Beach Management Plan: raising the height of the splash wall

“… is a proposal that will continue to be considered very carefully as the outline design progresses.”

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The Science:

The question of putting up a splash barrier on the Esplanade has been with us for well over a year, with the last report back in February looking at ‘the science’:

Beach Management Plan: splash barrier and sea level rises – Vision Group for Sidmouth

… but what will be the final height?

Since then, further testing has been carried out:

Sidmouth seafront glass splash test survives Storm Ciara | Sidmouth Herald (12 Feb)

Sidmouth Beach Management Plan: Glass panel test wall survives two storms | Sidmouth Herald (19 Feb)

Sidmouth’s glass test ‘splash’ panel damaged | Sidmouth Herald (11 March)

At the end of the summer, it was announced that there would be further consultations:

A temporary glass splash defence test panel, that was installed on the Sidmouth seafront, has passed almost undamaged.

The glass panel was installed on The Esplanade between the York Street and Fore Street junctions, to test whether glass could be used to reinforce Sidmouth’s sea defences on the line of the existing short wall. 

The next phase of the Beach Management Plan is to hold a public exhibition – location and format to be confirmed given Covid-19 restrictions – where people can make comments on the various types of splash defence available, and, given funding constraints, give an indication of what their preference is for what method in which location.

Glass splash wall on Sidmouth seafront would need CCTV and vandalism deterrents | Sidmouth Herald (17 Aug)

To reiterate the science:

Sea level rise relative to the land is the combination of absolute sea level rise and vertical land movements. By 2100 relative sea level could have risen by as much as 80 cm around some parts of the UK coast (4).

Coastal flood risk United Kingdom | climatechangepost.com

But looking at the mapping for the UK, Sidmouth will not be nearly as badly affected as other coastal areas:

FireTree Flood app

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An incremental approach:

So, the one metre height of the proposed splash wall being proposed will not be necessary immediately – or perhaps at all. This has given rise to a demand that the wall be added to over time – that there be an ‘incremental approach’:

That we are not necessarily obliged to erect sea defences today according to predictions for levels in 100 years – and that this could be done in stages over time.

The Environment Agency acknowledge that in sensitive and accessible locations, an incremental approach is justified – and Sidmouth’s Esplanades is in a Conservation Area, with numerous listed buildings and several hotels.

Indeed, at the August 2019 meeting of the Steering Group, the minutes state that the idea of incrementally increasing the splash wall was not dismissed and was an option that ‘could be considered’.

Beach Management Plan meeting: August press release – Vision Group for Sidmouth

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0.5m or 1.2m?

Looking at the BMP press releases, in June 2018, the height was to be half that now proposed:

The meeting followed on from a well-attended public exhibition on 19 April 2018 at which Royal HaskoningDHV presented the background to the scheme and the proposals to recharge both Sidmouth Beach and East Beach, add a groyne onto East Beach, and increase the height of the existing splash wall… 

Royal HaskoningDHV’s thorough tests and methodical approach has resulted in a proposal to recharge the beach with a 10m flat section at the top, and a suggested increase in the height of the splash wall of up to 0.5m from its existing level, with sections of lower height where the beach is less exposed.

East Devon and Royal HaskoningDHV emphasised that during the design development, they have been conscious of the potential impacts that a higher splash wall might have on the town. Raising the height of the splash wall is a proposal that will continue to be considered very carefully as the outline design progresses.

Press releases about the Sidmouth and East Beach Management Plan – 4th June 2018 – ‘Outline business case for Sidmouth and East Beach Management Scheme makes steady progress’ – East Devon

And this was widely reported in the press:

Sidmouth beach splash wall raised to stop erosion – but offshore breakwaters too expensive – Devon Live

At the last meeting of the BMP steering group in August last year, it was recorded that there is ‘concern’:

Design details of the raised splash wall (which a number of representatives expressed concern over the height) will be the subject of further work involving the steering group and future consultations. It is currently anticipated that this wall will need to be at one metre above the promenade to contain wave overtopping.

Press releases about the Sidmouth and East Beach Management Plan – 30th August 2019 – ‘Sidmouth Beach Management Scheme Steering Group meeting update (August 2019)’ – East Devon

In January this year, a much higher level was referred to :

A splash defence is required to protect Sidmouth from flooding from storm events, which pushes large waves over the sea wall. The existing splash wall does a good job stopping sea water flooding the town, but with a predicted sea level rise due to climate change, and more extreme weather, it will no longer stop flood water entering the town, so it does need to be improved. In the South West, the Government is requiring coastal projects to have a minimum allowance for 1.2m of sea-level rise in the future due to global warming and the district is already experiencing more frequent storm events, therefore the town’s defences need to be upgraded.

Press releases about the Sidmouth and East Beach Management Plan – 16th January 2020 – ‘Temporary glass flood defence panel to be tested on Sidmouth esplanade as part of Sidmouth and East Beach Management Plan’ – East Devon

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Designs and plans:

Finally, there are the visual representations from the public consultation back in 2016:

Sidmouth Through the Ages

Information Posters – The Scheme At A Glance – East Devon

And there is the study produced  by the VGS in 2018:

As can be seen, all sight of the sea is lost from ground level all along the Esplanade. When the flood gates are closed the effect will be even stronger.

BMP May 2018 – Vision Group for Sidmouth

photo: Experimental protection glass, Sidmouth… © David Smith :: Geograph Britain and Ireland

   
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