Sponge city concept reimagines urban water management through natural water cycle restoration reducing surface runoff by 70-80%. Green infrastructure components including bioswales, permeable pavements, green roofs, & constructed wetlands enable water infiltration, treatment, & storage. Integrated water management systems coordinate stormwater, wastewater, & drinking water enabling circular water economies. Global examples including Wuhan, Copenhagen, Singapore, Portland, & Melbourne demonstrate sponge city design's transformative potential.