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The prediction of coastal sediment transport and rate of change of shorelines into the future are traditionally done by analysis of historical satellite imageries and field observations or by empirical/numerical modeling. The modeling is traditionally done on the basis of historical data. Instead, here, we suggest the use of future conditions impacted by the climate change for this purpose and a procedure based on regional climate models. Further, considering the difficulty at some places to acquire a large amount of data of various parameters to run a numerical model, we propose the use of simple neural network as an alternative. The location studied belongs to the shoreline adjoining the estuary of River Gangavali, along the central west coast of India. Waves were simulated using a numerical wave model for past and future time periods of 36 years each, and a numerical coastal evolution model was run with this input. It was found that in future, the wave activity at this site would intensify along with certain shift in the direction of wave attack. This will push the net and gross sediment transports up by 131.7% and 114.3%, respectively, and also enhance the shoreline change rate. It was noticed that the future shifts in the wave direction could be as influential as those in the wave height and can cause more accretion of the shoreline. The study emphasizes the importance of considering the projected climate over the past one in planning a regional coastal ecosystem.

The estimation of shoreline change as well as sediment transport at a specified site can be reliably made with the help of corresponding numerical models that are run with the help of historical wave data generated using windwave models based on the input of past wind conditions. It is well known that the magnitude and behavior of historical wind and waves would not remain same in future as a result of the climate change induced by global warming. (Komar et al., 2010). In this light the present study attempts to understand what happens if future wind and waves are generated using regional climate models (RCMs) and the shoreline change and sediment transport is determined on that basis instead of historical wind and wave data. Toward this we have considered there different types of shorelines, namely (a) an uninterrupted coastal stretch, (b) the coast interrupted by an artificial structure and (c) the coast interrupted by natural features. This study goes beyond an earlier one (Rajasree et al., 2016) in which only case (a) was discussed and where coastal vulnerability was not assessed.

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