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4 TECHNOLOGY AND DATA ACQUISITION A large body of information is needed for planning efficient use and management of the EEZ seabed. Many data needs cut across individual uses. For example: oceanographic and meteorological data for real-time forecasts to improve operations and public safety; - data on sediment characteristics, including shear strength and permeability, compressibility, and geochemistry; information and knowledge of seafloor geologic processes, including landsliding, turbidity currents, faulting, erosion and scour, volcanism, and sediment transport and deposition; and information related to specific and multiple uses of the seafloor, including the need for improved environmental quality monitoring of seafloor uses and their effects. Obtaining this data in a marine environment frequently requires complex and expensive technologies and techniques specially designed for ocean use. This chapter presents assessments of the current status and future requirements of technologies and techniques used to gather information about the EEZ, including surveying and mapping technologies, geotechnical data collection activities, and environmental monitoring. A final section of this chapter discusses approaches to managing the large amounts of data that are likely to result from increased research and development efforts. In addition to present and emerging technologies and techniques, technical and nontechnical constraints that may limit technology development and deployment are examined. SURVEYING AND MAPPING There are four basic types of surveying and bottom mapping required to support development and protection of the EEZ seabed; these are water depth (bathymetric), seafloor imagery (mostly acoustic, some photographic), subbottom profiling, and direct sampling of seafloor surface and subsurface sediment characteristics. This section presents assessments of the current status and future requirements of seabed mapping and surveying technologies, including navigation technologies to correctly position seafloor mapping data. Included are a description of ongoing government, industry, and academic mapping programs; a discussion of mapping strategies; and an investigation of technical and nontechnical constraints that may limit technology development and optimal mapping programs. 60

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61 Background Surveying and mapping of seafloor characteristics provide fundamental and essential data and information for resource development and environmental protection. The seafloor can be mapped using a wide variety of tools and techninllP.c fit rliff~.re.nt `~l~c earl ~rr~lrari-` anA for Aif{-r=~t purposes. _ _ ~ ~7 ~A __^ _ ~ _, -~4 ~A.A ~AVA ~1115_] Aft L ^~;~nna~ssance surveys provide a oroac overview or regional geology, large-scale variations in seafloor morphology, rock or sediment type, and features resulting from long-term evolution of continental and island margins. Higher resolution mapping (with higher positioning accuracy) is required for task-specific or site-specific surveys. These are useful for precise resource assessment (Wpe, location, quality, and volume of seabed commodities); quantitative measurements of bottom conditions (sediment properties and geologic processes) for engineering design, construction, or installation of seafloor structures; and seafloor process mapping (movements of the seafloor and its overlying sediments) for environmental monitoring and research purposes. The state of knowledge and map coverage of EEZ regions on the continental shelf reflect the extent to which existing techniques have been applied in response to the needs of shallow-water users. However, most of the EEZ is beyond the continental shelf, in water deeper than 300 m, on the continental slope and rise. Use of these areas for resource extraction (particularly oil and gas) and activities such as telecommunications or military installations is increasing, and these areas are likely to become the principal location of development in the near future. This frontier region poses considerable challenges to survey methodology and practice. Although regional reconnaissance surveys are in progress, resource distribution and bottom conditions of the deepwater EEZ areas are generally poorly documented. Mapping Technologies Most seabed mapping is done by acoustic techniques, essentially by underwater remote sensing. Sound beams are bounced off the seafloor, or through the seafloor sediments, and their return time or return phase angle is measured. The resolution (fineness of detail) of different seabed mapping y~ ups use By Mu. - an'ge is lncreasea as sound frequency IS decreased. Lower frequencies, 3.5 kHz or lower, are required to penetrate sediments (subbottom profilers); medium frequencies, 12 kHz or higher, are required to avoid sediment penetration, thus accurately measuring the water depth (bathymetry) to the seafloor, or water/sediment boundary. In simple terms, the resolution of acoustic mapping data is generally increased by widening the frequency band width of the sound source, narrowing the width of the sound beams, reducing the width of the sound swath, reducing the survey ship speed, or reducing the system's altitude above the seafloor. The survey resolution is increased by reducing the distance between tracklines. or hv imnrovino the. ~rrilr-~-4r~1 of the navigation/positioning system. _ . ~--I ,~ ~ ~ ~- A ~ ~ ~ ~ ~ . 4 ~ _ __ ~ ~ ~ ~ ~y ~~ i ~~~^r~ ~ Seabed mapping technologies described below include bathymetric survey systems, side-scan sonar systems, swath imaging and bathymetric (combined) systems, subbottom profiling systems, and direct sampling technologies. Because accurate positions of all mapping data are necessary for the data to be useful, navigation/positioning systems are also discussed in this section. Capabilities of some commonly used acoustic mapping tools are described in more detail in McQuillin and Ardus, 1977; McClelland Engineers, 1982; Trabant, 1982; Kosalos, 1984; Prior and Doyle, 1984; Tyce, 1986; Davis et al., 1986; and Prior et al., 1988. Bathymet~y, the measure of ocean water depth, was the first bottom mapping technique to be developed. Originally, a lead weight was lowered on a line to give depths at individual locations. The development of sonar during World War I led to a new technique for measuring water depth. Single sonars mounted on a ship's hull measure travel time for sound to bounce off the seafloor and

