Upper Grand flows | Grand River Conservation Authority

Learn how to read these charts on our River and stream flows page.
Many timeseries can be downloaded from our Data Downloads page.

Critical flows

**Critical flows table:** This chart will help you understand the significance of various flows levels. The chart shows the name of the gauge, the affected communities and various flow levels along with the significance of that flow level. Flows are measured in cubic metres per second, i.e. the amount of water flowing past a spot in one second.
Gauge (Community)	Flow (m³/s)	Significance
Riverview	0.1	Normal summer low flow
Legatt (Grand Valley)	0.5	Normal summer low flow
	60	Water at banks; low-lying areas flooded
	135	Water over CR25
	255	Major flooding
Marsville (Waldemar)	0.8	Normal summer low flow
	65	Water at banks; low-lying areas flooded
	290	Major flooding
Shand discharge (Elora)	160	Elora boardwalk floods
Salem, Irvine River	0.3	Normal summer low flow
West Montrose	5	Normal summer low flow
	125	Campground floods
	Up to 180	Warning Zone 1
	180 - 280	Warning Zone 2; village floods
	280 - 400	Warning Zone 3
	670	1974 flood
	400 - 700	Warning Zone 4
	700 - 1400	Warning Zone 5

Location of flow gauges in the Upper Grand River

Provisional Data

Caution: 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.

The Grand River Conservation Authority assumes no responsibility for the correctness of the information contained in this website nor liability to any user of such information, regardless of the purpose.

Warning! River levels and flows can change rapidly.