Coastal Systems and Landscapes
THE BIG IDEA
“This topic is about how the sea and the land interact. Think of the coast as a big machine where waves and wind (energy) move sand and rocks (sediment) around to build things like beaches or tear down things like cliffs. We study how these shapes are made, how sea levels change, and how humans try to protect the coastline from being washed away.“
CRUCIAL KEYWORDS
Longshore Drift
The way waves move sand and pebbles along the beach in a zig-zag pattern.
Eustatic Change
When the total amount of water in the ocean changes, like a bathtub filling up or draining.
Isostatic Change
When the land itself sinks or rises, like a person sitting on or getting off a foam mattress.
Submergent Landforms
A closed section of the coast where sand stays inside and doesn’t really leak out to other areas.
Infiltration
Land shapes that are now mostly underwater because the sea level rose.
How It Works
1) Sediment Budgets
Think of it like a bank account. If you put more sand in (income) than the waves take out (spending), your beach gets bigger.
2) Negative Feedback Loops
It is like a self-correcting system; if a big storm moves too much sand, the new shape of the beach helps slow down future waves to fix the damage.
3) Constructive vs Destructive Waves
Constructive waves are ‘builders’ that push sand up the beach. Destructive waves are ‘thieves’ that pull sand away into the sea.
CASE STUDY EVIDENCE
- The Holderness Coast is disappearing quickly because its cliffs are made of soft clay that melts away easily when hit by the sea.
- In Odisha, they are planting trees like mangroves to act as a natural shield against huge storms and waves.
- A massive flood in 1953 was so scary that it forced the UK to build the huge Thames Barrier to keep London safe.
EXAM ESSENTIALS
- When writing long answers, make sure to talk about both nature’s power and what people are doing.
- Remember that the coast is always trying to balance itself out, even when things are changing.
- Don’t just talk about waves; remember that wind and rivers also bring sand to the beach.