Analyzing the impact of land use changes on hydrological drought in the Yiluo river basin based on SWAT

This study investigates the hydrological cycle and drought dynamics in the Yiluo River Basin, focusing on the quantitative assessment of how land use and land cover change (LUCC) has influenced hydrological droughts from 1980 to 2000. Using the Soil and Water Assessment Tool (SWAT), we analyzed the mechanisms by which LUCC affects multiple dimensions of drought, including its spatial extent, frequency, duration, and intensity, combined with run theory to identify drought events. The results indicate that land use change significantly intensified drought conditions across the basin. The area affected by severe and extreme droughts increased by 1.41%, while 73.87% of the basin exhibited a significant rise in drought frequency, particularly for moderate and higher drought categories. The average drought duration extended by approximately 0.87 months, with the middle and upper reaches being most affected. Moreover, 85.30%, 78.69%, 74.15%, and 71.34% of the watershed area experienced strengthened intensity for mild, moderate, severe, and extreme droughts, respectively. These findings demonstrate that LUCC aggravated drought primarily by increasing surface runoff and reducing baseflow and evapotranspiration, thereby weakening soil infiltration and groundwater recharge. This study elucidates the mechanisms linking land use dynamics to drought evolution through alterations in hydrological processes and local climatic feedbacks, providing a scientific basis for ecological protection, adaptive land management, and urban resilience enhancement under ongoing climate and land use pressures. • This study uses SWAT to build a novel multiscale "LUCC - drought response" assessment framework. • It finds that LUCC has significantly worsened drought conditions in the YiLuo River Basin. • LUCC drives drought by changing hydrology, vegetation ET, and climate feedback. • This study provides a framework for global land-use optimization and ecosystem management. • A multi-dimensional drought index system quantified LUCC's spatial impacts across drought levels.