How many grains of sand are there on a beach?

A team of leading international scientists has begun one of the most comprehensive studies on a sandy beach in the UK and will address the question ‘how many grains of sand move up and down the beach under different waves’.

Researchers from Plymouth University will be working with counterparts in America and Australia to investigate how sand is moved up and down the beach by breaking waves.

The team will deploy over 100 state-of-the-art instruments to record water levels, flow speeds, rates of sand movement and beach change at Perranporth in Cornwall - and from the data will be able to calculate the total number of grains moved up and down the beach.

Professor Gerd Masselink, of Plymouth University’s School of Marine Sciences and Engineering, is the coordinator of the research effort. He said: “This very comprehensive field experiment has been five years in the making and will provide new fundamental knowledge on how sand moves on beaches. This information will help develop computer models of sediment transport and coastal erosion and will improve predictions of how beaches respond to climate change.”

The instruments will be deployed from a 40 metre-long scaffold structure inserted at the high tide level and data will be collected using a bank of laptop computers housed in a mobile field laboratory installed at the top of the beach.

The University of Delaware will be recording the movement of the seabed itself as the wave passes over. Dr Jack Puleo, from the university, said: “Conditions on Perranporth beach are ideal for this research: the large tidal range will allow the installation of the instruments with relative ease and the large waves will ensure significant sand movement at high tide when measurements will be made.”

The University of New South Wales will use their instruments to accurately measure the shape of the beach after each wave has run up and down, recording the net difference. Representative Dr Ian Turner said: “For every wave that runs up the beach, the instruments used in this field experiment will give information on the transport of sand in the water column, the movement of the sea bed itself and the net change in the beach shape. This is the first time that such comprehensive measurements will be recorded on a beach.”

Professor Paul Russell of Plymouth University added: “By continuously measuring how many sand grains move up and down the beach we know the net movement and so the amount of erosion (or accretion) caused by different waves. This allows us to characterise which waves cause most coastal erosion."

Provided by University of Plymouth