Abstract: On the basis of summing up problems in current construction of sponge city, an idea of sponge city construction with underground reservoir system as city sponge is put forward. In line with the theory of sponge city, the holistic structure of underground reservoir system is described with seven systems as supporting project involving seepage, stagnation, storage, net, use, and discharge. The water circulation path of sponge city is dominated by such underground reservoir system. The sponge city project with urban water system as its core is of evident benefit for improvement of flood and water-logging control capacity, efficient utilization of water resources, and restoration of urban water ecological environment. The research provides a feasible technical support and effective guarantee of sound water circulation for sponge city construction.

Key words: sponge city, underground reservoir, stormwater management, systems engineering, flood and water-logging control, efficient utilization of water resources, ecological management