A fieldwork team measured beach width at four locations along a resort coast in Barbados. Fig. 1 shows a groyne installed beside one of the measurement site...
Question 1 Report
A fieldwork team measured beach width at four locations along a resort coast in Barbados. Fig. 1 shows a groyne installed beside one of the measurement sites. The team expected longshore drift to transport sand from west to east. Table 1 gives the width of dry beach measured at low tide, in metres, on either side of the groyne.
| Location | Position relative to groyne | Dry beach width (m) |
|---|---|---|
| 1 | West side | 42 |
| 2 | West side | 39 |
| 3 | East side | 18 |
| 4 | East side | 16 |
(a) State the widest dry beach width shown in Table 1. [1]
(b) Describe the difference in beach width on the two sides of the groyne. [1]
(c) Explain how a groyne affects longshore drift. [2]
Answer Details
(a) The widest dry beach width is 42 m. [1]
(b) The west side is much wider than the east side: west-side measurements are 39 to 42 m, compared with 16 to 18 m on the east side. [1]
(c) A groyne is a barrier built across the beach that traps sediment transported by longshore drift. Sand builds up on the updrift side, which here is the west side because sediment is expected to move west to east. Less sediment is then available to continue beyond the groyne, so the downdrift side can be narrower. [2]
Download The App On Google Playstore
Everything you need to excel in your exams
