Cost benefit analysis of grey and green infrastructures to adapt to sea level rise in the mekong river delta

VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY PHAM THI OANH COST–BENEFIT ANALYSIS OF MIXING GREY AND GREEN INFRASTRUCTURES TO ADAPT TO SEA LEVEL RISE IN MEKONG RIVER DELTA MASTER’S THESIS Hanoi, 2020 VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY PHAM THI OANH COST–BENEFIT ANALYSIS OF GREY AND GREEN INFRASTRUCTURES TO ADAPT TO SEA LEVEL RISE IN  MEKONG RIVER DELTA MAJOR: CLIMATE CHANGE AND DEVELOPMENT CODE: 8900201.02QTD RESEARCH SUPERVISOR: Associate Prof. MAKOTO TAMURA Dr. NGUYEN VAN QUANG Hanoi, 2020 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 list of references of the thesis.  AUTHOR OF THE THESIS PHAM THI OANH TABLE OF CONTENT TABLE OF CONTENTS ii LIST OF TABLE iv LIST OF FIGURE v LIST OF ABBREVIATIONS vi ACKNOWLEDGMENT .vii CHAPTER 1. INTRODUCTION 1.1 The necessary of the research 1.2 The research questions and hypotheses 1.2.1. The questions of research 1.2.2. The hypotheses of research 1.3. Research objectives and tasks 1.3.1. Research objectives .2 1.3.2. Research tasks .3 1.4. Scope of the research 1.5. Research Methods 1.6. Framework of the Master’s thesis .5 1.7. Overview of research in Vietnam and international 1.7.1. Climate change and climate change impact 1.7.2. SLR and SLR impact in the 21st century 1.7.3. Adaptation strategies .8 1.7.4. Model assess the SLR impact and adaptation effectiveness 12 1.7.5. MRD natural condition 14 1.7.6. SLR impact in MRD .15 1.7.7. Adaptation strategies in MRD .17 1.7.8. Research gap .18 CHAPTER 2. METHODOLOGY 20 2.1. The history of CBA and reasons for CBA 20 2.2 Outline the methodology .22 2.3 Cost­benefit analysis model 22 2.4 Data .27 2.4.1. Inundation data 30 2.4.2. Socio­Economic Scenarios 31 2.4.3. MRD data 32 2.5 Estimate costs of adaptation options 32 2.6 Estimate benefits of adaptation options 33 2.6.1. Estimate the economic damage of dryland loss can be avoid 33 2.6.2. Potential affected population by SLR 34 2.7 Applying ArcGIS software 34 2.7.1. Data preparation 34 2.7.2. Data analysis .35 CHAPTER 3. RESULTS 37 3.1. Socio­economic damage of SLR without adaptation 37 3.1.1. Identify the inundation area 37 3.1.2. Population at risk from SLR 39 3.1.3. The economic damage without adaptation 41 3.2 The economic loss in the different adaptation scenarios 44 3.2.1. The potential inundation area with adaptation 44 3.2.2. The economic damage with adaptation .46 3.3 Cost of adaptation options .46 3.4 Cost benefit analysis of mixing grey and green infrastructure .49 3.5 Comparison of mixing grey and green infrastructure with other adaptation option .50 3.6. Sensitivity analysis 53 3.6.1. Change in discount rate .53 3.6.2. Change in width of the mangrove belt 54 CHAPTER 4. DISSCUSSION AND RECOMMENDATION .56 4.1. Summary 56 4.2. Limitation of the research and future work .58 4.3. Recommendation 59 CHAPTER 5. CONCLUSION 61 5.1. Impact of SLR on the Mekong Delta region 61 5.2. Solutions to adapt to SLR .61 REFERENCES 63 APPENDIX 67 LIST OF TABLE Table 2.1: Cost and benefit of adaptation solution to reduce the damages due to  inundation by SLR in MRD, Vietnam 26 Table 2.3: Data sources and description 29 Table 3.1: The unit cost of land use by SSP1­5 .44 Table 3.2: Unit cost of adaptation options using dikes and mangrove in 2010  (million US$/m) 50 Table 3.3: Present value of the cost and benefit in different option (discount rate =  3%) 53 Table 3.4: Change in NPV and BCR in with discount rate = 8% 56 Table 3.5: Change in NPV and BCR with discount rate = 10% 56 Table 3.5: Present value of the cost and benefit with the change in the mangrove  width (discount rate = 3%) 57 LIST OF FIGURE Figure 1.1. Structure of the research Figure 2.1: Analytical framework of research .24 Figure 2.2: Cost­benefit analysis model 25 Figure 2.3: The potential inundated area in MRD by SLR in 2100 .32 Figure 2.4: World population and GDP in different SSP scenarios (Source: IIASA,  2018) 34 Figure 3.1: The potentially inundated area by land use in MRD in the 2020, 2050,  2100 respectively 