Date of Award

Summer 8-18-2019

Document Type

Project

Degree Name

Master of Science (M.S.) in Civil & Environmental Engineering

Department

Civil and Environmental Engineering

First Advisor

William Fish

Subject Categories

Civil and Environmental Engineering

Abstract

Portland, Oregon is internationally recognized for its implementation of sustainable stormwater management technologies. Ecoroof is one of the sustainable solutions to reduce stormwater runoff which also provides multiple environmental benefits. However, very little is known about the impact of ecoroofs on water quality of roof runoff. Stormwater runoff carries a significant amount of pollutants, which, if it directly enters a stream or river, degrades water quality and severely harms aquatic life.

This study evaluates the trends in the long-term water quality data from ecoroofs and conventional roofs in the Portland area. Mann Kendall trend test was used to detect the trends in concentrations of parameters. Concentration levels of metals (copper, lead, zinc) and nutrients (nitrogen and phosphorous) in runoff from ecoroofs were compared with the runoff from conventional roofs using Mann Whitney U test. Results indicated elevated levels of copper and phosphorous in ecoroof runoff. Concentrations of lead and zinc were found to be lower in ecoroof runoff than conventional roof runoff. Monitoring of ecoroof for a longer period is recommended for future studies to quantify the effect of roof age, thickness, and composition of soil media, and plant types on runoff.

Available for download on Sunday, August 18, 2019

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