed the design and construction of facilities and equipment capable of extracting oil and gas from the continental shelf in a safe and pollution-free manner. If the industry is to move beyond its present capability to new areas of the EEZ, the difficulties of operating in more demanding and hostile environments must be solved. Developing equipment and platforms that can meet the challenge of these areas will be costlier, riskier, and more time consuming than previous offshore efforts, and will be affected not only by technical progress but also by nontechnical factors, such as fluctuating world oil prices, the impact of unstable political regimes in oil-producing countries, and a domestic regulatory climate subject to conflicting public pressures. Equally significant will be the extent to which government and industry cooperate to achieve a proper balance between meeting the nation's energy needs and environmental concerns and maintaining a competitive and technically innovative domestic oil and gas industry. MINERAL EXPLORATION AND DEVELOPMENT Background During the late 1960s to mid 1970s, interest in seabed minerals was stimulated by exploration of extensive deposits of manganese nodules on the deep Pacific seabed. Amid this enthusiasm, recovery and processing prototype systems were developed and claims were staked in the deep ocean. This success also resulted in exploration for other potentially valuable marine mineral deposits in shallow water. By the late 1970s, however, falling minerals prices, combined with U.S. disagreement with Law of the Sea provisions over ocean mineral rights, caused the fledgling marine mining industry to shelve deep ocean mining exploration and systems development at a point where proof of concept and site reconnaissance were accomplished. In 1983, interest in offshore minerals was again stimulated by the EEZ proclamation, combined with the Reagan administration's expressed concern over dependence on foreign sources for strategic minerals. The impact of the EEZ proclamation was to reaffirm and clarify the jurisdiction of the Outer Continental Shelf Lands Act (OCSLA) of 1953, which established regulations for developing mineral resources on the outer continental shelf, and expand it to include U.S. territories as well. EEZ marine minerals are conventionally classified into five groups-aggregate materials, placers, phosphorites, metalliferous oxides, and metalliferous sulfides. Occurrences of sulfur and miscellaneous mineral lodes, such as lead and zinc, are known to exist in the EEZ arid comprise a sixth category in this report. These marine minerals are widely varied both with regard to type and location. Occurrences of marine minerals are widespread throughout the EEZ, with aggregates and placers off both coasts of the United States in mostly shallow waters. Sulfur, also a shallow-water mineral, is found in the Gulf of Mexico. Further offshore and in generally deeper waters off the southeast coast, phosphorites and manganese nodules have been discovered. In the deeper oceans, manganese crustal deposits are located on the slopes of Pacific seamounts and islands, and polymetallic sulfides are located at Pacific Ocean thermal vents or spreading centers. Principal characteristics and geographic locations of known EEZ mineral deposits discussed below are summarized in Table 3-1; additional information regarding extent, content, and location is given in DO! (1987), OTA (1987), and Broadus (1987~. 1. Aggregates, siliceous sand and gravel and carbonate sands widely used for construction, beach replenishment, and concrete and ceramics manufacture, are widespread on the U.S.
- ~ ~ e 7- e e E ~E ~j E D ~: E o ~ E o _ _ ~C C o o ._ ._ ~C ~C _ ~_ C.} c ~eo L: C ~C C °uC 8 .E ~8 .E ~ ~,~ ~ . V: - ._ c) a o - ._ C) - Ct :t ._ ._ ~=C C.) ~ E ~ ._ _ ._ C , cr . fL) E ~ ·- C>. ~ c C) - e~ - c ~ o c E oo~ Co G ~S .C ~ C ~ .~= 3 -` .O a~ ~ o 8 ~ o_ - .- a ~ m C Y o 8 ~ E _ E o ~, o C _ ~D C o e ~_~ 't, oE_ E -2 _ y- o ~ ~U o E ._ ~. _ ~ ~C ~ D U. ~n O c E 8 ~ - o o C ~ ~ ~ ~ ~ ~ - ~q o - - c c ~ ~.D ~ ;= ~ ~ ~ ~ ~ ~ ~ ~ e o" ~ - ~ ~ tee .o c~,,, .c>- e 3 c~ ~e~ et ~ ~ ~ ~ < ~6~ t_ ~ _ _ ~e c ~O |_ O et ~ O c~ ~q Oe ~ s ~ ~ E ._ E . _ _ ~ .-c C C . C C ~ ~o ~e E o ~ ~ ~o ~, ~ ~ ~ .c .t c ~a: ~ c~ ._ e ~_ .Y ~E ~ y c ._ ~ .E o 5 Y 8 ~ ~ E'~ = E ~ E E ~ E e ~ u, ~ C ~ o 8.= i, c 8 ~o o ~ 5. E ~ ~ _ ~ ~ D e o o o e - o ._ 5 .~3 ~C 2 c.- _ ~ c ~ ~ ~ O ~ - ou f2 ~ ~0 °es c .- ~ CL.c _ E E o E E o8` 8 ~o ~o ~_ e c ~; :' c~ O 8 ._ ~ E o O O ~C1 ~ ~ O ~Z ~ 2 C ~ ~ _
29 continental margins. Mining of these deposits, while dependent on local transport economics and market conditions, is presently done in shallow, nearshore waters and provides an alternative to onshore reserves (Katz, 1987~. 2. Placers, heavy sands aggregated by oceanic hydraulic sorting, are the subject of accelerated mapping and exploration because they contain strategic and precious minerals and industrially useful refractor materials and abrasives, and because they are readily recoverable using available technology. Of special interest are the titanium group minerals on the Atlantic and Pacific shelves, chromite sands off Oregon, and gold and platinum on the Bering shelf. Gold placers have been mined nearshore and on beaches in Alaska, Oregon, and California since the early 1900s, and potentially valuable deposits exist farther offshore. 3. Phosphontes have been mapped from North Carolina to Florida out to the Blake Plateau. They contain trace quantities of platinum, uranium/thorium, and cadmium. Onshore phosphate deposits and low-cost overseas resources are adequate to meet near-term needs, but projected closings of Florida phosphate mines (due to soaring land values and environmental concerns) may eventually make EEZ phosphate mining economically viable. 4. Metalliferous oxides (ferromanganese deposits) consist of manganese nodules and crusts that contain strategic and industrially valuable metals, including copper, cobalt, nickel, manganese, and platinum group metals. The nodules occur mostly in the deep ocean outside the EEZ and to a lesser extent on the Blake Plateau. Manganese crust deposits are more abundant in the EEZ and are found on the flanks of Pacific seamounts and islands. 5. Metalliferous sulfides (also referred to as polymetallic sulfides) deposits contain zinc, copper, lead, gold, silver, trace amounts of barium and other metals, and large quantities of iron, which adds little to the deposits' economic value. Polymetallic sulfides are found along active spreading centers, such as the Gorda Ridge off Oregon. 6. Sulfur and miscellaneous minerals are found in shallow territorial waters along the continental shelf. Sulfur deposits are mined from nearshore caprock salt domes in the Gulf of Mexico, and a 1988 lease sale in the Gulf presages extension of sulfur mining into federal waters. In addition, barite was mined for ten years off southeast Alaska, and a lead-zinc-silver lode in the Gulf of Maine was mined in the early 1970s. Both operations successfully used conventional shallow-water dredging barges. Other shallow-water lodes with a greater diversity of metals are likely to be present in EEZ waters off Alaska and New England, and may eventually become commercially viable resources. Commercial offshore mining is not a new phenomenon. It has been conducted since the mid 1800s, but these operations have been nearshore and in relatively shallow waters. The standard marine mining system has been the dredge, which has proven adequate for unconsolidated or weakly consolidated ore bodies in water depths to 60 m and in relatively calm seas. Major advances in methods and mining systems will be required to recover much of the EEZ deepwater deposits previously described. The present state of commercial recovery technology and needed advancements are described in OTA (1987) and Cruickshank (1987~. Scope of Development Minerals markets are volatile, yielding to worldwide demand and socio-political forces. The U.S. minerals industry, squeezed by low international commodities prices and high domestic production costs, experienced a major recession from 1977 to 1987. Low demand and depressed prices continue to plague the industry, contributing to a worsening trade imbalance, poor international competitive position, and declining U.S. minerals production and industry employment (DOI, 1987~. Except for isolated exploitation of shallow-water minerals, nearshore sand and gravel, and placers, this economic climate discourages offshore exploration or mining activities. Although it is presently cheaper to import most hard minerals from abroad, U.S. market conditions are subject to fluctuations caused by such factors as unstable political regimes in Third
30 World countries, changing trade policies among U.S. economic allies, or increased labor and production costs in producing countries. The United States is nearing total dependence on foreign sources for some metals essential to national defense and industrial needs~.g., cobalt, chromium, manganese, and the platinum group metals (Table 3-2~. The need for secure supplies of these minerals, along with decreasing availability of economically mineable onshore deposits, provides an im fetus to identity and quantify domestic mineral resources within the EEZ. This will require improved seabed mapping and exploration technologies, better quantification of extent of deposits, , and continued advancements In offshore mineral recovery capabllltles. An assessment of EEZ mineral deposits that have potential for eventual economic recovery was made by a selected group of experts from government, academia, and industry at a workshop of this committee. Time frames estimated in Table 3-3 represent the group's collective opinion on probable time frames when normally evolving economic conditions may warrant initial commercial recovery. Each deposit was also evaluated for potential for accelerated development in the event that external influences create an improved economic climate or urgent national need. One factor in predicting long-term development time frames for EEZ mining is that the U.S. marine mining industry is not competitive with nations such as Japan, France, the United Kingdom, and West Germany. The United States lags behind these countries in the ability to mine and market presently recoverable marine reserves and resources because of their lower labor rates, fewer regulatory and environmental constraints, and access to government assistance (e.g., joint industry- government development and exploration programs) (DOI, 1987~. In fact, the lack of TABLE 3-2 U.S. Net Import Reliance On Selected Nonenergy Minerals MINERAL PERCENTAGE IMPORTED MAJOR SOURCES (1981-1984) COLUMBIUM MANGANESE MICA (SHEEN STRONTIUM BAUXITE & ALUMINA COBALT PLATINUM GROUP TANTALUM POTASH CHROMIUM no ASBESTOS BARITE ZINC NICKEL TUNGSTEN SILVER MERCURY CADMIUM SELENIUM GYPSUM GOLD COPPER SILICON IRON ORE IRON & STEEL ALUMINUM NITROGEN SULPHU R SOURCE: DOI, 1987. :::::~:: -::: :::::::::: ::: :::::::::: ::::::::::::::::::: ::: :::::: ::::: , , ,... . ,.,,,, ., . . .. .. . '. ... ..1 m. .. I:= .::: :::.: :,:.:::: :: ::::: :::::: :::::::::::::: :::: ::: ::::: ::::::: .1~: :: - G _ ILL ... : ......... . . 3 .,...:,,, ""':':'':,':'22: :2:::,:2:' ,:': ."":"' 2':2 '"2 ' 2:::':2 : 2: 1 ILL ,, ,.,.,-.- ... :: :::::::::::::::::::.:::::::.: :.:: .:.:...:.: :.: :::::::::::::::: ::: :::.:::::: .:.:::: _ - . . . .. .... : : :.:: :. =,:] . :.: :.::.:::.::::::::.::::::::::,:,:.::::.,: ..: : :::: .: :: : 7t 3 - :: :::: ::::: :: . . :: .::::::: 3 ....................................... 6 1 it= ................ ,,,, .! BRAZIL, CANADA, lldAILAND REPUBLIC OF SOUTH AFRICA, FRANCE, BRAZIL, GABON INDIA, BELGIUM, FRANCE, MADAGASCAR MEXICO, SPAIN AUSTRALIA, JAMAICA, GUINEA, SURINAME WRE, ZAMBIA, CANADA, NORWAY REPUBLIC OF SOUTH AFRICA, UK, U.S.S.R. THAILAND, BRAZIL, MALAYSIA, AUSTRALIA CANADA, ISRAEL REPUBLIC OF SO. AFRICA, ZIMBABWE, YUGO., TURKEY THAILAND, MALAYSIA, BOLIVIA, INDONESIA CANADA, REPUBLIC Of GUM AfRICA CHINA, MOROCCO, CHILE, PERU CANADA, PERU, MEXICO, AUSTRALIA CANADA, AUSTRALIA, BOTSWANA, NORWAY CANADA, CHINA, BOLIVIA, PORTUGAL CANADA, MEXICO, PERU, UK. SPAIN, ALGERIA, JAPAN, TURKEY CANADA, AUSTRALIA, PERU, MEXICO CANADA, UK., JAPAN, BELGIUM-LOX. CANADA, MEXICO, SPAIN CANADA, URUGUAY, SWITZERLAND CHILE, CANADA, PERU, MEXICO BRAZIL, CANADA, NORWAY, VENEZUELA CANADA, VENEZUELA, LIBERIA, BRAZIL EURO. ECON. COMM., JAPAN, CANADA CANADA, JAPAN, GHANA, VENEZUELA U.S.S.R., CANADA, TRINIDAD ~ TOBAGO, MEXICO CANADA, MEXICO
