With summer holidays underway, many people will be heading to the coast to enjoy sand, surf and sun. Rover is fascinated by the different coastal areas he has encountered on his journeys, but sand dunes are something which he finds particularly of interest. Sand dunes shift in the wind and provide such a challenge to climb, but the thing which fascinates Rover most is that so many sand dunes are so much smaller than they once were, particularly around Botany Bay. He wondered, where is the sand going and what is the history of these dunes?
If you would like to see the amazing sand dunes around Botany Bay, they can be spied along Cape Solander Drive and Captain Cook Drive, on the way to the Kamay Botany Bay National Park. Sand dunes can also be seen within the national park itself. Some of the dunes which Rover finds particularly fascinating are those which are on the tops of cliffs, and you can see these by following Sir Joseph Banks Drive into another area of the National Park. Rover thinks it would be a great place to watch for whales, or even enjoy a picnic (though of course, it’s a little sandy), but make sure you watch the children – the area is unfenced!
Today, when you visit the area around Kurnell, you may well be amazed by the sand and dunes which sit atop the cliffs and run down to the sea. Once though the dunes were incredibly high, and as local residents and visitors recall they towered over the area and you had to crane your neck to see the tops. The enormous sand dune system at Kurnell is thought to be 1500 years old and it is believed that the dunes formed between 9000 and 6000 years ago when the seas and oceans began to settle at what are now their current levels. During this time, rivers ran to the sea under what is now the sand dune system but over time they deposited sands and sediment. It was actually this which joined Kurnell, which was then an island, to the mainland! The sand spit which joined Kurnell is called a tombolo. Eventually, the paths of the rivers were blocked entirely and they were forced to change their course, leaving behind the dunes.
The dunes around Kurnell and Botany Bay were not always exposed. In fact, despite the fact that the dunes were present when Captain Cook arrived, he makes no mention of them, because they were then covered with coastal vegetation. Early settlers in the area though, like Thomas Holt attempted to graze sheep and cattle on the dunes, but the land was unsuited to this (as were the animals!). The trees were removed and then the animals ate the grasses which stabilised the dunes. By the 1870s large areas of dune were exposed and by the 1920s people viewed the dunes as a desolate landscape – though it was popular with children! The desolate landscape was also popular with film makers who used the dunes to evoke desert and war. Movies ranging from Forty Thousand Horsemen to Mad Max have been filmed amongst the dunes. That doesn’t explain why the dunes have shrunk over the century though. The shrinking dunes are the result of a thriving sand mining industry which has been in place amongst the dunes since the 1930s. Today only a fraction of the dunes remain and since the Second World War it is estimated that over 70 million tonnes of sand has been removed. In the 1990s though the dunes were nominated for protection and today part of the sand dune system at Kurnell is actually formally recognised as an area of heritage values called the Cronulla Sand Dunes. Sand mining continues in other areas though.