Evaluation of water stress and water quality under the impact of climate change in the upper thai binh river basin, vietnam

VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY HTET THU SOE EVALUATION OF WATER STRESS AND WATER QUALITY UNDER THE IMPACT OF CLIMATE CHANGE IN THE UPPER THAI BINH RIVER BASIN, VIETNAM MASTER’S THESIS     VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY HTET THU SOE EVALUATION OF WATER STRESS AND WATER QUALITY UNDER THE IMPACT OF CLIMATE CHANGE IN THE UPPER THAI BINH RIVER BASIN, VIETNAM MAJOR: ENVIRONMENTAL ENGINEERING CODE: 8520320.01 RESEARCH SUPERVISORS: Associate Prof Dr SATO KEISUKE Dr PHAM QUY GIANG Hanoi, 2021     ACKNOWLEDGEMENTS Firstly, I would like to acknowledge Japan-ASEAN Integration Fund Scholarship Program Because of this scholarship, I got the opportunity to study Master’s Program in VNU Vietnam – Japan University, Vietnam I also thank the academic authority for their effort to provide a continuous learning environment even in this global pandemic I would like to express my deepest gratitude to my principal supervisor, Associate Professor Dr Sato Keisuke His research motivation, supervision and unique approaches to each dimension played a critical role to raise these successful research outcomes I will never forget his kindness and gratitude in my life I also would like to thank my cosupervisor, Dr Pham Quy Giang who unwaveringly supported me to collect necessary research data, including provision of research idea and encouragement My appreciation also extends to Ms Pham Thi Kieu Chinh who assisted me to complete research works I could not have been completed without her kind supports I am also grateful to Assistant Professor Dr Taishi Yazawa, for his invaluable research advices I also would like to thank every single member of Master’s Program in Environmental Engineering for their kind supports during these two years, from enrollment to graduation Finally, yet importantly, my gratitude goes to my parents and soulmate who always respect my decisions, and they had acted as my rock in times of troubles Their encouragement had been the crux of this research journey This research was financially supported by JICA Research Grant Program, Ritsumeikan University and the Ministry of Education, Culture, Sports, Science and Technology-MEXT/the Japan Society for the Promotion of Science-JSPS KAKENHI Grant Program (JP 18H04153) Thanks All!!     TABLE OF CONTENTS   CHAPTER 1: INTRODUCTION 1.1 General Background 1.2 Research Motivation 1.3 Target Basin 1.4 Problem Statements 1.5 Objectives 1.6 Thesis Structure 1.7 Baseline Information about the Study Basin 1.7.1 Hydrological Features 1.7.2 Topography and Administrative Boundaries 1.7.3 Climatic Condition 1.8 Summary 10 CHAPTER 2: LITERATURE REVIEW 11 2.1 Administrative Provinces 11 2.2 Hydrological Modelling 12 2.3 Climate Change 13 2.4 Water Stress Assessment 15 2.5 Water Quality Evaluation 17 2.6 Summary 20 CHAPTER 3: HYDROLOGICAL SIMULATION 21 3.1 SWAT Hydrological Model 21 3.1.1 Preparation of In-put Data for Model Set-up 23 3.2 SWAT Model Set-up 29 3.2.1 Watershed Delineation 29 3.2.2 HRU Analysis 29 3.2.3 Integration with Weather Database 29 3.3 SWAT Model Calibration and Validation 30 3.4 Model Performance Evaluation 30 3.5 Results of Simulation 31 3.5.1 SWAT Model Calibration and Validation Result 31 3.6 Summary 35 CHAPTER 4: CLIMATE PROJECTION 36 4.1 Future Climate Scenario 36 4.2 Performance Analysis of Bias Correction Method 38 4.3 Results of Climate Projection 39 4.3.1 Performance Evaluation 39     4.3.2 Projected Precipitation Data 39 4.3.3 Projected Maximum and Minimum Temperature 41 4.4 Summary 45 CHAPTER 5: