River Courses Flashcards
Where is a river steepest?
Upper course
Where is a river most deep?
Lower course
Where is the river most narrow?
Upper course
Where is a river most shallow?
Upper course
How does the discharge change as a river moves through its course?
Discharge starts low at upper but then becomes high at the lower course
What will the gradient be like at the lower course?
Flat or low
Where is the river widest?
Lower course
What kind of valleys are in the upper course?
V-shaped valleys
What kind of valleys are in the lower course?
More semi circular u shaped valleys
Where does lateral erosion occur?
Lateral erosion occurs in the middle and Lower course
Why will rocks in the lower course be smaller?
Because of attrition taking affect over the whole course of the river
What does the lower course of a river have because it is flat?
Flood plains
Give some features of the upper course
Shallow in depth, narrow, steep, slow flow
Give some features of the middle course
Flatter valley, faster flow, lateral erosion, wider
Where does vertical erosion occur?
Upper course
What erosional processes occur in the lower course?
Transportation and deposition
Give some features of the lower course
Most energy, widest, flatter, deeper, meets the sea
What landforms are found in the upper course?
Waterfalls, gorges, v -shaped valleys, interlocking spurs and the source
Why are valleys shaped as a v in the upper course?
The river erodes vertically down causing the sides to be attacked by weathering processes, weakening them and causing mass movement processes.
Interlocking spurs are…
Areas of more resistant rock in a v shaped valley as the softer rock has eroded away
When do waterfalls form?
When a river is on two bands of hard and soft rock.
What are the steps to waterfall formation?
- Less resistance rock eroded by hydraulic action and abrasion
- Hydraulic action continues undercutting and creates a pluge pool
- Overhang created collapses and waterfall retreats upstream
- a steep sided gorge is left
Where is the waterfall in Northumberland located?
River Tees near Middlestone and Teesdale
How tall is the waterfall in Northumberland ?
20m
Give an example of a meander in the river Tees
Yarm
Water does what on the outside bend of a meander?
Flows faster
What is a slip off slope?
Where a river deposits material because the bed is more shallow on the inside of a meander
What is an oxbow lake?
A small horse-shoe shaped lake that is not connected to any other river channels
How does an oxbow lake form ?
As the neck of a meander gets narrower, fast flowing water eroded a more efficient channel and breakers through the land between a meander in times of a flood. Then alluvium is deposited between the new river channel and meander causing it to get cut off and eventually dry up
What landforms are found in the middle course?
Oxbow lakes and meanders
What is a helicoidal flow?
A continuous corkscrew motion of water as it flows along a river channel
What is a river cliff?
Steep edge of a river
Landforms in the lower course are…
Levees, floodplains, large meanders and oxbowlakes
Where are deltas found?
In the lower course of a river with high load as it starts to slow down
What are floodplains?
Wide flat areas of land either side of a river liable to floods
What is a levee?
An embankment built up on either side of a river after flooding
Where is the mouth of the river Tees?
In the North Sea between Hartlepool and Redcar near Middlesbrough
How may deltas be useful to humans?
They provide new farming grounds as the land is extremely fertile
Describe a fan shaped delta with an example
When land around the river mouth arches out to sea, splitting the river many times creating a fan affect e.g. river Niger in Nigeria
What is a cuspate delta and give an example?
When the land around a river just out, arrow like, into the sea e.g. river Ebro in Spain
Describe Bird’s foot delta and give an example
When a river splits lm the way to sea and each part of the river just out to sea like a bird’s foot e.g. Mississippi River in the USA
What is a delta?
A low lying area at the mouth of a river where it deposits so much sediment that it extends beyond the coast
