The Blue Lake at Mount Gambier in the state's south east is a volcanic crater that contains groundwater from local aquifer systems. The water seeps into the crater through porous limestone.
The total capacity of water in the lake has been calculated at 36,000 ML, making it the third largest water storage in South Australia. About 10% of the capacity is used each year by the regional City of Mount Gambier. Groundwater recharges the lake.
Water from the lake has been used for reticulated supply since the early 1880s.
The eruption that formed the volcanic crater is believed to have occurred nearly 5000 years ago.
Capacity: 36 gigalitres (one gigalitre is one billion litres), that will fill 18,000 Olympic swimming pools
Public access: Yes, via organised tours. There is access to adjoining Council land offering a walking trail and other interpretative facilities.
Opening times: Tours are available on request and are managed by Aquifer Tours. Council facilities are available 24 hours a day, seven days a week.
We currently don't monitor this reservoir's volume.