Coordinated Great Lakes lake-wide average monthly mean water levels

This dataset consists of lake-wide average monthly mean water levels for Lakes Superior, Michigan-Huron, Saint Clair, Erie, and Ontario. The data are presented in meters with reference to the International Great Lakes Datum (IGLD) 1985. The dataset is computed and stewarded by Environment and Climate Change Canada (ECCC) and the United States Army Corps of Engineers (USACE), under the auspices of the Coordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data (Coordinating Committee)1. Each agency independently computes and manages their own version of the dataset. The data are binationally coordinated annually, where ECCC and USACE compare their versions to verify that they are consistent. 

The lake-wide average monthly mean water levels are computed from daily hydrometric observations collected from a network of gauging stations located around each lake and on both sides of the Canada-United States border. The gauges are owned and maintained by the Canadian Hydrographic Service (CHS)2 and the National Oceanic and Atmospheric Administration (NOAA)3.  

Detailed metadata and data files for each lake are provided within this dataset. The data files are in comma separated value format (CSV). The CSV data files contain both the lake-wide average monthly mean water level and concise metadata described in accordance with the Climate and Forecasting (CF) conventions. The detailed metadata is in PDF format and provides extended descriptions of data sources, computation methods, dataset history, and related information for each great lake.   

1Coordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data https://www.greatlakescc.org/en/home/ 

2DFO 2024. Marine Environmental Data Section Archive, https://meds-sdmm.dfo-mpo.gc.ca, Ecosystem and Oceans Science, Department of Fisheries and Oceans Canada. 

3NOAA 2024. Tides and Currents, https://tidesandcurrents.noaa.gov/, Center for Operational Oceanographic Products and Services, National Oceanic and Atmospheric Administration.