The Long Profile

Question 1

Upper course

Answer 1

Predominantly erosion

Vertical Erosion dominant, almost no depostion

Greater GPE

Question 2

Middle Course

Answer 2

Predominantly transportation

Decreasing gradient

Lateral erosion (valley widening), some deposition

Question 3

Lower Course

Answer 3

Deposition dominant

Alluvium deposition

Some lateral erosion

Question 4

Concave shape

Answer 4

The steep reduction in height near the source gives way to a more gradual reduction further downstream, giving a typical concave profile.

Question 5

Why is there more GPE in the upper course?

Answer 5

The river has much potential energy near the source due to the steep drop

Question 6

Hydraulic action

Answer 6

The sheer force of the water breaks parts of the river banks through penetration of the cracks and gaps, forcing their breakdown.

Question 7

Abrasion

Answer 7

Is the sandpaper effect of rocks grinding against the bed and banks.

Question 8

Attrition

Answer 8

Rocks within the channel smash into each other and break up

Question 9

Corrosion

Answer 9

When very fine mateiral is dissolved in the water, ususally Calcium Carbonate (limestone+chalk)

Question 10

Consequence of corrosion

Answer 10

less material being carried by the river as very fine material is in a state of solution

Question 11

Factors that affect rate of erosion

Answer 11

Weight of the water

Gradient of slope (water gains speed)

The height of the water, the greater the GPE it contains

Question 12

Traction

Answer 12

large stones and boulders are rolled along the river bed by the water moving downstream

Question 13

Saltation

Answer 13

Stones bouncing along the river bed- easily seen (bed load)

Question 14

Suspension

Answer 14

Fine material is carried along by the river.

If river slows material can be dropped, causing build up of silt in river and canals.

Question 15

Solution

Answer 15

material is dissolved in the water and is carried along by it.

Question 16

River Transport

Answer 16

Solution

Suspension

Saltation

Traction

Question 17

Reasons for deposition

Answer 17

Reduction in velocity

Sudden rise in river’s load e.g. landslide into river

Evaporation of water

Question 18

Factors affecting fluvial processes

Answer 18

River volume

River speed/velocity

Slope

Width, Depth, of channel

Load

Question 19

Erosion Processes

Answer 19

Hydraulic Action

Attrition

Abrasion

Corrosion

Question 20

What is the Hjulstrom Curve?

Answer 20

Special type of graph that shows how a river’s velocity affects its competence and its ability to erode particles of different sizes.

Question 21

What are the two curves with Hjulstrom?

Answer 21

a critical erosion velocity curve and a mean settling velocity curve.

Question 22

What does the critical erosion velocity curve show?

Answer 22

shows the minimum velocity needed to transport and erode a particle.

Question 23

What does the mean settling velocity curve show?

Answer 23

shows the minimum speed that particles of different sizes will be deposited by the river.

Question 24

What do the shaded areas between the curves show?

Answer 24

the different process that will be taking place for particles that lie in those shaded areas.

Question 25

What do the axis represent on the curve?

Answer 25

X- Particle size (mm)

Y- Velocity (cms1)