4.1 The baseline
monitoring schedule is provided in Appendix A. All the monitoring results are provided in Appendices C and D.
4.2
Summaries of the monitoring
result for the sensitive receivers are provided in Table A, B, C and D.
Note that Case 1 and 3 covered all six months of the baseline monitoring
locations, while Case 2 and 4 covered only the three months dry season period.
Table A Baseline
Water Quality Monitoring Results (in-situ, Case 1 and 3)
|
Station |
DO, surface & middle level (mg/L) |
DO, bottom level (mg/L) |
Turbidity, depth average (NTU) |
||||||
|
ave |
max |
min |
ave |
max |
min |
ave |
max |
min |
|
|
B10 |
6.5 |
8.9 |
4.8 |
6.1 |
8.7 |
4.4 |
3.8 |
6.4 |
1.8 |
|
B11 |
6.5 |
8.9 |
4.7 |
- |
- |
- |
3.6 |
6.2 |
2.0 |
|
B12 |
6.4 |
9.3 |
4.7 |
6.3 |
8.6 |
4.5 |
4.2 |
6.6 |
2.2 |
|
B13 |
6.4 |
9.3 |
4.5 |
6.2 |
9.2 |
4.1 |
4.6 |
7.5 |
1.5 |
|
B14 |
6.4 |
8.8 |
4.5 |
- |
- |
- |
4.6 |
7.9 |
1.8 |
|
B24 |
6.9 |
8.8 |
4.2 |
6.8 |
8.6 |
4.1 |
2.3 |
7.7 |
0.9 |
|
B25 |
6.9 |
8.4 |
4.0 |
6.8 |
8.5 |
4.1 |
2.7 |
12.0 |
0.3 |
|
B26 |
7.0 |
8.7 |
4.4 |
6.9 |
8.6 |
4.3 |
2.9 |
10.4 |
0.9 |
|
B30 |
7.1 |
9.5 |
5.6 |
- |
- |
- |
2.5 |
5.2 |
0.6 |
|
B31 |
7.2 |
8.9 |
5.5 |
- |
- |
- |
2.3 |
4.5 |
0.7 |
|
B32 |
7.1 |
9.3 |
5.4 |
- |
- |
- |
1.9 |
3.3 |
0.7 |
|
B33 |
6.9 |
8.9 |
5.5 |
6.8 |
8.8 |
4.6 |
2.4 |
4.9 |
1.0 |
|
B34 |
7.0 |
8.9 |
5.3 |
6.9 |
8.9 |
5.1 |
2.5 |
6.2 |
0.6 |
|
B35 |
7.0 |
9.0 |
5.5 |
6.8 |
8.9 |
5.0 |
2.5 |
4.2 |
0.6 |
|
B7 |
6.4 |
8.5 |
4.2 |
- |
- |
- |
4.9 |
9.5 |
2.0 |
|
B8 |
6.3 |
8.4 |
4.2 |
6.1 |
8.4 |
4.1 |
5.2 |
10.8 |
1.7 |
|
B9 |
6.5 |
9.3 |
4.7 |
6.3 |
8.8 |
4.3 |
4.1 |
7.5 |
1.8 |
|
EM1 |
6.7 |
8.9 |
4.1 |
6.6 |
8.6 |
4.1 |
2.4 |
4.7 |
0.6 |
|
EM2 |
6.8 |
8.9 |
4.2 |
6.7 |
8.9 |
4.1 |
2.6 |
4.2 |
0.8 |
|
EM3 |
6.9 |
9.0 |
4.3 |
6.8 |
8.9 |
4.5 |
3.7 |
11.9 |
0.9 |
|
F1 |
6.9 |
9.1 |
4.3 |
6.8 |
9.0 |
4.3 |
2.3 |
3.6 |
0.6 |
|
F4 |
6.6 |
9.0 |
4.7 |
6.4 |
8.4 |
4.3 |
3.9 |
8.2 |
1.3 |
|
F5 |
6.4 |
8.6 |
4.7 |
6.3 |
8.6 |
4.3 |
5.2 |
9.3 |
2.7 |
|
JM3 |
6.6 |
8.7 |
4.1 |
6.5 |
8.7 |
4.0 |
3.1 |
4.9 |
0.3 |
|
MM13 |
7.3 |
9.2 |
6.0 |
7.0 |
8.8 |
5.7 |
2.9 |
7.4 |
0.7 |
|
SM17 |
6.9 |
8.4 |
