Abstract:
Water transfer is an effective measure to enhance hydrodynamic and water quality in highly urbanized areas. The effect of water transfer in highly urbanized areas is affected by strong artificial interventions, and it is difficult to evaluate the improvement of multiple indicators of many sections after water transfer. At present, there is no analysis framework directly evaluates the improvement of water environment under strong artificial interventions, making it difficult to determine the optimal scheduling of hydraulic projects. This study constructed a multi-criteria analysis framework for evaluating the improvement of water environment including index layers of water quality improvement, hydrodynamic improvement and economic cost, and designed corresponding element layers for each index layer. The weights of each element were determined based on fuzzy analytical hierarchy process, and the fuzzy comprehensive evaluation method was used for comprehensive evaluation. The framework was applied in Xishan District in highly urbanized Taihu Lake Basin, and the results showed that the proposed framework could effectively determine the optimal scheduling of hydraulic projects. Water quality compliance rate for the optimal water transfer scheme achieved in Xishan District was 82%, average rate of water quality improvement was 31%, and proportion of cross-sections meeting the Class III water quality standard was 61%. Average flow velocity was 0.10 m/s, proportion of the optimal velocity was 39%, and proportion of stagnant sections was 32%. Furthermore, the impact of regional control projects on the effect of water transfer was much greater than local projects, consequently, the best scheduling mode for regional control projects should be first determined, and then the scheduling combination for local projects. This study can provide a new framework for the assessment of water transfers to improve the water environments and a scientific basis for the dispatching of hydraulic projects in Taihu Lake Basin.
摘要:
调水是提高高度城市化地区水动力和水质的有效措施。高度城市化地区的调水效果受到强有力的人为干预的影响,调水后多个断面的多项指标改善情况难以评价。目前,没有直接评价强人为干预下的水环境改善的分析框架,很难确定水利工程的最优调度。本研究构建了一个评价水环境改善的多准则分析框架,包括水质改善指标层,水动力改进和经济成本,并为每个索引层设计了相应的元素层。基于模糊层次分析法确定各要素的权重,采用模糊综合评价法进行综合评价。该框架在太湖流域高度城市化的西山区得到了应用,结果表明,该框架能够有效地确定水利工程项目的最优调度。西山区最优调水方案水质达标率为82%,水质平均改善率为31%,满足III类水质标准的横截面比例为61%。平均流速为0.10m/s,最佳速度的比例为39%,停滞段的比例为32%。此外,区域控制项目对调水效果的影响远大于地方项目,因此,首先应确定区域控制性项目的最佳调度模式,然后是本地项目的调度组合。该研究可为太湖流域水环境改善调水评估提供新的框架,为太湖流域水利工程调度提供科学依据。