News Analysis by Kip Hansen
Jean Lafitte, Louisiana, is situated at two feet above sea level and about ten miles south of New Orleans. It has the misfortune to sit just outside of the protective system dykes and levees that keep New Orleans from flooding.
John Schwartz, at the New York Times, writes about “the ecological crisis facing Louisiana’s vanishing coast” in “Left to Louisiana’s Tides, a Village Fights for Time”, a long narrative magazine piece relating the struggles of this small town to save itself from what appears to be the ultimate fate of much of the Mississippi Delta:
“Saltwater intrusion, the result of subsidence, sea-level rise and erosion, has killed off the live oaks and bald cypress. Stands of roseau cane and native grasses have been reduced to brown pulp by feral hogs, orange-fanged nutria and a voracious aphid-like invader from Asia. A relentless succession of hurricanes and tropical storms — three last season alone — has accelerated the decay. In all, more than 2,000 square miles, an expanse larger than the state of Delaware, have disappeared since 1932.”
“….Just two miles north is the jagged tip of a fortress-like levee, a primary line of defense for greater New Orleans, whose skyline looms in the distance. Everything south of that 14-foot wall of demarcation, including the gritty little town of Jean Lafitte, has effectively been left to the tides.”
The Times’ piece lays out the emotionally rending story of this small bayou fishing village’s political attempts to somehow, anyhow, get itself included inside that 14-foot tall fortress-like system of levees that protect New Orleans from the rise and fall of the tides, storm surges and seasonal floods that relentlessly eat away at the coasts along the Gulf of Mexico.
Schwartz asks:
“Jean Lafitte may be just a pinprick on the map, but it is also a harbinger of an uncertain future. As climate change contributes to rising sea levels, threatening to submerge land from Miami to Bangladesh, the question for Lafitte, as for many coastal areas across the globe, is less whether it will succumb than when — and to what degree scarce public resources should be invested in artificially extending its life.”
Isn’t it a shame, what the river has done to this poor crackers’ land?
What has happened here? Where has all that land gone, and why? According to the US Geological Survey:
“The swamps and marshes of coastal Louisiana are among the Nation’s most fragile and valuable wetlands, vital not only to recreational and agricultural interests but also the State’s more than $1 billion per year seafood industry. The staggering annual losses of wetlands in Louisiana are caused by human activity as well as natural processes. U.S. Geological Survey scientists are conducting important studies that are helping planners to understand the life cycle of wetlands by detailing the geologic processes that shape them and the coast, and by providing geologic input to models for mitigation strategies.” – S. Jeffress Williams, U.S. Geological Survey
What are these forces that are causing the demise of the Mississippi Delta?
“USGS and other studies indicate that major shifts in the course of the Mississippi River have contributed significantly to the demise of the wetlands.
“The 300 kilometer-wide Mississippi River delta plain and its associated wetlands and barrier shorelines are the product of the continuous accumulation of sediments deposited by the river and its distributaries during the past 7,000 years. Regular shifts in the river’s course have resulted in four ancestral and two active delta lobes, which accumulated as overlapping, stacked sequences of unconsolidated sands and muds. As each delta lobe was abandoned by the river, its main source of sediment, the deltas experienced erosion and degradation due to compaction of loose sediment, rise in relative sea level, and catastrophic storms. Marine coastal processes eroded and reworked the seaward margins of the deltas forming sandy headlands and barrier beaches. As erosion and degradation continued, segmented low-relief barrier islands formed and eventually were separated from the mainland by shallow bays and lagoons.” — Louisiana Coastal Wetlands: A Resource At Risk
There is a nicely done, if simplistic, animation that illustrates some of the problems with the Delta at interactive-earth.com: How Have We Changed the Delta? (requires Flash). Here’s a few stills from the animation so we can see the situation today:
In words, from the American Museum of Natural History in NY City,
“Disappearing Delta: Humans have upset the delicate balance of land gain and loss in the Mississippi River Delta. Dams, levees and channels along the Mississippi have prevented land-forming sediments from reaching the delta, and most of those that do are discharged deep into the Gulf of Mexico. Meanwhile, old land continues to compact and erode, a process aggravated by human activity. As a result, over the past 75 years, almost 5,200 square kilometers (2,000 square miles) of wetlands, which once sheltered coastal cities from storms, have been lost to the ocean.”
