Future wave-climate driven longshore sediment transport along the Indian coast
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Future wave-climate driven longshore sediment transport along the Indian coast Piyali Chowdhury 1,2 & Manasa Ranjan Behera 1,3 & Dominic E. Reeve 4 Received: 25 April 2019 / Accepted: 9 March 2020/ # Springer Nature B.V. 2020
Abstract
Longshore sediment transport is an important nearshore process that governs coastal erosion/accretion and in turn defines the orientation of coastlines. In this study, we assess the changes in longshore transport rates along the Indian coast due to the potential changes in wave parameters under the RCP4.5 climate scenario. The projected wave climate for two time slices, ‘near-term/present’ (2011–2040) and ‘mid-term/future’ (2041–2070) were used to investigate changes in the corresponding sediment transport rates. An empirical model accounting for major wave parameters, longshore current, resulting sediment transport and shoreline evolution was used. It was found that most of the Indian coast exhibited the same drift direction in both time slices, although changes in transport magnitude were present. To give a broad-brush characterisation of the coastline, the shoreline elements were classified as erosive, accretive or stable based on the comparative longshore transport rates of neighbouring elements. Similar characterisations, carried out for both time slices, showed that about 35% of the total coastline would remain unaffected due to the changing wave climate in the future (i.e. there is little to no change); about 20% is expected to ‘worsen’ (i.e. expected to undergo higher magnitudes of erosion wrt present rate) and 45% to ‘improve’ (i.e. expected to accrete/reach stability). It was also observed that the net annual transport rates pertaining to the future period are not expected to change significantly with respect to the current scenario. This indicates that the change in longshore transport rates arising from future changes in wave climate as represented by the RCP4.5 climate change scenario will have a broadly neutral effect. Keywords Climate change . Wave climate . Longshore sediment transport . Coastal vulnerability . Indian coast
* Piyali Chowdhury [email protected] Extended author information available on the last page of the article
Climatic Change
1 Introduction Coastal communities are expected to be under potential threat due to changes in wave climate (Zsamboky et al. 2011; Nicholls et al. 2018). These variations are expected to impact the coastal processes, such as sediment transport. The impact of global climate change on nearshore wave climate and consequently on various coastal processes, like inundation, erosion, accretion, sediment transport, amongst others, has been widely reported from all over the world. For example, Zacharioudaki and Reeve (2011) studied the impact of future waves along central coasts of England; Almar et al. (2015) investigated the long-term effects of wave climate variations on sediment transport along West Africa; Dastgheib et al. (2016) studied the variations in future wave climate and its impact on Vietnam coast and Chowdhury and
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