AuthorTopic: 🌧️ The Official Noah's Ark Thread  (Read 639 times)

Offline RE

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🌧️ The Official Noah's Ark Thread
« on: April 11, 2018, 03:23:32 AM »
https://grist.org/article/engineers-tried-to-tame-the-mississippi-river-they-only-made-flooding-worse/

climate desk
Engineers tried to tame the Mississippi River. They only made flooding worse.
By Adam Rogers   on Apr 7, 2018


This story was originally published by Wired and is reproduced here as part of the Climate Desk collaboration.

Scientists, environmentalists, and anyone who lives within a hundred miles of the winding Mississippi River will tell you — have told you, repeatedly, for 150 years — that efforts to tame the river have only made it more feral. But scientists would like more than intuition, more than a history of 18th-century river level gauges and discharge stations, more than written and folkloric memory. They would like proof.

Luckily, rivers inscribe their history onto the landscape. Which is why Samuel Muñoz, a geoscientist from Northeastern University, found himself balancing on a pontoon boat with a hole in the middle, trying to jam 30 feet of aluminum irrigation pipe into the muddy bottom of a 500-year-old oxbow lake. Muñoz and his team thought that if they could just pull up good cores of that mud, the layers would be a chronology of forgotten floods — a fossil record of the river’s inconstancy made not through petrification but implication.

Basically, the Mississippi meanders. Sometimes the river curves around so tightly that it just pinches off, cutting across the peninsula and leaving the bigger curve high, if not dry. That parenthesis of water alongside the main channel is an oxbow. In a flood, water churns up chunks of sediment and spreads into the oxbow. When the flood waters recede, the layer of coarse sediment sinks to the oxbow’s bottom, where it remains.

So Muñoz’s team humped their pontoon boat all the way from Woods Hole, Massachusetts to three oxbows whose birthdates they knew — one from about 1500, one from 1722, and one from 1776 — and jammed pipe into the lakebed with a concrete mixer. “It vibrates so hard, your hands fall asleep,” Muñoz says. “And then you have 300 or 400 pounds of mud you’re trying to get back up.” But it worked.

The cores were a map of time, with today at the top and the oxbow’s birthday at the bottom. In between: A peak of the radioactive isotope cesium-137 marked 1963, when humans started testing nuclear bombs. Using technique called optically stimulated luminescence to date, roughly, when a layer was last exposed to sunlight, they spotted classic floods, like 2011, which caused $3.2 billion in damages, and 1937, which required the largest rescue deployment the U.S. Coast Guard had ever undertaken.

The important part, though, was that the characteristics of the layers for floods they had numbers on could tell them about the magnitude of floods they didn’t. They got 1851, 1543, and on and on.

Then Muñoz’s team checked their work against another record: tree rings. Inundate an oak tree for a couple weeks and that year’s growth ring will show damage at the cellular level. So they took core samples from trees, living and dead, in the Mississippi flood plain — the oldest going back to the late 1600s. The ring damage matched. Not exactly, maybe, but close enough. They knew they were seeing floods for which no one had numbers. Muñoz’s team had created a record of Mississippi River floods two centuries older than any other. They published that work in the journal Nature on Wednesday.

Here’s where the fun part starts. Muñoz’s team then compared those floods with meteorological data — hunting for some link between flooding and climate. They especially looked at temperature changes on the oceans — El Niño events in the Pacific and Atlantic Multidecadal Oscillation. “There’s this really obvious increase in both how often the river has been flooding over the last century and how big those floods were,” Muñoz says. “The default explanation is that there’s something going on with the climate that would explain that.” There was: More El Niño meant more floods.

So climate change causes floods, right? Hah! Too easy. Muñoz’s group ran a statistical model, based on the climate over the entire period of time they now had flood records for, estimating how much more worse flooding should have gotten based on climate change alone. “It comes up with a little bit of an increase, like a 5 percent increase in how big the biggest floods should be,” Muñoz says. “But not all the increase.”

