Chapter 11-rivers Flashcards
Stages of a river
Upper/young
Mature/middle
Lower/old
Features of a upper river
- Steep fast flowing
- Little water
- Lots of erosion
- Narrow, shallow channel
Features of the middle of the river
- River starts to slow down
- More water
- Still eroding
- Wider,deeper channel
Stages of a lower river
Slow moving river
Much more water
Depositing not eroding
Very wide, very deep channel
Ways of river transportation
Rolling,bouncing,suspension,solution
Explain a way of river transportation- rolling/traction
The larger stones are rolled along the bed of the river. This process is known as traction
Explain the transportation process of bouncing/ saltation
The smaller pebbles are bounced along the bed of the river.
Explain the process of transportation called suspension
Light materials such as sand and silt float along in the river
Explain the process of transportation called solution
Materials dissolve in the water and are carried along by the river
Name the ways of river erosion
Hydraulic action, abrasion,attrition, solution
Name some youthful stage features
Waterfall,v- shaped valleys . Interlocking spurs
Explain hydraulic action
The force of the moving water wears away the banks and the bed of the river
Explain abrasion
Small stones carried by the river wear away the banks and bed of the river
Explain attrition
The small stones in the river are worn down and broken up as they hit off each other
Explain solution
Rocks such as limestone and soil are dissolved by acids in the water
Explain the feature of a waterfall
A waterfall is a rewrite of river erosion in the youthful stage of a river
A waterfall is a point where the is a interruption in the river profil and the water makes a vertical drop
Name a example of a waterfall
Tork waterfalls, Killarney, co.kerry
Explain waterfalls
Waterfalls develop when a layer of hard rock lies on top of a layer of soft rock. The soft rock is eroded by abrasion and by hydraulic action. The hard rock is overcut creating a overhang. The water falls into softer rock below forming a plunge pool a soft rock continues to be eroded at much faster rate than the hard rock. The hard rock is no longer supported and the overhand collapses
What is a v-shaped valley
It is a valley that is a steep sided valley in the shape of a v
What are interlocking spurs
They are the areas of high ground that jut out at both sides of a v-shaped valley
Name a mature stage freature
Meanders
Explained a meanders feature
Meanders are curves or bends that develop along the mature course of a river
Name a example of a meander
The river Shannon and the river moy
Explain meanders
As the water grows around a slight bend,the water at he outer or concave bank is deeper and flows more quickly as a result it has more power to erode the bank through hydraulic action and a river cliff forms
The water at the inner/convex bank is shallower and flows more slowly. As a result deposition occurs creating a pant bar
Erosion and deposition continue overtime and the meander becomes mor prominent
What is a oxbow lake
An oxbow lake is a horseshoe shaped lake that was formed when a meander was cut off from the river
Case study: anchacrusha power station, Shannon
Th power station was built in the 1920s by the Irish government
It was built by a German company,Siemens,and cost 5 million
How was the power station built
At first people thought that the land at river Shannon flowed through was to flat to harness hydroelectric power. To over come this wier was built to split the course of the river Shannon in two one section was a continuation of the natural course of the river. The other section was raised up called a headrace canal and directed water straight to the power station. The pressure of the flowing water is used to turn turbines and generate electricity
What is a source
It is the beginning or start of a river
What is a course
It is the route the river is going
What is the confluence
It is the point where two rivers join together
What is a tributary
A stream or smaller river that flows into a larger stream or river
What is the mouth of a river
The point where a river comes to a end
What is the drainage basin
Th area of land drained by a river
What is the watershed
The edge of highland surrounding a drainage basin
What is the estuary
The part of a river mouth that is tidal
What are features of the old stage
Levees,floodplains,deltas
Explain a feature of deposition with example
Levees are raised banks of alluvium along the bank of some rivers in their old age. Levees can naturally occur but can also be man made
Leaves form because of flooding. During normal flow the river is confined in its channel and deposition will occur on the river bed. However during flood events the river overflow it’s channel and pours over the floodplain. When a river floods and spreads out over the floodplain it looses its energy and begins to deposit load. The heavier material is deposited close to the banks while lighter materials is carried further across the floodplain. After many periods of flooding these deposits build up to form levees
River Shannon and river may
Explain alluvium
Clay,silt,sand
Advantages of the powerstation
The power station at and crusher allows the generation of hydroelectric power – a clean, renewable source of energy. When the power station was built it provided Ireland with 96% of its total energy. Between 1822–1930 The number of people employed in industry grew by 30,000. The production of cheap reliable electricity meant that Irish industry could grow. The dam built at ardchrusha and the Weir control the flow of water and limit the risk of flooding along the river Shannon
Disadvantages of the powerstation
The dam acts as a well across the river Shannon. Water builds up behind it creating a reservoir. The reservoir flooded the farmland leading to a loss of fertile, productive farmland. Some families had to re-locate and move on because of flooding caused by the river Reservoir.