31 competitiveness in the international minerals market plagues the U.S. mining industry in general, and will continue to hinder EEZ development and may extend the EEZ development time frames predicted in Table 3-3. If there is a perceived national need within the 10- to 15 year time frame for critical minerals available from the seabed, it may be necessary for the federal government to intercede and assist the mining industry (e.g.,- protection measures and cooperative research and development programs). Development Constraints Information and technology needs for various phases of marine mineral development are summarized in Table 3-4, and the key constraints related to the needs listed in the table are briefly discussed in the sections that follow. Resource Estimation Regional research and mapping provide the foundation for investigating potential mineral deposits and gathering data to formulate geological models of deposit genesis, a key step toward prospecting and exploration. Appropriate models minimize random searching for minerals, and geostatistical techniques building on those models can be useful in estimating tonnage and grade. Continued and accelerated development of these techniques and tools is important to developing deepwater EEZ deposits. Estimating techniques are needed for various offshore deposit types and geologic settings to estimate grade and tonnage of recoverable but unproven deposits. Geological models for ore genesis also need to be developed for various EEZ ore bodies since present knowledge of how mineral deposits form is derived largely from the study of onshore deposits. TABLE 3-3 Predicted Time Frames For Economic Recovery Deposit type Earliest market- Potential for favorable development acceleration Sand and gravel 1-3 years Medium/high Primarily near large urban areas Placers 2-5 years Medium For strategic and precious minerals Phosphorites 5-15 years I~ow Manganese 10-15 years Low Resource assessments nodules and technologies are in place. Manganese crusts 15-30 years Low Polymetallic Undefined Low sulfides Sulfur 1-2 yearsa Low Miscellaneous 2-5 years Low In isolated cases lode deposits where favorable economics occur aSulfur lease sales planned for 1989 demonstrate a near-term market for this commodity.
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33 Reconnaissance and Exploration Locating and characterizing ore bodies are fundamental to developing a mining strategy. Geological ore genesis models and large-area reconnaissance mapping are helpful in defining tlie regional context of potential ore deposits and guide exploration efforts, but this must be followed by site-specific mapping and in situ sampling to evaluate and verify the deposit's economic value. Site- specific mapping is done with towed high-resolution sensors, including side-looking sonar and bottom and subbottom profilers. Improved multisensor, high-resolution survey systems are required to advance the efficiency and accuracy of such ore assessments, especially in deep water. The use of remotely operated vehicles (ROVs) and autonomously operated vehicles (AOVs), as sensor platforms will also improve the effectiveness of site-specific ore assessments (see Chapter 4~. Nonacoustic remote sensing technologies successfully used on land~uch as induced polarization, bulk resistivity, electromagnetism, gravity, chemical, and temperature~ould be useful underwater, but have not yet been adapted to this environment due to development costs and the limited market in the marine mining industry (Francis, 1987~. Electromagnetic techniques, for example, are useful in defining land locations and deposit thickness of heavy mineral placers (due to their magnetic content), but their offshore application is only in its infancy. Optical techniques, including photographic and television imagery of the seafloor, are limited due to turbidity and low or nonexistent light levels in deep water. Improved optics, optical imaging techniques, and more sensitive films are needed. In addition, laser-induced fluorescence or mineral identification through optical spectrometry has not been explored due to technology development costs. Present methods of shipboard resource assessment by drilling and coring are very costly. Development of riserless and seafloor drilling systems tethered to the ship by umbilicals could provide more economic systems to support deepwater EEZ ore body assessment (OTA, 1987~. Recovery Technology A new class of deepwater mining systems will be required to recover deepwater EEZ minerals in commercial quantities. Extraction of EEZ seabed minerals will require advanced mining technologies and systems, especially platforms capable of prolonged operations in virtually all weather conditions equipped with motion-compensated handling and possible onboard beneficiation systems. Future mining systems also will need to be capable of reemplacement offloading of tailings and spoils. These requirements may be met by using large, stable, semisubmersible platforms similar to those developed for the offshore oil industry (OTA, 1987~. It may not be desirable to process all minerals at an offshore mining site, but some beneficiation may be necessary to reduce transportation costs and onshore disposal problems. In the case of precious metals (gold, silver, and platinum) and diamonds, complete onboard processing is proven, practical, and cost effective (OTA, 1987~. Deepwater technologies for fracturing and ripping consolidated deposits will be required along with pneumatic and hydraulic lift systems to transport minerals to the surface. In some cases, preprocessing of bulk materials at the seabed will be needed to concentrate minerals before they are lifted to the surface. Numerous other specific engineering and technology problems will have to be solved by the mining industry to achieve commercial EEZ mining. It is generally conceded that a minumum lead time of 5 to 15 years is necessary to develop fully operational systems. Even though impressive advances were made in developing prototype mining equipment during the 1960s and 1970s to recover deep ocean manganese nodules, present market conditions, the limited financial strength of the U.S. offshore mining industry and its poor competitive position internationally suggest that it will be many years before the U.S. marine mining industry will start to develop advanced commercial mining systems. A concern is that mining of the U.S. EEZ may be
34 done by foreign offshore industries that are more robust necessary development costs and risks. Environmental Impact Assessment , aggressive, and able to undertake the For most of the EEZ deposits considered in this report, the existing background information is inadequate to support suitable environmental impact assessments due to lack of marine mining experience and inadequate environmental data bases for the specific ore bodies of interest. Impact predictions for marine mining are further complicated by uncertain operating conditions and production levels estimated from poorly defined deposit sites. On the other hand, believable and accurate impact predictions are required during prospecting and leasing before commercial mining operations will be allowed to begin. This situation presents industry with a Catch 22" in which early economic assessments must account for unforeseen environmental costs, yet under present regulations must be included in their upfront bonus bidding strategies. For most EEZ mineral deposits, this presents industry with an unacceptably high development risk (see discussion on leasing policy and regulation below). Further discussion of environmental impact assessment and monitoring is presented in Chapter 4. Leasing Policy and Regulation The present U.S. marine hard minerals regulatory situation is at best controversial and at worst inadequate to encourage development of EEZ mineral resources and deposits. The federal policy, administered by the Department of the Interior (DOI) through the Minerals Management Service (MMS), is based on the OCSLA as amended in 1978. Authority for hard minerals mining is derived from Section 8(k), which addresses mineral resources in the OCS "except for oil, gas and sulfurs To fill the regulatory void and encourage development of OCS mineral resources, MMS has promulgated rules, based on the OCSLA, establishing a three-phased regulatory regime for marine minerals development-prospecting (MMS, 1987), leasing (MMS, 1988a), and operating (MMS, 1988b). Although these proposed regulations have a clearly derived authority, many segments of industry and government argue that the OCSLA has serious shortcomings as a legislative basis for hard minerals regulations. From this view, the OCSLA does not treat the EEZ equally with the OCS in terms of its jurisdictional province, i.e., U.S. territories are not part of the OCS but are within the 200-mile EEZ. Of greater concern to the mining industry is that the OCSLA, while adequate and proven for oil and gas operations, does not allow sufficient flexibility for hard minerals leasing and mining. The main issues include the mandatory up-front bonus bidding system, lack of preference rights for companies conducting early prospecting and exploration, the need for a more equitable federal, state, and local revenue sharing and consultation process, and more flexible environmental provisions (U.S. Congress, 1989~. Recommended remedies to the existing regulatory situation range from no action (Pendley, 1989) to various OCSLA amendments (OTA, 1987) to new legislation (Curtis, 1989~. This report takes no position other than to note that the issue has been recognized and recommendations have been made for some years without resolution (NRC, 1975), and the continued lack of a predictable regulatory framework impedes exploration and development of some EEZ resources that have near- term potential for development. In all fairness, the economic situation is a larger deterrent to progress than the lack of policy. However, industry activity in the EEZ will be negligible until the regulatory problems are resolved. Alternative legislation was proposed but not passed in the 100th Congress (H.R. 1260~. During the 101st Congress, a bill establishing a program for the exploration and commercial recovery of hard mineral resources from the U.S. seabed has been introduced in the U.S. House of
