Optimal operation of the bac nam ha dainage system under climate change

ABSTRACT During the rainy season, frequent flooding by storm water is one of the most serious problems in lowland areas, causing heavy effect on transportation, agriculture, industries and many economic activities The required drainage water levels in this area are generally lower than the water levels of the virulent rivers Under such cases, pumping systems should be designed from a viewpoint of the integrated control floods Nam Ha lowland, in Vietnam, bounded by four surrounding rivers, is selected as a case study The operated plan in this area is the key factor for drainage and flood protection In this study, the mathematical model is used as a tool to evaluate the present drainage system as well as the scenario to improve its performance, considering the released water from agricultural areas Under climate change, there is change in rainfall of 14% in the region according to climate change scenario for Viet Nam updated 2016 of MONRE These changes were taken in to the simulation The results show both the flooding processes in the field as well as inundation areas and water levels along drainage channels It is found that the proposed model can be applied to evaluate integrated flood control systems for pumped field lowland Such a proper operating system provides an effective tool by means of which the drainage system can be operated appropriately taking account of rainfall intensity and effects of climate change i DECLARATION I hereby certify that the work presented in this thesis entitled, “Optimal operation of the Bac Nam Ha drainage system under climate change.” in partial fulfillment of the requirement for the award of the Master of Science in Integrated Water Resource Management, is my own work carried out under the supervision of Assoc Dr Nguyen Cao Don The matter embodied in this thesis has not been submitted by me for the award of any other degree or diploma Date: 15/04/2017 Signature: Nguyen Thi Huong ii ACKNOWLED GEMENT I would like to give many thanks to all people who has supported and assisted me during the Master Thesis Research Without their continuous support, encouragement and guidance, it would have been impossible for me to complete the study in time I would like to express my appreciation to Assoc Dr Nguyen Cao Don, my devoted mentor, for his unlimited encouragement, guidance, comments and technical supports on VRSAP modeling as well as thesis writing process from the beginning of thesis research He always keeps track on his students and brings them back to the right way I wish to thank Assoc Dr Nguyen Thu Hien for her feedbacks, comments and supports from the proposal process I would like to thank to the NICHE – VNM 106 Project for their financial support during the post graduate study at Thuyloi University I would like to thank to all teachers and professors of Thuyloi University Last but not least, I want to take this opportunity to show my appreciation to my parents, my siblings and all of my friends for their helps and encouragements iii TABLE CONTENTS ABSTRACT i DECLARATION .ii ACKNOWLED GEMENT iii INTRODUCTION 1.1 Introduction 1.2 Problem Statement .2 1.3 Objectives of the study .3 1.4 Research questions .3 1.5 Methodology 1.6 Structure of the thesis .4 CHAPTER 1: LITERATURE REVIEW 1.1 Climate change including floods .6 1.2 Overview of hydrodynamic models 1.3 Review on application of the hydrodynamic model 13 1.4 Review of climate change study in Viet Nam 15 1.5 Concluding remarks 17 CHAPTER STUDY AREA 19 2.1 Location of Bac Nam Ha 19 2.2 Topography 21 2.3 Zonation of the drainage system 22 2.4 Drainage channel systems 23 CHAPTER METHODOLOGY 26 3.1 Research framework 26 3.2 Data collection and data analysis .27 3.2.1 Pumping station system 27 3.2.2 Control sluices 29 3.2.3 Hydrological data 29 3.3 Introduction to a hydro dynamic