Comparative Assessment of Large Dam Projects

Transcription

1 ZIT-Publik 23/2007 Veröffentlichungen des Zentrums für Interdisziplinäre Technikforschung der TU Darmstadt Elke Petersson Comparative Assessment of Large Dam Projects -A Challenge for Multi-Criteria Decision Analysis- Darmstadt, January 2007 Hochschulstrasse 1 D Darmstadt Fon: +49 (0) Fax: +49 (0) zit@zit.tu-darmstadt.de

2 ZIT-Publik 23/2007 Veröffentlichungen des Zentrums für Interdisziplinäre Technikforschung der TU Darmstadt Zugleich Dissertation an der TU Darmstadt unter dem selben Titel (D 17) Die Autorin dankt dem Zentrum für Interdisziplinäre Technikforschung (ZIT) der TU Darmstadt für die freundliche Unterstützung der Veröffentlichung Das Werk einschließlich seiner Teile ist urheberrechtlich geschützt. Jede Verwertung ist ohne eine Zustimmung der Verfasserin unzulässig. Dies gilt insbesondere für Vervielfältigungen, Übersetzungen, Mikroverfilmungen und die Einspeisung und Verarbeitung in elektronischen Systemen. ISSN: ISBN:

3 The Ultimate Question of Life, the Universe and Everything Never again, cried the man, never again will we wake up in the morning and think Who am I? What is my purpose in life? Does it really, cosmically speaking, matter if I don t get up and go to work? For today we will finally learn once and for all the plain and simple answer to all these nagging little problems of Life, the Universe and everything!. You re really not going to like it, observed Deep Thought. Tell us! All right, said Deep Thought. The answer to the Great question Yes! Of Life, the Universe and Everything said Deep Thought. Yes! Is said Deep thought, and paused. Yes! Is. Yes!!!? Forty-two, said Deep Thought, with infinite majesty and calm. Forty-two! yelled Loonquawl. Is that all you ve got to show for seven and a half million years work? I checked it very thoroughly, said the computer, and that quite definitely is the answer. I think the problem, to be quite honest with you, is that you ve never actually known what the question is. Source: (Adams 1980)

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5 Acknowledgements ACKNOWLEDGEMENTS This doctoral thesis would not have been possible without the cooperation and assistance of numerous persons and institutions. Only their unreserved and generous support in many different ways enabled me to comprehensively analyse the role of MCDA methods in the large dam context. I thank Prof. Dr.-Ing. Manfred Ostrowski and Prof. Dr. rer. pol. Dirk Ipsen for their unconditional support of the dissertation and fruitful discussions on relevant disciplinary and interdisciplinary aspects. The work owes much to the scientific and personal advice from my colleagues Judith Elbe and Stephanie Petrasch at the Centre for Interdisciplinary Studies of Technology. I very much appreciate the time I could spend at Fondazione Eni Enrico Mattei (feem) in Venice that was made possible by a Marie-Curie Fellowship of the European Commission. The fruitful and inspiring collaboration with Prof. Carlo Giupponi and Jacobo Feás at feem marks the initial step forward in writing this doctoral thesis. Survey III is the result of these joint efforts. I also express my gratitude to Dr. Detlev Belke, Institute of Engineering Hydrology and Water Resources Management, for the joint mental struggle to hone the final reasoning. This work would not have been possible without the generous financial and temporal resources provided by Dr. Gerhard Stärk as the managing director of the Centre for Interdisciplinary Studies of Technology. Lahmeyer International made available information on their MOSES DSS and thus enabled one of the surveys carried out. I also thank all students that contributed to this doctoral thesis through their investigations and their student projects. Raphael Beecroft, Martha Gibson, and Jana Kaiser were of great help in proofreading the text and account for valuable linguistic improvements. In general, thanks go to my colleagues at the Centre for Interdisciplinary Studies of Technology and at the Institute of Engineering Hydrology and Water Resources Management for their creative input and time. Last but not least, thanks go to my family and friends for their unlimited patience, for mental and scientific support, for proofreading, and, most important, for their company. I

