LAKE SUPERIOR OUTFLOWS January 2017 #LSN_Shipping
THUNDER BAY, ON --- January 3, 2017 (LSN) The net water supplies to Lake Superior were above average in December. The level of Lake Superior declined 8 cm (3 in), which is the average decline in December. The Lake Superior level at the beginning-of-January is 14 cm (6 in) above average, 8 cm (3 in) below the level recorded a year ago at this time, and 30 cm (12 in) above its chart datum level.
The International Lake Superior Board of Control, under authority granted to it by the International Joint Commission (IJC), has set the Lake Superior outflow to 2,400 cubic meters per second (m3/s) (84.8 thousand cubic feet per second (tcfs)) for the month of January, effective January 4th. The outflow is being set to the normal maximum winter flow prescribed by Plan 2012, and may at times vary due to weather events and changes in hydrologic and ice conditions.
The January outflow will be released by discharging about 2,306 m3/s (81.4 tcfs) through the three hydropower plants and passing most of the remaining flow through the control structure at the head of the St. Marys Rapids. The gate setting of the control structure will be maintained at the equivalent of one-half gate open (four gates open 20 cm (8 in) each) for the month of January. The one-half gate equivalent setting is the normal winter maximum, and is typically maintained from December through April. There will be no change to Gate #1, which supplies a flow of about 15 m3/s to the channel north of the Fishery Remedial Dike.
The net water supplies to Lake Michigan-Huron were below average in December. The level of Lake Michigan-Huron dropped 8 cm (3 in) last month, while on average the lake declines 4 cm (2 in) in December. The level of Lake Michigan-Huron is 18 cm (7 in) above its long-term average beginning-of-January level, 12 cm (5 in) lower than it was a year ago, and 48 cm (19 in) above its chart datum level.
The levels of Lake Superior and Lake Michigan-Huron are both expected to continue their seasonal declines in January.
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