Ridges are areas of the beach that are raised. The dips are water-filled troughs called runnels.

Ridge and runnels on Harlech beach, North Wales.

Find out more about landforms of coastal deposition.

Beach material is bounced along the seafloor.

Find out more about coastal transportation.

Rock fall, landslide, mudslide and slumping.

Find out more about mass movement.

A concordant coastline is where the same rock runs along the length of the coast. Concordant coastlines tend to have fewer bays and headlands.

Find out more about concordant coastlines.

Abrasion occurs as breaking waves, concentrated between the high and low watermarks, which contain sand and larger fragments wear away the base of a cliff or headland. It is commonly known as the sandpaper effect. This process is particularly common in high-energy storm conditions.

Find out more about coastal erosion.