Low Impact Development (LID), often referred to as Conservation Development, combines a number of design, pollution prevention and treatment Best Management Practices (BMPs) to minimize the amount of untreated storm water runoff leaving a site. More than a treatment, LID is a design strategy to match the pre-development and post-development storm water runoff conditions as closely as possible. Innovative planning can result in a site yielding the same number of houses or buildings but with significantly less impervious area. What results is an area with increased infiltration and decreased storm water runoff.
Conservation design or LID design employs concepts like clustering, where buildings are situated closer to one another, which leaves more area for greater common green space. The design still yields the same number of structures and lots but they are designed to maximize protection of the stream and maintain areas that provide important natural functions.
BMPs like vegetated filter strips, porous pavement, bioretention areas and vegetated rooftops are often included in a Low Impact Development design. Rather than utilizing just one BMP, Low Impact Development employs multiple BMPs to achieve the most substantial water quality benefit.
Some additional benefits of Low Impact Development include reduced land clearing and grading costs, a potential reduction in infrastructure costs, increased lot and community marketability, and a reduction in impacts to local terrestrial and aquatic ecosystems. Savings on infrastructure can be shown in a reduction in street lengths, sidewalks and lengths of sewers.
In short, Low Impact Development allows for the full development of the property with reduced associated costs. While Low Impact Development concepts are still rather new, they provide an effective alternative for those wishing to explore the connection between development and environmentally-conscious design.
Additional information regarding Low Impact Development can be obtained from the following suggested resources:
Low Impact Development Center
Center for Watershed Protection
Low Impact Development Urban Design Tools
U.S. EPA Low Impact Development Page
U.S. EPA Green Streets Guide (PDF, 5.7 MB)