A new theory about waves in the surfzone was developed using a computer model. The theory shows that interactions between different types of waves help to balance the energy in the waves. In the shallow water near the shore, the energy of certain waves increases, while in the deeper water, the energy decreases. The energy loss happens when the waves break or interact with each other. The study found that on a gentle slope, most of the energy loss is due to interactions between specific types of waves.