Unravelling the Mystery of Lake George: the vanishing lake

After a morning of working in the garden it’s a relief to be out of the wind. Right now it’s blowing at 50 km/h and gusting to 59km/h. These spring wind gusts stir up a lot of fallen flowers and pollens, so all the while I was working outside digging, sweeping and planting I had an irritation in my nose.  It goes with the season.

The view from the Federal Highway, east, across Lake George.

All this strong dry wind heralds an El Nino event and a period of dry conditions which causes me think of drought and the iconic indicator of such events, Lake George.  It’s somewhat of a mystery lake. I can only recall seeing it full for a short period, for the most part it’s dry with a few muddy puddles after rain. This last La Nina period it’s started to fill again, but nowhere near the bank full stage I’ve seen in the past. It’s a bit of a mystery. The draining of Lake George is always a good sign that were entering an El Nino period of the southern oscillation (ENSO).

A Link with China

Once people suggested that Lake George had a subterranean link with China.  The popular myth asserted that it was conditions in China which determined its water level.  Of course this fanciful notion has long been dismissed.  A useful source on this is Gary Jones ‘Inside Water’ blog. In my experience, tour coach captains, often not renown for their accurate local knowledge, have added to the apparent mystery over the years embroidering layer upon layer of fanciful explanations for the lake’s appearance and disappearance.

Lake George Water Facts

Lake George is 25 kilometres north-east of Canberra. It has a catchment of 984 square kilometres, 16% of this occupied by the lake. It’s a small system just 25 kilometres long, 10 kilometres wide, very shallow and, for a lake in eastern Australia, very salty. Unless there’s significant rain in the catchment it seldom has much water. Just 10 minor tributaries feed the lake which sits at 1350 metres above sea level.

While the mean annual rainfall in the area is 750mm it does have appreciable amounts of water in La Nina periods, if rain is falling in the catchment.

The ten minor tributaries that feed the lake have little surface outflow. The only data I could find for these was for the 25 Km long Turallo Ck which at the time of writing had a depth of 0.62 metres and was discharging at a rate of 32.9 ML/day around 80% of its bank full flow. The NSW department of Primary Industries Office of Water, provides some real time data on Turallo Creek.

The Lake’s Murray Cod Industry

In the 19^th century there was actually a fishing industry on the lake.  Well, perhaps industry is somewhat of a misnomer. Murray Cod were translocated from the Molonglo River to the Lake George area in 1848.  This stimulated a fishing industry, but this must have been in a La Nina period. The population that developed in Lake George was used as a source to stock the Wollondilly and Cox’s Rivers and Mulwarree Ponds near Goulburn in the Nepean Catchment .  For the reference on this see Species Summaries: An Analysis and Summary of Historical Information on Native Fish.

A new capital for a new nation

Reporting in the Canberra Times on March 12 this year, Ian Warden made an inspired contribution to the lake George saga.  He reminds us that “Mystical Lake George, once upon a time one of Canberra’s rivals as the chosen spot for the federal capital city”.  Reading this piece reminded me that I’ve actually seen the plans for the proposed national capital site at Bungendore.

Plan shewing proposed Federal Capital site in the locality of Lake George. http://nla.gov.au/nla.map-vn437205

An expedition to Lake George

On Tuesday I head off to the lake. My son and I will attempt to paddle our kayaks on what water there is. This could be a once in a lifetime opportunity, something he can tell his grandchildren about. Hopefully I’ll be able to join the conversation as well.

Whether or not we succeed is problematic.  The lake seems fullest at its eastern edge, but this area is surrounded by private land holdings and I don’t know whether we’ll gain entry.  Still there’s a good chance we will, since this shoreline, rather the low line of hills above it is the site of a major wind farm.

Wind Farms

I took photograph at the top of this page from a bus moving at around 100km/h back in late July. I appreciate the hues but I’m also rather taken by the wind farm in the background.  Wind farms appeal to me.  Perhaps it’s just from a childhood fascination with those Southern Cross wind pumps that dotted Australia’s arid landscape.  There were always displays of at agricultural shows in Sydney, the Royal Easter Show to be precise.

Wind farms are a controversial topic, but I really enjoy them.  There’s a small wind generator not far from where I live.  More about this in my next post.