The first of the following two graphics shows average annual lake levels since 1860; the year in which systematic records were first kept. The second graphic shows the vertical range of water levels on Superior.
Sources of Information
For a comparison with present, or recent, lake levels, visit Forecast Lake Levels. At this site, select Weekly Great Lakes water levels forecast or the Monthly Bulletin of lake levels for the Great Lakes.
Water levels in the graphic shown above are given in meters above International Great Lakes Datum, 1985. Credit: Gene Clark
Water levels on the graphic shown above are given in feet above and below Chart Datum, or Low Water Datum, of 601.1 feet, International Great Lakes Datum, 1985. Credit: Gene Clark
