MINISTRY OF EDUCATION MINISTRY OF AGRICULTURE AND TRAINING AND RURAL DEVELOPMENT THUY LOI UNIVERSITY HOANG THI LINH GIANG MASTER THESIS HANOI, 2016 MINISTRY OF EDUCATION _ MINISTRY OF AGRICULTURE AND TRAINING AND RURAL DEVELOPMENT ‘THUY LOT UNIVERSITY HOANG THI LINH GIANG PREVENTIVE MEASURES FOR COASTAL EROSION IN CUA LO, TAM QUANG COMMUNE, NUI THANH DISTRICT, QUANG NAM PROVINCE Major: Coastal Engineering and Management Code : 62580203 MASTER THESIS SUPERVISOR: ASSOC. MAI VAN CONG HANOI, 2016 DECLARATION I hereby certify the work which is being presented in this thesis entitled, “Preventive measures for coastal erosion in Cua Lo, Tam Quang commune, Nui Thanh District, Quang Nam province.” in partial fulfillment of the requirement for the award of the Master of Coastal Engineering and Management, is an authentic record of my own work carried out under supervision of Assoc, Prof. Mai Van Cong. The matter embodied in this thesis has been submitted to UNDP in Vietnam and DMC under the framework of the project “Strengthening Institutional Capacity for Disaster Risk Management in Viet Nam Including Climate Change Related Risks (SCDM Phase II).
Ha Noi, December, 2016 Hoang Thi Linh Giang ACKNOWLEDGEMENTS First of all 1 would like to acknowledge the sponsors UNDP in Vietnam and DMC under the framework of project “Strengthening Institutional Capacity for Disaster Risk Management in Viet Nam Including Climate Change Related Risks (SCDM Phase 11) for the scholarship suppor. Towe special words of many thanks to Assoc, Prof, Dr. Mai Van Cong- my supervisor for his concer, guidance, enthusiasm, valuable advice and assistance with so much care. 1 would like to acknowledge Assoc.
Dr Tran Thanh Tung and Prof. Dr Thicu Quang Tuan who are main co-ordinator of this master program, making value contributions to success in Master course. I would like tos yy thanks to Professor Marcel Stive for his comment on proposed solutions. I also want to thank to M.
Nguyen Quang Duc Anh from VINWATER for his comments, supports in modeling work and sug lon, M. Le Duc Dung from VASI for his supports in data and ‘model validation. 1 would like to thanks faculty of Marine and Coastal Engineering of Thuy Loi University for providing support in numerous aspects amid the study. My high appreciation goes to all the lecturers who have taught and provided me with such valuable knowledge to my future career both in Vietnam and in the Netherland; my colleagues, friends and my classmates for their support and assistance.
Finally, I would like to keep the great thanks to my sweet family for their great support and always being source of encouragement, motivation and energy. TABLE OF CONTENTS DECLARATION. ‘TABLE OF CONTENT! LIST OF FIGURES. LIST OF TABLES.
Rationale of this research 2. 4, Research methodology and implementation. Structure of the thesis (CHAPTER I: LITERATURE REVIEW 3 1.1 Overview of erosion and sedimentation 3 1.1-§omme researches in foreign countries 3 1.Coastal erosion and shoreline changes researches in Vietnam.3 Recent coastal researches in Quang Nam province.Research method in erosion and sedimentation 12 1.Method of mapping- remote sensing 12 1.Field survey method.5 Statisical and synthetic analyzing method l3 CHAPTER II: OVERVIEW OF STUDY AREA.Study area description 4 2.Social-economic features 2B 24,Status of coastal erosion and existing coastal protection measures in study areas.Coastal development 28 CHAPTER Ill: ANALYSIS OF COASTAL EROSION PROCESS AND SHORELINE CHANGES IN THE STUDY AREA.Causes of coastal erosion in study area.1 Hypothesis I: Erosion caused by structural properties of the coast 37 3.Hypothesis 2: Erosion and shoreline changes caused by sea level rise and the extreme boundary conditions of hydrological factors 37 3.1-Erosion and shoreline changes caused by sea level rise 37 3.Bffect of typhoons and storm induced cross-shore erosion 38 3.Hypothesis 3: Erosion and shoreline changes caused by human actitities. Analysis of mechanisms for erosion and shoreline changes in the study area.
