14. Archaeology and the historic environment
Who does what?
Stated Government aims
Background
The Severn Estuary is well known for the wealth of features of archaeological importance and historic interest. Its archaeological potential is not fully represented by the number of nationally designated Scheduled Ancient Monuments or sites recorded in Regional Sites and Monuments Records, as many sites which are sealed within the accumulation of marine sediments and peats which make up the Severn Levels, still await discovery.
Archaeological evidence recovered from the intertidal zone points to the full potential of the area, with finds reflecting the presence of settlement sites; fords, ports and landing places; fish weirs and traps; derelict drainage systems; wooden trackways; sea defence embankments. The area demonstrates what is by far the greatest concentration of coastal archaeology in Britain. Of exceptional importance for British maritime heritage are recent discoveries of Bronze Age, Roman and Medieval boats.
What makes the estuary particularly important is that many of the deposits are waterlogged, preserving organic evidence such as wood and evidence of past environments. Studies of pollen, plant remains, beetles and the sediments themselves show how the estuary has evolved through time. The sedimentary and environmental sequence from the estuary is of exceptional quality and length.
Palaeolithic handaxes and Mesolithic footprints and stone tool scatters recovered from the foreshore indicate the presence of hunter-gatherer groups before the introduction of farming. Later prehistoric sites include the Bronze Age settlement at Brean Down, roundhouses recorded on intertidal peats of the Gwent Levels, and a deeply buried site at Caldicot where relict silted river channels contained the remains of fords, fish traps, bridges and boats. A concentration of rectangular buildings connected by a system of trackways recently excavated in the intertidal area near Goldcliff, and dating back to the Iron Age, is unique.
Roman settlement in the area saw the first systematic attempt to manage the estuary through the construction of drainage systems and seabanks along the north shore in Gloucestershire, in the North Somerset Levels and on the Wentlooge Levels. Some of the evidence for coastal settlement has been lost through erosion by the sea but artefacts and environmental evidence point to: widespread trade in iron ore, from the Forest of Dean; trade in pottery, from south-east Dorset; and agricultural activity including the production of cereals on the coastal plain. The recent discovery of a near-complete boat at Barland's Farm, Magor may indicate the kind of craft which worked the estuary at this time.
During the centuries after the end of Roman rule, many of the sea defences around the Severn Levels broke down. The recolonisation of the wetlands began in Somerset in the Saxon period, but followed on later in the Gwent Levels, probably from the eleventh to thirteenth centuries. The complex systems of land division, characterised by open drainage ditches developed behind new sea walls. These sea walls were moved inland in the fifteenth century in response to increased storminess which had led to considerable coastal erosion. Much of the present landscape of the Severn Levels owes its origins to the monks of the medieval period, and reflects the efforts of successive generations of farmers to manage and exploit the coastal margins of the estuary.
The estuary allowing such an easy access point deep into the western half of the British Isles, necessitated the construction of strategic defences for protection during times of war. The most impressive of these features date from both the Napoleonic and 2nd World Wars, with fortified defences on both Flat Holm and Steep Holm and other promontories in the lower estuary, most notably Brean Down and Lavernock Point. Some of the Napoleonic gun emplacements are scheduled Ancient Monuments.
It must be stressed that whilst many sites of archaeological important and historic interest are known and recorded it is likely that other sites remain undiscovered. The potential for loss and disturbance of the archaeological and historic landscape resource is great, with ground disturbance caused by all kinds of development, lowering of the water table and agricultural improvements leading to the filling of gripes and field boundary ditches, under drainage and the ploughing of earthworks. These latter features including ridge and furrow, settlement related earthworks and the sea walls themselves, tend to be overlooked whereas they play a key role in defining the landscape of the Levels.
The historic importance of the landscape has been further recognised by the Countryside Council for Wales/ Cadw funded Gwent Levels Historic Landscape Study, and by similar research being done on the Somerset Levels funded by English Heritage. The Roman drainage system still found on the Wentlooge Levels, and the 900 year history of medieval and later drainage patterns provides a living historical landscape.
Map 14: Scheduled Ancient Monuments
Issues
Many issues in this report are related to one another. Issues raised in this chapter have particular links with those in chapters 3, 5, 9, 12, and 15.
H1 The threat to archaeological sites from development.
