Publication Date

2019

Document Type

Dissertation/Thesis

First Advisor

Lenczewski, Melissa E.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Earth, Atmosphere and Environment

Abstract

Boeng Cheung Ek wetland is a large, peri-urban, free water surface, natural wastewater treatment wetland that services approximately 90% of combined storm water and untreated sewage from the city of Phnom Penh, Cambodia, population over 1.5 million. Due to monsoon rainfall and connectivity to the Mekong River, the wetted area cycles between 13 km2 and 20 km2 annually. The objective of this study is to characterize the spatiotemporal variability of contaminants in wetland surface water and groundwater. Dissolved ions including ammonium, nitrate-N (as NO3), phosphate, and chloride, along with E. coli, trace metals, δH, δ18O, and physicochemical parameters were determined for wet and dry seasons. Three wells with chloride ten times above background levels are identified. The influence of the fresh water pulse from the Mekong River is shown using data loggers and rainfall. Inputs from agricultural activities and domestic sewage are observed between the two outlet streams. Treatment performance for readily biodegradable organic matter is high; however, water quality up to four kilometers away from inlets is extremely poor. Boeng Cheung Ek is in the process of being filled in as an extension of the city even as an appropriate replacement system for sewage treatment remains unresolved. Additionally, a pilot-study is presented using an open-source and low-cost small unmanned aerial system with structure-from-motion photogrammetry for producing high resolution digital elevation models (DEM). A 1.2 km2 DEM with an average ground sampling distance of only 6.67 cm was compared to eight RTK-GNSS ground control points yielding a mean vertical error of 4.96 m and standard deviation of 0.67 m. Data from this emerging technique has applications including environmental monitoring, referencing well elevation for groundwater modeling, measuring surface water level, and serving as an input for flood modeling.

Extent

152 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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