Two centuries of water-level records at Lake George, NSW

The year 2020 marked the 200th anniversary of European settlers first encountering the ‘noble expanse of water’ of Lake George in New South Wales. Since 1820, unofficial observations and official measurements of the lake’s water-level have been recorded almost continuously by various individuals, research teams, government departments and private companies. The lake’s recent hydrographic history has been characterised by periods of flood and drought, which correspond with the prevailing climate conditions of SE Australia. This is the longest water-level record of its sort in the Southern Hemisphere and hence of great scientific and historic value. Here, we have compiled all available historic water-level data for Lake George, referenced them to common datums and presented a methodology for continuing the record using satellite imagery in lieu of on-site measurements. KEY POINTS The 200-year water-level record of Lake George, NSW has been compiled and referenced to a common datum. This is the longest record of its type in the South Hemisphere, documenting the modern periods of flood and drought in southeastern Australia. Water levels for the period 1986–2019 when no on-site measurements were recorded have been estimated using satellite imagery and the lake’s bathymetry.