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modification of the surrounding beach and nearshore profile, and the net trans- 

 port direction of the disposal sediment. 



The sediment piles initially created a local shoal zone with minimum depths 

 of 0.6 meter. Disposal sediment was coarser (Mn = 0.49 millimeter) than the 

 native sand at the disposal site (Mn = 0.14 millimeter) and coarser than the 

 composite mean grain size of the entire profile (Mn = 0.21 millimeter). Shoal- 

 ing and breaking waves caused rapid erosion of the pile tops and a gradual coa- 

 lescing of the piles to form a disposal bar located seaward (== 90 meters) of a 

 naturally occurring surf zone bar. As the disposal bar relief was reduced, the 

 disposal bar-associated breaker zone was restricted to low tide times or periods 

 of high wave conditions. 



The disposal bar eventually migrated landward, in some cases at a rate be- 

 tween 2.5 and 4.5 meters per day, although movement appeared sporadic and to 

 coincide most directly with periods of increased wave activity. With develop- 

 ment of the disposal bar, the inner surf zone bar was displaced landward. Sedi- 

 ment, some similar in appearance to disposal sediment, filled the inshore surf 

 zone trough located landward of the surf zone bar. The trough downdrift from 

 the disposal site also became choked with this type of material, evidencing 

 longshore transport. In some cases, accretion occurred along the lower end of 

 the seaward flank of the disposal bar, possibly as a result of slope adjustment 

 and onshore sediment transport. 



Final surveys showed accretion at the base of the foreshore, complete fill- 

 ing of the surf zone trough, a platform or new trough at the initial surf zone 

 bar position, disappearance of the surf zone bar, and generally a more seaward 

 surf zone boundary. Profiles adjacent to the disposal area showed slight ac- 

 cretion seaward of the surf zone. The predominant transport direction of dis- 

 posal sediment was shoreward into the surf zone (in the direction of the coars- 

 est native sand) and then in the direction of the longshore current. 



During storms, the disposal bar served as a storm bar with major transport 

 occurring in a shore-parallel direction along the bar axis. The increased width 

 of the platform-disposal bar complex may provide additional benefits by in- 

 creasing the amount of wave energy dissipation in the surf zone and hence, less 

 ening erosion of the beach. 



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