Here’s the long-term historical perspective on the Mississippi Delta:
Today’s delta comprises the darkest black portions of the image. The graphic is organized from the smallest area to the largest, dark to light. The Delta has grown and shrunk over the last 6,000 years — and appears to have been at its historical largest limit about 3,000 years ago. Change in the Delta seems to be the constant, the rule, and not the exception.
The Times’ article draws parallels between the Mississippi Delta and both Miami and Bangladesh. Long-time readers here know the story with Miami, it is a disaster-in-waiting, and Bangladesh is the delta of a major Asian river system, diked and bermed and no longer being renewed, continually sinking below the level of the sea and rivers.
The Times’ Schwartz comes on strong about Sea Level Rise:
“…the master plan’s authors adopted far more pessimistic forecasts of the impact of climate change. They effectively doubled their previous 50-year projections for likely sea level rise to more than two feet, the highest rate in the country, according to the National Oceanic and Atmospheric Administration.”
The link goes to NOAAs Sea Level Trends map, which shows two nearby tide gauges that show a trend of around 9 mm/yr (3 ft/century) of ….. relative sea level rise. Yes, that it perfectly correct, USGS also blames many of the Delta’s problems on changes in relative sea level rise.
Reminder: “The mean sea level (MSL) trends measured by tide gauges that are presented on this web site are local relative MSL trends as opposed to the global sea level trend. Tide gauge measurements are made with respect to a local fixed reference level on land; therefore, if there is some long-term vertical land motion occurring at that location, the relative MSL trend measured there is a combination of the global sea level rate and the local vertical land motion.”
Relative sea level is the only sea level of concern to local residents and planning officials — it is where the sea meets the land at that spot. Local relative sea level rise (or fall) is the surface of the sea getting higher (or lower) in relation to the land.
Yet the Times’ Schwartz keeps referring to sea level rise caused by climate change. It fascinates me that Schwartz is allowed (or forced) by his editors to keep going on about climate-change-caused sea level rise yet somehow he actually never makes the distinction between changes in local sea level caused by subsidence and compaction of the land — the land sinking — and the type of sea level that can be caused by climate change — Absolute Sea Level and its rise or fall. Schwartz does not quantify Absolute Sea Level rise at all.
So what’s the real deal here in the Mississippi Delta? The USGS and NOAA both tell us the land is sinking — this is subsidence caused by the pumping of petroleum (and water) out from under the Delta and compaction of the sediments that make up the land.
In order to understand how much the surface of the Gulf of Mexico is rising, we have to have two things: a reliable measurement of the relative change between some point of land and the surface of the Gulf, which we can get from a good Tide Gauge, and a reliable measure of how much the land at that same point is moving up or down. The nearest Continuously Operating GPS Reference Station at a Tide Gauge (CORS) is at nearby Dauphin Island:
C. Letetrel et al. (2015) — “Estimation of vertical land movement rates along the coasts of the Gulf of Mexico over the past decades” gives us the two figures from “13 years of data from January 1995 to December 2010.” At Dauphin Island, the relative sea level is rising about 3 mm/yr. The land, however, is sinking at a rate of 4.2 mm/yr. The result for rate of Absolute Sea Level Rise is minus 1.26 mm/yr — at Dauphin Island, the surface of the Gulf of Mexico is not rising at all, it is falling. Now, if you’ve been following my series here, Sea Level: Rise and Fall, or Dr. Curry’s series at Climate Etc., you are well aware of the fact the sea level doesn’t rise evenly everywhere — so we can’t assume that the surface of the Gulf is falling at all points along the Gulf Coast. The same paper supplies a usable answer:
“We corrected the tide gauge records from the vertical land rates and estimated the absolute sea level rise [averaged along the US Gulf Coast] to be of about 2.07 (± 0.4) mm/yr. This value is comparable to the global absolute sea level rise estimates over the last 50 years (Church and White,2011): 1.970.4 mm/yr over the period 1961–2009.”