Model set up 48 3. Calibration and verification of simulation model, 5 3.3, Evaluation of the hydrodynamic regime in Cua Lo area 37 3. Hydrodynamic regime of Cua Lo area in winter 58 3. Hydrodynamic regime of Cua Lo area in summer 6l 3.
Hydrodynamic regime of Cua Lo area in flooding, 64 3. Conclusions 66 CHAPTER IV: POSSIBLE ALTERNATIVE COUNTERMEASURES 68 4.1, The common principles of planning countermeasures, 68 4. Proposed planning countermeasures for study area 68 43, Evaluating of planning countermeasures by modeling, 7 4. Extraction locations of the results from Mike 21/3 FM model 7 4.
Hydrodynamic regime and bed level change of Cua Loarea in summter.3, Hydrodynamic regime and bed level change of Cua Lo area in winter 82 43.4, Hydrodynamic regime and bed level change of Cua Lo area in ƒlooding. Evaluation of possible countermeasures. 90 CONCLUSIONS AND RECOMMENDATION 1. Appendix 1; Frequency table in Spring, Summer, Autumn, Winter at Ly Son station 100 Appendix 2: The result of calibration tidal model 104 Appendix 3: The result of verification tidal model 115 Appendix 4: Comparision of bed level change at 5 sections 122 LIST OF FIGURES Fig.2- 1: Study area Fig.2- 2: Wind rose at Ly Son (1985-2012) Fig.2- 3: Wave roses in March, April and May at Ly Son station Fig.2- 4: Wave roses in Jun, July and August at Ly Son station Fig.2- 5: Wave roses in September, October and November at Ly Son station Fig.2- 6: Wave roses in December, January and February at Ly Son station g.2- 7: River system Fig.2- 8; Discharge of Truong Giang river in flood season Fig.2- 9: Existing coastal protection measures in Cua Lo area (Nui Thanh) Fig.2- 10: Geo-textile (Intemet &Google Earth) Fig.2- 11: Geo-textile was destroyed in the southern of Cua Lo in 12/2013 Fig.2- 12: Approximately 30 m of existing revetments was seriously damage.2- 13: Large concrete blocks were capsized off the ground 26 Fig2- 14 Tam Hai revetment, Nui Thanh district, Quang Nam provinces.
were destroyed after only a short time in use (Internet &Google Earth), 26 Fig.2- 15: Waterway in Cua Lo river mouth(Internet &Google Earth) 27 Fig.2- 16: Eroded area in Ba Tinh, Nui Thanh, Quang Nam (Intemet &Google Earth) 27 Fig.2- 17: Coastal development (Google Earth) 29 Fig.2- 18: Average erosion rate in Cua Lo.2- 19: Average acct jon rate in Cua Lo.2- 20: Accretion-erosion in Cua Lo in the period from 1965 to 2014.3- 1: Main causes and factors causing coastal erosion and shoreline changes 36 Fig.3- 2: Historic tracks of storm events in the vicinity of the research site 39 Fig.3- 3: Historie relevant tracks of storm events in the vicinity ofthe research site 40 Fig.3- 4: Phu Ninh reservoir (Google Earth) 2 Fig.3- 5: Representative eross sections “4 Fig.3- 6: Extend oflarge domain model 49 Eig.3- 7: Nested detailed (small) model 50 Fig 3- 8: Bathymetry of large model sl Eig 3-9: Bathymetry ofsmall model sĩ Fig.3- 10: Boundary conditions of large model 32 FFig.3 1: The location of water level measuring stations 54 Fig.3- 12: The calibration result of water level at Son Tra station.3- 13: The calibration result of water level at Cua Dai station 5s Fig.3- 14: The verification result of water level at Cua Dai station 56 Fig.3- 15: The distribution of the characteristic waves of Cua Lo area in winter.S8 Fig3- 16: The distribution of total currents (speed and direction) when tide going up of Cua Lo area in winter so Eig3- 17: The distribution of total currents (speed and direction) when tide going down of Cua Lo area in winter 59 Fig.3- 18: Result extracted points from the model 60 Fig.3- 19: Current velocities at points in winter 60 Eig.3- 20: The distribution of the characteristic waves of Cua Lo area in summer.62 Fig3- 21: The distribution of total currents (speed and direction) when tide going up ‘of Cua Lo area in summer 62 Fig.3- 22: The distribution of total currents (speed and direction) when tide going