Preventive archaeology, the key for a sustainable and integrated planning of electricity infrastructure

Wherever you dig in Italy, you find items that bring centuries of history back to life. A country with countless layers, scattered with thousands of archaeological sites, most of which still completely unknown. And, if there is one thing Italians can brag about, it is definitely the cultural heritage that they have been lucky enough to inherit from the past. An invaluable heritage made up of numerous Unesco sites (58) and over 2000 known archaeological sites, the safeguarding of which is included in the founding principles of the Italian Constitution.

Remains of Roman roads, residential and/or production buildings, ancient hydraulic systems, necropoli filled with wealthy ceramic and metallic goods, monumental tombs and much more, are just some of the items found during the excavations carried out for public works, also by Terna, that have enriched our historic knowledge and which, through valorisation projects shared with the competent Superintendencies, will contribute to improve the cultural and tourist offer of local territories.

But how to combine the need to protect and preserve such a widespread heritage with the just as important need to develop and upgrade the country’s infrastructure? The answer lies in the so-called “preventive archaeology”, i.e. the assessment of the archaeological risk of projects to avoid site closures while at the same diminishing their construction risk, thus guaranteeing the safeguarding of the national archaeological heritage. To obtain this result, a strong synergy between all parties involved is essential: clients, Superintendencies and professionals (e.g. archaeologists).

Terna, the national electricity grid operator, director and enabler of the ecological transition, has the task of maintaining a high service quality standard of electricity transmission high and of contributing to steering the Country towards a new model of decarbonised development based on renewable sources and respectful of the environment and the vast cultural, historic and archaeological heritage. Within this scenario, the company has set up an Archaeological Unit made up of various archaeologists that can directly follow all the phases envisaged by the preliminary survey for sites of archaeological interest during the planning phase with a dual objective: to avoid extended times and, therefore, costs following the finding of an archaeological item and to safeguard the findings until they are returned to the territory for their valorisation. This is not simple and requires high professionalism: Terna was one among the first companies in Italy, and is still one of the few, to create a team dedicated to preventive archaeology.

Archaeology thus becomes an active planning tool that helps guide planning as well as a shared opportunity for Terna and the territory to enhance the findings. There is a whole set of laws and regulations that discipline this sector. Culture and its assets, including archaeological ones, are based on art. 9 of the Italian Constitution: «The Republic shall promote the development of culture and of scientific and technical research. It shall safeguard natural beauty and the historical and artistic heritage of the Nation».

Starting from this, the safeguarding of the historic and artistic heritage has been set out in detail in a series of more specific regulations, including in particular the "Codice dei Beni Culturali e del Paesaggio" (Legislative Decree 42/2004) that regulates the protection of the Cultural and Landscape Heritage down to the "Nuovo Codice dei contratti pubblici" (Legislative Decree 36/2023) which instead regulates their application when it comes to public interventions and interventions of public utility. The topic is therefore addressed both in the regulations aimed at safeguarding the cultural heritage as well is in those that guarantee a proper use of public funds.

But how does preventive archaeology work? The procedure to verify archaeological interest includes various phases, the outcome of which integrates the feasibility planning of the infrastructure. Everything starts with the preliminary analysis, during which the contracting party informs the relevant archaeological Superintendency of the intention of carrying out work in a specific area. This is followed by the assessment of whether the preliminary survey can be carried out to assess the archaeological risk of a specific project, to understand whether there is an actual archaeological interest for the areas identified for intervention and if therefore there is a need to continue with an in-depth analysis.

During these preliminary phases, it is essential to collect all the historical and archaeological information that can be gathered from the data in the archives and bibliography, the cartographic analysis, place names and photographic interpretations (the analysis of an area by studying aerial photos, even historic ones) and from territory reconnaissance. But there is more, as precious information can also be obtained from talking to competent Superintendency officials, as they know the territory of interest more than anyone. This will enable archaeologists to collect essential data to assess the possibility of intercepting archaeological stratifications and therefore to establish the archaeological risk of the infrastructure and modify its planning to reduce such risks.

