and deepwater fall velocity parameter, H„/wT , where the deepwater wavelength 

 is calculated from the wave period data using L = gT 2 /2w , where g = accel- 

 eration of gravity or 9 . 8 m/sec 2 . This expression can be simplified to 

 L = 1.56 T 2 (m) . With the availability of wave data for the study, the 

 deepwater significant wave height was calculated from the gage data, using an 

 average wave height from the 24-hr before the profile (wave data was collected 

 every 6 hr) and sediment sampling were taken. The corresponding 24-hr average 

 spectral peak wave period was also used. 



54. Several combinations of grain-size data were applied to the calcu- 

 lations for fall velocity to see the changes in data spread and to determine 

 the best grain-size data to use in the calculation procedure. Figure 27 shows 

 the plot of criteria for distinguishing bar and berm profiles or erosion/ 

 accretion using median grain size (D x ) data to determine sediment fall veloc- 

 ity. The sediment fall velocity was calculated using composite D^ data from 

 the beach group, the nearshore group, and the entire profile composite for 

 each sample day. 



55. Figure 28 shows the erosion/accretion using mean grain size instead 

 of median values for the same three groups of the beach, nearshore, and pro- 

 file. The division line is the same as in the median plots. The substitution 

 of mean values rather than Dj,, values for the calculation of the sediment 

 fall velocity shows little differences in placement of data points. The dif- 

 ferences are greatest for some of the bimodal beach samples. For unimodal 

 samples that are reasonably well sorted, the mean and the median are very 

 similar, and either analysis could be used. 



56. These plots give a line representing the criterion representing the 

 division between erosion and accretion of H /L = 0.00027 H /wT reported in 

 Kraus (1990) based on field data. A second criterion was also described by 

 Kraus (1990) for identification of an erosional profile from an accretional 

 profile by using a single value of H„/wT =3.2 . Values of H /wT > 3 . 2 

 indicate that erosion is predicted, and values of H /wT < 3.2 indicate that 

 accretion is probable. An identification of erosion and accretion for this 

 study was to chose whether the profile experienced a net loss of material from 

 the previous profile or a net gain respectively and is indicated as such in 

 Figures 27 and 28. Due to the irregular temporal spacing of profiles, this 

 may not be a good indicator for differentiation in this model. Since wave 



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