Division, Missouri River, laboratory, analyzed the 1972 samples using a 

 Visual Accumulation (VA) Tube. The dry sieve method was used by project 

 technicians to analyze 10 percent of the samples for quality control- 



a. RSA Method . Analysis with, the RSA consisted of allowing a split 

 sample to settle through the tube while the pressure differential was 

 measured with a pressure transducer, and the values digitized and punched 

 onto IBM cards. The cards were used with the program SEDANL (on file in 

 CERDP) to obtain a detailed listing of percentages in each 1/4 phi-size 

 interval and other statistical parameters. Ramsey and Galvin (1977) give 

 details on the use of this method. 



b. VA Tube Method . Analysis by the VA Tube method consisted of allow- 

 ing a split sample to settle through the tube while manually following the 

 accumulation of sediment at the bottom of the tube. Colby and Christensen 

 (1956) describe the use of this method. 



c. Sieve Method . Sieve analysis consisted of pouring dried 50-gram 

 samples into a nest of sieves (sizes 2.00, 1.00, 0.500, 0.354, 0.250, 0.177, 

 0.125, 0.088, and 0.062 millimeters), and then placing the samples in a 

 Rotap machine for 15 minutes. Weight measurements were made on the 

 Ainsworth analytical balance (graduated to 0.0001 gram). 



d. Comparison . A comparison of the three techniques showed that the 

 RSA median grain size was larger than the sieve median by 0.04 millimeter 

 on the average, and the VA Tube median was smaller than the sieve median 

 by 0.01 millimeter. The data also show that the average median (by sieve) 

 of samples at the beginning of the experiments became finer, falling from 

 0.23 millimeter in 1971 to 0.22 millimeter in 1972. The size-distribution 

 curves for two samples collected at hours in experiments 71Y-06 and 

 72D-06, and the analysis of each sample by two of the three methods, are 

 shown in Figure 18. The RSA median was 0.04 millimeter higher than the 

 sieve median for the same sample, and the VA Tube median was 0.01 milli- 

 meter lower than the sieve method for the same sample. The sieve median 

 in 1972 was 0.01 millimeter lower than the sieve median in 1971. 



The difference between the RSA and sieve methods for this sand was 

 0.24 phi; Ramsey and Galvin (1977) found the difference between RSA and 

 sieve methods to be 0.33 phi for samples from New Jersey beaches. 



X. WATER TEMPERATURE AND CURRENT DATA 



1 . Water Temperature . 



Water temperature was measured (in "Celsius) in samples collected at 

 the bottom of the tank and at the water surface in the morning and after- 

 noon of each test day. The water sampler could be manipulated to ensure 

 that samples were actually taken from the bottom of the tank. These data 

 were recorded in the logbooks, and the four values were averaged to give 

 a daily mean temperature. 



43 



