Contact(s)
- Learn how to read these charts on our River and stream flows page.
- This river data can be downloaded from our Data Downloads page.
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.
Critical flows
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 R.) | 0.3 | Normal summer low flow | |
| West Montrose | West Montrose | 5 | Normal summer low flow |
| 125 | Campground floods | ||
| Up to 180 | Warning level 1 | ||
| 180 - 280 | Warning level 2; village floods | ||
| 280 - 400 | Warning level 3 | ||
| 670 | 1974 flood | ||
| 400 - 700 | Warning level 4 | ||
| 700 - 1400 | Warning level 5 |
Location of flow gauges in the Upper Grand River
