Abstract: This paper studies the design method of urban constructed wetlands in sponge city construction,characterizing the important role of constructed wetlands in purifying rainwater in sponge city construction. When the treatment capacity of the constructed wetland in the renovation project is lower than the designed water volume,enhanced treatment facilities should be added at the front end of the wetland to meet the requirements of reducing pollution load,reducing SS,reducing wetland blockage,and deep rainwater purification. After internal structural design and reasonable optimization of various process sections such as pre-enhanced treatment facilities,stabilization ponds,subsurface wetlands,surface flow wetlands,and outlet ponds,constructed wetland projects could effectively reduce the rainwater pollution load in sponge city construction. The effluent quality of constructed wetlands varies with the rainwater load of the pumping station,showing the characteristics of unstable water quality. It is recommended to take appropriate measures to reduce the rainwater treatment capacity to ensure compliance with discharge standards.

Key words: sponge city, constructed wetlands, design method