Hjulström graph Flashcards
What is competence?
competence is the maximum size of material which a river is capable of transporting.
what is capacity?
the total load actually transported.
What is the pick up curve?
-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.
What is the drop curve?
-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.
What does the Hjulström graph show?
the relationship between velocity and particle size , for example competence.
The graph shows that velocity to require sand is lower than clay. Why is this?
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.
What is the difference between the velocity to keep particles in suspension and the velocity to pick them out.
The velocity needed to maintain particles in suspension is less than the velocity needed to pick them up.
