Decentralized urban systems
Introduction
Low Impact Development (LID) is a term used in Canada and the United States to describe the organization of land along with its approach to engineering design to manage stormwater runoff. The DBI emphasizes water conservation and the use of natural elements on site to protect water quality. This approach implements the design of small-scale hydrological controls to replicate the previous development of the hydrological regime of watersheds through infiltration, filtering, storage, evaporation and slowing runoff near its source.[1].
Equivalent terms used elsewhere include sustainable urban drainage systems (SUSD) in the United Kingdom (where DBI has a very different meaning), water-sensitive urban design in Australia, natural drainage systems in Seattle, Washington[2] and "Insitu Stormwater Management", as used by the Washington State Department of Ecology.[3].
Alternative to conventional stormwater management practices
A concept that began in Prince George's County, Maryland in 1990, DBI began as an alternative to improve traditional stormwater management practices installed on construction projects. Officials found that traditional practices such as detention ponds and retention basins were not cost-effective and that the results did not meet stated water quality goals. The Low Impact Development Center, Inc., a nonprofit water resources research organization, was formed in 1998 to work with government agencies and institutions to advance the science, understanding and implementation of DBI and other sustainable environmental planning and design approaches, such as green infrastructure and the Green Highway Partnership.
The DIB design approach has received support from the U.S. Environmental Protection Agency (EPA) and is being promoted as a method to help meet the goals of the Clean Water Act.[5] Several federal, state, and local agency programs have adopted DBI guidelines for land development and public works projects. DBI techniques play a very important role in smart growth and green infrastructure land use planning.