Sidmouth cliff erosion worse than previously thought

Sidmouth’s crumbling cliffs at East Beach and Pennington Point are among areas that new research by Plymouth University on coastal change has predicted will see more erosion that first thought.

The research, which focuses on the eastern area of the district, is different from previous work on coastal erosion as it is for planning purposes only and maps a theoretical ‘worst case’ scenario of possible coastal erosion and includes an additional 10 metre buffer zone.

The study suggests that parts of the coastline at Seaton, areas either side of Branscombe and East of the River Sid at Sidmouth may see more erosion than previously predicted.

In contrast, the coastline between Seaton and Lyme Regis, west of Seaton to the edge of Branscombe and much of the coast west of Branscombe up to the cliffs east of Sidmouth may see less erosion.

Cliff East of Sidmouth
Cliff East of Sidmouth
(Image: East Devon District Council)

The research does not, however, take into account the protection that East Devon Beach Management Plan schemes currently in design will deliver.

East Devon District Council’s strategic planning committee on Tuesday recommended that Cabinet consider the wider implications of this study beyond the setting of planning policy at their earliest opportunity, but with a note of caution that further work may need to be carried out to provide a fully informed paper.

Cllr Geoff Jung, portfolio holder for Coast, Country and Environment, said: “This is clearly an important piece of work to inform future planning policy and it is very much distinct from work that we are doing on coastal protection measures.

“We’re making great progress in developing beach management plans and coastal protection works. These will be designed to slow the rate of erosion in Seaton and Sidmouth and hopefully prevent the worst case scenarios identified in this study from occurring.”

The study showed that areas where more erosion is predicted in the new maps compared to the current shoreline management plan in Seaton including some properties accessed off Beer Road and the Highcliffs Close area, two small areas either side of Branscombe mouth, and land in Sidmouth east of the River Sid including properties accessed off Cliff Road, Beatlands Road, Southway, Laskeys Lane and Alma Road.

But areas that are predicted to experience less erosion than the SMP maps include the section of coast from Seaton to Lyme Regis, much of the coast west of Highcliffe close in Seaton, through Beer to the east of Branscombe mouth, and the majority of the coast from Branscombe mouth to the cliffs east of Sidmouth.

The case study of East Devon, as part of that project, is evidence that could be used to inform the policies of the new local plan, and could help to deliver coastal protection schemes. The main purpose of planning for coastal change is to identify the places most likely to be affected and to develop policies to reduce future risks to people and property and to help communities at risk prepare and plan for future risks.

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Cllr Mike Howe said though that it was a hypothetical paper as it is untested, and doesn’t take into account the current planned defences in the pipeline.

He said: “It does need more work, but it does need to be done quickly, and I am nervous about using an incomplete and untested piece of work for planning purposes. We need to push this to Cabinet but heed the warning and not change the principle.”

Cllr Nick Hookway said that this was an issue we will all have to face and we shouldn’t look at it as a hypothetical, adding: “Maybe the algorithm is wrong but they’ll get it right later on.”

Cllr Olly Davey added: “Predictions are usually wrong, and the more specific they are, the more likely to be wrong, but sometimes you disregard that at your peril and we ignore this at our peril. This will be useful in highlighting some of the shortcomings in the current shoreline management plan around variations of rates of erosion in the cliffs.”

Sidmouth cliff collapse pictured from the Sidmouth Hotel & Spa
(Image: Andy Howell)

Cllr Eleanor Rylance added: “The best case scenario is it doesn’t get worse. We know global warming is happening and seas are rising, and the question is how much and the mitigation measures we take to limit CO2 emissions.

“I am not sure we should be proceeding with a best case scenario but a most likely scenario with the mapping, as with a best case, I am not sure we learn anything other than false reassurance.”

But with the study predicting worsening rates of erosion to the East of Sidmouth, Richard Eley, president of the Sidmouth Chamber of Commerce called for the Sidmouth Beach Management Plan process be paused.

He said: “We should suspend the Sidmouth BMP and hold an evidence based review. How can we carry on if nothing is happened if we know this report? It may do the town a favour and gives a refresh of the whole process and reset the plan.”

Option 1 - The preferred option that the beach management plan for Sidmouth has identified is to construct one or two new rock groynes along East Beach over a distance of up to 200m east of the River Sid and to modify the length of the seaward end of the River Sid training wall and East Pier rock groyne to improve sediment transport between Sidmouth Town Beach and East Beach. This would be supported by importing new shingle and moving shingle along the beach as required.
Option 1 – The preferred option that the beach management plan for Sidmouth has identified is to construct one or two new rock groynes along East Beach over a distance of up to 200m east of the River Sid and to modify the length of the seaward end of the River Sid training wall and East Pier rock groyne to improve sediment transport between Sidmouth Town Beach and East Beach. This would be supported by importing new shingle and moving shingle along the beach as required.

The beach management scheme for the town, consists of adding a new rock groyne on East Beach, importing new shingle onto Sidmouth Beach, and East Beach, and raising the existing splash wall along the rear of the promenade.

It aims to maintain the 1990’s Sidmouth Coastal Defence Scheme Standard of Service and reduce the rate of beach and cliff erosion to the east of the River Sid, the scheme is now fully funded and is estimated to cost £8.7m – subject to the Environment Agency approving the submission of the council’s Outline Business Case.

Devon Live