Climate Change Driven Variations in Future
Longshore Sediment Transport Rates
along the Coast of Vietnam
Rev.4
March 2014
Authors :
Supott Thammasittirong (AIT)
Sutat Weesakul
(AIT)
Ali Dastgheib
Roshanka Ranasinghe
(UNESCO-IHE)
(UNESCO-IHE)
Executive Summary
Introduction
This report presents the results of the study on Climate Change driven variations in longshore
sediment transport rates along the coast of Vietnam. The project was funded by Ministry of
environment and infrastructure of the Netherlands.
Vietnam has been identified by the International Panel on Climate Change (IPCC, 2007, 2014)
as one of the countries that might be most affected by climate change. In particular the
Mekong and the Red River deltas, with their extremely high population density in low lying
areas, are severely threatened by sea level rise and anticipated increases in the frequency and
intensity of typhoons and storms. The coastline of Vietnam is presently severely eroded and
mangrove forests are reduced in area and density by severe storms and sea level rise. The
coastline of Vietnam is 3,260 kilometers long and consists of 114 river mouths, 48 Bays, 12
lagoons, and 3000 islands. Impacts of changing climate in the coastal zone are already
threatening people’s livelihoods as well as the ecological system.
Out of the many potential climate change (CC) impacts on coasts, the one impact that has
received most attention is coastline recession due to sea level rise (SLR), while little or no
attention has been given to other potential coastal CC impacts. Recent sutidies has highlighted
that other CC impacts may in fact override the SLR impact on coasts (Stive et al., 2009;
Ranasinghe and Stive, 2009; Ranasinghe et al., 2013). One such potentially severe CC impact
that has not been sufficiently investigated is the coastal response to CC driven variations in
offshore wave characteristics. Since longshore sediment transport is a direct function of
breaking wave height and direction, assessment of CC on the longshore sediment is now
possible for the Vietnamese coast due to a recent study of "Climate Change driven variations
in the wave climate along the coast of Vietnam" funded also by Ministry of environment and
infrastructure of the Netherlands. Changes in longshore sediment transport rates will
determine the coastline evolution in medium to long term time scales (i.e. 1 -100 years) and
spatial scales (i.e. 1 - 100 km).
Objective
The main objective of this study is to evaluate the impact of climate change on the large scale
longshore sediment transport rates along the coast of Vietnam.
Methodology
Wave characteristics are the most important input data for the calculation of longshore
sediment transport. The previous study on "Climate Change driven variations in the wave
climate along the coast of Vietnam" compared the present (1981 -2000) and the future (2081 2100) offshore wave climate at several locations along Vietnam coast using downscaled
output from two global climate models (ECHAM and GFDL).
i
In the present study, the 1981 -2000 and 2081 - 2100 offshore wave climate derived from the
aforementioned study are used to determine the nearshore wave climate for both time slices for
22 different coastline sections along the coast of Vietnam (Figure E-1). This was done by
using the spectral wave model SWAN model. The nearshore wave climate for the present time
slice (1981-2000) is used as the input to the GENESIS model to estimate annual average
longshore sediment transport at these 22 coastline sections. These model estimates were
verified with reported longshore sediment transport rates as far as possible. The verified
GENESIS model was then forced with the nearshore wave climate for 2081-2100 to estimate
future climate change modified longshore sediment transport along the Vietnam coast.
Figure E-1 Locations of 22 selected coastal sections along the Vietnam coastline.
ii
Results
The computed results indicate that the volume and direction of longshore sediment transport
along the coast of Vietnam is rather variable. For present conditions, the annual average
results from ECHAM and GFDL wave climate at 22 costal sections are found to be in the
range of 11,000-2,748,000 m3/year in total gross transport and 1,400-1,426,000 m3/year in net
transport in a northerly direction (at coastal section S2, S4 and S18-S21) and 35,000-2,740,000
m3/year in net transport in a southerly direction (at coastal section S1, S3, S5-S17 and S22).
For future conditions, the annual average results at the 22 costal sections are in the range of
10,000-3,403,000 m3/year in total gross transport and 2,000-1,569,000 m3/year in net transport
in a northerly direction (at coastal section S4, S9, S18-S21) and 500-3,174,000 m3/year in net
transport in a southerly direction (at coastal section S1-S3, S5-S8, S10-S17 and S22).
The estimated results of longshore sediment transport rates for the present (1981-2000) and
future (2081-2100) show significant changes in net longshore sediment transport rates along
the coast of Vietnam, with upto 0.5 million m3/year increase in the net transport rate at some
locations. Such large changes in longshore sediment transport rates can lead to significant
future variations in the position and orientation of the Vietnamese coastline.
The results are summarized in Table E-1. The magnitude of the change and its foreseen effect
on the coastline emphasizes the urgent need for detailed coastal morphological studies and
quantitative risk assessments at sensitive coastal areas along the coast of Vietnam. This
appears to be particularly the case in the vicinity of Danang (coastal sections 17, 18 and 19)
due to the large projected future changes in longshore sediment transport direction and
magnitude in this area, with an additional 875,000 m3 of sand being transported away from
this area per year.
iii
Table E.1 Changes in net sediment longshore sediment transport due to climate change
at 22 coastal sections along the Vietnam coastline.
Coastal section
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
S12
S13
S14
S15
S16
S17
S18
S19
S20
S21
S22
Description
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 62%, in the order of 30,000 m3/yr
There is no dominant direction of net longshore sediment transport in this section it will remain the
same upto 2100 but with more tendency toward the south. The magnitude will decrease with about 7%
in order of 1,000 m3/year in the southerly direction
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 34%, in the order of 125,000 m3/yr
There is no dominant direction of net longshore sediment transport in this section it will remain the
same upto 2100 but with more tendency toward the south. The magnitude will decrease with about
28% in order of 2,000 m3/year in the southerly direction
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 50%, in the order of 122,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 37%, in the order of 113,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 40%, in the order of 78,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 30%, in the order of 145,000 m3/yr
There is no dominant direction of net longshore sediment transport in this section it will remain the
same upto 2100 but with more tendency toward the north. The magnitude will increase with about
240% in order of 162,000 m3/year in the northerly direction
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 7%, in the order of 80,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 22%, in the order of 155,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 30%, in the order of 176,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 16%, in the order of 434,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 23%, in the order of 131,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 9%, in the order of 170,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 15%, in the order of 105,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 23%, in the order of 460,000 m3/yr
The net longshore sediment transport is toward the north at present and will remain towards the north
upto 2100. The magnitude of net annual transport increases by 45%, in the order of 290,000 m3/yr
The net longshore sediment transport is toward the north at present and will remain towards the north
upto 2100. The magnitude of net annual transport increases by 10%, in the order of 124,000 m3/yr
The net longshore sediment transport is toward the north at present and will remain towards the north
upto 2100. The magnitude of net annual transport increases by 15%, in the order of 170,000 m3/yr
The net longshore sediment transport is toward the north at present and will remain towards the north
upto 2100. The magnitude of net annual transport increases by 20%, in the order of 113,000 m3/yr
There is no dominant direction of net longshore sediment transport in this section it will remain the
same upto 2100 but with more tendency toward the north. The magnitude will increase by about 60% in
order of 5,000 m3/year in the northerly direction
iv
Table of Contents
Executive Summary ……………………...……………………………….
i
Table of Contents …………………………………………………………. v
List of Tables ………………………………………………………………. vi
List of Figures ………..…………………………………………………….
1
2
3
4
viii
Introduction ……………………………………………..…………………. 1
1.1
Background …………………………………………………………….
1.2
Statement of the Problems .…………………………………..…...…..... 1
1.3
Objectives of the Study ……………………………....…..……….……
1.4
Scope of the Study …………………………………………………..…. 2
1
2
Methodology ……………………………………………………..………… 3
2.1
Methods ……………..…………………………………………………. 3
2.2
GENESIS …………...…………..…………………………………..….
2.3
Computation of Longshore Sediment Transport for the Coast of ........... 6
Vietnam
5
Results and Discussion …………………………………………………… 15
3.1
Model Calibration ..…………………………………………………….
3.2
Modeling Results of Present Longshore Sediment Transport Rates …... 20
3.3
Modeling Results of Future Longshore Sediment Transport Rates ……
15
28
Conclusions ……………………………………...…………………….….... 40
v
List of Tables
Table
2.3-1
Page
Summary characteristics of the 22 coastal sections along the Vietnam
7
coastline
3.1-1
Comparison of computed and reported net longshore sediment
18
transport rates at coastal section S1, S19, S20 and S22
3.1-2
Comparison of computed and reported gross longshore sediment
18
transport rates at coastal section S1, S19, S20 and S22
3.2-1
Summary of computed net longshore sediment transport rates for
21
present ECHAM wave climate
3.2-2
Summary of computed gross longshore sediment transport rates for
22
present ECHAM wave climate
3.2-3
Summary of computed net longshore sediment transport rates for
23
present GFDL wave climate
3.2-4
Summary of computed gross longshore sediment transport rates for
24
present GFDL wave climate
3.2-5
Summary of average net and gross longshore sediment transport rate
25
calculated from GENESIS for present period along Vietnam coast
3.3-1
Summary of computed net longshore sediment transport rates for future
30
ECHAM wave climate
3.3-2
Summary of computed gross longshore sediment transport rates for future
31
ECHAM wave climate
3.3-3
Summary of computed net longshore sediment transport rates for future
32
GFDL wave climate
3.3-4
Summary of computed gross longshore sediment transport rates for future
33
GFDL wave climate
3.3-5
Summary of average net and gross longshore sediment transport rate
calculated from GENESIS for future period along the Vietnam coast
vi
34
Table (Cont’d)
3.3-6
Page
Future change in computed average net longshore sediment transport
34
rate from ECHAM and GFDL
3.3-7
Future change in computed average gross longshore sediment transport
35
rate from ECHAM and GFDL
4-1
Changes in net sediment longshore sediment transport at 22 coastal
sections along the Vietnam coastline due to climate change.
vii
41
List of Figures
Figure
Page
2.1-1
Locations at which future CC modified wave climate was obtained
4
2.3-1
Locations of 22 coastal sections along the Vietnam coastline for
8
GENESIS model simulation
2.3-2
Wave rose diagrams from ECHAM climate model for the present period
9
(1981-2000)
2.3-3
Wave rose diagrams from GFDL climate model for the present period
12
(1981-2000)
3.1-1
Locations of the previous research studies area
16
3.1-2
Comparison plots of net longshore sediment transport rates
19
3.1-3
Comparison plots of gross longshore sediment transport rates
19
3.2-1
Computed average net longshore sediment transport rates at
25
22 locations along Vietnam coast for present wave climate (1981-2000)
3.2-2
Computed average gross longshore sediment transport rates at
27
22 locations along Vietnam coast for present wave climate (1981-2000)
3.3-1
Estimates of present and future average net longshore sediment
35
transport rates at 22 costal sections
3.3-2
Estimates of present and future average gross longshore sediment
37
transport rates at 22 costal sections
3.3-3
Future change in average net longshore sediment transport rates at
38
the 22 costal sections along Vietnam Coast
3.3-4
Future change in average gross longshore sediment transport rates at
the 22 costal sections along Vietnam Coast
viii
39
CHAPTER 1
INTRODUCTION
1.1
Background
Vietnam has been identified by the International Panel on Climate Change (IPCC, 2007,
2014) as one of the countries to be most affected by climate change. In particular the
Mekong and the Red River deltas with their extremely high population density in low lying
areas are severely threatened by sea level rise and anticipated increases in the frequency
and intensity of typhoons and storms.
The coastline of Vietnam is 3,260 kilometres long and consists of 114 river mouths, 48
Bays, 12 lagoons, and 3000 islands. About 18 million people, almost a quarter of the total
population, live in the coastal districts of Vietnam. Impacts of changing climate in the
coastal zone are already threatening people’s livelihoods as well as the ecological system.
Coastlines are severely eroded and mangrove forests are reduced in area and density by
stronger storms and sea level rise. During the last 50 years, the sea level along Vietnam's
coastline has risen by approximately 20 cm, while the tropical cyclone frequency has
increased by 2.15 events per 50 years. Over the last 50 years, consistent coastal erosion has
been observed at 397 sites, covering a total coastline length of 1,000 km, at an average rate
of 5-10 m/yr, although at some locations long term erosion rates as large as 30-50 m/yr
have been reported. Most of the coastline in the south has been eroded continuously at a
rate of approximately 50 m/year since the early twentieth century (Cat et al., 2006, Mazda,
Y. et al., 2002). This massive erosion is mostly due to wave and current action and the
vanishing mangrove vegetation. Significant erosion also occurs in the central coastal zone
of Vietnam and preventive measures such as sea dykes, revetments, and tree plantations
have been implemented in many coastal areas.
Of the many potential climate change (CC) impacts on coasts, the one impact that has
received most attention is coastline recession due to sea level rise (SLR), while little or no
attention has been given to other potential coastal CC impacts. Recent literature has
highlighted that other CC impacts may in fact override the SLR impact on coasts (Stive et
al., 2009; Ranasinghe and Stive, 2009; Ranasinghe et al., 2013). One such potentially
severe CC impact that has not been sufficiently investigated is the coastal response to CC
driven variations in offshore wave characteristics. Assessment of this phenomenon is now
possible for the Vietnamese coast due to a recent study of "Climate Change driven
variations in the wave climate along the coast of Vietnam CCWaves Vietnam" funded via
the I&M-IHE MoU. Using state-of-the-art Global climate model output, dynamic
downscaling and wave modelling, CCWaves-Vietnam has provided future projections for
CC modified average wave conditions along the entire Vietnam coast.
