In Situ Preservation and Monitoring of the James Matthews Shipwreck Site

Abstract

Over the past few decades, the archaeological community has been moving away from the more traditional methods of excavation and recovery of underwater cultural heritage towards a less intrusive management approach, essentially involving the preservation of sites in situ. This trend has been politically galvanized in Article 2, point 5 of the Convention on the Protection of the Underwater Cultural Heritage (), which states that ‘The preservation in-situ of underwater cultural heritage shall be considered as the ?rst option before allowing or engaging in any activities directed at this heritage’. Over the years, a number of different remediation strategies have been utilized in order to protect underwater cultural heritage sites in situ, and most of the techniques or combinations thereof involve reburial of sites. Reburial may be an appropriate means of stabilizing and decreasing the deterioration rate of a site, however, there needs to be a holistic approach to the study of the environment, before and after reburial, to gain a full understanding of the changes that are occurring on the site and determine the effectiveness of the technique.

In early 2000, the James Matthews, a copper-sheathed, wooden-hulled vessel wrecked in 1841 south of Fremantle, Western Australia, was identi?ed as being under considerable threat from increased site exposure due to a combination of natural near-shore sedimentary processes and industrial activity in the immediate area. An extensive on-site conservation survey was carried out to establish the state of preservation of the wreck and provide information regarding the physico-chemical and biological nature of the environment prior to the implementation of any mitigation strategy. In 2003 it was con?rmed that further exposure of the site was occurring and devising a management plan was of paramount importance.

Since this time a number of different reburial techniques have been trialled on the site and these include sand bags of differing material composition, polymeric shade cloth, arti?cial sea grass mats made from polyvinyl chloride bunting, and the use of interlocking medium density polyethylene ‘crash barrier’ units in a cofferdam arrangement to con?ne deposited sand. The geological, physico-chemical, and microbiological changes in the burial environments have been monitored over this time. Furthermore, the broader scale, near-shore sedimentary processes affecting the site are being assessed in order to establish the reasons behind the continuing sediment loss. In situ preservation of the iron ?ttings by cathodic protection has also been included in these ?eld trials. In this paper the results from these experiments will be summarized. This information will be used to ?nalize the design of the full-scale in situ preservation strategy for the site and assist in establishing a post-reburial monitoring programme that will measure the success of the adopted remediation technique.     

In Situ Preservation of Ancient Floor Mosaics in Turkey

Abstract

As stated in the Burra Charter (1979) ‘A building or work should remain in its historical location. The moving of all or part of a building or work is unacceptable unless it is the sole means of ensuring its survival’. This statement has been neglected many times during rescue excavations in Turkey (e.g. Zeugma), whereas the destruction of ancient floor mosaics caused by lifting, especially when carried out by incompetent or inexperienced personnel at systematic archaeological excavations, has steered the authorities desire to preserve them in situ. However, due to the lack of conservation professionals and insufficient resources for conservation, it becomes a difficult issue to provide an effective preservation scheme for archaeological excavations. This paper aims to discuss this important issue in terms of the national legislation, preventative and interventive conservation approaches at various sites, exhibition and maintenance of mosaics, as well as the training of conservation technicians in Turkey.     

In Situ Preservation of Wetland Heritage: Hydrological and Chemical Change in the Burial Environment of the Somerset Levels,UK

Abstract

In situ preservation is a core strategy for the conservation and management of waterlogged remains at wetland sites. Inorganic and organic remains can, however, quickly become degraded, or lost entirely, as a result of chemical or hydrological changes. Monitoring is therefore crucial in identifying baseline data for a site, the extent of spatial and or temporal variability, and in evaluating the potential impacts of these variables on current and future in situ preservation potential.

Since August 2009, monthly monitoring has taken place at the internationally important Iron Age site of Glastonbury Lake Village in the Somerset Levels, UK. A spatial, stratigraphic, and analytical approach to the analysis of sediment horizons and monitoring of groundwater chemistry, redox potential, water table depth and soil moisture (using TDR) was used to characterize the site.

Significant spatial and temporal variability has been identified, with results from water-table monitoring and some initial chemical analysis from Glastonbury presented here. It appears that during dry periods parts of this site are at risk from desiccation. Analysis of the chemical data, in addition to integrating the results from the other parameters, is ongoing, with the aim of clarifying the risk to the entire site.     

