Green infrastructure is any practice that uses or replicates natural systems to achieve the desired outcome. This includes green roofs, bioswales and rain gardens. Green roofs replicate meadows to retain water and restore habitats on the top of buildings. Green infrastructure does not exclusively mean vegetation. Permeable surfaces are considered green infrastructure as well, because they handle rainfall the same way natural landscapes do. Green infrastructure looks to nature for advice, restoring and replicating ecological systems to create human benefits.