In China, the problem of water conservancy system has always been a major obstacle to urban development for cities at the downstream of the Yangtze River. In the rainy season, heavy rainfall often results in floods at the downstream of the Yangtze River. This does not only cause harm to people's lives and safety, but also brings huge economic losses. This book summarizes and analyses the causes as well as suggests solutions to solve these problems effectively and improve the sustainability of the city. Discussions and suggestions are made from the aspects of urban water conservancy system, smart flood adaptation and the construction of sponge cities. This study also investigates the results of China's pilot sponge city.