中文（繁體）
中文（简体）
English
S5 Geography Rivers, Paper 4: landforms and human activity
S5 Geography Rivers, Paper 4: landforms and human activity
Paper 4 covers gradient, waterfalls and flood plains, then calculates discharge, catchment runoff, flood peak reduction and velocity at a narrowing, and interprets reservoir and runoff coefficient figures.
Focus Gradient is fall over length, discharge is cross section times velocity, runoff volume is area times rainfall times the coefficient, and a fixed discharge speeds up where the section narrows.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 25 |
| Difficulty mix | Foundation 4 · Intermediate 3 · Challenge 2 · Error redo 1 |
| Chapter | Chapter: S5 Geography: Rivers |
| Level | S5 |
02 Questions (10 items)
- FoundationA river runs 180 km with a fall of 720 m. What is its average gradient in metres per kilometre?
- FoundationHow does a waterfall normally form?
- FoundationHow is a flood plain formed?
- FoundationIn which course of a river is deposition strongest?
- IntermediateA channel is 18 m wide and 2.5 m deep with a velocity of 1.6 m per second. What is the discharge?
- IntermediateA catchment of 60 square kilometres receives 120 mm of rain that all runs off. What is the runoff volume?
- IntermediateA reservoir cuts the flood peak from 120 cubic metres per second to 78. By what percentage is the peak reduced?
- ChallengeA channel narrows from 24 m to 8 m while discharge stays at 96 cubic metres per second and the depth there is 2.5 m. What is the velocity?
- ChallengeA basin of 350 square kilometres has 2200 mm of rain a year and a runoff coefficient of 0.35. What is the annual runoff volume?
- Error redoError: a student says erosion is strongest in the lower course. What is correct?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | 4 m per km | Gradient is fall over length, and 720 divided by 180 is 4. |
| 2 | Hard rock caps softer rock, the soft layer is eroded into a step, and the river plunges over it | Rock of differing resistance creates the step, and as the face retreats the fall slowly migrates upstream. |
| 3 | Flood water spills over the banks, slows sharply and drops its fine sediment on both sides | Each flood lays down a thin sheet of silt, and repeated layers build a flat fertile plain. |
| 4 | The lower course, where velocity and carrying power are lowest | The slower the flow the finer the load it can hold, so sand and silt settle in the lower course and at the mouth. |
| 5 | 72 cubic metres per second | The cross section is 18 times 2.5, which is 45 square metres, and times 1.6 gives 72. |
| 6 | 7 200 000 cubic metres | Sixty square kilometres is sixty million square metres, and times 0.12 m gives seven million two hundred thousand cubic metres. |
| 7 | Reduced by 35 per cent | The difference is 42, and 42 over 120 is 0.35, so the peak is a third lower and flood risk falls. |
| 8 | 4.8 m per second | The section is 8 times 2.5, which is 20, and 96 over 20 is 4.8, so this reach erodes strongly. |
| 9 | 269 500 000 cubic metres | Three hundred and fifty square kilometres is 350 million square metres, times 2.2 m gives 770 million, and 0.35 of that is 269.5 million. |
| 10 | Erosion is strongest upstream through downcutting and headward erosion, while the lower course is dominated by lateral erosion and deposition | Steep fast headwaters spend their energy cutting down, while the gentle lower course mostly transports and finally deposits. |
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.
Book an S5 Geography tutorTutor 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.
