Water on the Land Flashcards
Draw an label a diagram of the hydrological cycle
Define precipitation
Water that falls on the Earth’s surface
Define groundwater
Water that has sunk through the soil onto the rocks below
Define transpiration
Plants absorb water through their roots and then give off water vapour through the pores in their leaves
Define surface run-off
The movement of water over the land
Define ‘mouth’ (of a river)
Where the river flows into the sea or sometimes a lake/other body of water
Define watershed
The boundary dividing one drainage basin from another - usually a high ridge of land
What is a tributary?
A smaller river which joins a larger river channel
What is catchment?
The area from which water drains into a particular drainage basin
What is the source?
The upland area where the river begins
What is a confluence?
The point at which two rivers join
What is a drainage basin?
An area of land drained by a single river
What is the long profile?
The entire length of the river from its mouth to source
What is the cross profile?
A cut-though or cross-section of a river at any one point.
In the upper course, it’s a steep V-shaped valley with a narrow, shallow river.
In the middle course, it’s less steep-sided with a wider floodplain + river.
In the lower course, it’s a very flat floodplain with a very wide river channel.
Draw and label a diagram of the long profile
Draw and label a diagram of the changing cross profile.
In the upper course there is more vertical erosion, which creates a narrow, deep channel.
In the middle course, there is more lateral erosion, which begins to widen the channel
In the lower course, there is even more lateral erosion, which creates an even wider channel.
What are the features of the upper course?
- Narrow + deep river channels - 1.5m wide in places
- Large, angular bedload
- Steep V-shaped valleys
- Waterfalls + rapids
- Vertical erosion
Processes:
- Traction + saltation
What are the features of the middle course?
- Wider but deep river channels - 5-15m in some places
- Small, angular bedload
- Meanders + Oxbow Lakes
Processes:
- Lateral + vertical erosion
- Suspention, solution, deposition
Describe how waterfalls form.
- Hard rocks lies over soft rock. The soft rock is eroded by hyrdaulic action and abrasion.
- The hard rock is undercut and a plunge pool is created.
- The hard rock is unsupported and collapses. The fallen rock and debris also helps to create a plunge pool as they speed up erosion by falling into the water.
- The waterfall retreates upstream and a gorge is formed.
Describe how a meander forms.
- A meander is a bend in the river.
- Water travels at a higher velocity towards the outside of the bend.
- Erosion (hydraulic action and abrasion) creates a river cliff.
- Water travels at a slower velocity in the inside of the bend.
- This means that deposition occurs, creating a slip off slope.
Describe how oxbows lakes are formed.
- In a meander, the fast flowing water erodes the outside bank, causing it to migrate across the floodplain.
- The river becomes more and more sinuous, cauing the neck to become narrower.
- During a flood event, the river jumps across its neck, leaving the oxbow lake on the floodplain. Due to fact that the water is stagnant, eventually the water will evaportate and the lake will dry up, leaving a meander scar.
Describe the formation of levees.
- When the river floods, the water moves across the floodplain.
- The heavier, coarse sediment is deposited first, followed by smaller sediment and the finest silts last.
- Banks of deposited sediment build up either side of the river.
- More floods result in the banks building up more and more (becoming larger)
- These banks are calles levees.
Describe the formation of floodplains
- Floodplains are created when the river floods.
- The river bursts its banks and deposits alluvium (silt) onto the land.
- Over times, after many floods, this builds up to create an a wide, flat area of land known as a floodplain.
Draw and label a storm hydrograph
