The Disappearing of Louisiana, Part 5: The Control of Nature: Atchafalaya

The Atchaflaya River wants to capture the Mississippi River, and the Mississippi River wants to get caught.

But we are doing all we can to stop that union.

Old River Control Structures. Source: Urban Decay. Credit: US Army Corps of Engineers.

Not long after I moved to Louisiana in late 2013, one of my cultural informants, Michel, turned me on to a 1987 article: The Control of Nature: Atchafalaya.

It was written by John McPhee, published in The New Yorker.

The Control of Nature: Atchafalaya is long, but engrossing. It is WELL worth an investment of reading time.

But if you're in a super hurry, here's a fast-food, go-down-so-easy tasty video on the relentless struggle for control between us humans and the alliance of the Mississippi and Atchafalaya Rivers  below: Go ahead, watch it. It's only a couple of minutes long.

Why does this all remind me of an old 1960s song:

Atchafalaya

There's the:

1. Atchafalaya River, 
2. Atchafalaya Basin, aka Atchafalaya Swamp, and 
3. Atchafalaya Bay, aka Delta

The word "Atchafalaya" comes from the Choctaws, meaning "long river." The river is the 5th largest in North America by "discharge."

If the Mississippi were allowed to flow freely, the Atchafalaya would capture the main flow of the Mississippi, permitting the Mississippi to bypass its current path through Baton Rouge and New Orleans. (Credit: wikipedia)


Below is an archival movie, not about the Atchafalaya, but its favored sister, the Mississippi

The River (1937), still shown in academic venues today, for its historic, environmental, anthropological, economic, and artistic values:

"Shows the importance of the Mississippi River to the United States, and how farming and timber practices had cause topsoil to be swept down the river and into the Gulf of Mexico in the late 19th and early 20th centuries."

The narrative is an epic poem. Of beauty, of construction and destruction, of movement, transition, of change.

There is an image sequence of an axe chopping into the side of a living tree; it has the appearance of an assault on flesh. The suspenseful photography, narration, and sound to describe the birth and maturation of a flood builds a thrilling fear into the viewer.

Ah, the ending --> An eloquent manifesto of how we've damaged the Mississippi River Valley. But then, in the tradition of "the road to hell is paved with good intentions," the narrator concludes with this foreshadowing of unintended consequences:

"Flood control of the Mississippi means control in the Great Delta ... and the Old River can be controlled .. We had the power to take the Valley apart, we have the power to put it together again. In 1933, we started .... " 

Related posts

Disappearing Louisiana, Part 1: Stumbling on History
Disappearing Louisiana, Part 2: Water Words
Disappearing Louisiana, Part 3: Paradise Faded: The Fight for Louisiana
Disappearing Louisiana, Part 4: Revetments, Rip-rap, and Other Exotica
Disappearing Louisiana, Part 5: The Control of Nature: Atchafalaya

The Disappearing of Louisiana, Part 4: Revetments, Rip-Rap, and Other Exotica

Mississippi River, Alton, Illinois. May 2011.

My intermittent series on "the disappearing of Louisiana" is about the effects of nature and man on Louisiana's land and waters. Restore or Retreat says that Louisiana loses 25 to 35 square miles of land a year, nearly a football field every hour.

Mississippi River, Alton, Illinois. May 2011.

Where does the land go? ...... It is sinking under water. It is drowning.

To get a handle on all this, I need to learn new words such as those to describe ways to protect coastlines or defend against high water:

Breakwaters: A breakwater is an "offshore structure which is aligned parallel to the shoreline. A fixed breakwater refers to one generally constructed of stone ... . Floating breakwaters [are] firmly anchored and may be constructed of tires, logs, ...  or other floating materials."

There doesn't seem to be consensus on the efficacy of breakwaters, as they can cause collateral problems.

Breakwaters from Ahmed Abdelsalam

Freeboard: "The height above the recorded high-water mark of a structure (such as a dam) associated with the water." In construction on land, "freeboard is elevating a building's lowest floor above predicted flood elevations by a small additional height, [such as] 1-3 feet above National Flood Insurance Program minimum height requirements."

Revetments: "Structures placed on banks or bluffs in such a way as to absorb the energy of incoming waves. They are usually built to preserve the existing uses of the shoreline and to protect the slope. Like seawalls, revetments armor and protect the land behind them." 

