River Water Quality in Hong Kong in 2002

Results for 2002 from the River Water Quality Monitoring Programme of the Environmental Protection Department

Monitoring Section Water Policy and Planning Group Environmental Protection Department The Government of the Hong Kong Special Administrative Region

2003

河 River Water Quality in Hong Kong in 2002

River Water Quality in Hong Kong in 2002

Report number : EPD/TR5/03

Date : November 2003

Report written by : Cecilia P.W. WONG

Work done by : Cecilia P.W. WONG, S.W. LEE Y.W. LAU, W.H. WONG and C.K. TANG

Work supervised by : Cathie S.W. KUEH

Cover designed by : Y.W. LAU

Security classification : Unrestricted

Note: The information contained in this publication can be used freely for study, research and training purposes subject to acknowledgement of the source. Use of the information for purposes other than those stated above requires prior permission of the Director of Environmental Protection.

河 River Water Quality in Hong Kong in 2002

CONTENTS

ACKNOWLEDGEMENTS K – 1

DISCLAIMER K – 2

SUMMARY OF RIVER WATER QUALITY IN 2002 S – 1

1. INTRODUCTION 1 – 1

2. TOLO HARBOUR AND CHANNEL WATER CONTROL ZONE 2 – 1

2.1 Shing Mun River 2 – 1 2.2 Lam Tsuen River 2 – 3 2.3 Tai Po River 2 – 3 2.4 Tai Po Kau Stream 2 – 4 2.5 Shan Liu and Tung Tze Streams 2 – 5 2.6 Tolo Harbour Sewerage Master Plan 2 – 6

3. SOUTHERN WATER CONTROL ZONE 3 – 1

3.1 Mui Wo River 3 – 1

4. PORT SHELTER WATER CONTROL ZONE 4 – 1

4.1 Ho Chung River 4 – 1 4.2 Sha Kok Mei Stream 4 – 1 4.3 Tai Chung Hau Stream 4 – 2 4.4 Port Shelter Sewerage Master Plan 4 – 3

5. JUNK BAY WATER CONTROL ZONE 5 – 1

5.1 Tseng Lan Shue Stream 5 – 1

河 River Water Quality in Hong Kong in 2002 C - 1

CONTENTS

6. DEEP BAY WATER CONTROL ZONE 6 – 1

6.1 River Indus 6 – 1 6.2 River Beas 6 – 2 6.3 River Ganges 6 – 2 6.4 Yuen Long Creek 6 – 3 6.5 Kam Tin River 6 – 4 6.6 Tin Shui Wai Nullah 6 – 5 6.7 Fairview Park Nullah 6 – 6 6.8 Ngau Hom Sha, Sheung Pak Nai, Pak Nai, Ha Pak Nai, 6 – 7 Tai Shui Hang and Tsang Kok Streams 6.9 Pollution control measures in the Deep Bay catchment 6 – 8

7. NORTH WESTERN WATER CONTROL ZONE 7 – 1

7.1 Tuen Mun River 7 – 1 7.2 Tung Chung River 7 – 2

8. WESTERN BUFFER WATER CONTROL ZONE 8 – 1

8.1 Pai Min Kok (Anglers’) Stream 8 – 1

9. VICTORIA HARBOUR WATER CONTROL ZONE 9 – 1

9.1 Sam Dip Tam Stream 9 – 1 9.2 Kau Wa Keng Stream 9 – 1 9.3 Kai Tak Nullah 9 – 2

河 River Water Quality in Hong Kong in 2002 C - 2

LIST OF FIGURES

Figure Title Page I Percentages of river monitoring stations in Hong Kong showing S – 3 long-term water quality trends in different parameters

II Compliance of Water Quality Objectives (WQOs) in the inland waters S – 4 of Hong Kong from 1986 to 2002

III Compliance of Hong Kong’s rivers and streams with Water Quality S – 5 Objectives (WQOs) in 2002

IV Major inland waters in Hong Kong and the Water Quality Index (WQI) S – 6 gradings of 82 monitoring stations in 2000 to 2002

V Water Quality Index (WQI) of inland waters of Hong Kong from 1986 S – 7 to 2002

VI Water Control Zones (WCZs) in Hong Kong S – 8

VII Livestock waste prohibition, control and restriction areas in Hong Kong S – 9

VIII Sewerage Master Plan areas in Hong Kong S – 10

2.1 Water Quality Index (WQI) of Shing Mun River and its tributaries 2 –14

2.2 Water Quality Index (WQI) of Shing Mun River and its tributaries 2 – 15 (continued)

2.3 Water Quality Index (WQI) of Lam Tsuen River and its tributaries 2 – 16

2.4 Water Quality Index (WQI) of Lam Tsuen River (continued) and Tai Po 2 – 17 River and their tributaries

河 River Water Quality in Hong Kong in 2002 C - 3

LIST OF FIGURES

Figure Title Page 2.5 Water Quality Index (WQI) of minor streams in the Tolo Harbour and 2 – 18 Channel Water Control Zone

3.1 Water Quality Index (WQI) of Mui Wo River and its tributaries 3 – 5

4.1 Water Quality Index (WQI) of Ho Chung River and its tributaries 4 – 7

4.2 Water Quality Index (WQI) of Sha Kok Mei Stream and its tributaries 4 – 8

4.3 Water Quality Index (WQI) of Tai Chung Hau Stream and its tributaries 4 – 9

5.1 Water Quality Index (WQI) of Tseng Lan Shue Stream and its 5 – 5 tributaries

6.1 Water Quality Index (WQI) of the River Indus and its tributaries 6 – 20

6.2 Water Quality Index (WQI) of the River Beas and its tributaries 6 – 21

6.3 Water Quality Index (WQI) of the River Ganges and its tributaries 6 – 22

6.4 Water Quality Index (WQI) of Yuen Long Creek and Kam Tin River 6 – 23 and their tributaries

6.5 Water Quality Index (WQI) of Tin Shui Wai Nullah and Fairview Park 6 – 24 Nullah and their tributaries

6.6 Water Quality Index (WQI) of minor streams in the Deep Bay Water 6 – 25 Control Zone

6.7 Water Quality Index (WQI) of minor streams in the Deep Bay Water 6 – 26 Control Zone (continued)

河 River Water Quality in Hong Kong in 2002 C - 4

LIST OF FIGURES

Figure Title Page 7.1 Water Quality Index (WQI) of Tuen Mun River and its tributaries 7 – 6