Quantification and Visualization of In Situ Degradation at the World Heritage Site Bryggen in Bergen,Norway

Abstract

Environmental monitoring at the World Heritage Site of Bryggen in Bergen, Norway, has shown damaging settling rates caused by degradation of underlying archaeological deposits. Measurements of piezometric head, oxygen, and soil moisture content, as well as chemical analyses of water and soil samples are key elements of the environmental monitoring.

Groundwater monitoring and geochemical analyses reveal a complex and dynamic flow through the natural and anthropogenic stratigraphy. The preservation conditions within the organic archaeological deposits are strongly correlated with oxygen and soil moisture content, that are controlled by the groundwater flow conditions at the site. To quantify decay rates, it is thus essential to understand the wider hydrogeological context of the site. This paper presents recent advancements in quantifying decay rates in the saturated zone at Bryggen. The paper also shows that 3D geo-archaeological modelling can contribute to preservation management by visually combining results of geological, archaeological, geochemical, and hydrological investigations. This opens up for improved multidisciplinary understanding of preservation potential, thereby contributing to an improved protection of archaeological deposits in situ.     

In Situ Preservation of Marine Archaeological Remains Based on Geodynamic Conditions,Raja Ampat,Indonesia

Marine archaeological remains in the Raja Ampat waters play an important role in the development of maritime history and culture in Indonesia. Three World War II American P47-Razorback planes are preserved here and the site has been developed for tourists and a research laboratory for scientists. However, the site is tectonically active which threatens the wrecks.     

Combining New Awareness and Public Support for Archaeology with In Situ Preservation of an Archaeological Monument

Preserving archaeological remains in situ is one of the main objectives of the Valletta Treaty, which was signed by the Dutch government in 1992. Subsequently, preservation in situ has become one of the pillars of archaeological heritage management in the Netherlands. Another objective of the Treaty is the promotion of heritage education and raising of public awareness for the protection and investigation of archaeological heritage. Until recently, this goal has received too little attention. The design and building of an underground visitor centre, DOMunder, raised an important question: How can we transform an archaeological monument into an asset for the community and at the same time ensure long-lasting preservation? Not many parallels exist, as most archaeological sites in urban environments are seen as a burden for development. Sites are generally either excavated or left in situ; in both cases the archaeology remains invisible and inaccessible to the public. In the case of DOMunder, the location in a wet sedimentary environment provided even more challenges. This paper focuses on a few of the many questions and problems that were raised before and during the building process and the (preliminary) answers and solutions.     

The Australian Historic Shipwreck Preservation Project: In situ Preservation and Long-Term Monitoring of the Clarence (1850) and James Matthews (1841) Shipwreck Sites

Increasingly, archaeologists are opting for on-site examination, reinterment, and in situ preservation of underwater cultural heritage sites as the first option in the management of sites at risk, as opposed to the more traditional excavation, recovery, conservation, and display/storage methods. This decision will inevitably be based on significance assessment, degree of perceived risk, and resourcing issues. However, long-term monitoring must become an integral part of these management programmes in order to quantitatively evaluate the effectiveness of the in situ preservation techniques employed. In 2012 the Australian Historic Shipwreck Preservation Project (AHSPP) was awarded a large Australian Research Council (ARC) Linkage Grant, enabling ten partner organizations and three Australian universities to collaborate in one of the largest multi-organizational maritime archaeology projects to be undertaken in Australia to date. One of the major aims of the project is to develop a protocol for the excavation, detailed recording and reburial of significant shipwrecks under threat, fostering a strategic national approach for the management of underwater cultural heritage (UCH) sites at risk. Two historically significant shipwreck sites that are considered under threat were chosen for this longitudinal comparative study — the Clarence (1850) located in Port Phillip Bay, Victoria; and the James Matthews (1841) which lies in Cockburn Sound, Western Australia. Both sites have been preserved in situ using two very different but innovative remediation strategies. More importantly, long-term monitoring programmes have been implemented on both sites, which will characterize changes in the reburial environment and the effect on the reinterred materials. In this way, the efficacy of both in situ preservation techniques will be systematically tested, providing a comparative analysis of practical protocols for the long-term protection and management of underwater cultural heritage.     

