Great Lakes Monthly Hydrologic Data

Accurate hydrologic data (over-lake precipitation, runoff, lake evaporation, net basin supplies, connecting channel flows, diversion flows, beginning-of-month lake levels, and changes in storage) are required for simulation, forecasting, and water resource studies on the Laurentian Great Lakes and their basins. These data are derived from meteorological and hydrological data. The 1993 reference is an update of the earlier report describing Great Lakes monthly hydrologic data. It was expanded and revised to include all available data through 1990 and to reflect improved computational techniques. The raw data utilized were collected from several sources, so the periods of record for each lake vary.