6 Abstract II ABSTRACT To face the continuously intensifying conflicts surrounding large dam projects, the international World Commission on Dams (WCD) has developed a set of recommendations on how to attain the equitable and sustainable development of water and energy resources. One such recommendation emphasises the need to, in the first instance, carry out a comprehensive options assessment in which both positive and negative project impacts are taken into consideration. The WCD furthermore recommends that this necessary assessment be formalised through the use of multi-criteria decision analysis (MCDA), although MCDA has up until now seldom been applied to the large dam context. This thesis will therefore pursue three aims: 1. To improve the understanding of the decision situation 2. To investigate the applicability of MCDA, its compatibility with the guiding principle of sustainable development and the significance of its results. 3. To recommend methodological improvements. This dissertation offers an understanding of large dams and their complex interactions with the natural environment and society s subsystems as a system and connects the MCDA theory to it. The thesis furthermore provides a link between the theoretical analysis of the strengths and weaknesses pertaining to MCDA independent of its specific methods and the findings of three analytical surveys, all of which bear direct relation to the comparison of large dam projects in practice. These surveys are: A comparison of computer-aided MCDA-tools for the large dam context, regarding methodological and content-related strengths and weaknesses. A retrospective quality analysis of a real-world application of one of the investigated tools for a large dam project in Laos. A theoretical reproduction of the decision to build a large dam in Turkey in the 1970s, applying one of the investigated tools. The strengths of MCDA can be found in its formalisation of the procedure, while its weaknesses are caused by methodological problems posed by the individual steps of the analysis. It will be shown that MCDA can be used to support the comparison of large dam projects. Splitting the decision into several more manageable decisions formalises the procedure, improves the understanding of the decision situation, increases the transparency of the decision-making process for the public, and facilitates conflict management. In practice, the weaknesses of the procedure are considered to outweigh its strengths. This is in particular due to the formalised aggregation of objective and subjective information. MCDA methods can be misleading, due to their tendency to overemphasise numerical results. The significance of the results is limited by the complexity reduction required. In addition to this, the assumptions necessary to the methods are loaded with a high level of uncertainty and the many small decisions to be made transform meanings. These effects interact in an irreproducible manner when integrated into an overall result. At the same time, it is impossible to validate the methods and to compare the individual methods with each other. Therefore, even the choice of a particular aggregation algorithm contains subjective preference information. As regards future application, MCDA should be broadened to include a form of quality management and its methods should only be understood as one element of a wider, explorative analysis of the decision situation. It will furthermore be necessary to create decision-making structures which avoid the export of problems into other sectors and which mediate between different interests.

