Down in a sinkhole

Before writing Wolf Mother (The Moonstruck Mother Series, Book 1), I’d never seen a sinkhole – let alone been in one – and if it hadn’t been for a research interview with a friend, that would most likely still be the case.

So, what is a sinkhole?

Basically, it’s a hole in the ground, that can either be created gradually, or suddenly. Three main types are:

  • Dissolution sinkholes
  • Cover subsidence sinkholes
  • Cover collapse sinkholes

They’re formed by erosion. Dissolution and cover subsidence sinkholes occur slowly, while cover collapse sinkholes occur suddenly. A common example of a cover collapse sinkhole is the cavern of an underground cave collapsing. So an area like the Limestone Coast in the South East of South Australia, is a great place to see these up close.

The three sinkholes I went in, for my research for Wolf Mother were the cover collapse kind, and they are:

  • Umpherston Sinkhole (Sunken Garden)(Mt Gambier, South Australia)
  • Depth: 20m
  • Width: 50m

Umpherston sinkhole is one of those places that photos just can’t do justice. It’s truly beautiful. The sinkhole was turned into an elaborate garden as you can see in the picture below. Behind the hanging plants, is a little hidden area, and at night, you can feed the possums that live there (they seem to be a fan of grapes and apple). The edge of the sinkhole is fascinating and reminded me of pancake-like layers of rock (nothing like the Punakaiki Pancake Rocks in New Zealand, but layers of rock just the same).

(This photo was taken from our first research trip to Mount Gambier in January 2019).

  • Cave Gardens (Mt Gambier, South Australia)
  • Depth: 30m

This sinkhole is located in the city centre of Mt Gambier. It’s deep, with a few viewing platforms along the way. It’s quite pretty, with plants, and colourful lights, lighting it up in the darkness. Unlike Umpherston sinkhole, which is not just deep, but also quite wide, the Cave Gardens sinkhole, like the entrance to Engelbrecht cave (see below), is narrower, and deeper.

(Cave Gardens viewing platform, this photo was also taken in January, 2019)

  • Engelbrecht Cave (Mt Gambier, South Australia)
  • Depth: 12m (according to google, though I have to say it felt deeper than that walking up and down the 164 steps!)

(The sinkhole entrance to Englebrecht cave)

Engelbrecht cave is located in the centre of the city. The caves consist of two separate caverns that you access via a sinkhole, and gives access (for cave divers anyway) to approximately 600m of underwater caves (and yes, I’m already thinking about ways to use this in subsequent books in the Moonstruck Mother series:-).

 So how does it feel to be down in a sinkhole?

Each of these sinkholes (as tourist attractions) were beautiful with exposed rock, and greenery. It’s cooler in temperature down in the hole, rather than above ground (as you’d expect). And although the ground beneath my feet was solid, and firm, I confess, I found myself wondering how stable ‘above ground’ was as we drove around afterward. Incidentally, shortly after we returned to Adelaide, a sinkhole opened up in my parents residential street, and although that particular sinkhole wasn’t as deep as these, it was pretty unsettling to see the broken asphalt and the hole in the centre of an intersection I’d driven over many times. (And it was a reminder that not all sinkholes are like the pretty ones above).

Anyway, if you’re wondering how a sinkhole fits into a book about a werewolf, you can find out here: