Luận văn analysis of boundary conditions and concept design for port dong lam thua thien hue province vietnam

40 Figure 32: cumulative probability of exceedance versus wave height for offshore and nearshore wave data.. 94 Figure 68: sediment transport during monsoon and typhoon events - offsho

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DESIGN FOR PORT DONG LAM, THUA THIEN-HUE

PROVINCE, VIETNAM"

Prof Ir H Ligteringen Delft University of Technology W.A.Broersen

Dr Ir J Van de Graaff Delft University of Technology

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PREFACE

What lies in front of you is the result of the Master Thesis, the final step before graduation

in Civil Engineering at Delft University of Technology (DUT) This project is about the

analysis and modelling of boundary conditions and the conceptual design of Port Dong Lam,

Thua Thien-Hue Province, Vietnam The work was executed in cooperation with Royal

Haskoning - departments Rotterdam, The Netherlands and Ho Chi Minh City, Vietnam

Royal Haskoning provided me a working space and put all their information, knowledge and

advice at my disposal, for which I am thankful As well, I want to show my gratefulness to

the members of my graduation committee for guiding me during the process:

Prof ir H Ligteringen Delft University of Technology, chair Ports & Waterways

Dr ir J Van de Graaff Delft University of Technology, chair Coastal Engineering

Ir D.J.R Walstra Delft University of Technology, chair Coastal Engineering

Besides I want to thank my overseas supervisors in Vietnam for providing information and

advice:

Last but not least I want to show my appreciation to my friends, roommates and fellow

students Special thanks go to my family, Mischa and my close friends Loek, Paul, Cyriel and

Jan Without their support the mountain to climb would have been a few steps higher

At the end of this project I can say that I have really expanded my knowledge and skills,

both technically and pragmatically Moreover, my self-awareness has reached a higher level

which is priceless with regard to my future The struggle to achieve this was tough and I

would like to quote a fellow student to describe this journey:

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Laat ik het afstudeerwerk vergelijken met een tocht over de Andes van Chili naar Argentinië

Vooraf lijkt het een prachtig mooie tocht te worden, het begin loopt relaxed, maar er komt

ongetwijfeld een pas waar niet overheen te komen is Dagen van sneeuwstormen en

psychologische ellende zorgen ervoor dat we geen steek verder komen Maar naarmate het

berglandschap bekender terrein wordt, worden nieuwe paden zichtbaar Met de weinige

ervaring stuiten we nog op een aantal tegenslagen die we van tevoren niet hadden

voorzien, maar omdat we goede bagage hebben en een portie kennis over de elementen

lukt het ons met gezond verstand om een weg te banen door de Cordilleras

(Andesgebergte) Aangekomen in Argentinië staat vervolgens een vliegtuig klaar, die kun je

nemen, naar welke plek op aarde dan ook Bas van Son (2009)

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SUMMARY

Introduction

Dong Lam Cement Factory is developing a new clinker plant in Thua Thien-Hue Province,

Vietnam The clinker has to be exported towards Ho Chi Minh City, where it is grinded into

cement and used for the construction industry For the clinker production coal is needed

and has to be imported To make the in- and export possible a new dedicated seaport is

required to allow for 15,000 dwt clinker vessels and 7,000 dwt coal vessels

From the production plant, the clinker bulk is transported to a storage facility by truck

From here the material is transported to the seaport by means of a conveyor belt The coal

is transported by the same modalities but vice versa

In the first phase (up to 2015) about 2 million ton per year bulk material is expected to be

handled at this port In the second phase (2015 - 2035) this amounts about 4 million ton per

year of bulk material Following the increasing demand for concrete, a doubling of the

production is expected in 2035 This results in a throughput of almost 8 million ton per year

in the third project phase (2035 and up)

Objective

The objective is to design a port with sufficient capacity to handle the predicted cargo flow

and which offers acceptable conditions for the ships to enter The effective berth and

hinterland capacity have to be determined such, that turnaround times are within limits To

create safe conditions, the vessels need to have enough space for manouevring in the wet

port area These manoeuvres can be seriously disturbed by wind, wave, currents and

siltation on the long term To ensure the workability of the port these effects have to be

limited

Analysis

Port capacity

To determine the effective berth capacity the queuing theory is applied In phase 1 and 2

one clinker and one coal berth satisfy with effective capacities of respectively 700 and 175

t/h respectively In phase 3 two clinker and two coal berths are needed with the same

loading/unloading rates Clinker is loaded with a radial loader and coal is unloaded with a

pneumatic unloader

Boundary conditions

To get insight in the environmental boundary conditions, field data is collected and

analysed thoroughly In Vietnam the wind climate is governed by the South-East Asian

monsoon system, with a dominant SE direction and strong NNE winds The wave climate is

directly influenced by the wind climate and shows a similar pattern With regard to extreme

conditions, once a year a tropical storm lands in the vicinity of the port site These storms

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Having frequent waves from the NNE and SE, littoral transport is generated in north- and

southward direction Nevertheless, the northward transport is clearly dominant Currents

are heading SE for most of the time

Port dimensions

To reduce the breakwater length, it is decided for the tugs to make fast outside the

breakwaters As a consequence, almost 4% of downtime can be expected, since tugs cannot

operate when Hs ≥ 2m Once the vessel has entered the harbour the stopping manoeuvre

can be started, which requires an inner channel length of 290 m The turning circle allows

for the turning manoeuvre for which a radius of 290 m is reserved In the mooring basin,

ships are forced into the right position to make safe berthing possible This requires a width

of 210 m and a quay length of 652 m Note that these basic dimensions are determined for

project phase 3 (4 berths), considering a 15,000 dwt design vessel

Layouts and evaluation

Four different layouts are developed for phase 3 of the project Two of them are dismissed

in an early stage, because of unfavourable conditions The other two layouts – the 'coastal'

