Those of us who live along and near the confluence of the Illinois, Mississippi and Missouri rivers are more accustomed to problems with too much water rather than too little.

This area was the heart of the Great Flood of 1993, which turned much of the Midwest into one giant lake. While 1993 wasn't the first great flood on the Mississippi (1927, 1937 and 1973 also were big ones), it remains the standard for many communities along the river. And the floods have kept coming, as in 2002 and 2008, and another huge one as recently as 2011.

That makes the situation in 2012 all the more perplexing. How can the river be near record high levels one year and now setting record lows the next?