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Located in the southwest of Beijing along the Yongding River, this is a key area for the government to build a low carbon new town. The rainwater low impact development plan for this area is expected to improve flood resilience, targeting the retention and storage of floodwater to cope with a 50 year in 1 flood return period.
The drainage system will be a combination of best management practice (BMP), integrated ecology and conventional drainage planning. The design is mainly divided into three tiers: land parcel, street and basin. In the event o f a small rain shower most of the surface runoff will be stored and treated by parcel and street BMPs. In heavy rain events, overflow runoff is stored and treated by the basin BMP in both dry and/ or wet ponds placed in public open spaces. This will control the maximum discharge rate into downstream drainage channels or infrastructure drainage pipelines.
During the design process, various factors and aspects were considered, including rainfall runoff rate, soil characteristics, BMP sizing and layout, land use type, street category, typical section, drainage pipe capacity, vertical elevation design and landscaping.
The project rethinks the role of green infrastructure in urban living and demonstrates that urban surface runoff and pollution load can be controlled at-source in the parcels, at the street level and in downstream basins. It’s also a vivid illustration of enhanced natural environment and biodiversity with an integrated conventional and sustainable drainage system.