WATER STRESS ASSESSMENT 46 5.1 Water Demand 46 5.2 Water Resources 46 5.3 Water Stress 46 5.4 Future Water Stress 47 5.5 Result of Water Stress Assessment 48 5.5.1 Current Water Demand 48 5.5.2 Current Water Resource Potential 49 5.5.3 Current Water Stress 49 5.5.4 Future Water Demand 50 5.5.5 Future Water Resource Potential 51 5.5.6 Future Water Stress 51 5.6 Summary 53 CHAPTER 6: WATER QUALITY EVALUATION .54 6.1 Water Quality Parameters 55 6.2 Vietnamese National Water Quality Index (VN_WQI) 56 6.2.1 Calculating WQI in this Study 56 6.3 Data Analysis 57 6.4 Result of Water Quality Assessment 58 6.4.1 Water Quality Results 58 6.4.2 Results of Statistical Analysis 62 6.4.3 Results of Water Quality Index 85 6.5 Future Water Quality Status under the Impact of Climate Change 88 6.6 Summary 89 CHAPTER 7: CONCLUSION, LMITATATIONS AND FUTURE TREND .90 REFERENCES 92 APPENDICES 99 Appendix Result of Population Projection 99 Appendix 2.A Detailed Statistics About Current Water Stress 100 Appendix 2.B Detailed Statistics About Future Water Stress 101 Appendix Photo Records of River Water Sampling Point 102 Appendix Scenes During River Water Sampling 105 Appendix List of Survey Team Member 105 Appendix Analytical Methods 106 Appendix Detailed WQI Calculation Method 110     LIST OF TABLES Table 2.1 Variation of Precipitation (%) during 1958 – 2014 .14 Table 3.1 SWAT Land Use Code and Statistics (2015) 26 Table 3.2 Summary for Preparation of Model Input-Data 28 Table 3.3 Model Performance Rating 31 Table 3.4 Goodness-of-fit Statistics for Discharge Simulation 32 Table 3.5 Calibrated Parameters and Fitted Values 32 Table 3.6 Average Monthly Hydrological Components 34 Table 3.7 Annual Water Balance Statistics 34 Table 4.1 Description of RCM 36 Table 4.2 Period of Study and Projected Climatic Variables 36 Table 4.3 Performance Evaluation Results 39 Table 4.4 Changes in Seasonal Precipitation .40 Table 4.5 Changes in Seasonal Maximum Temperature .42 Table 4.6 Changes in Seasonal Minimum Temperature 42 Table 4.7 Changes in Long Term Annual Temperature 43 Table 6.1 Location of River Water Sampling Points 54 Table 6.2 Summary of Water Quality Parameters .56 Table 6.3 VN_WQI Based Classification for Surface Water Quality 57 Table 6.4 In-situ Water Quality Result of Cau River Sub-basin 58 Table 6.5 Ex-situ Water Quality Result of Cau River Sub-basin 59 Table 6.6 In-situ Water Quality Result of Luc Nam River Sub-basin 60 Table 6.7 Ex-situ Water Quality Result of Luc Nam River Sub-basin .60 Table 6.8 In-situ Water Quality Result of Thuong River Sub-basin 61 Table 6.9 Ex-situ Water Quality Result of Thuong River Sub-basin 61 Table 6.10 Mean Values of Water Quality Parameters observed in CRSB 62 Table 6.11 Mean Values of Water Quality Parameters observed in LNRSB 63 Table 6.12 Mean Values of Water Quality Parameters observed in TRSB 63 Table 6.13 Correlation Matrix .66 Table 6.14 Total Variance Explained for Wet Season of CRSB 67 Table 6.15 PCA Loadings (CRSB-Wet Season) 68 Table 6.16 Total Variance Explained for Dry Season of CRSB 70 Table 6.17 PCA Loadings (CRSB-Dry Season) 71 Table 6.18 Total Variance Explained for Wet Season of LNRSB 73 Table 6.19 PCA Loadings (LNSB-Wet Season) 74 Table 6.20 Total Variance Explained for Dry Season of LNRSB .76 Table 6.21 PCA Loadings (LNSB-Dry Season) 77 Table 6.22 Total Variance Explained for Wet Season of TRSB 78 i   Table 6.23 PCA Loadings (TRSB-Wet Season) 79 Table 6.24 Total Variance Explained for Dry Season of TRSB 81 Table 6.25 PCA Loadings (TRSB-Dry Season) 82 ii   LIST OF FIGURES Figure 1.1 Location of Target Basin (Source: TA-7629, VIE, 2012) Figure 1.2 Long Term Annual Maximum Temperature Trend .8 Figure 1.3 Long Term Annual Minimum Temperature Trend Figure 1.4 Long Term Monthly Precipitation Trend .9 Figure 1.5 Average Monthly Discharge at the Gia Bay Hydrological Station (20052019) Figure 1.6 Work Flow of the Research 10 Figure 2.1 Annual Changes of Temperature (Ngu et al., 2016) 14 Figure 2.2 Water Stress Levels in Vietnam (2030WRG, 2017) 17 Figure 2.3 River Water Quality in Vietnam (2030WRG, 2017) 20 Figure 3.1 DEM of the UPTBRB 23 Figure 3.2 High Resolution Land Use and Land Cover Map of the UPTBRB (2015) .25 Figure 3.3 Major Land Cover Statistics in the UPTBRB 25 Figure 3.4 Soil Map of the UPTBRB 26 Figure 3.5 The Proportion of Soil Classes observed in the UPTBRB 27 Figure 3.6 Location of Hydro-meteorological Stations .28 Figure 3.7 Formation of HRUs 29 Figure 3.8 Calibration Result at the Gia Bay Hydrological Station 33 Figure 3.9 Validation Result at the Gia Bay Hydrological Station .33 Figure 3.10 Annual Water Balance of the UPTBRB (2008 – 2019) 35 Figure 4.1 Location of Projected Meteorological Stations 38 Figure 4.2 Average Monthly Precipitation Trends (5-stations average) .41 Figure 4.3 Annual Changes of Precipitation Trends (5-stations average) 41 Figure 4.4 Average Monthly Changes of Maximum Temperature (5-stations average) .43 Figure 4.5 Average Monthly Changes of Minimum Temperature (5-stations average) .44 Figure 4.6 Annual Changes of Maximum Temperature (5-stations average) .44 Figure 4.7 Annual Changes of Minimum Temperature (5-stations average) 45 Figure 5.1 Proportion of Sectoral Water Demand .49 Figure 5.2 Distribution of Current Water Stress Levels 50 Figure 5.3 Distribution of Predicted Water Stress Levels 52 Figure 5.4 Comparison of Current and Future Water Statistics (Annual) 52 Figure 5.5 Changes in Water Demand by Each Sector .53 Figure 6.1 Location Map of Sampling Points 55 Figure 6.2 Eigen Values and Proportion of Variances (CRSB-Wet Season) 68 iii   Figure 6.3 Bi-plot Illustration for PC1 and PC2 in CRSB (Wet Season) 69 Figure 6.4 Bi-plot Illustration for PC2 and PC3 in CRSB (Wet Season) 69 Figure 6.5 Bi-plot Illustration for PC1 and PC3 in CRSB (Wet Season) 70 Figure 6.6 Eigen Values and Proportion of Variances (CRSB-Dry Season) 71 Figure 6.7 Bi-plot Illustration for PC1 and PC2 in CRSB (Dry Season) 72 Figure 6.8 Bi-plot Illustration for PC2 and PC3 in CRSB (Dry Season) 72 Figure 6.9 Bi-plot Illustration for PC1 and PC3 in CRSB (Dry Season) 73 Figure 6.10 Eigen Values and Proportion of Variances (LNSB-Wet Season) 74 Figure 6.11 Bi-plot Illustration for PC1 and PC2 in LNRSB (Wet Season) .75 Figure 6.12 Bi-plot Illustration for PC2 and PC3 in LNRSB (Wet Season) .75 Figure 6.13 Bi-plot Illustration for PC1 and PC3 in LNRSB (Wet Season) .76 Figure 6.14 Eigen Values and Proportion of Variances for LNRSB (Dry Season) 76 Figure 6.15 Bi-plot Illustration for PC1 and PC2 in LNRSB (Dry Season) .77 Figure 6.16 Eigen Values and Proportion of Variances (TRSB-Wet Season) 78 Figure 6.17 Bi-plot Illustration for PC1 and PC2 in TRSB (Wet Season) 79 Figure 6.18 Bi-plot Illustration for PC2 and PC3 in TRSB (Wet Season) 80 Figure 6.19 Bi-plot Illustration for PC1 and PC3 in TRSB (Wet Season) 80 Figure 6.20 Eigen Values and Proportion of Variances (TRSB-Dry Season) 81 Figure 6.21 Bi-plot Illustration for PC1 and PC2 in TRSB (Dry Season) 82 Figure 6.22 Bi-plot Illustration for PC2 and PC3 in TRSB (Dry Season) 83 Figure 6.23 Bi-plot Illustration for PC1 and PC3 in TRSB (Dry Season) 83 Figure 6.24 Cluster Dendrogram for Wet Season in the UPTBRB .84 Figure 6.25 Cluster Dendrogram for Dry Season in UPTBRB 85 Figure 6.26 Seasonal Variation of Observed WQI in the CRSB 86 Figure 6.27 Seasonal Variation