Abstract

ABSTRACT Runoff is a pivotal ecohydrological cycle feature. Investigating watershed runoff change and its influencing factors from multi-temporal and spatial angles is crucial for water ecology control. The study analyzes hydrological and meteorological changes using the indicators of hydrological alteration and the range of variation approach (IHA–RVA) and RClimDex to explore their dynamic relationship. Finally, using the soil and water assessment tool to quantify climate and human contributions to runoff temporally and spatially, with validation using Budyko-based elasticity coefficients. Results showed that (1) most of the meteorological indices show an upward trend, a change attributable mainly to strong human activity and global warming. The overall hydrological indicators show a moderate degree of change (50.70%). (2) PRCPTOT (the annual total precipitation) and 30-day minimum demonstrate a negative correlation coefficient of 0.91 in the meteorological–hydrological response. (3) On annual/seasonal scales, human activities such as hydraulic projects and land use/cover changes (LUCC) dominate runoff changes. On a monthly scale, climate change prevails in March and November due to temperature/rainfall fluctuations, while human activities dominate other months. Spatially, climate change and LUCC mainly impact runoff in the southeast. The study offers references to improve water management in the Jialing River Basin, effectively addressing the negative impacts of human activities on runoff.