River processes and pressures Flashcards
What is the gradient like in the upper course?
Steep
What is the discharge like in the upper course?
Small
What is the depth like in the upper course?
Shallow
What is the channel shape like in the upper course?
Narrow, steep sides
What is the velocity like in the upper course?
Quite fast
What is the valley shape like in the upper course?
Steep sides
What features are found in the upper course?
Waterfalls, interlocking spurs
What is the gradient like in the lower course?
shallow gradient
What is the discharge like in the lower course?
Very large
What is the depth like in the lower course?
Deep
What is the channel shape like in the lower course?
Flat floor, gentle slopping sides
What is the velocity like in the lower course?
Very fast
What is the valley shape like in the lower course?
Flat, gentle slopping sides
What features are found in the lower course?
Meanders, floodplains, levees and ox-bow lakes
What is the gradient like in the middle course?
Less steep
What is the discharge like in the middle course?
Large
What is the depth like in the middle course?
Deeper than the upper course
What is the channel shape like in the middle course?
Flat, steep sides
What is the velocity like in the middle course?
Fast
What is the valley shape like in the middle course?
Flat, steep sides
What features are found in the middle course?
Meanders and floodplains
What are the four main processes of erosion?
Hydraulic action
Abrasion
Attrition
Solution
What is hydraulic action?
The force of water on the bed and banks of the river removes material
What is attrition?
The load that is carried by the river bumps together and wears down into smaller, smoother pieces