English Heritage has for many years been involved in coastal erosion issues at Dunwich. Although little remains of the once thriving town and Medieval port a few houses remain as well as scheduled ancient monuments, the Maison Dieu - a monastic hospital of the Holy Trinity and Greyfriars - a Franciscan Friary and St James Hospital - a former leper hospital. These monastic ruins are all that remains of the religious houses of the former town, with at least 8 churches and 3 chapels having been lost between 1086 and the present day.
We were therefore delighted when Time Team agreed to help investigate these sites and integrate them with the exciting maritime survey work of Dr David Sear who is investigating what survives of the town below the waves of the North Sea.
The results of the non-destructive geophysical surveys and targeted trial trenching provided exceptional data helping us to understand what remains of these once impressive Medieval houses and massive remains of the defensive town ditch which once surrounded the town. The Time Team investigations helped characterise the sites and will allow us to consider how best to respond to the challenge of coastal change.
Our wider national position is explained below:
Managing the coastal historic environment
The Government's basic principles of Flood and Coastal Erosion Risk Management (FCERM) are set out in Adapting to Coastal change: Developing a Policy Framework (Defra 2010). For much of the 20th century coastal management was focused on defence. More recently, the emphasis has shifted towards risk management, long-term sustainability and adaptation, especially in the light of current UK climate change projections. In other words, the assumption that dynamic coastal landscapes will be protected by sea defences need not necessarily apply - except for areas of high population density, or where significant infrastructure is located. In many rural areas the emphasis will be on adapting to change.
Responsibilities for managing flood and coastal erosion risk on the coast are shared between local authorities and the Environment Agency who collaborate in the production of high-level documents known as Shoreline Management Plans (SMPs).
The objectives of an SMP are to define, in general terms, the risks to people and the developed, historic and natural environment within the SMP area; to identify the preferred policies for managing these risks over the next 100 years and their consequences; to ensure that future land use and the development of the shoreline takes due account of the risks and the preferred SMP policies; to comply with international and national conservation legislation and biodiversity obligations; and to develop an action plan (Defra 2006).
Generally the SMP is broken down into policy units, and the most appropriate management approach is identified for each policy unit. The policy options are:
- Hold the existing line of defence - by maintaining or changing the standard of protection;
- Advance the existing defence line - by constructing new defences seaward of the original defences;
- Managed realignment - by allowing the shoreline to move backwards or forwards, with management to control or limit its movement; and
- No active intervention - where there is to be no national investment in coastal defence assets or operations. English Heritage (EH) has participated in the review of twenty SMPs around England in recent years but, of course, the historic environment is only one factor amongst many to be considered during option selection. Consequently protection of all heritage assets, especially in rural areas, is not assured and adaptation options must be considered instead - for example by increasing flood resilience of historic buildings, or by excavating and recording archaeological sites in advance of erosion.Heritage assets on the coast are thus vulnerable to the effects of natural coastal change, and to the impacts of coastal management schemes. Besides this, coasts are under pressure from the expansion of new or existing infrastructure and industry, especially at ports, and residential and recreational developments. Managing change in these situations depends upon a sound knowledge base. However, by the late 1990s it was clear that the coastal historic environment was under-investigated and records in the National Monuments Record (NMR) did not provide an adequate evidence base for responding to these challenges. Consequently, English Heritage initiated the national Rapid Coastal Zone Assessment Survey (RCZAS) programme. The RCZAS have two main phases:Phase 1 (Desk-Based Assessment) draws on data from aerial photographs, LiDAR, historic maps and charts, the local authority Historic Environment Records (HERs), the NMR, and other sources.Phase 2 (Field Assessment) comprises a rapid walk-over survey, designed to verify records from Phase 1, locate and characterise site types not visible from the air, and assess significance and vulnerability. In some cases additional work, especially scientific dating, has been necessary to characterise sites fully, which is being achieved via EH's National Heritage Protection Plan (NHPP).By late 2010 surveys had been completed, or were underway, in all parts of the country except the south-west peninsula where surveys will shortly begin as part of the NHPP. Additional coastal studies examining, for example, intertidal hulks and Grazing Marshes in Essex are underway or planned. The outputs consist of enhanced HER and NMR records, together with client reports for English Heritage which are available here. Results from the RCZAS have already been incorporated into books (e.g. Murphy 2009) and into the forthcoming EH Maritime and Marine Archaeological Research Framework. Aspects of the results are presented in talks, leaflets, and popular publications. Volunteer involvement is increasingly encouraged, with a view to establishing local groups who can continue to monitor sites, after the main phases of survey, and report significant new finds. In due course it is intended that a synthesis of the new results will be published to replace Fulford et al. (1997).The information gained will enable us to make a better-informed input to the FCERM process, and will help to ensure effective mitigation of the effects of coastal change on the historic environment through the 21st century. It will also provide a data-base for use in further research and in the development control process. Work has already begun as part of EH's Coastal Estate Risk Assessment, in which Environment Agency data on flood and erosion risk was overlain on survey data for EH's coastal properties within a GIS, to assess future risk and recommend actions (Research Department Report Series No. 68-2011, available here. As part of the NHPP further projects to assess the effects of flood and erosion risk on the full range of historic assets is proposed, taking the county of Yorkshire as a case study. Increasingly EH will be assessing risk and responding appropriately.
Department for Environment, Food and Rural Affairs (Defra). 'Shoreline Management Plan Guidance'. Volume 1: Aims and Requirements and Volume 2: Procedures, London: Defra, 2006
Department for Environment, Food and Rural Affairs (Defra). 'Adapting to coastal change: developing a policy framework', London, Defra, May 2010
Fulford, M., Champion, T. and Long, A. (1997), England's Coastal Heritage. English Heritage Archaeological Report 15. London: English Heritage and the RHCME
Murphy, P. 2009. The English Coast. A History and a Prospect. London: Continuum UK