finished a study on this topic, due to be released on January 15, 2008. "It takes a decade or two to identify a trend in the data," she said. "There has been a drop in water levels of just a few millimeters per year since 1978. In 1997, all the lakes took an immediate drop. There has been more evaporation than snow pack runoff each year since." Yet historical data collected since the mid 1800's shows that the lakes have seen levels as low as these and even lower about every 30 years. In 1964, Lakes Huron and Michigan, connected by the Straits of Mackinac and sharing the same water level, reached a record low. Many thought the lakes would continue to decline indefinitely, but in 1986 those same lakes reached a record high. Some believe other factors may also be at work. In August 2007, a property owners group released a privately commissioned study suggesting that a 45-year-old dredging project on the St. Clair River could be at fault for low levels on Lakes Huron and Michigan. The project, which allowed heavier ships to move from the upper to the lower lakes, is now under scrutiny for causing on-going
erosion that may have increased the rate of drainage from the lakes. The St. Clair River "drain hole" theory received so much attention, that the International Joint Commission (IJC), the bi-national organization that governs the release of water from Lake Superior (the feeder lake), has expedited a study on the matter. The St. Clair River study, now due to be released in February 2009, is part of a larger IJC study that will also look at whether current lake levels are part of a larger trend. The results of the IJC's umbrella study, due in June 2009, may change the way the organization manages Lake Superior's outlet at St. Marys River and whether it is still beneficial to attempt to keep all the lakes at the same level.
Low Water + Lack of Dredging = Unusable Capacity
While some complain about too much dredging on the St. Clair, the lack of dredging in other parts of the Great Lakes, combined with low water levels, has resulted in significant light-loading. "The problem really goes back decades because the
www.marinelink.com
MN 29