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This paper considers the application of deposit modeling within archaeological projects, summarizing the results of a Historic England funded project aimed at developing "good practice" for the application of these techniques within terrestrial environments. It provides an overview of what deposit modeling is, the environments where it can be used and the methods most commonly used. The paper identifies a series of issues and challenges in using deposit models within archaeological investigations, such as the archiving of geotechnical data, the testing of deposit models against the distribution of archaeological sites and features, and integrating sediment stratigraphies derived from deposit modeling with post‐excavation records. We argue that deposit modeling is a valuable tool for archeologists to employ and can be used to design appropriate excavation strategies to target sites and features, thereby increasing the information yield of a project. In this sense deposit modeling can be used as a framework for archaeological projects that are investigating sediment sequences in complex geomorphological environments, starting with pre‐evaluation data gathering, through to focusing excavation strategies, and within the post‐excavation analysis. Whilst this paper is focused upon the terrestrial archaeological record, the themes discussed have resonance for archaeological records across the globe, including the offshore zone. [ABSTRACT FROM AUTHOR]

Lidar has become an essential tool for the mapping and interpretation of natural and archaeological features within the landscape. It is also increasingly integrated and visualized within geoarchaeological deposit models, providing valuable topographic and stratigraphic control from the contemporary ground surface downwards. However, there is a wide range of methods available for the visualization of lidar elevation models and a review of existing research suggests that it remains unclear which are most appropriate for geoarchaeological applications. This paper addresses this issue by providing an overview and quantitative evaluation of these techniques with examples from archaeologically resource‐rich alluvial environments. Owing to the relatively low‐relief nature of the terrain within these temperate lowland flood plain environments, the results show that there is a small number of visualization methods that demonstrably improve the detection of geomorphological landforms that can be related to the variable distribution of archaeological resources. More specifically, a combination of Relative Elevation Models combined with Simple Local Relief Models offered an optimal approach that subsequently allows integration with deposit models. Whilst the presented examples are from a flood plain setting, deposit models are pertinent to a range of landscape contexts and the methodology applied here has wider applicability. [ABSTRACT FROM AUTHOR]

The impacts of both summer and winter flooding have been acutely felt across the inland areas of the UK over the last decade and under scenarios of future climate change, such events are likely to become more commonplace. Whilst significant emphasis is inevitably placed during such emergencies on securing basic major infrastructure (transport, power and water), there is also a need to consider how best to protect the Historic Environment. A recent Historic England funded project undertaken by the authors has sought to map the distribution of historic sites against known flood hotspots in Worcestershire to create a GIS resource tool for use by emergency planners and other non-heritage specialists. In addition to the development of a project GIS, a number of further studies were undertaken to consider best practice for flood alleviation, explore the impacts of past events on infrastructure and communities, and the building of resilience through community action. During the lifecycle of the project, a number of key issues and challenges were identified with respect to mitigating and managing the impacts of flooding upon the Historic Environment, before, during and after such events. The Met Office’s decision to begin naming severe storms from the autumn of 2015 and the associated devastating impacts of early examples, such as ‘Desmond’ and ‘Frank’ are leading to an ever-increasing focus on extreme events; therefore, the themes explored in this paper have resonance beyond the administrative boundaries of Worcestershire and are presented within the broader framework of environmental management. [ABSTRACT FROM AUTHOR]

The River Trent, UK, is renowned for a rich palimpsest of alluvial archaeological remains buried within the Holocene sands and gravels of the valley floor. Since the late 1990's extraction of these postglacial deposits at Shardlow quarry in the middle reach of the valley, close to the confluence of the River Trent and River Derwent, has been investigated and monitored on a weekly basis by a project team including geoarchaeologists. Such monitoring of large exposures of floodplain sand and gravel and adjacent Pleistocene terrace deposits, initially by volunteer activity, but latterly, funded by the aggregate company under a formal planning agreement, has revealed significant alluvial archaeological remains including two logboats, a possible brushwood platform, several fish weirs and organic-rich palaeochannel deposits. This paper provides a summary of the wealth of this resource, but also reflects on the challenges of undertaking geoarchaeological studies in complex alluvial environments over such an extended time period. It concludes by providing advice for best practice that could be applied to other long term studies within similar environments. [ABSTRACT FROM AUTHOR]