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62 return to the ship. Depths are measured along a trackline directly under the ship, parallel tracklines are surveyed, and the area between tracks is interpolated and contoured into a low-resolution bathymetric map. Higher-resolution bathymetric data are derived from ~multibeam" or Swath bathymetry systems. An array of transducers on the ship's hull forms multiple acoustic beams, which completely ensonify a wide swath on either side of the ship (Figure 4-1~. Parallel tracklines provide 100 percent coverage of a survey area, so all areas between tracks are measured rather than interpolated. An additional increase in accuracy is provided because adjacent measurements within each swath are keyed to the same ship position. The first multibeam system was developed for the U.S. Navy in the mid 1960s. The first commercial multibeam (Sea Beam) was marketed in 1975; almost 20 are now operating worldwide. Bathymetric systems provide accurate water depth, and an accurate map of seafloor topography, but do not provide data on sediment type or thickness or show very small geologic features or objects on the bottom. Side-looking (or side-scan) sonars provide acoustic images of a swath of the seafloor, showing morphology (bottom topography), sediment type and distribution, and small geologic features showing geologic processes. Figure 4-1 shows comparative swath widths of some typical kinds of swath mapping systems. A low-resolution side-scan sonar currently being used for reconnaissance surveys of the U.S. EEZ is GLORIA (Geologic Longrange Inclined ASDIC), developed in the United Kingdom. GLORIA is towed near the ocean surface at 10 knots with a swath width of 60 km. There are many high-resolution side-scan sonar systems; operating characteristics of a number of them are shown in Table 4-1. These systems typically use a side-scan sonar frequency of 30 to 100 kHz, are deep-towed from 30 to 150 m above the seafloor (some "fly automatically at a certain height; others are controlled manually by cable length and tow speed), provide a swath of various widths up to 5 km, and are towed across the bottom at 2 knots. With an accuracy specification of 1 percent of water depth, SeaMARC II provides a high-resolution system for both bathymetry and imagery. Potential additional advantages are its ability to be towed below the water surface and moved from ship to ship. GLORIA SEAMARC ~ a. SWATH MAPPING SYSTEMS \\ "'"'a FIGURE 4-1 Comparative swath widths of some typical swath mapping systems. SOURCE: After Davis et al., 1986.

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64 Many deep-tow side-scan sonar systems also carry shallow-penetration subbottom profilers. These downward-looking sonars are typically 3.5 to 7 kHz in frequency and penetrate 20-to 100 m of sediment, depending upon sediment type. These profilers provide detailed geometry, stratigraphy, and structure in the upper sediment layers; they may show individual sediment beds as thin as < 1 m. Sound attenuation and beam spreading in deep water will degrade data from surface ship profilers. These different underwater remote-sensing tools employ various sensors to detect seabed characteristics, such as variations in acoustic reflectance and backscatter, gravity, and magnetic properties. The differences inherent in such methods are a consequence of relationships between range and resolution, which depend on the sensing system's properties. In common with other forms of remote sensing, ground-truth information (from bottom samples or cores) is essential for definitive interpretation of remotely acquired data. However, characteristics such as sediment texture, or "hard and "soft" bottoms, can also be inferred by correlating different types of remote data. Complementary sets of remotely acquired data from different systems conbined with direct sampling can lead to elegant three-dimensional perspectives of seafloor phenomena. In particular, sideways-looking (side-scan) sonar provides images of seafloor morphology, sediment distribution, and signatures of geologic processes. Subbottom seismic profilers at various frequencies- give near- surface sediment geometries, stratigraphy, and structure. Data from these systems is combined with bathymetry and in situ ground-truth data. Table 4-1 reviews the principal bathymetric and seafloor . . Imaging sonar systems. This area of technology development is dynamic; experimental new systems and advances in existing ones occur with regularity. The following review is not exhaustive, but presents state-of-the- art technology. Sea Beam: This multibeam bathymetry system uses sensors in the hull of the survey vessel and has depth resolution of 1 m and accuracy between 10 m and 50 m in deep water (Circe, 1986~. Swath widths are 0.8 times the water depth over a depth range of 100 to- 11,000 m. SeaMARC II and Sea Beam bathymetry for the same area are depicted in Figure 4-2. GLORL4: This sideways-looking sonar is towed close to the survey vessel at a speed of 10 knots and has a 60-km swath. For most EEZ water depths, the actual range is 10 times the depth. The seafloor imagery has a pixel size of 50 m. The GLORIA II system is capable of rapid, large- area, regional coverage of large-scale features (Figure 4-3~. Argo/Klein and SIR: Argo is a deeply towed camera system that incorporates a side-scan sonar for high-resolution bottom images (similar to Edo 4075) over a 200-m swath at 1 knot (Tyce, 1986~. SAR is a high-frequency, high-resolution, side-scan sonar that can obtain 1.5-km swath widths at 2 knots, but has seen only limited operational application. SeaMARC I: This is a deeply towed imaging system for site-specific surveys with both side- scan (27/30 kHz) and subbottom profiler (4.5 kHz). Transmitters and sensors are contained in a ~fish" deployed 100 to 700 m above the seafloor at 2 knots. Swath widths are 1 to 5 km, and image pixels are typically 1 x 5 m, with cross-track resolution of 0.5 to 2.5 m (Davis et al., 1986~. SeaMARC I can simultaneously record seafloor features and subbottom sediment geometries. Edo 4075: This is a sideways-looking, deeply towed sonar system incorporating a 3.5- to 7.0-kHz subbottom profiler. The towfish automatically traverses bottom irregularities with the positively buoyant vehicle held at a constant altitude of 30 to 50 m above the seafloor by a ballast weight. Range is 200 to 400 m at 2 knots. Its high-quality images of seafloor and subbottom topography, sediment texture, and geometry are suitable for site-specific engineering (Prior and Doyle, 1984; Prior et al., 1988~. GLORIA II, SeaMARC I, and Edo 4075 data for the same area are compared in Figures 4-4, 4-5, and 4-6. Although the Edo 4075 swath widths are narrow (maximum 800 m), this system provides superior resolution. Scripps Deep Tow: A side-scan suIvey system capable of a wide variety of geologic, oceanographic, and biologic missions, this system has a typical swath width of 1.5 km, tow altitude of 150 m, and speed of 2 knots. .

