Great Lakes Study Attracted Controversy

The final report on the impact of 1962 St. Clair River dredging on Great Lakes water levels was released Dec. 15, the culmination of a year of controversy over the study’s preliminary findings that sited climate, not dredging, as the culprit for declining lake levels.

The $3.6 million study of the St. Clair riverbed was released in May. Conducted under the oversight of the International Joint Commission (IJC), a bi-national board that oversees U.S. and Canadian boundary waters, the study set out to determine whether dredging of the St. Clair by the U.S. Army Corps of Engineers in 1962 led to further erosion of the riverbed in the years since, draining more water from Lake Michigan and Huron.

The 1962 dredging was the last of nearly a century’s worth of major alterations to the river for mining and navigational purposes. The Corps has confirmed that the work increased the conveyance, or outflow, of water from Lake Huron (which is essentially the same water body as Lake Michigan) into the St. Clair and, subsequently, into Lake Erie, resulting in a 16-inch drop in the water levels of Lake Michigan and Lake Huron.

The International Upper Great Lakes Study said ongoing erosion is not the primary reason for the plunge in water levels. The study authors said erosion since 1962 accounts for no more than four to five inches of the water loss, and instead blames the rest of the water loss on climate changes, particularly a drop in rain and snowfall, and a 1984 ice jam on the St. Clair River that it says sped the outflow of water by creating more pressure.

When a hearing on the study was finally held July 7, Door County represented itself well. Dr. Eugene Stakhiv, the study’s lead author, called the crowd of 70 people who came to the Door Community Auditorium to see a presentation and ask questions “the largest and most knowledgeable” he encountered in all the hearings he presented at around the Great Lakes region.