Impact of Transversal and Longitudinal Sediment Transport on the Shoreline Evolution: Effects of Sandbar Volume and Wave Climate

Ferreira, A.M., Coelho, C., and Silva, P.A., 2024. Impact of transversal and longitudinal sediment transport on the shoreline evolution: Effects of sandbar volume and wave climate. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 619-623. Charlotte (North Carolina), ISSN 0749-0208. The evolution of artificial nourishments and its impacts in beach morphology depends on the sediment dynamics. Numerical modeling has potential to support such analysis and to better understand the benefits of such interventions, also supporting decision-making. The analyses of beach nourishment interventions must consider both cross-shore (transversal) and longshore (longitudinal) processes of sediment transport. Therefore, a numerical study was conducted to enhance the modeling capacity of nourishment interventions from a medium to long-term perspective integrating cross-shore and longshore sediment transport processes. Different conceptual scenarios discussing wave climate parameters and longshore sediment transport potential capacity on beach morphodynamics. The results suggest that under a constant wave climate, cross-shore sediment transport processes drive beach profiles toward equilibrium. Varying sandbar volumes alongshore induce potential sediment transport gradients, allowing access to the benefits of nourished sediments within the numerical domain. The final shoreline position results from the balance between cross-shore and longshore processes. Overall, the developed model is useful for studying nearshore nourishments in relation to wave climate, sandbar equilibrium volumes, sediment transport, and their longshore gradients. This knowledge is valuable for supporting coastal management, particularly in investigating nearshore nourishments.