39 Figure 3.2: Potentially inundated area due to SLR in MRD in the 21st century .39 Figure 3.3: Land use of potentially inundated areas due to SLR in 2100 in MRD .40 Figure 3.4: The potentially inundated by districts in MRD 41 in 2020, 2050, 2100 respectively 41 Figure 3.5: Total population at risk from SLR in MRD in 21st century 42 Figure 3.6: Economic losses due to SLR in MRD in the 21st century 46 Figure 3.7: Comparison of land use loss due to SLR in MRD with and without  adaptation solution (km2/year) .47 Figure 3.8: The damage cost of SLR with different adaptation option (no discount  rate) .48 Figure 3.9: Net present value and Benefit cost ratio of mixing grey and green  infrastructure 51 Figure 3.10: Cost contribution of mixing grey and green infrastructure 52 Figure 3.11: Cost of adaptation options under SSP1­5 without discount rate 53 Figure 3.12:  BCR in different adaptation options under SSP1­5 55 Figure 4.1. The urgency of coastal protection .62 LIST OF ABBREVIATIONS BCR: Benefit Cost Ratio CBA: Cost Benefit Analysis CPMD: Coastal Protection for the Mekong Delta IPCC: Inter­governmental Panel on Climate Change MRD: Mekong River Delta MONRE: Ministry of Nature Resources and Environment  NPV: Net Present Value RCP: Representative Concentration Pathway SSP: Share Socio­economic Pathway ACKNOWLEDGMENT I would like to express my respecting to Assoc Prof Makoto Tamura who introduced me to this exciting topic and supervising me during this time My thanks also go to Dr Nguyen Van Quang for his comments during this thesis work Their comment and essential enabled me to complete this study on time My warm thanks also go to members of the Master of Climate Change and Development office for their relentless supporting during this time Finally, my grateful acknowledgment to my friends and family for their recommendations, suggestions and supportive of my study in VJU 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 17.22 18.69 20.16 21.63 23.88 26.13 28.38 30.63 32.89 35.71 38.54 41.37 44.20 47.03 49.77 52.52 55.27 58.02 60.77 63.08 65.40 67.72 70.04 72.35 74.26 76.17 78.08 79.99 81.90 83.53 85.16 86.79 88.42 90.05 14.23 14.04 13.77 13.43 13.48 13.41 13.24 12.99 12.68 12.52 12.28 11.98 11.64 11.26 10.83 10.39 9.94 9.49 9.03 8.52 8.03 7.56 7.11 6.68 6.23 5.81 5.41 5.04 4.69 4.35 4.03 3.74 3.46 3.20 17.19 18.65 20.10 21.56 23.70 25.85 27.99 30.14 32.28 34.81 37.34 39.87 42.40 44.93 47.20 49.47 51.74 54.01 56.28 58.07 59.86 61.65 63.44 65.23 66.64 68.05 69.46 70.88 72.29 73.49 74.69 75.89 77.10 78.30 14.21 14.01 13.73 13.39 13.38 13.26 13.06 12.78 12.45 12.20 11.90 11.55 11.17 10.76 10.27 9.79 9.31 8.83 8.37 7.85 7.35 6.89 6.44 6.02 5.59 5.19 4.82 4.47 4.14 3.83 3.54 3.27 3.02 2.79 17.17 18.62 20.06 21.51 23.59 25.67 27.75 29.83 31.92 34.27 36.63 38.98 41.34 43.69 45.64 47.58 49.52 51.46 53.41 54.76 56.11 57.46 58.81 60.16 61.05 61.94 62.83 63.72 64.61 65.25 65.88 66.52 67.15 67.79 157 14.19 13.99 13.70 13.35 13.31 13.17 12.95 12.65 12.30 12.01 11.67 11.29 10.89 10.46 9.93 9.41 8.91 8.41 7.94 7.40 6.89 6.42 5.97 5.55 5.12 4.72 4.36 4.02 3.70 3.40 3.12 2.86 2.63 2.41 17.18 18.63 20.09 21.54 23.62 25.70 27.78 29.86 31.94 34.26 36.57 38.89 41.20 43.52 45.37 47.23 49.08 50.94 52.79 54.02 55.25 56.47 57.70 58.93 59.73 60.53 61.33 62.13 62.94 63.52 64.11 64.70 65.29 65.87 14.20 14.00 13.72 13.37 13.33 13.19 12.96 12.66 12.32 12.01 11.65 11.26 10.85 10.42 9.87 9.34 8.83 8.33 7.85 7.30 6.79 6.31 5.86 5.44 5.01 4.62 4.25 3.92 3.61 3.31 3.04 2.79 2.56 2.34 17.23 18.71 20.18 21.66 23.97 26.27 28.58 30.88 33.19 36.19 39.20 42.20 45.21 48.21 51.31 54.41 57.51 60.61 63.71 66.56 69.41 72.25 75.10 77.95 80.54 83.12 85.70 88.29 90.87 93.28 95.68 98.08 100.49 102.89 14.24 14.05 13.79 13.45 13.53 13.48 13.33 13.10 12.80 12.69 12.49 12.22 11.90 11.54 11.17 10.76 10.34 9.91 9.47 8.99 8.53 8.07 7.62 7.19 6.76 6.34 5.94 5.57 5.21 4.86 4.53 4.22 3.93 3.66 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 92.26 94.47 96.67 98.88 101.09 103.92 106.76 109.59 112.43 115.26 118.49 121.73 124.96 128.19 131.42 134.56 137.69 140.83 143.96 147.10 149.93 152.76 155.60 