Revetment design. Credit: Pile Buck Magazine

There are different kinds of revetments. For example, in the New Orleans area, the Corps of Engineers use concrete mat revetments and trenchfill revetments. 


Riprap. Here is a rather grand definition of riprap from Arundel Marine: a protective mound of stones, randomly placed to prevent erosion at a structure or embankment. ... And here is a more prosaic description, which I adapted from wikipedia: rubble used to armor a shoreline.  It feels good to say rubble and riprap in one sentence and have it actually mean something. 

Shoreline protection Cypremort Point State Park, Louisiana

The difference between breakwaters and revetments: "In coastal engineering, a revetment is a land backed structure whilst a breakwater is a sea backed structure (i.e., water on both sides)." Source: wikipedia.



Sills: A sill is a "perched beach," where a beach is built up to be at a higher level then the water.

Sills. Credit: NH Coastal Adaptation Workgroup

Related posts

Disappearing Louisiana, Part 1: Stumbling on History
Disappearing Louisiana, Part 2: Water Words
Disappearing Louisiana, Part 3: Paradise Faded: The Fight for Louisiana
Disappearing Louisiana, Part 4: Revetments, Rip-rap, and Other Exotica
Disappearing Louisiana, Part 5: The Control of Nature: Atchafalaya

The Disappearing of Louisiana, Part 3: Paradise Faded: The Fight for Louisiana

Part 1: Stumbling on History
Part 2: Water Words



This 2007 documentary by Jared Arsement hammers in four solid messages:

1. South Louisiana is a strategic location for the reliable production and delivery of oil and gas to the United States, for fresh- and saltwater fishing, the export of midwestern agricultural products, and for the mitigation of weather-related disasters. 
2. Louisiana is literally disappearing into the sea, being subsumed by the Gulf of Mexico.
3. The disappearance of Louisiana results in the loss of people's land, homes, livelihoods, and the protection of major population centers from storms.
4. There are remedies to stop the disappearance, but there is insufficient political will to do so. 

Notes from the documentary: 

Every grain of soil that created the land mass we call Louisiana came from the American east and midwest.

Before 1927, the Mississippi River was like a hose filled with water that moves from side to side, distributing water and silt in a wide swath. 

Louisiana was a by-product of natural flooding.

Since 1927, instead of distributing the sediment throughout Louisiana, it all goes straight to the Gulf of Mexico. (This is because the Mississippi River was channelized.)

Between 1932 and 2000, Louisiana lost nearly 2000 square miles of wetlands. This is the size of Delaware.

Note: My understanding is that as it pertains to Louisiana, the "loss of wetlands" does not mean that there is still land where there used to be wetlands, and that it's just a different quality of land. My understanding is that there is no land, period. It is underwater. Hopefully someone will correct me if I'm mistaken.

Coastal Louisiana. Land loss/gain 1932-2050. Credit: USGS

Note: The red in the graphic above = land lost between 1932 and 2000. Light gray = land gained. Yellow = projected land loss by 2050. Green is projected land gain by 2050.

In the 1950s and 60s, thousands of miles of canals were dredged to accommodate the oil and gas pipeline needs. It likely was not known at that time that the canals would widen because of the dredging, which created deeper and straighter paths for fast water to travel, resulting in bank erosion and channel deepening, which made the canal deeper and wider, which enabled faster water, which ....

Southeast Louisiana. Land loss 1932-2050. Credit: USGS

 A system disintegrated: 

In the past, natural barriers protected Louisiana from the worst of storm destruction: 

1. Front line defense: Barrier (or channel) islands -> drowning in the Gulf
2. Second line of defense: Wetlands --> drowning via erosion and invasion of Gulf waters
3. Third line of defense: Levees --> by themselves, they aren't plentiful enough, stable enough, or high enough to protect people and infrastructure

How do they help? 

Barrier (or channel) islands are like speed bumps - they slow the progress of a tropical storm. 

Barrier islands are narrow strips of land that parallel the coastline and consist of a variety of fine sediments and particulate matter. A barrier island is separated from land by a shallow bay or lagoon and can stretch for tens of miles.

