5.1
In
accordance with the Updated EM&A Manual, impact water quality monitoring
shall be carried out three days per week at all the designated monitoring
stations during the construction period. The measurement periods are during the
construction of channel specified in Table 4.1 of the Updated
EM&A Manual. The interval between two sets of monitoring shall not be less
than 36 hours.
5.2
Replicate
in-situ measurements of Dissolved Oxygen (DO), temperature, turbidity, pH,
Suspended Solids (SS) and samples for Suspended Solids (SS), ammonia nitrogen,
unionized ammonia, nitrate nitrogen and orthophosphate from each independent
sampling event were collected to ensure a robust
statistically interpretable database.
5.3
Appendix B shows the established Action and Limit Levels for the water quality
monitoring work according to the Updated EM&A Manual and Baseline Water Quality Monitoring
Report (KTN & FLN NDA).
5.4
Table 5.1 summarises the monitoring parameters,
monitoring periods and frequencies of the water quality monitoring.
Table 5.1 Water
Quality Monitoring Parameters and Frequency
|
Parameters, unit |
Depth |
Frequency |
|
·
Temperature(°C) ·
pH(pH
unit) ·
turbidity
(NTU) ·
water
depth (m) ·
salinity
(ppt) ·
DO
(mg/L and % of saturation) ·
SS
(mg/L) ·
Ammonia Nitrogen (NH3-N) (mg NH3-N/L) ·
Unionized Ammonia (UIA) (mg/L) ·
Nitrate-nitrogen (NO3-N) (mg NO3--N/L) ·
Ortho-phosphate (PO4) (mg PO43--P/L) |
· 3 water depths: 1m
below water surface, mid-depth and 1m above river bed. · If the water depth was
less than 3m, mid-depth sampling only. · If water depth was
less than 6m, mid-depth may be omitted. |
3
days per week during construction
of channel |
5.5
According to Section 5.6.1.2 of the approved EIA Report, the potential water quality
impact during construction is due to the alternation of natural streams (i.e.
channelization of Ma Tso Lung Stream and Siu Hang San Tsuen Stream) as these
two streams are the ecologically important streams.
5.6
No construction of channel was carried out at Ma Tso
Lung Stream and Siu Hang San Tsuen Stream during the reporting month.
Therefore, no water quality monitoring was conducted.
Additional Water Quality Monitoring
5.7
Additional Water Quality Monitoring shall be carried
out at River Beas, River Indus and near Siu Hang San Tsuen Stream three days
per week at all designated monitoring stations during the construction period.
The measurement period are during the construction
site drainage along River Beas, construction of footbridge across River Beas
and during construction of bridge across River Indus.
5.8
Replicate in-situ measurement and samples from each
independent sampling event were collected to ensure a robust statistically
interpretable database. DO, temperature, turbidity and pH were measured in-situ
whereas SS and arsenic were determined by an accredited laboratory. Other
relevant data, including monitoring location / position, time, water depth,
weather conditions and any special phenomena or work underway at the
construction site were recorded.
5.9
For all the monitoring stations, sampling were taken at 3 water depths, namely 1m below the water
surface, mid depth and 1m above the river bed. For stations that were less than 3m in depth, only the mid depth sample
was taken. Should the water depth was less than 6m, in which case the mid-depth station may have been omitted. The interval between two sampling surveys
was not less than 36 hours.
5.10
Appendix B
shows the established Action and Limit Levels for the environmental monitoring
works.
5.11
Additional
impact water quality monitoring was conducted at 6 monitoring stations (SYR-CS1,
SYR-IS1, NTR-CS1, NTR-IS1, SHST-IS2, MWR-IS3) which are summarised
in Table 5.2. The location of
monitoring stations is shown in Figures
5 and 6.
Table
5.2 Additional Water
Quality Monitoring Stations
|
Station |
Description |
Locations |
Measurement
Periods |
|
River Beas |
|||
|
SYR-CS1 |
Control
Station |
Upstream
of river |
During the construction site drainage
along River Beas and construction of the footbridge
across River Beas |
|
SYR-IS1 |
Impact
Station |
Downstream
of river |
|
|
River Indus and near Siu Hang San Tsuen
Stream |
|||
|
NTR-CS1 |
Control Station |
Upstream of river |
During
construction of the bridge
across River Indus |
|
NTR-IS1 |
Impact Station |
Downstream of river |
|
|
SHST-IS2 |
Impact Station |
Water sensitive receiver at near Siu
Hang San Tsuen Stream |
|
|
MWR-IS3 |
Impact Station |
Water sensitive receiver at near Ma Wat River |
|
5.12
Multi-parameter
meters (Model YSI EXO) were used
to measure DO, turbidity, salinity, pH and temperature.
