A geomorphological and hydrodynamic approach for beach safety and sea bathing risk estimation

Coastal areas represent one of the most important economic driving forces for entire countries. In the last decades, along coastal areas it has been observed a marked increase in risk of bathing due to the advent of mass tourism, particularly during the summer season. Local and global reports on bathing-related incidents highlight the importance of beach safety in coastal management. This paper describes a cost-effective and semi-quantitative approach for beach safety and sea bathing risk estimation. The methodology was applied to a coastal stretch located in eastern Liguria (north western Italy, Ligurian Sea), which is characterized by high tourism vocation and can be considered indicative of some main features of Mediterranean shores. The peculiar geomorphological and hydrodynamic hazard descriptors and the beach accessibility (i.e., the exposure of bathers to hazard) of the study area have been evaluated by means of open source archive information, field surveys and expert judgement. Subsequently, probability theory was used to estimate the Hazard Index and the Risk of Bathing Index. The resulting zoning maps show that beach safety and risk of bathing do not have a uniform distribution along this coastal sector since both hazard and risk conditioning variables can frequently change from one site to another. Considering the large and rapidly expanding tourism activities in coastal environments, the obtained zoning maps reveal that the proposed method can be a flexible and simple tool for stakeholders in charge of coastal management. The proposed approach may be also adapted to other coastal-type environments by means of an accurate identification of hazard and beach accessibility descriptors that better characterise the stretch of coast under consideration.