Geomorphology

Landforms of Fluvial Erosion

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1. Waterfalls

What part of the river course would you expect to find this feature?

Identify 3 features of this waterfall?

How does this feature move upstream?

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1. Waterfalls

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2. Rapids

What type of river flow is characteristic of rapids?

What process of river erosion has produced the rounded river stones and rocks?

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3. Potholes

Describe the three processes of erosion responsible for the formation of potholes?

What role do the narrow river gorges play in the process?

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4. MeandersIdentify the two types of slopes or banks of a meander

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4. Meanders

Which bank of the meander does this photo show?

How does this bank develop?

What problems could such a feature cause in an urban area?

How do town planners solve this problem?

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Direction of Erosive Action

Describe the direction of erosion in the upper course of a river that leads to the formation of waterfalls and rapids.

Describe the direction of erosion in the middle and lower courses of a river that leads to the formation of meanders.

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5. Oxbow Lakes/Meander Scars

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Formation of Oxbow Lakes

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Formation of Oxbow Lakes continued

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Formation of Oxbow Lakes continued

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Formation of Oxbow Lakes continued

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Formation of Oxbow Lakes continued

In meandering rivers, sediment is eroded on the outside of bends (undercut banks) and deposited on the inside of bends (slip off slope)

Over time, this causes meander loops to migrate downstream

If the movement of one meander loop overruns the next one downstream, then a meander cut-off is formed

This causes the course of the channel to be shortened as the two meander loops join

The abandoned meander loop is gradually isolated as sediment is deposited at each end by the water flow in the main channel. This process eventually leads to the creation of an oxbow lake

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