Abstract: The middle route of the South-to-North Water Diversion Project is an important part of the National South-to-North Water Diversion Project, and is a major strategic basic project to ease the serious shortage of water resources in Huanghuaihai Plain and optimize the allocation of water resources. As the water source region of the middle route of the South-to-North Water Diversion Project, climate change and human activities in the upper reaches of the Hanjiang River Basin have changed the natural hydrological situation. Research on the temporal and spatial variation of hydrological elements such as precipitation and runoff is an important basis for the scientific planning and implementation of the middle route of the South-to-North Water Diversion Project. Based on the mathematical statistics and hydrological model methods, this study carried out the variation and attribution analysis of the hydrological elements in the upper reaches of the Hanjiang River Basin. It is demonstrated that both the precipitation and runoff series have been detected with decreasing trends, and abrupt change points are also detected for both series in the year of 1990. Only the decreasing trend of the runoff is significant. The annual average runoff in the upper reaches of the Hanjiang River Basin during 1991-2016 decreased by 8.12 billion m3 compared with 1962-1990. About 43.2% of the deficit are affected by climate change, and about 56.8% are affected by human activities. It is concluded that the research results of this study can provide a scientific basis for the operation and management of the middle route of the South-to-North Water Diversion Project.

Key words: the South-to-North Water Diversion Project, climate change, trend examination, change point examination, hydrological model