The major diversions in the Great Lakes basin that affect water levels are diversions into Lake Superior at Long Lac and Ogoki, the Chicago diversion out of Lake Michigan and a diversion between lakes Erie and Ontario through the Welland Canal.
The International Lake Superior Board of Control is responsible for regulating the outflow of Lake Superior and managing the control works on the St. Marys River.
Basin conditions were generally near average or drier than average in June, around both Lake Superior and Lake Michigan-Huron. As a result, water levels did not rise as much as they typically do in June.
While conditions around Lake Superior were drier than average in May, conditions were again wetter than average on Lake Michigan-Huron, driven by a couple of significant rainfall events in the middle and at the end of the month.
Conditions across the Great Lakes were generally drier this past month and the water levels of both Lake Superior and Lake Michigan-Huron rose less than they typically do in April. Nonetheless, an exceptional volume of water remains in the system.
Wet conditions returned to the Great Lakes this past month and the water levels of both Lake Superior and Lake Michigan-Huron rose slightly more than they typically do in March.
Conditions across the Great Lakes were drier this past month and the water levels of both Lake Superior and Lake Michigan-Huron declined more than they typically do in February.
Lake Superior and Lake Michigan-Huron water levels are above record-highs for this time of year as wet conditions persisted across the upper Great Lakes basin in January.
Lake Superior and Lake Michigan-Huron remain near record-highs for this time of year, but are expected to continue their seasonal declines in December.
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