4.6- Landscapes and processes Flashcards
What is meant by the long profile of a river?
The long profile of a river shows you the gradient changes over the different courses. The path of a river from start to end, twisting, meandering, steepness and direction mainly.
How does the river Eden’s landscape change along its profile (upper/middle/lower)?
In the upper coarse it is very steep. The middle coarse it levels out a tiny bit and eventually in the lower coarse it levels out and gains a higher velocity.
What are the reasons for these changes?
.valley sides are effected by river flow, rounder rocks are found in the upper coarse as they have had less erosion, whereas in the middle and lower coarse the sediment and smaller as it has been more finely eroded.
Compare hydraulic action with abrasion
Hydraulic action is when water hit hard against rocks and surfaces to cause erosion. Abrasion is when rocks scrape or hit to wear away each other and cause the rocks to become smaller and finer.
Define weathering
Weathering breaks down rocks on valley sides, freeze thaw weathering is a type of mechanical weathering. It is the act of wearing away of changing the appearance of rocks.
Compare freeze thaw and biological weathering
Freeze thaw weathering is when water enters cracks and freezes, expands and creates them larger. Biological weathering is when rocks are weakened by the growth of plants and animals in the ground and cracks.
Compare traction with suspension transport
Traction is when large boulders and rocks are rolled along the river bed, gradually becoming smaller. Suspension transport is when fine material is carried along in the water and rarely colliding with other sediment as they are so small.
Explain the stages and processes responsible for waterfall formation.
- Waterfall occurs when a river falls on more resistant rock on top of less resistant.
- Less resistant rock erodes underneath by hydraulic action and rubbing
- Swirling gradually erodes the river bed (plunge pool)
- Eventually, the overhang of the more resistant rock collapses.
- The collapse of the more resistant rock results in further erosion of less resistant rock
- This results in the waterfall eroding downstream forming a steep sided valley called a ‘gorge’
Explain two ways climate, geology and slope processes change the river landscape.
Air temperature is rising from climate change and holds more moisture. Extreme storms are more likely to occur and can effect the river structure dramatically.
Hydrograph - Lag time
The time between max8mum rainfall and peak discharge of the river. Evacuation period for the people to leave
V-shaped valley
Begins with a river flowing through a landscape, which erodes deeper into the landscape, the raised embankments of the river become loose due to weathering and collapse, the fallen sediment is taken away don the river and a v shape is left behind to the valley.
Factors affecting hydrographs
Type of drainage basin, how permeable. Lag times and other landscapes. As to how much water can be absorbed and where it would be stored - basing the level of depth.