That makes about 100 mm over the 50 year period, or about 4 inches (or about 8 inches per century). There is nothing unusual about Absolute Sea Level Rise in the Gulf of Mexico — and at the Delta, the surface of the Gulf may even be falling — not rising at all.
So there may be a small contribution of the rising sea to the problems of the Delta but this is comparatively tiny when weighed against the effects of subsidence, compaction and erosion all compounded by the total lack of soil replenishment.
What has happened down here?
Man is losing yet another battle against Nature. The Mississippi River carries water from 1,245,000 square miles (3,220,000 km²) of its watershed which extends all the way up into parts of Canada in the northwest and southern NY State in the northeast.
This river system has experienced tremendous flooding — the Great Flood of 1927 being the most recent mega-flood. It was that flood that prompted a massive engineering project:
“Following the Great Flood of 1927, the US Army Corps of Engineers was charged with taming the Mississippi River. Under the Flood Control Act of 1928, the world’s longest system of levees was built. Floodways that diverted excessive flow from the Mississippi River were constructed. While the levees prevented some flooding, scientists have found that they changed the flow of the Mississippi River, with the unintended consequence of increasing flooding in succeeding decades. Channeling of waters has reduced the absorption of seasonal rains by the floodplains, increasing the speed of the current and preventing the deposit of new soils along the way.” – Wiki
That project, initiated 90 years ago, is the cause of the little village of Jean Lafitte’s problems today. The Great Mississippi is literally washing Jean Lafitte away — the river’s replenishing soil loads are being washed far out into the Gulf instead of being captured by the vegetation of the Delta. The barrier islands that in the past have been replenished each flood season have diminished and been washed away by Gulf storms — a reiterative process of erosion, death of the swamp and marsh, and more erosion as storms keep coming. After Hurricane Katrina, the Delta got a ten year streak of good luck and a chance to recuperate, but the 2017 hurricane season was harsh and extremely damaging.
The Mississippi Delta has further been damaged the dredging of canals to facilitate oil drilling and oil pipelines that crisscross the delta. Traffic on the canals causes boat wakes that eat away at the banks of the canals, widening them year after year. Almost everything that moves in the Delta moves on boats. The wider canals are subject to more wind chop which further erodes the banks, especially when storms come. We want the oil but it comes at a terrible cost for the Delta.
Is there a solution? Can Jean Lafitte and the Delta be ultimately saved? Should it be saved? If so, at what cost? These are questions that cross the lines between science, engineering and public values — and I have no suggestions to offer.
But one thing is certain — climate change, by any name, is not responsible for the fact that the Mississippi Delta is washing way.
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Author’s Comment Policy:
It takes a lot of time to dig up all the [alternative] facts to correct the skewed impressions that poor science writing in the media can create. Often, the task is to supply the rest of the story, or the details in which the devil lies.
The NY Times piece is part of a long series of stories on the human interest side of ecological and environmental disasters that insist placing the blame on “climate change” and specifically “climate-change-caused-sea-level-rise”. It appears so very easy to shift the blame for relative sea level rise to climate — which can only be responsible for absolute SLR. It is always possible that the journalists themselves actually don’t understand the point, I guess — but it stretches my imagination to think that someone could be hired as a science journalist without even basic science knowledge.
Randy Newman, one of America’s musical geniuses, wrote the song “Louisiana: 1927” — he performs it here. The incomparable Aaron Neville recorded the definitive version.
Address your comments to “Kip …” if you are talking to me, I’ll see it and try to answer best I can.
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How about having a time set to take the levees of the Mississippi River down, say in 50 years, and in the interim build high (both buildings and roads)?
Thereafter siltation is back.
