The variations characteristics and respond to climate change of runoff of Main Rivers in Gansu

In this paper, the long-term variability and response to climate change of runoff of main rivers in Gansu province are analyzed by meteorological and hydrological data. The results show that the fundamental features of runoff in seasonal change are non-uniform distribution of annual runoff, concentrated runoff in flood period, deficit runoff lower in spring and winter and drought at the end of spring and early summer. In the past 40 years, the annual runoff of Shulehe river in west section of Hexi area has obvious trend to increase, the annual runoff of Heihe river in middle section has slight trend to increase and the increase becomes salient in spring; The runoff of Shiyanghe river, Huanghe River and Jialingjiang river all tend to decline, and the southeastern Jialingjiang river, Jinghe river and Weihe river has the most distinct declining tendency. The variable features of runoff has close correlation to climate change.