Assessment of visual impact induced by surface mining with reference to a case study located in Sardinia (Italy)

Surface mining and quarrying typically generate a considerable number of environmental impacts among which landscape alteration remains one of the most significant. Although landscape alteration does not directly affect public health, it may produce an adverse reaction among potential observers and compromise the use and potential growth of the surrounding territory. In order to assess the impact produced by surface excavation, some aspects of landscape modification can be objectively measured, such as the extent of the visible alteration, its shape and the chromatic contrast with the surroundings. With reference to a case study located in Sardinia, this article discusses the implementation of two different visual impact assessment methods, one defined by the EC decision 272/02 (Commission Decision 2002), the other previously proposed by the authors of the present article and based on the estimation of the impact indicator Lvi (level of visual impact). The comparison of the results proves that the method established by the EC decision leads to the underestimation of the visual impact for alterations which are significantly wider than their height. On the other hand, the implementation of the Lvi method clearly shows how the indicator is affected by the quarry’s lateral extent and suggests the possibility of calculating a global impact factor LVI to be associated to a given route, considering the variability of the visual impact with the curvilinear abscissa of the route itself.