苏干湖盆地水资源与生态环境及其向区外调水的影响

Water Resources and Ecological Environment in Sugan Lake Basin,and the Effect of Water Diversion out

苏干湖水系属于柴达木内流水系西北端的一个独立水系,在现状条件下,苏干湖盆地水循环关系为大小哈尔腾河-苏干湖的"补给-蒸发"相平衡.大小苏干湖为盆地水资源的尾闾汇集区,生态景观大部分为戈壁荒漠,生态植被集中分布在湖外围地下水埋深小于5m的浅埋带.在评价分析现状水均衡的基础上,分析了盆地水循环过程,结合氢氧同位素测试和遥感信息提取,得出大、小苏干湖水体的补给来源不同,河流来水量的变化主要反映在大苏干湖水域,对小苏干湖水体影响较小.初步建立了苏干湖盆地生态植被变化模式,结合引哈济党工程,分析了不同调水情景下,大苏干湖水体面积的变化、地下水浅埋带的变化及生态变化.结果表明:在大哈尔腾河调水1.0×108 m3时,不会对苏干湖水系生态状况造成明显的影响,因而可对敦煌生态保护起到积极作用.

As an independent water system,the Sugan Lake water system is located in the north-west part of the Qaidam basin.River water from Harten River supply Sugan Lakes.There is water balance between river water supply and evapotranspiration from the basin.Large Sugan Lake and Small Sugan Lake are the tail of the catchment area of the basin.The major ecological landscape in the basin is Gobi desert,with a small part of ecological vegetation scattered around Large Sugan Lake and small Sugan Lake,where groundwater is less than 5 m in depth.Based on water balance evaluation,water cycle ways are analyzed for the basin.Combining with hydrogen and oxygen isotope determination and remote sensing information extraction,the following conclusion can be drawn that water recharge sources are different in Large Sugan Lake and small Sugan Lake.Change in input water from Harten River will sensitively reflect in Large Sugan Lake,and almost not any signal can be seen in small Sugan Lake.An ecological vegetation change mode is established on the basis of investigation.According to the mode,the changes in water area of Large Sugan Lake,in groundwater depth and in ecological vegetation are predicted under different diversion scenarios.It is concluded that 1.0×108m3 water diversion from Harten River will not significantly damage the ecosystem around the Sugan Lakes,but will improve the ecosystem in Dunhuang basin greatly.