158.43 161.26 166.89 172.52 178.15 183.78 189.41 192.63 195.84 199.06 202.28 2.98 2.78 2.58 2.40 2.23 2.09 1.95 1.82 1.70 1.58 1.48 1.38 1.29 1.20 1.12 1.04 0.97 0.90 0.84 0.78 0.72 0.67 0.62 0.57 0.53 0.50 0.47 0.44 0.41 0.39 0.36 0.33 0.30 0.28 79.63 80.97 82.30 83.64 84.97 86.49 88.01 89.53 91.05 92.57 94.26 95.95 97.63 99.32 101.01 103.25 105.49 107.72 109.96 112.20 114.87 117.54 120.22 122.89 125.56 131.18 136.80 142.42 148.04 153.66 156.28 158.89 161.51 164.13 2.58 2.38 2.20 2.03 1.88 1.74 1.61 1.49 1.37 1.27 1.18 1.09 1.01 0.93 0.86 0.80 0.74 0.69 0.64 0.59 0.55 0.51 0.48 0.44 0.41 0.39 0.37 0.35 0.33 0.31 0.29 0.27 0.25 0.23 68.48 69.16 69.85 70.53 71.22 72.04 72.85 73.67 74.48 75.30 76.20 77.10 78.00 78.90 79.80 80.78 81.76 82.74 83.72 84.70 85.67 86.64 87.61 88.58 89.56 91.21 92.87 94.52 96.18 97.83 98.54 99.25 99.95 100.66 158 2.22 2.03 1.87 1.71 1.57 1.45 1.33 1.22 1.12 1.03 0.95 0.87 0.80 0.74 0.68 0.63 0.58 0.53 0.49 0.45 0.41 0.38 0.35 0.32 0.29 0.27 0.25 0.23 0.22 0.20 0.18 0.17 0.15 0.14 66.56 67.25 67.93 68.62 69.31 70.14 70.98 71.81 72.65 73.48 74.41 75.35 76.28 77.21 78.14 79.16 80.19 81.21 82.23 83.25 84.28 85.31 86.34 87.37 88.40 90.20 92.00 93.80 95.60 97.41 98.22 99.03 99.84 100.65 2.15 1.98 1.82 1.67 1.53 1.41 1.30 1.19 1.10 1.01 0.93 0.85 0.79 0.72 0.67 0.61 0.56 0.52 0.48 0.44 0.41 0.37 0.34 0.32 0.29 0.27 0.25 0.23 0.21 0.20 0.18 0.17 0.15 0.14 106.08 109.27 112.45 115.64 118.83 122.89 126.94 131.00 135.06 139.12 143.79 148.46 153.13 157.80 162.47 167.41 172.36 177.31 182.26 187.20 192.57 197.94 203.31 208.68 214.05 226.64 239.24 251.84 264.44 277.04 284.39 291.74 299.09 306.44 3.43 3.21 3.01 2.81 2.63 2.47 2.32 2.17 2.04 1.91 1.79 1.68 1.58 1.48 1.38 1.30 1.21 1.13 1.06 0.99 0.93 0.87 0.81 0.75 0.70 0.68 0.65 0.62 0.59 0.56 0.53 0.49 0.46 0.43 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 Total 205.50 205.50 205.50 205.50 205.50 205.50 209.05 212.59 216.14 219.68 223.23 226.95 230.67 234.39 238.12 241.84 245.77 249.70 253.63 257.56 261.50 0.26 0.24 0.22 0.20 0.18 0.16 0.15 0.14 0.13 0.12 0.11 0.10 0.09 0.09 0.08 0.07 0.07 0.06 0.06 0.05 0.05 385.43 166.75 166.75 166.75 166.75 166.75 166.75 169.38 172.02 174.65 177.29 179.92 182.71 185.49 188.28 191.06 193.85 196.85 199.86 202.86 205.87 208.87 0.21 0.19 0.17 0.16 0.14 0.13 0.12 0.11 0.10 0.10 0.09 0.08 0.07 0.07 0.06 0.06 0.05 0.05 0.05 0.04 0.04 362.55 101.37 101.37 101.37 101.37 101.37 101.37 102.09 102.82 103.54 104.27 104.99 105.79 106.58 107.37 108.17 108.96 109.84 110.72 111.61 112.49 113.37 0.13 0.12 0.11 0.10 0.09 0.08 0.07 0.07 0.06 0.06 0.05 0.05 0.04 0.04 0.04 0.03 0.03 0.03 0.03 0.02 0.02 344.79 101.46 101.46 101.46 101.46 101.46 101.46 102.31 103.15 103.99 104.83 105.68 106.59 107.51 108.43 109.35 110.26 111.23 112.20 113.16 114.13 115.09 0.13 0.12 0.11 0.10 0.09 0.08 0.07 0.07 0.06 0.06 0.05 0.05 0.04 0.04 0.04 0.03 0.03 0.03 0.03 0.02 0.02 342.39 313.78 313.78 313.78 313.78 313.78 313.78 321.82 329.85 337.89 345.92 353.96 362.47 370.97 379.48 387.98 396.49 405.55 414.61 423.66 432.72 441.78 0.40 0.36 0.33 0.30 0.27 0.25 0.23 0.21 0.20 0.19 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.10 0.10 0.09 0.08 407.06 Table 3: Afforestation of green infrastructure Unit:Million USD Mixing grey and green SSP1 SSP2 SSP3 SSP4 SSP5 Cost PV Cost PV Cost PV Cost PV Cost PV 2010 378.00 378.00 378.00 378.00 378.00 378.00 378.00 378.00 378.00 378.00 2020 Year 159 2030 2040 2050 2060 2070 2080 2090 2100 Total 2435.16 20.74 398.74 1871.66 15.94 1478.67 393.94 12.60 390.60 1447.95 12.33 390.33 3010.40 25.64 403.64 Table 4: Maintenance cost of green infrastructure Unit:Million USD Year 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020-2059 2060 2061 2062 2063 SSP1 Cost PV 349.65 349.65 385.62 350.56 421.59 348.42 457.56 343.77 493.53 337.09 529.50 328.78 584.65 330.02 639.80 328.32 694.95 324.20 750.10 318.11 0.00 0.00 3217.89 27.41 3294.66 25.51 3371.42 23.74 3448.19 22.07 Mixing grey and green SSP2 SSP3 SSP4 Cost PV Cost PV Cost PV 349.65 349.65 349.65 349.65 349.65 349.65 385.28 350.26 385.03 350.03 385.19 350.17 420.92 347.87 420.42 347.45 420.73 