I spend a fair amount of my time working on the logistics of moving bulk quantities (wood, wood chips, pellets) by truck, rail and barge. The simultaneous news that the Corps of Engineers is reducing Mississippi River flows from the Upper Missouri to deal with the midwest drought, and that the Great Lakes are approaching record low levels is disturbing.
Increased Midwest drought and reduced water levels in the Great Lakes have been predicted for some time by global warming models. The warmer atmosphere means that evaporation rates are increased; droughts are caused by persistent high pressures in a warmer world; decreased flow into the Great Lakes caused by reduced winter snow pack combines with increased evaporation due both to higher temperatures and to reduced winter ice cover.
What does this bode for our inland waterway transportation networks? We move huge amounts of commodities – corn, soybeans, wheat, coal, cement, asphalt, chemicals, you name it, on barges up and down the Mississippi, Ohio Missouri and Tennessee Rivers and their tributaries. We also move similar amounts of material from the upper Midwest via the Great Lakes and the St. Lawrence Seaway. While the Mississippi will not close, reduced water levels require barges to travel with less cargo per barge, greatly increasing shipping costs up and down the river systems. In addition to navigation in the main river waterways, low water closes many ports and barge terminals, especially those on tributaries of the main rivers. Last summer, one barge terminal where I was working had to be dredged three times to allow barges in for unloading. This adds to the cost of shipping, including the increase in time from loading to delivery.
Great Lakes shipping will suffer from the same problem being required to travel with lighter loads. Frank Millard of Wilfrid Laurier University estimated (pdf) that increased shipping costs on the Great Lakes would be from 5 to 22%, and up to 35% is very low water years.
We have heard a lot, and will hear more, about the impacts of reduced water levels on the ecosystems of the Mississippi River and its tributaries, and on the Great Lakes. I felt that it was important to highlight the short-term impacts on shipping costs.