Showing posts with label flood. Show all posts
Showing posts with label flood. Show all posts

Monday, October 10, 2022

Missouri: Linn: A Turtle and a Memory

I met a sibling for lunch in Linn, along Highway 50. 

Outside the restaurant, on the pavement, was a turtle. 

Turtle outside Mexican restaurant in Linn, Missouri. October 2022. Credit: Mzuriana.
Turtle outside Mexican restaurant in Linn, Missouri. October 2022. Credit: Mzuriana.

 

An odd location, it seemed. 

I bent down to take a look and to take a snap, and to whisper a hope that if it planned to cross the road that it would do so safely as it moved through the parking lot. 

Seeing the turtle reminded me of an upcoming anniversary: The Great Flood of 1993

That spring and early summer, before the flood came, it had rained and rained and rained and rained for weeks. There'd also been more than usual rain in the preceding fall. 

From the street's-eye view of that time, it wasn't the rain that caused note. It was the End-Times number of creatures that my descendant and I saw en route to Arrow Rock from Jefferson City, each day we went up for her rehearsals for the Arrow Rock's Lyceum production of Oliver. Snakes, turtles, frogs. Some living, some squashed. 

My parents' business was in the flood plain of the Great Flood. 

Here's an entry from my mother's flood journal: 

Saturday, July 31, 1993

The impossible happened - the levee that was built to withstand a 100-year flood ... broke. At 11:30 p.m. Friday night something awakened me - and my eyes focused on the television ... I could see a spotlight shining down on flickering water and hear the helicopter whirring sound and the announcer's voice telling of the levee break. 

In a very short period of time, hundreds of acres of what was Chesterfield's [Missouri] economic boom were under 10 to 14 feet of water in some places. Some 500 businesses were down - virtually all without flood insurance. Many of us had gotten it a day or two before - feeling the Tuesday crest just might spill a few feet over the levee. A five-day [waiting period in coverage] (after you pay the premium) is required before the insurance is effective so most of us will not have flood damage insurance money. 

All day we watched and listened; we saw a man chest high in the water plucked up into a basket lowered by helicopter, people rescued from rooftops of businesses .... 





Monday, February 3, 2014

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





Tuesday, January 21, 2014

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:






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