SOUTHEAST MICHIGAN LID TECHNIQUES

Rain Gardens

Rain Gardens (also know as bioretention cells) are shallow surface depressions planted with specially selected vegetation to capture and treat stormwater runoff. Rain gardens may be as simple as an enhanced swale in the backyard, or they may involve more extensive planning and engineering with a gravel storage layer and/or underdrains connected to municipal stormwater systems. In a rain garden, plants and soils filter storm water naturally, removing nutrients and other pollutants. Rain gardens can be integrated into various site layouts and can work well with other structural stormwater systems.

Additional links:
http://www.socwa.org/lawn_and_garden.htm
http://www.raingardens.org/Index.php
http://www.ltu.edu/stormwater/bioretention.asp
http://dnr.wi.gov/runoff/rg/

Green Roofs

A green roof is a living vegetated roof that captures and treat roof top run-off and provide significant environmental benefits. There are two basic types of green roofs – extensive and intensive. Extensive green roofs are 6 inches, or less, in depth and are typically design more for function (i.e. stormwater mitigation). Intensive green roofs are 10 inches, or deeper, and tend to be more pedestrian friendly. These are more familiar in the United States and include many urban landscaped plazas. Intensive assemblies can also provide substantial environmental benefits, but are intended primarily to achieve aesthetic and architectural objectives.

Additional Links:

http://www.ltu.edu/stormwater/greenroof.asp
http://www.greenroofs.org/
http://www.epa.gov/hiri/strategies/greenroofs.html
http://www.hrt.msu.edu/greenroof/
http://www.bae.ncsu.edu/greenroofs/

Porous Pavements

A porous pavement system consists of a permeable surface underlain by a storage reservoir to facilitate stormwater capture and infiltration. The permeable surface can consist of porous asphalt, porous concrete, concrete paver blocks, or reinforced turf. The storage reservoir may consist of a stone bed of uniformly graded and clean-washed course aggregate, 1-1/2 to 2-1/2 inches in size, with a void space of at least 40% or other pre-manufactured structural storage units.

Naturalized Areas

Naturalized Areas is a general term for actively incorporating or restoring sustainable landscaping practices that mimic natural conditions including a reduced dependence on watering and fertilization. These can be incorporated into existing stormwater BMPs, such as naturalized detention basins, but are more commonly found in the context of a riparian (or other specially protected) buffer areas. Native or naturalized areas includes the restoration of forest (i.e. reforestation), savanna, and/or meadow and the conversion of turf to meadow.

What is an LID Technique?

Low Impact Development (LID) is an innovative stormwater management approach with a basic principle to manage rainfall at the source using uniformly distributed, decentralized small-scale controls. 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. Techniques are based on the premise that stormwater management should not be stormwater disposal. Instead of conveying and managing / treating stormwater in large, costly, end-of-pipe facilities located at the bottom of drainage areas, LID addresses stormwater through small, cost-effective landscape features located at the lot level. Southeast Michigan Council of Governments and other member governments are active participants in LID and together formed the Southeast Michigan LID team, which provides a venue for implementing LID. The LID Techniques are versatile in treating urban redevelopments, new developments and also transportation corridors. LID has numerous benefits and advantages over conventional stormwater management approaches. It is a more environmentally and economically sustainable technology in addressing the adverse impacts of urbanization.

The benefits of LID include:

1. Improvement of community livability
2. Restoration of urban fisheries
3. Protecting sensitive habitats
4. Meeting regulatory obligations
5. Integrating local greenways initiative

Source: http://www.semcog.org/LowImpactDevelopment.aspx