1.2
Statement of the Problems
As longshore sediment transport is a direct function of breaking wave height and direction,
any future CC driven changes in these wave characteristics will have a profound impact on
longshore sediment transport rates, and therefore on coastlines, particularly at medium to
long term time scales (i.e. 1 -100 years) and medium to large spatial scales (i.e. 1 - 100
1
km). For example, persistent alongshore gradients in longshore sediment transport (even
small gradients) could result in chronic impacts such as coastline recession (Cowell et al.,
2003a, 2003b; Komar, 1998), inlet migration (FitzGerald, 1988), ebb/flood delta
depletion/accretion (Oertel, 1972) etc. Most, if not all, of these impacts are generally
considered as negative impacts by coastal managers/planners, and thus, over the last 50
years or so, there has been an enormous amount of research effort expended on developing
robust methods and tools to accurately predict longshore sediment transport rates for given
wave conditions.
The one-line longshore transport model (GENESIS) will be used in this study to calculate
the present and future longshore sediment transport rates along the entire coast of Vietnam
by using the offshore wave conditions determined in the previous CCWaves-Vietnam
study.
1.3
Objectives of the Study
The main objective of this study is to investigate the broad scale longshore sediment
transport rates for the coast of Vietnam and evaluate the effect of climate change on future
longshore sediment transport rates using projected average offshore wave conditions
determined in the previous CCWaves-Vietnam study.
1.4
Scope of the Study
In order to achieve the objectives, the scope of study can be defined as follows:
1) The present (1981-2000) and future (2081-2100) of ECHAM and GFDL wave
climate determined in the previous CCWaves-Vietnam study will be used as
wave input data in the GENESIS model.
2) The longshore sediment transport rates will be calculated by the GENESIS
model at the 22 selected coastal locations along the Vietnam coastline.
2
CHAPTER 2
METHODOLOGY
2.1
Methods
Wave characteristics are the most important input data for the calculation of longshore
sediment transport. The CCWaves-Vietnam study derived the future (2081 -2100) CC
modified wave climate at 10 more or less equally spaced locations along Vietnam coast
(Figure 2.1-1). To achieve this, CCWaves-Vietnam adopted the spectral wave model,
MIKE21 SW, which was forced with climate model (ECHAM and GFDL) derived winds
for the A2 greenhouse gas (GHG) scenario, dynamically downscaled using CSIRO’s
(Australia) CCAM stretched grid model for three time slices; 1981 -2000, 2041-2060 and
2081 - 2100. The A2 scenario is a high end GHG scenario and thus represents a worst case
situation. The output consisted of 6 hourly significant wave height, wave period and wave
direction for the present (1981 to 2000) and the future (2041 to 2060 and 2060 to 2100).
In this study we will first use the above described 1981 -2000 wave conditions to calculate
contemporary longshore sediment transport rates using a process based longshore transport
model (GENESIS model) at the nearshore coastal locations corresponding to the above
mention 10 offshore wave locations, and verify model results with reported longshore
sediment transport rates at these locations (i.e. model validation). Subsequently, projected
wave conditions for the 2081-2100 time slice will be used in the validated model to derive
estimates of future CC modified longshore sediment transport rates at the selected coastal
locations along the Vietnam coastline.
The main steps of the methodological procedure that will be adopted are summarized
below:
Step 1: Offshore wave characteristics (~ 50km offshore) will be obtained from the
previous CCWaves-Vietnam study for the present (1981 -2000) and future (2081 - 2100)
time slices at 10 more or less equally spaced locations along the coast of Vietnam (see
Figure 2.1-1).
Step 2: The SWAN model, which is based on the deep water third generation wave
model (WAM model), will be used to transform the offshore wave data to the nearshore
wave data which can be used in GENESIS.
Step 3: The wave characteristics for the present time slice will be used in GENESIS to
obtain annual average longshore sediment transport estimates at 22 selected nearshore
locations. These model estimates will then be verified with reported longshore sediment
transport rates at or near the selected locations as far as possible. The model will be
iteratively calibrated until the best possible match between modelled and reported
longshore sediment transport rates is achieved. This will result in a validated GENESIS
Model which can then be used confidently to obtain forecasts.
3
Step 4: The validated GENESIS model will be forced with nearshore wave characteristics
for the future time slice to obtain the rates of potential sediment transport for 2081-2100.
Step 5: Longshore sediment transport rates predicted for the two time slices will be
subjected to a sophisticated statistical analysis to determine areas along the Vietnam coast
where CC may result in significant changes in longshore sediment transport rates and
subsequent changes in the coastline
Figure 2.1-1 Locations at which future CC modified wave climate was obtained
4
2.2
GENESIS
GENESIS, developed by Coastal Engineering Research Center (CERC), US Army Corps
of Engineers, is designed to simulate long-term shoreline change on an open coast, as
produced by spatial and temporal differences in longshore sand transport (Hanson 1987,
1989; Hanson and Kraus 1989). The name GENESIS is an acronym that stands for
GENEralized model for Simulating Shoreline Change. The modeling system is founded on
considerable research and applications of shoreline change numerical models. Wave action
is the mechanism producing the longshore sand transport, and, in GENESIS, spatial and
temporal differences in the transport rate may be caused by such diverse factors as irregular
bottom bathymetry, wave diffraction, boundary conditions, line sources and sinks of sand.
There are also constraints on transport (such as seawalls and groins). These factors are
interrelated and may work in different combinations at different times.
The GENESIS model is generalized in that it allows simulation of a wide variety of userspecified offshore wave inputs, initial beach plan shape configurations, coastal structures,
and beach fills. Input to the model is the shoreline position, beach profiles and a time series
of significant wave height, significant wave period, and the direction. Based on these data,
the model calculates wave breaking properties, longshore sediment transport rates, and
shoreline positions.
The empirical predictive formula for the long-shore sand transport rate used in this model
is:
𝜕𝐻
𝑄 = (𝐻 2 𝐶𝑔 ) [𝑎1 sin 𝜃𝑏𝑠 − 𝑎2 cos 𝜃𝑏𝑠 𝜕𝑥 ]
𝑏
(2.1)
𝑏
where 𝐻 is the wave height (m), 𝐶𝑔 is the wave group speed given by linear wave theory, b
subscript denoting wave breaking condition and 𝜃𝑏𝑠 is the angle of breaking waves to the
local shoreline and the non-dimensional parameters 𝑎1 and 𝑎2 are given by:
𝑎1 =
and
𝑎2 =
𝑘1
5
𝜌
16 ( 𝑠⁄𝜌 − 1)(1 − 𝑝) (1.416 ⁄2 )
(2.2)
𝑘2
7
𝜌𝑠
8 ( ⁄𝜌 − 1)(1 − 𝑝) tan 𝛽 (1.416 ⁄2 )
where 𝑘1 and 𝑘2 are the empirical coefficient which treated as the calibration parameters,
𝜌𝑠 is the density of sand (taken to be 2.65x103 kg/m3 for quartz sand), 𝜌 is the density of
water (1.03x103 kg/m3 for sea water), 𝑝 is the porosity of sand on the bed (taken to be 0.4)
and tan 𝛽 is the average bottom slope from the shoreline to the depth of active longshore
sand transport.
5
2.3
Computation of Longshore Sediment Transport for the Coast of Vietnam
The GENESIS model is applied to compute the longshore sediment transport rates for the
coast of Vietnam. The study area covers 22 selected sandy coastal sections starting from
the south to the north of Vietnam’s coast (S1 to S22) as shown in Figure 2.3-1. This model
is a one-dimensional model grid system where to the north, south and east of the study
domain is the sea, while to the west is the land.
In order to employ GENESIS for sediment transport computations, the initial data of
coastline position, offshore/nearshore wave and other parameters must be obtained.
-
Coastline Position
The actual coastline shape (position) of each of the 22 coastal sections considered is
simplified to a straight coastline (with coastline orientation obtained from Google Earth)
with the assumption that there are no changes in coastline position or effects of structures
such as groins, offshore breakwaters and revetments within each section.
-
Wave Data
Offshore wave data obtained from the previous CCWaves-Vietnam study at 10
more or less equally spaced locations along the coast of Vietnam (see Figure 2.1-1), were
transformed through wave propagation modelling (SWAN model). The nearshore positions
are located outside the region of breaking waves such that the wave parameters extracted
can be applied to calculate longshore sediment transport. The significant wave height,
significant wave period and wave direction from two climate models (GFDL and ECHAM)
for the present (1981-2000) and future (2081-2100) time slices at the nearest grid points to
the 22 coastal sections of the study area provided by SWAN model, were be used as input
data for GENESIS model. The wave rose diagrams of the significant wave height at each
coastline sections for present period during 1981-2000 are shown in Figure 2.3-2 and 2.3-3,
while the results for the future period during 2081-2100 are shown in Appendix A.
The wave rose diagrams show that along the coast of Vietnam the wave direction is
very dominantly from northeast to east corresponding to the northeast monsoon. The wave
height and frequency of waves due to the northeast monsoon are also the strongest.
-
Other input parameters
Other input parameters such as mean sediment grin size d50, beach profiles, berm
height and depth of closure were obtained from available projects.
The summary characteristics of the 22 coastal sections (S1 to S22) are presented in Table
2.3-1.
6
Table 2.3-1 Summary characteristics of the 22 coastal sections along the Vietnam
coastline.
Section
No.
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
S12
S13
S14
S15
S16
S17
S18
S19
S20
S21
S22
Length of coastal
section
(km)
83.5
16.1
26.2
10.6
76.4
25.4
19.1
34.6
9.2
11.7
10.3
11.3
6.2
15.6
9.4
46.5
6.5
117.6
139.5
111.8
120.0
114.0
Coastline orientation
(degree)
151.8
184.2
116.7
184.7
144.7
97.9
118.3
55.5
53.9
62.0
64.4
58.6
91.9
65.9
82.3
65.0
110.4
48.3
37.6
46.1
48.1
97.7
7
Water depth at input
waves
(m)
26
29
29
29
27
29
26
38
47
39
27
22
22
20
20
27
21
29
25
26
28
25
Mean sediment
grin size d50
(mm)
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
Figure 2.3-1 Locations of 22 coastal sections along the Vietnam coastline for
GENESIS model simulation
8
N
N
Calm
68.61 %
Calm
65.48 %
Palette
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S2
Coastal Section S1
N
N
Calm
61.33 %
Calm
61.33 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S4
Coastal Section S3
N
N
Calm
56.79 %
Calm
64.15 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Coastal Section S5
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S6
N
N
Calm
72.19 %
Calm
53.18 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
5%
Coastal Section S7
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S8
Figure 2.3-2 Wave rose diagrams from ECHAM climate model for the present period
(1981-2000)
9
N
N
Calm
51.15 %
Calm
50.90 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Coastal Section S9
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S10
N
N
Calm
50.60 %
Calm
51.84 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S12
Coastal Section S11
N
N
Calm
50.72 %
Calm
51.84 %
Palette
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S13
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S14
Figure 2.3-2 (cont’d) Wave rose diagrams from ECHAM climate model for the
present period (1981-2000)
10
N
N
Calm
50.72 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Calm
50.33 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S16
Coastal Section S15
N
N
Palette
Calm
50.37 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
Calm
51.44 %
5%
Coastal Section S17
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S18
N
N
Palette
Calm
51.52 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
Calm
51.59 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S20
Coastal Section S19
N
N
Calm
64.81 %
Calm
56.17 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S22
Coastal Section S21
Figure 2.3-2 (cont’d) Wave rose diagrams from ECHAM climate model for the
present period (1981-2000)
11
N
N
Calm
68.34 %
Calm
71.72 %
Palette
Palette
Coastal Section S1
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
N
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S2
N
Calm
63.14 %
Calm
63.14 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S4
Coastal Section S3
N
N
Calm
57.78 %
Calm
67.57 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S5
5%
N
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S6
N
Calm
77.02 %
Calm
53.46 %
Palette
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S8
Coastal Section S7
Figure 2.3-3 Wave rose diagrams from GFDL climate model for the present period
(1981-2000)
12
N
N
Calm
50.77 %
Calm
50.70 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Coastal Section S9
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S10
N
N
Calm
50.48 %
Calm
51.89 %
Palette
5%
N
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S12
Coastal Section S11
N
Calm
51.89 %
Calm
50.89 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S14
Coastal Section S13
Figure 2.3-3 (cont’d) Wave rose diagrams from GFDL climate model for the present
period (1981-2000)
13
N
N
Calm
50.89 %
Calm
50.37 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
5%
Coastal Section S15
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S16
N
N
Calm
50.40 %
Calm
51.57 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Coastal Section S17
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S18
N
N
Palette
Palette
Calm
51.64 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Calm
52.08 %
5%
Coastal Section S19
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S20
N
N
Calm
58.73 %
Calm
69.67 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
5%
Coastal Section S21
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S22
Figure 2.3-3 (cont’d) Wave rose diagrams from GFDL climate model for the present
period (1981-2000)
14
CHAPTER 3
RESULTS AND DISCUSSION
3.1
Model Calibration
The computed longshore sediment transport rates from this study will be compared with
longshore sediment transport rates reported in literature at or near the selected locations for
the present time slice (1980-2000).
There are various research studies of longshore sediment transport for the coast of
Vietnam, but most of them are focused on the central coast of Vietnam, especially at the
coast of Thua Thien-Hue province. Estimations of longshore sediment transport rates at
some areas along the coast of Vietnam from previous research studies are selected for
model calibration and comparison as shown in Figure 3.1-1. The results of these previous
research studies can be summarized as follows:
(1) Northern coast of Vietnam at Hai Hau Beach (Nam Dinh province)
Hung et al. (2006) computes the longshore sediment transport at Hai Hau beach
using the program SEDTRAN with input wave conditions during 2001-2005. The
estimated net sediment transport is 63,000 m3/year in a southwest direction (which agrees
with the enlargement of the sand spit toward the southwest and the southwest overlapping
of the bypass bar in the Ninh Co mouth), while the gross transport is 490,000 m3/year. In
the present study, the GENESIS model was used for shoreline change simulation at Hai
Hau beach with calibration parameters 𝑘1 = 0.80 and 𝑘2 = 0.40. The best fit between
calculated and measured coastline positions for the period from 1912 to 1965 and 2001 to
2005 was determined for model calibration and verification, respectively.
