What happens with the water in Lake George?
Does it really drain to NZ by underground aquifers.
This is a question that has been asked by many. People talk about the old days when it was full, and the old days when it was empty. How it had lots of water and seemingly overnight the water vanished. For 20 years the lake has been dry and now it is nearly at 1990 levels where it was lapping at the edge of the highway. Of course there has been major work done with the duplication so this may impact how close to the highway the water gets now. But this virtual will hopefully be a record of the Lake over time.
To claim this virtual please take a photo of yourself at the lookout with your geocaching name or something that shows you are a geocacher with the Lake in the background and upload it to your log.
Lake George (or Weereewa in the Ngunnawal language) is an endorheic lake (as it has no outflow to rivers and oceans) in south-eastern New South Wales. The lake is believed to be more than a million years old. Originally, small streams drained its catchment into the Yass River, but then the Lake George Escarpment rose due to major crust movement along a strong fault line, blocking this drainage and forming the lake. Lake George has in previous Ice Ages been much larger and deeper.
The thickness of sediment beneath the lake exceeds 250 metres (820 ft), according to a Bureau of Mineral Resources Canberra drilling programme in the 1982/83 summer. The oldest sediments, which lie some distance above the bedrock, were dated at 4–5 million years using spore and pollen analysis and magnetic-reversal stratigraphy.
At 25 km (16 mi) long and 10 km (6.2 mi) wide, Lake George is long, largely flat and extremely shallow, with a very small catchment. Resultant evaporation rates as well as a tendency for strong winds to blow the water back on itself explain the mysterious filling and drying episodes on both short term (hours) and long term (years) time scales that have been observed.
The lake's depth when full can range from 1.5–4.5 metres; however in many areas it is only around 0.8–1.0 metre deep. Its deepest point has been measured as 7.5 metres. When full, the lake holds about 500,000,000 cubic metres of water. Between the late 1980s and mid-1990s, the lake lapped the Federal Highway on its western edge.
Lake George is one of the most studied lakes in Australia. The palaeontologist Patrick De Deckker has commented that "it is actually a depression that turns into a lake when it fills. There’s always water below the lake floor, and amazingly, it is saline, but if you have more rainfall, the lake fills up".
The foreshore of what is now known as Lake George mainly lies within the traditional lands of the Gundungarra, but its south-western foreshore is at the extreme east of the traditional lands of the Ngunnawal people. These two peoples spoke a very similar, if not identical, language. The traditional lands of the Ngarigo people probably also extend to the lake's southern shoreline, in the area now known as Bungendore. The lake lies not far from the traditional lands of the Walbanga people (a group of the Yuin from the upper Shoalhaven catchment), to the east.
The unusual fluctuations in the water level have given rise to fanciful urban myths that the lake is somehow connected to lakes in Peru or South Africa, although NSW government ecologist Justin Nancarrow theorises that the lake may indeed be connected to the nearby Yass River by subterranean aquifers which pass under the surrounding escarpment, and that this connection may explain the salinity of the river (info from Wikpedia)
Virtual Rewards 3.0 - 2022-2023
This Virtual Cache is part of a limited release of Virtuals created between March 1, 2022 and March 1, 2023. Only 4,000 cache owners were given the opportunity to hide a Virtual Cache. Learn more about Virtual Rewards 3.0 on the Geocaching Blog.