Question 1 Report
Fig. 1 shows a desert road crossing a wadi in Oman. It is dry for most of the year, but local residents reported that it filled rapidly after a storm in the mountains. Table 1 gives rainfall measured at two stations during the same storm. The road engineer is assessing flash-flood risk.
| Station | Rainfall in 2 hours (mm) | Distance upstream (km) |
|---|---|---|
| Mountain station | 57 | 24 |
| Wadi crossing | 6 | 0 |
(a) Which station recorded the greater rainfall total? [1]
(b) Outline why the road at the wadi crossing may flood even when little rain falls there. [2]
(c) Draw a warning sign position on Fig. 1 where drivers should stop before entering the channel. [1]
(a) Mountain station [1] (b) Heavy rain falls upstream/in the mountains [1]; runoff travels down the wadi and concentrates at the crossing [1]. (c) Warning sign placed on either road approach before the low channel crossing [1]
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