Nearshore processes along north Karnataka coast

Abstract

Ten base stations were established along the shoreline between Karwar and Bhatkal and monthly beach profiles, breaking wave characteristics and longshore currents were measured for a period of one year. The lowest beach levels were observed during the southwest monsoon period except at two stations, where it was observed during northeast monsoon period. Considerable part of the beach profile regained their original profile by February at some stations and by April at the remaining stations. The beaches had undergone the seasonal erosion and were stable during the annual processes along this stretch of the coastline. The relatively stronger longshore currents in April along the entire study region infer that the waves approach the coast with more obliquity. Also it was found that the distribution of longshore currents was not similar at all stations along the study region. The annual net sediment transport was 0.069 x 10 sup(6)/year towards north at Arge beach and 0.040 x 10 sup(6) m sup(3)/year at Kasarkod and it was 0.142 x 10 sup(6) m sup(3)/year towards south at Gangavalli. The beach sediments at all stations consist less than 2% by weight the calcareous fragments and median size of the beach sediment show that the entire study region consists of fine sand with median size ranging from 0.1 to 0.25 mm.