How Drought on Mississippi River Impacts You -- NatGeo--less freight due to the drought
Good article that includes the short-term impact of the recent oil spill
http://news.nationalgeographic.com/news/2012/12/121207-nation-mississippi-river-drought-environment-economy/
The middle Mississippi—the 200-mile (322-kilometer) stretch from St. Louis to Cairo, Illinois—is experiencing drought conditions unrivaled in the last 50 years. That's been the case since November.
Barges have had to lighten their loads considerably to avoid bottoming out. Right now barges on the middle Mississippi can only afford to sink 9 feet (2.7 meters) into the water, some only 8 feet (2.4 meters). They usually run 12 feet (3.7 meters) deep, more laden with goods to get them to market faster and cheaper
According to the American Waterways Operators (AWO), in December and January alone more than $7 billion worth of goods was at risk of not reaching their destination.
"Harvest to market also means Centralia, Illinois, to Tokyo," says Mike Peterson, a spokesman with the Army Corps of Engineers, which constructs and maintains the riverbed of the Mississippi, kind of like a watery Department of Transportation. He notes that Japan gets 90 percent of its livestock feed off the river.
As of Thursday afternoon, 52 tugs bearing 844 barges—377 headed north and 467 south—were sitting and waiting.