(Luận văn) assessment of drought change and its impact on salinity intrusion and agricultural activity over mekong river delta of vietnam

VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY DOI THI LOAN ASSESSMENT OF DROUGHT CHANGE AND ITS IMPACT ON SALINITY INTRUSION AND AGRICULTURAL ACTIVITY OVER MEKONG RIVER DELTA OF VIETNAM MASTER'S THESIS VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY DOI THI LOAN ASSESSMENT OF DROUGHT CHANGE AND ITS IMPACT ON SALINITY INTRUSION AND AGRICULTURAL ACTIVITY OVER MEKONG RIVER DELTA OF VIETNAM MAJOR: CLIMATE CHANGE AND DEVELOPMENT CODE: 8900201.02QTD RESEARCH SUPERVISOR: Prof Dr Phan Van Tan Hanoi, 2022 PLEDGE I assure that this thesis is the results of my own research and has not been published The use of other research’s result and other documents must comply with regulations The citations and references to documents, books, research papers, and websites must be in the lists of references of the thesis I have read and understood the plagiarism violations I pledge with personal honor that this research result is my own and does not violate the Regulation on prevention of plagiarism in academic and scientific research activities at VNU Vietnam Japan University (Issued together with Decision No 700/QD-ĐHVN dated 30/9/2021 by the Rector of Vietnam Japan University) AUTHOR OF THE THESIS Doi Thi Loan TABLE OF CONTENTS Page PLEDGE TABLE OF CONTENT LIST OF TABLES I LIST OF FIGURES ii LIST OF ABBREVIATIONS iii ACKNOWLEDGEMENT iv CHAPTER INTRODUCTION 1.1 Drought and saline intrusion under Climate Change context in Viet Nam .1 1.2 Necessity of research 1.3 Research question and hypothesis 1.4 Objectives of the research 1.5 Matrix of learning outcomes for the master's thesis 1.6 Scope of research 1.7 Study area 1.8 Structure of the thesis 1.9 Logical framework CHAPTER LITERATURE REVIEW 11 2.1 Definition of drought 11 2.1.1 Definition of drought 11 2.1.2 Causes of drought 12 2.1.3 Types of drought 13 2.2 Drought Characteristics 14 2.3 Association among drought, and saline intrusion and agricultural activity .15 2.3.1 Association among drought, and saline intrusion and agricultural activity on a global scale 15 2.3.2 Association among drought, and saline intrusion and agricultural activity in Viet Nam 16 2.4 Assessment of drought risk 20 CHAPTER DATA AND METHOD 23 3.1 Data used 23 3.2 Drought Index 24 3.3 Pearson’s Correlation Coefficient and linear regression 26 3.4 Drought risk assessment 28 CHAPTER RESULTS AND DISCUSSION 33 4.1 Spatio-temporal variability of drought over MRD 33 4.1.1 Drought change 33 4.1.2 Drought characteristics 35 4.2 Relationship between drought and saline intrusion and agricultural activity 40 4.2.1 Relationship between drought and saline intrusion 40 4.2.2 Relationship between drought and agricultural activity 42 4.3 Drought Risk assessment 43 4.3.1 Drought Hazard Index (DHI) 43 4.3.2 Drought Exposure Index (DEI) and Drought Vulnerability Index (DVI) .45 4.3.3 Drought Risk Index (DRI) 47 4.4 Recommendation 48 CHAPTER 5: CONCLUSION 51 5.1 Conclusion 51 5.2 Limitations and outlooks 52 REFERENCES 53 APPENDIX 59 APPENDIX A: Program learning outcomes (PLOS) of MCCD 59 Appendix B: Pearson’s Correlation Coefficient Tests and linear regression 60 Appendix C: Durbin Watson Test 65 Appendix D: Result of Drought Hazard Index, Drought Exposure Index, Drought Vulnerability Index and Drought Risk Index in four stage over Soc Trang province 66 LIST OF TABLES Page Table 1.1 Questions and hypothesis Table 1.2 Matrix of learning outcomes for the master’s thesis Table 3.1 List of rainfall monitoring stations in VMRD, Viet Nam…………………23 Table 3.2 Drought classification based on SPI values 25 Table 3.3 Indicator and data souses of Components 30 Table 4.1 Number of drought events for decade (1980-2020) 34 Table 4.2.Drought frequency classify by months in VMRD (1980-2020) 35 Table 4.3 Statistic of drought severities for decades in Soc Trang province 39 Table 4.4 Drought intensities for decades in Soc Trang province 39 Table 4.5 Descriptive statistics of variables 40 Table 4.6 Result of Pearson's Correlation Coefficients and Linear regression between drought severity and area of land affected by saline intrusion 42 Table 4.7 Result of Pearson's Correlation Coefficients and Linear regression between drought severity and rice production, agriculture land area 43 Table 4.8 Drought Exposure Index (DEI) over Soc Trang Province 45 Table Drought Vulnerability Index (DVI) over Soc Trang Province 46 i LIST OF FIGURES Page Figure 1.1.Vietnamese Mekong River Delta base map Figure 1.2 Average temperature in VMRD………………………………………9 Figure 