5.3 |
6.5 |
8.2 |
3.8 |
5.9 |
12.6 |
1.9 |
|
SM2 |
6.9 |
8.8 |
5.3 |
6.6 |
8.4 |
4.1 |
3.2 |
5.2 |
1.0 |
|
SM3 |
6.6 |
8.8 |
4.3 |
6.4 |
8.5 |
4.0 |
3.4 |
6.6 |
0.9 |
|
VM1 |
6.5 |
8.4 |
4.1 |
6.4 |
8.3 |
3.9 |
3.0 |
5.9 |
1.2 |
|
VM12 |
6.0 |
8.2 |
4.2 |
5.7 |
7.7 |
3.7 |
5.9 |
10.6 |
2.0 |
|
VM14 |
6.1 |
8.5 |
4.5 |
5.9 |
8.0 |
4.0 |
6.2 |
13.1 |
2.4 |
|
VM15 |
6.0 |
8.2 |
4.0 |
5.8 |
7.7 |
3.7 |
4.3 |
6.9 |
1.7 |
|
VM2 |
6.4 |
8.5 |
3.9 |
6.3 |
8.5 |
3.9 |
2.8 |
4.9 |
1.0 |
|
VM4 |
6.1 |
8.2 |
4.1 |
6.1 |
8.2 |
3.9 |
2.8 |
4.2 |
1.1 |
|
VM5 |
6.1 |
8.3 |
4.0 |
6.0 |
8.1 |
3.8 |
2.9 |
4.8 |
0.9 |
|
VM7 |
6.0 |
8.1 |
4.0 |
5.9 |
7.9 |
3.8 |
3.9 |
8.2 |
1.3 |
|
VM8 |
6.1 |
8.3 |
4.3 |
6.1 |
8.0 |
4.0 |
5.7 |
12.8 |
2.0 |
|
WM1 |
6.6 |
9.1 |
4.6 |
6.4 |
8.6 |
4.0 |
3.8 |
6.3 |
1.0 |
|
WM2 |
6.3 |
8.8 |
4.4 |
6.2 |
8.1 |
4.1 |
5.3 |
8.9 |
1.2 |
|
WM4 |
6.3 |
8.4 |
4.3 |
6.1 |
8.3 |
4.0 |
5.4 |
8.5 |
1.9 |
|
WSD10 |
6.4 |
8.6 |
4.0 |
6.3 |
8.4 |
3.9 |
3.2 |
6.1 |
1.0 |
|
WSD11 |
6.4 |
8.4 |
3.9 |
6.3 |
8.4 |
3.9 |
2.7 |
4.1 |
0.8 |
|
WSD12 |
6.7 |
9.0 |
4.2 |
6.5 |
8.9 |
3.6 |
2.6 |
6.0 |
1.4 |
|
WSD13 |
6.6 |
8.8 |
4.2 |
6.6 |
8.8 |
4.1 |
2.6 |
5.1 |
0.7 |
|
WSD15 |
6.4 |
8.5 |
3.9 |
6.4 |
8.4 |
3.8 |
3.2 |
5.8 |
0.8 |
|
WSD17 |
6.3 |
8.3 |
3.6 |
6.2 |
8.3 |
3.7 |
3.8 |
6.1 |
1.5 |
|
WSD18 |
5.9 |
7.4 |
3.9 |
5.7 |
7.4 |
3.7 |
4.4 |
7.3 |
1.8 |
|
WSD19 |
6.0 |
7.8 |
4.0 |
5.9 |
7.7 |
3.8 |
4.5 |
7.8 |
1.4 |
|
WSD20 |
6.2 |
8.4 |
4.5 |
6.2 |
8.0 |
4.3 |
4.0 |
6.4 |
1.8 |
|
WSD21 |
6.8 |
8.9 |
5.0 |
6.6 |
9.3 |
4.0 |
2.9 |
4.9 |
1.3 |
|
WSD22 |
6.0 |
7.9 |
4.0 |
6.0 |
7.9 |
3.9 |
3.4 |
5.0 |
1.1 |
|
WSD4 |
6.1 |
8.5 |
4.4 |
6.0 |
8.5 |
4.0 |
5.6 |
8.3 |
2.3 |
|
WSD5 |
6.0 |
8.1 |
4.3 |
5.8 |
8.1 |
3.9 |
6.3 |
10.0 |
2.5 |
|
WSD6 |
5.4 |
7.9 |
3.5 |
5.4 |
7.8 |
3.1 |
5.4 |
9.1 |
1.6 |
|
WSD7 |
5.8 |
7.9 |
3.7 |
5.8 |
7.8 |
3.7 |
4.7 |
8.1 |
1.9 |
|
WSD9 |
6.1 |
8.4 |
4.0 |
6.1 |
8.3 |
3.8 |
2.9 |
5.3 |
0.9 |
Table B Baseline Water
Quality Monitoring Results (in-situ, Case 2 and 4)
|
Station |
DO, surface & middle level (mg/L) |
DO, bottom level (mg/L) |
Turbidity, depth average (NTU) |
||||||
|
ave |
max |
min |
ave |
max |
min |
