predictability of seabed change due to underwater sand mining in coastal waters of korea...
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Predictability of Seabed Change due to UnderwaPredictability of Seabed Change due to Underwater Sand Mining in Coastal Waters of Korter Sand Mining in Coastal Waters of Koreaea
Chang S. Kim, Hak Soo Lim and Jinah KimChang S. Kim, Hak Soo Lim and Jinah Kim
Korea Ocean R&D InstituteKorea Ocean R&D InstituteCoastal Engineering DivisionCoastal Engineering Division
1270 Sa2Dong Ansan 426-744 South Korea.1270 Sa2Dong Ansan 426-744 South Korea.
[email protected]@kordi.re.kr
2006ROMS/TOMS Europe Nov 6-8, 2006
Alcala De Henares Spain
AbstractAbstract Numerical modeling and field experiment have been conducted to predict the seabed change due to underwater sand mining in coastal waters of Korea. The macro-tidal Kyunggi Bay is approximately 20,000 km2, where underwater sand has been extracted approximately more than 20 million m3 annually. Suspended sediment (SS) transport in the water column and sea bed has been a critically important issue to many concerns. In this study, we present the numerical prediction of sediment transport processes such as SS dispersion and consequent change in sediment types in sea bottom. We use full 3-D model ROMS to implement the sediment dynamics by adopting the extensively observed field data associated with modeling inputs and model validation.
Seabed Sand Mining Area Seabed Sand Mining Area in Kyunggi Bay, Koreain Kyunggi Bay, Korea
(Songap)선갑(Pungdo)풍도 (Kukwado)국화도(Paega)백아
(Kurop)굴업 (Tokchok)덕적 (Yonghung)영흥
(Yigok)이곡
8 8
44
66
77
11
22
33
55
99
283858688898283858688898
243454648494243454648494
263656668696263656668696
273757678797273757678797
103040607090103040607090
21315161819121
3151618191
223252628292223252628292
233353638393233353638393
253555658595253555658595
293959698999293959698999
48 7878 184818
72 72
71
80 80
77 77
76 76
74 74
7373
7575
7979
14441444
16461646
17471747
20502050
114111
4112421242
13431343
15451545
19491949
148 118128148118128
114124144114124144
116126146116126146
117127147117127147
100120130150100120130150
111121141111121141
112122142112122142
113123143113123143
115125145115125145
119129149119129149
138 108138108
104134104134
106136106136
107137107137
110140110140
101131101131
102132102132
103133103133
105135105135
109139109139
3 333
2222
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9999
1111
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3333
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43 33433343334333
3242324232423242
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3141314131413141
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3747374737473747
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3343334333433343
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3646364636463646
3747374737473747
3848384838483848
4050405040504050
3444344434443444
3646364636463646
3848384838483848
4050405040504050
1323637383132363738313236373831323637383 5393539353935393
15
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1929697989192969798919296979891929697989
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1525657585152565758515256575851525657585
17276777871727677787172767778717276777
19
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60 60 60 60