(2)
province
Central coast of Vietnam at Thua Thien Hue province and Quang Binh
Tran Quang Tien (2004) calculates the longshore sediment transport in littoral zone
of Vietnam Central using the Bijker method, CERC method and the improved method
based on the Meyer-Peter formula with 2002 hindcasted waves. The computed results at
Thuan An area (Thua Thien Hue province) was found to be in the range of 600,0001,100,000 m3/year in total gross transport and 400,000-700,000 m3/year in net transport in
a northwest direction while the net transport at Hai Duong (Thua Thien Hue province) and
Ngu Thuy (Quang Binh province) is about 1,500,000 m3/year and 900,000 m3/year in a
northwest direction, respectively. In the present study, the GENESIS model was used for
shoreline change simulation at Thuan An beach with calibration parameters 𝑘1 = 0.75 and
𝑘2 = 0.50. The result of GENESIS agreed well with recent observed trend along this
shoreline.
15
Hai Hau Beach
Ngu Thuy
Hai Duong
Thuan An Beach
Tat Channel
LEGEND
Coastal sections of this study area
Previous research study area
Figure 3.1-1 Locations of the previous research studies area
16
Lam (2009) evaluates different measurements and calculations of the longshore
sediment transport for the coast of Thua Thien Hue done by different authors through the
years 1970-2004. The most reasonable results (with an agreement with the development of
the sand spit and dredge records) is found to be in the range of 600,000-1,600,000 m3/year
in total gross transport and 300,000-700,000 m3/year in net transport in a northwest
direction.
(3) Southern coast of Vietnam at Tat channel, near Mekong delta
Q.T.Doan et al. (2013) presents the calculation results of littoral sediment transport
at Tat channel (Phu Long province) using the LITDRIFT model with input wave condition
during 9 years from 1999 to 2008. The estimated net sediment transport was found to be in
the range of 150,000-170,000 m3/year in a southwest direction.
The sediment transports in the present time slice (1980-2000) at or near the above selected
locations, which are coastal section S1, S19, S20 and S22, were computed by the
GENESIS model. First, the calibration parameters 𝑘1 and 𝑘2 were set equal to the values of
previous studies and has finally been adjusted after comparing the computed results of net
and gross longshore sediment transport rates between this study and the previous studies.
The selected values of the calibration parameters 𝑘1 and 𝑘2 are shown in the following
table:
Coastal Section
S1
S19
S20
S22
𝑘1
0.95
0.65
0.75
0.80
𝑘2
0.50
0.50
0.50
0.40
The computed results of net and gross longshore sediment transport rates from the
GENESIS model at these coastal sections and corresponding reliable estimated values
reported in literature are summarized in Table 3.1-1 and Table 3.1-2. The comparison plots
of longshore sediment transport rates between the computed results and the reported values
are shown in Figure 3.1-2 and 3.1-3.
The computed results of longshore sediment transport rates seem to vary annually and
depend on the wave climate condition (ECHAM or GFDL) and coastline orientation as
well. However, there is reasonable quantitative agreement between the computed results
and the reported values. Difference in methods and period of computation, coastline
orientation and wave climate condition are the main reasons that cause the difference of
longshore sediment transport rates between this study and previous studies. For example, at
Thuan An beach (located in coastal section S19), the previous study of Tran Quang Tien in
2004 were used hindcast wave in 2002 as input data for the calculation of longshore
sediment transport by CERC, Bijker, and Meyer-Peter improved method. While in this
17
study, the 1981-2000 of ECHAM and GFDL wave climate data were used as input data in
GENESIS model to compute longshore sediment transport rate.
Thus, the above 𝑘1 and 𝑘2 values were used as calibration coefficients in GENESIS with
input ECHAM and GFDL wave climate to calculate annual longshore sediment transport at
other coastal sections for the present (1981 -2000) and future (2081 - 2100) time slices.
Table 3.1-1 Comparison of computed and reported net longshore sediment transport
rates at coastal section S1, S19, S20 and S22.
Study Area
Coastal
section
Nearby area
S1
Estimates of Qnet (m3/yr)*
This study
ECHAM wave
33,000 to 102,000
-786,000 to -1,772,000
Tat channel
Thuan An
S19
beach
-786,000 to -1,772,000
S19
Hai Duong
-768,000 to -1,725,000
S20
Nqu Thuy
-21,000 to 71,000
S22
Hai Hau beach
Note: (*) the positive transport direction is southward
Previous study
GFDL wave
9,000 to 77,000
-721,000 to -1,703,000
150,000 to 170,000
-300,000 to -700,000
-721,000 to -1,703,000
-684,000 to -1,579,000
5,000 to 111,000
-1,500,000
-900,000
63,000
Table 3.1-2 Comparison of computed and reported gross longshore sediment
transport rates at coastal section S1, S19, S20 and S22.
Study Area
Coastal
Section
S1
S19
S19
S20
S22
Nearby area
Tat channel
Thuan An
beach
Hai Duong
Nqu Thuy
Hai Hau beach
Estimates of Qgross (m3/yr)
This study
Previous study
ECHAM wave
96,380 to 168,000
GFDL wave
73,892 to 151,000
787,000 to 1,772,000
721,000 to 1,705,000
600,000 to 1,600,000
787,000 to 1,772,000
769,000 to 1,727,000
77,000 to 136,000
721,000 to 1,705,000
686,000 to 1,580,000
53,000 to 152,000
N/A
N/A
490,000
18
N/A
Figure 3.1-2 Comparison plots of net longshore sediment transport rates
Figure 3.1-3 Comparison plots of gross longshore sediment transport rates
19
3.2
Modeling Results of Present Longshore Sediment Transport Rates
Modeling work of GENESIS was conducted at 22 coastal sections along the coast of
Vietnam as shown in Figure 3.1-1. The computed annual net and gross longshore sediment
transport rates for the present time slice (1981-2000) at the 22 locations are summarized in
Table 3.2-1 to 3.2-4, while the average annual net and gross longshore sediment transport
rates are summarized in Table 3.2-5 and shown in Figure 3.2-1 to 3.2-2. The plots of
computed average annual net and gross longshore sediment transport rates at 22 locations
are shown in Appendix B.
The computed results indicate that the magnitude and direction of longshore sediment
transport along the coast of Vietnam is rather variable. The annual average results at 22
costal sections from ECHAM wave climate input data are found to be in the range of
12,000-2,780,000 m3/year in total gross transport and 900-1,457,000 m3/year in net
transport in a northerly direction (at coastal section S2, S4, S9 and S18-S21) and 26,0002,750,000 m3/year in net transport in a southerly direction (at coastal section S1, S3, S5-S8,
S10-S17 and S22). While, the results from GFDL wave climate input data are found to be
in the range of 11,000-2,748,000 m3/year in total gross transport and 1,900-1,390,000
m3/year in net transport in a northerly direction (at coastal section S2, S4, S18- S21) and
32,000-2,720,000 m3/year in net transport in a southerly direction (at coastal section S1,
S3, S5-S17 and S22).
Comparison of average computed results of annual longshore sediment transport rates from
ECHAM and GFDL at each coastal section for 1981-2000 in Figure 3.2-1 and 3.2-2 show
that all of them have similar magnitude and direction, except at S9.
There are significant temporal variations in the computed annual longshore sediment
transport rates from both ECHAM and GFDL wave climates during 1981-2000 as shown
in Appendix B. The results from ECHAM wave climate seem to have less fluctuation than
the results from GFDL wave climate except during the period 1994-1997.
20
Table 3.2-1 Summary of computed net longshore sediment transport rates for
present ECHAM wave climate.
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Average
Section1
78,000
40,128
54,270
38,000
102,000
86,000
74,000
64,000
33,000
45,000
69,000
63,000
47,000
93,000
87,000
58,000
66,000
43,000
77,000
75,000
64,620
Section2
-753
-3,205
620
6,301
-3,558
-346
1,860
381
-1,545
-736
260
-513
-6,843
4,358
1,094
-7,602
-674
-1,680
-1,215
-3,539
-867
Net Longshore Sediment Transport Rates for Present ECHAM Wave Climate (m 3/year)
Section3
Section4
Section5
Section6
Section7
Section8
Section9 Section10 Section11
474,000
-5,263
314,000
385,000
253,000
367,000
-7,000
977,000
585,000
267,000
-7,348
178,000
216,000
150,000
248,000
31,000
625,000
394,000
349,000
-1,790
240,000
287,000
190,000
400,000
40,000
926,000
569,000
393,000
5,671
267,000
323,000
196,000
417,000
37,000 1,019,000
604,000
568,000
-6,793
377,000
462,000
308,000
342,000
-87,000
997,000
568,000
509,000
-3,268
408,000
430,000
287,000
410,000
33,000 1,195,000
703,000
442,000
189
300,000
366,000
241,000
271,000
-176,000
841,000
447,000
422,000
-2,145
286,000
349,000
229,000
289,000
-139,000
839,000
450,000
358,000
-5,013
206,000
295,000
191,000
231,000
-152,000
648,000
343,000
321,000
-4,601
191,000
259,000
175,000
189,000
-155,000
523,000
265,000
395,000
-3,632
321,000
330,000
223,000
392,000
44,000 1,022,000
619,000
468,000
-4,443
310,000
386,000
248,000
581,000
88,000 1,292,000
790,000
360,000
-11,967
237,000
299,000
202,000
290,000
-74,000
775,000
434,000
295,000
865
215,000
214,000
158,000
329,000
105,000
797,000
512,000
542,000
-1,276
413,000
457,000
290,000
539,000
100,000 1,397,000
885,000
567,000
-12,599
392,000
471,000
292,000
835,000
524,000 1,834,000 1,294,000
400,000
-5,673
234,000
316,000
211,000
310,000
-87,000
819,000
479,000
361,000
-5,607
245,000
298,000
192,000
368,000
41,000
924,000
557,000
451,000
-3,688
297,000
368,000
243,000
273,000
-125,000
807,000
440,000
481,000
-6,662
313,000
391,000
261,000
202,000
-191,000
706,000
358,000
421,150
-4,252
287,200
345,100
227,000
364,150
-7,500
948,150
564,800
Note: the positive transport direction is southward
Table 3.2-1 (cont’d) Summary of computed net longshore sediment transport rates
for present ECHAM wave climate.
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Average
Net Longshore Sediment Transport Rates for Present ECHAM Wave Climate (m 3/year)
Section12 Section13 Section14 Section15 Section16 Section17 Section18 Section19 Section20 Section21 Section22
436,000 2,767,000
484,000 1,799,000
620,000 2,176,000
-861,000 -1,156,000 -1,135,000
-624,000
16,590
297,000 1,738,000
312,000 1,123,000
392,000 1,339,000
-537,000
-786,000
-768,000 -438,000
16,093
441,000 2,537,000
464,000 1,651,000
590,000 1,970,000
-830,000 -1,300,000 -1,262,000
-678,000
36,275
477,000 2,874,000
467,000 1,818,000
618,000 2,208,000
-906,000 -1,288,000 -1,267,000
-727,000
41,000
430,000 3,013,000
488,000 1,945,000
642,000 2,420,000 -1,007,000 -1,392,000 -1,366,000
-730,000
15,585
530,000 3,406,000
534,000 2,139,000
713,000 2,615,000 -1,000,000 -1,343,000 -1,307,000
-690,000
21,385
305,000 2,730,000
392,000 1,742,000
536,000 2,237,000
-988,000 -1,291,000 -1,271,000
-696,000
15,890
314,000 2,673,000
378,000 1,692,000
520,000 2,165,000
-951,000 -1,256,000 -1,242,000
-682,000
14,051
241,000 2,146,000
307,000 1,374,000
416,000 1,772,000
-807,000 -1,099,000 -1,086,000
-611,000
20,078
179,000 1,804,000
239,000 1,146,000
325,000 1,496,000
-706,000
-934,000
-938,000 -520,000
-21,250
466,000 3,011,000
448,000 1,854,000
613,000 2,288,000
-875,000 -1,294,000 -1,252,000
-674,000
41,000
628,000 3,513,000
639,000 2,283,000
818,000 2,716,000 -1,122,000 -1,772,000 -1,725,000
-931,000
58,000
313,000 2,490,000
331,000 1,536,000
459,000 1,968,000
-842,000 -1,179,000 -1,158,000
-612,000
8,851
400,000 2,056,000
398,000 1,335,000
496,000 1,544,000
-619,000
-987,000
-951,000 -529,000
45,505
666,000 3,867,000
684,000 2,469,000
889,000 2,934,000 -1,127,000 -1,682,000 -1,623,000
-841,000
58,000
1,054,000 4,292,000
973,000 2,826,000 1,177,000 3,043,000
-974,000 -1,621,000 -1,544,000
-777,000
71,000
336,000 2,644,000
375,000 1,656,000
507,000 2,097,000
-935,000 -1,295,000 -1,284,000
-710,000
24,259
424,000 2,579,000
433,000 1,641,000
563,000 1,984,000
-830,000 -1,236,000 -1,202,000
-653,000
49,234
311,000 2,559,000
376,000 1,630,000
504,000 2,071,000
-900,000 -1,251,000 -1,253,000
-666,000
7,867
244,000 2,383,000
321,000 1,514,000
437,000 1,969,000
-864,000 -1,088,000 -1,105,000
-600,000
-11,974
424,600 2,754,100
452,150 1,758,650
591,750 2,150,600
-884,050 -1,262,500 -1,236,950
-669,450
26,372
Note: the positive transport direction is southward
21
Table 3.2-2 Summary of computed gross longshore sediment transport rates for
present ECHAM wave climate.
