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Edexcel IGCSE Geography
River Enquiry Skills
The Big Idea: A good river fieldwork enquiry is a full story — you collect real data (primary) and background data (secondary), present it properly on graphs, analyse it with maths like the mean, spot and explain the weird results (anomalies), reach a conclusion, and then honestly judge how good your whole investigation really was.
Quick Summary
Primary data = data you collect yourself in the field (e.g. river width, depth, velocity).
Secondary data = data collected by someone else (e.g. Environment Agency discharge records, OS maps, Met Office rainfall).
Different data types suit different graphs: line graphs for cross-sections, bar graphs to compare sites, scattergraphs to show relationships between two variables.
Quantitative data (numbers) gets analysed using statistics — most commonly the mean.
Qualitative data (photos, field sketches) is analysed by annotation — labelling what you see and explaining why it looks that way.
An anomaly is a result that doesn't fit the pattern — you need to spot it AND explain a plausible cause.
A conclusion says whether your hypothesis was proved or disproved, using the data as evidence.
An evaluation honestly judges the whole enquiry — collection, analysis, reliability — and says what you'd change next time.
1. Presenting Your Data
Primary Data — What YOU Collected
Primary data is any data you personally went out and measured during your river fieldwork — things like river width, depth, velocity (speed of flow), or bedload size. Because you're the one who collected it, you're also responsible for presenting it clearly and accurately.
Think of it like being a scientist writing up an experiment: the raw numbers on their own don't tell a story. A graph turns a boring table into something you (and an examiner) can instantly interpret — "oh, the river gets deeper downstream" jumps out at you from a line graph in a way it never would from a table of five numbers.
Which Graph For Which Job?
Line graph → river cross-sections (shape of the channel)
Bar graph → comparing values between different sites
Scattergraph → relationship between two variables (e.g. width vs discharge)
In plain English: use a line when you're tracing a shape (like the riverbed), use bars when you're comparing separate things side by side, and use dots (scattergraph) when you want to know if two things are connected — like whether a wider river also has more discharge.
Why a scattergraph specifically?
A scattergraph is the only graph type here that can show a relationship between two data sets. If you plot river width on one axis and discharge on the other, and the dots trend upwards, that's evidence discharge increases as the river gets wider — a classic river enquiry finding (linked to the Bradshaw Model).
Worked Example — Completing a Bar Graph
A float was timed travelling between two points on a river. Here's the data collected by a group of students:
Sample
Time taken (seconds)
1
21.1
2
16.0
3
14.1
4
15.0
5
35.0
→ Samples 2, 3 and 5 were already plotted on the bar graph — you had to add bars 1 and 4.
→ Bar 1 needed to reach between 21 and 22 seconds on the y-axis (each small square = 1 second).
→ Bar 4 needed to sit exactly on the 15-second gridline.
→ Both new bars had to match the same width as the existing bars — mark-schemes penalise mismatched bar widths even if the height is correct.
Practice Question 1
Looking at the data table above, which sample number produced the anomalous (odd-one-out) result, and why does it stand out?
Practice Question 2
Suggest one explanation for why sample 5's float took so much longer to travel between the two points.
Secondary Data — What Someone Else Collected
Secondary data is any information used in your enquiry that wasn't collected by you. It matters because primary data alone rarely tells the full picture — secondary data gives you context (was there a storm that day? has the river always looked like this?) and helps you plan (where exactly are your sample sites?).
Useful Secondary Sources for a River Enquiry
Environment Agency discharge data · Met Office rainfall data · Old photographs of the site · Newspaper articles/websites · Ordnance Survey maps · Geology maps · Aerial photographs
Each one answers a different question: discharge data tells you what "normal" flow looks like so you can spot unusual conditions; rainfall data tells you if recent weather affected your results; OS maps help you identify and justify your sample site locations; geology maps explain rock type, which affects erosion; aerial photos reveal how the channel path has changed over time.
Worked Example — Justifying Secondary Data (4 marks)
Q: Describe two sources of secondary data that might be useful when planning a river channel enquiry.
1Environment Agency discharge data — gives information about the river's normal flow, so you can tell if the day you did fieldwork was typical or unusual.
2Met Office rainfall data — gives information about any weather events that might have impacted the data you collected (e.g. heavy rain before your visit raising water levels).
Notice the pattern: 1 mark for naming the source, 1 mark for explaining what it actually tells you. Never just list sources — always say why each one is useful.
Common Mistake
Students often name a secondary source correctly (e.g. "Ordnance Survey map") but forget to explain why it's useful. Naming alone only earns half the marks — always pair the source with its purpose.
2. Analysing & Interpreting the Data
Statistical Analysis — The Mean
Once your data is collected and presented, it needs analysing — turning raw numbers into a meaningful summary statistic. River data like width, depth, and velocity is quantitative (numerical), so the go-to tool is the mean (the mathematical average).
Why bother with a mean at all? Because a single measurement can be misleading — maybe the float got caught on a rock that one time, or the tape measure slipped. Averaging several readings smooths out these one-off errors and gives you a more reliable, representative figure to work with.
The Mean Formula
Mean = (Sum of all values) ÷ (Number of values)
In plain English: add up every measurement you took, then divide by how many measurements there were. That single number represents the "typical" value for that site.
Worked Example — Calculating the Mean (2 marks)
Q: Calculate the mean time taken for the float to travel from site A to site B, to 1 decimal place.
Sample
Time (seconds)
1
12.5
2
16.2
3
18.1
4
20.3
5
35.0
Step 1 Add all the values: 12.5 + 16.2 + 18.1 + 20.3 + 35.0 = 102.1
Step 2 Divide by the number of values (5): 102.1 ÷ 5 = 20.42
Step 3 Round to 1 decimal place: 20.4 seconds
Rounding Rule — Don't Lose Easy Marks
Look at the digit after the decimal place you're rounding to.
