(c)Seth Perlman/AP

Portions of the longest river in America, the Mississippi, are at risk of becoming unnavigable, spelling serious economic trouble in areas from the Upper-Midwest to New Orleans since it would also block a major shipping route.

Typically the Army Corps of Engineers has been manipulating the river for decades in order to prevent it from changing its course at times or flooding the ever populated banks, through a system of levees, locks, dikes and spillways. Historically, the Corps has had its harshest runs during heavy rains when flooding occurs, the most recent major one being in 2011. Right now however things are quite the opposite.

The Upper-Midwest and consequently the Mississippi stretch have been hit by the worst and longest droughts in history. Short on water, the the shallowest stretch of the river between Cairo, Ill. and St. Louis could become unnavigable in the next month. The Corps of course are on duty, however this might prove to be challenge that is too much for them, since the matter is out of their hands.

So far the engineers have tapped all the reservoirs in the area, still it’s far from providing a significant improvement. Right now, they’ve opted for a more extreme solution – digging. By pulling rocks out of the river the engineers hope to gain one or two feet in depth at the shallowest portions in order for the route to remain navigable. The Corps is confident things are in control through out the month of January, after which the situation will pass its most critical point. Typically February is marked by rainfall and an increase of the Mississippi depth, if however the shallow portions of the river remain dry through the upcoming weeks then they risk of becoming unnavigable.

Their last line of defense is to open up the controls along the Missouri River, which would however entail draining the  Missouri basin which is already rather low. Besides that, such a decision would require  an emergency act by the President or Congress.

More info @ NPR