35 Representatives out of the Committee on Merchant Marine and Fisheries (H.R. 2424~. The House Committee on Interior and Insular Affairs, Subcommittee on Mining and Natural Resources, may also consider legislation authorizing a self-initiated access system for the rights to explore and develop offshore hard minerals (Brad Laubach, MMS, personal communication). It is hoped that with the emergence of regulations and the ongoing Congressional oversight hearings, a comprehensive and predictable legislative and regulatory framework will emerge to support timely and effective development of EEZ minerals. Use Conficts EEZ mining will inevitably conflict with other potential seafloor uses, such as commmercial pipeline and cable routes, marine traffic lanes, milita~y/defense activities, oil and gas activities, and fishing. Most conflicts can be anticipated and resolved by regulation and negotiation during the long lead times required for exploration, leasing, and development. However, conflicts with fishing and military interests have already caused some concern and may require particular attention by decision makers. If mineral development activity expands in the future, methods for arbitrating conflicts will be required. Discussion of use conflicts is presented in Chapter 6. Summary Although extensive hard mineral resources exist in the EEZ, their extent, value, and commercial recoverability is not well known or adequately quantified. Present offshore mining activity is limited to shallow-water resources, such as sand and gravel, heavy mineral placers, and sulfur. The time and investment required to develop a competitive, economically viable EEZ mining industry especially for consolidated sediment or hard rock minerals~re beyond the present capability of a domestic industry weakened by ten years of a depressed worldwide minerals market and technologically outpaced by foreign competitors operating with the support of their governments. As a result, most companies involved in offshore mining operations and development have reduced their activities or closed, and experienced marine mining personnel have retired or left the industry (DOI, 1987~. The technologies and capital investment required to map and evaluate many EEZ minerals (especially in deep water) are beyond the industry's present capabilities. Thus, present reconnaissance and assessment efforts are primarily federally sponsored efforts. Basic engineering development of new recovery, at-sea beneficiation, and processing technologies presently rests with industry. The present slow pace of deepwater EEZ mineral exploration and development is unlikely to accelerate without improved market conditions and revisions in policy and programmatic incentives in federal leasing programs. WASTE DISPOSAL Background The seafloor and coastal ocean waters surrounding the United States have been used for disposing of dredged material and municipal and industrial wastes for many years. Two arguments have been used for ocean waste disposal. One is that some areas of the marine environment have a lower value relative to alternative onshore sites. The other is that natural cycles in the marine environment can assimilate certain types of wastes without detrimental effects. In the first instance, the decision is to sacrifice a portion of the marine environment (for example, a specific dumpsite) for waste disposal based on the assumption that ocean disposal is more cost effective than other alternatives and that impacts will be confined to the disposal site. The second approach evaluates
36 quantities and types of wastes for marine disposal based on their compatibility with marine biological and geochemical processes. Both approaches are the basis for past and present ocean waste disposal practices. Disposal schemes tend to follow two strategies: dispersing waste in order to dilute it to concentrations low enough to be considered harmless, Or depositing it within confined areas of the seabed or in containers to isolate it from the surrounding environment. Dispersed wastes-generally dumped directly from a vessel at sea-are transported by currents, ingested and excreted by organisms, and incorporated into particles that settle through the water column before eventually becoming incorporated into seabed sediments. Wastes discharged from pipelines tend to result in more localized accumulation of contaminants because the point of release is feed and generally near the seabed. This report considers the principal types of solid wastes disposed beyond coastal waters~redged material, sewage sludge, and industrial wastes-and potential new sources of wastes that might be considered for ocean disposal in the future. The types of waste disposal that are not discussed are nonpoint and municipal point-source discharges into coastal and estuarine waters and plastics. · Dredged matenals are the single greatest source of solid wastes disposed of in U.S. waters. They range from sands and gravels to fine-grained silts and clays, some of which contain petroleum hydrocarbons, synthetic organic chemicals, toxic metals, and other hazardous substances. Figure 3-6 illustrates the locations of dredged materials disposal sites around the U.S. coastline. Disposal of it; lo. 1 t-r 1~ .~ ~- aP ~ <_~\ 1 . ~ . Dredged Material Dumpsites Low Level Waste (LLW) Dumpsites FIGURE 3-6 Location of waste dumpsites in U.S. coastal waters. SOURCE: I. W. Duedall, Florida Institute of Technology (unpublished).
37 dredged materials on the EEZ seafloor is likely to be broadly distributed around the U.S. coast, with the greatest need associated with major ports and harbors. Most dredge disposal sites are within three miles of the coast, but there are disposal sites in the EEZ, and the~tendenc>,r to locate sites farther from land is increasing. · Sewage wastes are introduced into the ocean in the vicinity of major coastal cities. Sewage sludge has been discharged from pipelines and dumped in the ocean off the mid-Atlantic states for years. Sludge is still being discharged from pipelines into the Southern California Bight and off Hawaii. New York City and municipalities in northern New Jersey and western Long Island dump sludge at the Deepwater Municipal Sludge Dumpsite (DMSD) 120 nautical miles southeast of New York City. Sludge is a major source of DDT and PCBs, and contaminants have become incorporated into the sediments near previously used disposal sites off New York and Delaware Bay (Lear and O'Malley, 1983; Sawyer and Bodammer, 1983; Stanford et al., 1981~. Organic contaminants in New York Bight sediments attributed to sludge dumping are summarized in Table 3-5. TA]3LE 3-5 Distribution and Sources of Organic Contaminants in New York Bight Sediments Concentrationsa C"g/g-~) of four organic substances at four locations and in sewage sludge Material Dieldrin Total DDT Total PCBs Total PAH Sediment Christiaensen Basin7160 0.76,000 Dredged material dumpsiteN.S.9 0.4N.S. Sewage sludge dumpsiteN.S.120 21,100 Outer bightN.D.N.D. 0.000422 Sewage sludgeN.D.1.094 920,400 Concentrations are on a dry weight basis. N.D. = not detected; N.S. = not sampled/analyzed. bThe New York Bight is the region of the continental shelf off Long Island and New Jersey. B. Annual input (kg yet) of organic compounds from dredged material and sewage sludge Source DDT PCB PAH Dredged material65 Sewage sludge106,231 3,500176,000 600-2,0004,100 SOURCE: O'Connor et al., 1982
38 · Industrial wastes have been disposed of principally in the New York Bight, and have included primarily acid-iron wastes dumped at the Acid Waste Site in the New York Bight and the Deepwater Industrial Waste Site just west of the DMSD, and drilling muds from offshore oil platforms. Overall, marine dumping of industrial wastes has decreased dramatically since the early 1970s. Particulate loading from drilling muds varies widely, depending on the extent of activity over a geographic area (see Duedall et al. [198S] for studies of drilling mud discharges in marine waters). From 1946 to 1970, containers of low-level radioactive waste (LLW) and other hazardous substances, including obsolete nerve gas and munitions were disposed of in the ocean. During that time, 107,000 containers comprising 4.3 x 1045 Bq (Bq = Becquerel: flux of radiation across a unit area per unit time) of radioactivity were disposed of at 24 sites, with four sites receiving 90 percent of the waste: two off the mid-Atlantic region, one in Massachusetts Bay, and one near the Farallon Islands off San Fancisco. Future candidates for ocean disposal include incineration ash from burned municipal refuse, fly ash, scrubber sludge, and coal ash. Scope of Development The need to use the ocean for dumping could increase in the future as volumes of waste increase, as concerns for maintaining or improving the water quality of estuarine and coastal waters restrict dumping nearshore, and as land-based options become more expensive and restrictive. In addition to increased or continued dumping of those wastes already being disposed of in the open ocean, some new options for ocean waste disposal are being studied and will be discussed in this section as possible future strategies. Finding suitable disposal sites for dredged material is becoming more difficult as land sites become more expensive and as estuarine disposal faces a more restrictive regulatory climate. Although only one-s~xth of all dredged material is currently dumped beyond three miles, that volume is expected to increase in the future as ports and harbors increase maintenance dredging to accommodate deeper draft and larger vessels, and as U.S. Navy homeport projects generate dredged material (NRC, 1985~. For contaminated material, this dumping will depend on improved methods for separating it from uncontaminated material and containing or isolating it. Over the long term, the volumes of contaminated material may be minimized as source reduction practices lessen the industrial and municipal waste input into coastal waters. Land application and incineration of sewage sludge face increasing public opposition and limitations caused by contaminant levels. Further, while the open ocean is considered to be healthy and capable of assimilating some wastes, estuarine and coastal waters that have borne the primary burden of societal wastes have deteriorated. Arguments will be made to maintain an ocean dumping option for sewage sludge in the future. Future ocean dumping will depend on a variety of factors, such as whether the regulatory climate becomes more or less restrictive, economic tradeoffs between transportation costs over greater distances (to the DMSD) versus increased land-based costs, reduction of toxic pollutants in sludge that would make land disposal more attractive, and granting of waivers from secondary treatment requirements to coastal municipalities. Several large coastal municipalities (Baltimore, Boston, Washington, D.C., Jacksonville, Philadelphia, San Diego, San Francisco, and Seattle) want to maintain dumping or pipeline discharges as a potential option; and Orange County, California has proposed discharging of sludge from a pipeline eight miles offshore into deep ocean waters on an experimental basis (OTA, 1987~. The solid waste byproducts of incineration of municipal solid wastes (incineration ash) and electric power plant combustion (fly ash and flue-gas desulfurization sludge) have been proposed as possible candidates for ocean disposal (Duedall et al., 1985~. Combustion ash is not presently dumped in the marine environment, but anticipated increasing quantities will require disposal either on land or at sea in the next decade. Ashes from different combustion sources have different chemical compositions and disposal considerations, and the impact of such substances on marine
39 organisms and the food web will require examination. Leaching experiments on municipal incinerator ash showed quantities of 14 elements leached from the ash (Francis, 1984~. Although many of the leached chemicals are abundant in seawater and would not be toxic to marine organisms, highly toxic organic components, including dioxin and lead, have been found (Benefenati et al., 1986; Benestad et al., 1987~. Although statutory restrictions preclude near-term consideration of ocean disposal of certain hazardous wastes, such as radioactive material, future pressures on land-based repositories may give rise to incentives to explore the use of submarine geologic formations as permanent repositories for some low-volume, highly toxic, and radioactive wastes. One strategy that has already been investigated is engineered placement of containerized high-level radioactive waste (HLW) within soft ocean clay formations in the EEZ (Heath et al., 1983~. Technical and nontechnical constraints for HL`W disposal are likely to prevent such an option for many years, but some LLW disposal may prove less restrictive: for example, disposal of defueled, decommissioned submarine reactor vessels and soils containing naturally occurring radioactivity. Development Constraints Understanding Fates and Effects There is considerable knowledge of physical processes in the marine environment, such as the dilution of wastes resulting from near-field dispersion and the general circulation associated with ocean currents. Also known are many of the chemical cycling processes that occur in the ocean. However, understanding of marine organisms, their life cycles, and population variability is only rudimentary. One main deficiency for developing sound EEZ waste disposal practices is real-time and time-series information about oceanic processes. Time-series data on the cycles and variability in the marine environment and the effects of anthropogenic perturbations are limited, because most technical investigations have been designed to answer specific questions. Yet, whenever it has been available, the accumulation of one or two decades of systematic data in the ocean or the atmosphere is extremely valuable. The following are information needs for managing waste disposal practices in the EEZ: . Sedimentation rates and types of materials responsible for sediment accumulation on the seabed need to be gathered and mapped. For example, suspended sediments from rivers play a major role in some areas; in others, sedimentation is primarily biologically driven. . . Erosion mechanisms need to be determined. Biogeochemical behavior of specific organic hazardous wastes that may become incorporated has not been investigated. · Diffusion and/or advection rates of wastes through the geological medium need to be modeled and validated. Better understanding of the life cycles and variability of marine organisms is needed. · Understanding is needed of vertical transport and food web interactions from pelagic to benthic organisms. Isolating Contaminated Materials Identifying and isolating contaminated from uncontaminated material is a major constraint for ocean dumping of materials such as dredged sediments. One of the first issues to address is the extent and nature of contaminants present. Uncontaminated dredged material can be a resource rather than a waste for disposal. Placed on the seabed, this sediment may be colonized by different communities of organisms than normally occur at the dumpsite. This localized effect may be helpful