Based on the strategic importance of the infrastructure or of the territorial and archaeological context that surrounds it, Terna, in accordance with the different structures involved - including the archaeological unit - often chooses to independently anticipate all those specific site analyses that would normally be envisaged after this first phase, in particular for those infrastructures that represent “strategic hubs” of the future national electricity system (e.g. electrical substations). The process starts with the drafting of the Document for the Assessment of Archaeological Risk (the former preliminary archaeological report), which is transmitted to the Superintendency, which will then in turn express its opinion on the authorization of the infrastructure during the Service Conference and will assess the need for further archaeological surveys.

If, from the assessment reported in the document, the archaeological interest of the areas affected by the infrastructure is not that evident and the archaeological risk of the project is substantially “low”, the verification procedure is not initiated and the superintendent can anyway require “archaeological assistance during the course of work”, through which the archaeologist monitors the excavation work envisaged by the project and is ready to intervene in case of findings. However, if the assessment made as part of the document reports a “medium or high” archaeological risk, the Superintendency may request to verify such interest via a procedure to assess the archaeological interest, prescribing non-invasive/indirect surveys (geophysical prospects that do not involve “digging”) and/or invasive/direct surveys (such as drilling, preliminary assays and extensive digging). The purpose of such surveys is to ascertain the presence of archaeological deposits so as to assess their compatibility with the infrastructure part of the project.

Non-invasive methods (magnetometry, georadar, resistance or geo-electric) conducted with specific tools are quite rapid and return a sort of “radiography” of the land involved with the relevant “clinical picture”, i.e. the possibility of whether ancient elements or structures can be found in the land. Direct surveys such as essays and extended digging, although lengthier and more complex, are the only ones that definitely clarify the context.

Such a procedure can be concluded in 3 different ways depending on the outcome of the excavation work:

• Negative outcome. Project compatible. The excavation work has not detected any archaeological elements or the excavation itself has solved the safeguarding need
• Conditioned positive outcome. Project compatible with prescriptions. The archaeological elements emerged do not preclude the feasibility of the project. They can be re-buried, removed and even relocated
• Positive outcome. Project not compatible. The archaeological context determines the need to change the project, as its safeguarding can only be guaranteed by maintaining the site intact.

This means that the archaeological contexts identified will have to be excavated and documented to verify their extension, type and chronology so as to be removed or relocated (if possible) elsewhere to guarantee their protection and confirm the compatibility with the infrastructure to be built. Only in case of incompatibility between the findings and the infrastructure planned, will it be necessary to modify the initial project so as to finalize it while at the same time protect the archaeological heritage found.

It is worth stressing the importance and delicacy of the excavation phase, as excavations are by definition "not repeatable" and are therefore a destructive survey method. That is why they must be conducted with extreme attention and accuracy, in a timely manner and according to the indications laid out by the Superintendency. The safeguarding, in case of positivity, does not end with the discovery of the finding. It also includes the cataloguing, preservation with its restoration, and the study of the site identified also for the purpose of its valorisation and display in exhibitions, publications, dissemination projects and the creation of museums of the utmost value for the history and re-evaluation of the territory.

Although the perception is that such procedures slow down and hinder the infrastructural development of Italy, their real objective is actually the opposite: i.e. to guarantee modernisation by reducing the archaeological risk of projects, and make it compatible with the safeguarding of the country’s heritage, identity and historic inheritance, in particular by investing in their valorisation. As it is aware of the risks (slowdowns or stoppages of construction sites with inevitable higher costs and longer completion times), Terna has chosen to equip itself with full-time staff, setting up a dedicated unit whose task is to mediate between the needs of the project to be completed and those of the Superintendency as well as, most of all, to anticipate the considerations on archaeological risks as much as possible to “steer” the new projects, seeing as forecasting and anticipating the encounter with a finding is the best way to take care of it. And, while it is true that history is set in stone, it is also true that only those who know history will know how to interpret and manage it.