ave |
max |
min |
|
|
B10 |
7.7 |
8.9 |
6.5 |
7.6 |
8.7 |
6.5 |
2.8 |
4.5 |
1.8 |
|
B11 |
7.7 |
8.9 |
6.6 |
- |
- |
- |
2.4 |
2.9 |
2 |
|
B12 |
7.7 |
9.3 |
6.6 |
7.8 |
8.6 |
6.6 |
3.0 |
4.9 |
2.2 |
|
B13 |
7.6 |
9.3 |
6.4 |
7.5 |
9.2 |
6.3 |
3.2 |
5.6 |
1.5 |
|
B14 |
7.6 |
8.8 |
6.8 |
- |
- |
- |
4.0 |
5.8 |
1.8 |
|
B24 |
8.0 |
8.8 |
7.1 |
7.9 |
8.6 |
7.1 |
1.6 |
2.1 |
1.2 |
|
B25 |
7.9 |
8.4 |
7 |
7.8 |
8.5 |
7.0 |
1.4 |
1.8 |
0.7 |
|
B26 |
8.0 |
8.7 |
7.1 |
8.0 |
8.6 |
7.1 |
1.9 |
2.5 |
1.2 |
|
B7 |
7.7 |
8.5 |
6.5 |
- |
- |
- |
3.6 |
5 |
2 |
|
B8 |
7.5 |
8.4 |
6.5 |
7.4 |
8.4 |
6.4 |
3.4 |
4 |
1.7 |
|
B9 |
7.7 |
9.3 |
6.6 |
7.6 |
8.8 |
6.5 |
2.8 |
3.5 |
1.8 |
|
EM1 |
7.9 |
8.9 |
6.9 |
7.9 |
8.6 |
7.0 |
1.8 |
3 |
0.6 |
|
EM2 |
8.0 |
8.9 |
7 |
8.0 |
8.9 |
7.1 |
2.0 |
3.2 |
0.8 |
|
EM3 |
8.0 |
9 |
7 |
7.9 |
8.9 |
7.0 |
2.2 |
3.4 |
0.9 |
|
F1 |
8.0 |
9.1 |
7 |
8.0 |
9.0 |
7.0 |
1.5 |
2.2 |
0.6 |
|
F5 |
7.6 |
8.6 |
6.7 |
7.5 |
8.6 |
6.5 |
3.9 |
4.4 |
2.7 |
|
JM3 |
7.8 |
8.7 |
6.8 |
7.7 |
8.7 |
6.7 |
1.9 |
3.3 |
0.3 |
|
MM13 |
8.1 |
9.2 |
7.1 |
7.9 |
8.8 |
7.0 |
2.5 |
4 |
0.7 |
|
SM17 |
7.8 |
8.4 |
7.1 |
7.6 |
8.2 |
6.9 |
4.1 |
6.6 |
1.9 |
|
VM1 |
7.7 |
8.4 |
6.8 |
7.7 |
8.3 |
6.8 |
2.1 |
2.8 |
1.2 |
|
VM12 |
7.2 |
8.2 |
6.1 |
6.9 |
7.7 |
5.9 |
4.0 |
5.7 |
2 |
|
VM14 |
7.3 |
8.5 |
6.1 |
7.1 |
8.0 |
6.0 |
5.5 |
13.1 |
2.4 |
|
VM15 |
7.1 |
8.2 |
6.1 |
7.0 |
7.7 |
6.0 |
3.4 |
5.5 |
1.7 |
|
VM2 |
7.6 |
8.5 |
6.4 |
7.5 |
8.5 |
6.2 |
2.0 |
2.8 |
1 |
|
VM4 |
7.3 |
8.2 |
6.3 |
7.2 |
8.2 |
6.1 |
2.1 |
3 |
1.1 |
|
VM5 |
7.2 |
8.3 |
6.1 |
7.1 |
8.1 |
6.0 |
2.0 |
3 |
0.9 |
|
VM7 |
7.1 |
8.1 |
6.1 |
7.0 |
7.9 |
5.9 |
2.5 |
3.8 |
1.3 |
|
VM8 |
7.4 |
8.3 |
6.4 |
7.3 |
8.0 |
6.4 |
3.8 |
6.9 |
2 |
|
WSD10 |
7.6 |
8.6 |
6.4 |
7.5 |
8.4 |
6.5 |
2.4 |
4.2 |
1 |
|
WSD11 |
7.6 |
8.4 |
6.6 |
7.5 |
8.4 |
6.4 |
2.2 |
3.2 |
0.8 |
|
WSD12 |
7.9 |
9 |
6.9 |
7.8 |
8.9 |
6.9 |
1.9 |
2.9 |
1.4 |
|
WSD13 |
7.9 |
8.8 |
6.9 |
7.8 |
8.8 |
6.9 |
1.8 |
2.7 |
0.7 |
|
WSD15 |
7.7 |
8.5 |
6.7 |
7.6 |
8.4 |
6.7 |
2.2 |
4 |
0.8 |
|
WSD17 |
7.5 |
8.3 |
6.3 |
7.4 |
8.3 |
6.2 |
2.7 |
3.9 |
1.5 |
|
WSD18 |
6.8 |
7.4 |
6 |
6.8 |
7.4 |
5.8 |
2.8 |
4 |
1.8 |
|
WSD19 |
7.0 |
