Summary

The United Nations Population Fund (UNFPA) has stated that in 2008, for the first time in history, more than half the population of the world was living in towns and cities. It is predicted that by 2030 this number will increase to 60% of the population [1]. The increasing size of urban areas, the growing population which requires us to convert more wilderness to agricultural or industrial use, and the more intensive use of that agricultural land, have combined to put the countryside under enormous pressure. As a result, the last few decades have revealed a growing social unease of the aesthetics of the landscape. Governments and citizens are becoming ever more concerned with the visual display of their everyday environment, both urban and rural. More and more, landscape, and particularly its Aesthetic Quality, are conceived as a resource - natural and societal -, highly fragile and capable of disappearing. Un-planned constructions, environmental hazards and bad usage of the territory, have influenced to its degradation, and so it becomes necessary to define conservation guidelines.

At the same time, increasing concentration of carbon dioxide in the atmosphere has caused a fear towards global warming. This fear, and the realisation that oil production is at, or near, its peak, have driven many countries to seek decarbonisation of their energy economies. Renewable energies, in particular wind energy and solar energy facilities, represent an attractive option in the move towards decarbonisation. However, these technologies frequently encounter public resistance, largely directed at their poor integration into the landscape. It is therefore important that the public resistance to renewable energy encounters be properly understood, so that, if needed, such facilities can be deployed on a large scale, without damaging the environment or people's perceptions of it.

To protect the visual quality of the landscape, it is necessary to understand it, and the first step to do so, is by carrying out a Visual Impact Assessment (VIA), which aims to identify and evaluate physical and perceptual landscape components that determine whether a particular landscape is aesthetically pleasing or not. Within the EU, countries and regions regulate the sustainability of their landscapes according to the Council Directive 85/337/EEC of 27 June 1985 on the assessment of the effects of certain public and private projects on the environment, also known as the Environmental Impact Assessment Directive. The EIA Directive requires Environmental Impact Assessments to be carried out for certain construction projects (particularly large-scale)
prior to their development, to ensure that the possible environmental consequences generated by the projects are identified and assessed before the constructions are authorised. The visual impact which is induced by human action on a landscape is one type of environmental impact which must be considered in EIA. Consequently, European countries and/or regions which have developed landscape laws according to the Commission's Directives, are legally committed to perform Visual Impact Assessments, as part of the project's EIA.

Although more and more tools are being developed for the execution of VIA, there is still not a universal tool which can be used by different types of users within the field of landscape research and landscape planning. Moreover, the tools developed are often too complicated, or too specific to be useful in practice, and in particular, in Environmental Impact Assessments.


Landscape analysis offers a wide spectrum of methodologies and tools which are based on different theoretical foundations, and which pursue varying objectives. The decision on which methodology to adopt is determined by the definition of the term landscape and on the objective pursued in the analysis. Studies in visual impact of landscapes have followed three main lines of investigation: The  Expert Approach, the Public Preference Approach and the Holistic Approach.

The objective of this work is to develop reliable and easily-applicable tools to quantify the Visual Impact of human interventions on the landscape, by means of a potentially generalisable methodology. Three case studies are presented, whereby each study applies a separate approach to VIA. Each investigation aims to advance from the findings of the previous one, complementing the methodology with new tools.

In the first study, an indicator is developed to measure the magnitude of the aesthetic impact of wind farms, using the Expert Approach. The indicator combines tangible measures of visibility, colour, fractality and continuity which can be taken from photographs. Value functions are constructed for each variable and incorporated into the indicator. This indicator is used to calculate the objective aesthetic impact of five wind farms. Statistic comparison of the indicator results with a population survey shows that the indicator correctly represents the order of impact as perceived by the population sample, and is thus an appropriate objective measure of aesthetic impact of wind farms.

Continuing with the line of thought and results of this study, the second investigation first develops a similar indicator for solar power plants, and subsequently combines it with a Semantic Differential Analysis to evaluate variations in subjective human perception; thus introducing a Holistic Approach. The study proves that the combined use of an objective indicator and a subjective study, faithfully explains user preferences.

The third study improves the reliability of the Semantic Differential Analysis, to evaluate the visual impact of different types of human interventions, in a Public Preference Approach. This is done by incorporating the Intraclass Correlation Coefficient tool, which is applied to validate the semantic space of the perceptual responses and to determine the number of subjects required for a reliable evaluation of the scenery.

Finally, the methodology and the tools developed are analysed for reliability, validity, generalisability and applicability, with particular reference to VIA as part of the Environmental Impact Assessment.

This work has been carried out following the official procedure for the attainment of a European PhD. During the course of the PhD, the candidate has performed research studies at the University of Oxford (Oxford, UK) for a period of six months. In addition, this doctoral thesis is compiled in a "publications" format, in accordance with the requirements of the Department of Engineering Projects, of the Polytechnic University of Valencia (Valencia, Spain). Two articles which correspond to the first two studies, have been published in the scientific journal Renewable and Sustainable Energy Reviews. To date, a third paper relating to the third study has also been presented to Environmental Impact Assessment Review, for its evaluation. Additionally, the general content outlined in the literature review has also been published in the book entitled Visual Perception published by Novapublishers.



Bibliography

[1] United Nations Population Fund. Annual Report 2008. www.unfpa.org/about/report/2008/en/index.html, page 20, 2009.