A dynamic socio-hydrology model for the assessment of time-variant feedbacks between irrigators’ adaptive responses and basin hydrology

Abstract. This study introduces a Dynamic Feedback (DF) socio-hydrology model that couples the widely used SWAT hydrological model with a microeconomic model of irrigators’ behavior (Positive Multi-Attribute Utility Programming Model). Unlike conventional static or exogenous scenario-based socio-hydrology couplings, the DF setup allows irrigators’ adaptive responses and basin hydrology to interact dynamically through time-variant two-way endogenous exchanges. The model is illustrated with an application to the Tormes catchment in Spain, where we assess the impacts of a Drought Management Plan (DMP) that introduces water caps to ensure environmental flows under alternative climate change scenarios (SSP126 and SSP585), using both a DF and no-feedback setup. Aggregate results indicate relatively small differences between the DF and no-feedback setup in annual hydrological indicators across the Tormes catchment (<0.5 %). Critically, differences become significant at sub-basin and seasonal scales, where adaptive irrigators’ responses to DMP caps during dry years in the DF setup increase summer inflows by up to 9.3 % under SSP585 as compared to the no-feedback setup, signaling higher effectiveness of DMP interventions.