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Average
Section1
139,000
96,380
98,549
138,000
148,000
146,000
128,000
112,000
115,000
100,000
125,000
134,000
105,000
116,000
134,000
168,000
131,000
116,000
108,000
129,000
124,346
Section2
11,539
11,176
10,026
21,982
8,331
15,382
10,863
9,377
10,309
13,064
11,589
11,521
10,200
12,420
10,228
12,512
13,488
16,484
7,068
11,907
11,973
Gross Longshore Sediment Transport Rates for Present ECHAM Wave Climate (m 3/year)
Section3
Section4
Section5
Section6
Section7
Section8
Section9
493,000
13,162
364,000
389,000
263,000
524,000
531,000
281,000
14,408
226,000
222,000
160,000
367,000
354,000
365,000
12,361
273,000
292,000
200,000
545,000
518,000
452,000
28,597
362,000
367,000
254,000
594,000
649,000
582,000
11,571
420,000
467,000
319,000
593,000
755,000
524,000
19,644
449,000
434,000
295,000
574,000
587,000
467,000
13,724
343,000
375,000
257,000
414,000
482,000
440,000
11,144
323,000
356,000
241,000
409,000
476,000
389,000
13,374
272,000
306,000
214,000
401,000
490,000
335,000
16,165
233,000
265,000
185,000
334,000
480,000
413,000
13,527
367,000
336,000
236,000
542,000
545,000
490,000
13,201
368,000
393,000
263,000
702,000
829,000
372,000
14,243
294,000
301,000
212,000
476,000
538,000
305,000
13,604
237,000
227,000
166,000
500,000
403,000
562,000
12,496
454,000
466,000
305,000
617,000
563,000
594,000
16,862
473,000
475,000
309,000
939,000
936,000
419,000
15,795
290,000
322,000
225,000
506,000
580,000
390,000
22,259
311,000
314,000
215,000
483,000
454,000
459,000
8,564
320,000
371,000
249,000
431,000
532,000
494,000
16,073
353,000
394,000
267,000
417,000
494,000
441,300
15,039
336,600
353,600
241,750
518,400
559,800
Section10 Section11
1,107,000
767,000
757,000
538,000
1,046,000
752,000
1,216,000
885,000
1,116,000
821,000
1,308,000
856,000
924,000
608,000
937,000
611,000
764,000
546,000
638,000
478,000
1,143,000
784,000
1,371,000
975,000
923,000
667,000
941,000
678,000
1,441,000
956,000
1,871,000 1,357,000
929,000
672,000
1,038,000
711,000
881,000
580,000
829,000
569,000
1,059,000
740,550
Table 3.2-2 (cont’d) Summary of computed gross longshore sediment transport rates
for present ECHAM wave climate.
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Average
Section12
629,000
440,000
630,000
731,000
697,000
689,000
493,000
495,000
461,000
408,000
637,000
839,000
555,000
557,000
751,000
1,143,000
558,000
582,000
477,000
463,000
611,750
Gross Longshore Sediment Transport Rates for Present ECHAM Wave Climate (m 3/year)
Section13 Section14 Section15 Section16 Section17 Section18 Section19 Section20 Section21 Section22
2,786,000
621,000 1,835,000
743,000 2,192,000
863,000 1,157,000 1,135,000
624,000
92,396
1,771,000
431,000 1,187,000
513,000 1,366,000
551,000
787,000
769,000
438,000
77,638
2,551,000
600,000 1,678,000
705,000 1,984,000
847,000 1,301,000 1,263,000
678,000
92,439
2,925,000
711,000 1,951,000
827,000 2,267,000
914,000 1,288,000 1,268,000
727,000
105,000
3,025,000
663,000 1,967,000
769,000 2,435,000 1,039,000 1,393,000 1,368,000
730,000
91,949
3,438,000
658,000 2,197,000
824,000 2,645,000 1,005,000 1,344,000 1,308,000
690,000
91,647
2,743,000
504,000 1,765,000
617,000 2,251,000
989,000 1,291,000 1,271,000
696,000
84,172
2,690,000
498,000 1,722,000
612,000 2,181,000
959,000 1,256,000 1,242,000
682,000
79,602
2,160,000
454,000 1,409,000
524,000 1,787,000
830,000 1,100,000 1,087,000
611,000
85,469
1,842,000
394,000 1,205,000
453,000 1,545,000
712,000
935,000
938,000
520,000
80,090
3,043,000
589,000 1,915,000
739,000 2,317,000
889,000 1,295,000 1,253,000
674,000
106,000
3,526,000
768,000 2,304,000
908,000 2,729,000 1,205,000 1,772,000 1,727,000
931,000
136,000
2,510,000
521,000 1,576,000
612,000 1,987,000
848,000 1,179,000 1,159,000
612,000
87,319
2,094,000
536,000 1,406,000
635,000 1,579,000
626,000
988,000
952,000
529,000
99,518
3,876,000
729,000 2,482,000
927,000 2,946,000 1,131,000 1,682,000 1,624,000
841,000
107,000
4,307,000 1,022,000 2,848,000 1,214,000 3,062,000 1,001,000 1,621,000 1,544,000
777,000
115,000
2,667,000
513,000 1,694,000
616,000 2,120,000
938,000 1,296,000 1,286,000
710,000
96,889
2,608,000
562,000 1,702,000
675,000 2,005,000
837,000 1,236,000 1,202,000
653,000
96,106
2,568,000
474,000 1,644,000
576,000 2,080,000
951,000 1,253,000 1,253,000
666,000
78,677
2,399,000
472,000 1,548,000
554,000 1,982,000
877,000 1,089,000 1,106,000
600,000
79,444
2,776,450
586,000 1,801,750
702,150 2,173,000
900,600 1,263,150 1,237,750
669,450
94,118
22
Table 3.2-3 Summary of computed net longshore sediment transport rates for
present GFDL wave climate.
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Average
Section1
28,000
46,000
35,000
66,007
43,000
13,000
14,000
71,941
9,000
60,000
43,845
74,497
11,000
17,528
32,000
20,000
42,000
77,000
41,125
69,210
40,708
Section2
-1,850
-2,536
-8,334
4,275
-4,741
-5,995
-3,435
7,556
-3,924
-4,953
5,160
922
-6,404
217
-3,809
-4,293
-1,375
-4,105
-7,037
6,336
-1,916
Net Longshore Sediment Transport Rates for Present GFDL Wave Climate (m 3/year)
Section3
Section4
Section5
Section6
Section7
Section8
Section9 Section10 Section11
310,000
-5,578
185,000
260,000
157,000
427,000
157,000
913,000
603,000
475,000
-7,692
400,000
416,000
259,000
975,000
756,000 1,978,000 1,452,000
414,000
-13,912
248,000
337,000
201,000
867,000
612,000 1,695,000 1,238,000
308,000
2,622
273,000
254,000
172,000
622,000
392,000 1,325,000
910,000
462,000
-7,581
327,000
385,000
233,000
971,000
680,000 1,950,000 1,418,000
300,000
-10,879
151,000
244,000
155,000
218,000
-14,000
580,000
370,000
253,000
-8,009
152,000
204,000
134,000
428,000
208,000
915,000
618,000
406,000
6,641
287,000
334,000
212,000
588,000
173,000 1,280,000
808,000
315,000
-9,965
160,000
261,000
162,000
454,000
188,000
937,000
652,000
329,000
-8,950
187,000
257,000
174,000
212,000
-18,000
581,000
356,000
211,000
3,537
134,000
161,000
109,000
530,000
372,000
934,000
691,000
460,000
-1,090
318,000
376,000
237,000
636,000
285,000 1,418,000
954,000
364,000
-11,662
175,000
291,000
169,000
867,000
656,000 1,490,000 1,129,000
251,000
-5,407
129,000
202,000
127,000
395,000
187,000
785,000
558,000
275,000
-8,548
140,000
210,000
133,000
547,000
360,000 1,034,000
764,000
330,000
-8,177
163,000
265,000
162,000
383,000
143,000
795,000
543,000
443,000
-4,582
302,000
367,000
214,000
905,000
648,000 1,773,000 1,290,000
526,000
-8,766
376,000
436,000
269,000
779,000
532,000 1,626,000 1,172,000
321,000
-11,219
154,000
254,000
165,000
246,000
59,000
590,000
413,000
343,000
3,569
280,000
279,000
175,000
899,000
754,000 1,728,000 1,296,000
354,800
-5,782
227,050
289,650
180,950
597,450
356,500 1,216,350
861,750
Note: the positive transport direction is southward
Table 3.2-3 (cont’d) Summary of computed net longshore sediment transport rates
for present GFDL wave climate.
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Average
Net Longshore Sediment Transport Rates for Present GFDL Wave Climate (m 3/year)
Section12 Section13 Section14 Section15 Section16 Section17 Section18 Section19 Section20 Section21 Section22
499,000 2,292,000
486,000 1,510,000
614,000 1,719,000
-602,000 -1,100,000 -1,045,000
-526,000
43,606
1,221,000 4,412,000 1,052,000 2,899,000 1,285,000 3,035,000
-724,000 -1,691,000 -1,562,000
-752,000
96,000
1,047,000 3,538,000
968,000 2,433,000 1,143,000 2,456,000
-659,000 -1,380,000 -1,283,000
-581,000
45,935
757,000 3,165,000
656,000 2,023,000
848,000 2,242,000
-663,000 -1,415,000 -1,291,000
-630,000
85,000
1,186,000 4,177,000 1,095,000 2,836,000 1,319,000 2,909,000
-801,000 -1,703,000 -1,579,000
-717,000
69,527
289,000 1,621,000
331,000 1,089,000
414,000 1,282,000
-518,000
-805,000
-775,000 -394,000
6,780
510,000 2,177,000
484,000 1,442,000
598,000 1,594,000
-563,000 -1,075,000 -1,010,000
-502,000
31,858
654,000 3,281,000
650,000 2,143,000
843,000 2,492,000
-920,000 -1,617,000 -1,526,000
-739,000
53,218
530,000 2,179,000
555,000 1,517,000
655,000 1,638,000
-607,000 -1,088,000 -1,035,000
-501,000
17,248
266,000 1,637,000
316,000 1,093,000
402,000 1,313,000
-520,000
-788,000
-751,000 -408,000
24,143
612,000 1,877,000
553,000 1,316,000
647,000 1,295,000
-358,000 -1,018,000
-953,000 -490,000
59,000
770,000 3,394,000
768,000 2,268,000
957,000 2,519,000
-853,000 -1,509,000 -1,417,000
-669,000
45,870
987,000 2,738,000
916,000 1,998,000 1,017,000 1,859,000
-486,000 -1,252,000 -1,189,000
-545,000
42,610
453,000 1,781,000
466,000 1,243,000
544,000 1,321,000
-465,000
-844,000
-802,000 -393,000
11,345
636,000 2,171,000
604,000 1,507,000
691,000 1,513,000
-496,000
-945,000
-894,000 -421,000
5,446
446,000 1,877,000
468,000 1,302,000
559,000 1,419,000
-502,000
-931,000
-888,000 -434,000
17,532
1,092,000 3,677,000 1,006,000 2,525,000 1,190,000 2,538,000
-677,000 -1,536,000 -1,425,000
-654,000
70,000
968,000 3,509,000
917,000 2,402,000 1,079,000 2,479,000
-689,000 -1,307,000 -1,233,000
-565,000
39,226
315,000 1,496,000
367,000 1,045,000
433,000 1,163,000
-414,000
-721,000
-684,000 -350,000
9,872
1,113,000 3,499,000
967,000 2,371,000 1,157,000 2,329,000
-506,000 -1,443,000 -1,309,000
-615,000
111,000
717,550 2,724,900
681,250 1,848,100
819,750 1,955,750
-601,150 -1,208,400 -1,132,550
-544,300
44,261
Note: the positive transport direction is southward
23
Table 3.2-4 Summary of computed gross longshore sediment transport rates for
present ECHAM wave climate.