model (VRSAP) Tools 31 3.3.1 VRSAP Model 31 3.3.2 Boundary condition 34 iv CHAPTER APPLICATION OF THE MODEL 35 4.1 Model settings 35 4.2 Boundary condition 36 4.2.1 Pumping station 36 4.2.2 Rainfall 37 4.3 Calibration 38 4.4 Model validation 40 4.5 Application of HD model for operational scenarios 40 4.5.1 Gate operating scenarios 40 4.5.2 Results and discussion .41 4.5.3 Total inundation 45 CONCLUSION AND RECOMMENDATION 47 Conclusion 47 REFERENCES 49 v LIST OF FIGURES Figure 1.1: Projected change in water cycle Source: (USGCRP (2009) Figure 2.1: Map showing the study area .20 Figure 3.1: Intergrated operational model .26 Figure 3.2: Modeling field plot .33 Figure 4.1: Schematic diagram of the drainage systems showing nodes, links and files plots .35 Figure 4.2: Rainfall pattern taking into account of climate change 38 Figure 4.3: The adjustment steps 38 Figure 4.4: Model calibration for water levels at NhuTrac and Cau Sat 40 Figure 4.5: Inundation area at NhuTrac drainage zone 41 Figure 4.6: Inundation area at Huu Bi drainage zone 42 Figure 4.7: Inundation area at CocThanh drainage zone .43 Figure 4.8: Inundation area at Vinh Tri drainage zone 44 Figure 4.9: Inundation area at Co Dam drainage zone 45 Figure 4.10: Graph of inundation area for drainage zones 45 Figure 4.11: Graph of situations giving the smallest inundation area 46 vi LIST OF TABLES Table 2.1 Field elevation distribution in the area of independent pumping stations 21 Table 2.2 Distribution of area by elevation for the area of pumping stations 22 Table 2.3 Main drainage canal system and works on the canal 24 Table 3.1 The source of required data for model 27 Table 3.2 Design parameters of independent pumping stations 27 Table 3.3 Monthly average precipitation of rainfall at gauging stations in the study area 31 Table 3.4 Maximum 1-day precipitation of rainfall at gauging stations in the study area 31 Table 4.1 Daily rainfall at Phu Ly station ……………………………………………36 Table 4.2 Daily rainfall at Phu Ly station under climate change…………………….36 vii ABBREVIATIONS DHI: Danish Hydraulic Institute DARD: Department of Agriculture and Rural Development GIS: Geographic Information System HD: Hydrodynamic Model NAM: Nedbor Afstromnings Model MRC: Mekong River Commission MONRE: Ministry of Natural Resources and Environment SWAT: Soil and Water Assessment Tool IPCC: Intergovernmental Panel on Climate Change RMSE: Root Mean Square Error UNDP: United Nations Development Program UNFCCC: United Nations Framework Convention on Climate Chang VRSAP: Vietnam River Systems and Plains WREA: Water Resources and Environment Administration WEAP: Water Evaluation and Planning viii INTRODUCTION 1.1 Introduction During the rainy season, frequent flooding by storm water is one of the most serious problems in lowland area, causing heavy effect on transportation, agriculture, industries and many economic activities The required drainage water levels in this area are generally lower than the water levels of the boundary rivers In the development of this area, conventional functional drainage systems have been built, including channels, sluiceways, gates, regulator, pumping stations, etc In operation, the drainage system should be operated appropriately taking account of tidal effect, rainfall intensity and reaching time of the rainwater Such a proper operating system has not been established yet in the region At present, the development of agriculture is extensive and intensive, based on the diversified crop patterns, two or three cropping seasons in a year, and high yielding crop varieties with high demands of irrigation and drainage and level of its management However, after many years, operation and having exploited for a long time, most of the drainage systems are heavily deteriorated, with uncompleted canals and control structures Generally, the drainage system in this area is no longer suitable for