Rivers Flashcards
What does a river long profile show
The long profile shows how a river’s gradient changes as it flows from its source to its mouth
Define source
Where a river begins
Define drainage basin
The area from which water drains into the river
Define watersheds
An imaginary line that separates 2 drainage basin
Define confluence
The point where 2 rivers join together
Define tributaries
Smaller rivers which join the main river
Define flood plain
Land that floods when a river overflows
Define mouth
Where the river flows into the sea or lake
Define river bed
The bottom of a river channel
Define river bank
The side of a river channel
Define channel
What the river flows in
Whats the upper course of the river
The steepest part of land in the river, small but flows quickly, energy levels are high and the river cuts away at its bed. As it does it quickly deepens its valley through down cutting which creates a steep sided v shaped valley.
Whats the middle course of the river
River starts to flow slowly because it starts to transport lots of sediments as rivers look muddy. As the river moves down its valley a number of changes occur. The river gets wider as more tributaries join together
What are the 4 changes that occur in the middle course
- The valley sides become less steep, giving the shape of a open V
- The river begins to erode sideways into its bank. This opens out the valley floor and a flood plain starts to develop
- Erosion and deposition occur
- The edges of the floodplain are marked by bluffs
What is the lower course of a river
When the valleys V shape is so wide that the valley sides have been disappeared. The river approaches its mouth. The river now winds its way slowly across a large flood plain. Deposition is now dominant process
Define erosion
Gradual removal of rock from a rivers bank and bed
Define abrasion
Rocks carried along by the river wear down the river bed and banks.
Define hydraulic action
The force of the river against the banks can cause air to be trapped in the cracks. The pressure builds, weakening the bed and banks and gradually wearing them away
Define solution
Soluble particles and minerals are dissolved inti the river
Define attrition
Rocks being transported by the river smash together and break into smaller rounder and smoother pieces
Define gradient
A steep gradient results in the river water being pulled by gravity, cutting down and eroding the channel
Define rock resistance
Erosion rate increases more erodible the rock is
Define solution (deposition)
Minerals are dissolved in the water and carried along in solution
Define suspension
Fine light material is carried along in the water
Define saltation
Small pebbles and stones are bounced along the river bed
Define traction
Large boulders and rocks are rolled along the river bed
Define capacity
Maximum amount of things a river can carry= overall weight of the load
Define competence
Largest sized individual particles a river can carry = the largest rock it could movel
Define artificial levees
Where people build up the height of a bank ( piled earth or coated in concrete) to limit the change of a river flooding
Define estuaries
The tidal part of a river where fresh water from the river merges with the salt water from the sea
