Low Impact Development (LID) is a type of smart growth that simultaneously conserves green space and manages stormwater effectively. Unlike traditional land use designs, LID promotes natural stormwater management techniques that minimize runoff and help prevent pollutants from getting into the runoff. In some cases, these practices decrease the size of traditional retention and detention basins and can be less costly than conventional stormwater control mechanisms.
Examples of LID strategies include:
Conserved Green Space
Natural terrain protects soils from disturbance and compaction.
Hard, yet penetrable, surfaces reduce runoff by allowing water to
move through them into groundwater below.
Reduced Roadway Surfaces
Reducing roadway surfaces results in more permeable land area.
Disconnected Impervious Areas
Separate localized detention areas help limit the velocity and amount of water that must be handled by end-of-pipe water quality and quantity facilities.
An alternative to curb and gutter systems, vegetative swales convey water, slow runoff, and promote infiltration. Swales may be installed along residential streets, highways, or parking lot medians.
Green / Eco-roof Systems
These systems can significantly reduce the rate and quantity of runoff from a roof and provide buildings with thermal insulation and improved aesthetics.
Basins & Rain Gardens
Small vegetated depressions in the landscape collect and filter stormwater into the soil.
Concentrating structures to smaller areas preserves more open space and natural areas to be used for recreation, visual aesthetics, and wildlife habitat.
Surface ponds, underground catchment devices, or surficial aquifers store rainfall for future irrigation reuse. Smaller scale reuse systems include cisterns and rain barrels.
Stormwater ponds do not need to be “big muddy ponds.” They should include a variety of wetland plants and topography that promote natural water treatment.