click to embiggen (image: US Army Corps of Engineers)

Sometime today, the US Army Corps of Engineers will open the Morganza Floodway in Louisiana for the second time in its history. The object is to divert some of the huge flow of water coming down the Mississippi away from the usual path that streams past Baton Rouge and New Orleans into the Mississippi delta, and into a largely agricultural region of Louisiana instead. It’s a Hobson’s choice, where agricultural fields and various small towns will be flooded in order to help save many the lives and livelihoods, and communities of millions of Louisiana residents nearer to the Mississippi’s regular pathways.

A floodway is an area of relatively unpopulated land adjacent to a river, with a series of inland levees that were created to act as an emergency relief valve for the river. In times of extreme river levels, the floodway can be opened to drain off a part of the river, thus relieving the pressure on downstream levees that are protecting cities and major industrial sites.

Here in Missouri, the same decision was made with a smaller floodway a couple of weeks ago. Despite the protests of some of the farmers whose field were flooded (who apparently never read the fine print in their deeds, which allows for this to be done), the floodway was opened and the water levels in the Mississippi dropped, protecting Cairo and other cities immediately downstream. (Lots of details of how this floodway was opened here.)

When it comes to disasters, floods do as much psychological damage as they do physical damage. Earthquakes come and go in an instant, with no warning. Tornadoes and hurricanes develop in well-understood conditions, and forecasters are able to give a short amount of warning to folks in the path of the storm.

But floods . . . floods prey on your mind for weeks. It rains upstream, and rains some more, and rains some more. The waters keep rising and rising and rising some more. Sure, it’s bright sunshine and warm weather where you are, but that doesn’t matter. It’s the clouds upstream that everyone is concerned about. “Will the levees hold?” folks ask each other. As the rain continues, the question shifts ominously: “Will the levees even be high enough?”

If the levees fail or are not high enough and the water comes in, it generally stays around for weeks. Even if only your basement gets flooded, the mold takes over and the house has to be gutted if not completely demolished. Infrastructure takes a real hit, too. Roads and bridges can be impassible in high water, and also get undermined, weakened, or even totally washed away. Flooding in water treatment plants means they have to get pumped out and cleaned out before they can work, and you really don’t want to think about working on electrical lines and transformers while surrounded by water. Just getting around to work on stuff means knowing which roads are open, which bridges are safe, and which streets are navigable by what kind of boat.

For all of the “let’s bash government” stuff floating around in DC and throughout the country, think about this. NOAA and the National Weather Service have been incredible in monitoring the weather and the interplay of all the streams and tributaries of the various watershed, so that cities, counties, states, and the federal governments can take steps to prepare for what is coming. Cleaning up will be a huge undertaking as well.

This is Katrina in reverse, with the water coming from the north rather than from the Gulf. Let’s hope the lessons learned from flooding in the past that led to the creation of the floodways will help, and that the post-disaster recovery efforts that failed so spectacularly with Katrina have been improved this time around.