Coasts - Geography Flashcards
Geography
What is the coastline?
The area where land meets the sea
4 Types of coastal erosion
Hydraulic action
Abrasion
Attrition
Solution
What are the two main types of coastal processes?
Erosion and deposition.
How does a Waterfall form?
Layers of Rock – Waterfalls have layers of hard rock (resistant rock) on top of soft rock (less resistant rock).
Erosion – river erodes softer rock quicker through hydraulic action (water forcing into cracks) and abrasion (rocks scraping against the bed).
Undercutting – When soft rock erodes, overhang of hard rock forms.
Collapse – Eventually, overhang becomes too heavy and collapses
Plunge Pool – The fallen rocks help deepen the base, forming a plunge pool due vertical erosion
Retreat – process repeats over time, causing waterfall to move upstream and create a gorge behind it.
What is the primary cause of wave formation?
Wind blowing across the surface of the water.
What is longshore drift?
The movement of sand along the beach caused by waves hitting at an angle.
Hard Management ways at stopping the sea eroding the sea
Construction of sea walls
Formation of a spit?
Longshore Drift – Waves approach coast atangle due to prevailing wind, carrying sediment along the shore in zigzag pattern.
Deposition – coastline suddenly changes direction, sediment is deposited
Spit Growth – Over time, deposited material builds up forming a long, narrow strip of land
Curved End – end of spit may curve due to changes in wind or wave direction, forming hooked shape.
Salt Marsh Formation – The sheltered area behind the spit becomes a mudflat or salt marsh, due to its low energy
Soft engineering ways of reducing erosion at the coast
Beach replenishment
Sand dune regeneration
What is a discordant coastline
Alternating layers of hard and sock rock
Characteristics of Destructive waves?
Tall
Close together
Plunging
Strong backwash
Weak swash
Loss beach sediment
Characteristics of Constructive waves?
Shallow
Far apart
Spilling
Strong Swash
Weak backwash
Gain beach sediment
What is the difference between constructive and destructive waves?
Constructive waves build up beaches, while destructive waves erode them.
How does a Cave, Arch, Stack, Stump form?
- Faults form in rock. Abrasion, Hydraulic action
- Fault widens to form cave
- Cave eroded through, arch forms
- Arch falls due to gravity/weathering/erosion leaving stack
- Stack eroded leaving stump
How do sand dunes form?
Sand - grow when dry sand blown off beach
Wind - Blown off in shoreward direction
Obstacle - Sand moves until its meets a slight obstruction
Plant - e.g grass which causes sand grains to drop
Small mound created
Plants colonise
Mound grows in size
Wind moves sand up so keeps growing
Conditions needed for coral to survive?
Common temperature of 23 - 29 degrees
Clear water which allows sunlight through
Prefers saltier water
Plentiful amount of plankton and oxygen
Calm waters
Shallow waters, less than 60m deep
Conditions needed for mangroves to form?
Water above 25 degrees in summer months
At least 1250mm rainfall per year
Sheltered, calm waters
Shallow, salty waters
Nutrient rich sediment
What factors influence coastal erosion?
Wave energy, rock type, and human activities.
Happisburgh case study opportunities?
Tourism provides 10% of jobs
Popular tourist destination - connected to London by bus
Beauty, relaxing lifestyle
Some historic sites - e.g wooly mammoth
Fishing for herring
Great Barrier reef case study
Main threat is climate change
Sea becomes acidic - damaging coral health
35.9% of energy came from renewables in 2022, 3.4% increase from year before
25% of world’s fish depend on reef for survival/reproduction
Damaging fishing practices
Great Barrier Reef Park Authority has zoned 33% of reef off bounds to fishing
Coral cannot have sediment
Convention to stop oil spills/dumping
2015, QW gov committed $1 billion to clean up the reef
Mangroves should be planted
What are the different types of reef
Fringing - Grow out to sea but attached to mainland
Barrier - form offshore barriers against coastlines
Atoll - grow in circle around island
What role do coral reefs play in coastal protection?
They act as natural barriers against wave energy.
Hazards of living by the coast?
Cliff collapse
Big storms
Tsunamis
Flooding
Contaminate freshwater supplies
Sea level rise
Why are Mangroves and Coral good for the ecosystems?
Coastal protection
Breeding ground for many fish
Can be used for farming prawns/oysters
Mangroves absorb lots of CO2
Symbiotic relationship
Dead coral provides sand