347.71 456.55 343.02 455.80 342.45 456.27 342.80 492.19 336.17 491.18 335.49 491.80 335.91 527.82 327.74 526.57 326.96 527.34 327.44 580.34 327.58 577.55 326.01 578.31 326.44 632.85 324.75 628.52 322.53 629.28 322.92 685.36 319.73 679.50 316.99 680.25 317.34 737.87 312.93 730.48 309.79 731.21 310.11 0.00 0.00 0.00 0.00 0.00 0.00 2473.26 21.07 1953.96 16.64 1913.36 16.30 2528.06 19.58 1977.93 15.32 1938.37 15.01 2582.85 18.18 2001.89 14.09 1963.38 13.82 2637.65 16.88 2025.86 12.97 1988.38 12.73 160 SSP5 Cost PV 349.65 349.65 385.78 350.71 421.92 348.69 458.05 344.14 494.18 337.53 530.32 329.29 586.79 331.23 643.27 330.10 699.74 326.44 756.22 320.71 0.00 0.00 3978.02 33.89 4099.16 31.74 4220.30 29.71 4341.44 27.79 2064 2065 2066 2067 2068 2069 2070-2100 Total 3524.96 3601.72 3671.08 3740.45 3809.81 3879.17 0.00 20.51 19.05 17.65 16.35 15.14 14.01 0.00 3358.92 2692.44 2747.23 2812.67 2878.11 2943.55 3008.99 0.00 15.67 14.53 13.52 12.58 11.70 10.87 0.00 3339.69 2049.82 2073.79 2097.59 2121.39 2145.18 2168.98 0.00 11.93 10.97 10.09 9.27 8.52 7.84 0.00 3327.35 2013.39 2038.39 2063.63 2088.88 2114.12 2139.36 0.00 11.71 10.78 9.92 9.13 8.40 7.73 0.00 3330.48 4462.58 4583.71 4715.17 4846.62 4978.07 5109.52 0.00 25.96 24.24 22.67 21.19 19.78 18.46 0.00 3368.49 Table 5: Benefit of green infrastructure Unit: Million USD Year 2010-2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 SSP1 Cost PV 0.00 0.00 213.28 82.23 231.62 81.18 249.96 79.65 268.30 77.72 286.64 75.48 304.98 73.01 322.80 70.25 340.62 67.39 358.44 64.47 376.26 61.52 394.08 58.58 409.11 55.28 424.14 52.10 439.17 49.05 454.21 46.11 Mixing grey and green SSP2 SSP3 SSP4 SSP5 Cost PV Cost PV Cost PV Cost PV 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 209.35 80.71 206.98 79.80 207.17 79.87 215.25 82.99 225.76 79.13 222.26 77.90 222.19 77.87 234.73 82.27 242.17 77.16 237.53 75.69 237.20 75.58 254.21 81.00 258.59 74.90 252.81 73.23 252.21 73.06 273.69 79.28 275.00 72.42 268.09 70.60 267.22 70.37 293.17 77.20 291.41 69.76 283.37 67.84 282.24 67.57 312.65 74.85 306.13 66.62 295.96 64.41 294.26 64.04 332.75 72.42 320.85 63.48 308.56 61.05 306.28 60.60 352.86 69.81 335.56 60.35 321.16 57.76 318.31 57.25 372.97 67.08 350.28 57.27 333.76 54.57 330.33 54.01 393.08 64.27 365.00 54.25 346.36 51.48 342.35 50.89 413.18 61.42 376.61 50.89 355.11 47.99 350.32 47.34 431.65 58.33 388.22 47.69 363.87 44.70 358.28 44.01 450.12 55.30 399.83 44.65 372.62 41.61 366.25 40.90 468.59 52.33 411.44 41.77 381.38 38.72 374.22 37.99 487.06 49.45 161 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060-2069 2070 2071 2072 2073 2074 2075 2076 2077 469.24 481.63 494.01 506.40 518.79 531.18 541.74 552.31 562.88 573.44 584.01 598.33 612.64 626.96 641.28 655.60 673.98 692.37 710.75 729.13 747.52 768.47 789.43 810.39 831.35 0.00 1045.83 1082.33 1118.84 1155.34 1191.85 1228.36 1249.23 1270.11 43.31 40.41 37.68 35.12 32.70 30.44 28.22 26.16 24.24 22.45 20.78 19.36 18.02 16.76 15.59 14.49 13.54 12.64 11.80 11.00 10.26 9.58 8.95 8.35 7.79 0.00 3.43 3.23 3.04 2.85 2.67 2.50 2.32 2.14 423.05 432.20 441.35 450.50 459.65 468.80 476.60 484.40 492.20 500.00 507.80 516.45 525.11 533.77 542.42 551.08 560.93 570.79 580.64 590.49 600.35 611.29 622.24 633.19 644.13 0.00 814.31 850.75 887.19 923.64 960.08 996.52 1013.50 1030.47 39.05 36.26 33.67 31.24 28.98 26.87 24.83 22.94 21.19 19.57 18.07 16.71 15.44 14.27 13.18 12.18 11.27 10.42 9.64 8.91 8.24 7.62 7.06 6.53 6.04 0.00 2.67 2.54 2.41 2.28 2.15 2.03 1.88 1.74 390.14 395.92 401.70 407.48 413.26 419.05 423.16 427.28 431.40 435.52 439.63 444.08 448.53 452.98 457.43 461.88 467.17 472.46 477.75 483.04 488.34 494.18 500.02 505.86 511.70 0.00 580.79 591.53 602.26 613.00 623.73 634.47 639.05 643.64 162 36.01 33.22 30.64 28.26 26.05 24.01 22.05 20.24 18.57 17.05 15.64 14.37 13.19 12.11 11.12 10.21 9.38 8.63 7.93 7.29 6.70 6.16 5.67 5.21 4.79 0.00 1.91 1.77 1.63 1.51 1.40 1.29 1.18 1.08 382.18 387.38 392.57 397.77 402.96 408.16 411.97 415.78 419.59 423.40 427.21 431.66 436.11 440.56 445.01 449.46 454.88 460.29 465.71 471.12 476.54 482.59 488.64 494.69 500.73 0.00 573.33 585.00 596.68 