Constructive and Destructive Waves

Constructive Waves

It builds the beach up - it is constructing it. Small oceans with small fetch develop constructive waves. Constructive waves have low wave height and long wave length with low frequency, Constructive waves are associated with weak backwash and strong swash, which builds up wide flat beaches and so more associated with coasts of deposition. Constructive waves also tend to form sandy beaches.

Constructive Waves have

Has a gentle angle: there is a shallow gradient between the waves because there is a long gap between them and each wave is not very high.

Destructive Waves (angle)

Has a steep angle: the is a steeper gradient between the waves because there is a shorter gap between the waves and each wave is high.

Constructive Waves (swash)

Has a stronger swash than backwash (material is moved up the beach by the strong swash).

Destructive Waves (swash)

Has a weaker swash than backwash (beach is scoured and degraded as the strong backwash pulls sand and shingle back down the beach).

Constructive Waves (energy)

Has less energy.

Destructive Waves (energy)

Has lots of energy.

Destructive Waves

It removes material from the beach - it is destroying it. Large oceans with large fetch produce large waves, called destructive waves. These waves have large wave height and short wave length and are characterised by tall breakers that have high downward force and a strong backwash. This downward energy helps erode cliffs. In addition, due to a dominant backwash they erode the beach making for narrow steep beach profiles. Localised storms with high wind speed also form destructive waves as well as steep depth gradients around headlands. Destructive waves also tend to form pebbly beaches.

Destructive Waves (height)

Large in height.

Constructive Waves (height)

Small in height.