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65 FIGURE 4-2 SeaMARC II bathymetry (50-m contour intervals and Sea Beam bathymetry (20-m contour interval) for the same area are compared. SOURCE: Davis et al., 1986. EG&G 990: This is a high-resolution, deeply towed, 1-km swath system with cross-track resolution of 1.3 m and alongtrack of 2 m, at 100 m above the seafloor. Maximum operational depth is 6 km; tow speed is 2 knots. Operational effectiveness in deepwater high-relief areas is reduced by the need to tow the sensor close to the seafloor, with towf~sh altitude controlled only by cable length and ship's speed. SeaMARC II: This sideways-looking sonar is towed close to a survey vessel and simultaneously records seafloor imagery and swath bathymetry (Figure 4-3~. It is capable of ranges of 1 to 10 km at tow speeds of ~ to 10 knots. Its imagery is composed of 1,024 equidimensional pixels over a range of 5 km per side, with a horizontal resolution of about 5 m. The swath bathymetry has a depth resolution of 20 to 50 m. SeaMARC II is capable of large-area regional surveys with higher spatial resolution and sensitivity to bottom roughness than the GLORLA system (Davis et al., 1986~; however, relative to GLORIA, it has a significantly reduced swath width. Profiling Systems Profiling systems used to acquire information on water depth, seafloor profiles, and subsurface sediment, geometry and stratigraphy are listed in Table 4-2.

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FIGURE 4-3 GLORLA imagery and SeaMARC II imagery for the same area. The images have reversed polarity (the SeaMARC II image shows steeper areas as dark, the GLORIA image shows them as light). Tracklines in the SeaMARC II imagery are approximately 10 km apart. Water-Depth Echosounders: For deepwater surveys, narrow-beam systems are required to minimize off-line echoes, and calibration for actual water column velocity variations is necessary to determine absolute depth (e.g., Prior et al., 1988~. Subbottom Profilers: Profiling systems operating between 3.5 and 7.0 kHz can penetrate up to 30 to 50 m in soft sediments. However, penetration and resolution depend on geologic conditions and are highly variable. They are usually much less in sandy, cemented, or gassy sediments. Resolution of individual beds and strata may be less than 1 m. In deep water, beam spreading and attenuation from surface sensors reduce penetration and resolution. Figure 4-7 compares a surface-towed, 3.5-kHz profile with data from a deeply towed system 30 m above the seafloor (Prior et al., 1988~. Medium-Penetration Profilers: Various medium-penetration, medium-resolution systems are used to provide details of sediment stratigraphy to 900 to 1,000 m below the seafloor (e.g., Minisparker, water gun, or minisleeve exploder). Actual penetration and resolution are affected by geologic conditions and the type, frequency, and power of the sound source. Data recording may be

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67 ~ L 1- ) ~ l . GLORIA . _ . .. - ~ __1 _~; FIGURE 4-4 GLORIA imagery of part of the Gulf of Mexico. The same channel feature is further illustrated in Figures 4-3 and 4-6. single- or multichannel; the latter allows post-cruise processing to enhance usefulness of the profile data. Figure 4-8 illustrates information acquired by both 3.5-kHz subbottom profiling and multichannel data for the same area. Because of the apparent differences in penetration and resolution of the two types of data, both types of data are usually acquired simultaneously. Interpretation of near-surface geologic conditions is based on both 3.5-kHz and medium-penetration profiles. Direct Sampling Seabed sediments and rocks can be retrieved using sediment grabs and dredges for surface materials, and boring, coring, probing, or drilling for subsurface samples. Characteristics of the retrieved materials and data from in situ measurements can then be mapped. Spatial integrity of the maps is directly related to sampling density, because of seafloor and subsurface variability between sampling sites. Sediment types, mineral deposits, and geotechnical properties inferred through other types of survey data are typically confirmed using direct sampling. Complementary sets of remotely

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.. ..: ~ ::::::::::: :::::::::: ::::::::: ::::::: ::::: ::::::::: :::::: ::::::::: ::::::: ::::::::::: :::::::::::::::::::::::::::::: ::::::::::::::::::: SEAMAR I 5~ SW=H ............... ,,,.,. , , ,~., ~,. ..... ... .... ....... ......... ... ..... ..... ......................... ... KHZ FIGURE 4-5 SeaMARC I imagery of the same channel showed by GLORIA data in Figure 4-2. Contrasting scales and resolutions (5-km swath, 1-km swath) are given. The 4.5-kHz subbottom profile accompanies the 1-km swath. SOURCE: Kastens and Shor, 1985. acquired data from different systems combined with direct sampling can lead to elegant three- dimensional perspectives of seafloor phenomena. Navigation/Positioning Systems The principal linkage between all survey and sampling measurements is navigation or position accuracy of the data collected. Historically, the accuracy of navigation systems has lagged the accuracy of survey and sampling systems, which has served as motivation for development of better navigation capabilities. Navigation systems can be characterized by the location of the reference systems: land-based systems, ship-based systems, seafloor-based systems, and satellite-based systems. Land-based navigation systems have long been standard for survey operations conducted within range of shore stations. The permanent coastal navigation system, Loran C, has excellent repeatibility (return to same spot, but not necessarily know where it is) of 15 m, and sufficient range (300 nm) for EEZ surveys, but has insufficient accuracy (0.25 nm) to support many survey needs. A