Barrier islands are narrow strips of land that parallel the coastline and consist of a variety of fine sediments and particulate matter. A barrier island is separated from land by a shallow bay or lagoon and can stretch for tens of miles. Source: Rockbandit.

Barrier islands are narrow strips of land that parallel the coastline and consist of a variety of fine sediments and particulate matter. A barrier island is separated from land by a shallow bay or lagoon and can stretch for tens of miles.

How barrier islands protect mainland. Source: University of Texas.

In turn, the wetlands suck energy from the storm by:

• Reducing wind speed; and 
• Adding friction to the surge, slowing it and weighing it down

From article in Times-Picayune. Graphic credit: SE Louisiana Flood Protection District

2.7 miles of wetlands can reduce storm surge by one foot. 

The levees protect people and property (if the islands and wetlands are there to do their part).


Remedies

Talking heads in the documentary cited: 

• Small and large diversions from the Mississippi River channel as it drops through Louisiana (to recapture sediment that is otherwise dumped through into the Gulf) - this would maintain and rebuild land. 
• Opening and closing channel gates using the Dutch model of flood management 
• Restoration of barrier and channel islands

Henry Hub

Henry Hub is in/near the small town of Erath, Louisiana.

To illuminate the strategic importance of Louisiana's geological stability, the documentary noted the Henry Hub, place where natural gas prices are set.

From investopedia: 

A natural gas pipeline located in Erath, Louisiana that serves as the official delivery location for futures contracts on the NYMEX. The Henry Hub is owned by Sabine Pipe Line LLC and has access to many of the major gas markets in the United States. As of June 2007, the hub connects to four intrastate and nine interstate pipelines, including the Transcontinental, Acadian and Sabine pipeline.

The Henry Hub pipeline is the pricing point for natural gas futures on the New York Mercantile Exchange. The NYMEX contract for deliveries at Henry Hub began trading in 1990 and are deliverable 18 months in the future. The settlement prices at the Henry Hub are used as benchmarks for the entire North American natural gas market.

The take-away 

In addition to defining the issues, the documentary made these clear arguments for the fixes:

• Louisiana has the knowledge, experience, and technology to freeze or roll back the disappearing of Louisiana. 
• Louisiana doesn't have the money to do it. 
• At the time the movie was made (2007), there wasn't the national political will to help Louisiana do it. 

Louisiana argues that this is not a Louisiana emergency - it is a national emergency.


Related posts

Disappearing Louisiana, Part 1: Stumbling on History
Disappearing Louisiana, Part 2: Water Words
Disappearing Louisiana, Part 3: Paradise Faded: The Fight for Louisiana
Disappearing Louisiana, Part 4: Revetments, Rip-rap, and Other Exotica
Disappearing Louisiana, Part 5: The Control of Nature: Atchafalaya

The Disappearing of Louisiana, Part 2: Water Words

The Zen of Flowers and Refineries, by Raina Benoit. Lafayette, Louisiana. 

To get a handle on the disappearing of Louisiana, I need to educate myself on water words. Unless quoted by an attributed source, everything below is based on my (flawed) understanding of water terms. 

Wetlands

1.      "Wetlands" is the parent category for these subcategories:

• Swamp
• Marsh

(there are more, but I'm trying to keep it simple)

2.      Wetland

An area that is inundated or saturated by surface or groundwater at a frequency and duration to support ... a prevalence of vegetation typically adapted for life in saturated soil conditions

3.     Swamp

 a wetland that is forested ... Many swamps occur along large rivers where they are critically dependent upon natural water level fluctuations. Other swamps occur on the shores of large lakes. [I added the boldface for emphasis.]

4.     Marsh

A type of wetland that is dominated by herbaceous rather than woody plant species ...
Marshes can often be found at the edges of lakes and streams, where they form a transition between the aquatic and terrestrial ecosystems. They are often dominated by grasses, rushes or reeds

Wetlands are important because they: 

• Help mitigate the effects of river flooding and hurricane-led coastal surges
• Protect water quality by trapping contaminants on the wetlands floor
• Protect shorelines from erosion

Cypress swamp, Natchez Trace, Mississippi.

Bayou

A bayou is a slow-moving creek or a swampy section of a river or a lake. They are usually found in flat areas where water collects in pools. Bayous are often associated with the southeastern part of the United States.

