Coastal Engineering Questions and Answers

Answer: A

The divisions are defined by water level and by wave behaviour rather than by any fixed distance. Each is dominated by a different set of processes and responds on a different timescale. Boundaries move as water level and wave conditions change.

Answer: B

It is where broken waves dissipate their energy as they travel shoreward. Most of the sediment transport along a beach takes place within this comparatively narrow band. Energy dissipation and sediment motion coincide there.

Answer: C

Both are true and the reason gives the two ingredients, and neither alone would move much material. Suspension by turbulence and advection by the current act together to produce the transport. Either alone would move remarkably little material.

Answer: D

It is the most energetic part of the profile per unit area and changes shape rapidly. Its slope adjusts quickly to the prevailing wave conditions and sediment size. It is the most rapidly changing part of the whole profile.

Answer: A

The first two are correct and follow the standard definitions. The third reverses the geometry, since the offshore zone lies seaward of the breakers where waves have not yet broken. The breaker line is the boundary between the two zones.

Answer: B

It is built by the uprush depositing sediment at the limit of its reach. Storm waves cut it back and swell conditions rebuild it over the following weeks or months. The berm crest marks the reach of the ordinary uprush.

Answer: C

Both are true and the reason gives the mechanism, and a storm berm often sits above the ordinary summer berm. The set of berms records the recent history of water levels and wave conditions. Each berm records a particular set of conditions.

Answer: D

Steep short period storm waves carry sand seaward into a bar, flattening the face. The sand is not lost, and long swell waves return it to the beach over the following weeks. The exchange is largely reversible within a season.

Answer: A

Both are true and the reason gives the protective mechanism, and the bar is therefore a self regulating response. Removing it by dredging would expose the beach to the full wave attack. The bar is part of the beach's own defence.

Answer: B

The first two are correct and describe the seasonal cycle. The third is wrong for the ordinary case, since the sand remains within the active profile and returns under milder conditions. Only losses beyond the depth of closure are permanent.