Water on the Land. Flashcards
What does a rivers long profile show?
A rivers long profile shows how a rivers gradient changes as it flows from the source to the mouth.
Describe the cross profile of a river’s lower course.
In the lower course, the river is very wide, almost flat valley and has a very wide, deep channel.
Name the river course where vertical erosion is dominant.
It is dominant in the upper course of a river.
What is the difference between abrasion and attrition?
Abrasion is when eroded ricks picked up by the river scrape and rub against the channel, which wears it away.
Attrition is when eroded rock picked up by the river smash into each other and break into smaller fragments.
Name two processes of transportation.
Traction and Suspension.
When does deposition occur?
When a river drops the eroded material it is transporting, due to the river losing velocity.
Where is the current fastest on a meander?
The outer bend of the meander (Thalweg).
Name the landform created when a meander is cut off by deposition.
Ox-bow lake.
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?
A gorge is formed as over time, more undercutting causes more collapses, so the waterfall will then retreat leaving behind a steep-sided gorge.
What is a flood plain?
A flood plain is the wide valley floor on either side of a river which occasionally gets flooded.
Describe how levees are formed.
During a flood, eroded material is deposited over the whole flood plain. The heaviest material is deposited closest to the river channel, because it gets dropped first when the river slows down. Over time, the deposited material builds up, creating levees along the edges of the channel.
What do the contour lines on a map show?
They tell you about the height of the land (in metres) by the numbers marked on them and the steepness of the land by how close together they are.
Give two pieces of map evidence for a waterfall.
Waterfalls are marked on maps, but the symbol for a cliff (black lines) and the close contour lines are evidence for a waterfall.
Give two pieces of map evidence for a river’s lower course.
The river is wide (A thick blue line).
The river only crosses one contour line so it is very gently sloping.