7 Zusammenfassung ZUSAMMENFASSUNG Als Reaktion auf die sich verschärfenden Konflikte um große Talsperren, erarbeitete die internationale World Commission on Dams (WCD) Empfehlungen, wie einer gerechten und nachhaltigen Entwicklung von Wasser- und Energieressourcen entsprochen werden kann. Eine der Empfehlungen betont die Notwendigkeit, vorab einen Vergleich möglicher alternativer Projekte unter Berücksichtigung sowohl positiver als auch negativer Auswirkungen durchzuführen. Die WCD rät, die Bewertung mit Hilfe der Mehrkriterienverfahren (MCDA) zu formalisieren. Bisher liegen für den Vergleich von alternativen Talsperrenprojekten aber nur sehr wenig Erfahrungen mit diesen Methoden vor. Daher verfolgt die Dissertation drei Ziele: 1. Das Verständnis der Entscheidungssituation soll verbessert werden. 2. Die Anwendbarkeit der MCDA, ihre Kompatibilität mit dem Leitbild einer nachhaltigen Entwicklung und die Aussagekraft der Ergebnisse sollen überprüft werden. 3. Es sollen Empfehlungen für eine methodische Verbesserung gegeben werden. Die Arbeit beschreibt große Talsperren und ihre komplexen Wechselwirkungen mit der natürlichen Umwelt und mit der Gesellschaft als System und führt die theoretischen Grundlagen der MCDA ein. Der Hauptbeitrag liegt in der Verknüpfung einer theoretischen Diskussion von Stärken und Schwächen der Verfahren, unabhängig von einzelnen Methoden, mit Erkenntnissen aus drei analytischen Studien, die einen konkreten Bezug zur Praxis des Vergleiches von Talsperrenprojekten beinhalten: Vergleich computergestützter MCDA-Tools im Talsperrenkontext bezüglich methodischer und inhaltlicher Stärken und Schwächen. Retrospektive Qualitätsanalyse der praktischen Anwendung eines der untersuchten Tools im Planungsprozess für eine Talsperre in Laos. Nachbildung der Entscheidung für den Bau einer Talsperre in der Türkei aus den 1970er Jahren mit einem der untersuchten Tools. Die Stärken der MCDA liegen in der Formalisierung des Vorgehens, wohingegen die Schwächen in methodischen Problemen der Einzelschritte liegen. Die Arbeit hat gezeigt, dass MCDA den Vergleich von Talsperrenprojekten unterstützen können. Die Unterteilung der komplexen Entscheidung in viele kleine Entscheidungen strukturiert das Vorgehen, verbessert das Verständnis von der Entscheidungssituation, erhöht die Transparenz des Prozesses gegenüber der Öffentlichkeit und erleichtert das Konfliktmanagement. Insbesondere auf Grund des formalisierten Aggregationsschrittes überwiegen die Schwächen der Verfahren im konkreten Fall aber deren Stärken. Die Methoden verleiten zu einer unsauberen Implementierung in der Praxis, wie z.b. der Überbewertung der numerischen Ergebnisse. Die Aussagekraft der Methoden wird durch die erforderliche Komplexitätsreduktion stark eingeschränkt. Außerdem sind die getroffenen Annahmen von großer Unsicherheit geprägt und in vielen kleinen Entscheidungen werden Bedeutungen transformiert. Diese Veränderungen überlagern sich im Gesamtergebnis auf nicht nachvollziehbare Weise. Eine Validierung der Methoden und ein Vergleich unterschiedlicher Methoden ist dabei nicht möglich. Somit bildet auch der gewählte Aggregationsalgorithmus eine subjektive Präferenzinformation ab. Für zukünftige Anwendungen wird empfohlen, MCDA um eine Qualitätssicherung zu erweitern und sie nur als Teil einer weiter gefassten, explorativen Untersuchung der Entscheidungssituation zu sehen. Außerdem ist es wichtig, Entscheidungsstrukturen zu schaffen, die vermeiden, dass Probleme in andere Sektoren exportiert werden und die zwischen unterschiedlichen Interessen vermitteln. III

8 Table of contents TABLE OF CONTENTS LIST OF FIGURES VIII LIST OF TABLES X ACRONYMS XI 1 INTRODUCTION 1 2 THE LARGE DAM CONTEXT BASICS OF LARGE DAMS THE LARGE DAM CONTEXT SYSTEM THEORY OBJECT SYSTEMS ACTING SYSTEMS TARGET SYSTEMS THE WORLD COMMISSION ON DAMS (WCD) HISTORICAL DEVELOPMENTS FORMATION OF THE WORLD COMMISSION ON DAMS AND ITS FINAL REPORT GOVERNANCE ASPECTS OF THE WCD REACTIONS TO THE RESULTS OF THE WCD DEVELOPMENTS INITIATED BY THE WCD THE CHALLENGE OF DECISION-MAKING IN THE LARGE DAM CONTEXT DECISION SITUATION UNCERTAINTY 67 3 MULTI-CRITERIA DECISION ANALYSIS DECISION THEORY BASIC MODEL OF DECISION THEORY DECISION PHASES DECISION MAKER 76 IV

