With the possible diversion of the Mississippi on the line, man’s effort to resist the diversion is becoming one of the greatest river engineering problems ever encountered. There is evidence that does indeed support the theory that the Mississippi river is being captured by the Atchafalaya River and the evidence is available and very bountiful.
The data on the deterioration and the loss of the capacity of the flow of the Mississippi below the old river and the increased capacity of the Atchafalaya river has been witnessed, collected and authenticated. New neotectonic activity indicates as well that the tendency toward the diversion of the Mississippi river into the Atchafalaya River is becoming ever more prominent and increasing daily which may cause problems down the Mississippi and also along the Atchafalaya as the increased water flow could cause flooding.
There has been a report put out that concludes that congress should, but only with the approval from the President of the greatest country in the world, the United States of America, establish an independent commission that is made up of the world’s best and foremost professionals to study the diversion of the Mississippi river into the Atchafalaya river and figure out what the problem is and why the Mississippi river is running into the Atchafalaya river.
This commission should be able to investigate the Corps current policies that are in regards to the problem and to investigate other means of addressing the problem such as possibly slowing the current nature of the Mississippi below the old river. This slowing of the current nature of the Mississippi could possibly be accomplished by diverting more sediment into the Atchafalaya and or increasing the efficiency of the lower Mississippi river below Old river and by minor straightening, thus increasing the slope of the river and slowing the flow.
Also, in addition to the corrective measures, the abandonment of the Old River control system and then possible changes to alternate river courses that could and should be investigated and pondered upon. This commission’s findings should not be allowed to be “lost” among the tons and tons of previously commissioned congressional reports and studies that congress seems to not care about.
The results of this study should weigh heavily, unlike many things the government doesn’t feel is important and should also weigh heavily on any future directions that the Corps of Engineers, the Mississippi river ommission and then the most importantly, the congress of the United States takes to change the fact that the Mississippi river is being somehow diverted into the Atchafalaya River. Over the course of the last 150 years, man has constantly sought to harness the power of the great and mighty rive r. the corps of engineers has built countless levees, constructed many cutoff points, provided lots of floodways, added reservoirs for water to collect in, and even went so far as to improve and stabilize the channel and all the banks of the Mississippi river to keep it where it should be.
All of these measures and precautions were undertaken for the sake of flood control and navigation. There is not any doubt that the corps of engineers has been successful, but only to a certain degree. The river has a long memory and it wants to be free and natural and break free of the shackles in which man has placed on it. All of the man-made additions placed in and along the river require lots of continuous maintenance and are of course only temporary.
There are many well informed members of the scientific community that believe that the Atchafalaya will not only capture the flow of the Mississippi river but also completely take it over and this fact is only a matter of time. The Atchafalaya is one of the main distributaries for the Mississippi river and the corps of engineers diverts almost 30 percent of the water flow in the Mississippi river down the Atchafalaya river through the old river control system.
The historical development of the lower Mississippi is going to be broken down into four periods consisting of several parts taken out over a period of time. This breakdown is basically the same as Major D. O. Elliott used in his examination of the river and the improvement he tried to do in 1932 on the lower Mississippi. The first of the four periods is in a category of pre-federal involvement. Next, the second period extends until the creation of the Mississippi river commission. The third one covers the entirety of the operation of the Mississippi river commission until the flood control act of 1928 was passed.
The fourth and final period will cover the river development until the present date. There is controversy over who was the first white man to discover and map the Mississippi river and who should take credit for it. Most historians claim that Hernando De Soto discovered the river, but when they found the “admiral’s map” which shows the Mississippi and land around it which was found at the royal library in Madrid, it shows to support the claim that the Mississippi was not discovered by De Soto but by Columbus instead.
In the year 1502 Columbus departed from Spain on his fourth voyage, which was the voyage that he landed at Santo Domingo and then continued on westward. The topic of flux and the sources of nutrients in the Mississippi-Atchafalaya river basin to the Gulf of Mexico is a large study. The current annual flux (in 1980-1996) from this basin was about 1. 6 million metric tons a year and on average, the total yield was 497kg/km^2/yr. It was about 61% nitrate, 37% dissolved and particulate organic N and about 2% ammonium.
The nitrate concentrations in the Mississippi River and some of its tributaries in the Midwest increased in between 2 to 5 fold in the past century. The nitrate flux from the Mississippi basin to the Gulf of Mexico averaged nearly one million metric tons a year since 1980 and is more than three times as large as it was thirty years ago. Most of the increase of nitrate flux in the Gulf of Mexico occurred between 1970 and 1983. Sine around 1980 the typical annual flux was very highly variable due to the variable amounts of precipitation and the increased annual nitrogen inputs to the basin.
Events such as the flood of 1993 nearly doubled the annual nitrate flux to the gulf of Mexico as a result of the leached nitrate from the soil-ground water systems in the Mississippi-Atchafalaya river basin. The high annual nitrate fluxes associated with all of the flood event can most defiantly be expected to occur in the future as flooding is very common in this area, considering that it is indeed a river basin and all the tributaries that flow into it swell during heavy rains. The emphasis on gradient advantages and causes of river avulsion and the insights from the late Holocene avustion history of the Mississippi river are misleading.
