Multi-Scale Assessment of Risks to Environmental Hazards in Coastal Area of Bangladesh
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Multi-Scale Assessment of Risks to Environmental Hazards in Coastal Area of Bangladesh by Momtaz Jahan MASTER OF SCIENCE IN WATER RESOURCES DEVELOPMENT INSTITUTE OF WATER AND FLOOD MANAGEMENT BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY December, 2018 Multi-Scale Assessment of Risks to Environmental Hazards in Coastal Area of Bangladesh A thesis submitted by Momtaz Jahan Student ID: 1014282024 Session: October 2014 In partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN WATER RESOURCES DEVELOPMENT INSTITUTE OF WATER AND FLOOD MANAGEMENT BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY December, 2018 ii BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY INSTITUTE OF WATER AND FLOOD MANAGEMENT The thesis titled “Multi-Scale Assessment of Risks to Environmental Hazards in Coastal Area of Bangladesh” submitted by Momtaz Jahan, Student ID: 1014282024 F, Session: October, 2014 has been accepted as satisfactory in partial fulfillment of the requirement for the degree of Master of Science in Water Resources Development on 17 December, 2018. BOARD OF EXAMINERS .................................................. Dr. Mashfiqus Salehin Chairman Professor (Supervisor) Institute of Water and Flood Management Bangladesh University of Engineering and Technology, Dhaka ................................................. Dr. Sujit Kumar Bala Member Professor and Director (Ex-officio) Institute of Water and Flood Management Bangladesh University of Engineering and Technology, Dhaka ................................................ Dr. Md. Rezaur Rahman Member Professor Institute of Water and Flood Management Bangladesh University of Engineering and Technology, Dhaka ................................................. Dr. Mohammad Anisul Haque Member Professor Institute of Water and Flood Management Bangladesh University of Engineering and Technology, Dhaka ................................................. Mr. Malik Fida Abdullah Khan, M.Sc. Member Deputy Executive Director (Operation) (External) Center for Environment and Geographic Information Service (CEGIS) House 6, Road 23/C, Gulshan-1, Dhaka iii CANDIDATE’S DECLARATION It is hereby declared that this thesis or any part of it has not been submitted elsewhere for the award of any degree or diploma. .......................................... Momtaz Jahan Student ID: 1014282024 Session: October, 2014 iv Dedicated to MY BELOVED FAMILY v ACKNOWLEDGEMENT All the gratitude to the Almighty Allah who has provided me with the opportunity to complete this research successfully. I would like to take this opportunity to thank my honorable supervisor Dr. Mashfiqus Salehin, Professor, Institute of Water and Flood Management (IWFM), Bangladesh University of Engineering and Technology (BUET), for his supervision, advice, guidance and meticulous suggestion in preparing this thesis paper. He was always there to guide me with his knowledge, whether it is academic topic or nothing to do with my research; I will always be indebted to him for that. I would like to thank Dr. Md. Munsur Rahman, Professor, IWFM, BUET and Principal Investigator of the ‘DEltas, vulnerability and Climate Change: Migration and Adaptation (DECCMA) project’ for his guidance. I am grateful to him for providing me the opportunity to work in the project as an MSc Fellow. My gratitude lies towards Dr. Mohammad Anisul Haque, Professor, IWFM, BUET, for supervising me in Work Package 2 (WP2) under DECCMA project. I am also thankful to DECCMA project for the financial support it provided to carry out this research. I am thankful to the officials and staffs of Jagrata Juba Shangha (JJS) for helping me during field investigation. I express my profound respect to all my respected teachers at IWFM, BUET for their fruitful advices in different times and valuable teaching materials under different courses that have helped me to enrich my academic knowledge. I acknowledge the kind cooperation I received from the staffs of IWFM and DECCMA project. I would like to thank all my friends, colleagues and mentors at IWFM, BUET for their help me at different stages of my thesis. Many thanks go in particular to the members of WP2 for their support and MD Arif Chowdhury, Research Assistant of DECCMA project for helping me during field investigation. Finally, special thanks to my family, my biggest strength. Last but not the least, I am thankful to my little boy Tanveer for his great patience and support who always inspires me by asking “Mimmi, when will you complete your exam?”