Overall flood risk has gone up 20 percent, the team says. But 75 percent of that risk comes from human engineering of the Mississippi for navigation and flood control. In other words, it’s our fault.

After a particularly devastating flood in 1927 — 637,000 people lost their homes, perhaps up to 1,000 killed, $14 billion in period-adjusted damage — human beings deployed the U.S. Army Corps of Engineers to wage all-out war on nature to protect industry, farms, and trade. People tried to warn the government even as construction began on the Mississippi’s infrastructure — channelization, dredging, dams in the upper stretch, and along the middle and lower levees, concrete mats along the banks called revetments, and gates.

“All that increases the amount of water and the speed that water goes during a flood. What we’re saying is, we can’t explain the increase we’re seeing with climate alone,” Muñoz says. “But for the first time, we can go back further, to a state in which the river wasn’t dominated by human activities. We can really show that the way the river behaves today is not natural.”

Even that look at the prelapsarian Mississippi may not change much. Warnings that flood control would lead to uncontrolled floods date back to at least 1852, when a famous engineer named Charles Ellet warned in a report to Congress that the whole idea was going to lead to disaster. Yet the U.S. Army Corps of Engineers’ Mississippi River and Tributaries Project remains in full, multi-billion-dollar effect. (Representatives for the Corps of Engineers did not return multiple requests for comment.)

Now, Muñoz’s inferential datasets don’t convince every river researcher. Bob Criss, a hydrogeologist at Washington University at St. Louis, says he doesn’t completely buy Muñoz’s team’s particle-size correlations and tree-ring cell biology. “It’s just a bunch of voodoo and sound bites,” Criss says. “I certainly don’t object to his conclusion. But I don’t think it’s robust.”

Criss definitely does buy the idea that engineering has made flooding worse, though. He says straight-ahead numbers like stage measurement (the height of the river) are enough to tell you that. Levees upriver send more water downriver. Revetments move that water faster. What might have been slow-spreading floodwaters when they were unconstrained turn into neighborhood-destroying mini-tsunamis when they burst all at once from behind failing levees.

“That’s what Charles Ellet was saying 160 years ago. This is the problem with the Army Corps. It’s like a protection racket. They just squeeze the river, make more floods, and then say, ‘Oh, let us help you, you need more help, the floods are worse,’” Criss says.

To be fair to Muñoz’s measurements, paleoflood hydrology on the Mississippi ain’t easy. (Hence the pontoon boats.) Rivers in the American Southwest that run through bedrock and canyons, for example, leave much more evident traces — sediments and other stuff that researchers can more easily excavate. That’s how paleohydrologists like Victor Baker, at the University of Arizona, can produce a 2,000 year record of Colorado River floods and a 5,000-year record of floods on river systems in Arizona. (Perhaps it will not surprise you to learn that attempts to regulate those floods has worsened them, as has climate change.)

And Baker buys what Muñoz has come up with. “Levees protect against little floods. If you have a super big flood that exceeds the capacity of the levee, the levees make that worse,” he says. There have been bigger floods than people remember — but the landscape recorded them. And if humans learn to play those recordings back, maybe we can find a new way to get ready for the waters yet to come.
« Last Edit: July 25, 2018, 03:18:17 AM by RE »
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Offline RE

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🌧️ The Official Noah's Ark Thread
« Reply #1 on: July 25, 2018, 03:17:19 AM »
Time for Surly to start building an Ark.


RE

https://www.cnn.com/2018/07/24/weather/mid-atlantic-flooding-wxc/index.html

Flooding in the Mid-Atlantic is shaping up to be 'potentially dangerous, even life-threatening'

By Ayana Archie, CNN

Updated 4:55 AM ET, Wed July 25, 2018

Four to 10 inches of rain has fallen in the region in the last three days.

