How can waves form inside a lagoon?

Small waves can form inside a lagoon primarily through the action of wind. When wind blows across the maximum dimension of a lagoon, it generates these waves, which can reach heights of up to 1.25 metres (about 4 feet) and lengths of 1.5 to 9 metres (about 5 to 30 feet), as observed in the Gippsland Lakes system.1

Additionally, rhythmic oscillations known as seiches can occur within these enclosed or partially enclosed water bodies. These are often created when strong winds blow water into the lagoon, raising its level and subsequently triggering an outflowing current when the wind subsides. While lagoons are generally characterized by quiet, sheltered water protected from direct open-sea wave action by barriers such as sandbars or coral reefs, these internal mechanisms allow for the development of localized wave activity.12