7.8 |
5.9 |
6.9 |
7.7 |
5.9 |
2.5 |
3.9 |
1.4 |
|
WSD20 |
7.3 |
8.4 |
6.2 |
7.3 |
8.0 |
6.4 |
3.5 |
5.6 |
1.8 |
|
WSD22 |
7.1 |
7.9 |
6.1 |
7.1 |
7.9 |
6.1 |
2.3 |
4.8 |
1.1 |
|
WSD5 |
7.2 |
8.1 |
6.1 |
7.1 |
8.1 |
6.0 |
4.6 |
6.1 |
2.5 |
|
WSD6 |
6.6 |
7.9 |
5.6 |
6.6 |
7.8 |
5.5 |
4.4 |
5.3 |
2.3 |
|
WSD7 |
6.9 |
7.9 |
5.9 |
6.8 |
7.8 |
5.8 |
3.5 |
5.3 |
1.9 |
|
WSD9 |
7.2 |
8.4 |
6 |
7.2 |
8.3 |
6.0 |
2.3 |
5.3 |
0.9 |
Table C Baseline Water
Quality Monitoring Results (E.coli,
Case 1 and 3)
|
Stations |
E.coli (cfu/100ml) |
Stations |
E.coli (cfu/100ml) |
||||
|
average |
max |
min |
average |
max |
min |
||
|
B10 |
649 |
3200 |
1 |
VM1 |
110 |
350 |
6 |
|
B11 |
589 |
2800 |
1 |
VM12 |
1889 |
16000 |
9 |
|
B12 |
482 |
2600 |
<1 |
VM14 |
605 |
2200 |
36 |
|
B13 |
464 |
2600 |
<1 |
VM15 |
1316 |
7100 |
24 |
|
B14 |
390 |
2500 |
<1 |
VM2 |
144 |
880 |
2 |
|
B24 |
47 |
610 |
<1 |
VM4 |
483 |
1500 |
20 |
|
B25 |
10 |
100 |
<1 |
VM5 |
1426 |
5900 |
12 |
|
B26 |
28 |
150 |
<1 |
VM7 |
1617 |
7200 |
1 |
|
B30 |
5 |
45 |
<1 |
VM8 |
5071 |
32000 |
6 |
|
B31 |
1 |
2 |
<1 |
WM1 |
691 |
7100 |
<1 |
|
B32 |
7 |
46 |
<1 |
WM2 |
986 |
4700 |
5 |
|
B33 |
3 |
11 |
<1 |
WM4 |
504 |
2500 |
<1 |
|
B34 |
7 |
36 |
<1 |
WSD10 |
140 |
740 |
2 |
|
B35 |
5 |
62 |
<1 |
WSD11 |
142 |
940 |
12 |
|
B7 |
399 |
1800 |
4 |
WSD12 |
47 |
500 |
<1 |
|
B8 |
709 |
3700 |
<1 |
WSD13 |
228 |
4000 |
<1 |
|
B9 |
533 |
3100 |
<1 |
WSD15 |
236 |
1500 |
20 |
|
EM1 |
161 |
4600 |
<1 |
WSD17 |
2029 |
43000 |
23 |
|
EM2 |
191 |
3700 |
<1 |
WSD18 |
2968 |
14000 |
26 |
|
EM3 |
13 |
110 |
<1 |
WSD19 |
2537 |
9600 |
15 |
|
F1 |
29 |
360 |
<1 |
WSD20 |
4079 |
26000 |
6 |
|
F4 |
1226 |
19000 |
2 |
WSD21 |
561 |
9100 |
<1 |
|
F5 |
347 |
3200 |
2 |
WSD22 |
1516 |
6700 |
120 |
|
JM3 |
130 |
3300 |
<1 |
WSD4 |
744 |
3100 |
9 |
|
MM13 |
5 |
140 |
<1 |
WSD5 |
774 |
2000 |
51 |
|
SM17 |
6 |
120 |
<1 |
WSD6 |
1173 |
6000 |
44 |
|
SM2 |
3 |
22 |
<1 |
WSD7 |
1474 |
4800 |
88 |
|
SM3 |
491 |
9200 |
<1 |
WSD9 |
806 |
4500 |
5 |
Notes:
-
For
conservative assessment, 1 cfu/100ml was adopted as
the lowest level in the average calculation if the tested result was below
reporting limit (<1).
