Types of waves

These are:

• low in height (less than a metre)
• flat and gentle
• have wavelengths up to 100m
• have a long period of 6-8 minutes
• gentle waves that are low in energy

If they are situated on a gentle, sloping beach they have a long way to travel so the swash loses energy and therefore has a weak backwash.

These waves move sand and shingle up the beach. This increases the gradient of the beach due to material build up and this forms a Berm at its crest.

At 90 degrees+ the waves lose energy and therefore have further to travel.

These have:

• a wave height greater than 1m
• a wave length in proportion to 20m
• a wave period of 10-14 minutes.

They have a high energy and this results in the presence of storm waves, which usually occur on steeply sloping shingle beaches.

They have plunging waves that concentrate on a small area of a beach. The strong backwash results in narrow beach profiles.

They create storm beaches as stones are thrown above the high tide mark. Most material is carried down the beach by the backwash; this forms a Longshore Bar (breaking point).

The waves are stronger if the beach is steep and they approach at 90 degrees. As the material is carried back down the beach it becomes gentler in the lower section.