Université de Liège NICHE-CEM &TLU-ULG MASTER PROGRAM MASTER THESIS CONSTRUCTING THE FLOOD HAZARD MAP FOR DOWNSTREAM OF DA BAN RESERVOIR, KHANH HOA PROVINCE, VIET NAM Submitted by NGUYEN MANH KIEN Ha Noi, August 2016 THUY LOI UNIVERSITY & UNIVERSITY OF LIEGE oe (st ow ee Université de Liềge NICHE-CEM &TLU-ULG MASTER PROGRAM MASTER THESIS CONSTRUCTING THE FLOOD HAZARD MAP FOR DOWNSTREAM OF DA BAN RESERVOIR, KHANH HOA. PROVINCE, VIET NAM ‘Student's Name + Nguyen Manh Kien Birthday January 05, 1980. Student Code 1481580203008 Email address Kiennm4125/2wruvn Mobile Phone Number 384919209088. Supervisor + Assoc, Prof.
NghiemTien Lam, Email lam wruxn Co-supervisor : Prof. HIVER Jean-Michel Email 2Jean-MiehelHiver/2ulbaae.be Ha Noi, August 2016 Niche- EMS&-TLU-ULG master program Master thesis DECLARATION declare that this submission is my own original work, and I have not used any source ‘or mean without proper citation inthe text. Any idea from others is clearly marked. This thesis contains no material published elsewhere or extracted in whole or in pat from a thesis or any other degree or diploma.
Ha Noi, August 2016 ‘Nguyen Manh Kien Niche-CEM&TLU-ULG master program Master thesis ACKNOWLEDGEMENT During last six months of research and prepare of this master thesis, I have been ‘accompanied and supported by many people. I would like to thank them all for their support, guidance and encouragement throughout this work. Firstly, I would like to express my sincere gratitude to my supervisor, Assoc. Dr NghiemTien Lam, for his guidance, support, and provision of critical information sources for me to complete my research, [also really appreciate all the support that I have received from my co-supervisor, Profit.
HIVER Jean-Michel, who provided great recommendations and lots of references for my thesis writing Secondly, I would like to warmly thank all the lecturers in NICHE-CEM & TLU-ULG. Masters` program for providing me so much knowledge during this course. ‘Thirdly, I would like to thank Song Da Joint Stock Company for giving me access to a Jot of important data and information on my selected atea for this thesis ‘And last but not least, I would like to thank my family and friends, who always stay by my side and have helped me a lot to finish this program, Niche-CEM&TLU-ULG master program Master thesis CONTENTS CHAPTER I: INTRODUCTION LL Problem statement. The meaning of flood map.
3 14 Objectives and methods: 4 LS Structure of thesis 5 CHAPTER 2: SOCIAL AND NATURAL CONDITIONS OF THE STUDY AREA 6 2.1 Natural condition of study area.1 Geographical location of study area 6 2.3 Climatic and hydrographical conditions 7 2.2 Socio-economic conditions. 0 Flood risk in downstream of Da Ban reserVoif. CHAPTER 3: THEORETICAL BASIC FOR FLOOD MAPPING.1 Background of flood mapping, 2 3.2 Objectives of this tool 2 3.13 Flood mapping process 12 3.14 Products of flood hazard map “ 3.2 General about the hydraulie problems in river network.1 ID steady Flow Is 3.22 ID unsteady Flow 16 3.3 2D unsteady flow hydrodynamics " 3. General about the hydraulic model 18 34 18 3.2 HEC-RAS two-dimensional flow modeling capabilities for calculation case of this study 20 3.43 Basic steps to modeling.
21 CHAPTER 4: CONSTRUCTING THE FLOOD MAP OF STUDY AREA.23 Niche-CEM&TLU-ULG master program Master thesis 4.2 Topography data 27 42⁄3 - Landuse data 28 424 Hydrologic data 29 software application to construct DEM data, cross-section data, 30 43.1 DEM data 30 432 Cross-seetional data of Da Ban river 30 433° Land cover data 31 44 HEC-RAS modeling application for flood simulation and caleuladion.1 Selection and construction of model domain 32 44.2 Developing a terrain model for use in 2D modeling and results in mapping 32 443 Development of a 2D model 36 444 Creating a spatially varied Manning's roughness layer 39 448 Boundary conditions 4B 44.6 Initial conditions 4 447 Dambreak analysis. 4 44⁄8 Running the unsteady flow model sĩ 449° Viewing2D output using RAS Mapper. Validation numerical model with analytical solution.1 Analytical Solution by Ritter 6s 452. Modeling the 2D Dam-Break wave ø 4.53 Comparing the model results and the analytical solution by Ritter (1892).62 Considering the factors affect the model results B 4.63 Choosing position on model for analyzing results 4 464 Sensitivity testing results 75 465 Conclusion 80 47.
