Assessment of visual impact due to surface mining with the Lvi method

摘要

Surface mining and quarrying typically generate a number of environmental concerns among which landscape alteration is one of the most significant.Although landscape and visual impact does not directly affect public health,it usually generates a negative reaction among potential observers,sometimes influencing the socioeconomic development of the surrounding impact territory.The landscape and visual impact assessment involves individual perceptions,aesthetic tastes and visual comprehension; however,some aspects of landscape modification can be objectively measured in order to quantify the magnitude of change.The article summarizes the results of previous studies focused on the implementation of the Lvi (Level of Visual Impact) method to a variety of cases within the European territory and discusses the adequacy of the method in providing an objective estimation of the visual damage produced by surface mining and quarrying.The visual impact indicator Lvi takes into account two parameters among those physically measurable: the extent of the visible alteration and the chromatic contrast between the color of the bare rock and that of the surrounding landscape.Both parameters can be quantified by processing one or more digital images taken from the most significant viewpoints (public roads,towns,villages,touristic sites,etc.).The article also includes the results of a recent study where the use of a global impact factor L VI to be associated to a given route has been proposed,in order to account for the variability of the visual impact along the route.Other studies proved the visual impact indicator Lvi to be significantly correlated with the subjective perception of potential observers,the results of a test carried out in the University of Cagliari are briefly reported in this article.Some critical aspects regarding the variability of the results on the basis of the shooting conditions (type of camera,season and time of the day,etc.) are discussed,as well as the possibility of developing the assessment procedure as to include the estimate of the ante-operam quality of the impact territory under exam and the number and type of people who are likely to observe the landscape modification.