French architect Jean-Pierre Pranlas-Descours and his team lead this Holcim Awards winner, in association with the French Scientific & Technical Building Centre (CSTB). The proposal for sustainable urbanisation 50km south-east of Lanzhou in China will preserve both traditional villages and agrarian land. It also offers new water-management solutions in an increasingly arid area.

Intensive urbanisation causes vegetation loss and exacerbates desertification. The development proposed by Jean-Pierre Pranlas-Descours offers a sustainable alternative to conventional urban planning. To counter the fragmentation and gradual loss of agricultural land in the Nanhe River valley, the project develops six “metropolitan villages” over 11 square kilometres and will intersperse farmland and traditional villages into its hybrid urban plan.

Reinventing the rules of urban development

The Yuzhong regional government and Chinese Society for Urban Studies commissioned Jean-Pierre Pranlas-Descours and his team to implement their vision in the north-western province of Gansu. The project is part of a national scheme to develop eco-cities and experiment with different urban design approaches.

By alternating urban housing with agricultural plots, the large residential project will preserve the rural heritage of this agrarian valley while offering a new philosophy of housing development that integrates nature and the water cycle into its blueprint. In bringing together traditional spaces with sustainable urban planning, the development will ultimately safeguard valuable farmland that might otherwise have been lost, when higher crop yields are needed as cities continue to encroach on arable land.

Making water-management a priority

The project also aims to address the issue of water scarcity in the region. Thirty years ago, the two arid mountains flanking the valley were green with trees. Deforestation has caused the land to become drier, reducing the rate of rainwater absorption. As a result, the natural water reservoirs are gradually disappearing and the only way of finding more aquifers is to keep drilling deeper.

As a response to water scarcity, the project includes an extensive irrigation system to supply the agricultural fields through a network of canals that will redistribute rainwater collected from rooftops and the surrounding hills. A system of ultra-light honeycomb structures (dubbed SAUL for “Structures Alvéolaires Ultra Légères”) will be deployed at the foot of the mountains as an artificial reservoir for local agriculture. The team of architects and engineers estimate that the device will collect up to one million cubic metres of water each year.

Although building was postponed due to the pandemic, Jean-Pierre Pranlas-Descours is optimistic that the project will soon begin implementation and take five years to complete. Residents support the plan, which will combine tradition and modernity.

Read the full interview:

“Metropolitan Villages” in Sixth Holcim Awards