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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.earscirev.2006.03.006 Byline: Joseph Holden (a), L. Jared West (b), Andy J. Howard (c), Eleanor Maxfield (d), Ian Panter (e), John Oxley (f) Keywords: groundwater; organic deposits; preservation; redox; hydrological connectivity; archaeology; subsurface processes; hydrology Abstract: Environmental change caused by urban development, land drainage, agriculture or climate change may result in accelerated decay of in situ archaeological remains. This paper reviews research into impacts of environmental change on hydrological processes of relevance to preservation of archaeological remains in situ. It compares work at rural sites with more complex urban environments. The research demonstrates that both the quantity and quality of data on preservation status, and hydrological and chemical parameters collected during routine archaeological surveys need to be improved. The work also demonstrates the necessity for any archaeological site to be placed within its topographic and geological context. In order to understand preservation potential fully, it is necessary to move away from studying the archaeological site as an isolated unit, since factors some distance away from the site of interest can be important for determining preservation. The paper reviews what is known about the hydrological factors of importance to archaeological preservation and recommends research that needs to be conducted so that archaeological risk can be more adequately predicted and mitigated. Any activity that changes either source pathways or the dominant water input may have an impact not just because of changes to the water balance or the water table, but because of changes to water chemistry. Therefore, efforts to manage threatened waterlogged environments must consider the chemical nature of the water input into the system. Clearer methods of assessing the degree to which buried archaeological sites can withstand changing hydrological conditions are needed, in addition to research which helps us understand what triggers decay and what controls thresholds of response for different sediments and types of artefact. Author Affiliation: (a) Earth and Biosphere Institute, School of Geography, University of Leeds, Leeds, LS2 9JT, UK (b) Earth and Biosphere Institute, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK (c) The Institute of Archaeology and Antiquity, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK (d) Environment Agency, Rio House, Aztec West, Bristol, BS32 4UD, UK (e) English Heritage, 37 Tanner Row, York, YO1 6WP, UK (f) City of York Council, The Guildhall, York, YO1 9QN, UK Article History: Received 10 November 2005; Accepted 27 March 2006

This paper examines the Roman boat, buried beneath Guys Hospital in London, UK. A small part was discovered in 1958, and has been carefully left free of disturbance since that date. In 2009, a proposal was made to construct a 14-storey building above the boat; clearly raising challenges for preservation, not to mention the philosophy of burying or excavating and entire ancient monument. A trial pit was opened to see if any remains of the boat survived and uncovered well-preserved timber planks and nails preserved five metres below ground level. Consequently, archaeologists worked closely with the entire design team, determined that more was required than the usual scheme of preserving and monitoring the boat. A legal agreement was secured, making this one of the few projects in the world to have a clearly structured and enforceable plan, if the monitoring data show demonstrable deterioration. [ABSTRACT FROM AUTHOR]

A baseline survey in 2007 characterized the physical and chemical conditions for preservation within waterlogged remains at Nantwich. Installation of eighteen dipwells has allowed a five-year monitoring programme to be conducted from 2011. Two add-on projects supplemented this monitoring programme by examining the different methods for redox measurement, and for soil moisture measurement using Time Domain Reflectometry (TDR). Initial results show two main zones of preservation, with reducing conditions attributed to location of the deposits in the floodplain, and a second zone uphill with more variable conditions for preservation. This study shows that sediment-coring programmes combined with dipwell installations can provide useful data to assess and monitor in situ preservation conditions, which can help to formulate management strategies for conservation of waterlogged archaeological deposits. This paper focuses on the efficacy of the methodology, referencing in particular comparative monitoring techniques and lists a series of recommendations for future studies. [ABSTRACT FROM AUTHOR]

IT HAS BEEN accepted for many years that, unlike their silver counterparts, pewter chalices and patens found in priestly burials continued largely unchanged in form throughout the medieval period; this means that the presence of a pewter chalice or paten does not in itself currently offer any reliable dating of a related burial beyond a broad 13th–16th-century timeframe. Pewter chalices and patens recovered from 25 burials within York Minster between 1966 and 1973 are thought to represent the largest collection found within one church in England, and initial assessment of this collection and its related excavation data indicated that it offered the possibility of providing findspots for some of the vessels from recorded burials or dated archaeological sequences, and thus to provide more examples of tightly drawn dating. In the event, it has been possible to assign a single chalice and paten set to a recorded individual, and to provide others with periods within which, or after which, burial occurred. Scrutiny of the objects also resulted in the identification of two distinct forms of paten, one of which was shown in seven instances to bear incised motifs which had not been noted or commented upon previously. [ABSTRACT FROM AUTHOR]

This paper will outline the approach taken for monitoring of two waterlogged areas in England: the multi-period deposits beneath the historic town of Nantwich, Cheshire, and the Bronze Age timber platform at Whittlesey, Cambridgeshire. These two examples allow contrast and comparison between urban and rural contexts, and between multiple ownerships and single development. The projects also illustrate how English planning guidance can be variously interpreted dependent on conflicting aims and objectives. The paper will describe the characteristics of the sites, their past history and present threats, and the suggested management strategies for each. The duration, spatial interval, and methods of monitoring (including use of In Situ redox probes, Time Domain Reflectometry, sediment geochemistry, and water-level measurement) will be discussed, and how short-term data-gathering is actually what influences decision-making. [ABSTRACT FROM AUTHOR]