Are we running out of sand?
Humans see sand as an infinite resource. We are astounded to discover there are more stars in the universe than grains of sand on our beaches.
Yet in some areas, sand is in short supply and scientists have discovered the way we keep track of this resource has given us misleading information.
In many instances, we have simply been measuring sand the wrong way.
“Not all sand is the same,” said Associate Professor Ana Vila-Concejo from the University of Sydney.
“Yet the models for assessing sand and how it moves mostly rely on one type. This means we have an inaccurate picture of what is happening, especially in coastal areas that are vulnerable to climate change.”
Dr Amin Riazi from Eastern Mediterranean University worked with Assoc. Prof. Vila-Concejo to develop new engineering models that account for the different shapes of sand grains.
Standard models assume sand grains are spherical, which is fine for common sands made up of ground-down silica and quartz rocks.
However, carbonate sands derived from shells, corals and the skeletons of marine animals tend to be elliptical, less dense and have more holes and edges.
The new research has taken this into account with astounding results, finding that existing models underestimate the surface area of carbonate sands by 35 per cent.
The research has shown that standard engineering models also overestimate transport of carbonate sands on the seafloor by more than 20 per cent and underestimate suspended transport of this sand by at least 10 per cent.
“This means we are not accounting for sand correctly,” she said. “While this has impact on construction and manufacturing, it could also have a big effect on the management of coastal areas impacted by climate change.”
Sand is used throughout industry. From the glass in your mobile phone to base for roads, sand is used across our economy. In fact, sand and gravel are the most extracted materials on the planet, exceeding that of fossil fuels.
Nature last year reported that illegal sand mining is happening in about 70 countries and hundreds of people have been killed in battles over sand in the past decade.
Assoc. Prof. Vila-Concejo said: “While sand wars are not happening in Australia, we do have areas with chronic coastal erosion and sand loss such as at Jimmys Beach in Port Stephens.”
Did you know that sand was a finite resource?
Yes we are running out of sand, we live in a concrete jungle and all the billionaires want their own island and need to buy sand from other countries to build. Lots of sand is sold on the black market.
The famous white-sand beaches of Hawaii, for example, actually come from the poop of parrotfish, so if the parrot fish becomes extinct, there will be no sand in Hawaii and they will have to buy their sand.
:) Quite important where I live on the Gold Coast. The value of sand ...
Q: What makes Queensland beaches so beautiful?
A: NSW dirt — and longshore drift
This intricate natural process was disrupted in the 1960s when training walls were extended approximately 380 metres to make it easier to get boats in and out of the Tweed River, just metres from the Queensland-NSW border, thereby cutting off the sand supply to Queensland's southern beaches. So, about 40 years after the training walls were built, "sand bypassing" started in 2001. The pumps do not 'suck' sand from the ocean bed, or out of the Tweed River, but collect sand that is naturally transported to the jetty through the process of longshore drift.
https://www.abc.net.au/news/2020-06-13/weather-longshore-drift-queensland-nsw-beaches/12347828
I guess everything is finite -- but we did have sand taken from the east coast of Aussie to Hawaii and sand is still being mined at Stockton areas