UK physical landscapes : River Landscapes in the UK Flashcards
Define abrasion
rocks carried along by river, wearing down bed and banks
Define attrition
rocks carried along by river, smashing together into smaller, rounder pieces
Define discharge
quantity of water passing point within time period
Define estuary
tidal mouth of river where it meets sea
Define gorge
narrow, steep sided valley
Define hydraulic action
force of river against banks cause air to be trapped in cracks and crevices
Define interlocking spurs
series of ridges on alternate sides of valley around river
Define lateral erosion
sideways erosion by river on outside meander channel
Define meander
pronounced bend in river
Define ox bow lake
arc shaped lake cut off from meandering river
Define precipitation
moisture falling from atmosphere
Define traction
rolling of boulders and pebbles along river bed
Define vertical erosion
downward erosion of river bed
Define waterfall
sudden descent of river over vertical slope
On a global cycle the hydrological cycle is…
…a closed system
What does a closed system mean?
nothing can leave or enter system
On a local scale, the hydrological cycle is…
…open system
What does an open system mean?
inputs and outputs
What is a water table?
current upper level of saturate rock where no more water can be absorbed
What is ground water flow?
water flowing through rock layer parallel to surface
What is through flow?
water flowing through soil layer parallel to surface
What is surface run off?
water flowing on top of the groun
What is evaporation?
water lost from ground / vegetation surface
What is transpiraiton?
water lost through pores in vegetation
What is groundwater storage?
water stored in rock
What is percolation?
water seeping deeper through rock
What is infiltration?
water sinking into soil/rock from ground surface
What is surface storage?
water held on ground surface
What is interception?
water prevented from reaching surface/ground by trees
What is precipitation?
source of moisture reaching ground
How does deforestation affect surface run off?
increases speed, less interception
How does urbanisation affect ground water?
water cannot be stored, flooding
What is the source?
start of river
What is the drainage basin?
area of land drained by river and tributaries
What is confluence?
where tributary joins to bigger river
What is mouth?
end of river
What is watershed?
edge of river basin
What is tributary?
small stream that joins a larger river
How might the characteristics of a drainage basin vary?
size
relief
geology
land use
How many courses of a river are there?
3 courses
What are the three courses of a river?
upper
middle
lower
How does the long profile of a river change from source to mouth?
gradient decreases
What is the river valley like in the upper course?
steep
v shaped
What is the river valley like in the middle course?
shallow
What is the river valley like in the lower course?
flat
What is the river channel like in the upper course?
waterfalls
What is the river channel like in the middle course?
wider
deeper
meanders
What is the river channel like in the lower course?
widest
deepest
most meanders
Which landforms occur in the upper course?
interlocking spurs
Which landforms occur in the middle course?
meander
ox bow lake
Which landforms occur in the lower course?
flood plain
levees
estuary
Give examples of fluvial processes
erosion
transportation
deposition
Define erosion
wearing away of material
Where is the process of erosion most dominant?
upper course
How does erosion occur in the upper course of the river?
vertically
Why does erosion occur vertically in the upper course?
discharge smallest
rive cutting down to get to sea
rock is most resistant
How does erosion occur in the middle course of the river?
laterally
Why does erosion occur laterally in the middle course of the river?
material carried by river erodes banks
What processes occur in the middle course?
deposition
transportation
erosion
Where is deposition most dominant?
lower course
Why is deposition the most dominant in the lower course?
losing energy
What does vertical erosion mean?
deeper
What does lateral erosion mean?
wider
Define solution
occurs when water is slightly acidic - dissolves rock
What are the four processes of erosion?
hydraulic action
attrition
abrasion
solution
What are the four processes of transportation?
traction
saltation
suspension
solution
What is the load?
materials carried by river
How does discharge effect load?
discharge - more or less load
Define saltation
small rocks and particles bounce along river bed
Define suspension
fine clay and particles carried along
Define solution
minerals dissolve in water - requires little energy
What part of load is dropped first?
heaviest
When does deposition occur?
flooding
meander
mouth
Why does deposition occur when flooding happens?
friction occurs between land - slows river
Why does deposition occur at meanders?
loses speed on inside bend
Why does deposition occur at mouth?
slows as it hits large body of water
Which landforms occur in the upper course?