and 'offshore' alternative, are evaluated with a cost-value approach In this approach the

value of each design is assessed by means of a MCA

The following criteria are taken into consideration: navigation, tranquillity at berth, coastal

impact, sedimentation, ease of cargo handling, safety and flexibility Regarding navigation

and wind, wave and current hindrance, no significant differences are found It turns out

that the most important difference is found in the coastal impact The coastal alternative

will cause erosion along 7.5 km of coastline with a maximum retreat of 100 m Instead, the

offshore alternative affects 'only' 3 km with maximum retreat of 70 m

The other element of the cost-value approach is the costs The investment costs for the

coastal alternative are 64.1 M$, which include the dredging works, breakwater and quay

construction The costs for the offshore port amount 77.5 M$, which entails the dredging

works, breakwater, jetty quay and trestle construction The relative low costs for the

coastal alternative are achieved by applying the cut-and-fill balance; the dredged sand is

used as breakwater foundation Maintenance dredging costs are 1.75 M$ and 0.9 M$ for

respectively the coastal and offshore alternative

To finish the cost-value approach the value/costs ratio is taken for both port layouts The

coastal alternative (1.11) turns out to be a better port layout than the offshore alternative

(0.95)

Downtime assessment

The total downtime amounts 5.4 %, which is entails the following contributions:

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Figure 95: final port design