While the gradient advantages are very necessary for an avulsion to occur, the late Holocene avulsion of the Mississippi river in Louisiana suggests that some factors such as substrate composition and the floodplain channel distributions are more important. The cross valley to the down valley slope ratios of the Mississippi modern floodplain do indeed range from around 16 to 110 and are typically >30, while the slope ration is around 35 at the location of the old river also known as the Mississippi-Atchafalaya diversion.
All of the values of the Mississippi river floodplain slope are significantly larger than values of avulsion threshold calculated by numerical models. There are several examples of the Mississippi and red river avulsion by some channel reoccupation support ideas that the channel distributions and substrate compositions are primary influences on avulsion. The modern Atchafalaya River incises some buried Mississippi river channel belt sands and the abandoned channel belts and crevasse-splay complexes consist of sandy substrates that facilitate scour and the development of some channels that are capable of capturing the Mississippi river.
The abandoned channels provide conduits for the Mississippi river to flow that can efficiently develop into avulsive channels. The Mississippi river is on the list of the Worlds top 10 rivers that input freshwater and sediment into the coastal ocean. The Mississippi river and river basin contribute 90% of the freshwater loading to the Gulf of Mexico and it terminates amidst one of the United States’ most productive fishing regions and the location of the very largest zone of hypoxia in the western Atlantic Ocean.
The significant increases in river nutrient concentrations and loadings of nitrate and phosphorus and also decreases in silicate have occurred in this century, and have accelerated since 1950. But, the consequences of that is that major alterations have occurred in the probable nutrient imitation and overall stoichiometric nutrient balance in the adjacent continental shelf system. These days, streams and rivers are not always much affected by nutrient loading, but in most cases these nutrient-enriched waterways flow to the ocean.
This nutrient loading problem occurs throughout the world in places such as the Gulf of Mexico, the Baltic sea, the Adriatic sea, and also the Black sea. But now the problem lies far beyond being concerned about the nutrients being discharged. It lies in the concern that the regions that it is being discharged in. The movement through large watershed and over long distances and their effects on large areas of coastal water. There are some practices that could help limit hypoxia on the continental shelf in the north part of the Gulf of Mexico, which is a seasonally sever problem that has persisted for the past decade.
Between 1993 and 1999 the hypoxia zone ranged from 13000 to 20000km^2. The hypoxia is very wide spread, persistent and very severe during June, July, and August, although the extent and timing of it can vary, partly because of the amplitude and timing of flow and nutrient loading from the Mississippi river basin. Land loss and habitat change to the Mississippi river delta and plain are very noticeable. Systematic measurements and the comparisons of maps and black and white photographs show how much the area has changed.
Also, the use of infrared imagery taken at 5 year periods from 1890-1978 have also been used to document the land loss and habitat change on the Mississippi river delta plain. This data can be used to not only document the change in the past, but it can also be used to predict conditions of the Mississippi river in the future. All of these findings have great significance to fish and the wildlife resources around the river, and flood-protection planning, and also planning in land ownership.
The apparent causes of the high rates of land loss include trying to harness the Mississippi river by using levees and control structures like dams. Some additional factors include canal dredging and accelerated subsidence that is related to mineral extraction, which are associated with saltwater intrusion. Over the past 2 years there were 4 cruises that were conducted at varying levels of discharge in the Mississippi and the Atchafalaya rivers where there were grab samples that were collected from sand and mud dominated sediments.
There is a special method that was used to determine the sources of terrestrially derived organic carbon, and this process is called tetramethylammonium hydroxide thermochemolysis method. Most of the lignin-derived materials in muddy sediments appeared to be derived from non-woody grass-like sources which decays much quicker than logs or other woody materials that are typically found in sandy deposits. The great amounts of tiny sand-sized woody materials found in the sandy sediments are likely made from woody plant materials.
There was a stubborn man named Bienville that would not listen to his younger brother when he told him that the area he chose would be subject to flooding from the Mississippi river when it came a heavy rain, so thus New Orleans was founded. Then, to protect the city from all of the flooding, there was a levee system that was begun and then by 1727, there was 5400 feet of levee that was complete. This levee system extended all the way up and downstream of New Orleans with the property owner responsible owner for the construction on his part of the river.
The property owners were made responsible by and order from the French crown and if they didn’t comply they had to forfeit their lands for noncompliance. Then, by 1744 the levees extended from just past new Orleans by about 20 miles to the mouth of the Arkansas river on the left bank (looking upstream of course) and then all the way down to Baton Rouge on the right bank. There was a whole lot of work done in the New Orleans area during this time to stabilize the banks and then there was some crude dredging that was attempted at the river mouth in order to widen and deepen the channel to increase navigability and increase shipping.
In closing, in my opinion, the Atchafalaya river is not capturing the Mississippi river and there is nothing to be worried about. I do believe that there is a lot of flux and the nitrate levels do indeed increase during heavy rain and are still increasing. Building the city of New Orleans was a bad decision in the place where it is located right now. I believe that the Mississippi river will one day break its banks near New Orleans and will flood the city.
