a)
Water Pollution Control Ordinance (WPCO);
b)
Technical Memorandum for Effluents Discharged into Drainage
and Sewerage Systems, Inland and Coastal Waters (TM- ICW);
c)
Environmental Impact Assessment Ordinance (Cap. 499.
S.16) and the Technical Memorandum on EIA Process (EIAO-TM), Annexes 6 and 14;
and
d)
Practice Note for Professional Persons, Construction
Site Drainage (ProPECC PN1/94).
Water Pollution
Control Ordinance
Table 5.1 Water Quality Objectives Applicable to the
Mirs Bay WCZ
|
Water Quality Objective
|
Applicable Area |
A |
AESTHETIC APPEARANCE |
|
a) |
Waste discharges shall cause no objectionable odours or discolouration of the water. |
Whole zone |
b) |
Tarry residues, floating wood, articles made of glass, plastic, rubber or of any other substances should be absent. |
Whole zone |
c) |
Mineral oil should not be visible on the surface. Surfactants should not give rise to lasting foam. |
Whole zone |
d) |
There should be no recognisable sewage-derived debris |
Whole zone |
e) |
Floating, submerged and semi-submerged objects of a size likely to interfere with the free movement of vessels, or cause damage to vessels, should be absent. |
Whole zone |
f) |
Waste discharges shall not cause the water to contain substances which settle to form objectionable deposits. |
Whole zone |
B |
BACTERIA |
|
a) |
The level of Escherichia coli should not exceed 610 per 100 milligrams per litre, calculated as the geometric mean of all samples collected in one calendar year. |
Secondary Contact Recreation Subzone & Fish Culture Zones |
b) |
The level of Escherichia coli should be zero per 100 ml, calculated as the running median of the most recent 5 consecutive samples taken at intervals of between 7 and 21 days. |
Water Gathering Ground Subzones |
(c) |
The level of Escherichia coli should not exceed 1000 per 100 ml, calculated as the running median of the most recent 5 consecutive samples taken at intervals of between 7 and 21 days. |
Other inland waters of the Zone |
C |
COLOUR |
|
a) |
Waste discharges shall not cause the colour of water to exceed 30 Hazen units. |
Water Gathering Ground Subzones |
b) |
Waste discharges shall not cause the colour of water to exceed 50 Hazen units. |
Other inland waters of the Zone |
D |
DISSOLVED OXYGEN |
|
a) |
Waste discharges shall not cause the level of dissolved oxygen to fall below 4 mg per litre for 90% of the sampling occasions during the year; values should be calculated as water column average. In addition, the concentration of dissolved oxygen should not be less than 2 milligrams per litre within 2 metres of the seabed for 90% of the sampling occasions during the year. |
Marine waters excepting Fish Culture Subzones |
b) |
The dissolved oxygen level should not be less than 5 milligrams per litre for 90% of the sampling occasions during the year; values should be calculated as water column average (arithmetic mean of at least 3 measurements at 1 metre below surface, mid-depth and 1 metre above seabed). In addition, the concentration of dissolved oxygen should not be less than 2 milligrams per litre within 2 metres of the seabed for 90% of the sampling occasions during the year. |
Fish Culture Subzones |
c) |
Waste discharges shall not cause the level of dissolved oxygen to be less than 4 milligrams per litre. |
Inland waters of the Zone |
E |
pH |
|
a) |
The pH of the water should be within the range of 6.5 - 8.5 units. In addition, waste discharges shall not cause the natural pH range to be extended by more than 0.2 units. |
Marine waters |
b) |
Waste discharges shall not cause the pH of the water to exceed the range of 6.5-8.5 units. |
Water Gathering Ground Subzones |
c) |
The pH of the water should be within the range of 6.0 - 9.0 units. |
Other inland waters of the Zone |
F |
TEMPERATURE |
|
|
Waste discharges shall not cause the natural daily temperature range to change by more than 2.0 °C. |
Whole zone |
G |
SALINITY |
|
|
Waste discharges shall not cause the natural ambient salinity level to change by more than 10%. |
Whole zone |
H |
SUSPENDED SOLIDS |
|
a) |
Waste discharges shall neither cause the natural ambient level to be raised by 30% nor give rise to accumulation of suspended solids which may adversely affect aquatic communities. |
Marine waters |
b) |
Waste discharges shall not cause the annual median of suspended solids to exceed 20 milligrams per litre. |
Water Gathering Ground Subzones and Other inland waters of the Zone |
I |
AMMONIA |
|
|
The un-ionized ammoniacal nitrogen level should not be more than 0.021 milligram per litre, calculated as the annual average (arithmetic mean). |
Whole zone |
J |
NUTRIENTS |
|
a) |
Nutrients shall not be present in quantities sufficient to cause excessive or nuisance growth of algae or other aquatic plants. |
Whole zone |
b) |
Without limiting the generality of objective (a) above, the level of inorganic nitrogen should not exceed 0.3 milligram per litre, expressed as annual water column average (arithmetic mean of at least 3 measurements at 1m below surface, mid-depth and 1m above seabed). |
|
K |
5-DAY BIOCHEMICAL OXYGEN DEMAND |
|
a) |
Waste discharges shall not cause the 5-day biochemical oxygen demand to exceed 3 milligrams per litre. |
Water Gathering Ground Subzones |
b) |
Waste discharges shall not cause the 5-day
biochemical oxygen demand to exceed 5 milligrams per litre. |
Other inland waters of the Zone |
L |
CHEMICAL OXYGEN DEMAND |
|
a) |
Waste discharges shall not cause the chemical
oxygen demand to exceed 15 milligrams per litre. |
Water Gathering Ground Subzones |
b) |
Waste discharges shall not cause the chemical
oxygen demand to exceed 30 milligrams per litre. |
Other inland waters of the Zone |
M |
TOXINS |
|
a) |
Waste discharges shall not cause the toxins in water to attain such levels as to produce significant toxic, carcinogenic, mutagenic or teratogenic effects in humans or fish or any other aquatic organisms, with due regard to biologically cumulative effects in food chains and to toxicant interactions with each other. |
Whole zone |
b) |
Waste discharges shall not cause a risk to Whole Zone any beneficial uses of the aquatic environment. |
Whole zone |
Note: (a) Reference: Statement of Water Quality
Objectives (Mirs Bay Water Control Zone) |
Technical Memorandum for Effluents Discharged
into Drainage and Sewerage Systems, Inland and Coastal Waters (TM-ICW)
Environmental Impact Assessment Ordinance (Cap.
499. S.16) and the Technical Memorandum on EIA Process (EIAO-TM), Annexes 6 and
14
Practice Note for
Professional Persons, Construction Site Drainage (ProPECC PN 1/94)
Criterion
for Fish Culture Zones
Overview
Marine Water Quality
Sediment Quality
Table 5.2 Summary of EPD Routine Water Quality Monitoring Data from Selected Stations of the Mirs Bay Water Control Zones in 2005 - 2014
Parameter |
MM1 |
MM2 |
MM3 |
MM7 |
Temperature
(°C) |
23.7 |
23.3 |
22.9 |
23.2 |
(15.2-30.3) |
(14.9-30.0) |
(14.4-29.6) |
(14.5-29.8) |
|
Salinity
(psu) |
31.6 |
32.1 |
32.4 |
32.1 |
(27.1-33.7) |
(28.7-33.6) |
(29.5-33.7) |
(28.8-33.5) |
|
Dissolved
Oxygen (mg/L) - Depth Averaged |
7.0 |
6.7 |
6.5 |
6.6 |
(4.2-12.9) |
(3.7-12.1) |
(2.9-10.3) |
(2.4-12.1) |
|
Dissolved
Oxygen (mg/L) - Bottom |
6.6 |
6.1 |
5.8 |
6.0 |
(1.5-12.7) |
(1.2-11.5) |
(1.3-10.7) |
(0.2-11.6) |
|
Suspended
Solids (mg/L) |
3.9 |
2.5 |
3.9 |
1.9 |
(1.0-10.6) |
(<0.5-16.9) |
(0.7-18.2) |
(0.6-8.4) |
|
5-day
Biochemical Oxygen Demand (mg/L) |
1.3 |
0.9 |
0.7 |
0.9 |
(0.2-4.0) |
(<0.1-2.6) |
(<0.1-3.2) |
(0.2-2.2) |
|
Unionised
Ammonia (mg/L) |
0.003 |
0.002 |
0.002 |
0.002 |
(<0.001-0.019) |
(<0.001-0.008) |
(<0.001-0.005) |
(<0.001-0.009) |
|
Total
Inorganic Nitrogen (mg/L) |
0.1 |
0.1 |
0.1 |
0.1 |
(0.0-0.4) |
(0.0-0.2) |
(0.0-0.2) |
(0.0-0.2) |
|
Orthophosphate
Phosphorus (mg/L) |
0.008 |
0.007 |
0.007 |
0.007 |
(<0.002-0.024) |
(<0.002-0.023) |
(<0.002-0.022) |
(<0.002-0.027) |
|
Total
Phosphorus (mg/L) |
0.03 |
0.02 |
0.02 |
0.02 |
(<0.02-0.06) |
(<0.02-0.04) |
(<0.02-0.05) |
(<0.02-0.05) |
|
Chlorophyll-a
(mg/L) |
7.2 |
4.0 |
2.7 |
3.6 |
(0.5-30.0) |
(0.4-20.6) |
(0.4-14.3) |
(0.6-14.4) |
|
Escherichia
coli
(cfu/100ml) |
31 |
2 |
2 |
1 |
(<1-7683) |
(<1-424) |
(<1-174) |
(<1-161) |
Notes:
(a)
Data presented are depth-averaged values calculated by taking
the means of three depths, i.e. surface (S), mid-depth (M) and bottom (B),
except as specified.
(b)
Data presented are annual arithmetic means except for E. coli, which are geometric means. Data enclosed in brackets
indicate the ranges of the corresponding depths.
(c)
With the exception E.coli, data below the corresponding reporting
limits (RL) are calculated as 0.5×RL. For E.coli,
data below the corresponding RL are calculated as 1.
(d)
WQOs for TIN in Mirs Bay = 0.3 mg/L.
