Assessing impacts of vegetation changes on water availability in the upper Yellow River Basin, China

Changes in vegetation are expected to influence terrestrial water and energy fluxes; however, the impacts of vegetation changes on water availability remain controversial. In this study, we applied the Community Land Model, version 4.5 (CLM4.5) coupled with the Variable Infiltration Capacity (VIC) hydrological parameterizations to the upper Yellow River Basin (UYRB), which is the most important water conservation area in the Yellow River Basin, to investigate the impacts of vegetation changes on water availability in the area. The results showed a pronounced greening trend in the UYRB from 1982 to 2018, resulting in increased evapotranspiration, decreased runoff, drier soil conditions, and decreased water yield. The water reduction effect of vegetation greening is more pronounced in water-limited areas than in energy-limited areas. This study highlights the diverse hydrological responses to vegetation changes under different climatic conditions and land cover types. It is crucial for ecological restoration policies in China to recognize these distinctions and their potential negative impacts on water availability, especially in water-limited regions.