Managing physical and anthropogenic hazards on macrotidal Amazon beaches

• Tide-dominated forces result in stronger flooding tidal speeds.
• Higher wind-waves represent the major hazard to beachgoers.
• The probability of the risks is increased during vacation periods.
• Coastal management actions can avoid accidents and conflicts.

Equatorial sandy beaches have considerable tourism potential, while morphological studies, which are indispensable for the development of effective beach management strategies, are scarce. This paper analyses beach processes, morphodynamic state and change, and associated physical hazards and risks, in relation to spatial and temporal oscillations in meteorological and hydrodynamic variables on several macro-tidal Amazon coast sandy beaches. These beaches are located in macrotidal areas with tide ranges between 4 and 6 m and exposed to waves with Hs up to 1.5 m. In addition, they are characterized by low gradients, fine sand and an intertidal width of 200–400 m at low spring tide. Because of the tidal modulation the beaches transform from wide bare tidal flats to rapidly inundating flats with increasing wave and tidal currents velocities and wave height, as the tide rises. These conditions trap beach users and their vehicles leading to numerous accidents and some fatalities. In addition a range of beach and water activities (vehicles, kite and wind surfing) bring users into conflict and risk. At present coastal and beach management plans are non-existent. There is an urgent need to implement beach management practices which allocate beach usage, educate and warn beach users of the hazards, provide first aid and to employ lifeguards to maintain beach safety, enforce areas of usage and effect rescues, particularly during the vacation periods.