The small city of Mount Gambier, located in the picturesque South Eastern region of South Australia boasts some of the state’s most amazing natural wonders. Of these, the most famous is the breathtaking Blue Lake; the only of its kind in the world.
The Geology of the Site
The land surrounding Mount Gambier is densely rich is limestone, due to the remnant of a shallow sea which lay over the region millions of years ago. This limestone, made up from fossils of fish and coral, forms a crust under the earth which extends for over two hundred kilometers and reaches a maximum depth at three hundred meters at Port MacDonnell, a small fishing town nearby. Over the years, this abundance of limestone has gradually been worn away by the ever flowing water table and has created an immense system of caves and underground cavern, providing a beautiful sight for divers.
The History of the Blue Lake
Mount Gambier’s Blue Lake is actually situated in a dormant volcanic crater and lies over fifty meters below ground level. Here, the crystal clear water found in the numerous underground caves is exposed, as it flows slowly through the layers of limestone under the city. The lake is made famous by the remarkable color changes it undergoes throughout the years. The summer months are the most spectacular, with the lake turning almost a fluorescent aquamarine. Following this, it starts to change back and maintains a steely grey color during the winter.
Why the Lake Changes Color
Many crazies theories abound as to why the Blue Lake is the color it is, the most common being that certain molecules in the water reflect the sunshine differently at certain times of the year. However, according to information provided by Mount Gambier Tourism Center the natural color of the water is blue. But why then, does the color change in the winter? The simplest explanation is the increase in rainfall causes a disturbance in the delicate balance between the layers which create such a blue color. Hence in winter, the position of the top layer of algae, largely responsible for the aquamarine color, becomes altered and the clarity of the water becomes decreased.
The Blue Lake: A Tourist Attraction
The Blue Lake is the single biggest tourist attraction in the city, thousands of people from all over the world travel to the region during the summer months to catch a glimpse of the azure color. There is a road which winds its way around the lake, with several look outs positioned along the way to allow you to stop and take in the view. However, if time is on your side there is also a footpath which surrounds the perimeter and is a favorite walk for locals and tourists alike. The circumference of the lake is just over three kilometers and provides a leisurely one hour walk, where the lake can be viewed from all perspectives. There is a variety of accommodation available for tourists meters from the lake and a quaint coffee shop which also offers a guided tour which takes participants on an exclusive route, right down the surface of the water.
For more information on the Blue Lake contact Mount Gambier Tourism or the Lady Nelson Tourism Information center at www.mountgambiertourism.com.au/.
Mount Gambier Tourism. (2011, March 20) About Mount Gambier – Geology. Retrieved from http://www.mountgambiertourism.com.au