DECLARATION I hereby declare that is the research work by myself under the supervisions of Dr Nguyen Quang Chien and Assoc Prof Dr Tran Thanh Tung The results and conclusions of the thesis are fidelity, which are not copied from any sources and any forms The reference documents relevant sources, the thesis has cited and recorded as prescribed The matter embodied in this thesis has not been submitted by me for the award of any other degree or diploma Hanoi, 15 May 2018 Author Pham Hoai Thuong i ACKNOWLEDGEMENTS First of all, I would like to express my special thanks to my supervisors Dr Nguyen Quang Chien and Assoc Prof Dr Tran Thanh Tung for their patience, enthusiasm and immense knowledge, without them my research study would not have been succeeded I sincerely thank all the lecturers who taught me in the program especially the lecturers from the Faculty of Marine and Coastal Engineering of Thuyloi University for their useful and interesting lectures I also would like to acknowledge Prof Dr Marcel Stive and Assoc Prof Henk Jan Verhagen for their support and inspiration when I was studying in the Netherlands Finally, I am deeply grateful to my family for their great care and encouragement ii CONTENTS LIST OF TABLES vii LIST OF FIGURES ix INTRODUCTION Problem definition .1 Research Objectives and Research Questions Approach and Methodology CHAPER1: LITERATURE REVIEW 1.1 The characteristics of mangrove species 1.1.1 Sonneratia caseolaris (Vietnamese name: Cây Bần chua) 1.1.2 Kandelia obovata (Vietnamese name: Trang) 1.2 The mechanism of wave attenuation through mangroves forest .10 1.3 SWAN-VEG Model 11 1.4 Some studies about wave attenuation by mangrove forest in Vietnam 13 CHAPTER 2: STUDY AREA 16 2.1 Location 16 2.2 The reality of mangroves forest .17 2.3 State of the dyke system 19 2.4 Other Conditions 21 2.4.1 Topography .21 2.4.2 Wind 22 2.4.3 Wave 22 iii 2.4.4 Tide 22 2.4.5 Storm 24 2.4.6 Temperature 25 2.4.7 Rain fall .25 2.4.8 Sunny hour 25 2.4.9 Humidity 26 2.4.10 Salinity 26 2.4.11 Bed characteristic 26 CHAPTER 3: WAVE ATTENUATION THROUGH MANGROVES FOREST 27 3.1 Selection of appropriate types of mangroves and vegetation parameters 27 3.2 Determine bed elevation to plant mangroves 29 3.3 Scenario selection 31 3.4 Computational domain and bathymetry 32 3.5 Hydro-meteorologic condition for normal case .33 3.5.1 Wave parameters .33 3.5.2 Wind parameters .35 3.5.3 Water level 36 3.6 Hydro-meteorologic condition for storm case 36 3.6.1 Design return period 36 3.6.2 Design water level .36 3.6.3 Offshore wave parameters .37 3.7 Simulation results .38 iv 3.7.1 Wave propagation using Swan 2D model 38 3.7.2 Results of wave attenuation by mangrove forest 40 3.8 Comparison with an empirical formula 50 CHAPTER 4: IMPACT OF CLIMATE CHANGE TO MANGROVE FOREST AND WAVE ATTENUATION IN CLIMATE CHANGE SCENARIOS 53 4.1 Impact of climate change and other factors to the development of mangrove forest 53 4.1.1 Sea level rise .53 4.1.2 Rise in surface temperature .54 4.1.3 Storm and extreme weather events 55 4.1.4 Other