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3~5 KHZ .. UPPER Fll - EDO 4075 400M FIGURE 4-6 Edo 4075 imagery (3.5-kHz subbottom profile and 100-kHz side scan) for a portion of the channel shown in Figures 4-4 and 4-5. SOURCE: Prior et al., 1988. global land-based system, OMEGA, has been used to support open-ocean navigation, but has insufficient accuracy (1 to 4 nm) to support most EEZ surveys. Differential OMEGA (setting up a well-located, shore-based reference/retransmitting station) can reduce errors to 0.5 rim at 200-nm range, still insufficient for many survey purposes. For accurate nearshore surveys, temporary installations are generally used. These employ user-passive hyperbolic radio transmission systems (Argo, Sylidis), or user-active radar transponder ranging systems (Falcon, Miniranger, Hi-FL~). These systems have accuracies on the order of 1 m, but require careful surveying of the base station locations, and have ranges of only 50 to 100 nm. Ship-based systems generally determine range and bearing to stationary acoustic beacons, benchmarks or structures on the seafloor, or aboard moving vehicles. Ship position is the reference point from which all other positions are measured. These systems are called "short baseline" if they use the time of arrival of the beacon's signal at sensors widely spaced over the ship's hull for positioning. They are called "ultra-short baseline" if they use the phase difference of the beacon's signal at a closely spaced array of sensors. The accuracy -of these systems is a function of both the accuracy of the underwater acoustic transmission and reception, and of the ship's position determined through other means. Seafloor-based navigation systems generally consist of acoustic transponders, either on the seafloor or tethered some distance above. While limited in range by acoustic propagation to tens of kilometers, triangulation in range from bottom transponders produces navigation accuracy ranging from 1 m for near-bottom receivers to 50 m for surface receivers (such as ships). Systems are being

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87 Centrifuge model testing is a developing technology with universal application to seabed engineering problems. Acceleration applied to physical models can be used to induce conditions that accelerate various processes and simulate natural events. Centrifuge testing has been conducted to solve many offshore problems involving quasistatic cyclic loading conditions (Rowe et al., 1976; Craig and Al-Saoudi, 1981; Rowe, 1983~. The theoretical principles of operation of the centrifuge have been described by Schofield (1980~. This equipment provides the capability to test platform models with diameters up to 100 m, piles with diameters of 2 m, and caissons with diameters up to 12 m. Its key benefit is the economy for experimentally checking models described by complicated analytical procedures. Increased use of centrifuge modeling is expected to enhance the understanding of the mechanism of foundation behavior and to provide direct design parameters for performance predictions. Technology Limitations/Needs The technology for acquiring samples, performing laboratory tests, and obtaining in situ and experimental geotechnical data is technically mature for water depths to 300 m within the continental shelf areas (see Zuidberg et al., 1986; Briand and Meyer, 1983~. Development activities in the Arctic and off the continental shelf in depths exceeding 300 m will depend not only on advances in technology but on the availability of research vessels. For example, a dynamically positioned drill ship is necessary to acquire geoscience data in water depths greater than 300 m when seafloor penetrations greater than 10 m are required. However, there are only two of these specialized vessels capable of working in these extreme water depths, and both are foreign-flagged and stationed in the North Sea. Use of these vessels in U.S. EEZ waters will require costly mobilization, which restricts their use except for the most extensive developments, such as site investigations for oil and gas production facilities. The drill ships operated under the Deep Sea Drilling Program (DSDP) and the Ocean Drilling Program (ODP) operate under international scientific agreements and are not available for use for national resource assessment purposes. The restricted availability of these vessels has limited major research programs to quantifying near- seafloor characteristics. The limited availability and high cost of geotechnical research drill ships could be mitigated by development of a rapidly transportable seafloor deployment system (Figure 4-133 that could be operated from a surface vessel, an ROV, a manned submersible, or a submarine (Young et al., 1988b). The system needs to be compact, possess onboard memory, and be capable of thrusting geotechnical probes and samplers to relatively deep penetrations (as much as 100 m) below the seafloor. If operated from an ROV, it should be capable of being deployed from a small supply or oceanographic vessel without fixed mooring. The various development applications within the EEZ may impose exceptional requirements on the capabilities of the device as presented in Table 4-8. In situ probes and sensors have been developed and used extensively over the past decade to acquire geotechnical data. In situ and laboratory test results have been used successfully in water depths to 300 m; however, stress relief and soil degassing will intensify in samples obtained from deeper water, which will complicate data interpretation. Additional improvements in in situ data interpretation will be needed to confirm the reasonableness of the data for design purposes. The capability to measure true, in situ ambient pore pressure to determine the existence of hydraulic gradients in various geological environments will also require special attention in the future, because knowledge of in situ ambient pore pressures will provide a better understanding of altered pore pressures induced in samples obtained from extreme water depths (Denk et al., 1981~. Samplers and in situ testing probes and sensors feature a number of different designs, and standardization of test procedures will be needed in the future. For example, the location of measurement sensors and test speed are known to influence pore pressure measurements, which could complicate data interpretation for design purposes.

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88 Handling / Frame ~ Hoisting / // System Electromechanical Umbilical ~ ; 1 Tethered Seafloor Plafform Geotechnical Probe FIGURE 4-13 Rapidly transportable deployment systems. SOURCE: Young et aL, 1988b TABLE 4-8 Exceptional Testing Requirements for Various EEZ Development Applications Development application Exceptional requirements Oil and gas Waste disposal Military Piplines and cables Minerals and mining Large penetrations beneath seabed Wide variety of tests Site variability definition Chemical and thermal characteristics Permeability and absorbent characteristics Rapid deployment Acoustic characteristics Bottom signatures Rapid, route deployments Thermal characteristics (Arctic) Rapid, area, region deployments Consideration, concentration, chemical characteristics

