CONTENTS:

1.                  INTRODUCTION............................................................................................................. 2

2.                  MONITORING LOCATIONS............................................................................................. 3

3.                  PROCEDURES................................................................................................................. 6

4.                  MONITORING FREQUENCY AND ARRANGEMENTS........................................................ 7

5.                  LABORATORY MEASUREMENT / ANALYSIS.................................................................. 8

6.                  MONITORING RESULTS AND OBSERVATIONS............................................................... 9

 

TABLES:

 

Table 1.1         Silt curtain types and their respective target of works / site activities Table 2.1 Monitoring Stations for the Silt Curtain Efficiency Test

Table 2.2         Water Quality Monitoring Equipment

Table 2.3            Water Quality Parameters to be tested during Pilot Test

Table 4.1         Detailed Monitoring Framework of Silt Curtain Efficiency Test

Table 5.1         Analytical Methods Applied to Marine Water Quality Samples

Table 6.1         Summary of Water Quality Monitoring Results (Baseline)

Table 6.2         Summary of Water Quality Monitoring Results (Impact) - Average SS (mg/L)

Table 6.3         Summary of Water Quality Monitoring Results (Impact) - Average DO (mg/L)

Table 6.4         Summary of Water Quality Monitoring Results (Impact) - Average Salinity (ppt)

 Table 6.5         Summary of Water Quality Monitoring Results (Impact) - Average Temperature (oC)

Table 6.6         Summary of Water Quality Monitoring Results (Impact) - Average Turbidity (NTU)

Table 6.7            Silt Removal Efficiencies of the Combined Use of Cage and Floating Type Silt Curtains at Outfall Shaft Area

 

FIGURES:

 

Figure 1           Monitoring Stations for the Silt Curtain Efficiency Test

 

 

 

APPENDICES:

 

Appendix A:     Copy of the Calibration Certificates and Certificate of Accreditation of Laboratory

Appendix B:      Water Quality Monitoring Results Appendix C: Laboratory Testing Report Appendix D: Monitoring Photos


 

 

 

 

 

1.                 INTRODUCTION

 

1.1.            According to the EM&A Manual, the pilot test shall be conducted at the proposed seawater intake on the first two days of dredging activities. In view that dredging activities were conducted first at the Outfall Shaft Area, silt curtain monitoring locations were adjusted accordingly. Given the predicted short dredging period with inconsiderable volume of dredging volume that would be anticipated, a small-scale efficiency test was adopted.

 

1.2.            Pilot test was carried out on the first two days of dredging to ensure sufficient silt removal efficiency can be provided by the proposed silt curtain system with achievable loss reduction factor against EIA assumption at ≥ 95%. The pilot test included parameters that could be affected by dredging activities such as turbidity and suspended solids as well other general water quality parameters (i.e. dissolved oxygen, salinity and temperature) covering both flood and ebb tide. Other relevant data were also recorded during the test, including sampling locations, water depth, time, weather conditions, sea conditions, tidal stage, current direction and velocity, special phenomena and work activities undertaken around the monitoring and works area that may influence the monitoring results.

 

1.3.            The pilot test was conducted on 16/04/2021 from 08:00 to 18:00 at 5 stations following a baseline event conducted on 10/04/2021 to evaluate the silt removal efficiency of the combined use of single layer floating and cage type silt curtains. Table 1.1 summarizes the silt curtain types and the respective target of works / site activities:

 

Table 1.1        Silt curtain types and their respective target of works / site activities

No. of

type

Silt Curtain Type

Target of works/ site activities

1

Cage type - non-flexible, fixed metal frame silt

curtain attaching to a working barge, not freely drifted by wave actions

 

 

Dredging works at Outfall Shaft Area

 

2

Floating type - flexible, movable silt curtain with single layer of continuous geotextile sheeting tied on 300mm diameter buoys

(floater)

1.4.            This report summarizes the monitoring results of the silt curtain pilot test for the combined use of cage and floating type silt curtains at Outfall Shaft Area.


 

 

 

 

 

2.                 MONITORING LOCATIONS

 

2.1.          Combined Use of Cage and Floating Type Silt Curtains

Impact monitoring of pilot test was conducted at a total of five monitoring stations. The general locations of the sampling stations are described in Table 2.1 and Figure 1.

