Rethinking risk on rocky coasts: moving towards integrated physical and social hazard analysis

Rocky coasts are hazardous environments accounting for 19% of all coastal drowning fatalities in Australia from 2004 - 2014 (Surf Life Saving Australia, 2014). In most cases, drowning fatalities are thought to result from waves washing over platforms, which sweep unsuspecting victims into the sea. Morphological elements of the shoreline, namely platform elevation, the slope of platforms, and the depth of water off the seaward edge, have been shown to be key elements for understanding the likelihood of wave overtopping: termed Morphological Exposure (Me) (Kennedy et al., 2013). However, little is known about what features of the rocky coast are perceived as being hazardous. This gap is an obstacle to understanding complex behavior in human-environmental systems as well as the interactions between humans with place, which are more complex than physical assessments are able to capture. The focus of this project is to address this gap by integrating the physical risk of wave overtopping (Me) and socially perceived risk with the aim of generating a holistic understanding of hazards on shore platforms. This can be used to promote safe decision making and behavior in risky situations and reduce the likelihood of drowning fatalities on rocky coasts. Perceived risk data was collected via an online self-completion questionnaire from Surf Life Saving Australia (SLSA) volunteers. SLSA was chosen by virtue of its direct experience with the hazards under investigation. This experience permits communication of site-specific expertise on risk, in addition to an acute understanding of capabilities in the context of risk on rocky coasts. All SLSA volunteers whose surf club is within 1km of a rocky coast in Victoria, Australia received the questionnaire. Mixed methods are used to generate data from competing epistemological and ontological assumptions of risk. The aim is to compare and analyse if physical and social risk possess similar trends in rating the threat of drowning risk. Three geotagged photos of varying platform morphologies were taken and assigned a physical risk value (Me) using airborne LiDAR. Respondents were experienced lifesavers, with 33% having been a lifesaver for >15 years and only 5% < 1 year. SLSA volunteers used a Likert scale to rate the perceived risk in each photo. Results show there is a statistical difference between perceived risk ratings among the geotagged photos, showing changes in risk perceptions between contexts. Me and risk perception ratings are on different risk scales, however, their magnitude ratings of the threat of drowning follows a similar pattern. Additionally, each respondent identified specific hazards in each photo. The most frequent hazard (29% of all responses) identified was slipping. Upon further investigation, slipping hazards are perceived as the greatest risk on shore platforms, particularly when waves are not breaking on platforms. In addition to Me, slipping can be used as a proxy for quantifying and communicating site-specific risk in hazardous rocky coast environments. This project contributes new risk knowledge to the development of a rocky coast hazard framework and demonstrates a methodology for improved understanding of complex human-environmental interactions through integrating physical and social measures of risk