How to understand the concept of sponge city

I think it is clearer to understand according to the above picture. Sponge city is also known as "low-impact rainwater development system" internationally, which mainly includes seven aspects:

Popularize building rainwater collection and utilization and roof greening technology; Increase the absorption of rainwater by road green space; Newly-built urban roads increase water permeability (bright solid color permeable integral pavement); New large-scale public service facilities supporting rainwater collection and utilization; Ecological space necessary to maintain urban water cycle; Rainwater must be purified by the coastline; Strictly control the exploitation of groundwater.