Rivers Flashcards
What shape of land do you get near the source of a river.
A v-shaped valley
What shape of land do you get in the middle course
a u-shaped valley
Where does the river begin
the hills and mountains
Where is the river at its narrowest
the upper course
Where is the river at its fastest
the lower course
Where is the at highest altitude
the upper course
Where does most of the erosion and transportation take place.
The upper course
Where is the river is wider
The middle course
Where does the river get closer to the sea level
The middle course
Where does the river speed up
the middle course
here would you find oxbow lakes
The middle course
The river is at sea level
the lower course
The river is at its widest
the lower course
The river reaches the sea
the lower course
The river deposits the remaining sediment.
the lower course
What are the four types of erosion
hydraulic action, abrasion, attrition and solution.
What is Hydraulic action
The sheer force of water hitting the beds and banks of the river.
What is abrasion
When particles rub against the river bed in sandpaper effect
What is attrition
when the particle bump into each other and become smoother and rounder.
What is solution/corrosion (erosion)
when chemicals in the water break down the particles.
What are the three types of weathering
Biological, chemical and physical
What is physical weathering
When water seeps into a rock freezes and leaves a crack. this happens until the rock is split in half.
What is biological weathering
when tree roots crack rocks.
What is chemical weathering
When chemicals in rain break down the rock.
Is limestone soft or hard rock
soft
Is granite soft or hard rock
hard
Name the four types of transportation
traction, saltation, suspension and solution
What is traction
When large rocks or boulders are rolled along the river bed.
What is saltation
When small rocks are bounced along the river bed.
What is suspension
When pebbles are carried by the current
What is saltation (transportation)
When dissolved particles are carried along by the current.
What is a drainage basin
the are of land which a river drains
What is the water shed
The divide line between river basins
What is a tributary
a smaller river which feeds into a larger river
What is a confluence
Where the smaller river joins the larger one
What is deposition
When material or load is deposited or dropped off due to the river losing energy
What do you call the bottom of a a water fall
a plunge pool
How does a water fall occur
You have hard rock on top of soft rock and the water erodes the soft rock creating overhang through hydraulic action and abrasion, making an overhang and a plunge pool. The over hang collapses and an undercut occurs. the water retreats and a gorge is created when through hydraulic action.
How does a rapid occur?
There would be soft rock surrounding hard rock, and through hydraulic action the soft rock erodes through hydraulic action, but the hard rock doesn’t so the water crashes into the hard rock making rapids
How does an oxbow lake occur
You start with a meander and when the bend is to narrow the river will take the shorter route and cut off the meander, depositing the load and forming an ox bow lake.
What are Meanders
the inner bend has less energy and deposits some load, on the inner bend, which creates a beach. On the outer bend there is erosion as the water has more energy, which creates a river cliff with an undercut similar to a waterfall.
Where does a floodplain occur
the lower course
What benefits to floodplains have
agriculture, easy to build on and minerals are deposited.
What are floodplains
Areas that are flat and have very fertile soil.
Where do levees occur
the lower course
How are levees
When the river floods, load is deposited creating a hill around the river. A man made example would be an embankment.
Where would you find a delta
the lower course
Where would you find an estuary
the lower course
What is an estuary
The place where the river meets the sea
What are the three different types of sources
glaciers, precipitation and springs.
Where can the mouth of a river be
a lake, a larger river or the sea.
What is precipitation
Rain, snow or hail
What is condensation
When water vapour turns into liquid creating clouds
What is evaporation
When the sun turns liquid into vapour
sublimation
When vapour turns straight into ice
What is the difference between erosion and weathering
Erosion is when the rock is in motion whereas weathering is when the rock is stationary
What is a levee
a ridge of sediment deposited naturally alongside a river by overflowing water.
