Disentangling the human influence on droughts in semi-arid regions: A socio-hydrological approach

Droughts are not just a problem of lack of water but are complex and multi-layered societal problems, triggered by hydro-meteorological drivers and influenced by human activities. The societal component of drought plays a relevant role in the magnitude of the impact since the coping and adaptation measures for droughts vary widely among societies around the world. Therefore, it is crucial to analyze drought events considering not only the physical component (hydro-meteorological variables) but also the human influence on hydrological systems. In this study, we aim to disentangle the human influence on the evolution and intensification of drought events through the use of an agent-based socio-hydrological model. The case study is the Quixeramobim region located in the semi-arid region of northeastern Brazil that is often affected by drought and water shortages. Through field interviews with farmers and stakeholders, we identified the main sources of water available in the region, as well the way in which they are used and prioritized, and the basic operating rules of the public reservoirs. The study area features two public reservoirs that are operated by local water resource agencies, thousands of private reservoirs (owned by farmers) that are built informally, and have no regulation. This information was translated into algorithms and is now implemented as an Agent-Based Model (ABM) through the NetLogo software. Furthermore, the hydro-meteorological forcings will be simulated considering the mesoscale semi-distributed hydrological model for semi-arid regions (WASA) and will be used as input data in the NetLogo ABM framework. At the end, we expect to present a socio-hydrological model capable of accessing human influences on the intensification and propagation of drought events.