Question 1 Report
A coastal ranger recorded changes at a shingle beach beside a small harbour. Fig. 1 is a plan view showing groynes, the direction of prevailing waves and areas where sediment has built up. The ranger wants to explain why the beach has become narrow on one side of the harbour entrance. Use the shown figure in your answer.
(a) Which direction does longshore drift move sediment in Fig. 1? [1]
(b) Draw arrows on a copy of the figure to show the zig-zag movement of a pebble moved by longshore drift. [2]
(c) Outline one likely effect on the beach immediately downdrift of the groynes. [2]
(a) Along the shore in the direction produced by the angled wave approach, from the updrift side towards the sediment-poor side [1] (b) Award [1] for swash arrow at an angle up the beach; [1] for backwash arrow straight downslope, producing an overall alongshore zig-zag [1] (c) Less sediment reaches the downdrift beach [1]; so it becomes narrower / erosion is more likely [1]
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