. Momtaz Jahan December, 2018 vi ABSTRACT The coastal zone of Bangladesh is highly vulnerable to extreme climate and environmental hazards. The severity or consequences of hazard depends on its nature along with the exposure of human and natural systems and vulnerability. Vulnerability and risk assessments help devise proper risk management plans focusing on reducing or modifying components of risks. But vulnerability and risk assessment needs to be carried out at appropriate scale as the components of risk vary with scale. The objective of this study was to conduct coastal risk and vulnerability assessment for three different scales: regional scale (coastal zone excluding Chittagong and Cox’s Bazar districts), sub-regional scale (Koyra upazila, Khulna district) and local scale (Bagali union, Koyra upazila). Central to the methodology was the use of IPCC AR5 approach, which defines ‘risk’ as an outcome of the interaction between ‘hazards’, ‘exposure’ and ‘vulnerability’. Respective indicators were selected based on secondary literature, expert opinion, data availability and local stakeholders’ opinion. Relative importance of indicators and domains were determined by Principal Component Analysis (PCA) for regional scale analysis. Analytical Hierarchy Process (AHP) was used for smaller scale analyses. Multi-scale assessment allows stakeholder derived and weighted parameters, which are more relevant at the local scale. For example, Sundarbans dependent livelihood and early warning system were identified as more relevant by local stakeholders. Also, regional assessment tends to mask important local scale processes, which are captured by local scale assessment. For example, Koyra upazila was found to have almost zero erosion at regional scale, whereas it is the biggest concern in all unions of the upazila. This has considerable policy implications in the context of prioritizing investments for hazard mitigation. Variations in weights against indicators and vulnerability domains were found across different scales, as local peoples’ perceptions captured in AHP differed from PCA derived weights. For example, education domain was ranked first (weightage 0.1990) at the regional scale whereas housing and infrastructure was ranked first at the sub-regional and local scales (weightage 0.3368). Similarly, livelihood domain received much higher weightage (ranked third with weightage value 0.1351) at the smaller scales because of the very high livelihood dependency on agriculture and Sundarbans dependent activities. In contrast, livelihood was ranked bottom at the regional scale (weightage 0.0213). These have implication in that investment at the local scale ought to have also major focus on housing and infrastructure improvement and livelihood improvement. The scale of assessment can determine the outcome; an area can be regarded as highly vulnerable at one scale, but differently at another scale, and an area with moderate multi- hazard value at one scale may have different multi-hazard value at another scale. For example, in Koyra upazila, multi-hazard, exposure and vulnerability values are 38.39, 24.35 and 66.51 respectively in regional scale of analysis while the same are 63.126, 44.495 and 52.884 in sub-regional scale assessment, respectively. The high multi-hazard value in Koyra is because of better representation of hazards and use of stakeholder derived weightage at the smaller scales. Hence, investments would also receive priority at the local scale for Koyra in terms of hazard mitigation. In summary, the results highlight the value of a nested approach to index development and reinforces the importance of scale in determining policy response to vulnerability. The regional scale indices could be used in regional development planning in the context of reduction of risk components. At the local level, the detail of the indices makes it possible to identify specific investments/ interventions. The indices at the three scales may allow users to make tradeoffs appropriate to their needs by choosing the most suitable index scale and thus try to ensure better utilization of resources. vii TABLE OF CONTENTS Acknowledgement .......................................................................................................... vi Abstract…...................................................................................................................... vii Table of Contents ......................................................................................................... viii List of Tables .................................................................................................................. xi List of Figures................................................................................................................ xii Abbreviations and Acronyms ...................................................................................... xv CHAPTER ONE: INTRODUCTION ........................................................................... 1 1.1