factors 55 4.2 Wave attenuation through mangrove forest in Climate change scenarios .56 4.2.1 Input data 56 4.2.2 Results .58 CONCLUSIONS AND RECOMMENDATIONS 60 Conclusions 60 Recommendations 61 ANNEX 65 Annex 1: SWAN 2D input file 65 Annex 1.1: SWAN 2D input file in Scenario .65 Annex 1.2: SWAN 2D input file in Scenario .66 Annex 1.3: SWAN 2D input in Scenario 67 v Annex 2: SWAN-VEG input file 68 Annex 2.1: Example of SWAN-VEG input file in normal condition, SE monsoon .68 Annex 2.2: Example of SWAN-VEG input file in normal condition, NE monsoon .69 Annex 2.3: Example of SWAN-VEG input file in Storm condition .70 Annex : Hs, Kt, R in Scenario1,2,3 with 5-year-old tree and 9-year-old tree 71 Annex 3.1: Hs in scenario 1,2,3 with 5-year-old tree and 9-year-old tree 71 Annex 3.2: Kt in scenario 1,2,3 with 5-year-old tree and 9-year-old tree 73 Annex 3.3: R in scenario 1,2,3 with 5-year-old tree and 9-year-old tree 76 Annex 4: Hs in scenarios in which density of mangrove forest varies .79 Annex 5: Hs in Scenarios with and without climate change .83 Annex 6: Some photos from the field trip 85 vi LIST OF TABLES Table 0.1 Distribution and area of mangroves forests in Vietnam Table 0.2 Mangroves forest in front of the dyke .4 Table 1.1 Some studies about wave attenuation by mangrove forest in Vietnam 14 Table 2.1 Characteristic of the sea dykes and revetments .20 Table 2.2 Characteristics of tide along Vietnamese coast .23 Table 3.1 Parameters of K obovata .28 Table 3.2 Parameters of S.caseolaris 28 Table 3.3 Exposed time in a day in some assumed bed elevation .30 Table 3.4 Input data in SWAN Simulation 32 Table 3.5 Statistical offshore wave data 34 Table 3.6 Wind and wave parameters in Van Ly Station 38 Table 3.7 Wave properties at nearshore locations (A and B) 40 Table 3.8 Representative diameters of wave attenuation corresponding with SCN1,2,3 .45 Table 3.9 Representative diameters of wave attenuation corresponding with survival rate 46 Table 3.10 Representive diameters of wave attenuation corresponding with width of mangrove forest .47 Table 3.11 Representative diameters of wave attenuation corresponding with width of mangrove forest .49 Table 3.12 Comparison results of wave height behind mangrove to Bao‟study 51 vii Table 4.1 Sea level rise in location from Hon Dau to Deo Ngang according to the scenarios of climate change and sea level rise 57 Table 4.2 Water level in Scenarios 58 Table 4.3 Wave height behind mangrove forest and wave attenuation coefficient 59 viii LIST OF FIGURES Figure 0.1 Tracks of Global Tropical Cyclones since records began 1958-2015 (Source: seawapa.org) .1 Figure 0.2 Map of Vietnamese Provinces (Source: Wikipedia) Figure 0.3 Approach of the research .7 Figure 1.1 Sonneratia caseolaris .9 Figure 1.2 Kandelia obovata Figure 1.3 Schematic diagram of the mechanism by which mangrove forests reduce wave energy[2] 10 Figure 1.4 Schematization of SWAN-VEG model [10] 12 Figure 1.5 Schematization of mangroves is SWAN-VEG 13 Figure 2.1 Map of Hau Loc (source Google Map) 16 Figure 2.2 Study area (source: Google Earth) .17 Figure 2.3 Mangroves area in Hau Loc District from 1990 to 2015 .18 Figure 2.4 Topography of study area 21 Figure 2.5 Water level in study area 24 Figure 2.6 Tracks of storms in East Sea 24 Figure 2.7 Monthly average temperature 25 Figure 3.1 Illustration for calculation exposed time corresponding to the bed elevation .29 Figure 3.2 Relationship between bed elevation and exposed time in Hau Loc beach 30 Figure 3.3 Cross section in 1D model 33 ix Figure 3.4 Wave rose from offshore in Thanh Hoa from 2006 to 2017 .33 Figure 3.5 Relationship between wave height and wave period 35 Figure 3.6 Design water level in Hau Loc –Thanh Hoa 37 Figure 3.7 Distribution of wave height in scenario SCN1 38 Figure 3.8 Distribution of wave height in scenario SCN2 39 Figure 3.9 Distribution of wave height in scenario SCN3 39 Figure 3.10 Wave height in mangrove forest in scenarios 41 Figure 3.11 Wave height in mangrove forest in scenario 41 Figure 3.12 Wave height in mangrove forest in scenario 42 Figure 3.13 Wave height in mangrove forest in scenario 42 Figure 3.14 Kt in normal condition .44 Figure 3.15 Kt in storm condition 44 Figure 3.16 R in normal condition 44 Figure 3.17 R in storm condition 44 Figure 3.18 Wave attenuation by mangrove forest corresponding to some survival rates .46 Figure 3.19 Relationship between survival rate and wave attenuation 46 Figure 3.20 Wave attenuation by mangrove forest corresponding to several width of the forest 47 Figure 3.21Relationship between width of mangrove forest and wave attenuation ecofficient 48 Figure 3.22 Wave attenuation by mangrove forest corresponding to some density of mangrove forest 49 x Botlev (m) Distance from the dyke (m) 0.5278 112 0.5236 Kt Ban9_ SCN1 K obovata5_ SCN1 Trang9_ SCN1 Ban 5_ SCN2 Ban9_ SCN2 Trang 5_ SCN2 Trang9_ SCN2 0.348 0.249 0.441 0.313 0.364 0.250 0.549 0.288 0.449 105 0.341 0.244 0.433 0.306 0.356 0.244 0.540 0.282 0.5175 98 0.334 0.238 0.425 0.300 0.349 0.239 0.532 0.5084 91 0.327 0.233 0.417 0.294 0.343 0.233 0.4993 84 0.321 0.228 0.409 0.289 0.336 0.4902 77 0.315 0.223 0.402 0.283 0.4811 70 0.309 0.218 0.395 0.464 63 0.303 0.214 0.4347 56 0.298 0.4055 49 0.3762 Ban5_ SCN1 Trang5_ SCN3 Trang9_ SCN3 0.366 0.803 0.629 0.446 0.365 0.801 0.626 0.276 0.444 0.364 0.799 0.623 0.524 0.271 0.441 0.362 0.797 0.621 0.228 0.515 0.265 0.439 0.361 0.795 0.618 0.330 0.224 0.507 0.260 0.437 0.359 0.793 0.616 0.278 0.323 0.219 0.499 0.255 0.435 0.358 0.791 0.614 0.388 0.273 0.318 0.215 0.492 0.251 0.433 0.357 0.788 0.611 0.210 0.381 0.269 0.312 0.210 0.484 0.246 0.432 0.355 0.786 0.609 0.292 0.206 0.374 0.264 0.306 0.206 0.477 0.242 0.430 0.354 0.784 0.606 42 0.287 0.202 0.367 0.260 0.301 0.202 0.469 0.238 0.428 0.352 0.781 0.603 0.3469 35 0.282 0.198 0.361 0.256 0.296 0.198 0.462 0.234 0.426 0.351 0.778 0.601 0.3146 28 0.277 0.194 0.354 0.252 0.290 0.195 0.454 0.230 0.425 0.349 0.775 0.597 0.2779 21 0.272 0.190 0.348 0.248 0.285 0.191 0.447 0.226 0.423 0.348 0.772 0.594 0.2413 14 0.267 0.187 0.342 0.244 0.280 0.188 0.439 0.222 0.421 0.346 0.769 