Sustainable Transformations of Water Supply Regimes. the Cuvelai-Etosha Basin in Central Northern Namibia
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Schriftenreihe 224 . Martin Zimmermann Sustainable Transformations of Water Supply Regimes. The Cuvelai-Etosha Basin in Central Northern Namibia. Herausgeber: Verein zur Förderung des Instituts der TU Darmstadt e.V. Zimmermann, Martin Sustainable Transformations of Water Supply Regimes. The Cuvelai-Etosha Basin in Central Northern Namibia. / Hrsg.: Verein zur Förderung des Instituts der TU Darmstadt e.V. Darmstadt: Eigenverlag, 2013 (Schriftenreihe IWAR 224) ISSN 0721-5282 ISBN 978-3-940897-22-0 Referent: Prof. Dipl.-Ing. Dr. nat. techn. Wilhelm Urban Korreferent: Prof. Dr.-Ing. Manfred Ostrowski Tag der schriftlichen Einreichung: 23.08.2013 Tag der mündlichen Prüfung: 08.11.2013 Alle Rechte vorbehalten. Wiedergabe nur mit Genehmigung des Vereins zur Förderung des Instituts - der Technischen Universität Darmstadt e.V., Fontanestraße 8, D-64291 Darmstadt. Herstellung: Lasertype GmbH, Holzhofallee 19 64295 Darmstadt Vertrieb: Institut TU Darmstadt Franziska-Braun-Straße 7 64287 Darmstadt. Telefon: 06151 / 16 3648 Telefax: 06151 / 16 3739 Sustainable Transformations of Water Supply Regimes The Cuvelai-Etosha Basin in Central Northern Namibia Dem Fachbereich Bauingenieurwesen und Geodäsie der Technischen Universität Darmstadt vorgelegte Dissertation zur Erlangung des akademischen Grades des Doktors der Ingenieurwissenschaften (Dr.-Ing.) von Martin Song-il Zimmermann Diplom-Wirtschaftsingenieur geboren in Duisburg München im August 2013 D17 ii Preface The research of this thesis has mainly been carried out over a period of six years. I spent three of these six years as a scholarship holder in the postgradu- ate school (Graduiertenkolleg) “Topology of Technology” of the German Re- search Foundation (DFG). The other three years, I have worked as a researcher at the Chair of Water Supply and Groundwater Protection, Institute IWAR, at Technische Universität Darmstadt. Particular thanks are due to my doctoral su- pervisor Prof. Dipl.-Ing. Dr. nat. techn. Wilhelm Urban for the confidence placed in me as well as his advice. Furthermore, I would like to thank Prof. Dr.- Ing. Manfred Ostrowski for his willingness to act as the second supervisor. The topic of the study is closely linked to the research project “CuveWaters – Integrated Water Resources Management in the Cuvelai-Etosha Basin (Central- Northern Namibia)” which is funded by the German Ministry of Education and Research (Bundesministerium für Bildung und Forschung, BMBF). The project is led by PD Dr. Thomas Kluge from the Institute for Social-Ecological Research (ISOE) in Frankfurt am Main. Project partners are the Chair of Water Supply and Groundwater Protection as well as the Chair of Wastewater Technology of the Institute IWAR at Technische Universität Darmstadt. Namibian cooperation partners are the Desert Research Foundation of Namibia (DRFN), the Namibian Ministry of Agriculture, Water, and Forestry (MAWF), and branch offices of the GIZ (German Society for International Cooperation) and the BGR (German Federal Institute for Geosciences and Natural Resources) in Namibia. The main objectives of the research project CuveWaters are to reduce the de- pendency on the water of the Angolan-Namibian border river Kunene, to devel- op endogenous water resources, to introduce innovative and adapted tech- niques, and to examine their social as well as technological feasibility. The cen- tral idea is to test and establish a multi-resources-mix of diverse water supply and sanitation techniques. Special thanks are due to Dr. Stefan Liehr from the ISOE with whom I conducted a part of the thesis’ interviews and Dr. Steffen Niemann who has provided the fundamental idea of the CuveWaters project. Furthermore, I would like to thank a number of colleagues, friends, and family members for their reviews and advice: Dr. Thomas Schiedek, Dr.-Ing. Alexand- er Sonnenburg, Dr. Komeine Nantanga, Walter Holch, Alexander Jokisch, Summer Lo, Micha Zimmermann, Samuel Chang, Philipp Benz, Marian Brenda, Elmar Schulte-Tigges, and Jana Kaiser. In addition, a number of student assis- iii tants helped to evaluate the data: William Schreiber-Madrid, Nils Messinger, Simon Widera, and Tobias Kröger. Last but not least, thanks are due to the villagers of Epyeshona, to all inter- viewees for their time and contributions, to the German Academic Exchange Service (DAAD) for co-financing my research stay in Namibia, as well as to my family and my friends for their support throughout the past years. iv Abstract In this thesis, an interdisciplinary modelling approach for water resources man- agement and its application is presented that is able to deal with socio- technical systems that are characterised by a multiplicity of