Hjulström graph Flashcards Preview

AS-Level Geography Physical > Hjulström graph > Flashcards

Flashcards in Hjulström graph Deck (7)
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1
Q

What is competence?

A

competence is the maximum size of material which a river is capable of transporting.

2
Q

what is capacity?

A

the total load actually transported.

3
Q

What is the pick up curve?

A

-The pick up curve, or mean/critical erosional velocity curve gives the approximate velocity needed to pick up and transport particles of various sizes in suspension.

4
Q

What is the drop curve?

A

-The drop curve, or mean falling/settling velocity curve shows the velocities at which particles of a given size become too heavy to be transported and so will fall out of suspension and be deposited.

5
Q

What does the Hjulström graph show?

A

the relationship between velocity and particle size , for example competence.

6
Q

The graph shows that velocity to require sand is lower than clay. Why is this?

A

Clay has cohesive properties; it tends to bond together, therefore requiring more energy to lift it. Sand on the other hand is granular and does not tend to bond together.

7
Q

What is the difference between the velocity to keep particles in suspension and the velocity to pick them out.

A

The velocity needed to maintain particles in suspension is less than the velocity needed to pick them up.