Interactive driven force analysis of blue and green water for Yalong River Basin of southwest China based on a hybrid modeling approach

Yalong River Basin, southwest China Hydrological cycle has been affected by environmental changes, leading to serious freshwater crisis. In this research, hydrological modeling along with detrend techniques were advanced to address the blue and green water components responses to climate change and anthropogenic disturbances. Blue and green water exhibited upward trends from 1967 to 2017. In two studying periods (P1: 1981–1996; P2: 1997–2017), land use/land cover change exerted a slight effect of −2–2 mm variation in blue and green water in most subbasins. Climate change exhibited the dominant role in hydrological variations, in which the contribution of precipitation was the highest for blue and green water storage and temperature for green water flow. Rising precipitation led to an increase in blue water of overall 5–25 mm in P1 and 25–80 mm in P2. Rising temperatures caused increased green water flow, from 0–15 mm in P1 to 2–30 mm in P2. From P1 to P2, climate change’s effect on green water storage showed a negative trend in certain subbasins due to intensified warming. Spatially, regulated by catchment distributions and land cover types, the responses of blue water and green water storage to climate change presented higher heterogeneity than green water flow. This study illustrates how interactive factors modulate blue water availability and ecological water requirements in heterogeneous environments. • Climate change exerted the dominant role in the increasing trends of blue and green water in YLRB. • Precipitation dominated green water storage and blue water changes, while temperature governed green water flow. • Green water flow responded uniformly to climate while green water storage and blue water varied with land use. • The hybrid model disentangled human-climate interactions to identify key drivers of blue-green water dynamics.