Research Highlights

Green Roof Research Project Studies Stormwater Absorbency

Fencing Academy of Philadelphia vegetated roof cover. Courtesy of EPA-841-B-00-005D Podcasts Subscribe to podcasts to learn more about how NRMRL research helps to support the protection of human health and the environment.

One of the most interesting stormwater control systems under evaluation by EPA is the “green roofs” program. Green roofs are vegetative covers applied to building roofs to slow, or totally absorb, rainfall runoff during storms. While the concept of over-planted roofs is very ancient, the goals of modern green roof technology are to replace the absorptive capacity of the land on which the building was erected. Research into this approach has been growing steadily since the 1980s, especially in Europe. In the United States, EPA is cooperating in several projects testing green roof technologies; in one of these, created in partnership with Penn State University, risk management researchers are evaluating performance data that could be used to enhance municipal stormwater management planning. The cooperative agreement is being managed by National Risk Management Research Laboratory Urban Watershed Management Branch in Edison, NJ, to demonstrate and promote green roof research, education, and technology transfer in the Northeastern U.S. Initial results have been presented at several conferences. A final EPA report on the research results is anticipated in late 2006.

Components of green roof cover. Courtesy of EPA-841-B-00-005D

Germany, a leader in this field, now has an estimated 800 green roof projects in place. In European countries, many communities have mandated the implementation of green roofs on new buildings. With municipalities in the U.S. looking for flexible ways to control stormwater, including the use of stormwater credits or watershed-based trading, the development of new stormwater controls such as urban green roofs is a vital initiative for EPA.

The EPA-Penn State project investigates the effectiveness of green roofs in limiting stormwater volume discharge and reducing pollutant runoff content. The main research facility consists of six small buildings. Three of these have traditional asphalt shingle roofs and three have green roofs. All building gutters are connected to runoff barrels fitted with pressure transducers to measure runoff. The field tests include real-time continuous runoff, storage, and runoff quantity and quality monitoring to compare green roofs to non-green roofs in the field.

In addition to stormwater runoff, energy data from the test buildings in the field is being recorded. Buildings are insulated, equipped with heaters, and air conditioning, and are instrumented to collect data on heat flux, energy use, and roof-top surface temperature.

Preliminary results from spring 2005 indicate that green roofs effectively buffer acid rain. During the summer of 2005, runoff from many rainfall events of less than 1-inch was entirely contained by the green roofs. Research on design and performance will help municipalities and private entities make decisions associated with green roof technology and assist in matching this technology with other technologies as part of an overall stormwater management plan.

More information on the can be found at:

For further information, contact Jane Ice, NRMRL Office of Public Affairs, 513-569-7311, or email to ice.jane@epa.gov.

New Risk Management Research Publications

Journal Articles

Ju, Yuhong and Rajender S. Varma. "Aqueous N-Heterocyclization of Primary Amines and Hydrazines with Dihalides: Microwave-Assisted Syntheses of N-Azacycloalkanes, Isoindole, Pyrazole, Pyrazolidine, and Phthalazine Derivatives." J. Org. Chemistry, 2006, 71, 135-141.

Juachuck, R. J. J., D. K. Selvaraj and R. S. Varma. "Process Intensification: Oxidation of Benzyl Alcohol Using a Continuous Isothermal Reactor Under Microwave Irradiation." Green Chem., 2006, 8, 29-33.

Kim, Yong Jin and Rajender S. Varma. "Microwave-Assisted Preparation of Imidazolium-Based Tetrachloroindate(III) and their Application in the Tetrahydropyranylation of Alcohols." Tetrahedron Lett. 2005, 46, 1467-1469.

Kim,Yong Jin and Rajender S. Varma. "Microwave-Assisted Preparation of 1-Butyl-3-Methylimidazolium Tetrachlorogallate and its Catalytic Use in Acetal Formation Under Mild Conditions." Tetrahedron Lett. 2005, 46, 7447-7449.

Kim, Yong Jin and Rajender S. Varma. "Tetrahalideindate(III)-Based Ionic Liquids in the Coupling Reaction of Carbon Dioxide and Epoxides to Generate Cyclic Carbonates: H-Bonding and Mechanistic Studies." J. Org. Chemistry, 2005, 70, 7882-7891.

Shekar, S. Chandra, K.S. Rama Rao and E. Sahle Demessie "Characterization of Palladium Supported on y-Al2O3 Catalysts in Hydrodechlorination of CCl2F2" Applied Catalysis A: General, Web published.

Su, Chunming and Richard T. Wilkin. "Arsenate and Arsenite Sorption on, and Arsenate Oxidation by Iron (II, III) Hydroxycarbonate Green Rust." 2005. American Chemical Society Symposium Series 915: 25-40.