Table D Baseline Water
Quality Monitoring Results (E.coli,
Case 2 and 4)
|
E.coli (cfu/100ml) |
Stations |
E.coli (cfu/100ml) |
|||||
|
average |
max |
min |
average |
max |
min |
||
|
B10 |
70 |
340 |
1 |
VM14 |
245 |
660 |
36 |
|
B11 |
60 |
220 |
1 |
VM15 |
1343 |
5500 |
86 |
|
B12 |
95 |
220 |
<1 |
VM2 |
62 |
170 |
2 |
|
B13 |
117 |
360 |
<1 |
VM4 |
363 |
1300 |
45 |
|
B14 |
58 |
320 |
<1 |
VM5 |
1579 |
5200 |
12 |
|
B24 |
2 |
10 |
<1 |
VM7 |
1759 |
7200 |
45 |
|
B25 |
2 |
4 |
<1 |
VM8 |
3176 |
14000 |
48 |
|
B26 |
26 |
150 |
<1 |
WSD10 |
69 |
130 |
2 |
|
B7 |
146 |
490 |
4 |
WSD11 |
64 |
160 |
12 |
|
B8 |
284 |
1800 |
<1 |
WSD12 |
25 |
67 |
<1 |
|
B9 |
140 |
800 |
<1 |
WSD13 |
288 |
4000 |
<1 |
|
EM1 |
24 |
130 |
<1 |
WSD15 |
168 |
600 |
20 |
|
EM2 |
14 |
56 |
<1 |
WSD17 |
784 |
3600 |
23 |
|
EM3 |
6 |
24 |
<1 |
WSD18 |
3776 |
14000 |
420 |
|
F1 |
13 |
56 |
<1 |
WSD19 |
2788 |
9600 |
170 |
|
F5 |
87 |
510 |
2 |
WSD20 |
3412 |
15000 |
32 |
|
JM3 |
51 |
120 |
<1 |
WSD22 |
1778 |
6700 |
270 |
|
MM13 |
1 |
1 |
<1 |
WSD5 |
414 |
1400 |
72 |
|
SM17 |
3 |
19 |
<1 |
WSD6 |
452 |
2000 |
44 |
|
VM1 |
91 |
300 |
6 |
WSD7 |
1148 |
3000 |
88 |
|
VM12 |
2341 |
16000 |
9 |
WSD9 |
634 |
2100 |
5 |
Notes:
-
For
conservative assessment, 1 cfu/100ml was adopted as
the lowest level in the average calculation if the tested result was below
reporting limit (<1).
Observations
4.1
During the baseline water quality monitoring period,
no observable pollution source was identified at all the designated monitoring
stations during the baseline monitoring period.
4.2
Since no observable pollution activity was observed
for all stations during sampling, the baseline monitoring results are
considered to be representative of the ambient water quality levels.
4.3
Normal Distribution (95% confidence interval) analysis was conducted to
identify the outliers from the monitoring results.
4.4
In order to determine the guideline for establishing
the Action/Limit
levels at the sensitive receivers, One Way Analysis of Variance (ANOVA) was applied to test the
differences of the baseline monitoring data between the water quality
monitoring locations under each individual Cases. The purpose of the analysis was to test the
following hypothesis:
H0: The data of the monitoring stations within a Case would have no significant difference.
H1: The data of the monitoring stations within a Case would have significant difference.
4.5
There are no
significant difference amongst the data of Turbidity for Case 3 and 4.
For Case 1 and 2, however, significant differences between the data were found.
Therefore the Action/Limit
level for these two cases of monitoring stations will be analysed in groups
instead. For Dissolved Oxygen, all Cases show no significant difference amongst
the data. The Action/Limit
level for this parameter will be assessed together within the same case.
