The Blue Lake is a volcanic lake located in Mount Gambier, a small town on the Limestone Coast of South Australia. It is one of the famous natural landscapes in southern Australia. There are many legends about this Blue Lake as mysterious as Loch Ness.
Although it is called Blue Lake, the lake's color is not blue all year round. Every November, the lake's water mysteriously turns from gray to cobalt blue and then slowly fades again in summer. It was once believed that the blue lake changes color at different times of the year because the lake has no bottom.
The town of Mount Gambier was built on the site of an extinct volcano and is surrounded by four ancient volcanic lakes, two of which have dried up over the past 30 to 40 years as the water table has dropped, and the Blue Lake is one of the two remaining volcanic lakes.
Introduction of The Blue Lake
The Blue Lake is the most famous attraction on Mount Gambier. At the beginning of November every year, with the advent of summer, the gray-blue lake water mysteriously turns into a bright cobalt blue almost overnight, called the Blue Lake. Such color will continue until the end of February. After the end of March, it will turn back to that unique dark blue, which will last until November of the following year, and again and again.
The reason for this phenomenon is still unclear. Scientists believe that the surface water temperature of 20 degrees Celsius in summer causes calcium carbonate to separate from the water, forming tiny calcium carbonate crystallites, which form a bright blue when sunlight is scattered. In winter, the lake water is fully mixed and becomes dark gray-blue. In addition, the seasonal activity of plankton in the lake water may also affect the water color.
The Blue Lake Size
The Blue Lake is a large crater lake. The crater rim measures 1,200 by 824 meters (3,937 by 2,703 feet), but the lake itself measures 1,087 by 657 meters (3,566 by 2,156 feet) and covers a surface area of 70 hectares (170 acres). The lake's surface is 17 meters (56 feet) below the level of the main street of the nearby town. The Blue Lake has an average depth of 72 meters (236 feet), and the lake's deepest point was measured at 77 meters (253 feet) in 1967.
The water of Blue Lake mainly comes from rainwater and groundwater. Its water quality is clear and transparent, and it is the main source of drinking water for local people. There is a large pump station near the blue lake, mainly used to ensure that the lake's water level is always below the level of the town street and to purify the water.
The Blue Lake is a Monomictic Lake, which means that the lake waters are stratified by different temperatures throughout most of the year and do not mix with each layer. It wasn't until winter that the lake surface temperature dropped to about the same temperature as the bottom water, and the lake water began to mix.
There is a large revolving viewing platform by the lake, where you can enjoy the panoramic view of the Blue Lake and the town of Gambier. The 3.6-kilometer trail around Blue Lake leads directly to many attractions, the most famous of which is the underwater passage connecting Blue Lake and The Leg of Mutton Lake. Visitors can take a glass elevator directly to the shaft of the evacuated Dolomite shaft, observe the Blue Lake up close through the underwater tunnel, and understand the hydrological principles contained in Mount Gambier's water supply and aquifer system. Alternatively, stay in nearby towns to learn about local folklore and Aboriginal culture.