coasts-waves

constructive waves:

• 
• Form in low energy environments.
• Have a low wave frequency (6-9 per minute)
• Have a strong swash to bring material onto the beach and a weak backwash so that it isn't removed. This weak backwash is created by a long flat beach that absorbs the energy. The type of beach it creates.
• Have a very low and long appearance.

destructive waves:

• 
• Form in High energy environments.
• Have a high wave frequency (10-15 per minute).
• Have a weak swash that doesn't bring material to the shore and a strong backwash that removes any sediment brought in during a relatively weak period and then attacks the rock underneath scouring out a hole. because the wave it forms has a steeper gradient the wave builds up height as it nears the beach and then plunges with more force.
• Have a narrow and tall appearance.