Table 5.3 Summary of EPD Routine Marine Sediment Quality Monitoring Data from Selected Station of for the Mirs Bay Water Control Zone (2010-2014)
Parameter |
ETWB TC(W) No. 34/2002
Guideline |
Starling Inlet |
Crooked Island |
Mirs Bay (North) |
||
LCEL |
UCEL |
MS1 |
MS2 |
MS7 |
MS3 |
|
Arsenic
(mg/kg) |
12 |
42 |
8.3 |
7.3 |
6.7 |
5.7 |
|
|
(7.1-9.5) |
(6.0-8.6) |
(5.8-7.8) |
(3.8-7.3) |
|
Cadmium
(mg/kg) |
1.5 |
4 |
0.2 |
0.3 |
0.3 |
<0.1 |
|
|
(0.1-0.3) |
(0.1-0.4) |
(<0.1-0.5) |
(<0.1-<0.1) |
|
Chromium
(mg/kg) |
80 |
160 |
27 |
33 |
33 |
26 |
|
|
(19-32) |
(27-37) |
(27-38) |
(21-35) |
|
Copper
(mg/kg) |
65 |
110 |
24 |
21 |
20 |
11 |
|
|
(17-32) |
(19-24) |
(13-26) |
(7-17) |
|
Lead
(mg/kg) |
75 |
110 |
45 |
45 |
41 |
29 |
|
|
(34-54) |
(34-50) |
(27-47) |
(20-42) |
|
Mercury
(mg/kg) |
0.5 |
1 |
0.06 |
0.06 |
0.07 |
<0.05 |
|
|
(<0.05-0.07) |
(<0.05-0.07) |
(0.05-0.10) |
(<0.05-<0.05) |
|
Nickel
(mg/kg) |
40 |
40 |
17 |
22 |
23 |
18 |
|
|
(12-20) |
(18-25) |
(18-25) |
(13-23) |
|
Silver
(mg/kg) |
1 |
2 |
0.6 |
0.3 |
0.2 |
<0.2 |
|
|
(0.3-1.1) |
(0.2-0.4) |
(<0.2-0.3) |
(<0.2-<0.2) |
|
Zinc
(mg/kg) |
200 |
270 |
94 |
100 |
96 |
67 |
|
|
(69-110) |
(87-110) |
(82-110) |
(52-89) |
|
Total
Polychlorinated Biphenyls (PCBs) (mg / kg) |
23 |
180 |
18 |
18 |
18 |
18 |
|
|
(18-18) |
(18-18) |
(18-18) |
(18-18) |
|
Low
Molecular Weight Polycyclic Aromatic Hydrocarbons (PAHs) (μg/kg) |
550 |
3,160 |
110 |
120 |
130 |
100 |
|
|
(90-200) |
(90-210) |
(90-220) |
(90-130) |
|
High
Molecular Weight Polycyclic Aromatic Hydrocarbons (PAHs) (μg/kg) |
1,700 |
9,600 |
48 |
52 |
77 |
31 |
|
|
(29-90) |
(32-81) |
(31-170) |
(18-65) |
|
Chemical
Oxygen Demand (mg/kg) |
-- |
-- |
14100 |
14500 |
15700 |
12000 |
|
|
(11000-17000) |
(11000-18000) |
(13000-21000) |
(9900-14000) |
|
Total Kjeldahl Nitrogen (mg/kg) |
-- |
-- |
530 |
610 |
670 |
500 |
|
|
(350-620) |
(460-770) |
(530-800) |
(250-610) |
|
Ammonia
Nitrogen (mg/kg) |
-- |
-- |
5.85 |
6.96 |
9.94 |
8.09 |
|
|
(0.13-10.00) |
(0.07-14.00) |
(7.30-13.00) |
(1.40-25.00) |
|
Total
Phosphorus (mg/kg) |
-- |
-- |
180 |
180 |
190 |
180 |
|
|
(140-200) |
(150-210) |
(170-210) |
(100-220) |
Table 5.4 Summary of Marine Sediment Quality at Geophysical Survey Stations conducted under this Study
Parameters |
Ag |
As |
Cd |
Cr |
Cu |
Ni |
Pb |
Zn |
Hg |
Total PCB |
Low M.W. PAHs |
High M.W. PAHs |
TBT |
Classification |
Unit |
mg/kg |
mg/kg |
mg/kg |
mg/kg |
mg/kg |
mg/kg |
mg/kg |
mg/kg |
mg/kg |
µg/kg |
µg/kg |
µg/kg |
µg TBT/L |
|
Reporting
Limits |
0.1 |
1 |
0.2 |
1 |
1 |
1 |
1 |
1 |
0.05 |
18 |
550 |
1700 |
0.015 |
|
(LCEL) |
1 |
12 |
1.5 |
80 |
65 |
40 |
75 |
200 |
0.5 |
23 |
550 |
1700 |
0.15 |
|
(UCEL) |
2 |
42 |
4 |
160 |
110 |
40 |
110 |
270 |
1 |
180 |
3160 |
9600 |
0.15 |
|
10
×
(LCEL) |
10 |
120 |
15 |
800 |
650 |
400 |
750 |
2000 |
5 |
230 |
5500 |
17000 |
1.5 |
|
GB1 |
0.8 |
8 |
0.2 |
36 |
38 |
22 |
49 |
154 |
0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
GB2 |
1 |
8 |
0.3 |
39 |
41 |
24 |
55 |
164 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
GB3 |
0.9 |
10 |
0.3 |
38 |
37 |
24 |
54 |
157 |
0.06 |
<18 |
<550 |
<1700 |
<0.015 |
L |
GB4 |
0.9 |
8 |
0.2 |
37 |
39 |
23 |
54 |
167 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
GB5 |
0.9 |
9 |
0.3 |
39 |
40 |
23 |
53 |
167 |
0.07 |
<18 |
<550 |
<1700 |
<0.015 |
L |
GB6 |
0.4 |
3 |
<0.2 |
11 |
18 |
5 |
16 |
64 |
<0.05 |
<18 |
<550 |
<1700 |
-- |
L |
GB7 |
0.3 |
3 |
<0.2 |
8 |
13 |
4 |
12 |
47 |
<0.05 |
<18 |
<550 |
<1700 |
-- |
L |
GB8 |
0.7 |
14 |
0.2 |
17 |
38 |
10 |
47 |
134 |
0.07 |
<18 |
<550 |
<1700 |
<0.015 |
M |
SD1 0M-0.9M |
0.2 |
11 |
<0.2 |
28 |
21 |
16 |
49 |
102 |
0.08 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD1 0.9M-1.9M |
0.1 |
8 |
<0.2 |
29 |
10 |
18 |
36 |
92 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD1 1.9M-2.9M |
0.1 |
8 |
<0.2 |
23 |
8 |
14 |
30 |
69 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD1 2.9M-3.9M |
0.1 |
16 |
<0.2 |
23 |
10 |
16 |
26 |
63 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
M |
SD2 0M-0.9M |
0.8 |
9 |
0.3 |
42 |
39 |
23 |
62 |
166 |
0.06 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD2 0.9M-1.9M |
0.1 |
12 |
<0.2 |
27 |
12 |
16 |
43 |
89 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD2 1.9M-2.9M |
0.1 |
6 |
<0.2 |
33 |
9 |
20 |
35 |
90 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD2 2.9M-3.9M |
0.1 |
6 |
<0.2 |
31 |
10 |
18 |
37 |
86 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD2 5.9M-6.9M |
<0.1 |
16 |
<0.2 |
6 |
5 |
3 |
16 |
23 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
M |
SD3 0M-0.9M |
0.2 |
12 |
<0.2 |
27 |
15 |
16 |
53 |
97 |
0.10 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD3 0.9M-1.9M |
0.1 |
7 |
<0.2 |
29 |
9 |
17 |
33 |
90 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD3 1.9M-2.9M |
0.1 |
10 |
<0.2 |
28 |
8 |
16 |
34 |
86 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD3 2.9M-3.9M |
0.1 |
7 |
<0.2 |
33 |
10 |
19 |
36 |
99 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD3 5.9M-6.9M |
0.2 |
12 |
<0.2 |
25 |
13 |
16 |
43 |
80 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD3 8.9M-9.9M |
0.2 |
12 |
<0.2 |
30 |
12 |
20 |
37 |
75 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD4 0M-0.9M |
0.1 |
10 |
<0.2 |
26 |
10 |
15 |
39 |
77 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD4 0.9M-1.9M |
0.1 |
10 |
<0.2 |
31 |
11 |
16 |
39 |
88 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD4 1.9M-2.9M |
0.1 |
11 |
<0.2 |
35 |
10 |
20 |
36 |
98 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD4 2.9M-3.9M |
0.1 |
9 |
<0.2 |
28 |
12 |
17 |
44 |
85 |
<0.05 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD5 0M-0.9M |
0.2 |
10 |
<0.2 |
27 |
13 |
15 |
46 |
95 |
0.08 |
<18 |
<550 |
<1700 |
<0.015 |
L |
SD5 0.9M-1.9M |
<0.1 |
7 |
<0.2 |
24 |
8 |
15 |
31 |
75 |
<0.05 |
<18 |
<550 |
<1700 |
-- |
L |
SD5 1.9M-2.9M |
0.1 |
9 |
<0.2 |
30 |
10 |
18 |
37 |
84 |
<0.05 |
<18 |
<550 |
<1700 |
-- |
L |
SD5 2.9M-3.9M |
0.2 |
10 |
<0.2 |
23 |
12 |
14 |
46 |
80 |
<0.05 |
<18 |
<550 |
<1700 |
-- |
L |
Notes:
LCEL:
Lower Chemical Exceedance Level
UCEL:
Upper Chemical Exceedance Level
PCB:
Polychlorinated Biphenyl
Low
/ High M.W. PAHs: Low / High Molecular Weight Polycyclic Aromatic Hydrocarbons
TBT:
Tributyltin
Table 5.5 Summary of Sediment Elutriate Test Results at Geophysical Survey Stations conducted under this Study
Parameter
(Unit) |
WQC |
LOR |
SD3 |
SD3 |
SD3 |
SD3 |
SD3 |
SD3 |
SD3 |
SD5 |
SD5 |
SD5 |
SD5 |
SD5 |
GB1 |
GB2 |
GB4 |
GB5 |
GB1 |
GB2 |
GB4 |
GB5 |
0M-0.9M |
0.9M-1.9M |
1.9M-2.9M |
2.9M-3.9M |
5.9M-6.9M |
8.9M-9.9M |
Water Blank |
0M-0.9M |
0.9M-1.9M |
1.9M-2.9M |
2.9M-3.9M |
Water Blank |
Water
Blank |
Water
Blank |
Water
Blank |
Water
Blank |
|||||||
Mercury (µg/L) |
0.3 |
0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
<0.5 |
Arsenic (µg/L) |
25 |
10 |
20 |
<10 |
<10 |
<10 |
<10 |
<10 |
<10 |
30 |
20 |
<10 |
20 |
<10 |
<10 |
<10 |
<10 |
10 |
<10 |
