Application of longshore transport equations to the Andhra coast, east coast of India

Abstract

Ship-reported waves published in the Indian Daily Weather Report are compiled for a period of 16 years and are used for the estimation of the longshore transport rate. Using the two well known longshore transport equations, viz., the Shore Protection Manual equation and the Komar and Inman equation, the longshore transport rate at Visakhapatnam beach is computed and the values are compared with earlier studies. Based on the inference that the Shore Protection Manual equation yields a better estimate for this region, the same equation is used for the estimation of the longshore transport rate along the Andhra coast. This study shows that the general direction of longshore transport is towards northeast during March to October and southwest during November to February. The longshore transport rate is high during the southwest monsoon period from June to September. A higher sediment transport rate is observed for the coastline oriented at 80 degrees east of north. The annual net transport is found to be quite low at the coastal segments near Ramaypatnam, Machilipatnam and Sacremento Light House, whereas it is found to be high near Nizampatnam, Gollapalem and Narasapur.