Research on Sponge Transformation and Renewal Design of Old Residential Districts in Mountain Cities from the Perspective of Resilience

Developing sponge transformation of old communities in mountainous cities from the perspective of resilience is an important means of urban waterlogging control. Based on the Xibei community site in Huaxi District, a total of 8 indicator items are constructed from three aspects: community ecological environment, community safety, and community resources. The entropy weight method and TOPSIS method are combined with SWMM software runoff simulation to construct a sponge construction evaluation system for update design research. The research shows that the two key factors to improve the sponge construction index of old communities are the average catchment area and the permeable pavement rate; Taking the elevation difference of mountainous communities as the runoff buffer area, setting linear fine seam drainage ditches, vegetation shallow ditches with small dams, and permeable pavement can absorb more than 20% of peak runoff, and reduce the comprehensive runoff coefficient of the site by more than 50%; The division of community catchment area should be flexibly adjusted according to the slope of different areas; The site pavement renewal based on LID control can reduce the comprehensive runoff coefficient of the site by more than 40%, and the peak value of road rainstorm runoff can be reduced by more than 20%; The evaluation system can provide more targeted guidance for sponge transformation design.