replenishment and the general features of the beach for each station 

 surveyed. Significant beach features are summarized in Table 3. 

 Changes in beach topography are shown by photos in Figures 5 and 6. 



Intertidal survey I (22, 23, and 24 September 1976) was conducted 

 toward the end of the southern California summer at a time of maximum 

 seasonal beach accretion. All three intertidal stations were fine 

 sandy beaches with small but well-developed barms and no surge channels 

 or sandbars. 



Survey II (14, 15, and 16 February 1977) stations all had some 

 sand loss, probably due to winter waves. Station B was extensively 

 eroded with the upper intertidal consisting exclusively of cobble with 

 large surge channels. This correlated with the lowest abundances of 

 intertidal organisms in any survey. 



Survey III (2 June 1977) was conducted 2.5 weeks before the end 

 of beach replenishment and the dredge pipe was located 290 meters north 

 of station B. However, it was evident from the beach profile that 

 sediment had accumulated at this station. Intertidal station B was 

 covered with 2 to 3 centimeters of a fine silt layer over large shell 

 fragments and some gravel. 



Survey IV (postdisposal, 27, 28, and 29 July 1977) was conducted 

 during a period of low wave energy (Fig. 7). Stations A and B had 

 wide berms while station C continued to lose sand. 



Survey V (10, 11, and 12 November 1977) found 20 percent of the 

 beach width at station A eroded since Survey IV (107 days). Major 

 sand loss occurred at both stations A and B while station C showed 

 little sand loss but had more cobble in the upper intertidal. 



On 24 March 1978, a return visit to all stations found a steep 

 beach slope at station A with an estimated 60 percent of the added 

 sediments having been eroded from this station since Survey IV (242 

 days) (Figs. 4 and 5). Station B appeared to have some sand loss 

 but no measurements were taken; station C had eroded to almost ex- 

 clusively cobble with no sand exposed at low tide (Fig. 6). The 

 considerable erosion of these beaches was largely due to heavy winter 

 storms which were of an intensity to be expected once in 10 years. 



2. Grain-Size Analysis . 



The median grain diameter for Imperial Beach has been reported as 

 200 micrometers (Dexter, 1977; Muslin, 1978); however, this study found 



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