A picture containing logo

Description automatically generated

 

                                                                                    

Graphical user interface, text, application

Description automatically generated

 

 

 

Contents

Executive Summary 

1       Introduction

1.1      Background

1.2      Purpose of the Report

1.3      Structure of the Report

2       Air Quality

2.1      Monitoring Requirement

2.2      Monitoring Locations

2.3      Monitoring Parameters, Frequency and Duration

2.4      Monitoring Equipment

2.5      Monitoring Methodology

2.6      Weather Data

2.7      Results and Observations

2.8      Action and Limit Levels

2.9      Event and Action Plan

3       Noise

3.1      Monitoring Requirement

3.2      Monitoring Locations

3.3      Monitoring Parameters, Frequency and Duration

3.4      Monitoring Equipment

3.5      Monitoring Methodology

3.5.1         Monitoring Procedure 

3.5.2         Maintenance and Calibration

3.6      Results and Observations

3.7      Action and Limit Levels 

3.8      Event and Action Plan

4       Water Quality

4.1      Monitoring Requirement

4.2      Monitoring Locations

4.3      Monitoring Parameters, Frequency and Schedule

4.4      Monitoring Methodology

4.4.1         Operating/Analytical Procedures

4.4.2         Laboratory Analytical Methods

4.5      Quality Assurance (QA) / Quality Control (QC) Requirements

4.5.1         Calibration of In-situ Instruments  

4.5.2         Sampling Management and Supervision

4.5.3         Quality Control Measures for Sample Testing

4.6      Baseline Monitoring Results

4.7      Results Discussion

4.7.1         Tung Chung Stream (West) Stations

4.7.2         Tung Chung Stream (East) Stations

4.7.3         Tung Chung Bay Station

4.7.4         Implications on Action and Limit Levels

4.8      Action and Limit Levels

4.9      Event and Action Plan

5       Ecology

5.1      Background

5.2      Setup of the Pre-construction Baseline Monitoring

5.2.1         Monitoring Locations

5.2.2         Monitoring Period and Frequency

5.2.3         Monitoring Requirement 

5.2.4         Monitoring Methodology 

5.2.5         Monitoring Result

5.3      Action and Limit Levels and Event and Action Plan 

5.4      References

6       Landscape and Visual

6.1      Monitoring Requirement  

6.2      Monitoring Methodology

6.3      Monitoring Results

6.3.1         Landscape Resources (LRs)

6.3.2         Landscape Character Areas (LCAs)

6.3.3         Visual Sensitive Receivers (VSRs) 

6.3.4         Existing Trees

7       Conclusion  

Appendices

A.      Air Quality Baseline Monitoring - Technical Information

B.      Noise Baseline Monitoring - Technical Information

C.      Water Quality Baseline Monitoring - Technical Information

D.      Ecological Baseline Monitoring - Technical Information

E.      Landscape and Visual Baseline Monitoring - Technical Information

 

Tables

Table 2.1: Baseline Air Quality Monitoring Stations  5

Table 2.2: Air Quality Monitoring Parameters, Frequency and Period  5

Table 2.3: 1-hour TSP Monitoring Equipment 5

Table 2.4: Summary of Baseline 1-hour TSP Monitoring Results  7

Table 2.5: Derivation of Action and Limit Levels for Air Quality  7

Table 2.6: Action and Limit Levels for 1-hour TSP  7

Table 2.7: Event and Action Plan for Construction Air Quality (Action Level) 8

Table 2.8: Event and Action Plan for Construction Air Quality (Limit Level) 9

Table 3.1: Baseline Noise Monitoring Stations  10

Table 3.2: Noise Monitoring Parameters, Frequency and Period  10

Table 3.3: Noise Monitoring Equipment 11

Table 3.4: Summary of Baseline Noise Monitoring Results - Normal Weekday Daytime (0700-1900 hrs) 12

Table 3.5: Summary of Baseline Noise Monitoring Results - Evening on Normal Weekday (1900-2300 hrs) and Sunday/Public Holiday (0700-2300 hrs) 12

Table 3.6: Summary of Baseline Noise Monitoring Results - Night-time (2300-0700 hrs) 13

Table 3.7: Action and Limit Levels for Construction Noise  13

Table 3.8: Event and Action Plan for Construction Noise  14

Table 4.1: Baseline Water Quality Monitoring Stations  15

Table 4.2: Water Quality Monitoring Parameters and Frequency  16

Table 4.3: Water Quality Monitoring Equipment 16

Table 4.4: Methods for Laboratory Analysis for Water Samples  17

Table 4.5: Updated Criteria for Action and Limit Levels for Impact Water Quality Monitoring  21

Table 4.6: Calculated Action and Limit Levels for Impact Water Quality Monitoring  21

Table 4.7: Event and Action Plan for Construction Water Quality  23

Table 5.1: Baseline Ecological and Water Quality Monitoring Stations  26

Table 5.2: Baseline Ecological and Water Quality Monitoring Schedule  26

Table 5.3: Water Quality Monitoring Parameters and Testing Methods  28

Table 5.4: Physical Environment of the Monitoring Stations  29

Table 5.5: Cumulative Record of Aquatic Invertebrate Species  30

Table 5.6: Cumulative Record of Fish Species  31

Table 5.7: Occurrence Frequency of Aquatic Invertebrate Species Recorded  32

Table 5.8: Occurrence Frequency of Fish Species Recorded  33

Table 5.9: Action and Limit Levels for Ecological Monitoring during Construction Phase  36

Table 5.10: Average Number of Macroinvertebrate Species at Wet Season (April to October) & Dry Season (November to March) at the Aquatic Fauna Monitoring Stations  36

Table 5.11: Average Number of Fish Species at Wet Season (April to October) & Dry Season (November to March) at the Aquatic Fauna Monitoring Stations  36

Table 5.12: Event and Action Plan for Action and Limit Level Exceedance in Aquatic Fauna  37

Table 6.1: Summary of Proposed Tree Treatment 42

Table 6.2: Proposed Tree Treatment for the Trees of Particular Interest 43

 

No table of figures entries found.

 

Executive Summary

Mott MacDonald Hong Kong Limited (MMHK) was appointed by the Civil Engineering and Development Department (CEDD) under "Agreement No. CE 64/2020 (EP) - Environmental Team for Tung Chung New Town Extension (West) - Design and Construction" (hereinafter referred to as "the Assignment") to provide Environmental Team (ET) services regarding the Tung Chung New Town Extension (TCNTE) development in Tung Chung West (hereafter referred to as "the Project").

This Baseline Monitoring Report presents the monitoring works conducted in the period from July 2021 to September 2021 and aims to establish the baseline levels of air quality (dust) and noise, water quality, ecology, and landscape and visual in the vicinity of the Project area, in accordance with the EP Condition 3.4 of the corresponding Environmental Permit (EP) (EP No. EP-519/2016) and Section 16.2 of the Updated Environmental Monitoring and Audit (EM&A) Manual for the TCNTE development dated May 2018 (hereinafter referred to as the "Updated EM&A Manual").

Baseline Air Quality Monitoring

Baseline air quality (dust) monitoring (1-hour TSP) was carried out at the two designated monitoring locations (DM-5 and DM-6) from 9 to 17 July 2021 and from 21 to 25 July 2021. Monitoring was suspended on 18, 19 and 20 July 2021 due to a tropical cyclone. Overall, the baseline air quality results are considered representative to the ambient air quality of the Project and were used to establish the Action and Limit Levels for air quality (1-hour TSP levels).

Baseline Noise Monitoring

Baseline noise monitoring was carried out at the five designated monitoring locations (NMS-CA-5, NMS-CA-6, NMS-CA-7, NMS-CA-8 and NMS-CA-9). Monitoring was conducted at NMS-CA-5 and NMS-CA-6 from 10 to 17 July 2021 and from 20 to 27 July 2021, at NMS-CA-7 from 16 to 18 August 2021 and from 19 to 31 August 2021, and at NMS-CA-8 and NMS-CA-9 from 9 to 17 July 2021 and from 20 to 26 July 2021. Due to a tropical cyclone, monitoring at NMS-CA-5, NMS-CA-6, NMS-CA-8 and NMS-CA-9 was suspended on 17 July 2021 at 19:00 and resumed on 20 July 2021 at 23:00. Also, due to rainstorm, monitoring at NMS-CA-7 was suspended on 18 August 2021 at 23:00 and resumed on 19 August 2021 at 23:00.

During the baseline monitoring period, the major noise sources identified were:

    dog barking and bird chirping at NMS-CA-5;

    traffic noise, dog barking and bird chirping at NMS-CA-6;

    traffic noise, dog barking, bird chirping and excavator operating nearby at NMS-CA-7; and

    traffic noise at NMS-CA-8 and NMS-CA-9.

In general, the measured noise data at the five measured monitoring locations is considered representative of the baseline conditions for the Project.

Baseline Water Quality Monitoring

Baseline water quality monitoring was conducted at the seven designated monitoring stations presented in Table 2.5 of the Baseline Monitoring Proposal for Construction Phase Water Quality (TCW-WQM1, TCW-WQM2, TCW-WQM3A, TCW-WQM4, TCW-WQM5A, TCW-WQM6 and TCW-WQM7). Monitoring was conducted from 9 August 2021 to 3 September 2021. No observable pollution source was recorded at the monitoring stations, however the baseline monitoring results are found to be inadequate to represent the natural variations in ambient water quality levels. Therefore, it was considered prudent to incorporate additional baseline data to establish the Action and Limit Levels.

For supplementing Tung Chung Stream (West) (i.e. TCW-WQM2, TCW-WQM4 and TCW-WQM6) stations, and Tung Chung Stream (East) (i.e. TCW-WQM3A, TCW-WQM5A and TCW-WQM7) stations, EPD's routine river water quality monitoring at Tung Chung River (TC1 at Tung Chung Stream West and TC2 at Tung Chung Stream East respectively) was used to supplement the baseline data for SS and Turbidity. For TCW-WQM1, no EPD routine marine water quality monitoring station at Tung Chung Bay is available, hence a supplementary 4-week baseline monitoring was carried out at TCW-WQM1 in October to November 2021 to extend the baseline monitoring dataset for deriving the Action and Limit Levels at TCW-WQM1.

Notwithstanding the above, the baseline conditions will be reviewed regularly and updated as appropriate, to demonstrate the continued suitability of the impact and control monitoring.

Baseline Ecological Monitoring

Baseline ecological and water quality monitoring was conducted from 21 August 2020 to 14 July 2021 on a monthly basis at four (4) stations in River Park area (RP1, RP2, RP3, RP4) for 12 months and three (3) stations in other Public Works area (PW1, PW2, PW3) for 6 months covering wet season, as presented in Section 2.2 of the Detailed Ecological and Water Quality Monitoring Plan prepared by the Environmental Team of Tung Chung New Town Extension (East) ("TCE ET").

