2021 Water Quality Model Calibration | City of Markham, ON, Canada

The City of Markham’s water distribution system is supplied through the Region of York transmission network with water derived from the City of Toronto and the Region of Peel. Accordingly, the City does not engage in treatment or disinfection operations as raw source water from Lake Ontario is treated by the supplying utilities prior to reaching the City’s system. Moreover, it is understood that the City of Toronto and Peel Region (as well as York Region, where necessary) typically use chloramination for secondary disinfection as it is less volatile (more stable) than chlorination alone, therefore maintaining a long-lasting disinfectant residual. This is particularly important in distribution systems, such as the York Region-Markham system, which may be subject to high water age from long residence times and potentially low turnover via processing through numerous storage facilities. To protect consumers from microbiological risk, the City monitors a wide range of water quality param...