Risk management of coastal water safety for recreational activities: The case of Taoyuan coast

To reduce drowning fatalities and health damage during recreational activities in coastal waters, this paper proposes a dynamic risk management system. Based on the operational definition of risk management, potential risks of coastal recreational activities are first identified as surfzone hydrodynamic and water quality. The safety criteria for each factor are discussed accordingly. The depth-velocity product is adopted to evaluate hydrodynamic safety. Salinity is adopted as a proxy indicator, which could be monitored in real-time, of Escherichia coli colonies in order to avoid the 18–24 h delay for cultivation. Then, technologies for surfzone hydrodynamic and water quality monitoring are developed and implemented as the basis for real-time risk assessment. This system is tested on the north-western coast of Taiwan. The results are discussed as a case study. The results from drifter cluster and miniature wave buoy for mapping the current and waves demonstrates a rotating eddy induced by tidal current. The range of safe water areas could be clearly marked. By applying this dynamic risk management system for coastal recreational activities, an early alert can be provided with the hope to reduce drowning.