608.35 620.03 631.70 636.97 642.23 35.27 32.50 29.94 27.58 25.40 23.39 21.46 19.69 18.07 16.57 15.20 13.96 12.83 11.78 10.82 9.93 9.14 8.41 7.73 7.11 6.54 6.02 5.54 5.10 4.69 0.00 1.88 1.75 1.62 1.50 1.39 1.29 1.18 1.08 505.53 522.29 539.06 555.82 572.58 589.34 604.93 620.52 636.10 651.69 667.28 687.95 708.62 729.29 749.97 770.64 796.95 823.26 849.58 875.89 902.21 932.49 962.78 993.07 1023.35 0.00 1388.15 1469.86 1551.57 1633.28 1714.98 1796.69 1844.35 1892.01 46.66 43.82 41.12 38.54 36.09 33.77 31.52 29.39 27.39 25.51 23.74 22.25 20.84 19.50 18.23 17.03 16.01 15.03 14.10 13.22 12.38 11.63 10.92 10.24 9.59 0.00 4.56 4.39 4.21 4.03 3.85 3.66 3.42 3.19 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 1290.99 1311.86 1332.74 1332.74 1332.74 1332.74 1332.74 1332.74 1355.73 1378.72 1401.71 1424.70 1447.69 1471.83 1495.97 1520.11 1544.25 1568.39 1593.89 1619.38 1644.88 1670.38 1695.88 Total 1.98 1.83 1.69 1.53 1.39 1.27 1.15 1.05 0.97 0.90 0.83 0.77 0.71 0.65 0.60 0.56 0.51 0.48 0.44 0.41 0.37 0.35 0.32 1556.59 1047.45 1064.42 1081.40 1081.40 1081.40 1081.40 1081.40 1081.40 1098.49 1115.58 1132.67 1149.76 1166.85 1184.91 1202.97 1221.03 1239.10 1257.16 1276.64 1296.13 1315.62 1335.10 1354.59 1.60 1.48 1.37 1.24 1.13 1.03 0.94 0.85 0.79 0.72 0.67 0.62 0.57 0.53 0.49 0.45 0.41 0.38 0.35 0.32 0.30 0.28 0.25 1425.71 648.22 652.80 657.39 657.39 657.39 657.39 657.39 657.39 662.09 666.79 671.49 676.20 680.90 686.05 691.20 696.36 701.51 706.66 712.37 718.08 723.79 729.50 735.21 0.99 0.91 0.83 0.76 0.69 0.63 0.57 0.52 0.47 0.43 0.40 0.36 0.33 0.30 0.28 0.26 0.23 0.21 0.20 0.18 0.16 0.15 0.14 1323.64 647.50 652.76 658.03 658.03 658.03 658.03 658.03 658.03 663.49 668.95 674.42 679.88 685.35 691.30 697.25 703.20 709.15 715.10 721.36 727.63 733.89 740.15 746.42 0.99 0.91 0.83 0.76 0.69 0.63 0.57 0.52 0.47 0.43 0.40 0.37 0.33 0.31 0.28 0.26 0.24 0.22 0.20 0.18 0.17 0.15 0.14 1307.76 1939.67 1987.33 2034.99 2034.99 2034.99 2034.99 2034.99 2034.99 2087.10 2139.20 2191.31 2243.42 2295.53 2350.69 2405.86 2461.02 2516.19 2571.35 2630.10 2688.84 2747.59 2806.33 2865.08 2.97 2.77 2.58 2.34 2.13 1.94 1.76 1.60 1.49 1.39 1.29 1.20 1.12 1.04 0.97 0.90 0.84 0.78 0.72 0.67 0.63 0.58 0.54 1680.08 Table 6: Benefit of avoiding SLR damage Unit: Billion USD Year SSP1 Benefit PV SSP2 Benefit PV Mixing grey and green SSP3 SSP4 Benefit PV Benefit PV 163 SSP5 Benefit PV 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 0.00 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 134.25 134.25 134.25 134.25 134.25 134.25 134.25 134.25 134.25 134.25 77.50 77.50 77.50 77.50 77.50 77.50 77.50 77.50 77.50 77.50 78.63 78.63 78.63 0.00 88.34 80.31 73.01 66.37 60.34 54.85 49.87 45.33 41.21 37.47 47.05 42.77 38.89 35.35 32.14 29.22 26.56 24.15 21.95 19.95 10.47 9.52 8.66 7.87 7.15 6.50 5.91 5.37 4.89 4.44 4.10 3.72 3.39 0.00 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 121.20 121.20 121.20 121.20 121.20 121.20 121.20 121.20 121.20 121.20 59.78 59.78 59.78 59.78 59.78 59.78 59.78 59.78 59.78 59.78 53.74 53.74 53.74 0.00 88.34 80.31 73.01 66.37 60.34 54.85 49.87 45.33 41.21 37.47 42.48 38.62 35.11 31.91 29.01 26.38 23.98 21.80 19.82 18.02 8.08 7.34 6.68 6.07 5.52 5.02 4.56 4.15 3.77 3.43 2.80 2.55 2.31 0.00 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 112.41 112.41 112.41 112.41 112.41 112.41 112.41 112.41 112.41 112.41 42.34 42.34 42.34 42.34 42.34 42.34 42.34 42.34 42.34 42.34 29.42 29.42 29.42 164 0.00 88.34 80.31 73.01 66.37 60.34 54.85 49.87 45.33 41.21 37.47 39.40 35.82 32.56 29.60 26.91 24.46 22.24 20.22 18.38 16.71 5.72 5.20 4.73 4.30 3.91 3.55 3.23 2.94 2.67 2.43 1.53 1.39 1.27 0.00 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 109.80 109.80 109.80 109.80 109.80 109.80 109.80 109.80 109.80 109.80 38.30 38.30 38.30 38.30 38.30 38.30 38.30 38.30 38.30 38.30 28.26 28.26 28.26 0.00 88.34 80.31 73.01 66.37 60.34 54.85 49.87 45.33 41.21 37.47 38.48 34.98 31.80 28.91 26.28 23.90 21.72 19.75 17.95 16.32 5.17 4.70 4.28 3.89 3.53 3.21 2.92 2.66 2.41 2.19 1.47 1.34 1.22 0.00 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 97.17 143.24 143.24 143.24 143.24 