Pollution control & water quality • Biodiversity & conservation importance • Palaeoecology & Archaeology • Designations & conservation management

Archaeology

As noted in the section on palaeoecology, saltmarsh sediment sequences often overlie a surface that was dry land before rising sea-level led to its submergence and, eventually, burial under silts, clays and peats. Buried soils (‘palaeosols’) frequently include artefacts dating to the early post-glacial, around 10,000 years ago, and at some locations well-preserved prehistoric occupation sites occur. Later sites and artefacts related to transportation, fisheries, salt production and other coastal activities preserved within the sediments overlying this land surface. Organic materials, particularly wood for example, are well-preserved in anoxic saltmarsh sediments.

As illustrated by the examples below, erosion exposes sites that would otherwise remain unknown, however it can eventually result in site destruction. English Heritage is therefore currently commissioning a series of Rapid Coastal Zone Assessment Surveys, intended to record eroding sites and to provide information that can be fed directly into the development of Shoreline and Estuary Management Plans, coastal strategies and coastal management schemes. The survey data are being incorporated into Local Authority Historic Environment Records (HER) and the English Heritage's National Monuments Record (NMR). Both are GIS data-bases which can be accessed by members of the public and shoreline managers. However, any survey simply provides a ‘snap shot’ of what was visible at a particular time, and it is impossible to maintain a monitoring programme everywhere. Reports of sites newly exposed by erosion are, therefore, very welcome. Managers of coastal reserves and other sites are particularly well-placed to observe and report new finds. In almost all cases, recording eroding sites will involve minimal intervention and will entail drawing and photographing naturally-eroded sections and collecting artefacts and small sediment samples for dating or palaeoecological analysis.

Sites can also be damaged or destroyed by shoreline management schemes, such as managed realignment. Any ground-works, including excavation of borrow-dykes for new sea-walls or for the re-instatement of former creeks within realigned areas, can be damaging. However it may be possible to preserve sites in situ by relocating proposed works. For example, Late Iron Age or Roman salt-producing sites (‘Red Hills’) were known to be present in the realigned area at the Essex Wildlife Trust Reserve at Abbot’s Hall, Great Wigborough. Damage to these sites was avoided by slightly relocating planned drainage channels. In other cases preservation may not be possible, but full recording before sites are destroyed is usually considered to be acceptable mitigation.

For more information on archaeology and saltmarshes the reader is refered to Flemming (2004) and Fulford et. al. (1997).

For further information see www.english-heritage.org.uk under Public Policy>Coastal Policy. For advice, or to report a newly-exposed site, contact the appropriate County Archaeologist (usually located in the County Council Planning Department), the English Heritage Regional Office or Peter Murphy, Coastal Strategy Officer, Maritime Team, English Heritage, Fort Cumberland, Eastney, Portsmouth PO4 9LDpeter.murphy@english-heritage.org.uk.

Click on the links below for examples of eroded saltmarsh and exposed Archaeological finds:

Canewdon, Essex - Bronze Age wooden paddle.
South Woodham Ferrers, Essex - Bronze Age salt-evaporating hearth.
The Stumble, Blackwater Estuary, Essex - Severe erosion.
The Stumble, Blackwater Estuary, Essex - Part of an Iron Age hurdle bridge.
Purfleet, Essex - flint and Cornish Greenstone axes.
Packing Marsh Island, Essex - 19th Century oyster fishery.