The UK’s evolving physical landscape Flashcards
what is geology
the study of earth’s physical structure
rocks, ocean, atmosphere etc
how does sedimentary rock form
particles of minerals eroded together to form a new rock
how does igneous rock form
mantle cools and hardens again
how does metamorphic rock form
type of rock that is changed into a new type of rock underground due to intense heat and pressure
give an example of each rock
sedimentary - granite, pumice
igneous - sandstone, coal
metamorphic - slate, marble
where can each type of rock be found
sedimentary - south England ( east Anglia), lowlands
igneous - highlands in Scotland
metamorphic - Scotland, Pennines
why are highland areas located where they are
located mainly in the north and made mostly of metamorphic and igneous rock. These rocks are harder and therefore harder to erode. past glaciers eroded creating u shaped valleys which then creates highlands.
why are lowland areas located where they are
located mainly in the south and made of sedimentary rock which is softer and easier to erode.
what are glaciers
large accumulation of ice, rock, snow and often water that originates on land and moves down under its own wight and gravity
what is the distribution of glaciers in the uk
- north
- Scotland, Northern England
- because they are closer to the artic and further from the equator - less solar radiation
- because it is colder
how do glaciers shape land
erosion, weathering, transportation, deposition
what is pastoral farming
animal grazing
what is arable farming
crop growing - Denby’s vineyard
what is biodiversity
large variety of plants and animals
what is agriculture
the science of farming
what is forestry
developing, cultivating forests
what is settlement
a place where people live
what is a fetch
the distance the wave has to travelled towards the coastline over open water.
long fetch more powerful wave
what are the four types of erosion
- hydraulic action
- abrasion
- solution
- attrition
explain hydraulic action
the force of air and water hitting cliff face wearing it away
explain abrasion
materials carried in the waves rubbing against cliff wearing them away
explain solution
chemical reaction dissolving rocks and minerals eg chalk
explain attrition
the sediment particles carried in the river collide with each other
what are the two types of waves
destructive and constructive
explain the properties of destructive waves
strong backwash
weak swash
destruction of the beach - sucking things back into the sea
waves with steep gradient
short
erodes
explain the properties of constructive waves
weak backwash
strong swash
construction of the beach - materials deposited from swash builds
waves with shallow gradient
long wavelength
doesn’t erode
what is a discordant coastline
layers of rock (hard, soft) are alternately lying perpendicular to the coastline. creates headlands and bays because over time soft rock erodes
what is a concordant coastline
layers of alternating rock lying parallel to the coastline. creates cliffs
what is a wave cut notch and how is it formed
a dent in the cliff
formed by the hightide sea eroding the cliff which is under the water. the cliff then retreats backward and any materials on top of cliff will fall in the sea
what is a wave cut platform and how is it formed
flat area often found at the base of a sea cliff below low tide level
formed by erosion hydraulic and abrasion
how are caves, arches and stacks formed
a headland will erode resulting in a cave. as the cave erodes further it will reach both sides, cutting through the headland. this then creates an arch - rock is still above. eventually this arch will erode through abrasion and hydraulic action. the arch becomes too thin and breaks off from the headland leaving a stump in the middle of the ocean.
