Rivers Flashcards
What is a drainage basin?
A drainage basin is an area of land drained by a river nd it’s tributaries
What does the long profile of a river show?
Shows how a rivers gradient changes as it flows from the source to its mouth
What does the cross profile show ?
The cross profile of a river shows the shape of the river Chanel
Where does vertical erosion take place ?
In the upper course of the river
Where does lateral erosion take place?
In the middle to lower course of the river
Where is a v shaped valley located?
In the upper course
What is erosion ?
The gradual removal of rock from a rivers banks and riverbed
4 types erosion
Hydraulic action- force of the river causes air to become trapped in cracks and crevasse causing the pressure to build
Solution- soluble particles and minerals are dissolved into a river.
Abrasion-rocks carried along by the river wear down river bed and banks
Attrition- rocks carried by river smash together breaking into smaller and smoother pieces
What are interlocking spurs?
The upper course of the river has less energy so it eroded the easier path . This forms spurs that appear to interlock
4 types of deposition and transportation…
Suspension- fine and light material is carrried along in the water
Solution- minerals are dissolved in water and carried along in the solution
Saltation- small pebbles and stones bounced along the riverbed
Traction- big boulders and rocks rolled along the river bed.
Factors leading to deposition include…
Velocity of water slowing ( the energy the river has )
Shallow water
When the volume decreases
At the end of a rivers journey at the mouth
Formation of a waterfall
Step1-hard rock over soft rock, soft rock is eroded
Step2- after a while a plunge pool is created
Step3- over time the hard rock overhang is unsupported, and it falls
Step 4- overtime the waterfall retreats upstream forming a gorge .
What’s helicoidal flow?
Corkscrew motion in a river caused by uneven riverbed.
What’s a meander?
Where’s it found ?
How’s it formed?
A bending curve in the river
Found in middle / lower course
Formed due to erosion and deposition
What’s the Thalweg line?
A line of fastest flow in a river Channel
What is an oxbow lake?
A semicircular area that represents the former course of a meander