Coasts - Lesson 4 Flashcards
What is a cross-section of a beach called?
A beach profile.
What is longshore drift?
It is a zig-zaggy motion by which beach material is transported along the coastline in the direction of the wind.
What are beaches made up of?
Eroded material that has been transported from elsewhere and deposited by the sea.
How are spits formed?
At river estuaries LSD carries materials out into the rivers mouth, forming a sandbank called a ‘spit’.
What cannot spits do and why?
The are unable to stretch across the entire estuary as the river will continue to erode a path.
What causes new land to form at a spit?
In sheltered waters behind the spit ‘alluvium’ will build up, forming salt marshes -> land.
How are most spits curved?
Most are curved by periodic changes in wind direction which forms waves in a different direction, resulting in the spit being pushed upriver.
What are constructive waves?
Waves that help make a beach higher, longer and wider.
Name at least four types of hard engineering.
Sea wall
Groynes
Boulders
Rock armour
What is swash?
When waves break and water carrying beach material is pushed up at an angle onto the beach due to the wind energy they have.
What is backwash?
When waves lose wind energy when breaking and the beach material on the shore is carried down the beach perpendicularly due to gravity.
What is hard engineering?
An expensive, short-term and unsustainable way to deal with coastal problems.
