Low Impact Development (LID)

Low impact development is defined as an innovative stormwater management approach with a basic principle that is modeled after nature: manage rainfall at the source using decentralized micro-scale strategies, i.e. rain gardens, green roofs, and permeable pavements. LID's goal is to mimic a site's predevelopment hydrology by using design techniques that infiltrate, filter, store, evaporate, and detain runoff close to its source.  A critical paradigm shift must take place in order to accept and integrate this approach into the mainstream of stormwater engineering and management. Historically, stormwater management equated to stormwater disposal.  With LID, stormwater is managed as a resource rather than a liability.

• LID helps manage both stormwater quality and stormwater quantity.
• LID improves water quality. Concerns arise when stormwater runoff collects sediments, nutrients, acids and salts, heavy metals, toxic chemicals, and pathogens. Increased water temperature is also a major water quality concern.
• LID is simple and effective. It results in hydrologically functional landscapes that generate less surface runoff, less pollution, less erosion, and less overall damage to lakes, streams and coastal waters.
• LID is economical. It costs less than conventional stormwater management systems to construct and maintain while offering/enhancing quality of life.
• LID is flexible. It offers a wide variety of structural and nonstructural techniques in a wide variety of sites to provide for both runoff quality and quantity benefits.
• LID is a balanced approach. It is an advanced, ecologically-based land development technology that seeks to better integrate the built environment with the natural environment.
• LID was pioneered in Maryland in 1985 to address economic and environmental issues associated with water quality concerns in Chesapeake Bay. Since then, the concept of LID has been accepted and implemented to varying degrees nationwide.

What LID Looks Like:

There are many ways LID concepts can be incorporated into your home or be a design standard to follow during larger scale projects.  The most common strategies for LID include rain gardens, bioretention gardens, bioswales, pervious pavements, green roofs, and rain harvesting.  Click on the LID project type below to learn more on it.