 

Table 2.1       Monitoring Stations for the Silt Curtain Efficiency Test                                            

Monitoring Stations

Description

Coordinates*

In’

Impact zone - area enclosed by both layers of silt curtains

E: 846697

N: 813765

Oe

Outer zone - downstream location of ebb tide at approximately 100m from the

dredging area

E: 846749 N:813851

 

Of’

Outer zone - downstream location of flood tide at approximately 100m from the

dredging area

E: 846645

N: 813680

Ce

Upstream control station during ebb tide

E: 845800

N: 814110

Cf

Upstream control station during flood tide

E: 848910

N: 813340

* Subject to adjustment according to site activities and situations

 

Figure 1          Monitoring Stations of Silt Curtain Efficiency Test


 

2.2.          Monitoring Parameters & Equipment

 

2.2.1.       Dissolved Oxygen and Temperature Measuring Equipment - The instrument will be a portable, weatherproof dissolved oxygen measuring instrument complete with cable, sensor comprehensive operation manuals, and will be operable from a DC power source. It will be capable of measuring: dissolved oxygen levels in the range of 0 - 20 mg/L and 0 - 200% saturation; and a temperature of 0 - 45 degrees Celsius. It shall have a membrane electrode with automatic temperature compensation complete with a cable of not less than 35 m in length. Sufficient stocks of spare electrodes and cables shall be available for replacement where necessary (e.g. YSI model 59 DO meter, YSI 5739 probe, YSI 5795A submersible stirrer with reel and cable or an approved similar instrument).

 

2.2.2.       Turbidity Measurement Equipment - The instrument will be a portable, weatherproof turbidity-measuring unit complete with cable, sensor and comprehensive operation manuals. The equipment will be operated from a DC power source, it will have a photoelectric sensor capable of measuring turbidity between 0 - 1000 NTU and will be complete with a cable with at least 35 m in length (for example Hach 2100P or an approved similar instrument).

 

2.2.3.       Salinity Measurement Instrument - portable salinometer capable of measuring salinity in the range of 0 - 40 ppt will be provided for measuring salinity of the water at each monitoring location.

 

2.2.4.       Water Depth Gauge - A portable, battery-operated echo sounder (for example Seafarer 700 or a similar approved instrument) will be used for the determination of water depth at each designated monitoring station. This unit will preferably be affixed to the bottom of the work boat if the same vessel is to be used throughout the monitoring period.

 

2.2.5.       Current Velocity and Direction - current meter capable of measuring the velocity and direction of flow in the range of 0 - 6 m/s (+- 0.01 m/s) and to 360° (+- 2°), respectively, will be used (e.g. Falmouth Scientific, Inc. 2- Dimensional Acoustic Current Meter or a similar approved instrument).

 

2.2.6.       Positioning Device - Differential Global Positioning System (DGPS) shall be used during monitoring to allow accurate recording of the position of the monitoring vessel before taking measurements. The DGPS should be suitably calibrated at appropriate checkpoint to verify that the monitoring station is at the correct position before the water quality monitoring commences.

 

2.2.7.       Water Sampling Equipment - A water sampler, consisting of a PVC or glass cylinder of not less than two litres, which can be effectively sealed with cups at both ends, will be used (e.g. Kahlsico Water Sampler 13SWB203 or an approved similar instrument). The water sampler will have a positive latching system to keep it open and prevent premature closure until released by a messenger when the sampler is at the selected water depth.


 

2.2.8.       Sample Container and Storage - Following collection, water samples for laboratory analysis was stored in high density polythene bottles with no preservatives added, packed in ice (cooled to 4°C without being frozen), delivered to the laboratory and analysed.

 

2.2.9.       Calibration of In-Situ Instruments - The turbidimeter was checked and calibrated before use. Turbidimeter was certified by a laboratory accredited under Hong Kong Laboratory Accreditation Scheme (HOKLAS) or other international accreditation scheme, and subsequently re-calibrated at monthly interval throughout all stages of the pilot test. Responses of turbidimeter was checked with certified standard solutions before each use. For the in-situ calibration of field equipment, 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 available so that monitoring can proceed uninterrupted even when some equipment is under maintenance, calibration, etc.