The Danish 17th-Century Man-of-War Stora Sofia: Documentation and in situ Preservation

In 2002 Bohusläns museum, Sweden, conducted archaeological recording of the Danish man-of-war Stora Sofia , which foundered in 1645 just outside Gothenburg on the Swedish west coast. This was followed by an in situ preservation project involving a protective covering and a monitoring protocol. After three years of intensive monitoring the results are satisfying. In particular, the wooden samples show obvious differences in deterioration between the exposed outside environment and the newly-protected site. As well as preserving the remains of Stora Sofia , the project also represents the beginning of a more active regional strategy in marine in situ preservation.
© 2009 The Author     

Complications and Effectiveness of In Situ Preservation Methods for Underwater Cultural Heritage Sites

Abstract

Underwater Cultural Heritage (UCH) as an outstanding division of the cultural heritage of humanity appears to be crucial and complicated when more general issues regarding preservation and conservation are raised. The essence of in situ preservation should be equally discussable for any kind of archaeological remains; on land or underwater.

There is a long history of different methods and concepts of intervention in a variety of sub-aquatic archaeological sites; from shipwrecks to submerged settlements. This paper will present an introduction to different techniques and theories of preservation and conservation of underwater cultural and archaeological sites since this kind of heritage has scientifically been explored and studied. A range of different preservation methodologies, from total or partial transference inland, to preservation underwater, will be compared; the advantages and disadvantages of each option will be highlighted. Different examples of international best practices will be illustrated. Different types of in situ conservation/protection will be explained and categorized. Furthermore, there will be a focus on the UNESCO Convention of 2001 on Conservation and Preservation of UCH, where the in situ conservation option has been recommended.

Moreover, the technical issue for preservation of UCH sites, either in situ or after displacement, will be explained. The implication of relocation for different sorts of sites and materials will be argued; for example, cases where some sites, such as shipwrecks, would more easily be displaced compared with submerged settlements, villages, or ports.

Finally, by stressing that the state of ‘being underwater’ makes many sites qualified to be regarded as UCH, the in situ preservation approach will prevail that this state is maintained.     

Long-Term Preservation of Dendroarchaeological Specimens and In Situ Preservation: Problems and Practical Solutions

Abstract

Dendrochronology offers a unique opportunity to address archaeological questions with minimal invasiveness. Often, archaeological tree-ring sampling, and occasionally analysis itself, can be performed while the larger structure or object remains in situ. In comparison to the costs and benefits of excavation (complete or partial) and a growing international call for in situ preservation, dendrochronology provides an effective compromise for the interpretation of wooden material culture.

The current number of archaeological tree-ring specimens worldwide probably exceeds 2,000,000. These specimens have been obtained from thousands of historic buildings, shipwrecks, and other sites and artefacts. These specimens are housed by a variety of public and private entities: museums, universities, governments, private corporations, and individuals. Despite their importance as vouchers for archaeological dates and great potential for future use and new applications, generally little attention has been paid to the long-term curation of tree-ring specimens. This paper identifies some pressing curation problems and suggests that the value and nature of dendroarchaeological research is compatible with international calls for in situ preservation. Some practical suggestions, provided here, could drastically improve the long-term curation of dendroarchaeological specimens, further demonstrating the methodology as a viable and valuable partner to in situ preservation.     

Laboratory Experiments as Support for Development of In Situ Conservation Methods

Abstract

Within the EU-Project BACPOLES (EVK4-CT-2001-00043) bacterial wood degradation could be simulated in laboratory experiments to investigate the living conditions of the up to now unknown bacteria consortia, named erosion bacteria (EB), which cause considerable decay on waterlogged archaeological wood. In these Microcosm (MC) experiments the role of oxygen and chemical composition of the sediment were investigated. Therefore, the microcosms were subjected to different gassing treatments and the free dissolved oxygen was measured in different depths of the microcosms by special oxygen sensors (optodes). In further experiments the chemical composition of the sediment was verified to investigate the influence of different nutrient concentrations to the degradation process by EB.

From the findings it can be concluded that bacterial wood decay can proceed without free oxygen present but that it is more intense if oxygen is available. A water flow like streams in the sea, simulated by vertical water circulation, seems to stimulate the degradation activity and the degradation of wood by EB seems to be a result of low nutrient levels in the surrounding area.     

