EQ4 and 5 - why is there a variety of river landscapes/ processes in the UK? Flashcards
What is the long profile of the river?
The long profile of a river shows how the rivers gradient in the upper course of the river is steeper but when it gets nearer the mouth gets flatter
How does river Edens landscape change along its landscape (higher,middle, lower)
The river eden starts at the source through the V shaped valleys into the interlocking spurs, reentering the wider channel. In the middle course of the river Eden there are meanders and oxbow lakes, and in the lower course you can get floodplains and deltas which turn into levees.
What are reasons for these changes?
Erosion when river water wears down rock, river discharge decreases and land formation changes
Compare hydraulic action with abrasion
Hydraulic is where rocks are being carried along by the river and air is trapped in its cracks. The pressure weakens the banks and gradually wears it away, abrasion - rocks carried along by the river wearing down the banks
Define weathering
Where rock is broken down by certain types of weather
Freeze thaw and biological weathering comparison
Where water gets into tiny cracks in the river and freezes and then melts again weakening the rock where as biological weathering is where vegetation intercepts rocks to wear it down and erode it
Compare traction with suspension transport
Traction is large boulders and rocks being rolled along the riverbed and suspension is fine light material being carried along in water
Formation of waterfalls
Water erodes against an alternating layer of hard and soft rock. The soft rock is eroded forming a plunge pool and deepened through the soft rock by hydraulic action, an overhang is created with the hard rock and collapses forming a waterfall
V shaped valleys formations
The discharge is low in the upper course and the river only has the energy to erode downwards. Weathering breaks down the valleys sides. The weathered material is transported towards the river channel steepening valley sides. Where there are resistant bonds interlocking spurs are formed.
Interlocking spurs formation
As the river erodes it winds and bends to avoid hard rock created interlocking spurs
Ox bow lakes formation
Erosion makes the neck of the river narrow, rivers cut through the neck during floods , the meander/ ox bow is cut off straightening the river.
Flood plain formation
Made by meanders erdoing sideways as they travel down stream
Levees formation
At the edge of the channel sediment is deposited at channel edges, the sediment builds up
Delta formation
When a river reaches the lake or sea slows down and loses power to carry sediment. Some rivers drop so much sediment it builds up in layers forming a delta.
How does climate change effect rivers
More floods and heavy stroms because water is evarporated from oceans and results in heavy precipitation
