Date of Award

7-7-2020

Publication Type

Master Thesis

Degree Name

M.A.Sc.

Department

Civil and Environmental Engineering

Keywords

E. coli Modelling, Livestock, Model Calibration and Validation, Sensitivity Analysis, SWAT Model, Water Budget

Supervisor

Tirupati Bolisetti

Supervisor

Rajesh Seth

Rights

info:eu-repo/semantics/embargoedAccess

Abstract

A record number of beach closures and warnings during the summer season have drawn region-wide attention because of the importance of beach water quality to the public. Identification and quantification of the pollutant loadings from the local subwatersheds is imperative to improve beach water quality. To understand the contribution of local subwatersheds into the south shore region of Lake St. Clair, a semi-distributed watershed simulation model, the Soil and Water Assessment Tool (SWAT), was employed. The overall goal was to identify impaired subwatersheds for pathogens by determining the major water budget components of subwatersheds, and the model parameters that control the fate and transport of Escherichia coli (E. coli). Agricultural management, crop rotation and tile drainage parameters were incorporated to obtain accurate water balance. Sensitivity analysis was performed for both flow and E. coli. This research was the first attempt to perform a water budget analysis and to simulate E. coli with SWAT for the Lake St. Clair watershed located within the Essex region. For the daily hydrologic calibration process, the model performance provided a “good” prediction of watershed (Nash-Sutcliffe Efficiency [E]>0.6). Monthly calibration and validation of the pathogen fate and transport model was conducted for E. coli at five sampling locations, and the calibration results indicate a “good” prediction for E. coli (E = 0.74) while at the downstream calibration locations the results compared well with many similar E. coli modelling studies (0.13 < E < 0.46). The livestock manure from feedlots was identified as the major non-point source pollutant to local subwatersheds of the Lake St. Clair region, contributing the most (>55%) to the total E. coli concentrations. This research has mapped critical source areas from a microbial loading point of view where best management practices can be implemented.

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