As presented in the Ecological and Water Quality Final Monitoring Report prepared by the TCE ET, for ecological monitoring, a total of 20 aquatic invertebrate and 28 fish species were recorded, among which one (1) aquatic invertebrate and three (3) fish species of conservation significance were recorded. For water quality monitoring, monitoring results are generally similar across the stations, except two (2) of which are located at the proximity of the estuary, showing higher levels in certain parameters due to the estuarine environment and tidal influence. Action and Limit Levels were established for taxa diversity, i.e. number of species, of fish and macroinvertebrate based on the baseline monitoring results. An Event and Action Plan was also proposed for exceedance of the Action and Limit Levels. 

Baseline Landscape and Visual Monitoring

Baseline landscape and visual monitoring was carried out in July 2021 to review the identified Landscape Resources, Landscape Character Areas and Visually Sensitive Receivers in the approved EIA report.

In general, the landscape and visual baseline conditions remain similar as that identified in the approved EIA report, except Ongoing Major Comprehensive Urban Development Landscape (LCA7b) identified at the EIA stage was recorded to have changed into Residential Urban Landscape (LCA13).

In addition, the distribution of tree groups within the Works Area remained unchanged since the EIA stage. No newly planted tree groups were identified within the Works Area, while no tree groups identified at the EIA stage have been removed.

Overall, there is no major change in the landscape and visual baseline conditions comparing to those during the EIA stage. Therefore, no additional landscape and visual mitigation measures other than those recommended in the approved EIA Report are required.

 

 

1        Introduction

1.1        Background

The Civil Engineering and Development Department (CEDD) and the Planning Department (PlanD) jointly commissioned Agreement No. CE 32/2011 (CE) "Planning and Engineering Study on the Remaining Development in Tung Chung" (hereafter referred to as the "P&E Study") in 2012, which aims at identifying development potentials and opportunities to expand Tung Chung New Town into a distinct community to meet housing, social, economic, environmental, and local needs. Under the P&E Study, various planning, engineering, and environmental studies (including a statutory Environmental Impact Assessment (EIA) Study) were carried out to formulate a development scheme, namely Tung Chung New Town Extension (TCNTE), to expand the existing Tung Chung New Town to the east and the west, i.e. Tung Chung East (TCE) and Tung Chung West (TCW) respectively.

The scope of the TCNTE development in TCW (hereafter referred to as "the Project") includes site formation and engineering infrastructure works for the developments of TCW, provision of a river park and revitalisation of an existing channelized section of Tung Chung Stream.

The P&E Study and specific works components in the TCNTE development plan are "Designated Projects" under Item 1 of Schedule 3 and numerous Items of Schedule 2, respectively, of the Environmental Impact Assessment Ordinance (EIAO). The EIA Report (Register No. AEIAR-196/2016) for the entire TCNTE development was approved with conditions on 8 April 2016 and the corresponding Environmental Permit (EP) (No. EP-519/2016) was issued on 9 August 2016.

Mott MacDonald Hong Kong Limited (MMHK) was appointed by CEDD under "Agreement No. CE 64/2020 (EP) - Environmental Team for Tung Chung New Town Extension (West) - Design and Construction" (hereinafter referred to as "the Assignment") to provide Environmental Team (ET) services regarding the Project. This Assignment commenced on 27 May 2021 and is scheduled to be completed in 129 months.

1.2        Purpose of the Report

This Baseline Monitoring Report aims to present the baseline levels of air quality (dust) and noise, water quality, ecology, and landscape and visual in the vicinity of the Project area prior to the commencement of construction works of the Project, in accordance with EP Condition 3.4 of the corresponding Environmental Permit (EP) (EP No. EP-519/2016) and Section 16.2 of the Updated Environmental Monitoring and Audit (EM&A) Manual of the TCNTE development (hereinafter referred to as the "Updated EM&A Manual").

This report summarizes the schedules, locations, equipment, methodology, results and observations made during the baseline monitoring and establishes the Action and Limit Levels for the subsequent impact monitoring during the construction stage.

1.3        Structure of the Report

The structure of the report is as follows:

    Section 1 -    Introduction, background, project description, purpose, and structure of the report.

    Section 2 -    Air Quality - presents the methodology and findings of the baseline air quality monitoring.

    Section 3 -    Noise - presents the methodology and findings of the baseline noise monitoring.

    Section 4 -    Water Quality - presents the methodology and findings of the water quality monitoring.

    Section 5 -    Ecology - presents the methodology and findings of the baseline ecological monitoring.

    Section 6 -    Landscape and Visual - presents the methodology and findings of the baseline landscape and visual monitoring.

    Section 7 -    Conclusions


 

2        Air Quality

2.1        Monitoring Requirement

According to the requirements in the Updated EM&A Manual, baseline air quality monitoring shall be carried out at designated monitoring locations for at least 14 consecutive days prior to the commencement of the construction works to obtain 1-hour Total Suspended Particulate (TSP) sample. The selected baseline monitoring stations should reflect baseline conditions at the impact stations. One-hour sampling should be done at least 3 times per day while the highest dust impact is expected. Further details of the baseline air quality monitoring are presented in the following sections.

2.2        Monitoring Locations

According to the Updated EM&A Manual, a total of six air quality monitoring stations are identified for the impact monitoring locations.  Of these six air quality monitoring stations, two are located in the TCNTE possible development area (PDA) at Tung Chung West and are covered by this report. Locations of the baseline air quality monitoring stations covered in this report are summarised in Table 2.1 and shown in Appendix A1. Photographs of the monitoring equipment set up at baseline monitoring stations are given in Appendix A2.

Table 2.1: Baseline Air Quality Monitoring Stations

Monitoring Station

Location

Status

DM-5

Lung Tseung Tau

Existing Air Sensitive Receiver

DM-6

Mok Ka

Existing Air Sensitive Receiver

2.3        Monitoring Parameters, Frequency and Duration

Table 2.2 summarizes the monitoring parameters, frequency, duration and monitoring period of the baseline 1-hour TSP monitoring. The baseline air quality monitoring schedule is provided in Appendix A3.

Table 2.2: Air Quality Monitoring Parameters, Frequency and Period

Monitoring Station

Parameter

Frequency

Duration

Monitoring Period

DM-5

1-hour Total Suspended Particulates (TSP)

3 times per day

14 consecutive days

9 to 17 July 2021, 21 to 25 July 2021

DM-6

9 to 17 July 2021, 21 to 25 July 2021

Remark: Due to tropical cyclone, baseline air quality monitoring was suspended on 18, 19 and 20 July 2021 and resumed on 21 July 2021.

2.4        Monitoring Equipment

Portable direct reading dust meter was used to carry out the 1-hour TSP monitoring. Table 2.3 summarizes the equipment used in the baseline air quality monitoring. Copies of the calibration certificates for the portable dust meters are attached in Appendix A4.

Table 2.3: 1-hour TSP Monitoring Equipment

Monitoring Station

Equipment

Model

DM-5

Portable direct reading dust meter

SIBATA LD-3B (serial no. 276017)

DM-6

Portable direct reading dust meter

SIBATA LD-3B (serial no. 2Z6239)

2.5        Monitoring Methodology

1-hour TSP Monitoring

Field Monitoring

The measuring procedures of the 1-hour dust meter are in accordance with the Manufacturer's Instruction Manual as follows:

    Turn the power on.

    Close the air collecting opening cover.

    Push the "TIME SETTING" switch to [BG].

    Push "START/STOP" switch to perform background measurement for 6 seconds.

    Turn the knob at SENSI ADJ position to insert the light scattering plate.

    Leave the equipment for 1 minute upon "SPAN CHECK" is indicated in the display.

    Push "START/STOP" switch to perform automatic sensitivity adjustment. This measurement takes 1 minute.

    Pull out the knob and return it to MEASURE position.

    Setting time period of 1 hour for the 1-hour TSP measurement.

    Push "START/STOP" to start the 1-hour TSP measurement.

    Regular checking of the time period setting to ensure monitoring time of 1 hour.

Maintenance and Calibration (QA/QC Procedure)

    The 1-hour dust meter would be checked at 3-month intervals and calibrated at 1-year intervals throughout all stages of the air quality monitoring.

    Calibration records for direct reading dust meters are given in Appendix A4.

2.6        Weather Data

Wind data collected from the Hong Kong Observatory's (HKO) Chek Lap Kok (CLK) wind station was used for the air quality monitoring and is presented in Appendix A5. It is considered that the wind data obtained at the existing CLK wind station is representative of the Project area and could be used for undertaking the baseline and construction phase air quality monitoring programme for the Project.

The proposed use of the existing wind data collected from CLK wind station for wind data collection instead of setting up wind monitoring equipment near the monitoring stations was proposed by the ET Leader and agreed by IEC, in accordance with the requirements stated in Section 5.5 of the Updated EM&A Manual.

2.7        Results and Observations

The baseline air quality monitoring has been carried out at the two designated monitoring locations, namely DM-5 and DM-6, from 9 to 17 July 2021 and from 21 to 25 July 2021, for a total of 14 days. Due to tropical cyclone, baseline air quality monitoring was suspended on 18, 19 and 20 July 2021 and resumed on 21 July 2021.

The detection limit of the portable dust meter is 1 μg/m3. All portable dust meters were calibrated before conducting baseline air quality monitoring as quality assurance measure. The digital dust meters used produced a correlation coefficient of 0.9963 and 0.9954, which are higher than the acceptable value of 0.8. Calibration certificates of the portable dust meters are provided in Appendix A4.

The weather was generally sunny or cloudy during the baseline monitoring period. No major events were identified which may have influenced or affected the results of baseline monitoring. The detailed 1-hour TSP monitoring results are summarised in Table 2.4. Graphical plots of the monitoring results are shown in Appendix A6.

Table 2.4: Summary of Baseline 1-hour TSP Monitoring Results

Monitoring Station

Average 1-hour TSP (μg/m3)

1-hour TSP Range (μg/m3)

DM-5

24

10 - 60

DM-6

16

6 - 30

2.8        Action and Limit Levels

The Action and Limit Levels for 1-hour TSP have been set in accordance with the derivation criteria specified in the Updated EM&A Manual and are reproduced in Table 2.5.

Table 2.5: Derivation of Action and Limit Levels for Air Quality

Parameter

Action Level (μg/m3)

Limit Level (μg/m3)

1-hour TSP Level

   For baseline level - 384 μg/m3,

Action level = (Baseline level * 1.3 + Limit level)/2;

   For baseline level > 384 μg/m3,

Action level = Limit level

500

Following the abovementioned criteria, the Action and Limit Levels of 1-hour TSP for the monitoring stations were derived and are presented in Table 2.6.

