Low Impact Development
What is LID? Low Impact Development is an approach to environmentally friendly land use planning. It includes a suite of landscaping and design techniques that attempt to maintain the natural, pre-developed & developed ability of a site to manage rainfall. LID techniques capture water on site, filter it through vegetation, and let it soak into the ground where it can recharge the local water table rather than being lost as surface runoff. An important LID principle includes the idea that stormwater is not merely a waste product to be disposed of, but rather that rainwater is a resource.
Where should LID be used? LID can be applied to new development, urban retrofits, and redevelopment / revitalization projects at many scales. At a small scale, LID techniques can be used to better handle rainfall for a single family lot through rain barrels and rain gardens. At a larger scale, proper site design in combination with many landscaping and infiltration techniques distributed throughout a subdivision cumulatively improve rainfall and run off management.
Conventional Development vs. LID: Conventional development techniques often clear all trees and valuable topsoil from a site and re-grade it so that all water ends up in one large detention basin. Resulting problems include loss of recharge, increased water temperature, decreased water quality and higher runoff volumes.
What are the benefits of LID?
Stormwater Management: LID techniques can help us reduce runoff and non-point source pollution – our biggest source of pollution to water bodies.
Urban runoff and discharges from storm water outfalls are the single largest source responsible for water quality problems, in the Commonwealth’s rivers, lakes, ponds, and marine waters. (Massachusetts DEP Stormwater Policy Handbook, 1997)
Aesthetically Pleasing: LID practices are often more cost effective and aesthetically pleasing than traditional, structural storm-water conveyance systems.
Lower Maintenance: LID measures reduce municipal infrastructure and are therefore lower in maintenance than conventional, structural storm-water controls. (EPA Low Impact Development, a Literature Review, 2000). Many LID techniques can be maintained using traditional landscaping practices.
Cost Effective: LID techniques require less constructed infrastructure, increase the value of properties, reduce irrigation costs and often increase the number of units which can be developed on a site.