Rain gardens, bioswales, green roofs, permeable pavement, urban trees, runoff capture, infiltration, water quality, flood reduction, maintenance, and gray infrastructure
Green stormwater infrastructure
Green stormwater infrastructure uses plants, soils, and designed landscapes to slow, absorb, store, and filter rainwater close to where it falls.
What it means
Green stormwater infrastructure is a way to manage rain where it lands. Instead of sending all runoff straight into storm drains, it uses planted areas, engineered soils, gravel layers, storage space, and sometimes pavement that lets water pass through.
The basic idea
A city changes the water cycle. Roofs, streets, and parking lots shed water quickly, so rain becomes fast runoff. Green infrastructure gives that water places to slow down, soak in, evaporate, or be taken up by plants before it reaches a pipe or stream.
Common tools
Rain gardens and bioretention cells collect runoff in planted basins. Bioswales move water through shallow vegetated channels. Green roofs hold rainfall above buildings. Permeable pavement stores water below the surface, and street trees intercept rain before it hits the ground.
Green and gray together
This is not a complete replacement for storm sewers, culverts, and treatment plants. In most places, green and gray systems work together: green features reduce and clean frequent runoff, while conventional infrastructure handles overflow, conveyance, and larger design storms.
What it can remove
As water moves through soil and vegetation, sediment can settle out, some nutrients can be taken up or transformed, and metals or hydrocarbons may bind to soil particles. Performance varies with design, soil condition, season, and the pollutants present.
Where design matters
A rain garden beside a small parking lot has different needs than a curbside planter on a busy street. Engineers and landscape designers consider drainage area, soil infiltration, groundwater, utilities, winter salt, pedestrian access, overflow paths, and long-term maintenance.
Tradeoffs
Green infrastructure takes space and attention. Plants can fail, sediment can clog inlets, and poorly placed features may not drain well. The upside is that a well-maintained network can also add shade, habitat, calmer streets, and more attractive public spaces.
Why it matters
Stormwater is one of the main ways cities send pollution and sudden flows into local waterways. Green stormwater infrastructure helps treat runoff as part of the landscape, making water management more visible, distributed, and adaptable.