down of Cua Lo area in summer 6 Tp 3- 23: Current velocities at points in summer “ Big 3: 24: Water level of Cua Lo area in flooding 6 Eig.3- 25: The distribution of total currents (speed and ditection) in flooding.3- 26: Current velocities at points in flooding 65 Fig: Master plan 1 n Fig.4- 3: Master plan 2 ” Big 4- 4: Extraction locations of the results from Mike 21/3 FM model n Fig. 5: The distribution of total currents (speed and direction) whea tide going up and down in summer of master plan | 78 Fig4- 6: The distribution of total currents (speed and direction) when tide going up and down in summer of master plan 2. 79 Fig4- 7: Bed level change in summer of master plan 1 80 Fig 4- 8: Bed level change in summer of master plan 2. 81 Fig4- 9: The distribution of total currents (speed and direction) when tide going up and down in winter of master plan 1 82 Fig.4- 10: The distribution of total currents (speed and direction) when tide going up and down in winter of master plan 2 83 Fig 4- 11: The distribution of the characteristic wave in winter of master plan 1.4- 12: The distribution of the characteristic wave in winter of master plan 2.4- 13: Bed level change in winter of master plan 1 85 Fig.4- 14: Bed level change in winter of master plan 2 86 Fig.4- 15: The distribution of total currents (speed and direction) in flooding of master plan 1 87 Fig.4- 16: The distribution of total currents (speed and direction in flooding of master plan 2 87 Fig 4- 17: Water level of master plan 1 88 Fig.4- 18: Water level of master plan 2.4- 19: Bed level change of master plan| 89 Fig.4- 20: Bed level change of master plan 2 90 LIST OF TABLES ‘Table 2- 1: Statistical wind speed (average and maximum) per month in Ly Son (1985- 2012) 16 ‘Table 2- 2: Wind speed statisti (average and maximum) in the direction of Ly Son (1985- 2012) 16 Table 2-3 Average erosion rate in Cua Lo 30 Table 2: 4: Average accretion rate in Cua Lo 31 Table 3-1 List ofthe typical storms in Quang Nam costal areas.
40 Table 3-2 ross section 1 44 Table 3-3 Cross section 2 Table 3-4 CERC calculation results 45 Table 3-5 Parameters of large model 5 Table 3-6 “The coordinates of measuring stations st Table 3-7: Wave height at Ly Son station in season (1985-2012) 58 Table 41 Ship size caleutates the navigation 69 Table 4-2: Preliminary planning of masterplan Ì Table 4-3 Preliminary planning of master plan 2 15 Table 4 4 Extraction coordinates of the results from Mike 21/3 FM model 1 Table 4- 5 Evaluation possible countermeasures 93 INTRODUCTION 1. Rationale of this research Coastal erosion and sedimentation become serious at many coastal sections in the Central Vietnam in general and Cua Lo, Tam Quang commune, Nui Thanh district, ‘Quang Nam province in particular, ‘This causes many adverse consequences on daily life as well as social economic development, such as house collapsed, public works destroyed, shoreline retreated and crop yields reduced. This situation triggers local and central government to urgently seek for a solution to minimize the erosion and sedimentation problems. Proposing possible solution for Cua Lo location, Tam Quang ‘commune, Nui Thanh district, Quang Nam province is therefore very important 2.
Research objectives This study comes up with the following objectives: ~ Analysis of erosion causes and determination of driving forces that lead to the accretion, erosion of the study area ~ Proposing possible solutions for coastal erosion prevention in Cua Lo, Tam Quang ‘commune, Nui Thanh District, Quang Nam province. Focus area ~ Focus area of thi study is a coastal section around the Cua Lo river mouth, belonging toTam Quang commune, Nui Thanh district within the geographical limit of 15°3025. Research methodology and implementation Research methodology and implementation as following. faa) fae a F=lr===! I com I 1 ot 1 = ¬ =!) 7 Research methodology and implementation 5.