The conservation and restoration of archaeological sites is the collaborative effort between archaeologists, conservators, and visitors to preserve an archaeological site, and if deemed appropriate, to restore it to its previous state. Considerations about aesthetic, historic, scientific, religious, symbolic, educational, economic, and ecological values all need to be assessed prior to deciding the methods of conservation or needs for restoration. The process of archaeology is essentially destructive, as excavation permanently changes the nature and context of the site and the associated information. Therefore, archaeologists and conservators have an ethical responsibility to care for and conserve the sites they put at risk.
Site lifecycle Archaeological sites go through many phases.
Creation of Site: The site is constructed and serves a function within the culture. Initial Deterioration: The site has fallen out of use or has been abandoned. Forces of nature, such as wind and water, may shift the site and cause instability. Dust and dirt may settle on top of the site. Animals and insects may settle into the site, feeding on and destroying organic materials. Identification: The site is identified by archaeologists or locals or other non-professionals. Excavation: The site is excavated by archaeologists and the findings are documented. Sites may be primarily explored by non-professionals. This may disturb the integrity of the site, prior to formal excavation. If this is the case, crucial pieces of cultural and archaeological evidence may be lost. Post-Excavation Deterioration: Once again exposed to the elements, sites are vulnerable to deterioration. Archaeologists and conservators should take steps to avoid this secondary deterioration by building shelters, such as roofing, and removing delicate organic materials. Ignorant Repair: Attempts are made to rebuild a site by non-professionals or professionals using inappropriate methods. This can result in further damage to the site. The use of incorrect materials or a lack of understanding of the prior state of the site can lead to deterioration. Correct Conservation: Trained professionals assess the best method of conservation through thorough analysis, in order to preserve the site. Decisions during this phase should be made with the consideration of the cultural and historical value of the site prior to conservation intervention. Reburial: In the instance that leaving a site exposed may cause it further harm, a decision is made to rebury the site.
These phases may be repeated and may occur in a different order.
Agents of deterioration
Weathering Weathering is the source of most of the deterioration of archaeological sites. Wind, rain, freeze-thaw, and evaporation are extremely common and can cause erosion. Natural disasters, such as floods, fires, earthquakes, and volcanic eruptions, can cause the complete destruction of a site. The most effective way to protect archaeological sites from these larger events is to formulate a risk management plan. Archaeologists and conservators should assess threats to the site and determine material susceptibility.
Climate change Climate projections also show that changes in rainfall (intensity and frequency), increases in temperature and frequency of heatwaves, rising sea levels and groundwater fluctuations, warmer seas and ocean acidification will also result in changes to flora and fauna, ground conditions (on and below the surface) will affect archaeological deposits and structures. Human responses to the climate crisis also impact archaeological sites.
Development
Modern development poses a great risk to archaeological sites. Vibrations from construction can cause instability and cracking of structures. An example of the effects of modern development can be found at an ancient Puebloan site in Arizona, that dates to AD 900–1350. It was damaged by construction activities while putting in a new road. After the damage was assessed, it was determined that the site was not eligible for the National Register of Historic Places. This determination was made due to construction activities destroying any information that was important in prehistory or history that was remaining at the site.
While development cannot be discontinued simply to protect archaeological sites, having a basic understanding of what might be impacted before development takes place could help protect sites and at least the information they can provide. The Arizona Antiquities Act of 1960 is an example of some ways in which archaeological sites can be protected.
Vandalism Vandalism is also a prominent force of damage to archaeological sites. A range of actions can be considered, including graffiti, carving, deconstruction, and burning. These can be intentional or unintentional. Intentional vandalism occurs when visitors know that there is an archaeological site and still choose to deface it in some way. Unintentional vandalism happens when the visitor vandalizes while not realizing they are at an archaeological site, such as accidents.
To protect an archaeological site from vandalism requires a combination of techniques. The most effective course of action is educating the public. This does not just entail explaining the harms of vandalism—but to educate them on the importance of these sites, and what could be lost if it is vandalized. Signage should be posted at the site to alert visitors. Another possible measure to prevent vandalism is the addition of barriers, patrols, or even full-time observation and security.
