• The Mississippi: A Visual Biography by Quinta Scott

    "Great book and great blog - thanks for the first book I have seen that addresses the contemporary river, headwaters to gulf." Dan McGuiness, Audubon, St. Paul, Minnesota

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The Flood of 2011 and the Atchafalaya Delta

“Artificial levees, extending clear to the Gulf of Mexico, may have made human habitation of the delta south of Cape Girardeau possible, but prevented the Mississippi from refreshing its marshes with its sediment when it did flood. Revetments built of concrete mats may have stabilized the navigation channel, but reduced erosion of the banks, a source of sediment in the marshes. James Eads’ jetties at the mouth of the river may have allowed the river to cut a thirty-foot navigation channel through the sandbar blocking the South Pass of the modern delta, but delivered sediment carried by the river to very deep water at the continental shelf, where it washed away, never to be used for marsh building. Closure of the old distributaries of the river may have prevented flooding in the bayou country of Louisiana, but cut the flow of Mississippi sediment to the coastal marshes. Channel dams may have made navigation on the Upper Mississippi profitable, but they retained its sediment north of Alton, Illinois. Dams on the Missouri, from which the Mississippi drew sixty percent of its sediment, did the same. In short at the beginning of the twenty-first century, the coastal marshes south of New Orleans received eighty percent less sediment than they had at the beginning of the twentieth and eroded away.”

I haven’t counted the number of posts I have begun with this quote from The Mississippiand I am doing so again.

Morganza Floodway Structure

Twice, 1973 and 2011, since it was constructed after the Flood of 1927, we have opened the Morganza Floodway Structure to release flood water from the Mississippi into the Atchafalaya River and Floodway. After the Flood of 1973, geologists noted that the Atchafalaya River was building land at its mouth, using all that mud funneled down the Mississippi from erosion from the Midwest and the South.

With this in mind geologists from the University of Pennsylvania–joined by others from the University of Mississippi, Louisiana State University, and the U.S. Geological Survey–began studying the sediment plumes that spewed out of the Mississippi, the Atchafalaya River and Wax Lake Outlet, and through the Bonnet Carre Spillway into Lake Pontchartrain during the Flood of 2011.

Sediment Plumes from the Atchafalaya, Mississippi, and Bonnet Carre

Atchafalaya Delta, 2009

The Atchafalaya slowly spread a wide plume of sediment in to Atchafalaya Bay, where it is building land. The Mississippi, which is too long and too flat and is hemmed between levees, is shooting its mud over the edge of the continental shelf, where it is useless for landbuilding.

Wax Lake Outlet Delta

Similarly, the Wax Lake Outlet, an artificial outlet from the Atchafalaya Basin, built to reduce flooding in the basin, is building its delta.

What is happening in Atchafalaya Bay is what happened naturally before we reengineered the Mississippi for flood control and navigation. Now that we have done it, we have to live with the consequences and find ways to restore Louisiana’s coastal wetlands by mimicking the river’s ways. The Atchafalaya is an example. So is the Mardi Gras diversion at Bohemia, which opened up into Breton Sound this spring during Mardi Gras.

The Mississippi Ridge at Bohemia south of the end of the main line levee

The question about the Mardi Gras Diversion is whether we are going to keep it or dam it. It is an example of what is being done on a small scale and can be done on a large scale along the Mississippi south of New Orleans.

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Mardi Gras Pass: Keep it or Dam It

Mississippi River Ridge at Bohemia

While folks partied in the streets of New Orleans on Fat Tuesday, the Mississippi River gave the State of Louisiana a gift, a freebie. The river broke through the low ridge at Bohemia, south of the end of the Main Line levee, and began pouring sediment into Breton Sound to the east. The river is doing for free what the state would have the Federal Government pay $50 billion over 50 years to rebuild barrier island and to divert the Mississippi to Breton Sound on the east and the Barataria Basin on the west. State engineers already had a plan on the books to create a similar diversion into Breton Sound a mere mile from the Bohemia siphon, where the breach occurred.