4.6
The analysis results for Dissolved Oxygen and Turbidity with no significant differences are presented in Table 4.1a-b and 4.2a.
Table 4.1a
Summary of the Results of ANOVA (Dissolved
Oxygen, surface &
middle depth)
|
Dissolved Oxygen, surface &
middle depth |
Sample Size |
Degree of Freedom |
F-value |
P-value |
|
Case 1 |
429 |
35 |
1.1530 |
0.2577 |
|
Case 2 |
162 |
26 |
1.2291 |
0.2229 |
|
Case 3 |
144 |
11 |
0.2497 |
0.9930 |
|
Case 4 |
54 |
8 |
0.0282 |
1 |
Table 4.1b Summary of the Results of ANOVA (Dissolved
Oxygen, bottom depth)
|
Dissolved Oxygen, bottom depth |
Sample Size |
Degree of Freedom |
F-value |
P-value |
|
Case 1 |
356 |
29 |
0.9130 |
0.5988 |
|
Case 2 |
141 |
23 |
1.4411 |
0.1064 |
|
Case 3 |
105 |
8 |
0.2142 |
0.9877 |
|
Case 4 |
33 |
5 |
0.0790 |
0.9950 |
Table 4.2a
Summary of the Results of ANOVA (Turbidity, Case 3 and 4)
|
Turbidity |
Sample Size |
Degree of Freedom |
F-value |
P-value |
|
Case
3 |
140 |
11 |
0.5727 |
0.8481 |
|
Case
4 |
54 |
8 |
1.6544 |
0.1364 |
4.7
Since the Turbidity data for Case 1 and
2 (the monitoring
stations other than gradient stations and control stations) were found to have
significant differences, a second hypothesis is proposed for the two parameters
as follow:
H0: The data of the monitoring stations in specific groups within Case 1 and 2 would have no
significant difference (Shown in Table
4.2b-c).
H2: The data of the monitoring stations in specific groups within Case 1 and 2 would have
significant difference (Shown in Table
4.2b-c).
4.8
The second ANOVA results shown that there are no significant differences among the data of the grouped
monitoring stations. The
outcome of this analysis will be adopted to set the Turbidity’s Action and Limit levels for Case 1 and
2 under these groupings.
The analysis results for Turbidity are shown in Table 4.2b-c.
Table 4.2b
Summary of the Results of ANOVA (Turbidity, Case 1)
|
Turbidity (Case 1 ) |
Sample Size |
Degree of Freedom |
F-value |
P-value |
|
B30, B31, B32, B33, B34, B35
, WSD21, F4 |
92 |
7 |
1.8972 |
0.0801 |
|
B10, B11, B12, B13, B14, B7,
B8, B9, F5 |
104 |
8 |
0.7721 |
0.6281 |
|
B24, B25, B26, F1 |
45 |
3 |
0.3770 |
0.7700 |
|
WSD17, WSD9, WSD20, WSD18, WSD19,
WSD7, WSD6 |
84 |
6 |
2.1746 |
0.0544 |
|
WSD10, WSD11, WSD12, WSD13,
WSD15, WSD22 |
68 |
5 |
1.6351 |
0.1640 |
|
WSD4, WSD5 |
24 |
1 |
0.5680 |
0.4591 |
Table 4.2c
Summary of the Results of ANOVA (Turbidity, Case 2)
|
Turbidity (Case 2 ) |
Sample Size |
Degree of Freedom |
F-value |
P-value |
|
B10, B11, B12, B13, B14, B7,
B8, B9, F5 |
54 |
8 |
1.6544 |
0.1364 |
|
B24, B25, B26, F1 |
24 |
3 |
1.1111 |
0.3680 |
|
WSD7, WSD9, WSD10, WSD11,
WSD12, WSD13, WSD15, WSD17, WSD18, WSD19, WSD20, WSD22 |
72 |
11 |
1.4479 |
0.1759 |
|
WSD5, WSD6 |
12 |
1 |
0.0457 |
0.8349 |
4.9
For the E.coli parameter, the
Action and Limit level will be established based on the result of the individual
monitoring stations. The guideline for the establishment of the E.coli’s Action/Limit level is shown
in Table 4.4 and 4.5.
Guidelines for Establishment of Action and Limit Levels
4.10 Formulated
on the basis of the ANOVA results, the monitoring locations with no significant
difference between their sampled parameters will be grouped together for the
evaluation of the Action and Limit Levels. All outliers were removed before the
calculation of the Action and Limit Levels for Marine Water Quality. An
exceedance will be considered to be valid when either the monitoring results
exceed the established Action/Limit levels which are derived from the baseline
data, or exceed 20% (Action level) or 30% (Limit level) of the monitoring
results from the control stations.