of Observed WQI in the LNRSB 87 Figure 6.28 Seasonal Variation of Observed WQI in the TRSB .88 iv   LIST OF ABBREVIATIONS CEM CMIP6 CRSB DEM LNRSB TRSB PCA RCP 4.5 RCM SWAT UPTBRB VEA WQI : : : : : : : : : : : : : Center for Environmental Monitoring Coupled Model Inter-comparison Project Phase Cau River Sub-basin Digital Elevation Model Luc Nam River Sub-basin Thuong River Sub-basin Principal Component Analysis Representative Concentration Pathway under 4.5 Scenario Regional Climate Model Soil and Water Assessment Tool Upper Thai Binh River Basin Vietnam Environmental Administration Water Quality Index                     v     Internet Sources a) https://thuvienphapluat.vn/van-ban/Tai-nguyen-Moi-truong/Quyet-dinh-1460QD-TCMT-2019-ky-thuat-tinh-toan-va-cong-bo-chi-so-chat-luong-nuoc428277.aspx b) http://vietnamlawmagazine.vn/bac-ninh-province-a-hi-tech-developmenthotspot-5761.html c) https://childfund.org.vn/bac-kan-program-area/ d) https://www.alotrip.com/about-vietnam-geography/hanoi-geography e) https://www.alotrip.com/about-vietnam-overview/thai-nguyen-overview f) http://www.vinhphuc.gov.vn/ngthongke/2003/2013/niengiam/index.htm g) https://offroadvietnam.com/vietnam-info/basic-details/bac-giang-province/ h) https://esgf-data.dkrz.de/projects/esgf-dkrz/ i) https://www.worldpop.org 98     APPENDICES Appendix Result of Population Projection Basin ID 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 2010 58197 92881 42715 27534 102144 38969 83403 74989 57928 37868 51651 45683 86916 78481 50676 65422 47406 152464 363328 408179 143446 579566 234496 982964 754186 33771 291 2020 2030 61962 65983 98890 105308 45478 48429 29316 31218 108751 115809 41490 44183 88925 91765 79840 85022 61675 65678 40317 42934 54992 58561 48638 51795 92538 98544 83558 88981 53954 57455 69654 74175 50473 53748 162326 172861 386832 411937 458808 488585 152726 162638 632279 673314 249666 265869 1052701 1121021 818977 872129 35956 38290 310 330 2040 2050 2060 70265 74825 79682 112142 119420 127171 51572 54920 58484 33244 35402 37700 123325 131329 139853 47050 50104 53355 100842 107386 114356 90540 96416 102673 69940 74479 79313 45720 48688 51847 62362 66409 70719 55156 58736 62548 104940 111750 119003 94756 100906 107454 61184 65155 69384 78989 84115 89574 57237 60951 64907 184080 196027 208749 438672 467142 497460 520294 554062 590020 173193 184433 196403 717013 763547 813101 283124 301499 321066 1193776 1271252 1353756 928730 989005 1053191 40775 43421 46239 351 374 398                 99     Appendix 2.A Detailed Statistics About Current Water Stress Water Demand Basin ID Municipal Industrial Agricultural 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 2,667,394 4,257,129 1,957,786 1,262,017 4,681,660 1,786,108 3,825,280 3,437,054 2,655,063 1,735,630 2,367,368 2,093,831 3,983,706 3,597,107 2,322,666 2,998,553 2,172,805 6,988,023 16,652,798 19,201,975 6,574,717 26,873,928 10,747,915 45,178,490 34,893,373 1,547,883 13,326 673,425 0 0 1,642,500 0 0 0 0 0 3,859,875 8,483,513 0 2,531,914 9,884,565 0 76,267,050 88,840,325 44,643,295 37,149,455 106,784,200 51,962,453 27,877,550 66,590,742 53,727,531 53,561,704 58,385,320 51,795,915 89,093,959 54,837,212 65,796,084 62,741,785 62,459,354 177,198,995 281,708,720 187,158,425 55,721,824 267,650,020 153,107,370 291,842,545 224,979,090 19,936,635 885,000 Water Total Resource Demand 78,934,444 482,359,719 93,770,879 1,361,892,270 46,601,081 355,879,665 38,411,472 478,690,771 111,465,860 414,427,653 53,748,561 261,746,426 33,345,330 97,803,201 70,027,796 700,412,130 56,382,594 519,159,425 55,297,334 443,611,994 60,752,688 372,039,380 53,889,746 411,513,344 93,077,665 363,377,596 58,434,318 225,688,174 