Green, R., G. Hater, C. Goldsmith, F. Kremer, and T. Tolaymat. “Commercial-Scale Aerobic-Anaerobic Bioreactor Landfill Operations.” Proceedings of the 10th Sardinia International Solid Waste Symposium, Sardinia, Italy, September/October, 2005.

Groffman, P.M., A.M. Dorsey, and P.M. Mayer. 2005 “N Processing Within Geomorphic Structures in Urban Streams.” Journal of the North American Benthological Society 24:613-625.

Haines, John R. “Laboratory Evaluation of Ten Oil Spill Bioremediation Products in Salt and Freshwater Systems.” Journal of Industrial Microbiology and Biotechnology, 32, 171-185.

Ju, Yuhong, and Rajender S. Varma, “An Efficient and Simple Aqueous N-Heterocyclization of Aniline Derivatives: Microwave-assisted Synthesis of N-aryl Azacycloalkanes.” Org. Lett. 2005, 7, 2409-2411.

Ju, Yuhong, and Rajender S. Varma. “Microwave-assisted Cyclocondensation of Hydrazine Derivatives with Alkyl dihalides or ditosylates in Aqueous Media: Syntheses of Pyrazole, Pyrazolidine and Phthalazine Derivatives.” Tetrahedron Lett. 2005, 46, 6011-6014.

Kim, Y., and R.S. Varma. 2005. “Imidazolium-Based Tetrahalide Indate III: Recyclable Catalysts for Efficient Coupling Reaction of Carbon Dioxide.” Journal of Organic Chemistry, 70 (20),7882-7891.

Matocha, C.J., K.G. Scheckel, and D.L. Sparks. “Chemical Processes in Soils.” Tabatabai, M.A. (ed), Madison, WI. Soils Science Society of America Special Publication Book Series 8: 309-342.

Morrison, Matthew A. and Gaboury Benoit (2005). “Temporal Variability in Physical Speciation of Metals During a Winter Rain-On-Snow Event.” Journal of Environmental Quality, 34, 1610-1619.

Roy, Allison H., Christina L. Faust, Mary C. Freeman, and Judith L. Meyer. 2005. “Reach-Scale Effects of Riparian Forest Cover on Urban Stream Ecosystems.” Journal of Fisheries and Aquatic Sciences, 62, 2312-2329.

Sanders, J.A., M.K. Lee, A. Uddin, S. Mohammad, Richard T. Wilkin, Mostafa Fayek, and Nic E. Korte. “Natural Arsenic Contamination of Holocene Alluvial Aquifers by Linked Tectonic, Weathering, and Microbial Processes.” 2005. Geochemistry, Geophysics, Geosystems (G3), 6, 4:1-7.

Scheckel, Kirk G., James A. Ryan, Derrick Allen, and Ninnia V. Lescano. 2005. “Determining Speciation of Pb in Phosphate-Amended Soils: Method Limitations.” Science of the Total Environment. 261-272.

Su, Chunming and Ralph D. Ludwig. “Treatment of Hexavalent Chromium in a Chromite Ore Processing Waste Using a Mixed Reductant Solution of Ferrous Sulfate and Sodium Dithionite.”
2005. Environmental Science & Technology, 39,16 :6208-6216.

Varma, Rajender S., Yuhong Ju, “Green Separation Processes: Fundamentals and Applications.” Carlos A. M. Afonso and Jo?o P. S. G. Crespo (Eds), 2005. Solventless Reactions (SLR), 2005. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Ch. 2.2, 53-88.

Walsh, Christopher J., Allison H. Roy, et al. 2005. “The Urban Stream Syndrome: Current Knowledge and the Search for a Cure.” Journal of the North American Benthological Society, 24,3:706-723.

Wilson, John T., Cherri Adair, Philip M. Kaiser, and Ravi Kolhatkar. 2005. “Anaerobic Biodegradation of MTBE at a Gasoline Spill Site.” Ground Water Monitoring & Remediation, 25, 3:1003-115.

Wilson, John T., Philip M. Kaiser, and Cherri Adair. “Monitored Natural Attenuation of MTBE as a Risk Management Option at Leaking Underground Storage Tank Sites.” 2005. EPA Report EPA/600/R-04/179. National Risk Management Research Laboratory, Cincinnati, Ohio.

Wilson, John T., Randall R. Ross, and Steven Acree. 2005. “Using Direct-Push Tools to Map Hydrostratigraphy and Predict MTBE Plume Diving.” Ground Water Monitoring & Remediation, 25,3:93-102.