Coasts Flashcards
What is geology?
The type of bedrock in an area
How can geology impact erosion?
Different rock types have different resistances to erosion
What are the 4 sections of the littoral zone
Backshore
Foreshore
Nearshore
Offshore
What is Coastal morphology?
The shape and physical characteristics of a coastline
What is Lithology?
The physical characteristics of a type of rock
e.g , Strata, joints, folds, faults, dip, permeability
What are the 5 main cliff profiles?
Horizontal dip (steep cliff)
low-angle Seaward dip (overhang cliff)
high-angle seaward dip (slabs slide down cliff face)
Low-angle landward dip (very stable cliff)
high-angle landward dip (same shape as high-angle seaward dip)
How does a concordant coat form?
Rock strata run parallel to the coast
More resistant rock gets a weakness exploited creating a hole to less resistant rock behind
Less resistant rock is eroded quicker forming a cove
How does a discordant coast form?
Rock strata run perpendicular to coast
Less resistant rock erode quicker than more resistant rock
Forms headlands and bays
Which rock type is most and least resistant to erosion?
Igneous (most)
Sedimentary (least)
Metamorphic (middle)
What allows beaches to form in bays?
Waves hit the headland first (more resistant)
Causes wave refraction where the energy is decreased
Not enough energy remains to erode sediment allowing it to build up
What effects wave energy at a coast?
Strength of prevailing winds
Fetch
Compare the features of Constructive and Destructive waves
Constructive has strong swash and weak backwash, found at low energy coasts
Destructive has weak swash and a strong backwash, found at high energy coasts
How do summer and winter beach profiles vary?
Steeper in the summer, swash of low energy waves builds a berm
In winter the berm is eroded by destructive waves and strong backwash forms offshore bars
What are the 4 types of erosion?
Abrasion
Attrition
Hydraulic Action
Solution
What are the main erosional landforms?
Wave cut platforms/ notches
Cliffs
Caves, Arches, Stacks and Stumps
Describe the process of longshore drift?
Waves approach at an angle due to prevailing winds
Swash deposits sediment on an angle
Backwash removes sediment straight out to sea
Cycle continues moving sediment along the shoreline
What are the 4 types of marine transport?
Traction
Saltation
Suspension
Solution
What impact can tides have on longshore drift?
The relative difference between high and low tides is called tidal range
A high tidal range produces strong tidal currents which transport more sediment
How does a spit form?
Longshore drift transports sediment along the coast
The direction of the coast changes suddenly (e.g river estuary)
Longshore drift caries on depositing sediment forming a protrusion called a spit
What is a barrier bar?
A spit that joins at both sides forming a lagoon behind it
What is a tombolo?
A narrow beach that forms between a small island and the coast
What are cuspate forelands?
Triangular headland formed by longshore drift in opposite directions
vegetation stabilises the sediment making it more resistant to erosion
Give examples of coastal vegetation
Dunes
Marshes
Mangroves
What is the name given to a plant that is resistant to salt?
Halophytes
What is the name given to a plant that is resistant to arid conditions?
Xerophytes
What are sediment cells?
Sections of the coast where sediment is transported between
Act as systems with sources, flows and sinks that act in a dynamic equilibrium
What are the two types of Sub-aerial processes?
Mass Movement
weathering
What are the 3 types of weathering?
Mechanical (Freeze-thaw, Salt weathering, Wetting-Drying)
Biological (Plant roots, Acidic Water from decaying matter, Burrowing Animals)
Chemical (Acid rain)
Give example of mass movement flows?
Soil Creep
Solifluction
Mudflows
Give example of mass movement slides?
Rock falls
Rock slides
Slumps
What are the two main causes of contemporary sea level rise?
Thermal Expansion
Polar Ice sheet melting
What are the two types of long-term sea level change?
Eustatic Change
Isostatic change
What are the two main emergent landforms?
Raised Beaches, have a terraced like structure due to uplift of land
Relic Cliffs, remains of where cliffs, caves, arches etc are raised above the sea level
What are the three main submergent landforms?
