Hydrological drought characteristics and its propagation from meteorological drought in the Jing river basin under environmental change

Study region: The Jing River basin on China's Loess Plateau is an arid to semi-arid region strongly influenced by climate change and human activities. Study focus: Understanding of how human activities alter drought development and recovery mechanisms remains limited, particularly in complex and dynamic environments. We employed the Soil and Water Assessment Tool (SWAT) to simulate natural runoff in the Jing River basin, aiming to establish a baseline natural runoff model and isolate anthropogenic influences. We quantified the evolution and mitigation processes of hydrological drought through an integrated framework combining range theory and the Human Activity Impact Index (HADI), enabling separate assessments of human activity impacts during drought development and recovery phases. Furthermore, employing methods such as correlation analysis, we investigated how changes in environmental factors regulate the propagation mechanisms of meteorological-hydrological drought. New hydrological insights for the region: Human activities exerted a stronger influence on short-term than on long-term hydrological drought (mean HADI = 16.28 %) and generally aggravated drought by intensifying and accelerating the development phase. Although human activities slightly reduced recovery duration and increased recovery speed, these modest mitigating effects during recovery were insufficient to compensate for the stronger aggravating effects during drought development. Human activities also weakened the linkage between meteorological and hydrological drought and shortened drought propagation time. Among the examined factors, precipitation and vegetation cover emerged as key controls on drought propagation. These findings provide a quantitative basis for managing human activities in arid and semi-arid basins and for improving early warning and forecasting of hydrological drought.