Cities are full of buildings, sidewalks and streets that accumulate stormwater when it rains. This causes flooding, and also prevents rainwater from soaking into the ground. Green infrastructure, like this rain garden in Portland, Oregon, gives rain water somewhere to go. Native plants, mulch, and soil help to filter pollutants out of stormwater while providing habitat for birds, butterflies, and other pollinators. Source: Kendall Barbery
Green infrastructure solutions, such as green roofs, rain gardens, and porous pavement, help to reduce runoff by capturing and managing rain water where it falls, filtering out pollutants, and restoring the natural hydrologic cycle. But green infrastructure accomplishes more than just reducing runoff!
Adding canopy cover and native plants to cities helps to mitigate the impact of the urban heat island effect, provides important habitat for birds, bees, and other pollinators, and brings new life to urban neighborhoods and streetscapes. Green roofs also provide a range of benefits, from converting underused roof acreage into aesthetic and (occassionally) urban agricultural amenities, to extending the lifetime of the roof, and insulating the building below. Porous pavements, while not green in color, are exceptionally efficient at capturing and filtering runoff and reducing peak flows during storms.
Follow the images links to learn more about some of the green infrastructure solutions to stormwater runoff.