Changing coastal environments
Explain wave and sediment processes, coastal landforms, tropical-storm risk and management of coasts, reefs and mangroves.
Exam scope and assessment notes
Cambridge IGCSE (9–1) Geography 0976, 2027–2029 syllabus, Topic 2. The syllabus does not prescribe one universal set of named detailed specific examples: centres select places suited to their learners. Sixteen optional StudyForA evidence packs now cover all sixteen example objectives, but the centre's choices are unconfirmed. Match each pack to your centre's chosen place and replace any mismatch before treating the course as complete. Original StudyForA explanations and self-check practice are not Cambridge papers, official grades or teacher-marked coursework. Map, graph and written answers are not automatically assessed. Paper 4 practice uses supplied or invented data and cannot certify safe fieldwork, equipment use or real data collection. Centre-set coursework and specialist teacher review remain pending. This is the separate 9–1 qualification. Cambridge limits this 9–1 syllabus to certain zones: in June it is available in Administrative Zone 3 and for centres in Oman and the UAE; in November it is available in Zone 3 only. Confirm the exam series and entry with your centre. Cambridge also says an entry cannot be switched from 9–1 to A*–G after the entries deadline.
Before you begin
- No previous Geography course is assumed. Use the supplied map, data or scenario; distinguish observation from explanation and support conclusions with evidence.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which usually has stronger swash: a constructive or destructive wave?
What you will learn
- Explain erosion, transport, deposition, wave types and refraction
- Describe coastal landforms and concordant/discordant coastlines
- Assess coastal opportunities and hazards
- Evaluate erosion, storm, reef and mangrove management using detailed examples
Waves move and sort coastal material
Hydraulic action, corrasion, corrosion and attrition erode coasts. Longshore drift moves sediment when waves approach at an angle and backwash returns downslope. Constructive waves have stronger swash and weaker backwash, often building beaches; destructive waves have stronger backwash and often remove material. Wave refraction concentrates energy on headlands and disperses it in bays.
Concordant coastlines have bands of rock parallel to the coast; discordant coastlines have bands meeting the coast at an angle. Differential erosion can expose headlands and bays where rock resistance varies.
Landforms preserve process evidence
Cracks may widen into caves, arches, stacks and stumps as wave erosion and gravity act on a headland. Wave-cut notches and platforms form as cliffs retreat. Deposited material can form beaches, spits and bars; wind can move dry beach sand into dunes. Link the landform to the process and the direction of sediment movement.
Coasts are valuable and exposed
Coastal locations can support ports, tourism, fishing, trade and settlements, while erosion, flooding and tropical storms threaten lives and assets. Storm impacts vary with wind speed, rainfall, surge, slope, settlement density, building quality, warning and preparedness.
Hard engineering (sea walls, groynes, rock armour) may protect selected places but can be expensive or shift erosion. Soft strategies (beach nourishment, managed retreat, zoning, mangrove restoration) work with coastal processes but need space, time and community support. Coral reefs and mangroves support biodiversity, fisheries and coastal protection, but face pressures such as warming, pollution and construction. Evaluate effectiveness, who benefits and the effects beyond the defended site.
Pause and explain
What makes managed retreat different from a sea wall?
Worked example
Waves approach a straight beach at 30° to the shore. Explain how longshore drift moves sediment along the coast.
Show the worked solution
- Swash carries sediment up the beach at the approach angle.
- Backwash travels downslope close to perpendicular under gravity.
- Repeated angled swash and downslope backwash create a net zigzag movement alongshore.
Answer Sediment moves along the coast by repeated angled swash and more direct backwash. The direction depends on the prevailing wave approach.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A beach receives 480 tonnes of sediment from updrift transport and loses 350 tonnes by downdrift transport in a month. Find the net sediment change and explain what it suggests.
Give me a hint
Subtract the outgoing amount from the incoming amount.
Compare my reasoning
- Net change = 480 − 350 = 130 tonnes.
- The budget is positive for this period.
- It suggests accumulation, if other inputs and losses are negligible.
The beach gained a net 130 tonnes in the simplified sediment budget. Other sources, offshore losses and storm events may change the real balance.
Look for these in your work
- Direction of subtraction correct
- Net amount correct
- Limitation stated
A coastal authority is choosing between a sea wall and mangrove restoration for a low-lying settlement. Compare protection, cost/space and ecological effects.
Give me a hint
Consider immediate engineered protection versus living coastal systems and the local setting.
Compare my reasoning
- A sea wall can reduce wave attack locally but may be costly and alter beach sediment.
- Mangroves can dissipate some wave energy and provide habitat, but need suitable conditions and space to establish.
- Compare maintenance, settlement exposure, ecosystem benefits and effects on neighbouring coasts.
A sea wall may give more immediate engineered protection to a fixed settlement, while mangroves can provide habitat and coastal buffering where they can thrive. Both require site-specific evidence about cost, space, maintenance and impacts elsewhere.
Look for these in your work
- Both options explained
- Coastal and ecological impacts considered
- Conclusion tied to site evidence
A tropical storm affects two coastal districts with similar wind speeds but very different losses. Give three factors that could explain the difference and one way to reduce future risk.
Give me a hint
Separate exposure, vulnerability and preparedness from the storm hazard itself.
Compare my reasoning
- One district may have more people and buildings in the surge zone.
- Building quality, evacuation access and warning coverage may differ.
- Risk can be reduced through forecasting, evacuation plans, resilient shelters or land-use planning.
Losses may differ because exposure, building vulnerability and preparedness differ even when wind speed is similar. Better warning and evacuation or safer land-use planning can reduce risk, but do not remove the hazard.
Look for these in your work
- Three risk factors distinguished
- Hazard and impact not conflated
- Risk-reduction measure appropriate
Common mistakes
- Using corrosion when the process is corrasion
- Saying a groyne protects the whole coast without considering sediment movement
- Treating a storm's hazard as the same as its impacts
- Assuming all reefs and mangroves are in the same condition
What can you explain now?
Why can a groyne reduce beach loss on one side but worsen erosion farther along the coast?
Compare with the explanation
It traps sediment moving by longshore drift, leaving less material for downstream beaches
The structure changes sediment supply along the same coastal system.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
How does longshore drift move sediment, and why can a coastal defence shift risk to a neighbouring place?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.