地表水资源量的变化是随着补给源补给量的变化而变化的 ,人类活动可以改变地表水的补给源。解放以来 ,西北地区人口不断增加 ,经济不断发展 ,人类活动影响强烈 ,尤其是大面积的垦荒、大规模兴建水利设施和进行水土保持 ,以及植树种草等 ,对地表径流情势已经产生了较大影响。从问题严重性看 ,目前人类活动对地表水资源量影响最大的是地区分布和时程的剧烈变化 The variation of surface water resources varies with the recharge of recharge sources, and human activities can change the recharge source of surface water. Since the liberation, Northwest China’s population has been increasing, the economy continues to develop, human activities have a strong influence, especially large-scale reclamation, large-scale water conservancy facilities and water and soil conservation, as well as planting trees and so on. influences. Seen from the seriousness of the problem, the most significant impact of human activities on the amount of surface water resources at present is the drastic change in the regional distribution and schedule