中国干旱区水量转化特征及其对环境的影响分析--以新疆阿拉尔灌区为例

新疆的水平循环是，径流形成于山区，流到平原区后不断蒸发和渗漏，最终消耗在沙漠中，或者流入尾闾湖。由于人类活动的影响，水的分布和转化都发生了改变，绿洲中的水量增加，但绿洲以外与河流下游的水量减少，同时有些湖泊缩小甚至干涸，沙漠化发展，自然植被衰退，自然环境退化。

THE CHARACTERISTICS OF WATER TRANSFORMATION AND ITS EFFECTS TO ENVIRONMENT IN XINJIANG --A case study at Alar irrigation area

The regularities of water transform in stream forming area and disappearing area are quite different. In stream forming area, water transform is mainly that groundwater flows out to form surface water. And in stream loss area, water transform is mainly that surface water seeps into ground. At the perimountain plain, when the transform of surface water-groundwater- surface water finishes, it may begin the second transform if there is a structural basin in the lower reaches of rivers. However, water becomes less and less after the process of transform. Effect of water to environment can be divided into two types, natural effect and human effect. The changes of natural conditions need a long time of geological period. The influences of human activities take place in a short time and regionally, especially in arid land where water is the key factor of environment. Hydrological changes in Xinjiang are mainly that: part of river courses has been replaced by artificial canal system; some lakes are replaced by reservoirs; and water table has changed. Located at the upper reaches of Tarim River, Afar irrigation area is reclaimed after 1958. With the expansion of irrigation area after land reclaiming, much of water seeped into ground from canals and farmland to feed groundwater. Seasonal change of water table is based on irrigation periods. Mineralization of groundwater has reduced but most of the drained water flows into rivers or lakes, river water quality has changed too. The redistribution of water is mainly that: water quantity has been improved within oases, but runoff in the lower reaches has reduced. Alar irrigation area is the largest new oasis with stable agricultural eec-environment in Tarim Basin since the redistribution of water resources. Hydrological and climatic conditions are improved within the oasis.