APPENDIX B 

 RESULTS OF GRAIN-SIZE ANALYSIS 



This appendix provides a list of mean grain size and sorting for 

 samples analyzed by sieving and settling-tube techniques. Sieve data 

 (Table B-l) were obtained by sieving samples at 0.5 -phi intervals for 

 periods of 20 to 30 minutes. Raw weights were used to calculate mean 

 grain size and sorting by use of the method of moments. 



Settling-tube data (Table B-2) were obtained by analyzing samples 

 on the CERC Rapid Sediment Analyzer (RSA) . The RSA method records at 

 the top and bottom of a 1 -meter-long (3-inch-diameter) plastic tube as 

 grains settle through the water column through use of two pressure trans- 

 ducers. Pressure data are digitized and converted to equivalent size 

 data of spherical quartz grains, and mean grain size and sorting are 

 computed by the method of moments. Through comparison of the results of 

 samples analyzed by both the RSA and sieving techniques, empirical rela- 

 tionships were developed for converting data obtained on the RSA to its 

 sieve equivalent. These expressions, given below, were used to convert 

 RSA means and sorting values to their sieve equivalents as shown in 

 Table B-2. 



Mean: 5 . = 0.1876 + 1.0735 cf> „ 

 S%eve RSA 



Sorting: S, = -0.146 + 1.453 S A 



* Sieve *RSA 



Conversion between phi units and millimeters for grain diameters is 

 possible using the Wenworth grain-size scale (Table B-3) . The techniques 

 are discussed in the Shore Protection Manual (U.S. Army, Corps of Engi- 

 neers, Coastal Engineering Research Center, 1977). 



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