<10 |
<10 |
<10 |
Cadmium (µg/L) |
2.5 |
0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
<0.2 |
Chromium (µg/L) |
15 |
1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
Copper (µg/L) |
5 |
1 |
<1 |
<1 |
1 |
<1 |
1 |
1 |
2 |
1 |
1 |
2 |
2 |
2 |
1 |
<1 |
1 |
1 |
2 |
2 |
2 |
2 |
Lead (µg/L) |
25 |
1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
Nickel (µg/L) |
30 |
1 |
<1 |
1 |
<1 |
<1 |
1 |
1 |
1 |
1 |
<1 |
<1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
<1 |
<1 |
Silver (µg/L) |
1.9 |
1 |
1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
Zinc (µg/L) |
40 |
10 |
<10 |
<10 |
<10 |
22 |
<10 |
<10 |
13 |
<10 |
<10 |
<10 |
<10 |
16 |
<10 |
<10 |
<10 |
<10 |
<10 |
<10 |
<10 |
<10 |
Total PCBs (µg/L) |
0.03 |
0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
<0.18 |
Total PAHs (µg/L) |
3 |
9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
<9 |
TBT (µg/L) |
0.1 |
0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
<0.015 |
Ammonia (mg/L) |
- |
0.01 |
0.89 |
0.47 |
0.51 |
0.52 |
0.71 |
0.31 |
0.02 |
0.96 |
0.58 |
0.47 |
0.45 |
0.04 |
0.64 |
0.65 |
0.72 |
1.15 |
0.02 |
0.02 |
0.03 |
<0.01 |
Reactive
Phosphorous (µg/L) |
- |
10 |
170 |
150 |
110 |
100 |
40 |
40 |
<10 |
220 |
200 |
140 |
140 |
<10 |
20 |
20 |
20 |
20 |
<10 |
<10 |
<10 |
<10 |
Total Kjeldahl Nitrogen
(mg/L) |
- |
0.1 |
1.3 |
1.1 |
0.9 |
1 |
1.5 |
0.7 |
0.3 |
1.4 |
1.0 |
0.9 |
1.0 |
0.3 |
1.1 |
1.1 |
1.3 |
3.4 |
0.3 |
0.3 |
0.3 |
0.2 |
Total Phosphorous
(mg/L) |
- |
0.1 |
0.2 |
0.18 |
0.15 |
0.1 |
0.07 |
0.08 |
<0.01 |
0.25 |
0.22 |
0.16 |
0.19 |
<0.01 |
0.06 |
0.05 |
0.05 |
0.09 |
<0.01 |
<0.01 |
0.01 |
<0.01 |
Nitrate (mg/L) |
- |
0.01 |
0.04 |
0.01 |
<0.01 |
<0.01 |
0.01 |
0.03 |
<0.01 |
0.07 |
0.05 |
<0.01 |
0.06 |
<0.01 |
<0.01 |
<0.01 |
<0.01 |
<0.01 |
<0.01 |
<0.01 |
<0.01 |
<0.01 |
Nitrite (mg/L) |
- |
0.01 |
0.07 |
0.05 |
0.08 |
0.1 |
0.06 |
0.07 |
0.05 |
0.06 |
0.09 |
0.14 |
0.09 |
0.09 |
0.04 |
0.05 |
0.07 |
0.06 |
0.05 |
0.06 |
0.09 |
0.07 |
Notes:
(a)
WQC: Water quality assessment criteria (stipulated under Section 5.5.11);
LOR: Limit of Reporting
(b)
Contaminant concentration values above the corresponding WQC
are underlined, including those with LOR > WQC.
Table 5.6 Water Quality Sensitive Receivers
(WSRs) in the Vicinity of the Project Site
Description |
Location |
Model Output Location |
Fisheries Sensitive Receivers |
|
|
Fish
Culture Zones |
Sha
Tau Kok Ap Chau Kat O O Pui Tong Sai Lau Kong Wong Wan Temporary Relocation Zone of Fish Rafts for the
Sha Tau Kok Fish Culture Zone 1 and 2 |
FCZ1 FCZ2 FCZ3 FCZ4 FCZ5 FCZ6 FCZ7, FCZ8 |
Spawning
and Nursery Grounds of Commercial Fisheries Resources |
North Mirs Bay |
FCZ2-FCZ6,
M8-M14, MP1, MP2 * |
Ecological Sensitive Receivers |
|
|
Seagrass
bed |
- |
SG |
Horseshoe crab |
Off STKSTW |
H1 |
|
Off Pak Hok Lam |
H2 |
|
Off Nga Yiu Tau |
H3 |
|
A Chau |
H4 |
|
Off Luk Keng |
H5 |
Mangrove stand |
Off Nga Yiu Tau |
M1 |
|
Off Wu Shek Kok |
M2 |
|
Off Tai Wan |
M3 |
|
Off Luk Keng |
M4 |
|
Off Kuk Po |
M5 |
|
Kei Shan Tsui |
M6 |
|
Tai Sham Chung |
M7 |
|
So Lo Pun |
M8 |
|
Pak Kok Wan |
M9 |
|
Yan Chau Tong Marine Park |
M10, M11, M13, M14 |
|
Ngau Shi Wu Wan |
M12 |
Marine Park |
Yan Chau Tong |
MP1, MP2 |
Coral
sites identified under this EIA |
Off
Ah Kung Au |
T1,
T2, T3 |
EPD Water Quality Monitoring Station |
||
Water Quality Monitoring Station |
Mirs Bay Water Control Zone (WCZ) |
MM1, MM2, MM3, MM7 |
*Note: The spawning and nursery grounds of commercial
fisheries resources covers a wide range in the Study Area and included about
half of the model output locations identified under this Study. The model output location FCZ2 which is
closest to the proposed and existing outfall would be adopted to represent
the worst case impact to this WSR. |
Suspended Solids
Sediment Deposition Rate and
Suspended Solids Criteria for Corals
Dissolved Oxygen
Table 5.7 Water Quality Assessment Criteria for Suspended Solids (mg/L) at WSRs
Sensitive Receivers |
Name |
WSR ID |
EPD Station |
Depth |
Wet
Season |
Dry
Season |
||
Ambient Level (a) |
WQO Allowable Change |
Ambient Level (a) |
WQO Allowable Change |
|||||
Fisheries Sensitive Receivers |
||||||||
Fish
Culture Zones |
Sha Tau Kok |
FCZ1 |
MM1 |
Depth-averaged |
6.12 |
1.84 |
6.67 |
2.00 |
|
Ap Chau |
FCZ2 |
MM1 |
Depth-averaged |
6.12 |
1.84 |
6.67 |
2.00 |
|
Kat O |
FCZ3 |
MM2 |
Depth-averaged |
3.25 |
0.98 |
3.91 |
1.17 |
|
O Pui Tong |
FCZ4 |
MM2 |
Depth-averaged |
3.25 |
0.98 |
3.91 |
1.17 |
|
Sai Lau Kong |
FCZ5 |
MM7 |
Depth-averaged |
2.64 |
0.79 |
3.57 |
1.07 |
|
Wong Wan |
FCZ6 |
MM7 |
Depth-averaged |
2.64 |
0.79 |
3.57 |
1.07 |
|
Temporary Relocation Zone of Fish Rafts
for the STKFCZ |
FCZ7,FCZ8 |
MM1 |
Depth-averaged |
6.12 |
1.84 |
6.67 |
2.00 |
Spawning and Nursery Grounds of Commercial
Fisheries Resources |
North Mirs Bay |
FCZ2 |
MM1 |
Depth-averaged |
6.12 |
1.84 |
6.67 |
2.00 |
Ecological Sensitive Receivers |
||||||||
Seagrass
bed |
Seagrass
bed |
SG |
MM1 |
Depth-averaged |
6.12 |
1.84 |
6.67 |
2.00 |
Mangrove
stand |
Off
Nga Yiu Tau |
M1 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
|
Off
Wu Shek Kok |
M2 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
|
Off
Tai Wan |
M3 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
|
Off
Luk Keng |
M4 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
|
Off
Kuk Po |
M5 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
|
Kei
Shan Tsui |
M6 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
|
Tai
Sham Chung |
M7 |
MM2 |
Depth-averaged |
3.25 |
- |
3.91 |
- |
|
So
Lo Pun |
M8 |
MM2 |
Depth-averaged |
3.25 |
- |
3.91 |
- |
|
Pak
Kok Wan |
M9 |
MM2 |
Depth-averaged |
3.25 |
- |
3.91 |
- |
|
Yan
Chau Tong Marine Park |
M10 |
MM2 |
Depth-averaged |
3.25 |
- |
3.91 |
- |
|
Yan
Chau Tong Marine Park |
M11 |
MM2 |
Depth-averaged |
3.25 |
- |
3.91 |
- |
|
Yan
Chau Tong Marine Park |
M12 |
MM7 |
Depth-averaged |
2.64 |
- |
3.57 |
- |
|
Yan
Chau Tong Marine Park |
M13 |
MM7 |
Depth-averaged |
2.64 |
- |
3.57 |
- |
|
Ngau
Shi Wu Wan |
M14 |
MM7 |
Depth-averaged |
2.64 |
- |
3.57 |
- |
Horseshoe
crab |
Off
STKSTW |
H1 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
|
Off
Nga Yiu Tau |
H2 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
|
Off
Pak Hok Lam |
H3 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
|
A
Chau |
H4 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
|
Off
Luk Keng |
H5 |
MM1 |
Depth-averaged |
6.12 |
- |
6.67 |
- |
Marine
Park |
Yan
Chau Tong |
MP1,
MP2 |
MM7 |
Depth-averaged |
2.64 |
0.79 |
3.57 |
1.07 |
Coral sites identified under this EIA |
Off Ah Kung Au |
T1, T2, T3 |
MM1 |
Bottom |
8.22 |
2.47 |
8.99 |
2.70 |
Notes:
(a)
Ambient level is calculated as 90th percentile of
the EPD routine monitoring data of 2005-2014 at respective EPD station
close to the WSRs;
(b)
This table is applicable for those WSRs which were assessed
against the WQO. No assessment criterion
is recommended for mangrove and horseshoe crab WSR.
