Ocean swimming is not a safe option when you’re holidaying on Fraser Island. The waves are rough and unpredictable, the sandbars are constantly moving and sharks have been known to cruise through the surf, but if you do fancy a swim there’s plenty of choice. There are more than 100 freshwater dune lakes on the island and their water is reputed to be the world’s cleanest.
Lake Mackenzie is a perched lake, shaped when a hard layer of decayed organic matter forms between dunes and water from runoff and rain begins to collect. Lake Mackenzie is the most popular of the lakes for water sports; its fine, white sand is almost pure silica and there is plenty of room for everyone.
Lake Birrabeen and Lake Boomanjin both have glistening, white, sandy beaches with water tea-stained by tannins from decomposing plants. They are also perched lakes and are not affected by surrounding groundwater. The water level rises and falls depending on the amount of evaporation and significant rains. At 200 hectares, Lake Boomanjin is the largest perched lake in the world.
Lake Wabby is classified as both a window lake and a barrage lake. A window lake forms when the level of the sand dune is below the water table, and a barrage lake is created when a sand dune blocks a water course. The constantly moving sand of the Hammerstone Sandblow is gradually overtaking Lake Wabby and eventually it will fill the lake completely.
All this fresh water has to go somewhere and the coastline is crisscrossed by a myriad of waterways. Some are tiny rivulets that flow out of the coastal bush across the sand to the ocean…
…while Eli Creek, on the east coast, is the largest. With a flow of 80 million litres a day more water pours out of Eli Creek into the ocean than out of Sydney Harbour.
So if it’s swimming and sailing you’re fond of, the inland lakes of Fraser Island are the perfect place to play.