在对近年国内外城市水系连通典型案例总结的基础上，构建包含水系格局、结构连通性和水力连通性3个准则层的平原城市河网水系[JP2]连通性评价体系，改进水力连通性准则层中水力连通能力指标的计算方法，使其适用于整个河网计算。为避免主、客观单一权重法的不足，采用AHP-熵综合权重法对评价指标赋权。针对通过指标值评价水系连通状况不能兼顾多因素影响的局限性，采用综合评价法对廊坊城区不同水系连通方案的水系连通状况进行评价。结果表明，该体系能够较全面地对平原城市河网进行水系连通性评价，为我国平原城市河网水系连通性评价提供参考。

Under water conservancy projects control such as gates and pumps,the complex river network in plain cities has a complicated water flow and a blocked water system,which affects its self-purification capacity.Instead,there are diverse factors that affect water system connectivity,makes more uncertain due to the regulation of dam gates.Therefore,the system pattern,structural connectivity,and hydraulic connectivity should be integrally considered to evaluate the connectivity of river networks in plain cities. Taking the optimal solution of water system connectivity as the target layer and water system pattern,structural connectivity,and hydraulic connectivity as the criterion layer,considering both static and dynamic factors,four indicators of water surface rate,river network density,river frequency,and river channel storage were selected to evaluate the morphological characteristics of urban water system more comprehensively.Water system ring degree,node connection rate,and water system connectivity were selected to evaluate structural connectivity.Based on structural connectivity,the influence of water flow capacity on the connectivity of the water system was fully considered,and three indicators of flow velocity,water flow potential,and water level are used for hydraulic connectivity evaluation.The above 10 evaluation indicators are used as the index layer to build the water system connectivity evaluation system.To comprehensively evaluate the water system connectivity of different schemes,a comprehensive evaluation method is used to assign weights to the 10 indicators,and then to comprehensively evaluate different water system connectivity schemes. Taking Langfang urban water system as an example,the water system connectivity evaluation system of the plain city river network was constructed to quantitatively evaluate the water system connectivity status of eight water system connectivity schemes.The results showed that there were differences in the three criterion levels of water system pattern,structural connectivity,and hydraulic connectivity for different working conditions.Combining the comprehensive evaluation scores and the grade cut-off values,the optimal water system connectivity solution can be obtained to improve the water system connectivity of the whole river network for Langfang city and could suggest that the river network should open the Shengli branch canal,Shengfeng branch canal,and Xiaoliuzhuang branch canal in the water transmission process,and dredge and desilt of the three branch canals with serious pollution according to the local actual situation. The system can evaluate the water system connectivity of the plain city river network in a more comprehensive way,and reflect the water system connectivity status of different water system connectivity schemes.The hydraulic connectivity index can reflect the mobility of water bodies in water systems.The calculation method of the hydraulic connectivity index in the hydraulic connectivity criterion layer was improved,so that it can be applied to the whole river network,making up for the limitation that the index was only applicable to the calculation of a single river in the past.To address the limitations,the evaluation of water system connectivity by index values can not take into account the influence of multiple factors,based on the water system connectivity evaluation system.The AHP-entropy integrated evaluation method was used to evaluate different water system connectivity schemes in terms of water system pattern,structural connectivity,and hydraulic connectivity to obtain the final evaluation scores of different water system connectivity schemes,to determine the optimal solution for water system connectivity and to make reasonable planning suggestions for the whole river network.The overall connectivity of the river network is optimal after connecting the three heavily polluted rivers with other rivers.