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Average
Section1
105,000
151,000
108,000
92,522
119,000
121,000
150,000
91,430
123,000
100,000
73,892
99,937
111,000
97,783
103,000
115,000
112,000
121,000
97,582
96,062
109,410
Section2
13,057
17,497
12,460
8,839
8,693
13,689
12,842
10,138
17,108
8,226
10,297
7,155
13,405
16,942
11,257
10,005
9,920
9,096
8,449
12,297
11,569
Gross Longshore Sediment Transport Rates for Present GFDL Wave Climate (m 3/year)
Section3
Section4
Section5
Section6
Section7
Section8
Section9 Section10 Section11
348,000
17,129
271,000
276,000
191,000
514,000
481,000 1,054,000
753,000
509,000
21,963
479,000
426,000
281,000 1,079,000 1,048,000 2,097,000 1,589,000
429,000
17,575
316,000
340,000
214,000
917,000
822,000 1,741,000 1,294,000
321,000
9,425
290,000
264,000
179,000
710,000
609,000 1,429,000 1,024,000
480,000
11,345
380,000
389,000
244,000
999,000
863,000 1,975,000 1,458,000
332,000
18,814
236,000
255,000
175,000
337,000
384,000
672,000
489,000
307,000
18,269
262,000
217,000
168,000
585,000
490,000 1,063,000
789,000
421,000
10,817
301,000
346,000
223,000
628,000
642,000 1,315,000
875,000
349,000
21,722
250,000
266,000
180,000
540,000
521,000 1,002,000
739,000
336,000
11,314
225,000
259,000
181,000
313,000
321,000
676,000
470,000
228,000
11,527
153,000
172,000
118,000
617,000
603,000 1,038,000
810,000
469,000
8,172
338,000
381,000
244,000
694,000
581,000 1,455,000 1,031,000
391,000
17,478
254,000
297,000
187,000
914,000
873,000 1,538,000 1,187,000
275,000
20,031
193,000
206,000
141,000
483,000
467,000
878,000
666,000
296,000
14,343
204,000
216,000
147,000
634,000
573,000 1,121,000
862,000
361,000
13,220
238,000
272,000
183,000
444,000
462,000
859,000
618,000
468,000
12,312
355,000
374,000
231,000
940,000
812,000 1,806,000 1,334,000
536,000
11,922
423,000
438,000
277,000
851,000
830,000 1,678,000 1,246,000
332,000
12,813
208,000
256,000
175,000
331,000
339,000
662,000
497,000
357,000
12,873
299,000
290,000
185,000
958,000
880,000 1,793,000 1,368,000
377,250
14,653
283,750
297,000
196,200
674,400
630,050 1,292,600
954,950
Table 3.2-4 (cont’d) Summary of computed gross longshore sediment transport rates
for present GFDL wave climate.
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Average
Section12 Section13
632,000 2,324,000
1,360,000 4,435,000
1,108,000 3,557,000
863,000 3,207,000
1,230,000 4,188,000
405,000 1,641,000
668,000 2,222,000
744,000 3,299,000
631,000 2,187,000
386,000 1,663,000
728,000 1,915,000
860,000 3,405,000
1,049,000 2,747,000
570,000 1,799,000
733,000 2,210,000
531,000 1,896,000
1,139,000 3,694,000
1,062,000 3,517,000
416,000 1,515,000
1,186,000 3,534,000
815,050 2,747,750
Gross Longshore Sediment Transport Rates for Present GFDL Wave Climate (m 3/year)
Section14 Section15 Section16 Section17 Section18 Section19 Section20 Section21 Section22
615,000 1,592,000
741,000 1,747,000
704,000 1,101,000 1,045,000
526,000
83,214
1,158,000 2,941,000 1,391,000 3,059,000
916,000 1,697,000 1,563,000
752,000
148,000
1,011,000 2,464,000 1,186,000 2,479,000
721,000 1,380,000 1,283,000
581,000
85,582
761,000 2,093,000
956,000 2,276,000
733,000 1,415,000 1,293,000
630,000
136,000
1,125,000 2,853,000 1,345,000 2,923,000
856,000 1,705,000 1,580,000
717,000
95,523
414,000 1,123,000
483,000 1,306,000
530,000
807,000
778,000
394,000
59,123
630,000 1,528,000
744,000 1,643,000
606,000 1,076,000 1,011,000
502,000
92,071
709,000 2,170,000
883,000 2,515,000
975,000 1,618,000 1,527,000
739,000
98,630
612,000 1,530,000
703,000 1,649,000
645,000 1,089,000 1,037,000
501,000
53,405
410,000 1,140,000
496,000 1,338,000
551,000
791,000
755,000
408,000
74,147
653,000 1,381,000
750,000 1,333,000
519,000 1,021,000
958,000
490,000
111,000
819,000 2,287,000
998,000 2,533,000
880,000 1,509,000 1,419,000
669,000
85,414
963,000 2,024,000 1,063,000 1,872,000
672,000 1,255,000 1,191,000
545,000
75,875
546,000 1,272,000
622,000 1,340,000
480,000
844,000
803,000
393,000
57,873
689,000 1,571,000
781,000 1,546,000
505,000
945,000
894,000
421,000
64,152
526,000 1,337,000
617,000 1,436,000
548,000
931,000
890,000
434,000
66,405
1,040,000 2,551,000 1,223,000 2,562,000
744,000 1,537,000 1,426,000
654,000
106,000
964,000 2,415,000 1,121,000 2,489,000
728,000 1,308,000 1,233,000
565,000
79,077
432,000 1,081,000
499,000 1,188,000
447,000
721,000
686,000
350,000
67,322
1,032,000 2,426,000 1,227,000 2,371,000
604,000 1,444,000 1,311,000
615,000
152,000
755,450 1,888,950
891,450 1,980,250
668,200 1,209,700 1,134,150
544,300
89,541
24
Table 3.2-5 Summary of average net and gross longshore sediment transport rate
calculated from GENESIS for present period along Vietnam coast.
Area
Section1
Section2
Section3
Section4
Section5
Section6
Section7
Section8
Section9
Section10
Section11
Section12
Section13
Section14
Section15
Section16
Section17
Section18
Section19
Section20
Section21
Section22
Average Net Sediment Transport Rate *
ECHAM (1981-2000)
GFDL (1981-2000)
64,620
40,708
-867
-1,916
421,150
354,800
-4,252
-5,782
287,200
227,050
345,100
289,650
227,000
180,950
364,150
597,450
-7,500
356,500
948,150
1,216,350
564,800
861,750
424,600
717,550
2,754,100
2,724,900
452,150
681,250
1,758,650
1,848,100
591,750
819,750
2,150,600
1,955,750
-884,050
-601,150
-1,262,500
-1,208,400
-1,236,950
-1,132,550
-669,450
-544,300
26,372
44,261
Average Gross Sediment Transport Rate
ECHAM (1981-2000)
GFDL (1981-2000)
124,346
109,410
11,973
11,569
441,300
377,250
15,039
14,653
336,600
283,750
353,600
297,000
241,750
196,200
518,400
674,400
559,800
630,050
1,059,000
1,292,600
740,550
954,950
611,750
815,050
2,776,450
2,747,750
586,000
755,450
1,801,750
1,888,950
702,150
891,450
2,173,000
1,980,250
900,600
668,200
1,263,150
1,209,700
1,237,750
1,134,150
669,450
544,300
94,118
89,541
Note: (*) the positive transport direction is southward
Figure 3.2-1 Computed average net longshore sediment transport rates at 22
locations along Vietnam coast for present wave climate (1981-2000)
25
Figure 3.2-1 (cont’d) Computed average net longshore sediment transport rates at 22
locations along Vietnam coast for present wave climate (1981-2000)
Figure 3.2-1 (cont’d) Computed average net longshore sediment transport rates at 22
locations along Vietnam coast for present wave climate (1981-2000)
26
Figure 3.2-2 Computed average gross longshore sediment transport rates at 22
locations along Vietnam coast for present wave climate (1981-2000)
Figure 3.2-2 (cont’d) Computed average gross longshore sediment transport rates at
22 locations along Vietnam coast for present wave climate (1981-2000)
27
Figure 3.2-2 (cont’d) Computed average gross longshore sediment transport rates at
22 locations along Vietnam coast for present wave climate (1981-2000)
3.3
Modeling Results of Future Longshore Sediment Transport Rates
The computed annual net and gross longshore sediment transport rates from ECHAM and
GFDL wave climate for the future time slice (2081-2100) at the 22 costal sections along
Vietnam coast are summarized in Table 3.3-1 to 3.3-4, while the average net and gross
longshore sediment transport rates are summarized in Table 3.3-5. The estimates of future
average net and gross longshore sediment transport rates at these coastal locations
compared with the results from present wave climate (1981-2000) are shown in Figure 3.31 and 3.3-2, respectively. The corresponding plots of computed annual net and gross
longshore sediment transport rates are also shown in Appendix C.
From Table 3.3-1 to 3.3-4, the annual average results at 22 costal sections from future
ECHAM wave climate are in the range of 11,000-2,989,000 m3/year in total gross transport
and 400-1,493,000 m3/year in net transport in a northerly direction (at coastal section S4,
S9 and S18-S21) and 2,000-2,964,000 m3/year in net transport in a southerly direction (at
coastal section S1-S3, S5-S8, S10-S17 and S22). While, the results from future GFDL
wave climate are found to be in the range of 10,000-3,403,000 m3/year in total gross
transport and 1,400-1,645,000 m3/year in net transport in a northerly direction (at coastal
section S2, S4, S9, S18- S21) and 14,000-3,380,000 m3/year in net transport in a southerly
direction (at coastal section S1, S3, S5-S8, S10-S17 and S22).
Future change in net and gross longshore sediment transport rates at the 22 costal sections
are summarized in Table 3.3-6 to 3.3-7 and shown in Figure 3.3-3 to 3.3-4.
Analysis and comparison of simulated results of changes in longshore sediment transport
rates due to the present wave climate (1981 to 2000) and future (2081 to 2100) conditions
along the coast of Vietnam can be summarized as follows:
28
- Direction of computed net longshore sediment transport from ECHAM and
GFDL climate wave at most coastal section are mainly from north to south, except coastal
section S2, S4, S9, S18, S19, S20 and S21 where the net longshore sediment transport from
south to north.
- Changes of longshore sediment transport rates between present and future period
have both increasing and decreasing trends. For example, there are expected to increase in
net and gross longshore sediment transport rate at coastal section S1, S3, S5-S7, S13, S15
and S17-S21; and decrease at coastal section S4, S8, S10-S12, S14 and S16.
- The results from ECHAM and GFDL future wave climate provide the same
trend (increasing or decreasing) of longshore sediment transport changes for almost all
coastal sections (except coastal section S9 in net transport rate and coastal section S22 in
gross transport rate).
- At coastal section S2, S4, S9 and S22, there are large percentage differences of
net longshore sediment transport rates between the two different climate models (GFDL
and ECHAM). The large percentage changes between 1981-2000 and 2081-2100 can also
be found at these coastal sections in ECHAM, and at S1 and S9 in GFDL. This is because
their coastline orientations are almost perpendicular to the present day (1981-2000) wave
direction and therefore present net longshore sediment transport rates are very small (at
costal section S2, S4, S9 and S22).
29
Table 3.3-1 Summary of computed net longshore sediment transport rates for future
ECHAM wave climate.
Year
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
Average
Section1
72,000
75,000
112,000
125,000
140,000
126,000
54,000
82,000
142,000
77,000
67,000
48,000
109,000
98,000
73,000
44,619
120,000
78,000
129,000
55,000
91,331
Section2
1,438
7,215
-1,709
-3,891
12,504
4,543
-567
3,830
5,566
349
7,328
48
3,967
-1,758
2,095
3,015
-1,835
1,725
1,553
2,258
2,384
Net Longshore Sediment Transport Rates for Future ECHAM Wave Climate (m 3/year)
Section3
Section4
Section5
Section6
Section7
Section8
Section9 Section10 Section11
527,000
-2,947
384,000
449,000
289,000
344,000
-144,000 1,046,000
563,000
415,000
4,821
322,000
344,000
227,000
231,000
-86,000
748,000
429,000
633,000
-4,820
481,000
532,000
354,000
225,000
-405,000
955,000
394,000
598,000
-7,724
463,000
499,000
336,000
176,000
-259,000
848,000
423,000
542,000
10,132
511,000
451,000
309,000
475,000
165,000 1,329,000
835,000
676,000
1,597
566,000
581,000
391,000
251,000
-409,000 1,085,000
465,000
459,000
-2,999
284,000
385,000
246,000
176,000
-310,000
632,000
276,000
394,000
282
285,000
320,000
219,000
116,000
-187,000
550,000
257,000
780,000
3,561
666,000
675,000
446,000
277,000
-457,000 1,299,000
560,000
519,000
-2,464
368,000
441,000
295,000
88,000
-410,000
591,000
192,000
364,000
4,520
241,000
291,000
202,000
152,000
-166,000
544,000
272,000
331,000
-2,620
184,000
267,000
175,000
183,000
-123,000
552,000
303,000
491,000
1,967
406,000
403,000
277,000
434,000
32,000 1,178,000
691,000
570,000
-3,907
377,000
468,000
305,000
260,000
-206,000
875,000
454,000
441,000
-471
284,000
359,000
233,000
341,000
-72,000
900,000
518,000
341,000
1,207
192,000
276,000
176,000
240,000
-153,000
634,000
343,000
697,000
-5,648
542,000
590,000
380,000
483,000
-38,000 1,490,000
886,000
412,000
-694
298,000
337,000
230,000
271,000
-86,000
799,000
430,000
653,000
-707
465,000
537,000
363,000
117,000
-375,000
763,000
317,000
404,000
-1,540
261,000
336,000
227,000
154,000
-240,000
559,000
246,000
512,350
-423
379,000
427,050
284,000
249,700
-196,450
868,850
442,700
Note: the positive transport direction is southward
Table 3.3-1 (cont’d) Summary of computed net longshore sediment transport rates
for future ECHAM wave climate.