9 Table of contents CLASSIFICATION OF DECISION SITUATIONS ALTERNATIVE- AND VALUE-FOCUSED THINKING DECISION SUPPORT SYSTEMS (DSS) MULTI-CRITERIA DECISION ANALYSIS (MCDA) OPTIMISATION AND CHOICE MODELS CHOICE MODELS SELECTION OF AN APPROPRIATE MCDA METHOD MCDA AS SEEN BY THE WCD STRENGTHS AND WEAKNESSES OF MCDA IN THE LARGE DAM CONTEXT STRENGTHS OF MCDA DIFFICULTIES IN PROBLEM STRUCTURING DIFFICULTIES IN PERFORMANCE ANALYSIS DIFFICULTIES RELATED TO PREFERENCE INFORMATION AND AGGREGATION DIFFICULTIES RELATED TO IMPLEMENTATION OF MCDA INTRODUCTION TO SURVEYS SURVEY I: TOOLS FOR THE COMPARATIVE ASSESSMENT OF LARGE DAM PROJECTS DESCRIPTION OF ASSESSMENT TOOLS RESERVOIR SITE SELECTION IN TROPICAL ENVIRONMENTS (BABAN) GUIDELINES TO SUSTAINABLE WATER RESOURCES MANAGEMENT (DBU) PROJECT EVALUATION ON SUSTAINABLE DEVELOPMENT (DELFT) SUSTAINABILITY GUIDELINES AND COMPLIANCE PROTOCOL (IHA) MULTI-OBJECTIVE SCENARIO EVALUATION SYSTEM (MOSES) MULINO DSS (MDSS) WATERSTRATEGYMAN DSS (WSM) COMPARISON OF MCDA ASSESSMENT TOOLS SUSTAINABLE DEVELOPMENT PROBLEM STRUCTURING PERFORMANCE ANALYSIS PREFERENCE INFORMATION AGGREGATION SENSITIVITY ANALYSIS PARTICIPATORY AND DECISION-MAKING PROCESSES SUMMARY 154 V

10 Table of contents 5 SURVEY II: ANALYSIS OF THE MULTI-OBJECTIVE SCENARIO EVALUATION SYSTEM (MOSES) ANALYSIS OF THE DECISION CONTEXT: THE CONCEPTUAL PHASE ASSESSMENT OF ALTERNATIVE DAM OPTIONS: THE DESIGN PHASE SELECTION OF THE PREFERRED RESPONSE: THE CHOICE PHASE SCORING WEIGHTING AGGREGATION SUMMARY SURVEY III: APPLICATION OF MULINO DSS TO THE CEYHAN ASLANTAS DAM, TURKEY THE MULINO METHODOLOGY IN BRIEF THE CEYHAN ASLANTAS PROJECT TEST OF THE MULINO APPROACH ANALYSIS OF THE DECISION CONTEXT: THE CONCEPTUAL PHASE ASSESSMENT OF ALTERNATIVE DAM OPTIONS: THE DESIGN PHASE SELECTION OF THE PREFERRED RESPONSE: THE CHOICE PHASE SENSITIVITY ANALYSIS SUSTAINABILITY ANALYSIS DISCUSSION OF RESULTS SUMMARY CONCLUSIONS AND RECOMMENDATIONS DECISION SITUATION SUBJECT OF PLANNING: THE LARGE DAM CONTEXT TARGET SYSTEM: THE CHALLENGES OF SUSTAINABLE DEVELOPMENT PLANNING SYSTEM: THE INSTITUTIONAL SURROUNDING DECISION METHODS MULTI-CRITERIA DECISION ANALYSIS STRENGTHS AND WEAKNESSES OF MCDA METHODS RECOMMENDATIONS ON IMPLEMENTING MCDA FUTURE PERSPECTIVES 221 VI

11 Table of contents ANNEX A: GLOBAL CHANGE, GOVERNANCE AND ECONOMY 223 ANNEX B: THE NOTION OF SUSTAINABLE DEVELOPMENT 224 ANNEX C: STRENGTHS AND WEAKNESSES OF SIMULATION MODELS 231 ANNEX D : SCORING RULES USED IN MOSES APPLICATION 233 REFERENCES 241 VII

12 List of figures LIST OF FIGURES Figure 1: Schematic flowchart of dissertation... 5 Figure 2: Delimitation of dam and dam context... 7 Figure 3: Basic types of dams... 9 Figure 4: Dam components and partition of the reservoir Figure 5: Schematic representation of system science Figure 6: System definition Figure 7: General diagram for dynamic systems Figure 8: Sequence of large dam impacts on sectors Figure 9: A framework for assessing the impacts of dams on river ecosystems Figure 10: Distinction of shareholders and stakeholders Figure 11: The circular flow of income at national level Figure 12: The circular flow of income with irrational acting participants Figure 13: The strategic priorities developed by the WCD Figure 14: The challenges of decision-making Figure 15: Methods to approach uncertainty Figure 16: Elements of a decision model Figure 17: Classification of multi-participant decision makers Figure 18: Typology of decisions faced by a group Figure 19: Engineering decision-making Figure 20: Properties of wicked problems Figure 21: Problem solving in alternative- and value-focused thinking Figure 22: Continuous and discrete decision space Figure 23: Classification of MCDA approaches Figure 24: Interlinkage of real system and decision model in decision-making Figure 25: Difficulties in evidencing improved decision outcome for MCDA Figure 26: Documentation of indicators Figure 27: Project evaluation with respect to sustainable development Figure 28: Summary table for evaluation of new hydropower projects Figure 29: Guidelines for scoring Figure 30: Schematic procedure of MOSES VIII

