Water On The Land Knowledge Flashcards
Describe three features of the middle course
Medium sized valley
Lateral erosion
Transports its load
Describe two features of the lower course
Large valley
Flood plain
Describe hydraulic action
Sheer force of the water
Describe abrasion
Rivers load brushing on river bed and sides
Describe attrition
The load brushing against each other
Describe solution (erosion)
Water dissolving particles of the river and its load
Describe traction
Large boulders on river bed
Describe saltation
Pebbles bouncing along the river bed
Describe suspension
Small particles of mud in water
Describe solution
Minerals being dissolved in the water
Describe four features of the upper course
Small valley
Vertical erosion
Lots of energy
Erodes down
Describe the formation of a water fall (four marks)
Water runs over a strand of more resistant rock that is on top of a less resistant strand of rock. The less resistant rock erodes and forms an overhang. The overhang eventually becomes to big and collapses under its own weight. This process occurs repetitively
What occurs on the outside of a meander
River cliffs
Lateral erosion
Fast flowing
Why are meanders formed
Because the river wants to get the easiest route from A to B
Describe the inside of a meander
Slower current
Deposition occurs
Slip off slopes
What occurs at the outside of a meander
Current is faster
Erosion occurs
River banks form
Describe the formation of an ox bow lake
Starts with a tight meander
This becomes tighter (swan neck meander)
A straight channel is formed
Deposition occurs at the edges of where the old channel was isolating it
What happens to the water after it breaks the rivers banks, and what does this lead to
It slows down and it leads to deposition
Does a levee take many or few floods to form
Many
What does lag time mean
The difference between peak rainfall and peak discharge