Nearly 25 years ago I was a consultant to one of the earlier Mississippi River diversion projects, almost a half century ago I was on the committee that started the Louisiana Coastal Zone Management Program, and a lot in between. There is still mud in my pores and concern that so many still do not understand that “Land.-1a: The solid part of the surface of the earth” is a standard dictionary definition and a small portion of the delta. Most of the “wetland” loss is actually marsh conversion to shallow water to a meter plus or minus, even wetter. Two geologists remarked that the marsh is only a speed bump for storms, still better than open water. There is some land at Lafitte and closure of Bayou Lafourche at Donaldsonville was also part of the problem. It is also not “fragile” or “delicate” and is nothing like Miami, more like other deltas, which are all different. Neither are the people to have survived and prospered there.
Most of those writing about it, including too many scientists and journalists sitting behind computer screens, have little insight or experience with the problem. Long deceased old school geologists were convinced that the river could not be stopped from going down the Atchafalaya and they may be right as it almost went in 1973. It is the biggest and perhaps most misunderstood environmental problem in the United States, maybe North America. Little known, for example, some sediment is added in places from hurricanes and there is less coming down the river. There is also faulting and other natural processes. Some places with oil operations have little erosion. It is an amazing and very complicated place, but is, and will remain no matter what, one of the most productive places on earth. As noted, climate change is the least of their problems and the people deserve better analyses. They certainly did not get it with the oil spill.
I like this quote from geologists studying the Gulf as a largely closed system as the result of collection of “…organic and inorganic debris…” who stated crudely but accurately — “In terms of geologic pollution the Mississippi River was, and is, North America’s largest sewer system. It collects and dumps waste into the Gulf cesspool, where oil and gas forming processes start immediately.” (Clark, R. H. and J. T. Rouse. 1971. A closed system for generation and entrapment of hydrocarbons in Cenozoic deltas, Louisiana. Bulletin of the American Association of Petroleum Geologists. 55(8):1170-1178.)
There are no satisfactory answers, but there is a plan if anyone has brilliant ideas to compare.
http://coastal.la.gov/wp-content/uploads/2016/08/2017-MP-Book_2-page-spread_Combined_01.05.2017.pdf
HD ==> Ah, yes, the plan — of course, it was a plan that got them into this mess. Time will tell.
Kip: The Randy Newman version of the song is the definitive version. Neville is good, but not that good. Great article. Very informative.
Bob ==> Newman is a genius lyricist and composer — but not such a great voice (opinions vary). For myself, I almost always prefer the original singer-songwriter versions of everything, and live music over recorded/studio versions.
I maybe should have said, Neville version was the most popular of the covers and more recently famous.
Kip Hansen said:
Think about how dangerous they would be to the propaganda if they (the journalists) actually did have some science education; they wouldn’t do as well at supporting the desired pseudo-science as they do.
That wouldn’t sell as many papers.
sophocles ==> Yes, not so good for propaganda — but I think it has more to do with Editorial Narratives than sales.
Kip & others, [Hope this is late enough that it is not intrusive.]
If you have an interest in music history there is an interesting analogy to explore.
It is that of Steve Goodman and the song “City of New Orleans.”
“Riding on the City of New Orleans
Illinois Central Monday morning rail
Fifteen cars and fifteen restless riders
Three conductors and 25 sacks of mail…
Good morning America, how are you?
Say, don’t you know me? I’m your native son.”
– Steve Goodman, “City of New Orleans”, 1970
Steve had leukemia and also road the Illinois Central Railroad.
Realizing that such passenger trains and he were slowly dying, the song is an analogy one for the other.
It could just as well be for the Delta of which you write, but I’ve not found that such was in his mind 50 years ago.
Here he is:
Steve’s live version
He had to buy Arlo Guthrie a beer to get Arlo to listen to it.
I guess, as they say, the rest is history.
{Arlo changed a few words.}
Arlo’s City of New Orleans
John ==> City of New Orleans is in my personal (very limited) repertoire — which I play on my 1949 Martin 00-17.
The first time I heard the song on the radio — which I remember bright and clear — I thought they had discovered a new Woody Guthrie song not included on my Library of Congress multi-LP collection.