Bohemia Siphon along the Mississippi

The site of the breech was the old, inoperable siphon, designed to deliver fresh water from the river to the wetlands in the sound. The siphon opens onto a spillway, created in 1924 as a means of relieving flooding in New Orleans. However, this spillway is 45 miles south of New Orleans. After the Flood of 1927 the Bonne Carre Spillway and the Achafalaya and Morganza Spillways were design to siphon water from a flood Mississippi before it reached New Orleans.

Sites of Bohemia Siphon and the Oil Facility on the End of the Road on the Mississippi Ridge

Now the U.S. Army Corps of Engineers has given Houston-based Eland/Sundown Energy permission to seal the crevasse, dam it in order to rebuild the road to their work facility not more than two or three miles down the road, where it ends at a gate to its yard.

Right now the Mississippi is low, very low and the spillway is delivery fresh water and sediment at a much slower rate than the 50,000 cubic feet per second the state-designed spillway would flow. But water and sediment is flowing to Breton Sound. It is a gift from the Flood of 2011. The river will rise again, flood, and spill more water through the breach, enlarging it and sending more water and sediment to the Bohemia Wildlife Management Area and Breton Sound.

Breton Sound at the Bohemia State Wildlife Management Area just off Pointe a la Hache

In 2005 Katrina roared across the Mississippi south of the siphon, and tore north through Breton Sound and Lake Borgne tearing up the wetlands and busting through the levees that protected St. Bernard Parish, trashing the towns there. Then it tore across the wetlands that protects that lovely string of towns on the the State of  Mississippi coast–Bay St. Louis, Pass Christian, Gulf Port, and Biloxi–and destroyed them. Had those wetlands in Breton Sound been in tact, Katrina would not have been as devastating. Never mind what happened after it arrived in Lake Pontchartrain, washed into the canals that drain every drop of water that falls on New Orleans, and collapsed the levees that contained them, flooding the city.

  •  (quintascott.wordpress.com)

1 Mississippi, Wild Miles, and the Restore Act

Roseau Cane, Delta National Wildlife Refuge, 2005

Cruise the roseau canyons of the Delta National Wildlife Refugeand enjoy what Louisiana offers right at the edge of the Gulf of Mexico. While protected from the oil that BP poured into the Gulf of Mexico two years ago, the Pass a Loutre Wildlife Management Area, just to the south of the Delta refuge, took the brunt of the oil and parts of it are still closed.

Louisiana Department of Environmental Quality Image of Oil easing into Pass a Loutre Wildlife Management Area

Pass a Loutre and the interior wetlands and barrier islands at the edge of the Gulf of Mexico are Louisiana’s first line of defense against hurricanes, and as we learned in 2010, against gushers of oil.

Timablier Island at the Gulf of Mexico

1 Mississippi, founded in September 2011, is once again urging its members and others to write their Congressional representatives to urge them to vote yes on the Restore Act, to restore the Gulf of Mexico and the Louisiana Coastal Wetlands as well as those in Mississippi, Alabama, and Florida. It’s a tall order, because the deterioration of the Louisiana Coastal Wetlands is becoming critical. Katrina taught us how vulnerable New Orleans has become to massive hurricanes. Restoring the wetlands south of the city would do much to protect it. Click here to urge you representatives to vote yes on the Restore Act.

In addition 1 Mississippi had a recent article on the work of John Ruskey and Mark Clark of the Quapaw Canoe Company in Clarksdale, Mississippi to show us the Wild Mississippi at WildMiles.org. These gentlemen are canoeing the Mississippi from St. Louis south and documenting the wild places along the river and putting their images on their blog, WildMiles.org.

Big Sunflower River at Holly Bluff

Quapaw Canoe first started showing people the beauties of the Big Sunflower River, which heads not far from Clarksdale. Now they are showing us the beauty of the wild lands on the banks of the Middle and Lower Mississippi. And they are not easy to get to. I live on the uplands two or three miles from the Middle Mississippi and without their canoe I have to travel across privately-owned wheat, corn and soybean fields to get to the banks of the river. When I was working on The Mississippi, I found almost impossible to get to the bank of the Lower Mississippi.

Chartre Island Snake

Only Chartre Island is accessible from the mainland and only when the river is down and I can hike the dike across the Chartre Island Side Channel. Once on the island I could find no trail that would take me to the bank of the river.

