Green Roofs: A Part of Green Infrastructure Strategy for Urban AreasThomas P. O’ConnorUrban Watershed Management Branch Edison, New Jersey

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Office of Research and Development July 31, 2013

Summary of PresentationSummary of Presentation• Brief Background• Extensive RoofsExtensive Roofs• Benefits• EPA Literature

Effect of Development onEffect of Development on Water Balance

New Sweden Colony in AmericaNew Sweden Colony in AmericaBridgeton, New JerseyRecreated farmstead 350th Anniversary of the New Sweden Colony in America

11 Acre Green Roof in GermanyRetains 90-95% Runoff

Green roof types

• Intensive roofs, designed for plant growth d (> 6 i ) il fil f b h t d– deep (> 6 in) soil profile for bushes, trees and grasses

• Extensive roofs, designed to drainShallow (< 6 in) soilless media comprised of– Shallow (< 6 in) soilless media comprised of expanded clay, shale or slate

– Plants: Stone crop (e.g. Sedums, Delosperma) p ( g , p )Crassulacean Acid Metabolism (CAM) plants - take in carbon dioxide from atmosphere at night. Photosynthesis in water limited environments withPhotosynthesis in water limited environments with minimal water loss by plant.

– Mat, trays or landscaped (built in place)

Profile of typical green roof system

Rolled mat green roof system

Rolled mat green roof system

Con Edison Training Facility, Queens, NYTray or modular green roof system, walkway to left

Region 8 Green Roof, Denver, COTray or modular green roof system, solar panels to left of picture

Region 8 Green Roof, Denver, COTray or modular green roof system, irrigation required

Region 8 Green Roof, Denver, COArea of green roof: 20,000 ft2

Plant plugs Plugs can be planted in both tray and landscape green roof systems; cuttings are also used in landscaped systems

Emory Knolls Farm, Maryland

Friends Center, Philadelphia, PA Landscaped roof system

Friends Center, Philadelphia, PA Landscaped roof system

Friends Center, Philadelphia, PA

Green Roof with Monitoring EquipmentGreen Roof with Monitoring

Green Roof with Monitoring Equipment November 2003Equipment

June 2005

Relative Percentage Runoff to Retentionto Retention

Precipitation and Runoff from Green and Flat Asphalt Roofs on August 16 2005Asphalt Roofs on August 16, 2005

From “Reducing Urban Heat Islands” (EPA)From Reducing Urban Heat Islands (EPA)

From “Reducing Urban Heat Islands” (EPA)

Benefits of Green RoofsBenefits of Green Roofs• Stormwater control • Temperature reductionTemperature reduction• Protection of roof membrane• Buffering of acid rain• Aesthetics• Ecosystem improvement • Noise reduction• Urban Heat Island

Region 8 Green Roof, Denver, COFlowering plants attracted a bee

EPA Resources

• Reducing Urban Heat Islands: Compendium of Strategies Green RoofsStrategies Green Roofs http://www.epa.gov/hiri/resources/pdf/GreenRoofsCompendium.pdfEvaluation of Green Roof Plants and Materials for• Evaluation of Green Roof Plants and Materials for Semi-Arid Climateshttp://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P100ECC8 t tC8.txt

• Green Roofs for Stormwater Runoff Control http://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P10037p p p g y g y04.txt