 

2.3.            Summary of the equipment used in the water quality monitoring program of pilot test is presented in Table 2.2.

 

Table 2.2        Water Quality Monitoring Equipment

Equipment

Model

Monitoring   Parameters

/ Use

Quantity

 

Wildco 3L  Water

 

 

Water Sampler

Sampler with

Collection of water sample

1

 

messenger

 

 

Multi-Functional Meter

 

Horiba U-53

Measurement of turbidity, salinity, dissolved oxygen, temperature

 

1

Monitoring Position Equipment

 

Garmin GPSMAP 78s

Determination of water quality monitoring

 

1

 

 

stations

 

Sonar Water Depth Detector

Hummingbird 160 Portable

Determination of water depth

1

Current Meter

Valeport 106

Measurement of current velocity and direction

1

 

2.4.            The water quality parameters to be monitored are tabulated below in Table 2.3.

 

Table 2.3        Water Quality Parameters to be tested during Pilot Test

Water Quality Parameters

Measurement Type*

Suspended Solids (SS)

Laboratory analysis

Turbidity

In-situ

Dissolved Oxygen

In-situ

Salinity

In-situ

Temperature

In-situ

*Other relevant data were also recorded during the test, including sampling locations, water depth, time, weather conditions, sea conditions, tidal stage, current direction and velocity, special phenomena and work activities undertaken around the monitoring and works area that may influence the monitoring results


 

 

 

 

 

3.                 PROCEDURES

3.1.            In advance of the sampling day, ET’s staff checked wind condition on website of Hong Kong Observatory.

 

3.2.            Before getting on the vessel, all persons were equipped with lifejacket, reflective vest, safety helmet and safety shoes properly;

 

3.3.            ET’s staff(s) calibrated the measurement instrument before sampling event;

 

3.4.            At the pier, Coxswain judged local Beaufort Sea Status and weather (e.g. rainstorm, windy, foggy, etc.) whether it is suitable for the sampling work to go on;

 

3.5.            Coxswain parked at the pier and kept steady by keeping the engines on and direction towards the pier for uploading the tools and equipment onto the vessel;

 

3.6.            Trained worker(s) tightened the cool boxes with rope at secure structure of the vessel;

 

3.7.            Vessel was then sailed to the sampling stations with guiding of digital Global Positioning System (GPS). Determination of sampling location was made with referenced to tide information;

 

3.8.            After arriving the sampling station, depth was measured using depth meter in order to determine the sampling depths;

 

3.9.            The water sampler and the multi-functional meter was lowered to the predetermined depths (1m below water surface, mid-depth and 1m above seabed) and the in-situ parameters was recorded at the same time.

 

3.10.        At each measurement, two consecutive measurements of in-situ parameters 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 reading, the reading was discarded and further readings was taken.

 

3.11.        In-situ measurement results included basic measurements such as turbidity, dissolved oxygen, temperature, salinity as well as current speed and direction.

 

3.12.        Water samples for SS (mg/L) measurements were collected at the same depths with water sampler. All the containers filled samples were placed into cool boxes.

 

3.13.        Steps 3.7 to 3.12 were repeated for remaining monitoring locations and the monitoring in next tide;

 

3.14.        Coxswain drove back to pier and parked the vessel at the pier. The cool boxes with container samples were transferred from vessel to pier and handed over to the lab’s representative(s) for conducting the SS testing.


 

 

 

 

 

4.                 MONITORING FREQUENCY AND ARRANGEMENTS

 

4.1.            Monitoring was conducted at all designated stations on the day with commencement of dredging works. The monitoring was conducted at an interval of two hours throughout the sampling day. A total of 7 sampling events were conducted. The first monitoring event (baseline) was conducted right before the dredging event to serve as a baseline condition. Detailed monitoring framework was provided in Table 4.1.

