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Boreal Community Media

Lake Superior levels rise in May

Jun 04, 2020 05:32AM ● By Editor
Point des Chenes beach on Lake Superior is pictured in this file photo. Photo: Michael Purvis/SooToday

From The International Lake Superior Board of Control - June 3, 2020

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. This has resulted in additional record-high water levels, which pose a continued risk of shoreline damages in the coming months.

Lake Superior rose 1.9 inches (5 cm) over the course of the month, while on average the water level rises 3.9 inches (10 cm) in May. At the beginning of June, Lake Superior is 5.9 inches (15 cm) below the record-high beginning-of-month level set last year in 2019. The level is currently 10.2 inches (26 cm) above average (1918 – 2019).

Water levels are expected to remain high over at least the next several months and further record highs are possible if wet conditions persist. As a result, there will continue to be a significantly increased risk of shoreline erosion, lakeshore flooding and coastal damages over the next several months. The International Lake Superior Board of Control (Board) advises all those that may be affected to prepare for potentially severe coastal impacts, especially during periods of strong winds and high waves.

The Board expects the total outflow to remain at 2,290 m3 /s in June, as prescribed by Lake Superior Regulation Plan 2012. The outflow in June is just 100 m3 /s above average and the lowest June outflow since 2013, which is in part a reflection of Plan 2012 adjusting to the relatively wetter conditions and higher levels experienced on Lake Michigan-Huron in comparison to Lake Superior in recent months.

The gate setting of the control structure will be maintained at the current setting equivalent to one-half gate fully open (Gates #7 through #10 each open 20 cm). There will be no change to the setting of Gate #1, which supplies a flow of about 15 m3 /s to the channel north of the Fishery Remedial Dike.

Shoreline businesses and property owners are reminded that the Great Lakes – St. Lawrence River Adaptive Management (GLAM) Committee continues to host an online questionnaire to allow for direct reporting on impacts related to recent high water conditions. The 2020 version of the questionnaire is now available here.

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