Fig. 1 shows a cross-section drawn during an inspection of a concrete sea wall at a resort beach. The wall has a curved upper face and a drainage outlet. At...
Question 1 Report
Fig. 1 shows a cross-section drawn during an inspection of a concrete sea wall at a resort beach. The wall has a curved upper face and a drainage outlet. At high tide, steep storm waves strike the wall and water runs back across the sand. The council plans to renew the structure because hotels and a railway lie immediately behind it. Use the coastal study figure to consider both the protection supplied and the impacts produced by this hard-engineering method.
(a) Identify the hard-engineering structure in Fig. 1. [1]
(b) Describe how its curved face changes the movement of wave water. [2]
(c) State two reasons why drainage is needed behind or through the wall. [2]
(d) Explain three disadvantages of relying only on this type of coastal defence at the resort. [7]
Answer Details
(a) The hard-engineering structure is a sea wall. [1]
(b) Its curved face reflects or deflects wave water upward and back towards the sea. This reduces direct overtopping of land behind the wall. [2]
(c) Drainage removes rainwater, prevents water pressure building behind the wall, reduces saturation and instability of ground, and lets water escape after overtopping. Any two gain credit. [2]
(d) Sea walls are expensive to construct and maintain, especially after storms. Reflected wave energy can scour the beach at the wall base, narrowing the beach. The structure may be visually intrusive or restrict beach access, affecting tourism. Finally, if it fails or is overtopped, severe flooding can occur because valuable hotels and railway infrastructure are concentrated behind it. Any three developed disadvantages gain credit. [7]
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