 

Table 4.1        Detailed Monitoring Framework of Silt Curtain Efficiency Test

Time

Monitoring

Stations

Sampling Quantities

Duration

Tide

Day 1

 

14:00

 

Baseline

 

In’, Ce, Oe’,

Cf, Of’

2 replicates x (3 depths

at 5 stations = 30 samples)

Prior to impact monitoring when no dredging work

is carried out

 

N/A

Day 2*

 

08:00

 

Impact

 

In’#, Cf, Of’

2 replicates x (3 depths

at 2 stations +1 depth at

1 station) = 14 samples

First impact sampling event

 

Flood-tide

 

10:00

 

Impact

 

In’#, Cf, Of’

2 replicates x (3 depths

at 2 stations +1 depth at

1 station) = 14 samples

After 2 hours from the previous

sampling event

 

Flood-tide

 

12:00

 

Impact

 

In’#, Ce, Oe

2 replicates x (3 depths

at 2 stations +1 depth at

1 station) = 14 samples

After 2 hours from the previous sampling event

 

Ebb-tide

 

14:00

 

Impact

 

In’#, Ce, Oe

2 replicates x (3 depths

at 2 stations +1 depth at

1 station) = 14 samples

After 2 hours from the previous sampling event

 

Ebb-tide

 

16:00

 

Impact

 

In’#, Ce, Oe

2 replicates x (3 depths

at 2 stations +1 depth at

1 station) = 14 samples

After 2 hours from

the previous sampling event

 

Ebb-tide

 

18:00

 

Impact

 

In’#, Ce, Oe

2 replicates x (3 depths

at 2 stations +1 depth at

1 station) = 14 samples

After 2 hours from the previous

sampling event

 

Ebb-tide

# During dredging operation at the receiving pit, the whole water column inside the enveloped impact station would be readily mixed thus one mid-depth sample would be considered representative. Safety considerations were also taken to minimize the duration of the sampling technician who would stay close to the dredging grab.

 

* Only monitoring stations at the corresponding tide would be required. For instance, only the impact station (In’), control stations for ebb tide (Ce) and outer station for ebb tide (Oe’) would be required for an ebb tide condition.


 

 

 

 

 

5.                 LABORATORY MEASUREMENT / ANALYSIS

 

5.1.            Analysis of suspended solids (SS) was carried out in a HOKLAS accredited laboratory, ACUMEN LABORATORY AND TESTING LIMITED. The certificate of accreditation of the laboratory is attached in Appendix A. 3L water samples were used at the monitoring stations for collecting seawater samples for the laboratory determinations. The determination work started within 24 hours after collection of water samples. The analyses followed the American Public Health Association (APHA) Standard Methods for the Examination of Water and Wastewater or an equivalent method subject to the approval of EPD. The testing method and lowest detection limit are provided in Table 5.1.

 

Table 5.1        Analytical Methods Applied to Marine Water Quality Samples

Determinant

Standard Method

Detection Limit

Suspended Solids (mg/L)

APHA 2540D*

1 mg/L

Note (*): APHA American Public Health Association Standard Methods for the Examination of Water and Wastewater

 

5.2.            The testing laboratory of SS was HOKLAS accredited and comprehensive quality assurance and control procedures were in place in order to ensure quality and consistency in results. The Quality Assurance / Quality Control (QA/QC) was in accordance with the requirements of HOKLAS or international accredited scheme.


 

 

 

 

 

6.                 MONITORING RESULTS AND OBSERVATIONS

 

6.1.            Water quality monitoring was conducted on 10 April 2021 (baseline) and 16 April 2021 (impact) to test the silt removal efficiency for the combined use of cage and floating type silt curtain at Outfall Shaft Area. The monitoring results are summarized in Table 6.1 to Table 6.6. Details of water quality monitoring results are presented in Appendix B.

 

Table 6.1        Summary of Water Quality Monitoring Results (Baseline)

 

Location

Parameters

Suspended Solids

(mg/L)

Turbidity (NTU)

Dissolved Oxygen

(mg/L)

Salinity (ppt)

Temperature (°C)

 

In’

Avg.

3.33

2.50

9.33

30.89

26.50

Min.

2.50

2.10

8.72

30.32

26.30

Max.

4.40

2.80

9.78

31.34

26.70

 

Oe

Avg.

3.73

2.40

9.66

31.21

26.50

Min.

2.90

2.10

9.27

30.74

26.40

Max.

4.60

2.80

10.13

31.46

26.70

 

Of’

Avg.

4.15

2.50

9.31

30.90

26.40

Min.

3.00

2.20

8.92

30.32

26.30

Max.

