塔里木河下游生态输水的合理时间初探

基于塔里木河下游8次生态输水资料和植被调查,从输水时间与天然植被落种时间的生态默契角度,分析了8次输水时间、水量以及博斯腾湖与塔里木河来水的规律,并根据塔里木河下游32种植物的落种时间,分别从不同乔、灌、多年生草本和一年生草本植物的落种与河道过水时间的相关性,对目前输水时间的合理性进行了评判,从塔里木河下游天然植被生态恢复的角度,提出了塔里木河下游最适宜的输水时间。结果显示：①由于调水沿途损耗较大,目前输水正以博斯腾湖调水向依靠塔里木河来水转变,因此,塔里木河有没有水向下游输送是生态输水的先决条件;②前8次输水过程中,过水时间主要集中在4-6月和8-10月两个时间段,这是由于博斯腾湖水量49.73%在4-6月;而塔里木河水量82.33%集中在8-10月;③从8次输水看,由于没有考虑到天然植被的落种更新问题,因此,河道过水时间与天然植被的相关性偏低,塔里木河来水的输水时间较博斯腾湖更为合理;④从下游乔、灌、草落种时间看,最适宜的输水时间是7-9月;从塔里木河给水时间的可行性看,每年最佳的给水时间是8月中旬到9月底。

Primary Study on the Rational Time of Ecological Water Conveyance to Lower Reaches of the Tarim River

In this paper,the time and volume of 8 times of ecological water conveyance to lower reaches of the Tarim River was analyzed based on the data of ecological water conveyance and the field investigation on natural vegetation.The change of water volume from the Bosten Lake and the Tarim River to the lower reaches was summarized.The correlation between the seed falling time of 32 plants species and the watering time of the river course in the lower reaches of the Tarim River was analyzed,and the beginning time of ecological water conveyance was discussed.Furthermore,the feasible and rational beginning time of ecological water conveyance was put forward for conserving and regenerating natural vegetation in the study area.The results are as follows:(1) Because of the serious water consumption along the river channel,conveyed water for the ecology is mainly relied on stream flow of the Tarim River instead of the Bosten Lake.So it is a precondition that whether water resources in the mainstream area of the Tarim River are enough or not;(2) The 8 times of ecological water conveyance were mainly implemented during the periods from April to June and from August to October,because 49.73% water flows into the Bosten Lake and 82.33% water flows into the Tarim River during these periods;(3) The correlation between the watering time of the river course and the regeneration of natural vegetation was low,because the seed falling time of natural vegetation was not considered previously.Therefore,it is more rational to convey water from the Tarim River than from the Bosten Lake;(4) Judged from the seed falling time,the period from July to September is the most rational,however,that from mid-August to the end of September is the most reasonable if judged from stream flow of the Tarim River.