新疆湖泊的近期变化

三十年来,新疆湖泊发生了较大的变化,按湖泊水面变化可分为干涸、基本干涸、缩小、变化不明显和扩大等五种类型,本文简要分析了湖泊变化的原因,湖泊变化和自然环境之间的关系。

RECENT CHANGES IN THE LAKES OF XINJIANG

The lakes of Xinjiang have had greatly changes since liberation. All the lakes there can be divided into 5 types according to their change in area: 1. dried up, 2. almost dried up, 3. shrinking, 4. changed mot much and, 5. expanding.The lakes in desert area tend to dry up, (for examples, the Nop Nor, the Manasi lake etc.) the lakes in the plain tend to shrink, (the Bositeng lake, the Wulungu lake etc.) and the lakes in mountain area remain their niginal out-look, (the sailimu lake, the Kanasi lake etc.)Recent changes in the lakes mainly include salinization of water quality and shrinkage in area and deepth. In the year 1958 the mineralization of the Bositeng lake was less than 0.4g/l, while in 1975 it rose to 1.5g/l, and in 1980 to 1.8g/l.The average annual increase was 0.06g/l which is quite amazing, in the year 1959 the Wulungu lake was 482.8 M. above-sea-level, while in 1969 it went down to 480.0 M. and in 1980 to 478.8M. 4 M. It has a total drop of about the last two decades.These changes make a profound impact on the ecosystem of the lakes. The area of desertifaication increased rapidly from 12% to 52% during the year from 1958 to 1978 around the Nop Nor region where a big lake had disappeared Biological resourses were degenarated in most of the lakes. Fishery output of the Wulungu lake decreased from 4000 tons to less an one thousand ton per years.Reed resourses of the Bositeng lake decreased from 0.4 million tons to 0.25 million tons per year during the same period.The cause of the changes is basically due to the influence of human activities. Large-scale reclamation reeds a huge amount of irrigation water from the rivers and it has to drain off salt water into the lakes. On the other hand, recent cyclical decrease of runoff is another important reason of the changes.The methods to prevent the lakes from becoming arid land and the way to utilize the lakes for multiple purposes are also discussed.