BMP will provide significant benefits - council’s coastal experts update Sidmouth & East Beach Management Plan steering group at third meeting
At the third meeting of East Devon District Council’s Sidmouth & East Beach Management Plan (BMP) steering group, on Tuesday 13 October 2015, the project received endorsement from Martin Davies, Flood & Coastal Risk Management Advisor at the Environment Agency (EA).
Martin Davies said:
The work done so far is very encouraging as it shows how valuable and important Sidmouth’s beaches are to help manage coastal flood and erosion risk in the town. Although there is more to do before funding can be approved, it is clear that it is beach management works, which will provide significant benefits”, he told the assembled council officers, coastal engineers and local community and environmental representatives.
Mr Davies also emphasised the importance of maintaining the BMP’s focus and said:
This project is about identifying the risks to the town caused by beach and cliff erosion, highlighted by the 2014 storms, and what beach management works can be done to reduce this. Once this is understood it will be important that organisations work together to manage the risks now and into the future.
The focus of the meeting was the presentation by coastal management experts CH2M of four baseline reports that are underpinning the development of the BMP, together with their long-list of potential coastal defence and beach management solutions. As the steering group was able to see, the BMP has made steady progress in the hands of CH2M, who have collected data from a wide variety of sources to produce highly detailed documents, encompassing: Environmental (final version), Defence Assessment (final version), Coastal Processes (latest draft) and Economics (latest draft).
The reports by CH2M pinpoint specific issues and current management practices, which will now be addressed by the appraisal of the long list of options, which will deliver the aims of the project. The reports show that the main coastal and river defences are sound, but the eroding beaches and cliffs will reduce their effectiveness.
Once the preferred options for beach management works have been agreed, East Devon District Council will apply in 2016 to the EA for central government funds to carry them out.
Coastal Processes Baseline
The purpose of this report was to provide an overview of coastal processes and an understanding of the evolution of the shoreline to the present day. CH2M’s assessment of cliff recession rates and changes to the shoreline and beach profile is based on fresh analysis of both new and historic aerial photography and mapping, together with anecdotal evidence. This research has helped identify key uncertainties, such as the rates of cliff erosion and to changes in beach levels over the years and decades.
CH2M have said that these uncertainties are primarily the result of insufficient good quality data. They have also highlighted the importance of understanding how to minimize/manage data error through expert judgement. So the report also provides recommendations on how to overcome these uncertainties in the future, such as a greater frequency of beach profile surveys, bathymetry (seabed surveys, further aerial photographic surveys of the cliffs and regular measurement of the cliff top position.
The Economics Baseline is the fourth report produced by CH2M and it is key in providing an understanding of previous economic appraisals and funding, as well as an up-to-date assessment of adverse economic consequences facing Sidmouth as a result of potential coastal flood and erosion damages. The assessment of these flood damages, which the council commissioned when it became clear that flooding of the town was not used to justify the 1995 coast protection scheme, shows that over the course of the next 100 years, a combination of property flood and erosion damage together with amenity damages could amount to almost £117 million. It is this figure that will be used to justify improvement works.
Coastal scientist, Alan Frampton, who is the CH2M project manager for the Sidmouth BMP, is confident that the BMP will identify solutions that can access a significant amount of grant aid funding to deliver them.
Alan Frampton said:
As part of the next stage of the project, we will use the Environment Agency’s Partnership Funding Calculator to help us identify the amount of beach management and coastal erosion funding from central government that could be achieved for each potential option before additional funding sources are required on top of that. However, the baseline reports have already shown that East Devon has an excellent economics case that will achieve a significant proportion of central government grant aid funding, which is distributed by the EA on behalf of Defra.
Long list of options (for beach management solutions)
Earlier in the year (on 14 July 2015), a workshop was held with CH2M, Tony Burch (East Devon’s assistant project manager) and Richard Edmonds of Jurassic Coast to discuss and agree a long-list of options for appraisal on a technical, economic and environmental basis.
A wide range of long list options (including the option of doing nothing) have now been identified for four areas:
- Jacob’s Ladder and Connaught Gardens (Chit Rocks). Options include: maintenance of Jacob’s Ladder wall and promenade, replacement with new structure, maintenance of rock revetment including repacking of rock at eastern end, extension of rock armour along toe of Jacob’s Ladder seawall, periodic removal of shingle from promenade area.
- Sidmouth Town (Chit Rocks to the River Sid). Options include: maintaining existing defence configuration, repair/replace training wall across the beach next to the River Sid, periodic beach recycling/recharging, raising height of the small wall at back of promenade, replace breakwaters, groynes and training wall with large scale rock or concrete stepped revetment, modifying existing rock groynes to form ‘T-head’ type groynes to improve sediment retention, remove the three rock groins and the training wall and replace with additional offshore breakwaters or submerged reefs, incorporating biological units to encourage sub-aquatic flora and fauna development.
- East Beach (River Sid eastwards to BMP boundary). Options include: a rock revetment at base of the cliff immediately east of River Sid, low level/’t-head’ type rock groynes, off-shore breakwaters or submerged reefs, clifftop drainage, cliff top slope regarding and pinning (soil nailing and netting).
- River Sid Western Wall (upstream of Alma Bridge). Options include: maintenance of existing western wall, replace wall with a coastal-standard vertical seawall.
Alma Bridge update
At the meeting, Nick Jennings, Devon County Council’s (DCC) principal engineer for bridges and structures, updated the steering group on Alma Bridge’s position. DCC has been looking at a number of new options for the bridge, including a new location, reusing an existing bridge (that DCC has in stock) and creating a diversion route over the River Sid should the temporary bridge become unsafe before the BMP is put into operation.
The Chairman of the Steering Group, Councillor Andrew Moulding, welcomed news from DCC that it will be undertaking survey work to help agree the cliff erosion rate, so that the lifespan of the bridge can be predicted, saying:
We are pleased that DCC are proposing a survey and are putting forward a range of other ideas for Alma Bridge. It needs to mesh together with the BMP, which DCC is doing.
Ham Sewage Pumping Station
In his talk about the Ham pumping station in Sidmouth, South West Water’s Waste Water Process Planning Manager, Chris Keyaha, emphasized the strategic position of the station, which serves around 9,000 properties within the town. He is keen to collaborate on the BMP because the pumping station is essential infrastructure and the risks to it as Pennington Point erodes and exposes it to wave attack needs to be assessed..
Commenting on the BMP’s progress and future actions that need to be taken, Councillor Andrew Moulding said:
One of the most important points to come out of today’s meeting is that we have a very good case for obtaining funding thanks to the work carried out by CH2M, whose detailed reports have been vital in identifying a case for us to put forward.
Everyone is in agreement that the historic data is not as accurate as we would have liked, but none the less it will enable us to move on and achieve a positive outcome.
CH2M are now working on an appraisal of the long list of options, which the council will consult the steering group on towards the end of this year. A short list of options will then be identified, appraised in more detail and consulted on early in 2016 through the steering group via a workshop. It is valuable for the project that we have input and support from the Steering Group members who bring local knowledge, experience and challenge to the process.
We will be identifying the most viable options and moving them forwards through the steering group consultation exercise.
It is anticipated that by late spring 2016 the production of the draft BMP, together with supporting documents will have been completed. This will be followed by a four week consultation on the draft BMP and then the finalisation of the Plan. Once this has been achieved, we can look forward to implementing the management scheme aimed at addressing coastal erosion and flood risk affecting Sidmouth and East Beach.