Monitoring and Mitigation Works in Unsaturated Archaeological Deposits

Monitoring of the archaeological deposits at the World Heritage Site Bryggen in Bergen has been ongoing since 2001. In latter years a large-scale project of mitigation works has been carried out, resulting in the creation of a water-management system aimed at raising groundwater-levels and increasing soil moisture content in areas with poor preservation conditions. Oxygen is a key parameter in the decay of archaeological material in the unsaturated zone, and the monitoring at Bryggen includes in situ monitoring of oxygen concentrations and comparison to soil moisture content, temperature, groundwater-level, precipitation and soil reactivity. This is used to document where and when decay takes place and to estimate “how wet is wet enough” in order to reduce the oxygen diffusion and the decay rate to an acceptable level. The results show that even small changes in the soil moisture can have a large impact on the oxygen dynamics in the ground.     

Take the Right Decision Everybody

Abstract

The archaeological deposits in medieval towns are among the most important and distinctive heritage monuments in Norway. At the same time they are among the more challenging phenomena confronting heritage management authorities, municipal planners, and property owners/developers alike, especially in relation to building and infrastructure projects. The modern settlement has developed on top of medieval and younger deposits which means that not only are they an irreplaceable depository of historical information, but they also form a significant part of the modern town’s physical foundation.

Since 2002 the Directorate for Cultural Heritage in Norway (Riksantikvaren) has been funding systematic monitoring of archaeological deposits of the World Heritage Site Bryggen in Bergen. The monitoring programme consists of several approaches: archaeological assessment of the deposits state of preservation, biochemical investigation of preservation conditions within the deposits, hydrogeological mapping of the water table, water flow, and other given parameters.

Continuous systematic monitoring by using testable, replicable methods and measures, data, and results acquire increased quality and validity. These in turn provide the cultural heritage management with a toolbox for making correct decisions and thereby allow the government’s preservation targets to be attained. But, most important, it guarantees the preservation of the ‘underground archives’ and at the same time allows the urban centres to develop.

This paper presents the knowledge developed through monitoring the Bryggen site as a basis for an official Norwegian standard covering archaeological, biochemical, and hydrogeological deposit investigations.     

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.     

Thirty Years of Monitoring in England — What Have We Learnt?

Abstract

Over the last thirty years, over sixty separate episodes of monitoring waterlogged archaeological sites have been carried out in England. This paper lists these projects, summarizes basic information about them, and reviews what we have learnt over these last thirty years. Recommendations are given to help improve future monitoring projects. In particular, it is suggested that more work is needed on assessing the state of preservation of a site before monitoring is considered; that a proper project design needs to be developed at the outset of the work; and that more thought should go into deciding why monitoring is needed for a given site, including identifying mitigation options that can be initiated if monitoring data suggest optimum conditions for survival are no longer being maintained.     

Monitoring of Shipwreck Sites

A three-year research project, The Monitoring of Shipwreck Sites (MoSS), was initiated in 2001 as a partnership between several European countries: Finland (project leader), Germany, Holland, United Kingdom, Denmark and Sweden. The aim was to establish a suitable programme for the monitoring, safeguarding and visualizing of shipwreck sites, based on the investigation of three wrecks located in the Baltic and North Seas. Phase I involved the monitoring process, with the investigation of physical, chemical and biological factors that will help to identify potential threats to buried and exposed archaeological material. Phases II and III considered safeguarding and visualizing of shipwreck sites.
© 2005 The Nautical Archaeology Society     

Salt Effects in Plastered and Unplastered Outdoors Brick Masonry: Quantitative Laser Monitoring of Surface Decay Evolution

In masonry materials, the superficial decay is a widespread problem. Aggressive environmental agents such as moisture and salts trigger the damage by propagating through the material capillary pores. Although several studies have been carried out on salt crystallization and their damaging effects, additional research effort is required to better investigate this phenomenon on real cases and real weathering conditions. To this purpose, testing and monitoring tools capable of following degradation process since the early beginning are necessary. Repeated visual inspections are commonly used to monitor the superficial decay, but this technique is subjective and thus not capable of providing any quantitative information. In this work, an experimental campaign, carried out in Bologna, Italy, is presented. A two-header brick wall, one main face unplastered and one plastered, was stored outdoors and exposed to weathering over two summers. Before the start of the second aging season, moisture and salt capillary rise was simulated by low-concentrated sodium chloride solution (0.1% -wt). The aim was to favor solution evaporation and salt crystallization and to provoke material damage. The degradation process was monitored based on a contactless, rapid and accurate image diagnostic technique. In particular, high-resolution laser scanning by triangulation technique was adopted. Three-dimensional data acquisition was repeated at the end of both seasons. The proposed procedure successfully extracted quantitative information approximately areas of material spalling and detachment even in the initial phases of decay.     

Monitoring and Management Options in the Preservation of Urban Waterlogged Deposits,Nantwich, UK

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.     

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 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.     

试论考古与遗址保护

一、考古遗址的价值功能(一)古代遗址的价值功能保存至今的古代遗址,其价值功能主要体现在如下三个方面。第一,历史载体。除了传世的古代文献之外,我们了解古代历史的惟一途径就是发掘古代遗址。任何一个古代遗址,都是人类     

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.     