0.591 0.2046 0.262 0.183 0.336 0.241 0.276 0.184 0.432 0.219 0.419 0.345 0.765 0.587 0.1679 0.257 0.180 0.330 0.238 0.271 0.181 0.424 0.215 0.417 0.343 0.761 0.583 75 Ban5_ SCN3 Ban9_ SCN3 Annex 3.3: R in scenario 1,2,3 with 5-year-old tree and 9-year-old tree Botlev (m) Distance from the dyke Ban9_ SCN1 Trang5_ SCN1 Trang9_ SCN1 Ban 5_ SCN2 Ban9_ SCN2 Trang 5_ SCN2 Trang9_ SCN2 0.6342 357 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 0.6372 350 0.970 0.953 0.978 0.963 0.973 0.954 0.987 0.960 0.964 0.938 0.990 0.976 0.6403 343 0.932 0.895 0.951 0.916 0.938 0.897 0.970 0.909 0.916 0.859 0.979 0.946 0.6433 336 0.893 0.838 0.923 0.870 0.902 0.841 0.951 0.859 0.870 0.786 0.967 0.917 0.6463 329 0.856 0.786 0.896 0.827 0.868 0.788 0.934 0.811 0.828 0.722 0.956 0.890 0.6493 322 0.821 0.738 0.870 0.787 0.835 0.741 0.916 0.768 0.790 0.668 0.946 0.865 0.6523 315 0.789 0.696 0.846 0.750 0.804 0.698 0.899 0.729 0.756 0.624 0.936 0.842 0.6552 308 0.759 0.657 0.822 0.716 0.775 0.659 0.882 0.693 0.726 0.586 0.928 0.823 0.6579 301 0.730 0.622 0.800 0.685 0.747 0.624 0.866 0.661 0.698 0.555 0.919 0.807 0.6605 294 0.704 0.591 0.779 0.657 0.722 0.593 0.850 0.631 0.674 0.528 0.911 0.792 0.6632 287 0.679 0.563 0.759 0.630 0.697 0.564 0.835 0.604 0.652 0.506 0.904 0.779 0.6659 280 0.656 0.537 0.740 0.606 0.674 0.538 0.821 0.579 0.632 0.487 0.896 0.767 0.666 273 0.634 0.513 0.722 0.584 0.653 0.514 0.806 0.555 0.614 0.470 0.890 0.757 0.662 266 0.614 0.492 0.705 0.563 0.633 0.492 0.793 0.534 0.598 0.456 0.883 0.746 0.658 259 0.595 0.472 0.689 0.543 0.614 0.472 0.779 0.514 0.584 0.443 0.877 0.737 0.6541 252 0.577 0.453 0.673 0.525 0.595 0.453 0.766 0.496 0.571 0.433 0.871 0.728 0.6501 245 0.559 0.436 0.657 0.508 0.578 0.436 0.753 0.479 0.559 0.424 0.866 0.720 0.645 238 0.543 0.420 0.642 0.492 0.562 0.420 0.740 0.463 0.549 0.416 0.860 0.712 Ban5_ SCN1 76 Ban5_ SCN3 Ban9_ SCN3 Trang5_ SCN3 Trang9_ SCN3 Botlev (m) Distance from the dyke Ban9_ SCN1 Trang5_ SCN1 Trang9_ SCN1 Ban 5_ SCN2 Ban9_ SCN2 Trang 5_ SCN2 Trang9_ SCN2 0.6382 231 0.528 0.405 0.628 0.477 0.546 0.405 0.728 0.448 0.539 0.409 0.855 0.705 0.6314 224 0.513 0.391 0.614 0.463 0.531 0.391 0.716 0.434 0.530 0.403 0.851 0.698 0.6246 217 0.499 0.378 0.601 0.449 0.517 0.378 0.704 0.421 0.522 0.399 0.847 0.692 0.6178 210 0.486 0.366 0.588 0.437 0.503 0.366 0.692 0.408 0.514 0.395 0.843 0.686 0.6109 203 0.473 0.355 0.575 0.425 0.490 0.355 0.680 0.397 0.507 0.391 0.839 0.680 0.6038 196 0.461 0.344 0.563 0.414 0.478 0.344 0.669 0.386 0.500 0.388 0.836 0.675 0.5966 189 0.449 0.334 0.551 0.403 0.466 0.333 0.658 0.375 0.494 0.386 0.833 0.670 0.5895 182 0.438 0.324 0.540 0.393 0.455 0.324 0.647 0.365 0.488 0.383 0.830 0.665 0.5824 175 0.427 0.315 0.528 0.383 0.444 0.315 0.637 0.356 0.483 0.381 0.827 0.661 0.5752 168 0.417 0.306 0.518 0.374 0.434 0.306 0.626 0.347 0.478 0.379 0.824 0.656 0.5679 161 0.407 0.298 0.507 0.365 0.424 0.298 0.616 0.338 0.474 0.377 0.821 0.652 0.5607 154 0.398 0.290 0.497 0.356 0.414 0.290 0.606 0.330 0.469 0.375 0.818 0.648 0.5534 147 0.389 0.282 