7.2 Water Quality Index (WQI) of Tung Chung River and its tributaries 7 – 7

8.1 Water Quality Index (WQI) of Pai Min Kok (Anglers’) Stream and its 8 – 5 tributaries

9.1 Water Quality Index (WQI) of Sam Dip Tam Stream and its tributaries 9 – 9

9.2 Water Quality Index (WQI) of Kau Wa Keng Stream 9 – 10

9.3 Water Quality Index (WQI) of Kai Tak Nullah 9 – 11

河 River Water Quality in Hong Kong in 2002 C - 5

LIST OF TABLES

Table Title Page I Summary of river water quality monitoring stations and sampling 1 – 2 frequencies in 2002

IIA – C Summary of the parameters and analytical methods in the river water 1 – 3 quality monitoring programme

IIIA – B Summary of key Water Quality Objectives (WQOs) for different 1 – 6 watercourses in the river monitoring programme

IV Water Quality Index (WQI) for inland waters of Hong Kong 1 – 8

2.1A – C River water quality trends in the Tolo Harbour and Channel Water 2 – 7 Control Zone based on the results of the Seasonal Kendall Test

2.2 Pollution load reductions in the river catchments of the Tolo Harbour 2 – 10 and Channel Water Control Zone as at the end of 2002

2.3A Summary of water quality monitoring data for Shing Mun River in 2 – 11 2002

2.3B Summary of water quality monitoring data for Shing Mun River, Tai 2 – 12 Po River and minor streams in the Tolo Harbour & Channel Water Control Zone in 2002

2.3C Summary of water quality monitoring data for Lam Tsuen River in 2 – 13 2002

3.1 River water quality trends in the Southern Water Control Zone based 3 – 2 on the results of the Seasonal Kendall Test

河 River Water Quality in Hong Kong in 2002 C - 6

LIST OF TABLES

Table Title Page 3.2 Pollution load reduction in the Mui Wo River catchment of the 3 – 3 Southern Water Control Zone as at the end of 2002

3.3 Summary of water quality monitoring data for Mui Wo River in 2002 3 – 4

4.1 River water quality trends in the Port Shelter Water Control Zone 4 – 4 based on the results of the Seasonal Kendall Test

4.2 Pollution load reductions in the river catchments of the Port Shelter 4 – 5 Water Control Zone as at the end of 2002

4.3 Summary of water quality monitoring data for Ho Chung River, Sha 4 – 6 Kok Mei Stream and Tai Chung Hau Stream in 2002

5.1 River water quality trends in the Junk Bay Water Control Zone based 5 – 2 on the results of the Seasonal Kendall Test

5.2 Pollution load reduction in the Tseng Lan Shue Stream catchment of 5 – 3 the Junk Bay Water Control Zone as at the end of 2002

5.3 Summary of water quality monitoring data for Tseng Lan Shue 5 – 4 Stream in 2002

6.1A – C River water quality trends in the Deep Bay Water Control Zone based 6 – 10 on the results of the Seasonal Kendall Test

6.2A – D Pollution load reductions in the river catchments of the Deep Bay 6 – 13 Water Control Zone as at the end of 2002

6.3A Summary of water quality monitoring data for the River Indus, the 6 – 17 River Beas and the River Ganges in 2002

河 River Water Quality in Hong Kong in 2002 C - 7

LIST OF TABLES

Table Title Page 6.3B Summary of water quality monitoring data for Yuen Long Creek, 6 – 18 Kam Tin River and Tin Shui Wai Nullah in 2002

6.3C Summary of water quality monitoring data for Fairview Park Nullah 6 – 19 and minor streams in the Deep Bay Water Control Zone in 2002

7.1 River water quality trends in the North Western Water Control Zone 7 – 3 based on the results of the Seasonal Kendall Test

7.2 Pollution load reduction in the Tuen Mun River catchment of the 7 – 4 North Western Water Control Zone as at the end of 2002

7.3 Summary of water quality monitoring data for Tuen Mun River and 7 – 5 Tung Chung River in 2002

8.1 River water quality trends in the Western Buffer Water Control Zone 8 – 2 based on the results of the Seasonal Kendall Test

8.2 Pollution load reduction in the Pai Min Kok (Anglers’) Stream 8 – 3 catchment of the Western Buffer Water Control Zone as at the end of 2002

8.3 Summary of water quality monitoring data for Pai Min Kok 8 – 4 (Anglers’) Stream in 2002

9.1A - B River water quality trends in the Victoria Harbour Water Control 9 – 4 Zone based on the results of the Seasonal Kendall Test

9.2 Pollution load reductions in the river catchments of the Victoria 9 – 6 Harbour Water Control Zone as at the end of 2002

河 River Water Quality in Hong Kong in 2002 C - 8

LIST OF TABLES

Table Title Page 9.3A Summary of water quality monitoring data for Sam Dip Tam Stream 9 – 7 and Kau Wa Keng Stream in 2002

9.3B Summary of water quality monitoring data for Kai Tak Nullah in 9 – 8 2002

河 River Water Quality in Hong Kong in 2002 C - 9 ACKNOWLEDGEMENTS

We acknowledge the following parties for their contributions to the river water quality report:

Government Laboratory and

Waste Policy and Services Group, Environmental Protection Department

for undertaking chemical and bacteriological analyses of river samples.

Local Control Offices, Environmental Protection Department

for providing pollution loading data and information on pollution control measures.

Sewerage Infrastructure Planning Group, Environmental Protection Department

for updating the progress of sewerage master plans and other sewerage projects.

河 River Water Quality in Hong Kong in 2002 K - 1 DISCLAIMER

Whilst the Government of the Hong Kong Special Administrative Region (“the Government”) endeavours to ensure the accuracy of the information in this report, the Government (including its officers and employees) makes no warranty, statement or representation, expressed or implied, with respect to accuracy, completeness, or usefulness of the information contained herein, and in so far as permitted by law, shall not have any legal liability or responsibility (including liability for negligence) for any loss, damage, injury and death which may result, whether directly or indirectly, from the supply or use of such information. Users are responsible for making their own assessments of all information contained in this publication before acting on it.

河 River Water Quality in Hong Kong in 2002 K - 2 Summary of River Water Quality in 2002 “excellent” WQI and a 99% or 100% WQO Summary of River compliance (Table 1).

