Lake Level Guides
Plain-language explanations of how lake and reservoir levels are measured and how to read them.
These guides explain what the numbers on this site mean, where they come from and what they can — and cannot — tell you about conditions on the water.
How Lake Levels Are MeasuredWhat a lake-level gauge records, what "feet above mean sea level" means, and why readings are provisional.
Lake Elevation vs. River StageWhy a river gauge height cannot be compared with a lake surface elevation.
Understanding Reservoir Storage and “Percent Full”How storage in acre-feet relates to elevation, and why percent full is defined differently by each operator.
Last updated November 3, 2026