1. Traction
- Larger rocks like bigger pebbles and boulders
- Slide along river bed
- Move only if speed of river's great enough to move them
- Some are so heavy they can only be rolled along during heavy flooding

2. Saltation
- When river energy increases
- Coarse sand and other small rock fragments like gravel
- Lifted up briefly then dropped on river bed so they bounce along in a series of "jumps"/"hops" along the river bed

3. Suspension
- Fine particles like fine sand, silt and clay
- Lifted off bed and carried away in water as suspension load
- Suspension loads forms largest part of river load
- Suspension load also responsible for giving water a murky appearance

4. Solution
- Soluble materials in rocks like salts/calcium/sodium dissolve in water and are carried away in solution
- Dissolved materials can't be seen
- Solution can occur even when speed of river and volume of water are low

Deposition:
 A river deposits its load when the volume and speed of water decreases and is carrying a greater load than it can transport.

Heaver materials always deposited first then lighter materials because there is not enough energy to carry the heavy materials (require more energy)

Volume can decrease when:
- little/no rain falls (E.g. dry season)
- river flows across arid area where there's a high rate of evaporation
- river flows across permeable rocks > water sinks in
- flood water brought by storm's drained away

Speed can decrease when:
- sudden change of gradient (E.g. river leaving mountain & entering flat lowland)
- river flows into another body of water like lake/calm sea
- increase in wetted perimeter > more friction (E.g. river overflowing banks and entering flood plain)
- water flowing in shallow section of river (E.g. convex bank of meander) > encounters friction
- obstruction (E.g. mounds of deposits/rock outcrops) make channel rougher > increase friction

a larger drainage basin → a greater volume of water. this is because there is a greater number of tributaries bringing water to the river resulting in a higher surface runoff. 

(b) presence of vegetation cover

thick vegetation cover to intercept rain and allow more water to infiltrate into the soil subsurface and percolate through the underlying soil and rock layers  → less surface runoff  → less water flows into the river  → volume of water would be smaller than that of an area with little or no vegetation

(c) rainfall
higher rainfall → greater volume of flow in a river

(d) temperature
temperature is high  → more evaporation and transpiration  → reduces the amount of water in the river

(e) permeability of rocks
> rocks which allow water to pass either via a network of pore spaces between particles or along bedding planes, cracks and fissures are permeable

water flows through an area of permeable rock → more water infiltrates the ground → low surface runoff → lower volume of flow.

On the other hand, a river flows faster, instead, in a channel made of smooth slits and clays 

If both channels have the same cross-sectional area, the one with the larger wetted perimeter flows slower than that of a small wetted perimeter because of more friction