Socioeconomic Factors Influence the Spatial and Temporal Distribution of Blue–Green Infrastructure Demand: A Case of Nanjing City

Blue–green infrastructure provides a variety of ecosystem services and is becoming an increasingly vital part of urban ecosystem protection. It is an ecological facility for ecological conservation and environmental protection, and a foundation for realizing people’s needs for a better life. This study selects indicators from four dimensions: social, economic, environmental, and ecological, and the demand for blue–green infrastructure is assessed comprehensively. The results show that: (1) the demand for blue–green infrastructure varies spatially with the development of the city; (2) the total demand for blue–green infrastructure in Nanjing from 2000 to 2020 shows a pattern of “high in the center and low in the periphery”; (3) the level of economic development, urban spatial pattern, and decision management orientation have different degrees of influence on the demand for blue–green infrastructure, with the urban spatial pattern having the greatest impact. Therefore, in the future, blue–green infrastructure should be optimized by taking into account the spatial characteristics of demand in Nanjing.