Sediment transport and shoreline shifts in response to climate change at the tidal inlets of Chilika, India

Abstract

The shoreline adjoining Chilika Lake, situated along India’s east coast, has multiple tidal inlets which connect the lake with Bay of Bengal. The shoreline behavior near such inlets is generally studied with the help of a suitable numerical model. Such models are run on the basis of historical data of waves and other information. However, the waves in future may show different strength and pattern than the past as a result of the climate change induced by global warming. It is thus necessary that the model input should correspond to future or projected data of wind and waves. In this work, we have used the wind information from a state-of-the-art regional climate model, CORDEX RegCM-4, of future 25 years in order to run a shoreline evolution model and have derived the longshore sediment transport rate as well as the shoreline change rate around Chilika inlets. These future values are compared with corresponding ones of the past 25 years. It is found that at the given location, mean wind might go up by 20%, and this could raise the mean significant wave height strongly by 32%. The direction and frequency of occurrence of waves would also change, and this in turn will cause an increase in the net littoral drift by 41% and net accumulated drift over the entire cross-shore width by 84%. Interestingly, the present site where accretion was prevalent in the past may see erosion in future at the rate of about 1 m per year.