Coastal environments
Connect wave energy, rock and sub-aerial processes to coastal landforms, then assess coral-reef threats and shoreline management.
Exam scope and assessment notes
Cambridge International AS & A Level Geography 9696, 2027–2029 syllabus, Topic 8. Across every topic, practise reading both quantitative and qualitative geographical resources, describing patterns before explaining them, evaluating evidence and producing a structured, supported conclusion. These original explanations and self-checks are independent study support, not Cambridge questions, official marks or grades. Centre-selected named examples and detailed case studies still need course-specific evidence packs. Full timed mock papers, official marking or grade prediction, and human subject-teacher review are not provided. Fieldwork is not assessed in this syllabus, but this site does not collect or supervise primary data.
Before you begin
- Cambridge recommends prior Geography at approximately Cambridge IGCSE or Cambridge O Level. Read the source and its scale before explaining patterns; support evaluation with relevant evidence.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which direction does longshore drift move sediment along a beach?
What you will learn
- Explain wave generation, refraction, coastal erosion, weathering, mass movement, transport and deposition
- Describe erosional and depositional landforms in plan and cross-section
- Explain coral growth conditions, threats and management
- Evaluate hard and soft management for a selected coastline using evidence
Waves and geology set the coastal process context
Fetch and wind influence wave energy. Refraction concentrates energy around headlands and disperses it in bays; swash and backwash shape beaches. Rock type and structure, climate and human activity influence how a coast changes.
Hydraulic action, cavitation, abrasion, corrasion and attrition erode coasts. Freeze–thaw, salt growth, carbonation and solution weather rock above the waterline; rockfalls, landslides and mudflows move material downslope. Sediment is transported by traction, saltation, suspension and longshore drift within a sediment cell.
Landforms record interacting erosion and deposition
Differential erosion on discordant coastlines can create headlands and bays; concordant strata respond differently. Cliffs, shore platforms, caves, geos, arches and stacks form through erosion and collapse. Beaches may be swash-aligned or drift-aligned; spits, tombolos and barrier beaches reflect sediment supply and changing wave direction.
Dune systems, saltmarshes and mangroves are shaped by sediment, vegetation, water and disturbance. Coral requires suitable temperature, light, depth, salinity, oxygenation and limited sediment; symbiotic zooxanthellae support reef growth. Reefs face warming, acidification, storms, pollution and physical damage.
Management choices redistribute risk and benefit
Hard engineering such as sea walls, groynes and breakwaters can protect particular sites but may transfer erosion or interrupt sediment movement. Soft approaches such as beach nourishment, dune restoration, saltmarsh or mangrove conservation work with sediment processes but need space, maintenance and suitable conditions.
Coral management can reduce pollution, anchoring or harvesting pressure and protect reef areas, but local actions cannot remove global warming or ocean acidification. Evaluate the chosen coastline or reef using a named place, affected groups, time period, monitoring and unintended effects.
Sources for this lesson
Pause and explain
Why should a coastal-management evaluation use a sediment-cell scale?
Worked example
A groyne protects the beach immediately updrift, while the downdrift beach narrows. Explain the sediment pathway and one question needed before judging the project.
Show the worked solution
- Longshore drift transports sediment along the coast in the direction set by prevailing wave approach.
- The groyne traps some sediment updrift, so that beach may widen while less sediment reaches downdrift sections.
- Check sediment-cell boundaries, storms, other structures, beach profiles and the protection goal before attributing all change to the groyne.
Answer A groyne can redistribute sediment within a wider cell. Site evidence is needed to assess whether it reduced overall risk or shifted erosion.
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.
Waves approach a beach at 25° to the shoreline and backwash moves downslope at right angles. Describe the net sediment movement and one reason it may vary.
Give me a hint
Separate the oblique swash direction from the perpendicular backwash.
Compare my reasoning
- Swash carries sediment diagonally up the beach.
- Backwash returns downslope roughly at right angles, producing a zigzag net movement along the shore.
- Changing wind and wave direction can alter the net drift over time.
The swash/backwash sequence produces longshore drift; the direction and amount vary with wave approach, tides and storms.
Look for these in your work
- Both movements distinguished
- Net alongshore transport explained
- Variation acknowledged
Explain how a cave, arch and stack may develop on a jointed headland.
Give me a hint
Follow erosion along a weakness and include the effect of collapse.
Compare my reasoning
- Waves exploit joints by hydraulic action and abrasion, enlarging a cave.
- Continued erosion may cut through a narrow headland to create an arch.
- Weathering and undercutting weaken the arch; collapse can leave a stack and later a stump.
Erosion follows weaknesses to form caves and arches; collapse can leave a stack. Rock structure and wave exposure affect the sequence and rate.
Look for these in your work
- Weakness identified
- Erosion process linked
- Collapse sequence completed
A reef tourism area faces warmer seas, sewage runoff and anchor damage. Rank two possible management actions and explain what evidence would test their success.
Give me a hint
Match each action to a pressure and separate local from global causes.
Compare my reasoning
- Wastewater treatment can reduce nutrient and pathogen inputs from land.
- Mooring buoys and visitor zoning can reduce anchor damage in heavily used areas.
- Track water quality, coral cover, bleaching, visitor pressure and enforcement over time; local measures do not remove ocean warming.
Local actions can reduce sewage and physical damage, but reef health also depends on wider thermal stress. Monitor several indicators and compare with a baseline and suitable reference sites.
Look for these in your work
- Action matches pressure
- Global and local causes distinguished
- Evaluation measures named
Common mistakes
- Treating longshore drift direction as fixed at every time and tide
- Naming a landform without explaining the process and geology
- Assuming one structure protects the entire sediment cell
- Confusing coral stress from heat with pollution alone
- Judging management by one beach section without a time series
What can you explain now?
What happens to wave energy as waves refract around an exposed headland?
Compare with the explanation
Energy is often concentrated around the headland
Wave fronts bend as depth changes, commonly focusing erosion on headlands.
After trying it yourself, choose your next review. This is your self-assessment.
Your review choice appears on Today. Sign in to sync it across devices.
Make it stick
Trace one coastal landform from energy and sediment processes, then explain why its management should be judged across a connected coastline.
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.