AO3 – There should be clear analysis of the relationships between rainfall in the drainage basin and its impact upon the simulated hydrograph. There should also be data manipulation to support the analysis. The relationship between the simulation and actual hydrograph should also be analysed.

Mark scheme

Level 2 (4–6 marks)

AO3 – Clear analysis of the quantitative evidence provided, which makes appropriate use of data in support. Clear connection(s) between different aspects of the data and evidence.

Notes for answers

AO3

Level 1 responses are likely to simply describe the data without clear attempt to analyse, for instance by manipulating data, identifying relationships and/or spotting trends.

The first round of rainfall appears to make little impact on either the measured or simulated discharge. Rainfall peaks at 2mm and the event appears to last around 4–5 hours. Discharge remains at between 1–2 m³/sec. The simulated discharge appears to show some response to the event with a sharp rise and quick return to below normal baseflow within 4–5 hours. It is the measured flow which shows very little response to the event.
However, by around 6 pm on 14.04.07 there is a very strong and almost immediate increase in discharge. Discharge increases by almost 7 m³ /sec with virtually no build up prior to this. The simulated data shows more of a lag – around 3–4 hours, a sharp increase but a lower peak perhaps up to 1 m³ /sec less. Some may question the reliability of the simulation in predicting the impact of the first event.
The second event appears to start around 6pm on 14.04.07 and last around 10 hours. The lag time is longer for both the measured and simulated discharge. The peak is also lower at around 6.6 m³ /sec. The simulation is even less accurate following the second event. The peak is lower than the measured flow by over 2 m³ /sec and the return to base flow is less pronounced.

Credit any other valid analysis.

Quantitative & Qualitative Skills (AQA A Level Geography)

Topic Questions