“Now, if you’ve been following my series here, Sea Level: Rise and Fall, or Dr. Curry’s series at Climate Etc., you are well aware of the fact the sea level doesn’t rise evenly everywhere — so we can’t assume that the surface of the Gulf is falling at all points along the Gulf Coast”
I haven’t been keeping up with the series, but this makes no sense to me that water rise/fall in a regional area like the Gulf of Mexico isn’t consistent, after filtering out influences like storm-surge river drainage, changes to salinity and temperature, etc. Assuming, of course, that there is no land rising/falling.
icisil ==> Well, that’s the actuality. See Is sea level the same all across the ocean?
Such deltas have come and gone through-out history , even major rivers can and have changed their course with significant effects down stream with no help from man .
Wait- if Man is such the problem, why aren’t they fighting to remove the levees and go back to nature???
Nothing will help the AGW “problem” like a Major city being washed into the Gulf (we’ll just ignore the pollution for now- no more CO2 from NO!)
John Schwartz is an idjit. Those areas are subsiding because of the channelization of the Mississippi. Nothing to do w/”sea-level rise”.
beng135 ==> Read Schwartz’s piece in the Times. You’ll see he talks of all the real causes and then concludes that because of future expected sea level rise caused by climate change things are desperate. He has conflated Relative Sea Level Rise (caused by subsidence and compaction) with Absolute Sea level Rise, which is negligible in the Gulf of Mexico.
Give them their share or river mud in place of NYT word count.
It’s not difficult. If you buy a house down there, know what you are doing. If you build a house down there, you might want to consider building it a couple of feet higher off the ground than your neighbors.
It is probably as true today as it was a century ago, except that today you have no excuse for ignorance. The people writing for the NYT are anyway probably too afraid to go anywhere near a place with the word Mississippi attached to it, in case they met a Trump supporter. So it shouldn’t trouble them unduly.
Kip, once again you have provided me with a starting platform to teach my science classes complete with references. You publish it a day after I introduced my Environmental Science class to the paddlefish, and now we have a starting point to discuss anthropogenic changes to riverine systems and those affects to the species adapted to them. Since we are in a school in Louisiana, we have the additional requirement to bring those topics to a more localized point of view, which you provide here. Thank you.
There are many programs you don’t mention specifically which are designed to both build awareness and actually do something constructive to marsh restoration. One of these is known as “Marsh Maneuvers”, a 4-H program which educated children in how marsh/wetland ecosystems function, the threats to them, and how restoration efforts are conducted. MM takes it a step further and provides these students with an opportunity to participate in the planting of wetland plants in areas where freshwater inputs have been restored and a brackish water environment is established. Particularly planting Spartina sp. is conducted in wetlands. This program has been in place for at least 20 years.
If you wish to educate yourselves (speaking more broadly than just Mr. Hansen) on wetland science, I recommend the text, “Wetlands” written by Mitch and Gosselink, used broadly in graduate level studies. My edition is getting outdated, but I believe there are more current versions. These guys are a little on the liberal side, but the basic science is sound and well founded.
PRDJ ==> Glad to have been of assistance.
My wife and I worked for years in the Caribbean doing various humanitarian projects — some of them related to reclamation of mangroves and the like.
Thanks for the reference to Wetlands.
Gosselink is a very good scientist, part of the long legacy from the realists dealing with the problem. Marsh (and other) restoration is sometimes a pork barrel project, too often fails. This is a good summary useful for students, possibly available on line.
Gosselink, J. G. 1984. The ecology of delta marshes of coastal Louisiana: a community profile. U. S. Fish Wildl. Serv. FWS/OBS-84/09:134.
While there is a younger group that seems to be more realistic, there are still otherwise good scientists bought into it. This work while having some good information is an example, and the chapter on Louisiana is inadequate. Day, J. W. Jr. (Ed.) 2013b. Gulf of Mexico, Origin, Waters, and Biota. Ecosystem-Based Management. Vol. 4. Texas A & M. Univ. Press.
Gulf of Mexico sea levels are a mess. Seasonal levels vary more than daily, and in the early 90s there was a long period when Louisiana marshes were never covered. Not considering possible cooling and even sea level falling, even as a mental exercise, is a scientific failure..
Kip, I agree with Germinio’s post above, and have have read your entire essay, which ends with,
“But one thing is certain — climate change, by any name, is not responsible for the fact that the Mississippi Delta is washing way.”
