Triage: Record floods cause Army Corps to blow up levee, inundate 130,000 acres of farmland to save small town
"Triage: Record floods cause Army Corps to blow up levee, inundate 130,000 acres of farmland to save small town"
Flooding on the Mississippi in Missouri at the end of April. Image credit: USACE
File this under Annals of Adaptation:
The Army Corps exploded the Birds Point levee near Wyatt, Mo., after nightfall Monday, potentially sacrificing 130,000 acres of rich farmland and about 100 homes in Missouri to spare the town of Cairo, Ill., with its 2,800 residents, located at the confluence of the Ohio and Mississippi rivers.
But even as the Corps carried out its bid to save the city, floodwaters were rising downriver, including in Memphis, Tenn. And the breach in the Birds Point levee wasn’t expected to ease those flooding concerns.
Army Corps of Engineers Maj. Gen. Michael Walsh, who made the decision to blast, said it was a heart-wrenching but necessary move.
Here is the video of the explosion, followed by meteorologist Dr. Jeff Masters discussing the record flooding that led to it:
Masters writes about the “unprecedented Mississippi River flood“:
The fact that the Army Corps is intentionally causing 1/3 of billion dollars in damage is stark evidence of just how serious this flood is. The Birds Point levee has been demolished only once before, during the 1937 flood.
The gauge on the Ohio River at Cairo was at record highs over the past few days, but the river level is now falling, thanks to the demolition of the Birds Point levee.
Unprecedented flooding on the Ohio and Mississippi Rivers
Snow melt from this winter’s record snow pack across the Upper Mississippi River has formed a pulse of flood waters that is moving downstream on the Mississippi. This pulse of flood waters passed St. Louis on Saturday, where the river is now falling. The snow melt pulse arrived on Monday at Thebes, Illinois, about 20 miles upstream from the Mississippi/Ohio River junction at Cairo. The Mississippi River crested yesterday at Thebes at 45.52′, which beats 1993 as the 2nd highest Mississippi River flood of all-time at Thebes. This floodwater pulse is headed south to Cairo, Illinois, and will join with the record water flow coming out of the Ohio River to create the highest flood heights ever recorded on a long stretch of the Mississippi, according to the latest forecasts from the National Weather Service. Along a 400-mile stretch of the Mississippi, from Cairo to Natchez, Mississippi the Mississippi is expected to experience the highest flood heights since records began over a century ago at 5 of the 10 gauges on the river. The records are predicted to begin to fall on May 1 at New Madrid, end progress downstream to Natchez by May 15. Areas that are not protected by levees can expect extensive damage from the flooding.
The Mississippi River at New Madrid, MO, about 40 miles downstream of the confluence of the Mississippi and Ohio Rivers, crested at 46.54′ this morning, the 2nd highest flood in history. The river is now falling, thanks to the blowing of the Birds Point levee, but is predicted to rise to 50 feet late this week, two feet above the all-time record height of 48 feet. The NWS warns that at this height, “Large amounts of property damage can be expected. Evacuation of many homes and businesses becomes necessary.” Previous record heights at this location:
(1) 48.00 ft on 02/03/1937
(2) 46+ ft on 05/03/2011
(2) 44.60 ft on 04/09/1913
(3) 43.60 ft on 04/04/1975
(4) 43.50 ft on 02/16/1950
(5) 42.94 ft on 03/17/1997
The “Project Flood”
The levees on the Lower Mississippi River are meant to withstand a “Project Flood”–the type of flood the Army Corps of Engineers believes is the maximum flood that could occur on the river, equivalent to a 1-in-500 year flood. The Project Flood was conceived in the wake of the greatest natural disaster in American history, the great 1927 Mississippi River flood. Since the great 1927 flood, there has never been a Project Flood on the Lower Mississippi, downstream from the confluence with the Ohio River (there was a 500-year flood on the Upper Mississippi in 1993, though.) On Sunday, Major General Michael Walsh of the Army Corps of Engineers, President of the organization entrusted to make flood control decisions on the Mississippi, stated: “The Project Flood is upon us. This is the flood that engineers envisioned following the 1927 flood. It is testing the system like never before.”
At Cairo, the project flood is estimated at 2.36 million cubic feet per second (cfs). The current prediction for the flow rate at New Madrid, the Mississippi River gauge just downstream from Cairo, is 1.89 million cfs on May 7, so this flood is not expected to be a 1-in-500 year Project Flood. In theory, the levee system is designed to withstand this flood. But the Army Corps is in for the flood fight of its life, and it will be a long a difficult few weeks.
This is the shape of things to come, as future deluges become more and more intense — and 1-in-500 and even 1-in-1000 year events become commonplace by midcentury. We already saw Tennessee’s 1000-year deluge, and coastal North Carolina’s suffered its second 500-year rainfall in 11 years.
But we remain unprepared for the extreme weather we already have today (see “Missouri levee failure highlights need to increase infrastructure investments and prepare for climate change“).
If only someone had put forward legislation that could have funded real adaptation, so we’d be spared the other kind aka abandonment and triage and misery.
- “Real adaptation is as politically tough as real mitigation, but much more expensive and not as effective in reducing future misery: Rhetorical adaptation, however, is a political winner. Too bad it means preventable suffering for billions.”
- Conservatives oppose adaptation, too: Sen. John Barrasso continued his campaign to stop the Obama administration from incorporating climate change into federal plans and policies, taking aim at an interagency report released in October that proposed ways for the federal government to respond to increased frequency of severe weather events and other effects of global warming”¦.
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