中国干旱区径流的形成及转化

中国干旱区面积约占全国总面积的1/3,是开发潜力较大的地区。但水资源紧缺。研究干旱区径流的形成与转化后可以得出:山区是径流的形成区。平原是径流散失区,水文的地带性规律非常显著。山区是地下水补给了地表水,成为河川径流中的基流。平原地表水通过各种渗漏途径补给了地下水,而平原在扇缘出露的泉水又成为平原河流的主要组成部分。这种地表水与地下水相互转化的特点为水资源的合理利用提供了科学的依据。

FORMATION AND TRANSFORMATION OF RUNOFF IN ARID REGIONS OF CHINA

The so-called arid regions of China in this paper do not include the semiarid regions and only refer to such lands as Xinjiang, the Hexi corridor of Gansu, the Qaidam basin of Qin-ghai, northern Ningxia, western Inner Mongolia, etc.The runoff in China's arid regions shows horizontal zonality and vertical zonality, the latter being more obvious. The lofty mountain masses, such as Altai, Tianshan, Qilian, Kun-lun, Altun, Helan, ect., are capable of intercepting moist air currents to produce mere precipitation than that occurring on the surrounding plains. Therefore, from the viewpoint of runoff situation, the arid regions can clearly be divided into the belts of the runoff formation and those of the runoff disappearance. The runoff formation belts and the runoff disappearance belts in arid regions have fundamental difference in hydrological regime.The hydrological regime of the river and its evolution depend mainly upon the supply sources of the runoff. The diversity of the runoff supply sources is one of the hydrological cha-racteristilies in the arid regions. The melt water from the alpine ice and snow has great impact on the hydrological regime of the river.The groud water of the piedmont plain comes mainly from surface water, while the river water below the plain comes partly from ground water. Between the river water and the ground water exists a relation of mutual supply, i.e., mutual transformation.