EQ4 – Why is there a variety of river landscapes/processes in the UK Flashcards
What is meant by the long profile of a river?
showing the gradient of the river and
how this changes with distance from 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 and shape?
Upper course: the rivers discharge is low, the river goes through vertical erosion (cutting down) they have a v shaped valley and interlocking spurs.
Middle course: the river goes through lateral erosion (erode sideways), the valley is widened and the river forms meanders and ox bow lakes.
Lower course: the river gets more widened and begins deposition, it eventually makes Deltas and bars of islands built by deposition.
Compare hydraulic action with abrasion
Hydraulic action is when air gets trapped in cracks of rock and the water pushes on it, the pressure gets too much and chunks of rock chip off, on the other hand abrasion is when rock smashes against cliffs chipping chunks of rock away eventually eroding the rock.
Define weathering
Weathering is the process that breaks down rock on the earths surface e.g. biological, freeze thraw
Compare freeze thaw and biological weathering
Freeze thraw weathering is when water gets into cracks and it freezes then expands chipping of rock and repeating this process, while biological weathering is when trees and plant roots dig under rock then animals burrow under as well, breaking off rock.
Compare traction with suspension transport
Traction is when large pebbles are rolled along the seabed and suspension is when pebbles are suspended and floating in the water.
Explain the stages and processes responsible for waterfall formation,
v shaped valleys and interlocking spurs, meanders, ox-bow lakes, flood
plains, levees and deltas.
Waterfall-hard layer of resistant rock over a soft layer of resistant rock, soft rock gets eroded, then the overhang collapses and the process repeats itself.
V shaped valleys- weathering erodes the side of the valley, slope transport and gravity pull the slopes down leaving a v shaped valley.
Meanders- the river erodes the outside of the bend washing away the river bank, over time the erosion and deposition change the course of the river making bends called meanders.
Ox bow lakes-in meanders abrasion causes the outside bends to get together and eventually break through making a bow shape, deposition eventually cuts off the meander leaving the outside bend known as an ox bow.
Label the key features (lag time, rising limb and peak discharge) of a flood hydrograph
Lag time- the time taken between the peak rainfall and the peak discharge
Rising limb-the rising of the river level
Peak discharge- when the heaviest rainfall occurred.
Compare a flashy and subdued hydrograph
A flashy hydograph is a graph that responds quickly to rain (high peak and short lag time)
While a subdued hydrograph has a long lag time and a low peak twlling us it takes longer for it to respond to rain.
Explain how physical factors (geology, soil, slope, basin type,
antecedent conditions) can affect flood hydrographs.
If there is a lot of saturated soil, there will be kore surface run off leading to a more higher peak discharge, a small basin with a small bank might not be able to hold much water in it too leading to a flashy hydrograph.
Explain how human factors (urbanisation, land-use change and
deforestation) can affect flood hydrographs.
Deforestation will mean for a higher peak discharge because of more surface run off,
Urbanisation and impermeable rock will also give more surface run off probably overflowing the river and giving the hydrograph a high peak.
Explain how physical and human factors cause river flooding in the River Eden.
Physical- lots of impermeable rock in the pennines , receives a lot of frontal rain from SW, snowfall is common.
Human- issues with the drainage, natural woodlands have been cleared, the urban city has lots of impermeable rock
What are the effects of flooding on people and environment? What problems were caused?
Destroyed houses, lots of money lost of insurance, people loose their properties, important documents from chuches, schools and even hospitals are lost, people cant do anything, people might die, animal habitats might be destroyed.