1.3 Average precipitation in VMRD .9 Figure 1.4 Logical frame work of the research 10 Figure 2.1.The general sequence for the occurrence of different drought types…14 Figure 4.1 Standardized Precipitation index (SPI-6 months) (1980-2020)………33 Figure 4.2 Drought frequency in VMRD (1980-2020) 36 Figure 4.3 Drought Severity, Duration and Intensity in VMRD (1980-2020) 37 Figure 4.4 Correlation coefficients between drought severity and area of land affected by salinity a 4g/l; b.8g/l; c 12g/l 41 Figure 4.5 Correlation coefficients a Drought severity and rice production; b Drought severity and agriculture land area 42 Figure 4.6 Drought Hazard Index map over Soc Trang province .44 Figure 4.7 Drought Risk Index map over Soc Trang province 47 ii LIST OF ABBREVIATIONS CC DRGP FAO GHG GIZ GSO IPCC MONRE VMRD RCP RRD SLR SPI SSP WB WMO Climate Change Gross Regional Domestic Product Food and Agriculture Organization Greenhouse Gas Deutsche Gesellschaft für Internationale Zusammenarbeit (English: German Corporation for International Cooperation GmbH) General Statistics Office Intergovernmental Panel on Climate Change Ministry of Natural Resources and Environment Vietnamese Mekong River Delta Representative Concentration Pathways Red River Delta Sea Lever Rise Standardized Precipitation Index Shared Socio-Economic Pathways World Bank World Meteorological Organization iii ACKNOWLEDGEMENT First, I would like to express my gratitude to my supervisor, Prof Phan Van Tan, for giving me helpful guidance, support, encourage and suggestions and for welcoming all of my questions and concern all the time In addition, I would like to express my gratitude to Assoc Prof Nguyen Tien Giang, faculty of Meteorology, Hydrology and Oceanography (HMO), VNU University of Sciences (HUS), VNU for giving me suggestion, helpful guidance about expertise and academic I would also like to thank Mr Nguyen Manh Hong, Hydro-meteorological Center of the Southern Region, and Dr Dang Dinh Kha, HMO, HUS, VNU, who took the time to help me in the data collecting process I am grateful to Assoc Prof Dr Makoto Tamura, Dr Nguyen Van Quang, MSc Bui Thi Hoa, MSc Bui Thi Lan and other lecturers, staffs of Vietnam Japan University (VJU), and Ibaraki University for their contribution towards my exciting journey in VJU Last but not least, I would like to thank my friends in VJU, and my family, those who treated me, encourages me so well I appreciate your role in helping me iv CHAPTER INTRODUCTION 1.1 Drought and saline intrusion under Climate Change context in Viet Nam Climate change (CC) is arguably the most challenging issue for all humanity at the present time With rising temperatures, sea level rise (SLR), drought, flooding, saltwater intrusion…, CC poses as a major threat to the agriculture, major industries and socio-economic systems of many countries around the world (MONRE, 2011a) According to the Intergovernmental Panel on Climate Change (IPCC), by the end of the st 21 century, average temperature will increase by 2.1℃ to 3.5℃ (SSP2-4.5) on a global scale, while sea level will increase by 0.44m - 0.76m (SSP2-4.5) or as much as 0.63m - 1.01m under the very high GHG emissions scenario (SSP5-8.5) (IPCC, 2021) st In Vietnam, as shown by RCP 4.5 scenario (IPCC, 2021) by the end of the 21 century, the average temperature will increase between 1.9℃ and 2.4℃ in the North, between 1.7℃ and 1.9℃ in the South Sea level will rise 57cm - 73cm Global warming has driven an increase in the intensity of natural disasters (storms, floods, drought, SLR) According to Nguyen and co-author (2021), drought is protected increase duration, severity and intensity in dry season and transition months between the dry and wet seasons in Red River Delta, North Central, South Central In particular, drought risk could increase in sub-region, Red River Delta and South Central (Nguyen , et al., 2021) Drought tends to increase, fluctuates strongly in space and differences between climate regions (Phan , et al., 2013) Phan (2010) used statistical methods to assess the variation of drought for climatic sub-regions in Vietnam The results showed that drought tends to increase, but with uneven severity across sub-regions The frequency of drought is strongest in the North Central and South Central sub-regions, and weakest in the Northwest sub-region (Phan , 2010) In particular, the North and South Central experienced greatest frequency, severity and intensity of drought (Phan , et al., 2019) Temperature increase, shortage water and sea level rise are cause increasing area of saline intrusion in the coastal area of Red River Delta (RRD), Mekong River Delta