Use this page to produce a tabular or graphical report of historic average monthly flows for Great Lakes connecting channels and major diversions over a specified time period.

Instructions are available at the bottom of this page.

Please read the Disclaimer before proceeding.

You can choose to include the Record High, Record Low, and Long Term Average for the period of record in your report. The following report output options are available:

• Table: A table can be generated containing flows for one or more months over a specified set of years. Select the –All Years– and the –All Months– entries to specify all years or all months for a selected group of years. You must specify at least one year and month to display.
• Yearly Comparison Graph By Month: You can generate a graph depicting historic flows for a specified set of years for specified months. You are limited to selecting a maximum of 7 datasets to graph, inclusive of the specified year(s), record high, record low, and long-term average options, in order to keep the graph legible and to reduce the chance of a timeout during graph generation. You must specify at least two years and 2 months to display.
• Graph For Consecutive Years: Select this option to generate a graph displaying historic flows for all months of a specified range of consecutive years. You may specify –All Years– or a subset of years for a river or diversion along with any combination of record high, record low, and long-term average options for output. At least two years must be selected for this option. Use the Yearly Comparison Graph By Month option if you only want to produce a graph for a diversion over a one-year period.

If generation of your requested report appears to stall or no report data is included on the resulting report output page, narrow your specified time period and retry the operation.