Monthly Water Level Bulletin  

A network of gauging stations on both sides of the border on each lake is used to determine the average water level for the month. The following stations are used:

Lake Superior at:  Thunder Bay, Michipicoten, Duluth, Marquette and Point Iroquois        

Lakes Michigan/Huron at:  Thessalon, Tobermory, Milwaukee, Ludington, Mackinaw City and Harbor Beach  

Lake St. Clair at:  Belle River and St. Clair Shores

Lake Erie at:  Port Stanley, Port Colborne, Toledo and Cleveland   

Lake Ontario at:  Port Weller, Toronto, Cobourg, Kingston, Rochester and Oswego          

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Great Lakes and Montreal Harbour

Monthly Bulletin prepared by the
Canadian Hydrographic Service
Fisheries and Oceans Canada  

Grands Lacs et port de Montréal

Bulletin mensuel préparé par le
Service hydrographique du Canada
Ministère des Pêches et des Océans

April 2013 Avril

Water Level Advisory  

Water levels on Lake St. Clair, Lake Erie, Lake Ontario, and at Montreal Harbour are below their all-time average for this time of year and are above the level of Chart Datum. Lake Superior and Lake Michigan-Huron are below their all-time average for this time of year and are below the level of Chart Datum. Mariners should exercise extreme caution throughout the entire system, especially during periods of strong winds when water levels can rise or fall significantly in a short period of time.

 

Monthly Mean Water Levels in metres referred to IGLD 1985			Niveau d'eau moyen mensuels en metres par rapport au SRIGL 1985
April  2013  Avril	Superior Supérieur	Huron	St. Clair Sainte-Claire	Erie Érié	Ontario	Montréal
Mean for Month (preliminary data) Moyenne mensuelle (données préliminaires)	182.92	175.75	174.76	174.02	74.72	6.80
Mean for month last year Moyenne mensuelle, l'année dernière	183.00	176.03	174.99	174.31	74.92	6.65
Mean for month, last 10 years Moyenne mensuelle, 10 dernières années	183.06	176.01	174.94	174.24	74.92	7.10
Statistics for period of record Statistiques pour la periode d'observation	1918-2012	1918-2012	1918-2012	1918-2012	1918-2012	1967-2012
Maximum monthly mean / year Moyenne mensuelle maximale / année	183.68 1986	177.23 1986	175.82 1986	174.98 1985	75.65 1973	8.82 1976
Mean for month / Moyenne mensuelle	183.26	176.38	175.04	174.22	74.88	7.44
Minimum monthly mean / year Moyenne mensuelle minimale / année	182.72 1926	175.61 1964	174.32 1926	173.38 1934	74.03 1935	6.11 2003
Probable mean for next month Moyenne probable du mois prochain	183.04	175.92	174.84	174.14	74.93	6.80
Chart Datum  /  Zéro des cartes	183.20	176.00	174.40	173.50	74.20	5.55

Information

The monthly mean levels for the previous year and current year shown on the graphs are the average of water levels recorded at a network of gauging stations on each lake.  Historical data from these networks are used to determine the all-time average and the historical extreme monthly levels.

Water levels for the Canadian stations in the networks are collected by the Canadian Hydrographic Service.  Six month forecasts of the probable range of future levels are prepared under the auspices of the International Coordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data by Environment Canada and the Detroit District, Corps of Engineers.

This bulletin is prepared each month as a public service and is available on the World Wide Web at:

http://www.waterlevels.gc.ca/C&A/bulletin_e.html

Additional information on water levels in the Great Lakes System may be obtained by telephoning the Canadian Hydrographic Service at (877) CHS-LINK (877-247-5465), by fax at (905) 336-8916, or by email at  CATCWL@dfo-mpo.gc.ca