Studying the Cannons of Punta Santa Anna,Spain: In Situ Conservation,Promoting Public Access,and Monitoring Iron Corrosion

The 2001 UNESCO convention for the Protection of Underwater Cultural Heritage (UCH) encourages and supports projects that would make accessible to the general public underwater cultural sites. Since 2010 the Catalonian Federation of the World Underwater Federation (FECDAS), have been developing outreach activities with the objective of promoting the protection of the UCH among recreational scuba divers. The purpose of this paper is to introduce one such project, the Punta Santa Anna in Blanes, Spain. This project has three objectives: the promotion of UCH to the general public, the in situ protection of this underwater archaeological site, and a case study on iron corrosion processes. FECDAS/CMAS will create an underwater archaeological park where recreational scuba divers will be able to visit some purposely selected archaeological iron cannons. To expose UCH to the general public will potentially affect the integrity of these artefacts. This risks potential damage and so, with the objective of minimizing potential threats, a series of protective measures and a systematic monitoring programme have been planned. The programme is designed to study the relationship between the underwater environment and the artefacts. The aim is to acquire a better understanding of the corrosion processes of iron objects present in marine underwater sites.     

PARIS London: One Hundred and Fifty Years of Site Preservation

Abstract

This paper outlines the history of preservation in situ as practised in London over the last hundred and fifty years. It touches upon the early development of the City of London and the destruction of significant remains, which gradually lead to a heightening of sensitivities and public concern for preservation, particularly of built fabric such as the Roman defences. The role of cases such as the Walbrook Mithraeum and Rose Theatre are discussed, both influential in changing the relationship between development and archaeology. The paper concludes by noting how much we have learnt from past mistakes, but notes that more can be done to make these sites more accessible.     

Founding of a Monumentenwacht for Archaeological Heritage in Flanders (Belgium)

Abstract

In August 2009, Monumentenwacht Vlaanderen set out to develop a new service and monitoring system for archaeological heritage in Flanders. Such an initiative takes time, for it needs to be done thoroughly, and there are many questions that need to be addressed. The answers can be found partly in examples in other countries, but must also be evolved in practice within the Flemish context, where a policy on in situ preservation of archaeological heritage is still in its infancy. This paper explains how this new service has been set up.     

Effects of a New Hydrological Barrier on the Temperatures in the Organic Archaeological Remains at Bryggen in Bergen,Norway

The World Heritage Site of Bryggen in Bergen, Norway, has experienced significant degradation of archaeological deposits as a consequence of changes in the soil water and groundwater balance after urban redevelopment adjacent to the heritage site. Additionally, groundwater temperatures below the heritage site were found to be significantly higher closer to the redeveloped area. One of the main mitigation measures taken to reduce the degradation of the archaeology has been the construction of a hydrological barrier along the sheet piling that divides the redeveloped area and the historic site. A shallow subsurface infiltration system was designed to achieve groundwater levels and flow conditions that are optimal for the preservation of archaeological remains directly along the sheet pile, while reducing drainage and subsidence also further upstream. Monitoring of groundwater level and temperatures after implementation of the hydrological barrier shows that groundwater levels and flow conditions have improved with respect to optimal preservation conditions, and groundwater temperatures have generally been reduced by up to 2 °C.     

The Rose Theatre: Twenty Years of Continuous Monitoring,Lessons, and Legacy

Abstract

The discovery of the Rose Theatre in 1989 led to the implementation of new planning guidance focused on the presumption that the preferred response to development impacting on archaeological sites would be mitigation and preservation in situ. There was little understanding of what the impact of mitigation would be on the quality of the buried evidence and the Rose Theatre site was the first to be scientifically monitored. As a direct result research was implemented and the PARIS series of conferences were initiated.     

In Situ Characterization of Rammed Earth Wall Renders

The Algarve region in southern Portugal has one of the most significant rammed earth construction legacies in the country. This construction method is characterized by its high susceptibility to water damage and external renderings are essential to the longevity of these constructions. This study collects and organizes data that provides the basis for the conservation and repair of renderings. Five earth buildings from western Algarve were selected to represent this heritage and its diversity of composition and susceptibility to water damage. Some of their commonest anomalies result from the interaction between the earth substrate and the traditional external renderings, given their distinct characteristics and behavior. The selected sample is described and the mechanical strength of the rammed earth walls and their renderings are evaluated through in situ tests. Samples of the external renderings and earth substrate of the five buildings comprising the sample were also collected and characterized in the laboratory. The characteristics of these two materials and their behavior as an assembly were analyzed. The results of the in situ and laboratory tests are compared and the viability of using a method based on in situ tests for the wider characterization of the type of construction under analysis evaluated.     

