The Vajont dam disaster is a world-known case of man-made hydrogeological catastrophe. On 9 October 1963, an about 2 kmq rock mass, detached from a side of the Mount Toc (placed between Veneto and Friuli regions, Italy), sliding into an artificial dam lake. It moved laterally some 360 m, and 140 m upward on the opposite valley flank. The great part of the landslide moved as a whole, propagating water waves which eroded soils of Vajont valley up to 235 m above the reservoir level. The adjoining villages of Erto and Casso had been "touched lightly" by waves. Toward Pieve valley, water swept across the dam and down the Vajont Gorge, reaching an estimated wave height of 80 m at gorge mouth. Inside the gorge, the water mass provoked air compression that, in turn, was energetically pushed out of the gorge mouth. The airflow energy has been evaluated to be about twice than that occurring at Hiroshima with the explosion of the atomic bomb. Then, the water wave reached the Piave valley. Longarone and other villages (Pirago, Villanova, Rivalta, Faé) were destroyed and almost 2000 persons died and many others were injured. Notwithstanding the impressive development of energy, the Vajont dam remained undamaged. Two opposing interpretations have been proposed in literature: the disaster was completely foreseeable (see for instance: Roubault, Pent-om prévoir les catastrophes naturelles?, 1970) or, vice-versa, nobody would have been able to predict it (Selli and Trevisan, Caratteri e interpretazione della frana del Vajont, 1964; Semenza, Sintesi degli studi geologici sulla frana del Vajont dal 1959 al 1964, 1965). According to current concepts of environmental policy and epistemology of geology, a review of both the decision making-process which led to the disaster and the consequent post-disaster policy, are proposed. It can be argued that uncertainty about: (i) the depth of the slip surface (i.e. the volume of the landslide), (ii) the compactness of the slide (that involved a presumed division into two parts of the mass movement) and (iii) the low shear strength of the beds at the slip surface (and so a rate of the sliding higher than a predicted one), had been reduced at a time consistent with a change of management strategy oriented toward the safety people. The scientific debates which followed the disaster had influenced by State's Interest, reaching a level of a true ideological conflict which reflected exasperated tensions growing inside the Society. The cultural context was that of a post-agricultural society commit oneself to build a new national identity. An identity of a rising industrial power. The post-disaster policy had biased data interpretation, data production, memory and scientific communication of experts and researchers. Dealing with the drawing of guidelines about environmental policy and hazards managements, can be useful to try to understand the reasons of such errors. A number of general features must be considered and, among these: the hydraulic paradigm and the idea of dominion of the nature, the hegemony of the ruling bloc and the making of a social justice concept, the historical conjuncture and the political practices. In 1976 Erto was denoted as "national monument" by virtue of its architectonic value. Nevertheless, the Vajont dam and its surrounding landscape, including the homonym gorge and the destroyed villages, currently represent, as a whole, the "intangible expressions" (cf. Vecco et al., A definition of cultural heritage: from the tangible to the intangible, 2010) of the human action which led to the disaster. They have acquired a preeminent socio-political value and, as a consequence, need to be known and protected. Moreover, the management of the interactions systems of Landscapes, Heritage and Culture (cf. e.g. Mascari et al., Landscapes, Heritage and Culture, 2009) must to be improved.
The Vajont dam disaster as a paradigm of a building national identity.
Delle Rose M
2011
Abstract
The Vajont dam disaster is a world-known case of man-made hydrogeological catastrophe. On 9 October 1963, an about 2 kmq rock mass, detached from a side of the Mount Toc (placed between Veneto and Friuli regions, Italy), sliding into an artificial dam lake. It moved laterally some 360 m, and 140 m upward on the opposite valley flank. The great part of the landslide moved as a whole, propagating water waves which eroded soils of Vajont valley up to 235 m above the reservoir level. The adjoining villages of Erto and Casso had been "touched lightly" by waves. Toward Pieve valley, water swept across the dam and down the Vajont Gorge, reaching an estimated wave height of 80 m at gorge mouth. Inside the gorge, the water mass provoked air compression that, in turn, was energetically pushed out of the gorge mouth. The airflow energy has been evaluated to be about twice than that occurring at Hiroshima with the explosion of the atomic bomb. Then, the water wave reached the Piave valley. Longarone and other villages (Pirago, Villanova, Rivalta, Faé) were destroyed and almost 2000 persons died and many others were injured. Notwithstanding the impressive development of energy, the Vajont dam remained undamaged. Two opposing interpretations have been proposed in literature: the disaster was completely foreseeable (see for instance: Roubault, Pent-om prévoir les catastrophes naturelles?, 1970) or, vice-versa, nobody would have been able to predict it (Selli and Trevisan, Caratteri e interpretazione della frana del Vajont, 1964; Semenza, Sintesi degli studi geologici sulla frana del Vajont dal 1959 al 1964, 1965). According to current concepts of environmental policy and epistemology of geology, a review of both the decision making-process which led to the disaster and the consequent post-disaster policy, are proposed. It can be argued that uncertainty about: (i) the depth of the slip surface (i.e. the volume of the landslide), (ii) the compactness of the slide (that involved a presumed division into two parts of the mass movement) and (iii) the low shear strength of the beds at the slip surface (and so a rate of the sliding higher than a predicted one), had been reduced at a time consistent with a change of management strategy oriented toward the safety people. The scientific debates which followed the disaster had influenced by State's Interest, reaching a level of a true ideological conflict which reflected exasperated tensions growing inside the Society. The cultural context was that of a post-agricultural society commit oneself to build a new national identity. An identity of a rising industrial power. The post-disaster policy had biased data interpretation, data production, memory and scientific communication of experts and researchers. Dealing with the drawing of guidelines about environmental policy and hazards managements, can be useful to try to understand the reasons of such errors. A number of general features must be considered and, among these: the hydraulic paradigm and the idea of dominion of the nature, the hegemony of the ruling bloc and the making of a social justice concept, the historical conjuncture and the political practices. In 1976 Erto was denoted as "national monument" by virtue of its architectonic value. Nevertheless, the Vajont dam and its surrounding landscape, including the homonym gorge and the destroyed villages, currently represent, as a whole, the "intangible expressions" (cf. Vecco et al., A definition of cultural heritage: from the tangible to the intangible, 2010) of the human action which led to the disaster. They have acquired a preeminent socio-political value and, as a consequence, need to be known and protected. Moreover, the management of the interactions systems of Landscapes, Heritage and Culture (cf. e.g. Mascari et al., Landscapes, Heritage and Culture, 2009) must to be improved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
