erosion + oceans Flashcards
(32 cards)
what is hard engineering?
this involves building structures to protect the coast: they tend to be expensive
what is soft engineering?
this involves working with natural materials to protect the coast or allowing nature to take the coast
What is erosion?
the process by which the coastline gets worn away and moved elsewhere
What is hydraulic action?
The power of waves force air and water into the cracks of rocks. this pressure forces fractures in rock to split apart.
What is Abrasion?
The waves pick up rocks from the sea bed and throws them against the cliffs. This acts like sandpaper and smoothes the rocks
What is Attrition?
The sea picks up angular rocks and knocks them into each other . This chips away the corners to make them rounder
Solution
Salts or chemicals in the water act to dissolve the rocks, for example limestone is dissolved by the sea salt
What are destructive waves?
Destructive waves are waves that have high frequency, a stronger backwash than swash and cause most of the erosion on coastlines
What are constructive waves?
constructive waves are low energy waves with a stronger swash then backwash
Describe the process of longshore drift:
1) The prevailing wind pushes the wave up the beach, picking up loose material in the swash
2) The backwash drags the material back down the beach with gravity
3) the process continues to move debris down the beach
What factors are damaging our oceans?
- overfishing
- plastic pollution
- tourism
- climate change
what is a bay?
a smooth coast between two headlands
what does fetch mean?
It is the length of water a wave travels over
what is a headland?
land that juts into the sea
what is an arch?
A curved structure left standing when the sea erodes a cave away
What is a stack?
A pillar of rock left standing in the sea when the top of an arch collapses
What is a stump?
the remains of an eroded stack
What does storm surge mean?
A rise in sea levels caused by a storm
What are groynes?
barriers of wood or stone on beaches that stop sand from being washed away
How do waves form?
when wind blows over the surface of the sea, friction is created, causing a swell in the ocean
What are advantages of groynes?
- the beach is still accessible
- makes the beach wider for tourist
What is a sea wall?
Concrete walls that break up the energies of waves
What are some advantages of sea walls?
- long life span
- prevents flooding
- provides a promenade
What is an example of soft engineering?
- beach nourishment ( beaches built up with sand so the waves have to travel further before eroding cliffs )