40 or detrimental. If dredged material contains substances harmful to the marine ecosystem, the material must be isolated either on land, in coastal waters, or on the EEZ seabed. During the past two decades, there has been an evolution in procedural and regulatory approaches to identifying contaminated dredged material (Kester et al., 1983~. Table 3-6 summarizes four procedures used to establish the presence of contaminants, ranging from relatively simple chemical tests (the Jensen criteria and elutriate procedure) to complex bioassavs required he the 1976 Ocean Dumping Criteria (EPA, 1976~. Bioassay procedures to evaluate sediment contamination (EPA and COE procedures are a_ _ ~- - - 1 ~ summarized in Peddicord and Hansen, 1983) generally result in a statistical statement of the effects of dredged material on organisms different from or similar to those produced by some reference sediment. The test outcome can depend on how it is performed; in some cases it may be difficult to find a valid reference sediment (Kamlet,- 1983~. There are problems associated with pooling and averaging bioassay results for performing statistical tests of the experimental data. The bioassays do not identify which contaminants are responsible for toxicity. If the toxicity is caused by a substance, such as cadmium or mercury, that is prohibited by the London Dumping Convention, other disposal methods would have to be used. The state of Connecticut procedure (Table 3-6) attempts to establish degree of contamination and types of disposal procedures to be used. This approach has advantages over present federal procedures. If a procedure similar to the Connecticut system were to be developed on the federal level, it should extend the chemical criteria to include such substances as petroleum hydrocarbons, PCBs, pesticides, and organic carbon. Methods for isolating contaminated dredged material include using containment structures on land or in coastal regions, and placing contaminated material in a mound on the seafloor and capping it with clean sediments (Morton, 1983~. A mound capped with sand in Long Island Sound remained intact for six months, but after a hurricane the silt cap showed slumping, flattening, and removal of about 2 m of sediment. In some areas, previously excavated borrow pits or natural seafloor depressions are possible containment sites" (Bokuniewicz, 1983~. Many contaminants in harbor sediments are bound to reduced sediment phases that include sulfides and organic matter. If these sediments are moved to an oxidizing environment, the sulfide can oxidize to sulfuric acid and potentially toxic metals can be mobilized. These anoxic sediments should be contained below sea level using a method such as a pit capped with clean material (Kester et al., 1983~. The possibility of seafloor erosion must be considered at such disposal sites. Over the long term, environmental problems associated with contaminated dredged material can be minimized by source reduction practices. Recycling wastes, reduction of sediment transport and erosion into harbors, and reduction of industrial and municipal waste input into coastal regions will result in less contaminated dredged material being generated for disposal in future decades. A major technical constraint to EEZ seabed disposal of dredged material includes needed improvements in methodology used to distinguish contaminated from clean sediments. Contaminated sediment could be handled according to one set of disposal procedures, and uncontaminated sediment can be used as a resource or disposed of separately and at lower cost than contaminated material. Isolation methods within the marine environment, such as mound capping, borrow pit capping, or engineered structures should be used for contaminated material. Improved understanding leading to prediction of erosional processes on the EEZ seabed is needed for long- term prediction of the suitability of such disposal sites. A number of technical questions need to be addressed before subseabed disposal of contained wastes will be feasible. For example, packaging methods for reliable placement need to be devised (one proposed system uses a fleschette, an arrow type penetrator that is robust, heavy, streamlined, and cheap) and models need to be devised and verified that address rates of canister dissolution. Reliable penetration within the seabed will also require knowledge of the geological medium, especially hole closure, the dynamic response to penetration. Research about hole closure behind the penetrator needs to be done for a variety of penetrator shapes and insertion speeds. The U.S. Department of Energy Subseabed Program has studied mid-plate, mid-gyre regions in the deep ocean basins (Heath et al., 1983~; however, these are not representative of most U.S. EEZ regions.
41 TABLE 3-6 Characteristics Used to Clarify Contaminated Dredged Material Procedure Description Year . . . . Jensen A sediment is contaminated if one or more of its properties exceeds a 1971 criteria permissible limit (see limits below). Elutriate A sediment is contaminated if resuspending one part of sediment into four 1973 test parts of water (both by volume), increases a pollutant concentration in the aqueous phase by more than 50 percent. Bioassay A sediment is contaminated if its liquid phase, resuspended particles, or solid 1977 test phases are lethal or result in pollutant bioaccumulation when tested with appropriate organisms. State of Class I: nondegrading to water quality and nontoxic to organisms. Connecticut Class Il: moderately polluted, but suitable for island or marsh habitat designation development and for open-ocean disposal. Class III: contaminated and potentially hazardous. If bioassays show these to be toxic they cannot be ocean dumped; they must be disposed on land or contained at onshore locations. (See classification criteria below) Jensen Cistern Limits Parameter Chemical oxygen demand Total Kjeldanl nitrogen Volatile solids Oil and grease Mercury Lead Zinc State of Connecticut Classification Limit 50 mg g- 1 me g 60 me g- 1.5 mg g- 1 Egg 50 fig g 50 fig g Parameter Class ~Class II Class III Silt and clay (%) Water content (%) Volatile solids (%) Oil and grease (%) Mercury, ~g/g-1) Lead ~g/g-1) Zinc (ug/g-1) Arsenic ~g/g-1) Cadmium ~g/g-1) Chromium ~g/g-1) Copper ~g/g 1) Nickel (ug/g-1) Vanadium c~g/g-1) SOURCE: Kester et al., 1983 1979 60 40 s 0.3 0.5 100 200 10 s 100 200 50 75 60-90 40-60 5-10 0.3-1.0 0.5-2.5 100-200 200-400 10-20 5-10 100-300 200-400 50-100 75-125 90 60 10 1.0 1.5 200 400 20 10 300 400 100 125
42 If the United States is to consider using the EEZ seafloor for disposal of containerized wastes in the future, further follow-up studies at historic radioactive waste dumpsites would be highly informative. The waste drums presently on the seafloor can be viewed as Experiments in progress." Colombo et al. (1983) provided evidence of container and substrate degradation based on in situ rates. The decadal effects of episodic events at the seafloo~current scouring, sediment slumping, and sedimentation can also be examined. Although the evidence to date is limited, it does not show statistically significant radioactive contamination of sediments from the waste drums. Regulation Waste disposal in the ocean (beyond state waters) is regulated by both federal statutes and by U.S. agreement to international treaties and conventions. The following are the principal laws and treaties governing ocean disposal. U.S. Regulations · The Marine Protection, Research and Sanctuaries Act of 1972 (the Ocean Dumping Act as amended) regulates ocean dumping of dredged material, barged sewage sludge, and industrial waste, and prohibits disposal of HLW and radiological warfare agents in the ocean. · The Clean Water Act, National Pollutant Discharge Elimination Systems (NPDES), and the OCSLA cover drilling discharges, under the purview of the MMS and regulation by the EPA. · The Surface Transportation Assistance Act outlines requirements for LLW disposal, however, the United States has not permitted LLW disposal in the ocean for more than ten years. International Agreements · The London Dumping Convention (LDC) prohibits dumping of organohalogen compounds, mercury, cadmium, persistent plastics, petroleum hydrocarbons, HLW, and biological or chemical warfare agents. Many LDC countries believe that subseabed burial of HLW is illegal, and there is a consensus that any such disposal (even if environmentally safe) would need to be regulated under the LDC. · The International Atomic Energy Agency (IAEA) revised the definition of HLW prohibited from ocean disposal in 1986 and developed guidelines and ocean disposal practices for all other radioactive materials. A senator to the convention the United States is bound bv the IAEA's definition of HLW. ~7 Recent events have created a regulatory climate that favors protection of the marine environment. During 1988, commercial and sport fishermen in the north-eastern United States attributed declines in the health and abundance of some shellfish species to sewage sludge disposal at the DMSD, and incidents of hospital medical wastes washing up on beaches from New Jersey to Massachusetts led to beach closures. These events generated considerable political attention, and Congress subsequently passed legislation (Ocean Dumping Ban Act of 1988) designed to prevent continued ocean dumping of sewage from the New York-New Jersey metropolitan region beyond 1991. With the increasing realization that pollutant impacts are regional in scale, rather than local, legislation has been written that addresses marine pollution and research on a regional basis. The March 1989 Moron Valdez oil spill in Prince William Sound, Alaska, further heightened public concern about the fragility of marine ecosystems and the economic impacts of contaminants in the ocean. It is likely that the ocean will continue to be used for dredged material disposal. However, in the near future, resistance to marine disposal of other types of waste (such as sewage, incineration ash, industrial, and radioactive) is expected to grow. There is a clear need for a national policy on waste disposal that emphasizes methods that minimize impacts to the total environment-the air,