13 List of figures Figure 31: Structure of MULINO DSS Figure 32: Framework of the WaterStrategyMan DSS Figure 33: Schematic procedure of MOSES application Figure 34: Connection between value margins and weights Figure 35: Classification of issues according to value scales and reference values Figure 36: Average importance factor per issue as function of discipline Figure 37: Range of weighted results for each issue and cumulative weight factor Figure 38: Total score of the project alternatives Figure 39: Weighted overall scores of the alternatives broken down into disciplines Figure 40: Relative performance of disciplines (all alternatives) Figure 41: Relative performance of disciplines (best four alternatives) Figure 42: Average and standard deviation of relative performance across disciplines..181 Figure 43: Economic attractiveness versus overall impact Figure 44: DPSIR scheme Figure 45: The Ceyhan Aslantas Project Figure 46: Swing weights Figure 47: Weighted profile graph with possible range of value scores Figure 48: Ranking obtained by weight variation Figure 49: Causes of uncertainty in multi-criteria decision analysis Figure 50: The challenges of decision-making Figure 51: Sustainability matrix Figure 52: The model base of a DSS IX

14 List of tables LIST OF TABLES Table 1: System complexity and indicators Table 2: Functions of object systems Table 3: Direct costs and benefits of large dam projects Table 4: WCD guidelines and classification Table 5: Differences in disciplinary approaches to modeling Table 6: Areas of research in decision theory Table 7: Performance matrix Table 8: Desired properties of criteria and alternatives Table 9: Classification of decision situations Table 10: Comparison of MODM and MADM approaches Table 11: Measurement scales in MCDA methods Table 12: Preference relation of MADM methods Table 13: Sources of uncertainty in large dam projects Table 14: Measurement scales Table 15: Meaning of weights in various MCDA methods Table 16: Types of compensation in MCDA methods Table 17: Core aspects covered in all surveys Table 18: Characteristics of selected assessment tools Table 19: Reservoir location criteria Table 20: Criteria to test the contribution of projects to sustainable development Table 21: Combinations of questions underlying the scoring of aspects Table 22: Evaluation issues with importance and weight factors of NT 2 study Table 23: Criteria presented for evaluation in WSM DSS Table 24: Compliance of NT 2 decision context with required properties Table 25: Average importance weight assigned to criteria of a discipline Table 26: Prerequisites for applicability of simple additive weighting Table 27: Performance Matrix Table 28: Hierarchical decision tree and swing weights Table 29: Sustainability Analysis Table 30: Composition of target dimensions in sustainable development X

15 Acronyms ADB AfDB AHP AM ASCE BMZ Asian Development Bank African Development Bank Analytic Hierarchy Process Analysis matrix ACRONYMS American Society of Civil Engineers Bundesministerium für Wirtschaftliche Zusammenarbeit und Entwicklung (Federal Ministry for Economic Cooperation and Development) BOT Build Operate Transfer CBA Cost-benefit analysis cf. confer DBU Deutsche Bundesstiftung Umwelt DDP Dams and Development Project DETR Department for the Environment, Transport, and Regions (Great Britain) DIN Deutsches Institut für Normungen e.v. DM Decision maker DPS Driving force Pressure State of environment DPSIR Driving force Pressure State of environment Impact Response DSS Decision Support System DVWK Deutscher Verband für Wasserwirtschaft und Kulturbau e.v. (German Association for Water, Wastewater and Waste) e.g. for example EA Ecological aspects EBRD European Bank for Reconstruction and Development EC Economic aspects ECA Export Credit Agency EEA European Environmental Agency IECO International Engineering Company EM Evaluation matrix et al. and others FA Financial aspects FAO Food and Agriculture Organisation GDP Gross domestic product GDSS Group Decision Support System GIS Geo Information System GNP Gross National Product gtz Deutsche Gesellschaft für Technische Zusammenarbeit (gtz) GmbH GUS Gemeinschaft unabhängiger Staaten (Commomwealth of Independent States) ha hectare HDT Hasse Diagram Technique HSBC Hongkong and Shanghai Banking Cooperation XI