68,118,750 799,513,973 65,740,337 964,628,264 64,632,159 337,364,858 184,187,018 821,493,140 302,221,393 1,100,257,304 214,843,912 569,324,223 62,296,541 165,044,417 294,523,948 753,420,350 163,855,285 503,940,755 339,552,949 1,048,606,556 269,757,028 697,179,781 21,484,517 85,777,322 898,326 207,706 Water Stress 0.16 0.07 0.13 0.08 0.27 0.21 0.34 0.10 0.11 0.12 0.16 0.13 0.26 0.26 0.09 0.07 0.19 0.22 0.27 0.38 0.38 0.39 0.33 0.32 0.39 0.25 4.32               100     Appendix 2.B Detailed Statistics About Future Water Stress Basin 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Sectoral Water Demand Municipal Industrial Agricultural 4,362,565 83,893,755 6,962,601 1,346,850 97,724,358 3,201,990 49,107,625 2,064,048 40,864,401 7,656,927 117,462,620 2,921,207 57,158,698 6,260,968 3,285,000 30,665,305 5,621,356 73,249,816 4,342,397 59,100,284 2,838,650 58,917,874 3,871,868 64,223,852 3,424,492 56,975,507 6,515,413 98,003,355 5,883,124 60,320,933 3,798,757 72,375,692 4,904,180 69,015,963 3,553,656 68,705,290 11,429,020 194,918,895 27,235,910 7,719,750 309,879,592 32,303,605 16,967,025 205,874,268 10,753,052 61,294,006 44,517,293 294,415,022 17,578,382 168,418,107 74,118,167 5,063,828 321,026,800 57,662,220 19,769,130 247,476,999 2,531,586 21,930,298 21,794 973,500 Total Water Water Water Demand Resource Stress 0.23 88,256,320 389,911,006 0.10 106,033,808 1,100,872,989 0.18 52,309,614 287,672,027 0.11 42,928,448 386,945,246 0.37 125,119,547 334,998,750 0.28 60,079,906 211,580,297 0.51 40,211,273 79,058,311 0.14 78,871,171 566,171,651 0.15 63,442,681 419,657,707 0.17 61,756,524 358,589,642 0.23 68,095,720 300,734,583 0.18 60,399,999 332,642,996 0.36 104,518,768 293,732,910 0.36 66,204,057 182,432,943 0.12 76,174,449 646,279,707 0.09 73,920,143 779,748,313 0.26 72,258,946 272,705,755 0.31 206,347,914 664,046,363 0.39 344,835,252 889,382,790 0.55 255,144,898 460,207,957 0.54 72,047,058 133,412,124 0.56 338,932,315 609,020,354 0.46 185,996,489 407,355,836 0.47 400,208,794 847,631,387 0.58 324,908,349 563,558,812 0.35 24,461,884 69,337,303 5.93 995,294 167,897                 101     Appendix Photo Records of River Water Sampling Point SO1: Cau River, Bac Kan S02: Cau River, Bac Kan S03: Cho Chu Tributary, Bac Kan S04: Cau River, Bac Kan S05: Thuong Nang Tributary, Bac Kan S06: Cau River, Thai Nguyen S07: Du Tributary, Thai Nguyen S08: Cau River, Thai Nguyen 102     S09: Cau River, Thai Nguyen S10: Cong Tributary, Thai Nguyen S11: Cau River, Hanoi S12: Calo Tributary, Hanoi S13: Cau River, Bac Ninh S14: Cau River, Bac Ninh S15: Rang Tributary, Lang Son S16: Thuong River, Lang Son 103     S17: Thuong River, Bac Giang S18: Dinh Dem Tributary, Son Dong S19: Luc Nam River, Bac Giang S20: Luc Nam River, Bac Giang S21: Luc Nam River, Bac Giang S22: Luc Nam River, Bac Giang S23: Thai Binh River, Pha Lai       104     Appendix Scenes During River Water Sampling Appendix List of Survey Team Member Name Dr SATO KEISUKE Title Associate Professor/JICA Expert Institution VNU Vietnam Japan University, Ritsumeikan University PHAM THI KIEU CHINH Ph.D Candidate Ritsumeikan University HTET THU SOE VNU Vietnam Japan University Master Candidate         105     Appendix Analytical Methods (a) Total Suspended Solid (TSS) i Procedure Filter papers were cleaned with 200 mL of distilled water The cleaned filter papers were kept on the dishes and dried in the oven at 103 °C for 60 minutes The weight of dried filter papers including the dishes were recorded on the balance (m1) The volume of 200 mL of the water samples were filtrated through the dried filter papers and dried again in the oven at 103 °C for 60 minutes The weight of sample filters