Future climate change is likely to pose significant challenges for heritage management, especially in landscape settings, such as river valleys as the magnitude, intensity and nature of geomorphological processes alter in response to changing threshold conditions. Industrial landscapes afford particular challenges for the heritage community, not only because the location of these historic remains is often intimately linked to the physical environment, but also because these landscapes can be heavily polluted by former (industrial) processes and, if released, the legacy of contaminants trapped in floodplain soils and sediments can exacerbate erosion and denudation. Responding to these challenges requires the development of methodologies that consider landscape change beyond individual sites and monuments and this paper reports the development of such an approach based on investigation of the Derwent Valley Mills World Heritage Site, Derbyshire, UK. Information on geomorphological evolution of the Derwent Valley over the last 1000 years, a time period encompassing the last two periods of major climatic deterioration, the Medieval Warm Period and Little Ice Age, has been dovetailed with archaeological and geochemical records to assess how the landscape has evolved to past landscape change. However, in addition to assessing past evolution, this methodology uses national climate change scenarios to predict future river change using the CAESAR-Lisflood model. Comparison of the results of this model to the spatial distribution of World Heritage Site assets highlights zones on the valley floor where pro-active mitigation might be required. The geomorphological and environmental science communities have long used predictive computer modelling to help understand and manage landscapes and this paper highlights an approach and area of research cross-over that would be beneficial for future heritage management. [ABSTRACT FROM AUTHOR]

Throughout the Quaternary, episodes of glaciation and associated low sea level have resulted in the connection of the terrestrial landmasses of Britain and mainland Europe. The river systems that established themselves across these newly emergent land surfaces of the coastal plain would have created important migration corridors for both animals and humans, a point corroborated by the affinity of Palaeolithic remains across Britain and Europe. Technological developments within the last decade have allowed these now submerged valley floors and adjacent terrestrial landscapes associated with the last cold stage and early and middle parts of the current (Holocene) interglacial to be explored and their archaeological legacies unravelled, providing geoarchaeologists with an opportunity to contribute to major cultural debates. However, in order to maximize knowledge, it is essential that geoarchaeologists working within river valleys across both Britain and the European continent are addressing similar research questions by collecting data using comparable methodologies. This paper reviews the approach taken in different regions and provides a baseline assessment to allow the development of a coherent European-wide framework for alluvial geoarchaeology and geoprospection, particularly with respect to the Holocene record. [ABSTRACT FROM AUTHOR]

Contemporary global metal mining is a source of environmental pollution, but in Britain it is our historic mining industry that has left a legacy of contamination in the landscape, around both the immediate mine sites as well as within the river valley floors that drain these orefields. It has been estimated that the levels of lead and zinc stored within some northern British river systems represent values comparable to present-day reserves of economically viable ore deposits and exposure to them can be detrimental to human health. Despite the prevalence and significance of these deposits, they have been neglected by the cultural heritage community in favour of more easily interpretable remains such as mine buildings, technologies of ore procurement and processing, and the final products of manufacture. This paper argues that in light of future climate change and legislation associated with the European Union Water Framework Directive, heritage managers and industrial archaeologists have to start investigating these deposits as part of their studies and to engage with the environmental science and geomorphological communities who are, at present, setting the agenda in terms of strategies for pollution mitigation and landscape remediation. [ABSTRACT FROM AUTHOR]

It is now widely acknowledged that human adaptation of the planet is causing significant changes to the global climate, which are being felt currently and are likely to increase in the future. This is beginning to place exceptional strains on the historic environment, here defined as both above and below ground archaeological remains. Using examples from the cultural list of World Heritage Sites in mainland Britain, this paper explores how knowledge of past and contemporary geological and geomorphological processes can provide an understanding of natural hazards and risk assessment. This, in turn, can inform management strategies to allow the protection and stabilisation of sites, limit further degradation and ensure long-term sustainability. From the analysis of published documentation available from UNESCO, it appears that natural processes have not always received the attention they deserve, and in some cases appear to have been ignored. Given the complexity of future climate change and the role that natural processes will play in determining the vulnerability of individual heritage assets, it is essential that geoscientists, archaeologists and cultural heritage managers work together to develop appropriate strategies to mitigate the effects of change in the future, especially since many of the themes developed in this paper have generic applicability across a range of landscape environments. [ABSTRACT FROM AUTHOR]

