River Erosion- Week 3- Tim Pester

  

 River Erosion, featuring the Nile River.

In my virtual tour of a rivers around the world, I chose to pick the Nile River. The Nile river is one of the largest rivers in the world. As this massive river flows from the south of eastern Africa to the north, until it finally ends its 4,100-mile-long journey by emptying into the Mediterranean Sea (Boyer, 2015).  As this mighty river flows through the lands it is helping in the erosion, transportation, and depositing of sediment throughout the process. Whether that is the result of a strong river flow velocity because of higher water levels. These higher water levels also increase the energy of the moving water that helps to lift mineral or sediment particles from the bedrock and carries them down stream this process is also called hydraulic action (Lattanzio, 2000). An example of this process is when you are wading through a river, and you can feel the river bed moving slowly under your feet. During the process of hydraulic action, three different kinds of sediment loads are carried down the river. The first is dissolved load. In this load, the minerals or sediment that has been dissolved in the water is carried by the current. The water’s velocity flow has no barring on this type, and slow- or fast-moving water carries this load. The next type is suspending load. An example of suspending load is when a person jumps into a river and kicks up a bunch of mud into the water making it murky. This murkiness does not last long as the current of the river quicky sweeps the murkiness away and carries these particles downstream. The last type of hydraulic action is the bed load. In this process, the larger particles (Sand, Rocks, or Boulders) bounce, jump, roll or are push down stream. Depending the size of the particle in question, the water flow velocity might need to be very high (Tarback, 2016).

Another fascinating part of the Nile River is how it forms on its path to the Mediterranean Sea. If seen from the skies, it almost has a snake like appearance, as it curls almost in multiple “S-Shape” like bends. This development is better called meandering. While meandering causes the snake like appearance in the river, they also help with the erosion and depositing process. The outside of the river, or the back of the snake, the water flow is the strongest. In this higher velocity particles are continually kicked up and push down the river. Also, the banks of the river are eroded away causing cut banks to form. On the belly of the snake, or the inside of the river, the lower velocity of the water flows causing particles to be deposited creating point bars. Because meandering rivers, like the Nile, are constantly changing due to erosion and depositing of minerals, in the higher water volume times the chance of flooding can occur. While flooding can be devastating natural occurrence, it is also an important cycle for the surrounding area. In the process of a flood, the water volume over runs the rivers’ banks spilling into the landscape causing a flood plain. In a flood plain, the flood water carries with it a muddy, organic sediment that enriches the soil. This enriched soil is ideal for growing crops, like when the Ancient Egyptians relied on the Nile to flood, so they could farm the land. While the Egyptians called this process the annual flooding of the Nile, most science determine that natural rivers flood once every two years (Why Do Rivers Flood?, 2020). 

                               women and children on the banks of the Nile

The Nile River has been a central feature of life in northeast Africa for thousands of years. Even today, families come to gather water from the riverbank, surrounded by ruins left by ancient civilizations.

PHOTOGRAPH BY DAVID BOYER

Works Cited

Boyer, D. (2015). Nile River. Retrieved from NAtional Geographic: https://www.nationalgeographic.org/encyclopedia/nile-river/

Lattanzio, R., Beaty, S., & Annenberg/CPB Project. (2000). Earth revealed. Washington, DC: Annenberg Media.

Tarback, F. L. (2016). Essentials of Geology. New Jersey: Pearson Education.

Why Do Rivers Flood? (2020). Retrieved from American Rivers, Rivers Connect Us: https://www.americanrivers.org/rivers/discover-your-river/why-do-rivers-flood/#:~:text=Even%20though%20rivers%20can%20vary,approximately%20HALF%20of%20all%20years.