First Tidal run D1

Test D1 (Series D1: lagoon 2.5m; tide 1.75-3.25m; Hs=0.8m; Tp=4.5s; ARC off)
This test is the first of a series of three with a 1.5-m tide. In hindsight the duration of the tidal cycle was too short (75 min from low to high tide) and the pumps were not able to keep up with the planned rate of tidal rise. A different tidal duration (90 min from low to high tide) will be used for the next three tidal runs. The initial profile was obtained by exposing the end profile of test C4 to 3 min of long period waves (Tp = 10 s) with the water level at 2.5 m. These conditions effectively removed the berm, leaving a relatively featureless slightly convex profile. During the rising tide, the berm build-up and a step developed just below high tide level. The falling tide left the berm stranded and the step migrated down the beach. The contourplots show better the temporal evolution of the beach profile. Of interest is the tidal asymmetry: (1) berm accretion mainly during the rising tide; (2) step development mainly on the falling tide.

Thanks to Prof Hoff for preparing this figure