Chartre Island Side Channel

The New Orleans Levees

Six Flags, New Orleans, February 2007

Sandy Rosenthal, the director of Levees.Org, has been running a one-woman crusade to persuade national and local journalists to understand that the flooding of New Orlean during Hurricane Katrina was not an act of God, but a massive engineering failure of poorly designed and incomplete levees and to write about Katrina from that point of view–every time. Last weekend she put up a post on Huffington Post, and asked those of us who are interested in the Mississippi River and the Louisiana Coastal Wetlands that the river created to comment on her post. It was quite a campaign: fifty-three people commented. Some put their comments on their facebook pages to which 179 gave a thumbs up.

I wrote:

Any journalist who writes about the collapse of the New Orleans levees on August 29, 2005 should first read the Investigation of the Performance of the New Orleans Flood Protection Systems in Hurricane Katrina on August 29, 2005 by the engineering team from the University of California, Berkley. And if said journalist chooses not to plow through that two volume tome, said journalist should at least read the executive summary.

Ivor van Heerden and Team Louisiana, which also examined the destruction of the levees, designed after Betsy in 1965, “declared that the Corps of Engineers managed the hurricane levees in Greater New Orleans “like a circa 1964 flood control museum,” and continued to use design criteria set in 1965 even though much had changed in the intervening forty years. The Corps ignored that local sea level had risen 0.4 feet in the intervening forty years and New Orleans had sunk 1.5 feet. Add them together and the engineers were designing and maintaining levees for a city that was laying two feet lower in the landscape, relative to sea level, than it had in 1965. Hence, the crowns of levees were up to six feet too short, leading to prolonged overtopping during Katrina.” –from The Mississippi: A Visual Biography, University of Missouri Press, 2010

Nashville Underwater

I’m going to leave Louisiana and the BP oil spill behind for today to ask this: Has anybody noticed that American cities are being flooded, really flooded, with disturbing regularity?

While we were distracted by the big BP oil slick in the Gulf of Mexico and the car bomb discovered in Times Square, another American City went under water. The Cumberland River flooded and inundated Nashville’s downtown.

I started serious work on The Mississippi: A Visual Biography in June 1993, when the Great Midwestern Flood chased me down to work in the Lower Mississippi Valley. No large city went flooded during that flood, though many small communities did. My friends in Monroe County, Illinois swear that the Corps of Engineers created the levee break at Columbia, Illinois that flooded their farm fields in the American Bottom in order to relieve pressure on the flood walls in St. Louis.  While the evidence doesn’t bare that out, parts of northern and southern reaches of the city did dodge a bullet in 1993.

An American Bottom cornfield, where the corn stalks broke off a the flood level, January, 1994

In  April 1997 Grand Forks, North Dakota went underwater and stayed underwater when the Red River of the North flooded the city. The flood did not drain away until ice in Lake Winnebeg, the remnant of Lake Agassiz through which the Red River flows, melt. The catastrophic floods that drained glacial Lake Agassiz that covered much of  northern North Dakota, Minnesota, and southern Manitoba  had a hand in setting the course of the modern Mississippi.

In 2001 Davenport, Iowa, which would rather enjoy its view  of the Mississippi that look at a concrete floodwall, was inundated because the levees that protect Rock Island, Illinois on the opposite bank pushed the floodwaters its way.

In 2005 New Orleans flooded because the Corps of Engineers built inadequate floodwalls along the drainage canals that deliver every drop of water that falls on the city to Lake Pontchartrain. Actually, New Orleans flooded because we Americans have made a whole series of disastrous decisions about how we manage the Mississippi and the Louisiana Coast, starting with the first levees built along the river at New Orleans in 1723.

It was a 500-year flood that soaked Cedar Rapids, Iowa in 2008, when the Cedar River rose 12 feet above flood stage on June 13 with the expectation that it would go three feet higher before easing off in a week or so.

It was a 500-year flood that soaked Nashville last weekend. The  news reports coming out of the city sound like those that came out of New Orleans five years ago: Bodies are being discovered at the floodwaters recede.

In checking topo maps on Terra Server I find that neither Cedar Rapids nor Nashville has levees or floodwalls protecting their riverfronts. Neither thought they needed it. And, like Davenport, who wants to look at an ugly floodwall or live behind a tall levee?

