I was out again yesterday, scrambling over the rocks below Boiling Pot Lookout in Noosa National Park. It is what biologists enjoying doing most, observing nature close up. All the better when you can sit-in your favourite marine pothole and see if the tide will eventually wash over you.
Waiting for sea level rise.
Before the moment of the highest tide, and before we had even made it around to the platform with the marine potholes, I found myself in the water, walking out to see where I had been just a few months earlier on the lowest tide for last year.
You might be inclined to think that we have sea level rise here in Noosa when you see these photographs, but it’s actually just a case of the time of year and the time of day. Because you see, the sea level is very affected by the sea tides.
The theory of the tides, and the maths used to calculate them accurately, was worked out by one man, Arthur Thomas Doodson, a profoundly deaf graduate of Liverpool university in the 1930s. So much good science was done back then when mathematicians, like Doodson, were encouraged to work from actual observations.
Yesterday, I specifically wanted to be at Tea Tree Bay for the highest tide of the year, scheduled for 9.33 am, Saturday 13th January 2024.
I always like to see how high the highest wave will crash against the platform with the wave cut notch – from a time of higher sea levels.
I am usually with my drone attempting to stay dry, but this year I left the drone behind and so I was at liberty to watched from a marine pothole.
The cliff face behind reaches up perhaps 30 metres to the famous Boiling Pot Lookout. There is a wave cut notch running right around the base of the cliff face – where the rock platform begins.
The cliff face has been formed by undercutting: from waves swirling beneath until they bring down great lumps of rock, to be removed by the wash. And so, the headland has receded landward, and the platform become wider. But it’s not happening anymore, because sea levels are not as high as they used to be.
Logically, sea levels must have once been much higher, because now, even on the highest tide for the year the waves don’t reach the bottom of the cliff face, the waves don’t reach to the notch. On highest tides long ago, the waves must have smashed against the cliff face.