Spatial and Temporal Dynamics of Water Conservation in Xiangjiang River Basin Based on ANUSPLIN and InVEST Model

Climate change and human activities have had a significant impact on water conservation within the basin, and an in-depth study of the spatial and temporal dynamics of water conservation within the basin is essential for understanding the pattern of change and developing corresponding management strategies. This study evaluated the simulation results of the Xiangjiang River basin at different spatial and temporal scales from 1991 to 2020 based on the ANUSPLIN interpolation precipitation data and the InVEST model and explored the spatial and temporal dynamics of water conservation within the basin. The results of the study show that: ① the ANUSPLIN precipitation input-driven InVEST model shows good simulation results at different time scales in the Xiangjiang River basin (annual water yield, NSE = 0.792; seasonal water yield, NSE = 0.734). ② Precipitation (slope = -3.053 mm/y), water yield (slope = -4.028 mm/y), and baseflow (slope = -4.167 mm/y) in Xiangjiang River basin from 1991 to 2020 show an overall decreasing trend; evapotranspiration (slope = 3.638 mm/y) and surface runoff (slope = 0.364 mm/y) show an overall increasing trend. ③ The annual water yield in the western part of the Xiangjiang River basin is low and shows a significant decreasing trend, and the local baseflow exhibits a decreasing trend to varying degrees, while the annual water yield in the southern part of the basin and the eastern edge of the basin is relatively high. ④ Spatial and temporal dynamics of water conservation and land use types within the basin over a 30-year period show that the shift from natural cover to land use for production and living would lead to a reduction in water conservation capacity. This study can provide a basis for the development of effective water resource management and climate adaptation strategies.