A horizontal line in Figure 7(b) represents no change in contour posi- 

 tion. An upward-sloping line indicates landward movement of contour posi- 

 tion (i.e., erosion); a downward- sloping line indicates deposition. The 

 slope of a line indicates the horizontal rate of erosion or deposition at 

 that elevation. The three x's at time t2 (Fig. 7,b) indicate multiple 

 contour positions at elevation -0.2 which is shown by the intersection of 

 the dashline with profile t2 in Figure 7(a). 



Three types of contour movement plots included in this study are: 



(a) The seawardmost intercepts along one range for any 

 or all depths; 



(b) the seawardmost intercepts for one depth along all 

 ranges; and 



(c) all contour intercepts along one range, for up to 

 12 selected depths. 



The coordinate system used for the contour movement plots is shown in 

 Figure 8. 



The following elevations are referred to in the discussion that follows; 

 ±0.2 foot (±6.1 centimeters), -0.3 foot (-9.1 centimeters), -0.4 foot 

 (-12.2 centimeters), -0.5 foot (-15.2 centimeters), -0.6 foot (-18.3 centi- 

 meters), -0.7 foot (-21.3 centimeters), -0.8 foot (-24.4 centimeters), 

 -0.9 foot (-27.4 centimeters), -1.0 foot (-30.5 centimeters), -1.1 feet 

 (-33.5 centimeters), -1.2 feet (-36.6 centimeters), -1.3 feet (-39.6 centi- 

 meters), -1.4 feet (-42.7 centimeters), -1.5 feet (-45.7 centimeters), 

 -1.6 feet (-48.8 centimeters), -2.0 feet (-61.0 centimeters), and -2.1 

 feet (-64.0 centimeters). 



b. Profile Zones . Definitions of coastal engineering terms used in 

 LEBS reports conform to Allen (1972) and U.S. Army, Corps of Engineers, 

 Coastal Engineering Research Center (1975). However, the boundary between 

 the foreshore and inshore zones is defined in these reports as the lower 

 limit of backrush (low water line) and is at elevation -0.2 foot. 



The seaward edge of the inshore zone is defined as extending from the 

 low water line through the breaker zone. The boundary between the inshore 

 and offshore zones is at elevation -0.8 foot. 



A definition sketch of the profile zones is shown in Figure 9. The 

 profile in each experiment developed in a similar sequence. Early pro- 

 files (broken line in Fig. 9) had a steep foreshore, a short inshore zone 

 with a longshore bar, and a gently sloping offshore zone. Later profiles 

 (dashline in Fig. 9) also had a steep foreshore zone, but the inshore zone 

 widened to a long, flat shelf which terminated in a relatively steep off- 

 shore zone. This development is shown by contour movement plots (Figs. 

 10 to 17) of the seawardmost contour intercepts for elevations at 0.1- 

 foot-depth increments from +0.2 to -2.1 feet. Figures 10 to 12 are for 



29 



