Bob CollinsThe Mississippi River is at some of the lowest levels we’ve seen in years. In Saint Paul, the Mississippi is only at about 3 1/2 feet, a good 8 feet below what we might normally see, and it’s about 15 feet below the spring flooding level that swallows Raspberry Island.
It’s not a huge deal this far north; the river was closed to shipping for the winter on December 3.
But it’s created quite a panic downstream.
The Army Corps of Engineers is blasting the bedrock, hoping to create enough room around Illinois to prevent a shutdown of river shipping.
Some agriculture interests fear that farmers in the Heartland won’t be able to get fertilizer for next spring’s crops. Half of the country’s fertilizer comes from U.S. plants, most of which are located near the Gulf Coast.
It costs about $10 to transport a ton of fertilizer on a barge, $25 by train, and $50 by truck.
How much rain would it take for the problems to disappear?
Wired.com’s Dot Physics blog has figured it out the usual way … with formulae that blog writers couldn’t understand if you gave them the answer.
But the answer is surprising: Only a half inch of rain per month over the entire Mississippi River watershed, which consists of most of the Midwest and Southern states.
In November, however, it only rained .02 inches. It’d have to rain every day of the month at that rate over the entire region.
