Essay PreviewMore ↓
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.
How to Cite this Page
"River Channel Changes." 123HelpMe.com. 17 Jan 2020
Need Writing Help?
Get feedback on grammar, clarity, concision and logic instantly.Check your paper »
- Exploring the Channel Characteristics of the River Chess The aim of this investigation is to explore the channel characteristics of the River Chess. My main interest involve in understanding Hydrology, and how the river changes as it goes downstream. To obtain my results I visited a field centre in Amersham, were we were put into groups and were guided by a member of the FSC centre.... [tags: Papers]
789 words (2.3 pages)
- A Study of the Changes in River Processes This is a study of the changes in river processes along the long profile of a river. To study this we will use a sample river. The river the study will be based on Loughton Brook, which is a river situated in Epping Forest in Essex and is also a tributary of the river Thames. A journey will be made to the river and measurements will be made at three different sites. The measurements that were taken will be studied so conclusions can be made about the changes to characteristics of a river with distance downstream.... [tags: Papers]
4006 words (11.4 pages)
- The Downstream Changes of Pollution in the River Cray Introduction ============ The source of the River Cray begins in Priory Gardens in Orpington through Sidcup and into Crayford and then finally into the River Darent near the Dartford Marshes. The route of the river takes it through many urban areas which will most certainly add pollution to the water. The river is a low lying river and is also a first order stream. Aim === To investigate the downstream changes of pollution in the river Cray.... [tags: Papers]
1440 words (4.1 pages)
- Do my promises for over 30 years ago, that I made for the Tumaga River; we’re still remains the blood and life of my fellow Zamboangenos. Does that wishing stone that I threw, in the late afternoon, at the middle of the river, answer to what I promise before. In the hope, I want to see, that this river will always remain as what I have seen it when I was 6 years old. These are few of my countless childhood promises that I have made. A promise, that it still reminisce me every time I see this death river that was once a lively, a colorful and a happy river in the past.... [tags: Mithre J Sandrasagra, Drinking Water]
1307 words (3.7 pages)
- The Physical Characteristics of a River Introduction: River Features are elements of the landscape produced by fluvial processes-that is, the action of running water as it flows through the channels forming the drainage network of a river basin, eroding, transporting, and depositing sediment. (Source from Microsoft Encarta Encyclopedia 2001) A useful way to study a river is to look at its long profile and its cross sectional profile. The long profile of a river is a section drawn along the length of a river from its source to its mouth.... [tags: Papers]
1992 words (5.7 pages)
- Using the results gathered from a recent field study at the The Leigh Brook, suggest the morphological, hydrological and sediment differences between the Pool and Riffle. Within a river there are areas known as pools and riffles. The pool is an area of deeper slow moving water, whereas the river is an area of shallow, fast flowing white water. The rocks are also clearly visible at the riffle, but submerged in the pool. A pool is usually found on a meander whereas the riffle is normally seen on the straighter areas of the channel, they tend to be situated very close to one another, forming in sequences.... [tags: water motion, the leigh brook]
1322 words (3.8 pages)
- Leadership in Aberdeen and Green River I have researched Aberdeen's and Green River's leadership and communication processes. I will explain if work group and teams will work at Green River. Then I will describe the differences in leadership at both facilities along with an explanation of how to implement the changes at Green River that are needed to match Aberdeen's leadership skills. Following that I will describe the differences in communication processes at both facilities along with an explanation if the unique communication adopted by Aberdeen can effectively be used in Green River.... [tags: Business Compare Contrast Management]
1116 words (3.2 pages)
- Investigation of River Gwaun Introduction I am investigating how the course of the river changes from the source to the mouth. I will study the River Gwaun at 4 sites, starting at Gellifawr (near the source), then going to Pontfaen, then Llanychaer, then finally ending at Lower Fishguard, near the mouth where the river meets the Irish Sea. I went to do my fieldwork on the 20th May 2002 with my Geography class and another from my year. I was in a group of 5, with Richard Gledhíll, Chrís Strzeleckí, Jason Inglesant.... [tags: Papers]
3887 words (11.1 pages)
- Summary: The aim of this report is to analyse the river flow data from the River Severn in 2000 and 2001. The data readings will be taken from the Bewdley station 54001 over the 10 months of each year. The data will be analysed in graphical and statistical format in order to view trends and relationships easier. The results will be displayed as data i.e. either table format of raw data, from this graphs will be constructed to illustrate the various types of data and the way it will be displayed Contents: 1.... [tags: Statistics Data analysis ]
1420 words (4.1 pages)
- The Atchafalaya is the most original basins because it has a growing system with very stable wetlands. It is also the biggest river swamp in North America but has lost about 3,760 acres between 1932 and 1990. The loss of the wetlands is primarily due to erosion, human activities, and natural conversion. Many human activities, such as oil and gas pipelines, have interrupted the movement of flow and sediment within the wetlands that it is another factor in the loss of acres for the Atchafalaya.... [tags: essays research papers]
673 words (1.9 pages)
The main landforms formed in the upper course are.
Waterfalls, they are formed when a river crosses a layer of harder rock. This layer is eroded more slowly than the softer rock beneath it. Eventually a step in the profile of the river is formed with a plunge pool formed in the softer rock. As the layer of hard rock is undermined it will collapse and so the waterfall moves upstream.
This forms a gorge, a narrow valley with steep sides.
Transportation/deposition in the upper course. High velocities result in sediment being transported in the river, larger, heavier sediments can be transported due to the high velocity. Silt and clay also need high velocities to be transported as they are cohesive (stick together). Due to the high velocity there is little deposition.
In the middle course the angle that the river flows down is less steep, the volume increases when tributaries join the river and the load increases as the river has had time to erode. The velocity is slower.
The river becomes more efficient at this stage as less water is touching the river bed, reducing friction. The river starts to become wider and deeper.
The river now erodes laterally. The main erosion processes happening here are
Abrasion or corrosion (definition in upper course) as this is effective in high flow.
Attrition this process will still be happening, the sediments will now be smaller and more rounded as attrition has been happening for longer.
The main landforms formed in the middle course are meanders.
- The river is starting to meander. Erosion is greater on the outside of the bend, deposition more on the inside.
- Large meanders have formed
- The river cuts through the meander, leaving a straighter section and an ox-bow lake.
Transportation/deposition in the middle course, low velocities result in sediment being deposited, larger course particles are deposited rapidly as the velocity falls. Even when the velocity falls, fine particles, once set in motion can still be transported. Sediment transported under lower-flow velocities, as bed load, may become suspended load under high velocities.
In the lower course, the river slows down as the gradient is almost flat. The volume is the largest on the rivers course. And the river is most efficient as less water is touching the bed and banks.
The river is no longer eroding and there is minimal transport, most of the load is deposited as bed load.
The landform formed here are meanders (diagram in `middle course'). The meanders here are probably bigger than previously. The flat area of land by the river banks is the flood plain, the river is most likely to flood in this section.