Green infrastructure

Green infrastructure provides habitat, flood protection, cleaner air, and cleaner water. These systems use vegetation and soils to soak up and store stormwater.

Please be aware that green infrastructure measures need to be tailored to your property and, depending on the project, you may need to consult with an architect, engineer, or another expert. Check with your local planning and zoning office or building department before you start.

Downspout disconnection

This simple practice reroutes rooftop drainage pipes from draining rainwater into the storm sewer to draining it into rain barrels, cisterns, or permeable areas. You can use it to store stormwater and/or allow stormwater to infiltrate into the soil. Downspout disconnection could be especially beneficial to cities with combined sewer systems.

Rainwater harvesting

Rainwater harvesting systems collect and store rainfall for later use. When designed appropriately, they slow and reduce runoff, while also providing for landscaping, toilet flushing, and other non-potable uses. This practice could be particularly valuable in arid regions, where it could reduce demands on increasingly limited water supplies.

Rain gardens

Rain gardens are versatile features that can be installed in almost any unpaved space. Also known as bioretention, or bioinfiltration they are shallow, vegetated basins that collect and absorb runoff from rooftops, sidewalks, and streets. This practice mimics natural hydrology by infiltrating, and evaporating and transpiring—or “evapotranspiring”—stormwater runoff.

Green roofs

A green roof is a rooftop that is partially or completely covered with a growing medium and vegetation planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems. They reduce stormwater runoff, reduce the urban heat island effect, and provides habitat. Green roofs are particularly cost-effective in dense urban areas where land values are high and on large industrial or office buildings where stormwater management costs are likely to be high.

Planter Boxes

Planter boxes are urban rain gardens with vertical walls and either open or closed bottoms. They collect and absorb runoff from sidewalks, parking lots, and streets and are ideal for space-limited sites in dense urban areas and as a streetscaping element.

Bioswales

Bioswales are vegetated channels that provide treatment and retention as they move stormwater from one place to another. These vegetated swales slow, infiltrate, and filter stormwater runoff from paved areas. As linear features, they are particularly well suited to being placed along streets and parking lots.

Permeable Pavements

Permeable pavements infiltrate, treat, and store rainwater where it falls. They can be made of pervious concrete, porous asphalt, or permeable interlocking pavers. They reduce stormwater runoff, increase groundwater recharge, reduce the use of road salt, and reduce surface water ponding. This practice is well suited for alleys, parking lots, and walkways.

Green Parking

Many green infrastructure elements can be seamlessly integrated into parking lot designs. Permeable pavements can be installed in sections of a parking lot and rain gardens and bioswales can be included in medians and along the parking lot perimeter. Benefits include mitigating the urban heat island, reducing standing water, and providing a more walkable environment.

Green streets & alleys

Green streets and alleys are created by integrating green infrastructure elements into their design to store, infiltrate, and evapotranspire stormwater. Permeable pavement, bioswales, planter boxes, and trees are among the elements that can be used together to create a green street or alley.

Urban tree canopy

Trees reduce and slow stormwater by intercepting precipitation in their leaves and branches. Many cities have set tree canopy goals to restore some of the benefits of trees that were lost when the areas were developed. Some of the benefits of planting trees include: a reduction in the urban heat island, improved habitat, reduced stormwater runoff, and increased infiltration.

Land conservation

Poor water quality and flooding in urban areas can also be addressed by protecting open spaces and sensitive natural areas within and adjacent to a city while providing recreational opportunities for city residents. Natural areas that should be a focus of this effort include riparian areas, wetlands, and woodlands.