Portland State University. Department of Environmental Science and Management
Term of Graduation
Date of Publication
Master of Science (M.S.) in Environmental Science and Management
Environmental Science and Management
Roof runoff -- Composition -- Seasonal variations -- Oregon -- Portland -- Case studies, Green roofs (Gardening), Runoff -- Environmental aspects, Urban runoff -- Management
1 online resource (vi, 53 pages)
Green stormwater infrastructure (GSI), specifically ecoroofs, is increasingly seen as an effective stormwater management tool in urban planning strategies. However, the literature suggests that ecoroofs can be sources of certain metals and nutrients. The goal of our study was to address two research questions: 1) How does ecoroof runoff compare to conventional roof runoff chemically: do ecoroofs retain certain chemicals and leach others? and 2) what are the roof characteristics and environmental variables that affect runoff quality? For 10 months, runoff events from an ecoroof were compared to those of a conventional roof; water samples were collected with autosamplers, and flow was measured with a flow meter. Samples were analyzed for metals by mass spectrometry, and nutrients were analyzed by colorimetry. The ecoroof retained about 38% of the 577 mm of rainfall measured during the sampling period, and retention was closely associated with temperature and storm intensity. The ecoroof was a net source of Al, Fe, and PO4-3 while retaining chemicals that were a source from the conventional roof such as Zn and Cd. Ecoroof orthophosphate unit area loads were controlled by precipitation and temperature. More research needs to be done to improve ecoroof technologies including water treatment residuals, biochar, and mycorrhizae inoculation, which may help prevent the release of pollutants from ecoroof media.
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Bans, Alex Vijay, "A Seasonal Study of Ecoroof Metal and Nutrient Dynamics and Associated Drivers in an Ecoroof on a Commercial Building in North Portland Oregon" (2020). Dissertations and Theses. Paper 5577.
Available for download on Saturday, September 11, 2021