River landforms: erosion, transport and deposition
Build process sequences for valleys, waterfalls, meanders and floodplains, then test them against relief and sediment evidence.
Follow erosion and transport
Hydraulic action and abrasion can remove bed or bank material; attrition reduces transported fragments and solution carries dissolved material. Traction, saltation and suspension describe different transport pathways.
Vertical and lateral erosion shape channels differently. Downstream patterns reflect gradient, discharge, sediment and geology; a long profile is not a universal timetable for every river.
Worked example
A fictional reach falls 30 m over 6 km. Convert distance to 6,000 m: gradient is 1:200. This describes the reach’s average slope, not its erosion rate.
Common mistake: Gradient alone does not determine erosion; discharge and sediment also matter.
Explain waterfall retreat and meander change
Where resistant rock overlies weaker material, differential erosion can form a step. Undercutting, plunge-pool erosion and collapse can cause retreat, leaving a gorge; actual structure may be more complex.
In a meander, flow and channel geometry promote outer-bank erosion and inner-bank deposition. A neck cutoff can leave an oxbow lake as the abandoned loop becomes separated.
Worked example
Fictional bend surveys show an outer bank moving 4 m outward and an inner bank gaining a 2 m strip. These observations need common baselines and dates before inferring migration.
Common mistake: An oxbow lake requires a cutoff sequence, not erosion on one bank alone.
Connect floodplain form and flood processes
Repeated overbank flow can deposit sediment on a floodplain. Natural levees may form where coarser sediment settles near the channel as water loses velocity.
A floodplain combines long-term deposition with channel movement and human alteration. Flood risk depends on hazard, exposure and vulnerability; a landform name does not provide an event probability.
Worked example
A fictional floodplain cross section ranges from 12 to 15 m elevation, while the channel bed is 8 m. These heights require a common datum and do not supply the flood-water level.
Common mistake: A levee can reduce some flooding while retaining overtopping or failure risk.
Contours and relief · Landscape cross sections · Source evaluation
Try a different resource
Landscape cross sections
The profile joins six measured points with straight segments. Horizontal units are kilometres and vertical units are metres. The drawn slope angle is exaggerated by these different scales.
Scroll the diagram sideways to see the full resource.
| Distance (km) | Height (m) |
|---|---|
| 0 | 20 |
| 1 | 320 |
| 2 | 620 |
| 3 | 920 |
| 4 | 620 |
| 5 | 20 |
Resource description
0 km along the transect: 20 m above datum; 1 km along the transect: 320 m above datum; 2 km along the transect: 620 m above datum; 3 km along the transect: 920 m above datum; 4 km along the transect: 620 m above datum; 5 km along the transect: 20 m above datum
Write an explanation
Check your answer
- Explain connected stages and locations.
- Use geological or flow conditions.
- Interpret relief and sediment evidence.
- Use a taught river-valley landform example; linked flood projects alone do not complete it.
Practise and review a written answer
Case studies
Carlisle during Storm Desmond · Slowing the flow at Pickering
These pages provide selected evidence. Check the whole case requirement with your teacher.
Read further
- www.aqa.org.uk — source or course reference
- www.aqa.org.uk — source or course reference
- qualifications.pearson.com — source or course reference
- www.sqa.org.uk — source or course reference
- www.sqa.org.uk — source or course reference
- qualifications.pearson.com — source or course reference
- www.ocr.org.uk — source or course reference
- www.ocr.org.uk — source or course reference
- www.eduqas.co.uk — source or course reference
- www.eduqas.co.uk — source or course reference
Drainage basins as systems · Flood management and residual risk
Course links
AQA GCSE Geography · Pearson Edexcel GCSE Geography B · National 5 Geography · Higher Geography · Pearson Edexcel GCSE Geography A · OCR GCSE Geography A · OCR GCSE Geography B · Eduqas GCSE Geography A · Eduqas GCSE Geography B
Next topics
Rivers and flooding · Water cycles: budgets, residence time and feedback
Selected teaching sequence with fictional worked data. The linked case records supply bounded evidence; they do not satisfy every course case requirement.
Scottish links identify reusable parts of the topic. Scottish landforms, soil, weather and disease requirements need additional course-specific teaching.