基于层次分析法的再生水补给型城市河湖水生态修复技术评价指标体系及其应用

由于城市水资源严重紧缺，再生水作为补给城市河湖景观水体的重要水源，用量逐年加大，随之带来的水环境问题也引起关注，往往需要采用适宜的技术和工程改善水质。然而对于现有的生态修复技术和工程，缺少相应的评价方法和指标体系对其修复效果和工程技术进行综合有效的评估。通过大量的文献及实地调研，结合再生水补给型城市河湖的特点，构建了包含环境效益、技术管理与维护及社会经济功能3个系统、7个准则和19个指标的再生水补给型城市河湖水生态修复技术评价指标体系，采用群组决策的层次分析法（AHP）确定各指标的权重，重要性排序前5位的指标依次是：藻类多样性、水生植物覆盖度、DO、TLI、PI（COD）。以北京市陶然亭湖水生态修复工程为例进行综合评价，研究结果表明，现阶段陶然亭湖水生态修复工程综合评分为3.35分，评价结果属于良。陶然亭湖经过水体生态修复后，水生态系统结构较好恢复；所选工程技术适宜；人员及经济投入适中；对周边环境产生较大正面影响；工程可优后进行推广

Evaluation method of water ecological restoration technologies in urban river and lake supplied by reclaimed water established by analytical hierarchy:Establishing and application

Due to severe shortage of water resources in large city, the reclaimed water has been used as an important unconventional water source that was a good supplement for the urban river and lake landscape. The amount of reclaimed water increased significantly every year. The huge supply of reclaimed water led to the serious ecological and environmental problem. To solve it, many engineering technologies have been applied in urban river and lake landscape to improve the ecological and environmental quality. However, the present evaluation index and method were shortcoming for the evaluation of engineering technologies. In this study, through a large number of literature review and on-site investigation, an index system including 19 indexes, 7 criteria, 3 systems of environmental benefit was established to evaluate performance, technical maintenance/management and social economy function of engineering technologies. This evaluation and index system could be applied to remediate technological and environmental quality of the urban river and lake landscape that were supplied by the reclaimed water. A group decision-making model of AHP was employed to determine the weights of the indicators and the first five important index were algal biodiversity, aquatic plants coverage, dissolved oxygen (DO), comprehensive nutrition state index (TLI), and oxygen demand (PI or COD). At last, the Taoranting Lake in Beijing was studied as a case for comprehensively evaluating the effect of water ecological restoration. The evaluation result score showed a "good" state, indicating that the Taoranting Lake remediation engineering made a positive improvements on the water quality and ecosystem. The used engineering technology was suitable for the personnel and economic investment. This remediation engineering project could be widely applied after promoting.