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CONTENTS

PREFACE I

SUMMARY III

TABLE OF FIGURES XI

TABLE OF TABLES XV

TABLE OF EQUATIONS XVII

1 INTRODUCTION 3

1.1 S TUDY B ACKGROUND 3

1.1.1 Port location 4

1.1.2 Metocean conditions 4

1.2 S TUDY S COPE 5

1.3 S TUDY APPROACH AND CONTENTS 6

1.3.1 Data collection 6

1.3.2 Modelling 6

1.3.3 Transport capacities 6

1.3.4 Port dimensions 6

1.3.5 Layout design and concept selection 6

1.4 M ISCELLANEOUS 7

2 ENVIRONMENTAL BOUNDARY CONDITIONS 8

2.1 I NTRODUCTION 8

2.2 C OASTAL CHARACTERISTICS 8

2.3 C LIMATE 8

2.4 T OPOGRAPHY 9

2.5 B ATHYMETRY 10

2.5.1 Cross-shore profile 11

2.6 W ATER LEVELS 12

2.6.1 Tide 12

2.6.2 Water level setup 13

2.6.3 Sea level rise 18

2.6.4 Conclusion 18

2.7 W IND DATA 19

2.7.1 Background 19

2.7.2 Normal conditions 20

2.7.3 Extreme conditions 25

2.7.4 Conclusion 27

2.8 W AVE DATA OFFSHORE 28

2.8.3 Conclusion 37

2.9 W AVE DATA NEARSHORE 38

2.9.3 Conclusion 46

2.10 C URRENT DATA 48

2.10.1 Wind-driven currents 49

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2.10.3 Conclusion 50

2.11 S EDIMENT CHARACTERISTICS 52

2.12 C OASTAL MORPHOLOGY 55

2.12.1 TUNG (2001) 55

2.12.2 Littoral transport under normal conditions 56

2.12.3 Littoral transport under extreme conditions 58

2.13 S OIL CONDITIONS 62

3 TRANSPORT CAPACITY 65

3.1 T HROUGHPUT 65

3.2 O PERATIONAL R EQUIREMENTS 68

3.3 T RANSPORT C APACITIES 69

3.3.1 Berth assessment 69

3.3.2 Conveyor belt 74

3.3.3 Storage area 75

3.3.4 Road 78

3.3.5 Conclusion 78

4 BASIC PORT DIMENSIONS 79

4.1 I NTRODUCTION 79

4.2 N ORMAL CONDITIONS 79

4.3 D ESIGN VESSEL 79

4.4 W ATER AREA 80

4.4.1 Approach channel 80

4.4.2 Turning Circle 85

4.4.3 Mooring Basin 86

4.4.4 Quay length 86

4.5 C ONCLUSION 87

5 ALTERNATIVE LAYOUTS 88

5.1 I NTRODUCTION 88

5.2 D ESIGN CONSIDERATIONS 88

5.3 P ORT LAYOUTS 90

5.3.1 Refinement of port layouts 91

5.4 M ULTI - CRITERIA ANALYSIS 96

5.4.1 Navigation 97

5.4.2 Tranquility at berth 97

5.4.3 Coastal impact 100

5.4.4 Sedimentation 105

5.4.5 Safety 108

5.4.6 Flexibility 109

5.4.7 Result 109

5.5 C APITAL COSTS CALCULATION 111

5.5.1 Coastal port 111

5.5.2 Offshore port 119

5.6 M AINTENANCE COSTS CALCULATION 126

5.6.1 Coastal port 126

5.6.2 Offshore port 126

5.7 C OST -V ALUE APPROACH 128

6 CONCLUSIONS AND RECOMMENDATIONS 129

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6.1 C ONCLUSIONS 129

6.2 R ECOMMENDATIONS 130

6.2.1 Data and modelling 130

6.2.2 Port design 130

7 REFERENCES 131

7.1 B OOKS 131

7.2 L ECTURE N OTES 131

7.3 A RTICLES 131

7.4 O THER REPORTS 131

7.5 M ANUALS 131

A MONSOON AND TYPHOON BACKGROUND 134

A.1 M ONSOONS 134

A.2 T YPHOONS 134

B OTHER WIND AND WAVE SOURCES 136

B.1 W IND DATA FROM C ON C O I SLAND 136

B.2 W AVE DATA FROM C ON C O I SLAND 137

B.3 W AVE DATA FROM G LOBAL W AVE S TATISTICS 138

C TYPHOON GENERATED WIND AND WAVES 138

C.1 W IND 138

C.2 W AVES 141

C.2.1 Calculation of maximum wave heights 141

C.2.2 Calculation of wave heights at port site 143

C.2.3 Example calculation 146

D EXTREME VALUE DISTRIBUTIONS 149

D.1 E XTREME WIND SPEEDS 149

D.2 E XTREME WAVE HEIGHTS – TYPHOON GENERATED 150

D.3 E XTREME WAVE HEIGHTS – MONSOON GENERATED 152

E OFFSHORE CURRENTS 155

E.1 W IND - DRIVEN 155

E.2 T IDE - DRIVEN 156

F WAVE MODELLING 157

F.1 G ENERAL 157

F.2 M ODEL SETUP 157

F.2.1 Land boundary 157

F.2.2 Computational grids 158

F.2.3 Bathymetry 159

F.3 M ODEL INPUT 159

F.3.1 Hydrodynamic boundary conditions 160

F.3.2 Physical parameters 161

F.3.3 Numerical parameters 162

F.4 C ALIBRATION AND VALIDATION 162

F.5 M ODEL OUTPUT 162

F.5.1 Normal conditions 162

F.5.2 Extreme conditions 165

G MORPHOLOGICAL MODELLING 167

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G.2 CERC FORMULA 167

G.2.1 General 167

G.2.2 Calculation setup 169

G.2.3 Calculation of wave parameters 169

G.2.4 Calculation of shoaling and refraction factors 169

G.2.5 Calculation of sediment transport 170

G.2.6 Calculation input and output 170

G.3 MIKE LITPACK – LITDRIFT 173

G.3.1 General 173

G.3.2 Hydrodynamic model 173

G.3.3 Sediment transport model 173

G.3.4 Model setup 174

G.3.5 Model settings 177

G.3.6 Model input 178

G.3.7 Calibration and validation 179

G.3.8 Model output 179

G.3.9 Sensitivity analysis 183

G.4 MIKE LITPACK – LITLINE 185

G.4.1 General 185

G.4.2 Model setup 185

G.4.3 Model input 187

G.4.4 Calibration and validation 189

G.4.5 Model output 189

H CALCULATIONS ON BERTH CAPACITY 190

H.1 P HASE 1 190

H.2 P HASE 2 191

H.3 P HASE 3 192

I BREAKWATER CALCULATIONS 193

I.1 C OASTAL PORT 193

I.2 O FFSHORE PORT 195

J DREDGING COSTS 196

J.1 C APITAL DREDGING COSTS 196

J.2 M AINTENANCE DREDGING COSTS – COASTAL PORT 197

J.3 M AINTENANCE DREDGING COSTS – OFFSHORE PORT 198

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TABLE OF FIGURES

Figure 1: planned port site in Google Earth image 3

Figure 2: transport system for clinker export and coal import 4

Figure 3: rivers and lagoon system in Thua Thie- Hue province 9

Figure 4: bathymetry near Thua Thien-Hue Province obtained from C-map 10

Figure 5: bathymetry near port site obtained from C-map 10

Figure 6: cross-shore C-C' 11

Figure 7: different water levels in a mixed tide 12

Figure 8: measurement of the water level at the project site 13

Figure 9: schematization of wind setup 15

Figure 10: schematization of the fetch for wind-setup calculation 15

Figure 11: schematization of wave setup 17

Figure 12: calculation of wave setup 17

Figure 13: extreme water level contributions 18

Figure 14: Asian summer and winter monsoon system 19

Figure 15: typhoon Cecil, landed in Vietnam at the 15th of October, 1985 20

Figure 16: wind climate according to the China Sea Pilot 21

Figure 17: NOAA wind roses for the six data locations 22

Figure 18: wind rose (1) 23

Figure 19: time series of wind speed in 1998 24

Figure 20: cumulative exceedance frequency versus wind speed 25

Figure 21: top 50 of tropical depressions hitting central Vietnam between 1959 and 2009 26

Figure 22: NOAA wave roses for the six data locations 29

Figure 23: time series of wave height in 1998 30

Figure 24: wave rose (wave height, direction and frequency) 31

Figure 25: wave rose (wave period, direction and frequency) 32

Figure 26: wave height versus frequency exceedance 33

Figure 27: Hs - Tp relation 34

Figure 28: severe monsoon event in dec 1998 36

Figure 29: wave model result for random wave condition 38

Figure 30: offshore wave rose with schematized wave directions Source: NOAA, location 18N;107.5E 39

Figure 31: nearshore wave rose at 15 m water depth 40

Figure 32: cumulative probability of exceedance versus wave height for offshore and nearshore wave data 41

Figure 33: Typhoon ED (1990) coming from ESE (112.5º) direction and showing the dominant wave front 43

Figure 34: currents in the South China Sea Source: UKHO (1978) 48

Figure 35: locations of current measurements (about 600 m offshore) Source: TEDIPORT 49

Figure 36: current rose for vertical 2 Source: local measurement by TEDIPORT 50

Figure 37: hydrographical survey area (drawing scale 1 : 50,000) 52

Figure 38: bed sample of location MD9 53

Figure 39: net sediment transports along the coastal barrier from Thuan An inlet to Linh Thai 55

Figure 40: cross-shore distribution of sediment transport for 1/10 years typhoon condition 59

Figure 41: cross-shore distribution of sediment transport for 1/50 years typhoon condition 59

Figure 42: cross-shore distribution of sediment transport for 1/10 years monsoon condition 59

Figure 43: cross-shore distribution of sediment transport for 1/50 years monsoon condition 59

Figure 44: borehole locations for geotechnical survey 62

Figure 45: geotechnical cross-section indicating four different soil layers 63

Figure 46: throughput time scheme 65

Figure 47: transport system to and from the new sea port 66

Figure 48: schematized port system and the Erlang-k distribution 70

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Figure 50: example of a radial loader for clinker loading 72

