Glossary of Low Impact Development Techniques

Low Impact Development (LID) uses a variety of techniques to control stormwater runoff at the source, instead of relying solely on conventional collection, conveyance, storage and treatment systems.

Rain gardens

Rain gardens or bioretention cells are vegetated areas that collect runoff so it can slowly infiltrate into the ground.  Some have special soil mixtures that maximize infiltration and pollutant removal but avoid extended ponding.

 

Cisterns and rain barrels

Cisterns and rain barrels harvest and store rainwater from roofs which provides "soft" chemical-free water for garden or lawn irrigation, reduces water bills and conserves municipal water supplies.

 

Green roofs

Green roofs or eco-roofs are covered with lightweight soils and plants. Used for decades in Europe, they mitigate the urban heat island effect, insulate the roof and extend its life and reduce energy costs.

 

Permeable or porous pavements

Pervious, permeable, or porous pavements allow water to soak through the paved surface into the ground. Examples are porous concrete and asphalt, grasscrete, gravel with plastic grid systems and interlocking paving bricks.

 

Vegetated Swales

Vegetated swales are broad, shallow channels hat reduce stormwater volume and velocity and filter pollutants from the water.

 

Smart Site Design

Smart site design conserves trees and habitat, minimizes disturbance and soil compaction, and integrates on-site stormwater management into the other considerations for site development.

 

Green Streets

Green streets replace conventional catch basins, pipes, curbs and detention facilities with vegetated swales, bioretention cells and/or pervious pavement.

 

Reduced Pervious Footprint

Narrow streets, multi-level structures reduce the impervious area that causes stormwater runoff.