0.487 0.348 0.405 0.282 0.596 0.322 0.465 0.374 0.816 0.645 0.5461 140 0.380 0.275 0.477 0.341 0.396 0.275 0.586 0.315 0.462 0.372 0.813 0.641 0.5401 133 0.372 0.268 0.468 0.333 0.387 0.268 0.577 0.308 0.458 0.371 0.810 0.638 0.536 126 0.364 0.262 0.459 0.326 0.379 0.262 0.567 0.301 0.455 0.369 0.808 0.635 0.5319 119 0.356 0.255 0.450 0.319 0.371 0.256 0.558 0.294 0.452 0.368 0.806 0.631 0.5278 112 0.348 0.249 0.441 0.313 0.364 0.250 0.549 0.288 0.449 0.366 0.803 0.629 0.5236 105 0.341 0.244 0.433 0.306 0.356 0.244 0.540 0.282 0.446 0.365 0.801 0.626 Ban5_ SCN1 77 Ban5_ SCN3 Ban9_ SCN3 Trang5_ SCN3 Trang9_ SCN3 Botlev (m) Distance from the dyke Ban9_ SCN1 Trang5_ SCN1 Trang9_ SCN1 Ban 5_ SCN2 Ban9_ SCN2 Trang 5_ SCN2 Trang9_ SCN2 0.5175 98 0.334 0.238 0.425 0.300 0.349 0.239 0.532 0.276 0.444 0.364 0.799 0.623 0.5084 91 0.327 0.233 0.417 0.294 0.343 0.233 0.524 0.271 0.441 0.362 0.797 0.621 0.4993 84 0.321 0.228 0.409 0.289 0.336 0.228 0.515 0.265 0.439 0.361 0.795 0.618 0.4902 77 0.315 0.223 0.402 0.283 0.330 0.224 0.507 0.260 0.437 0.359 0.793 0.616 0.4811 70 0.309 0.218 0.395 0.278 0.323 0.219 0.499 0.255 0.435 0.358 0.791 0.614 0.464 63 0.303 0.214 0.388 0.273 0.318 0.215 0.492 0.251 0.433 0.357 0.788 0.611 0.4347 56 0.298 0.210 0.381 0.269 0.312 0.210 0.484 0.246 0.432 0.355 0.786 0.609 0.4055 49 0.292 0.206 0.374 0.264 0.306 0.206 0.477 0.242 0.430 0.354 0.784 0.606 0.3762 42 0.287 0.202 0.367 0.260 0.301 0.202 0.469 0.238 0.428 0.352 0.781 0.603 0.3469 35 0.282 0.198 0.361 0.256 0.296 0.198 0.462 0.234 0.426 0.351 0.778 0.601 0.3146 28 0.277 0.194 0.354 0.252 0.290 0.195 0.454 0.230 0.425 0.349 0.775 0.597 0.2779 21 0.272 0.190 0.348 0.248 0.285 0.191 0.447 0.226 0.423 0.348 0.772 0.594 0.2413 14 0.267 0.187 0.342 0.244 0.280 0.188 0.439 0.222 0.421 0.346 0.769 0.591 0.2046 0.262 0.183 0.336 0.241 0.276 0.184 0.432 0.219 0.419 0.345 0.765 0.587 0.1679 0.257 0.180 0.330 0.238 0.271 0.181 0.424 0.215 0.417 0.343 0.761 0.583 Ban5_ SCN1 78 Ban5_ SCN3 Ban9_ SCN3 Trang5_ SCN3 Trang9_ SCN3 Annex 4: Hs in scenarios in which density of mangrove forest varies Depth (m) Botlev (m) Distance (m) No mangrove 1600 tree/ha 2000 tree/ha 2500 tree/ha Hs (m) 3000 tree/ha 3500 tree/ha 4000 tree/ha 4500 tree/ha 5000 tree/ha 3.7271 0.6237 399 1.55423 1.56581 1.56581 1.56108 1.56105 1.56361 1.56361 1.56581 1.56581 3.7273 0.6238 392 1.55265 1.56396 1.56397 1.55914 1.55912 1.56169 1.56169 1.56397 1.56396 3.7276 0.624 385 1.55113 1.56222 1.56223 1.55732 1.55732 1.55991 1.55991 1.56223 1.56222 3.7289 0.6252 378 1.5497 1.56066 1.56066 1.55567 1.55567 1.5583 1.5583 1.56066 1.56066 3.732 0.6282 371 1.54848 1.55926 1.55926 1.55418 1.55418 1.55687 1.55687 1.55926 1.55926 3.7351 0.6312 364 1.54739 1.55803 1.55801 1.55285 1.55286 1.55558 1.55558 1.55801 1.55803 3.7382 0.6342 357 1.54646 1.55695 1.55692 1.55168 1.55168 1.55444 1.55444 1.55692 1.55694 3.7412 0.6372 350 1.54563 1.51974 1.51113 1.49502 1.48421 1.47756 1.46768 1.46075 1.45135 3.7444 0.6403 343 1.54486 1.4743 1.45542 1.42634 1.40309 1.38589 1.36542 1.34827 1.32911 3.7474 0.6433 