Provisional Data

We monitor stream flow, meteorological conditions, water quality and operational conditions at our dams. The information is collected and transmitted from each station to our Operations Centre in Cambridge, Ontario. Once an hour the data are summarized and posted to this website.

Data posted to this website are provisional data that have not been reviewed or edited and are subject to change. These data are not citable until reviewed and approved by the GRCA or our partner agencies.

Factors influencing accuracy

A number of factors will influence the accuracy of real-time water level and flow data including:

• Backwater from ice, weeds or debris,
• Malfunctioning equipment and/or routine maintenance of equipment may cause data spikes, and
• Sediment accumulation may lead to plugged intake.

A number of factors will influence the accuracy of real-time rain fall data including:

• Funnels and instruments may become fouled with debris or insects,
• The tipping bucket mechanism may malfunction, and
• The tipping bucket rain gauge may not properly record precipitation during freezing weather conditions.

A number of factors will influence the accuracy of real-time water quality data including:

• Water quality probes may become fouled with sediment or debris, and
• Malfunctioning equipment and/or routine maintenance of equipment may cause data spikes.

Caution

River levels and flows can change rapidly in response to water entering the river as a result of rainfall or snowmelt, or changes in discharge from the major reservoirs operated by the GRCA.

Users of the GRCA's real-time data are cautioned to consider the provisional nature of the information before using it for decisions that concern personal or public safety or the conduct of business.