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89 Summary The capability to acquire geotechnical data by sampling and by in situ, laboratory, and experimental testing has improved greatly over the past decade, and this technology is relatively highly developed for shallow-water areas (less than 300 m). Advancing to deeper water and the Arctic will depend on further development of improved sampling and in situ testing equipment capable of determining sediment properties in difficult offshore environments. It will also require improved experimental testing methods capable of measuring seabed properties and behavior in a more controlled manner. Compact deployment systems are needed that can operate rapidly and automatically to measure engineering properties or sample seabed sediments. As activities expand into EEZ frontier areas, new geologic models will be required to characterize sediment properties and behavior in engineering terms. New interaction problems between sediments and foundation elements arising from innovative structures, such as tension leg platforms, will require development and verification of analytical models and field monitoring of the structures. New and improved data acquisition systems will allow accurate and meaningful data to be collected that better describe engineering properties and geologic conditions that could strongly influence the design, location, construction, operation, and maintenance of engineering projects planned for the EEZ. However, their development will require a thorough technical evaluation. Future proposals for technology development by government and industry must consider priorities and objectives for various data acquisition systems because of their complexity, cost, and time frames. EEZ SEABED MONITORING The seabed of the U.S. EEZ is almost as varied as the seabed of the entire ocean, and the environmental consequences of expanded activities in this region will be difficult to predict in advance. Environmental monitoring provides a basis on which such predictions can be made, but past EEZ monitoring has had mixed results. During the 1970s, $27 million was spent on background studies for environmental impact statements for OCS oil and gas (MMS, 1973-79~. However, the biological data were collected over such a large area that the impact of subsequent operations on local organisms and environments was difficult to assess. A more focused and useful effort conducted on Georges Bank in the late 1970s occupied monitoring stations at various distances from drilling vessels during all drilling phases. The effects of drilling muds on sediments were well documented, biological impacts were easier to ascertain, and the observed changes provided criteria for modifying discharge requirements in future drilling operations (NRC, 1978~. Several possibilities for structuring an EEZ monitoring program have been suggested (Segar, 19~) monitor to verify or refine models of the transport, fate, and impact of materials; monitor to determine if the response of specific indicator organisms to pollutant levels is sufficient to trigger remedial action; establish background levels of critical substances prior to using a particular area and then monitor to evaluate temporal and spatial changes (trend assessment monitoring); and monitor to assess compliance with water or sediment quality regulations and environmental use-permit requirements (compliance monitoring). Based on these past efforts and evaluations, this report will focus on three types of monitoring. 1. Reference monitoring establishes transects or sites that can be occupied for years, collecting measurements that yield general baseline reference data for time-series considerations. These data

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go may or may not be linked to a specific process or activity and will aim to provide critical insights about the variability of the seabed environment. 2. Process-onented monitoring is conducted where important near-bottom processes can be easily studied to understand and predict their interaction with EEZ uses. 3. Use-related monitoring is the measuring of parameters to assist a proposed or ongoing seabed use and evaluate its impact. Reference Monitoring Interpreting information gathered during EEZ surveys or studies of basic processes often suffers from insufficient knowledge of the long-term environmental context. Natural temporal and spatial variations in physical, chemical, and biological properties must be understood in order to realistically interpret any observed changes. Proper design of use-related monitoring programs requires such long-term knowledge. One approach to reference monitoring is to designate specific long-term benthic reference sites or transects in the EEZ. How many of them should be designated, how they should be selected, and where they should be located will depend on their purpose and on available personnel and resources. It is not physically or fiscally possible to continually monitor large areas or an extremely large number of smaller areas. Criteria and considerations necessary for selecting specific reference sites are examined in depth in the report of a National Academy of Sciences panel (NRC, 1984~. Because the U.S. EEZ is so vast and monitoring time-scales can range from minutes to decades, selecting reference locations may depend on considerations such as those that follow. . Me number of locations needs to be large enough to cover several characteristic types of seabed environment and small enough to permit the intense sampling required to detect higher frequency events. Locations could be similar in concept to the Long-Term Ecological Reference (LTER) sites on land (Callahan, 1984~. They could be placed either in typical seabed regions to optimize their basic research value or in areas where future seabed uses are anticipated to permit acquisition of truly long-term baseline information. Reference locations may also be selected in areas designated as preservation areas. Achieving a consensus on selection criteria will require considerable input from the scientific community, environmental groups, and potential seabed users, and will depend on the projected resources for long-term sampling and monitoring. Sampling strategies at the reference sites may follow two major phases: 1. initial high-frequency sampling to establish the characteristic scales of temporal and spatial variations, and 2. long-term sampling programmed to maximize information return and performed at optimal frequencies based on phase 1 results. Protocols for seabed and near-bottom reference sampling will depend on the phenomena being studied and the terrain. Complex seabed terrain with large relief will a Anon be a candidate for higher density sampling than low-relief seabed or gradually changing water depths. Basic measurements include water transport (currents, turbulence), water properties (salinity, temperature, suspended particle concentrations, nutrients, and dissolved oxygen, etc.), biological diversity and abundance, and sediment properties. Utilizing the latest monitoring technologies will increase cost effectiveness: for example, measurement of current patterns by acoustic tomography (Munk and Worcester, 1988) and measurement of sediment credibility by instrumented flumes. Although very little reference-site monitoring is being done now, the next ten years should see increased activity.

