Since 2002, Toronto and Region Conservation’s (TRCA) Regional Watershed Monitoring Program has been collecting monthly water quality samples in many tributaries throughout its jurisdiction, including a number of sites in partnership with Ontario’s Provincial Water Quality Monitoring Network.
The water samples are analyzed for several contaminants, including metals, chloride and E. coli, which can be harmful to aquatic life and human health. For example, phosphorus and nitrogen are measured because high concentrations can lead to poor water quality conditions such as algal blooms, water void of oxygen, or toxic conditions for fish and other aquatic species.
A summary of the water quality data and methods used is reported annually, and trends are analyzed over five-year time periods.
The most recent reports published are the 2016 Surface Water Quality Summary, as well as two reports that summarize the 2011-2015 trends observed over time and spatially across the regional watersheds. The five-year reports also evaluate the 2011-2015 time period against the long-term data collected over the past 50 years.
While many of these substances are naturally occurring in the environment, high concentrations can be toxic to aquatic life and humans.
Metals generally enter streams through run-off from industry, landfills and sewage treatment effluent, while chloride generally comes from road salts applied during the winter season. E. coli, phosphorus and nitrogen can come from many sources including fertilizers and sewage effluent.
Higher total suspended solids values can be caused by construction sites, untreated stormwater and extreme rain events scouring stream banks.
Learn more about what needs to be done and what we are currently doing in Toronto and region concerning water quality:
Despite the efforts by many organizations to mitigate these impacts and improve general stream water quality (such as improvements in sewage treatment capabilities and stormwater management), it is clear from the long-term monitoring data that more efforts are needed to meet the stream water quality objectives set by the province.
WATER QUALITY REPORTSSave All
2016 Surface Water Quality Summary: Regional Watershed Monitoring Program (August 2017)
This report presents results for selected parameters from the 2016 surface water quality sampling. It provides a general overview and description of the range of water quality conditions across the TRCA jurisdiction during 2016.
Regional Watershed Monitoring Program: Surface Water Quality Temporal Trends Update 2011-2015
Stream water quality was measured across the Toronto Region between 2011 and 2015 as part of the Toronto and Region Conservation Authority’s Regional Watershed Monitoring Program. These data were recently compiled into a report adding this time period to the findings over the past 50 years of monitoring data.
Regional Watershed Monitoring Program: Surface Water Quality Summary - Spatial Trends 2011-2015
Stream water quality was measured across the Toronto region between 2011 and 2015 as part of the Toronto and Region Conservation Authority’s Regional Watershed Monitoring Program. These data were recently compiled into a report summarizing this time period.
Through scientific data collection, TRCA’s Environmental Monitoring and Data Management team tell the stories about the changes affecting the natural areas and watercourses within our regions. For more information, please visit our Web page, follow us on Twitter, subscribe to our Monitoring Matters e-newsletter, or visit our YouTube playlist.