Upland Landforms
River landscape characteristics
- The changes in river channel characteristics, lead to changes in the river landscape
- The upland and lowland areas of rivers have distinctive landforms
- Upland:
- Waterfalls
- Gorges
- V-shaped valleys
- Interlocking spurs
Waterfalls and gorges
- Waterfalls form when there is a drop in the river bed from one level to another
- This drop is often due to changes in the hardness of rock, where hard rock overlies soft rock
- Hydraulic action and abrasion are the main erosional processes:
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- The soft rock erodes quicker, undercutting the hard rock and creating a plunge pool
- This leads to the development of an overhang of hard rock which eventually over time, collapses
- The overhang falls into the plunge pool increasing abrasion and making the plunge pool deeper
- The process then begins again and the waterfall retreats upstream leaving a steep-sided gorge
Waterfall formation
V-shaped valleys
- Vertical erosion is dominant in the upper course of the river
- This cuts down into the river bed and deepens the river channel
- Weathering and mass movement leads to material from the valley sides collapsing into the river forming a steep v-shaped valley
Formation of a v-shaped valley
Interlocking spurs
- In the upper course of the river, the channel starts to meander
- Erosion happens on the outside of the bend
- In the upland areas this forms interlocking spurs
Interlocking spurs
Worked example
Explain the formation of a waterfall. (4)
- Identify the command word
- The command word is 'explain'
- Your focus is on 'waterfall'
- Answer: (you should include 4 points from the following)
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- Waterfalls occur where there is a step in the landscape often where hard rock such as dolerite overlays soft rock such as limestone (1)
- The soft rock erodes due to hydraulic action, at a faster rate than the hard rock (1) leading to undercutting and the formation of a plunge pool (1)
- This leaves an overhang of hard rock which eventually collapses due to gravity (1)
- The process is then repeated causing the waterfall to retreat upstream leaving a steep side gorge (1)