塔里木河下游水量转化特征及其生态输水策略

2000—2015年的生态输水对塔里木河下游生态恢复发挥了重要的作用。通过连续16 a的动态监测和野外数据采集,对生态输水的特点、方式、水量转化特征、生境变化和影响范围等进行了系统的分析,同时对生态输水策略与生态保护模式进行了初步探讨。结果表明:(1)主河道线状输水方式,难以扩大环境响应范围,开展汊河输水和面状输水是十分必要的;(2)水量转化和耗散比例为:补给地下水44.2%,土壤与植被消耗48.8%,入湖水量与河道内水面蒸发7%;(3)地下水响应的最大距离为1 000 m,在距河500 m范围地下水位上升、水质好转显著;(4)鉴于生态退化的趋势得到遏止,但其脆弱性依然没有根本转变,恢复并合理调控其文阔尔河和老塔里木河区间的地下水位,扩大受水区范围,建立更加稳固的生态恢复平台,是今后生态输水与生态环境保护的主攻策略。

Water Conversion and Strategy of Ecological Water Conveyance in the Lower Reaches of the Tarim River

During the period from 2000 to 2015,ecological water conveyance played a crucial role for ecological regeneration in the lower reaches of the Tarim River.In this paper,the ecological water conveyance and its ways,water conversion,environment change and affecting extent were analyzed based on the data of field observation and dynamic monitoring of hydrological regime,and the ecological water conveyance strategy and ecological protection mode were discussed.The conclusions are as follows:① It was difficult to expand the scope of environmental response by water conveyance in the main river channel,and it is necessary to take the ways of branching or overflow;② Proportions of groundwater recharge,soil and vegetation consumption and water flowing into the lake and river surface evaporation were 44.2％,48.8％ and 7％ respectively;③ The maximum responsive range of groundwater was 1 000 m away from the river channel,and groundwater level and water quality was effectively improved within 500 m away from the fiver channel;④ Although the trend of ecological degeneration was stopped,the ecological vulnerability in the lower reaches of the Tarim River was not fundamentally changed.In the future,it should be paid great attention to recovering and regulating groundwater level,expanding the flooding extent,and establishing a more stable platform of ecological regeneration.