Author(s): Manuel Cobos; Andres Payo; Dave Favis-Mortlock; Helen F. Burke; Dave Morgan; Gareth Jenkins; Helen Smith; Thomas J. Fletcher; Pedro Otinar; Pedro Magana; Asuncion Baquerizo

Linked Author(s): Manuel Cobos, Pedro Magaña

Keywords: Coastal erosion; Sediment layers; Sediment sources

Abstract: Coastal regions contain a variety of morphological landforms such as beaches, cliffs, and dunes, among others, with a very heterogeneous sediment composition. Their evolution in a medium and long-term basis strongly depends on the availability of sediment and its disposition in layers composed of different materials that can be loose or consolidated. This fact makes it very difficult to adequately represent the transport processes and to make predictions about their morphodynamics (Moser et al., 2012). The present study is based on the so-called Coastal Modelling Environment, CoastalME, (Payo et al., 2015), a framework that integrates the essential characteristics of landform-specific models using a common spatial representation within an appropriate software. The model includes the possibility of long-term cliff erosion, or shore-platform erosion which transform the consolidated sediments into available loose material which can be transported during storm events. In the more recent version, point or line specific sediment sources like as those associated to river discharges, dry riverbed or creeks were considered. The model is applied to different landforms with the settings implemented for Andalucía that contain (1) the geological substrate thickness model that considers not only the type of material, the average grain sediment size, but also discretizes the substrate into layers of different thickness and sediment solid states (e.g. loose and consolidated); (2) the presence of boardwalks, ports, buildings, and roads and (3) the sediment supply from ramblas (e.g. most of the time dry riverbeds but during heavy rainfall events when the supply non negligible amount of material to the coast). Its performance is analyzed in comparison with the model without those components, that is, run with the commonly general assumptions - homogeneous and infinitely thick sediment layer without sources of sediment supplies - and its ability to make medium- and long-term predictions of the evolution of the coast. References •Moser, S. C., Jeffress Williams, S., & Boesch, D. F. (2012). Wicked challenges at Land’s End: Managing coastal vulnerability under climate change. Annual Review of Environment and Resources, 37, 51-78. •Payo, A., Favis-Mortlock, D., Dickson, M., Hall, J. W., Hurst, M. D., Walkden, M. J., AIan Townend, Matthew C. Ives, Robert J. Nicholls, and Michael A. Ellis. (2017). Coastal Modelling Environment version 1.0: a framework for integrating landform-specific component models in order to simulate decadal to centennial morphological changes on complex coasts. Geoscientific Model Development, 10(7), 2715-2740.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221204

Year: 2022