As a river moves from source to the sea, it carries or transports its load. The load is transported in a number of ways by the river. z„
Large pebbles and stones are rolled and dragged along the river bed by the force of the water. This method is known as traction.
z„ z„ z„
Small pebbles are bounced along the river bed. This method is known as saltation.
Tiny particles are held in suspension in the water – the movement of water is fast enough to keep them from dropping to the river bed.
Dissolved minerals like limestone is carried in solution – it cannot be seen.
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(Traction)
Large stones rolled at high flow
Rolling
Suspension
Bouncing (Saltation)
The hopping motion of pebbles
Solution
Small particles held up within the water
Methods of river load transport River Deposition
Rivers deposit or drop their load when they begin to slow down and lose energy. This happens:
z„ z„ z„
when a river reaches flat ground when a river enters a lake or the sea
at the inside bend of a meander (which we will look at in more detail later in this chapter)
1. What three processes occur in a river to change the landscape? 2. Explain hydraulic action. 3. What is abrasion? 4. Give two reasons why a river may deposit its load.
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Rocks that have been dissolved into the water by weak acids
From smallest to largest particle size, put in order the ways a river transports its load and explain each.
Managing information and thinking:
(i) Solution, (ii) Bouncing, (iii) Rolling, (iv) Suspension.
