Rivers Flashcards
What does latitude effect?
Temperature
What does longitude effect?
Time
Define ‘relief ’
The height and shape of the earth’s surface
What does the GCSEA stand for?
General
Comment
Specific
Example
Anomaly
What is the gradient?
Steepness/shape
What does a large scale map show?
A large scale map shows lots of detail but not much area e.g map of Droylsden
What does a small scale map show?
A small scale map shows a lot of area but not much detail e.g world map
What is a drainage basin?
An area of land drained by a river and its tributaries
What is weathering?
When rock is broken down in a situ (one place)
What is mechanical weathering?
Breaking down of larger rocks into smaller rocks without a chemical change taking place
What is the United Kingdom make up of?
England, Scotland, Wales and Northern Ireland
What are lines of latitude?
Lines of latitude are lines that goes around the equator from east to west
What are lines of longitude?
Lines of longitude are lines that runs from north to south
What is chemical weathering?
A chemical reaction occurs in the rock causing it to dissolve and form new substance e.g limestone dissolved by rainwater (acid rain)
What is biological weathering?
Disintegration of rock due to the actions of plants and animal e.g tree roots and burrowing rabbits
What is the source of a river?
Where the river starts
What is a tributary?
A small stream or river that joins a larger river
What is a confluence?
The point where two rivers meet
What is a watershed?
Higher areas of land at the edge of the river basin
What is the channel of the river?
The part of the river in which the water flows
What is the mouth of a river?
Where the river meets the sea
What is freeze-thaw weathering?
Describe the process
Water getting into a rock
Water freezes
Expand the crack in the rock
Rock breaks off
Puts pressure on the rock
What is erosion?
The wearing away and removal of material by a moving force such as a wave/ flow of a river
What does vertical erosion affect?
River bed
(Makes it deeper)
What does lateral erosion affect?
Banks
(Makes it wider)
What is attrition?
Rocks being carried by the river smash together and break into smaller, smoother and rounder particles
What is abrasion?
Rocks carried along by the river wear down the bed and banks of the river
What is hydraulic action?
The force of the river against the banks can cause air to be trapped in crack. The pressure weakens the banks and gradually wears away.
What is solution in erosion?
Soluble particles are dissolved into the river
What is transportation?
The movement of eroded material
What is traction?
The rolling of boulders along the riverbed
What is saltation?
Particles bouncing along the riverbed
What is suspension?
Fine solid material held in the water
What is solution in transportation?
Soluble particles are dissolved into the river
What is velocity?
The speed of the water
Why does a river deposit materials?
Speed of a river decreases
Not enough energy to carry the material
What does the long profile show of a river?
the gradient of a river on its journey from source to mouth
What is deposition?
When the materials being transported by the river are dropped due to the river losing energy
What is the cross profile of a river?
A section taken sideways across a river channel or a valley
What is the long profile gradient change from upper course to lower course?
Upper course-steep
Middle-medium
Lower-gentle
What is the cross profile valley and channel shape change from upper course to lower course?
Upper course = v-shaped valley , steep sides , narrow , shallow channel
Middle course = gentle sloping valley sides , wider , deeper channel
Lower course course = very wide , almost flat valley sides , deep channel
What is vertical erosion?
Deepens valley and channel making it v-shaped (high turbulence , scraps rocks along bed)
Dominant in upper course
High turbulence
What is lateral erosion?
Widen river valley and channel during formation of meander
Dominant in the middle and upper course
What is the equation for discharge?
Discharge =velocity x cross-sectional area
What is an interlocking spur?
Series of ridges that project out on alternate sides of the valley and around which a river winds its course
What are the characteristics of an interlocking spur?
Steep gradient
Separated by a narrow river channel
Project from alternate sides of the valley
Could have a scree slope at the bottom
How is an interlocking spur formed?
In the upper course of a river there is a low volume of water. This means that the river only has enough energy to erode vertically. This creates a valley with steep sides. The valley also gets wider and steeper due to freeze-thaw weathering.
Rocks in the upper course is often hard, however some of the rocks is more resistant to erode than others.