Year
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
Average
Net Longshore Sediment Transport Rates for Future ECHAM Wave Climate (m 3/year)
Section12 Section13 Section14 Section15 Section16 Section17 Section18 Section19 Section20 Section21 Section22
390,000 3,429,000
433,000 2,103,000
617,000 2,722,000 -1,139,000 -1,529,000 -1,521,000
-805,000
19,000
296,000 2,403,000
335,000 1,493,000
460,000 1,891,000
-759,000
-953,000
-942,000
-516,000
-1,545
234,000 3,648,000
328,000 2,200,000
534,000 3,047,000 -1,403,000 -1,697,000 -1,728,000
-923,000
-21,232
264,000 3,070,000
346,000 1,884,000
515,000 2,522,000 -1,094,000 -1,381,000 -1,374,000
-750,000
18,598
636,000 3,706,000
587,000 2,289,000
785,000 2,757,000
-909,000 -1,277,000 -1,224,000
-646,000
54,000
278,000 4,122,000
362,000 2,460,000
596,000 3,407,000 -1,458,000 -1,696,000 -1,719,000
-908,000
-16,870
157,000 2,408,000
270,000 1,515,000
391,000 2,056,000
-944,000 -1,118,000 -1,155,000
-623,000
-35,631
160,000 1,988,000
214,000 1,218,000
320,000 1,640,000
-755,000
-957,000
-950,000
-537,000
7,424
335,000 4,941,000
409,000 2,908,000
703,000 4,042,000 -1,696,000 -1,965,000 -1,973,000 -1,042,000
-3,242
79,000 2,618,000
176,000 1,564,000
319,000 2,262,000 -1,008,000 -1,091,000 -1,127,000
-627,000
-26,410
178,000 1,911,000
237,000 1,198,000
327,000 1,578,000
-725,000
-913,000
-923,000
-521,000
-12,899
201,000 1,788,000
272,000 1,158,000
356,000 1,473,000
-671,000
-891,000
-892,000
-497,000
-7,078
520,000 3,498,000
497,000 2,149,000
677,000 2,673,000 -1,064,000 -1,520,000 -1,493,000
-802,000
39,000
312,000 2,872,000
408,000 1,837,000
553,000 2,368,000 -1,012,000 -1,246,000 -1,259,000
-686,000
-1,555
374,000 2,705,000
430,000 1,736,000
564,000 2,153,000
-910,000 -1,267,000 -1,255,000
-679,000
15,000
225,000 2,093,000
307,000 1,349,000
403,000 1,724,000
-795,000 -1,055,000 -1,071,000
-582,000
-19,130
636,000 4,520,000
673,000 2,817,000
920,000 3,503,000 -1,333,000 -1,773,000 -1,734,000
-918,000
50,000
317,000 2,482,000
349,000 1,562,000
474,000 1,988,000
-842,000 -1,122,000 -1,115,000
-613,000
14,937
189,000 2,946,000
303,000 1,829,000
459,000 2,515,000 -1,127,000 -1,280,000 -1,308,000
-731,000
-14,479
154,000 2,130,000
219,000 1,314,000
323,000 1,798,000
-874,000 -1,140,000 -1,165,000
-631,000
-23,820
296,750 2,963,900
357,750 1,829,150
514,800 2,405,950 -1,025,900 -1,293,550 -1,296,400
-701,850
1,703
Note: the positive transport direction is southward
30
Table 3.3-2 Summary of computed gross longshore sediment transport rates for
future ECHAM wave climate.
Year
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
Average
Section1
134,000
131,000
155,000
162,000
158,000
158,000
117,000
141,000
212,000
134,000
135,000
108,000
143,000
120,000
108,000
93,938
181,000
126,000
185,000
137,000
141,947
Section2
9,034
16,962
9,334
7,189
17,373
10,843
9,040
13,920
10,610
9,071
14,364
8,441
11,511
4,529
8,393
9,505
10,842
9,678
10,117
11,911
10,633
Gross Longshore Sediment Transport Rates for Future ECHAM Wave Climate (m 3/year)
Section3
Section4
Section5
Section6
Section7
Section8
Section9
551,000
9,065
435,000
455,000
307,000
520,000
657,000
442,000
19,200
363,000
364,000
246,000
352,000
386,000
643,000
11,433
511,000
537,000
361,000
452,000
680,000
605,000
9,588
499,000
501,000
343,000
414,000
537,000
555,000
17,914
525,000
471,000
321,000
653,000
659,000
688,000
11,331
594,000
588,000
401,000
588,000
797,000
484,000
11,293
334,000
390,000
261,000
320,000
494,000
418,000
15,961
333,000
337,000
238,000
295,000
357,000
820,000
11,419
725,000
689,000
474,000
622,000
847,000
543,000
11,179
418,000
450,000
313,000
346,000
619,000
394,000
15,369
291,000
305,000
221,000
371,000
485,000
360,000
10,729
242,000
276,000
196,000
298,000
329,000
507,000
12,901
430,000
414,000
289,000
666,000
725,000
577,000
6,436
402,000
471,000
311,000
465,000
606,000
457,000
9,374
316,000
367,000
247,000
495,000
568,000
366,000
10,881
230,000
287,000
195,000
367,000
390,000
722,000
13,979
600,000
599,000
399,000
603,000
639,000
432,000
11,119
336,000
347,000
245,000
475,000
601,000
677,000
11,849
508,000
546,000
381,000
498,000
754,000
440,000
13,349
325,000
347,000
252,000
434,000
612,000
534,050
12,218
420,850
437,050
300,050
461,700
587,100
Section10 Section11
1,097,000
756,000
837,000
545,000
1,055,000
660,000
925,000
572,000
1,442,000
968,000
1,179,000
784,000
693,000
440,000
666,000
411,000
1,367,000
848,000
722,000
478,000
687,000
507,000
644,000
423,000
1,304,000
920,000
938,000
657,000
990,000
692,000
718,000
508,000
1,552,000
992,000
919,000
626,000
876,000
645,000
723,000
558,000
966,700
649,500
Table 3.3-2 (cont’d) Summary of computed gross longshore sediment transport rates
for future ECHAM wave climate.
Year
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
Average
Gross Longshore Sediment Transport Rates for Future ECHAM Wave Climate (m 3/year)
Section12 Section13 Section14 Section15 Section16 Section17 Section18 Section19 Section20 Section21 Section22
620,000 3,444,000
590,000 2,125,000
696,000 2,743,000 1,143,000 1,529,000 1,521,000
805,000
100,000
415,000 2,462,000
440,000 1,585,000
561,000 1,965,000
765,000
954,000
944,000
516,000
79,713
533,000 3,661,000
523,000 2,226,000
648,000 3,058,000 1,406,000 1,698,000 1,728,000
923,000
84,221
461,000 3,083,000
468,000 1,905,000
589,000 2,534,000 1,096,000 1,381,000 1,375,000
750,000
90,619
778,000 3,746,000
714,000 2,362,000
900,000 2,794,000
947,000 1,277,000 1,224,000
646,000
108,000
647,000 4,131,000
626,000 2,474,000
725,000 3,419,000 1,459,000 1,696,000 1,720,000
908,000
85,166
366,000 2,418,000
367,000 1,530,000
452,000 2,069,000
945,000 1,118,000 1,155,000
623,000
69,598
324,000 2,040,000
338,000 1,301,000
441,000 1,695,000
759,000
957,000
950,000
537,000
90,143
684,000 4,957,000
662,000 2,935,000
818,000 4,060,000 1,697,000 1,965,000 1,974,000 1,042,000
88,444
411,000 2,637,000
381,000 1,596,000
450,000 2,284,000 1,009,000 1,092,000 1,127,000
627,000
78,463
424,000 1,958,000
415,000 1,276,000
477,000 1,633,000
727,000
914,000
924,000
521,000
84,814
338,000 1,814,000
364,000 1,201,000
447,000 1,500,000
678,000
891,000
892,000
497,000
69,437
771,000 3,534,000
687,000 2,212,000
813,000 2,701,000 1,080,000 1,520,000 1,493,000
802,000
112,000
545,000 2,882,000
539,000 1,852,000
627,000 2,380,000 1,018,000 1,246,000 1,260,000
686,000
80,624
579,000 2,730,000
548,000 1,781,000
658,000 2,182,000
917,000 1,267,000 1,257,000
679,000
100,000
415,000 2,110,000
421,000 1,376,000
492,000 1,747,000
795,000 1,055,000 1,071,000
582,000
72,892
773,000 4,536,000
755,000 2,843,000
978,000 3,524,000 1,339,000 1,773,000 1,735,000
918,000
115,000
534,000 2,513,000
493,000 1,616,000
593,000 2,021,000
848,000 1,122,000 1,116,000
613,000
83,600
552,000 2,967,000
527,000 1,864,000
592,000 2,543,000 1,132,000 1,280,000 1,308,000
731,000
90,036
482,000 2,150,000
453,000 1,350,000
499,000 1,820,000
877,000 1,140,000 1,165,000
631,000
79,155
532,600 2,988,650
515,550 1,870,500
622,800 2,433,600 1,031,850 1,293,750 1,296,950
701,850
88,096
31
Table 3.3-3 Summary of computed net longshore sediment transport rates for future
GFDL wave climate.
Year
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
Average
Section1
53,000
54,000
32,000
110,000
60,000
76,000
81,000
42,000
70,000
137,000
76,000
36,000
36,000
103,000
72,000
77,000
107,000
151,000
58,000
52,098
74,155
Section2
2,075
-4,933
-8,016
1,314
577
499
-577
-4,437
6,240
1,170
-5,579
1,357
-2,667
2,049
-3,898
-6,201
3,449
-263
-3,658
-5,523
-1,351
Net Longshore Sediment Transport Rates for Future GFDL Wave Climate (m 3/year)
Section3
Section4
Section5
Section6
Section7
Section8
Section9 Section10 Section11
456,000
69
301,000
370,000
224,000
984,000
696,000 1,897,000 1,398,000
384,000
-8,508
224,000
307,000
199,000
312,000
65,000
739,000
485,000
357,000
-13,427
224,000
293,000
186,000
456,000
159,000 1,038,000
667,000
695,000
-1,181
542,000
594,000
387,000
277,000
-443,000 1,107,000
444,000
558,000
-5,029
419,000
482,000
303,000
474,000
-180,000 1,316,000
703,000
562,000
-3,225
451,000
485,000
315,000
354,000
-97,000 1,129,000
631,000
561,000
-3,834
432,000
481,000
317,000
229,000
-271,000
911,000
435,000
333,000
-8,494
196,000
274,000
181,000
217,000
-62,000
602,000
352,000
436,000
4,164
341,000
363,000
229,000
630,000
238,000 1,455,000
939,000
812,000
-844
697,000
701,000
453,000
755,000
85,000 2,034,000 1,192,000
572,000
-8,873
438,000
487,000
310,000
567,000
119,000 1,452,000
909,000
427,000
594
291,000
362,000
225,000
418,000
114,000 1,019,000
654,000
373,000
-6,055
224,000
307,000
192,000
514,000
218,000 1,094,000
742,000
659,000
368
520,000
565,000
361,000
364,000
-153,000 1,223,000
682,000
510,000
-7,459
352,000
426,000
277,000
284,000
-86,000
858,000
485,000
435,000
-10,816
252,000
349,000
228,000
117,000
-126,000
495,000
271,000
522,000
1,191
453,000
432,000
278,000
746,000
420,000 1,704,000 1,204,000
841,000
-1,748
731,000
732,000
488,000
291,000
-616,000 1,362,000
540,000
518,000
-6,539
326,000
426,000
266,000
426,000
43,000 1,086,000
677,000
322,000
-8,908
170,000
258,000
179,000
3,000 -270,000
207,000
51,000
516,650
-4,428
379,200
434,700
279,900
420,900
-7,350 1,136,400
673,050
Note: the positive transport direction is southward
Table 3.3-3 (cont’d) Summary of computed net longshore sediment transport rates
for future GFDL wave climate.
Year
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
Average
Net Longshore Sediment Transport Rates for Future GFDL Wave Climate (m 3/year)
Section12 Section13 Section14 Section15 Section16 Section17 Section18 Section19 Section20
1,162,000 4,068,000 1,053,000 2,753,000 1,215,000 2,794,000
-908,000 -1,688,000 -1,611,000
366,000 1,946,000
401,000 1,300,000
476,000 1,498,000
-585,000
-848,000
-845,000
525,000 2,602,000
524,000 1,702,000
649,000 1,945,000
-747,000 -1,166,000 -1,141,000
274,000 4,208,000
354,000 2,505,000
603,000 3,486,000 -1,553,000 -1,877,000 -1,900,000
476,000 4,398,000
509,000 2,651,000
752,000 3,464,000 -1,443,000 -1,872,000 -1,872,000
434,000 3,681,000
446,000 2,219,000
644,000 2,862,000 -1,146,000 -1,498,000 -1,489,000
275,000 3,283,000
343,000 1,990,000
525,000 2,685,000 -1,170,000 -1,450,000 -1,464,000
250,000 1,829,000
302,000 1,187,000
382,000 1,469,000
-671,000
-969,000
-973,000
727,000 3,853,000
677,000 2,420,000
871,000 2,824,000 -1,063,000 -1,649,000 -1,600,000
898,000 5,961,000
856,000 3,662,000 1,169,000 4,536,000 -1,703,000 -2,303,000 -2,277,000
687,000 4,080,000
680,000 2,569,000
890,000 3,080,000 -1,156,000 -1,679,000 -1,645,000
502,000 2,602,000
529,000 1,718,000
649,000 1,970,000
-755,000 -1,123,000 -1,106,000
594,000 2,673,000
586,000 1,778,000
703,000 1,970,000
-767,000 -1,305,000 -1,269,000
470,000 3,909,000
541,000 2,438,000
755,000 3,105,000 -1,203,000 -1,472,000 -1,464,000
349,000 2,643,000
402,000 1,682,000
529,000 2,114,000
-876,000 -1,184,000 -1,194,000
176,000 1,642,000
250,000 1,068,000
323,000 1,364,000
-593,000
-720,000
-729,000
929,000 4,435,000
835,000 2,782,000 1,060,000 3,146,000 -1,024,000 -1,611,000 -1,531,000
287,000 5,684,000
360,000 3,264,000
708,000 4,671,000 -1,971,000 -2,240,000 -2,266,000
505,000 3,015,000
545,000 1,958,000
679,000 2,326,000
-929,000 -1,283,000 -1,284,000
-14,000 1,174,000
74,000
724,000
120,000 1,071,000
-536,000
-577,000
-609,000
493,600 3,384,300
513,350 2,118,500
685,100 2,619,000 -1,039,950 -1,425,700 -1,413,450
Note: the positive transport direction is southward
32
Section21 Section22
-796,000
64,000
-450,000
-2,967
-586,000
24,371
-1,012,000
-7,057
-954,000
-6,337
-785,000
8,420
-769,000
-14,878
-516,000
-12,788
-816,000
44,000
-1,162,000
34,000
-851,000
40,000
-570,000
19,347
-658,000
41,000
-802,000
34,000
-629,000
917
-408,000
-14,872
-795,000
74,000
-1,201,000
-7,000
-659,000
-2,147
-350,000
-43,655
-738,450
13,618
Table 3.3-4 Summary of computed gross longshore sediment transport rates for
future GFDL wave climate.
