Question 11 mark
The hydrograph shows one storm. Take peak rainfall as 12:00, the end of the wettest two-hour period. What is the lag time?
| Category | Discharge (cumecs) |
|---|---|
| 06 | 3 |
| 08 | 3 |
| 10 | 4 |
| 12 | 7 |
| 14 | 15 |
| 16 | 24 |
| 18 | 21 |
| 20 | 15 |
| 22 | 10 |
| 00 | 7 |
| 02 | 5 |
| 04 | 4 |
Water and carbon cycles · AQA, Edexcel, OCR
Drainage basins and storm hydrographs
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Question 21 mark
Using the hydrograph, by how much does discharge rise above its 06:00 level at the peak?
| Category | Discharge (cumecs) |
|---|---|
| 06 | 3 |
| 08 | 3 |
| 10 | 4 |
| 12 | 7 |
| 14 | 15 |
| 16 | 24 |
| 18 | 21 |
| 20 | 15 |
| 22 | 10 |
| 00 | 7 |
| 02 | 5 |
| 04 | 4 |
Question 31 mark
On the hydrograph, why is the falling limb gentler than the rising limb?
Question 41 mark
A large housing estate is built across the lower half of this catchment. How is a storm hydrograph from the same rain likely to change?
Question 51 mark
Two basins have the same area and rock. Basin A is circular; Basin B is long and thin. Which is likely to have the shorter lag time?