What are the types of waves on a coast?

The two types of waves are destructive waves, and constructive waves. Destructive waves are well named, as they have a weak swash (the water that runs up the beach) and a strong backwash (the water the runs back towards the sea), so they take away much more sediment from the beach than the amount that they deposit. They can be characterised by steep waves that are close together. Constructive waves, on the other hand, are the opposite. They have a stronger swash than backwash, so they deposit more material on the beach than they take away. Constructive waves can be characterised by low waves which are further apart. Think of destructive waves as 'destroying' the beach by taking sediment away, and constructive waves as 'constructing' the beach, by depositing sediment onto the beach.