How do climate and land use changes affect the water cycle? Modelling study including future drought events prediction using reliable drought indices

Abstract

To investigate the impacts of climate and land use changes on hydrology, the Don catchment in Yorkshire, UK, was selected. A physically based distributed catchment-scale (DiCaSM) model was applied. The model simulates surface runoff, groundwater recharge and drought indicators such as soil moisture deficit SMD, wetness index WI and reconnaissance drought index RDI. The model's goodness of fit using the Nash–Sutcliffe efficiency factor was >91% for the calibration period (2011–2012) and 83% for the validation period(1966–2012). Under different climate change scenarios, the greatest decrease in stream flow and groundwater recharge was projected under medium- and high-emission scenarios. Climate change scenarios projected an increase in evapotranspiration and SMD, especially in the latter half of the current century. Increasing the woodland area had the most significant impact, reducing stream flow by 17% and groundwater recharge by 22%. Urbanization could lead to increase in stream flow and groundwater recharge. The climate change impact on stream flow and groundwater recharge was more significant than land use change. Drought indices SMD, WI and RDI projected an increase in the severity and frequency of drought events under future climatic change, especially under high-emission scenarios.