336 1.54416 1.42899 1.40024 1.35964 1.32545 1.29886 1.26916 1.24321 1.2158 3.7505 0.6463 329 1.54353 1.38619 1.34878 1.2988 1.25541 1.22095 1.1837 1.15072 1.11694 3.7535 0.6493 322 1.54301 1.34649 1.30185 1.24409 1.19297 1.15213 1.10902 1.07092 1.03326 3.7566 0.6523 315 1.54259 1.30997 1.25924 1.1948 1.13725 1.09158 1.04464 1.00398 0.96428 3.7595 0.6552 308 1.54223 1.27642 1.22039 1.15021 1.08741 1.03877 0.98974 0.9478 0.90659 3.7623 0.6579 301 1.54189 1.24548 1.18481 1.10968 1.04297 0.99302 0.94267 0.90013 0.85806 3.7649 0.6605 294 1.54158 1.21682 1.15202 1.07296 1.0036 0.95321 0.90197 0.85928 0.81705 3.7676 0.6632 287 1.54132 1.1902 1.1218 1.03975 0.96891 0.91833 0.86675 0.82407 0.78224 79 Depth (m) Botlev (m) Distance (m) No mangrove 1600 tree/ha 2000 tree/ha 2500 tree/ha Hs (m) 3000 tree/ha 3500 tree/ha 4000 tree/ha 4500 tree/ha 5000 tree/ha 3.7703 0.6659 280 1.54108 1.16536 1.09391 1.00975 0.93813 0.88756 0.83588 0.7937 0.75236 3.7705 0.666 273 1.54079 1.14214 1.06832 0.98273 0.91086 0.86041 0.8089 0.76722 0.72667 3.7665 0.662 266 1.54041 1.12045 1.04507 0.95828 0.88646 0.83631 0.78509 0.74433 0.70459 3.7625 0.658 259 1.54 1.10029 1.02391 0.93605 0.86451 0.81479 0.76414 0.72435 0.68553 3.7586 0.6541 252 1.53959 1.08153 1.00453 0.91587 0.8447 0.79548 0.74565 0.70687 0.66921 3.7546 0.6501 245 1.53915 1.06407 0.98667 0.89742 0.82678 0.77814 0.72931 0.69174 0.65519 3.7496 0.645 238 1.53863 1.04779 0.97018 0.8804 0.81061 0.76256 0.71488 0.6784 0.64297 3.7428 0.6382 231 1.53803 1.03261 0.95487 0.86471 0.79596 0.74868 0.70191 0.66693 0.63253 3.736 0.6314 224 1.53734 1.01838 0.94058 0.85038 0.78252 0.7362 0.6901 0.65683 0.62365 3.7292 0.6246 217 1.53659 1.00503 0.92727 0.83717 0.77016 0.72486 0.67966 0.64807 0.6163 3.7225 0.6178 210 1.53577 0.99247 0.91492 0.82502 0.75866 0.71463 0.67028 0.6401 0.61037 3.7156 0.6109 203 1.53482 0.98061 0.90333 0.81374 0.74803 0.70531 0.6621 0.63297 0.60515 3.7085 0.6038 196 1.5337 0.96945 0.89247 0.8032 0.73823 0.69687 0.6548 0.62655 0.60057 3.7014 0.5966 189 1.53245 0.95889 0.88225 0.79334 0.72919 0.68906 0.64834 0.62085 0.59635 3.6943 0.5895 182 1.53115 0.94895 0.87259 0.78405 0.72083 0.68183 0.64256 0.61596 0.59254 3.6873 0.5824 175 1.5298 0.93958 0.86343 0.77536 0.71309 0.67513 0.63742 0.61171 0.58901 3.6801 0.5752 168 1.5284 0.93072 0.85472 0.76726 0.7059 0.66885 0.63263 0.60802 0.58568 3.6729 0.5679 161 1.52692 0.92232 0.8465 0.75965 0.69922 0.66303 0.62805 0.60447 0.5828 3.6657 0.5607 154 1.52537 0.9143 0.83872 0.75249 0.69309 0.65765 0.62361 0.60107 0.58028 80 Depth (m) Botlev (m) Distance (m) No mangrove 1600 tree/ha 2000 tree/ha 2500 tree/ha Hs (m) 3000 tree/ha 3500 tree/ha 4000 tree/ha 4500 tree/ha 5000 tree/ha 3.6585 0.5534 147 1.52376 0.90669 0.83135 0.7457 0.68745 0.65271 0.61941 0.59794 0.57779 3.6512 0.5461 140 1.52208 0.89948 0.82438 0.73933 0.68211 0.64819 0.61547 0.59493 0.57542 3.6453 0.5401 133 1.5204 0.89261 0.81774 0.73334 0.67709 0.64404 0.61178 0.59202 0.57321 3.6413 0.536 126 1.51872 0.88599 0.81145 0.72771 0.6724 0.64022 0.60829 0.58925 0.57099 