Saturday, May 14, 2011

Army Corps to Open Morganza Spillway

Mississippi River floodgate to open at 3 p.m. CDT

Faced with high waters threatening to break levees and flood large areas of the Mississippi River Valley, the Army Corps of Engineers has decided to open the Morganza Spillaway and send excess water down the Atchafalaya River to the Gulf of Mexico, bypassing the Mississippi River Delta.  The spillway has not been opened in 4 decades, having last been opened in floods during 1973.  The water from the spillway will likely inundate 11,000 homes and force 25,000 to evacuate.  The opening will start at 3:00 Central Daylight Time today.

In geologic history, the main channel of the Mississippi has shifted approximately every 1000 years, making a shorter, steeper path capable of carrying more water faster.  In between, sediments build up and make the path longer and flatter.  It is generally acknowledged that the Mississippi would have changed channels in recent years to the Atchafalya, if not for the Corps building of the "Old River" Control Structure.  If the river were to shift to the Atchafalya, the New Orleans, Baton Rouge and other delta towns would soon be deprived of the ability to be used as ports, and the lower delta would degrade as sediments no longer delivered by the River would allow the delta to sink and be eroded away.  A new delta would begin grow where the new River mouth entered the ocean.

It would be an economic disaster to allow the river to shift, but it is also an expensive and probably ultimately  losing battle with nature.  After Hurricane Katrina, it seems that nature might just think that a city built on mud, below sea level is a bad idea anyway.  Maybe it's time to accept it and make adjustments.



Yeah, I know; they ain't Zep, but they're easier to look at and sound almost as good...

No comments:

Post a Comment