Physical Landscapes in the UK : Rivers Flashcards
Drainage Basin
An area oif land drained by a river and its tributaries
Source
Start of a river
Tributary
A smaller stream that joins a larger river
Confluence
Where a tributary joins a larger river
Watershed
Edge of a river basin
Mouth
End of a river, usually where it joins the sea
How does the cross profile of a river change as you go downstream?
Start - V-shaped valley, steep sided valley, narrow, shallow and turbulent river
Middle - Wider valley, flat floor, wider and deeper river
End - Very wide valley, flat, very wide and deep river with large sediment load
How does the long profile of a river change as you go downstream?
Upper course - Source, steep gradient, shallow but turbulent waters, slower rivers except for rapids (friction)
Middle course - Gentle gradient, deeper water with increased velocity
Lower course - Very gentle gradient, deep water with high velocity
Vertical Erosion
Erosion downwards
Lateral Erosion
Erosion sideways
Hydraulic Action
The force of the water hitting river banks and beds, causing erosion
Attrition
When stones carried byu the river collide against each other, gradually making them smaller and rounder
Abrasion
When load carried by river repeatedly hits the bed or banks dislodging particles into the flow of the river
Solution (process)
When river flows over limestone or chalk, the rock is slowly dissolved, because the water is mildly acidic
Traction
Large boulders and rocks are rolled along river bed
Saltation
Small pebbles and stones bounce along river bed
Suspension
Small particles are carried along by the water
- Silt or clay
Solution (physical)
Dissolved load
Typical Landforms in the upper course of a river
- Interlocking spurs
- V-Shaped valley
- Gorges
- Waterfalls
Typical Landforms in the middle course of a river
- Meanders
- Ox-Bow lakes
Typical Landforms in the lower course of a river
- Levees
- Flood plains
- River estuaries
Deposition
When the velocity of a river decreases, it no longer has enough energy to transport sediment, so it is deposited