Table 1 Ten top water quality rivers in Hong Kong in Water Quality in 2002

Overall 2002 Watercourses WCZ WQO (River/Stream) * Compliance WQI (%) Ha Pak Nai 100 E The Environmental Protection Tai Shui Hang 100 E Outer Pak Nai 100 E Department (EPD) has worked towards Deep Bay Sheung Pak Nai 100 E restoring the health of Hong Kong inland Tsang Kok 100 E waters since the mid 80s. With continuous enforcement efforts and gradual provision of Port Ho Chung 100 E public sewer, there have been long-term Shelter Tai Chung Hau 100 E improvements in the 35 rivers and streams Tolo monitored in the territory. Harbour Tai Po Kau 100 E and Tung Tze 100 G As in 2001, 87% of the 82 monitoring Channel stations showed an increase in dissolved Southern Mui Wo 99 E oxygen (DO); and more than 60% of the *G and E stand for “good” and “excellent” WQI grading respectively stations showed decreases in suspended solids (SS), aggregate organics and nutrients (Figure In 2002, 74% of the river monitoring I) in 2002. An additional 8% of the stations stations attained a “good” or “excellent” (WQI) showed significant decreases in E. coli grading, showing a slight increase of 2% bacteria. comparing with 2001 (Figure V). However, there was one monitoring station in the “very Similar to 2001, the overall Water bad” category, i.e. KT2 in Kam Tin River. It Quality Objective (WQO) compliance with could be attributed to the pollution from the pH, SS, DO, 5-day Biochemical Oxygen unsewered villages, illegal discharges from livestock farms and increased livestock Demand (BOD5) and Chemical Oxygen Demand (COD) objectives was 83% in 2002 population in the catchment.

(Figure II). The compliance with the pH and The bacterial levels in most of the rivers DO objectives was above 90%; whereas the were still quite high, in particular the major compliance with the BOD objective was the 5 rivers in Inner Deep Bay and Tuen Mun River. lowest at 66% (Figure III). This was mainly due to faecal contamination

from unsewered villages, livestock wastes or The Water Quality Indices (WQIs) of the both. Only nine out of 82 river stations (11%) rivers and streams monitored in 2002, as well in the territory achieved the E. coli WQO in as in 2001 and 2000 are shown on the maps in 2002. Figure IV. There were nine rivers and streams in the territory achieving full compliance with Overall, the seven major rivers in the the five key WQOs in 2002. They were Tai Po inner Deep Bay catchment had the poorest Kau Stream, Tung Tze Stream, Ho Chung water quality in the territory. In 2002, the River, Tai Chung Hau Stream and five minor WQI of their most downstream stations were streams in the Outer Deep Bay. Most of these between “fair” and “very bad”. The watercourses have also sustained an compliance with the E. coli objective was 0% “excellent” WQI in the last three years. The and their averaged WQO compliance rate for nine watercourses were among the top ten the five key parameters was 51%, showing a rivers in 2002 achieving a “good” or further decline of 3% from that in 2001.

河 River Water Quality in Hong Kong in 2002 S - 1 Summary of River Water Quality in 2002

Among the major watercourses in inner Deep Bay, Kam Tin River and Fairview Park Nullah showed the most obvious deterioration. Their WQIs were downgraded from “fair” or “bad” to “bad” or “very bad”. In 2002 the overall WQO compliance of Kam Tin River and Fairview Park Nullah were 27% and 47% respectively showing a decrease of 12% from that in 2001. The deterioration may be mainly attributed to the unsewered villages and increased pollution from livestock farms.

In order to reduce pollution in the rivers and streams, continued efforts would be made in enforcing the Water Pollution Control Ordinance (Figure VI) and Waste Disposal Ordinance, and implementing the revised Livestock Waste Control Scheme (Figure VII). In addition, through the implementation of the Environmental Impact Assessment Ordinance, environmental impacts of major projects would also be minimised.

To tackle the problem of unsewered villages and to cater for future population growth and developments, many sewerage master plans (SMPs) (Figure VIII) have been updated to provide additional sewer and sewage treatment capacities. Comprehensive programmes have been implemented to connect village houses and unsewered premises to the newly built public sewers.

However, implementation of the SMPs suffers slippage of one or more years due to the current financial constraints. These include the sewerage projects in Tolo Harbour, Port Shelter, and North District. In addition, the sewerage programme in Tuen Mun was also delayed due to strong opposition from local residents. If the sewerage projects can proceed as scheduled, there should be major improvements in the inland water quality around the early 2010s when the sewerage network is fully operational.

河 River Water Quality in Hong Kong in 2002 S - 2 Long-term water quality trends 2.4 Zinc -93.9 -28.0 Total phosphorus 1.2 Ortho- -85.4 -53.7 phosphate 1.2 1.2 -92.7 -46.3 nitrogen Nutrients Total Kjeldahl Metals 46.3 -18.3 Nitrate- -28.0 nitrogen 3.7 1.2 -69.5 -14.6 nitrogen 1.2 < 0.05.< 2. Positive values indicate trends,increasing negative values indicate decreasing trends. p 24.4 -20.7 -14.6 Sulphide Ammonia 1.2 Solids -65.9 -22.0 Suspended 1.2 COD grease & Oil Aluminium Cadmium Chromium Copper Lead E.coli -37.8 -85.4 Aggregate organics different parameters different 5 3. Blue indicates improvement, red indicates deterioration. 1. The results are based on Seasonal Kendall Test, significant at 86.6 BOD Oxygen -86.6 Dissolved Notes : Notes 0 0 50

Figure IFigure in trends quality water showing long-term Kong in Hong stations monitoring river of Percentages -50 -50

100 100 -100 % of stations of % % of stations of % -100

河 River Water Quality in Hong Kong in 2002 S-3 河 100 River Water QualityWater inHongRiver Kongin2002

83 82 83 80 78 76 77

72 70 70 68 Compliance of WaterCompliance QualityObjectives of (WQOs) 66

61 61 62 60 58 WQO Compliance

49 (By percentage % of monitoring stations) of monitoring % percentage (By 49 50 47

40 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year S-4 Figure II Compliance of Water Quality Objectives (WQOs) in the inland waters of Hong Kong from 1986 to 2002 河 River Water QualityWater inHongRiver Kongin2002 Overall 1 Suspended Dissolved Chemical 5-day Biochemical Water Control pH Compliance Watercourses Solids Oxygen Oxygen Demand Oxygen Demand Zones 0% 100% 0% 100% 0% 100% 0% 100% 0% 100% (%) Shing Mun River 2 90 Lam Tsuen River 90 Tolo Harbour Tai Po River 97 and Channel Tai Po Kau Stream 100 Shan Liu Stream 97 Tung Tze Stream 100 Southern Mui Wo River 99 Ho Chung River 100 Port Shelter Sha Kok Mei Stream 98 Tai Chung Hau Stream 100 Compliance with WaterQuality Objectives (WQOs) in 2002 Junk Bay Tseng Lan Shue Stream 85 River Indus 55 River Beas 59 River Ganges 59 Yuen Long Creek 43 Kam Tin River 3 27 Ha Pak Nai Stream 100 Deep Bay Tai Shui Hang Stream 100 Pak Nai Stream 100 Sheung Pak Nai Stream 100 Ngau Hom Sha Stream 85 Tsang Kok Stream 100 Fairview Park Nullah 47 Tin Shui Wai Nullah 68 Tuen Mun River 78 North Western Tung Chung River 96 Western Buffer Pai Min Kok (Anglers') Stream 97 Sam Dip Tam Stream 96 Victoria Harbour KauWaKengStream 93

