Assessment of Urban Rain Gardens Within Climate Change Adaptation and Circularity Challenge

Decreasing permeable surfaces in cities due to growing population and more frequent high-intensity rainfalls due to climate change lead to floods. The consequences are loss of freshwater resource, disruption of natural water cycle, and sewer outflow and spread of untreated wastewater into the environment. Adaptations to decrease the vulnerability of cities to heavy rainfalls need to integrate solutions that have a circular perspective. Nature-based solutions (NbS) can be helpful to adapt urban infrastructure to align with circular cities that are more sustainable. Rain garden, which is one of the best management practices suggested to manage stormwater, can provide many hydraulic benefits such as surface runoff volume reduction, peak flow reduction, and flow mitigation. Therefore, it can reduce the stress on the stormwater infrastructure. At the same time, it acts as a treatment tool by removing the pollutants from rain water. Furthermore, it provides a recharge area for groundwater where runoff percolates into the subsurface. Apart from these, a rain garden offers several solutions to mitigation of urbanization and global warming, such as reducing heat island formation and carbon footprints and supporting biodiversity. This study reviewed the literature to quantify contributions of rain gardens to mitigate the impacts of climate change and enhance circularity in cities.