RADIO-tagged GPS pebbles have been placed on beaches to help scientists understand how sediment moves around the coast of west Dorset.

A total of 1,200 radio frequency tagged tracer pebbles have been deployed by Coastal Partners across six sites between West Bay and Freshwater Beach, Burton Bradstock.

The year-long study hopes to monitor the movement of the stones and sediment along this area to help with future beach management activities and schemes.

Founded in 2012, Coastal Partners is a partnership of four local authorities to design and manage the construction of new coastal defences, whilst researching critical issues such as flooding and erosion, and maintaining existing sea defences

A spokesman for the Coastal Partners said: “The specialist Radio Frequency Identification (RFID) kits can detect the tracer pebbles on the surface of the beach as well as just below the surface of the beach.

“The RFID scanners log each tag ID number associated with individual pebbles, as well as its precise location using GPS.”

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The tracers in the stones are not visible to the naked eye, which is done to prevent disturbance from beach visitors and are expected to spread out up to three km over five months.

On average 72% of the tracers will be detected every two weeks, with more than 95% being detected more than once.

The spokesperson continued: “The pebbles used for this tracer study were collected from West Bay in May 2021 and water jetted to create a hole into which the small RFID tags could be inserted.

“The hole is then sealed with resin and becomes undetectable to the naked eye.

“Using native material from the study site is important so that the tracer pebbles behave in a similar way once deployed.”

The tags use no power and are inserted into each tracer pebble broadcasting a unique ID number when detected using specialised GPS equipment.

This ensures that the position of each individual pebble can be tracked over the year-long period and further analysis can then be carried out.

Dorset and BCP Councils attracted £86,460 in local levy to undertake the study, alongside a £4,000 SCOPAC contribution, £2,500 from Dorset Council and £3,500 from the Environment Agency.

For more information on the study and the novel method created at Coastal Partners, see and