Year
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
Average
Section1
119,000
114,000
120,000
156,000
139,000
159,000
139,000
105,000
113,000
188,000
144,000
136,000
110,000
155,000
137,000
116,000
144,000
174,000
142,000
89,312
134,966
Section2
11,312
9,047
11,558
8,219
13,450
13,867
10,302
9,667
12,796
7,658
8,485
15,499
9,050
9,733
8,812
8,485
10,370
5,470
8,346
6,467
9,930
Gross Longshore Sediment Transport Rates for Future GFDL Wave Climate (m 3/year)
Section3
Section4
Section5
Section6
Section7
Section8
Section9 Section10 Section11
484,000
13,527
348,000
381,000
243,000 1,096,000 1,110,000 1,956,000 1,514,000
398,000
12,184
273,000
311,000
209,000
447,000
466,000
851,000
631,000
379,000
16,419
301,000
299,000
202,000
530,000
475,000 1,112,000
751,000
713,000
9,211
576,000
600,000
399,000
528,000
814,000 1,162,000
724,000
586,000
15,091
482,000
489,000
321,000
579,000
668,000 1,365,000
856,000
593,000
16,618
507,000
496,000
335,000
518,000
561,000 1,226,000
795,000
582,000
12,787
482,000
489,000
332,000
435,000
607,000 1,001,000
634,000
353,000
13,545
258,000
278,000
195,000
377,000
399,000
697,000
494,000
459,000
13,784
372,000
377,000
247,000
725,000
645,000 1,543,000 1,065,000
835,000
9,221
738,000
710,000
470,000 1,079,000 1,200,000 2,107,000 1,526,000
588,000
11,440
488,000
491,000
322,000
704,000
704,000 1,507,000 1,053,000
463,000
21,374
352,000
368,000
241,000
481,000
401,000 1,084,000
730,000
401,000
12,084
289,000
314,000
213,000
654,000
653,000 1,168,000
879,000
685,000
12,037
562,000
576,000
379,000
469,000
494,000 1,288,000
791,000
531,000
12,148
407,000
432,000
293,000
515,000
582,000
981,000
697,000
443,000
12,638
302,000
352,000
238,000
279,000
375,000
588,000
433,000
538,000
11,649
482,000
445,000
291,000
844,000
678,000 1,813,000 1,330,000
847,000
6,747
746,000
736,000
493,000
570,000 1,003,000 1,436,000
843,000
544,000
11,241
386,000
433,000
283,000
529,000
577,000 1,146,000
793,000
328,000
9,722
208,000
259,000
185,000
189,000
323,000
350,000
261,000
537,500
12,673
427,950
441,800
294,550
577,400
636,750 1,219,050
840,000
Table 3.3-4 (cont’d) Summary of computed gross longshore sediment transport rates
for future GFDL wave climate.
Year
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
Average
Gross Longshore Sediment Transport Rates for Future GFDL Wave Climate (m 3/year)
Section12 Section13 Section14 Section15 Section16 Section17 Section18 Section19 Section20 Section21 Section22
1,298,000 4,082,000 1,133,000 2,773,000 1,278,000 2,808,000
940,000 1,690,000 1,613,000
796,000
121,000
535,000 1,966,000
514,000 1,334,000
580,000 1,520,000
596,000
848,000
845,000
450,000
77,933
615,000 2,627,000
597,000 1,744,000
721,000 1,970,000
775,000 1,167,000 1,143,000
586,000
77,290
593,000 4,227,000
572,000 2,535,000
707,000 3,512,000 1,558,000 1,878,000 1,900,000 1,012,000
99,065
663,000 4,409,000
615,000 2,668,000
809,000 3,479,000 1,459,000 1,873,000 1,873,000
954,000
90,282
619,000 3,706,000
568,000 2,260,000
747,000 2,889,000 1,154,000 1,498,000 1,489,000
785,000
96,633
508,000 3,295,000
509,000 2,016,000
623,000 2,700,000 1,175,000 1,451,000 1,464,000
769,000
79,867
413,000 1,843,000
412,000 1,215,000
473,000 1,484,000
672,000
970,000
973,000
516,000
68,065
858,000 3,877,000
785,000 2,460,000
964,000 2,846,000 1,069,000 1,649,000 1,600,000
816,000
105,000
1,275,000 5,973,000 1,126,000 3,678,000 1,302,000 4,553,000 1,725,000 2,303,000 2,278,000 1,162,000
133,000
860,000 4,086,000
783,000 2,581,000
953,000 3,089,000 1,188,000 1,681,000 1,647,000
851,000
115,000
590,000 2,620,000
588,000 1,749,000
710,000 1,985,000
769,000 1,123,000 1,106,000
570,000
70,434
751,000 2,689,000
679,000 1,804,000
778,000 1,990,000
789,000 1,305,000 1,272,000
658,000
101,000
603,000 3,924,000
615,000 2,463,000
819,000 3,126,000 1,210,000 1,473,000 1,466,000
802,000
103,000
587,000 2,651,000
562,000 1,696,000
647,000 2,123,000
884,000 1,184,000 1,195,000
629,000
73,326
359,000 1,670,000
373,000 1,115,000
424,000 1,396,000
595,000
721,000
730,000
408,000
69,887
1,047,000 4,485,000
947,000 2,866,000 1,176,000 3,199,000 1,033,000 1,612,000 1,531,000
795,000
144,000
673,000 5,694,000
635,000 3,279,000
809,000 4,684,000 1,977,000 2,240,000 2,266,000 1,201,000
101,000
647,000 3,024,000
622,000 1,974,000
738,000 2,335,000
954,000 1,284,000 1,284,000
659,000
71,653
221,000 1,202,000
226,000
769,000
257,000 1,103,000
536,000
577,000
610,000
350,000
58,757
685,750 3,402,500
643,050 2,148,950
775,750 2,639,550 1,052,900 1,426,350 1,414,250
738,450
92,810
33
Table 3.3-5 Summary of average net and gross longshore sediment transport rate
calculated from GENESIS for future period along the Vietnam coast.
Area
Section1
Section2
Section3
Section4
Section5
Section6
Section7
Section8
Section9
Section10
Section11
Section12
Section13
Section14
Section15
Section16
Section17
Section18
Section19
Section20
Section21
Section22
Average Net Sediment Transport Rate *
ECHAM (2081-2100) GFDL (2081-2100)
Difference
3
3
3
(m /yr)
(m /yr)
(m /yr)
(%)
91,331
74,155
-17,176
-20.8
2,384
-1,351
-3,735
-723.4
512,350
516,650
4,300
0.8
-423
-4,428
-4,005
165.1
379,000
379,200
200
0.1
427,050
434,700
7,650
1.8
284,000
279,900
-4,100
-1.5
249,700
420,900
171,200
51.1
-196,450
-7,350
189,100
-185.6
868,850
1,136,400
267,550
26.7
442,700
673,050
230,350
41.3
296,750
493,600
196,850
49.8
2,963,900
3,384,300
420,400
13.2
357,750
513,350
155,600
35.7
1,829,150
2,118,500
289,350
14.7
514,800
685,100
170,300
28.4
2,405,950
2,619,000
213,050
8.5
-1,025,900
-1,039,950
-14,050
1.4
-1,293,550
-1,425,700
-132,150
9.7
-1,296,400
-1,413,450
-117,050
8.6
-701,850
-738,450
-36,600
5.1
1,703
13,618
11,914
155.5
Average Gross Sediment Transport Rate
ECHAM (2081-2100) GFDL (2081-2100)
Difference
3
3
3
(m /yr)
(m /yr)
(m /yr)
(%)
141,947
134,966
-6,981
-5.0
10,633
9,930
-704
-6.8
534,050
537,500
3,450
0.6
12,218
12,673
455
3.7
420,850
427,950
7,100
1.7
437,050
441,800
4,750
1.1
300,050
294,550
-5,500
-1.8
461,700
577,400
115,700
22.3
587,100
636,750
49,650
8.1
966,700
1,219,050
252,350
23.1
649,500
840,000
190,500
25.6
532,600
685,750
153,150
25.1
2,988,650
3,402,500
413,850
13.0
515,550
643,050
127,500
22.0
1,870,500
2,148,950
278,450
13.9
622,800
775,750
152,950
21.9
2,433,600
2,639,550
205,950
8.1
1,031,850
1,052,900
21,050
2.0
1,293,750
1,426,350
132,600
9.7
1,296,950
1,414,250
117,300
8.7
701,850
738,450
36,600
5.1
88,096
92,810
4,713
5.2
Note: (*) the positive transport direction is southward
Table 3.3-6 Future change in computed average net longshore sediment transport
rate from ECHAM and GFDL.
Area
Section1
Section2
Section3
Section4
Section5
Section6
Section7
Section8
Section9
Section10
Section11
Section12
Section13
Section14
Section15
Section16
Section17
Section18
Section19
Section20
Section21
Section22
Present (1981-2000)
3
(m /yr)
64,620
-867
421,150
-4,252
287,200
345,100
227,000
364,150
-7,500
948,150
564,800
424,600
2,754,100
452,150
1,758,650
591,750
2,150,600
-884,050
-1,262,500
-1,236,950
-669,450
26,372
ECHAM Wave Climate
Future (2081-2100)
3
(m /yr)
91,331
2,384
512,350
-423
379,000
427,050
284,000
249,700
-196,450
868,850
442,700
296,750
2,963,900
357,750
1,829,150
514,800
2,405,950
-1,025,900
-1,293,550
-1,296,400
-701,850
1,703
Change
3
(m /yr)
(%)
26,711
41.3
3,250
-375.0
91,200
21.7
3,829
-90.1
91,800
32.0
81,950
23.7
57,000
25.1
-114,450
-31.4
-188,950
2,519.3
-79,300
-8.4
-122,100
-21.6
-127,850
-30.1
209,800
7.6
-94,400
-20.9
70,500
4.0
-76,950
-13.0
255,350
11.9
-141,850
16.0
-31,050
2.5
-59,450
4.8
-32,400
4.8
-24,669
-93.5
34
Present (1981-2000)
3
(m /yr)
40,708
-1,916
354,800
-5,782
227,050
289,650
180,950
597,450
356,500
1,216,350
861,750
717,550
2,724,900
681,250
1,848,100
819,750
1,955,750
-601,150
-1,208,400
-1,132,550
-544,300
44,261
GFDL Wave Climate
Future (2081-2100)
3
(m /yr)
74,155
-1,351
516,650
-4,428
379,200
434,700
279,900
420,900
-7,350
1,136,400
673,050
493,600
3,384,300
513,350
2,118,500
685,100
2,619,000
-1,039,950
-1,425,700
-1,413,450
-738,450
13,618
Change
3
(m /yr)
33,447
565
161,850
1,355
152,150
145,050
98,950
-176,550
-363,850
-79,950
-188,700
-223,950
659,400
-167,900
270,400
-134,650
663,250
-438,800
-217,300
-280,900
-194,150
-30,643
(%)
82.2
-29.5
45.6
-23.4
67.0
50.1
54.7
-29.6
-102.1
-6.6
-21.9
-31.2
24.2
-24.6
14.6
-16.4
33.9
73.0
18.0
24.8
35.7
-69.2
Table 3.3-7 Future change in computed average gross longshore sediment transport
rate from ECHAM and GFDL.