143.24 143.24 143.24 143.24 143.24 143.24 98.67 98.67 98.67 98.67 98.67 98.67 98.67 98.67 98.67 98.67 112.30 112.30 112.30 0.00 88.34 80.31 73.01 66.37 60.34 54.85 49.87 45.33 41.21 37.47 50.20 45.64 41.49 37.72 34.29 31.17 28.34 25.76 23.42 21.29 13.33 12.12 11.02 10.02 9.11 8.28 7.53 6.84 6.22 5.65 5.85 5.32 4.84 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 78.63 78.63 78.63 78.63 78.63 78.63 78.63 116.28 116.28 116.28 116.28 116.28 116.28 116.28 116.28 116.28 116.28 118.43 118.43 118.43 118.43 118.43 118.43 118.43 118.43 118.43 118.43 109.55 109.55 109.55 109.55 109.55 109.55 109.55 3.08 2.80 2.54 2.31 2.10 1.91 1.74 2.34 2.12 1.93 1.75 1.60 1.45 1.32 1.20 1.09 0.99 0.92 0.83 0.76 0.69 0.63 0.57 0.52 0.47 0.43 0.39 0.33 0.30 0.27 0.25 0.22 0.20 0.18 53.74 53.74 53.74 53.74 53.74 53.74 53.74 62.63 62.63 62.63 62.63 62.63 62.63 62.63 62.63 62.63 62.63 99.09 99.09 99.09 99.09 99.09 99.09 99.09 99.09 99.09 99.09 111.24 111.24 111.24 111.24 111.24 111.24 111.24 2.10 1.91 1.74 1.58 1.44 1.31 1.19 1.26 1.14 1.04 0.95 0.86 0.78 0.71 0.65 0.59 0.53 0.77 0.70 0.63 0.58 0.52 0.48 0.43 0.39 0.36 0.33 0.33 0.30 0.27 0.25 0.23 0.21 0.19 29.42 29.42 29.42 29.42 29.42 29.42 29.42 33.90 33.90 33.90 33.90 33.90 33.90 33.90 33.90 33.90 33.90 40.84 40.84 40.84 40.84 40.84 40.84 40.84 40.84 40.84 40.84 33.41 33.41 33.41 33.41 33.41 33.41 33.41 165 1.15 1.05 0.95 0.87 0.79 0.71 0.65 0.68 0.62 0.56 0.51 0.47 0.42 0.38 0.35 0.32 0.29 0.32 0.29 0.26 0.24 0.22 0.20 0.18 0.16 0.15 0.13 0.10 0.09 0.08 0.07 0.07 0.06 0.06 28.26 28.26 28.26 28.26 28.26 28.26 28.26 34.88 34.88 34.88 34.88 34.88 34.88 34.88 34.88 34.88 34.88 42.77 42.77 42.77 42.77 42.77 42.77 42.77 42.77 42.77 42.77 36.26 36.26 36.26 36.26 36.26 36.26 36.26 1.11 1.01 0.91 0.83 0.76 0.69 0.62 0.70 0.64 0.58 0.53 0.48 0.44 0.40 0.36 0.33 0.30 0.33 0.30 0.27 0.25 0.23 0.21 0.19 0.17 0.15 0.14 0.11 0.10 0.09 0.08 0.07 0.07 0.06 112.30 112.30 112.30 112.30 112.30 112.30 112.30 165.76 165.76 165.76 165.76 165.76 165.76 165.76 165.76 165.76 165.76 201.24 201.24 201.24 201.24 201.24 201.24 201.24 201.24 201.24 201.24 242.22 242.22 242.22 242.22 242.22 242.22 242.22 4.40 4.00 3.63 3.30 3.00 2.73 2.48 3.33 3.03 2.75 2.50 2.27 2.07 1.88 1.71 1.55 1.41 1.56 1.42 1.29 1.17 1.06 0.97 0.88 0.80 0.73 0.66 0.72 0.66 0.60 0.54 0.49 0.45 0.41 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100   Total 109.55 109.55 137.46 137.46 137.46 137.46 137.46 137.46 137.46 137.46 137.46 137.46 150.68 150.68 150.68 150.68 150.68 150.68 150.68 150.68 150.68 150.68 150.68 0.17 0.15 0.17 0.16 0.14 0.13 0.12 0.11 0.10 0.09 0.08 0.07 0.07 0.07 0.06 0.06 0.05 0.05 0.04 0.04 0.03 0.03 0.03 1039.36 111.24 111.24 108.95 108.95 108.95 108.95 108.95 108.95 108.95 108.95 108.95 108.95 116.19 116.19 116.19 116.19 116.19 116.19 116.19 116.19 116.19 116.19 116.19 0.17 0.15 0.14 0.13 0.11 0.10 0.09 0.09 0.08 0.07 0.06 0.06 0.06 0.05 0.05 0.04 0.04 0.04 0.03 0.03 0.03 0.02 0.02 974.87 33.41 33.41 31.79 31.79 31.79 31.79 31.79 31.79 31.79 31.79 31.79 31.79 34.35 34.35 34.35 34.35 34.35 34.35 34.35 34.35 34.35 34.35 34.35 0.05 0.05 0.04 0.04 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 920.19 36.26 36.26 36.21 36.21 36.21 36.21 36.21 36.21 36.21 36.21 36.21 36.21 38.50 38.50 38.50 38.50 38.50 38.50 38.50 38.50 38.50 38.50 38.50 0.06 0.05 0.05 0.04 0.04 0.03 0.03 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 910.24 242.22 242.22 305.13 305.13 305.13 305.13 305.13 305.13 305.13 305.13 305.13 305.13 341.62 341.62 341.62 341.62 341.62 341.62 341.62 341.62 341.62 341.62 341.62 0.37 0.34 0.39 0.35 0.32 0.29 0.26 0.24 0.22 0.20 0.18 0.16 0.17 0.15 0.14 0.13 0.11 0.10 0.09 0.09 0.08 0.07 0.06 1107.52 Section 5: Sensitivity analysis, mangrove width = 350 meters, discount rate = 3% Table 1: Afforestation cost of mangrove forest Unit: Million USD Year Mixing grey and green 166 SSP1 SSP2 SSP3 SSP4 SSP5 Cost PV Cost PV Cost PV Cost PV Cost PV 2010 264.60 264.60 264.60 264.60 264.60 264.60 264.60 264.60 264.60 264.60 2020 2030 2040 2050 2060 2435.16 555.48 1871.66 426.94 1478.67 337.30 1447.95 330.29 3010.40 686.69 2070 2080 2090 2100 