Longshore Currents on a Meso-Tidal Beach of Goa, India - Measurements and Improved Formulae

Field experiments in the surfzone were conducted on a meso-tidal beach stretch between Sinquerim and Baga off Goa on India's central west coast. Surfzone waves and currents were measured using an array of seabird wave and tide gauges and Aanderaa RCM9 current meters. Rip currents were observed prominently in this stretch with increased intensity during the ebb tide. Six longshore current prediction equations are tested for their suitability in this region. The Longshore Current (LSC) estimated using these equations showed a wide range of Mean Absolute Percentage Error (MAPE) and Scatter Index, and the correlation coefficients were also found to be less than 50 %. Hence, these equations are further modified by including the alongshore wind shear component, and the LSC was re-estimated to study the variations in current along the Candolim beach. It was observed that the correlation coefficients improved up to 64 % for most of the equations.