New tools at Avebury

Although significant to societies at a local, regional and national level for up to 6000 years, the prehistoric landscape of Avebury, Wiltshire, was formally attributed the accolade of being 'globally important' in November 1986. At this time the United Nations Educational, Scientific and Cultural Organisation (UNESCO) inscribed Avebury onto the growing list of World Heritage Sites, and along with England's most notorious prehistoric monument, 'Stonehenge, Avebury, and associated sites' (C373) was created.

The joint nomination of both Avebury and Stonehenge by the UK government was rational. At a time when no UK sites were on the list, seven UK applications were being presented to UNESCO and it was considered that there would be a better chance of both landscapes being accepted if they were considered as one site. Indeed, in comparison with the variety of cultural and temporal variation in nominations, Stonehenge and Avebury are similar. It is true that upon closer inspection there are both comparable and contrasting patterns of monument type, construction, use and disuse, but when comparing these differences to those between here and Durham Castle or Ironbridge Gorge, for example, Stonehenge and Avebury certainly have an affinity.

However, the two landscapes are over 20 km apart, which presents problems when approaching the management and study of the cultural environment. Between the two areas lies the broad Vale of Pewsey and the upland of Salisbury Plain which has meant that, to consider the World Heritage Site effectively, two boundaries have been delineated, one for each landscape. This has some advantages. Further to their geographical separation, very different situations have arisen at both sites. For example, Avebury has a village community at the heart of the landscape whereas Stonehenge is more isolated from settlements. However, Stonehenge is troubled by busy roads and the impact of a concentration of visitors on one very small patch of ground. The creation of two boundaries has meant that it is possible, when necessary, to consider them separately.

The production of Management Plans has been one such occasion and Avebury has been the first of the two to pass through this process (Pomeroy 1998). This is not unique to UK sites and follows previous plans for Hadrian's Wall (1996) and Greenwich (1997). What has been unique at Avebury, however, is the construction of a spatial database alongside, and as part of, the formulation of the Management Plan. The construction of the Avebury WHS Geographical Information System (GIS) has been established with the aim of integrating data already held by various bodies, recording information resulting from the production of the plan, helping to formulate decisions and, most importantly, becoming a fundamental tool in aiding the implementation of any recommendations.

The database has been developed in consultation with the Avebury WHS Steering Committee and Avebury Archaeological and Historical Research Group, by English Heritage at its Centre for Archaeology. A GIS study area of 13x12 km has been chosen an area much larger than the limits of the WHS boundary at Avebury. The rationale behind this is that while the focus is on the World Heritage Site, decisions need to be based upon, and give consideration to, the broader landscape.

Many layers of spatial information have now been integrated, most important of which have been data from the Wiltshire County Sites and Monuments Record. These have also been enhanced by additional archaeological information from English Heritage's National Mapping Programme. Further archaeological data include layers indicating areas of various types of survey, and there are currently plans to include an excavation database. Underlying these are two Ordnance Survey 1:10000 datasets: a raster base map and the Landform Profile contour data. Using the contour data, a digital elevation model (DEM) has been created and subsequently used to study visibility and visual relationships within the landscape (Figure 1, above).

During the formulation of the Management Plan, studies were commissioned which have produced both a landscape assessment and a traffic and visitor study. These have resulted in new datasets, such as land use and areas of visitor pressure, which have been recorded in the GIS and then used along with the archaeological information to help support the formulation of the plan. This support has included, for example, the provision of statistics on the current land use of monuments, the distribution of scheduled archaeology and the production of figures for publications.

Since the launch of the Management Plan, an Implementation Officer, based at Kennet District Council, has been in place. Alongside her sits the Avebury WHS GIS, which is used regularly to support the daily work of implementing those recommendations made in the plan. The database is also used to absorb the results of this implementation. For example, a monument condition survey has recently been carried out within the World Heritage Site, the results of which are easily attached to the existing archaeological information relating to each monument concerned (Figure 2, below). The ability of the GIS to attach multimedia data to these sites, such as photographs, video, html reports and scanned drawings, means that the photographs taken as part of the condition survey can be referenced and viewed readily.

As the Plan is implemented so the effectiveness of the GIS as a monitoring tool will increase, as it will be able to be used for the comparison of data collected over a number of years. In addition to this its use will be extended for other purposes. It is already currently assisting in the formulation of a research agenda for the WHS, as well as providing advise in development control cases, and with another exciting season of research in the area this summer, it will be able to aid with these projects too.

References

• POMEROY, M. 1998. Avebury World Heritage Site Management Plan. London: English Heritage.