3.6373 0.5319 119 1.51703 0.87969 0.80547 0.72247 0.668 0.63658 0.60506 0.58655 0.56877 3.6332 0.5278 112 1.51535 0.87366 0.79981 0.7176 0.66386 0.63317 0.60207 0.58393 0.56652 3.6291 0.5236 105 1.51365 0.86788 0.79449 0.71306 0.66001 0.62998 0.59934 0.58146 0.5643 3.6231 0.5175 98 1.51191 0.86229 0.78944 0.70883 0.65644 0.62688 0.59679 0.57904 0.56215 3.6141 0.5084 91 1.51004 0.85693 0.78464 0.70484 0.65306 0.62393 0.59431 0.57667 0.56001 3.605 0.4993 84 1.50816 0.85176 0.78002 0.70095 0.64979 0.62117 0.59192 0.57447 0.55785 3.596 0.4902 77 1.50623 0.84674 0.77554 0.6972 0.64662 0.61856 0.58957 0.57238 0.55569 3.587 0.4811 70 1.50429 0.84191 0.77123 0.69358 0.64364 0.61608 0.58729 0.57031 0.55351 3.5699 0.464 63 1.5021 0.83722 0.76708 0.69005 0.64088 0.61379 0.58505 0.56824 0.55134 3.5406 0.4347 56 1.49945 0.83265 0.76306 0.68661 0.63827 0.61146 0.58284 0.56614 0.54929 3.5115 0.4055 49 1.49648 0.82816 0.7591 0.68323 0.63567 0.6091 0.58064 0.56399 0.54718 3.4822 0.3762 42 1.49314 0.82374 0.75519 0.67988 0.63307 0.60669 0.57843 0.56183 0.54491 3.453 0.3469 35 1.48944 0.81937 0.75127 0.67657 0.63053 0.60428 0.57626 0.55967 0.54258 3.4208 0.3146 28 1.48523 0.81509 0.74742 0.67328 0.62802 0.60188 0.57419 0.55743 0.54018 3.3842 0.2779 21 1.48039 0.81084 0.74362 0.67005 0.62556 0.59948 0.57209 0.55515 0.53771 81 Depth (m) Botlev (m) Distance (m) No mangrove 1600 tree/ha 2000 tree/ha 2500 tree/ha Hs (m) 3000 tree/ha 3500 tree/ha 4000 tree/ha 4500 tree/ha 5000 tree/ha 3.3478 0.2413 14 1.47498 0.80664 0.73988 0.6669 0.62308 0.59707 0.56988 0.55286 0.53523 3.3113 0.2046 1.46896 0.8025 0.73623 0.66375 0.62053 0.59462 0.56764 0.55054 0.53277 3.2748 0.1679 1.46169 0.79842 0.73267 0.66069 0.61792 0.59214 0.56532 0.54817 0.53033 82 Annex 5: Hs in Scenarios with and without climate change Distance (m) Hs (m) SE monsoon 399 392 385 378 371 364 357 350 343 336 329 322 315 308 301 294 287 280 273 266 259 252 245 238 231 224 217 210 203 196 189 182 175 168 161 154 0.55068 0.55011 0.54952 0.54889 0.5482 0.54748 0.54675 0.53296 0.51559 0.49779 0.4806 0.4643 0.44894 0.43447 0.42082 0.40793 0.39574 0.3842 0.37329 0.36296 0.35314 0.34376 0.33482 0.3263 0.31816 0.31037 0.30291 0.29576 0.2889 0.28231 0.27598 0.2699 0.26405 0.25841 0.25299 0.24776 SE monsoon with CL change 0.60884 0.60842 0.60799 0.60753 0.60703 0.60652 0.606 0.59135 0.57273 0.55356 0.53496 0.51725 0.5005 0.48467 0.4697 0.45555 0.44214 0.42943 0.41741 0.40603 0.3952 0.38488 0.37503 0.36564 0.35668 0.34811 0.33989 0.33201 0.32445 0.31718 0.31021 0.3035 0.29704 0.29083 0.28484 0.27907 NE monsoon 0.65424 0.65398 0.65372 0.65346 0.65318 0.65291 0.65266 0.63635 0.61554 0.59403 0.57311 0.55318 0.53432 0.51653 0.49976 0.48394 0.46899 0.45485 0.44149 0.42883 0.4168 0.40535 0.39445 0.38406 0.37415 0.36469 0.35563 0.34696 0.33866 0.33071 0.32309 0.31577 0.30875 0.302 0.29552 0.28928 83 NE monsoon with CL change 0.68503 0.68485 0.68468 0.68452 0.68436 0.6842 0.68405 0.66796 0.64733 0.62593 0.60504 0.58507 0.56613 0.5482 0.53124 0.51519 0.5 0.48559 0.47192 0.45896 0.4466 0.43482 