98 58 98 58 98 58 98 58
96 56 96 56 96 56 96 56
94 54 94 54 94 54 94 54
60 60 60 60
98 58 98 58 98 58 98 58
97 57 97 57 97 57 97 57
96 56 96 56 96 56 96 56
95 55 95 55 95 55 95 55
93 53 93 53 93 53 93 53
91 51 91 51 91 51 91 51
99 59 99 59 99 59 99 59
97 57 97 57 97 57 97 57
95 55 95 55 95 55 95 55
92 52 92 52 92 52 92 52
91 51 91 51 91 51 91 51
99 59 99 59 99 59 99 59
94 54 94 54 94 54 94 54
92 52 92 52 92 52 92 52
90 80 70 30 20 10 90 80 70 30 20 10 90 80 70 30 20 10 90 80 70 30 20 10
88 78 68 28 18 88 78 68 28 18 88 78 68 28 18 88 78 68 28 18
86 76 66 26
69
86 76 66 26 16 86 76 66 26 16 86 76 66 26 16
84 74 64 24 14 84 74 64 24 14 84 74 64 24 14 84 74 64 24 14
90 80 70 30 20 10 90 80 70 30 20 10 90 80 70 30 20 10 90 80 70 30 20 10
88 78 68 28 18 88 78 68 28 18 88 78 68 28 18 88 78 68 28 18
87 77 67 27 17 87 77 67 27 17 87 77 67 27 17 87 77 67 27 17
86 76 66 26 16 86 76 66 26 16 86 76 66 26 16 86 76 66 26 16
85 75 65 25 15 85 75 65 25
87
85 75 65 25 15 85 75 65 25 15
83 73 63 23 13 83 73 63 23 13 83 73 63 23 13 83 73 63 23 13
81 71 61 21 11 81 71 61 21 11 81 71 61 21 11 81 71 61 21 11
89 79 69 29 19 89 79 69 29 19 89 79
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124
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105135145105135145105135145105135145
106136146106136146106136146106136146
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100100100100
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Depth (m)
Numerical Model Grid for Kyunggi Bay
125.4 125.6 125.8 126.0 126.2 126.4 126.6 126.8 127.0
36.8
37.0
37.2
37.4
37.6
37.8
38.0
125.4 125.6 125.8 126.0 126.2 126.4 126.6 126.8 127.0
36.8
37.0
37.2
37.4
37.6
37.8
38.0
INCHEON
TAEAN
LA
TIT
UD
E(N
)
LONGITUDE (E)
125.75 126.00 126.25 126.50
-40
-30
-20
-10
0
DE
PT
H(M
)LONGITUDE (E)
VERTICAL STRUCTURE
Curvilinear Orthogonal Grid
Terrain-Following Vertical Grid(20 arrays)
3-D Sediment Transport Equations
wzyx
s
DSD
ck
Dy
ck
yx
ck
xD
)c)ww(D(
y
)Dvc(
x
)Duc(
t
)Dc(
Variable Description
Falling Velocity
Concentration of Suspended Sediment
Hor/Ver Mixing Coefficients
Source/Sink of Sediment
Source Conc at the Sea Surface
Source Conc. at the Seabed
Deposition Rate through sinking
),,(),(),,( tyxyxHtyxD
c
zyx kkk ,,
wS
sS
sw
bS
dS
dbsw SSSS
ce
cebOb ES
)1(
222bbTbDb vuVC
c
wS sd
1, at
Erosion Rate Porosity
Velocity at seabed RMS Tidal Current
OE
,
wcb
bV T
Source Concentrations of SS in Source Concentrations of SS in Kyunggi BayKyunggi Bay
Dredging Dredging Volume /hrVolume /hr
1,0001,000 mm33/hr/hr 300,000m300,000m33//
12.5 days12.5 days
SS Flux in Over-SS Flux in Over-spilled Waterspilled Water
73.6173.61 kg/skg/s Pumping Water VolumPumping Water Volume : 10 x Loading Volue : 10 x Loading Volumeme
SS Spilled : 10% od LSS Spilled : 10% od Loading Volume (MMS, oading Volume (MMS, 1999)1999)
99%Sand: 99%Sand: Composition of Composition of Spilled SSSpilled SS
0.5:0.25:0.125:0.5:0.25:0.125:
0.0625:0.031250.0625:0.03125
mmmm
3:3:2:1:3:3:2:1:11
7950:7950:7950:7950:
5300:2650:5300:2650:
2650 mg/l2650 mg/l
98%Sand 98%Sand Composition of Composition of Spilled SSSpilled SS
0.5:0.25:0.125:0.5:0.25:0.125:
0.0625:0.031250.0625:0.03125
mmmm
2:2:2:2:2:2:2:2:22
5300:5300:5300:5300:
5300:5300:5300:5300:
5300 mg/l5300 mg/l
Volume =3,000,000 m3 / 12.5day
Ø1:Ø2:Ø3:Ø4:Ø5 = 2:2:2:2:2
SS Dispersion (Started during Spring Tide)SS Dispersion (Started during Spring Tide)
