Overwash hazard assessment
Rodrigues, B. A. (Universidade do Algarve)
Matias, A. (Universidade do Algarve)
Ferreira, Ó. (Universidade do Algarve)

Data:	2012
Resum:	Overwash is a natural storm-related process that occurs when wave runup overcomes the dune crest. Because coastlines are globally occupied, overwash is a hazardous process and there is a need to identify vulnerable areas. This study proposes a method to detect overwash-prone areas in the Ancão peninsula, Portugal, and eventually outlines a vulnerability map. Dune base (DLOW) and crest (DHIGH) topography were surveyed. Three different storm scenarios (5-, 10- and 25- year return period storms) and associated waves and sea level were determined. According to these data, extreme wave runup (RHIGH) was calculated by a parameterisation set for intermediate-reflective beaches. The maps for collision and overwash regimes were designed by comparing RHIGH values with DLOW and DHIGH. Almost the entire dune base along the peninsula is vulnerable to collision regime. The overwash process was identified mainly along the tidal inlet hazard area and within the human-occupied portion of the beach, where overwash is expected to occur within 5 years of return period. The developed method considers the main overwash driving forces and proved to identify hazardous areas previously observed in the area. Occasional differences between modelled and observed overwash areas can be attributable to equipment errors, morphology interpretation subjectivity and maladjustments in runup parameterisation. Nevertheless, the method proved to be effective in reproducing the overall Ancão peninsula vulnerability and can be widely applied. Therefore, it is a simple and potentially important tool for coastal management that enables mitigation strategies for occupied coasts and assessment of geological and ecological consequences in natural areas.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Overwash ; Storm Surge ; Runup ; Barrier Island ; GIS
Publicat a:	Geologica acta, Vol. 10, Núm. 4 (desembre 2012) , p. 427-437, ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/263678
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/105.000001743
DOI: 10.1344/105.000001743

12 p, 1.1 MB

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