St. Lawrence Ship Channel

Forecasts as of : September 29, 2022

Downward trend of water levels for the following weeks. A decrease of water levels is to be expected due to a 72-hour flow cut at upstream control structures from the 7 to the 10 of October in order to assist with lake Saint-Lawrence boat haul-out.

Forecasted water levels [m above CD]

Stations	3 days (30/09 - 02/10)	4 to 6 days (03/10 - 05/10)	7 to 10 days (06/10 - 09/10)	11 to 14 days (10/10 - 13/10)	Week 3 (14/10 - 20/10)	Week 4 (21/10 - 27/10)
Montreal #15520	▼ 0.65 ■ 0.56 ▲ 0.48	0.57 0.37 0.27	0.55 0.08 -0.04	0.56 0.06 -0.04	0.56 -0.03 -0.14	0.65 -0.01 -0.11
Sorel #15930	▼ 0.81 ■ 0.68 ▲ 0.62	0.70 0.46 0.37	0.68 0.41 0.31	0.84 0.40 0.32	0.83 0.12 0.07	0.97 0.15 0.09
Lake Saint Pierre #15975	▼ 0.83 ■ 0.67 ▲ 0.61	0.72 0.43 0.35	0.75 0.38 0.29	0.89 0.43 0.36	0.87 0.08 0.05	1.07 0.11 0.08
Trois-Rivieres #03360	▼ 0.86 ■ 0.67 ▲ 0.60	0.71 0.44 0.36	0.80 0.40 0.31	0.95 0.48 0.41	0.90 0.07 0.04	1.17 0.10 0.07

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	7600	7130
Current week	7460	7070

Ottawa River at Carillon Dam Outflows [m³/s]

	Current year	Historical meanb (1900-2020)
Last week	1220	1090
Current week	1760	1167

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