Table 5.8 Water Quality Assessment Criteria for Dissolved Oxygen (mg/L) at WSRs
Sensitive Receivers |
Name |
WSR ID |
EPD Station |
Depth |
Wet
Season |
Dry
Season |
Annual |
|||
Ambient Level (a) |
WQO Allowable DO
Depletion |
Ambient Level (a) |
WQO Allowable DO
Depletion |
Ambient Level (a) |
WQO Allowable DO Depletion |
|||||
Fisheries Sensitive Receivers |
|
|
|
|
|
|
||||
Fish
Culture Zones |
Sha Tau Kok |
FCZ1 |
MM1 |
Depth-averaged |
4.56 |
- |
6.23 |
1.23 |
5.06 |
0.06 |
|
Ap Chau |
FCZ2 |
MM1 |
Depth-averaged |
4.56 |
- |
6.23 |
1.23 |
5.06 |
0.06 |
|
Kat O |
FCZ3 |
MM2 |
Depth-averaged |
4.66 |
- |
6.72 |
1.72 |
4.92 |
- |
|
O Pui Tong |
FCZ4 |
MM2 |
Depth-averaged |
4.66 |
- |
6.72 |
1.72 |
4.92 |
- |
|
Sai Lau Kong |
FCZ5 |
MM7 |
Depth-averaged |
4.22 |
- |
6.62 |
1.62 |
4.48 |
- |
|
Wong Wan |
FCZ6 |
MM7 |
Depth-averaged |
4.22 |
- |
6.62 |
1.62 |
4.48 |
- |
|
Temporary Relocation Zone of Fish Rafts
for the STKFCZ |
FCZ7,FCZ8 |
MM1 |
Depth-averaged |
4.56 |
- |
6.23 |
1.23 |
5.06 |
0.06 |
Spawning and Nursery Grounds of Commercial
Fisheries Resources |
North Mirs Bay |
FCZ2 |
MM1 |
Depth-averaged |
4.56 |
- |
6.23 |
1.23 |
5.06 |
0.06 |
Ecological Sensitive Receivers |
|
|
|
|
|
|
||||
Seagrass
bed |
Seagrass
bed |
SG |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
Mangrove
stand |
Off
STKSTW |
M1 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
|
Off
Wu Shek Kok |
M2 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
|
Off
Tai Wan |
M3 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
|
Off
Luk Keng |
M4 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
|
Off
Kuk Po |
M5 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
|
Kei
Shan Tsui |
M6 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
|
Tai
Sham Chung |
M7 |
MM2 |
Depth-averaged |
4.66 |
0.66 |
6.72 |
2.72 |
4.92 |
0.92 |
|
So
Lo Pun |
M8 |
MM2 |
Depth-averaged |
4.66 |
0.66 |
6.72 |
2.72 |
4.92 |
0.92 |
|
Pak
Kok Wan |
M9 |
MM2 |
Depth-averaged |
4.66 |
0.66 |
6.72 |
2.72 |
4.92 |
0.92 |
|
Yan
Chau Tong Marine Park |
M10 |
MM2 |
Depth-averaged |
4.66 |
0.66 |
6.72 |
2.72 |
4.92 |
0.92 |
|
Yan
Chau Tong Marine Park |
M11 |
MM2 |
Depth-averaged |
4.66 |
0.66 |
6.72 |
2.72 |
4.92 |
0.92 |
|
Yan
Chau Tong Marine Park |
M12 |
MM7 |
Depth-averaged |
4.22 |
0.22 |
6.62 |
2.62 |
4.48 |
0.48 |
|
Yan
Chau Tong Marine Park |
M13 |
MM7 |
Depth-averaged |
4.22 |
0.22 |
6.62 |
2.62 |
4.48 |
0.48 |
|
Ngau
Shi Wu Wan |
M14 |
MM7 |
Depth-averaged |
4.22 |
0.22 |
6.62 |
2.62 |
4.48 |
0.48 |
Horseshoe
crab |
Off
Muk Min Tau |
H1 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
|
Off
Nga Yiu Tau |
H2 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
|
Off
Pak Hok Lam |
H3 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
|
A
Chau |
H4 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
|
Off
Luk Keng |
H5 |
MM1 |
Depth-averaged |
4.56 |
0.56 |
6.23 |
2.23 |
5.06 |
1.06 |
Marine
Park |
Yan
Chau Tong |
MP1,
MP2 |
MM7 |
Depth-averaged |
4.22 |
0.22 |
6.62 |
2.62 |
4.48 |
0.48 |
Coral sites identified under this EIA |
Off Ah Kung Au |
T1, T2, T3 |
MM1 |
Bottom |
4.20 |
2.20 |
6.20 |
4.20 |
4.50 |
2.50 |
Notes:
(a)
Ambient level is calculated as 10th-percentile of
the EPD routine monitoring data of 2005 to 2014 at respective EPD station
close to WSRs
(b)
The 10th-percentile DO levels from 2005
– 2014 are all
below 5 mg/L at all selected EPD monitoring stations in wet season. The potential DO depletion at FCZs would be
considered based on annual 10th-percentile DO level. Further elaboration would be provided in the
construction phase impact assessment in section
5.8.
(c)
Reference has been made to EIAO
Guidance Note No. 7/2010 (section 4.2) regarding dry (November to March) and
wet season (April to October).
Criteria for
Nutrients & Bacteria
Criteria for Fish
Culture Zones
Criteria for
Dissolved Metals and Organic Compounds
Table 5.9 Summary
of Assessment Criteria for Dissolved Metals and Organic Compounds
Parameter |
Unit |
Assessment Criteria for this Study |
Metals |
|
|
Cadmium (Cd) |
mg/L |
2.5 (a) (b) |
Chromium (Cr) |
mg/L |
15
(a) (b) |
Copper (Cu) |
mg/L |
5 (a) (b) |
Nickel (Ni) |
mg/L |
30 (a) (b) |
Lead (Pb) |
mg/L |
25 (a) (b) |
Zinc (Zn) |
mg/L |
40 (a) (c) |
Mercury (Hg) |
mg/L |
0.3 (b) |
Arsenic (As) |
mg/L |
25 (a) (b) |
Silver (Ag) |
mg/L |
1.9 (d) |
Total PAHs |
mg/L |
3.0 (f) |
PCBs |
|
|
Total PCBs |
mg/L |
0.03 (d) |
Organotins |
|
|
Tributyltin (TBT) |
mg/L |
0.1 (e) |
Notes:
(a) UK Environment Agency, Environmental Quality Standards (EQS) for List 1 & 2 dangerous substances, EC Dangerous Substances Directive (76/464/EEC) (http://www.ukmarinesac.org.uk/activities/water-quality/wq4_1.htm).
(b) Annual average dissolved concentration (i.e. usually involving filtration a 0.45-um membrane filter before analysis).
(c) Annual average total concentration (i.e. without filtration).
(d) U.S. Environmental Protection Agency, National Recommended Water Quality Criteria, 2009. (http://www.epa.gov/waterscience/criteria/wqctable). The Criteria Maximum Concentration (CMC) is an estimate of the highest concentration of a material in surface water (i.e. saltwater) to which an aquatic community can be exposed briefly without resulting in an unacceptable effect. CMC is used as the criterion of the respective compounds in this study.
(e) Salazar MH, Salazar SM (1996) Mussels as Bioindicators: Effects of TBT on Survival, Bioaccumulation, and Growth under Natural Conditions. In Organotin, edited by M.A. Champ and P.F. Seligman. Chapman & Hall, London.
(f) Australian and New Zealand Environment and Conservation Council (ANZECC), Australian and New Zealand Guidelines for Fresh and Marine Water Quality (1992)
Standard
for Reuse of Treated Effluent
Table 5.10 Proposed Reclaimed Water Quality for non-potable uses within STKSTW
Determinand |
Unit |
Proposed Reclaimed Water
Quality Criteria for STKSTW * |
pH |
n/a |
6-9 (d) |
Turbidity |
NTU |
≤ 2 (b-d) |
Total
Suspended Solids |
mg/L |
≤ 10 (a) |
Biochemical
Oxygen Demand (BOD5) |
mg/L |
≤10 (a) |
Colour |
Hazen
Unit |
≤ 20 (a) |
Ammonia
Nitrogen |
mg/L |
≤ 1 (a) |
Threshold Odour Number |
T.O.N |
≤ 100 (a) |
Synthetic
Detergents |
mg/L |
≤ 5 (a) |
Escherichia coli |
cfu/100ml |
Not Detectable (b-d) |
Dissolved
Oxygen |
mg/L |
≥ 2 (a) |
Residual
Chlorine |
mg/L |
≥ 1 (b)(e) (For cleansing and toilet flushing) |
|
mg/L |
≤ 1 (d) (For landscape
irrigation) |
*Note: The effluent standards are adopted from: (a)
Agreement. No. CE 29/2001 – Outlying
Islands Sewerage Stage 1 Phase 1 – Ngong Ping Sewage Treatment Works and Sewerage
Investigation, Design and Construction. (b)
Agreement No. CE 16/2004
(DS) – Demonstration Scheme on Reclaimed Water Uses in the North District –
Investigation (c)
Contract No. SS P320 –
Design and Construction of the Redevelopment of Lo Wu Correctional Institution (d)
Guideline for Water Reuse,
(2004), USEPA |
General Methodology
Dissolved Oxygen Depletion
Nutrients
Heavy Metals and Micro-Organic Pollutants
Effluent
Discharge from Temporary Sewage Treatment Plant
Operation Phase
Modelling Scenarios
Table 5.11 Modelling Scenarios for Delft3d Water Quality Modelling Scenarios
Scenarios |
Simulation Year |
Simulated Flow from STKSTW (m3/day) |
Description |
Far field water
quality - baseline |
2011 |
1,660 at existing outfall |
Baseline scenario of 2011 at actual flow rate and actual effluent concentration of the existing STKSTW for model verification |
Far field water
quality - baseline |
2030 |
1,660 at existing outfall |
Baseline scenario of
2030 at maximum ADWF of the existing STKSTW for project operation |
Far field water
quality - operation |
2030 |
10,000 at new submarine outfall |
Operation scenario
of 2030 at maximum ADWF of the expanded STKSTW |
Compilation of
Background Loading
Sewage Effluent from
STKSTW
Table 5.12 Flow and Load of Effluent Discharged from
the STKSTW in Modelled Scenarios
Parameters |
Unit |
Baseline |
Operation |
Flow |
m3/s |
0.0192 |
0.1157 |
BOD5 |
mg/L |
10/20/40 |
10/20/40 |
SS |
mg/L |
15/30/60 |
15/30/60 |
TN |
mg/L |
22/43/86 |
6/12/24 |
Total Phosphate |
mg/L |
4/5/10 |
3/4/8 |
E. Coli |
count/100mL |
100/1500 |
100/1500 |
Note: For all parameters except E.coli, the first, second and third numbers indicate the mean, 95th percentile and maximum concentration respectively. For E.coli, the first number indicates the monthly geometric mean value while the second number indicates the 95%ile concentration.