Constructing flood hazard map by ArcGIS Niehe-CEM&TLU-ULG master program Master thesis CONCLUSIONS AND RECOMMENDATIONS. LIST OF FIGURES Figure 1: Geographical location of study area (souree: Google Map), 6 Figure 2: Representation of terms inthe energy equation 16 Figure3: Implementation diagram, 23 Figure 4: Da Ban reservoir, 24 Figure 5: Headworks before upgrading. 2 Figure 6: Headworks attr upgrading. 25 Figure 7: Inner stope of earth dam, 25 Figure8: Outer slope of dam, 25 Figure 9: Existing spillway 26 Figure 10: Intake 26 Figure 11: New spillway.
2 Figure 12: Da Bạn tiệt, 2 Figure 13: (DEM) 30mx30m of study area. 28 Figure 14: LandsatGLS\TM_Muhispectal_2000, 28 Figure 15: Chart ofhydrograph with iequcney 0. 29 Figure 16: Chart ofhydrograph with frequency 0,1%. 29 Figure 17: DEM study area, 30 Figure 18: Create cross sectional data for Da Ban river 31 Figure 19: Land cover of study area from Landsat sources.
31 Figure 20: Downstream of Da Ban reservoir. 32 Figure 21: RAS Mapper with a Terrain Data Layer added 33 Figure 22: RAS mapper with a channel (iver) terrain daa layer created 34 Figure 23: Original terrain model (top) and new terrain model with channel data (bottom).35 Figure 24: HEC-RAS 2D modeling computational mesh terminology 36 Figure 25: 2D computational mesh 37 Figure 26; 2D flow area mesh generation editor, 37 Figure 27: The storage area connected to the 2D Tlow are, 38 Figure 28: Adding the parameter ofthe reservoir. 38 Figure 29: SA/2D Area Hydraulic Connection editor. 39 Figure 30:Parameters ofa,new spillway and b, gates.
39 Figure 31: RAS Mapper’s new land classification ái Figure 32: Set Manning’sn override land cover values at some regions 2 Figure 35: Spatially varied Manning's roughness layer dã Figure 34: Boundary condition 44 Figure 35: Hydrograph with frequeney 0.5% 44 ydrograph with frequency 0 45 Figure 37: Normal depth in downstream 45 Figure 38: Initial condition of Reservoir 46 Figure 39: 2D flow area computational options 4 Niehe-CEM&TLU-ULG master program Master thesis Figure 4: Breach parameter caleulatr from regression equations 49 Figure 41 Shape and dimensions of calculated breach 40 Figure 42 Flow hydrographs ffom dam to downstream without dam break (Mood frequency 019) 50 Figure 43 Flow hydrographs from dam to downstream effect by dam break (lood frequeney 019) SI Figure 44 ‘Unsteady flow analysis window for a plan (plan 3). 56 Figure 45 Display results map parameters 37 Figure 46 RAS Mapper with depth results layers, 37 Figure 47: RAS Mapper with velocity results layers. ` Figure 4 RAS Mapper with WSE Results Layers. 59 Figure 40 Example Time Series Plot of Depth from three different Plan, 0 Figure 50: [Example Time Series Pot ofVelocity from thee different Plan.
61 Figure 51 ‘Example Time Series Pot of WSE from three different Plans. 62 Figure 82: Example velocity plot with color and diection/magnitude arrows. 6 Figure 83: Example ofthe particle tracing visualization option on top oFa depth layer.63 Figure 54: Profile Line tumed on and selected for plotting options 4 Figure 5S Example profile line plot of Water Surface Elevation (WSE) 64 Figure 56 Results Mapping Window: 65 Figure 57 Analytical solution by Ritter (water height) 6 Figure 58: Geometry model 61 Figure 59 Hydraulic structure with a dam break, 6 Figure 60 ‘Water hight follow model a 0s. 6 Figure 61 ‘Water depth profile along the river at 20s.
