Assessment of island beach erosion due to sea level rise: The case of
the Aegean Archipelago (Eastern Mediterranean)
Isavela N. Monioudi1, Adonis F. Velegrakis1, Antonis E. Chatzipavlis1, Anastasios Rigos1,2, Theophanis Karambas3, Michalis I. Vousdoukas4,1, Thomas Hasiotis1, Nikoletta Koukourouvli5, Pascal Peduzzi6, Eva Manoutsoglou1, Serafim E. Poulos7, and Michael B. Collins81Department of Marine Sciences, University of the Aegean, University Hill, Mytilene, GR-81100, Greece 2Department of Cultural Technology and Communication, University of the Aegean, University Hill, Mytilene GR-81100, Greece 3Department of Civil Engineering, Aristotle University of Thessaloniki, University Campus, GR-54124 Thessaloniki, Greece 4European Commission, Joint Research Centre (JRC), Directorate for Space, Security & Migration, Disaster Risk Management Unit, Via E. Fermi 2749, Ispra (VA), I-21027, Italy 5Department of Geography, University of the Aegean, University Hill, GR-81100 Mytilene, Greece 6UNEP/DEWA/GRID-Geneva, International Environment House, 11 Chemin des Anemo nes, CH-1219 Chatelaine, Switzerland 7Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Panepistimioupoli Zografou, 15784 Athens, Greece 8Plentziako Itsas Estazioa, University of the Basque Country, Areatza z/g. E-48620, Plentzia-Bizkaia, Spain
Received: 17 Oct 2016 – Accepted for review: 03 Nov 2016 – Discussion started: 07 Nov 2016
Abstract. The present contribution constitutes the first comprehensive attempt to (a) record the spatial characteristics of the beaches of the Aegean Archipelago (Greece), a critical resource for both the local and national economy; and (b) provide a rapid assessment of the impacts of the long-term and episodic sea level rise (SLR), under different scenarios. Spatial information and other attributes (e.g. presence of coastal protection works and backshore development) of the beaches of the 58 largest islands of the Archipelago were obtained on the basis of remote-sensed images available in the web. Ranges of SLR-induced beach retreats under different morphological, sedimentological and hydrodynamic forcing and SLR scenarios were estimated, using suitable ensembles of cross-shore (1-D) morphodynamic models. These ranges, combined with empirically-derived estimations of wave run up-induced flooding, were then compared with the recorded maximum beach widths, to provide ranges of retreat/erosion and flooding at the Archipelago scale. The spatial information shows that the Aegean beaches may be particularly vulnerable to mean (MSLR) and episodic SLRs due to: (i) their narrow widths (about 59 % of the beaches have maximum widths < 20 m); (ii) their limited terrestrial sediment supply; (iii) the substantial coastal development and (iv) the limited existing coastal protection. Modeling results indeed project severe impacts under mean and episodic SLRs, which by 2100 could be devastating. For example, under MSLR of 0.5 m (RCP4.5), a storm-induced sea level rise of 0.6 m is projected to result in complete erosion of between 31 and 88 % of all beaches (29–87 % of beaches currently fronting coastal infrastructure and assets), at least temporarily. It appears that, in addition to the significant effort and financial resources required to protect/maintain the critical economic resource of the Aegean Archipelago, appropriate coastal "set-back zone" policies should be adopted and implemented.
Monioudi, I. N., Velegrakis, A. F., Chatzipavlis, A. E., Rigos, A., Karambas, T., Vousdoukas, M. I., Hasiotis, T., Koukourouvli, N., Peduzzi, P., Manoutsoglou, E., Poulos, S. E., and Collins, M. B.: Assessment of island beach erosion due to sea level rise: The case of
the Aegean Archipelago (Eastern Mediterranean), Nat. Hazards Earth Syst. Sci. Discuss., doi:10.5194/nhess-2016-336, in review, 2016.