immediately seaward of the offshore bar (surf zone bar) , moved shoreward and 

 accreted to the beach, as long as placement was in the simulated early summer 

 wave cycle (small storm wave conditions) and was as high on the profile as 

 possible within the reach of summer waves. The material placed below the crit- 

 ical depth for entrainment was moved seaward by large storm waves (winter con- 

 ditions) and did not return shoreward in response to ensuing small storm waves. 

 Similarly, seaward "trapping" resulted from sediment placement on the seaward 

 adjusted winter storm profile when followed by summer (small storm) waves. Pre- 

 sumably, the seaward displaced sand was below a critical depth for entrainment 

 by the small-scale waves. The study demonstrates that, at least in the labora- 

 tory, onshore transport and accretion of placed sand should occur as a result of 

 certain placement conditions, i.e., the location on the profile and the season. 

 It is questionable though that such loss would be permanent in the field where 

 a wider and more continuous spectrum of wave conditions occurs. Although not 

 a beach or offshore nourishment experiment, Nordstrom and Inman's (1975) study 

 provides support that such a loss may not be permanent in the field. After ex- 

 amining seasonal variation in profiles, they concluded that sand was transported 

 offshore from the beach face during the winter seasonal change and deposited in 

 depths of -3 to -9 meters. This change occurred abruptly with the coincidence 

 of high waves and tides. They further concluded that summer beach accretion 

 resulted from a progressive onshore migration of sand from water depths of less 

 than 10 meters. A net offshore loss was not apparent. 



Field experiments involving offshore placement have only been partially 

 successful. Experiments in which the disposed material showed neither systematic 

 movement nor any evidence of benefit to the beach were conducted at Long Branch, 

 New Jersey (Hall and Herron, 1950; Harris, 1954) Atlantic City, New Jersey (Hall 

 and Watts, 1957), and Santa Barbara, California (Wiegel, 1964). Approximately 

 460,000 cubic meters of sand was placed 800 meters offshore from the Long Branch 

 beach in 10- to 12-meter water depths. The average grain size of the placed 

 sand was 0.34 millimeter, the offshore sand 0.32 millimeter, and the beach sand 

 0.66 millimeter. It was concluded that most of the time, wave action was not 

 sufficient to move sand at that depth, and when sand did move, it did so 

 "haphazardly." At Santa Barbara, approximately 153,000 cubic meters of sand was 

 dredged from the harbor and placed in 6.7 meters of water 300 meters from shore. 

 The placed sediment formed a mound about 670 meters long and 1.5 meters high. 

 Surveys conducted 9 years later showed essentially no change in the mound, indi- 

 cating no significant transport had occurred. Although sand was placed in shal- 

 lower water for the Atlantic City experiment (water depth = 4.5 to 6.1 meters), 

 there was insufficient information to evaluate the apparent failure of onshore 

 nourishment. Harris (1954) concluded that for sand to move shoreward and bene- 

 fit the beach, placement should be in depths less than 6 meters. 



Offshore nourishment projects at Copacabana Beach, Brazil (Vera Cruz, 1972) 

 and the Limfjord Barriers, Denmark (Mikkelsen, 1977) were highly successful. 

 Similar aspects for both of these projects are: (a) The placed sand was sim- 

 ilar in size (or slightly coarser) than the native beach sand, (b) placement 

 was in depths between the -4- and -6-meter contour, and (c) placement was gener- 

 ally between shore-normal structures. The Copacabana Beach is crescentic in form 

 and bordered at each end by a natural promontory. Disposal for the Limfjord 

 Barrier project was between and slightly seaward of two groins. In both cases, 

 direct onshore accretion of the beach resulted. At Limfjord, the disposed sand 

 formed a bar which moved continually toward the beach, and, approximately 1 year 

 following disposal, the profile became a seaward adjusted form without any bar. 



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