Swift growth, albeit a strong suit of urban dynamism, often results in poorly constructed cities. In addition to a number of difficulties that cities in the U.S. are facing, more cities are suffering from urban storm flooding due to the lack of resilient infrastructure. Using engineered green spaces, a team at MIT is working to create cities that can optimize stormwater to deliver ecosystem benefits.
Urban storm flooding is increasingly becoming a problem in cities that do not have the infrastructure to deal with it, preventing cities’ natural ecosystems from taking their course. During urban growth, these ecosystems are often covered by pavement, trapping storm water on the surface. While on the surface, the water picks up trash, metal, and industrial waste that eventually flows back into urban water supplies.
In an attempt to instigate the ecosystem’s natural processes, a team at MIT has designed engineered green spaces that contain simple basins and serpentine wetlands to control water circulation and purify storm water. The project’s findings, which were released in a report titled “Design Guidelines for Urban Stormwater Wetlands,” was produced in partnership with MIT’s Abdul Latif Jameel World Water and Food Security Lab (J-WAFS) and supported by the MIT Norman B. Leventhal Center for Advanced Urbanism (LCAU) at MIT’s School of Architecture and Planning.
The wetlands’ design and guidelines detailed in the report combine engineering, urban planning, and landscape architecture to create a dynamic green space. These modular spaces, which make up of a number of clustered islands, can also be used as a recreational space and to replicate other natural habitats in the communities that they exist.
Monitoring and controlling the flow of water in the wetlands is necessary to give the city’s ecosystems a chance to improve the quality of the water. Wetlands naturally purify water through several biological and chemical processes.
In order to prove that the wetlands are compatible with different cities, the MIT team looked at Houston and Los Angeles as case studies. The project’s lead researcher and lead author Celina Balderas Guzmán said to MIT News: “We picked L.A. and Houston because they are both large cities in warm climates, rapidly growing, mostly suburban, with good prospects for green space.”
The team’s research was made available for free in order to encourage other urban planners and policy-makers to adopt the wetlands’ design. To develop the design, researchers tested more than 30 different designs to make them as dynamic and adaptable as possible. The accessibility of this research and the wetlands’ dynamism is also crucial to encouraging cities to adopt the model.
In 2015, the Chinese government announced the ‘Sponge City Initiative‘ – a plan to retrofit Chinese cities using a similar wetlands’ model. In the Sponge City Initiative, wetlands are designed to store excess rainfall, which is then used to irrigate gardens as well as rooftop gardens in an effort to channel rainfall more efficiently and address urban flood management. The Sponge City Initiative has also laid out plans to install permeable pavements to capture excess water and restore depleting groundwater reserves.
Last month, Slovenia touched upon the difficulties that its capital city Ljubljana faces with controlling urban storm flooding at the 16th Venice Biennale in their pavilion titled “Living with Water.” To help solve the problem, the city proposed alternative configurations to Ljubljana’s urban planning to allow the city’s natural ecosystems to treat excess urban storm flooding.