Coastal management tries to reduce erosion or flooding. A hard mechanism is a built structure, and a soft mechanism works with natural processes. A strong answer compares them on the same criteria: cost, effect on the coast and what remains uncertain.
This lesson follows relating transport to a depositional feature and is the third step in coasts and marine processes.
What are the main methods?
| Method | Type | What it does | Main limit |
|---|---|---|---|
| Sea wall | Hard | Reflects wave energy back | High cost; can increase erosion at its base |
| Groynes | Hard | Trap drifting material to build a beach | Can starve the beach further along the coast |
| Rock armour | Hard | Absorbs wave energy | Can be unattractive |
| Beach nourishment | Soft | Adds sand or shingle | Needs repeating |
| Dune planting | Soft | Roots hold sand and absorb wind and waves | Slow; needs protection from trampling |
How do you compare two methods?
- Pick the criteria (cost, protection, effect on the coast, appearance).
- Give a fact for each method under each criterion.
- Join them with a comparing word.
- Reach a judgement and say what you would check before deciding.
Worked example
All costs are invented for practice. A town wants to protect 800 m of coast over 20 years. A sea wall costs RM 6,000 per metre to build and RM 100 per metre per year to maintain.
Beach nourishment costs RM 1,500 per metre to start, then RM 1,500 per metre again at years 5, 10 and 15.
Step 1, sea wall per metre: 6,000 + (100 × 20) = 6,000 + 2,000 = RM 8,000.
Step 2, nourishment per metre: the start plus three top-ups is 4 payments, so 4 × 1,500 = RM 6,000.
Step 3, scale to 800 m: wall 8,000 × 800 = RM 6,400,000. Nourishment 6,000 × 800 = RM 4,800,000.
Step 4, difference: 6,400,000 − 4,800,000 = RM 1,600,000 cheaper for nourishment over this period.
Step 5, judgement: “Beach nourishment costs less over 20 years, whereas the wall gives protection that lasts without topping up. The wall may also change erosion nearby, so the town would want a survey before deciding.”
The mistake to watch for
One-sided answer: “A sea wall is expensive. Beach nourishment is natural and looks nice.”
The two sentences use different criteria, so nothing is actually compared.
Correct it by using the same criterion for both: “A sea wall costs RM 8,000 per metre over 20 years, whereas nourishment costs RM 6,000 per metre.”
Another slip is to claim a method “stops” erosion. Say it reduces it in a given place and period.
Check yourself
1. Using the example, what is the cost per metre of nourishment if top-ups are only at years 7 and 14 (one start, two top-ups)?
Show answer
3 payments × 1,500 = RM 4,500 per metre.
2. Classify as hard or soft: groynes, dune planting, rock armour.
Show answer
Groynes hard, dune planting soft, rock armour hard.
3. Rewrite “The wall is strong. Nourishment is cheap.” as a comparison.
Show answer
One example: “The wall gives stronger protection per year, whereas nourishment costs less at the start but needs repeating.”
Where this leads next
Real places make comparison harder, because the facts need dates and sources. Go on to using a sourced case with its date and limits. The Geography evidence and case-study ledger can hold the facts you collect.
If your answers keep sounding like two lists, our teachers in online one-to-one Geography tuition can practise comparison paragraphs with you.