including dishes (m2) were recorded The concentration of final TSS was calculated using the equation A6.1 TSS (mg/L) = 100 (A6.1) Where: m1 = Weight of filter and dish after cleaning with deionized water (mg) m2 = Weight of filter and dish after sample filtration (mg) V = Volume of the sample (liter) (b) Biochemical Oxygen Demand (BOD) i Reagents Preparation Four kind of solutions are prepared for BOD measurement Solution A of Phosphate buffer (pH 7.2) was prepared using  K2HPO4 21.75g, KH2PO4 8.5g, Na2HPO4.12H2O 44.6g in which 1.7 gram of NH4Cl was dissolved in liter of deionized water Solution B was prepared using 22.5 (g/l) of magnesium sulphate, MgSO4.7H2O Solution C was prepared using 27.5 (g/l) of Calcium Chloride, CaCl2 0.25 (g/l) of ferric chloride, FeCl3.H2O was used to prepare Solution D ii Preparation of Diluted Water Bubble deionized water was prepared and preserved at 20°C for more than day And then, mL from each prepared solution A, B, C and D was added to the 1-liter bottle of deionized water 106     iii Procedure The solutions were prepared by adding 100 mL of the prepared deionized water to BOD bottles And then, 20 mL of the samples were further added to these bottles The initial concentration of DO were recorded After keeping days in the incubator, the concentration of DOs was measured again and determined using equation A6.2 BOD (mg/L) = (DO0 – DO5) / P (A6.2) In which: BOD = Biochemical oxygen demand (mg/L) DO0 = Initial DO concentration (mg/L) DO5 = DO concentration after days (mg/L) P = Total volume of the solution/volume of sample (L) (c) Chemical Oxygen Demand (COD) (i) Procedure The pack test was applied to determine the concentration of COD The blank sample was prepared by adding 1.5 mL of the sample into the designated cell The solution was prepared using 25 mL of the sample and 0.5 mL of the reagent COD R-1 and well-mixed The reagent COD R-2 was then added and shake for 30 seconds again The prepared samples were measured in the pack test and recorded the results (d) Ammonium (NH4+ - N) i Reagents Preparation The procedures for preparation of reagents were described below; ‐ Hypochlorite solution: dissolve 15g of NaOH and 500 mL of NaOCl 0.1% and diluted to 1000 mL by distilled water ‐ Prepare Phenol-sodium nitroprusside solution by adding phenol (5g) together with 0.025g of nitroprusside and diluted to 500 mL by distilled water ‐ Stock ammonium solution: dissolve 3.8228g of NH4Cl in distilled water and diluted to 1000 mL (1000 mgNH4/L) and prepare standard ammonium solution mg/L: dilute from Stock nitrogen solution to 100 times 107     Figure A6.1 Reagents Preparation for Determination of Ammonium Concentration ii Procedure 5mL of the sample was added to the test tube and 3mL of Phenol-sodium nitroprusside solution was further added and well-mixed 3mL of Hypochlorite solution was added again and well-mixed The samples were boiled gently in the water bath at 30 to 40 oC for 15 minutes Using the spectrophotometer, the absorbance was measured at 640 nm and calculate the ammonium concentration from the calibration curve (e) Nitrate (NO3- - N) and Nitrite (NO2- - N) i Procedure The pack test was applied to determine the concentration of NO3- - N and NO2- N The blank sample was prepared by adding 1.5 mL of the sample into the designated cell Similarly, 1.5 mL of the sample was added to the reagent kit and shake for 30 seconds The result is recorded after minutes The maximum detective range for reading of NO3- - N by the pack test is 0.2 mg/L whereas NO2- - N is 0.01 to 0.3 mg/L (f) Phosphate (PO4- - P) i Reagents Preparation The procedures for preparation of reagents were described below; ‐ Prepare