ratio for calculating the quantity of sand to be dredged to yield a given quantity of sand on 

 the beach. Tlie method for determining the ratio is given by Krumbein and James (1965) 

 and in the Shore Protection Manual (U.S. Army, Corps of Engineers, Coastal Engineeing 

 Research Center, 1973). 



Factors affecting the quality of a potential borrow site other than the character of 

 included sand are: uniformity of the sand throughout the deposit, accessibility to dredging, 

 proximity to the project site, and thickness of the deposit. Based on these suitabihty factors 

 the best sediment in the study area is the coarser facies of type A quartz sand. Type A sands 

 are composed predominantly of mechanically and chemically stable quartz particles, are 

 generally free of fines and objectionable inclusions which might degrade the recreational 

 quality of a beach and, being the characteristic surficial deposit, are readily accessible to 

 dredging. 



The characteristic thinness of type A surficial sand is its chief potential drawback to 

 exploitation since it hmits the most suitable borrow sites to certain locales. These are 

 extensive areas of inner shelf where type A sediment mantles the bottom to only a few feet 

 in thickness, and thus dredging would affect a relatively large area to recover a given volume 

 of sand compared to dredging a thicker deposit. In addition, dredging thin deposits may 

 uncover a different substrate, consequently changing the character of tlie bottom in the 

 borrow area. 



Sediments of silty fine sand (Type F) which characteristically form the surficial deposits 

 of the shoreface and contiguous innermost ramp are considered to be generally unsuited for 

 nourishing north Florida beaches because of their fine size and silt content. 



Sediments classed as type G are also considered generally unsuited for beach fiU because 

 of the high sheU-gravel content, strongly bimodal size characteristics, and apparent 

 nonuniformity of characteristics within deposits. Further, type G sediments were usually 

 found under an overburden of dissimilar material sometimes several feet thick. 



Type L sediment is composed of up to 50 percent calcium carbonate in the form of 

 silt-size calcareous grains and sand-size foraminiferal tests. The large content of sUt in the 

 high energy beach zone would likely result in excessive loss of fines should this material be 

 placed on a beach. 



Exposures and near exposures of type M sand deposits are accessible in places along the 

 northern part of the study area. Available indirect evidence from seismic reflection data 

 indicates that the deposit of type M sediment may be over 50 feet thick in places. 

 Therefore, where deposits are accessible, it should be possible to recover large amounts of 

 sand with a minimal area directly affected by dredging. Size distribution of the sand fraction 

 of type M sediment is within ranges suitable for beach fill in nearby coastal areas. A possible 

 drawback to use of type M sediment is its content of silt-size dolomite crystals or, in places, 

 silt-size particulate organic matter; also the deposit may be litliified below the uppermost 

 section penetrated by cores. 



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