城市水生态网络韧性评价与优化策略——以长沙市为例

Resilience Evaluation and Optimization of Urban Water Ecological Network:Take Changsha as an Example

韧性视角下研究城市水生态网络的优化,提高水生态空间的韧性,是提升城市整体韧性水平的重要途径。文章首先将韧性城市目标与水生态网络结合,提出从水生态网络结构韧性、功能韧性以及调控管理韧性三个层次构建韧性的城市水生态空间;其次以长沙市作为典型案例,应用MSPA模型和MCR模型,识别并构建基于“源地—廊道—节点”的水生态网络,同时融合韧性城市目标,基于复杂网络和图论理论,从水生态网络的结构和功能两个维度,选取表征网络结构韧性及功能韧性的指标,对长沙市水生态空间韧性进行评价,指出长沙市域内水生态网络整体连接度较好,韧性基础好,景观破碎程度可控,但长期的城市建设与发展导致城市内部水系连通受损,水网多样性水平低,网络功能单一,冗余设计不足,调控管理动态适应性不强。研究进一步提出基于韧性提升的长沙市水生态网络优化策略:加快修复自然水系廊道,疏通连接现有人工沟渠;重视推行生态节点与廊道“点轴式发展”与多功能复合利用模式;加强城市水网结构和功能的冗余度和模块化设计,提高水生态网络调控管理韧性,形成多途径灾害响应的动态调控机制。

Studying the optimization of urban water ecological network from the perspective of resilience and improving the resilience of water ecological space are the important ways to improve the overall resilience level of cities.Firstly,the article combines the objectives of resilient city with water ecological network,and proposes to construct the water ecological space of resilient urban from three dimensions:structural resilience,functional resilience,and regulatory management resilience.Secondly,taking Changsha City as a typical case and applying MSPA model and MCR model,this article identifies and constructs the water ecological network based on the"source-corridor-node".From the perspective of integration of complex network and graph theory,the evaluation index of network resilience is constructed from the structure and function dimensions,and indicators effectively reflecting the structural resilience and functional resilience of the water ecological network are selected to evaluate the resilience of water ecological space in Changsha.The results show that:The overall connectivity of the water ecological network is at good status,a foundation of resilience is preferable,and the landscape fragmentation is manageable,but the long-term urban construction and development damage the connectivity of the water system within the city,and lead to the low-level diversity and single function of the water network.Redundant design of the network is insufficiency,dynamic adaptability of regulation and management is weak.The study further proposes the optimization strategy of the water ecological network in Changsha based on resilience enhancement:speeding up the restoration of natural water corridors and dredging the connection of existing artificial ditches,attaching importance to the implementation of"point-axis development"and multi-functional composite utilization models of ecological nodes and corridors,enhancing the redundancy and modular design of urban water network structure and function,improving the resilience of the regulation and management and forming a dynamic regulation mechanism for multi-channel disaster response.