Physical Landscapes in the UK: River Landscapes — AQA GCSE Geography
Rivers shape the land as they flow from source to mouth, creating distinctive landforms and flood risks that must be managed.
The long profile and processes
A river's long profile shows how it changes from source to mouth. The cross profile changes too — narrow and steep in the upper course, wide and flat in the lower course.
River processes are:
- Erosion — hydraulic action, abrasion, attrition and solution. Vertical erosion dominates upstream; lateral erosion dominates downstream.
- Transport — traction, saltation, suspension and solution.
- Deposition — material is dropped when the river loses energy (e.g. on the inside of a bend or at the mouth).
Landforms
- Upper course: interlocking spurs, waterfalls and gorges.
- Middle course: meanders (with river cliffs and slip-off slopes) and ox-bow lakes.
- Lower course: floodplains, levées and estuaries.
You should be able to explain how each forms and identify them on OS maps and photographs.
Flooding and management
Flood risk is increased by physical factors (precipitation, geology, relief) and human factors (urbanisation, deforestation). Hydrographs show how a river responds to rainfall (lag time, peak discharge).
Management strategies:
- Hard engineering — dams and reservoirs, straightening, embankments, flood relief channels. Effective but expensive and can have environmental costs.
- Soft engineering — flood warnings, floodplain zoning, planting trees (afforestation), river restoration. Cheaper and more sustainable.
A case study of a UK flood management scheme should give the causes, the strategy and the social, economic and environmental issues.
Exam tips
- Link processes (erosion, transport, deposition) to course of the river.
- Learn the formation of waterfalls, meanders, ox-bow lakes and floodplains/levées.
- Interpret hydrographs (lag time, peak discharge).
- Compare hard vs soft flood management and use a named case study.