The area between profiles PL-5 and PL-7 neared a welded beach profile 

 (Fig. 42) at the conclusion of the study period. Ridges of sediment grad- 

 ually filled in the runnel, and on 9 August the last remaining ridges had 

 nearly welded (Fig. 43). A principal reason for the late welding of the 

 central profiles was the strong runnel currents created by the lower 

 elevation" of this area. As sediment was transported across the ridge 

 surface and over the slip face, it was caught by the currents in the 

 runnel and transported seaward. 



The net erosion and deposition for the study period are shown in 

 Figure 41 which compares profiles on 2 July with those of 9 August. The 

 northern and southern ends of the study area had the greatest accretion, 

 while the central profiles had considerably less net accretion. The 

 areas of greatest net erosion (PL-2, PL-6, PL-8, and PL- 10) are due to 

 ridges which were present on 2 July and had migrated landward before 

 9 August. 



The adjacent zones of mature and early accretionary profiles resemble 

 the rhythmic topography of Hom-ma and Sonu (1962) and Sonu and Russell 

 (1966). According to Sonu and Russell (1966), sand wave phenomena along 

 a shoreline may cause profiles "resembling the accepted summer and winter 

 types to be encountered barely several hundred feet apart on the same 

 stretch of beach." This explanation appears to be true in a general 

 sense; however, the coexistence of adjacent profiles at different stages 

 of maturity is directly related to the proximity of the nearshore bar 

 and the availability of sediment to be moved onshore. The fact that 

 during periods of uninterrupted accretion, mature profiles will develop 

 at all profile locations, differs from Sonu's (1968) model of zones of 

 net erosion on the shore in the lee of the sand wave or shoal (Fig. 44). 



V. WINTER BEACH PROCESS MEASUREMENTS 



Measurements were taken in the winter study period on all the beach 

 process variables studied during the summer period, except for ground 

 water elevation. Higher energy conditions were encountered more often 

 during the winter than during the summer. These higher energy periods 

 were associated with storms (5 January 1972 and 19 February 1972), and 

 with the passage of high-pressure systems through the area and the strong 

 northwesterly winds accompanying the highs. 



1. Meteorological Measurements . 



Barometric pressure, windspeed, and wind direction measurements for 

 the winter period are shown in Figure 45. The relationship between baro- 

 metric pressure, windspeed, and wind velocity is more direct for the 

 winter study than for the summer study. As the area comes under the 

 influence of a polar high-pressure system, the winds shift to the west 

 or northwest as the barometric pressure is rising. The change in wind 

 direction occurs 8 to 12 hours before the extreme high pressure is 

 reached and will usually shift to the south or southwest as the center 



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