Abstract: Hanjiang River basin is an important water-supporting area of the middle route project of South-North Water Transfer. The coordinative regulation of water resources in the Hanjiang River basin is conducive to promoting water resources protection and development of the Hanjiang River economic belt. We simulate and analyze the changes in precipitation, temperature, blue and green water resources and their responses to climate variability and land use changes in the Hanjiang River basin from 1985 to 2019 using the SWAT (Soil and Water Assessment Tool) model and mathematical and statistical methods such as the Mann-Kendall (M-K) test. Results elucidate that in the past 35 years, the multi-year average green water resource in the Hanjiang River basin is about 1.74 times higher than the multi-year average blue water resource. Spatially, both blue and green water resources show a trend of gradual increase from the west and north to the southeast. Changes in blue and green water resources in the basin are influenced by both climate and land use, with climate change being the main factor and land use changes being less influential.

Key words: blue water resource, green water resource, SWAT(Soil and Water Assessment Tool) model, climate change, land use change, Hanjiang River