The ancient urban water system construction of China: the lessons from history for a sustainable future

China is an agricultural-based country, but the documented urban history was dated back to more than 4,000 years. The early civilisations of China began in the mid and lower basin of Yellow River and Yangtze River. Being situated near the rivers, water supply was advantageous to the cities, but at the same time, they also faced flooding risk from the rivers. Accordingly, an urban water cycling system which includes water supply use and rainwater management, waste water management, river flood control, drainage and river transportation etc, in a city was achieved in ancient China. More especially, a perfect model of urban water system was formed at ancient Chang'an City, the capital of Han Dynasty (202 B.C.∼220 A.D.). Thereafter, it influenced the urban construction of water system in many ancient cities of China. Unfortunately, this water system has changed widely in China due to the current urbanisation, which brought obvious problems to the cities, for example, frequent rainstorm flood in many cities due to lack of complete drainage facilities. Therefore, the aim of this paper is to explore the urban water system construction in ancient China, and study the wisdom and lessons from history to ensure a sustainable future.