Figure 51: example of a continuous unloader for coal unloading 73

Figure 52: example of a stacker-reclaimer 73

Figure 53: example of a conveyor belt (non-enclosed) 74

Figure 54: triangular shape of storage areas 75

Figure 55: example of an open storage 76

Figure 56: example of a covered warehouse 76

Figure 57: road between production plant and Port Dong Lam 78

Figure 58: make fast and pilot boarding outside the breakwater 81

Figure 59: increase of drift angle during entering of the port 82

Figure 60: basic manoeuvring width of a sailing ship 83

Figure 61: channel depth contributions 85

Figure 62: required space for operations in mooring basin 86

Figure 63: four port layouts 91

Figure 64: cross-shore distribution of sediment transport during 1/10 years typhoon 92

Figure 65: sediment transport during typhoon event - coastal port 92

Figure 66: sediment transport during monsoon event - coastal port 93

Figure 67: cross-shore distribution of sediment transport during 1/10 years monsoon 94

Figure 68: sediment transport during monsoon and typhoon events - offshore port 94

Figure 69: diffraction around breakwater head – coastal port 98

Figure 70: diffraction around breakwater head – offshore port 99

Figure 71: coastal impact - coastal port 100

Figure 72: coastal erosion - coastal port 102

Figure 73: coastal impact - offshore port 103

Figure 74: coastal erosion - offshore port 104

Figure 75: siltation areas for coastal port 105

Figure 76: cross-shore sediment distribution during 1/10 monsoon storm without and with coastline growth 106 Figure 77: siltation area for offshore port 108

Figure 78: possible port expansion - coastal port 109

Figure 79: dredging works - coastal port 111

Figure 80: sand spit and land reclamation – coastal port 112

Figure 81: cross-section of sand spit 112

Figure 82: erosion profile for sandy beaches 113

Figure 83: longitudinal cross-section of the main breakwater (lower picture) and the secondary breakwater (upper picture) 114

Figure 84: wave heights and water depths from SWAN model – coastal port 115

Figure 85: cross-section 1 and 2 (founded on sand spit) – coastal port 116

Figure 86: cross-sections 3 and 4 – coastal port 116

Figure 87: example of a marginal quay 119

Figure 88: dredging works - offshore port 120

Figure 89: sand spit - offshore port 120

Figure 90: longitudinal cross-section of offshore breakwater 121

Figure 91: wave heights and water depths from SWAN model - offshore port 122

Figure 92: cross-sections 1 and 2 - offshore port 123

Figure 93: example of a jetty quay, connected to the land by a trestle 125

Figure 94: cost estimate offshore port 125

Figure 95: final port design 129

Figure 96: Asian summer and winter monsoon system 134

Figure 97: wind rose Source: HMS, Con Co Island 136

Figure 98: wave rose Source: HMS of Con Co Island 137

Figure 99: tabular wave data from Global Wave Statistics, Northeast direction 138

Figure 100: top 50 of tropical depressions hitting central Vietnam between 1959 and 2009 139

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Figure 102: F/R' versus Umax (m/s) 142

Figure 103: ratio of wave height at distant r to wave height at eye radius R 144

Figure 104: determination of distant r between landfall and port site 145

Figure 105: definition of X, X' and Y 145

Figure 106: example calculation: determination of Hr / HR 148

Figure 107: Weibull distribution fitted to wind speeds of 33 m/s and up 150

Figure 108: distinction between tropical storms and typhoons 151

Figure 109: Weibull distribution fitted to wave heights of 6.61 m and up 152

Figure 110: Weibull fitted to wave height of 3.3 m and up 154

Figure 111: currents in the South China Sea Source: UKHO (1978) 155

Figure 112: computational grids used in the SWAN model 158

Figure 113: land boundary, computational grid and bathymetry for grid 1 159

Figure 114: k-factor per wave height and direction 164

Figure 115: grid 2 and its bathymetry 164

Figure 116: wave attenuation for wave condition 20, grid 2 165

Figure 117: grid 1 (most coarse) in modelling of extreme waves 166

Figure 118: wave power P per unit beach length (left) and the alongshore component of P (right) 168

Figure 119: linear relation between Sx (Il ) and P (Pl ) based on measurements 168

Figure 120: bathymetric survey by TEDIPORT 175

Figure 121: cross-shore coastal profile 175

Figure 122: fall velocity by Van Rijn (1984) and Delft Hydraulics 177

Figure 123: measured and approximated tidal current velocity 179

Figure 124: measured and approximated water level 179

Figure 125: wave height, wave period and sediment transport in 1998 181

Figure 126: wave height, wave period and sediment transport (m3/s) between 1997 and 2009 182

Figure 127: accumulated sediment transport (m3) from 1997 to 2009 183

Figure 128: results of the sensitivity analysis 184

Figure 129: LITLINE model setup with indicated boundary conditions 186

Figure 130: offshore port schematization 187

Figure 131: coastal port schematization 187

Figure 132: definition of coastline characteristics 188

Figure 133: extended cross-shore profile 189

Figure 134: capital dredging costs 196

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TABLE OF TABLES

Table 1: fetch schematization and wind setup calculation 16

Table 2: wind speed and direction and the corresponding frequencies of occurrence 23

Table 3: typhoon induced wind speeds 27

Table 4: wave height and direction and the corresponding occurrence frequencies 31

Table 5: wave period and direction and the corresponding occurrence frequencies 32

Table 6: wave steepness' for the different wave climates 34

Table 7: typhoon generated extreme waves 35

Table 8: monsoon generated extreme waves 36

Table 9: wave height and direction and the corresponding frequencies of occurrence 41

