The control of nature readings : Atchafalaya
The readings focus on the Atchafalaya, which initially was a tributary of the Mississippi. It was one of the rivers used for transportation in the US, and this is underscored by the readings when they mention boats being used to transport goods and people across the tributary. The readings highlight that the Atchafalaya had undergone headward erosion, and after several decades, it managed to draw off water from the Mississippi (Aulenbach et al, 2007). It is argued that its volume in the 1940s was approaching one-third. As a result of erosion, the Atchafalaya widened and deepened, drawing more water from the Mississippi. After several years, the Atchafalaya had shifted from being a tributary of the Mississippi to a master stream. Essentially, the readings underscore the fact that the Atchafalaya was an offspring of the Mississippi, which was gradually decreasing in volume after directing a large volume of its water to the Atchafalaya. The fact that the Atchafalaya drew water from the Mississippi had various consequences, which included the destruction of New Orleans and the demise of Baton Rouge. Apart from the Mississippi, the readings postulate that the Atchafalaya also captured the Red River, which previously was also a tributary of the Mississippi. As a result of the capture of the Red River, the Atchafalaya’s power was increased, and this played an integral role in its eventual capture of the Mississippi several decades later. One condition for river capture is that the parent river must be at a higher level than the capturing river, and this fact is underscored by the readings that state that the water on the Mississippi side was eighteen feet above sea level whereas the water on the Atchafalaya side was only five feet above sea level. The readings mention that the Atchafalaya is widely described as one of the most treacherous in the world despite its quietness and smoothness. The readings go ahead to mention that the more water the Atchafalaya takes, the bigger it gets and vice versa. The fact that the Atchafalaya continues to get more water has resulted in flooding, which has prompted responses from the relevant authorities. In an effort to control flooding in the region, control structures were erected along the river, and this kept away floods for several years.
The readings from an engineering point of view
The readings mention that the construction around the Old River with the aim of controlling floods was carried out by engineers. An interesting engineering aspect that can be identified in the readings is that in the construction to control floods, concrete was penetrated by exploratory diamond drills. The readings also mention that a road was built over the structure, with more holes drilled on it, and the holes had diameters of the size of dinner plates, and grout was inserted expertly in the below cavities, and thus resembled fillings in a row of molars. Without a doubt, there is an engineering knowledge applied in the construction of the area around the Old River with an objective of controlling floods, which are experienced due to the large volumes of water contained in the Atchafalaya. To continue with the construction, diversion of Mississippi River flow was essential (Allison et al, 2000). The readings also state that rock riprap and cement grout, were used in the performance of emergency foundation repair that was to safeguard the erected structure from potential total failure.
Allison, M. A., Kineke, G. C., Gordon, E. S., & Goñi, M. A. (2000). Development and reworking of a seasonal flood deposit on the inner continental shelf off the Atchafalaya River. Continental Shelf Research, 20(16), 2267-2294.
Aulenbach, B. T., Buxton, H. T., Battaglin, W. A., & Coupe, R. H. (2007). Streamflow and nutrient fluxes of the Mississippi-Atchafalaya River basin and subbasins for the period of record through 2005 (No. 2007-1080).