Rivers and erosion Flashcards
River types, erosion types, floods,
What are the three river courses?
Upper, middle and lower course.
What is a tributary?
a river or stream flowing into a larger river or lake.
What is a floodplain?
An area of flat land alongside a river.
What are levees?
An embankment built to prevent the overflow of a river.
What is a riverbed?
The bed or channel in which a river flows.
Is the channel deep or shallow in the upper course?
Shallow.
Does the water travel faster or slower in the lower course?
Faster.
Is there less or more friction in the lower course than the upper course?
Less friction in the lower course than the upper course.
In which courses does erosion take place the most?
The upper and middle course.
What are the two names for erosion taking place downwards and sideways on the river bed?
Vertical erosion and Lateral erosion.
What is abrasion?
The process where rocks carried by the water scrape and
bang against the sides of the river and wear away the channel gradually.
What is attrition?
Rocks and pebbles hitting against each other, wearing each other down, becoming round and smaller. Attrition reduces the size and shape of the load,
but doesn’t change the shape of the river channel.
What is hydraulic Action?
Water and air under high pressure gets caught and causes cracks to force apart and widen rocks along the riverbank. This causes the rocks to fracture and
collapse into the river, expanding the river channel.
What is corrosion?
The river gradually dissolves chemical compounds in rocks that it flows over. For example, if the river water is acidic limestone dissolves gradually into the river.
