Monitoring water quality for recreational use in nearshore waters of Eastern Georgian Bay

Abstract

Georgian Bay is well known for its excellent water quality and recreational beauty; however, some regions are showing signs of degradation and eutrophication, threating the way of life for residents and cottagers. The goal of my thesis is to provide the Township of Georgian Bay (TGB) with updated resources, including information on their water quality and a sampling protocol that local community members can use, so water quality can be effectively managed and protected. First, we investigated the changes in water quality from a historic period (2001 – 2009) to the current period (2020 – 2022). We found that 80% of sites had a decrease in E. coli (EC) between periods, likely associated with increased dilution from an approximately 1 m increase in water levels. Secondly, we examined regional variation within TGB and found that Honey Harbour and Oak Bay had the highest mean EC and total phosphorus (TP) concentrations and therefore are of greatest concern. Next, we wanted to understand what potential factors could be influencing this regional variation and found that mean EC and TP were positively and significantly correlation with road density and the percentage of modified area. Lastly, we designed a novel method for monitoring nutrient status in nearshore waters using periphyton that can be used by local community members. We found that the periplate results are sensitive to areas of high human disturbance and may be used in volunteer monitoring programs. The results of this study can help the TGB and other similar municipalities make informed management decisions and policies to protect the excellent water quality of Georgian Bay.