Beach Erosion and Protection Questions and Answers

Answer: A

Correct answer: 1 and 2 only

Statements 1 and 2 are correct: a beach cut back by a single storm normally rebuilds over the following calmer months, and a trend that persists across years means more sediment is leaving the frontage than arriving. Statement 3 confuses an event with a trend - the whole difficulty of diagnosing erosion is that a bare beach after a storm looks alarming and may mean nothing at all.

Answer: B

Separating the natural drivers from the human ones matters greatly for choosing a response. Only some of them can be addressed at their source, and the rest must simply be accommodated instead. Sea level rise is not amenable to local intervention.

Answer: C

A fillet of sand builds against the updrift arm while the coast beyond receives nothing at all. Relocating the difficulty rather than removing it is the standing objection to any barrier placed across the drift. Bypassing is the usual compensating measure.

Answer: D

Correct answer: 1 and 2 only

Statements 1 and 2 are the two faces of the same mechanism: what the groyne field holds on its updrift side is exactly what fails to reach the frontage beyond. Statement 3 is wrong and is the central misunderstanding about groynes - they redistribute the sediment already moving along the coast and add nothing to the littoral system. Only nourishment does that.

Answer: A

The categories differ in whether they resist the process or accommodate it. Shoreline management plans consider all of them for each frontage in turn before a policy is assigned. Doing nothing is a legitimate option to appraise.

Answer: B

The ratio multiplies the required volume to allow for the anticipated losses. A ratio approaching two is a strong signal that a better borrow source should be sought. A poor match costs more in the end than a distant one.

Answer: C

Both are true and the reason gives the advantage, and the profile also stands slightly steeper. The gain must be set against the usually higher cost of coarser material. Grain size is the first thing checked in a borrow study.

Answer: D

Correct answer: is generally regarded as lost to the active beach profile

The depth of closure is the seaward limit beyond which the profile shows no measurable change from year to year, so sediment placed beyond it is outside the zone the waves rework and will not come ashore on any useful timescale. Placing there is cheaper per cubic metre, since the dredger need not approach the beach, but the sand does not do the job it was bought for.

Answer: A

Correct answer: 1 and 2 only

Statements 1 and 2 set out the trade exactly: sand placed within the active profile joins the beach system, while deeper placement saves money on the dredging but may never reach the shore. Statement 3 is plainly wrong, and placement depth is one of the few decisions in a nourishment scheme that determines whether it works at all.

Answer: B

Berm placement is simpler and gives immediate visible width but redistributes rapidly. Profile placement is closer to the equilibrium shape and settles with less initial loss. Berm placement gives visible width more quickly.