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FLUVIAL LANDFORMS
OR RIVER FEATURES

Look at the video
https://www.youtube.com/watch?v=XHeYoz1LUd0

Copy and complete notes.
Draw diagram for each feature.

As the river flows from the source to the mouth, it can change the landscape. The type of change depends upon the nature of the terrain, the volume and speed of the river. Various processes operation throughout the course of the river.

THE UPPER COURSE

The part of the river which is nearest to its source is known as the upper course. In this section, the slope is steep, the river flows fast and erosion is plentiful. The river cuts downwards.

1. V- SHAPED VALLEYS – The river is deepened by vertical erosion. At the same time the valley is widened by weathering and mass wasting. As a result, the shape of the valley is typically like the letter “V”.
2. INTERLOCKING SPURS – rivers tend to take the easiest route down the slope. The river tends to avoid outcrops of more resistant rock by going round them. The river follows a winding course rather than a straight one.  Each bend is separated by a projection of highland known as spur. As you look upstream, these spurs overlap and interlock.

3. POTHOLES – When the river flows over an uneven bed, it causes the water to swirl. The pebbles carried in the water wear away circular depressions in the river bed. As the holes become wider and deeper it is called potholes.

4. RAPIDS – In some places, the gradient of the river may steepen. If this happens, the water will start to flow more quickly and will tend to be rough. Where this occurs it is called rapids.

5. WATERFALLS – In some places a river may descend vertically (over a cliff). This creates a waterfall. In the diagram below, the water flows over a horizontal layer of resistant rock over less resistant rock. As the water passes from the resistant rock to the less resistant rock, it will start to erode more rapidly. The soft rock at the base is undercut by the falling water. This develops into a plunge pool, which is often very deep.

6. GORGE/ CANYON – As a waterfall retreats upstream, it leaves a steep sided gorge. A series of gorges is called a canyon.

THE MIDDLE COURSE

Here the gradient is less steep. Lateral erosion now becomes more active than vertical erosion. The river develops a wider more open appearance. Some deposition also begins to take place.

THE LOWER COURSE – This section is nearest the mouth. The river flows through flat land. The river has greater volume of water. The river is wider and deeper and may contain a large amount of suspended sediment.
7. MEANDERS/ RIVER CLIFF/ POINT BAR – As the river widens its channels it becomes increasingly curved. Erosion occurs on the outside bend, where the water flows faster and friction is at a minimum. This area becomes deeper forming a river cliff. Material is deposited on the inside bend. This area becomes curved forming a slip off slope or point bar.

8. OX – BOW LAKE – These are shallow temporary features. They develop when a meander  becomes so pronounced that a very narrow neck of land separates the two end of the meander. During a flood, the river cuts through the narrow neck in order to shorten its channel. Deposition takes place at the cut ends of the meander. It is sealed off forming a crescent shaped feature called an ox- bow lake. It will eventually dry out.
9. FLOOD PLAINS - When the river floods over the surrounding land it loses energy and deposition of its suspended load occurs. Regular flooding results in the building up of layers of nutrient rich alluvium which forms a flat and fertile floodplain. When the river water bursts its bank, the shallower depth of water flowing over the surface results in frictional drag and a consequent reduction in velocity (speed) of flow. This results in the loss of energy and therefore deposition occurs.

10. LEVÉES – The heaviest materials are deposited first as these require the most energy to be transported and therefore build up around the sides of the river forming raised banks known as Levées.  Finer material such as silt and fine clays continue to flow further over the floodplain before they are deposited.

11. BRAIDED STREAMS – are created when the discharge of water cannot transport its load. When there is a decrease in stream velocity sediment is deposited on the floor of the channel creating bars. The bars separate the channel into several smaller channels creating a braided appearance.

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Take a pic of the work that you have completed and email it to
debra_ramrekha@hotmail.com

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LESSON 3                          RIVER PROCESSES

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LESSON 3                          RIVER PROCESSES

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*  Look at video.
* Copy and complete in your notebooks.
* Draw diagrams

As the river flows from the source to the mouth, it can change the landscape. The type of change depends upon the nature of the terrain, the volume and speed of the river. Various processes operate throughout the course of the river.
https://www.youtube.com/watch?v=ewJimXu3ZLo

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LESSON 2                               The Drainage Basin

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LESSON 2                               The Drainage Basin

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COPY AND COMPLETE NOTES

A drainage basin (catchment) is an area of land within which water collects and is drained by a river and its tributaries.

The perimeter of the basin is a called a watershed.

A drainage basin is a system with inputs, outputs, transfers and storage. The input is precipitation. The main output is river discharge – the flow of river water out of the basin and into the ocean. Evaporation and transpiration are also outputs as water is lost to the atmosphere.

Water is stored in a variety of ways – vegetation, lakes and ponds, clouds and in the soil as groundwater. The permeable rock which stores this water is called an aquifer.
Look at the video
https://www.youtube.com/watch?v=OmX76AOb3qo
- Draw a diagram and label the following:
1. drainage basin
2. main river channel
3. tributaries
4. watershed
5. source
6. mouth

- Place the following
( river discharge, precipitation, snow melt,  evaporation, percolation, interception, condensation,  lake, groundwater, throughflow, vegetation)
in a table under the  headings:
Inputs     Outputs   Transfers   Storage

- Define the term water table.
- Draw and label a diagram of the water table.
- What is the difference between a spring and a well?

Look at the video
https://www.youtube.com/watch?v=1iWgjurJpzE

List the factors influencing drainage.
Draw and label diagrams for each DRAINAGE PATTERN.
DEFINE EACH.

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LESSON 1                              The water cycle

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LESSON 1                              The water cycle

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This term we begin with The Hydrological Cycle.
TERMS IN LESSON
•CYCLE – a series or sequence of events that are regularly repeated in maintaining the same order.

•ATMOSPHERE – the air that surrounds earth.

•LITHOSPHERE – the solid outermost part of the earth.

•HYDROSPHERE – is the liquid water component of the Earth. It

includes the oceans, seas, lakes, ponds, rivers and streams.

Use link to view a video.
https://www.youtube.com/watch?v=IO9tT186mZw

What you need to do……
•Draw and label the water cycle

•Explain each process

•Explain how water changes state during various processes in the cycle

•Explain the importance of trees in the cycle.
State the percentage of water in each of the following:
1. oceans and seas
2.  lakes, ponds, rivers and   streams.
3. ground water
4. ice
5. atmosphere