43 land, rivers, groundwater, estuaries, and oceans. It is possible that such a polity could result in increased use of the ocean for waste disposal within 10 to 15 years. Improved technical understanding and sound regulatory controls could enhance public confidence that some tones of waste can be disposed of in the marine environment without degrading it. Siting -or More resources and technical expertise will be needed if dredged material dumpsites are to be designated and monitored on a more timely basis during the 1990s than they were in the 1980s. While progress is being made to systematically review and designate dredged material dumpsites, there are large areas of the country where established sites are not available, and only 14 percent of the sites being designated by the EPA have received final designations after more than 10 years of work (Table 3-7~. A systematic EEZ data base and improved understanding of long-term predictability of seafloor erosion processes may contribute to speeding up the designation process. TABLE 3-7 Summary of Dredged Material Dumpsite Designation Status as of 1987 Located in EPA Regions and Associated with Various Coastal States State EPA Region Pending Proposed Final . . Maine I 2 0 0 New Hampshire I 1 0 0 Massachusetts I 2 0 0 Rhode Island I 0 0 0 Connecticut I 0 0 0 New York II 4 0 1 New Jersey II 4 0 0 Puerto Rico I] 6 0 0 Delaware Ill 0 0 0 Maryland III 0 0 0 Virginia IlI 2 0 0 North Carolina IV 2 0 0 South Carolina IV 2 0 0 Georgia IV 2 1 0 Florida IV 16 9 2 Alabama - IV 1 0 0 Mississippi IV 3 0 0 Louisiana VI 23 0 0 Texas VI 5 0 1 California IX 11 0 2 Hawaii IX 3 0 0 Pacific Islands IX 3 0 0 Oregon X 9 0 3 Washington X 3 0 4 Alaska X 3 0 0 Total Number of Sites 107 10 19 SOURCE: U.S. EPA
44 The-EPA has conducted a number of efforts to evaluate disposal siting for sewage sludge and industrial wastes (Reed and Bierman, 1989~. Consideration has been given to an ocean incineration site off the east coast (OTA, 1986~. Most presently used ocean dumping and pipeline discharge sites have been located based on historical practice and proximity to the waste source. Public Perception Public perception has developed into a major category of nontechnical constraint on using the marine environment as a waste disposal medium. The socioeconomic tradeoffs of disposing of waste on land~vhere it poses a serious hazard to groundwater, freshwater lakes and rivers, and the rich nearshore environment of bays and estuaries-have been given far too little attention in risk assessments of marine waste disposal. Summary Over the past ten years many waste disposal practices in the ocean have been phased out, and while seafloor disposal of dredged materials will continue, public and political opposition is likely to uphold restrictions of ocean dumping of sewage and industrial wastes. Future use of the EEZ seabed for waste disposal will hinge on socioeconomic pressures, innovative engineered approaches to ocean waste disposal and better understanding of the mobility of contaminants. CABLES AND MILITARY USES Baclcground The ocean environment and the information needed to install and implement protective measures for submarine cables in the EEZ are common to many military uses. For this reason, these two uses are addressed in the same section. Cables Communication cables carrying voice and data transmissions constitute the majority of ocean cable installations-approximately half of all overseas communications are transmitted through ocean cables installed on the seabed (Federal Communications Commission [FCC], 1988~. They can be transoceanic or intraoceanic and perform-diverse functions. There are toll systems constructed by communications common carriers; private systems, such as those used in the offshore oil and gas industry; or dedicated cables for transmission of military information. With the rapid development of fiber optic technology in the 1980s, the medium of choice shifted from satellites to cable (Table 3-8~. The introduction of digital services by Intelsat International Business Service in 1986 led to a soaring demand for digital and higher quality service, as users dealt with Rain fade" and 0.25-second propagation delay inherent in satellite transmissions. One implication of the rapidly increasing capacity of these facilities is that the revenue per minute lost due to a cable fault is also increasing and true economic cost of interruption to the user must be considered. The greatest potential hazards to these cables are bottom fishing trawlers and natural downslope processes, such as slumping and sediment news. Armoring of cables has helped somewhat in combatting cable faulting by trawl gear, although fisherman often cut away lightly armored cables to free their gear. For example, in one such incident, the TAT-8 cable suffered major disruptions in
45 TABLE 3-8 Transatlantic Cables and Capacity Facility type Year in Capacity (voice circuits) Dual coax cable 1956 50 (3kHz) Dual coax cable 1959 48 (3kHz) Single coax cable 1961 80 (3kHz) Single coax cable 1963 138 (3kHz) Single coax cable 1965 138 (3kHz) Single coax cable 1970 845 (3kHz) Single coax cable 1974 1,840 (3kHz) Single coax cable 1976 4,000 (3kHz) Single coax cable 1983 4,200 (3kHz) 2 x 280 Mbit/sa fiber 1988 7,560 (64 kbpsb) 3 x 420 Mbit/sa fiber 1989 18,144 (64 kbpsb) 2 x 560 Mbit/sa fiber 1991 15,120 (64 kbpsb) aMbit = Megabits per second bkbps = Kilobits per second SOURCE: National Telecommunications Information Agency, 1984. service due to fishing activity in early 1989 (Anon., 1989~. Burying the cable in the ocean bottom has been an effective countermeasure against trawling damage. Current burial methods include plowing and trenching of cables as they are being installed, or jetting-in of previously installed cables. In addition, directional boring has been utilized to minimize environmental damage where cables cross beaches, dunes, and barrier islands. This technique also reduces the probability of anchor fouling by placing the cable in a steel pipe, meters under the seafloor. Military Uses The military utilizes the EEZ as an operational arena, as a laboratory for researching, developing, testing, and evaluating operational systems and techniques, and to train personnel. Military missions take pre-eminence in the ocean in times of conflict, but this position is less readily accepted in peacetime and is subject to more careful review to balance military, commercial, and ecological considerations. Epically, when a planned commercial venture within the EEZ potentially conflicts with military objectives, the matter is negotiated between the Department of Defense and the federal agency that has regulatory oversight for that commercial undertaking. For example, oil leases are selectively awarded to minimize interference with military operations in or near the lease field. Conversely, the military may seek alternative means of obtaining their objectives if existing commercial operations conflict with the development of military operations. Co-existence of military and commercial ventures relies on sharing knowledge about planned or existing activities to anticipate potential conflicts. The degree to which such sharing is possible, however, may be restricted by national security and commercial proprietary interests. Because military interests in the EEZ cover a broad range of activities-from cable and sensor installations to supporting research and development concerned with physical, mechanical, and
46 acoustical properties of sediments-this section will identify activities that have technical elements in common with commercial developments or pose potential conflict. In addition to seafloor uses, naval operations on the surface-such as firing ranges, transit lanes, and test ran~es~an also interfere with the availability of the proximate seafloor for other uses. The following are widespread military uses that can be expected to continue into the future: 1. Submarine cable systems are used for voice and/or data transmission among shore-based facilities and between sensors and shore-based processing facilities, and to transmit power and control signals. 2. Sensors and transducer systems of various types are deployed on and above the seafloor to support research and development activities; to test and evaluate ships, submarines, aircraft, and weapons systems; and as integral parts of tactical and strategic monitoring systems. 3. Moonng systems are required for surface and midwater devices, such as ships, surface instrumentation buoys, and subsurface to near-bottom instrumentation pressure vessels. 4. Remote) operated (ROVs) and autonomous underwater vehicles (Arms), used for research and development and tactical operations, are normally used within the water column, but may include deployments of bottom crawlers as well. The military has become a major user of ROVs and AUVs. 5. Asset disposal includes dumping of surplus, outdated, and hazardous defense materials and equipment on the seabed. Although ordnance (explosives) is no longer dumped on the seabed, previous sites may still contain dangerous materials. Naval vessels are disposed of at sea in a variety of forms and for different reasons, including bombing or artillery practice, formation of artificial reefs, or nuclear-powered vessel disposal. 6. Mine warfare in times of conflict can benefit from highly detailed bathymetric charts used to fingerprint areas of significance. Navy efforts to provide such fingerprint data are closely related technically to commercial and research requirements for detailed bathymetry. 7. High-powered, low-frequency active sonar systems for antisubmarine warfare (ASW) and mine hunting applications must contend with the seafloor as an acoustic reflector. Acoustic reflectivity mapping and research aimed at improving the predictive capability of reflectivity models provide an important data source for enhancing ASW operations. 8. Finng ranges are remote areas reserved for use as firing and bombing practice, and are excluded from either research use or commercial development. 9. Acoustic test ranges are instrumented test ranges covering many square kilometers of ocean set aside for a variety of acoustic tests. Other seafloor uses in these ranges are extremely limited. 10. Submarine transit lanes along the seafloor exclude commercial exploitation of oil, gas, and mineral resources. Scope of Development Cables Despite communications satellite development, economics and security have provided the impetus for the continued use and planned extension of ocean cable systems (Figure 3-7~. In addition, because of the relative vulnerability of satellites, the military is reassessing its position of substantial dependence on satellite communications for land-based facilities. In the next 10 years, the development of fiber optic cables with wider transmission bandwidth will reduce the number of active cables in use for a particular link. However, over the next 25 years, the number of cables is likely to increase as links to other continents and islands become more cost effective, due to improved economy per unit length of fiber optic cables. An additional advantage of fiber systems is that they can have multiple landings; each pair of fibers in a transoceanic fiber cable can have a separate landing point. For example, an existing fiber
47 , ~ O'er ! 5, j Jo 30/i: D: 0 ~ Mariana 20~ \~,j,` Islands 605< ~, Midway Island Wake ~ it/ 10°N~ // / Palmyra Atoll/ _ /\; Kingman Reef Id Howland and i', ~ / /_` ~ ~Baker Islands \ ; ~ ~ Jarvis Island 10 j} ~t `/ ~American \C \ \ - \ \ ~ ~ / 1 1 20°E 1 50°E 0° ~ l 180° ~0 /~\ ~ ,, . ~ ~ ', Bermuda: ,./ ~ United States i \ Puerto Rico/ ~ B/ hamas Virgin Islands / - - ~ STM-SAN `< ~ Jamaic )_~/ Marteen -~0°N 0 2000 Km 1 , 1 n 1nnnNM 1 oo , ~v tvvv~v ~1 /_ ` ~Samoa I ~/1 0°S 1 1 1 1 1 1 1 1 1' 1 \1 I I 1 50°W 120° 90° 60° FIGURE 3-7 Major commercial communications submarine cables passing through the EEZ. Optic cable has only one U.S. landing, but it branches 200 km offshore for a 1,200-km spur running to Bermuda. Another major shift in commercial communications is the introduction of facilities competition. Transoceanic facilities are no longer the sole province of existing telecommunication monopolies. Private companies are building facilities on the assumption that traditional forecasting methods have resulted in a shortfall in capacity over the next five years. Recently installed cables in the Atlantic and Pacific oceans are examples of this new facilities provider. In the immediate future, fiber optic cable systems will cause coax cables to become obsolete on high traffic density routes, resulting in fewer active cables. However, rapid growth in digital traffic means that more fiber cables are being planned. Therefore, the number of very high-capacity, high- revenue fiber cables will grow. Table 3-9 shows the capacity of existing and planned submarine fiber optic cables, and likely developments based on other recently announced cable systems. Ongoing development in halide fiber technology presents an enticing vision of repeaterless, transoceanic fiber optic systems. (Fluorine- or chlorine-based glass, if pure, has an extremely low attenuation curve in the infrared frequencies.) Researchers at the Naval Research Laboratory estimate that this will be possible in 15 to 25 years. To protect cables against trawl gear damage, approximately a dozen commercial and several military cables have been buried on the U.S. continental shelf to a depth of a third to half a meter. Future cable system plans include protective burial, where possible, from the beach landing to the point of entry to deep water (relative to trawling hazards to cables, this is usually defined as 900 m, and is extended to 1,300 m in some cases). As more powerful trawl rigs are developed, the range and depth of bottom trawling will expand. l