Abstract: Multiple sequences of radiocarbon dates extracted from organic materials are increasingly being used to provide robust chronologies for landscape development, particularly the timing and correlation of significant climatic and ‘process’ events. Whilst the validity of using such frameworks in sedimentary environments such as lake basins and raised bogs has been the focus of much attention, such debates have not extended to fluvial systems. Using examples from three lowland, vertically accreting river valleys in East Anglia, UK, this paper assesses the robustness of their associated radiocarbon chronologies by assessing the contrasting age estimates that are obtained by dating different parts of the same organic sample (humic, humin and plant macrofossils) at a variety of stratigraphic levels. Overall, the humin and humic acid fraction results were statistically consistent, whilst the plant macrofossil remains were found to be of a slightly younger age. In these examples, it is argued that the younger ages appear to be the result of Phragmites (common reed) roots pushing plant macrossils through the sedimentary sequence or opening up voids for material to fall through, although studies in lacustrine and mire environments suggest alternative explanations may also be possible. Whichever explanation is preferred, this study demonstrates clearly that the complexity of valley floor stratigraphy and processes is such, that using single radiocarbon dates, whether AMS or bulk samples to reconstruct chronologies of ‘geomorphic system response’ may need to be refined and subjected to the same level of assessment that has been applied in other sedimentary systems. [Copyright &y& Elsevier]

Environmental change caused by urban development, possibly augmented by climate change, may result in accelerated decay of in situ archaeological resources. Damage may be related to changes in hydrological processes. Such archaeological resources have to be considered in environmental planning. In this paper we highlight the need for improved hydrological data from urban archaeological sites using the case study of the City of York, UK, arguably one of the most well studied and well preserved urban archaeological environments globally. We suggest that the quality of hydrological data collected during routine surveys and experimental work must be improved and standardised in order for us to produce reliable archaeological risk models for urban sites. [Copyright &y& Elsevier]

Abstract: This paper reviews the Pleistocene evolution and human occupation of the River Trent, the major fluvial artery draining Midland Britain, and places it within a modern Quaternary context. In contrast to the sedimentary records of the River Thames and the erstwhile Bytham system, which extend back to the early Pleistocene, present knowledge of the terrace sequence of the Trent, its tributary systems and associated ancestral courses extends back only to the Anglian glaciation (Marine Isotope Stage (MIS) 12), although the regional pre-Anglian drainage configuration is demonstrably complex. The post-Anglian sequence is well developed, with major terrace sand and gravel aggradations associated with each subsequent cold stage. Temperate-climate sediments correlating with MIS 7 and 5e have been recorded, although deposits relating to earlier interglacials during MIS 11 and 9 have yet to be identified. Evidence for human occupation in the form of Lower and Middle Palaeolithic artefacts has been recorded from terrace sediments correlated with MIS 8 and MIS 4, but the majority of this material is heavily rolled and abraded, suggesting significant reworking from older deposits. This review demonstrates that there is a rich palaeo-environmental record from the Trent but the lack of a high-resolution chronostratgraphic framework raises issues about correlation with other systems. [Copyright &y& Elsevier]

Using examples from dated alluvial deposits in the Trent basin, UK, this paper suggests that the waterlogged remains of insects, mainly beetles, can be used to detect the occurrence of varying discharge and changing patterns of flood-plain evolution in low gradient alluvial landscapes of Holocene age. This approach may provide invaluable data where the finer-grained nature of sedimentation means that other types of information such as coarse boulder berms are lacking. Comparison of Coleoptera assemblages from three high-energy and two lower-energy deposits indicates that a number of distinctive characteristics can be identified and criteria can be set for the distinction of these two contrasting depositional environments. This approach is tested using Coleoptera remains recovered from a palaeochannel fill at Spalford Meadows in the Lower Trent Valley. The application of this methodology could contribute to the reconstruction of river histories, a key factor in understanding the distribution of valley floor archaeological settlement patterns. [Copyright &y& Elsevier]

Temperate river systems cover large regions of the earth's surface and provide challenging environments for the detection of archaeological remains. The deposition of alluvium above, and interbedded with, archaeological deposits means conventional forms of archaeological prospection such as geophysical survey or aerial photography are often ineffective. Consequently, archaeologists have turned to the construction of deposit models to evaluate the archaeological potential of various landforms. However, despite the high capacity of satellite multispectral data to identify alluvial landforms and archaeological deposits, the contribution that it can make towards deposit models has only received limited attention. This research assesses the capability of higher resolution satellite multispectral imagery to identify alluvial landform assemblages and subsequently facilitate the modelling of geoarchaeological resources. As image enhancements are often required to improve interpretation or classification, it includes a quantitative evaluation of 45 different processes, comprising two spectral separability measures on paired regions of interest (ROIs) from the Lower Lugg Valley, Herefordshire, UK. The results define optimal image processing techniques for the detailed geoarchaeological interpretation of alluvial environments and demonstrate that relatively simple visualisation methods (e.g. composite images) and summative techniques (Principal Components Analysis) offer some of the most effective approaches. • Alluvial environments present challenging conditions where standard archaeological prospection methods are inappropriate. • Higher resolution satellite multispectral imagery can be used for the modelling of geoarchaeological resources. • A significant number of image enhancement procedures are evaluated through two spectral separability tests. • Results indicate that CIR and PCA composites, offer the most effective methods for the investigation of temperate alluvial environments. [ABSTRACT FROM AUTHOR]