what is weathering
the breakdown of rocks
what are the three types of weathering
physical, chemical, biological
explain physical weathering
freeze thaw
- water gets into weaknesses of rocks and this then freezes and expands
- this causes rock to crack even more
- water gets into crack this process repeats and eventually breaks
explain chemical weathering
water reacting to chemicals in the rock causing it to wear away - chalk and water, acid rain
explain biological weathering
roots underground growing into rock, growing and therefore breaking rock
what is mass movement
a sub arial erosion process involving layers of different types of rock. if layers of rock are permeable (water can soak through) causing cliff to slump
what is the longshore drift
the transportation of sand and pebbles along the coast by waves
what is deposition
When the sea loses energy, it drops the sand, rock particles and pebbles it has been carrying
what is footpath erosion called
desire paths
how have humans changed the landscape
tourism (campsites), farming, desire paths
how does climate change cause problems for coastlines
- rising sea levels - caused by temperature increase - ice melts. impacts people becauase erosion, loosing houses, effect economy - loss of jobs/tourism, flooding
where are some areas in the UK that are at risk of costal flooding
- east England
- north west England
what is hard engineering
using artificial structure to control natural processes
what is soft engineering
use environmentally friendly methods to protect the coast
what are examples of hard engineering
sea walls, rock amour, groynes, gabions
what are examples of soft engineering
beach nourishment, dune regeneration, dune fencing
define the watershed
the boundary of drainage basin separating one drainage basin from another and is usually in high land or hills
define the source
the starting point of a stream or river often a spring or lake
define the mouth
the point where a river leaves its drainage basin and flows into the sea
define the confluence
the point where two streams or rivers meet
tributary
a stream or small river that joins a larger stream or river
what are the three processes that occur in rivers
river errosion, transportation, weathering
what are the four types of river erosion
hydraulic action, abrasion, solution, attrition
what are the four types of river transportation
traction
saltation
suspension
solution
what does river transportation lead to
deposition
what are the three types of weathering and give a small piece of info about them
physical - freeze thaw
chemical - acid rain
biological - roots in plants
what are the three landforms in the upper course of the river
waterfalls, gorges and interlocking spurs
what are the two landforms in the middle course of the river
meanders and oxbow lakes
what are the four landforms in the lower course of the river
floodplains, levees, estuaries, deltas
what is the type of erosion in the upper, lower and middle course of the river
upper - vertical
middle - both
lower - lateral
how are waterfalls created
cliff made from hard rock on top and soft rock below. an overhang is created from undercutting of soft rock, the overhang falls because of gravity creating plunge pools. the waterfall then retreats backwards
how are interlocking spurs created
If there are areas of hard rock which are harder to erode, the river will bend around them
what are meanders
a bend in the river
how are meanders created
the fastest flow of water is on the outside of the river causing erosion on those specific areas causing the river to retreat. the slower pathway of water also deposits its load causing the river to never get wider
what are floodplains used for and why
usually grazing as a lot of nutrience is deposited when the areas flood. not used for housing as it will flood
how are oxbow lakes created
the neck between a meander will erode until eventually they join changing the flow of water as it takes the quickest route (not around the loop). deposition occurs where the meander once was causing a seal between oxbow and meander.
what are floodplains
the area either side of a river that floods
what are levees
manmade or natural banks on the side of a river
how are natural levees formed
when a river floods its load will be deposited on the edge of its bank as water goes back into river or soil and therefore load will being to build up over time
what are estuaries
tidal part of the river (where the river meets the sea)
how does the geology of an area influence the direction of the river (use river severn as an example)
rivers will always try and find the quickest pathway to the sea, through softer tock as it is easier to erode and make a pathway through. the river severn cannot make it through the hard rock and mountains in wales and therefore travels into england where there is softer rock such as clay
how does the climate of an area influence rivers
the hotter it is the more water that will evaporate
the hotter it is the more mountain snow melts meaning there is more water in rivers causing more floods
what does the Bradshaw model show
changes in the long profile of a river from the source to the mouth
define the width and depth of a river and how these change from the source to the mouth
w - the distance from one bank to another
- gets wider as changes from source to mouth
D - the distance from the surface of the water to the river bed
- gets deeper as changes from source to mouth
define the velocity and discharge of a river and how these change from the source to the mouth
V - how fast the water is flowing
gets faster from source to mouth
D - the volume and speed at which water travels through the river channel
increases from source to mouth
