The Role of Local Geomorphology Influencing Coastal Response to Sea Level Rise

• Published in: Journal of coastal research Vol. 85; no. sp1; pp. 311 - 315
• Main Authors: Olsen, Walkiria S, Figueiredo, Salette A, Albuquerque, Miguel da Guia, Calliari, Lauro J
• Format: Journal Article
• Language: English
• Published: Fort Lauderdale Coastal Education and Research Foundation 01-05-2018; COASTAL EDUCATION & RESEARCH FOUNDATION, INC. [CERF]; Allen Press Inc
• Subjects: Beaches; Climate change; Coastal morphology; Coastal plains; Coasts; Computer simulation; Creeks; Data analysis; Data processing; dune; DUNES, BEACHES AND COASTS; Erosion; Geomorphology; Mean sea level; model simulation; Morphology; Sea level; Sea level rise; Sediment; sediment budget; Sediments; Substrates; Topography (geology); Washout; Brazil; Rio Grande do Sul Brazil
• ISSN: 0749-0208; 1551-5036
• DOI: 10.2112/SI85-063.1

Olsen, W.S.; Figueiredo, S.A.; Albuquerque, M.G., and Calliari, L.J., 2018. The Role of Local Geomorphology Influencing Coastal Response to Sea Level Rise. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 311–315. Coconut Creek (Florida), ISSN 0749-0208. Considering projected climate change scenarios with accelerated rates of mean sea level rise, Cassino Beach in Southern Brazil, a wave dominated low-gradient coastal plain, is inherently at a very high risk in relation to its impacts. Additionally, the presence of small-scale creeks (washouts) can increase coastal susceptibility to erosion in two ways: (i) changing substrate morphology by lowering foredune height; (ii) displacing sediments causing a local deficit. In order to compare coastal response under sea level rise in the presence of a washout versus at well-established foredune, two independent sets of simulation experiments were designed. Simulations were executed using Random Shoreface Translation Model (RanSTM) and considered two sea level rise scenarios (RCP 2.6 and RCP 8.5) projected for the year 2030. Experiment 1 quantified the effects of washouts channels presence (changes in morphology + sediment deficit), compared to its absence (foredune) while experiment 2 focused on isolating the effects of changes on substrate morphology from sediment budget. The results showed higher mean coastal retreat for washout substrate compared to foredune. Further data analysis indicated that changes in sediment budget, due to washout presence, exerted higher control under total coastal retreat compared to onshore topography differences in both scenarios.