Table 10: calculation of typhoon wave periods under extreme conditions 42

Table 11: offshore typhoon conditions for wave model 43

Table 12: nearshore typhoon wave conditions for structural design 44

Table 13: nearshore typhoon wave conditions for littoral transport calculation 44

Table 14: calculation of monsoon wave periods under extreme conditions 45

Table 15: offshore monsoon conditions for wave model 45

Table 16: nearshore monsoon wave conditions 45

Table 17: current velocity and the occurrence frequency (%) in vertical 2 Source: TEDIPORT 50

Table 18: sediment characteristics for MD1 to MD17 53

Table 19: total littoral transport per year and per 12 year by CERC formula 57

Table 20: total littoral transport per year and per 12 year as calculated by LITPACK 58

Table 21: input for typhoon induced sediment transport 58

Table 22: input for monsoon induced sediment transport 60

Table 23: determination of coal volume 67

Table 24: occupancy, mean waiting time and mean turnaround time in Phase 1 70

Table 27: required storage areas for clinker storage facility 77

Table 28: required storage areas for coal storage facility 77

Table 29: required number of berths, transport and storage capacities 78

Table 30: characteristics of clinker and coal vessels 80

Table 31: calculation results of channel width 83

Table 32: calculation results of channel depth 84

Table 33: calculation result for inner channel depth 85

Table 34: summary of water area dimensions 87

Table 35: determination of weight factors 96

Table 36: wave diffraction factors for coastal port 98

Table 37: wave diffraction factors for offshore port 99

Table 38: coastline growth in time for coastal port 101

Table 39: coastline growth in time for offshore port 102

Table 40: MCA result 110

Table 41: calculation of sand spit volume 112

Table 42: required volumes of concrete and natural rock – coastal port 117

Table 43: material availability and costs 117

Table 44: placing and total costs per m3 118

Table 45: Costs of Xbloc armour units 118

Table 46: Total costs of breakwaters – coastal port 118

Table 47: cost estimate coastal port 119

Table 48: total costs of breakwater - offshore port 124

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Table 50: NPV maintenance dredging operations - offshore port 127

Table 51: Cost-Value Approach 128

Table 52: wind speed and direction with corresponding occurrence frequencies 136

Table 53: wave height and direction and the corresponding frequencies of occurrence 137

Table 54: top 50 typhoons between 1959 – 2009 and corresponding wind speeds 140

Table 55: top 50 typhoons and corresponding wave heights 143

Table 56: distant r, ratio r/R, ratio Hr/HR, Hs;max and Hs; max_site 146

Table 57: example calculation: characteristics of typhoon Xangsane 147

Table 58: example calculation: results for typhoon Xangsane 147

Table 59: example calculation: actual wave height Hs;site (in m) 148

Table 60: top 10 monsoon storms in terms of wave height 153

Table 61: example of a SWAN wavecon file 160

Table 62: SWAN input and output for offshore - nearshore wave translation 161

Table 63: extreme offshore wave condition 161

Table 64: offshore - nearshore wave translation in normal conditions 163

Table 65: extreme offshore and nearshore condition 165

Table 66: wave height versus period and the corresponding occurrence frequency 171

Table 67: Kr versus wave height and wave period 171

Table 68: Ksh versus wave height and wave period 171

Table 69: nb versus wave height and wave direction 172

Table 70: cb versus wave height and wave direction 172

Table 71: wave height and period and the corresponding littoral transport 172

Table 72: total littoral transport per year and per 12 year calculated by CERC formula 173

Table 73: result of sediment transport for one random event 181

Table 74: total littoral transport per year and per 12 year as calculated by LITPACK 183

Table 75: berth calculation phase 1 190

Table 78: breakwater calculation – coastal port 194

Table 79: breakwater calculation – offshore port 195

Table 80: maintenance dredging costs - coastal port 197

Table 81: maintenance dredging costs - offshore port 198

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TABLE OF EQUATIONS

Equation 1:water level rise due to low atmospheric pressure 14

Equation 2: calculation of wind shear stress and water level gradient 15

Equation 3: Hs - Tm relationship 34

Equation 4: CERC formula 56

Equation 5: basic sediment transport formula 57

Equation 6: formula to calculate v_eff 82

Equation 7: formula to calculate channel width 83

Equation 8: formula to calculate channel depth 84

Equation 9: calculation of quay length for one berth 86

Equation 10: calculation of sedimentation volume 107

Equation 11: calculation of PV (Present Value) 126

Equation 12: Bretschneider equation for maximum wind speed (m/s) in tropical depressions 138

Equation 13: calculation of effective radius 141

Equation 14: Young's equation 141

Equation 15: JONSWAP relationship 141

Equation 16: example calculation: effective radius 147

Equation 17: example calculation: equivalent fetch 147

Equation 18: example calculation: wave height Hs;max (in m) 147

Equation 19: calculation of the probability of exceedance of U10 for the peak-over-threshold approach 149

Equation 20: Calculation of U10 from Weibull equation 150

Equation 21: requirement for deep water wave conditions 166

Equation 22: basic CERC formula 168

Equation 23: explicit CERC formula 168

Equation 24: calculation L0 169

Equation 25: calculation L 169

Equation 26: calculation k 169

Equation 27: calculation c 169

Equation 28: Snel's Law and calculation of phi_b 170

Equation 29: refraction factor 170

Equation 30: conservation of energy in waves 170

Equation 31: shoaling factor 170

Equation 32: calculation Sx 170

Equation 33: calculation dimensionless bed shear stress 174

Equation 34: vertical turbulent diffusion equation 174

Equation 35: suspended sediment transport 174

Equation 36: calculation of fall velocity 176

Equation 37: calculation of kinematic viscosity 176

Equation 38: continuity equation for sediment 185

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REPORT

Analysis of boundary conditions and concept

design for Port Dong Lam, Thua Thien-Hue

Province, Vietnam

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1 INTRODUCTION

1.1 Study Background

Dong Lam Cement Factory – one of the largest privately owned cement companies in

Vietnam - is developing a new clinker plant in Thua Thien-Hue Province As well, three other

shareholders including a bank and other trading companies are involved

Next to the location of the plant there is a limestone quarry which provides the main

ingredient for production process The produced clinker will be exported from the province

and it will require coal for the production To make this possible a new dedicated seaport is

required to allow for up to 15,000 dwt clinker vessels and up to 7,000 dwt coal vessels This

new seaport terminal is to be constructed several kilometres from the quarry plant on the

coastal stretch North West of the city Hue (see Figure 1) In the first phase (up to 2015)

about 2 million ton per year bulk material is expected to be handled at this port In the

second phase (2015 and up) this amounts about 4 million ton per year of bulk material