Uncertainties in
Assessment Methodology
Uncertainties in Sediment Transport Assessment
·
The calculations of loss rates of sediment to
suspension are based on conservative estimates for the methods of working;
·
The assessment is based on peak rate for sheetpile
installation and removal for cofferdam construction. In reality these will only occur for a short
period of time
Uncertainties arising
from Operations
·
Potential change in effluent discharge on the Mainland side of the Mirs
Bay; and
·
Potential change in capacity of mariculture activities in Starling Inlet
and the rest of the Mirs Bay.
·
Wastage and leaching of fish feed;
·
Excretion and faecal production from fish; and
·
Disposal of dead fish
Limitation in Near Field Models
Construction Phases
·
Changes in water quality, including suspended
sediment dispersion, sediment deposition, DO depletion, and elevated
concentrations of nutrients, heavy metals and micro-organic pollutants, due to
marine construction at submarine outfall;
·
Decommissioning of existing submarine outfall;
·
Vessel discharges;
·
Land-based site runoff from construction workforce;
and
·
Spillage of chemicals.
Operation Phase
Construction Phases
Pane 5.1 Tentative
Programme for Project Construction and Operation
Note: The pane shows an overlapping period of
the TSTP and the expanded STKSTW during the initial commissioning of the
expanded STKSTW. Please note that the
TSTP and the expanded STKSW would not operate concurrently. TSTP would use the
existing outfall while the expanded STKSTW would use the proposed outfall. There
is no incident when discharge from both outfalls occurs at the same time.
Elevation
of Suspended Solids and Sedimentation
Schematics
(Side View and Plan View) for Cofferdam Construction at Proposed Submarine
Outfall
t
·
Shatin to Central Link - Hung Hom to Admiralty
Section (AEIAR-166/2012). EP granted in Feb 2012 (EP-064/2000).
·
ShaTin to Central Link Protection Works at Causeway
Bay Typhoon Shelter (AEIAR-159/2011). EP granted in Feb 2011 (EP-416/2011).
·
Wan Chai Development Phase II and Central-Wan Chai
Bypass (AEIAR-125/2008). EP granted in Dec 2008 (EP-356/2009).
·
Liquefied Natural Gas (LNG) Receiving Terminal and
Associated Facilities (AEIAR-106/2007). EP granted on 3 April 2007
(EP-257/2007).
·
The Proposed Submarine Gas Pipelines from Cheng Tou
Jiao Liquefied Natural Gas Receiving Terminal, Shenzhen to Tai Po Gas
Production Plant, Hong Kong – EIA Study (AEIAR-071/2003). EP granted on 23
April 2003 (EP-167/2003).
·
132kV Submarine Cable Installation for Wong Chuk
Hang - Chung Hom Kok 132kV Circuits (AEP-126/2002). EP granted on 2 April 2002
(EP-126/2002).
·
FLAG North Asian Loop (AEP-099/2001). EP granted on
18 June 2001 (EP-099/2001).
·
East Asian Crossing (EAC) Cable System (TKO), Asia
Global Crossing (AEP-081/2000). EP granted on 4 October 2000 (EP-081/2000).
·
East Asian Crossing (EAC) Cable System, Asia Global
Crossing(AEP-079/2000). EP granted on 6 September 2000 (EP-079/2000).
·
Submarine Cable Landing Installation in Tong Fuk
Lantau for Asia Pacific Cable Network 2 (APCN 2) Fibre Optic Submarine Cable
System, EGS. EP granted on 26 July 2000 (EP-069/2000).
·
Telecommunication Installation at Lot 591SA in DD
328, Tong Fuk, South Lantau Coast and the Associated Cable Landing Work in Tong
Fuk, South Lantau for the North Asia Cable (NAC) Fibre Optic Submarine Cable
System (AEP-064/2000). EP granted in June 2000 (EP-064/2000).
Pane 5.3 Location and
Extent of Sediment Released by the Movement of Sheetpiles
|
Note:
The above schematic is prepared to illustrate the location and extent of
sediment that is expected to be disturbed by the movement of sheetpiles. It is not prepared in scale and certain
engineering details may not be presented.
Loss
Rate (kg/s)
=
Total mass of Sediment Disturbed (kg) ÷ Total Time Required (s) × Entrainment
Percentage
=
43200 kg ÷ (180 m ÷ 0.333 m/hr) × 20%
=
43200 kg ÷ 540hr × 20%
= 16
kg/hr
= 0.0044 kg/s
Suspended Solids Dispersion
Table 5.13 Predicted
Maximum Elevation in Suspended Solid and Sediment Deposition at WSRs from
Marine Dredging at Submarine Outfall
WSR (ID) |
SS Elevation (mg/L) |
Sediment Deposition (g/m2/day) |
|||||||
Wet Season |
Dry Season |
Criteria |
Wet Season |
Dry Season |
|||||
Criteria |
Max |
Compliance Time % |
Criteria |
Max |
Compliance Time % |
Max |
Max |
||
Fish
Culture Zone (Depth-averaged) |
|||||||||
Sha Tau Kok |
1.83 |
0.0267 |
100.00% |
2.63 |
0.0001 |
100.00% |
- |
- |
- |
Ap Chau |
1.83 |
0.0000 |
100.00% |
2.63 |
0.0000 |
100.00% |
- |
- |
- |
Kat O |
1.21 |
0.0000 |
100.00% |
2.66 |
0.0000 |
100.00% |
- |
- |
- |
O Pui Tong |
1.21 |
0.0000 |
100.00% |
2.66 |
0.0000 |
100.00% |
- |
- |
- |
Sai Lau Kong |
1.01 |
0.0000 |
100.00% |
2.55 |
0.0000 |
100.00% |
- |
- |
- |
Wong Wan |
1.01 |
0.0000 |
100.00% |
2.55 |
0.0000 |
100.00% |
- |
- |
- |
Temporary Relocation Zone of Fish Rafts for the Sha
Tau Kok Fish Culture Zone (FCZ7) |
1.83 |
0.0541 |
100.00% |
2.63 |
0.0080 |
100.00% |
- |
- |
- |
Temporary Relocation Zone of Fish Rafts for the Sha
Tau Kok Fish Culture Zone (FCZ8) |
1.83 |
0.0255 |
100.00% |
2.63 |
0.0004 |
100.00% |
- |
- |
- |
Spawning and Nursery Grounds of Commercial
Fisheries Resources |
1.83 |
0.0000 |
100.00% |
2.63 |
0.0000 |
100.00% |
- |
- |
- |
Seagrass
(Depth-averaged) |
|||||||||
Seagrass bed |
1.17 |
0.0003 |
100.00% |
2.33 |
0.0000 |
100.00% |
- |
0.0008 |
0.000 |
Mangrove
Stand (Depth-averaged) |
|||||||||
Off
STKFCZ |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Off
Wu Shek Kok |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Off
Tai Wan |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Off
Luk Keng |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Off
Kuk Po |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Kei
Shan Tsui |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Tai
Sham Chung |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
So
Lo Pun |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Pak
Kok Wan |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Yan
Chau Tong Marine Park |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Yan
Chau Tong Marine Park |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Yan
Chau Tong Marine Park |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Yan
Chau Tong Marine Park |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Ngau
Shi Wu Wan |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Horseshoe
Crab (Depth-averaged) |
|||||||||
Off
Muk Min Tau |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Off
Nga Yiu Tau |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Off
Pak Hok Lam |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
A
Chau |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Off
Luk Keng |
- |
0.0000 |
100.00% |
- |
0.0000 |
100.00% |
- |
- |
- |
Marine
Park (Depth-averaged) |
|||||||||
Yan Chau Tong (MP1) |
0.58 |
0.0000 |
100.00% |
1.15 |
0.0000 |
100.00% |
- |
- |
- |
Yan Chau Tong (MP2) |
0.58 |
0.0000 |
100.00% |
1.15 |
0.0000 |
100.00% |
- |
- |
- |
Coral
sites identified under this EIA (Bottom) |
|||||||||
Off Ah Kung Au (T1) |
2.47 |
0.0091 |
100.00% |
2.70 |
0.0009 |
100.00% |
100 |
0.0444 |
0.0881 |
Off Ah Kung Au (T2) |
2.47 |
0.0012 |
100.00% |
2.70 |
0.0001 |
100.00% |
100 |
0.0069 |
0.0460 |
Off Ah Kung Au (T3) |
2.47 |
0.0092 |
100.00% |
2.70 |
0.0008 |
100.00% |
100 |
0.0544 |
0.0659 |
Table 5.14 Predicted Cumulative Maximum
Elevation in Suspended Solid at WSRs from all Concurrent Marine Works
