Top 3 - River Landscapes Flashcards
Describe the cross profile of a river lower course.
Very wide
Almost flat valley
Very wide
Deep channel
Name the part of the river course where vertical erosion is dominant
Vertical erosion is dominant in the upper course
What’s the difference between abrasion and attrition?
In abrasion the rocks from the bottom get picked up by current and rub against the channel side and wear it away. In attrition the eroded rocks smash into each other and split and the continues on and on down stream.
When does deposition occur ?
Deposition occurs when the river loses its velocity.
Where do waterfalls form?
Waterfalls form where a river flows over an area of hard rock followed by an area of softer rock.
How is a gorge formed?
The hard rock is eventually undercut by erosion. It becomes unsupported and collapses. Over time more undercutting causes more collapses the water fall will retreat. Leaving a steep sided gorge.
What are interlocking spurs?
interlocking spurs are when in the upper course the stream erodes vertically but not laterally so it ends up having to go around the hard rock.
What is a flood plain?
A flood plain is the wide valley on either side of a river which occasionally gets flooded.
Give two pieces of map evidence for a waterfall.
The actually mark of “waterfall” and black blocky lines in the upper course.
What is river discharge?
River discharge is the volume of water that flows per second.
What is lag time?
Lag time is the time between when the rain falls to when it actually reaches a channel of water.
List two physical factors that can cause floods.
Heavy Rainfall
Prolonged Rainfall
Describe the disadvantages of flood warnings.
Warnings won’t stop the flood from happening
People may not hear or have access to flood warnings
Describe the advantages of river restoration.
There is less risk of flooding downstream because discharge is reduced. Little maintenance is needed.