After 2035 the production of the plant will be doubled, resulting in a throughput of 8

million ton per year

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The clinker bulk will be transported from the plant to a storage facility by truck over a

specially-build new road From there the material is transported to the seaport by means of

a conveyor belt The coal is transported the other way around This is shown in Figure 2

From the port, the clinker is exported to a grinding plant in Ho Chi Minh City, where it is

grinded into cement

The port is to be located on the beginning of a coastal barrier, which is about 30 km away

from Thuan An inlet of the Tam Giang - Cau Hai lagoon – shown in the upper right corner in

Figure 2 This lagoon is located in Thua Thien-Hue province which is one of the six provinces

in the region of the North Central Coast The province borders the Quang Tri Province to

the north, the city of Da Nang to the east, the Quang Nam Province to the south, and the

Xekong Province of Laos to the west

1.1.2 Metocean conditions

In Vietnam, the monsoon system is the governing force of the wind and wave climate

Besides, typhoons find their origin in the Western Pacific Ocean and propagate towards the

Vietnamese coast The most affected areas by typhoons are the coastal provinces of the

North and Central regions This means that wave conditions are strong and that severe

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wave conditions can be expected Together with the sandy beaches this can lead to

significant erosion and accretion, which has to be studied when building port structures

1.2 Study Scope

Paragraph 1 shows that an extensive transport system is required in between the clinker

and grinding plant to enable the transport of clinker and coal bulk In this study the focus is

on the port design, which forms a very important element The design of the conveyor belt

and storage facility is not considered in this study Only the required capacities are

determined

When designing a port four important conditions should be fulfilled:

• The port entrance at the seaside should be safe and well accessible

• The port basins and quays should provide adequate space for manoeuvring and

berthing of the ships

• At the quay sufficient loading and unloading capacity should be available

• The hinterland connections should be efficient and have enough capacity

In Paragraph 1.1.2 it was stated that knowledge and understanding about the metocean

and morphological circumstances in the port surroundings is crucial to make a proper port

design The study objective can be outlined as follows:

To give insight in the structure of this study the objective can be separated into five main

studies:

1 Data collection

2 Modeling of offshore wave conditions to nearshore and modeling of littoral

transport

3 Determination of required port capacity

4 Calculation of basic port dimensions

5 Design of several port layouts and selection of the optimal layout

The objective is to design a port with sufficient capacity to handle the predicted cargo flow

and which offers acceptable conditions for the ships to enter and for the surroundings This

means that wave and current disturbance ánd sedimentation of the harbor basin have to be

limited as well as the morphological impact on the coast

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1.3 Study approach and contents

1.3.1 Data collection

Before any design can be initiated, information has to be known on the coastal,

bathymetric and climate conditions As well data is required about the water level, wind,

waves and currents Moreover, the sediment characteristics and littoral transport have to

be known and quantified to be able to make a proper port design As well, the soil

conditions have to be known for foundation of the structures These data sources can be

found in Paragraph 2.1 to 2.13

To determine the nearshore wave climate, littoral sediment transport and coastal impact,

numerical models will be setup using SWAN and MIKE LITPACK The results from the wave

modelling study form the input for the morphological model In both models, normal and

extreme conditions are considered The results of the wave and morphological model can

be found in Paragraph 2.9 and 2.12 respectively For more details the reader is referred to

Appendices F and G

1.3.3 Transport capacities

Based on the predicted cargo forecasts the required number of ships per year can be

determined From this the number of berths, loading and unloading capacities, conveyor

belt capacity and the storage areas can be calculated This is described throughout

Paragraph 3.1 to 3.3

By means of design guidelines the principal dimensions of the port can be formulated,

taking into consideration the environmental boundary conditions The principal port

dimensions are understood as the approach channel, mooring basin, turning circle and the

quay length These basic dimensions can be found in Paragraph 4.2 to 4.5

1.3.5 Layout design and concept selection

The port layouts are designed based on guidelines in Paragraph 5.2 and 5.3 The following

elements are considered:

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Based on the cost and value of the different layouts, the best layout is selected To assess

the value of the different layouts, a MCA analysis is done in Paragraph 5.4 and takes the

following aspects into account:

In Paragraphs 5.5 and 5.6 respectively the capital and maintenance costs are calculated At

last, in Paragraph 5.7 the best port layout is concluded

1.4 Miscellaneous

To avoid misunderstandings while reading this report, one important remark is made:

• All compass directions are relative to the North, unless stated differently

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2 ENVIRONMENTAL BOUNDARY CONDITIONS

2.1 Introduction

In this chapter the collected field data is described and analysed thoroughly A large part of

the data has been obtained from a local survey, executed by the Vietnamese engineering

company TEDIPORT Normal and extreme conditions are considered, which enables the

determination of the serviceability of the port and the design of the port structures The

following boundary conditions are studied:

• Offshore wave climate

• Nearshore wave climate

The central coast of Vietnam is characterized by an abundance of small and medium size

estuaries and lagoons formed at the mouth of rivers that discharge the steep hinterland