You are building a straw man. The Times article clearly comments on the natural part of the subsidence, and gives several column inches to the fact that one partial cause, petroleum extraction, has been known for half a century. The Times discusses the effects of levees in detail. The article is 9000 words long, and does mention climate change as contributing to the problem, but makes clear that climate change is not the main cause of the present problems.
Your calling the writer of a well written comment a “Troll” perhaps exposes your real intent.
Bruce ==> The NY Times’ Schwartz leads with this paragraph:
“Jean Lafitte may be just a pinprick on the map, but it is also a harbinger of an uncertain future. As climate change contributes to rising sea levels, threatening to submerge land from Miami to Bangladesh, the question for Lafitte, as for many coastal areas across the globe, is less whether it will succumb than when — and to what degree scarce public resources should be invested in artificially extending its life.”
That paragraph, in journalism, is called the “lede”
Bruce ==> continued . . . . The “lede”, in journalism, is defined as
Schwartz gives what he considers the most important aspects of his story in the “lede” — the opening sentence or paragraph. His lede, in this story, is about the threat to Jean Lafitte from sea level rise caused by climate change — what NOAA correctly calls Absolute Sea Level (and its rise or fall).
That is what his story is about. Only he failed to tell us about what the actual threat from global climate change-caused SLR, at all…..I have added that to the story for readers here.
Kip, Sorry I missed that mention, but that is a nit.
The operable quote would be, as you say, “…climate change contributes to rising sea levels.”
There are many who fancy themselves as “science journalists” but who don’t know beans about science. But then, what is “science”? The definition is changing.
Back when I was a science student at a state university, the profs and textbooks all had a unanimous definition of “science”. It was defined as a methodology, and a “scientist” was anyone who practiced that methodology. But even then there were “scientists” teaching at universities who claimed that certain beliefs, certain teachings, were “science” even though those beliefs could not be demonstrated using the scientific method.
Today it appears that the main definition of a “scientist” is one who has papers from a university saying that he is a scientist, that he works at a university or “scientific think tank” or something similar, and that he gets his ideas published in a “peer reviewed journal”. Once he gets his papers, he gets to define what is “science”. However, if he doesn’t go along with the consensus, he can lose his status as a “scientist”.
In short, when I studied at the university, it was the science that defined the scientist. Today, it’s the “scientist” who defines the “science”.
Now take the average journalist, who has never studied any science course other than maybe an introduction for non-science majors, whose main training has been on how to do interviews and report on them, among which is to focus on the human interest side of the story as well as the eye-catching “disaster”—how is he to deal with a “science” story? If not to interview “scientists” who make headline worthy statements? Is it any wonder that science reporting is so atrocious? How does this description not fit most “science journalists”?
Richard ==> This journalist, John Schwartz, studied law. His bio:
“John Schwartz is a science writer for The New York Times. He
writes primarily about space travel, and his work has taken him
from the Mojave Desert to Moscow. He has written on a wide
range of topics, including physician-assisted suicide, computer
security, online pornography, robots, and why pregnant women
don’t tip over. (It has something to do with an extra curve in their
spines.) Before coming to the Times, he worked for the
Washington Post, and before that, Newsweek Magazine.
John was born in Galveston, and attended UT. He graduated with
honors from the Plan II program, a fact that astonishes him to this
day, and also completed a major in Italian. He graduated from UT
law school and passed the bar, but has never practiced law. He
married his college sweetheart, Jeanne Mixon, who majored in
history. They have three children.”
I’m sure New Yorkers will gladly exchange Manhattan bedrock for Mississippi delta bedrock one for one since they don’t know the difference. /sarc
I am an owner of some of the wetlands that are disappearing in South Louisiana. The State has attempted to make a dynamic system static, succeeding in some ways, but failing miserably overall.