BottomBottom
SurfaceSurface
Volume =3,000,000 m3 / 12.5day
Ø1:Ø2:Ø3:Ø4:Ø5 = 2:2:2:2:2
SS Dispersion (Started During Neap Tide)SS Dispersion (Started During Neap Tide)
BottomBottom
SurfaceSurface
126.22 126.23 126.24 126.2537.09
37.10
37.11
37.12
LA
TIT
UD
E(N
)
LONGITUDE (E)
2001.10.12 16:00
BC
A
505
SURFACE
126.22 126.23 126.24 126.2537.09
37.10
37.11
37.12
LA
TIT
UD
E(N
)
LONGITUDE (E)
2001.10.12 18:00
BC
A5
5
SURFACE
126.22 126.23 126.24 126.2537.09
37.10
37.11
37.12
LA
TIT
UD
E(N
)
LONGITUDE (E)
2001.10.12 20:00
BC
A
5
5
SURFACE
5
126.22 126.23 126.24 126.2537.09
37.10
37.11
37.12
LA
TIT
UD
E(N
)
LONGITUDE (E)
2001.10.12 14:00 ~16:00
A
BC
4.3mg/l
89.0mg/l
: Barge C
9.5mg/l4.6mg/l
16.1mg/l
A
6.9mg/l
CB
: Barge A: Barge B
4.2mg/l
48.3mg/l
7.3mg/l
7.0mg/l
Field Experiment conducted between 14:00 -16:00 on October 12, 2001 in Kyunggi Bay.
Model Validation with Field Observed DataModel Validation with Field Observed Data (2,000 m (2,000 m3 3 3 3 Barges )Barges )
Vertical Profiles of SS Concentration Observed and Simulated for 14:00-16:00 on October12, 2001 in Kyunggi Bay.
Comparison of Model Results and Field Comparison of Model Results and Field Observed DataObserved Data
Tidal current of 0.5 m/s Extractuin Volume 300,000 m3
15 20 25 30 355
10
15
X (km)
Y (km)
SS (mg/l)
BOTTOMTidal Current = 0.5 m/sQ = 300,000 m /12.5daysD + 1
3v
5
1Ø3
+
15 20 25 30 355
10
15
X (km)
Y (km)
SS (mg/l)
BOTTOMTidal Current = 0.5 m/sQ = 300,000 m /12.5daysD + 1
3v
51
1
15
1
Ø4
+
15 20 25 30 355
10
15
X (km)
Y (km)
SS (mg/l)
BOTTOMTidal Current = 0.5 m/sQ = 300,000 m /12.5daysD + 1
3v
1
Ø5
+
15 20 25 30 355
10
15
1 2 3 4 5
X (km)
Y (km)
SS (mg/l)
BOTTOMTidal Current = 0.5 m/sQ = 300,000 m /12.5daysD + 1
3v
∑Ø
+
SS Redistribution at Seabed Based on Particle Size SS Redistribution at Seabed Based on Particle Size (Model Results)(Model Results)
ConclusionsConclusions In this study, a numerical approach using the fully 3-D model ROMS In this study, a numerical approach using the fully 3-D model ROMS
has been conducted to investigate the sediment dynamics arising has been conducted to investigate the sediment dynamics arising from the undersea sand mining operation. Fundamental parameters from the undersea sand mining operation. Fundamental parameters required for model implementation have been obtained through required for model implementation have been obtained through extensive field experiments done in Kyunggi Bay in Korea. extensive field experiments done in Kyunggi Bay in Korea.
The estimation of sediment source concentration adapted in this The estimation of sediment source concentration adapted in this study might be very useful for application to other site-specific area. study might be very useful for application to other site-specific area.
The bottom sediment composition is very important to predict the The bottom sediment composition is very important to predict the habit change at the seabed. Three-dimensional evolution of habit change at the seabed. Three-dimensional evolution of sediment transport shows a variety of dependent parameters on sediment transport shows a variety of dependent parameters on environmental impacts, particularly on the geologic change in environmental impacts, particularly on the geologic change in benthic habitat. benthic habitat.