48 TABLE 3-9 Submarine Fiber Cables Year in Capacity Facility type service (voice circuits-64 Kbps) 2 x 280 Mbit/s fiber 1988 7,560 2 x 280 Mbit/s fiber 1988 7,560 2 x 280 Mbit/s fiber 1989 7,560 3 x 420 Mbit/s fiber 1989 18,144 3 x 420 Mbit/s fiber 1990 18,144 2 x 560 Mbit/s fiber 1991 15,120 2 x 560 Mbit/s fiber 1991 15,120 2 x 1,800 Mbit/s fiber 1991 36,000 Military Uses Since the EEZ waters are central to U.S. defense, a significant military role in the following areas will continue and grow as technology advances. . . Ocean cables: Because ocean cables provide an economical and secure means of transferring data over long distances, installation of cables will grow in the future. Fiber optic technology will enhance ocean cable application, and cable connectivity, especially for remote areas, will be more complex. __ - r ~ · . · ~ · , -A ~ ·- . - r ~ ~ . _ _ _ ~ _ _ __ A__ ~ _ censors ana transducer systems: ~clenurlc appllcauons or sensors and Iransaucers oy Ine military have increased, and as the technology upon which they are based has advanced, their reduced cost and greater capabilities stimulate use of a greater range and number of sensors. Improved characteristics and capabilities of naval platforms result in increasingly greater numbers of tactical and strategic sensor systems. Anticipated ten- to twentyfold expansion of military ranges in the EEZ in a few years will also increase the number of sensors used. · Moonng systems: Advancing technology is making a wider range of moored devices possible and more affordable, thus increasing the need for mooring systems. Although the moorings in many cases are small, the number and spatial range in any undertaking tends to grow with advancing technology. · Remotely operated vehicles and autonomous underwater vehicles: The application of ROVs and AUVs to military tasks is in its infancy relative to the potential of these vehicles for solving many problems associated with accomplishing underwater tasks, and military investigation of this potential will yield vehicles capable of performing increasingly complex tasks, some of which will use the seabed as a working surface. Military development of these vehicles for installation and support of complex mechanical structures in deeper water will well outstrip corresponding commercial development. . Asset disposal: Although disposal of ordnance at sea has ceased, disposal of defueled, decommissioned nuclear-powered submarines is an increasing concern. The disposal of nuclear- powered submarines presents a challenge to achieve safe disposal through conventional reclamation procedures. Therefore, the submarine is usually disposed of by sinking the defueled, decommissioned boat to the seabed at a position deemed as having minimum impact on the environment.
49 Constraints to Development Geophysical Constraints Geological processes and the composition of the substrate are the most dominant physical constraints on emplacement and maintenance of ocean cables and military uses. Some of these considerations are summarized below. · Seismic tectonic activity: Special design criteria and considerations are necessary where seismic activity causes ground motion that can damage cables or other bottom-mounted structures. · Seafloor instability: Routing of cables and placement of structures are affected by downslope mass wasting processes (debris flows, turbidity currents, and slumps and slides), which cause movement and eventual failure of cables and other structures on the seabed. Rerouting of cables and selective placement of structures to avoid these hazardous areas are often required. · Sediment transport dynamics: Where sediment transport and scour processes are active, cables may need to be buried or rerouted. Bedload movement and the development of bedforms can expose previously buried cables, resulting in strumming (vibrations set up by hydrodynamic forces), reduction in support, and ultimate failure. Additional research and field data are needed to more accurately model interactions between currents, the seabed, and the cable. · Ice gouging In high-latitude regions cables must be buried deep enough to protect them from gouging by sea-ice keels. · Subsea permafrost and gas hydrates: Not only is burial difficult in permafrost, it provides a thermally unstable environment that can result in differential collapse of the substrate and eventual failure of cables. · Bottom topography: Submarine cable routes are directly determined by ocean bottom topography. Extreme rates of change in depth may require detouring to avoid excessively long segments of suspended cable, where currents cause the cable to strum. For extreme lengths, suspended cables can break under their own weight. Seafloor structures and acoustical performance of sensor systems are all affected by bottom topography. Excessive variances can create azimuthal blockage of acoustical transmissions. · Acoustical properties of the ocean bottom: These are directly affected by substrate composition and are important in developing sensor systems. · Traf~cabili~ of the seabed: As ROVs and AUVs become more common for underwater tasks, trafficability of the sea bottom will become an important factor as "bottom crawlers," which depend on the seabed for support and traction as they maneuver, are introduced to military applications. Use Conflicts A major issue in the development of military uses of the seabed is the conflict between military applications and commercial, recreational, and environmental interests. The most intrusive situation by the military, as viewed by civilian interests, is the exclusion of civilian uses from military areas for safety, interference, and security reasons. Fishing activity, dumping, and historic sites also preclude certain activities. Figure 3-8 illustrates various uses of the sea and how they impact the installation of a cable. Avoiding existing hazards is the responsibility of the cable system developer. Managing relations with fishermen to avoid deploying systems in areas with significant fishing activity is a key factor. Since commercial fishing activity moves from one area to another over time, cable operators must also work with fishermen to reduce the probability of a trawl striking the cable. The bottom trawling fishing industry uses gear that are often incompatible with the protection of ocean cables and sensor/transducer systems. Although ocean cables can be buried, some sensor
so \ \ \ \ \ Sewe Outfal / /'] J / // / / I E3 Fish Trap Area ~ Chemical Dump FIGURE 3-8 Hypothetical use conflicts for underwater cables. Trawling Ground Radioactive Waste Incineration Site Construction Debris Explosives Dump and transducer systems cannot be buried, either because of their mechanical configuration or mission performance criteria. Fishing gear can also tangle with moored devices, resulting in damage to gear or mooring or both. Restricting areas around moored devices is a protective alternative. Areas designated for mineral extraction may exclude the routing of cables, or, conversely, mining may not be feasible in heavily impacted areas of cable installations. Oil exploration activities may directly conflict with the effective performance of some tactical sensor systems. For example, seismic profiling for resource exploration represents an extreme form of acoustic pollution to an acoustic surveillance system. Countering these noise sources requires equipment with greater dynamic ranges and a substantial data processing investment. This interference with sensor systems produced by oil exploration seismic profiling and any other noise generators will constrain further development of these sensor systems. The U.S. Navy has recently explored these issues with the Western Oil and Gas Association. Summary Future growth in the number and value of ocean cables is assured by the soaring demand for digital transmission using fiber optics, which have produced more reliable, economical, and secure telecommunications. There is also every reason to believe there will be an increased military presence in the EEZ because the nation's defense depends on military activities carried out in these waters. Continued advances in technology that enhance defense capabilities will find application in the EEZ. But submarine cable systems will continue to face serious risk of interruption presented by geophysical processes and conflicting uses or restricted access. Additional research and field data
51 are needed to more accurately model the interactions between currents, the seabed, and cables for more effective protection (burial), and to prevent strumming of exposed cables. Technology is needed for more effective geotechnical survey and data interpretation and more cost-effective and reliable burying systems during and after installation. BIOLOGICAL RESOURCES Background Living resources associated with the benthic boundary layer fall into one of two categories in this report: commercially important fishery resources and organisms of special scientific interest or of potential importance as biotechnological or genetic resources. A third category of organisms (discussed in Chapter 2) are those of little or no direct economic importance, but whose roles in seabed processes must be considered in the context of other existing or potential seabed uses. The United States is one of the world's largest consumers of seafood products: 1987 per capita consumption was 15.4 pounds (edible weight), a record high (O'Bannon, 1988~. Commercial imports reached a record $8.8 billion in 1987, a 16 percent increase over 1986, and exports were a record $1.7 billion, a 22 percent increase. A large portion of the $6.1 billion trade imbalance in fishery products is attributed to aquaculture products, which are being produced in greater numbers in foreign countries. Domestic aquaculture operations are generally restricted to coastal waters and significant expansion beyond three miles into the EEZ seabed is unlikely and is therefore not discussed in this report. U.S. EEZ commercial fish and shellfish catches from 1982-1987 are summarized in Table 3-10. Foreign vessel catches have declined dramatically: the 1987 total foreign catch was 150,000 metric tons, only 13 percent of the average for the preceding five years. Only 8,400 metric tons (6 percent) were seabed finfish and shellfish species. U.S. vessel landings increased gradually over this period, and joint-venture catches (U.S.-flag catches transferred to foreign vessels) increased sharply. The total EEZ catch has not changed markedly over this six-year period, mirroring the overall world catch (O'Bannon, 1988~. The 1987 catches of seabed-associated species (Table 3-11) are combined landings by U.S. vessels and joint venture catches. Excluding species that include aquaculture products (clams, oysters, scallops), the catches of bottom species (shrimp, crabs, lobsters, and flounders) rank second through fifth in value of all species caught in the U.S. EEZ in 1987, exceeded only by salmon. TABLE 3-10 Commercial Catches (Metric Tons) in the U.S. EEZ Foreign Landings by Joint venture Year vessels U.S. vessels catches Total 1982 1,410,000 820,000 230,000 2,460,000 1983 1,320,000 730,000 430,000 2,480,000 1984 1,340,000 680,000 680,000 2,700,000 1985 1,140,000 770,000 910,000 2,820,000 1986 590,000 1,140,000 1,320,000 3,050,000 1987 150,000 1,180,000 1,590,000 2,920,000 SOURCE: O'Bannon, 1988.
