Modelling Informal Settlement Growth in Dar Es Salaam, Tanzania
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MODELLING INFORMAL SETTLEMENT GROWTH in Dar es Salaam, Tanzania FIKRESELASSIE KASSAHUN ABEBE March, 2011 SUPERVISORS: Dr. Johannes Flacke Dr. Richard Sliuzas MODELLING INFORMAL SETTLEMENT GROWTH in Dar es Salaam, Tanzania FIKRESELASSIE KASSAHUN ABEBE Enschede, The Netherlands, March, 2011 Thesis submitted to the Faculty of Geo-Information Science and Earth Observation of the University of Twente in partial fulfilment of the requirements for the degree of Master of Science in Geo-information Science and Earth Observation. Specialization: Urban Planning and Management SUPERVISORS: Dr. Johannes Flacke Dr. Richard Sliuzas THESIS ASSESSMENT BOARD: Prof. Dr. Ir. M.F.A.M. van Maarseveen (Chair) MSc. Ms. Olena Dubovyk (External Examiner, University of Bonn) Dr. Johannes Flacke (1st Supervisor) Dr. Richard Sliuzas (2nd Supervisor) DISCLAIMER This document describes work undertaken as part of a programme of study at the Faculty of Geo-Information Science and Earth Observation of the University of Twente. All views and opinions expressed therein remain the sole responsibility of the author, and do not necessarily represent those of the Faculty. ABSTRACT Dar es Salaam has witnessed rapid urbanization abreast many challenges that informal settlements have become inevitable manifestation of it. Although these settlements are known for relentless growth - leapfrogging into the unplanned periphery, very little is known about the driving forces for their sustained expansion and densification. Investigation of key driving forces of informal settlement growth in the city by coupling the potentials of Geo-Information Science with logistic regression modelling technique is made. A list of probable drivers is prepared in consultation with literature and experts‟ opinion, where in parallel spatio–temporal pattern of informal settlement expansion, 1982-2002, and densification, 1992- 1998, was conducted. The probable driving forces then are set to binary and multinomial logistic regression modelling, to explain informal settlement expansion and densification, respectively. Distances to minor roads, existing informal settlements, other-urban land use and population density (all four with odds ratios <1); and proportion of informal settlements and undeveloped land in a surrounding area (both with odds ratios >1) are found to be the most influential predictors of informal settlement expansion during 1982-2002. Population density and distances to minor rivers, other-urban land use, central business district, major rivers and major roads are on the forefront in influencing the transformation of low density informal settlement to medium agglomeration. Moreover, emerging informal settlements‟ probable density class is found to be better explained by: population density, distances to other-urban land use and minor roads for low density class; distances to existing informal settlements, river valleys and major rivers for medium density class; and distances to minor roads, existing informal settlements and central business district for high density class. Evaluation and validation results indicate the models are valid, and trend extrapolation acquired future expansion and densification areas. Further comparison of predictions of informal settlements made by logistic regression and cellular automata modelling on the same study area achieved similar results; and beyond that it revealed the need to device a mechanism how policy makers can proceed with urban policies when different predictive models are at their disposal. The attained results and approaches stretched in this study can enhance the understanding towards the nature of informal settlement growth and help urban planners and policy makers for informed decision making. Key words: informal settlement; logistic regression modelling; GIS; Dar es Salaam i ACKNOWLEDGEMENTS A number of individuals and establishments contributed greatly for the commencement and seamless accomplishment of my study that culminates to this thesis. First, I would like to express my gratitude to The Netherlands Fellowship Program (Nuffic) for the generous grant offered and let me pursue my esteemed field of study. I am also highly grateful to all the lecturers and staffs in ITC whom I portray after wisdom and humility now and for the years to come. I am exceptionally indebted to my supervisors, Dr. Johannes Flacke and Dr. Richard Sliuzas, whose guidance is invaluable, whose cooperation is priceless and whose critical thinking had spurred a great momentum to get me going. I also gratefully acknowledge Dr. Ing. Christian Lindner, Dr. Ing. Alexandra Hill, Prof. Dr. Einhard Schmidt-Kallert, Dr. Eva Dick, Dr. Richard Sliuzas, Dr. Alphonce G. Kyessi, Mr. Timoth, and Mr. George Miringay for their kind participation in the questionnaire conducted from which substantial results emanate. My special thanks also goes to Mr Kalimenze for facilitating respondents from municipalities in Dar es Salaam. Were it not for Prof. Huang Bo, who had patiently helped in solving problems confronted with Change Analyst software, the results of this thesis would have not been possible as in the present state. Once again, I would like to thank Dr. Ing. Christian Lindner for sharing predicted land use data which really gave a new insight to the study. My warmest thanks must also go to fellow UPM students who are all seemingly born to set any space alive; that is why I always presume you are all destined to be urban space planners. I would like also to direct my heartfelt respect and deep appreciation to friends, and to my families for their unparalleled encouragement and support throughout my study. Finally, my love and gratitude to Messi and Adonai who pay the most sacrifice of my long absence from home. ii TABLE OF CONTENTS List of figures ................................................................................................................................................................ iv List of tables ................................................................................................................................................................... v List of acronym ............................................................................................................................................................. vi 1. Introduction ........................................................................................................................................................... 1 1.1. Background and justification .....................................................................................................................................1 1.2. Research problem ........................................................................................................................................................3 1.3. Research objectives and questions ...........................................................................................................................4 1.4. Spatial extent of the research .....................................................................................................................................4 1.5. Conceptual framework ...............................................................................................................................................5 1.6. Research design and outline of the thesis contents ...............................................................................................7 1.7. Thesis contents outlined in chapters ........................................................................................................................8 2. Informal urban development issues in Dar es Salaam (DSM) ................................................................... 11 2.1. Introduction .............................................................................................................................................................. 11 2.2. Urban informality ..................................................................................................................................................... 11 2.3. Urbanization and informal settlement growth in DSM ..................................................................................... 12 2.4. Spatial character of informal settlement growth ................................................................................................. 22 2.5. Problems and issues associated with ISG ............................................................................................................ 24 2.6. Urban planning practice in Dar es Salaam ........................................................................................................... 28 2.7. Modelling urban growth (Land use change modelling) ..................................................................................... 32 2.8. Previous researches on informal settlement growth in Dar es Salaam ........................................................... 33 3. Data and methodology ...................................................................................................................................... 35 3.1. Introduction .............................................................................................................................................................. 35 3.2. Data source and qualities ........................................................................................................................................ 35 3.3. Identifying probable driving