waterfalls
gorges
v shaped valleys
interlocking spurs
Which landforms occur in the middle course?
meanders
ox bow lakes
Which landforms occur in the lower course?
levees
flood plain
estuary
mud flat
Which processes occur in the upper course?
erosion
What is the load like in the upper course?
large
angular
Which processes occur in the middle course?
erosion
transportation
What is the load like in the middle course?
smaller
rounder
Which processes occur in the lower course?
transportation
deposition
What is the load like in the lower course?
small
round
How do interlocking spurs form?
vertical erosion
- steep sided / v shaped
- lack lateral erosion
- wind round hillsides
Water runs over alternating bands of…
…hard and soft rock
Erosion will start to break down through….
…..erosional processes
What does hydraulic action wear away?
soft rock
Why does hydraulic action wear away the soft rock?
less resistant
The soft rocks starts….
….to undercut the hard rock
hard rock is left…
…unsupported
hard rock collapses….
into the river bed
Where does erosion occur when forming a waterfall?
upstream
Why is inside bend slower of a meander?
it is shallower
Why is the inside bend of a meander shallower?
little energy - deposits
What is formed as a result of the deposition?
slip off slope
What are the other names for a slip off slope?
point bar
river beach
Why is the outside bend of a meander faster?
deeper
Why is the outside bend deepr?
faster - high energy - hydraulic action / abrasion
Which physical factors affect flooding?
geology
saturation
rainfall
land relief
basin size
Which human factors affect flooding?
development
climate change
trees
deforestation
agriculture
Define flooding
amount of water exceeds - bursts banks
What are the characteristics of an oxbow lake?
horseshoe shape
narrow channels
cut off
What shape is an oxbow lake?
horseshoe
What is the channel of an oxbow lake like?
narrow
How does an oxbow lake form?
neck of river broken off
What is the first step in the formation of an oxbow lake?
- water flows over land, outside bend of river
What is the second step in the formation of an oxbow lake?
- river erodes the bank
meander occurs
What is the third step in the formation of an oxbow lake?
- flow on inside bend slows and sediment is deposited
What is the fourth step in the formation of an oxbow lake?
- neck of river grows narrower
What is the fifth step in the formation of an oxbow lake?
- neck of river breaks through, river takes shortest route
What is the sixth step in the formation of an oxbow lake?
- lake sealed off due to deposition
Why does an oxbow lake get sealed off?
deposition
Why does the neck of the river break?
river will take shortest route and continue straight
Why is their lots of deposition on the inside bend?
water moving slower
Why does water flow over land and on the outside of the river?
less friction
What are the characteristics of a levee?
vegetation
wide
Why does a levee high fertility?
deposition of minerals
Define levee
raised bank formed on banks of river in lower course
How does a levee form?
when river floods, deposits silt
When does a levee form?
flooding
What part of load is deposited first when forming a levee?
heaviest
What part of load is deposited last when forming a levee?
lightest
Why is the heaviest part of load deposited first when forming a levee?
not enough energy
How does a levee change as flooding becomes more frequent?
levees develop more
How does flooding affect the river?
levees build up
river bed build up
Define flood plain
area around a large river that is covered in times of flood
Describe the characteristics of a flood plain
large
flat
What processes form a floodplain?
deposition
erosion
How does a floodplain form?
build up of sand, silt and clay formation of flat land either side of river
What is the difference between floodplain and levee in terms of characteristics?
levee - raised banks
floodplain - large flat area
What parts of the load form a levee compared to a floodplain?
levee - heaviest
floodplain - lightest
What is a floodplain covered by during the flood?
excess surface water
What shape is an estuary?
fan shaped
Define estuary
where the river meets the sea
What is the location of an estuary?
coastal
How does salinity change down an estuary?
increases
How does the channel of an estuary change?
widens
Why does an estuary channel widen?
increase capacity
Why does salinity increase in an estuary?
meeting sea water
Why is material deposited at an estuary?
sea and river meet
tidal processes begin
slows down / lose energy
What causes material to be deposited in an estuary?
tidal processes begin
How does agriculture affect flooding?
ploughing
cattle farming
How does cattle farming affect flooding?
trampling
reduces infiltration of soil
How does ploughing affect flooding?
directs surface water
How does farming affect flooding?