0.42357 0.41284 0.40258 0.39277 0.38336 0.37435 0.36571 0.35742 0.34945 0.3418 0.33445 0.32738 0.32058 0.31403 Storm 1.56108 1.55914 1.55732 1.55567 1.55418 1.55285 1.55168 1.49502 1.42634 1.35964 1.2988 1.24409 1.1948 1.15021 1.10968 1.07296 1.03975 1.00975 0.98273 0.95828 0.93605 0.91587 0.89742 0.8804 0.86471 0.85038 0.83717 0.82502 0.81374 0.8032 0.79334 0.78405 0.77536 0.76726 0.75965 0.75249 Storm with CL change 1.67936 1.67753 1.67582 1.67423 1.6728 1.6715 1.67034 1.61053 1.538 1.46731 1.40256 1.34402 1.29097 1.2426 1.19835 1.15796 1.12122 1.08787 1.05762 1.03012 1.00502 0.98216 0.96123 0.94201 0.92424 0.90784 0.89266 0.87859 0.8656 0.85358 0.84235 0.83182 0.82195 0.81277 0.80418 0.79606 Distance (m) Hs (m) SE monsoon 147 140 133 126 119 112 105 98 91 84 77 70 63 56 49 42 35 28 21 14 0.24271 0.23784 0.23313 0.22856 0.22416 0.2199 0.21578 0.21182 0.20801 0.20431 0.20071 0.19722 0.1939 0.19076 0.18769 0.18467 0.1817 0.17882 0.17603 0.17329 0.17058 0.168 SE monsoon with CL change 0.2735 0.26813 0.26293 0.2579 0.25304 0.24835 0.24381 0.23944 0.23522 0.23113 0.22717 0.22331 0.21962 0.21612 0.21269 0.20933 0.20603 0.20282 0.19971 0.19664 0.19363 0.19077 NE monsoon 0.28327 0.27748 0.2719 0.2665 0.26131 0.25629 0.25145 0.24679 0.2423 0.23794 0.23373 0.22963 0.2257 0.22195 0.21828 0.21469 0.21117 0.20775 0.20444 0.20118 0.19799 0.19495 84 NE monsoon with CL change 0.30772 0.30163 0.29576 0.29009 0.28461 0.27933 0.27422 0.2693 0.26454 0.25993 0.25546 0.25113 0.24695 0.24293 0.23901 0.23517 0.23142 0.22776 0.22421 0.22072 0.21731 0.21405 Storm 0.7457 0.73933 0.73334 0.72771 0.72247 0.7176 0.71306 0.70883 0.70484 0.70095 0.6972 0.69358 0.69005 0.68661 0.68323 0.67988 0.67657 0.67328 0.67005 0.6669 0.66375 0.66069 Storm with CL change 0.78841 0.78121 0.77442 0.76803 0.76205 0.75642 0.75118 0.74634 0.74186 0.7376 0.73353 0.72954 0.72569 0.72198 0.71839 0.71483 0.71126 0.70772 0.70428 0.701 0.69782 0.69466 Annex 6: Some photos from the field trip Figure A.1 Journey of the field trip in mangrove forest in Hau Loc Figure A.2 Magroves forest in Hau Loc 85 Figure A.3 Wild young mangroves in Hau Loc Figure A.4 Planted Magroves forest in Hau Loc 86 Figure A.5 Features of S.caseolaris Figure A.6 Features of K.obovata 87 Figure A.7 Measure of parameters of tree Figure A.8 Carrying the young 2.5 year old K.obovate to plant in the field 88 Figure A.9 Sea dyke system in Hau Loc Figure A.10 Data collection in Hau Loc Agriculture and Rural Department 89 ... characteristics of mangrove species 1.1.1 Sonneratia caseolaris (Vietnamese name: Cây Bần chua) 1.1.2 Kandelia obovata (Vietnamese name: Trang) 1.2 The mechanism of wave attenuation through... Hoang Tan Vietnam [17] caseolaris, S ,Tien 14 Lang, Hai griffithii, and Can Gio Aegiceras corniculatum, Avicennia marina, Kandelia candel Nguyen Nghiên cứu khả hấp 2012 Kendelia Nam Dinh, candel,... Vietnam There are some studies about wave attenuation by mangrove forest in Vietnam which is shown in Table 1.1 13 Table 1.1 Some studies about wave attenuation by mangrove forest in Vietnam