Stormwater management
Stormwater management is the planning and control of rainwater runoff to reduce flooding, pollution, erosion, and damage to waterways and property.
Infiltration: The movement of water from the ground surface into soil. Infiltration reduces runoff by letting rainwater enter the ground.
Green infrastructure: A network of natural and engineered features that manages water and supports environmental benefits. Stormwater planning often combines these features to manage runoff near where it falls.
Urban flooding: Flooding in built-up areas caused by rainfall, river overflow, coastal water, or drainage failure. Runoff controls can reduce flooding when rainfall exceeds drainage capacity.
Sustainable drainage system: A drainage approach that manages rainfall close to where it falls using natural processes and engineered features. This approach emphasizes local retention and treatment rather than rapid conveyance.
Detention basin: A basin that temporarily stores stormwater and releases it at a controlled rate. Temporary storage reduces peak flows reaching downstream channels.
Rain garden: A planted depression that collects runoff and promotes infiltration and pollutant removal. Rain gardens manage runoff from roofs, streets, and other small drainage areas.
Combined sewer overflow: A discharge of untreated wastewater and stormwater from a combined sewer during heavy rainfall. Reducing stormwater entering combined sewers can lower overflow frequency and volume.
Gray infrastructure: Conventional built water infrastructure, including pipes, culverts, and concrete channels. Gray systems convey runoff efficiently, while stormwater plans may also prioritize infiltration and ecological treatment.
Retention basin: A basin designed to hold stormwater permanently, often with a pool between storms. Permanent pools retain runoff and allow settling, infiltration, or reuse.
Permeable pavement: Pavement that lets water pass through openings or a porous surface into underlying layers. It reduces runoff from parking lots, paths, and other paved areas.