We Americans have yet to sort out how we are going to manage our rivers so these floods do not destroy our cities.

The Realities of the Mississippi, the Missouri,the Atchafalaya, the Louisiana Coast, and New Orleans

Last week a pair of geologists, at the University of Texas, Austin, proposed diverting the Mississippi and its sediment to Breton Sound on the east and Barataria Bay to the west in order to build new deltas in each body of water.

 

DiversionIllustration

Illustration from Science Daily, (Credit: AGU/EOS)

They would make the diversions about ninety miles south of New Orleans, my guess near Grand Bayou on the west, where the Mississippi levee runs, and Bohemia on the east, where the Mississippi River levee ends.

 

Bohemia

Mississippi River Ridge at Bohemia

Like other who have proposed Mississippi River diversions to build land in Louisiana, they have looked at the landbuilding that is going on at the mouth of the Atchafalaya River and the Wax Lake Outlet from the Atchafalaya Basin. Since the completion of the Old River Control Structure in 1962, the Atchafalaya has funneled off 1/3 of the Mississippi water and sediment at Old River, about 200 miles north of New Orleans. The Atchafalaya also carries all of the Red River and its sediment to the Gulf of Mexico, where it is building new land. Last summer the New Orleans District of the Corps of Engineers announced it would study changing the ratio of Mississippi to the Atchafalaya with an eye to diverting more water and sediment to the Atchafalaya.

It should be noted that the Corps built the Old River Control Structure to keep the Mississippi from diverting to the Atchafalaya on its own in its effort to find a shorter, steeper route to the Gulf of Mexico.

 

OldRiverControl

Old River Control Structure

All of this runs in the face of a paper published four months ago by a pair of geologists from Louisiana State University, stating that there is not enough sediment in the Mississippi to rebuild the Louisiana Coast. It’s all trapped behind dams in the Mississippi River basin, dams designed sometimes to retain floodwater in the uplands until the Mississippi and its tributaries could handle them, and built sometimes because the Corps of Engineers could and Congress approved.

Carl Pope, Executiver Director of the Sierra Club, put all this in perspective in an article at the Huffington Post. He came away from the Ecumenical Patriarch’s Eighth Religion, Science and the Environment Symposium with his own take on the state of the Mississippi River, the Missouri, the Atchafalaya, the Louisiana Coast, and New Orleans: they are all of a piece. The only way we are going to save the Louisiana Coast and New Orleans is to release the sediment, trapped behind dams on the Missouri, which supplied 60% of the mud to the Mississippi in 1900, and allow it to flow down the Mississippi/Atchafalaya and build land along the Louisiana Coast. This sediment is needed to keep up with the rise in sea level, which will come as Arctic ice melts.

To get the sediment to the coastal wetlands, something will have to be done about the levees that keep the Mississippi spilling over into the Louisiana parishes south of New Orleans. And, the river needs more room to flood north of New Orleans, where it is hemmed between levees–that protect cotton, corn, and soybeans–clear to the mouth of the Missouri River and above, where the Flood of 2008 breached agricultural levees in northern Illinois and farmers want a 500-year levee to protect their fields. New Orleans may get a 100-year levee someday.

Copyright © Quinta Scott, 2009, All Rights Reserved

MRGO is Closed but not Gone

The Katrina Memorial at MRGO and Bayou La Loutre

The Katrina Memorial at MRGO and Bayou La Loutre

I am working on the index and page proofs for my book on the Mississippi River, how it was formed, what we have done to change it, and how we are trying to restore it.

Hence, I present you with an oldie, but goody: MRGO. Go to my catagories section and find the other postings on MRGO.

The Corps of Engineers has finished closing MRGO, using 352,000 tons of rock to build a dam across the hated navigation channel.

But MRGO is not gone. The dam is a speed bump, something for a hurricane lake Katrina to trip over, but not slow it down considerably. None of the marshes that were destroyed by its construction and enlargement have been restored. St. Bernard Parish still depends on levees for hurricane protection and the levees have yet to be protected by marshes. The dense cypress forest that once protected New Orleans along Bayou Beinvenue is still gone. It will take thirty years or more to grow and a forest that will offer effective protection to the city.