The Liyumen Waterway Park is a pilot project in Shenzen (Guangdong, China) that aims to transform a polluted greywater channel into a popular community resource by banking on symbiotic nature-based solutions.
The widespread implementation of flood protection measures in the past has transformed rivers into concretised channels, thereby eradicating ecological resilience. Moreover, untreated sewage flowing into these waterways is a serious health risk. The proposal by Beijing’s landscape practice Turenscape effectively tackles these problems in a holistic manner.
Through a step-by-step approach, the project transforms an inefficient drainage system into a green oasis. This project and its large-scale implementation are based on Turenscape’s concept of ‘sponge cities’, a measure developed to address and prevent urban flooding due to erratic rainfall patterns, attributed to climate change.
The existing channel is redesigned into a wide terraced wetland by removing concrete barriers and terracing the slope. Wastewater flowing into the waterway is cleansed biologically, allowing adjacent green spaces to be fertilised and irrigated.
The approach here builds on results from past experiments. Tests showed conclusively that 10 km2 of constructed wetland can cleanse 0.8 m3 of wastewater from grade V to III. The treatment slows down the speed of surface flows, increases detention and improves flood resiliency by 36%. It also saves 70% of energy that would otherwise have been used for mechanical treatment.
By converting infrastructural spaces into green ones, this project enhances the livability of the city, infusing vitality into what was once a monotonous landscape. It will be a space of retreat for the new central business district for 700,000 daily inhabitants and employees.
The vegetation also mitigates temperature spikes during hot summers or that are due to the heat island effect.
The project is funded by the government to showcase solutions to stormwater management and wastewater recycling. It provides a vital ecosystem that enhances the quality of life for local communities.
The approach to blue-green restoration in the Waterway Park was already adopted as a national policy in China in 2013. This led to prioritising large-scale nature-based infrastructures such as wetlands, greenways, parks, green roofs, permeable pavements and bioswales.
The project by Turenscape’s director Kongjian Yu was awarded an acknowledgement prize in the 2020 Asia Pacific leg of the Holcim Awards. Check out the Ecogradia podcast episode — season 1, episode 5 — with Yu, where he talks about his work.
Post sponsored by the Holcim Foundation for Sustainable Construction
A Frontline project is holistic, net-zero/net-positive and integrative. It protects or regenerates a combination of social, ecological and economic systems, aiming for a ‘greater-than-sum-of-parts’ outcome.
Under the Köppen climate classification, these are ‘C’ climate types. Temperate climates have mild winters and summers where the average in the warmest month is higher than 10° C and the coldest does not drop below 0° C. This climate is common in coastal regions.
Greenhouse gases are sequestered by about 2,491 tons per year.
The cooling effect is equivalent to the power of about 145 domestic air conditioners, saving 3,840 kWh of electricity per day, the equivalent to 724 tons of carbon emissions per year — Shenzhen use air-conditioning for 8 months per year.
The wetland cleanses about 5.1 km3 of pre-treatment wastewater per day, saving energy for sewage treatment plants by at least 5,000 kWh, thereby reducing carbon emissions by 1,500 tons annually.
Rehabilitated vegetation sequesters greenhouse gas emissions by at least 267 tons per year.
The use of waste concrete to make planters eliminates the need for 735 tons of stone, thereby avoiding carbon emissions by 78 tons.