Relax,Don’t Do It: A Future for Archaeological Monitoring

Preservation in situ and the monitoring of archaeological sites have become important themes since the acceptance and implementation of the Valletta Treaty. In the last few decades, our knowledge of degradation processes has increased manyfold, and a range of techniques have been tested and applied for use in both assessment and monitoring. Despite these successes, all is not well. First, we have little notion of the speed of the decay processes involved. This makes it difficult to distinguish between acute and protracted degradation. Apart from that, many assessments and subsequent monitoring projects rely (too?) heavily on complex and costly specialist technology. For any future preservation — in situ — projects low-tech observations together with best estimates of decay rates and archaeological site information should be combined to make an accurate assessment of the effects of decay on the archaeological record. Monitoring for preservation purposes is only appropriate if (1) decay processes occur within a relevant and measurable time scale, and (2) if mitigating actions can be taken or preservation ex situ can be performed (i.e. a rescue excavation) if significant degradation takes place.     

Lowland Floodplain Responses to Extreme Flood Events: Long-Term Studies and Short-Term Microbial Community Response to Water Environment Impacts

Abstract

Targeted studies of waterlogged burial environments allow researchers to gain holistic insights into the physico-chemical and biological condition of wetlands that have the potential to contain organic remains of both anthropogenic and biogenic origin. Recent research has shown that microbial community diversity and functioning are intimately linked to physical and chemical parameters, such that environmental perturbations may have the potential to enhance the effectiveness of microbial communities in the degradation process. Our studies have shown that, as a consequence of the 2007 floods which impacted upon many British lowland rivers, a rapid microbial response to environmental perturbations can be demonstrated within the wetland deposits being monitored. As such, a quantification of the latent functionality of micro-organisms in a soil profile may be of fundamental importance for our understanding of potential in situ degradation processes; and, as a consequence, the likelihood for the biodegradation of sensitive archaeo-organic remains; a factor which is of primary importance for both ongoing and future mitigation strategies, and attempts at managing the cultural resource of wetlands.

This paper will present a consideration of the effectiveness of a long-term research project in a lowland wetland at Newington, Nottinghamshire, England, studied between 2004 and 2008; and evaluate the efficacy of this study in relation to the significant impacts that occurred as a result of the severe floods in 2007. We conclude that the data generated after the floods necessitated a total re-evaluation of the first approximately two years of environmental monitoring, and that the impacts throughout the sediment profile continued for some time after the initial flood event. These observations potentially have far-reaching implications for future in situ monitoring as disruptions to weather patterns influence the various environmental impacts on the wetland resource.     

Research and Monitoring on Conservation State and Preservation Conditions in Unsaturated Archaeological Deposits of a Medieval Farm Mound in Troms and a Late Stone Age Midden in Finnmark,Northern Norway

This paper presents archaeological observations and results of palaeoecological and geo-chemical analyses of archaeological deposits from two rural sites in northernmost Norway. These are combined with climate data and the first period of continuous monitoring of soil temperature, moisture, and redox potential in sections. This data constitutes the basic research material for evaluations of conservation state and preservation conditions. The data has been collected in collaboration with the partners of a cross-disciplinary project: ‘Archaeological Deposits in a Changing Climate. In situ Preservation of Farm Mounds in Northern Norway’ funded by the Norwegian Council for Research (http://www.niku.no/en/archaeology/environmental_monitoring/archaeological_deposits_in_a_changing_climate_in_situ_preservation_of_farm_mounds/). This is an important Norwegian research initiative on monitoring of rural archaeological deposits, and the results have consequences for heritage management of a large number of sites from all periods. Palaeoecological analyses and redox measurements have revealed ongoing decay that might not otherwise have been detected. Decay studies indicate that both site types may be at risk with the predicted climate change. Some mitigating acts are suggested.