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These systems provide a capability to address several important 

 issues of value to the U.S. Navy in shallow water areas. They also can be 

 used to address numerous issues of importance to the private sector. An 

 example of such an issue is to rapidly assess the potential of areas, such 

 as the Chesapeake Bay, to grow oyster beds on artificial reefs. Successful 

 oyster growth is generally endemic to shallow, coastal/estuarine areas. 

 Of particular importance in this case is the establishment of appropriate 

 hard-surface growth substrata for the young oyster. The classification 

 technologies developed by ONR and NRL could potentially identify areas 

 which have subbottom structures with adequate bearing strength to 

 support the development of artificial reefs (e.g. old automobile tires). 

 These reefs, once established, can be seeded and developed Into productive 

 oyster-bearing beds. 



DEEP-TOWED MAPPING SYSTEMS 



Several Deep Towed Mapping Systems (DTMS) systems have been 

 developed capable of providing very high-resolution, optical and/or 

 acoustic profiles of the ocean bottom and subbottom structure. The NRL- 

 developed Deep Towed Acoustics/Geophysical System (DTAGS) derives its 

 high-resolution potential by placing both the acoustic projector and its 

 multi-hydrophone linear array receiver near the bottom. This geometry 

 makes it possible to obtain detailed characterizations of the structure of 

 the sediments, compressional velocities within the sediments, and 

 acoustic bottom loss as a function of acoustic grazing angle and 

 frequency. This knowledge is useful in ASW, MCM and MIW. 



DTMS have been used to define significant areas of clathrates 

 (frozen methane gas) in these surficial sediments. The presence of these 

 apparently extensive gas pockets may have a significant impact on future 

 energy availability issues and air and water pollution concerns. 

 Cooperative research discussions on clathrates have occurred with DOE. 



DTMS also offer significant potential for NOAA and USGS with regard 

 to requirements for mapping the Economic Exclusion Zones of the 

 continental United States and, cooperatively, the EEZ's of other countries. 