4 Average Compliance 96 82 93 78 66 83

Notes : 1. Overall compliance is the mean compliance rate of the five WQOs. 2. Overall compliance of Shing Mun River is the mean compliance rate of 6 watercourses in the river system. 3. Absence of a bar indicates 0% compliance. 4. Average compliance is the mean compliance rate of all river monitoring stations. S-5 Figure III Compliance of Hong Kong's rivers and streams with Water Quality Objectives (WQOs) in 2002 河 River Water QualityWater inHongRiver Kongin2002 SHENZHEN Water Quality Index N Excellent Good 16 Fair 17

Bad 18 Inland watercourses 22º30’ Very Bad 1. Tseng Lan Shue Stream 32 2. Ho Chung River 11 3. Tai Chung Hau Stream 12 4. Sha Kok Mei Stream 23 5. Shing Mun Main Channel (Shing Mun River) 22 33 15 6. Fo Tan Nullah (Shing Mun River) 24 7. Siu Lek Yuen Nullah (Shing Mun River) 8. Kwun Yam Shan Stream (Shing Mun River) 14 25 9. Tai Wai Nullah (Shing Mun River) 26 13 10. Tin Sum Nullah (Shing Mun River) 11. Shan Liu Stream

29 27 inland Major andwaters WQI monitoring of stations NEW TERRITORIES 6 12. Tung Tze Stream 5 28 4 13. Tai Po Kau Stream 7 14. Tai Po River 30 9 15. Lam Tsuen River 20 3 21 16. River Ganges 17. River Indus 10 8 18. River Beas 19. Kau Wa Keng Stream 2 19 20. Sam Dip Tam Stream 35 21. Pai Min Kok (Anglers’) Stream 22º20’ KOWLOON 22. Kam Tin River 1 23. Yuen Long Creek 24. Ngau Hom Sha Stream 25. Sheung Pak Nai Stream 26. Pak Nai Stream 27. Ha Pak Nai Stream 28. Tai Shui Hang Stream 34 29. Tsang Kok Stream HONG KONG 30. Tuen Mun River ISLAND 31. Mui Wo River 31 LANTAU 32. Fairview Park Nullah 33. Tin Shui Wai Nullah ISLAND 34. Tung Chung River 35. Kai Tak Nullah 22o10’ N 0 5 10km 114º10’ 114º20’ 114º00’ S–6a Figure IV Major inland waters in Hong Kong and the Water Quality Index (WQI) gradings of 82 monitoring stations in 2002 ►2001 ►2000 河 River Water QualityWater inHongRiver Kongin2002 SHENZHEN Water Quality Index N Excellent Good 16 Fair 17

29 27 inland Major andwaters WQI monitoring of stations NEW TERRITORIES 6 12. Tung Tze Stream 5 28 4 13. Tai Po Kau Stream 7 14. Tai Po River 30 9 15. Lam Tsuen River 20 3 21 16. River Ganges 17. River Indus 10 8 18. River Beas 19. Kau Wa Keng Stream 2 19 20. Sam Dip Tam Stream 35 21. Pai Min Kok (Anglers’) Stream 22º20’ KOWLOON 22. Kam Tin River 1 23. Yuen Long Creek 24. Ngau Hom Sha Stream 25. Sheung Pak Nai Stream 26. Pak Nai Stream 27. Ha Pak Nai Stream 28. Tai Shui Hang Stream 34 29. Tsang Kok Stream HONG KONG 30. Tuen Mun River ISLAND 31. Mui Wo River 31 LANTAU 32. Fairview Park Nullah 33. Tin Shui Wai Nullah ISLAND 34. Tung Chung River 35. Kai Tak Nullah 22o10’ N 0 5 10km 114º10’ 114º20’ 114º00’ S–6b Figure IV Major inland waters in Hong Kong and the Water Quality Index (WQI) gradings of 82 monitoring (cont.) stations in 2001 ►2000 ►2002 河 River Water QualityWater inHongRiver Kongin2002 SHENZHEN Water Quality Index N Excellent Good 16 Fair 17

29 27 inland Major andwaters WQI monitoring of stations NEW TERRITORIES 6 12. Tung Tze Stream 5 28 4 13. Tai Po Kau Stream 7 14. Tai Po River 30 9 15. Lam Tsuen River 20 3 21 16. River Ganges 17. River Indus 10 8 18. River Beas 19. Kau Wa Keng Stream 2 19 20. Sam Dip Tam Stream 35 21. Pai Min Kok (Anglers’) Stream 22º20’ KOWLOON 22. Kam Tin River 1 23. Yuen Long Creek 24. Ngau Hom Sha Stream 25. Sheung Pak Nai Stream 26. Pak Nai Stream 27. Ha Pak Nai Stream 28. Tai Shui Hang Stream 34 29. Tsang Kok Stream HONG KONG 30. Tuen Mun River ISLAND 31. Mui Wo River 31 LANTAU 32. Fairview Park Nullah 33. Tin Shui Wai Nullah ISLAND 34. Tung Chung River 35. Kai Tak Nullah 22o10’ N 0 5 10km 114º10’ 114º20’ 114º00’ S–6c Figure IV Major inland waters in Hong Kong and the Water Quality Index (WQI) gradings of 82 monitoring (cont.) stations in 2000 ►2001 ►2002 河

River Water QualityWater inHongRiver Kongin2002 Year 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 (Total number of monitoring stations) (47) (54) (57) (68) (76)(75)(75) (86) (86) (86) (86) (82) (82) (81) (82) (82) (82)

37.2 38.5 33.8 47.4 43.6 2.7 50.0 28.4 35.0 37.7 32.4 19.7 9.5 Excellent 8.5 18.4

9.3 12.7 43.3

25.5 29.7 23.0 31.2 22.4 30.8 28.2 Good 18.4 18.2 22.1 16.7 14.3 22.1 26.9 21.8 30.8

21.3 20.4 20.6 21.1 21.1 20.3 20.8 23.0 Fair 18.9 18.2 16.9 16.7 17.9 18.2 16.7 15.4 12.8