the present stage of the agricultural land use For these reasons, the improvement of drainage system’s operation is now very necessary and important Moreover, according to IPCC (Intergovernmental Panel on Climate Change) and MONRE (Department of Agriculture and Rural Development), Viet Nam is one of the countries being affected by climate change that sea level rise and saline water intrusion The average rise in the global sea level is expected to be 59cm by 2100, according to the highest greenhouse gas emission scenario used in the fourth assessment of the Intergovernmental Panel on Climate Change (IPCC) 2007 However, according to a medium global greenhouse gas emission scenario, the sea level rise along the Viet Nam coast would be on average of 75cm by 2100 The Viet Nam Government recognizes climate change as a major challenge In order to solve those existing problems, it is necessary to understand the characteristics of the complicated unsteady flow regime in the drainage canal system Simulation approach is the best way to estimate the unsteady flow and to give the best suitable measures for improving drainage systems Under such circumstances, pumping systems should be designed from a viewpoint of the integrated control floods Furthermore, Nam Ha is lowland, in Vietnam, bounded by four surrounding rivers, is selected as a case study The operation scheme in this area is the key factor for drainage and flood protection The mathematical model is applied as a tool to evaluate the present drainage system as well as the scenario to improve its performance, considering the released water from agricultural areas and climate change The results show both the flooding processes in the field as well as inundation areas and water levels along drainage channels It is found that the proposed model can be applied to evaluate integrated flood control systems for pumped field lowland Such a proper operating system provides an effective tool by means of which the drainage system can be operated appropriately taking account of tidal effect, rainfall intensity and reaching time of the rainwater This thesis aims to set up a model hydrodynamic flow to the river network with its pumping stations and other drainage facilities to find a suitable operation of gate regulators so as to minimize total flooded area under a rainfall event 1.2 Problem Statement Ha Nam and Nam Dinh provinces are located in the lowland regions The region is surrounded by large rivers like the Red river, Day river, the Dao river in infield in addition also Chau Giang river and some other smaller rivers The study area is frequently inundated during rainy season To resolve this situation, the system of large pumping stations was built in the year 1970 However, head works and canals and other drainage facilities were over 30 years of operation, and thus they have severely deteriorated The pumping equipment were not well performed The gate regulators that connect sub-drainage basin did not work properly and efficiently Therefore, in this study, aims at finding out a suitable operation of gate regulators so as to minimize total flooded area Annex A 3: Graph of inundation area for drainages: Case 26 to Case 39 Case 26 Case 27 case 28 60000 Inundation Area (ha) 50000 Case29 Case 30 Case 31 Case 32 Case33 40000 30000 20000 Case34 Case35 10000 0 100 200 300 400 500 600 700 800 Time (h) Case 36 Case 37 Case 38 Case 39 Annex A 4: Graph of inundation area for drainages: Case 40 to Case 52 Case40 Case41 60000 case 42 Inundation Area (ha) 50000 Case 43 Case 44 Case 45 Case 46 Case 47 Case48 40000 30000 20000 10000 0 100 200 300 400 Time (h) 56 500 600 700 800 Case 49 Case 50 Case 51 Case 52 Annex A 5: Graph of inundation area for drainages: Case 53 to Case 64 Case 51 Case 52 Case 53 Case 54 Case 55 case 56 Case 57 Case 58 Case59 Inundation Area (ha) 60000 50000 40000 30000 20000 10000 0 100 200 