WSR
(ID) |
SS
Elevation (mg/L) |
|||||||
Wet Season |
Dry Season |
|||||||
Criteria |
Project
alone |
Concurrent
Project alone |
Cumulative |
Criteria |
Project
alone |
Concurrent
Project alone |
Cumulative |
|
Fish Culture Zone (Depth-averaged) |
||||||||
Temporary Relocation Zone of Fish Rafts for the Sha
Tau Kok Fish Culture Zone (FCZ7) |
1.83 |
0.0541 |
0.2268 |
0.2809 |
2.63 |
0.0080 |
0.0190 |
0.0270 |
Temporary Relocation Zone of Fish Rafts for the Sha
Tau Kok Fish Culture Zone (FCZ8) |
1.83 |
0.0255 |
0.5226 |
0.5481 |
2.63 |
0.0004 |
0.0207 |
0.0211 |
Seagrass (Depth-averaged) |
||||||||
Seagrass bed |
1.17 |
0.0003 |
0.7914 |
0.7917 |
2.33 |
0.0000 |
0.0109 |
0.0109 |
Coral
sites identified under this EIA (Bottom) |
||||||||
Off Ah Kung Au (T1) |
2.47 |
0.0091 |
0.0159 |
0.0250 |
2.70 |
0.0009 |
0.0000 |
0.0009 |
Off Ah Kung Au (T2) |
2.47 |
0.0012 |
0.0289 |
0.0301 |
2.70 |
0.0001 |
0.0000 |
0.0001 |
Off Ah Kung Au (T3) |
2.47 |
0.0092 |
0.0604 |
0.0696 |
2.70 |
0.0008 |
0.0000 |
0.0008 |
DO Depletion
Table 5.15 Predicted Maximum Depletion in
Dissolved Oxygen at Selected WSRs from Sheetpile Removal at Submarine Outfall
WSR (ID) |
Wet Season |
Dry Season |
||||||||||
Max SS Elevation (mg/L) |
Max DO Depletion (mg/L) |
Allowed DO
Depletion (mg/L) |
Max SS Elevation (mg/L) |
Max DO Depletion (mg/L) |
Allowed DO
Depletion (mg/L) |
|||||||
Fish
Culture Zone (Depth-averaged) |
||||||||||||
Sha Tau Kok |
0.0267 |
0.0005 |
- |
0.0001 |
>0.0001 |
1.29 |
||||||
Temporary
Relocation Zone of Fish Rafts for the Sha Tau Kok Fish Culture Zone (FCZ7) |
0.0541 |
0.0009 |
- |
0.0080 |
0.0001 |
1.29 |
||||||
Temporary
Relocation Zone of Fish Rafts for the Sha Tau Kok Fish Culture Zone (FCZ8) |
0.0255 |
0.0004 |
- |
0.0004 |
>0.0001 |
1.29 |
||||||
Seagrass
(Depth-averaged) |
||||||||||||
Seagrass bed |
0.0003 |
>0.0001 |
0.84 |
>0.0001 |
>0.0001 |
2.29 |
||||||
Coral
sites identified under this EIA (Bottom) |
||||||||||||
Off Ah Kung Au (T1) |
0.0091 |
0.0002 |
2.20 |
0.0009 |
>0.0001 |
4.20 |
||||||
Off Ah Kung Au (T2) |
0.0012 |
>0.0001 |
2.20 |
0.0001 |
>0.0001 |
4.20 |
||||||
Off Ah Kung Au (T3) |
0.0092 |
0.0002 |
2.20 |
0.0008 |
>0.0001 |
4.20 |
||||||
Elevation of Nutrients
Table 5.16 Predicted Worst Case Elevation
of TIN and UIA and its comparison with the corresponding WQO Criteria
Unit: mg/L |
TIN |
UIA |
||||
|
WQO |
Background Level |
Allowed Elevation |
WQO |
Background Level |
Allowed Elevation |
MM1 |
0.3 |
0.10 |
0.20 |
0.021 |
0.002 |
0.019 |
MM2 |
0.3 |
0.07 |
0.23 |
0.021 |
0.001 |
0.020 |
MM3 |
0.3 |
0.07 |
0.23 |
0.021 |
0.001 |
0.020 |
MM7 |
0.3 |
0.06 |
0.24 |
0.021 |
0.001 |
0.020 |
Predicted Elevation
at Most Adversely Impacted Receivers |
||||||
Temporary Relocation
Zone of Fish Rafts for the Sha Tau Kok Fish Culture Zone (FCZ7) |
0.0000335 |
0.00000262 |
||||
Note: Annual mean of TIN
and UIA given in Table 5.2 were taken as the background level at each
EPD monitoring stations. |
Elevation
of Heavy Metals and Micro-organic Pollutants
Table 5.17 Predicted Maximum Elevation of
Pollutants at FCZ7 and its comparison with the corresponding Assessment
Criteria
Parameter |
Assessment Criteria (mg/L) |
Maximum
Contaminant Level (mg/kg) |
Predicted
Maximum Pollutant Elevation in Wet Season (mg/L) |
Predicted
Maximum Pollutant Elevation in Dry Season (mg/L) |
Arsenic |
25 |
16 |
1.88 × 10-2 |
2.12 × 10-2 |
Total PCBs |
0.03 |
0.018 |
2.12× 10-5 |
2.38 × 10-5 |
Total PAHs |
3 |
2.25 |
2.64 × 10-3 |
2.98 × 10-3 |
Other Marine Construction
General Construction Activities
Temporary or Accidental Discharge of Sewage Effluent from the STKSTW /
TSTP
·
Routine/ regular checking of the
equipment
·
Provision of dual power supply and backup
generator to eliminate the risk of failure of dual power supply;
·
Provision of standby equipment for all
treatment units;
·
24-hour monitoring on the operation of
TSTP;
·
Install a remote control and monitoring
system (SCADA) to allow off-site monitoring; and
·
Provision of onsite storage of raw sewage
up to 6 hours ([19]).
Pane 5.4 Hierarchy
of Design Measures to Prevent Emergency Discharge for the TSTP
Sewage Effluents from Construction Workforce
Spillage of Chemicals
Operation Phase
Selection of Assessment Years and Modelling Scenarios
Table 5.18 Tentative Timeline for the
Expanded STKSTW and TSTP
Year / Month |
TSTP |
STKSTW |
2017 |
Construction of TSTP |
- |
2018 |
Commissioning of
TSTP (ADWF: 2,500 m3/day) |
- |
2019 |
TSTP Operation |
Construction of Expanded STKSTW |
2020 |
TSTP Operation |
Construction of Expanded STKSTW |
2021 |
TSTP Operation |
Commissioning of
Expanded STKSTW Phase 1 (ADWF: 5,000 m3/day) |
2022 |
TSTP Operation |
Operation of the Expanded STKSTW Phase 1 operation |
2023-2029 |
- |
Expanded STKSTW Phase 1 operation |
2030 |
- |
Commissioning of
Expanded STKSTW Phase 2 (ADWF: 10,000 m3/day) |
Sewage Loading from STKSTW
Table 5.19 Pollution Load of Effluent
Discharged from the STKSTW in Modelled Scenarios
Parameters |
Unit |
Baseline |
Operation
(% change against
baseline) |
Year
2011 Actual Loading (Annual Average) (1) |
BOD5 |
g/day |
66400 |
400000 (502.4%) |
2463 |
SS |
g/day |
99600 |
600000 (502.4%) |
2342 |
TN |
g/day |
142760 |
240000 (68.1%) |
8690 |
TIN |
g/day |
104691 |
160000 (52.8%) |
5699 |
NH3-N |
g/day |
38069 |
40000 (5.1%) |
2194 |
Organic Nitrogen |
g/day |
38069 |
80000 (110.1%) |
2992 (2) |
NO3 and NO2 |
g/day |
66621 |
120000 (80.1%) |
3504 |
E. coli |
count/day |
2.49×107 |
1.50×108 (502.4%) |
8.69×105 |
Note: Loading for all parameters are calculated
based on the upper limit level stipulated in Table 5.12 and the corresponding ADWF.
(1) Actual
loading compiled based on measurements taking at STKSTW in 2011. Annual average of actual loading from STKSTW
in 2011 is presented here. The actual loading
from STKSTW (daily-varying) is used for water quality model verification. See Annex 5C for details.
(2) Actual
measurements data not available.
Reference has been made to the approved EIA of Tai Po Sewage Treatment
Works Stage 5. As given in Table A4.7 of
Appendix 4.1 of the approved EIA, the daily loading of organic nitrogen was
assumed to be 16,083 g/day, based on daily flow rate of 4,785 m3/day. This means the assumed concentration of
organic nitrogen from STKSTW is about 3.354 mg/L.
Background Pollution Loading
Verification of Water Quality Model
Near Field Dispersion Modelling
Table 5.20 Summary of Near Field
Dispersion Modelling Results
Scenario |
Ambient
Flow Velocity |
Probability |
Horizontal
Distance from the Outfall to the Edge of Near Field Region (m) |
Plume
Top Level (m from seabed level) |
Plume
Bottom Level (m from seabed level) |
Plume
Thickness (m) |
For Existing STKSTW |
||||||
Dry-10th |
10%ile of ambient |
0.2 |
841.38 |
2.00 |
1.01 |
0.99 |
Dry-50th |
50%ile of ambient |
0.6 |
84.49 |
2.00 |
1.95 |
0.05 |
Dry-90th |
90%ile of ambient |
0.2 |
14.61 |
2.00 |
1.94 |
0.06 |
Wet-10th |
10%ile of ambient |
0.2 |
401.55 |
2.00 |
1.60 |
0.40 |
Wet -50th |
50%ile of ambient |
0.6 |
36.27 |
2.00 |
1.96 |
0.04 |
Wet -90th |
90%ile of ambient |
0.2 |
5.02 |
2.00 |
1.90 |
0.10 |
Weighted Average (Dry Season) |
2.00 |
1.760 |
0.240 |
|||
Weighted Average (Wet Season) |
2.00 |
1.876 |
0.124 |
|||
For Proposed
Expanded STKSTW |
||||||
Dry-10th |
10%ile of ambient |
0.2 |
1011.08 |
7.15 |
6.52 |
0.63 |
Dry-50th |
50%ile of ambient |
0.6 |
2.57 |
7.15 |
3.58 |
3.57 |
Dry-90th |
90%ile of ambient |
0.2 |
15.37 |
7.15 |
1.14 |
6.01 |
Wet-10th |
10%ile of ambient |
0.2 |
168.31 |
6.31 |