(CNN)More than 30 million people from the North Carolina coast to central New York could be impacted by flooding Wednesday.
Numerous flash flood watches and warnings are in effect throughout the Mid-Atlantic after the accumulation of record rainfall in the last few weeks.
"To repeat from earlier today, this is a potentially dangerous, even life-threatening, situation," the National Weather Service tweeted Tuesday morning.
CNN meteorologist Dave Hennen said oncoming storms have been "training," or lining up, so when one is moving on, another is coming right behind it, and an area becomes plagued with water.

Northeast thunderstorms cause flash flooding, major airport delays
Northeast thunderstorms cause flash flooding, major airport delays
In most cases, this leads to atmospheric rivers, a long river-like area of water vapors in the sky that materializes as rain or snow. More rain poses a serious threat to the region, putting it at risk for flash flooding, the most severe type. Flash floods fill bodies of water extremely quickly in an unpredictable manner.
The ground is already saturated from the past 48 hours of rainfall, so this additional precipitation could cause dangerous flood conditions, said CNN meteorologist Michael Guy.
Washington has received 8.2 inches of rain since the beginning of July, while the normal amount for this period is 2.8 inches, Dennen said. The rain has fallen over eight days, as the District got no rain until July 17.

Cities in central Pennsylvania have made up 10 of the top 15 wettest areas in the 24 hours from Monday to Tuesday, with some places climbing upward of 8 inches, according to the weather service.
In Pennsylvania, as well as in most of Maryland, and parts of the Virginia and North Carolina coastlines, there is a moderate chance (20-50%) of rainfall exceeding flash flood guidance.


CNN meteorologists predict people in the area will see 2 to 3 inches of rain in coming days.

Over the last three days, 4 to 10 inches of rain fell across the region. Two to 3 inches are expected across the region through Friday night. Already saturated ground makes it hard for extra water to be absorbed.
The weather service advises people in the area to get to higher ground, if possible, avoid driving into floodwaters (12 inches of rain can sweep a car away) and to monitor media outlets for updates.
A cold front will be pushing through the eastern US, drying the area out by Thursday, Guy said.

CNN's Dave Hennen, Judson Jones, Michael Guy and Joe Sutton contributed to this story.
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Offline Surly1

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Re: 🌧️ The Official Noah's Ark Thread
« Reply #2 on: July 25, 2018, 03:31:55 AM »
I just read in the local rag ("Yesterday's News Tomorrow") that the Outer Banks has six inches of rainfall, and is looking for another ten. Here we get coastal flooding when it gets cloudy, so we're used to it. But it's rained for a week.

The flowers love it, anyhow.
“The old world is dying, and the New World struggles to be born: now is the time of monsters.”

Offline Eddie

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Re: 🌧️ The Official Noah's Ark Thread
« Reply #3 on: July 25, 2018, 06:26:56 AM »
Wow. I want some rain.
What makes the desert beautiful is that somewhere it hides a well.

Offline azozeo

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Re: 🌧️ The Official Noah's Ark Thread
« Reply #4 on: July 25, 2018, 08:38:24 AM »
Your east coast rain could persist with that hemisphere sized sand cloud coming off of the Sahara.
Supposedly, the Saharan dust is a hurricane killer & chops up the heat/humidity to where the jet stream
just deflects off of the dust cloud & heads u the east coast. 
I know exactly what you mean. Let me tell you why you’re here. You’re here because you know something. What you know you can’t explain, but you feel it. You’ve felt it your entire life, that there’s something wrong with the world.
You don’t know what it is but its there, like a splinter in your mind

Offline Surly1

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Re: 🌧️ The Official Noah's Ark Thread
« Reply #5 on: July 25, 2018, 09:15:51 AM »
Your east coast rain could persist with that hemisphere sized sand cloud coming off of the Sahara.
Supposedly, the Saharan dust is a hurricane killer & chops up the heat/humidity to where the jet stream
just deflects off of the dust cloud & heads u the east coast.

Hurricane killers are just fine by me!
“The old world is dying, and the New World struggles to be born: now is the time of monsters.”

 

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