rivers Flashcards
name the four main proccesses of erosion [4]
-hydrolic action
-attrition
-solution
-abrasion
name the four main proccesses of transportation [4]
-suspension
-solution
-saltation
-traction
hydrolic action [1]
the force of water on the bed and banks of a river removes material
attrition [1]
the load that is carried by the river bumps together and wears down into smaller smoother pieces
abrasion [1]
material carried by the river rubs against the bed and banks and wears them away
solution [1]
some rock minerals dissolve in river water (e.g. calcium carbonate in limestone)
traction [1]
large boulders roll along the river bed
saltation [1]
smaller pebbles are bounced along the river bed, picked up and then dropped as the flow of the river changes
suspension [1]
finer sand and silt particles are carried along in the flow, giving the river a brown appearence
solution [1]
minerals from rocks such as limestone and chalk are dissolved in the water and carried along in the flow, although they cannot be seen
name the three types of weathering [3]
-chemical
-physical
-biological
Explain how both the processes of erosion and deposition create river meanders. [4]
Firstly, meanders form as lateral erosion naturally makes the outside bend of the river faster, meaning it gets more curvy through erosion, such as Hydraulic Action.
Secondly, a meander continues to form as the inside bend is slower, causing deposition, this also enhances the rivers curve.
Explain two differences between upper course and lower course river landscapes. [4]
-The upper course landscape is narrower and steeper, because of vertical erosion, making landforms such as Waterfalls.
-The lower course landscape is often used for agriculture, such as farming, this is due to the presence of floodplains making the land more fertile.
list the causes of flooding (human) [4]
- impermeable roads
-built up areas
-building on floodplains
-loss of trees due to deforestation
list the causes of flooding (physical) [4]
-heavy/prolonged rainfall
-impermeable rock (e.g. granite)
-tributaries running into river
-snowmelt
explain what river proccesses occur at the upper course of a river [2]
the river is fast flowing and eroding downwards and very quickly
explain what river proccesses occur at the lower course of a river [2]
here there is high discharge and some deposition and erosion, though the erosion is reduced, due to the slowed flow of the river.
explain what river proccesses occur at the middle course of a river [2]
lateral erosion becomes more significant, often creating meanders, and as the river slows down and loses some energy, deposition begins to occur
the water cycle is a ____ system
closed
Evaporation
liquid to gas