16 Acronyms i.e. that is ICID International Commission on Irrigation and Drainage ICOLD International Commission on Large Dams IHA International Hydropower Association IRN International Rivers Network IUCN International Union for the Conservation of Nature IWG Interim Working Group IWRM Integrated water resources management KfW Kreditanstalt für Wiederaufbau (Reconstruction Loan Corporation) km³ square kilometre LAWA Bund/Länder-Arbeitsgemeinschaft Wasser LI Lahmeyer International m metre m³ cubic metre MAB Movimento dos Atingidos por Barragens (Brazilian Movement of Damaffected people) MADM Multi-attribute decision-making MAUT Multi-attributive utility theory MAVT Multi-attributive value theory MCDA Multi-criteria decision analysis MDM Multi-participant decision maker MODM Multi-objective decision-making MOP Multi-objective programming GP Goal programming MOSES Multi-objective scenario evaluation system MOU Memorandum of understanding MULINO Multi-sectoral, integrated and operational decision support system for the sustainable use of water resources at the catchments scale MW Megawatt n.s. not specified NAIADE Novel approach to imprecise assessment and decision environments NGO Non-governmental organisation NT 2 Nam Theun 2 study of alternatives OR Operations research OWA Ordered weighted average p. page PMF Probable maximum flood POE Panel of experts RD Regional development s second SA Social aspects SAW Simple additive weighting SD Sustainable development XII

17 Acronyms SDM Single decision maker SH Stakeholder SP State of preparedness TA Technical aspects TOPSIS Technique for order preference by similarity to ideal solution TRCOLD Turkish Commission on Large Dams UN-DESA United Nations Department of Economic and Social Affairs UNEP United Nations Environment Programme UNESCO United Nations Educational Scientific and Cultural Organisation US United States VDI Verein Deutscher Ingenieure (Association of German Engineers) WBGU Wissenschaftlicher Beirat der Bundesregierung Globale Umweltveränderungen (German Advisory Council on Global Change) WCD World Commission on Dams WCED World Commission on Environment and Development WEED Weltwirtschaft, Ökologie & Entwicklung e.v. WFD European Water Framework Directive WHO World Health Organisation WP Work Package WSM Water Strategy Man WWF World Wildlife Found XIII

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19 Introduction 1 INTRODUCTION Problem description Looking back at 5000 years of history, we find that dams are still a decisive technology. Constituting a barrier across a valley to contain the flow of water in the reservoir behind it, dams serve to balance the uneven distribution of water in space and time, raise the water head in the reservoirs and reduce or increase downstream runoff. They bring a variety of benefits ranging from agricultural irrigation, domestic and industrial water supply, electricity generation and flood protection to river navigability. These benefits should not overshadow their considerable impacts on the natural environment and society, such as changes of flora and fauna and their uses, resettlement, or health risks to name but a few. In their report Dams and Development - hereafter referred to as the report - the World Commission on Dams (WCD) analysed the effectiveness of the developments generated by large 1 dam projects in comparison to the expectations formulated at the planning stage. According to their findings, benefits of large dam projects tended to be smaller than planned, and negative impacts were often greatly underestimated. (WCD 2000) Despite these outcomes, improved living standards of a growing world population increase demands in particular for electricity and water (Altinbilek 2002). In contrast, water availability decreases, due to changes of environmental conditions such as climate or land use, but also due to the deteriorating quality of the water resources, because of existing intensive uses (Sanmugnathan et al. 2000). The environmental impact and the renewability of electricity generation is currently a subject of intensive discussions. Large dams are one way to increase the water supply and the generation of electricity. Depending on the specific use and the local conditions, alternative approaches to satisfy the demands may exist, for example, demand optimisation or other technologies. In other cases, namely water supply for irrigation and other consumptive uses in developing countries, the construction of large dams will be indispensable (Takeuchi et al. 1998). Acknowledging the need for dams motivates research on the selection of the most preferable dam alternative. According to the report, it is of particular importance to carry out a thorough assessment of options, in order to identify the most preferable planning alternative with regard to the required benefit(s) and the notion of sustainable development. The latter requires projects to be not only functional and economically viable but also acceptable from a broader social, environmental and economic perspective, as well as operative in the long run (WCED 1987). Both internal and external costs as well as benefits of a project are relevant. Options assessment compares the impacts of alternative courses of action against set (value) objectives. The information obtained is then used in subsequent decision-making to avoid wrong decisions and to improve decision outcome. In the past, this potential for choice and selection among alternative courses of action was often neither realised nor made explicit. Planning procedures for large infrastructure projects such as dams may be largely independent of procedures used for more routine projects, blurring boundaries between planning levels (Nichols et al. 2000). Furthermore, planned projects were often only compared to a limited set of objectives, in particular, technical functionality and economic viability. Over the past 50 years, environmental and social aspects have been increasingly introduced (Palmieri 2004). Acknowledging the need for large dams, the options assessment is complicated by the characteristics of the decision-making situation. The International 1 The International Commission on Large Dams (ICOLD) defines all dams with a height of 15 metres or more, measured from the lowest portion of the general foundation area to the crest as large (ICOLD 1984) cf. chapter