Abstract: The analysis and preservation of organic materials preserved within wetland environments represents one of the most costly parts of any post-excavation strategy. This paper outlines the application of high-resolution terrestrial laser scanning to one class of preserved material, worked archaeological wood. Scanning allowed the recording of the artefacts in three dimensions and the identification of features such as toolmarks. Features can be measured and volumetrically modelled within the digital environment, which may not always be possible for these often fragile materials using conventional techniques. Repeat scanning of the artefacts provided an opportunity to use comparative analysis software to investigate changes in the morphology of artefacts under contrasting conditions of short-term storage. The results suggest that immersion in water results in the least deterioration, whereas both freezing and air-drying caused distortion and degradation. This paper demonstrates that laser scanning provides a viable alternative post-excavation method for the recording, analysis and long-term ‘virtual archiving’ of organic archaeological materials, which may be more cost-effective in some instances than other methods of preservation. [ABSTRACT FROM AUTHOR]

This paper outlines the use of geographical information systems for predicting the possible implications of future climate change (as suggested by General Circulation Models) on the archaeological resource of selected parts of two major British river systems, the Trent and Yorkshire Ouse. The effects of future climatic change on the historic environment are likely to come from both natural 'system' responses, such as increased bank erosion and valley floor sedimentation, as well as the human adaptive responses selected to manage the impacts of climate change. The models described in this paper allow predictions to be made and quantified about how selected natural and anthropogenic responses may impact upon the archaeological resource. Such approaches, which are relatively rapid to implement and low cost, provide an important management tool for guiding policy makers and heritage managers in the face of changing climates. [ABSTRACT FROM AUTHOR]

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. [Copyright &y& Elsevier]

The recently published Mineral Extraction and Archaeology: A Practice Guide (English Heritage, 2008) identifies the use of geomorphological mapping and specialist remote sensing technologies allied to other techniques as important tools for use in the investigation of deeply buried archaeological sites. Such approaches are particularly valuable within environments like river valleys where prospection is particularly difficult due to the masking effect of alluvium; however, some of these techniques are unproven in several major river catchments where aggregate extraction is significant and they have yet to be widely integrated in commercial practice as part of the planning process. Methodological approaches using these techniques have largely been developed since 2002 through a number of research projects supported by the Aggregates Levy Sustainability Fund (ALSF) and English Heritage. They focus on enhancing understanding of the geoarchaeological and chronological development of river valley floors and thus the environment(s) within which archaeological sites have developed and are preserved. Light Detection and Ranging (LiDAR)-derived digital terrain modelling supported by information from other sources is used to map landform units (terraces, palaeochannels, terrace 'islands' and edges, etc.) within a Geographic Information System (GIS) framework. The high horizontal and vertical resolution of LiDAR allows microtopography to be mapped and this is often indicative of sub-surface geomorphological structures. In conjunction with historic environment record (HER) derived data this allows the macro- and micro-topography, relative chronology, and likely archaeological resource of key landform units to be modelled more accurately than has been previously possible. This enables areas of different archaeological potential to be highlighted, thus enabling more tightly focused, evidence-based evaluation and mitigation strategies to be developed. Other approaches such as specialist geophysical survey and, where organic material is sparse, the use of optically stimulated luminescence (OSL) dating can also be integrated to great effect to test the chronostratigraphic models produced. The use of this new 'toolkit' has a particularly high potential for application within large-scale, mineral extraction developments in river valleys, supporting the delivery of knowledge-based and proportionate projects at both pre- and post-determination stages as recommended in the minerals practice guide. This article focuses on a recent ALSF supported research project in the Lower Severn Valley which has tested the effectiveness of elements of the 'toolkit' within this major river catchment. This is accompanied by a case study of an evaluation undertaken in the Lugg Valley, a tributary of the River Wye in Herefordshire. This employed many of these techniques and provides one of the first examples of a commercially driven project where the considerable benefits of this approach to both archaeological curators and developers have been realized. [ABSTRACT FROM AUTHOR]

