Current speed and direction forced by the fair-weather wave is shown in Fig. 5. Wave
shoaling, refraction, and breaking on the ebb shoal generate complex and strong currents there
reaching 1.2 m/s. The surf zone is approximately 100 m wide and north-directed currents of
1.1 m/s are calculated there as a result of the wave forcing.
B
A
Speed
Speed
m/s
Fig. 5. Current speed and direction, fair-weather wave
Case 3: Storm Wave
Wave height and direction for the storm wave case are shown in Fig. 6. Strong refraction,
wave shoaling, and breaking occur at and near the ebb shoal. Wave height ranges from 3 m at
the seaward boundary to 3.5 m on the outer edge of the ebb shoal. Asymmetrical breaking takes
place around the ebb shoal with waves breaking further seaward north of the shoal as compared
to south of it.
Current speed and direction are shown in Fig. 7. The surf zone extends from the beach to
approximately 250 m seaward, shifting the maximum longshore current speed away from the
beach, as compared to the fair-weather wave case. Breaking waves on the ebb shoal produce
strong northward flow over the central shoal area, and southward flow around the outer
perimeter. In addition, a rip current forms off of the south jetty.
Militello and Kraus
6
Previous Page