300 400 500 600 700 800 Time (h) Case 60 Case 61 Case 62 Annex A 6: Situations giving the smallest inundation area Case11 inundation Area (ha) 60000 50000 Case 18 40000 30000 case 39 20000 Case48 10000 0 100 200 300 400 Time (h) 57 500 600 700 800 Case 64 Annex A 7: Graph of inundation area at Nhu Trac drainage: Case to Case 12 Case0 6000 Case case inundation Area (ha) 5000 Case 4000 Case Case 3000 case 2000 Case Case 1000 Case 0 100 200 300 400 500 600 700 Case 10 Case 11 800 Time (h) Annex A 8: Graph of inundation area at Nhu Trac drainage: Case 13 to Case 25 Case 13 6000 Case 14 case 15 5000 Inundation Area (ha) Case 16 4000 Case 17 Case 18 3000 Case 19 Case 20 2000 Case 21 1000 Case 22 Case 23 0 100 200 300 400 Time (h) 58 500 600 700 800 Case 24 Case 25 Annex A 9: Graph of inundation area at Nhu Trac drainage: Case 26 toCase 39 6000 Inundation Area (ha) 5000 4000 3000 2000 1000 0 100 200 300 400 500 600 700 800 Time (h) Case 26 Case 27 case 28 Case 29 Case 30 Case 31 Case 32 Case3 Case3 Case3 Case 36 Case 37 Case 38 Case 39 Annex A 10: Graph of inundation area at Nhu Trac drainage: Case 40 to Case 52 6000 Inundation Area (ha) 5000 4000 3000 2000 1000 0 100 200 300 400 Time (h) 59 500 600 700 800 Case4 Case4 case 42 Case 43 Case 44 Case 45 Case 46 Case4 Case4 Case 49 Case 50 Case 51 Case 52 Annex A 11: Graph of inundation area at Nhu Trac drainage: Case 53 to Case 64 Case 53 6000 Case 54 Case 55 Inundation Area (ha) 5000 case56 4000 Case57 Case 58 3000 Case59 2000 Case 60 Case 61 1000 Case 62 0 100 200 300 400 500 600 700 Case 63 800 Time (h) Case 64 Annex A 12: Graph of inundation area at Co Dam drainage: Case to Case 12 Case Case1 12000 case Inundation Area (ha) 10000 Case Case 8000 Case5 6000 case Case 4000 Case 2000 Case Case 10 Case 11 Case12 100 200 300 400 Time (h) 60 500 600 700 800 Annex A 13: Graph of inundation area at Co Dam drainage: Case 13 to Case 25 12000 Inundation Area (ha) 10000 8000 6000 4000 2000 0 100 200 300 400 500 600 700 800 Time (h) Case 13 Case 14 case 15 Case 16 Case 17 Case 18 Case 19 Case 20 Case 21 Case 22 Case 23 Case 24 Case 25 Annex A 14: Graph of inundation area at Co Dam drainage: Case 26 to Case 39 Inundation Area (ha) 12000 10000 8000 6000 4000 2000 0 100 200 300 400 Time (h) 61 500 600 700 800 Case 26 Case 27 case 28 Case2 Case 30 Case 31 Case 32 Case3 Case3 Case3 Case 36 Case 37 Case 38 Case 39 Annex A 15: Graph of inundation area at Co Dam drainage: Case 40 to Case 52 Case40 60000 Case41 case 42 Inundation Area (ha) 50000 Case 43 Case 44 40000 Case 45 30000 Case 46 Case47 20000 Case48 10000 Case 49 Case 50 100 200 300 400 500 600 700 800 Time (h) Case 51 Case 52 Annex A 16: Graph of inundation area at Co Dam drainage: Case 53 to Case 64 Case 53 Inundation Area (ha) 12000 Case 54 Case 55 10000 case 56 8000 Case57 Case 58 6000 Case59 4000 Case 60 Case 61 2000 Case 62 0 100 200 300 400 Time (h) 62 500 600 700 800 Case 63 Case 64 Annex A 17: Graph of inundation are at Coc Thanh drainage: Case to Case 12 Inundation Area (ha) Case0 20000 Case1 18000 case2 16000 Case 14000 Case5 12000 case 10000 8000 Case 6000 Case 4000 Case 2000 0 100 200 300 400 500 600 700 800 Time (h) Case 10 Case 11 Case1 Annex A 18: Graph of inundation area at Coc Thanh drainage: Case 13 to Case 26 Case 13 Case 14 case 15 20000 Inundation Area (ha) 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 100 200 300 400 Time (h) 63 500 600 700 800 Case 16 Case 17 Case 18 Case 19 Case 20 Case 21 Case 22 Case 23 Case 24 Case 25 Annex A 19: Graph of inundation area at Coc Thanh drainage: Case 26 to Case 39 Case 26 Case 27 case 28 Case 29 Case 30 Case 31 Case 32 Case 33 Case 34 Case 35 Case 36 Case 37 20000 18000 Inundation Area (ha) 16000 14000 12000 10000 8000 6000 4000 2000 0 100 200 300 400 500 600 700 800 Time (h) Annex A 20: Graph of inundation area at Coc Thanh drainage: Case 40 to Case 52 Inundation Area (ha) Case 40 