20 Introduction Hydropower Association (IHA) distinguishes three major decision situations in planning large dams or alternative projects (IHA 2004a). They are: identifying a technology (e.g. thermal, nuclear, wind, hydropower or solar power plants), a dam project (catchment, site, project size, uses, design, impacts), and the operation (discharge rules) that is most suitable. These three decision situations are interrelated and not necessarily addressed strictly consecutively. A respective planning process is iterative. New insights cast a different light on previous decision steps. The present dissertation will focus on project selection, in contrast to technology selection, to limit complexity. Nevertheless, the complexity related to the decision situation still poses a major challenge. By means of decision-making the planning system identifies the alternative that is expected to achieve the desired state of the subject of planning, i.e. the target, best. Aiming at sustainable development, the subject of planning comprises the large dam project and all economic, social, environmental and technical sectors related. Furthermore, a variety of organisational levels, from individuals to social groups, or from species to habitats, play an important role. To describe the subject of planning and its development over time in the wake of interventions by man, diverse quantitative and qualitative measurement units, their spatial and temporal distributions, as well as a variety of spatial and temporal scales need to be charged. Although external developments, such as climate and land use change, or economic developments cannot be influenced by the project, their possible influence on the project has to be taken into account. The planning system is shaped by the people actively participating in the decision-making process and by the formal setting thereof. Co-ordination and integration of experts with various disciplinary backgrounds, as well as of decision makers and stakeholders pursuing different interests (values), pose an additional challenge to options assessment. The target system reflects subjective personal or institutional preferences as regards the future performance of the subject of planning. In public decisions, the moral obligation of sustainable development is pursued as main target (cf. p. 1). It needs to be specified for individual decision contexts. In the case of large dam projects, it requires to give due consideration to the characteristics of the subject of planning elaborated above. The ambiguity contained in the notion of sustainable development in combination with the given complexity of the subject of planning and the diversity of interests in the planning system make it difficult to formulate clear-cut assessment criteria and preferences. Nevertheless to allow for the comparison of the different options, the information available on the subject of planning and the preferences represented in the target system need to be aggregated. All related processes should be transparent, to ensure acceptance of results. Any methodological approach used for options assessment should meet the corresponding challenges. Objective The WCD recommends the implementation of multi-criteria decision analysis methods (MCDA) to facilitate the options assessment of alternative dam projects at the planning stage (WCD 2000). MCDA is an umbrella term to describe a collection of formal, to some extent quantitative, approaches, which seek to take explicit account of multiple criteria in helping individuals or groups (Belton et al. 2002) to assess, integrate and compare the performance of alternative options against set targets. When deciding among distinct dam alternatives, as is the case here, only choice models (multi-attribute decision-making (MADM)) are applicable, however. Consequently, in this dissertation, as in the WCD documents, the terms MCDA and MADM will be used synonymously. The benefits quoted by the WCD correspond well to the challenges previously mentioned. MCDA enables the comparison of alternative courses of action with regard to a set of diverse and conflicting objectives and identify the most preferable one. Besides serving as justification and control in political processes, the 2