Graduation Term

Summer 2025

Degree Name

Master of Science (MS)

Department

Department of Geography-Geology: Hydrogeology

Committee Chair

Eric Peterson

Committee Member

Wondessen Seyoum

Committee Member

Jonathan Thayn

Abstract

Urban streams, impacted by urbanization, often exhibit degraded water quality due to elevated nutrient levels, a phenomenon known as urban stream syndrome. This study evaluates the effectiveness of a floating wetland (FW) system in reducing nitrate as nitrogen (NO₃-N) and phosphate (PO₄³⁻) concentrations in a side canal of the Chicago River’s North Branch, adjacent to Goose Island, Chicago, IL, from 2018 to 2023. Using a five-year dataset, including new sampling from May to December 2023, the research addresses two questions: (1) Do FWs lower NO₃-N and PO₄³⁻ concentrations in urban streams? and (2) Do FWs exhibit seasonal differences in nutrient reduction performance between growing (April–September) and dormant (October–March) seasons? Water samples were collected upstream and downstream of a 90 m² FW at surface and 0.3 m depths, analyzed via ion chromatography, and subjected to paired t-tests and two-way ANOVA. Results indicate significant reductions in NO₃-N (mean difference: 1.31 mg/L surface, 1.02 mg/L 0.3 m) and PO₄³⁻ (mean difference: 0.64 mg/L surface, 0.57 mg/L 0.3 m) downstream, with p-values < 0.001 for most tests. No significant seasonal differences in reduction effectiveness were found (Location-Season interaction p > 0.05), suggesting consistent year-round performance. The FW’s nutrient removal, driven by plant uptake, microbial denitrification, and sedimentation, offers a sustainable solution for mitigating nutrient pollution in urban streams, with implications for broader ecological restoration efforts.

Access Type

Thesis-Open Access

DOI

https://doi.org/10.30707/ETD.1763755358.764702

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