9.0 11.7 10.3 11.5 11.5 14.3 14.8 13.0 13.0 12.8 19.2 17.1 18.9 18.9 22.2 Bad 25.4 23.7 6.4 Water QualityIndex (WQI) 2.5 5.1 1.3 Water Quality Index Water Quality 11.7 10.4 14.3 10.8 (By percentage % of monitoring stations) monitoring % of percentage (By 16.2 25.0 21.6 Very Bad 25.5 13.1 31.4 27.0 S-7 Figure V Water Quality Index (WQI) of inland waters of Hong Kong from 1986 to 2002 Water Control Zones (WCZs) in Hong Kong First Appointed Day Appointed 6 N 10.1 Phase I10.2 Phase II10.3 Phase III 1.11.94 1.9.95 1.4.96 Water Control Zones (WCZs) Zones Water Control 1. Tolo Harbour Channel & 2. Southern3. Port Shelter4. Junk Bay5. Bay Deep 6. BayMirs 1.4.87 7. Western North 8. Western Buffer9. Buffer Eastern 1.8.88 1.8.89 1.8.89 1.12.90 1.4.92 1.6.93 1.12.90 1.6.93 1S. Tolo1S. Harbour Supplementary Supplementary Southern 2S. 10. Victoria Harbour 1.6.93 Supplementary Southern Second 2SI. 1.6.93 Western North 7S. Supplementary 1.11.99 1.11.99 3 9 4 1S 1S 1 10.1 2SI 2S ISLAND 10.2 HONG KONG 10.3 KOWLOON 1S 10.1 8 SHENZHEN NEW TERRITORIES 2 5 7 2S LANTAU ISLAND LANTAU 2SI Figure VI Water Control Zones (WCZs) in Hong Kong in Hong Zones (WCZs) Control VI Water Figure 7S

河 River Water Quality in Hong Kong in 2002 S-8 河 River Water QualityWater inHongRiver Kongin2002 SHENZHEN

N Livestock waste Livestock waste prohibition, controland restriction areas NEW TERRITORIES

KOWLOON

HONG KONG ISLAND Prohibition Areas LANTAU ISLAND

Restriction Areas

Control Areas S-9

Figure VII Livestock waste prohibition, control and restriction areas in Hong Kong 河 River Water QualityWater inHongRiver Kongin2002

Shenzhen

3 6 11 4

4 5 9 1 inHong Kong areas Plan Master Sewerage Sewerage Master Plans Commencement Completion

16 1. East Kowloon 1992 2001 2. Hong Kong Island South 1990 1999 3. Tolo Harbour 1993 2012 7 4. Tsuen Wan, Kwai Chung & Tsing Yi 1994 1998 12 Ting Kau & Sham Tseng 1996 2008 5. North West Kowloon 1992 2003 13 10 6. Port Shelter 1993 2010 15 15 7. Central, Western & Wan Chai West 1996 2007 2 8. Yuen Long & Kam Tin 1999 2010 9. North & South Kowloon 1995 2008 10. Chai Wan & Shau Kei Wan 1995 1997 11. Tuen Mun 1995 2009 12. Wan Chai East & North Point 1998 2008 15 13. Aberdeen, Ap Lei Chau & Pok Fu Lam 1998 2008 14. North District 1999 2012 15. Outlying Islands 1999 2010 15 16. Tseung Kwan O (Stages I & II) 2007 2009 0510km S-10 Figure VIII Sewerage Master Plan areas in Hong Kong Chapter 1 Introduction Water Control Zones (WCZs) and three supplementary WCZs (Table III). Compliance 1. Introduction with the WQOs is calculated based on 5 key parameters: pH, suspended solids, DO, BOD5 and COD.

1.3.2 The annual WQO compliance of a 1.1 River Monitoring Programme river is the average compliance rate of all monitoring stations in the river expressed in 1.1.1 The Environmental Protection terms of percentages; whereas the overall Department (EPD) has set up a programme to annual compliance rate in the territory is the monitor the water quality of rivers and average compliance of all river stations in the streams in Hong Kong since its establishment territory monitored during the year. in 1986. In 2002, monitoring was conducted once every month at 82 stations located in 35 inland watercourses in the territory (Table I). 1.4 Water Quality Index (WQI)

1.1.2 The water quality data collected 1.4.1 Water Quality Index (WQI) from the monitoring programme reflect the indicates organic pollution in a river and general health of the rivers. They enable us to reflects the ability of the river to support evaluate the effectiveness of the pollution aquatic life. It is calculated based on three abatement measures implemented, and parameters: DO, BOD5 and ammonia-nitrogen provide a basis for formulating future water (Table IV). Using the system, a river is graded quality management strategies. as “excellent”, “good”, “fair”, “bad” or “very bad”.

1.2 Water Quality Parameters 1.5 Long-term Water Quality Trends 1.2.1 A comprehensive range of physical, chemical and biological parameters are 1.5.1 To determine whether there is a analysed in the river monitoring programme. sustained improvement or deterioration in the These include flow, dissolved oxygen (DO), river, long-term water quality trends are aggregate organics (5-day Biochemical calculated using the non-parametric Seasonal Oxygen Demand (BOD5), Chemical Oxygen Kendall Test based on 10 or more years of Demand (COD), oil and grease), nutrients monitoring data. The test indicates whether (nitrogen and phosphorus), metals and faecal there is a significant increase, decrease or bacteria. Six physico-chemical parameters are absence of a trend in each river water quality measured in the field; while over 40 chemical parameters. and microbiological analyses are conducted in the Government Laboratory (http://www.info.gov.hk/govlab) and EPD’s 1.6 Pollution Loading laboratory (Table II). 1.6.1 The water quality of a river is 1.3 Compliance with Water Quality directly affected by the amount of pollutants entering the river. In order to assess the effect Objectives (WQOs) of pollution abatement measures on water quality, information on the organic pollution 1.3.1 To maintain the health of Hong load reduction in the major river systems in Kong’s rivers and streams, EPD has terms of kg BOD/day is also reported. established a set of WQOs for each of the ten

河 River Water Quality in Hong Kong in 2002 1 - 1 Chapter 1 Monitoring stations & sampling frequencies Table I Summary of river water quality monitoring stations and sampling frequencies in 2002

Water No. of Sampling Control Watercourse Monitoring station monitoring frequency Zone station

