The size of quartz particles in beach sands and those found in 

 selected offshore sediments are within the same size range (Appendix B) . 

 In fact, the quartz fraction (insoluble residue) alone of Type A sediments 

 on Bethel Shoal has a median (and mean) diameter equal to or coarser than 

 the beach sands. 



4. Potential Borrow Areas 



Three of the 12 shoal areas within the Fort Pierce grid are judged 

 to contain the best material for restoration and nourishment of beaches 

 (Figure 25). Two of these: Capron Shoal and the middle section of Indian 

 River Shoal lie close inshore; the third. Bethel Shoal, is located well 

 offshore. Bottom topography, isopach maps and selected profiles for each 

 of these three sites are presented in Figures 26 through 35. 



Bethel Shoal contains an estimated volume of 175 x 10 cubic yards 

 of unconsolidated material above the blue horizon (Figure 26) . Good Type 

 A material was obtained in cores 69 and 71 on the upper part of the shoal 

 to a minimum depth of ~ 10 feet. The lateral extent and total depth of 

 this better material is not accurately known because of limited core data. 

 Estimates based on an assumption that the base of the better material is 

 either at the first or second continuous subbottom reflector within the 

 shoal proper (reflectors x and z. Figure 27) give volumes of 16.5 x 10 

 cubic yards and 55.2 x 10" cubic yards respectively (Figures 28 and 29). 

 On the basis of existing data, it seems most probable that the volume 

 above the first reflector is the best estimate and that below this 

 reflector the material is considerably finer in texture. 



Capron Shoal, centered about 4 1/2 miles southwest of Fort Pierce 

 Inlet and 3 miles offshore, contains an estimated volume of 112 x 10^ 

 cubic yards of sediment above the blue reflector (Figures 30 and 31) . 

 Cores 32 and 53, taken near the crest of Capron Shoal, contain about 7 

 feet of Type A sediment. Underlying the Type A layer is a Type D strata 

 of poorer quality. The base of usable material is believed to correlate 

 with a reflector in the shoal proper (first subbottom reflector) in 

 Figure 31. Volume above this reflector is 65.4 x 10^ cubic yards 

 (Figure 32) . 



Core 38 in the middle section of Indian River Shoal contains suitable 

 material to the bottom of the core (10 feet long) (Figure 33) . It is 

 believed that the material rests directly on the blue reflector (Figure 

 34) . Assuming that it does extend to the blue reflector, the volume 

 of usable sand in middle Indian River Shoal is 10.3 x 10^ cubic yards 

 (Figure 35). Elsewhere, Indian River Shoal may contain comparable 

 material ; cores 41 and 43 on the shoal section south of the middle 

 contain fair material (Type A) . 



In addition to the three possible borrow sites above, other shoal 

 areas in the Fort Pierce grid, all containing Type A sediment, may be 



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