St. Lawrence Ship Channel

Forecasts as of : August 31, 2023

Water levels are expected to decrease over the next few days following the recent rise in levels due to recent rainfall events. Water levels should remain relatively stable in the longer term.

Forecasted water levels [m above CD]

Stations	3 days (01/09 - 03/09)	4 to 6 days (04/09 - 06/09)	7 to 10 days (07/09 - 10/09)	11 to 14 days (11/09 - 14/09)	Week 3 (15/09 - 21/09)	Week 4 (22/09 - 28/09)
Montreal #15520	▼ 0.98 ■ 0.84 ▲ 0.78	0.92 0.73 0.65	0.83 0.59 0.49	0.83 0.57 0.47	1.00 0.59 0.49	1.05 0.55 0.43
Sorel #15930	▼ 1.10 ■ 0.99 ▲ 0.95	1.04 0.79 0.73	0.83 0.55 0.48	0.84 0.53 0.46	1.04 0.59 0.52	1.09 0.52 0.45
Lake Saint Pierre #15975	▼ 1.15 ■ 1.05 ▲ 1.01	1.08 0.80 0.75	0.83 0.51 0.43	0.81 0.48 0.41	1.04 0.57 0.50	1.09 0.47 0.41
Trois-Rivieres #03360	▼ 1.25 ■ 1.15 ▲ 1.10	1.16 0.86 0.80	0.90 0.54 0.49	0.91 0.51 0.45	1.16 0.63 0.58	1.19 0.49 0.44

Notes :

1. The water levels associated with the probabilities of exceedance shown in the table are calculated from historical errors between forecasted and observed water levels. As a guide, there is a probability of about 15% that future water levels will be below the forecasted water levels for which there is a 85% probability of exceedance.
2. The data in this bulletin, released Monday and Thursday of each week, is produced by the Hydraulic Engineering Sector of the Canadian Coast Guard, Headquarters, to help Commercial Mariners plan their activities for the next 4 weeks.
3. The Canadian Coast Guard makes no warranty on the information contained in this bulletin and assumes no responsibility for any loss or damage incurred as a result of the use of this information.
4. Hydro-meteorological factors can influence future water levels. The master of the vessel or the officer on duty is responsible for the safety of the vessel at all times.
5. It is the responsibility of the maritime industry to maintain a sufficient safety margin in relation to these forecasts.
6. The presence of ice could induce large variations in water levels. The water levels forecast in this bulletin do not take into account the potential variations resulting from the presence and possible management of this ice.

a. Water level modeled from available hydro-meteorological data (observed and forecast).

Lake Ontario Outflows [m³/s]

	Current year	Historical meanb (1900-2020)
Last week	8380	7340
Current week	8260	7270

Ottawa River at Carillon Dam Outflows [m³/s]

	Current year	Historical meanb (1900-2020)
Last week	1900	1132
Current week	1590	1101

b. As published by International Lake Ontario - St. Lawrence River Board