Blue Lake

These wetlands in Kosciuszko National Park were listed under the Ramsar Convention in 1996.

Blue Lake Kosciuszko National Park Blue Lake is in Kosciuszko National Park and is one of only four cirque lakes on mainland Australia. A cirque lake is one in a valley that’s shaped like an amphitheatre and formed by glacial erosion.

Blue Lake has a unique dimictic thermal regime, which means it undergoes two seasonal mixing cycles a year.

Layers of cold and warm water reach the same temperature in spring and autumn and can mix throughout the lake. This helps regulate the temperature of water flowing from the lake.

The Ramsar site also includes Hedley Tarn, a smaller lake about 400 metres downstream in the outflow creek from Blue Lake.

Why these wetlands were listed as a Ramsar site

Countries that sign up to the Ramsar Convention can nominate sites to be listed as Wetlands of International Importance (Ramsar sites). The site must meet at least 1 of 9 internationally accepted criteria.

The wetlands around Blue Lake and Hedley Tarn were listed under the Ramsar Convention in 1996 because they meet the following criteria:

Criterion 1: Representative or unique wetlands

The site is a rare example of near-natural alpine wetlands, because it has been protected within Kosciuszko National Park for more than 50 years.

Blue Lake and Hedley Tarn are surrounded by alpine herb fields, heaths, fens and bogs.

Mountain pygmy-possum (Burramys parvus) during a survey of threatened species in Kosciuszko National ParkCriterion 2: Threatened species or ecological communities

The Blue Lake Ramsar site supports various threatened species, including:

The site also supports plants and animals important for maintaining the biological diversity of the South East Coast drainage division.

The site supports plant species limited to alpine areas, including:

  • snow buttercup
  • rock or branched caraway
  • snowpatch cushion-plant
  • Kosciuszko pineapple-grass.

How the site is managed

Management of this Ramsar site is guided by the following:

Threats to the Ramsar site

While Blue Lake and Hedley Tarn are considered to be in a near-natural condition, the main threats to this site’s ecological character include:

  • climate change
  • cloud seeding (a form of weather modification that increases rainfall)
  • recreation and tourism
  • bushfires
  • erosion and sedimentation.