Table 2.6: Action and Limit Levels for 1-hour TSP

Monitoring Station

Action Level (μg/m3)

Limit Level (μg/m3)

DM-5

266

500

DM-6

260

500

2.9        Event and Action Plan

Should non-compliance of the air quality criteria occur, actions in accordance with the Event and Action Plan in Table 2.7 and Table 2.8 shall be carried out.


Table 2.7: Event and Action Plan for Construction Air Quality (Action Level)

Event

Action

ET

IEC

ER

Contractor

Action Level

 

 

 

 

Exceedance for one sample

1. Identify source, investigate the causes of exceedance and propose remedial measures;

2. Inform IEC and ER;

3. Repeat measurement to confirm finding;

4. Increase monitoring frequency to daily.

1. Check monitoring data submitted by ET;

2. Check Contractor's working method.

1. Notify Contractor.

1. Rectify any unacceptable practice;

2. Amend working methods if appropriate.

Exceedance for two or more consecutive samples

1. Identify source;

2. Inform IEC and ER;

3. Advise the ER on the effectiveness of the proposed remedial measures;

4. Repeat measurements to confirm findings;

5. Increase monitoring frequency to daily;

6. Discuss with IEC and Contractor on remedial actions required;

7. If exceedance continues, arrange meeting with IEC and ER;

8. If exceedance stops, cease additional monitoring.

1. Check monitoring data submitted by ET;

2. Check Contractor's working method;

3. Discuss with ET and Contractor on possible remedial measures;

4. Advise the ET on the effectiveness of the proposed remedial measures;

5. Supervise Implementation of remedial measures.

1. Confirm receipt of notification of failure in writing;

2. Notify Contractor;

3. Ensure remedial measures properly implemented.

1. Submit proposals for remedial to ER within 3 working days of notification;

2. Implement the agreed proposals;

3. Amend proposal if appropriate.

 

Table 2.8: Event and Action Plan for Construction Air Quality (Limit Level)

Event

Action

ET

IEC

ER

Contractor

Limit Level

 

 

 

 

Exceedance for one sample

1. Identify source, investigate the causes of exceedance and propose remedial measures;

2. Inform ER, Contractor and EPD;

3. Repeat measurement to confirm finding;

4. Increase monitoring frequency to daily;

5. Assess effectiveness of Contractor's remedial actions and keep IEC, EPD and ER informed of the results.

1. Check monitoring data submitted by ET;

2. Check Contractor's working method;

3. Discuss with ET and Contractor on possible remedial measures;

4. Advise the ER on the effectiveness of the proposed remedial measures;

5. Supervise implementation of remedial measures.

1. Confirm receipt of notification of failure in writing;

2. Notify Contractor;

3. Ensure remedial measures properly implemented..

1. Take immediate action to avoid further exceedance;

2. Submit proposals for remedial actions to IEC within 3 working days of notification;

3. Implement the agreed proposals;

4. Amend proposal if appropriate.

Exceedance for two or more consecutive samples

1. Notify IEC, ER, Contractor and EPD;

2. Identify source;

3. Repeat measurement to confirm findings;

4. Increase monitoring frequency to daily;

5. Carry out analysis of Contractor's working procedures to determine possible mitigation to be implemented;

6. Arrange meeting with IEC and ER to discuss the remedial actions to be taken;

7. Assess effectiveness of Contractor's remedial actions and keep IEC, EPD and ER informed of the results;

8. If exceedance stops, cease additional monitoring.

1. Discuss amongst ER, ET, and Contractor on the potential remedial actions;

2. Review Contractor's remedial actions whenever necessary to assure their effectiveness and advise the ER accordingly;

3. Supervise the implementation of remedial measures.

1. Confirm receipt of notification of failure in writing;

2. Notify Contractor;

3. In consultation with the IEC, agree with the Contractor on the remedial measures to be implemented;

4. Ensure remedial measures properly implemented;

5. If exceedance continues, consider what portion of the work is responsible and instruct the Contractor to stop that portion of work until the exceedance is abated.

1. Take immediate action to avoid further exceedance;

2. Submit proposals for remedial actions to IEC within 3 working days of notification;

3. Implement the agreed proposals;

4. Resubmit proposals if problem still not under control;

5. Stop the relevant portion of works as determined by the ER until the exceedance is abated.

 


3        Noise

3.1        Monitoring Requirement

According to the requirements in the Updated EM&A Manual, baseline noise monitoring shall be carried out prior to the commencement of the construction works. Continuous baseline noise monitoring for the A-weighted levels Leq, L10 and L90 shall be carried out daily for at least two weeks in a sample period interval of: 30 minutes between 0700 and 1900 on normal weekdays; and 5 minutes between 1900 and 0700 daily, and between 0700 and 1900 on Sundays/public holidays. Further details of the baseline noise monitoring are presented in the following sections.

3.2        Monitoring Locations

According to the Updated EM&A Manual, a total of nine noise monitoring stations are identified for the impact monitoring locations. Of these nine noise monitoring stations, five are located in the possible development area (PDA) at Tung Chung West and are covered by this report. Locations of the noise monitoring stations in the Updated EM&A Manual and this report are listed in Table 3.1 and shown in Appendix B1. Photographs of the monitoring equipment set up at baseline monitoring stations are given in Appendix B2.

Table 3.1: Baseline Noise Monitoring Stations

Monitoring Station

Location

Type of Measurement

NMS-CA-5

Village house in Ma Wan Chung (G/F)

Free field^

NMS-CA-6

Village house in Shek Mun Kap (G/F)

Free field^

NMS-CA-7

YMCA of Hong Kong Christian College (Roof Floor)

Façade

NMS-CA-8#

Caritas Charles Vath College (Roof Floor)

Façade

NMS-CA-9#,*

Hong Chi Shiu Pong Morninghope School (Roof Floor)

Façade

Remark:  #  Prior to commencement of baseline monitoring, both school sites containing NMS-CA-8 and NMA-CA-9 were jointly visited by ET and IEC. It was confirmed that both original locations proposed in the Updated EM&A Manual were found to be too close to noise-emitting operating plant on each school roof floor, such as air-conditioner vents. These were relocated slightly to optimum locations on the same floors away from these infrastructures and duly presented in the "Baseline Monitoring Proposal for Construction Phase (Air Quality and Noise)", which was endorsed by IEC.

* NMS-CA-9, which was described as "possible school development near Tung Chung Area 39" in the Updated EM&A Manual, was subsequently confirmed as "Hong Chi Shiu Pong Morninghope School" prior to commencement of baseline monitoring.

                ^  For Free Field measurement, +3dB(A) should be added to the measured results.

3.3        Monitoring Parameters, Frequency and Duration

Table 3.2 summarizes the monitoring parameters, frequency, duration and periods of the baseline noise monitoring. The baseline noise monitoring schedule is provided in Appendix B3.

Table 3.2: Noise Monitoring Parameters, Frequency and Period

Monitoring Station

Parameter

Frequency

Duration

Monitoring Periods

NMS-CA-5

Leq(5 mins),

L10(5 mins),

L90(5 mins)

Daily

14 days

10 to 17 July 2021, 20 to 27 July 2021

NMS-CA-6

10 to 17 July 2021, 20 to 27 July 2021

NMS-CA-7

16 to 18 August 2021, 19 to 31 August 2021

NMS-CA-8

9 to 17 July 2021, 20 to 26 July 2021

NMS-CA-9

9 to 17 July 2021, 20 to 26 July 2021

Remark: Due to tropical cyclone, baseline noise monitoring at NMS-CA-5, NMS-CA-6, NMS-CA-8 and NMS-CA-9 was suspended on 17 July 2021 at 19:00 and resumed on 20 July 2021 at 23:00. Also, due to rainstorm, baseline noise monitoring at NMS-CA-7 was suspended on 18 August 2021 at 23:00 and resumed on 19 August 2021 at 23:00.

3.4        Monitoring Equipment

Integrating Sound Level Meters were used to conduct baseline noise monitoring.  They were the Type 1 sound level meter capable of giving a continuous readout of the noise level readings including equivalent continuous sound pressure level (LAeq) and percentile sound pressure level (Lx). They complied with International Electrotechnical Commission Publications 651:1979 (Type 1) and 804:1985 (Type 1). Table 3.3 summarizes the equipment used in the baseline noise monitoring. Copies of the calibration certificates for the sound level meters and acoustical calibrator are attached in Appendix B4.

Table 3.3: Noise Monitoring Equipment

Monitoring Station

Equipment & Model

 

Integrating Sound Level Meter

Acoustical Calibrator

NMS-CA-5

Rion NL-52 (serial no. 00175561)

Larson Davis CAL200 (serial no. 16172)

NMS-CA-6

Rion NL-52 (serial no. 00643039)

Larson Davis CAL200 (serial no. 16172)

NMS-CA-7

Rion NL-52 (serial no. 00131628)

Larson Davis CAL200 (serial no. 10227)

NMS-CA-8

Rion NL-52 (serial no. 00710259)

Larson Davis CAL200 (serial no. 16172)

NMS-CA-9

Rion NL-52 (serial no. 00131628)

Larson Davis CAL200 (serial no. 16172)

3.5        Monitoring Methodology

3.5.1         Monitoring Procedure

The noise monitoring was undertaken using the following procedure:  

a.   The sound level meter was set at least 1.2 m above the ground for free-field measurements at monitoring stations NMS-CA-5 and NMS-CA-6. A correction of +3 dB(A) has been made for the free field measurements.

b.   Façade measurements were made at the monitoring stations NMS-CA-7, NMS-CA-8 and NMS-CA-9.

c.   The battery condition was checked to ensure the correct functioning of the meters.

d.   Parameters such as frequency weighting, the time weighting and the measurement time were set as follows:

i.            frequency weighting: A

ii.           time weighting: Fast

iii.          time measurement: 5-minutes for Leq, L10 and L90, with the calculation of the Leq(30mins) noise levels for each 30-minute interval during the non-restricted hours (i.e. 0700 - 1900 hours on normal weekdays) calculated after the measurements by logarithmic average of six Leq(5min) data.

e.   Prior to and after each noise measurement, the meter was calibrated using the acoustic calibrator for 94dB(A) at 1000 Hz.  If the difference in the calibration level before and after measurement was more than 1 dB(A), the measurement would be considered invalid and repeat of noise measurement would be required after re-calibration or repair of the equipment.

f.    During the monitoring period, the Leq, L10 and L90 were recorded.  In addition, site conditions and noise sources were recorded when the equipment were checked and inspected every 2-3 days.

g.   All the monitoring data stored in the sound level meter system were downloaded through computer software, and all the data was checked and reviewed on computer.