There are many causes of the degradation of the Louisiana’s wetlands but the most dominant causes are as follows:
• Louisiana has chosen commerce over conservation. Funneling the sediment and nutrient filled water of the Mississippi River onto the outer continental shelf to inexpensively maintain the river channel deprives the coastal marshes of needed sediment and nutrients. Coastal marshes are similar to cropland (managed forests included) in that they need an input of fresh water and nutrients to thrive. The levees along the Mississippi prevent this. (See also the Dead Zone in the Gulf)
• The bureaucracy, both state and federal have, since the 1970 have increased the costs to private landowners of doing anything to maintain their properties. Regulatory hurdles and Permitting costs often exceed the costs of the projects. And high cost projects are favored over low solutions as the bureaucrats seek security over solutions at every turn.
• The crisscrossing canals dredged for oil explorations in an abundant freshwater environment could be used as a conduit to channel freshwater to places of need. In a brackish or salt water system they channel vegetation killing salt water into now fragile marshes.
• Modern sport fishing boats have more power and less draft that ever before allowing the public to cause untold damage to formerly inaccessible areas. Prop washing by these vessels cuts root systems, destroys submerged aquatic vegetation and deepens channels increasing the salt water invasion.
Until Louisiana replenishes its marshes with sediment and fresh water the losses will continue
CVP ==> All very good points — especially the more powerful sports fishers going up shallow canals washing the banks away.
I feel that ATheoK and CVP have really nailed the situation.
I also feel that Stephen Skinner and MattS should apply the same logic of abandonment to Miami Beach, the New Jersey /New York shoreline and rivers, Charleston, Savannah, Galveston and especially Los Angeles, San Francisco, Portland and Seattle. Seems to me that years ago folks moved when things got tough, like the Okies did during the Dust Bowl, and others did years before. Mitigate or migrate or endure.
With that outta the way ( /rant), you will find those “dumb, backward” Coonass folks ( well understood term of endrearment down there, just ask) understand the problem, and they have moved and adapted and mitigated for years when they can’t fight Mother Nature or urban development or the Corps of Engineers anymore. They are not like the clueless folks in New York that experienced the “superstorm Sandy” when the water went up a few feet and the wind may not have reached 90 mph. Tidal surge? BEAM ME UP!!
THIS IS WHAT SURGE LOOKS LIKE!
Thousands of folks along the Gulf Coast from Galveston to Mobile took their lumps and moved or came back. Crazy? Prolly, but as long as the NWS provides great warnings and they have been there “before”, no big deal.
+++++++++++++++++
The channeling of Big Muddy has made delta restoration almost inpossible without some sacrifice by some folks south of New Orleans. There are a few diversion structures, but there are ecological and other considerations that many do not wish to endure – the commercial oyster and shellfish and sport fishing industries have adapted over the last 50 or 60 years to less brackish water than what existed when I was ten years old.
Storms do a bit of damage, but most of the wetland loss and subsidence has been to channeling the MIss and the many canals dug and exploited since the 1940’s. I can’t name any geologists that can make a case for subsidence due to taking out all the oil and gas from uner New Orleans or LaFitte.. And if so, then compare with the basic understanding and observations of delta formation and maintenance without flooding.
Coastal and wetland restoration in South Louisiana is not a straightforward endeavor. And the economic effects of abandoning the Mississippi from the Gulf to Nathez or Vicksburg would be immense to the nation and not the fishermen and folks growing sugarcane. I hope all that think those ports and refineries and such should be abandoned have many solar panels and windmills and furniture made outta wood.
Gums rants…
That is Holly/Dung Beach in La. correct?
Great comments CVP and Gums!
I forgot about the powerboat wave impacts. Though, I can clearly remember getting chided in Delacroix for going just a shade fast.
Kip:
The canals were cut for exploration and maintenance. Boats used by the riggers, supply and maintenance crews are not shallow draft for inshore vessels.
So, those canals are shallow when compared to the local Mississippi’s 200 ft depths and some of the deeper bayous.
Not lecturing but just stating. A river delta is created by a river depositing silt at the outlet into the sea. Deltas that are losing land (Mississippi, Nile Ganges-Brahmaputra) do so because the supply of silt has been disrupted or severely reduced. Sea level rise is incidental and ‘fixing’ that, even if we could, will not stop the current loss of land in all three deltas because if any delta is allowed to follow it’s nature the land would adjust upwards with new deposition if the sea level rises. Equally, if sea level dropped to what it was during that last or previous glacial maximums then surely a delta river would cut downwards through the silt as you can’t have a waterfall over silt?
