Not what the doctor ordered. More rainfall this week for the Central Plains into the Midwest. Flood threats will be on the rise. This could be a horrific agricultural year for the FarmBelt. pic.twitter.com/m5tEXOvkCw
— Jason Furtado (@wxjay) May 26, 2019
They’re going to open the Morganza Spillway off the Mississippi River. I remember in 1973 the discussion of whether they should open a couple of gates to address the rising Mississippi, which would end up (as designed) flooding land long used for farming.
Flood management mechanisms should not be built to depend on real-time human/political judgement calls. Much better are passive weirs built into levees that allow spillway diversions based on the water level. (A notched weir allows a smaller amount of near-continuous outflow for lower water levels, but acts as a flood spillover if the water gets high enough.) Other passive flow-control structures maintain deeper channels to reduce the need for dredging.
In the world of litigation and blame, active control means that people have to make explicit decisions on whether to flood someone’s land or town. Passive design means you make sure everyone knows that the river will flood this land when it gets high enough.
The other goal is to avoid catastrophic levee (or dam) breaches by designing in passive “controlled failure” for extreme conditions.
Far too logical.
Another thing: Rather than Edie Brickell, I’d have chosen Irma Thomas (It’s Raining) or Tina Turner (I Can’t Stand the Rain).
How about “5 Feet High and Rising” by Johnny Cash https://www.youtube.com/watch?v=14zHgCrywjU.
Or “River Take Me” by Darrell Scott