Modelling the Human-Flood Interactions : Effects of different societal risk perceptions on flood losses

Abstract: Can one society’s flood risk perception and management strategy impact the neighbouring society? This study applies a socio-hydrological model to four ideal types of society living along the same river. These societies have various rationalities and risk perceptions: risk-controlling, risk-monitoring, risk- neglecting and risk-downplaying. Combined with a hydraulic model of the river, this study explores the human-flood interactions and how the four societies can influence each other. The results show that the society that adopts soft-measures experiences the lowest flood loss; the society that neglects flood risks suffers from much higher flood losses. Dynamics, including the levee effect and adaptation effect, can also be observed. The society that builds levees to alter the hydrological regime causes the flood stage to be higher than it would have been without levees, indirectly increasing flood loss for the neighbouring societies. A more sustainable flood risk management strategy calls for broader considerations than the conventional method.