b. Profile Zones. Definitions of coastal engineering terms used in 
LEBS reports conform to Allen (1972) and the Shore Protection Manual (SPM) 
(U.S. Army, Corps of Engineers, Coastal Engineering Research Center, 1975). 
For the profile zones in this study, the boundary between the foreshore 
and inshore zones, the lower limit of backrush (low water line), is at 
elevation -0.1 foot. The seaward edge of the inshore zone is defined as 
extending through the breaker zone. The boundary between the inshore and 
offshore zones for this experiment is at elevation -0.9 foot. 
A definition sketch of the profile zones is shown in Figure 6. The 
profile at 55 hours (dashline) had a very narrow foreshore zone with a 
steep beach face and a high scarp, an inshore zone consisting of two 
almost flat regions separated by a gentle slope, and a steep offshore 
zone. The profile at 140 hours (broken line) was similar. The foreshore 
and offshore zones had roughly the same shapes, but the foreshore had 
retreated landward and the offshore had prograded seaward. The inshore 
zone had a longer inner shelf, a sloping region in the same position, and 
more of a bar and trough at the outer end. This development is shown by 
contour movement plots (Figs. 7 to 11) of. the seawardmost contour inter- 
cepts for elevations at 0.1-foot: depth increments from +1.1 to -2.2 
feet. The heavier lines for the -0.1- and -0.9-foot contours distinguish 
the three profile zones in the figures. In the foreshore and offshore 
zones the contour lines are close together, indicating steeper slopes; 
in the inshore zone the lines are generally spaced farther apart, indica- 
ting flatter slopes. 
(1) Foreshore Zone. Within the first 40 minutes the foreshore zone 
developed the basic shape which it maintained throughout the experiment. 
This is indicated by the parallel lines after 40 minutes in Figure 12, 
which compares the contour movements in the foreshore zone along the 
five ranges during the first 10 hours. The foreshore maintained basic- 
ally this shape as it retreated in the erosion process (upward-sloping 
lines for -0.1 foot and higher contours in Figs. 7 to 11). 
Although contours of the foreshore moved together, the lines were 
not always parallel (Figs. 7 to 11), indicating some variation in 
foreshore slope with time at each range. Slope values at the stillwater 
level (SWL) intercept (Table 7) were determined by measuring the slope 
between survey points on either side of the shoreline. The steepest 
slope was 0.56 and the flattest slope was 0.10, indicating that although 
the slope varied, the values were all fairly steep. The average slope 
was 0.204. 
The shoreline (0 contour) movement along the five ranges is compared 
in Figure 13. After 5 hours the shoreline along the different ranges 
varied as much as 2.5 feet (0.76 meter) in position at a given time. 
This is further illustrated by the photos in Figure 14. At 50 hours 
(Fig. 14,a) the shoreline and scarp on the near side (ranges 1 and 3) were 
farther landward than the shoreline along the far side (ranges 7 and 9), 
indicating that the backshore and scarp were probably eroding along 
28) 