To save energy the river takes the most efficient route and erodes the least resistant rock. This results in a river which winds its way around interlocking spurs.
What is a waterfall?
A sudden descent of a river or steam over a vertical slope. It often occurs where a river meets a band of softer rock after flowing over the resistant harder rock.
What is a gorge?
A narrow steep sided valley which often forms as a waterfall retreats
What are the characteristics of a waterfall?
Vertical drop
Usually from a height
Deep plunge pool
Horizontal bands of hard and soft rock
What are the characteristics of a gorge?
Very narrow
Steep sides
Located downstream of a waterfall
River channel takes up most , if not all , of the river valley floor
State three upper course landforms
Waterfall
Gorge
Interlocking spur
What is discharge in a river?
Volume of water passing through a appoint given point on the river - measured in a cubic metres per second
How is a waterfall and gorge formed?
A waterfall forms when a layer of hard rock overlies a layer of soft rock. The water erodes the soft rock first because it is less resistant than the hard rock. Creating a steep gradient.
The soft rock is undercut by erosional processes such as hydraulic action and abrasion creating a plunge pool. As the rock is undercut, the hard rock hangs over the edge creating an overhang.
The hard rock overhanging the plunge pool eventually collapses as its weight is no longer supported. These rocks continue to widen and deepen the plunge pool through abrasion.
This process repeats overtime and the waterfall retreats upstream leaving behind a gorge.
What is a mender?
A bend in the course of a river (lateral erosion on the outer bank)
What are the characteristics of a meander?
Slip-off slope (inner bend of a river)
Deposition happens because the flow of the river is slow, so river looses energy and drops the material
River cliff (outer bend of a river) erosional processes rakes place such as abrasion and hydraulic action. There is a faster flow on the outer bend of the river because the river gains energy.
Name the 4 river processes
Weathering
Erosion
Deposition
Transportation
Name the 4 types of the erosions
Hydraulic action
Abrasion
Attrition
Solution
Name the 4 types of transportation
Solution
Saltation
Traction
Suspension
Name the parts that make up the drainage basin
Watershed
Mouth
Channel
Confluence
Tributary
Source
Name three erosional landforms
Interlocking spur
Waterfall
Gorge
Name two erosional and depositional landforms
Meander
Ox-bow lake
Name two depositional landforms
Floodplains
Levees
What is a floodplain?
A large area of flat land on either sides of a river that is prone to flooding
What are the characteristics of a floodplain?
Wide and flat due to meander migrations
Fertile soil due to the build up of slit and alluvium
State 2 middle course landforms
Meander
Ox-bow lake
State 3 lower course landforms
Estuary
Floodplain
Levee
What is the formation of a floodplain?
When rivers flood the velocity of water slows. As a result of this, the river’s ability to transport material is reduced and deposition occurs. This deposition leaves a layer of slit and alluvium on the floodplain. In the subsequent floods more material is deposited and the floodplain builds up. This process repeats over hundreds of years with each flood making the floodplain a little higher.
What is a levee?
Naturally raised river banks on either or both sides of a river channel that often floods
What are the Characteristics of a levee?
Raised river banks (2-8 metres high)
Made from gravel and stone and alluvium
Largest/coarsest sediments is closest to the river channel
Steeper on the channel side
Flat top are often covered in grass
What is an ox-bow lake?
Horse shoe shaped lake which is left behind when a meander gets cut off, normally when it floods
How is an ox-bow lake formed?
An oxbow lake is formed when a meandering river or stream erodes the outer banks of a bend, while the inner banks are deposited with sediment. Over time, this erosion and deposition cause the bend to become more pronounced, until the neck of the meander narrows and eventually breaks through during a flood.
How is a levee formed?
Levees are formed by the repeated flooding. The water will overflow from the river channel onto the surrounding land (flood plain). The large material will be deposited first next to the channel as speed/energy is lost. The smaller materials will be carried further.
What is an estuary?
An estuary is the tidal part of a river where freshwater from the river merges with saltwater from the sea
What are the characteristics of an estuary?