4.11 The Action
and Limit levels guideline are established and
shown in Tables 4.3 to 4.5. For reference, the
Water Quality Objectives established for various Water Control Zones in the EIA
study (CE 43/2005, Section
6.20) indicated that the target limit for E.
coli, calculated as the geometric mean of all samples collected in one
calendar year, was 610 cfu/100ml for Fish Culture
Subzones and Secondary Contact Recreation Subzones. The level of 610 cfu/100ml is also the criteria value in which the gazetted
beaches would be closed for poor water quality if exceeded. The Dissolved
Oxygen levels were set at 4 mg/l for averaged depth and 2 mg/l for bottom
depth. Also noted that the gradient station are used to assist in the identification of
the source of potential impact at the sensitive receiver (e.g. beach locations)
and was therefore excluded from the Action/Limit level Guidelines, along with the control stations.
Table
4.3 Guidelines
for Establishment of Action and Limit Levels for In-situ Monitoring Parameters
|
Parameter (unit) |
Water Depth |
Action Level |
Limit Level |
|
DO (mg/L) |
Surface and
Middle |
5%-ile
of baseline data |
4 mg/L or 1%-ile of baseline data |
|
Bottom |
5%-ile of
baseline data |
2 mg/L or 1%-ile of baseline data |
|
|
Turbidity (NTU) |
Depth average |
95%-ile of baseline data or 120% of upstream
control station’s turbidity at the same tide of the same day |
99%-ile of baseline data or 130% of turbidity
at the upstream control station at the same tide of the same day |
Table
4.4 Guidelines
for Establishment of Limit Levels for E.
coli for WSD Intakes
|
Parameter (unit) |
Water Depth |
Limit Level |
|
E. coli (cfu/100ml) |
Depth average |
20,000 cfu/100ml |
Remark:
-
The
limit level is based on Water Supplies Department’s criteria regarding the
target limit of the flushing water.
Table
4.5 Guidelines
for Establishment of Action and Limit Levels for Laboratory Testing Parameter
for Monitoring Stations Other than WSD Intakes, Gradient Stations and Control
Stations
|
Parameter (unit) |
Water Depth |
Action Level |
Limit Level |
|
E. coli (cfu/100ml) |
Depth average (geometric mean) |
E.
coli of 95%-ile of baseline data |
E.
coli of 99%-ile of baseline data or 610 cfu/100ml |
Established Action and Limit Levels
4.12 Following the
criteria as shown in Table 4.3 to Table 4.5, the Action and Limit Levels
for water quality impact monitoring have been established and shown in Tables 4.6a, 4.6b, 4.7, 4.8a and 4.8b.
Table 4.6a Calculated Action
and Limit Levels for In-situ Monitoring Parameters
(Dissolved Oxygen)
|
Case |
Monitoring Stations |
Water Depth |
Action Level |
Limit Level |
|
Case 1 |
All Case 1’s
stations |
Surface and
Middle |
4.2 |
4(1) |
|
Bottom |
4.0 |
3.7 |
||
|
Case 2 |
All Case 2’s
stations |
Surface and
Middle |
6.1 |
5.8 |
|
Bottom |
6.0 |
5.7 |
||
|
Case 3 |
All Case 3’s
stations |
Surface and
Middle |
4.5 |
4.1 |
|
Bottom |
4.1 |
3.8 |
||
|
Case 4 |
All Case 4’s
stations |
Surface and
Middle |
6.5 |
6.5 |
|
Bottom |
6.4 |
6.3 |
Notes:
1)
4
mg/L was selected as the limit levels, since the 1 percentile of the DO
baseline data were lower than the recommended limit level of 4 mg/L.
- For DO,
non-compliance of the water quality limits occurs when monitoring result is
lower than the limit levels.
