Advances in the blue-green space evaluation index system

Blue-green spaces composed of water and green spaces have certain ecological, economic, and social benefits for urban development. Many evaluation index systems have been developed to evaluate the health status of urban ecosystems. However, in these evaluation index systems, blue and green spaces are separately evaluated without considering the synergistic effect between water and green spaces in the ecosystem, thus affecting the unified planning and construction of cities. Therefore, based on existing studies, the development process of the blue-green space evaluation index system is divided into three stages: supply service evaluation stage, adjustment service evaluation stage, and cultural service evaluation stage in order to deeply discuss the development path of the blue-green space evaluation index system. The single blue and green evaluation index systems are compared from the perspectives of index selection and evaluation content. Moreover, the characteristics of conventional evaluation methods are discussed in order to propose an applicable evaluation index system and evaluation method of blue-green spaces for evaluating the degree of blue-green integration of cities. The review provides the basis for urban planning and ecological restoration.