11.2 Fluvial (River) processes Flashcards
What types of erosion cause the downstream to change?
➢ Vertical erosion
➢ Lateral erosion
What types of erosion landforms are found at the upper course?
➢ Waterfalls
What types of erosion and deposition landforms form at the middle course of the river?
➢ Meanders
What types of landforms will form at the lower course?
➢ Deposition landforms such as levees
What is hydraulic action?
➢ Force of the water hitting the river bed and banks
What is abrasion?
➢ When the load carried by the river repeatedly hits the bed or banks
What is attrition?
➢ When stones carried by the river knock against each other
What is solution?
➢ When the river flows over limestone or chalk - the rock is slowly dissolved
What is suspension?
➢ When the small sediment is held in the river
What is saltation?
➢ Bouncing motion of particles too heavy to be suspended
What is traction?
➢ Large particles rolled on the riverbed
When does deposition take place?
When the velocity of the river decreases
Where are rocks deposited?
➢ Larger rocks tend to be deposited in the upper course of a river - they are only transported for very short distances mostly by traction
➢ Finer sediment is carried further downstream mostly held in suspension