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91 By then, appropriate techniques should have been perfected to such a degree that reference monitoring could remain at a steady level into the future. An aspect of reference monitoring that may indicate pollutant levels near the seabed and provide early warnings of environmental degradation uses "sentinels organisms along with measurements of sediments. Such early warnings can be followed by detailed specific investigations. The sentinel approach is analogous to NOAA's National Status and Trends (NS&T) Program in coastal and estuarine environments (NOAA, 1984~. (NS&T also includes a specimen bank so substances that may be designated pollutants in the future may be evaluated in previous environments.) An ~EEZ-NS&~ program would not necessarily be linked to a specific seabed use or to reference-site monitoring. Because of EEZ water depths and seafloor environment diversity, choosing sentinel organisms and sediment analysis methods might be more difficult than in the NS&T program. If a consensus could be reached, however, an EEZ NS&T program could be pursued for 10 or even 25 years, with organisms and pollutants updated as necessary. Process-Oriented Monitoring The objective of process-oriented monitoring is to acquire detailed knowledge of natural processes that have intense effects on specific seafloor areas and that cannot be adequately studied with reference monitoring. The two monitoring approaches may overlap to some degree if important processes happen to occur in reference areas. As interest in various processes wanes or waxes, some process-oriented monitoring sites will be abandoned and new ones chosen, thus making process-oriented monitoring inherently shorter-term than reference monitoring. Typical processes that have been studied include the following. . Shifts in major ocean currents that impinge on the bottom, such as those examined in the mid-Atlantic region (Lee et al., 1981, 1982~. Their study focused on physical and chemical changes associated with the Gulf Stream moving onto the U.S. continental shelf, but did not include consequences to benthic organisms. Grounding of sea ice and its impact on sediment properties and seabed communities off Alaska has been investigated by the Navy and by oil and gas industries (AO GA, 1978), but techniques for observing it directly are not well developed, and many questions remain (NRC, 1985~. Mass wasting of sediment near the shelf break, at the head of submarine canyons, or in other EEZ areas has been studied for many years (see Chapters 2 and 3) and very likely will be continued and expanded. Parameters to be measured and monitoring frequency (from minutes to years) and duration will vary by process and proposed use. Important parameters include temperature, salinity, geotechnical properties, near-bottom turbidity, dissolved substances (nutrients, oxygen, and trace metals), current speeds and directions, and pollutants in both the seabed and the adjacent water column. The need for process-oriented monitoring will increase in the next 25 years as EEZ uses increase. Two uses of the seafloor near the shelf break expected to expand in the next 10 years-oil and gas production and undersea submarine surveillance will require better ways to predict physical and chemical consequences of shelf-break erosion or sediment loss. The effects of these processes will need to be studied well in advance of installation of bottom-tethered equipment because of the large variety of potential sites and length of time over which predictions must be made. Use-Related Monitoring Use-related monitoring ensures that seabed installations function properly and determines whether remedial action is necessary if a particular EEZ use (waste disposal or mineral exploration,

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92 for example) poses hazards to human health, living marine resources, or overall quality of the marine environment. Monitoring for use-related impact is the most common form of monitoring conducted today, particularly trend assessment and compliance monitoring. Waste Disposal A conceptual model setting the framework for waste-related environmental impact monitoring and its associated decision-making process proposed by an NRC panel on particulate wastes (NRC, 1989) focuses on how and over what time scales organism-sediment interactions may be affected by changes in particulate material composition or character on the seabed, and on the feedback of monitoring data to modify a permitted dumping protocol (Figure 4-14~. To restrict scattering, particulate wastes dumped at sea are typically placed in long-term repositories in areas thought to be quiescent. To confirm the suitability of potential waste sites, a monitoring program normally includes short- (days) and long-term (seasons to years) measurements of water flow and circulation. In the initial stages of dumping, short-term baseline monitoring of the water and the physical and biological characteristics of the sediments around dumpsites may be advisable. A technique that may prove useful is the technology of remotely sensing the seafloor using optical data on the upper sediment. Its appeal is the ability to survey large areas (i.e., square kilometers) of the seabed in only a few days (Rhoads and Germano, 1986~. Remote sensing technology is particularly effective for evaluating the depth to which dissolved oxygen penetrates the sediment, which is critical to the mobility of both contaminants and benthic organisms. Because of speed and low cost, some improved version of this technology will probably be employed to survey areas around dumpsites and PARTICUlATE WASTES I Dumping Protocol 6' CHANGE , . . 1 ! 1 LOSS TO WATER COLUMN LONG-TERM QUIESCENT REPOSITORY 1 1 1 Benthic Processes a. Physical -- currents, tides, turbulence, etc. b. Biological -- bioturbation, respiration colonization, population development, etc. FINAL CONDITION a. Contaminants dispersed or sequestered? b. Benthic populations healthy or unhealthy? Physical Monitoring Quick Bio-monitoring (e.g., REMOTS) Chemical Monitoring (Sediments, indicator species, etc) Long-term Population Monitoring (REMOTS, BRAT, histopathology, benthic species distribution and chemical composition) FIGURE 4-14 A monitoring decision model for waste dumping in the EEZ. . 'Short-term Monitoring - ~ TECHNICAL DECISION MATRIX r

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93 determine which ones need more detailed, longer-term studies. Remote sensing technology is limited to providing a quick scan of a vertical section and does not produce information about complex benthic interrelationships. Long-term monitoring (Figure 4-14) will also involve a more complete benthic evolution of sediment and fish or benthic animals living in (infauna) or on (epifauna) the sediments at sites likely to be affected by dumping (Rhoads and Germano, 1986~. This longer-term monitoring will also include histopathologic studies of collected organs and tissues of animals, which are the easiest and most effective way to assess their physiological condition or "healths (Yevich and Barszc, 1983~. The single most important consequence of waste-disposal monitoring should be a rapid response to detected changes. Dumpsite monitoring data fed into a Technical Decision Matrix at several stages of dumping (Figure 4-14) can indicate unacceptable environmental departures from previously established limits. In such a situation, a speedy regulatory decision to modify the dumping protocol will minimize damage to the biological community at the site. Some projections can be made about waste disposal monitoring over the next ten years. For dredged material disposal, the Army Corps of Engineers has designed a project using a more elaborate version of Figure 4-14 to anticipate the impact of dredged material deposited in New England coastal waters (NRC, 1989; Fredette et al., 1986~. A similar approach may be increasingly employed to follow and manage dredged material dumping in the EEZ, and could also be applied to fly ash and incineration ashes. However, greater water depth and more varied terrain will require modification of the monitoring decision protocol. For example, wastes dumped into deeper waters will be more dispersed and diluted than in shallow water, so more sensitive surveying and sedimentary analysis techniques will be required. This problem was highlighted by the difficulty of finding dumping residues at deepwater dumpsite 106 off the east coast (O'Connor et al., 1983~. Further, management decisions may have to be made on the basis of fewer samples, because of the difficulty and greater costs of deepwater sampling. Over the next ten years disposal of ~packaged" wastes (i.e., ash and sludge blocks or containerized nuclear wastes) is anticipated (Manheim and Vine, 1987~. Packaging of incineration ash and hazardous waste in stabilized blocks may require special monitoring strategies that will differ from those discussed above because interactions between the benthos and the package itself will have to be considered (Roethel et al., 1986; Shieh et al., 1989; Manheim and Vine, 1987~. These interactions will be important to predicting package lifetimes and waste release rates. Packages may attract or repel species, thus different indicator organisms may be needed and sampling strategies may require sampling near the packages without disturbing them. Oil and Gas Monitoring associated with oil and gas exploration and production has two purposes: to guarantee stability of pipelines and platforms, and to ascertain and minimize environmental damage during drilling and production. Stability assurance requires pre-use, site-specific information on subsea and seafloor charcteristics, and historical data on winds, waves, and currents. Process monitoring will determine the magnitude and velocity of the seafloor sediment movement and seismic surveys of active surface faults (e.g., the Santa Barbara Channel), will estimate potential effects of fault motion on structures, and will determine if fault motion is influenced by production operations. Exploration and drilling in the deeper water and the arctic EEZ will probably increase most rapidly over the short term (ten years). In deeper waters, monitoring will have to be modified to cope with the rigors of greater depths. This may result in reliance on remotely operated vehicles and sampling systems. In the Arctic, ice floe movements, seasonal ice presence, and marine animal migration and life cycle patterns need to be predicted both regionally and at specific exploration and production sites. Tracking ice by satellites using microwave radiation in synthetic aperture radar

