CONTENTS 1: Introduction 1.1 A disappointingly large amount of mud 1 1.2 A systemic way of understanding and coevolution 3 1.3 Estuaries and tidal rivers 4 1.4 Outlook: research scope and questions 5 2: Complexity Th eory 2.1 A systemic approach 9 2.2.1 Introducing complexity theory 10 2.2.2 Elements of structure 13 2.2.3 Agency and boundary judgements 15 2.2.4 Elements of process 17 2.2.5 Simplistic versus complex complexity 20 2.3.1 Investigating complex complexity 22 2.3.2 Longitudinal investigation and agents representation 24 2.4.1 Reviewing complexity theory 26 2.4.2 Using concepts and fi ndings from natural science? 26 2.4.3 Creating metaphors? 28 2.4.4 Introducing something new? 29 2.4.5 Being modest 31 2.5 Conclusions 32 3: Coevolution and Decision Making 3.1 Systems interaction and coevolution 35 3.2.1 Introducing coevolution 36 3.2.2 Perceptible and blind reciprocal selection 39 3.2.3 Selection patterns, adoption and adaptation 42 3.2.4 Strange attractors and attractor basins 45 3.2.5 Th e matter of direction 49 3.3.1 Conceptualising coevolution 51 3.3.2 Initial selection pressures 53 3.3.3 Selection patterns: boundary judgements and variation 53 3.3.4 Th e projected attractor basin 55 3.3.5 Consequences of selection and action 55 3.3.6 (Not) A sequential process 56 3.4 Two case studies 57 4: Modifying the Unterelbe between 1996 and 2007 4.1 Introduction 63 4.2.1 Th e physical system 64 4.2.2 Th e policy action system and the societal environment 66 4.3.1 January 1996 June 1996 68 4.3.2 June 1996 July 1996 69 4.3.3 July 1996 May 1997 71 4.3.4 June 1997 October 1998 72 4.3.5 October 1998 December 1999 75 4.4.1 December 1999 April 2002 76 4.4.2 April 2002 February 2003 78 4.4.3 February 2003 May 2004 81 4.4.4 May 2004 October 2004 84 4.5.1 October 2004 September 2005 89 4.5.2 October 2005 December 2006 93 4.5.3 Final observations 96 5: Analysis of the Unterelbe Case 5.1 Introduction 99 5.2.1 Initial selection pressures (January 1996 December 1999) 99 (January 1996 December 1999) 5.2.2 Selection patterns (January 1996 December 1999) 101 (January 1996 December 1999) 5.2.3 Th e projected attractor basin 105 (January 1996 December 1999) 5.3.1 Consequences of selection and action 107 (December 1999 October 2004) 5.3.2 Th e actual attractor and its selection pressures 110 (December 1999 October 2004) 5.3.3 Selection patterns 111 (December 1999 October 2004) 5.3.4 Th e projected attractor basin 117 (December 1999 October 2004) 5.4.1 Consequences of selection and action 117 (October 2004 November 2006) 5.4.2 Th e actual attractor basin and its selection pressures 120 (October 2004 November 2006) 5.5 Final observations 120 (October 2004 November 2006) 6: Modifying the Westerschelde between 1993 and 2007 6.1 Introduction 127 6.2.1 Th e physical system 128 6.2.2 Th e policy action system and societal actors 131 6.3.1 July 1993 December 1994 133 6.3.2 January 1995 January 1996 134 6.3.3 February 1996 October 1996 136 6.3.4 November 1996 May 1999 138 6.4.1 May 1999 September 2000 139 6.4.2 October 2000 December 2000 144 6.4.3 January 2001 December 2001 145 6.4.4 January 2002 December 2002 149 6.5.1 January 2003 October 2003 154 6.5.2 November 2003 December 2003 158 6.5.3 January 2004 August 2004 160 6.5.4 September 2004 December 2004 163 6.5.5 November 2004 July 2005 167 6.5.6 Final observations 169 7: Analysis of the Westerschelde case 7.1 Introduction 171 7.2.1 Initial selection pressures 171 (July 1993 May 1999) 7.2.2 Selection patterns 173 (July 1993 May 1999) 7.2.3 Th e projected attractor basin 176 (July 1993 May 1999) 7.3.1 Consequences of selection and action 177 (May 1999 December 2002) 7.3.2 Th e actual attractor and its selection pressures 179 (May 1999 December 2002) 7.3.3 Selection patterns 180 (May 1999 December 2002) 7.3.4 Th e projected attractor basin 185 (May 1999 December 2002) 7.4.1 Consequences of selection and action 186 (December 2002 December 2006) 7.4.2 Th e actual attractor and its selection pressures 189 (December 2002 December 2006) 7.4.3 Selection patterns 190 (December 2002 December 2006) 7.5 Final observations 195 (December 2002 December 2006) 8: Th rough the Attractor Basin 8.1.1 Introduction 199 8.1.2 Two dissimilar cases, two dissimilar trajectories 200 8.2.1 Dealing with real selection pressures 202 8.2.2 Th e attempts to select perceptibly and intentionally 204 8.2.3 Th e occurrence of blind selection 205 8.2.4 Unintended, unobserved and unexpected 207 8.3.1 Types of policy action systems 209 8.3.2 Singular policy action system 209 8.3.3 Composite policy action system 212 8.3.4 Evolving disposition of policy action systems 214 8.4.1 Systems under pressure 216 8.4.2 Between interference, parasitism and symbiosis 217 8.5.1 Six aspects of decision making in coevolving systems 220 9: Th e Gentle Art of Coevolution 9.1 Recapitulation 226 9.2 Surviving coevolution 228 9.3.1 Craving simplicity 230 9.3.2 Th e inescapable reality of complexity 232 9.4.1 Building on the premise of complexity 233 9.4.2 Decision making as reciprocal selection 234 9.4.3 Resilience and turbulence 237 9.4.4 Complexity and anxiety 238 9.5 Final remarks 239 References 243 Appendix 1: Data case Unterelbe 250 Appendix 2: Data case Westerschelde 258 Appendix 3: List of translations and abbreviations 271 Samenvatting 273 Acknowledgements 280