Dissolved
Oxygen (DO) and Temperature Measuring Equipment
5.13
The instrument
for measuring dissolved oxygen and temperature should be portable and
weatherproof complete with cable, sensor, and use DC power source. The
equipment was capable of measuring:
·
A
dissolved oxygen level in the range of 0-20mg/L and 0-200% saturation; and
·
The
temperature within 0-45 degree Celsius.
5.14
The equipment
had a membrane electrode with automatic temperature compensation complete with
a cable.
5.15
Sufficient
stocks of spare electrodes and cables were available for replacement where
necessary.
5.16
Salinity
compensation was built-in in the DO equipment. In-situ salinity was measured to calibrate the DO equipment prior
to each DO measurement.
5.17
Turbidity was
measured in situ by using the nephelometric method. The instrument was
portable and weatherproof using a DC power sources
complete with cable, sensor and comprehensive operation manuals. The equipment
was capable of measuring turbidity between 0-1000 NTU. The probe cable was not
less than 25m in length. The meter was calibrated in order to
establish the relationship between NTU units and the levels of Suspended
Solids.
5.18
A portable
salinometer capable of recording salinity within the range of 0-40 parts per
thousand (ppt) was used for salinity measurement.
5.19
A portable,
battery-operated and hand held echo sounder was used
for the determination of water depth at each designated monitoring station.
pH
5.20
The instrument consisted
of a potentiometer, a glass electrode, a reference electrode and a temperature-compensating
device. It was readable to 0.1pH in a range of 0 to 14. Standard buffer
solutions of at least pH 7 and pH 10 were used for calibration of the
instrument before and after use.
Water Sampling for
Laboratory Analysis
5.21
A water sampler, consisting of a
transparent Polyvinyl Chloride (PVC) of a capacity of not less than two litres which can be effectively sealed with cups at both
ends was used. The water sampler had a positive latching system to keep it open
and prevent premature closure until released by a messenger when the sampler
was at the selected water depth. In addition, a sampling cup attached to a
fixed or extendable rod was also used for sampling at the monitoring stations
with swallow water.
Sample Container and Storage
5.22
Following collection, water samples for
laboratory analysis were stored in high density polyethylene bottles with
appropriate preservatives added, packed in the ice (cooled to 4oC
without being frozen). The samples were
delivered to WELLAB Limited (HOKLAS Registration No. HOKLAS083) and analysed
as soon as possible after collection of the water samples. Sufficient volume of
samples was collected to achieve the detection limit.
Calibration of In Situ
Instruments
5.23
The pH meter, DO meter and turbidimeter
were checked and calibrated before use. DO meter and turbidimeter were
certified by WELLAB Limited before use and subsequently re-calibrated at
quarterly basis throughout all stage of water quality monitoring programme. Response of sensors and electrodes were checked
with certified standard solutions before each use. Wet bulb calibration for a
DO meter was carried out before measurement at each monitoring station.
5.24
For on-site calibration of field equipment
(Multi-parameter Water Quality System), the standard BS 1427:2009 “Guide to on-site test
methods for analysis of waters” was observed.
Back-up Equipment
5.25
Sufficient stocks of spare parts were
maintained for replacements when necessary. Backup monitoring equipment was
also be made available so that monitoring could proceed uninterrupted even when some
equipment was under
maintenance, calibration, etc.
5.26
Table 5.3 summarises the equipment used in the
water quality monitoring programme. Copies
of the calibration certificates of the multi-parameter
water quality systems are
shown in Appendix C.
Table
5.3 Water Quality
Monitoring Equipment
|
Equipment |
Model and Make |
Qty. |
|
Water
sampler and sampling cup |
A
2-Litre transparent PVC cylinder with latex cups at both ends and sampling
cup for monitoring stations with swallow water |
1 |
|
Sonar
Water Depth Detector |
Garmin
Striker plus 4 |
1 |
|
Multi-parameter
Water Quality System |
YSI
EXO 1 |
1 |
5.27
Table 5.4
summarises the monitoring parameters and frequencies
of the additional water quality monitoring. The water quality monitoring
schedule for the reporting month is shown in Appendix D.
Table
5.4 Additional Water
Quality Monitoring Parameters and Frequency
|
Monitoring Station(s) |
Parameters, unit |
Depth |
Frequency |
|
|
River Beas |
SYR-CS1 SYR-IS1 |
·
Temperature (oC) ·
pH (pH unit) ·
Turbidity (NTU) ·
Water depth (m) ·
Salinity (ppt) ·
Dissolved Oxygen (DO) (mg/L and % of
saturation) ·
Suspended Solids (SS) (mg/L) ·
Arsenic (As) (µg/L) |
·
3 water depths: 1m below water surface,
mid-depth and 1m above river bed. ·
If the water depth was less than 3m,
mid-depth sampling only. ·
If water depth was less than 6m,
mid-depth might be omitted. |
3 days per
week |
|
River Indus
and near Siu Hang San Tsuen Stream |
NTR-CS1 NTR-IS1 SHST-IS2 MWR-IS3 |
·
Temperature (oC) ·
pH (pH unit) ·
Turbidity (NTU) ·
Water depth (m) ·
Salinity (ppt) ·
Dissolved Oxygen (DO) (mg/L and % of
saturation) ·
Suspended Solids (SS) (mg/L) |
||
5.28
Monitoring location and position, time,
sampling depth, weather conditions and any special phenomena or work underway
nearby was also recorded.
