5 WATER QUALTY MONITORING

Monitoring Requirements

5.1 In accordance with the Updated EM&A Manual, impact water quality monitoring shall be carried out three days per week at all the designated monitoring stations during the construction period. The measurement periods are during the construction of channel specified in Table 4.1 of Updated EM&A Manual. The interval between two sets of monitoring shall not be less than 36 hours.

5.2 Replicate in-situ measurements of Dissolved Oxygen (DO), temperature, turbidity, pH, Suspended Solids (SS) and samples for Suspended Solids (SS), ammonia nitrogen, unionized ammonia, nitrate nitrogen and orthophosphate from each independent sampling event shall be collected to ensure a robust statistically interpretable database.

5.3 Appendix B shows the established Action and Limit Levels for the water quality monitoring work according to pre-construction ET’s Updated EM&A Manual and Baseline Water Quality Monitoring Report (KTN & FLN NDA).

Monitoring Parameters, Frequency

5.4 Table 5.1 summarized the monitoring parameters, monitoring periods and frequencies of the water quality monitoring.

Table 5.1 Water Quality Monitoring Parameters and Frequency

Parameters, unit	Depth	Frequency
· Temperature(°C) · pH(pH unit) · turbidity (NTU) · water depth (m) · salinity (ppt) · DO (mg/L and % of saturation) · SS (mg/L) · Ammonia Nitrogen (NH₃-N) (mg NH₃-N/L) · Unionized Ammonia (UIA) (mg/L) · Nitrate-nitrogen (NO₃-N) (mg NO₃^--N/L) · Ortho-phosphate (PO₄) (mg PO₄^3--P/L)	· 3 water depths: 1m below water surface, mid-depth and 1m above river bed. · If the water depth was less than 3m, mid-depth sampling only. · If water depth was less than 6m, mid-depth may be omitted.	3 days per week during construction of channel

Parameters, unit

Depth

Frequency

· Temperature(°C)

· pH(pH unit)

· turbidity (NTU)

· water depth (m)

· salinity (ppt)

· DO (mg/L and % of saturation)

· SS (mg/L)

· Ammonia Nitrogen (NH₃-N) (mg NH₃-N/L)

· Unionized Ammonia (UIA) (mg/L)

· Nitrate-nitrogen (NO₃-N) (mg NO₃^--N/L)

· Ortho-phosphate (PO₄) (mg PO₄^3--P/L)

· 3 water depths: 1m below water surface, mid-depth and 1m above river bed.

· If the water depth was less than 3m, mid-depth sampling only.

· If water depth was less than 6m, mid-depth may be omitted.

3 days per week during

construction of channel

Results and Observations

5.5 According to the Section 5.6.1.2 of approved EIA Report, the potential water quality impact during construction is due to the alternation of natural streams (i.e. channelization of Ma Tso Lung Stream and Siu Hang San Tsuen Stream) as these two streams are the ecological importance streams.

5.6 No construction of channel was carried out Ma Tso Lung Stream and Siu Hang San Tsuen Stream during the reporting month. Therefore, no water quality monitoring was conducted.