Beach features

Question 1

Beach berms

Answer 1

Run parallel to the shore and are caused by the deposition of beach material in swash, usually forming on the upper part of the foreshore, and over the backshore during severe events. Berms are generally created by smaller waves which have less energy so the material is smaller. Smaller ridges develop at the position of the mean high tide mark resulting from deposition at the top of the swash.

Question 2

Beach cusps

Answer 2

Small and temporary semi-circular depressions formed by a collection of waves reaching the same point. The sides of the cusp channel the incoming swash into the centre of the depression and produces a stronger backwash which drags material down the beach from the centre of the cusp.

Question 3

Runnel

Answer 3

Extensive dips that form parallel to the shore line in the foreshore zone. They are disrupted by channels that help to drain the water down the beach.

Question 4

Backshore

Answer 4

Part of the beach between the foreshore and coastline. It is dry and without vegetation under normal conditions and often characterised by berms. The backshore is only exposed to waves under extreme events.

Question 5

Beach Morphology

Answer 5

The shape and form of beaches and their features.

Question 6

Foreshore

Answer 6

The area of a shore that lies between the average high tide mark and the average low tide mark.

Question 7

Littoral Zone

Answer 7

Boundary between land and sea. It extends from the high-water mark, which is rarely inundated, to shoreline areas that are permanently submerged.

Question 8

Nearshore

Answer 8

Zone extending seaward from the low water line well beyond the breaker zone; it defines the area influenced by the nearshore currents. It extends somewhat further seawards than the littoral zone.

Question 9

Offshore

Answer 9

Situated at sea some distance from the shore.

Question 10

Constructive waves

Answer 10

Waves which have a strong swash and weak backwash (which soaks into the sand, absorbing wave energy). They are characterised by a long wavelength, long period and low amplitude. These waves are common in the summer and lead to the development of beaches (beach berms). They are less frequent at 6-8 waves per minute.

Question 11

Destructive waves

Answer 11

Waves which have a weak swash and strong backwash (which has less time to soak into the sand, carrying material down the beach). They are characterised by a short wavelength, short period and high amplitude. These waves are common in the winter and lead to the erosion of beaches (to produce a steep beach profile with breakpoint bars). They are more frequent at over 12 waves per minute and attack the base of cliffs.