Shing Mun River Shing Mun Main Channel TR19I 1 Fo Tan Nullah TR17, TR17L 2 Siu Lek Yuen Nullah TR23A, TR23L 2 Kwun Yam Shan Stream KY1 1 Tolo Tai Wai Nullah TR19, TR19A, TR19C 3 Harbour Tin Sum Nullah TR20B 1 Monthly and Lam Tsuen River TR12, TR12B, TR12C, TR12D, TR12E, 9 Channel TR12F, TR12G, TR12H, TR12I Tai Po River TR13 1 Tai Po Kau Stream TR14 1 Shan Liu Stream TR4 1 Tung Tze Stream TR6 1

Southern Mui Wo River MW1, MW2, MW3, MW4, MW5 5 Monthly

Ho Chung River PR1, PR2 2 Port Sha Kok Mei Stream PR5, PR6 2 Monthly Shelter Tai Chung Hau Stream PR7, PR8 2

Junk Bay Tseng Lan Shue Stream JR3, JR6, JR11 3 Monthly

River Indus IN1, IN2, IN3 3 River Beas RB1, RB2, RB3 3 River Ganges GR1, GR2, GR3 3 Yuen Long Creek YL1, YL2, YL3, YL4 4 Kam Tin River KT1, KT2 2 Tin Shui Wai Nullah TSR1, TSR2 2 Fairview Park Nullah FVR1 1 Deep Bay Monthly Deep Bay streams Ha Pak Nai Stream DB1 1 Tai Shui Hang Stream DB2 1 Pak Nai Stream DB3 1 Sheung Pak Nai Stream DB5 1 Ngau Hom Sha Stream DB6 1 Tsang Kok Stream DB8 1

North Tuen Mun River TN1, TN2, TN3, TN4, TN5, TN6 6 Monthly Western Tung Chung River TC1, TC2, TC3 3

Western Pai Min Kok (Anglers’) AN1, AN2 2 Monthly Buffer Stream

Sam Dip Tam Stream TW1, TW2, TW3 3 Monthly Victoria Kau Wa Keng Stream KW3 1 Monthly Harbour Kai Tak Nullah KN1, KN4, KN5, KN7 4 Monthly KN2, KN3 2 3-monthly

Total 35 - 82 -

河 River Water Quality in Hong Kong in 2002 1 - 2 Chapter 1 Water quality parameters and analytical methods Table IIA Summary of the parameters and analytical methods in the river water quality monitoring programme

Reporting Parameter Unit Analytical Method 1 Analysed by Purpose Limit

1. Physical and aggregate properties

Conductivity 1 µS/cm

Dissolved oxygen 0.1 mg/L Multi-parameter water quality data logger, Show general model YSI-6820 EPD conditions of the pH 0.1 pH unit (on-site measurement) river.

Water temperature 0.1 °C Measure rate of Electromagnetic flow meter, river flow which Flow 1 L/s model Flo-mate 2000 EPD relates to dilution (on-site measurement) and dispersion of pollutants. Total suspended In-house method WC-IN-19, based on APHA2 0.5 mg/L solids 20ed 2540 D

In-house method WC-IN-9, based on APHA Government Total solids 0.5 mg/L Indicate the 20ed 2540 B Laboratory amount of solids in the water, In-house method WC-IN-9, based on APHA Total volatile solids 0.5 mg/L opacity of the 20ed 2540 E river. Multi-parameter water quality data logger, Turbidity 0.1 NTU model YSI-6820 EPD (on-site measurement)

2. Aggregate organics 5-day Biochemical Oxygen Demand 1 mg/L In-house method based on APHA 18ed 5210 B EPD (BOD5) Measure organic Chemical Oxygen In-house method WH-OA-3 (A) & (B), based pollutants and 2 mg/L 3 Demand (COD) on ASTM D1252-88 A & B (CODCr ) oxygen demanding Total Organic In-house method WC-IN-22, based on APHA Government 1 mg/L materials as well Carbon (TOC) 20ed 5310 B Laboratory as oil and grease. In-house method WC-IN-7, based on APHA Oil and grease 0.5 mg/L 20ed 5520 C (IR)

3. Faecal bacteria cfu/100mL (cfu: Indicate faecal E. coli 1 colony In-house method4, membrane filtration with contamination of forming CHROMagar Liquid E.coli-coliform culture EPD river by animal unit) broth wastes and domestic sewage. Faecal coliforms 1 cfu/100mL

Reference notes: 1. Mention of brand names of commercial products does not constitute or imply endorsement or recommendation by the Environmental Protection Department. 2. APHA - American Public Health Association: Standard Methods for the Examination of Water and Wastewater. 3. ASTM - Annual Book of American Society for the Testing and Materials Standards, Vol. 11.01 & 11.02. 4. i) Ho, B.S.W. and Tam, T.Y. (1997). Enumeration of E. coli in environmental waters and wastewater using a chromogenic medium. Wat. Sci. Tech., 35, 409-413. ii) DoE and DHSS (1983). “The bacteriological examination of drinking water supplies 1982. Report on Public Health and Medical Subjects No. 71. Methods for the Examination of Waters and Associated Materials”. Department of Environment, Department of Health and Social Security, Public Health Laboratory Service, H.M.S.O. London. 河 River Water Quality in Hong Kong in 2002 1 - 3 Chapter 1 Water quality parameters and analytical methods Table IIB Summary of the parameters and analytical methods in the river water quality monitoring programme (continued)

Reporting Parameter Unit Analytical Method Analysed by Purpose Limit

4. Nutrients and inorganic constituents

Nitrogen

Ammonia-nitrogen In-house method WC-IN-2, based on ASTM 0.005 mg/L (NH3-N) D3590-89 B (FIA)

Nitrite-nitrogen In-house method WC-IN-4, based on APHA 0.002 mg/L - (NO2-N) 20ed 4500-NO2 B (FIA)

Nitrate-nitrogen In-house method WC-IN-4, based on APHA 0.002 mg/L - (NO3-N) 20ed 4500-NO3 F & I (FIA) Measure the amount of plant Total Kjeldahl In-house method WC-IN-1 & 2, based on Government nutrients and the nitrogen 0.05 mg/L ASTM D3590-89 B (FIA) & APHA 20ed Laboratory extent of (soluble; soluble & 4500-N A&D (FIA) eutrophication in particulate) the water. Phosphorus

Ortho-phosphate as In-house method WC-IN-3, based on ASTM phosphorus 0.002 mg/L D515-88 B (FIA) (PO4-P)

Total phosphorus In-house method WC-IN-1 & 3, based on (soluble; soluble & 0.02 mg/L ASTM D515-88 B (FIA) & APHA 20ed particulate) 4500-P G (FIA)

Other inorganic constituents

Molybdate-reactive In-house method WC-IN-5, based on APHA 0.05 mg/L silica 20ed 4500-SiO2 C&E (FIA)