More than 60 rivers meet the South China Sea along 1500 km of coastline Rivers usually

are short and steep with gradients generally steeper than 1:100 The coast is predominantly

sandy as a result of high fluvial sediment input during flood periods which nourish the

mainland beaches and sandy barriers that form across estuary mouths and tidal inlets

Mainland beaches and barriers are typically steep and narrow and are dominated by

cross-shore sediment transports The sediment of the beaches and barriers is rather coarse In

the south of the Central coast, the coast line is dominated by rocky headlands or by

sheltered bays behind headlands; sand deposition is limited to pocket beaches and river

mouths (TUNG, 2006)

2.3 Climate

In the central region a tropical monsoon climate is found In the plains and in the hills, the

average annual temperature is 25°C, but in the mountains 21°C From October to February

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Vietnam has a cool season with cold winds A high pressure system sets up over China and

drives winds across the ocean from the north-east This is called the winter monsoon, with

an average wind speed of 4 m/s and occasional strong winds up to 17 m/s The

temperatures can fall to 12°C in the plains but the average monthly temperature is still

20°C Relative humidity is high, between 85 and 95%

In the period May till August, when the continental high pressure area diminishes, the

summer monsoon sets in and causes winds from the SW Wind speeds are normally lower

than in the winter months, up to 11 m/s In this warmer period, average monthly

temperatures are 29°C in July, reaching up to 41°C occasionally The relative humidity is

lower, sometimes down to 50%

The annual rainfall ranges from 1500 mm to 4000 mm The rainy season is during the South

monsoon, from May to September; about 70 percent of the precipitation occurs in those

months The central region receives its maximum rainfall during tropical storms in

September to January.1

Thua Thien-Hue Province is made up of four different zones: the mountains, hills, plains and

lagoons which are separated from the sea by sand barriers

The mountains, covering more than half the total surface of the province, are along the

west and southwest border of the province, their height varying from 500 to 1480 meters

The hills are lower, between 20 to 200 meters and occupy a third of the area of the

province The plains account for about one tenth of the surface area, with a height of about

20 meters above sea level The lagoons occupy the remaining 5 percent of the surface area

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2.5 Bathymetry

With C-Map data2 a bathymetry has been created using QUICK-IN in DELFT3D (Figure 4) An

island, named Con Co, can be recognised together with some shoals further offshore The

contour lines show an inclined pattern, in which the continental shelf of North Vietnam can

be recognised

Port site

Water depth (m)

Shoals Con Co Island

100 km

Figure 4: bathymetry near Thua Thien-Hue Province obtained from C-map

In Figure 5 a close up bathymetry is shown, also obtained from C-Map The 20, 30 and 50 m

water depth isolines are clearly visible

25 km

20

30 50

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2.5.1 Cross-shore profile

In Figure 6 the cross-shore profile C-C' – as indicated in Figure 5 - is shown from -50 m up to

the dune at +5.0 m The first part is almost linear with a slope of 1:70 Further offshore, a

shallow area is found with a minimum water depth of -16.5 m Next, the profile continues

linearly towards deeper waters with a slope of 1:200 m

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2.6 Water levels

The sea level is frequently subject to fluctuations, mainly due to astronomical and

meteorological forces The tide causes water movement in a regular pattern and is the only

component that can be well predicted Meteorological influences - such as water level

setup due to low pressure, wind and waves – have an irregular character and cannot be

predicted Historical data about storms should provide an answer here Besides, sea level

rise has a long-term influence on the water level

In Paragraph 2.6.1 the tide is described and in Paragraph 2.6.2 the water level setup is

calculated In Paragraph 2.6.3 the sea level rise is discussed

2.6.1 Tide

The tidal regime at the future port location is mixed; i.e irregular semidiurnal, in which

semidiurnal constituents prevail This normally means two high (one Higher High Water and

one Lower High Water) and two low (one Higher Low Water and one Lower Low Water)

tides in a day See Figure 7

Figure 7: different water levels in a mixed tide

2.6.1.1 Data available

Data on the tide were collected from four sources:

• Local measurement at the port site

• Measurements (Hydro Meteorological Station at Cua Viet)

• British Admiralty Charts (UK Hydrographic Office)

• Global Inverse Tide Model (Oregon State University)

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The data sources where well analyzed and the local measurements proved to be the most

reliable data source In Paragraph 2.6.1.2 this data is described and conclusions are drawn

2.6.1.2 Local measurement

TEDIPORT – a Vietnamese engineering company – has conducted a water level survey from

09/12/2008 to 09/24/2008 In this period winds were calm, so it is assumed that the water

level registration is not influenced significantly by meteorological influences

Looking at the measurement in Figure 8 the tide reaches a maximum on 09/19/2008 of 41

cm, which is a spring tide – knowing that full moon was on the 09/15/2008 As well, at

09/19/2008 the lowest water level during the spring tide is measured, which is -48 cm

These water levels are measured with respect to National Datum (ND), which is equal to

the mean sea level

The maximum water level during spring tide – which is called Higher High Water Spring

(HHWS) - is considered as normative for design The minimum water level during spring tide

– which is called Lower Low Water Spring (LLWS) – is considered as Chart Datum (CD) The

HHWS becomes now 41 + 48 = 89 cm w.r.t CD Mean sea level (MSL) is 48 cm w.r.t CD

2.6.2 Water level setup

For the design of the port structures with a lifetime of 50 years, the maximum water level

has to be known in this period In statistical terms, this is a water level with a probability of

exceedance of once in 50 years As already stated in the introduction, the water level setup

consists of the following contributions:

Figure 8: measurement of the water level at the project site

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Pressure and wind effects are often combined during storms, generating very long waves

called storm surges, with a characteristic time-scale of several hours to one day and a

wavelength approximately equal to the width of the centre of the depression, typically

