中文（繁體）
中文（简体）
English
S5 Geography | Coastal Landforms and Sea-Level Rise Paper 3 (Challenge)
S5 Geography | Coastal Landforms and Sea-Level Rise Paper 3 (Challenge)
Paper 3 handles trade-offs and compounding effects: long-run costs of hard and soft engineering, cliff volume loss, surge riding on higher seas, marsh drowning, sediment budgets and material costs.
Compare over the same timescale Allow about thirty-five minutes; for cost items bring both options onto the same period before comparing cumulative spending.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 items |
| Suggested time | About 35 minutes |
| Difficulty mix | Foundation 4 · Intermediate 2 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S5 Geography | Coastal Landforms and Sea-Level Rise |
| Level | S5 (Secondary 5) Geography |
02 Questions (10 items)
- FoundationA sea wall costs $12,600,000 and lasts 30 years, while nourishment costs $11,400,000 every 5 years. How do the 30-year totals differ?
- FoundationWave height rises from 1.2 m to 3.6 m with period unchanged. By what factor does energy rise?
- FoundationOver 60 years sea level rises 4.5 mm a year on average and the beach slope is 1/80. What are the total rise and the shoreline retreat?
- FoundationA beach gains 45,000 m³ of sand a year but loses 62,000 m³, with 170,000 m³ in store. What is the net change and how long until it is exhausted?
- IntermediateA salt marsh gains 1.8 mm a year from organic matter and 2.9 mm from mineral sediment while sea level rises 6.0 mm a year. How much relative drowning in 40 years?
- IntermediateA 1-in-50-year storm surge peaks at 3.2 m today, sea level rises another 0.45 m and the existing sea wall is 3.5 m high. Is it adequate?
- ChallengeWave A is 2.0 m high with a 9 s period, wave B is 3.0 m high with a 7 s period. How many times more energy does B carry?
- ChallengeA 25 m high cliff retreats 0.2 m a year. How much rock is lost per metre of coast each year, and over 1 km in 50 years?
- ChallengeImported sand costs $95 per m³, while local sand costs $58 plus $34 delivery. What percentage is saved per m³?
- Error redoError retry: with 0.45 m of sea-level rise a student answers that the shoreline retreats 0.45 m. What is correct for a beach slope of 1/80?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | Six nourishments cost $68,400,000, which is $55,800,000 more than the wall. | Hard engineering is a single outlay while soft engineering recurs, so alternatives must be compared over the same period. |
| 2 | 9 times. | Tripling the height multiplies energy by nine, so a modest change in height has a large effect on the square. |
| 3 | A total rise of 0.27 m (270 mm) and a retreat of 21.6 m. | Convert the 60-year total to metres first, then divide by the 0.0125 slope; skipping either step spoils the answer. |
| 4 | A net loss of 17,000 m³ a year, exhausted in 10 years. | Take the net of the sediment budget first, then divide the store by that net loss for the sustainable lifespan. |
| 5 | Together 4.7 mm a year, a shortfall of 1.3 mm a year, so 52 mm in 40 years. | The two sources add to total accretion, and whatever falls short of sea-level rise becomes relative drowning. |
| 6 | The surge reaches 3.65 m, which overtops the wall by 0.15 m, so it is not adequate. | Design standards compare the new surge level with wall crest height; using the old level alone understates the risk. |
| 7 | About 1.75 times (63 / 36). | Height squared times period measures energy, so B is taller but shorter and the factor stays below 2.25. |
| 8 | 5 m³ per metre each year, and 250,000 m³ over 1 km in 50 years. | Cliff height times annual retreat gives loss per metre, and multiplying by coast length and years gives the total. |
| 9 | Local sand costs $92, saving about 3.2%. | Add the two local cost items first, then compare with the imported price, using that price as the denominator. |
| 10 | The correct retreat is 36 m. | Rise is not retreat: retreat divides the rise by the slope, so flatter beaches lose far more ground. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Need a tutor for this chapter? Register hereTutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.