Nearshore Processes along Tikkavanipalem Beach, Visakhapatnam, India

Abstract

Directional wave data collected at 12 m water depth, at 1 km distance off Tikkavanipalem from December 1997 to November 1998, was used to estimate the longshore currents and longshore sediment transport rate considering the sea and swell waves separately using the CERC formula. Daily littoral environmental parameters were observed at 3 stations and longshore sediment transport rate was estimated using the Walton’s equation. A comparative study was carried out on theoretical and measured longshore currents. The ratio of spectral energy at first and second spectral peaks show that the energy at second peak was more than fifty percent of the energy at first peak in 35% of the data collected. The longshore current speed computed based on Longuet-Higgin's equation was about 25% more than the measured and that based on Galvin's equation was about 22% more than measured. The difference between the gross sediment transport rate estimated based on the two method is around 6%. The sediment transport using Walton's equation shows that average annual gross transport was 0.371 X 10⁶ m³ and the average annual net transport (towards northeast) was 0.173 X 10⁶ m³