Rediscovering the lost ‘floating island’ of Mount Schank

In last month’s newsletter, Lachie took us on an interesting journey of discovery to learn about the mystery of the floating islands near Colac. A short time later, after reading Lachie’s article, my son Brendan (who shares an interest in history) contacted me to let me know he also recalled seeing old stories about a floating island in a small waterbody at Mt Schank, called Hood’s Pond, and proceeded to send me some links in several old newspaper articles. Now that I have also done a bit of extra digging myself, it looks like we have another floating island story to share!

Although it hasn’t been an exhaustive search, the earliest reference to the floating island at Mt Schank in the old newspapers that we’ve come across is from 1925:

Luckily, there is also solid photographic evidence from around this time, to help bring this description to life…

On reflection, it is probably no accident that there are few references in existence before this time, although this feature was very clearly present before then. This is because it was only with the growing availability – and then rapid rise in ownership – of motor vehicles from the 1920s onwards that vehicle based tourism became possible and some wealthier people had the ability to became more mobile in their leisure time.

Fortunately however, there is a reference to just how long the floating island had been known by locals, in another article a few years later.

The story below was provided to the children’s section of the Adelaide Chronicle (letters to “Aunt Dorothy”) in 1932, by 13 year old Eva Whitehead of OB Flat. She refers to the fact that the island was used by her great-grandfather (who was working on Mount Schank station as a shepherd) to protect his son (her grandfather) from a bushfire in the mid-1850s, by placing him on the floating island and hence surrounding him with water. This tells us that the island had long been a feature of Hood’s Pond – at least for the majority of time since European colonisation.

It turns out that a few years after Eva wrote her letter, the observation of the island growing into the bank eventually led the local council to take action, concerned about the loss of their drawcard. As they say in the article below, “while it was floating it was an asset, but when it was not it ceased to be an attraction“. So the overseer, a Mr. Kemp, was instructed to set the floating island free once more!

Once again, we are fortunate to have visual evidence of the floating island in 1935, showing it here up against the bank and possibly before it was ‘set free’.

But what was to become of Hood’s Pond and the floating island? If you are a local who lives nearby, you’ll know that there is no such feature today.

Well, as it turns out, in less than a decade Hood’s Pond would be gone forever and the floating island left grounded, as this rare feature and the small lake that sustained it – that was once estimated to be around 3 metres deep – became completely dry.

As you will read in the 1942 article below, one of the locals – Mr. Ashby – hypothesised at the time that the drainage of Eight Mile Creek Swamp, which is south of Mt Schank (or ‘downstream’ in groundwater gradient terms), had caused a drop in the local water table – noting that Hood’s Pond was a permanent waterbody, with groundwater expressed at the surface. Unlike much deeper features, like the Blue Lake or nearby Little Blue Lake, Hood’s Pond wasn’t deep enough to survive any significant decline in groundwater level.

To understand some of the wider trends going on with groundwater at the time, we have the benefit of the chart below, from a scientific paper published in 2014, that documented the decline in the water level since 1900, within the nearby Blue Lake at Mt Gambier. The Blue lake is a much deeper (70+ metre deep) feature that intercepts the water table and provides an indication of how it has behaved over the past century, in an area about 15km to the north (or ‘upstream’) of Mount Schank. While not a direct reflection of conditions in the groundwater level at Mt Schank itself, this could give us some clues…

As you can see above, a drier than average period (the solid line) until 1940, corresponded with a gradual decline (circles) in the water level in the Blue Lake, despite relatively modest water use (crosses) at that time. If we ignore the spike in water level around 1912 (in response to a very wet few years), there was an approximate 2 metre drop in water level between 1900 and 1940.

It also turns out that the drier climatic period between 1920 and 1940 corresponds with when Hood’s Pond vanished, and it seems plausible (to me at least!) that a falling water level likely contributed to the floating island becoming anchored by the early 1930s, several years before it dried up, as the water depth (and pond size) contracted.

Although Hood’s Pond was most likely an early casualty of a drying climatic phase 100 years ago, there is a lot more to consider when thinking about trends of loss in groundwater dependent wetlands today. A multitude of additional factors in addition to climate and artificial drainage of the region’s formerly extensive wetlands are relevant, such as changes in land use and increased extractive water use now impacting the presence, quality and persistence of groundwater expression wetlands across the Limestone Coast region and adjacent areas of western Victoria.

Despite this complexity, the question asked by Mr. Ashby in 1942 about the possible impacts of artificial drainage on the water balance was not only appropriate, but is still relevant today. While not all the modern threats to groundwater can be quickly or easily addressed, due to the nature of the long-term policy and planning decisions involved, at NGT we have spent the past 12 years demonstrating how reversing artificial drainage is one highly effective strategy for restoring wetlands and buffering local groundwater.

[Footnote – If anyone has another floating island story to share, please get in touch with me via email: ]