function of the transformation of waves from transitional to shallow water as 

 they passed over this region on their way to the beach. 

 Dune group 



32. There is a wide variation in the grain-size distributions of each 

 of the four groups of sediment across the profile, related to the different 

 forcing functions responsible for controlling deposition in each region of the 

 profile and the available mineralogy. Figure 12 shows an example of the dune 

 group grain-size distributions from Station 1 on the top of the dune and Sta- 

 tion 2 on the front face of the dune. This dune is characterized by a rela- 

 tively coarse sediment, probably because the dune was bulldozed from surround- 

 ing coarse beach sands in the 1930' s. The frequency curve of Station 1 has a 

 trimodal distribution, while Station 2 has a bimodal one, indicating the pos- 

 sibility of multiple sources for the dune components. Wind- induced sediment 

 transport is active in daily deposition within the dune area and controls 

 deposition of the finer sand sizes, while the coarser material is probably a 

 lag deposit. 



33. In order to investigate the temporal and spatial distribution in 

 the sediment in this study, plots of individual mean grain size were compared 

 with sample sorting. Figure 13 shows the mean versus sorting plot for all the 

 sediment samples collected at Stations 1 and 2. They are both tightly 

 clumped, indicating little variation through time in sediment characteristics. 

 These samples were, for the most part, unaffected by temporal changes in 

 coastal processes, except for wind transport. The one outlying data point on 

 each graph is from the first sampling on 20 March 1984, which contained shell 

 material, making that date's sample more poorly sorted and coarser than the 

 rest. 



Beach group 



34. The grain-size distribution was the most varied in space and time 

 within this group. Figure 14 shows a somewhat general example of the fre- 

 quency curves at Stations 3 through 6. Because the environment of deposition 

 changed from eolian transport to swash transport daily as the profile changed 

 in elevation, the beach group sediment grain-size distributions reflected this 

 change. Most of these distributions showed a bimodal distribution, with the 

 main component centering around 0.25 mm (2 4>) and the secondary component 

 centering around 1.0 mm (0 cf>) . 



41 