the solution of Ammonium molybdate-antimony potassium tartrate by adding 8g of ammonium molybdate together with 0.2g antimony potassium tartrate in the distilled water having 800 mL, then diluted to 1000 mL 108     ‐ Prepare the solution of Ascorbic acid by adding 60g of ascorbic acid in the distilled water having 800 mL, then diluted to 1000 mL The acetone having mL was added ‐ Sulfuric acid, 11 N: slowly added 310 mL of concentration of H2SO4 to 600 mL of distilled water Cooled and diluted to 1L ‐ Stock phosphorus solution: dissolve 4.3957g of pre-dried at 105oC for 60 mintues, KH2PO4 in distilled water and diluted to 1000 mL (1mL = mgP = 1000 mgP/l) ‐ Prepare the standard solution by diluting mL of the solution of stock phosphorus with 100 mL of deionized water and then diluted 10 mL of phosphorus solution to 100 mL followed by preparing an suitable sequence of standards by diluting appropriate ratios of stock/standard solutions to 100 mL with the deionized water (Diego, 2013) Figure A6.2 Reagents Preparation for Determination of Phosphate Concentration ii Procedure ‐ mL of 11N sulfuric acid and ammonium molybdate-antimony potassium tartrate with the volume of mL are added to the sample/ standard having 50 mL ‐ mL of ascorbic acid is further added and well-mixed ‐ After minutes, the spectrophotometer was used to measure the absorbance at 710 nm and calculate the concentration of phosphorus from the calibration curve 109     Appendix Detailed WQI Calculation Method (a) Group (I) parameter Table A7.1 Quality Index and Breaking Points for Group (I) Parameter i Bpi qi < 5.5 10 5.5 50 100 8.5 100 50 >9 10 If pH value is less than 5.5 or greater than 9, then WQI for pH is 10 If pH is greater than but less than 6, then the WQI for pH is calculated using equation A7.1 and table A7.1 If pH range is between and 8.5, then the WQI for pH is 100 If 8.50.05 Coliform MPN/100 mL 2500 5000 7500 10000 >10000 Table A7.3 Quality Index and Breaking Points for Group (b) Parameters i qi 100 75 50 25 10 BPi Value Turbidity TSS (NTU) (mg/L) 20 30 70 100 20 30 50 100 > 100 The observed water temperature at the time of field monitoring in degree Celsius was used to find out the saturation DO and the percentage of saturation DO saturation = 14.652-0.41022T+0.0079910T2-0.000077774T3 (A7.3) And then, the saturation percentage of DO was determined using the equation A6.4 DO% DO / DO ∗ 100 (A7.4) The WQI value for DO can be determined using the following equations A7.5 and A7.6 in which Cp stands for saturated percentage of DO (A7.5) (A7.6) 111     Table A7.4 Quality Index and Breaking Points for Saturated DO% i BPi qi 200 100 100 75 50 25 10 If the saturated DO% is < 20 or saturated DO% > 200, then WQIDO is equal to 10 If 20 < saturation DO value < 88, WQIDO is calculated according to equation A7.1 and table A7.4 If 88 saturation% DO value 112, then WQIDO is equal to 100 If 112 < saturation DO value < 200, WQIDO is calculated according to equation A7.2 and use table A7.4 If the value of saturation DO% is 200 and then WQIDO is equal to 10       112   .. .VIETNAM NATIONAL UNIVERSITY, HANOI VIETNAM JAPAN UNIVERSITY HTET THU SOE EVALUATION OF WATER STRESS AND WATER QUALITY UNDER THE IMPACT OF CLIMATE CHANGE IN THE UPPER THAI BINH RIVER BASIN, VIETNAM. .. Target basin of the study is Upper Thai Binh River Basin (UPTBRB) located in the Northern Vietnam The UPTBRB is a component of Red -Thai Binh River Basin that occupied almost the entire area of North... originated in outside of the country; China, Cambodia, Lao PDR and Thailand (MONRE, 2006 & 2030WRG, 2017) Mekong and Red -Thai Binh are well known basins in Southern and Northern Vietnam since they