Water on the Land - River Processes and Landforms Flashcards
Fill in the blanks.
The ________ is where the river starts. A tributary is a smaller river _______________________, and the ________ of two rivers is a confluence. Where the river ends is called the _________. The drainage basin is the _______________________, and the watershed is the _____________ between two river basins.
- source.
- joining a bigger river.
- junction.
- mouth.
- area of land drained by a river.
- dividing line.
Describe the width and depth of the channels in the upper, middle and lower courses of the river.
- Upper - narrow, shallow channel.
- Middle - wider, deeper channel.
- Lower - widest, deepest channel.
Describe the shapes of the valleys in the upper, middle and lower courses of the river.
- Upper - V-shaped.
- Middle - U-shaped.
- Lower - Flat.
What type of erosion occurs at the upper, middle and lower courses of the river?
- Upper - vertical erosion.
- Middle - some vertical eroson, but mainly lateral erosion.
- Lower - a little lateral erosion.
What processes of transportation occur in the upper, middle and lower course?
- Upper - traction and saltation at high flow.
- Middle - suspension mainly, but saltation and traction is still present.
- Lower - supsension.
What processes of erosion occur at the upper, middle and lower courses?
- Upper - hydraulic action, abrasion, attrition.
- Middle - hydraulic action (becoming less important).
- Lower - all erosion is less important.
NB. solution occurs at anytime.
How does the load size and particle size change in the upper, middle and lower courses?
- Upper - large, angular bed load (particle size), but small load size.
- Middle - particle size is reduced, but increased load size.
- Lower - particle size is very small, but large amount of load.
What is the definition of:
- infiltration
- percolation
- water table
- groundwater
- throughflow
- impermeable
- movement of water into the soil.
- movement of water into the underlying rocks.
- the level at which saturation occurs in the ground.
- water that flows or collects beneath the Earth’s surface, similar to percolation.
- the movement of wayer within the soil sideways, towards the river.
- not allowing liquid to pass through.
Name 6 landforms of the upper course and give their definitions.
- v-shaped valley - a river valley that is steep-sided and narrow and shaped like a ‘v’.
- interlocking spurs - ridges of highland that overlap.
- potholes - circular dips in a river bed.
- rapids - area of faster flowing shallow water with many boulders, leading to turbulent white water.
- waterfall - landform where the river drops vertically.
- gorge of recession - steep-sided narrow valley, created by a waterfall.
Explain 3 steps for the formation of a waterfall.
- Waterfalls are formed when a band of hard rock overlies a softer rock. The soft rock is less resistant and is eroded away quickly, causing undercutting of the soft rock, by hydraulic action.
- The hard rock overhangs until it collapses, adding large blocks of rocks at the base. The power of the waterfall moves the rocks around, eroding the base into a plunge pool, by abrasion and hydraulic action.
- Over a long period of time, this continuously happens, causing the waterfall to retreat. A gorge of recession is formed.
How are meanders created?
- gradient of the land becomes less steep, so vertical erosion becomes lateral erosion.
- to use up surplus energy, the river meanders.
- lateral erosion causes the river to erode the interlocking spurs which makes the valley wider.
Fill in the blanks.
On the outside of the meander, there is the __________ flow and the water level is __________. The force of the water erodes and __________ the outside bend by __________, forming river __________. ___________ action also occurs.
On the inside of the meander, there is the __________ flow and the water level is ____________. Due to less _________, ___________ occurs, therefore sand and pebbles are deposited to form a _________________.
- fastest.
- deeper.
- undercuts.
- abrasion.
- cliffs.
- hydraulic.
- slower.
- shallower.
- energy.
- deposition.
- slip-off slope.
How does the eroded material from the river cliffs get to the slip-off slopes.
An underwater current spirals down the river, carrying the eroded material from the river cliff to the slip-off slope.
What does thalweg mean?
Fastest flow of the river.
Why does the velocity of the water increase in the lower course of the river?
There is less friction in the channel to slow the water down, as the bed is smooth with deposits of mud and sand.
