Physical Flashcards
Igneous formation and an example
Formed from magma, Granite
Sedimentary formation and an examples
Formed from compressed sediment: chalk, clay, limestone
Metamorphic formation and examples
Igneous or sedimentary changes under high heat and pressure: Slate, schists
Chalk properties, where is it found?
Strong, permeable,
Found in lowland Britain
Clay properties and where is it found?
Weak and impermeable
Found throughout Britain
What geology is found in Highland Britain
Igneous and Metamorphic
What geology is found in lowland Britain
Sedimentary
What divides lowland Britain from highland Britain
Tees-exe Line
Granite Properties
Hard, resistant to erosion, impermeable, susceptible to chemical weathering,
Metamorphic properties.
Very strong and very resistant erosion and weathering
Granite landscapes are?
Poorly drained and boggy
Clay landscapes are?
Flat plains with lots of lakes and rivers
How can Agriculture affect UK landscapes?
Trees removed, drainage ditches
How can Forestry affect the UK landscape?
Trees planted in straight rows for management,
How have settlements affected the UK landscape?
Settlements build at meander loops, natural harbours, shallow points in rivers and by springs
Characteristics of a soft rock (eg.Clay)
Easily eroded by the sea, cliffs are less rugged and less steep, forms bays.
Characteristics of hard rocks (eg. Granite)
Resistant to erosion, steep cliffs, wave cut platforms, caves and arches and stacks are formed.
Concordant coasts
Same rock types are parallel to the sea,
Discordant coasts, and what they form
Discordant coastlines are perpendicular to the sea.
Headlands and bays are formed
What can make a rock more susceptible to erosion?
Joints and faults.
How are arches formed?
2 caves eroded either side of the headland meet.
How are caves formed?
Weaknesses such as joints and faults are eroded
How are stacks formed?
When an arch collapses
How are stumps formed
When a stack is eroded.
Hydraulic action
Force of the water hitting the coast, compresses air in faults and joints forcing them apart weakening the rock
Abrasion
Waves throw pebbles at coast during a storm.
Attrition
Pebbles and rocks rub against each other and become smaller and rounder
Solution
Chemical action by seawater on some rocks.
Freeze-thaw weathering in winter
Water expands in faults and joints forcing the rock apart.
Destructive wave
Swash (towards) is weak but the backwash (away) is strong. This drags material into the sea.
Prevailing wind
South westerly,
brings warms and moist air from the Atlantic and frequent rainfall.
Storm frequency and coastal erosion
Makes coasts subject to strong winds and heavy rainfall, encouraging mass movements
Mechanical weathering
Freeze-thaw
Biological weathering
Plants and animals encourage mechanical and chemical weathering, eg. Tree roots widen gaps in rocks.
Chemical weathering
Limestone is dissolved by carbonation. Carbon Dioxide in atmosphere combines with rainwater creating Carbonic Acid.
Mass movement
Downhill movement of material under the influence of gravity. Eg. slumps
What does coastal erosion result in
Coastal retreat.
Longshore drift
Waves approach at an angle. Swash (Towards) pushes sand and gravel up the beach. Backwash brings it back down perpendicular to the sea. It moves down the beach in a zig-zag fashion.
Types of transportation
Traction, saltation, suspension, solution.
Traction
Large boulders are rolled along bed by waves
Saltation
Smaller stones are bounced along bed
Suspension
Sand and small particles are along in the flow.
Solution.
Minerals dissolved in seawater and carried along in flow.
Constructive wave
Strong swash (towards) weak backwash (away). Load is deposited. (Deposition). Caused by sheltered spots (bays), calm conditions, friction by gentle gradient.
Spits
When longshore drift pushes into bay or an estuary when the coast changes direction
Bars
Bars caused by longshore drift, grow across a bay cutting off water to form a lagoon.
Development impact on coasts
Positive ✅ -Raises interest in protecting coastal landscapes
Negative ❌ -Weight of buildings increase cliff vulnerability
❌ -Changes in drainage increase saturation
Industry impact on coasts
Positive ✅ -Brings wealth and jobs to the area
Negative ❌ -Causes air, soil, water and noise pollution to increase
❌ -Destroy natural habitats for birds, animals and sea life.
Agriculture impact on coasts
Positive ✅ - Wildlife habitats may be created and preserved.