52 TABLE 3-11 Catches of Seabed-Associated Species by U.S. nag Vessels in 1987 0-3 mile offshore zone 3-200 mile offshore zone weight value weight value (metric tons) ($million) (metric tons) (million) Shrimp 79,500$ 264.9 85,300$ 313.2 Crabs 106,500123.3 68,700198.5 Lobsters 17,900112.9 5,30041.6 Flounders 27,60024.9 284,000148.0 Halibut 12,30030.7 22,20057.5 Clams, oysters, scallopsa 35,500197.2 62,000172.4 Total 279,300$ 753.9 572,500$ 931.2 aIncludes aquaculture SOURCE: O'Bannon, 1988 Within the last ten years, new species of marine organisms have been discovered in the EEZ seabed where geological and chemical processes result in zones in which chemically reduced compounds mix with oxygenated bottom waters. For example: · the subduction zone off Oregon, where pore waters enriched in natural gas (methane) and probably hydrogen sulfide are squeezed out of the accretiona~r wedge; O ~. ~ ~ ~ ~ ~ _ , · oil- and gas-producing regions on the Louisiana continental slope, where methane and hydrogen sulfide are released from the sediment; · the Florida Escarpment, where thermochemical reactions at depth appear to be responsible for producing hydrogen sulfide-rich hypersaline brines; and · the Gorda Ridge off northern California and Oregon, where active hydrothermal vents occur. In these locations, unique animals have been found living symbiotically with bacteria that utilize the chemical energy in hydrogen sulfide. These characteristics suggest that such organisms may have important potential applications for biotechnological or genetic engineering. Scope of Development Although most fisheries experts believe that traditional fisheries are at or near maturity, there are opportunities to develop nontraditional seabed resources. Some resources of the continental slope can be harvested by extending existing technology into deeper water. Deepwater crab and ocean perch fisheries, for example, will require only minor technological modifications. Bacteria capable of using chemical energy for growth have been known for many years (for example, bacteria that grow on simple, one-carbon compounds such as methane have been the
53 subject of research on the production of single-cell protein), but previous research has concentrated on terrestrial-based free-living bacteria. Only recently has the symbiotic association of such bacteria with higher organisms been elucidated (Cavanaugh, 1983~. The consequences of these discoveries for genetic engineering and biotechnology may be substantial, insofar as these animal-bacterial symbiotic pairs have solved the problem of passing bacterially produced carbon compounds directly to the cells of the host animal. These findings take on added importance in light of the toxicity of hydrogen sulfide and hydrocarbons to most organisms. Animals living in these locations have evolved biochemical mechanisms to avoid toxicity, thus their study is of considerable physiological significance and warrants investigation (Felbeck and Somero, 1982~. Additionally, many bacterial species found in chemically unusual marine environments are logical candidates to study for their ability to degrade toxic chemicals (Jannasch, 1989~. Discoveries of microorganisms with the ability to metabolize chemical compounds previously thought to be resistant to biodegradation have stimulated the search for additional microbes with such desirable abilities (Roberts, 1987~. The use of natural products as pharmaceutical agents in the treatment of cancer, AIDS, and other diseases is receiving renewed interest from the National Cancer Institute (Booth, 1987~. Many marine benthic invertebrates are potential sources of such drugs. Although it is impossible to predict which organisms are likely to produce substances of medical value, organisms that have adapted to unusual conditions, such as those discussed above, are worthwhile candidates. Given the rapid pace of advances in isolating and cloning genes, it is difficult to estimate time frames for biotechnical development of genetic resources. In the past, screening organisms for the presence of compounds of possible pharmaceutical or commercial activity was haphazard. However, the Natural Products Branch of the National Cancer Institute has initiated a five-year program to search more systematically for drug candidates derived from various organisms, including marine invertebrates and blue-green algae (Booth, 1987~. An example of a potentially valuable natural product is didemnin B. an extract from a benthic tunicate that is being tested in clinical trials against a variety of human cancers. Development Constraints Increased utilization of wild stocks from the new regions of the EEZ will require confronting the longstanding problem of assessing population sizes. The abundance of fishes and invertebrates in topographically complex regions, such as banks, escarpments, and seamounts, are difficult to assess because these environments inhibit conventional sampling techniques, preventing accurate estimates of population size. Newer techniques based on ROVs, better sensors, acoustics, and improved data interpretation may alleviate present assessment problems. High-frequengy acoustical profiling techniques, for example, have detected high abundances of krill (euphausiids) in the benthic boundary layers of submarine canyons off Georges Bank that may be important food sources for commercial fisheries (Greene et al., 1988~. Use conflicts between defense operations, cables, and fishing gear may also inhibit fishing development. One such conflict arises over the need to provide safe navigation lanes for submarines. These lanes are well established, but fishing vessels tend to ignore them and enforcement efforts have been ineffective. Another conflict exists between bottom trawl gear and Navy underwater surveillance installations. Although the Navy has buried cables in trawling areas in the past, planned expansion of undersea surveillance installations could exacerbate this use conflict, potentially leading to the prohibition of bottom trawling in certain areas. Commercial transoceanic telecommunications installations pose a similar conflict. A number of seabed trawlers have reported fouling of underwater cables and fishing gear resulting in damage or loss to both cables and trawls. Underwater cable routes are marked clearly on the navigation charts, but general compliance does not exist and enforcement has been ineffective. Other seabed uses-oil and gas development,
54 mineral extraction, and waste disposal-pose additional potential conflicts in the absence of established use priorities. Development of nonfishery living resources will require characterization of benthic communities throughout the EEZ before potentially invaluable species are lost due to habitat alteration by other uses. The National Cancer Institute's program for identifying and collecting organisms with promise for supplying pharmaceutically active compounds (Booth, 1987), is primarily focused on tropical plants and coral reef invertebrates because these environments are rapidly disappearing or being altered. Benthic organisms that occur in seafloor areas with commercial utility (i.e., hydrocarbon seeps on the Louisiana continental shelf) or with potential economic value (i.e., polymetallic sulfides on the Gorda Ridge) are not presently included in this screening. So far, only a few species have been screened, and increased extinction rates of many rare species caused by habitat disruption could deprive the medical and scientific community of valuable sources of natural products. Summary EEZ biological resources are extensive and represent important sources of food and potentially valuable medical products. Information on their diversity, abundance, and occurrence is limited, however. The yield from traditional fisheries, using present technology, is at or near its upper limit and improving fisheries yields will depend on improved forecasting and stock assessments in topographically complex and deepwater regions to assess the potential for expanded fisheries. The potential for establishing the value of exotic organisms will hinge on the pace and extent of inventorying these resources and maintaining biodiversity in the oceans. OCEAN ENERGY RESOURCES Background Ocean energy resources-thermal energy, waves, tides, currents, salinity gradients, biomass, winds, and seafloor geothermal-and related technologies are in very early stages of development, and the extent to which they will make significant demands on the EEZ seafloor is difficult to estimate. Nevertheless, it is possible to consider possible effects and tentative information needs associated with ocean energy development. Not all potential ocean energy resources exist at all locations around the U.S. shoreline. · Ocean Thermal Energy Conversion (OTEC) requires a substantial temperature difference between warm surface water and cold deeper water and a nearshore steeply sloping seafloor, conditions that are found off Puerto Rico, the Virgin Islands, and Pacific islands (Figure 3-9~. Waves exist in all coastal locations but appear most suitable along the eastern seaboard. The ocean current most accessible to the United States that appears to be the best candidate for power generation is the Florida current off Miami. · Tidal power is most efficiently produced where the tidal range exceeds 5 m, either off eastern Maine or in Cook Inlet, Alaska. · Salinity gradients exist principally at the mouths of large rivers. · Biomass production requires a good nutrient supply, cold water temperatures, and adequate sunlight-conditions met off the south and central California coast. · Ocean winds exist all along the U.S. coast but are most persistent off the northeast coast. With the exception of OTEC and possibly wave energy, it is unlikely that these technologies will have a significant impact on U.S. energy supplies or require placement in the EEZ. Tidal power installations, given their need for embayments, enclosures, or ponds, will not involve the EEZ or its
55 20 CD llJ - c, EC on 1 60W 140 120 100 80 60 40 20 0 20E 40N 20 CD IL - LL EO 20 40S 40E 60 80 100 120 140 160 180 160W LONGITUDE/DEG FIGURE 3-9 Worldwide distribution of the ocean thermal resource. Contours are for the annual averages of monthly temperature differences (in degrees Celsius) between the ocean surface and depths of 1,000 m: (top) the Western Hemisphere, (bottom) the Eastern Hemisphere. The black areas in coastal regions indicate water depths less than 1,000 m. SOURCE: Cohen, 1982 seabed. Salinity gradient power, and most other ocean energy sources generally will require relatively shallow coastal waters and, probably would be located within the territorial sea. Scope of Development OTEC involves harnessing the temperature differences between surface and deeper waters and converting them to energy. A closed system version vaporizes a working fluid using warm surface water, which expands under high pressure to run a turbine, and is then recondensed by deep cold water. The open-cycle system uses sea water as the working fluid and produces fresh water as a byproduct. OTEC requires a 20° C or greater temperature differential between surface and deep water. In a shore- or shelf-based system, the deep cold water must be relatively close to the beach. An OI~EC system with potential EEZ applications is an at-sea floating facility with a pipe suspended to the deep Goldwater supply. Because of engineering problems associated with the suspended