Area
Section1
Section2
Section3
Section4
Section5
Section6
Section7
Section8
Section9
Section10
Section11
Section12
Section13
Section14
Section15
Section16
Section17
Section18
Section19
Section20
Section21
Section22
Present (1981-2000)
3
(m /yr)
124,346
11,973
441,300
15,039
336,600
353,600
241,750
518,400
559,800
1,059,000
740,550
611,750
2,776,450
586,000
1,801,750
702,150
2,173,000
900,600
1,263,150
1,237,750
669,450
94,118
ECHAM Wave Climate
Future (2081-2100)
3
(m /yr)
141,947
10,633
534,050
12,218
420,850
437,050
300,050
461,700
587,100
966,700
649,500
532,600
2,988,650
515,550
1,870,500
622,800
2,433,600
1,031,850
1,293,750
1,296,950
701,850
88,096
Change
3
(m /yr)
17,600
-1,340
92,750
-2,820
84,250
83,450
58,300
-56,700
27,300
-92,300
-91,050
-79,150
212,200
-70,450
68,750
-79,350
260,600
131,250
30,600
59,200
32,400
-6,022
(%)
14.2
-11.2
21.0
-18.8
25.0
23.6
24.1
-10.9
4.9
-8.7
-12.3
-12.9
7.6
-12.0
3.8
-11.3
12.0
14.6
2.4
4.8
4.8
-6.4
Present (1981-2000)
3
(m /yr)
109,410
11,569
377,250
14,653
283,750
297,000
196,200
674,400
630,050
1,292,600
954,950
815,050
2,747,750
755,450
1,888,950
891,450
1,980,250
668,200
1,209,700
1,134,150
544,300
89,541
GFDL Wave Climate
Future (2081-2100)
3
(m /yr)
134,966
9,930
537,500
12,673
427,950
441,800
294,550
577,400
636,750
1,219,050
840,000
685,750
3,402,500
643,050
2,148,950
775,750
2,639,550
1,052,900
1,426,350
1,414,250
738,450
92,810
Change
3
(m /yr)
25,555
-1,639
160,250
-1,980
144,200
144,800
98,350
-97,000
6,700
-73,550
-114,950
-129,300
654,750
-112,400
260,000
-115,700
659,300
384,700
216,650
280,100
194,150
3,269
Figure 3.3-1 Estimates of present and future average net longshore sediment
transport rates at 22 costal sections
35
(%)
23.4
-14.2
42.5
-13.5
50.8
48.8
50.1
-14.4
1.1
-5.7
-12.0
-15.9
23.8
-14.9
13.8
-13.0
33.3
57.6
17.9
24.7
35.7
3.7
Figure 3.3-1 (cont’d) Estimates of present and future average net longshore sediment
transport rates at 22 costal sections
Figure 3.3-1 (cont’d) Estimates of present and future average net longshore sediment
transport rates at 22 costal sections
36
Figure 3.3-2 Estimates of present and future average gross longshore sediment
transport rates at 22 costal sections
Figure 3.3-2 (cont’d) Estimates of present and future average gross longshore
sediment transport rates at 22 costal sections
37
Figure 3.3-2 (cont’d) Estimates of present and future average gross longshore
sediment transport rates at 22 costal sections
Figure 3.3-3 Future change in average net longshore sediment transport rates at
the 22 costal sections along Vietnam Coast
38
Figure 3.3-4 Future change in average gross longshore sediment transport rates at
the 22 costal sections along Vietnam Coast
39
CHAPTER 4
CONCLUSIONS
1. The present study has estimated the present and future longshore sediment transport
rates at 22 coastal sections along Vietnam coast using a one-line longshore transport model
(GENESIS), which has been forced by ECHAM and GFDL wave climates determined in
the previous CCWaves-Vietnam study for two time span of 1981-2000 and 2081-2100.
2. GENESIS model calibration was conducted by applying calibration parameters values
for 𝑘1 and 𝑘2 from previous research studies. Calibration parameters 𝑘1 and 𝑘2 with values
of 0.75-0.80 and 0.40-0.50, give moderate and good quantitative agreement between the
computed results and the reported values.
3. The computed results indicate that the volume and direction of longshore sediment
transport along the coast of Vietnam is rather variable. For present conditions, the annual
average results from ECHAM and GFDL wave climate at 22 costal sections are found to
be in the range of 11,000-2,748,000 m3/year in total gross transport and 1,400-1,426,000
m3/year in net transport in a northerly direction (at coastal section S2, S4 and S18-S21) and
35,000-2,740,000 m3/year in net transport in a southerly direction (at coastal section S1,
S3, S5-S17 and S22). For future conditions, the annual average results at 22 costal sections
are in the range of 10,000-3,403,000 m3/year in total gross transport and 2,000-1,569,000
m3/year in net transport in a northerly direction (at coastal section S4, S9, S18-S21) and
500-3,174,000 m3/year in net transport in a southerly direction (at coastal section S1-S3,
S5-S8, S10-S17 and S22).
4. For the two time span of 1981-2000 and 2081-2100, directions of net longshore
sediment transport at almost all coastal sections are the same, except at coastal sections S2,
S4, S9 and S22. In these sections the net transport in both time spans are variable in
different years but net sediment transport due to climate change effect (time span of 20812100) at S2 and S4 is turning more toward the south and at S9 and S22 is changing more
toward the north.
5. The estimated results of longshore sediment transport rates from present (1981-2000)
and future (2081-2100) CC modified wave climate show significant changes in net and
gross longshore sediment transport rates along the coast of Vietnam.
40
Table 4.1 Changes in net sediment longshore sediment transport at 22 coastal sections
along the Vietnam coastline due to climate change.
Coastal section
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
S12
S13
S14
S15
S16
S17
S18
S19
S20
S21
S22
Description
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 62%, in the order of 30,000 m3/yr
There is no dominant direction of net longshore sediment transport in this section it will remain the
same upto 2100 but with more tendency toward the south. The magnitude will decreases with about 7%
in order of 1,000 m3/year in the southerly direction
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 34%, in the order of 125,000 m3/yr
There is no dominant direction of net longshore sediment transport in this section it will remain the
same upto 2100 but with more tendency toward the south. The magnitude will decreases with about
28% in order of 2,000 m3/year in the southerly direction
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 50%, in the order of 122,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 37%, in the order of 113,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 40%, in the order of 78,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 30%, in the order of 145,000 m3/yr
There is no dominant direction of net longshore sediment transport in this section it will remain the
same upto 2100 but with more tendency toward the north. The magnitude will increases with about
240% in order of 162,000 m3/year in the northerly direction
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 7%, in the order of 80,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 22%, in the order of 155,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 30%, in the order of 176,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 16%, in the order of 434,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 23%, in the order of 131,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 9%, in the order of 170,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport decreases by 15%, in the order of 105,000 m3/yr
The net longshore sediment transport is toward the south at present and will remain towards the south
upto 2100. The magnitude of net annual transport increases by 23%, in the order of 460,000 m3/yr
The net longshore sediment transport is toward the north at present and will remain towards the north
upto 2100. The magnitude of net annual transport increases by 45%, in the order of 290,000 m3/yr
The net longshore sediment transport is toward the north at present and will remain towards the north
upto 2100. The magnitude of net annual transport increases by 10%, in the order of 124,000 m3/yr
The net longshore sediment transport is toward the north at present and will remain towards the north
upto 2100. The magnitude of net annual transport increases by 15%, in the order of 170,000 m3/yr
The net longshore sediment transport is toward the north at present and will remain towards the north
upto 2100. The magnitude of net annual transport increases by 20%, in the order of 113,000 m3/yr
There is no dominant direction of net longshore sediment transport in this section it will remain the
same upto 2100 but with more tendency toward the north. The magnitude will increases with about
60% in order of 5,000 m3/year in the northerly direction
41
REFERENCES
Cat, N.N., Tien, P.H., Sam, D.D. & N.N. Bien., 2006. Status of coastal erosion of VietNam
and proposed measures for protection. FAO Asia Pacific.
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An Inlet, Vietnam. Master Thesis, Lund University.
Hung, N.M., Dien. D.C., 2006. Effects of the storm number 7 (DAMREY) on the sea dyke
system of Nam Dinh Province, J. Mar. Sci. 4 (T6).
Lam, N.T., 2009. Hydrodynamics and morphodynamics of a seasonally force tidal inlet
system. Ph.D. Thesis, Delft University of Technology.
Mazda, Y., Magi, M., Nanao, H., Kogo, M., Miyagi, T., Kanazawa, N. and Kobashi, D,
2002. Coastal Erosion due to longterm human impact on mangrove forests.
Wetlands Ecology and Management. Vol. 10: 1 -9.
Hanson,H. and Kraus, N.C., 1989. GENESIS: Generalized model for simulating shoreline
change. Technical Report CERC 89-19. U.S. Army Engineer Waterways
Experiment Station, Coastal Engineering Research Center, Vicksburg, Mississippi,
185p.
Q. T. Doan, Y.C. Chen, T.T. Quach and P.K. Mishra., 2013. Numerical modeling in shore
line evolution prediction: Case study of Tat Dike, Vietnam. International Journal
of Earth Sciences and Engineering, Vol.6, pp 1251-1259.
Tien, T.Q., 2004. Use of hindcast wave field by WAM model for calculation of sediment
transport in littoral zone of Vietnam Central. The 14th OMISAR Workshop on
Ocean Models.Taipei, Taiwan.
Young, R.S.; Pilkey, D.H.; Bush, D.M.; and Thieler, E.R., 1995. A discussion of the
Generalized Model for Simulating Shoreline Change (GENESIS). Journal of
Coastal Research, 11(3), 875-886.
42
Appendix A
Result of Present Longshore Sediment Transport Rates
43
N
N
Calm
64.22 %
Calm
66.94 %
Palette
Palette
Coastal Section S1
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
N
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S2
N
Calm
60.29 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Calm
60.29 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S4
Coastal Section S3
N
N
Calm
56.15 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
Calm
62.82 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S6
Coastal Section S5
N
N
Calm
70.65 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S7
Calm
52.43 %
Palette
Coastal Section S8
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Figure A-1 Wave rose diagrams from ECHAM climate model for the future period
(2081-2100)
44
N
N
Calm
49.91 %
Calm
49.98 %
Palette
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S10
Coastal Section S9
N
N
Calm
51.25 %
Calm
49.62 %
Palette
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Coastal Section S11
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S12
N
N
Calm
51.25 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
Calm
49.82 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S14
Coastal Section S13
Figure A-1 (cont’d) Wave rose diagrams from ECHAM climate model for the future
period (2081-2100)
45
N
N
Palette
Calm
49.82 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Calm
49.27 %
Coastal Section S15
Palette
Coastal Section S16
N
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
N
Palette
Calm
49.24 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
Calm
50.90 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S18
Coastal Section S17
N
N
Palette
Calm
51.31 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
Calm
51.58 %
5%
Coastal Section S19
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S20
N
N
Calm
55.65 %
Calm
64.24 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S22
Coastal Section S21
Figure A-1 (cont’d) Wave rose diagrams from ECHAM climate model for the future
period (2081-2100)
46
N
N
Calm
66.91 %
Calm
63.94 %
Palette
Palette
Coastal Section S1
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S2
N
N
Calm
59.91 %
Calm
59.91 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S4
Coastal Section S3
N
N
Calm
55.36 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S5
Palette
Calm
62.83 %
5%
N
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S6
N
Calm
70.80 %
Calm
52.65 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S8
Coastal Section S7
Figure A-2 Wave rose diagrams from GFDL climate model for the future period
(2081-2100)
47
N
N
Calm
47.80 %
Calm
50.21 %
Palette
5%
Palette
Above 2.50
2.00 - 2.50
1.50 - 2.00
1.00 - 1.50
0.50 - 1.00
Below 0.50
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S10
Coastal Section S9
N
N
Calm
49.91 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Calm
51.19 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S12
Coastal Section S11
N
N
Calm
51.19 %
Calm
50.10 %
Palette
5%
Palette
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S14
Coastal Section S13
Figure A-2 (cont’d) Wave rose diagrams from GFDL climate model for the future
period (2081-2100)
48
N
N
Calm
50.10 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Calm
49.86 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S16
Coastal Section S15
N
N
Palette
Calm
49.75 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
Calm
50.80 %
5%
Coastal Section S17
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S18
N
N
Palette
Calm
50.58 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
Calm
50.86 %
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S20
Coastal Section S19
N
N
Calm
55.22 %
Calm
64.91 %
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Palette
5%
Above 2.5
2.0 - 2.5
1.5 - 2.0
1.0 - 1.5
0.5 - 1.0
Below 0.5
Coastal Section S22
Coastal Section S21
Figure A-2 (cont’d) Wave rose diagrams from GFDL climate model for the future
period (2081-2100)
49
Appendix B
Result of Present Longshore Sediment Transport Rates
50
Figure B-1 Computed annual net longshore sediment transport rates for
present wave climate (1981-2000)
51
Figure B-1 (cont’d) Computed annual net longshore sediment transport rates for
present wave climate (1981-2000)
52
Figure B-1 (cont’d) Computed annual net longshore sediment transport rates for
present wave climate (1981-2000)
53
Figure B-1 (cont’d) Computed annual net longshore sediment transport rates for
present wave climate (1981-2000)
54
Figure B-1 (cont’d) Computed annual net longshore sediment transport rates for
present wave climate (1981-2000)
Figure B-2 Computed annual gross longshore sediment transport rates for
present wave climate (1981-2000)
55
Figure B-2 (cont’d) Computed annual gross longshore sediment transport rates for
present wave climate (1981-2000)
56
Figure B-2 (cont’d) Computed annual gross longshore sediment transport rates for
present wave climate (1981-2000)
57
Figure B-2 (cont’d) Computed annual gross longshore sediment transport rates for
present wave climate (1981-2000)
58
Figure B-2 (cont’d) Computed annual gross longshore sediment transport rates for
present wave climate (1981-2000)
59
Appendix C
Result of Future Longshore Sediment Transport Rates
60
Figure C-1 Computed annual net longshore sediment transport rates for
present (1981-2000) and future wave climate (2081-2100)
61
Figure C-1 (cont’d) Computed annual net longshore sediment transport rates for
present (1981-2000) and future wave climate (2081-2100)
62
Figure C-1 (cont’d) Computed annual net longshore sediment transport rates for
present (1981-2000) and future wave climate (2081-2100)
63
Figure C-1 (cont’d) Computed annual net longshore sediment transport rates for
present (1981-2000) and future wave climate (2081-2100)
64
Figure C-1 (cont’d) Computed annual net longshore sediment transport rates for
present (1981-2000) and future wave climate (2081-2100)
Figure C-2 Computed annual gross longshore sediment transport rates for
present (1981-2000) and future wave climate (2081-2100)
65
Figure C-2 (cont’d) Computed annual gross longshore sediment transport rates for
present (1981-2000) and future wave climate (2081-2100)
66
Figure C-2 (cont’d) Computed annual gross longshore sediment transport rates for
present (1981-2000) and future wave climate (2081-2100)
67
Figure C-2 (cont’d) Computed annual gross longshore sediment transport rates for
present (1981-2000) and future wave climate (2081-2100)
68
Figure C-2 (cont’d) Computed annual gross longshore sediment transport rates for
present (1981-2000) and future wave climate (2081-2100)
69