3.5.2         Maintenance and Calibration

The maintenance and calibration procedures are summarised below:

a.   The microphone head of the sound level meter was cleaned with soft cloth at regular intervals.

b.   The meter and calibrator were sent to the supplier or HOKLAS laboratory to check and calibrate at yearly intervals.

c.   Calibration certificates of the sound level meters and acoustic calibrator are provided in Appendix B4.

3.6        Results and Observations

The noise monitoring results are summarised in Table 3.4 to Table 3.6. Detailed noise monitoring results are presented in Appendix B5. In accordance with Section 6.5.1 of the Updated EM&A Manual, a correction of +3 dB(A) was made to the free field measurements at NMS-CA-5 and NMS-CA-6.

Table 3.4: Summary of Baseline Noise Monitoring Results - Normal Weekday Daytime (0700-1900 hrs)

Time Period & Monitoring Station

Leq (30 mins), dB(A)

Normal Weekday Daytime (0700-1900 hrs)

Mean

Range

NMS-CA-5

57.3^

48.9 - 67.8^

NMS-CA-6

58.7^

50.3 - 75.4^

NMS-CA-7

55.0

49.5 - 66.2

NMS-CA-8

56.1

51.3 - 65.7

NMS-CA-9

60.4

56.6 - 68.4

Remark: ^  Includes +3dB(A) correction for Free Field measurement.

Table 3.5: Summary of Baseline Noise Monitoring Results - Evening on Normal Weekday (1900-2300 hrs) and Sunday/Public Holiday (0700-2300 hrs)

Time Period & Monitoring Station

Leq (5 mins), dB(A)

Evening on Normal Weekday (1900-2300 hrs) and Sunday/Public Holiday (0700-2300 hrs)

Mean

Range

NMS-CA-5

53.0^

45.5 - 70.2^

NMS-CA-6

53.2^

46.2 - 74.0^

NMS-CA-7

52.3

44.7 - 68.7

NMS-CA-8

52.9

47.1 - 69.6

NMS-CA-9

58.5

50.7 - 67.5

Remark: ^  Includes +3dB(A) correction for Free Field measurement.

Table 3.6: Summary of Baseline Noise Monitoring Results - Night-time (2300-0700 hrs)

Time Period & Monitoring Station

Leq (5 mins), dB(A)

Night-time (2300-0700 hrs)

Mean

Range

NMS-CA-5

50.8^

45.6 - 87.2^

NMS-CA-6

49.8^

45.0 - 71.7^

NMS-CA-7

49.6

42.6 - 58.6

NMS-CA-8

50.9

45.7 - 68.4

NMS-CA-9

53.4

47.2 - 71.6

Remark: ^  Includes +3dB(A) correction for Free Field measurement.

3.7        Action and Limit Levels

The Action Levels and Limit Levels for construction noise impact monitoring have been defined in accordance with the Updated EM&A Manual and are tabulated in Table 3.7.

Table 3.7: Action and Limit Levels for Construction Noise

Monitoring Station

Time Period

Action Level

Limit Level, Leq (30 mins), dB(A)

NMS-CA-5

NMS-CA-6

0700-1900 hrs on normal weekdays#

When one documented complaint is received

75

NMS-CA-7*

NMS-CA-8*

NMS-CA-9*

70

(65 during school examination periods)

Note:    # If works are to be carried out during restricted hours, the conditions stipulated in the construction noise permit issued by the Noise Control Authority have to be followed.

* Denotes school / educational institution.

3.8        Event and Action Plan

Should non-compliance of the noise criteria occur, actions in accordance with the Event and Action Plan in Table 3.8 shall be carried out.


Table 3.8: Event and Action Plan for Construction Noise

Event

Action

ET

IEC

ER

Contractor

Action Level Exceedance

1.     Notify IEC, ER and Contractor;

2.     Carry out investigation;

3.     Report the results of investigation to the IEC, ER and Contractor;

4.     Discuss with the Contractor and formulate remedial measures;

5.     Increase monitoring frequency to check mitigation effectiveness.

1.     Review the analysed results submitted by the ET;

2.     Review the proposed remedial measures by the Contractor and advise the ER accordingly;

3.     Supervise the implementation of remedial measures.

1.     Confirm receipt of notification of failure in writing;

2.     Notify Contractor;

3.     Require Contractor to propose remedial measures for the analysed noise problem;

4.     Ensure remedial measures are properly implemented

1.     Submit noise mitigation proposals to IEC and ER;

2.     Implement noise mitigation proposals.

Limit Level Exceedance

1.     Identify source;

2.     Inform IEC, ER, EPD and Contractor;

3.     Repeat measurements to confirm findings;

4.     Increase monitoring frequency;

5.     Carry out analysis of Contractor's working procedures to determine possible mitigation to be implemented;

6.     Inform IEC, ER and EPD the causes and actions taken for the exceedances;

7.     Assess effectiveness of Contractor's remedial actions and keep IEC, EPD and ER informed of the results;

8.     If exceedance stops, cease additional monitoring.

1.     Discuss amongst ER, ET, and Contractor on the potential remedial actions;

2.     Review Contractors remedial actions whenever necessary to assure their effectiveness and advise the ER accordingly;

3.     Supervise the implementation of remedial measures.

1.     Confirm receipt of notification of failure in writing;

2.     Notify Contractor;

3.     Require Contractor to propose remedial measures for the analysed noise problem;

4.     Ensure remedial measures properly implemented;

5.     If exceedance continues, consider what portion of the work is responsible and instruct the Contractor to stop that portion of work until the exceedance is abated.

1.     Take immediate action to avoid further exceedance;

2.     Submit proposals for remedial actions to IEC within 3 working days of notification;

3.     Implement the agreed proposals;

4.     Resubmit proposals if problem still not under control;

5.     Stop the relevant portion of works as determined by the ER until the exceedance is abated.

 


4        Water Quality

 

4.1        Monitoring Requirement

In accordance with the Updated EM&A Manual, the baseline water quality monitoring shall be carried out 3 days per week for at least 4 weeks prior to the commencement of construction works at TCW. The measurements shall be taken at all designated monitoring stations at TCW in accordance with the requirements in the approved Baseline Monitoring Proposal for Water Quality. Further details of the baseline water quality monitoring under this Project are presented in the following sections.

4.2        Monitoring Locations

According to the Updated EM&A Manual, five water quality monitoring stations are identified and located in the possible development area (PDA) at Tung Chung West and are covered by this report. All monitoring locations were checked on site to verify their suitability and accessibility.

Following a review of the monitoring programme including monitoring locations with green groups in June 2021, two new monitoring stations were added (TCW-WQM6 and TCW-WQM7). Also, the original location of TCW-WQM3 was replaced with revised location TCW-WQM3A located upstream of the River Park since the original location will be directly modified and inaccessible during construction works. Furthermore, original location TCW-WQM5 was replaced with revised location TCW-WQM5A (at the nearest safe and practical location) since the original location is presently inaccessible for the purposes of baseline monitoring.

The updated list of locations of the water quality monitoring stations in the approved Baseline Monitoring Proposal for Construction Phase Water Quality are listed in Table 4.1 and shown in Appendix C1. Photographs of the monitoring conducted at the baseline monitoring stations are given in Appendix C2.

Table 4.1: Baseline Water Quality Monitoring Stations

Monitoring Station

Description

Location

 

Easting

Northing

TCW-WQM1

Downstream of Tung Chung Stream

810784

815710

Tung Chung Stream (West)

TCW-WQM2

Middle of Tung Chung Stream (West)

810701

815015

TCW-WQM4

Upstream of Tung Chung Stream (West)

810641

814405

TCW-WQM6(1)

Downstream of Tung Chung Stream (West)

810814

815385

Tung Chung Stream (East)

TCW-WQM3A(2)

Middle of Tung Chung Stream (East) [aka Upstream of River Park]

811080

814965

TCW-WQM5A(3)

Upstream of Tung Chung Stream (East)

811194

811138

814368

814498

TCW-WQM7(1)

Downstream of Tung Chung Stream (East) [aka Downstream of River Park]

810862

815400

Notes:

(1)  TCW-WQM6 and TCW-WQM7 are additional monitoring stations which can monitor the water quality impact associated with construction activities along the Tung Chung Stream (West) and Tung Chung Stream (East) respectively.

(2)  TCW-WQM3A is the proposed relocated TCW-WQM3, which will be upstream of the River Park where there are no direct works on Tung Chung Stream (East). The original TCW-WQM3 location lies within the construction works area for the future River Park, which will be directly modified and inaccessible during construction phase.

(3)  The monitoring location of TCW-WQM5A will be bounded by the coordinates shown, with the exact location depending on the nearest safe accessible and practical location to the original TCW-WQM5.

4.3        Monitoring Parameters, Frequency and Schedule

Table 4.2 summarises the monitoring parameters, monitoring period and frequencies of the water quality monitoring. The baseline water quality monitoring schedule is provided in Appendix C3.

Table 4.2: Water Quality Monitoring Parameters and Frequency

Monitoring Station

Parameters (Units)

Frequency and Replication

TCW-WQM1,

TCW-WQM2,

TCW-WQM3A,

TCW-WQM4,

TCW-WQM5A,

TCW-WQM6

TCW-WQM7

       Dissolved Oxygen (DO) (mg/L and % saturation)

       Temperature (ºC)

       Turbidity (NTU)

       Salinity (ppt)

       pH

       Suspended Solids (SS) (mg/L)

       Conductivity(1) (µS/cm)

Baseline monitoring:

3 days per week, for 4 weeks prior to the commencement of construction work.

Two (2) replicate in-situ measurements and water samples.

Remark: Water depth measurement is not applicable due to very shallow depth of the monitoring locations.

Note:

(1)  Conductivity is an additional reference monitoring parameter adopted at the request of green groups during a review of the baseline monitoring programme in June 2021 as referred in Section 4.2. It is not compulsory as prescribed in the Updated EM&A Manual.

In addition to the parameters presented in Table 4.2, other relevant data were also recorded, including monitoring location, time, approximate water depth (by visual observation), tidal condition (if applicable), weather conditions and any special phenomena or work underway at the Project site.

4.4        Monitoring Methodology

Table 4.3 summarizes the equipment used in the baseline water quality monitoring works. All the monitoring equipment complied with the requirements set out in the Updated EM&A Manual. Copies of the calibration certificates are attached in Appendix C4.

