The investigation you have been given
Nothing at all. The fieldwork question is on this page, and everything after it assumes you know what the investigation is and why it counts as geography.
- The fieldwork question written in your own words
- One or two sub-hypotheses, each with its null
- The syllabus topic and sub-topic you are investigating
- A prediction you can defend, and the reasoning behind it
Everyone has the same question. Almost none of the marks are for the question.
You were handed a fieldwork question and you will collect the data as a group. That is normal, it is allowed, and it is what the IB expects of a class doing river fieldwork together. It also means the parts that make your report yours are further down than you think.
How do the fluvial characteristics of a river change with distance from the source?
That is the question, word for word, and every one of you has it. Notice that it says a river: the question is written to fit whichever river a class studies, and yours answers it for the Asse at Nyon. Your report has to state it, and Criterion A (Fieldwork question and geographic context) also wants a precise location attached to it, which is what step 2 is for.
Read it once more before you go on, because the words in it decide a lot. Fluvial characteristics is what you are measuring. Change is what you are looking for. Distance from the source is your x-axis, every time, and it is the reason plotting against site number instead is the commonest mistake in this investigation.
| Criterion | Marks | Shared with the class, or yours? |
|---|---|---|
| A · Fieldwork question and geographic context | 3 | Shared question. Your map, your framing |
| B · Method(s) of investigation | 3 | Methods you are given. Your justification of them |
| C · Quality and treatment of information collected | 6 | Yours |
| D · Written analysis | 8 | Yours |
| E · Conclusion | 2 | Yours |
| F · Evaluation | 3 | Yours |
Nineteen of the twenty-five marks are earned after the fieldwork day. Everything from Criterion C (Quality and treatment of information collected) to Criterion F (Evaluation) is written alone, from a dataset everybody shares. Two people can walk away from the same river with the same readings and end up several grades apart.
So the day at the river is not the investigation. It is the shortest part of it.
Everything below is how we suggest you actually do it.
Start by putting the question in your own words
The question is: how do the fluvial characteristics of a river change with distance from the source? Before you do anything else, rewrite it as a sentence you would say out loud. If you cannot, you do not yet know what you are measuring.
"Fluvial characteristics" is doing a lot of quiet work in that sentence. It means the measurable properties of the channel and its flow, width, depth, wetted perimeter, gradient, velocity, the size and shape of the load. Not the scenery, not the land use, not the wildlife.
The question also tells you what your x-axis is. Distance from the source, in metres, for every single graph. Not site number. Site number is an arbitrary label; distance is the variable the question actually asks about, and using site number quietly throws away the spacing between your sites.
Writing the question at the top of page one and never mentioning it again. Criterion D (Written analysis) asks whether your analysis allows the question to be answered, and Criterion E (Conclusion) whether your conclusion answers it.
A report that describes eight variables beautifully and never returns to "so, how do the characteristics change with distance?" cannot reach the top band of either.
Write one or two sub-hypotheses, and their nulls
The fieldwork question is too big to answer in one go, so you break it into sub-hypotheses: one or two testable claims that together add up to an answer. Choose them for what you can graph, map and test, not for how many variables you can cram in.
A usable hypothesis does three things. It is directional (it says which way, not just "there is a relationship"), it links two measurable variables, and it is a claim that could turn out to be false. "Velocity will increase with distance from the source" qualifies. "The river changes downstream" does not: nothing could contradict it.
Write the null hypothesis alongside each one; the claim that there is no relationship between the two variables. It costs a line, and it is the thing a statistical test lets you reject, so you need it the moment you run one. Step 4 decides whether you will, because a test is optional here, but a hypothesis sharp enough to have a null is worth writing either way.
"The River Asse follows the Bradshaw model."
This is several claims at once, some of which will hold and some of which will not, so no result can confirm or contradict it cleanly.
"Cross-sectional area increases with distance from the source." Null: there is no relationship between cross-sectional area and distance from the source.