Bayous are usually shallow and sometimes heavily wooded. They can be freshwater, saltwater, or a combination of both. This combination is called "brackish water." Source: National Geographic Education

The Bayou Teche may be south Louisiana's most prominent bayou. Thousands of years ago, it was the main channel (see below) of the Mississippi River. Bayou Teche is 125 miles long and feeds into the Atchafalya River.


Tributaries v. distributaries

• A tributary is a freshwater stream that feeds into a larger stream or river. 
• A distributary is a stream that branches off and flows apart from the mainstem of a stream or river. 

 Source: National Geographic Education

Another description:  Rivers are connected together in vast networks of tributaries, which feed water into the main river channel, and distributaries, which pull water out of the main channel.


Channel

The channel isn't the water; it is the container of the water - the bottom and sides of the river, for example. The banks of a river are part of the channel.

The above is a neutral definition of a channel. Some channels are man-made. Canals and ditches are man-made channels.

A man-made channel is a double-edged sword. It can control the passage of water and can prevent some floods. On the other hand, water moves through a man-made channel faster (thus stronger) than a natural channel. Consequently, when water does top the channel banks, it is a more dangerous flood because its force is stronger than it would have been in a natural channel. And if there are no wetlands to absorb the brunt of the flood, there is more erosion, more property damage, more loss of life.

A movie short

Below is a five-minute video by Kael Alford called Bottom of 'da Boot: Louisiana's Disappearing Coast:

Bottom of 'da Boot: Louisiana's Disappearing Coast from Kael Alford on Vimeo.

Related posts

Disappearing Louisiana, Part 1: Stumbling on History
Disappearing Louisiana, Part 2: Water Words
Disappearing Louisiana, Part 3: Paradise Faded: The Fight for Louisiana
Disappearing Louisiana, Part 4: Revetments, Rip-rap, and Other Exotica
Disappearing Louisiana, Part 5: The Control of Nature: Atchafalaya

The Disappearing of Louisiana, Part 1: Stumbling on History

My intermittent series on "the disappearing of Louisiana" is about the effects of nature and man on Louisiana's land and waters. One source says that Louisiana loses 25 to 35 square miles of land a year, nearly a football field every hour. Where does the land go? It is sinking under water.  

I didn't know about the disappearing of Louisiana when I took my road trip here in the winter of 2011/2012. But by chance, I drove right through a mammoth, manmade complex designed to control the Mississippi River. And it plays a role in the land's disappearance.        

Below is an excerpt from a January 2012 post, when I stumbled on history: the Old River Control Complex:

Highway 15, Louisiana

I found myself driving along a levee, moving from Hwy 1 to Hwy 15. It's a damned good thing I gassed up in Morganza before I got onto 15. It was a l-o-n-g way between gas stations.  I drove aside a levee and a series of locks, dams and hydroelectric projects (or something) the entire way. The Old River Control Complex. Some interesting sites about same, most with cool pictures: 

Credit: USACE per Urban Decay

Credit: USACE

America's Achilles' heel: the Mississippi River's Old River Control Structure

Morganza Spillway/Floodway and Old River Control Structure

Where Does the Water Go? The Old River Control Structures, Louisiana 

I saw large white birds with black-tipped wings taking in the waters at the auxiliary structure. High fencing, barbed wire, big padlocks, and what looked like a thick electric-shock cable prevented me from getting a closer look. But I was able to use the office lavatory. Someone had written a sign inside the ladies' room: "If you can't clean up after yourself, then use the woods." Reminds me of a motel room in Memphis, Missouri, that had this sign in every bathroom: "Don't clean game in the sink."

Anyhoo, after an in-car lunch of hard-boiled eggs and a satsuma orange, I proceeded along my way.
  

I've got a lot of studying to do. 




Related posts

Disappearing Louisiana, Part 1: Stumbling on History
Disappearing Louisiana, Part 2: Water Words
Disappearing Louisiana, Part 3: Paradise Faded: The Fight for Louisiana
Disappearing Louisiana, Part 4: Revetments, Rip-rap, and Other Exotica
Disappearing Louisiana, Part 5: The Control of Nature: Atchafalaya