High tidal range
Very wide
Have mudflats which are visible at low tide
Some mudflats may become salt marshes
What is brackish water?
Water that is somewhat salty
In which course of the river does the water flow the fastest?
Lower course
In which course of the river does the water flow the slowest and why?
Upper course because there is more friction
What will the mudflats become overtime?
An eco-system which is colonised by plants that can tolerate high salt conditions
What does the drainage basin hydrological cycle explain?
Explains how precipitation falling in a catchment area gets into a river
What is the water table?
Is the current upper level of saturated rock/soil where no more water can be absorbed
What is prolonged periods of rainfall?
It is the continuous heavy rainfall which may be caused by depression passing over the up, especially in the winter
How does prolonged periods of rainfall increase the risk of flooding?
The ground may become saturated and the soil can no longer store the water, this means that surface runoff may increase , resulting in the higher discharge and therefore more floods
What is heavy rainfall?
Sudden bursts of heavy rainfall over a short period of time
How does heavy rainfall increase the risk of flooding?
Rainfall will infiltrate into the soil but only to a point as the water table will rise. Eventually, the soil may become saturated and cannot hold anymore water. This results in more surface run off which rapidly increases the amount of river discharge. (Flash flood)
What is snow melt?
Sudden snow melt, particularly in mountainous areas
How does a snowmelt increase the risk of flooding?
Snowmelt increases the amount of water in the drainage basin. This excess water will head over land (surface runoff) at a quick rate due to the steepness of the slopes. This increases the amount of river discharge.
What is relief?
The height of the slope ; both areas with steep slopes and areas with flat floodplains that are likely to flood.
What is geology?
The type of rock that can impact on the risk of flooding ; areas with more permeable rocks are less likely to flood
How does relief increase the risk of flooding?
Steep slopes encourages flooding as surface run off happens quickly also flat land can encourage flooding as floodwater is static and does not move anywhere (e.g towards a river)
How does geology increase the risk of flooding?
Impermeable rock makes flooding more likely as infiltration and percolation cannot happen. This means more water on the surface which will run off towards the river and increase discharge
What is precipitation?
Any source of moisture reaching the ground, e.g rain , sleet or snow
What is evaporation?
water lost from ground / vegetation surface. The process of water turning into water vapour
What is transpiration?
water lost through pores in vegetation
What is interception?
water being prevented from reaching the surface by the Rees or grass
What is surface storage?
water held on the ground surface , e.g puddles
What is soil moisture?
water held in the soil layer
What is groundwater?
water stored in the rock
What is infiltration?
water sinking into the soil/rock from the ground surface
What is percolation?
water seeping deeper below the surface
What is surface runoff?
water flowing on top of the ground
What is through flow?
water flowing though the soil layer parallel to the surface
What is ground flow?
water flowing in the rock layer parallel to the surface
What does the flood hydro-graph?
Shows how a river’s discharge changes in response to precipitation event
What is river discharge?
volume of water flowing through a river channel
What is lag time?
the time difference between the peak rainfall and peak discharge
What is base-flow?
The normal amount of flow of a river
What is peak rainfall?
Highest amount amount of rainfall
What is the rising limb?
how quickly the water reaches the river
What falling limb?
reduced discharge once the main effect of runoff has passed
State where the River Tee is located
Eastern slope of Cross Fell in the North Pennines and lows eastwards for 85 miles to reach the North Sea in the North east of England
River Tees: high force waterfall
21 metres high
Upper course
Hard rock called whin sill (or whinstone)
Soft rock (sandstone and shale)
River Tees: estuary
The River Tees has a very large estuary with mudflats and sandbanks, which supports wildlife in the area. Sites such as Seal Sand are protected ares
River Tees : meander (Middle course -Banards Castle)
River tees starts to erode sideways, it forms meanders . These can be identified in the middle course near barnyard castle.
River Tees : near Yarm (lower-course) ox-bow lakes
Near Yarm, the meander in the lower course are much larger, and have formed. In this area there also which have formed when river has flooded