Rias, valleys become flooded due to sea level rise, common in south east England
Fjords, glacial valleys become flooded due to sea level rise, common in Iceland
Dalmatian Coast, River valleys flow parallel to coast and then become flooded forming long narrow islands. Common in Croatia
What is the geology of the Holderness?
Boulder Clay
Describe the fetch at the Holderness?
Not that big (500-800 km)
Currents circulate round the north of Scotland and combine near the Holderness adding energy to waves
Lots of low-pressure systems pass the area
Deep sea floor means little friction for waves so they maintain their energy
Who are the main stakeholders in the Holderness?
Central and Local government - responsible for management of the area
Stakeholders in local economy - Tourism industry and farmers
Environmental stakeholders - RSPB want to protect spurns head as the marshes are home to rare birds
What is terminal groyne syndrome?
Groynes trap sediment at one part of the coast, this starves areas further down of sediment
Name a place where terminal groyne syndrome has occured
Sea wall, rip rap and groynes were build at Hornsea to protect beach
This starved Mappleton beach of sediment increasing erosion in the area
Why is Bangladesh at risk of flooding?
Worlds most densely populated country
Very low relief, 46% of population live <10m above sea level
Has lots of large rivers that lead all the way up into the country and near to the capital
Why is flood risk increasing in Bangladesh?
Clearing land for cultivation is causing soil erosion and subsidence which is making rivers larger and islands are shrinking
70% of Mangroves have been removed, they act as a natural barrier by refracting wave energy and storm surges
What year did the UK experience extreme storms and storm surges?
2013
What caused the 2013 storm surge in the UK?
Intense low pressure
Sea shape and coast - sea funnels in towards the south which squeezed the surge making it bigger
Sea Depth - sea gets shallower towards the south increasing wave shoaling
High seasonal tides
What were the impacts of the 2013 storm and storm surge in UK?
Gusts of over 200 km/hr in Scotland
Thames Barrier closed
In Norfolk properties fell into the sea
1400 homes flooded
Rail services in the east and south were disrupted
Evacuation occurred across the east coast and in Wales
How will climate change affect the frequency and range of Hurricanes?
Warmer ocean temperatures for longer periods of time will make hurricanes more frequent
Areas further north and south of the equator will have temperatures high enough to form hurricanes, meaning they will occur at a wider range of latitudes
Give examples of hard engineering
Groynes Sea Walls Rip Rap Revetments Offshore Breakwaters
Give examples of soft engineering
Beach Nourishment
Cliff re-grading
Dune stabilisation
Marsh creation
Give examples of hard engineering at the Holderness
Hornsea - Sea wall, groynes, rip rap
Mappleton - Rock groynes, rip rap
Withernsea - Curved sea wall
What is a CBA?
Cost benefit analysis, used to decide if an area is in need of defences by weighing up the potential costs with the expected benefits
What are the two types of costs and benefits in a CBA?
Tangible - costs and benefits are known and gan be given as a value e.g monetary costs
Intangible - Costs and benefits are harder to assess but are still important e.g aesthetic value
What is ICZM?
Integrated Coastal Zone Management - a strategy that involves managing the coast as a whole, this is because actions on one area of the coast can have huge impacts on other areas
What is Odisha, India under stress from?
Rapid industrialisation Fishing and Aquaculture Tourism Mining and Oil and Gas production Erosion, rising sea levels and increase in Cyclones
What are the aims of ICZM in Odisha?
Control coastal erosion
Developing Eco-tourism
Replanting Mangroves
What is the SMP and which section affects the Holderness?
The Shoreline Management Plan is a type of ICZM in the UK, aiming to reduce and manage erosion for the next 100 years
It is split into cells and the one affecting the Holderness is the Flamborough Head to Gibraltar Point
What are the 4 options for the SMP?
Hold the Line
Advance the Line
Managed Realignment
Do Nothing
What is an EIA?
Environmental impact assessment, decides whether the environmental quality will improve, worsen or stay the same as a result of action
What does the SMP look like for the Holderness?
Mostly do nothing at low value coastal areas
Hold the line at areas with a high value asset e.g towns like Hornsea, Mappleton, Withernsea and Easington (especially due to gas terminals)
Managed realignment at Spurns Head
