( 16 August 1959) 

 Figure 4-45. Sediment trapped inside Old Drum Inlet, North Carolina. 



water offshore, and (3) the slight offshore component of gravity which acts on 

 both the individual sediment particles and on the sediment-water mixture. 



It is often assumed that the sediment sorting loss that commonly reduces 

 the volume of newly placed beach fill is lost to the offshore slopes (U.S. 

 Army Engineer District, Wilmington, 1970; Watts, 1956). A major loss to the 

 offshore zone occurs where spits build into deep vater in the longshore 

 direction; Sandy Hook, New Jersey, is an example (see Fig. 4-47). 



The calculation of quantities lost to the offshore zone 

 since it requires extensive, accurate, and costly surveys, 

 offshore changes can be obtained by studies of sand level changes on rods 



is difficult. 

 Some data on 



4-121 



