Rivers Part1

Question 1

3 main things rivers do

Answer 1

Erode-the land
Transport-rock particles and dissolved sediment
Deposit-the transported material

Question 2

Rate of erosion is effected by:

Answer 2

Load-the heavier and sharper the load the greater chance of erosion
Velocity-greater velocity greater potential for erosion
Gradient-increased gradient increases rate of erosion
PH-solution increases where water is more acidic
Human impact-deforestation,dams and bridges interfere with flow of river and increasing rate of erosion

Question 3

4 types of erosion

Answer 3

Abrasion

Attraction

Hydraulic action

Solution

Question 4

Abrasion

Answer 4

eroded rocks picked up by river scrape and rubbed against the channel, wearing it away

Question 5

Attraction

Answer 5

Eroded rocks picked up by the river smash into each other and break into smaller fragments. Edges rounded off as the rub together

Question 6

Hydraulic action

Answer 6

Force of water breaks rock particles away from river channel

Question 7

Solution

Answer 7

River water dissolves types of rock

Question 8

4 types of Transportation are:

Answer 8

Traction

Saltation

Suspension

Solution

Question 9

Traction

Answer 9

Large particles like boulders are pushed along the river bed by force of the water.

Question 10

Saltation

Answer 10

Pebble sized particles bounded along the river bed by force of water

Question 11

Suspension

Answer 11

Small particles like silt and clay carried along by water

Question 12

Solution

Answer 12

Soluble materials dissolve in water and are carried along

Question 13

Deposition

Answer 13

Is when a dive drops or leaves behind material that’s it’s been carrying

Question 14

Long profile

Answer 14

A line representing course of a river from its source to its mouth where it begins and changes in height along its course

Question 15

Cross profile

Answer 15

A line that represents what it would be like to walk from one side of a valley across the channel and up other side

Question 16

Upper course of river

Answer 16

• steepest slope
• narrow stream
• rocky bed
• most erosion
• source

Question 17

Middle course of river

Answer 17

• less steep
• quite wide stream
• less rocky
• erosion and deposition

Question 18

Lower course of river

Answer 18

• flatter slope
• wide river
• smooth bed
• fasted flow
• river appears to move slowly
• deposition
• mouth

Question 19

Meanders

Answer 19

Bends in the rivers course

Question 20

Waterfalls

Answer 20

1. Hard rock lies above soft rock
2. soft rock erodes more quickly due to hydraulic action and abrasion
3. Hard rock is undercut and overhangs as erosion of soft rock continues
4. Plunge pool is created at base of waterfall
5. Then hard rock collapses into plunge pool as can’t support its own weight
6. Waterfall retreats upstream forming a steep sided gorge
7. Process begins again

Question 21

Outside of meander

Answer 21

Water is deeper, current flows faster

Force of water erodes and undercuts outside bend by abrasion forming steep bank called a river cliff

Question 22

Inside bend of meander

Answer 22

Current is less strong encourages deposition

Question 23

Oxbow lakes

Answer 23

• A bend in river forms called a meander
• Neck of meander gets narrower over time due to continued erosion on outer bend
• Due to continued erosion beck get narrower and during a flood water travels straight across making quickest route
• River deposits rock and soil cutting off the meander creating ox-bow lake.