Instrumentation
5.29
Multi-parameter meters (Model YSI EXO) were used to measure DO, turbidity, salinity,
pH and temperature.
Operating/Analytical Procedures
5.30
At each measurement, two consecutive
measurements of DO concentration, DO saturation, salinity, turbidity, pH and temperature
were taken. The probes were retrieved out of the water after the first
measurement and then re-deployed for the second measurement. Where the
difference in the value between the first and second readings of each set was
more than 25% of the value of the first reading, the reading was discarded and
further readings were taken.
Laboratory Analytical Methods
5.31
Duplicate samples from each independent
sampling event were required
for all parameters.
Analysis of suspended solids and arsenic were carried out by WELLAB Ltd. and
comprehensive quality assurance and control procedures were in place in order to
ensure the quality and consistency in results. The analysis
methods and limits of reporting are
provided in Table 5.5.
Table
5.5 Method for
Laboratory Analysis for Water Samples
|
Determinant |
Proposed
Method |
Limit
of Reporting |
|
Total Suspend Solids
(SS) |
APHA 17ed 2540 D |
2.5 mg/L |
|
Arsenic (As) |
In-house method SOP022 (ICP-AES)
and SOP076 (ICP-MS) |
1 µg/L |
5.32
Water sampling equipment used during the course of the monitoring process was
decontaminated by manual washing and rinsed with distilled water after each
sampling event. All of the disposal equipment was
discarded after the sampling.
Sampling Management and
Supervision
5.33
All sampling bottles were labelled with
the sample I.D. (including sampling station), laboratory
number and sampling date. Water samples were dispatched to the testing
laboratory for analysis as soon as possible. All the collected samples were
stored in a cool box to keep the temperature less than 4oC but
without frozen. All water samples were handled under chain of custody protocols
and relinquished to the laboratory representatives at locations specified by
the laboratory.
Quality Control Measures
for Sample Testing
5.34
The samples testing and following QC programmes
were performed by WELLAB Ltd. for
every batch of 20 samples:
·
One
method blank; and
·
One
set of QC sample.
5.35
All additional water quality monitoring
was conducted as scheduled in the reporting month. The water quality monitoring
schedule for this reporting month is shown in Appendix D.
5.36
The monitoring results and graphical
presentation of additional water quality monitoring are shown in Appendix G.
5.37
The
summary of exceedance record in the reporting month is shown in Appendix O and summarised
in the Table 5.6.
Table 5.6 Summary
of Water Quality Exceedances
|
Exceedance Level |
DO |
Turbidity |
SS |
Arsenic |
Total
number of Non-project Related Exceedances |
Total
number of project Related Exceedances |
|
|
SYR-IS1 |
Action
Level |
0 |
0 |
0 |
0 |
0 |
0 |
|
Limit Level |
1 |
1 |
0 |
0 |
2 |
0 |
|
|
NTR-IS1 |
Action
Level |
0 |
1 |
0 |
N/A |
1 |
0 |
|
Limit Level |
1 |
0 |
0 |
1 |
0 |
||
|
SHST-IS2 |
Action
Level |
0 |
0 |
0 |
0 |
0 |
|
|
Limit Level |
1 |
0 |
0 |
1 |
0 |
||
|
MWR-IS3 |
Action
Level |
0 |
0 |
0 |
0 |
0 |
|
|
Limit Level |
2 |
1 |
0 |
3 |
0 |
||
|
Total |
Action
Level |
0 |
1 |
0 |
0 |
1 |
0 |
|
Limit Level |
5 |
2 |
0 |
0 |
7 |
0 |
* Exceedances
record date: 13/11/2024, 20/11/2024
Five (5) Limit Level for DO, One (1) Action Level and
Two (2) Limit Level for turbidity of impact water quality monitoring were
recorded. Exceedances were recorded on 13 and 20 November 2024. After
investigation, all the exceedance at SYR-IS1, NTR-IS1, SHST-IS2 and MWR-IS3 were
considered caused by other external factors rather than the contract works due
to the following reasons:
1.
No pollution discharge was observed from land-based site area;
2.
Water mitigation measures at the nearby construction sites were observed
implemented properly; and
3.
No direct
evidence showed that the exceedance was contributed by the works activities by
ND/2019/02 as no related active construction works were undertaken on 20
November 2024 at the concerned location of the construction site.
5.38
Should
any non-compliance of the criteria occur, actions
in accordance with the Event/Action Plan in Appendix N shall be carried out.