Скачать или смотреть The River Valley - Courses & Profiles | AQA GCSE 9-1 Geography

What is the drainage basin? What are the key terms for drainage basins? What is the long profile of a river? What is the cross profile of a river? How does the river change from the upper course to the lower course?

This is the forty-third video for the AQA GCSE 9-1 Geography course, and the tenth video of the Physical Landscapes topic.

The Physical Landscapes Playlist:
»    • Physical Landscapes | AQA GCSE 9-1 Geography  

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Video Script:
The area of land drained by a river and its tributaries is known as a drainage basin. Tributaries are smaller streams that join larger rivers - the place where they join is the confluence. The source is the start of the river and the mouth is the end of the river - this is usually found at the sea. The watershed is the edge of the drainage basin. The load is the material carried by the river.

Now that you know the key terms, we can look at how the river valley changes over its course.

Rivers are split into three courses, the upper, middle and lower. The long profile shows the gradient of the river from its source to its mouth as you can see here. The cross-profile takes a cross-section of the river channel and the surrounding valley at specific points along the course.

The upper course has a steep-sided V-shaped valley with a narrow and shallow river channel. The gradient is steep which is due to more vertical erosion here, and more erosion than deposition. The velocity of the river is fastest in the upper course and the load is large and angular as it has not been eroded yet.

The middle course has a gentler gradient and a wider and deeper river channel. The river valley is much wider with a flat floor. The load is smaller and less angular.

The lower course has a very gentle gradient and the valley is very wide and flat. The river channel is at its widest and deepest. There is a large amount of sediment in the river but it is very small and round. Deposition is more common here.

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GCSE Geography
14/05/2023
Keducate