2. Littoral Processes . 



a. Wind Speed and Direction . Figure 6 compares the long-term average 

 wind speed and direction at Wilmington, North Carolina, 56 kilometers north- 

 east of Holden Beach, from 1948 to 1960 (U.S. Army Engineer District, 

 Wilmington, 1973), with the wind speed and direction during the study period 

 (1970-74). The predominant winds, both in terms of duration and speed, occur 

 from the southwest direction. Winds from the southwest were more persistent 

 than normal and, in all cases, were more moderate than normal. There were 

 no significant storms during the study period. Winds from the south and 

 southwest predominate during the spring and summer months; north and north- 

 east winds occur during the winter. All sections of Holden Beach are vulner- 

 able to hurricane winds from the south and east (Carney and Hardy, 1967). 



b. Wave Climate . A continuous -wire staff wave gage, installed on the 

 fishing pier at Holden Beach in February 1971, recorded wave height and 

 period for 1,024-second intervals every 4 hours through February 1975, as 

 shown in Figure 7 (Thompson, 1977). Figure 8 shows monthly averages of 

 significant wave heights and periods from April 1971 to December 1974 and 

 the composite mean for the entire period; the vertical lines represent the 

 standard deviation. Periods of calm, according to visual observations over 

 the same period, comprised fewer than 1 percent of the readings. The highest 

 average waves were observed in June, though this may be an anomalous month 

 since only 19 72 was recorded. Mean wave heights were greater than 60 centi- 

 meters from February through August with the least mean height recorded in 

 October. Mean wave periods for the interval were 7.38 seconds with longest 

 periods in September and November and shortest during April, June, and July. 

 The general wave height at Holden Beach is less severe than recorded by 

 CERC wave gages to the north at Wrightsville Beach and south at Savannah, 

 Georgia (Fig. 9). Holden Beach, exposed to the south, is protected from 

 severe northeast storms and large, long-period ocean waves approaching from 

 the east. Wrightsville Beach and Savannah are fully exposed to these waves 

 (Fig. 1). 



U.S. Army Engineer District, Wilmington (1973) considered the direction 

 and rate of littoral transport along the east end of Holden Beach and other 

 beaches (Long Beach and Yaupon Beach) immediately to the east. Although 

 several sources of wave data were evaluated, transport rates and directions 

 were determined using computer-generated wave refraction data for selected 

 combinations of wave heights, periods, and angles of approach. The Wilmington 

 District concluded that the dominant direction of transport is west to east, 

 and that the magnitude of the easterly component ranges is 2.5 to 3.5 times 

 the westerly component. 



Littoral Environment Observations (LEO) of breaker height, period, and 

 angle to the shoreline at Holden Beach were recorded by a trained observer. 

 These observations were made by the same person at the same general loca- 

 tion along the beach (i.e., near profile line 16) throughout most of the 

 study period. Before 1974, breaker angle was recorded as approaching from 

 a sector rather than from a discrete direction (Everts, DeWall , and Czemiak, 

 1980). These data, which were later converted to the LEO format, assigned 

 sectors 2, 3, and 4 corresponding to 72°, 90°, and 108° clockwise from the 



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