Rivers Flashcards
Precipitation
Water falling from the clouds. eg - rain, hail, snow.
Evaporation
the water from the ocean turns into a gas and goes up into the air.
Condensation
The gas turns back into water as a small droplet which form a white, grey or black cloud.
Surface runoff
When the rain, snow or hail runs down back into the source of water.
Ground water
The rain, snow or hail is absorbed by plants and goes through the ground back to the source of water.
Transpiration
When water is taken from plants during evaporation.
Stage 1 of water fall
- Hard and soft rock
River process (4 processes) Erosion
- Hydraulic action (force to move the rocks)
- Abrasion (Sandpaper across the bed and banks of the river)
- Attrition (2 rocks collide into pebbles)
- Dissolve (turns into solution and joins the river flow).
Traction (transport)
When the bolder (rocks) roll across the bed or the river and hit against each other.
Salutation (transport)
The Rocks/pebbles bounce across the river and collide.
Suspension (transport)
The tiny rocks float along the river.
Solution (transport)
The rocks dissolve and become minerals in the river.
Drainage basin
The area where rain falls into.
Source
Where the water comes from.
Tributaries
The break off from the channel.
Confluence
The merge between two rives in one river.
Mouth
Where the river ends to the sea.
Stage 2 of waterfall
- Soft rock erodes
Stage 3 of waterfall
- Notch develops
Stage 4 of waterfall
- Erosion (hydraulic action/abrasion
Stage 5 of waterfall
- Plunge pool
Stage 6 of waterfall
- No support for the hard rock
Stage 7 of waterfall
- Hard rock collapses
Stage 8 of waterfall
- The process repeats
Stage 9 of waterfall
- Gorge in formed.
Meanders
The river isn’t straight but curved along
Fast water where?
Meander
Water flows fast on the outer band of the river
Slow water where?
Meander
Water flows fast on the inner band of the river
Where will the bank erode? (Meander)
The outer bank will erode and get worn away
What shape does the meander turn into over time?
A loop shape
What is an oxbow lake?
A lake that makes a loop then restarts the process (the continuation of a meander
Stage 1 of an oxbow l
The meander starts to bend as the water erodes faster on the outside.
Stage 2 of an oxbow l
As the erosion happens on the outer part of the river, the inner part collects deposited materials.
Stage 3 of an oxbow l
The erosion becomes a meander.
Stage 4 of an oxbow l
The meander erodes more and becomes a tight loop.
Stage 5 of an oxbow l
The meander become a full loop.
Stage 6 of an oxbow l
The river will have enough power to skip the oxbow and go straight through.
Stage 7 of an oxbow l
The river keeps going to its new channel, so the loop is left as an oxbow lake.
Stage 8 of an oxbow l
After a long time, the oxbow lake will dry out and plants will grow in it leaving a meander scar.
Why do river floor?
Deforestation, climate change, precipitation, urbanization
Deforestation (Floods)
No interception = the trees don’t get waster so it will just go straight to the river. This increases the chance of flooding as the water level will rise. Human cause
What of the definition of intercept
Intercept is when the trees stop the water from going straight to the river as they will absorb some of the water.
Urbanization (Floods)
Urbanization is when towns/cities are built. they have drainage and sewers that lead straight to rivers, increasing the chance of flooding. human cause.
What is hard engineering?
When something expensive is man made.
What is soft engineering?
When you use cheaper natural things.
Hard engineering examples (4)
- Dams
- Storage areas
- Deepen meanders
- Embankments
Soft engineering examples (3)
- Wash lands
- Afforestation
- land-use zoning
Embankments definition
These raise the river banks making the river deeper/taller.
Dams definition
These help to hold water as storage to reduce the amount of water and people have control over it.
Wash land definition
This is when no one lives there and it’s just a place of nature and its allowed to flood. People cannot live or build there.
Afforestation
This is when we plant more trees for interception.
