Drought conditions have resulted in significant drops in water levels not only in the Mississippi River but in a key tributary, the Missouri River. Last week, the Army Corps of Engineers (Corps) began reducing flows from the Missouri River reservoir, a move anticipated to further lower water levels in the Mississippi River and potentially halt barge traffic within the coming month.

In a move required to protect the Missouri River basin, the Corps has started reducing flow to the Mississippi River from 37,500 cubic feet per second to 35,500 cubic feet per second. By December 11th, the flow will be reduced to 12,000 cubic feet per second.

The Mississippi River is nearing historic lows between St. Louis, Missouri and Cairo, Illinois. Barges are already required to carry lighter loads and the middle of the river could be closed to barge traffic if the water level at St. Louis dips below minus 5 feet. It was at minus 0.45 feet Friday, November 23rd.

Barges carry 20 percent of the country's coal and more than 60 percent of its grain exports. Other cargo, including petroleum products, lumber, sand, industrial chemicals and fertilizer, also gets shipped along the Mississippi River.

Barge operators and those who ship on the Mississippi have warned that a shutdown would have disastrous economic consequences on those industries, with companies laying off workers if it lasts for any significant amount of time.

Governors of states along the Mississippi River,  members of Congress and river shipping trade groups have even asked President Barack Obama to intervene.

The 2012 drought already has hurt recreational use of the Missouri and Mississippi Rivers as well as diminished Corn Belt yields. Now drought conditions may impact the capability of getting the minimal crop to market and obtaining fertilizers and fuel needed for Spring planting, if barge traffic is stopped.

Water stress is a growing challenge in the U.S. The water levels in the Mississippi and Missouri Rivers are the latest example of water scarcity concerns existing today resulting from changing and volatile weather patterns like this year's drought. Most now agree that climate change is at least part of the reason for these changing weather patterns.