“[Canadian] Government forecasters are projecting that Lake Superior, the largest of the five Great Lakes, will fall to its lowest level for September since modern recordkeeping began nearly a century ago. The amount flowing out of the lake at its outlet, the St. Mary’s River, has plunged too, and would have to rise by a staggering 50 per cent to reach the average of the past century.

Levels on Lakes Michigan and Huron are also sagging, Ontario is down, as is Erie – although the latter, the smallest by volume, has been the least affected.

What’s going on? While there is no scientific certainty about what’s ailing the Great Lakes – which together form the world’s largest interconnected body of fresh water – some fear global warming is at work, causing them to shrink. ”

Globe and Mail: Great Lakes Disappearing

And it’s not just changing beach front property or diminishing sport fishing….

“Record-low water levels in Lake Superior have forced shipping companies to reduce their cargoes, shrinking deliveries of coal and iron ore to manufacturers across the Great Lakes of the U.S. and Canada.

“In a normal year in August, we should be setting our best cargoes,” said Glen Neksavil, vice-president of the Cleveland- based Lake Carriers’ Association. Instead, “our vessels have been losing as much as 10 percent.”

A lack of precipitation and winter ice cover as well as insufficient dredging have reduced safe operating depths near locks and shallower waterways. Lake Superior feeds the four other Great Lakes which together hold a fifth of the world’s fresh surface water and are vital for delivering ore and coal from Minnesota and Wyoming to Detroit and Chicago.

The lower water levels, combined with an already softening economy, contributed to a 5.1 percent decline in cargo carried by U.S. vessels on the Great Lakes in the first eight months of the year, according to the Lake Carriers’ Association. The trade group represents 18 shipping companies that carry as much as 125 million tons of coal, iron ore, limestone, sand and cement a year used to make electricity and build cars and houses in the region. ”

Shipping Down