Table 4.3: Water Quality Monitoring Equipment

Equipment

Brand and Model

Quantity

Multifunctional Meter (in-situ measurement of DO, pH, temperature, salinity, turbidity and conductivity)

Horiba U-53

(serial nos. KP23RR5M & LUAVCDWU)

2

4.4.1         Operating/Analytical Procedures

At each sampling location, two consecutive measurements of DO level, DO Saturation, Temperature, Turbidity, Salinity and pH were taken. 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 readings, the reading was discarded and further readings were taken. Two samples were collected at each individual monitoring location for laboratory analysis of SS content. Following collection, water samples for laboratory analysis were stored in high density polythene bottles (1L) with no preservatives added, packed in ice (cooled to 4°C without being frozen) and kept in dark during both on-site temporary storage and shipment to the testing laboratory. The samples were delivered to the laboratory as soon as possible and the laboratory determination works started within 24 hours after collection of the water samples. Sufficient volume of samples was collected to achieve the reporting limit.

4.4.2         Laboratory Analytical Methods

The testing of SS for all stations was conducted by ALS Technichem (HK) Pty Ltd (HOKLAS Registration No. 066). Comprehensive quality assurance and control procedures were in place in order to ensure quality and consistency in results. The testing method and reporting limit are provided in Table 4.4.

Table 4.4: Methods for Laboratory Analysis for Water Samples

Parameter

Analytical Method

Reporting Limit

Suspended Solids (SS)

APHA 17e 2540D

0.5 mg/L

4.5        Quality Assurance (QA) / Quality Control (QC) Requirements

4.5.1         Calibration of In-situ Instruments

All in situ monitoring instruments were checked, calibrated and certified by a laboratory accredited under HOKLAS or other international accreditation scheme before use, and subsequently re-calibrated at three-monthly intervals throughout all stages of the water quality monitoring programme. Responses of sensors and electrodes were checked with certified standard solutions before each daily use. Wet bulb calibration for a DO meter was carried out before measurement at each monitoring event.

For the on-site calibration of field equipment (Multi-parameter Water Quality System), the BS 1427:2009, "Guide to on-site test methods for the analysis of waters" was observed.

Sufficient stocks of spare parts were maintained for replacements when necessary. Backup monitoring equipment was also made available so that monitoring can proceed uninterrupted even when some equipment was under maintenance, calibration, etc.

4.5.2         Sampling Management and Supervision

All sampling bottles were labelled with the sample ID (such as the indication of sampling station), laboratory number and sampling date. Water samples were dispatched to the testing laboratory for analysis as soon as possible after the sampling. All samples were stored in a cool box and kept at less than 4°C 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. The laboratory determination works started within 24 hours after collection of water samples.

4.5.3         Quality Control Measures for Sample Testing

The samples testing was performed by ALS Technichem (HK) Pty Ltd. The following quality control programme was performed by the laboratory for every batch of 20 samples:

    One method blank; and

    One set of quality control (QC) samples (including method QC and sample duplicate).

4.6        Baseline Monitoring Results

The 4-week baseline water quality monitoring was conducted at the six baseline monitoring stations within Tung Chung River (TCW-WQM2, TCW-WQM3A, TCW-WQM4, TCW-WQM5A, TCW-WQM6 and TCW-WQM7), while a 4-week baseline plus supplementary 4-weeks (total 8-weeks) baseline water quality monitoring was conducted at TCW-WQM1 located within Tung Chung Bay (refer to Section 4.7.4). The monitoring results at each monitoring station are shown in Appendix C5.

Graphical presentation of baseline water quality at each monitoring station is presented in Appendix C6 and grouped into the following for ease of reference:

    TCW-WQM2, TCW-WQM4 and TCW-WQM6 for the stream located in the west of Tung Chung Valley (i.e. Tung Chung Stream (West) - see Figures C6-7 to C6-12);

    TCW-WQM3A, TCW-WQM5A and TCW-WQM7 for the stream located in the east of Tung Chung Valley (i.e. Tung Chung Stream (East) - see Figures C6-13 to C6-18);

    TCW-WQM1 (i.e. downstream of both abovementioned West and East streams - see Figures C6-1 to C6-6).

During the baseline monitoring period, no construction works were observed in the vicinity of all monitoring stations. The baseline monitoring results are thus considered representative of the ambient water quality of the Project area during the season.

4.7        Results Discussion

The results for DO, Turbidity and SS were analysed to inform the approach for deriving Action and Limit Levels. As Tung Chung Stream (West) and Tung Chung Stream (East) are not directly hydraulically connected until the point downstream of TCW-WQM6 and TCW-WQM7 (where they converge before flowing out to Tung Chung Bay), it is sensible to consider the water quality results under the following groups:

    Tung Chung Stream (West) stations (i.e. TCW-WQM2, TCW-WQM4 and TCW-WQM6)

    Tung Chung Stream (East) stations (i.e. TCW-WQM3A, TCW-WQM5A and TCW-WQM7)

    Tung Chung Bay station (i.e. TCW-WQM1)

4.7.1         Tung Chung Stream (West) Stations

DO results along this stream ranges from 1.8 mg/L to 5.9 mg/L, with a clear increasing trend in DO concentrations further downstream. The particularly low DO results at upstream (TCW-WQM4 with results ranging from 1.8 mg/L to 3.4 mg/L) appears to be somewhat unusual but may be attributed to an area of relatively stagnant waters which can easily deplete DO.

Results for Turbidity and SS both show very low values except for one monitoring day (1 Sep) which was associated with a rainstorm event. Trend analysis between the control station (TCW-WQM4) and impact stations (TCW-WQM2 and TCW-WQM6) shows that Turbidity values at impact stations are 'best fit' at 1.8188x (~182%) that of the same-day control (see Appendix C7). The generally low absolute values of Turbidity recorded during the baseline monitoring is more likely to give rise to higher percentage differences between the upstream and the mid to downstream sections of Tung Chung Stream (West).

For SS which has very low absolute values (between 0.5 mg/L to 2.2 mg/L excluding the rainstorm event on 1 Sep), the trend shows an even greater difference between control and impact stations (best fit line at 2.4045x or ~240%). This is reflected in the tabulated percentage difference between control and impact stations (see Appendix C7), whereby 18 out of the 24 datasets show a difference greater than the standard 120% of same-day control adopted as Action Level for construction phase impact water quality monitoring.

4.7.2         Tung Chung Stream (East) Stations

DO results along this stream ranges from 3.9 mg/L to 6.5 mg/L, with values typically slightly higher upstream than downstream.

Results for Turbidity and SS show similar low values as those at Tung Chung Stream (West), except for one monitoring day (1 Sep) which was associated with a rainstorm event. Trend analysis between the control station (TCW-WQM5A) and impact stations (TCW-WQM3A and TCW-WQM7) shows that Turbidity values at impact stations are 'best fit' at 1.508x (~151%) that of the same-day control (see Appendix C7). Again, the generally low absolute values of Turbidity recorded during the baseline monitoring is more likely to give rise to higher percentage differences between the upstream and the mid to downstream sections of Tung Chung Stream (East).

For SS which has similarly low absolute values (between 0.6 mg/L to 6.8 mg/L excluding the rainstorm event on 1 Sep), the trend shows an even greater difference between control and impact stations (best fit line at 2.2309x or ~223%). This is reflected in the tabulated percentage difference between control and impact stations (see Appendix C7), whereby 23 out of the 24 datasets show a difference greater than the standard 120% of same-day control adopted as Action Level for construction phase impact water quality monitoring.

4.7.3         Tung Chung Bay Station

DO results at TCW-WQM1 varies from 1.7 mg/L to 8.0 mg/L. Data from the total 8-week monitoring period at this station exhibits a broader range compared to the DO results from Tung Chung Stream (West and East) stations (with 4-week concurrent baseline period) and does not exhibit a notable pattern compared to the other stations, suggesting that the DO at TCW-WQM1 is not entirely dependent on the DO content of flows from Tung Chung Streams.

Turbidity values at this station are notably higher and SS values at this station are slightly higher than at the Tung Chung Stream stations for most of the time, ranging from 3.8 NTU to 38.3 NTU for Turbidity, and 2.1 mg/L to 10.4 mg/L for SS respectively. TCW-WQM1 is affected by both Tung Chung Stream (West and East) stations as well as tidal effects, which may complicate the patterns of Turbidity and SS observed at this station.

4.7.4         Implications on Action and Limit Levels

DO

Action and Limit Levels for DO as specified in the Updated EM&A Manual are based solely on the baseline dataset obtained during the 4-week baseline monitoring period or the WQOs. As identified in Section 4.7.1, the DO results at TCW-WQM4 are unusually low, and inclusion of these results to derive the 5 percentile and 1 percentile Action and Limit Levels would create very low 'permissible' DO levels applied at the midstream and downstream stations (TCW-WQM2 and TCW-WQM6) which is not reflective of the baseline DO levels observed at these locations further downstream. Therefore, it is considered more prudent to exclude the results from TCW-WQM4 in determining the Action and Limit Levels for DO at Tung Chung Stream (West). In addition, while the use of same-day controls is not specified for DO, reference to the DO levels at the upstream control stations are nevertheless recommended during exceedance investigations for DO to facilitate consideration of both natural and anthropogenic factors that may contribute to DO depletion at the impact stations.

Turbidity and SS

As shown in Appendix C7, both TCW-WQM4 and TCW-WQM5A (control stations) exhibit a natural difference in Turbidity and SS to the downstream sections of Tung Chung Stream (West) and Tung Chung Stream (East) that already exceeds the standard 120% Action Level and 130% Limit Level threshold for a significant amount of time (for Turbidity) and a vast majority of the time (for SS). What this means is that under normal conditions, the trigger for Action and Limit Level exceedance would rely heavily and almost exclusively on the baseline-derived 95 and 99 percentile thresholds to screen out natural variations. The same-day control threshold may only be useful for dealing with atypical conditions whereby the control station already shows very high Turbidity / SS (e.g. due to illegal dumping or landslip events upstream of the Project).

Given the heavy reliance of the Action and Limit Levels on the baseline-derived 95 percentile and 99 percentile values, the baseline data should be able to represent the natural variations in water quality that are highly seasonal and weather dependent. However, the data collected during that baseline period appeared to be inadequate to cover such natural variations at Tung Chung River. This is evident from the baseline data, which showed that a single rainstorm event (on 1 Sep 2021) can generate huge disparities between control and impact station results. The 4-week baseline period was only able to capture one such rainstorm event, which reduces the reliability of the baseline-derived 95 and 99 percentile thresholds to adequately factor in such weather-related natural variations. Therefore, it would be prudent to incorporate additional baseline data to make the baseline-derived 95 and 99 percentiles more robust.

