Nature-inspired stormwater management practice : the ecological wisdom underlying the Tuanchen drainage system in Beijing, China and its contemporary relevance

There are many outstanding constructions in ancient Chinese cities that are still in use in their unique local landscapes. An example of successful ecological engineering is the Tuancheng drainage system in Beijing. This paper presents a technical analysis of this drainage system and describes a hydrological model built in Stella® for a one-time rainstorm event and for annual water balance analyses. The results demonstrate how well the drainage criteria were chosen and prove that the implementation was exceptionally successful. An example of smart design solutions is the underground circular C-shaped drainage system in the terrace, where at each turning point, there is a pit to collect rainwater. In addition, the inverted paving by trapezoidal bricks and soil improvements contributed to the rapid infiltration of rainwater. During intense rainstorms, the system effectively attenuated stormwater and increased the infiltration rate. During drought conditions, such as in 1965, with only 226 mm of rainfall, the system increased soil water retention by 27 mm. The Tuancheng drainage system is an excellent example of an engineering solution managing drainage and storage, on- and underground, and using gray and green infrastructure to create a hydrological landscape functionally equivalent to natural conditions. Exploring ancient wisdom and using the ideas of our ancestors can help us to find more effective and efficient strategies to manage urban stormwater.