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94 (SAR) may become important because of SAR's ability to penetrate cloud cover. SAR's large power requirements are a problem that will have to be overcome, however. It should be noted that there is no procedure presently set up to follow the long-term effects-of a large oil spill that happens to reach the EEZ seabed. Minerals Monitoring needs of EEZ seabed mining are difficult to forecast. If sand and gravel mining in waters increases and moves to deeper deposits, pre-use and use-related monitoring would be indicated (U.S. Bureau of Mines, 1987~. For any mining activity, impacts on benthic communities at the mine site and surrounding areas large enough to evaluate far-field effects that need to be assessed include recolonization rates, metabolic energy fluxes, sensitivity to sedimentation, and other ecosystem relationships. Mining of iron-manganese crusts could cause serious environmental impacts, but few studies of undersea mining impacts on surrounding environments have been done (Manheim, 1986~. Research for environmental impact analysis (fates and effects of suspended sediments in surface water and composition and dynamics of benthic ecosystems, for example) needs to keep pace with the schedule of commercial development. Military Use-related monitoring of military activities in the EEZ seabed occupies a curious position because so much data is and probably will remain classified. Weather-related data are not generally available to other EEZ users, and other data (e.g., from the Fleet Numerical Weather Facility) may have only limited availability due to the Navy's need to keep sampling locations secret. Naval test ranges are used thoughout the EEZ, but it is not clear if there will be environmental investigations related to this use. Recent changes in policy have opened up much of the bathymetry to the public domain. The accessibility of Navy monitoring data of disposed equipment is better. For example, as part of the CHASE (Cut Holes And Sink 'Em) scuttling operations, environmental evaluations were performed to assess impacts, and the data are generally available. Navy monitoring of disposal of surplus or outdated equipment and supplies will probably continue over the next 25 years, and data will likely be available. Monitoring Needs Pollutant Detection Detecting sewage sludge in sediments at deepwater dumpsites (such as Site 106 off the New York Bight), may be extremely difficult because the presence of existing nonsludge sediment and the feeding and movement of seabed organisms lower the sludge content of the sediments (O'Connor et al., 1983~. The sediment analysis may not accurately reflect the extent of the environmental damage. Also, the coarse-grained sediments in the shelf-edge portions of the EEZ are more difficult to analyze than the finer-grained coastal and estuarine sediments analyzed under NOAA's NS&T program, since pollutants are primarily associated with clays. In these situations sediment traps might be used to collect sinking particles and estimate the rain of pollutants to the seabed. There are problems with sediment traps (e.g., the hydrodynamics of particles), however, and research on trapping techniques is still required (NRC, 1984~. Which pollutants should be measured in EEZ monitoring has not been addressed either. The organic and trace-metal pollutants monitored under the NS&T program (NOAA, 1984) might be

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9s adopted for the entire seabed region of the EEZ, with some adjustments made for substances to be measured and tissues to be analyzed. Biological Assessments Choosing sentinel or indicator organisms may be more difficult in the EEZ than in coastal waters. Benthic life in the EEZ differs from that of coastal waters. For example, increasing depth works against the presence of large multicellular plants (macroalgae) on the seabed because overlying water absorbs too much light. Also, assessing species populations over the larger areas and great variety of benthic environments in the EEZ will be a lengthy process using conventional techniques, such as taking core or sediment samples, sorting animals into size fractions with sieves, and identifying and determining their condition. This work is expensive and takes days to weeks to do for a single site. A well-conceived monitoring program will have to consider many sites spread over a large area, some of which will be reoccupied continuously. Demand for data will require continued development of remote sensors of physical, biological, and chemical conditions on the EEZ seabed. Sampling Strategies Determining sampling frequencies and technologies to define a given phenomenon are difficult because time and space capabilities of sampling devices or platforms have to be matched to the domain of the phenomenon being studied (Figure 4-15~. For example, a single ship cannot determine synoptic spatial distribution of phenomena that recur every few days because it cannot return to a given location in an area that may cover hundreds or thousands of square kilometers. Sampling frequency is also affected by costs, since the magnitude of sampling needed may be financially prohibitive even though the technology exists to do it. Reaching compromises between optimum sampling schemes, available technologies, and funding resources will probably be among the thorniest issues to be faced by EEZ monitoring programs. lo7 oh ~ 1 o6 Al O. A Al 104 - C' 1 03 of: ~2 to 10 1o1 - (a) Be r ~ 1 ~ 1 10 2 1o~1 1 10 102 103 TIME DAYS n ZOOPLANKTON - (b) I 1 1 1 1 AIRCRAFT ~1 1 1 1 1 1 ~1 BALOONS / SATELLITES WHIPS ~ 1 ~ ~ ~ , / I I Be 1 ~11 ~ 1 -2 10 1 1 10 1o2 103 TIME DAYS Figure 4-15 (a) Time and space domains of circulation events, habitat variance, and biological abundance in relation to (b) duration and scale of sampling platforms. SOURCE: After Walsh, 1988.

