Response of runoff variation to the changing environments of karst regions in southwest China

Abstract

How streamflow responds to changing environmental conditions is critical for a better understanding hydrological processes in ecologically vulnerable areas such as the karst region of southwest China. The Budyko framework and slope change ratio of cumulative quantity method (SCRCQ) were used to identify and quantify the contributions of changing environmental factors to streamflow variations for 8 large catchments in the region. Sensitivity analysis showed that interannual variation in runoff over 1960–2016 was more sensitive to land characteristics than to climatic factors. The contribution of climatic factors ranged from -95 to 261%, whereas that of land characteristics from -161 to 195%. Parameter values increased linearly as NDVI increased over time, which were also related to the fraction of carbonate rocks in these catchments among the 8 catchments examined. Vegetation cover, topography, and underlying geology as catchment characteristics in addition to climate affect the streamflow variations the karst region in southwest China.