One relationship, two measured variables, a stated direction, and a null sharp enough to put a test against if you choose to run one.
Bradshaw describes. It does not explain
The Bradshaw model is the standard summary of what happens downstream: discharge, width, depth and velocity increase; bedload size, channel roughness and gradient decrease. It is a useful shared picture and you should refer to it.
But it is a summary of a tendency, not a cause, and it is a model at best. River velocity does not increase because Bradshaw says so. It increases because the channel gets larger and smoother relative to its perimeter, so proportionally less of the water is in contact with the bed and banks, so proportionally less energy goes into friction. Bradshaw is the picture of that result.
This distinction is worth more than it looks. The top band of Criterion D (Written analysis) wants patterns explained and linked to geographical theory. "Velocity increased, as the Bradshaw model predicts" is a description with a reference attached. "Velocity increased where hydraulic radius rose, because proportionally less water was in contact with the bed and banks" is an explanation, and the figures that go in it are yours.
It is worth knowing what you are citing. The diagram first appears in M. J. Bradshaw’s 1978 school textbook The Earth’s Changing Surface. Bradshaw was a senior lecturer at a teacher-training college in Plymouth, and the illustration was drawn to teach downstream change, not to report a study.
It is also second-hand. Bradshaw simplified a model published a year earlier by the fluvial geomorphologist Stanley Schumm in The Fluvial System (1977), which in turn drew on a run of research papers. The genuinely empirical ancestor is Leopold and Maddock’s 1953 work on hydraulic geometry for the US Geological Survey, which expressed width, depth and velocity as measured power functions of discharge.
So the thing in your textbook is a teaching diagram two steps removed from the research, and it is drawn as a set of wedges with no axes, no units and no data on it. Nothing about it can be measured, which is why “the results fit the Bradshaw model” is a sentence that cannot really be true or false.
Most people assume a river runs fastest in its steep upper course, where it looks and sounds fastest. It usually does not.
Upstream the channel is small, shallow and full of boulders: a large wetted perimeter relative to a small cross-sectional area, so a low hydraulic radius, and a rough bed. Most of the energy is spent on friction and turbulence. Downstream the channel is larger and smoother, hydraulic radius rises, and mean velocity increases despite a gentler gradient.
If you can explain that properly, you have shown exactly the understanding Criterion D (Written analysis) rewards.
Name the syllabus link, then describe it
The investigation sits in the optional theme Freshwater, drainage basins, in the sub-topic on drainage basin hydrology and geomorphology. Specifically: river discharge and its relationship to channel characteristics and hydraulic radius, and the river processes of erosion, transportation and deposition.
Naming it is worth a mark. Describing the link is worth the band above, and it takes one more sentence: say what about that syllabus content your fieldwork examines, and why measuring these eight variables at these sites tests it.
You have roughly 150 words here and another 150 in step 2, for three marks. It is the tightest section in the report relative to what it has to cover, which is why the checklist below is about having the material ready rather than about writing it beautifully.
It can explain hydraulic geometry, the Bradshaw model or why hydraulic radius matters, when a textbook explanation has not landed. Reading around your topic is exactly what Level 1 is for.
It cannot write your hypotheses. A hypothesis is a claim you are willing to be wrong about, and the reasoning you give for it in step 6 is what the marks are actually for.
Ready for step 2?
0 of 8An untickable box is not a mark against you; it is the next thing to go and do. Most of these take minutes, and they are the cheapest marks in the report.
Step 2 takes the other half of Criterion A (Fieldwork question and geographic context): where this river is, why it is a sensible one to investigate, and the locational map that the mark scheme names explicitly.
Anything marked “our river” is specific to the fieldwork we do together on the River Asse at Nyon: the sites, the equipment and the way we collect the data. Site coordinates and altitudes are from our own fieldwork records and the exact list can change from year to year, so check them against the sheet you are given on the day. Photographs are the author’s own, taken at the river.