In-house method WC-IN-8(A), based on Cyanide 0.01 mg/L ASTM D4374-93 (FIA, amperometric)

In-house method WH-OA-6, based on BS 6068, Section 2.23 (1986) (Colorimetric) & Reflect anoxic Anionic surfactants In-house method WC-IN-24, based on Abbott, state of the rivers, 0.05 mg/L as well as (as Manoxol OT) D.C. “Analyst”, Vol.87, p.286(1962) & S. Government pollution caused Motomizu et al., “Analyst” Vol.113, Laboratory p.747(1988) (FIA) by detergents and other inorganic In-house method WC-IN-18(A), based on chemicals. Fluoride 0.2 mg/L APHA 20ed 4500-F- C & G (Ion Selective Electrode) and ASTM D1179-93 (FIA)

Free hydrogen In-house method WC-IN-17, based on APHA 0.01 mg/L sulphide 20ed 4500S2- D (Colorimetric)

Sulphide In-house method WC-IN-17, based on APHA (soluble; soluble & 0.02 mg/L 20ed 4500S2- D (Colorimetric) particulate) Reference notes: 1. Mention of brand names of commercial products does not constitute or imply endorsement or recommendation by the Environmental Protection Department. 2. APHA - American Public Health Association: Standard Methods for the Examination of Water and Wastewater. 3. ASTM - Annual Book of American Society for the Testing and Materials Standards, Vol. 11.01 & 11.02.

河 River Water Quality in Hong Kong in 2002 1 - 4 Chapter 1 Water quality parameters and analytical methods Table IIC Summary of the parameters and analytical methods in the river water quality monitoring programme (continued)

Reporting Parameter Unit Analytical Method Analysed by Purpose Limit

5. Algal biomass

In house method WC-IN-6, based on APHA Chlorophyll-a 0.2 mg/m3 20ed 10200H 2 (spectrophotometric) Indicate the Government amount of algal Laboratory biomass in river In house method WC-IN-6, based on APHA water. Pheo-pigment 0.2 mg/m3 20ed 10200H 2 (spectrophotometric)

6. Metals

Aluminium 50 µg/L

Antimony 1 µg/L

Arsenic 1 µg/L

Barium 1 µg/L

Beryllium 1 µg/L

Boron 50 µg/L

Cadmium 0.1 µg/L

Chromium 1 µg/L

Copper 1 µg/L Determine toxic metal pollution of In-house method WC-ME-7, based on USEPA Government Iron 50 µg/L the river caused Method 6020A (ICP-MS) Laboratory by industrial Lead 1 µg/L discharges.

Manganese 10 µg/L

Mercury 1 µg/L

Molybdenum 2 µg/L

Nickel 1 µg/L

Silver 1 µg/L

Thallium 1 µg/L

Vanadium 2 µg/L

Zinc 10 µg/L Reference notes: 1. Mention of brand names of commercial products does not constitute or imply endorsement or recommendation by the Environmental Protection Department. 2. APHA - American Public Health Association: Standard Methods for the Examination of Water and Wastewater. 3. ASTM - Annual Book of American Society for the Testing and Materials Standards, Vol. 11.01 & 11.02.

河 River Water Quality in Hong Kong in 2002 1 - 5 Chapter 1 Chapter 河

River WaterQualit Table IIIA Summary of key Water Quality Objectives (WQOs) for different watercourses in the river monitoring programme

pH BOD5 COD SS* DO E. coli WCZ Subzone (pH unit) (mg/L) (mg/L) (mg/L) (mg/L) (cfu/100mL) >= and <= <= <= <= >= <= Shing Mun (A) 5 30 1000a y Shing Mun (C) inHon 6.5 8.5 20 Shing Mun (F) 3 15 0a Shing Mun (H)

g a

Kon 5 30 1000 Shing Mun (I) 6.0 9.0 25 a g Tolo Harbour and Lam Tsuen (D) 3 15 in 2002 0 6.5 8.5 20 Key Water Quality Objectives (WQOs) for inlandwaters Channel Tai Po (C) Other inland waters except Shing Mun (B), 5 30 1000a (D), (E), (G), Lam 6.0 9.0 25 4 Tsuen (C) and Tai Po (A), (B) Tolo Harbour Whole zone 3 15 b Supplementary 1 6.5 8.5 20 Mui Wo (C) Mui Wo (E) Southern Other inland waters 5 30 610c except Mui Wo (A), 6.0 9.0 25 (B), (D), (F) * : SS is calculated based on annual median. a: E. coli level is calculated as the running median of the 5 most recent consecutive samples taken at intervals between 7 and 21 days (or 14 and 42 days). b : E. coli level is calculated as the geometric mean of the 5 most recent consecutive samples taken at intervals between 7 and 21 days. c: E. coli level is calculated as the geometric mean of all samples collected in one calendar year. d: E. coli level is calculated as the running median of the 5 most recent consecutive samples taken at intervals between 7 and 21 days. 1 -6 Chapter 1 Chapter 河

River WaterQualit Table IIIB Summary of key Water Quality Objectives (WQOs) for different watercourses in the river monitoring programme

pH BOD5 COD SS* DO E. coli WCZ Subzone (pH unit) (mg/L) (mg/L) (mg/L) (mg/L) (cfu/100mL) >= and <= <= <= <= >= <=

Ho Chung (A) 6.5 8.5 c

y Port Shelter 610

inHon Other inland waters 5 30 25 6.0 9.0 Junk Bay Inland waters 1000d g Indus Kon Beas g d in 2002 Ganges 315 0 Key Water Quality Objectives (WQOs) for inlandwaters Yuen Long & Kam Tin 6.5 8.5 Deep Bay (Upper) 20 Yuen Long & Kam Tin 4 (Lower) 5 30 Other inland waters 6.0 9.0 Tuen Mun (C) 6.5 8.5 3 15 1000d Other inland waters North Western except Tuen Mun (A), (B) 6.0 9.0 5 30 25 Western Buffer Other inland waters Victoria Harbour 1000b Inland waters (Phase One)

* : SS is calculated based on annual median. a: E. coli level is calculated as the running median of the 5 most recent consecutive samples taken at intervals between 7 and 21 days (or 14 and 42 days). b : E. coli level is calculated as the geometric mean of the 5 most recent consecutive samples taken at intervals between 7 and 21 days. c: E. coli level is calculated as the geometric mean of all samples collected in one calendar year. d: E. coli level is calculated as the running median of the 5 most recent consecutive samples taken at intervals between 7 and 21 days. 1 -7 Chapter 1 Water Quality Index (WQI) Table IV Water Quality Index (WQI) for inland waters of Hong Kong

