Reply by Instituto Portugues de Arqueologia to CAR-ICOMOS Alqueva Report


João Zilhão (Director, IPA, Instituto Português de Arqueologia) and António Martinho Baptista (Director, CNART, Centro Nacional de Arte Rupestre), September 21, 2001.

The following document is copied verbatim from the following web site: ‘s_reply_%20to_CAR-ICOMOS_ Alqueva_ report_ September

1. IPA/CNART express their satisfaction for the courteous, considered and balanced nature of Dr. Bertilsson’s report. Before commenting on the details, we want to emphasize that, throughout the process leading to its production, Dr. Bertilsson followed at all times what we believe to be proper scientific procedure, seeking information before forming an opinion and displaying sincere and due appreciation for the work carried out under difficult and time-stressed conditions by the CNART-led Alqueva recording team. This stands in marked contrast with previous CAR-ICOMOS work in Portugal, specifically the December 1994 mission to the Côa valley. This mission eventually led to a January 1995 report, signed by Jean Clottes, where it was suggested that the best way to preserve the Côa valley petroglyphs was submersion by the reservoir of the Foz Côa dam, then under construction. That mission clearly exceeded its mandate, and its suggestions were submitted with no consideration whatsoever for the opinion of Portuguese colleagues, ending up in what were clearly nonsensical recommendations, as subsequent events demonstrated. Dr. Bertilsson’s procedure and report represent a clear break with such past experience, and constitute a sound basis upon which CAR-ICOMOS can establish itself as an expert body respected in the world of archaeology as a whole. We can only hope that his example will be followed by others in the future.

2. We gladly recognize, therefore, that this is the kind of expert assessment work the world of rock art badly needs in order to establish itself as a fully professional field of scientific research. Nonetheless, IPA/CNART express their regret that Dr. Bertilsson did not provide an unambiguous statement on the nature of the declarations reproduced in the front page of the September 8 issue of the Portuguese weekly newspaper EXPRESSO. These declarations were attributed to Dr. Zuechner, misidentified as “secretary-general of CAR-ICOMOS”. Even if Dr. Zuechner’s authority to produce such declarations, supposedly on behalf of UNESCO, is implicitly disavowed by Dr. Bertilsson’s report, it would have been better, if nothing else for the sake of clarity, to acknowledge it explicitly.

3. Dr. Bertilsson’s references to the use of the bichromatic method by CNART are probably due to a misunderstanding of the situation, easily explained due to the short duration of his stay. Contrary to what the uninformed reader might be led to believe, CNART has never used the bichromatic method as a standard routine procedure. Throughout the several years of recording work in the Côa valley, for instance, this method was never used, not even once. In the Alqueva, CNART used it in a very small number of Guadiana panels for two reasons. First, because CNART used the Alqueva project as a field school, an opportunity to train a new generation of Portuguese archaeologists in the techniques of rock art recording, including those that were widely used in the past but are currently abandoned or out of favor. Second, because this was a rescue operation, where time is the paramount conditioning factor, and, therefore, rapidity and cost-effectiveness take precedence over other considerations. We are sure that Dr. Bertilsson understands these reasons very well, since he does not object to our use of other recording techniques that imply potentially damaging, even if minimally so, contact with the decorated surfaces, such as latex molding. Even if they are widely used in rock art studies, we have chosen to avoid the application of such techniques under normal research conditions, as is the case in the Côa valley. We used them in the Guadiana because submersion of this rock art means that it will be unavailable for study for several decades. Under such circumstances, we believe that production of replicas of the decorated surfaces that are as exact as current technology permits must be at the top of research priorities.

4. We wish in any case to stress that we fully agree with Dr. Bertilsson and CAR-ICOMOS in that the bichromatic method, and indeed any other application of paint over engraved rock surfaces, should be avoided. In fact, over the last decade, as was widely acknowledged in the wake of publication and discussion of the Côa valley work, Portuguese rock art researchers have pioneered the development of alternative, non-intrusive, and more performing techniques for the recording of petroglyphs. We have also designed methods of presenting rock engravings to the public that effectively dispense with the use of paint to enhance the visibility of the motifs. Such a use is still widespread in many countries, particularly in Scandinavia, where petroglyphs are routinely filled with white or red paint in order to facilitate observation by the untrained eye of the visitor, in spite of the growing international consensus that the practice should be abandoned. IPA/CNART therefore cannot but welcome the position of CAR-ICOMOS in these matters so clearly stated by Dr. Bertilsson, and look forward to the recommendations to that effect that CAR-ICOMOS will no doubt present to the governments concerned. In the framework of different international collaborative projects, including the Swedish-led RockCare project directed by Dr. Bertilsson himself, IPA/CNART have made their know-how available to all those that requested it, and remain willing to assist CAR-ICOMOS in obtaining worldwide adherence to the standards in recording and presentation of petroglyphs to the public that have been pioneered by Portuguese researchers.

