general, as the disposal bar approached the surf zone, the migration rate of the 

 bar crest diminished, the disposal bar relief decreased, and the bar shape be- 

 came less prominent. During the 9-week survey period following disposal, the 

 disposal bar form never reached the initial position of the natural surf zone 

 bar. Where the disposal bar became adjacent to the surf zone, the disposal bar 

 form was either eliminated or became rounded and much reduced in relief. 



Between mid-September and mid-October, a period which included at least 

 five minor storms and one large storm, the profiles show accretion in the off- 

 shore zone. In general, most of the sediment buildup occurred where parts of 

 the disposal bar or platform had previously eroded. This is further discussed 

 in Section IV, 3, b. 



Disposal sediment was not placed along profile ranges -1+00, -2+00, and 

 -10+00 flanking the actual disposal area. Buildup in the offshore zone along 

 these profile ranges is, therefore, the result of the natural redistribution of 

 sediment. For the three ranges, time-sequence profiles show essentially no 

 change in shape of the offshore zone during the disposal period and initial 

 postdisposal period. Ranges -2+00 and -10+00, flanking the disposed material 

 ('^ 15 meters away), showed an eventual buildup of sand in the offshore zone 

 later in the postdisposal period (Fig. 14) . Most of the buildup was southwest 

 of the disposal site. The northeast profile range -1+00 ('v 45 meters from the 

 disposal area boundary) showed no accretion in the offshore zone throughout the 

 study period. 



(2) Inshore Subzone . Inshore from the disposal bar, the surf zone bar 

 eroded or was displaced landward (Fig. 13). At the same time, the surf zone 

 trough filled with sediment and became part of the lower foreshore. A platform 

 developed seaward through the surf zone extending to the encroaching disposal 

 bar, creating a wider surf zone. In some cases, a new trough developed at the 

 original site of the surf zone bar. This new trough developed in association 

 with, and immediately landward of, the encroaching disposal bar. 



The surf zone trough in the inshore zone northeast and southwest from the 

 disposal sector also filled (Fig. 14). In most cases, the surf zone bar in 

 these regions remained essentially stationary as the trough simply filled with 

 sediment carried alongshore from the adjacent inshore zone of the disposal sec- 

 tor. At the southwest range -10+00, a new trough was eventually cut at t.he 

 surf zone bar position after the initial trough had filled. This corresponded 

 with a period of moderate storm conditions and high-velocity longshore currents. 

 The trough refilled and a small bar developed during the final month of study. 



(3) Beach Subzone . A low-amplitude ridge developed in the foreshore 

 and migrated to the backshore along all profile ranges (Figs. 13 and 14). The 

 size and relief of the bar initially increased, then decreased during migration. 

 The time of initial ridge development varied according to position along the 

 coastline. The ridge was in incipient form along southwest ranges -10+00 to 

 -8+00 during the predisposal survey (19 July 1976) . A ridge began to develop 

 northeastward in the central beach ranges -7+00 to -4+00 about 4 days later, 

 and to develop farther upcoast (ranges -3+00 to -1+00) 10 to 11 days later. 



The ridge persisted throughout the survey period (average of 55 days) . 



Overall change in the foreshore was less apparent. In general, slight 

 scour occurred in the intertidal zone, and accretion, associated with filling 

 of the landwardmost margin of the trough, occurred in the subtidal zone. 



26 



