It is understood, from reliable sources directly involved with the work, that the principal cause of the major breach of the Dawlish sea wall was not so much the force of the sea crashing against the seaward face of the wall but the weight of water thrown over the wall on to the track which then needed to flow back into the sea and pushed the wall outwards from behind. Waves were recorded at six metres above the parapet and the weight of water falling on to the ballast quickly created voids, allowing large volumes of water to be trapped behind the wall, thus hydraulically bursting it outwards.
The damage occurred opposite the Dawlish Warren end of Sea Lawn Terrace and extended in front of a number of recently (and perhaps unwisely) built houses on the small area of land between railway and cliff face. Readers familiar with that stretch of wall will know that the pedestrian walkway which for much of its length is alongside and level with the railway, descends to a much lower level between Dawlish station and the Rockstone footbridge, just beyond Sea lawn Terrace. The reason for the lower-level footway on this section is that occupiers of what were originally smart family houses in the terrace, didn't want the public walking on the sea wall to be able to see straight into the houses and diminishing their privacy and a concession was therefore made to drop the footpath down almost to beach level, so low in fact that the path is impassable at normal high tides. Unfortunately, that means that the section of wall concerned does not have the usual nine-foot width of the footpath to buttress it on the seaward side and is therefore more vulnerable to damage.
It is likely that the long row of rock-filled shipping containers ingeniously and rapidly used to create a barrier immediately after the original breach occurred will be left in place when the line reopens. Behind them, huge amounts of concrete have been poured to fill the void under the railway. It is likely that this stretch of the wall will therefore look less elegant than usual for the coming summer. Decisions will ultimately be needed about how the whole wall is to be strengthened and only when that work is done will the temporary solution be tidied up. Interestingly, it was only because the engineering work in Whiteball tunnel finished ahead of schedule that the concrete spraying machinery developed specially to coat the inside of the tunnel, became available just in time to be moved to Dawlish where it was employed to spray concrete on to the base of the crumbling rock face exposed by the sea and which was threatening to undermine the houses mentioned above.
Derek Buttivant
The damage occurred opposite the Dawlish Warren end of Sea Lawn Terrace and extended in front of a number of recently (and perhaps unwisely) built houses on the small area of land between railway and cliff face. Readers familiar with that stretch of wall will know that the pedestrian walkway which for much of its length is alongside and level with the railway, descends to a much lower level between Dawlish station and the Rockstone footbridge, just beyond Sea lawn Terrace. The reason for the lower-level footway on this section is that occupiers of what were originally smart family houses in the terrace, didn't want the public walking on the sea wall to be able to see straight into the houses and diminishing their privacy and a concession was therefore made to drop the footpath down almost to beach level, so low in fact that the path is impassable at normal high tides. Unfortunately, that means that the section of wall concerned does not have the usual nine-foot width of the footpath to buttress it on the seaward side and is therefore more vulnerable to damage.
It is likely that the long row of rock-filled shipping containers ingeniously and rapidly used to create a barrier immediately after the original breach occurred will be left in place when the line reopens. Behind them, huge amounts of concrete have been poured to fill the void under the railway. It is likely that this stretch of the wall will therefore look less elegant than usual for the coming summer. Decisions will ultimately be needed about how the whole wall is to be strengthened and only when that work is done will the temporary solution be tidied up. Interestingly, it was only because the engineering work in Whiteball tunnel finished ahead of schedule that the concrete spraying machinery developed specially to coat the inside of the tunnel, became available just in time to be moved to Dawlish where it was employed to spray concrete on to the base of the crumbling rock face exposed by the sea and which was threatening to undermine the houses mentioned above.
Derek Buttivant