6.00

2.90

9.65

31.36

26.70

 

Ce

Avg.

3.77

6.50

9.33

31.01

26.60

Min.

2.50

6.30

8.83

30.28

26.40

Max.

6.00

6.60

9.74

31.66

26.70

 

Cf

Avg.

4.37

7.80

9.72

31.04

26.60

Min.

2.70

7.60

9.24

30.51

26.50

Max.

6.50

8.20

10.11

31.61

26.70

Note: "Avg", “Min” and “Max” is the average, minimum and maximum respectively at three water depths.

 

Table 6.2             Summary of Water Quality Monitoring Results (Impact) - Average SS (mg/L)

Measureme nt Time

08:00

10:00

12:00

14:00

16:00

18:00

Tide Information

Mid-flood

Mid-flood

Mid-ebb

Mid-ebb

Mid-ebb

Mid-ebb

Monitoring Stations

In’; Of’; Cf

In’; Of’; Cf

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’;

Ce

In’; Oe’; Ce

In’

30.55

99.40

66.45

60.20

84.70

81.10

Ce

--

--

3.65

4.05

2.92

3.30

Cf

4.23

2.83

--

--

--

--

Of’

3.62

4.15

--

--

--

--

Oe

--

--

3.87

3.23

2.88

3.90


 

Table 6.3            Summary of Water Quality Monitoring Results (Impact) - Average DO (mg/L)

Measureme nt Time

08:00

10:00

12:00

14:00

16:00

18:00

Tide Information

Mid-flood

Mid-flood

Mid-ebb

Mid-ebb

Mid-ebb

Mid-ebb

Monitoring Stations

In’; Of’; Cf

In’; Of’; Cf

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’; Ce

In’

10.95

10.62

10.62

11.11

9.88

10.63

Ce

--

--

10.31

10.90

9.92

10.78

Cf

10.15

10.63

--

--

--

--

Of’

9.28

10.47

--

--

--

--

Oe

--

--

10.66

10.83

10.14

10.84

 

Table 6.4              Summary of Water Quality Monitoring Results (Impact) - Average Salinity (ppt)

Measureme nt Time

08:00

10:00

12:00

14:00

16:00

18:00

Tide Information

Mid-flood

Mid-flood

Mid-ebb

Mid-ebb

Mid-ebb

Mid-ebb

Monitoring Stations

In’; Of’; Cf

In’; Of’; Cf

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’; Ce

In’

28.25

27.18

27.68

27.36

27.65

27.39

Ce

--

--

27.42

27.51

27.72

27.33

Cf

29.06

27.23

--

--

--

--

Of’

28.96

27.28

--

--

--

--

Oe

--

--

27.57

27.69

27.69

27.37

 

Table 6.5              Summary of Water Quality Monitoring Results (Impact) - Average Temperature (oC)

Measureme

nt Time

08:00

10:00

12:00

14:00

16:00

18:00

Tide Information

Mid-flood

Mid-flood

Mid-ebb

Mid-ebb

Mid-ebb

Mid-ebb

Monitoring Stations

In’; Of’; Cf

In’; Of’; Cf

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’; Ce

In’

24.39

24.37

24.39

24.83

24.59

24.38

Ce

--

--

24.41

24.73

24.94

24.34

Cf

24.40

24.45

--

--

--

--

Of’

24.40

24.42

--

--

--

--

Oe

--

--

24.40

24.83

25.02

24.39

 

Table 6.6              Summary of Water Quality Monitoring Results (Impact) - Average Turbidity (NTU)

Measureme nt Time

08:00

10:00

12:00

14:00

16:00

18:00

Tide

Information

Mid-flood

Mid-flood

Mid-ebb

Mid-ebb

Mid-ebb

Mid-ebb

Monitoring Stations

In’; Of’; Cf

In’; Of’; Cf

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’; Ce

In’

37.10

50.40

38.75

52.30

146.50

131.00

Ce

--

--

6.50

6.51

7.83

7.21

Cf

7.92

7.45

--

--

--

--

Of’

2.68

2.48

--

--

--

--

Oe

--

--

2.27

2.96

3.05

3.12

 

6.2.            The weather conditions during the two monitoring dates (i.e. 10 April 2021 and 16 April 2021) were sunny and cloudy respectively. Sea conditions of monitoring days were moderate. Monitoring photos are attached in Appendix D.