Existing baseline data at Tung Chung River is available from EPD's routine river water quality monitoring programme, which includes two monitoring stations at Tung Chung River (TC1 at Tung Chung Stream West and TC2 at Tung Chung Stream East). The dataset from EPD is considered to be highly robust as it has been conducted monthly (for most years) since 2000, and directly relevant to this Project as the monitoring locations for TC1 and TC2 are within the Project area. Recognising that the construction programme for this Project will span approx. 10 years, a baseline dataset covering an equivalent timespan would be best suited to providing the appropriate level of robustness needed to represent the baseline for the next 10 years. Hence it is proposed to incorporate EPD's latest 10-year routine river water quality monitoring data along with the baseline data obtained by this Project to generate the baseline-derived 95 percentile and 99 percentile Action and Limit Levels for Tung Chung Stream (West) and Tung Chung Stream (East) respectively.

TCW-WQM1

Due to the tidal nature of TCW-WQM1, the control stations TCW-WQM4 and TCW-WQM5A cannot adequately represent the 'upstream' conditions for benchmarking against same day results. There is also no EPD routine marine water quality monitoring station that can represent the area of Tung Chung Bay for supplementing the baseline data at TCW-WQM1. Given these circumstances, the Action and Limit Levels at TCW-WQM1 can only be based on its baseline dataset. In the absence of EPD routine marine water quality monitoring station data at Tung Chung Bay, a supplementary 4-week baseline monitoring was carried out at TCW-WQM1 in October to November 2021 to extend the baseline monitoring dataset for deriving the Action and Limit Levels at TCW-WQM1. The Action and Limit Levels at TCW-WQM1 are thus based on a total of 8-weeks baseline dataset.

Recognising that the construction programme for this Project will span approx. 10 years, the baseline conditions will be reviewed regularly and updated as appropriate, to demonstrate the continued suitability of the impact and control monitoring.

4.8        Action and Limit Levels

The criteria for Action and Limit Levels for DO, Turbidity and SS, taking into account the update proposed in Section 4.7.4, are summarized in Table 4.5.

Table 4.5: Updated Criteria for Action and Limit Levels for Impact Water Quality Monitoring

Parameters

Action Level

Limit Level

Tung Chung Stream (West)

DO in mg/L

5 percentile of baseline data

1 percentile of baseline data

SS in mg/L

95 percentile of baseline data + EPD latest 10-year data for Tung Chung River (TC1)

or 120% of upstream control station at the same tide of the same day, whichever is higher

99 percentile of baseline data + EPD latest 10-year data for Tung Chung River (TC1)

or 130% of upstream control station at the same tide of the same day, whichever is higher

Turbidity in NTU

95 percentile of baseline data + EPD latest 10-year data for Tung Chung River (TC1)

or 120% of upstream control station at the same tide of the same day, whichever is higher

99 percentile of baseline data + EPD latest 10-year data for Tung Chung River (TC1)

or 130% of upstream control station at the same tide of the same day, whichever is higher

Tung Chung Stream (East)

DO in mg/L

5 percentile of baseline data

1 percentile of baseline data

SS in mg/L

95 percentile of baseline data + EPD latest 10-year data for Tung Chung River (TC2)

or 120% of upstream control station at the same tide of the same day, whichever is higher

99 percentile of baseline data + EPD latest 10-year data for Tung Chung River (TC2)

or 130% of upstream control station at the same tide of the same day, whichever is higher

Turbidity in NTU

95 percentile of baseline data + EPD latest 10-year data for Tung Chung River (TC2)

or 120% of upstream control station at the same tide of the same day, whichever is higher

99 percentile of baseline data + EPD latest 10-year data for Tung Chung River (TC2)

or 130% of upstream control station at the same tide of the same day, whichever is higher

TCW-WQM1

 

 

DO in mg/L

5 percentile of baseline data

1 percentile of baseline data

SS in mg/L

95 percentile of baseline data

99 percentile of baseline data

Turbidity in NTU

95 percentile of baseline data

99 percentile of baseline data

Notes:

(1)          For DO, non-compliance occurs when monitoring results is lower than the limits.

(2)          For SS and Turbidity, non-compliance occurs when monitoring results is larger than the limits.

(3)          Water depth-separated measurements (such as DO surface and middle and DO bottom) is not applicable due to very shallow depth of the monitoring locations in Tung Chung West whereby only one sampling depth applies.

(4)          EPD's latest 10-year data for Tung Chung River (2011 - 2020) obtained from EPD's website https://www.epd.gov.hk/epd/epic/english/data_river_monitoring.html.

The calculated Action and Limit levels for Tung Chung Stream (West), Tung Chung Stream (East) and TCW-WQM1 are shown in Table 4.6. Note that as recommended in Section 4.7.4, the DO results from TCW-WQM4 are excluded in the determination of the Action and Limit Levels for DO at Tung Chung Stream (West).

Table 4.6: Calculated Action and Limit Levels for Impact Water Quality Monitoring

Parameters

Action Level

Limit Level

Tung Chung Stream (West)

DO in mg/L

3.4 mg/L

3.3 mg/L

SS in mg/L

7.0 mg/L or

120% of upstream control station at the same tide of the same day, whichever is higher

16.9 mg/L or

130% of upstream control station at the same tide of the same day, whichever is higher

Turbidity in NTU

6.7 NTU or

120% of upstream control station at the same tide of the same day, whichever is higher

22.0 NTU or

130% of upstream control station at the same tide of the same day, whichever is higher

Tung Chung Stream (East)

DO in mg/L

4.2 mg/L

4.0 mg/L

SS in mg/L

7.2 mg/L or

120% of upstream control station at the same tide of the same day, whichever is higher

9.7 mg/L or

130% of upstream control station at the same tide of the same day, whichever is higher

Turbidity in NTU

9.8 NTU or

120% of upstream control station at the same tide of the same day, whichever is higher

22.5 NTU or

130% of upstream control station at the same tide of the same day, whichever is higher

TCW-WQM1

 

 

DO in mg/L

2.2 mg/L

1.8 mg/L

SS in mg/L

7.3 mg/L

9.7 mg/L

Turbidity in NTU

24.7 NTU

35.3 NTU

Notes:

(1)          For DO, non-compliance occurs when monitoring results is lower than the limits.

(2)          For SS and Turbidity, non-compliance occurs when monitoring results is larger than the limits.

(3)          Action and Limit Levels do not apply to TCW-WQM4 and TCW-WQM5A which are upstream control stations.

 

4.9        Event and Action Plan

Should non-compliance of the water quality criteria occur, actions in accordance with the Event and Action Plan in the Table 4.7 below shall be carried out.


Table 4.7: Event and Action Plan for Construction Water Quality

Event

Action

ET

IEC

ER

Contractor

Action Level Exceedance for one sampling day

1. Inform IEC, Contractor and ER;

2. Check monitoring data, all plant, equipment and Contractor's working methods; and

3. Discuss remedial measures with IEC and Contractor and ER.

1. Discuss with ET, ER and Contractor on the implemented mitigation measures;

2. Review proposals on remedial measures submitted by Contractor and advise the ER accordingly; and

3. Review and advise the ET and ER on the effectiveness of the implemented mitigation measures.

1. Discuss with IEC, ET and Contractor on the implemented mitigation measures;

2. Make agreement on the remedial measures to be implemented;

3. Supervise the implementation of agreed remedial measures.

1. Identify source(s) of impact;

2. Inform the ER and confirm notification of the non-compliance in writing;

3. Rectify unacceptable practice;

4. Check all plant and equipment;

5. Consider changes of working methods;

6. Discuss with ER, ET and IEC and purpose remedial measures to IEC and ER; and

7. Implement the agreed mitigation measures.

Action Level Exceedance for more than one consecutive sampling days

1. Repeat in-situ measurement on next day of exceedance to confirm findings;

2. Inform IEC, contractor and ER;

3. Check monitoring data, all plant, equipment and Contractor's working methods;

4. Discuss remedial measures with IEC, contractor and ER

5. Ensure remedial measures are implemented.

1. Discuss with ET, Contractor and ER on the implemented mitigation measures;

2. Review the proposed remedial measures submitted by Contractor and advise the ER accordingly; and

3. Review and advise the ET and ER on the effectiveness of the implemented mitigation measures.

1. Discuss with ET, IEC and Contractor on the proposed mitigation measures;

2. Make agreement on the remedial measures to be implemented ; and

3. Discuss with ET, IEC and Contractor on the effectiveness of the implemented remedial measures.

1. Identify source(s) of impact;

2. Inform the ER and confirm notification of the non-compliance in writing;

3. Rectify unacceptable practice;

4. Check all plant and equipment and consider changes of working methods;

5. Discuss with ET, IEC and ER and submit proposal of remedial measures to ER and IEC within 3 working days of notification; and

6. Implement the agreed mitigation measures.

Limit Level Exceedance for one sampling day

1. Repeat in-situ measurement on next day of exceedance to confirm findings;

2. Inform IEC, contractor and ER;

3. Rectify unacceptable practice;

4. Check monitoring data, all plant, equipment and Contractor's working methods;

5. Consider changes of working methods;

6. Discuss mitigation measures with IEC, ER and Contractor; and

7. Ensure the agreed remedial measures are implemented.

1. Discuss with ET, Contractor and ER on the implemented mitigation measures;

2. Review the proposed remedial measures submitted by Contractor and advise the ER accordingly; and

3. Review and advise the ET and ER on the effectiveness of the implemented mitigation measures.

1. Discuss with ET, IEC and Contractor on the implemented remedial measures;

2. Request Contractor to critically review the working methods;

3. Make agreement on the remedial measures to be implemented; and

4. Discuss with ET, IEC and Contractor on the effectiveness of the implemented remedial measures.

1. Identify source(s) of impact;

2. Inform the ER and confirm notification of the non-compliance in writing;

3. Rectify unacceptable practice;

4. Check all plant and equipment and consider changes of working methods;

5. Discuss with ET, IEC and ER and submit proposal of additional mitigation measures to ER and IEC within 3 working days of notification; and

6. Implement the agreed remedial measures.

Limit Level Exceedance for more than one consecutive sampling days

1. Inform IEC, Contractor and ER;

2. Check monitoring data, all plant, equipment and Contractor's working methods;

3. Discuss mitigation measures with IEC, ER and Contractor; and

4. Ensure mitigation measures are implemented; and

5. Increase the monitoring frequency to daily until no exceedance of Limit Level for two consecutive days.

1. Discuss with ET, Contractor and ER on the implemented mitigation measures;

2. Review the proposed remedial measures submitted by Contractor and advise the ER accordingly; and

3. Review and advise the ET and ER on the effectiveness of the implemented mitigation measures.

1. Discuss with ET, IEC and Contractor on the implemented remedial measures;

2. Request Contractor to critically review the working methods;

3. Make agreement on the remedial measures to be implemented;

4. Discuss with ET and IEC on the effectiveness of the implemented mitigation measures; and

5. Consider and instruct, if necessary, the Contractor to slow down or to stop all or part of the relevant site construction activities until no exceedance of Limit level.