6 Figure 62 Water depth profile along the river at 40s. 0 Figure 63: ‘Water depth profile along the river at 608. 0 Figure 64: Analytical solution by Ritter (blue) and simulated results (orange): water depth at on n Figure 65 Analytical solution by Ritter (blue) and simulated results (orange): water depth at rs Figure 66: soloion by Ritter (blue) and simulated results (orange): water depth at 60s n Figure 67 ‘The position on model for analyzing results T5 Figure 68: “The water depth at point 3 in Sensitivity test cases of values T6 Figure 69 The velocity at point 3 n Sensitivity test cases n Figure 70: ‘The water dept at point 3 in Sensitivity test eases of mesh size T8 Figure 71 ‘The velocity at point 3 in Sensitivity test cases of mesh size. 78 Figure 72: ‘Computed tim step ìsŠ seconds and 2 minutes at point 3.
19 Figur 73 Breach bottom elevation is S6m and 46m (Sensitivity testing) at point 1 80 Figure 74 Flood hazard map in case of flood frequency 0. 83 Figure 75: Flood hazard map in ease of flood frequency 0.1% ¬ Figure 76 Flood hazard map in dam break case with flood frequency 0.1% 85 Figure 77 A resident area before and after covered by flood water, 87 Figure 78: Velocity changes from river to floodplain, 87 Figure 19 The flow through a resident are with the discharge of S00 (mis) ` Niehe-CEM&TLU-ULG master program Master thesis LIST OF TABLES “TableI: Climate specification 8 ‘Table2: Climate factors ofthe itrigated area, 1 Table 3: Meximum wind speed. # Table4: Evaporation 9 Table5: Evaporation loss. ° ‘Table 6: Rainfall 9 Table 7: Network and available surveyed factors, 9 ‘Table&: Flow statistics at Da Bạn, ° ‘Table 9: Flow distribution at Da Bạn, ° Table 10; Flow and total flood.
10 ‘Table 11: Situation of sol and forest sources 10 ‘Table 12; Elevation volume eure. 24 Table 13: Max flow and total flow in Da Ban in accordance with frequencies, » Table 14; Manning's n values are used for the model 40 ‘Table 15: Eddie viscosity transverse mixing coefficients 33 Table 16; Calculation cases. 5s Table 17; Caleulation eases of Sensitivity test. T3 Niche-CEM&TLU-ULG master program Master thesis CHAPTER 1: INTRODUCTION LA Problem statement Viet Nam has abundant and diverse water resources with dense river network, However, water discharge is not distributed evenly over different seasons in a year.
Discharge in the rainy season is much greater than that in the dry season, ‘As an agricultural country in its process of indus alization, Vietnam has built thousands of big and small reservoits on river basins in order to regulate water flow and reduce flood's impact, to supply water for irrigation in agriculture and aquaculture, and to generate hydropower, ete. Construction ofreservoirs offered tremendous efficieney to economic sectors Construction of reservoirs raised a major concern for safety due to potential risks lo ‘downstream areas, for example whenever a major flood appears. A large flood flow or break of dam flow leads to a sudden rise of water level, and higher velocity in ‘downstream, This situation represents a serious threat to the lives and properties of people living atthe project's downstream areas, Most ofthe reservoirs were designed following outdated standards and are not matching for current national and international standards. serious ‘degradation of upstream forest areas leads to more unpredictable and complicated flood patterns.
Being aware of the situation, the project VWRAP has provided Vietnam Government financial ass tance in strategic change with the capital loan. This loan was to upgrade ‘and modernize the irrigation system, improving irigation services through management improvement, operation, maintenance, and financial management, Notably, the effort also encouraged active participation of water users, especially farmers, In 2000, Ministry of Agriculture and Rural Development, together with World Bank s ‘consultants, investigated and determined 6 priority subprojects as part ofthe mentioned Toan, as follows: ~ Dau Tieng water resources subproject. Niche-CEM&TLU-ULG master program Master thesis = Yen Lap water resources subprojeet. = Ke Go water resources subproject.
= Cam Son - Cau Son water resources subproject. = Da Ban water resources subproject.