Great Lakes Water Levels Updates

Written by Kalie Walter
September 21, 2021

Expected water levels on the Great Lakes.

See enclosure for the expected water levels on the Great Lakes. Connecting Channels and the St. Lawrence River, given in inches above (+) or below (-) Low Water Datum (LWD). LWD is a plane of reference used on a navigation chart. It is also known as chart datum.See EnclosureAvailable water depth is determined for a location by adding (if +) or subtracting (if -) the amount from the above to the water depth shown on National Oceanic and Atmospheric Administration (NOAA) navigational charts. Caution: Depths so determined are representative of a still water surface elevation, disturbed by neither wind nor other causes. Depth, however, may be reduced or increased as much as several feet for short periods of time due to these disturbances, or when sections of channels develop shoals. Vessel masters should refer to the Local Notice to Mariners for extent of shoaling and scattered bedrock projections in all channels. For further information direct inquiries to: Department of the Army, Detroit District Corps of Engineers P. O. Box 1027, Detroit, MI 48231, (313) 226-6443. Additional information can be found on the U.S. ArmyCorps of Engineers Information Center website at

View the levels here.

Chuck Baier

[email protected]