Action and Limit Levels for Water Quality

Calculated Action and Limit Levels (Ebb Tide)

Monitoring Station

Upstream Control Station

DO, Surface & Middle (mg/L)

DO, Bottom (mg/L)

Turbidity (NTU)

SS (mg/L)

Ebb

Action

Limit

Action

Limit

Action

Limit

Action

Limit

MW1

MC1

3.88

3.29

3.90

3.35

13.29

or 120% of upstream control station's Tby at the same tide of the same day

18.37

or 130% of upstream control station's Tby at the same tide of the same day

11.5

or 120% of upstream control station's SS at the same tide of the same day

20.0

or 130% of upstream control station's SS at the same tide of the same day

MW2

MW3

MW4

MW5

MW6

WFCZF1

4.91

4.24

4.66

4.03

16.70

23.12

13.1

14.1

Notes:

· All the figures given in the table are used for reference only and the EPD may amend the figures whenever it is considered necessary.

Calculated Action and Limit Levels (Flood Tide)

Monitoring Station	Upstream Control Station	DO, Surface & Middle (mg/L)		DO, Bottom (mg/L)		Turbidity (NTU)				SS (mg/L)
	Flood	Action	Limit	Action	Limit	Action		Limit		Action		Limit
MW1	Nil	5.20	4.72	5.00	4.65	14.55	or 120% of upstream control station's Tby at the same tide of the same day	28.86	or 130% of upstream control station's Tby at the same tide of the same day	18.6	or 120% of upstream control station's SS at the same tide of the same day	23.4	or 130% of upstream control station's SS at the same tide of the same day
MW2
MW3						11.50		12.80		9.9		11.5
MW4
MW5	MR5					14.55		28.86		18.6		23.4
MW6	MR6
WFCZF1	Nil	5.01	5.00	4.69	4.55	20.07		21.61		17.1		18.1

Notes: All the figures given in the table are used for reference only and the EPD may amend the figures whenever it is considered necessary.