Rivers - keywords Flashcards
What type of land forms take place on upper course of a river?
Erosion land forms (e.g. waterfall, gorges)
What type of land forms take place on the middle course of a river?
Erosion and deposition land forms (e.g. meanders)
What type of land forms take place on the lower course of a river?
Deposition land forms (e.g. levees, estuaries)
Hydraulic action
Force of water hitting the bed and banks causes material to break off
Abrasion
When the load carried by the river repeatedly hits the bed and banks which dislodges particles
Attrition
Stones carried by the river knock against each other, creating smaller, rounder pebbles
Solution (erosion)
When river flows over chalk/limestone, rock is slowly dissolved by acidic river water
In what course is the river at its fastest?
Lower course - as the channel is wider and there is a greater volume of water, less friction occurs and this causes a fast flow
Traction
Large boulders roll along the river bed
Solution
Dissolved load is carried in the water
Suspension
Small sediment is held in the river
Saltation
Particles too heavy to be suspended bounce along the river bed
Vertical erosion
Downward erosion of the river bed
Lateral erosion
Erosion of the river banks rather than river bed
Channel width
Distance from one bank to another
