stormwater outlets
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Stormwater Outlets. Effectiveness of the Options. Stormwater Outlets. Several options are available, such as the infiltration basins under the parking lots on campus. - PowerPoint PPT PresentationTRANSCRIPT
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.
Total Phosphorous Removal Rate
(%)
Total Nitrogen Removal Rate
(%)
Total Suspended Solids Removal
Rate (%)
60 30 90
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.
Total Phosphorous Removal Rate
(%)
Total Nitrogen Removal Rate
(%)
Total Suspended Solids Removal
Rate (%)
30 30 60-80
Vegetative Cover Adopted TSS Removal Rate
Turf Grass 60
Native Grasses, Meadow, And plated
Woods
70
Indigenous Woods 80
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.
Total Phosphorous Removal Rate
(%)
Total Nitrogen Removal Rate
(%)
Total Suspended Solids Removal
Rate (%)
50 30 90
http://www.thcahill.com/wetlands.html
Infiltration Structures
• 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.
Total Phosphorous Removal Rate
(%)
Total Nitrogen Removal Rate
(%)
Total Suspended Solids Removal
Rate (%)
60 50 80
http://clean-water.uwex.edu/plan/drbasins.htm
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