Scientists released 4,800 tidal drift cards off the coast of Kent in the autumn of 1967 as part of a study of the surface currents of the North Sea. Most of the cards were returned to the Hydraulics Research Station (which became HR Wallingford in 1992) within a few months of their release, but one of the cards was found in February by Vincent and Jasmijn who were beachcombing near their home on the island. The pair regularly trawl the beach for treasure, using wood to make lamps, and collecting plastic to make new products.
The majority of the cards were found 50 years ago along the coast of Kent and the southern coastline of the Netherlands. The average distance the cards travelled was between five and 10 miles a day. A few reached as far north as Jutland in Denmark and as far south as Cap Gris Nez, France. Eight years ago, some cards were discovered in Denmark and Germany after storms.
In the time since that study, the organisation’s methods for monitoring surface currents have changed dramatically. Scientists now conduct surface current studies using state-of-the-art computer modelling.
Fifty-three years ago, the Hydraulics Research Station offered a reward of 2/6 to people who returned the tidal drift cards. HR Wallingford sent the 2020 equivalent – €5 – to the Dutch beachcombers as thanks for getting in touch about the card.