Since the early 1950s, Greece has been a popular travel destination providing high-quality tourism services. This was amplified by its diverse landscape, extended sandy beaches, scattered archaeological sites, people’s mentality, and adequate infrastructure. In particular, the south Aegean Archipelago attracts more than six million (6,000,000) visitors annually, approximately 27% of tourist arrivals in Greece. The carrying capacity assessment of the South Aegean region aims to improve the already high standards of the offered tourist services. Seventeen appropriate variables were analyzed to assess and increase tourism attractiveness by alternative products for long-term and sustainable management. Furthermore, the outcomes of the carrying capacity indicators application provide specialized solutions to control the over-tourism impact, mitigate the natural environmental degradation, and establish a roadmap for sustainable development in the study area. The required data were interpreted based on the PAP/RAC 1997 and WTO, enriched with more suitable variables from national and international literature to determine the carrying capacity. Therefore, the selection of seventeen (17) most representative indicators was unavoidable. Finally, the calculation of the different indexes showed that Mykonos and Thira are far above the indicator scale limits and are facing over-tourism issues. Additionally, the numbers of tourists concentrated in the abovementioned islands may accelerate the environmental degradation and, as a result, the tourist product will be downgraded. The set of these seventeen indicators works best since low, obfuscated, or no environmental data are available for the South Aegean region from the official state agency. Alternative tourist development and the extension of the tourist season based on local climatic conditions must be applied to ease the over-concentration and, consequently, the degradation of the tourist product. The large islands do not seem to face significant problems. However, the calculation of CCA will contribute to the decongestion of tourism concentration together with environmental decompression, leading to sustainable development in the South Aegean region.

The foreseeable acceleration of global sea level rise could potentially pose a major threat to the natural charm and functional integrity of the world-renowned tourist coastal attractions of Rhodes Island, as a result of the anticipated increasing frequency of flooding and erosion events. Hence, this study aims to determine the most vulnerable segments (in terms of physical impact) of the Rhodes coastline through the widely accepted coastal vulnerability index (CVI), applying a combination of well-known, broadly used approaches and methods. The frequency distribution of the current CVI along the island’s coastline suggests a rather worrying high to very high vulnerability of 40%. In addition, a CVI projection to the end of the 21st century (based on the Intergovernmental Panel on Climate Change predictive scenarios) indicates an enhancement of the total vulnerability by 48%, mainly focused on the majority of the western coastline. Hence, a considerable number of popular coastal destinations in the island shall remain under unignorable threat and, therefore, coastal managers and decision-makers need to hatch an integrated plan to minimize economic and natural losses, private property damage and tourism infrastructure deterioration from flooding and erosion episodes, which will most likely be intensified in the future.

This paper presents a recently developed Operational Forecast Platform (OFP) for prevailing sea conditions at very important ports worldwide (Accu-Waves). The OFP produces reliable high-resolution predictions of wave characteristics in and around ocean ports. Its goal is to support safer navigation, predict possible port downtime, assist vessel approaching, enhance management of towing services, and bolster secure ship maneuvering in busy ports around the globe. Accu-Waves OFP is based on integrated, high-resolution wave modelling over the continental shelf and in coastal areas that incorporates data from global- and regional-scale, open-sea wave and ocean circulation forecasts as boundary conditions. The coupling, nesting, calibration, and implementation of the models are reported and discussed in this paper, concerning 50 selected areas near and inside significant port basins. The detailed setup of the Accu-Waves OFP and its sub-system services is also provided regarding three-day forecasts at three-hourly intervals. The validation of the wave forecast system against in situ observations from wave buoys in coastal areas of the USA, Belgium, and Spain, as well as other model predictions by established OFPs, seems very promising, with performance skill scores ranging from adequate to very good. An exceptional case of stormy seas under severe marine weather conditions with very high wave maxima (>10 m) in the port of Algeciras is further discussed, confirming the good performance of the Accu-Waves OFP.

The main objective of the present paper is to achieve the simulation of the long-term (e.g., annual) morphological evolution (bathymetry and shoreline) of a coastal area (Mastichari beach, Greece) due to wind-generated waves in an accurate and cost-effective way. For this purpose, wave climate schematization techniques are adopted in order to reduce the computational effort without losing or distorting the crucial information. Referring to the current practice, the wave chronology is not considered in detail in these acceleration techniques, and therefore, sea bottom and shoreline evolution are not estimated as a function of time. To fill this gap, a novel and easy-to-use chronology-based wave input reduction method is developed to produce representative wave time series of different intensities and durations. The performance of all the applied techniques in the present study is evaluated, and a comparative analysis is conducted. It is shown that the new chronology-based wave input reduction method can achieve a model run-time reduction of about 70%, while at the same time, it provides satisfactorily accurate results. In general, this research could be useful for coastal engineering studies and coastal zone monitoring, and thus, it would be a valuable tool for coastal engineers and marine scientists.