Flood disaster in the underground space——Blocked or unblocked
In late July 2021, Zhengzhou, China, suffered extreme rainfall which was rare in history. A large number of underground garages, shopping malls and tunnels in low terrain suffered stormwater intrusion, and part of the underground space has been affected severely. The rainstorm caused casualties and property losses, arousing deep reflection and discussion on public safety issues caused by extreme weather.
On August 4, the China Meteorological Administration issued the "China Climate Change Blue Book (2021)", stating that emergency response to extreme events will become the norm under the global warming trend. On August 6, 2021, the Conference on Disaster Prevention of Urban Underground Space was launched online, focusing on the prevention of disaster in underground space. Integrated landscape architecture, urban and rural planning, architecture, civil engineering, rock mechanics and other interdisciplinary fields, the conference aimed to exchange experience and discuss the direction of related theories and practices in the future.
As an integral part of the urban ecosystem, landscape architecture plays an important role in climate change mitigation and adaptation, and promoting the construction of low-carbon and resilient cities. Chinese landscape architecture advocates the integration of multi-disciplinary theory and practical experience, and proposes strategies for mitigating flood disasters in urban underground space. Topography, soil and vegetation are important means for landscape architects to regulate stormwater runoff and infiltration, which have a part in mitigating the impact of flood disasters on underground space. Though blocking the entrance is an effective means to prevent floodwaters from pouring into urban underground space, it is not the method of landscape design. Compared with blocking, landscape architecture advocates unblocking, which means to make the stormwater runoff gather in sunken green belt instead of urban underground space by changing the direction of stormwater runoff through the design of topography, vegetation and soil tightness.
Image Credits: Luo Dan
Due to its unique geographical location, underground space has become the vulnerable site for flood disasters. It is urgent and necessary to think about and propose strategies to mitigate flood disasters in underground space. Landscape architects should not only focus on the above-ground space, but also the underground space and the synergy between them, that they can influence and regulate the underground landscape through the design of the above-ground landscape.
Prof. Shao Jizhong is full professor of landscape architecture in Huazhong Agricultural University, associate department head, PhD, he leads his team to research in digital landscape architecture, urban planning, global climate change and carbon emissions issues.