Normally water resources is affected by human activities and climatic change , but it is affected mainly by climatic change in runoff forming regions located in the high and middle mountainous area in the northwestern china . river runoff in the hexi inland arid region all originates from the qilian mt . area and the change of mountainous runoff resulted from global weather warming up and will bring an important effect to the development of society and economy in the hexi region . so the response on mountainous runoff and its changing trends are analyzed on the basis of the measured data of precipitation , air temperature , and discharges observed from some weather and hydrologic stations in the studied area . the results show that seasonal variation of mountainous runoff in the hexi inland region is mainly affected by the river ' s geographical location and supply source , and the yearly change by precipitation and that in the west of the region by air temperature besides precipitation . there are some obviously regional differences in the influences of climatic change on surface runoff in the hexi inland arid region , that is , rivers runoff in the west of the hexi area have been increasing and rivers in the east part have been decreasing , and the rivers runoff in the central part presented slowly increase trend , such as the heihe river , but it is not quite obvious 一般情况下,水资源的变化主要受气候变化和人类活动的影响,但在位于我国西北内陆干旱地区的中高山地带,径流的形成主要受前者的影响.甘肃省的河西内陆干旱区是该省重要的工农业生产和经济开发区,这里各项社会和经济活动与出山径流的变化都有着十分密切的关系.因此,笔者根据有关水文气象台站的降水、气温和径流观测资料,分析了以黑河、昌马河、西营河等主要河流为代表的河西内陆区出山径流的变化特征与规律.结果表明,河西内陆区出山口径流的季节变化主要受地理位置和河流补给来源的影响,而年际变幅则受山区降水量年际变化及变幅的影响十分明显.目前,梨园河以西河流水量处于上升阶段,梨园河以东的河流则处于下降的阶段;以黑河干流莺落峡水文站年径流为代表的走廊中部地区的出山口径流正处于1990年开始的枯水段的上升段.但总体而言,河西内陆干旱区出山口径流的变化相对比较稳定.预计今后若干年内,河西内陆干旱区东段河流出山口径流的变化以偏枯为主,中段、西段河流出山口径流的变化以平水或平水偏丰为主