 

6.3.            Laboratory testing reports for the analysis of SS in the HOKLAS-accredited laboratory are attached in Appendix C.

 

6.4.            The effectiveness of the proposed silt curtain system can be calculated based on following equation:

 

(SSinside - SSoutside) / SSinside x 100% 95%

 

Note:       The silt removal efficiencies will be calculated by taking the arithmetic means of the three stations throughout different sampling periods.

 

6.5.            The silt removal efficiencies of the silt curtains are tabulated as Table 6.7.

 

Table 6.7        Silt Removal Efficiencies of the Combined Use of Cage and Floating Type Silt Curtains at Outfall Shaft Area

Measurement

Time

08:00

10:00

12:00

14:00

16:00

18:00

Loss Reduction Factor

88.16%

95.82%

94.18%

94.63%

96.60%

95.19%

Tide Information

Mid-flood

Mid-flood

Mid-ebb

Mid-ebb

Mid-ebb

Mid-ebb

Monitoring

Stations

In’; Of’; Cf

In’; Of’; Cf

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’; Ce

In’; Oe’; Ce

6.6.            Comparing the monitoring results to the EIA assumption (≥ 95% loss reduction factor), only the monitoring events at 10:00, 16:00 and 18:00 has met the targeted loss reduction factor.

 

6.7.            Detailed analysis has suggested the Loss Reduction Factor and SS level at the In at 0800 was noticeably lower and resembles as an outlier. Considering the site observations on the sampling event at 0800, the possible causes of the low SS level at the impact monitoring location were concluded:

 

-        Dredging operation has been commenced approximately at 0800, whilst the measurement was conducted sharply at 08:00 to meet the schedule. As relatively small amount of suspending materials was generated at the time of sampling, the insufficient difference between the impact level and background level would have caused underestimation of the efficiency of the silt curtain.

 

-        The water columns in the dredging zone might have not yet been well mixed at 0800.

 

6.8.            Moreover, both downstream (Oe & Of’) and control points (Ce’ & Cf’) recorded comparable or even lower average SS values on the dredging day as compared with the corresponding results of baseline sampling when there is NO dredging work. The silt curtain setup was implied by the monitoring results to be effective to contain any plume dispersion from the central dredging spot.

 

6.9.            In view of the above, the first monitoring data at 0800 would be suggested to be treated as an outlier; and an average Loss Reduction Factors of 95.28% would be obtained from the remaining results.


 

 

 

 

 

Appendix A:          Copy of the Calibration Certificate and Certificate of Accreditation of Laboratory



 

 

 

 

 

 

 

 

 

 

Appendix B:          Water Quality Monitoring Results

 

 

 

 

 

Table B1:                Water Quality Monitoring Results (Baseline)

 

Location

Date

Weather

Sea Condition

Tidal

Water Level

Depth (m)

Time

DO (mg/L)

pH

Sal (ppt)

Temp (oC)

Turbidty (NTU)

Current Velocity (m/s)