150–800 km (CIRIA, CUR, CETMEF, 2007)

For the Vietnamese coast the most severe storm surges are induced by typhoons For a

statistically correct calculation, this means that the once in 50 year typhoon conditions

have to be considered Here a simplification is made by taking the most severe typhoon

conditions which occurred in the last 50 years This was typhoon Harriet in 1970 with the

following characteristics:

• Wind speed (U10) = 52.4 m/s

• Atmosperic pressure P = 925 hPa

With this data the water level setup can be calculated

Atmospheric pressure

Low atmospheric pressure gives a water level rise, because surrounding waters are pushed

down by high pressure areas For open water domains, Equation 1 gives the relationship

between the rise in water level (in m) and the atmospheric pressure (in hPa) In the

formula, 1013 is the normal atmospheric pressure (= 1 atm = 1.013 bar = 1013 hPa) For a

value of 925 hPa, this gives a water level rise of 0.9 m

a

z =0.01 (1013∗ −p a)

Equation 1:water level rise due to low atmospheric pressure

Wind setup

The other contribution in storm surges is wind setup, see Figure 9 The wind induces a

gradient of the water surface, which can be calculated for a bottom profile with straight

and parallel bottom contours by Equation 2 The fetch is split up in 20 sections with

different water depths, as schematized in Figure 10 For the fetch length a distance of 250

km is taken, which is the average fetch in typhoons (see Appendix C) This results in a wind

setup of 3.3 m

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Figure 10: schematization of the fetch for wind-setup calculation.3

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Fetch nr Fetch length (m) Water depth (m) Set up (m)

Table 1: fetch schematization and wind setup calculation

Now the storm surge amounts:

2.6.2.2 Wave setup

Wave set-up is localized near to the shoreline, which is mainly caused by energy dissipation

due to depth-induced breaking of the incoming waves See Figure 11

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H0 = deep water wave height (m)

h = water depth (m)

ηmax = maximum wave setup (m)

Figure 11: schematization of wave setup

Figure 12: calculation of wave setup

CIRIA, CUR, CETMEF (2007) proposed a chart from which the wave setup at the shoreline

can be read for uniform sloping beaches To do so, the beach slope, the deep water wave

height H0 and the fictitious deep water wave steepness H0/L0 have to be known From the

wave model in Paragraph 2.9.2.1 it follows that H0 = 17.0 m with a return period of 50

years The steepness of this wave is 0.045 (-) The beach slope turns out to be 1:70 –

deduced from Figure 6 Now the wave setup becomes 1.7 m

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2.6.3 Sea level rise

In the Netherlands, the water level rise scenario due to climate change is 0.6 m in 100 years

for structures which are difficult to upgrade, like quay walls and terminals For a period of

50 years, 0.3 m has to be taken into account

2.6.4 Conclusion

2.6.4.1 Mean sea level

• MSL is 0.5 m w.r.t CD (rounded off)

2.6.4.2 Extreme water level

In Figure 13 the different water level contributions are schematically presented Summation

gives a 1/50 year water level of:

0.4 m 4.2 m

1.7 m 0.3 m

Figure 13: extreme water level contributions

This value is very large because all contributions are added up In practice, the event that all

the contributions occur at the same time has a low probability A probabilistic approach can

offer a more realistic solution in this situation, but will not be applied here Instead a factor

of 0.75 is introduced to obtain a more realistic result The approximated 1/50 year water

level becomes then: 0.75 * 7.1 = 5.3 m w.r.t CD

The once in 50 year water level is 5.3 m w.r.t CD

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2.7 Wind data

In Vietnam, monsoons winds are the governing force of the wind climate Extreme wind

conditions are induced by typhoons Several data sources have been collected, in which a

distinction is made between normal and extreme conditions The normal wind conditions

(Paragraph 2.7.2) are necessary to determine downtime as a consequence Extreme

conditions (Paragraph 2.7.3) have to be known in order to calculate extreme wave heights

2.7.1 Background

2.7.1.1 Monsoon winds

In Figure 14 the South-Asian monsoon system is shown, indicating the different origin of

the summer and winter monsoon In summer the wind is coming from the Southwest which

reverses in winter to Northeast

Figure 14: Asian summer and winter monsoon system

2.7.1.2 Typhoons

Since 1954, there have been 212 typhoons landing in or directly influencing Vietnam There

are about 30 typhoons originating in the Western Pacific Ocean each year of which about

10 are generated in the South China Sea On average, 4 to 6 hit or affect the Vietnam coast

each year

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Figure 15: typhoon Cecil, landed in Vietnam at the 15th of October, 1985

2.7.2 Normal conditions

Wind data were collected from several sources and are listed here:

• National Oceanic and Atmospheric Administration (NOAA, USA) - 12 year data

• China Sea Pilot (UKHO, 1978) – 130 year data

• Hydro Meteorological Station at Con Co Island (Vietnam) – 20 year data

The three data sources were well studied and the NOAA data source proved to be the most

applicable because omnidirectional data is provided Besides, there is also wave data

available from the NOAA which is favourable In Paragraph 2.7.2.2 the NOAA wind data is

described extensively As the data covers 'only' 12 years of measurement, the 130 year data

from the China Sea Pilot is used as a check The wind data from Con Co Island can be found

in Appendix B.1

2.7.2.1 China Sea Pilot

The China Sea Pilot describes wind measurements on ships which are carried out for over

130 years In the North western part of the South China Sea, monsoon winds are coming

from the NE in autumn and winter Typically, wind speeds do not exceed Beaufort 7 (14 - 17

m/s) In spring and summer, the dominant directions are SE and SW Winds speeds are

lower, not exceeding Beaufort 5 (8 - 11 m/s) The wind patterns in the different seasons of

the year are shown in Figure 16

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