loss of top soil
-> sedimentation
How does climate change affect flooding?
changes rainfall
increases storms
What does anthropogenic mean?
human induced
How does urbanisation affect flooding?
land useH
How does concrete and tarmac affect flooding?
decreases infiltration
increases surface run off
What affect does decreasing infiltration have?
increases surface run off
What does an increase in surface run off cause?
flooding
How does deforestation affect flooding?
decrease in interception
Why does deforestation cause a decrease in interception?
parched ground (no shade)
Define flooding
amount of water in river exceeds, causing bursting of banks
Define discharge
volume of water flowing through river channel CUMECS
Why does flooding increase due to urbanisation?
impermeable tarmac
Why does flooding increase due to agriculture?
soil left exposed
increase surface run off
Why does flooding increase due to deforestation?
reduced uptake
Why does flooding increase due to geology/rock type?
impermeable
surface run off increases
Why does flooding increase due to basin size?
small - unable to carry water - overflow
Why does flooding increase due to soil saturation?
over saturated
increases surface run off
Why does flooding increase due to relief?
steep - water moves quickly
- more water enters
Why does flooding increase due to precipitation?
flash floods
What is the key factor that leads to flooding?
physical
Which physical factor affect flooding the most?
precipitation
Why does precipitation affect flooding the most?
intensity
duration
frequency
How do human factors exacerbate flood risk?
urbanisation
deforestation
agriculture
What is discharge measured in?
cumecs
m3/s
Name the parts of a hydrograph
falling limb
rising limb
lag time
peak discharge
ground water flow
baseflow
What does a hydrograph show?
relationship between precipitation and discharge
What is the lag time on a hydrograph?
number of hours between peak discharge and peak rainfall
Give the human factors affecting river discharge
urbanisation
agriculture
Give the physical factors affecting river discharge
relief
geology
precipitation
Why do rivers need to be managed?
flooding
erosion
Give examples of hard engineering?
dams
reservoirs
straightening
embankments
flood relief channels
Dams and reservoirs are example of what?
hard engineering
Straightening and embankments are example of what?
hard engineering
Flood relief channels are examples of what?
hard engineering?
What is hard engineering?
building artificial structures to control river
What is soft engineering?
working with environment to control river
Give examples of soft engineering
flood warnings
preparation
flood plain zoning
planting tress
river restoration
Flood warnings and preparation are examples of what?
soft engineering
Flood plain zoning is an example of what?
soft engineering
Planting trees and river restoration are examples of what?
soft engineering
What is a dam?
large concrete barrier built across river to hold back flow
What affect does a dam have on the valley behind it?
valley behind floods and forms a reservoir
How is water released from a dam?
controlled amounts
How does a dam prevent flooding?
water controlled and released in monitored amounts
What are the economic and social benefits of a dam?
hydroelectric power
drinking water
tourism
What are the environmental benefits of a dam?
new wetland habitats
controls discharge
What are the economic disadvantages of a dam?
expensive to make
displacement costs
What are the environmental disadvantages of a dam?
habitats / migration disrupted
reservoir silts up - decreases capacity
What is channel straightening?
meandering section of river is straightened
How does channel straightening change the channel?
widened, straightened, deepened
How does channel straightening prevent flooding?
river carries more water
water moves faster
Where does channel straightening occur?
low lying areas
high risk from flooding
What are the social benefits of channel straightening?
navigation increases
What are the economic benefits of channel straightening?
insurance premiums reduced
What are the economic disadvantages of channel straightening?
expensive to do
maintenance required
What are the social disadvantages of channel straightening?
unattractive and unnatural
What are the environmental disadvantages of channel straightening?
habitats destroyed
increased flooding downstream
What are embankments?
raised river banks
How do embankments reduce flooding?
more water contained inside channel
How is an embankment made?
bulldozers move large mounds of impermeable soil on to river banks
What are the social advantages of embankments?
walkways created
increased capacity
What are the environmental advantages of embankments?
habitats created
What are the economic disadvantages of embankments?
expensive
What are the environmental disadvantages of embankments?
increases severity of flooding if it fails
What are the social disadvantages of embankments?
increases severity of flooding if it fails
unattractive and unnatural
What is a flood relief channel?
