UPDATE ON LAKE SUPERIOR OUTFLOW - JANUARY 2015
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 2,410 cubic metres per second (m3/s) (85.1 thousand cubic feet per second (tcfs)) for the month of January, effective January 1st. The outflow is prescribed by Plan 2012, the new regulation plan for Lake Superior, which is now fully implemented as of this month.
The January outflow will be released by discharging approximately 2,316 m3/s (81.8 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 for January will be maintained at the equivalent of one-half gate open (four gates open 20 centimeters (cm), (8 inches) (in) each). 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 the setting of Gate #1 which supplies water to the channel north of the Fishery Remedial Dike.
The average flow required for navigation this month is expected to decrease due to the winter lock closure beginning January 15th.
The monthly mean water level of Lake Superior in December was 183.60 m (602.36 ft). This is 21 cm (8 in) above the long-term (1918-2013) December average and the highest December level since 1996.
For the eleventh consecutive month, the net water supplies to Lake Superior were above average again in December. The level of Lake Superior declined 6 cm (2 in) last month, while on average the lake declines 8 cm (3 in) in December. The Lake Superior level at the beginning-of-January is 24 cm (9 in) above average, 27 cm (11 in) above the level recorded a year ago at this time, and 40 cm (16 in) above its chart datum level.
The monthly mean water level of Lake Michigan-Huron in December was 176.53 m (579.16 ft). This is 21 cm (8 in) above the long-term (1918-2013) December average, the highest December level since 1997.
For the fifth consecutive month, the net water supplies to Lake Michigan-Huron were also above average in December. The level of Lake Michigan-Huron remained at about the same level as last month, while on average the lake declines by 4 cm (2 in) in December. The level of Lake Michigan-Huron is 24 cm (9 in) above its long-term average beginning-of-January level, 58 cm (23 in) higher than it was a year ago, and 54 cm (21 in) above its chart datum level.
The levels of both Lakes Superior and Michigan-Huron are expected to decline in January.