variables, interde- pendencies, and actors. The case study area is the Cuvelai -Etosha Basin, which is located in central northern Namibia. Approximately 850,000 people or 40 % of the Namibian population live in this area, which comprises only about 14 % of the country’s area. The region is characterised by high precipitation variabil- ity (50-990 mm per year), a very high evaporation rate, the lack of perennial rivers, and the salinity of the groundwater in large parts of the area. These is- sues are a challenge for the regional water supply. The water supply regime in central northern Namibia is a hybrid between a centralised large technical sys- tem and several decentralised or traditional water supply techniques (e. g. Oshanas, earth dams (Omatale), dug wells (Omuthima and Oshikweyo), rain- water harvesting). The large technical system is fed by the Namibian-Angolan border river Kunene and consists of an open canal and a pipeline scheme with a length of about 2,000 km. A growing water demand due to population growth, migration and urbanisation, as well as technical and organisational problems, illegal extractions, and vandalism will probably jeopardise the situation since the local water demand exceeds the natural resources. The main research question is how the observed socio-technical system can be transformed in a sustainable manner and which key factors enable or impede such systemic transformations. The study is based on theories and concepts of systems theory, cybernetics, technological transitions, as well as socio-technical systems. Several modelling techniques were used in order to answer the re- search question. The foundation of the model was formed by the Grounded Theory, which is a qualitative method of social empirical research. Interviews with relevant stakeholders provided a deeper insight into their problem percep- tions and world views. After the identification of relevant system variables, their interrelations and roles within the system were analysed by using the Sen- sitivity Model. In doing so, it was possible to identify outstanding variables as well as processes and to reveal potential regulators, systemic hazards, and via- bility indicators. Furthermore, cause-effect chains and feedback loops were ana- lysed, based on cybernetic approaches. These findings helped to identify regula- tion mechanisms for open and closed loop control. Finally, various water supply scenarios were simulated and then assessed and compared in terms of systemic risks and viability indicators. v The analysis showed that the water supply technique of rainwater harvesting might be the most promising niche technology that is able to initiate sustaina- ble transformation processes with desirable outcomes. Furthermore, the tech- nique of floodwater harvesting might be used in order to stabilise the system in a post-transition phase and to strengthen its resilience. Finally, capacity devel- opment measures are suggested, due to their positive impacts on a large num- ber of other system variables. In addition, major hazards and risks to the sys- tem mainly stem from precarious feedback loops that have undesirable conse- quences such as an uncontrollable build-up or collapse of processes and an un- desirable resilience which impedes any kind of development or transformation. In terms of indicators for the viability of the system, technical problems with the large-scale water supply system are said to reduce the water supply secur i- ty. Furthermore, traditional water supply techniques are said to foster livestock farming and to deteriorate the users’ health considerably. All in all, the inter- viewees’ most important contribution was highlighting the relevance of tradi- tional and decentralised water supply techniques as well as the significant role they play as a complement to the pipeline scheme. The implications of all of these findings might serve to develop policies for sustainable transformations of socio-technical systems. vi Zusammenfassung In der vorliegenden Untersuchung wird ein interdisziplinärer Modellierungsan- satz für die Bewirtschaftung von Wasserressourcen und dessen Anwendung vorgestellt, der imstande ist, sozio-technische Systeme zu erfassen, die sich durch eine Vielzahl von Variablen, Abhängigkeiten und Akteuren auszeichnen. Untersuchungsraum ist das im zentralen Norden Namibias gelegene Cuvelai- Etosha-Becken. Hier leben etwa 850.000 Menschen bzw. 40 % der namibischen Bevölkerung auf einem Gebiet, das nur ca. 14 % der Fläche des Landes umfasst. Prägend für diese Region sind eine hohe Variabilität des Niederschlags (50 bis 990 mm pro Jahr), sehr hohe Verdunstungsraten, das Fehlen ganzjähriger Oberflächengewässer sowie oftmals hohe Salzgehalte des Grundwassers, was eine Herausforderung für die regionale Wasserversorgung darstellt. Das Was- serversorgungsregime in zentralen Norden