of sand per foot (49 cubic meters per meter) beach length were eroded 

 from the beach face between +7 feet (2.1 meters) and -7 feet (-2.1 meters). 

 This erosion was matched by an accretion of about 600 cubic feet of sand 

 per foot (56 cubic meters per meter) beach length in depths of -8 to 

 -25 feet (-2.5 to -7.5 meters) below mean sea level. Thus, it appears 

 that most of the sand eroded from the upper part of the beach was trans- 

 ported immediately offshore and deposited at shallow depths. 



The profile measurements at Indian Canyon and South Ranges show 

 similar changes in profile configuration and volumes of offshore sand 

 transport related to the storm. This major change in beach configuration 

 was caused by high surf (up to 10-foot breakers) coincident with +6 to 

 +7-foot-high (1.8 to 2.1 meters) tides during the 4-day storm. The 

 high tides enabled the storm surf to overtop the berm crest and quickly 

 erode the beach. 



After the storm of 18-20 November 1972, Torrey Pines Beach main-' 

 tained a winter beach profile configuration with a more gentle foreshore 

 slope. Subsequent storms of lesser intensity during the winter months 

 caused additional erosion of the beach face and accretion at shallow off- 

 shore depths. Comparison of beach profiles from the three range lines 

 indicates that the beach responded to the winter storm waves in a similar 

 manner along the full length of the study area. 



Figures 6a, b, and c show the progressive retreat of the berm crest and 

 related offshore accretion of sand from November 1972 to April 1973 dur- 

 ing the winter. As can be seen, most of the total amount of sand eroded 

 from the beach face during the winter was removed by the storm in Nov- 

 ember 1972. The remainder of the sand transported offshore during the 

 winter was progressively removed over several months. 



Beach profile and reference rod measurements made on 11 April 73 

 show the final winter configuration of the beach profiles with maximum 

 retreat of the berm crest and the lowest foreshore slope. Figure 8 

 shows two representative profiles measured at North Range which indicate 

 the magnitude of the total seasonal change in profile configuration. 

 A comparison of the 23 October 72 and 11 April 73 profiles shows the 

 total amount of sand involved in the seasonal change in beach config- 

 uration. The quantity of sand eroded from the beach was about 1,500 

 cubic feet per foot (121 cubic meters per meter) beach length, and the 

 quantity accreted offshore totaled 880 cubic feet per foot (82 cubic 

 meters per meter) beach length. The inequalities in the amount of sand 

 eroded from the upper beach and the amount accreted offshore are pro- 

 bably a result of longshore transport of sand away from the vicinity of 

 the range line. Measurements made on the other range lines indicate a 

 similar seasonal change for the entire section of beach under study. 



25 



