A comprehensive methodology for the visual impact assessment of mines and quarries

Since the 60s, several multidisciplinary studies have been carried out worldwide to investigate the perception of landscape modification and define appropriate methodologies of Visual Impact Assessment (VIA). The criteria typically applied to evaluate the visual impact due to landscape alteration can be categorized into two classes: direct and indirect approaches (i.e. respectively perception test and numerical quantification of landscape modification). Both the approaches intend to overcome the limit of the judgment subjectivity in the evaluation process and its dependence on the observer’s specific characteristics. As a matter of fact, the effect of landscape modification needs to be objectively estimated when the VIA procedures are mandated by regulatory policies and accurate evaluation techniques are required to support decision-making. The Lvi indicator (Level of visual impact) has been formerly proposed as a tool to enable the objective quantification of the visual impact magnitude produced by extensive surface excavation (i.e. mines and quarries). This article discusses the integration of the Lvi indicator into a comprehensive Landscape Assessment Model (LAM), which includes the three succeeding steps of the visual impact assessment procedure: 1. the identification of the Key Observation Points (KOPs) (i.e. intervisibility analysis), 2. the quantification of the visual impact magnitude from the selected KOPs (i.e. visual impact estimation), 3. the comparison with predefined levels of acceptable landscape modification (i.e. visual impact evaluation). The proposed assessment procedure has been applied to a quarry of inert materials located in Sardinia (Italy) to highlight and discuss the practical implications of the proposed procedure and its inherent limitations.