of equilibrium with the sea environment, it is possible to minimize the 

 losses through careful selection of the most suitable fill material (U.S. 

 Array, Corps of Engineers, Coastal Engineering Research Center, 1973). 



The problems of locating suitable and economical sand deposits led 

 the U.S. Army, Corps of Engineers, Coastal Engineering Research Center 

 (CERC) to initiate a search for exploitable deposits of sand. Explora- 

 tion efforts are focused offshore with the intent to locate and inventory 

 deposits suitable for future fill requirements and to later refine tech- 

 niques for specifying more suitable fill characteristics. 



The search for offshore sand deposits, referred to initially as the 

 Sand Inventory Program, started in 1964 with a survey off the New Jersey 

 coast (Duane, 1969). Subsequent data collection surveys have included the 

 Inner Continental Shelf areas off New England, Long Island, Delaware, 

 Maryland, Virginia, the Cape Fear area of North Carolina, the east coast 

 of Florida, and southern California. A survey for eastern Lake Michigan 

 was initiated in August 1975. Since 19 71, broader application to the 

 CERC mission of the data collected has been recognized, especially in 

 deciphering the shallow structure of the Continental Shelf, understanding 

 shelf sedimentation and hydraulic processes, unravelling geologic history 

 of the shelves, and finally, evaluating the potential for engineering 

 design of manmade structures on the shelf. This more diversified program 

 is now referred to as the Inner Continental Shelf Sediment and Structure 

 (ICONS) program. 



2. Field and Laboratory Procedures . 



The field exploration phase of the ICONS program uses continuous high- 

 resolution seismic reflection profiling, supplemented by cores of the sub- 

 bottom sediment. Both of these sources of data are obtained by contrac- 

 tual agreement with ocean industry firms. These data are then analyzed 

 and interpreted by CERC Geological Engineering Branch staff. Support 

 data are obtained from the National Ocean Survey hydrographic boat sheets, 

 pertinent professional papers, and published literature. 



a. Data Collection Planning . Geophysical survey track lines are laid 

 out for the study areas by the CERC staff in two basic patterns: grid 

 and reconnaissance lines. A grid pattern, with variable line spacing 

 depending on regional geologic relationships is used to cover areas where 

 a more detailed picture of sea floor and subbottom geologic conditions is 

 desirable, usually those areas suspected of containing sand and gravel. 

 Reconnaissance lines consist of one or more continuous shore-parallel or 

 zigzag lines which provide minimal coverage for intermediate areas between 

 grids. Reconnaissance lines also provide a correlation of regional geology 

 between grid areas. They normally provide sufficient information to reveal 

 the general morphologic and geologic aspects of the area and to identify 

 sea floor areas where more detailed additional data collection may be 

 advisable. 



