Stormwater Outlets Effectiveness of the Options
Stormwater Outlets • Several options are available, such as the infiltration basins under the parking lots on campus. • Pollutants must be considered when dealing with stormwater. The guidelines call for New Jersey call for suspended solids to be reduced by at least 80%, and for nutrient content to be reduced by the maximum feasible amount. • Rooftop runoff is considered “clean,” and can therefore be dealt with through different strategies that don’t remove pollutants.
Bioretention Cells • Use native plants and organic layers to filter stormwater as it infiltrates into the ground. • Native plants have the added benefit of requiring less maintenance and watering. • A list of native plants can be found at http://www.georgian.edu/pinebarrens/ • Can be easily added to existing buildings. • Cost efficient. http://www.epa.gov/owow/nps/bioretention.pdf
Rain Gardens and Stockton • Stockton is an ideal environment to become a leader in bioretention research. • The sandy soils in the Pinelands facilitate quick drainage. • Relatively uniform topography would help keep construction costs down, as well as provide numerous areas to perform research. Raingarden in the Pinelands http://www.icdc.com/~larsende/land.htm
Vegetative Filters • Areas of vegetation designed to remove pollutants from runoff. • Stormwater must enter and flow through filter as sheet flow for effective removal capabilities. • Design must incorporate an evenly graded slope, determined by both the vegetation and soil type. • Indigenous plants are most effective.
Constructed Stormwater Wetlands • Designed to handle runoff from areas from 10 to 25 acres. • Remove high percentages of pollutants. • Provides new habitat for wildlife. • Not suitable in areas of existing wetlands. http://www.thcahill.com/wetlands.html
Infiltration Structures http://clean-water.uwex.edu/plan/drbasins.htm • Designed to allow stormwater to recharge groundwater while removing pollutants. • Must be designed to drain within 72 hours to prevent water quality and mosquito problems. • Should not be used in areas with high levels of pollutants, to prevent contamination of groundwater.
Pervious Paving • Used to decrease runoff from paved areas. • Suitable for light duty applications, such as parking lots and sidewalks. • Can be used to decrease demand on other structural systems. http://www.psat.wa.gov/Publications/LID_studies/permeable_pavement.htm
Dry Wells • Dry wells are specialized infiltration structures designed to recharge groundwater with clean roof runoff. • They do not remove pollutants, so they cannot be used to handle other stormwater. http://www.njstormwater.org/tier_A/pdf/NJ_SWBMP_9.3%20print.pdf
Green Roofs • Vegetative cover on roofs of buildings. • Can reduce runoff by up to 75%. • Have the added benefit of adding to the heating and cooling efficiency of the building. http://www.hrt.msu.edu/greenroof/WebSite%20Images/19%20%20ChicagoCityHallAerial%2062703.jpg