Physical Landscape Flashcards
What are waves formed by
A wave is formed by the transfer of energy. The friction of the prevailing wind on the water causes waves
Why do waves slow down at the beach
Due to friction of the water on the sand
What are the two types of waves
Constructive and destructive
What are the characteristics of constructive waves
A strong swash and weak backwash, often found at sheltered bays, and a flat beach
What are the characteristics of destructive waves
A steep beach
a strong backwash and a weak swash, often found at headlands
What are different attributes of waves
Crest, trough, wave height, wave length, wave frequency
What is weathering
The breaking down of rock
What are the different types of chemical weathering
Carbonation- carbonic acid in rainwater reacts with calcium carbonate to form calcium bicarbonate
Hydrolysis - acidic water breaks down rock
Oxidation - rocks are broken down by oxygen, such as rusting
What are different types of mechanical weathering
Freeze thaw weathering - water enters crack and when the temperature is below zero, the water freezes and expands by around 9 %, increasing the crack over time.
Salt weathering - salt builds up in cracks and crystallises, putting pressure on the crack
What is mass movement
The downslope movement of rock, soil or mud under the influence of gravity
What are different types of mass movement
Sliding - e.g. landslide - downhill movement of a large amount of rock, soil or mud
Rock fall - rock fall from a cliff face as scree
Slumping - material rotates as it falls down a concave slip plane
What are the different types of erosion
Attrition, abrasion, hydraulic power, solution
What is attrition
The grinding of load particles - rocks hitting each other wear them out to make smoother pebbles
What is hydraulic action
Force of destructive waves on rock
What is abrasion
The sand paper effect of sand and shingle on rock
what is the name given to the process that transports sediment across a shoreline
Longshore drift
What causes sediment to be dropped
A spit, where the shore ends
A loss of energy, in sheltered bays where constructive waves don’t have a lot of energy
large expanses of flat beach, where the swash spreads over a large area
What is the name given to erosion which occurs at different rates on a coastline
Differential erosion
What is a coastline called where there are alternating bands of rock
Discordant coastline
Are headlands usually made of hard or soft rock
Hard rock as they have not eroded
Give some characteristics of a wave cut platform
Covered at high tide and exposed at low tide
Slopes gently down to the sea
Give four coastal landforms
Cave
Arch
Stack
Stump
What are the different dunes in the dune progression (starting nearest to the water)
Embryo dunes
Grey dune
Yellow dune
Wasting dunes
How is a dune formed
Sand is carried by wind and transported by saltation, hits an obstacle and is deposited
Where are spits formed
At a bend in the coastline or at an estuary
What causes deposition of sediment
Loss of energy
What is longshore drift
The movement of sediment along a coastline due to a prevailing wind
Name four methods of hard engineering used in coastal management
Sea walls
Gabions
Groynes
Rock armour
What is the downside of groynes
Can cause erosion further down a coast
Known as terminal groyne syndrome
What are three methods of soft engineering
Beach nourishment
Dune regeneration
Beach reprofiling
What is managed retreat
Allowing the natural erosion to occur in a controlled manner
What are four types of sediment transportation
Solution
Saltation
Traction
Suspension
Why is sediment deposited in rivers
The velocity falls
What is the long profile of a river
The gradient of the river as it journeys from source to mouth
What is the load like in the upper course
Large, jagged as they have not been eroded
In which course is the velocity of a river the highest
Lower course
In which courses are vertical erosion and lateral erosion more prevalent
Upper - mostly vertical
Middle - less vertical, more lateral
Lower - very little vertical, mostly lateral
What is the cross profile like in the upper course of a river
V-shaped valley, interlocking spurs
What is the cross profile like in the lower course
Wider with flood plains on either side
Name two landforms found in the upper course of a river
Interlocking spurs
Waterfall
Gorge
Rapids
What must the type of rock be like for a waterfall to form
A junction between hard rock and soft rock so differential erosion occurs
Name the key terms involved in the formation of a waterfall
Hard / Soft rock
Differential erosion
Cap rock
Plunge pool
Splashback
hydraulic action
Name two landforms found in the middle course
Meanders
Oxbow lake
Floodplain
Name two landforms found in the lower course
Levees
Floodplains
Estuary
What are the characteristics of the inside bend of a meander
Slip off slope
Gentle gradient
Sediment deposited due to lower energy
Slow flowing water
What are the characteristics of the outside bend of a meander
Fast flowing water
River cliff due to erosion
State the key terms in the formation of a meander
Riffles - shallow areas
Pools - deep areas
Corkscrew motion
Helicoidal flow
How is an ox-bow lake formed
Two necks of a meander are connected as the river floods and takes the straightest path possible
What are levees
Naturally raised river banks
How is a levee formed
A river bursts its banks and floods
Sediment is deposited due to friction and loss of energy
Heavier sediment dropped closest to river
Finer sediment, such as silt and alluvium, dropped further from river
Why do levees not necessarily decrease flooding
The bed of the river also raises due to deposited sediment
What are some characteristics of an estuary
May be very wide and has a large body of water
High tidal range
Mudflats
Salt marshes
What is interception
The rainfall is prevented from reaching the ground as it is intercepted by trees and other obstacles
What is infiltration
Water sinks into rock or soil
What is surface runoff
Water flowing on top of the ground
How can geology increase flood risk
Hard rocks, such as in mountains, can be impermeable and therefore reduce infiltration and increase surface runoff
How can relief increase flood risk
Steep slopes mean that the surface runoff is greater than the infiltration
How can urban land use increase flood risk
Increased building on greenfield sites reduces infiltration due to tarmac and concrete surfaces
Disappearing gardens - many people are converting gardens into paved areas, for parking or other reasons
How is rural land use increasing flood risk
Felling trees reduces interception and absorption of water from roots, increase surface runoff
Farming - furrows can increase surface runoff
Disappearing fields - they can be sold to developers
What does the rising limb show on a hydrograph
How quickly the discharge of a river is increasing
What is the lag time
The time between peak rainfall and peak discharge
What does base flow show
The normal discharge - can be used to compare against the discharge measured during rainfall
What are four hard engineering strategies which reduce flood risk
Dams and reservoirs
Channel straightening
Embankments
Flood relief channels
What are four soft engineering strategies which reduce flood risk
Flood plain zoning
Planting trees
River restoration
Flood warnings and preparation
What is an example of a relief channel in the UK
Jubilee River - located near Windsor, Eton and Old Windsor
How much did the Jubilee river cost
£110 million
How many weirs does the Jubilee River have
5
What are some social issues that arose from the Jubilee River
Affluent areas such as Windsor and Eton were protected from flooding, whereas the less wealthy areas of Wraysbury and Old Windsor are prone to higher risk of flooding due to higher discharge
Some weirs are not navigable by paddle boaters
What are some environmental issues that arose from the Jubilee river
Extensive flooding downstream where the flood relief channel re-joined the Thames
Algae build up behind the weirs, disrupting ecosystems
What are some economic issues that arose from the Jubilee river
Huge maintenance costs - the initial repair bill for Slough weir after flooding was £680,000
EA ran short of money as there was a projected cost of £330 million for four relief channels
