Great Lakes Basin Higher Than a Year Ago
By IUGLSDec 15, 2011
Photo by Sharon Mollerus
A recent sharp rise in water levels on Lake St. Clair was due to heavy rainfall, while the Great Lakes as a system remain in their seasonal decline. The basin, however, is higher than at this time a year ago.
Newly released data from Environment Canada indicates that Lake St. Clair’s level rose by 25 centimeters (almost 10 inches) in November. Usually, the lake between Huron and Erie declines by about 7 cm during the month. The rise was attributed to heavy rainfall in the basin during the last week of November.
Lake Erie’s level also rose by 6 cm during the month, in contrast to its average decline of 5 cm for November. That also was attributed to above-average rainfall in late November, with below-average inflows from the Detroit River and above-average inflows from the Niagara River. Other lakes were down during the month. Superior declined by 4 cm, near its average decline of 5 cm for November. Michigan-Huron dropped by 4 cm, matching its average for the month. Ontario declined by 7 cm, more than twice its average decline of 3 cm.
While the Great Lakes are higher than at this time in December 2010, the levels of Superior and Michigan-Huron remain below their long-term average levels. Lakes Erie and Ontario are at above-average levels, according to Environment Canada.
A separate forecast from the U.S. Army Corps of Engineers in Detroit says levels on all the lakes are projected to decline during the month of December.
Lake Ontario is expected to rise by 2.5 cm during the final month of 2011.