Increased development around the estuary and particularly on the Levels is threatening the archaeological resource. Pressures come from all types of development - tourism, leisure, port-related, industrial/ commercial parks, town and village expansion and the associated infrastructure. Future development where there may be a potential conflict include those areas associated with the Second Severn Crossing in the Caldicot and Rogiet area, and large developments such as the new Lucky Goldstar factory at Newport.
Who is involved: Planning authorities and developers, Cadw, English Heritage and the local archaeological trusts.
What is happening: The DoE's Planning Policy Guidance note 16 provides a framework for archaeology in relation to development plans and proposals. Similarly PPG Wales and relevant Technical Advice Notes (WO Circulars 60/96, 61/96) give guidance on such matters for Wales.
Some suggestions: Further research could be undertaken to improve prospecting and detection of buried archaeological sites in the Levels leading to improvement of the database. More research could also be undertaken on activities which are likely to have a detrimental effect on important archaeological resources and its findings disseminated more widely.
H2 Damage to archaeological heritage caused by erosion
Changes in the sediment pattern and an increase in erosion is revealing a suite of archaeological sites. Erosion of the foreshore in the last few years has revealed three new bronze age sites in the intertidal zone at Rumney Great Wharf yielding cobbles, pottery fragments, animals bones and teeth and charcoal fragments. These are examples of a number of sites which are undergoing very active erosion, a problem which may increase with a rise in sea level. Exposed sites are particularly vulnerable to damage from human activities such as development and natural processes such as waves.
Who is involved: Planning authorities and developers, Cadw, English Heritage and the local archaeological trusts.
What is happening: Additional observation and recording of sites as they are exposed is being carried out by local archaeological trusts and university researchers from Reading, Exeter, Bristol and University of Wales Lampeter.
Some suggestions: The monitoring of erosion rates, particularly of the peat edges, will increase knowledge of how quickly information is being lost.
H3 Effects of water level changes on archaeological remains
Saturated soil and peat tends to preserve archaeological remains better than dry soils because the water prevents the normal processes of aerobic decay which degrade the organic parts and associated environmental evidence. Water abstraction and drainage can affect the water table and hence the preservation of archaeological remains.
Who is involved: Environment Agency, local authorities, internal drainage boards, landowners, Cadw and English Heritage.
What is happening: Water level management plans are being prepared for all water dependent SSSIs such as the Gwent and Somerset Levels. Research is being carried out on the Somerset Levels funded by English Heritage.
Some suggestions: Similar plans could be considered for other important archaeological areas.
H4 Inadequate information about, and awareness of, the archaeology of the estuary.
The estuary contains a wealth of archaeological remains but only a relatively small part of it has been properly surveyed. The distribution of sites recorded in regional Sites and Monuments Records and/ or protected as Scheduled Ancient Monuments does not reflect the true density of sites sealed in the Levels. Without a good knowledge of the resource it is difficult to protect it on a strategic rather than site by site basis. Information about the intertidal area is particularly scarce although some work has been done, such as the Severn Estuary Intertidal Peat Survey being carried out along a 25km stretch of estuary between Cardiff and the Second Severn Crossing.
Many users of the estuary are therefore unaware of the importance of the archaeology of the estuary and this leads to accidental damage.
Who is involved: Local authorities, English Heritage, Cadw, National Museums and Galleries of Wales, local archaeological trusts, universities and other agencies.
What is happening: Considerable research is being carried out, and information disseminated.
Some suggestions: Consideration could be given to undertaking more surveys of the estuary as a whole and of the inter-tidal area in particular. This information could be made more widely available to decision makers and users of the estuary.
H5 Potential effects of sea defence works on undiscovered archaeological sites
See issue C5 in chapter 5.
H6 Protecting the historic landscape of the Severn Levels
The present landscape of the Severn Levels reflects centuries of management of the area by successive generations of landowners. In addition to being highly valued as an attractive area, the landscape character and its component features are part of the archaeological resource. Alterations to this system of land and water management have archaeological impacts which need to be addressed and assessed.
Who is involved: English Heritage, local planning authorities, Cadw, Countryside Commission, the Countryside Council for Wales, Environment Agency, landowners and Internal Drainage Boards.
What is happening: The importance of the drainage system as part of the landscape has been recognised as part of the Cadw/ ICOMOS/ Countryside Council for Wales consultation document: the Register of Landscapes, Parks and Gardens of Special Historic Interest in Wales.
Some suggestions: Landowners and occupiers could be encouraged to manage the land to protect this important landscape. Consideration could be given to ways in which grant aid can be made available to give more support.