5.68 |
0.62 |
Wet -50th |
50%ile of ambient |
0.6 |
103.94 |
4.84 |
3.56 |
1.28 |
Wet -90th |
90%ile of ambient |
0.2 |
65.00 |
4.29 |
1.72 |
2.57 |
Weighted
Average (Dry Season) |
7.15 |
3.680 |
3.470 |
|||
Weighted
Average (Wet Season) |
5.02 |
3.616 |
1.408 |
Outfall Tracer Modelling
Approach
·
2030 water quality baseline scenarios with 1,660 m3/day
ADWF from existing STKSTW
·
2030 operation scenario with 10,000 m3/day
ADWF from expanded STKSTW (at new submarine outfall)
Change in Pollutant
Dispersion Pattern from Different Discharge Locations
Major Zone of Impact from
Different Sources
Seasonal Difference
Table 5.21 Predicted Water Quality at WSRs - 2030 Baseline and 2030 Operation
WSR Name (WSR ID) |
Scenario |
Mean DO (mg/L) |
10th-Percentile DO (mg/L) |
Mean TIN (mg/L) |
Mean UIA (mg/L) |
Mean SS (mg/L) |
Geometric Mean E.coli (cfu./100 mL) |
Fish Culture Zones |
WQO (If applicable) |
N/A |
5 |
0.3 |
0.021 |
Increase < 30% |
610 |
Sha Tau Kok (FCZ1) |
2030
Baseline |
6.38 |
5.03 |
0.22 |
0.007 |
14.1 |
24 |
2030
Operation |
6.36 |
5.01 |
0.21 |
0.006 |
15.6 |
23 |
|
Temporary Relocation Zone of Fish Raft for the Sha Tau Kok Fish Culture Zone 1 (FCZ7) |
2030
Baseline |
6.82 |
5.82 |
0.15 |
0.004 |
11.9 |
7 |
2030
Operation |
6.67 |
5.72 |
0.20 |
0.005 |
13.4 |
7 |
|
Temporary Relocation Zone of Fish Raft for the Sha Tau Kok Fish Culture Zone 2 (FCZ8) |
2030
Baseline |
6.78 |
5.77 |
0.16 |
0.004 |
13.7 |
3 |
2030
Operation |
6.80 |
5.74 |
0.18 |
0.004 |
16.1 |
3 |
|
Ap Chau (FCZ2) |
2030
Baseline |
6.62 |
5.89 |
0.10 |
0.002 |
6.3 |
1 |
2030
Operation |
6.59 |
5.94 |
0.11 |
0.003 |
6.1 |
1 |
|
Kat O (FCZ3) |
2030
Baseline |
6.17 |
5.50 |
0.11 |
0.003 |
4.9 |
2 |
2030
Operation |
6.19 |
5.60 |
0.11 |
0.003 |
4.9 |
2 |
|
O Pui Tong (FCZ4) |
2030
Baseline |
6.13 |
5.31 |
0.14 |
0.003 |
3.0 |
1 |
2030
Operation |
6.10 |
5.33 |
0.15 |
0.003 |
2.9 |
1 |
|
Sai Lau Kong (FCZ5) |
2030
Baseline |
7.20 |
6.21 |
0.05 |
0.002 |
7.3 |
1 |
2030
Operation |
7.23 |
6.22 |
0.05 |
0.002 |
7.4 |
1 |
|
Wong Wan (FCZ6) |
2030
Baseline |
6.61 |
5.59 |
0.10 |
0.002 |
4.0 |
9 |
2030
Operation |
6.59 |
5.60 |
0.09 |
0.002 |
4.0 |
9 |
|
Spawning and Nursery Grounds of Commercial Fisheries Resources |
2030
Baseline |
6.62 |
5.89 |
0.10 |
0.002 |
6.3 |
1 |
2030
Operation |
6.59 |
5.94 |
0.11 |
0.003 |
6.1 |
1 |
|
Seagrass |
WQO (If applicable) |
N/A |
4 |
0.3 |
0.021 |
Increase < 30% |
N/A |
Seagrass (SG) |
2030
Baseline |
6.79 |
5.62 |
0.27 |
0.007 |
16.2 |
125 |
2030
Operation |
6.89 |
5.64 |
0.19 |
0.005 |
16.9 |
124 |
|
Mangrove stand |
WQO (If applicable) |
N/A |
4 |
0.3 |
0.021 |
N/A |
N/A |
Off STKSTW (M1) |
2030
Baseline |
7.07 |
6.20 |
0.40 |
0.010 |
14.9 |
2474 |
2030
Operation |
7.26 |
6.30 |
0.16 |
0.005 |
15.6 |
2513 |
|
Off Wu Shek Kok (M2) |
2030
Baseline |
7.00 |
6.47 |
0.17 |
0.005 |
17.5 |
455 |
2030
Operation |
7.15 |
6.57 |
0.13 |
0.004 |
20.3 |
460 |
|
Off Tai Wan (M3) |
2030
Baseline |
6.45 |
5.54 |
0.22 |
0.010 |
25.2 |
149 |
2030
Operation |
6.51 |
5.53 |
0.21 |
0.010 |
27.6 |
153 |
|
Off Luk Keng (M4) |
2030
Baseline |
6.70 |
5.99 |
0.12 |
0.004 |
26.4 |
1 |
2030
Operation |
6.84 |
6.06 |
0.11 |
0.004 |
30.7 |
1 |
|
Off Kuk Po (M5) |
2030
Baseline |
7.33 |
6.86 |
0.11 |
0.003 |
13.3 |
370 |
2030
Operation |
7.53 |
6.89 |
0.12 |
0.003 |
16.0 |
400 |
|
Kei Shan Tsui (M6) |
2030
Baseline |
7.67 |
7.05 |
0.07 |
0.002 |
12.3 |
1 |
2030
Operation |
7.76 |
7.39 |
0.10 |
0.002 |
13.2 |
2 |
|
Tai Sham Chung (M7) |
2030
Baseline |
7.75 |
7.06 |
0.09 |
0.002 |
9.9 |
1 |
2030
Operation |
7.83 |
7.27 |
0.13 |
0.002 |
10.5 |
1 |
|
So Lo Pun (M8) |
2030
Baseline |
7.34 |
6.35 |
0.05 |
0.001 |
5.7 |
6 |
2030
Operation |
7.47 |
6.39 |
0.05 |
0.001 |
6.6 |
6 |
|
Pak Kok Wan (M9) |
2030
Baseline |
7.40 |
6.58 |
0.05 |
0.001 |
5.2 |
1 |
2030
Operation |
7.50 |
6.60 |
0.05 |
0.001 |
5.7 |
1 |
|
Yan Chau Tong Marine Park (M10) |
2030
Baseline |
7.02 |
6.22 |
0.04 |
0.002 |
5.9 |
456 |
2030
Operation |
7.07 |
6.26 |
0.03 |
0.002 |
6.1 |
458 |
|
Yan Chau Tong Marine Park (M11) |
2030
Baseline |
7.06 |
6.05 |
0.04 |
0.002 |
8.7 |
56 |
2030
Operation |
7.13 |
6.10 |
0.04 |
0.002 |
8.9 |
56 |
|
Ngau Shi Wu Wan (M12) |
2030
Baseline |
7.28 |
6.33 |
0.04 |
0.001 |
5.8 |
1 |
2030
Operation |
7.31 |
6.41 |
0.03 |
0.001 |
5.9 |
1 |
|
Yan Chau Tong Marine Park (M13) |
2030
Baseline |
6.67 |
6.10 |
0.03 |
0.001 |
1.4 |
1 |
2030
Operation |
6.66 |
6.09 |
0.03 |
0.001 |
1.5 |
1 |
|
Yan Chau Tong Marine Park (M14) |
2030
Baseline |
6.71 |
6.07 |
0.03 |
0.001 |
1.8 |
1 |
2030
Operation |
6.69 |
6.07 |
0.03 |
0.001 |
1.9 |
1 |
|
Coral sites identified under this EIA |
WQO (If applicable) |
N/A |
4 |
0.3 |
0.021 |
Increase < 30% |
N/A |
Off Ah Kung Au (T1) |
2030
Baseline |
6.52 |
5.77 |
0.11 |
0.004 |
14.3 |
3 |
2030
Operation |
6.50 |
5.75 |
0.10 |
0.004 |
14.7 |
3 |
|
Coral sites identified under this EIA (T2) |
2030
Baseline |
6.53 |
5.78 |
0.12 |
0.004 |
14.5 |
3 |
2030
Operation |
6.51 |
5.74 |
0.10 |
0.004 |
14.9 |
3 |
|
Coral sites identified under this EIA (T3) |
2030
Baseline |
6.53 |
5.76 |
0.13 |
0.004 |
14.7 |
3 |
2030
Operation |
6.52 |
5.72 |
0.11 |
0.003 |
15.0 |
3 |
|
Horseshoe crab |
WQO (If applicable) |
N/A |
4 |
0.3 |
0.021 |
N/A |
N/A |
Off Muk Min Tau (H1) |
2030
Baseline |
6.97 |
6.12 |
0.28 |
0.007 |
13.8 |
265 |
2030
Operation |
7.12 |
6.16 |
0.15 |
0.004 |
15.9 |
277 |
|
Off Pak Hok Lam (H2) |
2030
Baseline |
6.93 |
6.19 |
0.24 |
0.006 |
10.6 |
224 |
2030
Operation |
7.07 |
6.21 |
0.15 |
0.004 |
12.6 |
203 |
|
Off Nga Yiu Tau (H3) |
2030
Baseline |
7.00 |
6.47 |
0.17 |
0.005 |
17.5 |
455 |
2030
Operation |
7.15 |
6.57 |
0.13 |
0.004 |
20.3 |
460 |
|
A Chau (H4) |
2030
Baseline |
5.86 |
4.24 |
0.26 |
0.013 |
38.2 |
902 |
2030
Operation |
5.92 |
4.22 |
0.25 |
0.012 |
41.3 |
916 |
|
Off Luk Keng (H5) |
2030
Baseline |
6.70 |
5.99 |
0.12 |
0.004 |
26.4 |
1 |
2030
Operation |
6.84 |
6.06 |
0.11 |
0.004 |
30.7 |
1 |
|
Marine Park |
WQO (If applicable) |
N/A |
4 |
0.3 |
0.021 |
Increase < 30% |
N/A |
Yan Chau Tong (MP1) |
2030
Baseline |
6.45 |
5.39 |
0.08 |
0.003 |
6.4 |
1 |
2030
Operation |
6.49 |
5.43 |
0.08 |
0.003 |
6.5 |
1 |
|
Yan Chau Tong (MP2) |
2030
Baseline |
6.59 |
5.72 |
0.07 |
0.002 |
5.2 |
1 |
2030
Operation |
6.61 |
5.75 |
0.07 |
0.002 |
5.3 |
1 |
Values
not fulfilling the relevant WQO criteria are underlined and bolded.
·
Routine/ regular checking to the equipment
·
Provision of dual power supply and backup generator
to eliminate the risk of power failure;
·
Provision of standby equipment (online and
on-shelf) for all treatment units;
·
Operation of STKSTW is under 24-hour monitoring by
Shift Team of Sha Tau Kok (for new STKSTW) and/or Shek Wu Hui STW in order to
allow inspection and any necessary repair works by DSD at the earliest possible
time;
·
A remote control and monitoring system (SCADA) will
also be installed to allow off-site DSD staff (Shift Team) to monitor the
operation of STKSTW; and
·
Provision of on-site storage of raw sewage up to 6
hours for the TSTP and STKSTW ([20]).
Pane 5.5 Hierarchy
of Design Measures to Prevent Emergency Discharge for the Expanded STKSTW
·
2 duties + 1 standby fine screens would be
provided;
·
Uninstalled spare parts would be provided;
·
Monitoring equipment of fine screens would be
installed;
·
Routine inspection and scheduled maintenance works
would be strengthened and carried out regularly; and
·
Equipment and necessary measures such as lifting
opening would be provided to shorten the time required for replacement of
screen.