20000 Case 41 18000 case 42 16000 Case 43 14000 Case 44 12000 Case 45 10000 Case 46 8000 Case 47 6000 Case 48 4000 Case 49 2000 Case 50 100 200 300 400 Time (h) 64 500 600 700 800 Case 51 Case 52 Annex A 21: Graph of inundation area at Coc Thanh drainage: Case 53 to Case 64 Inundation Area (ha) Case 53 18000 Case 54 16000 Case 55 14000 case 56 12000 Case 57 10000 Case 58 8000 Case 59 6000 Case 60 4000 Case 61 2000 Case 62 0 100 200 300 400 500 600 700 800 Case 63 Case 64 Time (h) Annex A 22: Graph of inundation area at Huu Bi drainage: Case to Case 12 Inundation Area (ha) Case0 4000 Case1 3500 case2 3000 Case Case 2500 Case5 2000 case 1500 Case 1000 Case Case 500 Case 10 0 100 200 300 400 Time (h) 65 500 600 700 800 Case 11 Case12 Annex A 23: Graph of inundation area at Huu Bi drainage: Case 13 to Case 25 Inundation Area (ha) Case 13 4000 Case 14 3500 case 15 Case 16 3000 Case 17 2500 Case 18 2000 Case 19 1500 Case 20 1000 Case 21 Case 22 500 Case 23 0 100 200 300 400 500 600 700 800 Time (h) Case 24 Case 25 Annex A 24: Graph of inundation area at Huu Bi drainage: Case 26 to Case 39 Case 26 Case 27 case 28 4000 3500 Case29 Inundation Area (ha) 3000 Case 30 Case 31 Case 32 Case33 2500 2000 1500 Case34 1000 Case35 500 0 100 200 300 400 Time (h) 66 500 600 700 800 Case 36 Case 37 Case 38 Case 39 Annex A 25: Graph of inundation area at Huu Bi drainage: Case 40 to Case 52 Inundation Area (ha) Case 40 4000 Case 41 3500 Case 43 3000 Case 44 2500 Case 45 2000 Case 46 Case47 1500 Case48 1000 Case 49 500 Case 50 100 200 300 400 500 600 700 800 Time (h) Case 51 Case 52 Annex A 26: Graph of inundation area at Huu Bi drainage: Case 53 to Case 64 Inundation Area (ha) Case 53 4000 Case 54 3500 Case 55 3000 case 56 2500 Case 57 2000 Case 58 Case 59 1500 Case 60 1000 Case 61 500 Case 62 100 200 300 400 Time (h) 67 500 600 700 800 Case 63 Case 64 Annex A 27: Graph of inundation area at Vinh Tri drainage: Case to Case 12 Inundation Area (ha) Case0 18000 Case 16000 case 14000 Case 12000 Case 10000 Case 8000 6000 case 4000 Case 2000 Case Case 100 200 300 400 500 600 700 800 Time (h) Case 10 Annex A 28: Graph of inundation area at Vinh Tri drainage: Case 13 to Case 25 18000 Inundation Area (ha) 16000 14000 12000 10000 8000 6000 4000 2000 0 100 200 300 400 Time (h) 68 500 600 700 800 Case 13 Case 14 case 15 Case 16 Case 17 Case 18 Case 19 Case 20 Case 21 Case 22 Case 23 Case 24 Case 25 Annex A 29: Graph of inundation area at Vinh Tri drainage: Case 26 to Case 39 Inundation Area (ha) Case 26 18000 Case 27 16000 case 28 Case 29 14000 Case 30 12000 Case 31 10000 Case 32 8000 Case 33 6000 Case 34 4000 Case 35 Case 36 2000 Case 37 100 200 300 400 500 600 700 800 Case 38 Case 39 Time (h) Annex A 30: Graph of inundation area at Vinh Tri drainage: Case 40 to Case 52 Inundation Area (ha) Case 40 18000 Case 41 16000 case 42 14000 Case 43 12000 Case 44 10000 Case 45 Case 46 8000 Case 47 6000 Case 48 4000 Case 49 2000 Case 50 100 200 300 400 Time (h) 69 500 600 700 800 Case 51 Case 52 Annex A 31: Graph of inundation area at Vinh Tri drainage: Case 53 to Chase 64 Inundation Area (ha) Case 53 18000 Case 54 16000 Case 55 14000 case 56 12000 Case 57 10000 Case 58 8000 Case 59 6000 Case 60 4000 Case 61 2000 Case 62 0 100 200 300 400 Time (h) 70 500 600 700 800 Case 63 Case 64 ... certify that the work presented in this thesis entitled, ? ?Optimal operation of the Bac Nam Ha drainage system under climate change. ” in partial fulfillment of the requirement for the award of the. .. quantify the impact of climate change on global climate, water levels of the oceans of the world For each region, each country on the basis of global climate change scenarios will have the detailed... models and using them in solving the problem related to dam operation and climate change 1.4 Review of climate change study in Viet Nam Climate change is one of the most significant challenges facing