Wave refraction and littoral currents off Colva Beach, Goa

Abstract

Wave refraction studies have been carried out for waves of different periods approaching the coast at Colva, with directions of approach lying between180 degrees and 340 degrees, to obtain a qualitative picture of littoral flows along the beach. The refraction function evaluated at an approximate depth of 4 m, indicates amplification of wave height at certain parts of the coast as the wave period increases. The wave heights are relatively lower for waves approaching from WNW and SW compared to those for waves approaching from WSW and W. The littoral flow is towards the north for deep water waves approaching from SW and towards the south for waves approaching from WNW. The studies show that waves approaching from W and WSW generate onshore - offshore flows and converging and diverging alongshore flows, giving rise to circulation cells in the nearshore regions. The effect of wave refraction pattern and the associated littoral flows on the morphology of the beach has been discussed.