Negative ❌ - Increased soil erosion
❌ - Increased sedimentation
Coastal management impacts on coasts
Positive ✅ -Helps reduce risk of coastal flooding
✅ -Salt marshes, sand dunes, sand bars, spits are preserved
Negative ❌ -Can increase erosion further along the coastline
Tourism
Positive
✅ -Increased revenue benefits people living there
✅ -Increased desire to protect landscape in order to maintain tourism
Negative ❌ - Increased pollution (litter, noise, traffic fumes)
❌ - Increased development (see development impacts card)
Climate change impact on coastal flooding
⬆️ Increased storm frequency which increases height and power of waves, Heavy rainfall
⬆️Increased global temperature causes water to expand, and it melts ice: increasing the volume of the water
Impact of Climate change on coastal environment:
Erosion may increase, beaches disappear
Depositional features (spits and bars) may be submerged or destroyed.
Natural eco-systems (Essex marshes) and habitats may be destroyed.
Increased coastal retreat and risk of cliff collapse.
How are wave-cut platforms formed?
The water erodes the base of a cliff, the cliff becomes undercut and collapses.
How are sandy beaches formed
Gentle sloping profiles
How are shingle beaches formed
Steeper gradient
Where is smaller sediment deposited on the beach
By the water
Where is larger sediment deposited
Far from water
What is a tombolo
Where LSD connects land and an island
Dry valley and how they form
Permeable rocks drain away water, leaves a dry valley
What area of the UK is most exposed to destructive waves.
The South-West coast, because prevailing wind from the Atlantic Ocean
How are storm surges formed
Low pressure causes water to bulge, wind pushes it towards coast.
Which places in the UK are most vulnerable to sea level rise and
storm surges.
East coast funnels storm surges.
How does isostatic change (post-glacial rebound) contribute to flooding.
The south is descending due to the north losing the weight.
Hard engineering
Expensive, short-term options, large impact on environment, un-sustainable
Soft engineering
less expensive, long-term and sustainable, less impact on the environment.
3 options to shoreline management
Do nothing, Hold the line, strategic re-alignmrnt
Strategic re-alignment
Allow the shoreline to retreat. Until a point where you hold a new line.
Why are there conflicting views about management of coastlines.
Property may be lost if nothing is done, Holding the line is expensive, strategic re-alignment may be unpopular
What is CBA, how is it calculated
Cost-benefit-analysis,
Value of land protected /Cost of defence over x years
How are floodplains formed.
Lower course meanders widening the valley making it flatter. Deposition of sediment every flood .
Source
The origin of a river
Mouth
Where the river meets the sea
Tributary
River or stream flowing into a larger river
Watershed
The boundary of the drainage basin
Drainage basin
The area of land where water is drained into a river
Confluence
The point where 2 rivers join
Upper course:
Gradient, discharge, depth, Chanel shape, velocity, valley shape, features.
Steep, small, shallow, narrow, quite fast, steep sides, waterfalls, interlocking Spurs
Middle course:
Gradient, discharge, depth, Chanel shape, velocity, valley shape, features.
Less steep, large, deeper, flat, fast, steep sides, meanders, floodplain
Lower course:
Gradient, discharge, depth, Chanel shape, velocity, valley shape, features.
Shallow gradient, very large, deep, flat floor, very fast, gently sloping sides, meanders, ox-bow lakes.
Interlocking Spurs
Upper course, flows naturally side to side due to limited energy
Levées
When a river floods sediment is deposited by the side of the river. This forms steep levées
Deltas
River velocity rapidly decreases as it approaches the sea, depositing its sediment, creating new area of land, it divides the river into many streams.
How is erosion rate changed
Increased discharge and velocity,
How is transportation rate affected
Increased energy of water
How is weathering affected
Temperature can cause free-thaw weathering
How is discharge affected
Climate, Wet climates = greater
What is discharge measured in
M^3/s
What 2 things do storm hydrographs present?
Discharge, rainfall
How do you calculate lag time
Time difference between peak rain and discharge
What is rainfall measured in
Millimetres (mm)
How does lag time affect risk of flooding
The less the lag time the more likely floods
What factors affect lag time
Geology, soil type, vegetation, slope, drainage basin shape, antecedent conditions(saturated ground)
Human activities contributing to flooding
Urbanisation, land-use change, deforestation, building on floodplains
Climate change and flood risk
Increased storm frequency- increased rainfall
Increased hot and dry periods-baked soil causes surface run off
Increased frozen period- frozen soil causes surface run off.
Threats of flooding to people and environment
Damage to property, death/injury to people/animals, farmland damaged causing crops to fail causing food supply issues, affects sanitation spreading diseases suck as collera
Hard engineering fo flood risk
Levées, flood walls, dams/reservoirs, flood barriers
Soft engineering for flood risk
River restoration, washlands, floodplain retention, planting trees