1. Identify source(s) of impact;

2. Inform the ER and confirm notification of the non-compliance in writing;

3. Rectify unacceptable practice;

4. Check all plant and equipment and consider changes of working methods;

5. Discuss with ET, IEC and ER and submit proposal of additional mitigation measures to ER and IEC within 3 working days of notification; and

6. Implement the agreed remedial measures.

7. As directed by the ER, to slow down or stop all or part of the relevant site construction activities until no exceedance of Limit level.

 


5        Ecology

5.1        Background

As described in Section 9.5.1.5 of the Environmental Impact Assessment (EIA) Report for TCNTE (AEIAR-196/2016), in order to restore the ecological connection between the upstream and downstream of Tung Chung Stream, it is proposed to revitalise most part of its existing channelised section, and convert together with its natural section into amenity uses and for environmental enhancement, i.e. in a form as a River Park. This River Park would occupy an area of approximately 3.3ha along a total length of 775m and would aim to promote eco-education by setting up viewing decks / boardwalk, passive recreation zone for appreciation of natural environment.  Besides, this Park would also help to prevent massive infrastructures within the Park to avoid impacts due to construction and human disturbance.

According to Section 11.4.5 of the Updated EM&A Manual (Revision 1) dated 15 May 2018 for EP No. EP-519/2016 TCNTE, a 12-month pre-construction baseline ecological monitoring of the Tung Chung River Park and other Public Works (including road crossing, and attenuation and treatment pond) is required to be undertaken.

To match with the construction program of TCW which was planned to be commenced in Q3/Q4 2021, CEDD has appointed the Environmental Team of Tung Chung New Town Extension (East) ("TCE ET") to prepare a Detailed Ecological and Water Quality Monitoring Plan ("Monitoring Plan") in early 2020. The Monitoring Plan was eventually agreed with EPD and AFCD in mid 2020, and the pre-construction baseline ecological monitoring was commenced in August 2020 accordingly by the TCE ET.

The 12-month pre-construction baseline ecological monitoring was completed in July 2021. The TCE ET has summarized all the baseline monitoring results in an Ecological and Water Quality Final Monitoring Report ("Monitoring Report") which was ready in August 2021 and passed to the TCW ET for the preparation of TCW Baseline Monitoring Report.

As stated in Section 11.4.5 of the Updated EM&A Manual, Action and Limit Levels with reference to the baseline survey data, by considering the species (taxa diversity or abundance) and season, should be established for evaluating the ecological impact during the construction phase. When these limits are triggered, appropriate responses shall be made. The following section will present the analysis of data extracted from the Monitoring Report for the consideration of establishing the Action and Limit Levels and an Event and Action Plan.

5.2        Setup of the Pre-construction Baseline Monitoring

5.2.1         Monitoring Locations

As presented in Section 2.1 of the Monitoring Plan, the ecological and water quality baseline monitoring was conducted at a total of seven (7) monitoring locations at Tung Chung Stream covering both River Park and other Public Works.

Study Area in association with River Park works - this part of monitoring includes four monitoring locations (RP1, RP2, RP3 and RP4), which cover the Conservation Zone (existing natural section), Revitalization Zone (existing channelised section to be completely revitalised at Construction stage), and both the upstream and downstream sections of Tung Chung Stream within 30 meters outside the boundary of River Park.

Study Area in association with other Public Works - this part of monitoring includes three monitoring locations (PW1, PW2 and PW3), which are in the vicinity of other Public Works area.

Locations of these monitoring stations are presented in Table 5.1 and Appendix D1. Representative photos of these monitoring stations are shown in Appendix D2. Note that the exact monitoring locations were subject to fine adjustment based on site conditions (e.g. adverse weather conditions, blockage by plants, rocks or other obstacles).

Table 5.1: Baseline Ecological and Water Quality Monitoring Stations 

Monitoring Station

Description

Coordinates

 

Easting

Northing

Latitude (N)

Longitude (E)

RP1

Conservation Zone (Natural Section)

811150

814469

22°16'07.95"N

113°55'59.41"E

RP2

Upstream of River Park

811083

814895

22°16'21.77"N

113°55'57.05"E

RP3

Revitalisation Zone (Channelised Section)

811036

815076

22°16'27.66"N

113°55'55.38"E

RP4

Downstream of River Park

810846

815402

22°16'38.25"N

113°55'48.72"E

PW1

Near Public Works

811099

814589

22°16'11.83"N

113°55'57.63"E

PW2

Near Public Works

810933

815318

22°16'35.54"N

113°55'51.79"E

PW3

Near Public Works

810789

815658

22°16'46.56"N

113°55'46.71"E

5.2.2         Monitoring Period and Frequency  

According to Section 11.4.5 of the Updated EM&A Manual, pre-construction baseline monitoring shall be carried out on a monthly basis for a 12-month duration for River while that for other Public Works (road crossings, polders, and stormwater attenuation and treatment ponds) shall be at least 6 months and covering the wet season.

As presented in Section 2.2 of the Monitoring Plan, the ecological and water quality baseline monitoring was conducted at the Study Areas in association with River Park works (RP1, RP2, RP3 and RP4), and other Public Works (PW1, PW2 and PW3) for a duration of 12 months and 6 months respectively. The monitoring schedule is shown in Table 5.2 below.

Study Area in association with River Park works - this part of monitoring was conducted once every month for a 12-month duration from August 2020 to July 2021. 

Study Area in association with other Public Works - this part of monitoring was conducted once every month for a 6-month duration from August 2020 to January 2021.

Table 5.2: Baseline Ecological and Water Quality Monitoring Schedule 

Month

River Park Study Area

(RP1, RP2, RP3 and RP4)

Other Public Works Study Area

(PW1, PW2 and PW3)

 

Ecological Monitoring

Water Quality Monitoring

Ecological

Monitoring

Water Quality Monitoring

Aug 2020

21 & 24 Aug 2020

21 Aug 2020

21 & 24 Aug 2020

21 Aug 2020

Sep 2020

15 & 25 Sep 2020

15 Sep 2020

15 & 25 Sep 2020

15 Sep 2020

Oct 2020

20 & 22 Oct 2020

20 Oct 2020

20 & 22 Oct 2020

20 Oct 2020

Nov 2020

18 & 19 Nov 2020

18 Nov 2020

18 & 19 Nov 2020

18 Nov 2020

Dec 2020

16 & 17 Dec 2020

17 Dec 2020

16 & 17 Dec 2020

17 Dec 2020

Jan 2021

15 & 18 Jan 2021

15 Jan 2021

15 & 18 Jan 2021

15 Jan 2021

Feb 2021

18 Feb 2021

18 Feb 2021

-

-

Mar 2021

26 Mar 2021

26 Mar 2021

-

-

Apr 2021

22 Apr 2021

22 Apr 2021

-

-

May 2021

17 May 2021

17 May 2021

-

-

Jun 2021

25 Jun 2021

25 Jun 2021

-

-

Jul 2021

14 Jul 2021

14 Jul 2021

-

-

5.2.3         Monitoring Requirement

According to Section 11.4.5 of the Updated EM&A Manual, the monitoring items should cover the environment of the stream courses, the water quality, and the stream fauna ("aquatic fauna", as adopted by the Monitoring Report). Ecological monitoring of stream fauna should include fish and aquatic invertebrate, while the methodology should follow standard methods of direct observation and active search. The frequency should be monthly.

5.2.4         Monitoring Methodology

5.2.4.1            Aquatic Fauna

As presented in Section 3.1 of the Monitoring Plan, monitoring of aquatic fauna (includes fish and aquatic invertebrates) at the River Park and other Public Works Study Areas were conducted in accordance with the methodology following relevant annex of EIAO-TM (Annex 16) and the EIAO Guidance Notes (GN 6/2010, GN 7/2010, GN 10/2010 and GN 11/2010). Several survey methods which covered different components of the stream fauna were used to monitor the study areas to yield a comprehensive result.  

Direct observation and active search were conducted within the survey zones/sections. Direct observation covered all along the accessible part of the watercourse to provide a species list of fish and invertebrates with corresponding relative abundance. 

Direct observation is a simple and least intrusive method to survey fish which is suitable to conduct in shallow, slow-moving streams with clear water and with minimal vegetation; while active search is used to collect fishes and aquatic invertebrates in deeper water, in turbid locations, in stream with dense aquatic vegetation and within stream substrate.

At each sampling location, two replicates of baited fish cages were deployed for a duration of at least one hour.  All collected fish and other aquatic invertebrate species were recorded and their abundance were counted.  This method may collect fishes which are wary of humans.  Permit from the AFCD was obtained before the use of any equipment to collect aquatic fauna in any streams and watercourses.

Besides baited fish cages, at least two replicates of kick sampling were performed at each monitoring station to obtain invertebrate (and fish) samples.  Kick sampling is a relatively quick method to survey benthic invertebrates in shallow fast-flowing streams.  A ~30 cm x ~30 cm kick sampler with ~0.5 mm mesh size was placed on the stream bed and the area just upstream of the sampler were vigorously disturbed by kicking for one minute.  The contents of the net were transferred to suitable containers with freshwater for identification and counting in situ.  All identifiable samples were released back to the sampling locations. If there were unidentifiable samples, representative samples would be preserved with ethanol and transferred to laboratory for further identification.

5.2.4.2           Water Quality

The monitoring methodology including water quality parameters, monitoring procedures, instrument required and methods for in situ measurement and laboratory analyses were set as presented in Section 3.2 of the Monitoring Plan.

Water quality monitoring, including in situ measurements and collection of water samples for laboratory analysis, was conducted at each monitoring location. Duplicate water samples were collected at surface water level at each sampling location.

Water quality parameters including Dissolved Oxygen (in % saturation and mg/L), pH value, temperature, turbidity and salinity were measured in situ while the other parameters, including Suspended Solids (SS), Ammonia, Total Kjeldahl Nitrogen (TKN), Total Phosphorus (TP), Escherichia coli (E. coli), 5-day Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD) and Oil & Grease, were measured at a HOKLAS accredited laboratory for water quality analysis. Other relevant data, including time, water depth, weather conditions and special phenomena or works underway in the vicinity were recorded.

The measured water quality parameters and laboratory testing method are shown in Table 5.3.

