Low Impact Development Overview

Low Impact Development Overview

The term low impact development (LID) refers to systems and practices that use or mimic natural processes that result in the infiltration, evapotranspiration or use of stormwater in order to protect water quality and associated aquatic habitat. 

EPA currently uses the term green infrastructure to refer to the management of wet weather flows using these processes, and to refer to the patchwork of natural areas that provide habitat, flood protection, cleaner air and cleaner water. 

At both the site and regional scale, LID/GI practices aim to preserve, restore and create green space using soils, vegetation, and rainwater harvest techniques.  LID is an approach to land development (or re-development) that works with nature to manage stormwater as close to its source as possible.  LID employs principles such as preserving and recreating natural landscape features, minimizing effective imperviousness to create functional and appealing site drainage that treat stormwater as a resource rather than a waste product. 

There are many practices that have been used to adhere to these principles such as bioretention facilities, rain gardens, vegetated rooftops, rain barrels and permeable pavements.  By implementing LID principles and practices, water can be managed in a way that reduces the impact of built areas and promotes the natural movement of water within an ecosystem or watershed.  Applied on a broad scale, LID can maintain or restore a watershed’s hydrologic and ecological functions. 


Nonpoint Source: Urban Areas

Urbanization increases the variety and amount of pollutants carried into our nation’s waters.  In urban and suburban areas, much of the land surface is covered by buildings, pavement and compacted landscapes.  These surfaces do not allow rain and snow melt to soak into the ground which greatly increases the volume and velocity of stormwater runoff.  In addition to these habitat-destroying impacts, pollutants from urban runoff include:

  • Sediment
  • Oil, grease and toxic chemicals from motor vehicles
  • Pesticides and nutrients from lawns and gardens
  • Viruses, bacteria and nutrients from pet waste and failing septic systems
  • Road salts
  • Heavy metals from roof shingles, motor vehicles and other sources
  • Thermal pollution from impervious surfaces such as streets and rooftops

These pollutants can harm fish and wildlife populations, kill native vegetation, foul drinking water, and make recreational areas unsafe and unpleasant.

 

 


Fact Sheets and Technical Reports

Link to fact sheets and technical reports.