Constructing a water ecological security pattern in sponge cities utilizing machine learning and geographic information systems

The objective of this study is to enhance urban water security, maintain the ecological balance of water, and leverage the role of water resources in the development of sponge cities. By selecting a city as the research subject, we analyze the components of the urban water ecological security pattern, taking into account the characteristics of the natural-social dual water cycle during urbanization. Employing geographic information system (GIS) and remote sensing technology, we construct a single-element water ecological security pattern that covers four critical dimensions: rainfall and flood management, soil and water conservation, water resource conservation, and water quality. Based on the principle of inherent consistency, a comprehensive assessment security pattern for the urban water cycle is established. The study then delves into the regional water cycle phenomenon using the Soil Conservation Service (SCS) model. Rainfall erosivity is determined through the regression equation for rainfall and the R factor, as proposed by Renard. The water quality balance method is employed to calculate regional water savings, while the water quality detection method is used to assess the water quality index of the water environment. The findings reveal that areas with low water ecological security constitute 18.87% of the study area, predominantly surrounding reservoirs, wetlands, and lakes where water sources are relatively plentiful and vegetation coverage is high. Medium-level water ecological security areas, making up 12% of the region, are mainly found in areas of higher elevation, such as the north, southwest, and southeast, with predominant land types being hills, woodlands, and grasslands. High-level water ecological security areas account for 17.29%, largely concentrated in areas with robust flood control measures and are mostly located in flat regions such as the west, east, and south of the urban district, where cultivated land and residential areas prevail. The purpose of this investigation is to provide a scientific reference and foundation for mitigating the urban water ecological crisis, promoting the sustainable utilization of urban water resources, and protecting the regional ecological environment.