Abstract: Archaeological applications of airborne lidar topographic data are now well established and documented. However, less well explored by archaeologists and palaeoenvironmentalists are the potential applications of lidar intensity data. Here we explore this potential to remotely determine the differential preservation potential of valley floor sediments, within a temperate, lowland environment, especially where preserved within palaeochannels. We compare airborne lidar intensity data with simultaneously collected terrestrial records of sediment organic content, moisture and stratigraphy. Results suggest that while a correlation exists between lidar intensity values and sediment properties, it is neither linear nor robustly predictable. Nevertheless it is suggested that examination of lidar intensity data serve a useful purpose when assessing valley floor alluvial sediments. [ABSTRACT FROM AUTHOR]

In January and March 2000 two tailings dam failures in Maramures¸ County, northwest Romania, resulted in the release of 200,000 m3 of contaminated water and 40,000 tonnes of tailings into tributaries of the Tisa River, a major tributary of the Danube. The high concentrations of cyanide and contaminant metals released by these dam failures resulted in pollution and fish deaths not only in Romania, but also downstream in the Tisa and Danube rivers within Hungary, Serbia and Bulgaria. Following these accidents, a research programme was initiated in northwest Romania to establish metal levels in rivers affected by the tailings dam failures and to compare these to metal values in river systems contaminated by historic mining and industrial activity. In July 2000, 65 surface water, 65 river sediment and 45 floodplain sediment samples were collected from trunk streams and principal tributaries of the Lapus¸/Somes¸ rivers (affected by the January 2000 spill) and the Vis¸eu/Tisa rivers (affected by the March 2000 Novat spill) down to the Hungarian and Ukrainian borders, respectively. Sample analyses for Pb, Zn Cu and Cd show that metal contamination in surface water and river sediment decreases rapidly downstream away from presently active mines and tailings ponds. Concentrations of heavy metals in water and sediment leaving Romania, and entering Hungary and the Ukraine, generally fall below EC imperative and Dutch intervention values, respectively. However, Zn, Cu and Cd concentrations in river sediments approach or exceed intervention values at the Romanian border. The results of this survey are compared with earlier surveys to ascertain the long-term fate and environmental significance of contaminant metals released by mine tailings dam failures in Maramures¸ County. [Copyright &y& Elsevier]

The Aznalco´llar tailings dam at Boliden Apirsa's Aznalco´llar/Los Frailes Ag–Cu–Pb–Zn mine 45 km west of Seville, Spain, was breached on 25 April 1998, flooding approximately 4600 hectares of land along the Rı´os Agrio and Guadiamar with approximately 5.5 million m3 of acidic water and 1.3×106 m3 of heavy metal-bearing tailings. Most of the deposited tailings and approximately 4.7×106 m3 of contaminated soils were removed to the Aznalco´llar open pit during clean-up work undertaken immediately after the spill until January 1999. Detailed geomorphological and geochemical surveys of the post-clean-up channel, floodplain and valley floor, and sediment and water sampling, were carried out in January and May 1999 at 6 reaches representative of the types of river channel and floodplain environments in the Rı´o Guadiamar catchment affected by the spill. The collected data show that the clean-up operations removed enough spill-deposited sediment to achieve pre-spill metal (Ag, As, Cd, Cu, Pb, Sb, Tl, Zn) concentrations in surface sediment. These concentrations, however, are still elevated above pre-mining concentrations, and emphasise that mining continues to contaminate the Agrio-Guadiamar river system. Dilution by relatively uncontaminated sediment appears to reduce metal concentrations downstream but increases in metal and As concentrations occur downstream, presumably as a result of factors such as sewage and agriculture. River water samples collected in May 1999 have significantly greater dissolved concentrations of metals and As than those from January 1999, probably due to greater sulphide oxidation from residual tailings with concomitant release of metals in the warmer early summer months. These concentrations are reduced downstream, probably by a combination of dilution and removal of metals by mineral precipitation. Single chemical extractions (de-ionised water, CaCl2 0.01 mol l−1, CH3COONH4 1 M, CH3COONa 1 M and ammonium oxalate 0.2 M) on alluvial samples from reaches 1 and 6, the tailings, pre-spill alluvium and marl have shown that the order of sediment-borne contaminant mobility is generally Zn>Cd>Cu>Pb>As. Pb and As are relatively immobile except possibly under reducing conditions. Much of the highly contaminated sediment remaining in the floodplain and channel still contains a large proportion of tailings-related sulphide minerals which are potentially reactive and may continue to release contaminants to the Agrio–Guadiamar river system. Our work emphasises the need for pre-mining geomorphological and geochemical data, and an assessment of potential contributions of contaminants to river systems from other, non-mining sources. [Copyright &y& Elsevier]