I’ve mentioned that water levels in the Great Lakes have declined recently, and that this is probably related to climatic factors like recent droughts. Low flows on the Mississippi River suggest that droughts are, indeed, a big factor in the upper Midwest right now. In fact, the Army Corps of Engineers is trying to manage the reservoirs on the Mississippi and Missouri Rivers to balance conservation and water flow. Their latest decision to keep more water stored in an upper Missouri reservoir may mean that barge traffic on the Mississippi near St. Louis and Illinois may shut down early next year, absent heavy rain/snow. The Missouri River flows into the Mississippi River just north of St. Louis, and in a normal year, up to 60% of the combined flow comes from the upper Missouri watershed. This year, however, approximately 78% of the combined flow has come from the upper Missouri — which means that the flow from the upper Mississippi (Minnesota, Iowa, Illinois, and even Lake Michigan) is a mere 22% of the flow. In other words, the upper Mississippi makes up a smaller piece of the pie than in a normal year, plus the whole pie is smaller than a normal year. Rough times.
There’s not much to be done in the midst of a drought except draw down our reservoirs (this is why we save up our water every wet year) and increase dredging to deepen existing shipping channels. But I can say that this saga tells us that the problems of the Great Lakes are not due to a couple of extra diversions here and there — the middle of the country is in a tough drought, and there’s less water to go around. Another year like this, and we’ll be praying for rain.