现代中国环境考古研究模式的分析

本文将1987年以来的中国环境考古研究称为"现代中国环境考古研究",并将之归纳为"考古地理的环境考古研究模式"、"文化历史环境考古研究模式"和"资源环境考古研究模式"。本文对这三种研究模式的合理性进行了分析。接下来,从考古学的基本理论假设出发,指出环境考古学、文化历史考古学之间并没有严格的继承关系,中国环境考古研究的最大问题是核心概念的不匹配。最后,通过考察西方环境考古研究和考古学史,本文提出应该用文化适应,即"考古学中的文化"取代考古学文化而将之作为核心概念进行环境考古研究,让中国环境考古摆脱文化历史考古学概念体系的束缚。     

A Qualitative Approach for Assessment of the Burial Environment by Interpreting Soil Characteristics; A Necessity for Archaeological Monitoring

Abstract

Modern-day archaeological monitoring is often hampered by lack of money, lack of time, inadequate measuring equipment, and lack of insight in the conservation potential of a site.

Although in modern archaeological excavations soil characteristics are noted (colour, texture, groundwater level, and sometimes mineralogy), these characteristics are mainly used for the interpretation of a site. However, by looking to these characteristics from a conservational view eventually combined with the conservation status of the archaeological objects, much can be learned about the burial environment. This is essential for optimizing archaeological monitoring.

Degradation processes result from the change of reactive phases in the soil or the site. Reactive phases are soil components such as organic matter, sulfides, iron(hydr)oxides and carbonates (chalk, shells), and, if present, components in the ground or interstitial water such as hydrogen ions and sulphate. The presence of these phases can easily be established by the archaeologist or soil scientist in the field. We propose a simple field-based method for assessing degradation processes essential for in situ preservation and monitoring.     

潮湿环境下古象牙的现场提取与保护——以三星堆遗址三号坑出土象牙为例

2020年10月,三星堆遗址新发现祭祀坑正式启动考古发掘工作。随着发掘工作的推进,大量象牙相继出土。由于长期埋藏于潮湿的地下环境,象牙基本处于饱水状态,保存状况较差。为了使象牙保持相对稳定的状态,在考古发掘现场针对不同象牙的发掘情况,采用高分子绷带进行固形处理,然后整体提取回实验室清理。清理完成的象牙,经过保湿杀菌处理后存放至低温高湿专用库房。三星堆遗址三号祭祀坑出土象牙的成功提取与保护,表明医用高分子绷带具有超越石膏提取法的应用优势,对类似出土遗物的现场保护工作有一定的借鉴作用。     

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.     

Implementation of Sustainable Urban Drainage Systems to Preserve Cultural Heritage — Pilot Motte Montferland

The shallow subsurface in historic cities often contains extensive archaeological remains, also known as cultural deposits. Preservation conditions for naturally degradable archaeological remains are strongly dependent on the presence or absence of groundwater. One of the main goals at such heritage sites is to establish a stable hydrological environment. Green infrastructural solutions such as Sustainable Urban Drainage Systems (SUDS) can support preservation of cultural deposits. Several cases show that implementation of SUDS can be cost effective at preservation of cultural deposits. These include Motte of Montferland, City mound of Vlaardingen, Weiwerd in Delfzijl, and the Leidse Rijn area. In all cases, the amount of underground infrastructure is minimised to prevent damaging cultural layers. SUDS have been implemented to preserve cultural heritage. The first monitoring results and evaluation of the processes give valuable lessons learned, transnational knowledge exchange is an important element to bring the experiences across boundaries.     

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.     

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.     

Assessing Representation at Different Scales of Decision Making: Rethinking Local is Better

The nature and quality of representation in public participation is crucial to reaching acceptable environmental decisions that can be implemented. Ten case studies of natural resource management groups involved in agriculture in south western Australia were conducted at four spatial scales—state, regional, land conservation district (shire or county), and subcatchment. Qualitative analysis identified the desirable qualities of representatives, and then compared perceptions of current practice at the four scales against these ideals. Desirable qualities were being an active participant, competency (skills and knowledge), credibility, adopting the group identity and commitment, communicating outside the group, having established social networks, and an ability to function in multiple roles. Analysis across scales suggests that for groups at broader spatial scales of organizing, such as the state level, representation was closer to achieving the desired qualities than at other scales. This finding is contrary to much of the current rhetoric in natural resource management, and environmental management more generally, that "local is better." The article concludes with some thoughts as to why this is the case, suggesting that the success or otherwise of representation, and the public participation in which representatives are involved, is influenced not only by the scale of decision making but also by how representatives are selected and what they are expected to achieve.     

Laboratory Research on the Effects of Heavy Equipment Compaction on the in situ Preserved Archaeological Remains

Following the Malta Convention/Valletta Treaty the preferable way for the physical protection of archaeological sites is in situ preservation. When planning in situ preservation, in addition to other issues, it is also necessary to consider changes in physical environment and their impact on in situ preserved remains. This is especially important when human interaction takes place. Recently, an increase in construction on the top of archaeological sites has occurred, thus the effects of heavy equipment compaction need to be studied in more detail.

This paper presents research on the effects of the use of heavy equipment (e.g. rammers and rollers) compaction on archaeological remains. For the purpose of our research, laboratory testing has been performed. In a custom-made steel box, artificial archaeological sites were created using layers of sandy silt and gravel. A variety of archaeological and modern artefacts were placed in these created environments. Some of them were equipped with strain gauges for deformation recording. Through a series of tests a servo-hydraulic piston was used, which simulated the dynamic loading of the artificial sites. Humidity and temperature were recorded before, during, and after each test. Since layers and artefacts were three-dimensionally recorded before and after each test, compaction of layers and movements of artefacts could be studied. With attached strain gauges and visual inspection following each test, deformations and thus damage to artefacts during different stages of loadings was recorded.

The goals of our laboratory tests were the development of a new methodological approach to study the effects of heavy equipment compaction to the archaeological sites, getting an insight into the problems of such tests, and the estimation of the applicability of their results. With the presented results, our research has been a step towards better understanding the effects of heavy equipment compaction on archaeological remains and thus to the preservation of archaeological sites in situ.