ARCA Geoarchaeology and PCA Winchester have been investigating deposits and assessing preservation conditions for areas of highest potential across the CWR site. 

Subsequently, ARCA have been undertaking detailed processing, description and preliminary analysis of the cores, to understand the deposit sequence across the CWR site. 

We have produced a video diary to give you a flavour of what we have been up to. To view the films click here (Update 1) and here (Update 2) and here (Final Update).

We hosted an Archaeology Day on the Central Winchester Regeneration site on Wednesday 6 October 2021. Keith Wilkinson from ARCA, University of Winchester, spoke to over 50 interested local residents on-site during an informal drop-in session. This was followed by an online presentation highlighting some of the findings so far, and a Q&A session with the Central Winchester Regeneration Archaeology Advisory Panel. View the presentation. ^{(pdf, 3.6mb)}

We also held an Archaeology Update session and Archaeology Panel discussion on Tuesday 26 July 2022 summarising findings from the works so far and the proposed next stage of works, with an opportunity for the public to ask questions. The meeting also sought endorsement from the Archaeology Panel on the proposed next steps, and this was granted. The council will therefore proceed with the proposed next stage, subject to budget approval.

A copy of the presentation can be seen here. ^{(pdf, 1.3mb)}

Spring 2022 Update

Since the last update on this project, the ARCA team have been undertaking a detailed analysis of the water monitoring data obtained across the CWR site between September 2020 to September 2021. An updated report integrating the results of the work with the data from the previous project phases (see the earlier summaries and reports), has now been received by the Council.

Although the presence of fluctuating groundwater below Winchester has long been known and some assumptions have been possible relating to this, the current project is the first to assess this in detail. The project results provide key insights into the water table below the CWR site and, crucially, how this interacts with buried archaeological remains. These insights also have wider relevance to other areas of the city.  

During the monitoring period, groundwater levels were found to vary between 1.5 – 2.9m below ground level, within archaeological deposits. These water levels are continually linked to the underlying principal Chalk aquifer (horizontally and vertically) and a secondary superficial aquifer in the Itchen Valley, with no evidence for any perched water table identified. Groundwater below the CWR area (and wider parts of Winchester) is largely influenced by regional processes within the groundwater catchment basin rather than being directly influenced by rainfall over the site itself. Seepage from the Itchen river and its tributaries (including the culverted stream immediately east of the CWR site) are likely minor contributors, affecting the very eastern part of the site only.

This water data has been combined and analysed against the previously obtained stratigraphic information and sedimentology, geochemical, biological and finds analysis, providing insights into preservation conditions below the site. The data suggests that, to some degree, preservation of organic material relates more to the context the material lies within and how that was formed, than in relation to groundwater (although this does have some bearing). Below the CWR site, preservation of organic remains within peat deposits (which can help tell us about past environments and climate) are likely to be related to a combination of factors such as compression and previous lower groundwater levels in the Early to Middle Holocene.

The project results indicate that organic preservation within archaeological levels are better preserved below present groundwater levels, but also that preservation levels are similar within the current fluctuating groundwater zone. Thus, unless there are substantial groundwater changes such as a reduction in groundwater level from local compartmentalisation (e.g. from basement levels), preservation of biological remains within archaeological deposits would be unlikely to be adversely affected by redevelopment. The greatest risk to organic archaeological remains is considered to be damage arising from construction rather than potential changes to groundwater. The report also highlights that removal of hard surfacing as part of future development will enable rainfall recharging of groundwater rather than this being removed from the site via the drainage system as currently occurs. 

The final report also contains an outline zoning of the CWR site based on the character, depth, thickness and preservation of archaeological and biological remains below the site and also notes that the assessment can be refined if dating of the deposits is obtained. This is something that the Council is currently considering.

Based on the project results, the Council in discussion with Historic England and ARCA has determined that there is no requirement to undertake further water monitoring or analysis, which had been planned as a potential second project phase. This final report, therefore, concludes the CWR geoarchaeological and hydrogeological project.

The project results have provided a clearer understanding of the character of buried deposits below the CWR site; their archaeological and palaeoenvironmental potential, and vulnerability to changes in the water environment. The findings will help to inform future redevelopment plans and guide the design of detailed archaeological evaluation trenching and research questions moving forward.

ARCA plan a scientific publication detailing the novel and ground-breaking approaches adopted by this project methodology, which Historic England comments has

“Successfully built on ‘standard’ geoarchaeological investigations, drawing on aspects of buried deposits (hydrogeology, biological preservation and geochemistry) rarely included in reports for commercial projects. There is little in the way of previous approaches to follow, which means the work done by ARCA on CWR sets the standard for future work on other sites. They’ve set a high standard!”

