4.6 Flashcards
What does it mean by the long profile of a river?
Long profile shows the steepness of a river as it goes from the source to the mouth.
How does the river Eden’s landscape change along its long profile (upper/middle/lower). Consider: channel shape, valley profile, gradient, discharge, velocity, and sediment size,shape and quantity.
In the upper course the channel shape is narrow and shallow, the valley profile shows that it is a v shaped valley , the gradient is steep, the discharge is low, velocity is high, sediment size is big and quantity is not a lot.
In the middle course the channel shape is wider and deeper, the valley profile shows that is is getting into a non steep sided valley, the gradient is less steeper, the discharge is higher, velocity is higher, sediment size is smaller and quantity is more.
In the lower course the channel shape is very wide and very deep, the valley profile shows that is is a u shaped valley, the gradient is not steep, the discharge is very high, velocity is very high, sediment size is very small or dissolved and quantity is large.
What are the reasons for these changes?
The reasons for these changes is that water erodes downwards at first, then laterally. Attrition makes rocks smaller and rounder. As it gets wider more water can store more kinetic energy and sediments can dissolve in liquids or be suspended.
Compare hydraulic action with abrasion.
Hydraulic action is the process of water and air going into cracks and causing high pressure so that it cracks even more and then breaks, but abrasion is using waves and rocks to hit the face of the clif so that the force of the wave and the rocks cause even more faults.
Define weathering.
Weathering is the process of breaking rocks down like freeze thaw, biological etc.
Compare freeze thaw and biological weathering.
Freeze thaw is where rain falls, freezes in the night, expands, melts in the day and repeats until it breaks off, but biological weathering is where roots and vegetation grows into the cracks and it expands and breakers off.
Compare traction with suspension transport.
Traction is where large sediment rolls on the floor along the river at the upper course. Suspension is where small sediment is suspended in the water along the river at the lower course.
Explain the stages and processes responsible for waterfall formation.
First water erodes downwards at the upper course and it is hard for it to break down hard rock so when there is soft rock it erodes and then it forms a plunge pool where sediment is churned around and then it erodes down into the plunge pool and back. Later it creates a gorge by eroding backwards more and gravity pulls the hard rockstar down and it repeats
Explain the stages and processes responsible for V shaped valley.
Either a river erodes downwards at the upper course of a valley and/or the water goes away by frozen soil and water leaving or a glacier has mowed down a massive chunk of land.
Explain the stages and processes responsible for interlocking spurs.
Inter locking spurs are created when a river moves and then it erodes down and the quickest route for the water to reach the mouth is the route where the spurs are.
Explain the stages and processes responsible for meanders.
Meanders are formed when the quickest route for water down a river is sideways than it puts force on the other side of the river bank and it erodes it and where it erodes is the fastest way for water so it will carry on meandering until it cuts of into an ox bow lake then an ox bow.
Explain the stages and processes responsible for flood plains.
This is when a river bursts its banks and then it leaves sediment on the ground and a flood plain is created, which is flat and very fertile.
Explain the stages and processes responsible for levees.
After the river banks breaks sediment gets released and larger sediment need more energy to transport it gets left near where the banks burst and then low and lower it goes and it forms a natural levee.
Explain the stages and processes responsible for deltas.
When a river reaches the mouth, the water slows down and loses energy to carry the sediment so the sediment is dropped at the mouth of the river in layers and it forms deltas.
Explain two ways climate change the river landscape.
Thermal expansion from the heat means that rivers levels will rise leading to higher chance of a flood happening and as glaciers melts all the water will flow into the drainage basin and increase river levels again.
