A field experiment was carried at Culatra Beach in Algarve (Southern Portugal) to determine longshore transport rates and sand mixing depth on a steep (slope 0.11) meso-tidal beach. The experiment was undertaken over one and a half tidal cycles using sand tracers in conjunction with wave and current monitoring. Variation of mean significant wave height during the experiment was limited (0.34-0.37 m) with mean zero-up crossing periods of 5.1-5.8 sec. Mean longshore current velocities in the breaker zone reached a peak in the second tide (0.28 m sec-1), while they were one order of magnitude smaller during the first (0.02 m sec-1) and third tide (0.04 m sec-1). The increase in current speed was due to a moderate wind that was blowing along shore during the second tide. Average advection velocity of the tracer cloud and longshore currents showed a good correlation, leading to calculation of much larger transport rates for the second tide (1.38 x 10-2 m3 sec-) than for the other two (0.23 ...
Field Measurements of Longshore Sand Transport and Control Processes on a Steep Meso-Tidal Beach
Ciavola P.;
1997
Abstract
A field experiment was carried at Culatra Beach in Algarve (Southern Portugal) to determine longshore transport rates and sand mixing depth on a steep (slope 0.11) meso-tidal beach. The experiment was undertaken over one and a half tidal cycles using sand tracers in conjunction with wave and current monitoring. Variation of mean significant wave height during the experiment was limited (0.34-0.37 m) with mean zero-up crossing periods of 5.1-5.8 sec. Mean longshore current velocities in the breaker zone reached a peak in the second tide (0.28 m sec-1), while they were one order of magnitude smaller during the first (0.02 m sec-1) and third tide (0.04 m sec-1). The increase in current speed was due to a moderate wind that was blowing along shore during the second tide. Average advection velocity of the tracer cloud and longshore currents showed a good correlation, leading to calculation of much larger transport rates for the second tide (1.38 x 10-2 m3 sec-) than for the other two (0.23 ...I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
