Cliff remedies

SIR - In my letter to the Herald of February 15, I, in effect, argued that the overriding issue is not the steepness of the slope of the cliff but the rate at which it is being undercut by marine action.

Subsequently, at least two correspondents have added their support to a surfacewater drainage scheme as a first step.

I remain unconvinced by their arguments. What is the point of a “comparatively inexpensive contribution to slowing the escalating rate of erosion that is endangering the town” (Robert Crick, Opinion, 22 February) if the measure results only in a steeper slope to the cliff face, while the rate at which the cliff ‘moves’ landward due to sea action remains unaffected? He perceives a threat to the town but such a measure on its own would do nothing to reduce that risk. David Jenkinson (Opinion, March 1) states that “the main cause is the fundamental instability of the cliff because of its geology”. He plays down the role of the sea. Were the action of the sea (cliff undercutting and debris removal) to be omitted from the equation, then the cliff could be likened to an unsupported trench face.

Initially it would be unstable but under the effects of gravity and hydraulic action it would acquire an essentially stable long-term slope angle. If that was the situation prevailing east of the Sid then the cliffs would have already reached a relatively benign stable condition.

Clearly this is not the case. Unfortunately, it is the dynamic action of the sea that is the root cause of the cliff instability, not its geology.

I am fully aware that coastal erosion is a very complex issue and that any strategy to reduce land loss to the sea will include different approaches. Attempting to lower the water-table would probably be one of them, but not as a first step.

David McCluskey

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