• If it's 5 or higher → round UP (e.g. 10.15 → 10.2)
• If it's 4 or lower → round DOWN (e.g. 10.13 → 10.1)
Always show your full working — writing out the addition and division is usually worth its own mark, separate from getting the right final answer.
Practice Question 3
A student measures river depth (in cm) at five points across a channel: 24.6, 31.2, 29.8, 27.1, 26.3. Calculate the mean depth to 1 decimal place, showing your working.
Analysing Photographs & Field Sketches
Not everything in a river enquiry is a number. Photographs and field sketches give you qualitative analysis — a way of interpreting what a landform looks like and explaining why it formed that way. In an exam, you might be shown a photo of a waterfall and asked to annotate or interpret the labels already on it.
The skill here is linking what you can see to the geographical process that caused it. For example, a photo of a waterfall might show:
Hard, resistant rock at the top — erodes slowly, creating an overhang.
Softer, less resistant rock underneath — erodes more quickly, undercutting the hard rock above.
A plunge pool at the base — formed by abrasion (rocks grinding the bed) and hydraulic action (force of falling water).
A steep-sided gorge — formed as the waterfall gradually retreats upstream over time.
Exam Skill
When annotating a photo, don't just label what something is (e.g. "plunge pool") — explain the process that formed it (e.g. "formed through abrasion and hydraulic action"). Description gets you partial marks; explanation gets you full marks.
3. Conclusion & Evaluation
Writing a Conclusion
A conclusion pulls everything together. Once your data has been collected, presented, and analysed, you use it as evidence to decide whether your original hypothesis (your prediction) was proved or disproved. This is not a guess — it must be directly backed by the specific numbers or patterns you found.
A strong conclusion also identifies and explains any anomalies — results that break the expected pattern. Common river anomalies include:
Depth or width unexpectedly decreasing with distance downstream at one site (when you'd normally expect it to increase).
Velocity unexpectedly decreasing at a particular site.
Anomalies might be genuine one-off events, or they might be the result of incorrect recording or human error when reading equipment — either way, a good conclusion acknowledges them rather than ignoring inconvenient data.
Writing an Evaluation
The evaluation is the final, and often trickiest, part of a river enquiry. Here you step back and honestly judge how successful the whole investigation was — not just what you found, but how well you found it, and what you'd change if you did it again.
Four Questions Every Evaluation Should Answer
1. What went well — were results accurate and valid?
2. Is the enquiry reliable — could it be repeated with the same results?
3. What could have been improved?
4. What would you do differently if you repeated it?
Think of it as writing an honest report card for your own investigation — celebrate what worked, but be genuinely critical about what didn't, and always give a specific fix, not just "be more careful."
Worked Example — 8-Mark Evaluation Question
Q: Evaluate how successful your chosen data analysis methods were in answering your geographical enquiry question.
A top-level answer makes a clear judgement and backs it up with specific examples covering:
→Equipment issues — was there faulty equipment, or errors reading the measurements? How did this affect your ability to answer the enquiry question?
→Enquiry design issues — were the sampling methods appropriate? Were more sample sites needed? Would a different technique or extra equipment have worked better?
→Analysis method issues — was the mean (or another method like best-fit lines) the right choice? Were there better alternatives?
→Reliability — could the study be repeated and get the same results?
The mark scheme rewards depth and specificity linked directly to your own enquiry — generic statements like "we could have been more careful" score poorly compared to "the float sometimes snagged on overhanging vegetation at site 3, which artificially increased our travel times."
Practice Question 4
A student's stopwatch readings were inconsistent because different group members started and stopped the timer at slightly different moments. Suggest one way this issue with the enquiry design could be improved next time.
What To Memorise
Primary Data
Data collected by the student themselves during fieldwork (e.g. width, depth, velocity).
Secondary Data
Data not collected by the student — e.g. Environment Agency, Met Office, OS maps, geology maps.
Line Graph
Best for river cross-sections — shows the shape of the channel.
Bar Graph
Best for comparing values between different sites.
Scattergraph
Best for showing the relationship between two variables, e.g. width and discharge.
Mean Formula
Sum of all values ÷ number of values. Always show working and round correctly.
Anomaly
A result that doesn't fit the pattern of the rest of the data set — must be identified AND explained.
Qualitative Analysis
Interpreting photos/field sketches by linking what's visible to the process that formed it.
Conclusion
States whether the hypothesis was proved or disproved, using data as evidence.
Evaluation
Judges success, reliability, and what would be improved or done differently next time.
Concepts Checklist
Exam Tips & Common Mistakes
1
Match the graph style exactly. If you're completing an unfinished graph, use the same bar width, line style, and shading conventions as the data already plotted — inconsistency loses marks even if your numbers are right.
2
Always show your working for the mean. Writing out the full addition and division is usually worth its own mark, separate from the final rounded answer.
3
Round correctly, every time. Digit 5 or higher → round up. Digit 4 or lower → round down. Double-check you rounded to the number of decimal places actually asked for.
4
Never just name a secondary data source — explain its purpose too. "Environment Agency discharge data" alone is half an answer; "...gives information about normal flow" completes it.
5
Anomaly questions come in pairs. First identify which result is anomalous, then explain why it might have occurred — both parts are usually needed for full marks.
6
The 8-mark evaluation question rewards depth, not breadth. A detailed answer covering equipment, design, and analysis issues — with specific examples from your own enquiry — beats a shallow answer that lists many generic points.
7
Always finish an evaluation with a clear judgement. Don't just list pros and cons — explicitly state how successful you think the enquiry was overall, and whether the outcomes are reliable enough to be repeated.