坝上察汗淖尔湖水面萎缩原因及其恢复对策

Studies on Water Surface Shrinkage in Chahannaoer Lake and Environmental Restoration

本文为了探究坝上察汗淖尔湖水面萎缩原因,从自然和人为两个方面进行分析,可为察汗淖尔湖的生态恢复政策制定提供参考。采用Mann-Kendall(M-K)分析方法探讨了近60年察汗淖尔湖周边地区气温和降水的变化趋势以及突变情况。从土地利用图分析了人为灌溉用水量的变化。定量分析了流域水量平衡情况。结果显示:气温在1983年存在突变点,在1988年之后呈现明显上升趋势,气温的升高导致湖水每年蒸发量增加。流域内降水量不存在明显突变点与变化趋势。土地利用类型变化分析中,一般耕地与中央灌溉圈的变化最为明显。当中央灌溉圈建设完成后,原有水量平衡被打破,察汗淖尔湖的蓄水量逐年减少。为遏制湖面萎缩趋势,当务之急是减少灌溉面积。建议至少缩减40%的人为灌溉面积,并利用中水补给,采取流域综合管理等对策。

We analyzed the causes of water surface shrinkage in Chahannaoer Lake in Bashang Plateau from natural and man-made aspects,so as to provide reference for the formulation of ecological restoration policies in Chahannaoer Lake.Mann-Kendall( M-K) analysis method was used to discuss the change trend and sudden change of temperature and precipitation in the surrounding area of Chahannaoer Lake in the past 60 years.The change of man-made irrigation water consumption was analyzed from the land use map.The water balance of the basin was quantitatively analyzed.The results showed that There was a sudden change point in 1983,and it showed an obvious upward trend after1988.The increase in temperature led to an increase in the annual evaporation of the lake water.There is no obvious abrupt change point and change trend of precipitation in the basin.In the analysis of land use type change,the change of general cultivated land and central irrigation circle was the most obvious.When the construction of the central irrigation circle was completed,the original water balance was broken,and the water storage capacity of Chahannaoer Lake decreased year by year.In order to curb the shrinking trend of lake surface,the urgent task is to reduce the irrigation area.It is suggested that the man-made irrigation area should be reduced by at least 40%,reclaimed water should be used for replenishment,and integrated watershed management should be adopted.