Modeling the interplay between droughts, floods and human activities

Several studies showed an increasingly negative impact of droughts and floods due to the combined effects of socio-economic and climatic factors. To better understand changes in hydrological risk over time, it is fundamental to unravel the complex interactions between increasing urbanization, population growth, water management strategies and increasing frequency and intensity of hydrological hazards. To this end, various socio-hydrological models have been developed over the past decade to explain the dynamics of risk generated by either human-flood or human-drought interactions. This study proposes a new analytical framework to represent, for the first time, the deeply intertwined interactions between humans and both hydrological extremes, i.e. floods and droughts. A new system dynamic model is developed and then applied to explore the phenomena generated by human-water interactions in relation to different water management strategies. The results show the ability of the proposed model to capture multiple socio-hydrological phenomena that have been empirically observed (levee effect, supply-demand cycle, reservoir, rebound, and sequence effects). In particular, our model is capable to capture dynamics that did not emerge in previous socio-hydrological models where human, drought and flood interplay is considered independently. Given its explanatory value, the model can contribute to a better interpretation of changes in drought and flood risk associated with anthropogenic influences.