Total 820.08 691.54 601.90 594.89 951.29 Table 2: Maintenance cost of mangrove forest Unit: Million USD Year 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020-2059 2060 2061 Mixing grey and green SSP1 SSP2 SSP3 SSP4 SSP5 Cost PV Cost PV Cost PV Cost PV Cost PV 255.15 255.15 255.15 255.15 255.15 255.15 255.15 255.15 255.15 255.15 281.40 273.20 281.15 272.96 280.97 272.79 281.08 272.90 281.52 273.32 307.65 289.99 307.16 289.53 306.79 289.18 307.02 289.39 307.89 290.21 333.90 305.56 333.16 304.89 332.61 304.39 332.95 304.70 334.25 305.89 360.14 319.98 359.16 319.11 358.43 318.46 358.88 318.86 360.62 320.41 386.39 333.31 385.17 332.25 384.25 331.46 384.82 331.95 386.99 333.82 426.64 357.30 423.49 354.66 421.45 352.96 422.01 353.43 428.20 358.61 466.88 379.62 461.81 375.49 458.65 372.93 459.20 373.37 469.41 381.67 507.12 400.33 500.13 394.81 495.85 391.43 496.40 391.86 510.62 403.09 547.37 419.51 538.45 412.68 533.05 408.54 533.59 408.95 551.83 422.94 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2348.19 535.64 1804.81 411.69 1425.86 325.25 1396.24 318.49 2902.88 662.17 2404.21 532.44 1844.80 408.56 1443.35 319.65 1414.49 313.26 2991.28 662.46 167 2062 2063 2064 2065 2066 2067 2068 2069 2070-2100 Total 2460.23 2516.25 2572.26 2628.28 2678.90 2729.52 2780.13 2830.75 0.00 528.98 525.27 521.32 517.16 511.77 506.25 500.62 494.89 0.00 8508.28 1884.78 1924.77 1964.75 2004.74 2052.49 2100.24 2147.99 2195.75 0.00 405.25 401.80 398.20 394.47 392.10 389.54 386.79 383.87 0.00 7283.78 1460.84 1478.33 1495.82 1513.30 1530.67 1548.04 1565.40 1582.77 0.00 314.10 308.60 303.16 297.77 292.41 287.12 281.88 276.71 0.00 6303.93 1432.73 1450.98 1469.23 1487.48 1505.90 1524.31 1542.73 1561.15 0.00 308.06 302.89 297.77 292.69 287.68 282.72 277.80 272.93 0.00 6254.84 3079.68 3168.08 3256.47 3344.87 3440.80 3536.72 3632.64 3728.57 0.00 662.17 661.34 659.99 658.16 657.32 655.96 654.13 651.85 0.00 9930.65 Table 3: Benefit of mangrove forest Unit: Million USD Year 2010-2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 SSP1 Cost PV 0.00 0.00 147.99 110.12 160.72 116.11 173.44 121.65 186.17 126.77 198.90 131.49 211.62 135.83 223.99 139.58 236.35 143.00 248.71 146.09 261.08 148.89 273.44 151.40 283.87 152.60 294.30 153.59 Mixing grey and green SSP2 SSP3 SSP4 SSP5 Cost PV Cost PV Cost PV Cost PV 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 145.26 108.09 143.62 106.87 143.75 106.97 149.36 111.14 156.65 113.17 154.22 111.41 154.17 111.38 162.88 117.66 168.04 117.86 164.82 115.60 164.59 115.44 176.39 123.72 179.43 122.18 175.42 119.45 175.00 119.17 189.91 129.32 190.82 126.15 186.02 122.98 185.42 122.59 203.42 134.49 202.20 129.79 196.62 126.20 195.84 125.70 216.94 139.25 212.42 132.37 205.36 127.98 204.18 127.24 230.89 143.88 222.63 134.69 214.10 129.54 212.52 128.58 244.84 148.13 232.84 136.77 222.85 130.90 220.87 129.74 258.79 152.01 243.05 138.61 231.59 132.07 229.21 130.71 272.75 155.54 253.26 140.23 240.33 133.06 237.55 131.53 286.70 158.74 261.32 140.47 246.40 132.45 243.08 130.67 299.51 161.00 269.38 140.59 252.48 131.77 248.61 129.75 312.33 163.00 168 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060-2069 2070 2071 2072 2073 2074 2075 304.73 315.16 325.59 334.19 342.78 351.38 359.98 368.57 375.90 383.24 390.57 397.90 405.23 415.17 425.10 435.04 444.97 454.91 467.66 480.42 493.17 505.93 518.69 533.23 547.77 562.31 576.85 0.00 725.68 751.01 776.34 801.67 827.00 852.33 154.41 155.04 155.51 154.96 154.32 153.58 152.75 151.85 150.36 148.82 147.25 145.65 144.01 143.25 142.40 141.48 140.50 139.45 139.19 138.82 138.36 137.80 137.16 136.90 136.54 136.08 135.53 0.00 123.17 123.76 124.21 124.52 124.72 124.79 277.43 285.49 293.54 299.89 306.24 312.59 318.94 325.29 330.70 336.11 341.52 346.94 352.35 358.36 364.36 370.37 376.38 382.38 389.22 396.06 402.89 409.73 416.57 424.16 431.76 439.35 446.95 0.00 565.03 590.32 615.60 640.89 666.18 691.46 140.57 140.44 140.20 139.06 137.87 136.63 135.34 134.01 132.28 130.52 128.76 126.99 125.22 123.64 122.06 120.45 118.84 117.22 115.84 114.44 113.03 111.60 110.16 108.90 107.62 106.32 105.01 0.00 95.90 97.28 98.49 