My very first impression of Townsville’s landscape, thirty years ago, was of dead-flat land interrupted by peculiarly isolated hills and ranges, and it has only been reinforced over the years by views and events.
The views? Getting to know the topography from the top of Castle Hill, Mt Stuart or (most recently) Mt Marlow on the Town Common reveals a coastal landscape of mangrove flats rising (minimally) to the suburbs which wrap around the bases of the hills, with Ross River, Ross Creek and the Bohle River winding lazily through them.
Events? Floods and cyclonic storm surges, sadly. Floodwater pouring through most of your own suburb’s streets is an unforgettable demonstration of the tiny differences in land height. More recently, and more positively, getting out on my bike and feeling the little ups and downs in my leg muscles reminded me of the variations.
Taking the long view
I gradually learned that the topography beneath the surface of Cleveland Bay is similarly flat. The whole Bay is very shallow and in fact the strait between Magnetic Island and Pallarenda is so shallow that cattle were walked across it at low tide years ago.
If sea level were a few metres lower, as it was a few thousand years ago, Magnetic Island would be one more mountain range rising from flat open country, separated from Many Peaks by a valley. (I wonder if Ross River ran through it, or out towards Cape Cleveland?)
Contrariwise, if sea level were a few metres higher, as it may well be in a century or two, Many Peaks Range would be an island, with the Bohle to its West and a flooded Town Common to its South. It would be a smaller companion for Maggie. Their similarity is emphasised in the view below which, in fact, finally prompted this post after years of idle thoughts about the subject.
Eye-witness accounts
My previous post, which ended with Australia’s prehistory, probably motivated this one as well, since Aboriginal legends tell of the inundation of what is now our coastal shelf in the years after the last Ice Age ended 12,000 to 10,000 years ago. This account of them is worth reading in full. Here, though, is its beginning:
In the beginning, as far back as we remember, our home islands were not islands at all as they are today. They were part of a peninsula that jutted out from the mainland and we roamed freely throughout the land without having to get in a boat like we do today. Then Garnguur, the seagull woman, took her raft and dragged it back and forth across the neck of the peninsula letting the sea pour in and making our homes into islands.
So goes an Aboriginal story, paraphrased, about the origin of the Wellesley Islands in the southern Gulf of Carpentaria, a story with parallels along every part of the coast of Australia. Along the south coast, stories written down early in colonial times told when these areas were dry, a time when people hunted kangaroo and emu there, before the water rose and flooded them, never again to recede.
https://theconversation.com/in-a-first-discovery-of-its-kind-researchers-have-uncovered-an-ancient-aboriginal-archaeological-site-preserved-on-the-seabed-138108 says:
The paper is here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0233912#
There’s potential for Cape Cleveland to become an island, too – http://malcolmtattersall.com.au/wp/2021/03/mt-stuart-views/
An excellent presentation from the Dry Tropics Partnership For Healthy Waters (DTPHW) on Dry Tropics waterways and coastal waters with a focus on Ross River and Cleveland Bay. It includes visualisations of the area with both higher and lower sea levels. https://storymaps.arcgis.com/stories/40fb1343dd8f4a8f9edc3b51e2346943