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Wetland and Waterlogged Heritage Survey NHPP Activity 3A5

Research carried out 2011-2015 about identifying wetland and waterlogged archaeological sites to help prevent their loss. These vulnerable sites give us important windows into the past because of the well-preserved remains found in them. The work was part of the National Heritage Protection Plan

Photograph showing archaeologists working at a waterlogged site, Woodstreet, Nantwich, in the centre is a line of medieval wooden barrels.
Medieval wooden barrels preserved in waterlogged deposits at 2, Wood Street, Nantwich. © Earthworks Archaeological Services 2003

Scope of the activity

Wetlands provide excellent preservation conditions for organic archaeological remains. They can also preserve evidence of environmental change, helping us to understand long-term ecological and climatic trends that influenced people’s lives. Wetlands include surface water features (e.g. ponds and rivers) and saturated ground (e.g. peatlands and alluviated floodplains). They can be fed by freshwater or brackish water. Waterlogged archaeological deposits are common to all these types of wetland.

However, waterlogged deposits can also lie hidden beneath agricultural or urban land where there are no clues to their presence at the ground surface. This means that such deposits can be challenging to identify, so we need to continue developing methods to help recognise such places and reduce the risk of accidental damage or unexpected discoveries.    

Waterlogging has given us iconic prehistoric sites such as Lindow Man bog body, the Sweet Track causeway, the timber structures of Flag Fen, the Dover Boat, Seahenge, the Mesolithic settlement at Star Carr and the log boats at Must Farm. It has also preserved extensive and exceptional historic remains in urban centres such as York, City of London and Carlisle. However, such deposits are vulnerable to subtle changes in burial conditions, in addition to the usual threats from development and changes in land-use.

In 2000, Historic England commissioned the University of Exeter to research Monuments at Risk in England's Wetlands. This study suggested that over the past 50 years, we have lost half of England’s original lowland peatlands and that as a result, around 3000 wetland archaeological sites have been lost and 10,000 damaged.

Photograph showing archaeologists excavating waterlogged Iron Age Boats
Waterlogged Iron Age log boats preserved in alluvium at Must Farm, Whittlesey Pits (Hanson Building Products Ltd), near Peterborough, Cambridgeshire. © Paul Stamper,Historic England

Expected protection results

Knowing where such sites are, and explaining their value as evidence about the past to a wide audience, are the essential first steps to improving their protection. Projects in this Activity have provided better understanding of the location and significance of particular categories of wetland and waterlogged asset and so support decision-makers working within the planning system. The Activity delivered information to help those working as heritage advocates with the natural environment sector.

Image showing a distribution map of waterlogged sites in Nantwich , Chesire
Distribution map of waterlogged deposits in central Nantwich. © SLR

The Projects

Exceptional wetland and waterlogged heritage

Building on work of the Heritage at Risk in England’s Wetlands project, by the University of Exeter (2004), this project produced an inventory of the nation’s most significant wetland and waterlogged heritage sites and landscapes to promote understanding of where and what they are, accompanied by statements of why we value them.

Some places have recently been Scheduled, we are assessing others, but we will not be able to consider all of them for designation. This is because despite their importance to the archaeological record, many do not fit the criteria required for scheduling under the current system. Regardless of status, we want to highlight those wetland and waterlogged sites considered to be of exceptional evidential value with a view to future projects reviewing the site-specific risks to their continued preservation and reviewing management options to win better protection where possible. See the inventory first stage report.

Distribution and significance of urban waterlogged deposits

Waterlogged urban stratigraphy can be extensive and of exceptional significance but standard survey techniques are insufficient to model and map such zones. This group of small projects will synthesise existing information to refine understanding of the distribution, condition and potential of waterlogged deposits in a range of urban centres.

We developed tools to aid their recognition and to help new archaeological work. Products included desk-based assessments collating existing information; the construction of deposit models; Historic Environment Record enhancement; and the production of GIS resources to flag areas with known or modelled high potential for waterlogged deposits. Project reports are available for Bristol, Berwick-upon-Tweed, CarlisleBoston, Droitwich and Nantwich. The Nantwich project was the precursor of the wider series. The Nantwich study also includes monitoring of burial conditions beneath the town so that changes in these, and the condition of archaeological remains, can be assessed using data from commercial archaeological excavations.

Small wetlands

This programme comprises two projects to assess the significance and heritage value of small wetlands. We already know that they are just as important for archaeological evidence and evidence of past environments as extensive wetland landscapes such as Humberhead Levels, the Somerset Levels, North West Wetlands and East Anglian Fens.  However, they have received less attention and we need to promote awareness of their potential as evidence.

The Small Wetland Toolkit piloted a methodology for the rapid mapping and assessment of such assets for enhancing data about them in Historic Environment Records. Developed in Worcestershire, it focused on areas where these features are most under threat from development, land-use or environmental management. It aims to provide a readily accessible means of ensuring that such significant deposits are better identified and recognised, and thus more effectively protected in the future.

Another related project, "Small Wetlands; their potentials and threats" was begun within the plan period and will summarise the characteristics and research potential for different types of small wetlands and present an assessment of threats, from a national perspective. This will be aimed at public and professional partners.

Wetland sites and landscapes: publications

There are three publication projects nearing completion, reporting on survey and analysis for: the North West Wetlands, South Lancashire; the Somerset Levels; and Beccles Triple Post Alignment in Suffolk.

Photograph showing volunteers working with heritage professionals at a wetland site
Working with heritage professionals, volunteers helped to check the depth and character of organic deposits at a range of small wetland sites identified from map analysis as part of the 'Small Wetlands Toolkit' project. © Worcestershire County Council

Links to Other NHPP Activities

Wetland and waterlogged survey links closely with Activities on:

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