Gippsland Lakes and Paynesville have a unique character, defined by the presence of the Mitchell River Silt Jetties just off the mainland. These naturally formed silt banks stretch for over 8 km, making them the second-largest silt jetties in the world, and the longest in the southern hemisphere.

The Silt Jetties are of great interest to both scientists and visitors alike—an unusual natural feature rarely seen at this scale anywhere in the world. They are a form of delta known as a “digitate” or “finger delta” and are considered some of the finest examples of their kind globally. Since the destruction of the Silt Jetties on the Mississippi River in the Gulf of Mexico by Hurricane Katrina in 2005, the Mitchell River Silt Jetties are now claimed to be the longest in the world. It is especially remarkable that the Mitchell River—so small by comparison—should form such extensive and well-defined silt jetties at its mouth, where it empties into the lake system.

The Mitchell River carries sand and clay along its course, and during times of flood, large amounts of silt are picked up from the expansive catchment areas of the Mitchell River floodplains. This material is transported by the increased water flow until, nearing the river’s mouth, the flow slows down and can no longer carry the same volume of suspended material. The silt is then deposited and gradually settles. This process, occurring over hundreds of thousands of years, has led to the formation of the Silt Jetties. They are considered a growing feature of the landscape, constantly changing over time. Despite their impressive extent, the precise origin of the jetties remains a subject of scientific debate.

Scenic Flights 3, 4 and 5 include the Silt Jetties.