SIR – Mr Wolton’s letter in last week’s A&T sort of misses the point when he suggests work to restrict further erosion in order to “protect” beach huts at Hordle cliff.
He also suggests that loss of shingle is the cause of cliff falls at Barton.
Cliff falls and sediment transport have been natural phenomena along this stretch of coastline for millennia (since the last Ice Age at least) and are the result of soft geology, erosion at the cliff toe in winter storms, longshore drift and groundwater percolation.
The loss of shingle at Hordle cliff may be as a direct result of the rock armour and groynes installed at Barton, trapping sediment which would otherwise be deposited evenly along the coast.
Longshore drift is a powerful current which, when unrestricted, moves sediment eastwards. Groynes have slowed erosion during storms, but groundwater percolation continues to cause the rotational slips and cliff falls at Barton.
Where the rock armour stops near Becton Bunny there is an apparent increase in the erosion, however, without the armour the coastline would be more or less uniform from Christchurch Harbour eastwards, with erosion and deposition being in equilibrium.
The trouble is, as ever, interference in natural processes, which are best left alone.
If more hard, anti-erosion defences were to be installed, coastal engineers are always faced with ‘terminal groyne syndrome’.
Where do you put it and what impact will it have down-drift?
There have been umpteen studies looking at coastal processes in this area and systems put in place, many of which have failed judging by all the debris left within the cliff Site of Special Scientific Interest.
Why pour good money (our money) after bad?
Current thinking is to develop ways to work with natural processes of erosion and accretion, not against them.
Bob Lord, Barton