characteristics (Meisburger and Duane, 1969), analysis of shelf history and sediment sources 

 (Duane, et al., 1972; Pilkey and Field, 1972; Field, 1974) and determination of regional 

 engineering properties of shelf sediments (WiUiams and Duane, 1972; Field and Duane, 

 1972; Williams, 1973). 



An early study by the Corps of Engineers in evaluating techniques for transferring 

 offshore sand to the beach is described by MaurieUo (1967). This experiment at Sea Girt, 

 New Jersey, involved dredging of 250,000 cubic yards of sand by use of the hopper dredge 

 Geothals at a location 2 miles offshore from the beacii segment to be restored. The loaded 

 dredge, wliich had a pumpout capabiUty, docked alongside an anchored barge and the sand 

 was pumped ashore through a submerged pipeline. 



At Redondo Beach, CaUfornia, in 1967-68, the U.S. Army Engineer District, Los 

 Angeles, contracted dredging of over 1.4 million cubic yards of sand from offshore in 40 

 feet of water and transfer to the beach. The dredging contractor used a 16-inch hydraulic 

 dredge with powerful water jets for agitation in lieu of a normal cutterhead on the ladder. 

 These operations as well as others conducted in open-ocean inlet mouths and in Long Island 

 Sound and along the gulf coast have demonstrated the feasibility of using offshore marine 

 and lake deposits for beach restoration and periodic nourishment operations. 

 2. Field and Laboratory Procedures. 



Tlie exploration phase of the ICONS program uses seismic reflection profiling 

 supplemented by cores of the marine bottom. Additional supporting data for the studies are 

 obtained from National Ocean Survey (NOS) hydrographic smooth sheets and pertinent 

 pubUshed literature. Planning, seismic reflection profiling, coring, positioning, and analysis 

 of sediment obtained in tlie cores are detailed in Geomorphology and Sediment 

 Characteristics of the Nearshore Continental Shelf, Miami to Palm Beach, Florida (Duane 

 and Meisburger, 1969). However, a brief description of tecliniques follows: 



a. Planning. Survey tracklines were laid out initially in grid or reconnaissance Unes. A 

 grid pattern (Une spacing of about 1 or 2 statute miles) was used to cover areas where a 

 more detailed development of bottom and subbottom conditions was desired. 



Selection of core sites was based on a continuing review of the seismic profiles as they 

 became available during the survey. This procedure allowed core-site selection based on the 

 best information available; it also permitted the contractor to complete coring in one area 

 before moving liis base to the next area. 



b. Seismic Reflection Profiling. Continuous seismic reflection profiling is a technique 

 for delineating subbottom structures and bedding planes in sediments and rocks underlying 

 water-covered areas. Continuous reflections are obtained by generating repetitive 

 high-energy, sound pulses underwater near the water surface and recording "echoes" 

 reflected from tlie bottom-water interface, and subbottom interfaces between acoustically 

 dissimilar materials. In general, compositional and physical properties which commonly 

 differentiate sediments and rocks also produce acoustic contrasts. Thus, an acoustic profile 

 is roughly comparable to a geologic cross section. 



