Post-monsoon equilibrium beach profiles and longshore sediment transport rates at Candolim, Miramar and Keri beaches of Goa, India

Abstract

Equilibrium profile is one of the conce pts in coastal geomorphology which is a result of the balance of destructive versus constructive forces. Two e quilibrium be ach profile models, viz. Bruun/Dean’s twothirds power mode l and modified Bodge expone ntial model were used to analyse the measured post-monsoon (winter) beach profiles from three beaches in Goa having varying coastal morphology settings. The major factors that affect the equilibrium beach profile, viz. the me dian grain size (D50) and the profile shape factor m, which are inve rsely proportional to each othe r, have been analysed for their application to the study site. Also, the variation of these two parameters with beach slope and grain size is studie d. Longshore sedime nt transport rates (LSTRs) are estimate d at these three beaches from the littoral environme ntal observations. LSTRs show that during winte r months, the net transport is of the orde r of 10.83  10 6 m 3 /year (southe rly transport) and 9.02  10 6 m 3 /year (southerly transport) respectively, at Candolim and Ke ri beaches, whe reas it is about 0.62  10 6 m 3 /year (northerly transport) at Miramar. This article discusses the methods used and results of measure me nts of beach morphology, LSTRs, analysis of equilibrium profiles and influe nce of various paramete rs relate d to equilibrium profiles.