Green infrastructure has many different pseudonyms: stormwater best management practices (BMPs); low impact developments (LIDs); or even sustainable urban drainage systems (SUDS). All of these acronyms indicate systems that aim to restore a site’s natural hydrology by improving the storage, infiltration, treatment, and capture of stormwater onsite.

Most—but not all—green infrastructure focuses on increasing urban green space, with a particular emphasis on native vegetation. All green infrastructure requires careful maintenance for optimal long-term performance. Some examples of green infrastructure include:

• Rain garden: a depression in the ground planted with native vegetation. Designed to store, treat, and infiltrate water on a typically small scale.
• Bioretention cell: similar to rain gardens in design but often contains additional storage capacity in gravel below the level of the planting medium. Can be used for larger-scale treatment than rain gardens. Depending on the bioretention cell’s design, may be appropriate for nitrate removal.
• Green roof: a layer of vegetation planted over the top of a waterproofing membrane installed on top of a flat (or gently sloped) roof. Green roofs provide different benefits in terms of building energy use reduction, air quality, and flood management, depending on the depth of the planting medium and the types of plants selected. Native plants are encouraged, as is vegetation that requires minimal maintenance.
• Rain barrel: captures water from roof gutters for storage and later reuse. Many rain barrels are designed for outdoor applications, though some can be fitted for indoor usage, such as flushing toilets.
• Bioswale: vegetated channels designed to slow, treat, and infiltrate runoff while safely conveying excess runoff storm sewer inlets or surface waters.
• Permeable pavement: a paved surface designed to infiltrate water into the ground rather than producing runoff. Water infiltrated into the pavement is often stored in a gravel underlayer and released slowly over time or infiltrated into the ground. Permeable pavements may be specially designed permeable materials (e.g., permeable asphalt or permeable concrete) or pavers interspersed with permeable fill between them.