3.1.3.3 River landscapes in the UK Flashcards
What is transpiration?
Tree roots absorb water and evaporate it out
What is precipitation?
Water falling to earth (snow, rain, sleet, hail)
What is infiltration?
Water penetrating ground after it has landed
What is percolation?
Water going from soil to rock underground
What is interception?
When the water lands on vegetation
What is surface run-off?
Water flowing over the surface towards river
What does the long profile of a river show?
Shows you gradient (steepness) changes over different courses
What does the cross profile of a river show?
Shows cross-section of river
What is the main process in the upper course of a river?
Erosion (wear landscape down)
What is the gradient in the upper course of a river?
Steep
What is the shape of the valley in the upper course of a river?
V-shaped valley
What is the channel like in the upper course of a river?
Shallow and narrow
What is the upper course of a river closest to?
The source of the river
What is the main process in the middle course of a river?
Transport (material)
What is the gradient in the middle course of a river?
Medium
What is the shape of the valley in the middle course of a river?
Gently sloping valley sides
What is the channel like in the middle course of a river?
Deeper and wider channel
What is the main process in the lower course of a river?
Deposition
What is the gradient in the lower course of a river?
Gentle
What is the shape of the valley in the lower course of a river?
Almost flat valley
What is the channel like in the lower course of a river?
Very wide and deep
What is the lower course of a river closest to?
The mouth of the river
What can change the cross profile of a river?
Vertical & Lateral Erosion
What does vertical erosion do to a river valley?
Deepens river valley (and channel) = makes it V-shaped
Where is vertical erosion most dominant in a river?
Upper course
Describe the process of vertical erosion
High turbulence causes rough, angular particles to be scraped along river bed = intense downwards erosion
What does lateral erosion do to a river valley?
Widens river valley (and channel) during formation of meanders
Where is lateral erosion most dominant in a river?
Middle and lower courses
Name the 4 processes of erosion
- Hydraulic action
- Abrasion
- Attrition
- Solution
What is hydraulic action?
Force of water breaks rock particles away from river channel
What is abrasion?
Eroded rocks (river’s load) scrape and rub against channel, wearing it away
What is attrition?
Eroded rock (river’s load) smash into each other and break into smaller fragments
What is solution (erosion wise)?
River water dissolves some types of rock (e.g. Chalk &
Limestone)
How does most erosion occur?
By abrasion
What happens to material the further it travels along the river?
Gets more eroded and the edges get rounded off as
rubbed together
What causes the particle size to decrease between river’s source and mouth?
Attrition
What is transportation?
Transportation is the movement of eroded material
Name the 4 methods of transportation?
- Traction
- Saltation
- Suspension
- Solution
What is traction?
Large particles like boulders are pushed along river bed by force of water
What is saltation?
Pebble-sized particles are bounced along river bed by force of water
What is suspension?
Small particles (slit & clay) are carried along by water
What is solution (transportation wise)?
Soluble materials dissolve in water and are carried along
What is deposition?
When river drops eroded material it’s transporting
When does deposition occur in a river?
Happens when river slows down (loses velocity)
Name 4 reasons why a river slows down and deposits material
- Volume in water (in river) falls
- Amount of eroded material in water increases
- Water is shallower e.g. On inside of bend
- River reaches mouth
Where are waterfalls and gorges are found in a river?
Upper Course
What process causes waterfalls and gorges to form?
Erosion
Where do waterfalls form?
Where river flows over hard rock followed by softer rock