2020-Oct-01
Sept 27 Water Levels Report
Water levels continue to be well above average and near or above record high levels.
From a month ago the water levels on Lakes Superior, Michigan-Huron, St Clair, Erie & Ontario are down 1, 4, 4, 4 & 9 inches respectively. Lakes Superior, Michigan-Huron, St. Clair, Erie & Ontario, are lower by 4, 0, 0, 2 & 15 inches, respectively, than they were at this time last year. Lakes Superior, Michigan-Huron, St Clair, Erie & Ontario are 9, 30, 28, 23 & 1 inches, respectively, above their long term September average. All the lakes are at or below their September record high.
In a month’s time, the level of Lake Superior is expected to be 1 inch lower, and Lakes Michigan-Huron, St Clair, Erie & Ontario are expected to be 3 or more inches lower. Outflows from Lake Superior into the St. Mary’s River and Lake Michigan-Huron’s outflow into the St. Clair River are predicted to be above average for this month. Lake St. Clair’s outflow through the Detroit River and Lake Erie’s outflow through the Niagara River are also forecasted to be above average in this month. In addition, Lake Ontario’s outflow through the St. Lawrence River is projected to be above average for this month.
High water levels and potentially record high water levels are expected to persist for at least the next six months, so flood prone areas are expected to remain vulnerable.
With regard to the forecast graph below, and the more recently updated first graph in this report, the USACE is predicting that the most likely outcome is that levels will continue to decline through the remainder of the year.
Please note that the purple and blue lines, and dotted lines, in the USACE forecast graph show what happened with water level changes from month to month in each of the years 1986-87, 1977-78, 1930-31 and 1976-77 – they do not represent actual water levels in those years.