Capacity And Competence

Question 1

What is the capacity of a river?

Answer 1

A measure of the amount of material it can carry- the total volume of the load. Capacity is velocity3.

Question 2

What is the competence of a river?

Answer 2

The diameter of the largest particle that it can carry for a given velocity. Capacity is velocity6.

Question 3

What does they type, source and character of the load of the river depend on?

Answer 3

The nature of the drainage basin;
Location;
Human activity

Question 4

What factors affect spatial variations in load?

Answer 4

• size of the drainage basin
• rock type
• relief
• precipitation
• human activity

Question 5

What does the hjulström curve show?

Answer 5

The relationship between the velocity of a river and the size of particles that can be eroded, transported or deposited.

Question 6

What relationships have been found through the hjulström curve?

Answer 6

• sand particles are moved by a lower pick up or critical erosion velocities than smaller silts and clays or larger gravels
• particles can be carried at lower velocities than those required to pick them up
• the smallest particles are only deposited at very low velocities