Bioretention systems are commonly used to treat and detain stormwater runoff and help mitigate for many negative effects of urbanization. Despite the widespread use of bioretention systems, few field-based studies have assessed how these facilities affect water quality many years after installation. The goal of this project is to assess the pollution reduction effectiveness of lined bioretention facilities that have been in use and functioning for 4–8 years. To meet this objective, this project measured water quality characteristics of stormwater flowing into and out of seven facilities installed throughout Portland, Oregon during real storm events. Stormwater grab samples were taken over a 2-year period during the fall, winter, and spring. Results showed decreased concentrations of total suspended solids (TSS; 94%), ammonia (85%), total copper (59%), total zinc (80%), and dissolved zinc (41%). Results for dissolved copper indicated an overall increase in outflow concentrations of 23%, however variability between facilities was high. These results support other similar findings showing that TSS is effectively reduced by bioretention facilities, even after 4–8 years of use. However, based on this study, effective TSS removal by bioretention facilities does not necessarily equate to equally effective treatment of other pollutants, especially orthophosphate and nitrate, which increased in outflow from the bioretention facilities by 141% and 2070%, respectively. Results of this study indicate that additional research is necessary to determine the significance of the observed increase in nutrients, understand the underlying mechanisms, and test possible design modifications to improve nitrate and orthophosphate removal.
|Commitee:||Foster, Eugene, Poor, Cara|
|School:||Portland State University|
|School Location:||United States -- Oregon|
|Source:||MAI 81/4(E), Masters Abstracts International|
|Subjects:||Environmental science, Water Resources Management, Environmental management|
|Keywords:||Bioretention, BMP, Nutrients, Stormwater, Urbanization, Water quality|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be