1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
0
5
10
15
20
Cross-shore Location (m)
0.6
average
upper envelope
lower envelope
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
0
5
10
15
20
Cross-shore Location (m)
Figure 84. Alongshore variation in beach profile shape for the plunging-breaker
case (in upper panel, still-water level is at an elevation of 0.9 m)
"Y..." locations listed in the legend indicate the alongshore coordinate, in
meters. Most process measurements (waves, currents, and sediment
concentration) were made in the region where the beach had the highest degree
of alongshore uniformity, between alongshore coordinates of 15 and 30 m. In
this region, the degree of alongshore uniformity in terms of these hydrodynamic
parameters is good, and comparable to that which was achieved for the fixed-bed,
concrete-beach experiments.
Significant wave heights generally varied within the range of plus or minus
10 percent of the mean values computed using data from all transects.
Variability is greatest in the incipient breaking zone. Significant wave height
along one of the transects was noticeably different for the plunging-breaker case.
Otherwise, a similar degree of longshore variability was observed in both spilling
and plunging wave cases. Variability was higher for the plunging-breaker case in
141
Chapter 10
Longshore Sediment Transport Experiments
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