Emilia Guisado

Research by new graduate at the University of Ulster has settled a “riddle of the sands” at Portrush and rekindled concern about erosion at its famous West Strand.

Emilia Guisado, from Seville, Spain, who graduates today with the degree of Master of Research (MSc Res), has established that wave action is continuing to wash away the sand and the Strand has yet to find a natural level.

Her research shows that the sea wall has failed to halt rapid erosion, which is caused by unusual conditions not found on other parts of the north coast.

According to Professor Andrew Cooper, of the School of Environmental Sciences, the West Strand level has dropped 3ft. since the 1960s.  It is also only half its former width. Short of the expensive option of artificially pumping sand on to it, the Strand is literally on a downward slide.

“At the moment there is barely any beach left at high tide and it could disappear altogether to a stage where you would have waves breaking against the seawall.  There are plenty examples of that happening in other parts of the world,” said Professor Cooper, who is a specialist in coastal studies.

Investigating the effect of waves on sand movement at the strand, Emilia came up with surprising results which overturned an accepted view about the water’s ebb and flow.

“We simulated waves moving from deep water toward the shore using a numerical model,” she said. “The results showed that under nearly all wave conditions, there was a net seaward movement of sand. Only large waves from the northwest caused a net shoreward movement of sand. 

“This flies in the face of established theory which says that low energy waves promote sand build-up on beaches while storms cause erosion.”

Dr Derek Jackson and Professor Cooper, her academic supervisors, say the results graphically illustrate conditions at Portrush which are different from other north coast beaches.

Dr Jackson said: “We believe that these results show that the strand has not yet reached equilibrium with the surrounding environment and that is why it is behaving in this unexpected way.”

 “The West Strand beach was probably attached to Ramore Head and ran across to the opposite side of the bay several thousand years ago” said Dr Jackson “The peat that is sometimes exposed on it accumulated in a sheltered lagoon behind that original sandy beach. The beach has been moving across those old lagoon deposits ever since.”

The sea wall, rather than slowing erosion, has facilitated it, by effectively blocking the beach from finding its natural equilibrium, Professor Cooper explained.

“ The sea-wall at the beach has now prevented the beach from achieving equilibrium and has caused substantial narrowing and lowering of the beach since it was constructed in the 1960s,” he said.

“Photos of the pre-1960s show a badly eroded dune with layers of peat within it.  Putting the sea wall in to halt erosion has prevented the beach from ever reaching equilibrium and it has continued to become narrower and lower since the sea wall was built.”

Emilia is now is pursuing PhD. studies in Spain.


Winter Graduation News 2005

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