通过对甘肃省主要河流径流时空分布规律的分析研究,得出干旱缺水的主要原因是各河年径流丰水时段很短,一般只有2～3年;枯水时段很长,可达7～26年;祁连山区许多河流多年均值基本稳定。并预测从1998年开始至2009年,全省诸河水量从枯水年代转向平水到偏丰的年代;建议全省必须树立长期抗旱的思想,水资源利用必须进行系统分析优化配置。

We got the main reason of aridity from studying on the time-space distribution regulation of runoff of main rivers in Gansu province. That is, for all of the main rivers, annual runoff quantity,plentiful (rich)water period was very short ,generally ,only last 2～3 years; But low water period was very long may last 7～26 years. The average runoff remained steady basically for many years to many rivers in Qilian mountain regions; And we forecasted that the water quantity of all main rivers in whole province will change from low water years to more than normal water years from 1998～2009. The author suggested that everyone should establish a thought of anti-drought for long times.The utilization of water resources must be reasonable and optimal arrangements based on systematic analysis.