Green Infrastructure Practices
Some of these sections are being developed. New entries and links to existing entries may be added over time and as they become available
I. Planning Practices
Preservation of buffers – Define, delineate and preserve naturally vegetated buffers along perennial streams, rivers, shorelines and wetlands.
Reduction of clearing and grading – Limit clearing and grading to the minimum amount needed for roads, driveways, foundations, utilities and stormwater management facilities
Locating sites in less sensitive areas – Avoid sensitive resource areas such as floodplains, steep slopes, erodable soils, wetlands, mature forests and critical habitats by locating development to fit the terrain in areas that will create the least impact.
Conservation design – Use clustering, conservation design or open space design to reduce impervious cover, preserve more open space and protect water resources
Soil restoration – Restore the original properties and porosity of the soil by deep till and amendment with compost to reduce the generation of runoff and enhance the runoff reduction performance of post construction practices.
2. Reduction of impervious cover
Roadway reduction – Minimize roadway widths and lengths to reduce site impervious area.
Sidewalk reduction – Minimize sidewalk lengths and widths to reduce site impervious area
Driveway reduction – Minimize driveway lengths and widths to reduce site impervious area.
Cul-de-sac reduction – Minimize the number of cul-de-sacs and incorporate landscaped areas to reduce their impervious cover.
Building footprint reduction – Reduce the impervious footprint of residences and commercial buildings by using alternate or taller buildings while maintaining the same floor to area ratio.
Parking reduction – Reduce imperviousness on parking lots by eliminating unneeded spaces, providing compact car spaces and efficient parking lanes, minimizing stall dimensions, using porous pavement surfaces in overflow parking areas, and using multi-storied parking decks where appropriate.
II. Treatment Practices for Water Quality Volume
1. Area reduction practices
Conservation of natural areas, streams and wetland buffers – Retain the pre-development hydrologic and water quality characteristics of undisturbed natural areas, stream and wetland buffers by restoring and/or permanently conserving these areas on a site.
Vegetated buffer, filter strip and riparian reforestation – Undisturbed natural areas such as forested conservation areas and stream buffers or vegetated filter strips and riparian buffers can be used to treat and control stormwater runoff from some areas of a development project.
Vegetated open channel – The natural drainage paths, or properly designed vegetated channels, can be used instead of constructing underground storm sewers or concrete open channels to increase time of concentration, reduce the peak discharge, and provide infiltration.
Tree planting/tree box – Plant or conserve trees to reduce stormwater runoff, increase nutrient uptake, and provide bank stabilization. Trees can be used for applications such as landscaping, stormwater management practice areas, conservation areas and erosion and sediment control.
Rooftop and overland disconnection – Direct runoff from residential rooftop areas and upland overland runoff flow to designated pervious areas to reduce runoff volumes and rates.
Stream daylighting – Stream Daylight previously-culverted/piped streams to restore natural habitats, better attenuate runoff by increasing the storage size, promoting infiltration, and help reduce pollutant loads.
2. Volume reduction practices
Rain garden – Manage and treat small volumes of stormwater runoff using a conditioned planting soil bed and planting materials to filter runoff stored within a shallow depression.
Green roof – Capture runoff by a layer of vegetation and soil installed on top of a conventional flat or sloped roof. The rooftop vegetation allows evaporation and evapotranspiration processes to reduce volume and discharge rate of runoff entering conveyance system.
Stormwater planter – Small landscaped stormwater treatment devices that can be designed as infiltration or filtering practices. Stormwater planters use soil infiltration and biogeochemical processes to decrease stormwater quantity and improve water quality.
Rain tank/Cistern – Capture and store stormwater runoff to be used for irrigation systems or filtered and reused for non-contact activities.
Porous Pavement – Pervious types of pavements that provide an alternative to conventional paved surfaces, designed to infiltrate rainfall through the surface, thereby reducing stormwater runoff from a site and providing some pollutant uptake in the underlying soils.