56 Goldwater pipe, electrical power riser cables, and deepwater mooring, attention has been focused on onshore or nearshore bottom-mounted facilities with a Goldwater intake pipe resting on the sloping ocean floor. Floating systems could still become feasible in the future (beyond 10 to 15 years), however. In 1979, a small-scale, barge-mounted OTEC plant model moored off Hawaii (mini- OTEC) produced a small amount of power for a few weeks, thus confirming the validity of the principle (Cohen, 1982~. U.S. OTEC interest has focused on Hawaii, Guam, the Virgin Islands, and Puerto Rico, with the work in Hawaii being the most advanced. The state of Hawaii, the U.S. Department of Energy, and the Pacific International Center for High Technology Research have combined resources to build a pilot OTEC plant at Hawaii's Natural Energy Laboratory (NELH) at Keahole Point. The system includes the production of nutrient-rich, pathogen-free cold water for aquaculture and an open-cycle OTEC system for generating electricity. The NELH project consists of five, 40-inch-diameter Goldwater pipes in a 1,800-m system that can pump fluid from a depth of 660 m at a rate of 13,000 gallons per minute. The Goldwater pipe represents a significant technical challenge. It must be sufficiently long for its intake to reach the cold depths of the ocean, and it must have a diameter large enough to accommodate the flow of massive quantities of water (Rogers et al., 1988~. Extracting energy from ocean waves has been discussed for years by the British, Japanese, and Norwegian governments, and many wave energy devices have been proposed (McCormick, 1981~. A consensus has developed around the oscillating water column approach, in which the motion of water within the wave energy conversion device acts as a piston, compressing the air and forcing it through an air-driven turbine connected to a generator. Such devices can also serve as breakwaters, reducing costs to a very competitive figure, as low as 4 cents per kilowatt hour. This concept is reportedly being tested in a five-megawatt prototype system under construction in the Scottish Hebrides Islands (Baggott and Morris, 1985~. Although more wave energy is available in the deeper offshore waters, the system is being built in only 21-m depth because its designers have not found a way to permanently anchor a structure big enough to provide commercially useful energy supplies, while at the same time it is able to withstand maximum interaction with incoming waves. In late 1988, agreement on a wave energy project was reported between the kingdom of Tonga and the Norwegian government, who agreed to build and install a three-megawatt wave-generating facility in Tonga. Based on such recent developments, it is reasonable to predict that a number of wave energy projects will be built within the next 10 to 20 years. However, it is impossible to predict if and when wave energy conversion systems will be operated in the deeper waters of the EEZ. Higher wave energies make offshore operations attractive, but the problems of mooring and energy transmission to the mainland will undoubtedly retard such developments. Development Constraints OTEC could place technically significant demands on the EEZ seafloor. A commercial-scale shore-based facility would require a very large pipe (or tunnel) to supply cold water that will need to follow a sloping seafloor down to a depth of as much as 1,000 m to find seawater 20° C colder than surface water. The fixing of such a pipe (which could be as large as 9 m in diameter and 5,000 m long for very large-scale applications) to a steeply sloping seafloor will be technically demanding, and will require a wide range of seafloor information (Rogers et al., 1988~. The most important information will pertain to properties of the upper continental slope: strength and stress-strain time parameters, compressibility and stress history, permeability, effects of slope deformation and failure, landslides, turbidity currents, debris flows, faulting, erosion, and scour. Site-specific information will be needed on nearshore properties to successfully "fastens large Goldwater pipes to a sharply sloping seafloor (Lockwood and McGregor, 1988~. Floating and moored OTEC facilities and wave energy facilities will require information on the seafloor properties needed to construct safe and reliable mooring or anchoring systems. In some
57 configurations, the electrical energy would have to be transmitted to shore by seafloor cable, creating a need for detailed seafloor information along the cable route. Summary lathe development of ocean energy systems in the U.S. EEZ during the next 10 to 20 years depends on the potential economic advantage in specific areas where it is feasible. The most promising technolog~OTEC-is limited to subtropical and tropical areas where there is an adequate temperature differential and accessible deep ocean water. Higher oil prices will be the crucial factor driving the development of these technologies. Although wave evergy systems are being developed in Norway, Japan, and the United Kingdom, there is little interest in these systems in the United States. It is likely that islands with appropriate wave climates and high existing energy costs (Pacific islands qualify on both counts) will be the first places considered for wave energy systems, if they become commercially viable. Of the two technologies, OTEC will have more demand for EEZ seafloor information since wave energy systems will almost certainly be located on or near the shore. CULTURAL AND RECREATIONAL RESOURCES Background Cultural and recreational resources of the EEZ include marine archaeology, treasure seeking, and commercial salvage; recreation; and marine sanctuaries. . Marine archaeology, treasure seeking) and commercial salvage: Marine archaeology is a very small and relatively stable activity (perhaps no more than 100 individuals in the United States), but treasure seeking and commercial salvage are substantially larger and more visible. Commercial salvers, excluding treasure seekers, seek to retrieve hulls or cargo of recently sunk vessels. Their activities are regulated under maritime law, which asserts that abandoned shipwrecks and other items on the seafloor become the property of the "finders. · Recreation: Seafloor habitats are becoming underwater attractions in some coastal locations with large tourist populations. This trend will probably accelerate as the popularity of coastal and ocean recreation grows. · Manne sanctuanes: Ocean areas of special interest, uniqueness, value, and importance are the wet counterparts of national parks and forests, wildlife preserves, and historical monuments. They are set aside to protect unique recreational amenities (coral reefs), cultural sites (historic shipwrecks), habitats or wildlife areas, or valuable research sites. Most of them remain to be discovered, so a probable growing activity in the EEZ will be identifying and designating such areas for long-term protection. The approach usually employed is designation as a marine santuary under the Marine Protection, Research, and Sanctuaries Act (MPRSA). Eight marine sanctuaries have been designated so far: the U.S.S. Monitor off North Carolina, Key Largo and Looe Key off Florida, the Channel Islands, the Farallon Islands and Cordell Bank off California, Gray's Reef off Georgia, and Fagatele Bay in American Samoa. Six are located in the territorial sea and two in the EEZ: the U.S.S. Monitor and Gray's Reef (Figure 3-10~. Scope of Development In light of recent advances in deep sea and exploration technologies, such as the ARGO/JASON program at Woods Hole Oceanographic Institution (Ryan, 1986), shipwrecks and historical objects
58 1 20°E ~' / / / I ~ ~ 60 ~° 50°W '`\\~S~ of r O ~ QO ~Baker Islands by ~ 10°S ~ o,S~' 6` \r \ \ W\ 1 20°E 1 50°E Midway Northern -~ / lowland Mariana Wake / Islands Island Johnston Island Palmyra Atoll/ Jarvis Island American Samoa \ ~ ~1 1 1 it\ :~0°N ~ A0° 1 ~1 0°S I I I I I \1 1 / 60° Puerto Rico/ \ 20° .Virgin Islands'\ 1 1 0 2000 Km `~ 1 , 1 \ 0 1000 N.M. 1 , 1 1 180° 1 50°W 120° 90° FIGURE 3-10 The seven U.S. National Marine Sanctuaries, and the U.S. EEZ. SOURCE: After Foster and Archer, 1988. will probably be discovered in increasing numbers. Some discoveries will be of considerable archaeological, cultural, and historical value. In the EEZ, establishment of marine sanctuaries has been used to designate and protect such sites (for example, the U.S.S. Monitor), but beyond national jurisdiction there is no legal framework for this purpose. In the case of H.M.S. Titanic, the Congress created a "memorial," but its restrictions are legally enforceable only against U.S. citizens. In the future, it is likely that professional and amateur treasure seekers will increase in numbers and interest in marine archaeology will also grow, but at a smaller rate. The availability of small submersibles in the coming decade or two will further stimulate treasure hunting. It is reasonable to predict that information demands will accompany the growth in these activities. With the continued popularity of snorkeling and scuba diving, more individuals will seek access to the seafloor in scenic underwater areas. The recent availability of relatively inexpensive submersibles for recreation could also create the need for more underwater destinations. Despite unrealized earlier predictions, underwater hotels are also likely to be constructed in a few especially interesting settings. Tourist submersibles are already operating; several vessels carrying over 40 passengers and crew are operating in U.S. nearshore waters (U.S. Virgin Islands, Guam, and Hawaii), but not yet in the U.S. EEZ. While these activities will create new demands for more detailed seafloor information in selected locations in the foreseeable future, these will fall within the territorial sea. With increased exploration of the EEZ, many new ocean areas deserving protection as marine sanctuaries will be identified. After formal national designation, management plans are formulated
so to protect the resource for which the sanctuary was created, yet allow other uses that do not impact the protected resource. Development Constraints Recreational and cultural ocean activities- especially treasure hunting, salvage, and marine archaeology_vill benefit from better information on the nature of the bottom load bearing characteristics and bottom topography; bottom stability, potential for sediment erosion, transport, and deposition; thickness of unconsolidated sediments; strength of bottom currents; and visibility. For marine sanctuaries, specific criteria need to be developed in advance that spell out the properties of various ocean areas deemed appropriate for sanctuary designation. Such early identification of candidate areas would ensure that legitimate sanctuaries are established before inconsistent competing activities are approved. The identification and designation process will require detailed site-specific information on physical and biological characteristics. Summary Increasing utilization of ocean-related cultural and recreational resources will stimulate demand for better and more detailed seafloor information. Because many marine areas contain rare and endangered species, uniquely valuable habitats, scenic coral resources, unusual geological formations, archaeological or cultural resources, or represent sites having exceptional research or recreational values, sanctuary designation is an important federal responsibility. Yet, to date, it has been a relatively low-level effort with only eight sanctuaries designated thus far. A waiting list for consideration now includes more than 30 candidate sites (Foster and Archer, 1988~.
