Analysis of hydrological drought characteristics and drivers in Jialing River basin

Here is the revised academic English translation, updated according to your latest specification:The Jialing River is the largest tributary of the Yangtze River by drainage area and serves as a vital “water artery” for the high-quality development of the Chengdu-Chongqing economic circle． Under the superimposed pressures of global climate change and human activities, regional ecological and environmental protection is facing new challenges． Based on multi-source data including surface runoff, precipitation, evapotranspiration, and groundwater level in the Jialing River Basin from 1990 to 2020, this study applied the Standardized Runoff Index (SRI), run theory, Geodetector, and structural equation modeling (SEM) to investigate the characteristics and driving factors of hydrological drought in the basin． The results indicate the following: 1) As the statistical time scale lengthens, hydrological drought exhibits an evolution pattern of lower frequency, longer duration, and higher severity, with spatial heterogeneity consistently present across short-, medium-, and long-term scales． 2) The SRI series at different time scales, calculated from hydrological stations in the basin, displays pronounced spatiotemporal variability in its evolution, within which the year 2007 is identified as a critical turning point in hydrological drought development． 3) Over the past 30 years, groundwater has consistently been the primary positive regulating factor of hydrological drought, with its total effect declining from 0.37 before the turning point to 0.23 after． Evapotranspiration acts as the primary negative regulating factor, and its total effect weakened from −0.30 before the turning point to −0.16 after． Notably, after the turning point, the total effects of both cropland and built-up land exceeded that of human water use, indicating that the intensification of hydrological drought driven by land use change has gradually replaced direct human water use as a significant driving mechanism． These findings can provide theoretical support for water resources security and drought prevention and control in the upper and middle reaches of the Yangtze River．