黑河流域水资源转化特征及其变化规律

黑河流域水资源主要以冰雪水资源、 地表水资源与地下水资源的形式存在.上游祁连山区分布有现代冰川428条, 发育大小河流共计29条, 多年平均出山径流量37.83×10⁸m³·a^-1; 中下游走廊平原由松散沉积的第四系盆地组成, 接受出山河水及引灌河水的入渗补给, 是地表水资源的重复表现形式, 地下水补给量为25.637×10⁸m³·a^-1.受构造-地貌条件的制约, 自南部山区至北部盆地, 地下水与河水之间经过5个不同地带有规律的、 大数量的、 重复的转化过程, 形成完整统一的"山区地下水-出山地表水-中游盆地地下水-中游盆地地表水(泉水)-下游盆地地下水"水资源循环转化系统.

Characteristics and Conversion of Water Resources in the Heihe River Basin

The Heihe River basin, located in the interior of Northwest China, is one of the well-known arid and water-shortage areas in China. Water resources mainly take the form of glacier-snow resources, surface water resources and groundwater resources. The Qilian Mountains at high altitude is the headwaters, i.e., the runoff production zone. The middle and lower reaches of the river, mainly in plain, is a main irrigation zone for agriculture, i.e., a water consumption zone. The upper reaches of the river have as many as 428 glaciers, covering an area of 420.55 km², with glacier resources of about 136.7×10⁸m³. There are 29 sub-rivers, large and small, in the upper reaches of the river, with a mean annual runoff of 37.83×10⁸m³·a^-1 from the mountain areas. The runoff from mountain areas is relatively stable. However, an increasing trend has been seen in recent 10 years. The middle and lower reaches of the river are located mainly in plain. The plain zone of the river includes four large tectonic basins, where groundwater is mainly recharged by infiltration of river water and irrigation channel water. The mean annual groundwater recharge is about 25.637×10⁸m³·a^-1. In recent 45 years, with the sustainable development of industrial and agricultural economy, the change in utilization and allocation of water resources, which is due to the increasing sophistication of developing water conservancy in the zone, in addition to the influence of the climate shifting to dry, the total groundwater recharge has decreased by 13.043×10⁸m³, with a decreasing amplitude of 41.3%, and as a result, spring water resources have decreased 22.3%. There are regular, massive, repetitious conversion processes between groundwater and river water along the river. The water resources conversion system exhibits: groundwater in the mountain zone→surface water in the mountain foot→groundwater in the southern basin→surface (spring) water in the middle basin→groundwater in the northern basin. A correct understanding of the water resources characteristics and conversion is undoubtedly a base of achieving the sustainable development of industrial and agricultural economy in the Heihe River basin and adjacency.