VII. SUMMARY 



This study investigated changes during a 10-year period (1962-72) in beach 

 shape, shoreline position, and sand volume above MSL at 20 profile locations 

 on Ludlam Beach, New Jersey. The plan shape of the 7 .5-mile-long, 0.25- to 

 1 . 0-mile-wide barrier island is one in which the inlet shorelines protrude 

 considerably seaward of the indentation near the island ends. Superimposed 

 on that indentation is a shoreline bulge in the vicinity of the Sea Isle City 

 groin system. 



Beach width on the island averaged 260 feet with a range between 90 and 

 350 feet. Foreshore slopes averaged 0.03. Berms were present on 80 percent 

 of the profile lines in August and 13 percent in January. 



Surveys provided data on beach change above MSL, based on the location 

 along the coast and on the time surveyed. Variations in shoreline position 

 were large and associated with location. The average change in shoreline 

 position was -8.2 feet per year. Sand volume losses from above MSL, result- 

 ing from seven storms, averaged 2.6 cubic yards per foot per storm or 90,000 

 cubic yards per storm. Overwash deposition, which occurred along 60 percent 

 of the coast during the severe storm of March 1962, averaged 14.7 cubic yards 

 per foot. However, such overwash events are rare. No significant overwash 

 deposition occurred during this study. Losses on a specific profile line as 

 the result of a storm are not predictable. 



Clear seasonal trends in the volume of sand above MSL were evident. A 

 net accretion occurred from June through October; November through May was a 

 period of sand loss from the subaerial beach. The average difference in sand 

 volume above MSL between the time of minimum sand volume (May) and maximum 

 sand volume (October) was 18 cubic yards per foot. The least difference 

 (< 10 cubic yards per foot) was measured in the Sea Isle City groin system. 



Yearly changes in sand volume on Ludlam Beach varied from a gain of 2.9 



cubic yards per foot (1964-65) to a loss of 4.6 cubic yards per foot (1966-67). 



Net yearly sand volume changes over the 10-year survey interval averaged -1.12 



cubic yards per foot per year (a loss of 40,000 cubic yards per year from the 

 entire island above MSL) . 



Sand volumes on Ludlam Beach increased and decreased in a time-ordered 

 sequence from north to south during the 10-year study, indicating material 

 moved alongshore and above MSL as a sand wave. The sand wave, which moved at 

 a rate of 5 feet per day, had a wavelength of 16,000 feet and a volume of about 

 240,000 cubic yards. The sand wave apparently began after the March 1962 storm 

 deposited about 200,000 cubic yards of material at the north end of the island. 



Sediment transport on and off the beach each year (about 600,000 cubic 

 yards) was somewhat greater than the magnitude of the net longshore transport 

 rate to the south (430,000 cubic yards per year). Longshore transport was to 

 the south from September through May, and to the north in June and July. The 

 gross longshore transport rate was 1,150,000 cubic yards per year. A longshore 

 transport reversal node appears to exist about 1,500 feet south of Corson Inlet. 

 The amount of sand moved on and off the beach each month, above MSL, is directly" 

 related to the wave power expended on the beach. The relationship between yearly 

 wave power and yearly sand volume losses or gains above MSL is less definitive. 



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