1. John McPhee’s book?The Mississippi River, with its sand and silt, has created
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1. John McPhee’s book?The Mississippi River, with its sand and silt, has created most of Louisiana, and it could not ave done so by remaining in one channel. If it had, southern Louisiana would be a long narrow peninsula reaching into he Gulf of Mexico. Southern Louisiana exists in its present form because the Mississippi River has jumped here and there within an arc about two hundred miles wide, like a pianist playing with one hand—frequently and radically changing course, surging over the left or the right bank to go off in utterly new directions. Always it is the river’s purpose to get to the Gulf by the shortest and steepest gradient. As the mouth advances southward and the river lengthens, the gradient declines, the current slows, and sediment builds up the bed. Eventually, it builds up so much that the river spills to one side. Major shifts of that nature have tended to occur roughly once a millennium. The Mississippi’s main channel of three thousand years ago is now the quiet water of Bayou Teche, which mimics the shape of the Mississippi. Along Bayou Teche, on the high ground of ancient natural levees, are Jeanerette, Breaux Bridge, Broussard, Olivier—arcuate strings of Cajun towns. Eight hundred years before the birth of Christ, the channel was captured from the east. It shifted abruptly and flowed in that direction for about a thousand years. In the second century A.D., it was captured again, and taken south, by the now unprepossessing Bayou Lafourche, which, by the year 1000, was losing its hegemony to the river’s present course, through the region that would be known as Plaquemines. By the nineteen-fifties, the Mississippi River had advanced so far past New Orleans and out into the Gulf that it was about to shift again, and its offspring Atchafalaya was ready to receive it. By the route of the Atchafalaya, the distance across the delta plain was a hundred and forty-five miles—well under half the length of the route of the master stream.
2.River has had 7 distinct deltas in 5000 years
Caused by severe flood events wen the river broke over natural levees and changed course
The weight and compaction of the sediment causes adjustments in Earth’s crust
This is why Louisiana is subsiding
Puts more stress on the natural and artificial levees
Oil and gas extraction may also have an effect
What is the relationship between these two paragraphs?
? ??????? The Control of Nature by John McPhee discusses 3 detailed case studies of humans battling against nature. Your task for this project is to discuss how each of these case studies relate to specific terms/definitions and concepts that you've learned about in the Physical Geography class this semester. Read the instructions and guidelines for each part of the assignment carefully: Part 3: Los Angeles Against the Mountains (10 points) This section of the book best relates to the chapters on Weathering, Karst Landscapes, and Mass Movement and Tectonics, Earthquakes, and Volcanism. Review the main textbook chapters on these topics as well as the Powerpoint presentations. Also feel free to review your question assignment on this part of the book. Select 3 terms/definitions or concepts from the chapter or Powerpoint and write a paragraph about how this section of the book relates to those 3 terms. Be as specific as possible when selecting terms/definitions. If you used a term for another part of the paper, you cannot use it again. Before each paragraph, type a direct quotation from the John McPhee book that relates to one of the terms and you're writing about (include the page number after the quote). Your paragraph should be at least 200 words (the quotation doesn't count toward the word count).Explanation / Answer
The water flowing into river naturally deposits sediments along the side of its movement creating a natural levee, the banks of the rivers are slightly elevated from the river bed, this banks form natural levee and are composed of sediment, silt or by the material deposited by the naturally flowing water, they are often parallel with the flowing river, hence they can direct the flow of the river water.
Whereas the Artificial levees are usually constructed by pilling soil, sand, or rocks on the level surface, places where the river is flow is very high artificial levees are being constructed using wood, plastic or metal and concrete in order to protect the land loss by the moving water.
Extraction of subsurface resources such as groundwater, oil and natural gas in coastal areas may accelerate the rate of subsidence, its a natural process in which land surface is lover down and it occurs naturally as the soft sediments gets compacted, but due to the human indulgence this may have been accelerated, in the past 200-300 year human intervention is causing an imbalance in sediment deposition and subsidence resulting in large-scale erosion along the Mississippi river delta. It’s estimated the rate of subsidence along the deltaic plane is at about 4-4.6 feet per century and 1.3-2 feet per century along the plains.
The rate of destruction has been increased with the advancement of human indulgence with the natural process it needed to be rectified otherwise in the coming days we need to prepare for losing Louisiana as most of this area is in the continuous influence of flooding event.
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