Summer 2021 Update

Although news on archaeology within the CWR site has been quiet recently, behind the scenes ARCA and other specialists in various fields have been undertaking analysis of samples taken from the cores drilled from the ground across the CWR area late last summer. The reports available on the next tab detail the background to the site and the results of the coring and previous assessment of the stratigraphy present below the site.

Tiny remains such as pollen spores and larger plant, insect and snail remains have been assessed, together with detailed analysis of sediments and geochemical markers. This is aimed at increasing our understanding of the general nature of deposits below the CWR site and the conditions in which archaeological remains may exist. This information will help to inform future archaeological investigations undertaken in relation to development proposals as they come forward.

Preliminary results of this scientific analysis suggest that preservation of biological remains within assumed archaeological levels is good to moderate, whilst evidence of human activity has been identified within underlying alluvial deposits in the centre of the site. This confirms what has been seen in other locations: that flood deposits continued to form within the CWR area even after the foundation of the Roman city. As detailed in a previous report, a deep channel has been identified in the area of Kings Walk, and the recent analysis has identified traces of human activity within the channel fills, indicating that this was active in the historic period. 

One highly significant outcome of the analysis has been the identification of a suite of geochemical markers which provide a pointer to sediments that are Roman or later in date. This is something that could potentially be used in the future to help identify the horizon between urban and pre-urban deposits elsewhere in Winchester (something that can sometimes be difficult to ascertain). The potential of this type of analysis may also extend beyond Winchester.

The next stage of the CWR project will analyse and report on the first year (of a possible multi-year) water monitoring project, linking this data with the previous stratigraphic, sedimentology, geochemical, archaeological and biological data. The aim is to assess risks to the preservation of archaeology, particularly waterlogged archaeology within the CWR area as a result of changing ground water levels. This will be of fundamental importance in determining, in conjunction with information from further archaeological investigations, what should happen to archaeological remains as a result of development proposals. 

The analysis undertaken so far provides a detailed insight into the different deposit types and their origin, nature, thickness and spatial distribution across the CWR area.

Beginning at the earliest geological era, there are indications of the development of an early north—south orientated channel within River Terrace deposits in the western part of the CWR area. These formed a basin within which alluvial and peat deposits built up, resulting in a swamp-like environment. A shallow channel seems to then have developed in the western part of the CWR area, within which deposits of tufa, also known from previous archaeological investigations in the area (notably at The Brooks Centre), have been found. The tufa was found to contain thin peat layers which could provide an opportunity to date the tufa below the centre of Winchester for the first time.

Further alluvial deposits subsequently built up, which are significantly thinner in the eastern part of the site. Again in the western part of the site, deposits from a borehole drilled in Kings Walk may suggest the development of a 4m deep channel which began to be infilled by alluvial deposits from the Roman period onwards. The presence of such a channel remains to be proven however.  

Archaeological deposits are then found over the entire CWR area, with the thickest deposits lying in the area of the bus station.  It is from this area also that indications of structural remains were recovered at varying depths in several of the boreholes - these include two waterlogged wooden stakes, layers of mortar and a wooden pile. Pottery ranging in date from the Roman, medieval and post-medieval periods, together with plant remains, bone and snail shells, was also recovered from the cores.

This picture is of course derived from small diameter boreholes, but the data so far obtained provides intriguing models and suggests the areas of highest potential. These will form the basis of research questions for subsequent, more detailed archaeological investigations as development proposals move forward. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copies of most recent technical reports can be found here:

Desk Based Assessment: CWR Geoarchaeological DBA August 2020 - Final ^{(pdf, 4.5mb)}

Stratigraphic Report: CWR Geoarchaeology Stratigraphic Interim Report October 2020 - Final ^{(pdf, 2.2mb)}

Integrated Geoarchaeological Report: CWR Integrated Geoarchaeological Report 2021 - Final ^{(pdf, 9.8mb)}

CWR Final Integrated Geoarchaeological Report - Mar 2022  Final Integrated Geoarchaeological Report Mar 2022.pdf 

 

A variety of modern archaeological techniques are available to developers including:

• Geoarchaeological borehole survey

to assess the earth, sediment and deposits on the site

• Hydrological assessment

to assess water flow, the water table and saturation levels

• Ground Penetrating Radar - a non-intrusive technique that may have the potential to see beneath the surface without digging, although water and below ground structures may create too much ‘noise’
• Shallow site investigations (such as for soil testing for foundation design) - these could be integrated into the wider evaluation programme with minimal impact to retrieve the maximum information
• Trial trenching - to provide key information as part of the evaluation of the site

Photographic and other records should be made in line with Historic England’s guidance. This would create a valuable record of the current Winchester townscape for future generations.

 

Victorian tobacco pipe find - 28 July

PCA Open Day Info - 28 July

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 CWR Archaeology Panel - 26 July

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Work starts on site - 17 July