There’s new evidence that filtering rainwater in an eco-friendly way saves money and helps the environment. More than 400 case studies of green rainwater projects detail the benefits of collecting water and filtering it naturally before it reaches waterways as polluted runoff. Green filter methods like rain gardens, green roofs and bioretention all help to convert urban stormwater into a valuable resource for communities.
A database of the 479 case studies has just been released by the American Society of Landscape Architects (ASLA). The studies show how the green infrastructure can can improve the quality of water in cities and towns and lower development costs by doing away with expensive, hard-runoff treatment options. The case studies show the projects have the potential to save communities millions of dollars a year.
Many of the projects are redevelopment or retrofits that return unproductive space and land to the public. In Georgia, a brownfield site was turned into a public park and a deteriorating playground was turned into a recreation area that captures and filters stormwater. One project in California includes vegetation planted on the roof of a three story apartment building to keep polluted runoff out of local waterways. Architects also designed what are called ‘bioswales’ where sloping drainage areas are planted with vegetation to remove silt and pollution from runoff water.
The Environmental Protection Agency asked the ASLA to collect case studies on projects that manage stormwater in a sustainable way. The studies not only showcase landscape architecture but show policymakers the value of promoting green infrastructure policies.