Part 6: How do river landscapes change? Flashcards
- What processes of erosion are there in a river?
a. Hydraulic action
b. Abrasion
c. Attrition
d. Solution
- How does hydraulic action erode river banks?
a. Air is trapped in cracks
b. Pressure weakens the banks
c. The banks are gradually worn away
- How does abrasion erode river banks?
a. Rocks carried along by river
b. Bed and banks are worn down
- How does attrition erode river banks?
a. Rocks carried by the river
b. Smash together
c. Break into smaller, smoother and rounder particles
- How does solution erode river banks
a. Soluble particles are dissolved into the river
- How does a river transport material?
a. Traction
b. Saltation
c. Suspension
d. Solution
- Why does deposition happen in rivers?
a. The river does not have enough energy to carry material
b. Heaviest material is deposited first
- What features are found in the upper course of a river?
a. Waterfalls
b. Interlocking spurs
c. V-shaped valleys
- What features are found in the middle course of a river?
a. Meanders
b. Floodplain
- What features are found in the lower course of a river?
a. Oxbow lakes
b. Floodplain
c. Levees
d. Deltas
- What are interlocking spurs?
a. Small rivers flow around valley slopes
b. Created when river is small and does not have a lot of power
c. River erodes downwards
d. Create v-shaped valleys
- How are waterfalls formed?
a. Upper course of a river
b. Resistant hard rock over soft rock
c. River erodes less resistant rock faster
d. Harder rock undercut
e. Plunge pool formed
f. Overhang left
g. Hard rock collapses into the plunge pool
h. Waterfall retreats
i. Steep sided gorge formed
- How are meanders formed?
a. In middle course
b. River flows from side to side in the channel
c. Erosion undercuts where the flow is fastest
d. Deposition where the flow is slowest
e. Eroded parts of the channel is slip off slope
f. Deposited material in a river is point bar
- How are Oxbow lakes formed?
a. Middle to lower course
b. As a meander bends the neck becomes narrower
c. River floods the neck
d. Water flows through the new channel
e. Deposition seals off the bend
f. Bend dries out
g. Oxbow lake is formed
- What are floodplains?
a. The land a river floods onto
- How are floodplains formed?
a. Lower course
b. Formed by erosion and deposition
c. River floods into floodplain
d. Makes valley wide and flat
e. River deposits sediment
- What are levees?
a. Natural embankments of sediment next to a river
- How are levees formed?
a. The river floods
b. Heavier sediment is deposited
c. The river floods again
d. More sediment is deposited
e. Levees grow higher
- What happens to the river channel as the river flows from source to mouth?
a. Increases
- What happens to the width of the river channel as the river flows from source to mouth?
a. Increases
- What happens to the depth of the river channel as the river flows from source to mouth?
a. Increases
- What happens to the velocity of the river as the river flows from source to mouth?
a. Increases
- What is the load of the river?
a. The amount of sediment it carries?
- What happens to the river’s load as it flows from source to mouth?
a. Increases
- What happens to the size of the sediment in the river as it flows from source to mouth
a. Decreases
- What happens to the roughness of the river bed as the river flows from source to mouth?
a. Decreases
- What is the gradient of the river?
a. How steep the river is from end to end
- What happens to the gradient of the river as it flows from source to mouth?
a. Decreases
- What is the cross profile of the river?
a. The shape of the river from bank to bank
- What happens to the profile of the river as it flows from source to mouth?
a. Changes from V-shape to flatter
