4.
WATER QUALITY MONITORING
4.1
Monitoring Locations
4.1.1
The
water monitoring works for the Contract are covered by Contract No. HY/2013/04 ¡§Hong
Kong-Zhuhai-Macao-Bridge HKBCF ¡V Infrastructure Works Stage II (Southern Portion)¡¨.
The ET of the Contract or another ET of the HZMB project is required to conduct
impact water quality monitoring at the stations shown in Table 4.1 and Figure 3.
Table 4.1 Water Quality
Monitoring Stations
Station |
Description |
Easting |
Northing |
IS5 |
Impact
Station (Close to HKBCF construction site) |
811579 |
817106 |
IS(Mf)6 |
Impact
Station (Close to HKBCF construction site) |
812101 |
817873 |
IS7 |
Impact Station (Close to HKBCF construction site) |
812244 |
818777 |
IS8 |
Impact
Station (Close to HKBCF construction site) |
814251 |
818412 |
IS(Mf)9 |
Impact
Station (Close to HKBCF construction site) |
813273 |
818850 |
IS10(N) |
Impact Station (Close to HKBCF construction site) |
812942 |
820881 |
IS(Mf)11 |
Impact
Station (Close to HKBCF construction site) |
813562 |
820716 |
IS(Mf)16 |
Impact Station
(Close to HKBCF construction site) |
814328 |
819497 |
IS17 |
Impact
Station (Close to HKBCF construction site) |
814539 |
820391 |
SR3(N) |
Sensitive
receivers (San Tau SSSI) |
810689 |
816591 |
SR4(N) |
Sensitive
receivers (Tai Ho) |
814705 |
817859 |
SR5(N) |
Control
Station |
812569 |
821475 |
SR6 |
Sensitive
receivers (Sha Chau and Lung Kwu Chau Marine Park) |
805837 |
821818 |
SR7 |
Sensitive
receivers (Tai Mo Do) |
814293 |
821431 |
SR10A(N)(1) |
Sensitive
receivers (Ma Wan FCZ) 1 |
823644 |
823484 |
SR10B(N2)(1) |
Sensitive
receivers (Ma Wan FCZ) 2 |
823689 |
823159 |
CS(Mf)3(N) |
Control Station |
808814 |
822355 |
CS(Mf)5 |
Control
Station |
817990 |
821129 |
CS4 |
Control
Station |
810025 |
824004 |
CS6 |
Control
Station |
817028 |
823992 |
CSA(2) |
Control
Station |
818103 |
823064 |
Note:
(1) Additional monitoring
station for Ma Wan FCZ
(2) Additional control
monitoring station for Ma Wan FCZ
Remarks:
The
ET of the Contract should conduct impact water quality monitoring at the WQMs
listed in the table as part of EM&A programme according to latest
notification from ENPO if water quality monitoring is no longer covered by
another ET of the HZMB project. The ET of the Contract shall communicate and
share the monitoring data to the ET(s) of the other contracts if the water
quality monitoring station(s) is/are as part of EM&A programme.
4.2
Monitoring Requirements
4.2.1
The
monitoring requirements, monitoring equipment, monitoring parameters, frequency
and duration, monitoring methodology, monitoring schedule, meteorological
information are detailed in the monthly EM&A Reports prepared by Contract No.
HY/2013/04.
4.2.2
The
event and action plan is provided in Appendix
C.
4.2.3
The
Action and Limit Levels for Water Quality are provided in Table 4.2.
Table 4.2 Action and Limit Levels for Water
Quality
Parameters |
Action |
Limit |
DO in mg/L (Surface,
Middle & Bottom) |
Surface and Middle 5.0 Bottom 4.7 |
Surface and
Middle = 4.2 (except 5 mg/L for FCZ) Bottom = 3.6 |
SS in mg/L
(depth-averaged) at all monitoring stations and control stations |
23.5 and 120%
of upstream control station's SS at the same tide of the same day* |
34.4 and 130%
of upstream control station's SS at the same tide of the same day and 10mg/L
for WSD Seawater intakes* |
Turbidity in NTU
(depth-averaged) |
27.5 and 120%
of upstream control station's turbidity at the same tide of the same day* |
47.0 and 130%
of upstream control station's turbidity at the same tide of the same day* |
* Remarks: Reference
is made to EPD approval of adjustment of water quality assessment criteria
issued and became effective on 18 February 2013.
Notes:
1. ¡¨depth-averaged" is calculated by taking the arithmetic
means of reading of all three depths.
2.
For DO, non-compliance of the water quality limits occurs when monitoring
result is lower than the limits.
3.
For turbidity, SS, non-compliance of the water quality limits occurs when monitoring
result is higher than the limits.
4.
All the figures given in the table are used for reference only and the EPD may
amend the figures whenever it is considered as necessary.
5.
The 1%-ile of baseline data for dissolved oxygen
(surface and middle) and dissolved oxygen (bottom) are 4.2mg/L and 3.6mg/L
respectively.
4.2.4
If
exceedance(s) at these stations is/are recorded by the ET of the Contract or
referred by the other ET under the HZMB project to the Contract, the ET of the
Contract will carry out an investigation and findings will be reported in the
monthly EM&A Report.
4.3
Monitoring Results
4.3.1
The monitoring and investigation results for the monitoring
stations showed in Table 4.1 are
reported in the monthly EM&A Report prepared for Contract No. HY/2013/04. There
were Action Level exceedances recorded on two days during the reporting period.