Current Direction

CE

20210410

Sunny

Moderate

Mid-Flood

Surface

1.00

15:20

9.74

8.44

31.60

26.71

6.61

0.13

NW

CE

20210410

Sunny

Moderate

Mid-Flood

Surface

1.00

15:20

9.09

8.46

30.28

26.60

6.59

0.14

NW

CE

20210410

Sunny

Moderate

Mid-Flood

Middle

6.60

15:19

9.59

8.48

31.40

26.61

6.45

0.14

NW

CE

20210410

Sunny

Moderate

Mid-Flood

Middle

6.60

15:19

9.12

8.32

31.66

26.65

6.33

0.14

NW

CE

20210410

Sunny

Moderate

Mid-Flood

Bottom

12.20

15:18

9.60

8.46

30.29

26.41

6.37

0.15

NW

CE

20210410

Sunny

Moderate

Mid-Flood

Bottom

12.20

15:18

8.83

8.49

30.84

26.68

6.55

0.14

NW

CF

20210410

Sunny

Moderate

Mid-Flood

Surface

1.00

14:02

9.29

8.54

30.51

26.54

8.20

0.38

NW

CF

20210410

Sunny

Moderate

Mid-Flood

Surface

1.00

14:02

10.04

8.47

31.05

26.70

7.71

0.40

N

CF

20210410

Sunny

Moderate

Mid-Flood

Middle

8.70

14:01

9.92

8.45

31.23

26.55

7.97

0.30

NW

CF

20210410

Sunny

Moderate

Mid-Flood

Middle

8.70

14:01

9.72

8.34

30.79

26.59

7.60

0.45

N

CF

20210410

Sunny

Moderate

Mid-Flood

Bottom

16.40

14:00

10.11

8.46

31.07

26.50

7.75

0.28

NW

CF

20210410

Sunny

Moderate

Mid-Flood

Bottom

16.40

14:00

9.24

8.55

31.61

26.54

7.66

0.35

NW

IN'

20210410

Sunny

Moderate

Mid-Flood

Surface

1.00

14:49

8.72

8.30

30.35

26.60

2.78

0.16

NW

IN'

20210410

Sunny

Moderate

Mid-Flood

Surface

1.00

14:49

9.47

8.29

31.01

26.38

2.75

0.19

NW

IN'

20210410

Sunny

Moderate

Mid-Flood

Middle

6.00

14:48

9.60

8.33

30.99

26.71

2.72

0.18

N

IN'

20210410

Sunny

Moderate

Mid-Flood

Middle

6.00

14:48

9.78

8.44

30.32

26.38

2.26

0.19

NW

IN'

20210410

Sunny

Moderate

Mid-Flood

Bottom

11.00

14:47

9.25

8.38

31.30

26.34

2.53

0.18

NW

IN'

20210410

Sunny

Moderate

Mid-Flood

Bottom

11.00

14:47

9.16

8.51

31.34

26.69

2.13

0.14

NW

OE'

20210410

Sunny

Moderate

Mid-Flood

Surface

1.00

14:27

10.13

8.27

31.23

26.39

2.53

0.20

N

OE'

20210410

Sunny

Moderate

Mid-Flood

Surface

1.00

14:27

9.30

8.25

30.74

26.68

2.06

0.17

NW

OE'

20210410

Sunny

Moderate

Mid-Flood

Middle

4.75

14:26

9.27

8.38

31.23

26.50

2.41

0.18

NW

OE'

20210410

Sunny

Moderate

Mid-Flood

Middle

4.75

14:26

9.80

8.35

31.31

26.35

2.16

0.19

NW

OE'

20210410

Sunny

Moderate

Mid-Flood

Bottom

8.50

14:25

9.78

8.21

31.46

26.44

2.33

0.19

N

OE'

20210410

Sunny

Moderate

Mid-Flood

Bottom

8.50

14:25

9.66

8.36

31.31

26.64

2.84

0.16

NW

OF'

20210410

Sunny

Moderate

Mid-Flood

Surface

1.00

14:38

8.92

8.49

31.36

26.37

2.19

0.19

NW

OF'

20210410

Sunny

Moderate

Mid-Flood

Surface

1.00

14:38

9.34

8.41

30.66

26.31

2.24

0.18

NW

OF'

20210410

Sunny

Moderate

Mid-Flood

Middle

5.10

14:37

9.50

8.40

31.32

26.37

2.59

0.14

NW

OF'

20210410

Sunny

Moderate

Mid-Flood

Middle

5.10

14:37

8.98

8.51

30.46

26.58

2.86

0.20

NW

OF'

20210410

Sunny

Moderate

Mid-Flood

Bottom

9.20

14:36

9.65

8.25

30.32

26.33

2.50

0.13

NW

OF'

20210410

Sunny

Moderate

Mid-Flood

Bottom

9.20

14:36

9.45

8.48

31.25

26.70

2.45

0.17

NW


 

Table B2:                Water Quality Monitoring Results (Impact)

 

Location

Date

Weather

Sea Condition

Tidal

Water Level

Depth (m)

Time Frame

DO (mg/L)

pH

Sal (ppt)

Temp (oC)

Turbidty (NTU)

Current Velocity (m/s)

Current Direction

CF

20210416

Cloudy

Moderate

Mid-Flood

Surface

1

8:00

10.23

8.26

28.98

24.45

7.77

0.179

SE