新条件下长江镇扬世业洲段演变对河流功能的影响

Impact of River Evolution on River Functions at Shiye Sandbar of Zhenjiang-Yangzhou Reach of Yangtze River under New Conditions

随着社会经济的快速发展,包括三峡工程在内的强人类活动对长江下游河道自然演变造成了巨大影响,进而对下游河道的河流自然和社会功能产生影响。选取14个指标分别表征河道演变对防洪、通航、岸滩保护利用、水资源、水生态环境共5个功能的影响,构建长江下游河道演变对河流功能影响评价体系,采用专家打分法和层次分析法相结合的方式确定了指标权重,制定了各指标的量化与赋分标准,以长江下游世业洲汊道段进行实证研究。结果表明三峡工程蓄水后(2019年)大部分指标相比于蓄水前(2002年)都有不同程度变好,但也存在河岸稳定性、涉水工程群影响和水生物多样性降低等问题。构建的评价指标体系和评价结论对长江河道保护与治理具有一定的推广意义。

With the rapid development of social economy, strong human activities including the Three Gorges Project have had a great impact on the natural evolution of the lower Yangtze River, and further affected the river’s natural and social functions. In this research we establish an evaluation system containing fourteen indicators to represent the impact of river channel evolution on five major functions of river channel, namely, flood control, navigation, bank and shoal protection and utilization, water resources, and water ecological environment. In subsequence, we determine the weights of the indicators by integrating expert scoring method and AHP method, and formulated the quantification and scoring standards of each indicator. Application to the Shiye sandbar branch in the lower Yangtze River manifests that, after the impounding of the Three Gorges Project(2019), most indicators have improved to varying degrees compared with those before the impounding(2002). Yet, problems still exist. Such problems include the stability of river bank, the impact of water-involved project groups, and the reduction of aquatic biodiversity. The evaluation index system and conclusions of this paper is of popularization significance for the protection and governance of the Yangtze River.