Quantitative Analysis of Sponge City Construction and Function in the Main Urban Area of Chengdu

This study utilizes ArcGIS, the InVEST model, and the SCS model to analyze remote sensing data from the central urban areas of Chengdu. The analysis simulates water yield and runoff within the study area while calculating the water conservation capacity for each land use type using the water balance method. This study aims to address the challenges faced by Chengdu in implementing its sponge city initiatives. The results reveal that the spatial distribution of direct runoff generally follows a pattern of “low in the periphery and high in the center”. Transportation, commercial, industrial, and residential land types account for 74.7% of the total surface runoff within the study area, emphasizing their importance in urban rainwater management and sponge city development. Water yield varies across different land use types, with water bodies exhibiting the lowest capacity and artificial land exhibiting the highest capacity. This pattern initially exhibited a downward trend before increasing, with land use type, climatic factors, and vegetation coverage identified as the primary drivers of water yield. The water conservation capacity of the study area gradually decreased, with higher values observed in the east and south and lower values in the north and west. These trends and spatial differences can be attributed to urban expansion and alterations in land cover. Based on these findings, this study assessed the risk of urban waterlogging and provided recommendations for optimizing low-impact development (LID) strategies. This study provides a scientific foundation for the development of sponge city initiatives, urban waterlogging mitigation, and rainwater management strategies in Chengdu.