define the gradient and channel roughness and how this changes from source to mouth
G - the steepness of river bed
decreases from source to mouth
CR - how rough the river beds banks are
becomes smoother from source to mouth
define sediment size and shape and how this changes from source to mouth
the material carried by the river
becomes smaller from source to mouth
what is a hydrograph and what are the two different graphs interpretated in them
a way of showing how a river responds to a rainfall event
bar graph = rainfall
line graph - river discharge
what does peak rainfall, rising limb, peak discharge and falling limb mean
peak rainfall - highest rainfall
rising limb - the rising water in river AFTER rainfall
peak discharge - most amount of water in a river
falling limb - the amount of water that decreases in a river
what does base flow and lag time mean
base flow - normal flow of river
lag time - the difference between the time of heaviest rain and the point at which the river contains the most water
what do we want the lag time to be and why
want it to be longer as it reduces floods
what factors result in a steeper hydrograph
processes that cause faster and greater surface run off such as thin soil, impermeable rocks, a lot of urban areas with concrete roads, little vegetation
what factors result in a flatter hydrograph
process that cause slower and less surface run off such thick soil with a lot of air pockets, permeable rock, woodland areas and a lot of vegetation
what does antecedent conditions mean
conditions before something such as a storm happens
give three human and three physical activities and features that may alter flood hydrographs
human - deforestation/ afforestation, urbanisation and agriculture/ irrigating crops
physical - impermeable/ permeable rocks, relief of the land, the size and height of drainage basin, seasons and weather
give a list of social, economic and environmental impacts of flooding
social
- death, injury, disease
- people without power
- loosing homes or damaged property
economic
- business lost
- tourism lost
loss of jobs
environmental
- animals killed ( biodiversity lost)
- habitats lost
give three reasons why floods are ever increasing in the uk
- increasing population, having to build on floodplains and therefore more people at risk or property flooding
- changes to land use, urban development creates more impermeable surfaces meaning there is more surface run off
- changes to weather patterns, warmer climate is causing more extreme weather
where was the flood that occurred in the uk that you have studied
the river Severn in Wales that flows into west England in July 2007. the flood mainly effected Gloucester and Tewksbury
what tributaries meet the river Severn near Tewksbury
the river Avon
why was Tewksbury at high risk during the floods
located on a floodplain and has flooded in the past, surrounded by two huge rivers therefore the confluence was in Tewksbury
what were the three causes of the flooding in the UK in 2007
high rainfall - the average rainfall was double normal amounts, 20th July 140mm fell. it was caused by a strong get stream
urban land use - a lot of towns and cities, flash floods caused overwhelmed drainage systems.
confluence of the two rivers
what were some effects of the floods in 2007 in the Uk because of the river Severn
flood water was contaminating drinking water, businesses were closed, the soil was to saturated so there was immediate run off, evacuating prisons, loosing agriculture, river was still rising after 48 hours of no rain, local farmland lost, animal habitats
what were some responses to the 2007 floods in the UK
army sent to help evacuate people, using boats and helicopters to evacuate people
how many homes were affected in the 2007 floods and how much damage cost per house
48000 houses and between £20000 and £30000
how much did the floods in 2007 cost the British economy
£3.2 billion
what is the environmental agency
they are responsible for deciding where flood defences are and what is used
what is the themes barrier
a method of hard engineering thats been operating since 1982
how does the themes barrier work
when the gates are open they are level with the river bed when closed they rise to form a metal barrier
why does the themes barrier open and close
open and close to allow river water and boats to go through
what are the four types of hard engineering and three types of soft engineering
embankments (levees), flood walls, demountable flood barriers, flood barriers
flood plane retention, river restoration, afforestation
what are embankments and positives and negatives
high banks built on river banks
- cheap, stop flooding
- can burst under pressure, water may go over top
what are floodwalls and positives and negatives
artificial barriers used to raise the height of bank
-prevent flooding in housing
- expensive, ruin view of river
what are demountable flood barriers
temporary structures that can be removed
- cheap, used where flood barrier would be ugly
- may not be installed in time
what are flood barriers and positives and negatives
built near river mouth to prevent flooding behind
- able to protect large areas
- most expensive, need regular maintenance
what are flood plane retentions and positives and negatives
strategies to maintain and restore rivers original floodplain
- cheap, allow river to slow down and recover natural settlement
- allow flooding of land may lead to change in land use
what is river restoration and positives and negatives
using a variety of stratergies to restore rivers original course
- cheap, better for wildlife
- changes land use
what is afforestation, positives and negatives
replanting trees
- cheap, environmentally friendly, absorb water