“Is there a solution?”
Free the river. Let it loose from it’s man made chains and let it go back to replenishing the soils of the delta lands.
MattS ==> The next question then comes into play….At what cost? What towns and villages to be abandoned, what fisheries disrupted, oil fields abandoned, etc.
Somehow, my rant above did not align with some posts, but Kip Hansen has made the point. I do not wish to cut and paste the post.
Gums…
Eventually, in spite of man, the river will break free and carve a new path to the Gulf of Mexico.
What Kip asks is true, multiply.
Well, except for the oil fields and fisheries. Fisheries recover, oil fields don’t move.
That is, the Mississippi River changed course regularly. The Mississippi River will change course every time conditions allow. Each time leaving towns high and dry while flooding towns and localities in the path.
Perhaps worse, is finding oneself on the wrong side of a new river course.
I suppose the term “delta” (shape of the Nile one, I think) is meant to refer to land that can be seen above the water.
One of the USA’s big rivers, the Columbia, has amassed tremendous deposits of sediments — out from and well under the surface of the Pacific Ocean.
Next, search for ” North Cove, WA ” using Google Earth . This will take you to Washaway Beach, not named on the image, but you can search the internet for it. None know why North Cove is washing away.
Houses are cheap there.
Dynamic Earth. Fascinating.
Thanks again, Kip and all. Nice info here.
Here is a quote from the book “Louisiana a guide to the state. “ Compiled by the workers of the writers program of the work projects administration in the state of Louisiana.
This book was published in 1941. This is before global warming, before any offshore drilling, or drilling at all in the marsh with canals.
“In Louisiana, except for the alluvial deposits at the mouth of the Mississippi, The shore line is receding at the rate of 6 to 125 feet a year, irrespective of hurricanes, which can cause a retreat of several hundred feet in a few hours. Two factors cause this recession 😦 1) The regional tilting bought on by the weight of the growing Mississippi Delta, which causes the lands about it to dip more sharply and become submerged; (2) the ease with which the low-lying shore line is erodedi, as is shown by the greater depth of the recession on those portions of the shoreline which are more exposed to the prevailing winds and waves. Indeed, so noticeable and rapid has been the subsidence of the mainland, that many of the old plantations have become a region fit only for trapping,hunting and fishing. “
This is from page 19
Amazing what we have forgot
Paul ==> Thank you for that reference and quote.
Building and rebuilding a city on land that is sinking into a swamp is daft. Sounds just like a Monty Python comedy routine they did about 40 years ago. This is geology, nothing to do with man-made global warming.
I see:
“Building and rebuilding a city on land that is sinking into a swamp is daft. ”
PLZ explain that to the Dutch. And maybe lecture the New Jersey folks and Long Island folks and others in the northeast about building right on the water and then getting subsidized flood insurance to rebuild.
You are correct, Brad, about global warming and climate change not making things tough in south Louisiana, They do not apply and won’t.
OTOH we humans have done much in the last 100 years ago that nature might have taken hundreds of years or just one big flood to do. We also exacerbated things by building thousands of miles of canals and such to make things profitable for the petro industry and basic shipping. If the Miss stopped flowing today we could use the riverbed and get ships up to the Old River project and thence upriver to the rest of the United States. The Atchafalaya River could use some help for infrastructure, but it would offer good access to the Gulf and vice versa.
And while we wonder about New Orleans, what about the folks building on landfill in San Francisco and waiting for the “big one”. New Orleans will do just fine as those folks have more control about the effects of nature than the California folks living on active geologic faults.
Rant off…….
Gums sends…
“In the space of one hundred and seventy-six years the Lower Mississippi has shortened itself two hundred and forty-two miles. That is an average of a trifle over one mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oolitic Silurian Period, just a million years ago next November, the Lower Mississippi River was upwards of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing-rod. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo and New Orleans will have joined their streets together, and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.”
— Mark Twain, Life on the Mississippi (1883)