1 foot to at least 10 feet, and possibly as much as 30 feet. Thickness 

 of the deposit is closely related to topography, being at a maximum 

 under topographic highs. Most of the sand in the surficial layer. Type 

 A, is usable for beach fill on adjacent beaches, but the characteristics 

 vary considerably. The best material can be obtained only by selective 

 borrow . 



Sand suitable for beach restoration exists on Bethel Shoal (minimum 

 volume 16.5 x 10 cubic yards); Capron Shoal (minimum volume 65.4 x 10° 

 cubic yards) and the middle section of Indian River Shoal (minimum volume 

 10.3 X 10 cubic yards). Good material is indicated in a northwesterly 

 trending shoal between Capron and St. Lucie Shoals, in an lonnamed shoal 

 lying 6 miles northeast of Fort Pierce Inlet, and in an unnamed shoal 

 extending northeast from Fort Pierce Inlet. By analogy. Pierce Shoal, 

 St. Lucie Shoal and Gilbert Shoal are considered good prospects for beach 

 fill even though direct evidence is lacking. 



Some shelf material seaward of 70-foot water depth may be suitable 

 for borrow. However, careful survey of potential borrow sites is needed 

 because of the large number of indurated strata in these deeper water 

 deposits and the variable extent and thickness of unconsolidated strata. 



Shelf sediments in the grid area are judged to be largely relict, 

 and little active sedimentation now takes place outside the shoreface, 

 i.e., beyond -^40 feet MLW. Rate and volume of sediment generated by the 

 benthic fauna is not known. Sand removed from the shelf is not likely 

 to be replaced quickly nor by sand-sized material from sources outside 

 the grid. 



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