another channel built to deliberately move water away from human settlements during times of high discharge
When is a flood relief channel used?
times of high discharge
Where do flood relief channels aim to protect?
human settlements
What are the social and economic benefits of a flood relief channel?
reduced flooding
recreating
insurance premiums reduced
What are the social and economic disadvantages of a flood relief channel?
costly
regular maintenance
habitat destroyed
unattractive and unnatural
What is flood watch?
flooding of low lying land and road expected
What is flood warning?
threat to homes and businesses
What is a severe flood warning?
extreme danger to life and property expected
How should people respond to a flood watch?
prepare and watch river levels
How should people respond to a flood warning?
move valuable items to upper floors and turn off electric and water
How should people respond to a severe flood warning?
leave property
What are the economic disadvantages of flood warning?
monitoring equipment
What are the social disadvantages of flood warnings?
people may not respond appropriately
What are the social benefits of flood warnings?
help people prepare
sustainable
ensures safety
How are flood warnings sustainable?
recognises that flooding is a natural event - people must live with it
What are the economic disadvantages to floodplain zoning?
restricts economic development
How does floodplain zoning restrict economic development?
land uses are prohibited
What are the social disadvantages of floodplain zoning?
hard to implement if urban settlement already developed
housing shortages continue
What are the environmental disadvantages of floodplain zoning?
habitats destroyed
What are the economic advantages of floodplain zoning?
low cost - planning regulations
reduces insurances costs
What are the environmental benefits of floodplain zoning?
reduces impermeable surface coverage
protects water meadows and conserves wildlife
What is tree planting?
afforestation
How does afforestation reduce flooding?
increases interception and uptake
How does floodplain zoning reduce flooding?
restricts land use
How does flood warning reduce flooding?
reduces affects of flooding
How does river restoration reduce flooding?
restores channels to meandering
What are the environmental disadvantages of afforestation?
reduce habitat diversity
increased soil acidity
What are the social and economic disadvantages of afforestation?
loss of farm land
What are the environmental benefits of afforestation?
creates habitats
natural method
absorbs carbon
What are the economic benefits of afforestation?
relatively inexpensive
What are the social and economic disadvantages to river restoration?
expensive to construct and maintain
changes land use
small scale flooding occurs - inconvenience
What are the environmental benefits to river restoration?
recreates natural attractive fluvial environment
restores wetland
increases biodiversity
What counties surrounded the Jubilee River flood-relief channel?
Buckinghamshire
Oxfordshire
Berkshire
Which direction does the Jubilee River flow?
West
What is the source of the Jubilee River?
River Thames
What towns does the Jubilee River flow through?
Maidenhead
Eton
Old Windsor
Wraybury
What was the cost of the Jubilee River?
£110 million
What is the length of the Jubilee River?
11.7 km
What was the cost of repairing the channel after an episode of flooding?
£680,000
Which year was the Jubilee River completed?
2002
What is the width of the Jubilee River?
50m
Which year was the worst for flooding of the Thames since 1947?
2014
How many homes did the Jubilee River protect?
3,200 homes
What does the Jubilee River act as for the River Thames?
relief channel
Give an example of a flood management scheme in the UK
Jubilee River
What is the Jubilee River an example of?
flood relief channel
What type of engineering strategy is the Jubilee River?
hard engineering
What was the business insurance cost in 2014 for Wraysbury?
£500 million
What effect did the increase in insurance costs have on current insurance premiums?
increased the current insurance premiums
How many properties were protected in the affluent areas?
3,000 properties
What are the affluent areas surrounding the Jubilee River?
Eton
Windsor
How many properties were protected in less affluent areas surrounding the Jubilee River?
less than 3,000 properties
What does the Thames now experience due to the merging of the channels upstream?
higher discharge
What causes the Thames to experience higher discharge?
merging of channels upstream
What problem did the merging of the channels upstream lead to?
extreme floods in 2014
List the socioeconomic disadvantages of the Jubilee River
- insurance costs
- affluent properties
- flood relief
List the environmental disadvantages of the Jubilee River
- higher discharge
- algae
- eyesore
Why are the weirs of the Jubilee River an eyesore?
ugly- under normal flow conditions
Why does algae collect behind the weirs of the Jubilee River?
flow of water is stopped / slowed
