Describe and explain the changes that occur in a river channel as it moves from source to mouth.
All rivers have an upper, middle and lower course. The long profile of a river is basically the changes in gradient at these different stages in the river, every river is trying to achieve a smooth, concave, long profile.
The river begging in the upper course, normally in the hills and mountains. Here the river is smaller, the flow is fast and load and water volume are slow. The river erodes a v-shaped valley. At this stage the channel is inefficient as it has a large channel surface compared with channel surface area. There will be more friction as more water touches the river bed. A steep gradient is needed to maintain the rivers energy levels. The path of the river is fairly straight.
A river can erode the soil and rocks which form its channel banks. They erode in four ways Abrasion, Corrosion, Attrition and Hydraulic action. The main erosion processes that take place in the upper reaches are:
Abrasion or corrasion-This is when rocks in the sediment load which is being carried along by the river hit the rock materials on the bed and banks of the river. This is most effective if the river is flowing at high velocities like the upper course. This is the main process that causes vertical erosion.
Hydraulic action- This is the force of moving water. Loose sediment is most susceptible to hydraulic action. This happens at high velocities.
Corrosion-This is the chemical weathering of minerals in rocks in contact with the river water. The minerals in the rocks are slowly dissolved, eventually causes them to break apart. This process is most effective where there is fast flowing water and the river is not already saturated with minerals again this will therefore be more effective in the upper course.
Attrition-this is the process where the rocks in the sediment load erode by colliding with each other as they are carried along the river. The result is that the sediment load becomes more rounded and smaller in size. Even though this process takes place in the upper course the sediment tends to be larger and more angular here as attrition has not been acting on them for very long, however Sediment can be added anywhere along the rivers course.
An increase in pebble roundness in the direction of long shore drift. The process of attrition will erode the pebbles. c) A decrease of pebble size in the direction of long shore drift, again attrition is involved. d) Undercutting (active erosion of the cliffs at one end of the bay).
Barry opens by contrasting the views of other credible intellectuals in stating his fascination with the mechanics of the river. His initial two paragraphs fail to identify the Mississippi River itself, but hint at the rivers magnificence by mentioning its “turbulent effects” and “river hydraulics.” Barry continues to awe his audience with extensive discussion of all its velocities
Sedimentary rock from the older Silurian Period is further from the river banks (Geological map of Victoria, 1973). Mudstone, inter-bedded shale and greywacke depositions indicate the Maribyrnong River may have previously taken a different shape, and younger sediments have replaced the older sediments in more recent geological periods.
A major flood on any river is both a long-term and a short-term event, particularly any river basin where human influence has exerted "control" over the ri...
Hydrosphere of the Mississippi River A Case Study of * River management * People interfering in the hydrosphere * A flood management scheme River Basin / Catchment area The source of the river is the eastern side of the Rocky Mountains and the Appalachian Mountains to the north. There are many hundreds of tributaries including the Red River, Missouri river and the river Ohio. The mountains form the river's watershed. From Minneapolis the river flows South-East into Iowa where it flows south as far as Davenport. At Davenport it is joined by more small tributaries.
In truth, the river is the border between the gothic space, the Other, and normal space in the novella. For example, in the beginning of the story, when Danillo and Katherine were travelling home on the Dnieper, they witnessed a rising on the side of the Other. “A withered corpse rose slowly from it [one of the graves in a graveyard]. one could see he was suffering terrible agonies” as he begged for air (Gogol 18). Things that should not happen, that should not be possible, happen on the other side of the Dneiper because that is the gothic space.
and the action of the St John River, slack water in the Habour occurs at
The history of the Chicago River is an interesting part of Chicago. The Chicago River was shallow and stagnant, but it had much potential because of its location and what it provided to the city. The Chicago River altered the human population as Chicago developed into a big city. Because of the river factories and stock yards moved in and caused major problems for the city. The rise of Chicago's Stock Yards was a significant benefactor to the city's pollution problem. In the late1840s Chicago large stockyards moved into the city along the river and dumped all of the meat packing waste into the river. Because of this problems such as, sewage, factory waste, and other wastes over flowed the river, and badly polluted the river. Unfortunately the river was connected to Lake Michigan, the source of water for Chicago residents, drinking wate...
When it floods sediments can affect the land by losing nutrients in the soil and it can also affect the clarity of
Removing vegetation removes the root systems, which help hold soil in place. Running water can now more easily wash soil and rock away, increasing erosion.
...ansportation in the natural direction of the littoral drift. This particular jetty is responsible for the accretion of sediment immediately adjacent to the South Jetty (Kraus).
It is important to look at the geography of the Yellow River as well as the characteristics. The Yellow River is given its name due to the vast quantities of soil that are suspended in the water which turn the
Changing the course of the Alpheus and Peneus rivers so that they would flow through the stables
which can be used as a river, and also attracts people as it can be
If the gradient is steep (like the example on the right) then this can indicate that the amount of rainfall becoming overland flow is very high, the result of this is that all the water reaches the river very quickly and all in a short period of time, this gives the immediate steep ascending limb on the hydrograph. Reasons for large amounts of rainfall becoming overland flow can be little vegetation and maybe impermeable rock below the surface. Being impermeable rock, the water cannot infiltrate through this and become ground water, instead it flows over the ground to the river. Urban development and agricultural practices contribute to overland flow.