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Great Lakes and Harbors

Great Lakes Water Management

The U.S. Army Corps of Engineers Detroit District's hydraulics and hydrology branch manages content pertaining to Great Lakes water levels, forecasts, outflows, and basin conditions.


Note: Great Lakes water levels are referenced to the International Great Lakes Datum of 1985 (IGLD 85).

Charts & Graphs

Monthly mean lakewide water levels (from 1918 to present) including long-term averages, maximums, minimums, and monthly means. It also includes daily Great Lakes water levels and real-time gage data for connecting channels water levels. 

Weekly water-level forecasts for the Great Lakes and connecting channels, and our six-month forecast bulletin and our future-scenarios product.

Information on Great Lakes regulation, including Lake Superior outflow and compensating works gate settings, in addition to information on connecting channel discharge measurements, and information on conveyance-change monitoring.

Data for recent net basin-supply conditions including precipitation, evaporation, runoff, snow water equivalent, ice cover, and surface water temperature, as well as long term-basin trends for lakes Superior, Michigan-Huron, Erie, and Ontario. 


Explore Great Lakes Water Management

All Great Lakes Water Management data contained herein is preliminary in nature and therefore subject to change. The data is for general information purposes ONLY and SHALL NOT be used in technical applications such as, but not limited to, studies or designs. All critical data should be obtained from and verified by the United States Army Corps of Engineers Detroit District, Engineering and Construction Division, Hydraulics and Hydrology Branch, 477 Michigan Avenue, Detroit, MI 48226. The United States of America assumes no liability for the completeness or accuracy of the data contained herein and any use of such data inconsistent with this disclaimer shall be solely at the risk of the user.

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