5. Dr. Bertilsson suggests that “modern high-tech methods”, such as laser scanning, be used to complement the Guadiana recording work. Over the last three years, IPA/CNART, in collaboration with INETI, have carried out an experimental project to apply high-resolution laser scanning and stereophotogrammetry to the recording of the Côa valley rock art. With regard to laser scanning, this project uses technology and know-how initially developed at INETI (Instituto Nacional de Engenharia e Tecnologia Industrial) for military and industrial purposes. The results obtained show that even when the best quality, most expensive sensors currently available are used, the resolution of available technology is still insufficient. Fine-line engravings, such as those that make up the vast majority of the Côa valley Paleolithic art, remain invisible even to the best possible hardware/software combinations. The method works quite well for the larger pecked and abraded motifs but still requires intensive intervention of highly trained people in the final image-processing stage of the recording process. Our conclusion is that these techniques are extremely valuable for the purpose of obtaining accurate, three-dimensional digital descriptions of both the rock-art motifs and the rock surfaces/volumes on which such motifs are inscribed in situations where traditional molding techniques should be avoided because of preservation issues, or cannot be used because of the sizes or the shapes of the volumes involved. This is the case, for instance, when production of 1:1 replicas of large panels is needed for museographic purposes, and indeed it was for such purposes that the IPA/CNART/INETI project was initially designed. The systematic use of such techniques in the Alqueva would be too expensive, too slow, and too cumbersome. Moreover, the results obtained would in any case be qualitatively inferior to those obtained with traditional recording techniques. Quite simply, our experience indicates that the best hardware currently available for the Alqueva work is the extremely powerful combination of a well-trained human hand with an experienced human eye. That said, the use of stereophotogrammetry, for instance, may be of great help in securing the digital records necessary for the future production of replicas for a museum audience, should indeed be used for that purpose where a selection of the best-quality Alqueva panels is concerned, and IPA/CNART will forward such a recommendation to EDIA.

6. IPA/CNART completely agree with Dr. Bertilsson that the rock art panels found at Alqueva should not be cut loose and relocated. This is simply not an issue. In fact, statements to that effect were already clearly made in the preliminary report presented by CNART last May , in the wake of CNART’s first assessment of the situation, following initial reporting of the newly found rock art sites located in the Portuguese margin of the Guadiana.

7. Empirical observation of the Tagus Valley rock art, which for the most part has been submerged for the last 30 years, ever since the reservoir of the Fratel dam was filled up in the early 1970s, indicates that the Guadiana rock art, made of similar motifs, with similar techniques, on similar kinds of rocks (greywacke, etc.), and in a similar river margin setting, will not be significantly affected by a long period of submersion. Where this issue is concerned, therefore, IPA/CNART is of the opinion that the burden of proof lies squarely on the side of anyone believing otherwise.

8. As publicly stated by EDIA and the Minister of Planning in a press conference of May 14, 2001, the ensemble of finds made in the framework of the Alqueva archaeological salvage project, including the rock art, will be presented to the public through a Museum facility to be built in the region.

9. IPA/CNART are devoted to the study, protection and promotion of archaeological heritage at least as much as all other bona fide colleagues and institutions in the profession, in Portugal and elsewhere. As such, we would naturally prefer a situation where the Guadiana rock art continued to be enjoyed in its current setting for many generations to come. However, IPA/CNART acknowledge that they live in a world where conflicts between such preferences and the needs of society as a whole are inevitable. When such conflicts arise, the costs and benefits of all possible solutions must be weighed and decisions must be taken after careful consideration of the different issues. The potential benefits of the Alqueva dam were discussed for decades, and the Portuguese government eventually made the decision to build it. The role of archaeologists in such a situation is that of carrying out the mitigation measures deemed appropriate and in a framework of costs determined by the overall budget of the project developer. Situations such as those which occurred six years ago in the Côa valley are entirely exceptional and IPA/CNART in no way want to be part of actions which might be interpreted as suggesting that they should instead be the norm.

10. Where the Guadiana rock art is concerned, IPA/CNART understand and welcome the concern of colleagues worldwide. We are well aware that many countries have no rock art at all, or only have rock art of minor quality or not very well preserved. We understand the natural instinct of colleagues from such countries to oppose even the concept that rock art may be submerged or otherwise affected by development. But modern societies constantly face the need to make choices on which parts of their archaeological heritage must be preserved unchanged, and which should be transformed into historical documentation or removed to museum facilities, and this applies to all kinds of archaeological heritage, including rock art. Ranking the importance and significance of archaeological resources, including rock art, is therefore necessary, even if it is one of the most difficult tasks faced by institutions devoted to their management. But this is inevitable, particularly in countries that are archaeologically rich. Such is the case with Portugal and Portuguese rock art, and that is both our fortune and our problem. But IPA/CNART do not shy away from the responsibility of dealing with it and, in this context, wish to make it clear that the Guadiana rock art, undoubtedly of value and significance, must be placed, in Portuguese terms, in a third-from-the top category. In our opinion, the top level is occupied by the Côa valley rock art, which is in a category of its own. The second level is occupied by the Neolithic and Copper Age rock art of the Tagus valley, the rich ensemble of rock-shelters with well preserved naturalistic, subnaturalistic and abstract Neolithic and Copper age paintings that dot the countryside of many interior regions of Portugal, and by the recently found ensemble of Paleolithic engravings of the upper Sabor. The Guadiana ensemble, together with the rock art of the Northwest, among others, is in a third level, still of national significance but clearly not representing a heritage value of such importance as to be deemed an absolute obstacle to the construction of a dam which Portuguese society, after decades of debate and controversy, considered as a strategic economic facility, and, accordingly, legitimately decided to build.

11. IPA/CNART warmly welcome the generous offer of assistance made by CAR-ICOMOS, and will no doubt take advantage of it, should the need arise. IPA/CNART reassert that all the recording work will be completed before the end of the year, well in advance of the inundation of the Guadiana rock art.