- Created by: ellllllllllaa
- Created on: 27-05-19 15:57
V-shaped Valley- upper course
- Form as a river flows downhill.
- The rivers energy is focused on the river bed (vertical erosion).
- As it gets deeper the valley sides are worn away through weathering.
- This leaves steep valley sides, creating the V-shape.
2 of 14
Interlocking Spurs- upper course
- 'Pairs' of highland left either side of the valley.
- These are created as the river winds around areas of harder rock to find the easiest route.
3 of 14
Waterfalls- upper course
- A waterfall will form where hard rock overlays softer rock.
- The river will erode the softer rock quicker, creating a 'step' in the river bed.
- The water will then fall vertically from the hard rock to the soft rock below.
- The hard rock is under cut, meaning it loses support and overhangs the drop.
- Splash back causes hydraulic action to erode the rocks behind the fall of the water.
- Hydraulic action and abrasion cause a plunge pool to form where water and load swirl around, eroding the rock futher.
- The overhanging hard rock collapses into the plunge pool.
- As the undercutting continues, a new overhang is created and the process repeats.
- The waterfall retreats upstream leaving behind a gorge.
5 of 14
Gorges- upper course
- As the waterfall retreats upstream, it leaves a steep sided valley downstream called a gorge.
- Every time the overhanging rock breaks off, the gorge retreats and grows longer.
6 of 14
Meanders- middle course
- The current is faster on the outside of the bend because the river channel is deeper (there's less friction to slow the water)
- Therefore, more erosion takes place on the outside of the bend, forming river cliffs.
- The current is slower on the inside of the bend because the river channel is shallower (there's more friction to slow the water down)
- So eroded material is deposited on the inside of the bend, forming slip-off slopes.
8 of 14
Ox-bow Lakes- middle course
- Erosion causes the outside bends to get closer until there's only a small bit of land left between the bends (called the neck).
- The river breaks through this land, usually during a flood, and the river flows along the shortest course.
- Deposition eventually cuts off the meander forming an ox-bow lake.
10 of 14
Flood Plains- lower course
- The flood plain is the wide valley floor on either side of a river which occasionally gets flooded.
- When a river floods onto the flood plain, the water slows down and deposits the eroded material that it's transporting. This builds up the flood plain (makes it higher).
- Meanders migrate (move) across the flood plain, making it wider.
- The deposition that happens on the slip-off slopes of meanders also builds up the flood plain.
12 of 14
Levees- lower course
- Natural embankmets (raised areas) along the edges of a river channel.
- During a flood, eroded material is deposited over the whole flood plain
- The heaviest material is deposited closest to the river channel, because it gets dropped first when the river slows down.
- Over time, the deposited material builds up, creating levees along the edges of the channel, e.g. along the Yellow River in China
14 of 14