Table 5.3: Water Quality Monitoring Parameters and Testing Methods

Parameter

 

 

In situ measurements

Instrument Range Capability (1)

Measurement Resolution

pH

0 - 14 pH units

0.01 pH units

Salinity

0 - 70 ppt

0.01 ppt

Temperature

-5 - 70°C

0.1°C

Turbidity

0 - 4000 NTU

0.1 NTU

Dissolved Oxygen (DO)

0 - 50 mg/L

0.1 mg/L

 

0 - 500% saturation

0.1% saturation

Laboratory testing and analyses

Method Reference

Level of Reporting

Suspended Solids (SS)

APHA 2540 D

0.5 mg/L

Ammonia as N

APHA 4500 NH3 G

0.01 mg/L

Total Kjeldahl Nitrogen (TKN) as N

APHA 4500 P: J;
APHA 4500 NO3: I

0.05 mg/L

Total Phosphorus as P

APHA 4500 P: J

0.01 mg/L

E. coli

TM09/EC/10/98 Issue 3, HKEPD

1 CFU/100mL

5-day Biochemical Oxygen Demand (BOD5)

APHA 5210 B

1 mg/L

Chemical Oxygen Demand (COD)

APHA 5220 B

2 mg/L

Oil & Grease

APHA 5520 B

2 mg/L

Note (1):  Specifications based on YSI ProDSS Multiparameter Water Quality Meter  

5.2.5         Monitoring Result

5.2.5.1           Site Conditions

As extracted from the Monitoring Report, the physical environment of the monitoring stations for the River Park Study Area (RP1 to RP4) and other Public Works Study Area (PW1 to PW3) are summarized and presented in Table 5.4.

Table 5.4: Physical Environment of the Monitoring Stations

Station Name

Location

Physical Environment

RP1

Conservation Zone (Natural Section)

Fast flowing natural stream.  The substrate was dominant with boulders and rocks, and sands were sometimes observed.  Water was generally clear and the river depth varied which was usually within 60cm.  Woodland with dense vegetation was on the river banks.

RP2

Upstream of River Park

Moderate fast flowing natural stream.  The substrate was in the form of boulders, rocks, sand and silt mixture.  Water was generally clear and the river depth varied which was usually within 50cm.  Short but dense herbaceous vegetation was on the right bank of the stream, while dense woodland was on the left bank. Household wastes, such as food packages, were observed near the left bank of the stream.

RP3

Revitalisation Zone (Channelised Section)

Slow flowing artificial, concretised and channelised stream.  Pavement was the dominant substrate with little sand and rock.  Algal mat was observed at this site.  Water was generally clear and the river depth was usually within 10cm.  Short but dense herbaceous vegetation was on the river banks.  A culvert was on the right bank of the stream, and a footbridge was on the upstream of the location.

RP4

Downstream of River Park

The channelised section of Tung Chung Stream ended at the upstream of RP4. RP4 is a moderate fast flowing natural stream close to the estuary, so the physical and biochemical parameters are affected by the estuary and tidal activities.  The substrate was in the form of boulders, rocks, sand and silt mixture.  Water was sometimes clear and the river depth varied which was usually within 80cm.  Woody plants and herbaceous plants were along the river banks.  Dead vegetation was observed in the stream in the first few months of survey, which was then cleared.  The dead vegetation was observed to be shelter of some fishes and aquatic invertebrates.  Household wastes, such as food packages and abandoned furniture, were frequently observed in the stream or on the river bank.

PW1

Near Public Works

Fast flowing natural stream.  The substrate was dominant with boulders and rocks, and sand was sometimes observed.  Water was generally clear and the river depth varied which was usually within 40cm.  Woodland with dense vegetation was on the river banks.  

PW2

Near Public Works

Slow flowing artificial, concretised and channelised stream.  Pavement was the dominant substrate with little sand and rock.  Algal mat was observed at this site.  Water was generally clear and the river depth varied which was usually within 15cm.  Short but dense herbaceous vegetation was on the left bank of the stream, woody plants and herbaceous plants were on right bank of the river.  

PW3

Near Public Works

A natural estuary. Water was brown, slow flowing and usually turbid.  Water depth varied which was usually within 110cm.  The substrate was dominant with sand and mud.  Dense mangroves were on the shores of the estuary. 

5.2.5.2           Taxa Diversity of Aquatic Fauna

Three (3) types of survey were conducted, which are (i) Direct Observation, (ii) Kick Sampling, and (iii) Baited Fish Cage. Taxa diversity, i.e. number of species, of each monitoring station was obtained based on the cumulative count of species recorded in the three survey methods over the entire 12-month survey period. The cumulative result on taxa diversity of aquatic invertebrate and fish have been summarised in Table 5.5 and Table 5.6 respectively. Full details of the cumulative data extracted from the Monitoring Report are listed in Appendix D3 and Appendix D4.

Aquatic Invertebrate - For both River Park and other Public Works Study Areas, a total of 20 aquatic invertebrate species was recorded, respectively with station RP4 supporting the highest number of species, i.e. 14. The species recorded comprises of macroinvertebrates(1) such as shrimp, crab, snail, dragonfly larvae and water strider. Besides, two (2) species of mosquito larvae, Chironomidae sp. and Tipulidae sp., and one (1) species of water mite was recorded.  

Fish - For both River Park and other Public Works Study Areas, a total of 28 fish species was recorded, with stations RP4 and PW3 support the highest number of species, i.e., 18 and 12 respectively. The relatively high taxa diversity in these stations is largely due to its proximity to river mouth in which the fish community comprises of the estuarine fish.

Note (1):  For effective evaluation of the monitoring result, only macroinvertebrates will be accounted in the consideration of Action and Limit Levels.

Table 5.5: Cumulative Record of Aquatic Invertebrate Species

Common Name

Species Name

River Park Study Area

Public Works Study Area

 

 

RP1

RP2

RP3

RP4

PW1

PW2

PW3

Freshwater Shrimp

Caridina cantonensis

Freshwater Prawn

Macrobrachium sp.

-

Amphipoda

Crab

Varuna litterata

Mitten Crab

Eriocheir japonica

-

Parasesarma bidens

-

Portunus sp.

Freshwater Snail

Clithon retropictus

-

Radix plicatulus

-

Tarebia granifera

Common Blue Jewel

Heliocypha perforata

Chinese Greenwing (Larva)

Neurobasis chinensis

Emerald Cascader (Larva)

Zygonyx iris (1)

-

Ephemeroptera sp.

Unidentified Skimmer (Larva)

Orthetrum sp.

Water Strider

Ptilomera tigrina

-

Rhagovelia sp.

Blood Worm (2)

Chironomidae sp.

Cranefly Larva

Tipulidae sp. (2)

Water Mites

Hydrachnidae sp. (2)

Cumulative Number of

Aquatic Invertebrate Species

9

8

8

14

5

9

5

Cumulative Number of

Macroinvertebrate Species

8

7

7

12

4

7

5

Note (1):  Species of conservation importance (Fellowes, 2002)

Note (2):  Blood Worm Chironomidae sp, Cranefly Larva Tipulidae sp., and Water Mites Hydrachnidae sp. are not counted as macroinvertebrates.

Table 5.6: Cumulative Record of Fish Species

Common Name

Species Name

River Park Study Area

Public Works Study Area

 

 

RP1

RP2

RP3

RP4

PW1

PW2

PW3

Yellowfin Seabream

Acanthopagrus latus

Beijiang Thick-lipped Barb

Acrossocheilus beijiangensis (1)

Asiatic Glassfish

Ambassis sp.

Chinese Barb

Barbodes semifasciolatus

Redbelly Tilapia

Coptodon zillii

Black Sleeper

Eleotris melanosoma

Indo-Pacific Tropical Sand Goby

Favonigobius reichei

Mosquito Fish

Gambusia affinis

Long Rayed Silverbiddy

Gerres filamentosus

Common Silverbiddy

Gerres oyena

Fork Tongue Goby

Glossogobius giuris

Jewelfish

Hemichromis stellifer

Broken-band Hillstream Loach

Liniparhomaloptera disparis

Grey Mullet

Mugil cephalus

Mullet

Family: Mugilidae

Rice Fish

Oryzias curvinotus (1)

Predaceous Chub

Parazacco spilurus (2)

Common Mudskipper

Periophthalmus modestus

Sucker-belly Loach

Pseudogastromyzon myersi

Javanese Fatnose Goby

Pseudogobius javanicus

-

Rhinogobius duospilus

Barcheek Goby

Rhinogobius giurinus

Spotted Scat

Scatophagus argus

Striped Loach

Schistura fasciolata

Jarbua Terapon

Terapon jarbua

Chameleon Goby

Tridentiger trigonocephalus

Swordtail

Xiphophorus hellerii

Variable Platyfish

Xiphophorus variatus

Cumulative Number of

Fish Species

9

10

4

18

9

2

12

Note (1):  Species of conservation importance (Fellowes, 2002)

Note (2):  Species of conservation importance (Zheng & Wang,1998)

5.2.5.3           Abundance of Aquatic Fauna

As the abundance of aquatic fauna presented in the Monitoring Report were recorded by a mix of quantitative sampling methods (baiting and kick sampling) and qualitative estimate (direct observation), the abundance can only be indicatively presented.

As stipulated in the Monitoring Report, the occurrence frequency for the aquatic invertebrate and fish species, which refers to the number of surveys in which each species was encountered over the survey period (i.e. 12 months for River Park Study Area and 6 months for other Public Works Study Area), is summarised in Table 5.7 and Table 5.8 respectively. This could reveal the commonness of the species in the Study Areas. The details on the abundance of aquatic fauna extracted from the Monitoring Report are presented in Appendix D5 and Appendix D6.

Aquatic Invertebrate - among the macroinvertebrate species recorded, Freshwater Shrimp Cardina cantonensis, Macrobrachium sp., Orthetrum sp., Water Strider Ptilomera tigrine, and Emerald Cascader (Larva) Zygonxy iris are relatively common across various monitoring stations.

Fish - Among the fish species recorded, Predaceous Chub Parazacco spilurus and Variable Platyfish Xiphophorus variatus are commonly recorded in most of the survey, except station PW3, which is mostly influenced by estuarine environment. A species of conservation concern, Beijiang Thick-lipped Barb Acrossocheilus beijiangensis, was commonly recorded across stations RP1, RP2, RP4 and PW1. It is worth noting that another species of conservation concern Rice Fish Oryzias curvinotus is restricted in RP4 but quite regularly observed. 

Table 5.7: Occurrence Frequency of Aquatic Invertebrate Species Recorded

Common Name

Species Name

River Park Study Area

Public Works Study Area

 

 

RP1

RP2

RP3

RP4

PW1

PW2

PW3

Freshwater Shrimp

Caridina cantonensis

11

8

 

3

3

 

 

Freshwater Prawn

Macrobrachium sp.

6

4

 

5

2

2

 

-

Amphipoda

 

 

 

 

 

 

1

Crab

Varuna litterata

 

 

1

3

 

 

2

Mitten Crab

Eriocheir japonica

2

 

2

1

2

 

 

-

Parasesarma bidens

 

 

 

 

 

 

2

-

Portunus sp.

 

 

 

 

 

 

2

Freshwater Snail

Clithon retropictus

 

 

6

4

 

4

 

-

Radix plicatulus

 

 

1

1