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96 Frontier Environment Considerations Monitoring instrumentation needs for the EEZ are those needed to adapt to deeper water and arctic environments. Instruments left for longer exposure times (due to sampling frequency requirements or longer distances) and in deeper water may face problems of fouling, stability, and calibration of physical and chemical sensors. In the Arctic, technology improvements are needed to follow ice movements and study ice gouging in detail (NRC, 1985~. SAR power and data storage requirements of synthetic aperture radar are too great, and the minimum sizes of ice floes detectable by other remote techniques are too large. Technology Advances include Advances in measurement technologies that will improve monitoring over the coming years acoustic tomography to obtain large-scale pictures of water-mass movements in short time periods (Munk and Worcester, 1988), lasers to study movement of suspended particles (Carder et al., 1982), instrument packages with oxygen microelectrodes to investigate sediment chemistry on millimeter scales (Revsbeck et al., 1986), and rapid acquisition of data from monitoring buoys using satellites. Nontechnical Problem Resolution The principal nontechnical constraints to EEZ monitoring are monitoring priorities, designation of monitoring organizations, determination of monitoring frequency and duration, quality control, protocol for monitoring data release, and adequate funding. Information sharing among EEZ seabed users will be a problem because there is no central repository for monitoring data that can provide timely access for users (see "Data Managements for a more complete discussion). Given the many and varied U.S. monitoring efforts, a single project will probably not obtain all the data that will ultimately be needed. Especially important are data taken simultaneously from many locations, which are vital to devising computer models that can predict actual events as closely as possible to real time frames. Delays in data delivery will make short-term predicting (hours to days) after a monitored event extremely difficult. Another data-sharing problem is the classified or proprietary nature of Department of Defense (DOD) and industry monitoring data. For example, DOD may choose to classify bathymetry data in areas that are also important for such uses as deciphering the shape of terrain around waste-disposal sites. Mechanisms to speed review and release of such data would be useful. Summary Monitoring will provide vital data on natural variability and baseline information about benthic processes that affect areas of proposed or ongoing EEZ use. Linking use monitoring data to regulatory decisions will allow rapid response to hazardous situations. The magnitude of the EEZ area, variety of benthic environments, and greater depths will affect what is selected for monitoring, how much it will cost, how long it will take, and what kind of technology is needed. Accomplishing EEZ monitoring will require planning and commitment of resources adequate to the task. Without them, data quality and quantity could be inadequate for making sound decisions regarding permitted uses, perhaps ultimately leading to inadvertent and unacceptable environmental damage.

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97 DATA MANAGEMENT As development of the EEZ progresses, enormous amounts of data will be collected by government agencies, industry, and academia using the technologies described in this chapter. Already very large data sets exist or are being developed, including bathymetry, seafloor imagery, subsurface seismic profiles, bottom samples, and cores, together with oceanographic and biological data for the seafloor and benthic boundary layer. These data are widely dispersed and exist in different formats and archiving styles, a situation that lends itself to a distributed network rather than a centralized system. Much of the data gathered by government agencies are archived at NOAA's National Geophysical Data Center and are publicly available. By comparison, seismic data, particularly multichannel exploration profiles, are collected by industrial groups and are proprietary. Various projects, including CONMAP (USGS) and the Strategic Assessment Atlas Project are compiling inventories of EEZ data. Industry consortia projects frequently combine and phase data for mutually agreed tasks for particular EEZ areas, but there are no shared data inventories. Management objectives for rapidly expanding the EEZ data base are the efficient use of available data and the reduction of unnecessary duplication by facilitating data accessibility and exchange. While EEZ data sets are large and will expand dramatically in the future, data management hardware is not a problem. The computer industry is aggressively competing to develop more capable components and systems for data handling, manipulation, transmission, and storage. Nonhardware problems do exist, however, including appropriate management systems and diversity in hardware, software, networks, and user operation conditions. Various data management options need to be examined within an actual, defined framework of what data exists, what will be acquired, and how available they are. Compiling a basic inventory of industry, government, and academia data collections, formats, styles, quality, and availability is the logical next step. Geographical information systems (GIS) are effective data storage and retrieval tools in which geographic location and areal distributions are important attributes. An EEZ GIS could combine data on water depth, bottom gradients and roughness, sediment types and thicknesses, seafloor biology, and bottom processes with precise locations of sample sites, monitoring sites, boreholes, and survey lines. Additional data would include past, present, and anticipated manmade features, such as wrecks, dumpsites, cables, pipelines, abandoned wells, and bottom structures. Data that might be contributed to an EEZ management system come in a variety of forms, so any system will face the special challenges of not only locating and cataloging data, but describing specific formats and providing instruction as well. Thus establishing standard formats and guidelines for directories, catalogs, and networks is an essential preliminary task for achieving effective data management. Another important problem is the diversity of existing computer facilities and networks. Since this situation is unlikely to change, there is a need to link various existing computer networks. Such development requires leadership, which could be provided by a committee of EEZ data system participants, a U.S. government interagency group, or an academic or industrial systems organization. Security of data will require careful attention, especially in an open, highly distributed, data management system. There are three main aspects to securing data: control of access, control of expenditure of resources, and damage to data sets and other resources. Government leadership will be vital for establishing a comprehensive data management system and implementing standards to facilitate the easy exchange of data, while at the same time maintaining the appropriate level of security. The most important function of such a system is to provide coordination and management of a widely dispersed database. Users must be able to access information about data, i.e., what data are available and how to obtain them.