Table
4.6b Calculated
Action and Limit Levels for In-situ Monitoring Parameters
(Turbidity)
|
Case |
Monitoring Stations |
Water Depth |
Action Level(1) |
Limit Level(2) |
|
Case 1 |
B30, B31, B32, B33, B34, B35
, WSD21, F4 |
Depth average |
4.3 |
6.2 |
|
B10, B11, B12, B13, B14, B7,
B8, B9, F5 |
7.2 |
7.9 |
||
|
B24, B25, B26, F1 |
5.0 |
6.9 |
||
|
WSD17, WSD9, WSD20, WSD18, WSD19,
WSD7, WSD6 |
7.3 |
8.9 |
||
|
WSD10, WSD11, WSD12, WSD13,
WSD15, WSD22 |
4.9 |
5.5 |
||
|
WSD4, WSD5 |
9.2 |
9.8 |
||
|
Case 2 |
B10, B11, B12, B13, B14, B7,
B8, B9, F5 |
Depth average |
4.9 |
5.7 |
|
B24, B25, B26, F1 |
2.2 |
2.4 |
||
|
WSD7, WSD9, WSD10, WSD11,
WSD12, WSD13, WSD15, WSD17, WSD18, WSD19, WSD20, WSD22 |
5.1 |
5.4 |
||
|
WSD5, WSD6 |
5.7 |
6.0 |
||
|
Case 3 |
All Case 3’s
stations |
Depth average |
7.3 |
7.9 |
|
Case 4 |
All Case 4’s
stations |
Depth average |
4.9 |
5.7 |
Notes:
-
For turbidity, non-compliance of water quality
limits occurs when monitoring result is higher than the limit levels.
1)
Baseline data or 120% of
upstream control station’s turbidity at the same tide of the same day
2)
Baseline data or 130% of
upstream control station’s turbidity at the same tide of the same day
Table 4.7 Limit
Levels for E. coli for WSD Flushing
Water Intakes
|
Parameter (unit) |
Water Depth |
Limit Level |
|
E. coli (cfu/100ml) |
Depth average |
20,000 cfu/100ml |
Notes:
-
The
limit level is based on the Water Supplies Department’s Criteria regarding the
target limit of the flushing water.
-
For E. coli,
non-compliance of water quality limits occurs when monitoring result is higher
than the limit levels.
Table 4.8a Action
and Limit Levels for E. coli at
Monitoring Stations other than WSD Flushing Water Intakes, Gradient Stations
and Control Stations (Case 1 and 3)
|
Parameter (unit) |
Monitoring locations |
Water Depth |
Action Level (cfu/100ml) |
Limit Level (cfu/100ml) |
|
E. coli (cfu/100ml) |
B10 |
Geometric mean |
610* |
610* |
|
B11 |
610* |
610* |
||
|
B12 |
610* |
610* |
||
|
B13 |
610* |
610* |
||
|
B14 |
610* |
610* |
||
|
B24 |
61 |
86 |
||
|
B25 |
13 |
17 |
||
|
B26 |
54 |
61 |
||
|
B30 |
6 |
6 |
||
|
B31 |
1 |
2 |
||
|
B32 |
13 |
25 |
||
|
B33 |
3 |
4 |
||
|
B34 |
10 |
14 |
||
|
B35 |
6 |
9 |
||
|
B7 |
414 |
475 |
||
|
B8 |
610* |
610* |
||
|
B9 |
610* |
610* |
||
|
F1 |
35 |
48 |
||
|
F4 |
610* |
610* |
||
|
F5 |
610* |
610* |
Notes:
-
For E. coli,
non-compliance of water quality limits occurs when monitoring result is higher
than the limit levels.
-
For
conservative assessment, 1 cfu/100ml was adopted as
the lowest level in the calculation if the tested result was below reporting
limit (<1).
* The Action and
Limit Level were set as 95%-tile and 99%-tile of the baseline data if they were
lower than the criteria’s level of 610cfu/100ml.
Table 4.8b Action
and Limit Levels for E. coli at
Monitoring Stations other than WSD Flushing Water Intakes, Gradient Stations
and Control Stations (Case 2 and 4)
|
Parameter (unit) |
Monitoring locations |
Water Depth |
Action Level (cfu/100ml) |
Limit Level (cfu/100ml) |
|
E. coli (cfu/100ml) |
B10 |
Geometric mean |
31 |
35 |
|
B11 |
195 |
215 |
||
|
B12 |
146 |
150 |
||
|
B13 |
223 |
223 |
||
|
B14 |
13 |
15 |
||
|
B24 |
5 |
6 |
||
|
B25 |
3 |
3 |
||
|
B26 |
58 |
62 |
||
|
B7 |
448 |
482 |
||
|
B8 |
101 |
105 |
||
|
B9 |
333 |
370 |
||
|
F1 |
9 |
9 |
||
|
F5 |
258 |
298 |
Notes:
-
For E. coli,
non-compliance of water quality limits occurs when monitoring result is higher
than the limit levels.
-
For
conservative assessment, 1 cfu/100ml was adopted as
the lowest level in the calculation if the tested result was below reporting
limit (<1).
4.13 Actions prior to and during the Temporary Sewage Bypass will be carried
out in accordance with the Action Plan as shown in Appendix F.