·
Operation of STKSTW will be under 24-hour
monitoring by Shift Team of STKSTW or Shek Wu Hui Sewage Treatment Works
(SWHSTW). A remote control and monitoring system (SCADA) will also be installed
to allow off-site DSD staff (Shift Team) to on-line monitor the operation of
STKSTW and take swift action if needed.
·
Proper and regular maintenance will be conducted,
and additional spare parts for replacement of the chain for the fine screen
will be provided.
·
6 hours of emergency storage ([22]) will be provided which is
sufficient for replacing the chains provided that the spare parts are already
available on site.
·
The travelling time from SWHSTW to STKSTW is within
30 minutes. Any inspection and necessary
supporting works by DSD in-house staff could be able to reach STKSTW very soon.
·
From the commissioning day of STKSTW, there is no
overflow at STKSTW so far.
Construction Phases
·
All vessels should be well maintained and inspected
before use to limit any potential discharges to the marine environment;
·
All vessels must have a clean ballast system;
·
No discharge of sewage/grey wastewater should be
allowed. Wastewater from potentially
contaminated area on working vessels should be minimized and collected. These kinds of wastewater should be brought
back to port and discharged at appropriate collection and treatment system; and
·
No soil waste is allowed to be disposed overboard.
General Construction Activities
·
Silt removal facilities such as silt traps or
sedimentation facilities will be provided to remove silt particles from runoff
to meet the requirements of the TM standard under the WPCO. The design of silt removal facilities will be
based on the guidelines provided in ProPECC
PN 1/94. All drainage facilities and
erosion and sediment control structures will be inspected on a regular basis
and maintained to confirm proper and efficient operation at all times and
particularly during rainstorms.
Deposited silt and grit will be removed regularly.
·
Earthworks to form the final surfaces will be
followed up with surface protection and drainage works to prevent erosion
caused by rainstorms.
·
Appropriate surface drainage will be designed and
provided where necessary.
·
The precautions to be taken at any time of year
when rainstorms are likely together with the actions to be taken when a
rainstorm is imminent or forecasted and actions to be taken during or after
rainstorms are summarised in Appendix A2 of ProPECC
PN 1/94.
·
Oil interceptors will be provided in the drainage
system where necessary and regularly emptied to prevent the release of oil and
grease into the storm water drainage system after accidental spillages.
·
Temporary and permanent drainage pipes and culverts
provided to facilitate runoff discharge, if any, will be adequately designed
for the controlled release of storm flows.
·
The temporary diverted drainage, if any, will be
reinstated to the original condition when the construction work has finished or
when the temporary diversion is no longer required.
Spillage of Chemicals
Operation Phase
·
Routine/ regular checking to the equipment
·
Provision of dual power supply and backup generator
to eliminate the risk of power failure;
·
Provision of standby equipment (online and
on-shelf) for all treatment units;
·
Operation of STKSTW is under 24-hour monitoring by
Shift Team of Sha Tau Kok (for new STKSTW) and/or Shek Wu Hui STW in order to
allow inspection and any necessary repair works by DSD at the earliest possible
time;
·
A remote control and monitoring system (SCADA) will
also be installed to allow off-site DSD staff (Shift Team) to monitor the
operation of STKSTW; and
·
Provision of on-site storage of raw sewage up to 6
hours for the TSTP and STKSTW ([23]).
·
2 duties + 1 standby fine screens would
be provided;
·
Uninstalled spare parts would be
provided;
·
Monitoring equipment of fine screens
would be installed;
·
Routine inspection and scheduled
maintenance works would be strengthened and carried out regularly; and
·
Equipment and necessary measures such as lifting
opening would be provided to shorten the time required for replacement of
screen.
Construction Phase
Operation Phase
·
Emergency discharge events are considered accident,
which should rarely occurs. The
incidence should be even lower with the built-in design preventive
measures. Therefore, the frequency of
such even is extremely low.
·
The provision of temporary storage ([24]) should effectively eliminate any
need of emergency discharge. The assumed
2-hour discharge scenario is already a conservative assumption. Therefore, the duration of such even is
short.
·
In case such event happens, the discharge of
untreated sewage would be ended after the maintenance works. Based on the modelling prediction, the water
quality would recover in short period of time (<10 days).
·
The mixing of UIA from such event is quite
localized and covers only a stretch of shoreline along the STKSTW. The mixing zone would gradually shrink after
the end of emergency discharge.
·
The WSRs are not considered particularly vulnerable
to a short term elevation of UIA.
·
The impacted area / WSRs are not considered to be
of international and regional importance.
·
The temporary elevation of UIA would not result in
exceedance of WQO UIA criteria, which considers annual average of the
parameter.
Table 5.22 Nearby Projects Identified
Project |
Duration |
Location |
Major Marine Activity / Sewage Discharge |
North District sewerage, stage 2 part 2A - Pak Hok Lam trunk sewer and Sha Tau Kok village sewerage |
2012 - 2017 |
Pak Hok Lam and Sha Tau Kok Village |
Increase sewage flow
to STKSTW |
Sediment Removal at Sha Tau Kok Fish Culture Zone, Boat Shelter and Approach Channel |
2017-2018 (Tentative) |
Sha Tau Kok Fish
Culture Zone, Boat Shelter and Approach Channel |
(1) Sediment dredging (2) Temporary relocation of fish rafts |
Drainage Improvement Works at North District, including various drainage improvement measures in Sha Tau Kok. |
2016 – 2020 |
Sha Tau Kok Town
area |
Drainage improvement
works in Sha Tau Kok Town area |
North
District sewerage, stage 2 part 2A - Pak Hok Lam trunk sewer and Sha Tau Kok
village sewerage
Sediment
Removal at Sha Tau Kok Fish Culture Zone, Boat Shelter and Approach Channel
Drainage
Improvement Works at North District, including various drainage improvement
measures in Sha Tau Kok
Construction Phase
Operation Phase
([1])
CEDD (2008). Project Profile for Sediment Removal at Sha
Tau Kok Fish Culture Zone, Boat Shelter and Approach Channel. Submitted under EIAO with Application No.
ESB-186/2008.
([2]) ERM
– Hong Kong, Ltd (2007) EIA for Development of a Bathing Beach at Lung Mei, Tai
Po. For Civil Engineering Department,
Hong Kong SAR Government.
([3]) ERM
- HK Ltd (2010). Development of an Offshore Wind Farm in Hong Kong. Final
Environmental Impact Assessment. For the
Hong Kong Electric Company
([4]) Black
& Veatch Hong Kong Ltd - Desalination Plant at Tseung Kwan O – Feasibility
Study, For Water Supplies Department, Hong Kong SAR Government.
([5]) ERM
– Hong Kong, Ltd (2002) EIA for the Proposed Submarine Gas Pipeline from Cheng
Tou Jiao Liquefied Natural Gas Receiving Terminal, Shenzhen to Tai Po Gas Production
Plank, Hong Kong. Final EIA Report. For the Hong Kong and China Gas Co., Ltd.
([6]) Maunsell
Consultant Asia Ltd, (2007). Wan Chai Development Phase II and Central-Wan Chai
Bypass. EIA-141/2007.
([7]) Maunsell (2002). EIA for Decommissioning of Cheoy Lee Shipyard at Penny's Bay. For Civil Engineering Department, Hong Kong SAR Government.
([8]) ERM – Hong Kong (1997). EIA for Disposal of Contaminated Mud in the East Sha Chau Marine Borrow Pit. For Civil Engineering Department, Hong Kong SAR Government.
([9]) Maunsell (2001). EIA for Wanchai Development Phase II - Comprehensive Feasibility Study. For Territory Development Department, Hong Kong SAR Government.
([11]) BMT Asia Pacific Ltd (2009). EIA for Hong Kong Offshore Wind Farm in Southeastern Waters. For HK Offshore Wind Limited
([12]) ERM - HK Ltd (2010). Development of an Offshore Wind Farm in Hong Kong. Final Environmental Impact Assessment. For the Hong Kong Electric Company
([13]) In 2008, Hong Kong and Shenzhen initiated the first review study of the “Mirs Bay Water Quality Regional Control Strategy”. The study was completed on schedule in 2011. The study findings indicated that, with progressive extension and improvement of sewerage infrastructure, the overall pollution load to Mirs Bay would hold steady in the next five to ten years and that the water quality of the bay could remain good. Both sides agreed to continue to implement the jointly formulated water quality control strategy for protecting the Mirs Bay water environment and meeting the sustainable development objectives. With the continuous efforts by both sides of the government to implement pollution control measures to reduce wastewater discharge, it is expected that the pollution situations in the future would not be worse than the 2004 conditions as assumed in the approved EIA for Tai Po STW Stage V. Source: EPD (http://wqrc.epd.gov.hk/en/regional-collaboration/deep-bay.aspx)
([14]) AECOM (2011) Development of
the Integrated Waste Management Facilities Phase 1, for EPD. Register No.:
AEIAR-163/2012, http://www.epd.gov.hk/eia/register/report/eiareport/eia_2012011/index.htm
([15]) Mott MacDonald (2010) South
Island Line (East) Environmental Impact Assessment, for MTR. Register No.:
AEIAR-155/2010 http://www.epd.gov.hk/eia/register/report/eiareport/eia_1852010/Index.html
([16]) AECOM (2009) Tuen Mun – Chek
Lap Kok Link, for HyD. Register No.: AEIAR-146/2009 http://www.epd.gov.hk/eia/register/report/eiareport/eia_1742009/index.html
([17])
The dimension provided are rounded-up for conservative calculation. Based on the latest available information, the
actual footprint is 54 m × 22 m, which is slightly smaller.
([18])Juliane Finn and Rosie Berger, 2007. Measurement of Dissolved Oxygen in Lakes and Ponds during Light and Dark Conditions. http://depts.alverno.edu/nsmt/archive/bergerfinn.htm
([20]) The storage volume for the TSTP and the expanded STKSTW are 625 m3 and 2,500 m3 respectively.
([21])
EPD’s submission to The Legislative Council - Panel on Environmental. Affairs, September 2014. Available at: http://www.legco.gov.hk/yr13-14/english/panels/ea/papers/eacb1-1989-1-e.pdf
([22]) The storage volume for the TSTP and the expanded STKSTW are 625 m3 and 2,500 m3 respectively.
([23]) The storage volume for the TSTP and the expanded STKSTW are 625 m3 and 2,500 m3 respectively.