Nature’s impact on the beaches of sunny Sidmouth is taking its toll, which is why the council is working hard on a management scheme that will keep the beaches healthy and prevent further coastal erosion
Like many beaches along the South Coast of England, Sidmouth’s Main Beach and East Beach were formed many thousands of years ago, as glaciers melted at the end of the last Ice Age and sea levels rose rapidly. Cliffs that had previously been left stranded when sea level fell early on during the ice age became subject to erosion, releasing enormous quantities of gravel onto the shoreline and in the process forming the basis of many of the beaches we see today.
The gravel levels of the ice age, however, are a far cry from the appearance of these beaches today. Currently, there tends to be a very limited supply of new sediment to Sidmouth’s beaches, with cliff erosion typically providing fine silts and sand, which is rapidly drawn offshore.
As well as the importance of Sidmouth Beaches as an amenity, they form a key part of how the risk of coastal flooding and erosion is managed both now and in the future. A healthy beach protects the base of the seawall and promenade from undercutting, and dissipates wave entry before it can reach the seawall, thus reducing flooding or, on East Beach, preventing waves eroding the toe of the cliff.
Storms at the end of the 1980s stripped both Sidmouth Beach and East Beach of much of its shingle, causing damage to the promenade, and exposing the town to flooding from the sea with waves able to crash up against the exposed seawall. With little natural replacement of that shingle, in the 1990s structures were constructed to better hold a healthy beach in front of the town and large quantities of shingle were imported to reform the beach.
There were some teething problems with the scheme, with an additional groyne needing to be added at Bedford Steps. But, as can be seen today, overall this has been hugely successful, both in terms of protecting the town from flooding and storm damage, while creating a popular amenity for residents and visitors to enjoy.
However, with a continued limited supply of sediment onto East Beach, the resulting persistently low beach levels and some very wet weather, there has been a marked increase in erosion of the cliffs to the East of the town. This is not unique in the history of the Sidmouth and research by coastal scientists using historic mapping and other anecdotal evidence provided by residents has shown than similar periods of more rapid erosion have occurred in the past.
While this may not appear to be an immediate issue, as there is a significant distance before homes above East Cliff are themselves affected, there is a risk that as the shoreline recedes the River Sid’s defences become more exposed to coastal conditions and the main coastal defence outflanked. It is in response to such risk, that East Devon have been working with the Environment Agency and other statutory bodies such as Natural England, as well as the local community, to plan the management of the beaches. With three primary aims:
- To maintain the town’s protection against flooding provided by the 1990s coastal defences
- To reduce the rate of beach and cliff erosion on to the East of the town
- To carry out the above in an integrated, justifiable and sustainable way
The key outcome of this, was a recommendation that a beach management scheme be developed and implemented as soon as possible across Sidmouth Beach and East Beach. Based on the technical, environmental and economic assessment of all the potential options, the preferred option for doing this is to construct one, or possibly two rock groynes on East Beach in conjunction with shortening the River Sid training wall, import new shingle, and ongoing recycling of shingle.
The council is embarking on the first step of its journey towards delivering that scheme, which consists of completing the outline design, as well as an Environmental Impact Assessment (EIA) and Outline Business Case (OBC) for the scheme. These are required for Environment Agency approval, of both the scheme itself and for the approval of funding from DEFRA towards part of the cost.
Dave Turner, East Devon District Council’s Engineering Project Manager, who is the manager of the BMP project, explained how earlier this summer, residents may well have seen a boat out at sea, surveying the seabed and taking samples of sediment.
The work we are carrying out at the moment, is to take that information as well as other data about wind, wave, and coastal conditions to model the flood risk, and the response of the beaches to storm conditions. These computer models will then be used to refine the number and geometry of the new coastal structures, as well the frequency and volumes of import and recycling of shingle.
In parallel to this, we are working with the various statutory bodies to begin the process of understanding and mitigating against the various potential environmental impacts of the scheme and to ensure the scheme has the best chance of gaining planning and marine consents. This is to help avoid the issues with previous applications that have been made for coastal defence works on East Beach, which were recommended for refusal, including the environmental impacts on the Jurassic Coast World Heritage Site.
Another key issue during the next phase of the project is funding. Based on the work undertaken to date, the best case scenario for the scheme is that around £5.7 million of funding would be available from DEFRA, with an estimated £3.3 million of partnership funding required locally. It’s unlikely that East Devon would be able to commit to providing all of this funding alone, and the Environment Agency will be looking for the scheme to secure funding from a variety of sources including local residents and businesses before approving funding from DEFRA.
Completion of the EIA, Outline Design and OBC is planned for summer 2018. Should the council be successful in obtaining approval, as well as securing the funding from DEFRA and local partnerships, the earliest construction could feasibly start would be 2019.