99.55 100.46 101.24 258.55 264.63 270.71 274.72 278.73 282.74 286.75 290.77 293.62 296.48 299.34 302.19 305.05 308.14 311.23 314.31 317.40 320.49 324.16 327.83 331.50 335.17 338.85 342.90 346.95 351.00 355.05 0.00 403.00 410.45 417.90 425.35 432.79 440.24 169 131.01 130.18 129.29 127.39 125.48 123.58 121.68 119.79 117.45 115.13 112.86 110.62 108.41 106.32 104.26 102.22 100.22 98.25 96.48 94.73 93.00 91.29 89.60 88.03 86.48 84.94 83.42 0.00 68.40 67.64 66.86 66.07 65.27 64.46 254.13 259.66 265.19 268.79 272.40 276.00 279.61 283.21 285.86 288.50 291.14 293.79 296.43 299.52 302.61 305.70 308.78 311.87 315.63 319.39 323.15 326.90 330.66 334.86 339.05 343.25 347.45 0.00 397.82 405.92 414.02 422.12 430.22 438.32 128.77 127.74 126.65 124.64 122.63 120.63 118.65 116.68 114.34 112.04 109.77 107.54 105.35 103.34 101.37 99.42 97.50 95.61 93.94 92.29 90.66 89.04 87.44 85.97 84.51 83.07 81.63 0.00 67.52 66.89 66.24 65.57 64.88 64.18 325.15 337.96 350.78 362.41 374.04 385.67 397.30 408.93 419.75 430.56 441.38 452.19 463.01 477.35 491.70 506.04 520.38 534.73 552.99 571.25 589.50 607.76 626.02 647.04 668.05 689.07 710.08 0.00 963.20 1019.90 1076.60 1133.29 1189.99 1246.69 164.75 166.26 167.53 168.05 168.39 168.57 168.59 168.47 167.89 167.20 166.41 165.52 164.55 164.70 164.71 164.58 164.31 163.92 164.58 165.07 165.38 165.54 165.54 166.12 166.52 166.75 166.83 0.00 163.49 168.07 172.24 176.03 179.46 182.53 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 Total 866.81 881.30 895.79 910.27 924.76 924.76 924.76 924.76 924.76 924.76 940.71 956.66 972.62 988.57 1004.52 1021.27 1038.02 1054.77 1071.52 1088.27 1105.96 1123.65 1141.35 1159.04 1176.73 123.22 121.63 120.03 118.41 116.79 113.39 110.09 106.88 103.77 100.75 99.50 98.24 96.97 95.69 94.40 93.18 91.95 90.71 89.47 88.22 87.04 85.86 84.67 83.48 82.29 8930.90 703.24 715.02 726.80 738.58 750.36 750.36 750.36 750.36 750.36 750.36 762.22 774.08 785.93 797.79 809.65 822.18 834.72 847.25 859.78 872.31 885.83 899.36 912.88 926.40 939.92 99.97 98.68 97.38 96.08 94.77 92.01 89.33 86.73 84.20 81.75 80.62 79.49 78.36 77.22 76.09 75.02 73.94 72.87 71.79 70.71 69.72 68.72 67.72 66.72 65.73 7632.53 443.42 446.60 449.78 452.96 456.15 456.15 456.15 456.15 456.15 456.15 459.41 462.67 465.93 469.20 472.46 476.04 479.61 483.19 486.76 490.34 494.30 498.26 502.22 506.19 510.15 170 63.03 61.64 60.27 58.92 57.61 55.93 54.30 52.72 51.19 49.69 48.59 47.51 46.45 45.42 44.40 43.43 42.49 41.56 40.64 39.75 38.90 38.07 37.26 36.46 35.67 6103.00 441.98 445.63 449.28 452.94 456.59 456.59 456.59 456.59 456.59 456.59 460.38 464.17 467.96 471.75 475.55 479.68 483.80 487.93 492.06 496.19 500.54 504.88 509.23 513.58 517.92 62.83 61.50 60.20 58.92 57.67 55.99 54.36 52.77 51.24 49.74 48.70 47.67 46.66 45.66 44.69 43.77 42.86 41.96 41.09 40.22 39.39 38.58 37.78 36.99 36.22 6023.36 1279.75 1312.82 1345.89 1378.96 1412.03 1412.03 1412.03 1412.03 1412.03 1412.03 1448.19 1484.35 1520.50 1556.66 1592.82 1631.09 1669.37 1707.65 1745.92 1784.20 1824.96 1865.73 1906.49 1947.25 1988.01 181.92 181.18 180.33 179.38 178.34 173.14 168.10 163.20 158.45 153.83 153.18 152.43 151.59 150.68 149.69 148.82 147.88 146.86 145.78 144.64 143.63 142.56 141.44 140.25 139.02 11282.78 ... In? ?general? ?the? ?research tries? ?to? ?assess? ?the? ?impact? ?of? ?SLR? ?in? ?MRD aiming? ?to calculate? ?the? ?effectiveness? ?of? ?the? ?grey? ?and? ?green? ?infrastructures.   On? ?the? ?other hand, to? ?confirm? ?the? ?effectiveness? ?of? ?mixing? ?grey? ?and? ?green? ?infrastructures, ? ?the? ?research... Carry out evaluation? ?and? ?estimation? ?of? ?damage caused by SLR by identifying the? ?economic? ?and? ?social impacts? ?of? ?SLR? ?to? ?the? ?Mekong? ?Delta? ?region ­ Assess? ?the? ?costs? ?of? ?mixing? ?grey? ?and? ?green? ?infrastructure? ?to? ?adapt? ?to? ?SLR? ?in MRD ­ Cost   benefit   analysis: ... not apply forecasts for longer time periods due? ?to? ?the? ?volatility? ?and? ?uncertainty of? ?the? ?above factors ­ Regarding? ?the? ?scope? ?of? ?space:? ?The? ?scope? ?of? ?the? ?research space? ?of? ?the? ?topic is? ?the region   of   the   Mekong   Delta   of   Vietnam,