Looting Looting is the theft of artifacts from archaeological sites. Looting is often the main source of artifacts that enter into the antiquities market, in which objects are sold domestically or exported internationally. In the United States, there are laws for the protection of archaeological sites that contain penalties for those who choose to loot or cause disturbances. The act of looting serves as a disservice to both stolen objects and the sites themselves, as objects lose their historical context and sites lose record of even having that object in the first place. Archaeologist Arthur G. Miller states, "our very strong concern is because the looting of archaeological remains destroys those sites without any record whatsoever, let alone any record of the context from which artifacts are wrenched. It is as if a few particularly attractive pages were ripped from the books of a library, and the remainder burnt. In a word, the context is destroyed without record, so that most of the information vital to the fullest study and reconstruction of the past is irremediably lost to the world."
War
Throughout history, war has been the source of destruction of many archaeological and historical sites. During World War II, the Nazi's destroyed many buildings during the planned destruction of Warsaw, including several palaces and other buildings dating back to before the 13th century. The prevention of destruction due to war is almost impossible without large-scale strategies. Efforts by the Monuments Men during World War II is an example of an organized plan to protect the art and history of Europe from destruction at the hands of the Nazis. The Monuments Men played a significant role in attempts to repatriate art stolen during World War II. The Rape of Europa is a book, turned documentary that explains the Nazi's systematic theft and destruction of art during the war, and the implications for international museums and art collectors that followed.
In recent times, the Taliban destroyed a sacred Buddha statue in Afghanistan.
Personnel Archaeologists The goal of archaeologists in the conservation of excavation sites is "to preserve the physical remains of our past and to employ them in perpetuating our historical heritage". This goal can be reached by ensuring that there is thorough documentation of archaeological sites, where details of the physical characteristics of the site itself and the excavations it has endured are written down. In the case that a site is destroyed, thorough documentation can preserve the memory of how it once existed. Archeologists are turning to other methods to preserve sites and use excavation techniques that impact sites as little as possible and save their natural features. Partial excavations are currently being conducted in place of full excavations to answer research questions without causing unnecessary deterioration to sites. A previous technique involved reconstructed walls and other site features to resemble their original structure. However, this method has mostly fallen out of use, and archaeologists and conservators are now focused on preserving the site in its present state
Conservators Conservators are the other leading voices for the advocacy and of archaeological site conservation. It is these specialists that are needed to formulate the most sustainable and effective plan for the successful preservation of sites and they do so using the help of the expertise of the archeologists that know the sites up close and personally from their own excavations as well as their own experience and knowledge. Martha Demas (2004) has created an outline that conservators can rely on to create the most effective plan:
Identification and description
Aims: What are the aims and expectations of the planning process? Important to establish a common ground between stakeholders and the lead organizations Stakeholders: Who should be involved in the planning process? Can include: "Government agencies, groups with ancestral relationships to sites, local community members, tourist groups." Documentation and Description: What is known about the site and what needs to be understood? Demas reminds us that: "The mistake that can be made with this activity is to see it simply as compiling information for its own sake. Rather, the activity needs to be seen as strategic: the results will inform the assessments and contribute to establishing policies for research and excavation, interpretation, conservation, and use of the site."
Assessment and Analysis
Cultural Significance/Values: Why is the site important or valued and by whom is it valued? Conservation is a value-driven practice: identify diverse values that make a site worth preserving. Usually "historical or artistic, research, natural, civil/social, spiritual/religious, symbolic/identity, or economic values." Physical Condition: What is the condition of the site or structure; what are the threats? Condition Surveys are conducted to document and assess the physical state of an archaeological site. Documentation is crucial to a successful conservation effort. Management Context: What are the current constraints and opportunities that affect the conservation and management of the site? A Management Assessment is conducted to assess any other matter that may affect the conservation of a site other than its physical condition. This may include: "legal/legislative context, financial base, power base, infrastructure, regional/local development context, visitor numbers/profile/and impact, structure of organization, staff resources and expertise, monitoring/maintenance systems, or research assessment."
Response
Establish Purpose and Policies: For what purpose is the site being conserved and managed? How are the values of the site going to be preserved? Link the assessment of values, condition, and management context of sites through policies. Demas recommends that it is useful to develop policies in "programmatic" or "activity" areas such as "appropriate use, conservation intervention, visitation and interpretation, research and excavation, and maintenance and monitoring." Set Objectives: What will be done to translate policies into actions? "Objectives" are considered clear targets that have measurable results. Difference between "objectives" and "strategies" needs to be established here.