The Water Quality Index (WQI) is a numerical value used to denote, on the basis of monitoring data, the general quality of a river. It reflects the extent of organic pollution and indicates the river's ability to support aquatic life. The WQI is calculated based on three key parameters: dissolved oxygen, 5-day Biochemical Oxygen Demand (BOD5) and ammonia-nitrogen. The measurements of these parameters are evaluated using the following table:

No. of points Dissolved oxygen BOD5 Ammonia-nitrogen awarded (% saturation) (mg/L) (mg/L)

1 91 – 110 < 3 < 0.5

71 – 90 2 3.1 – 6.0 0.5 – 1.0 111 – 120

51 – 70 3 6.1 – 9.0 1.1 – 2.0 121 – 130

4 31 – 50 9.1 – 15.0 2.1 – 5.0

5 < 30 or >130 > 15.0 > 5.0

All three parameters have equal weighting and the final score, i.e. annual WQI, is the sum of points of the three parameters calculated based on the averages of 12 months' data. The WQI values range from 3 to 15, corresponding to the following water quality conditions.

WQI Water quality condition 3.0 – 4.5 Excellent 4.6 – 7.5 Good 7.6 – 10.5 Fair

10.6 – 13.5 Bad

13.6 – 15.0 Very Bad

河 River Water Quality in Hong Kong in 2002 1 – 8 Chapter 2 Tolo Harbour and Channel Water Control Zone

2.1.3 Similar to 2001, the Water Quality 2. Tolo Harbour Index (WQI) of Shing Mun River remained “good” or “excellent” in 2002 (Figures 2.1 and Channel and 2.2) with long-term improvements in the dissolved oxygen (DO), organic pollutant and Water Control Zone toxic metal parameters (Tables 2.1A-B).

Improving trend of BOD5 in Tai Wai Nullah (TR19) 2.1 Shing Mun River 20

(mg/L) 10

BOD 5

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

2.1.4 Shing Mun Main Channel is a popular waterway for boating. Since 1993, it

has maintained a “good” WQI with a gradual 2.1.1 The Shing Mun River has a 2 improvement in the bacteriological quality. catchment area of 37 km with 5 major tributaries: Tin Sum, Tai Wai, Kwun Yam E. coli level in

Shan, Siu Lek Yuen and Fo Tan Nullahs. Shing Mun Main Channel (TR19I) 100,000

2.1.2 Since the declaration of the Tolo

Harbour and Channel Water Control Zone

(WCZ) in 1987, livestock waste pollution in 10,000

(cfu/100mL) the catchment of Shing Mun River has been largely eliminated. The removal of 93% of the E. coli organic pollutants (Table 2.2) from the river 1,000 catchment has resulted in a significant improvement in the compliance of the Water 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Quality Objectives (WQO) from 40% in 1987 Year to 90% in 2002.

WQO compliance of Shing Mun River 2.1.5 Tin Sum Nullah is the most upstream tributary of Shing Mun River. It has Shing Mun River sustained an “excellent” water quality in 2002 and fully complied with the WQOs including WQO % Compliance the E.coli objective. The Kwun Yam Shan 1987 2001 2002 Stream and Tai Wai Nullah also have attained pH 87 90 83 Suspended solids 11 100 100 an “excellent” or “good” WQI. A reduction in Dissolved oxygen 72 98 99 E. coli was noted in Tai Wai Nullah over the COD 12 94 96 last decade. BOD5 17 69 72 Overall 40 90 90

河 River Water Quality in Hong Kong in 2002 2 - 1 Chapter 2 Tolo Harbour and Channel Water Control Zone

E. coli level in Improving trend of Chromium in Tai Wai Nullah (TR19) Fo Tan Nullah (TR17, TR17L) 1,000,000 700

600

100,000 500 400

(cfu/100mL) 10,000 300

(µg/L)Cr coli E. 200 1,000 100 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 0 Year

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2.1.6 The Siu Lek Yuen Nullah has Year attained a “good” to “excellent” WQI since the early 90s. Although some improvement has been made, the E.coli level in the nullah Reducing pollution in the Shing Mun River remained high mainly due to the impact of unsewered villages in the catchment. 2.1.8 To further reduce pollution loading and improve water quality of Shing Mun E. coli level in River, sewerage construction and riverbed Siu Lek Yuen Nullah (TR23A) 1,000,000 improvement works are currently being implemented:

100,000 New public sewers for 26 villages in

(cfu/100mL) Shatin were built and over 74% of the 10,000 village houses were connected to the E. coli sewer by the end of 2002. Further works 1,000 for 9 villages in the river catchment have

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 commenced and is expected to be Year completed in 2004.

2.1.7 In 2002, the WQI of the Fo Tan Bioremediation and dredging of Nullah was “good” with continued reduction contaminated river sediments are in E. coli and toxic metal levels. currently being carried out under the project Environmental Improvement of Shing Mun River. After the completion E. coli level in of Stage 1 works in December 2002, the Fo Tan Nullah (TR17L) 1,000,000 Stage 2 works has commenced in May 2003 and is scheduled for completion in 2006. 100,000

(cfu/100mL) 10,000

E. coli

1,000

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

河 River Water Quality in Hong Kong in 2002 2 - 2 Chapter 2 Tolo Harbour and Channel Water Control Zone

2.2 Lam Tsuen River 2.2.3 The mean E. coli concentrations at the upstream stations of the river (TR12D, H, G) were relatively low between 100 and 400 cfu/100mL (Table 2.3C). However, they increased markedly further downstream and reached 14,000 cfu/100mL in the lower tidal channel (TR12I). Unsewered villages and contaminated runoff were the major pollution sources in the lower part of the river.

2.3 Tai Po River

2.2.1 The Lam Tsuen River catchment covers an area of 18.6 km2, 85% of which are within the water-gathering ground. Since the enforcement of water pollution legislation in the late 80s, there has been a substantial increase of DO and decrease of organic pollutants (BOD5) in the river.

Improving trend of BOD5 in Lam Tsuen River (TR12F) 15

(mg/L)

5 5 BOD

0 2.3.1 The Tai Po River joins Lam Tsuen 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year River near the Kwong Fuk Estate. In 2002, it 2.2.2 In 2002, the Lam Tsuen River has has achieved a 97% compliance with the key maintained a “good” or “excellent” WQI WQOs and a “good” WQI (Figure 2.4). (Figures 2.3 and 2.4) and a WQO compliance of 90%. 2.3.2 Although the Tai Po River has shown long-term improvements in many WQO compliance of Lam Tsuen River water quality parameters including DO,

nitrogen, phosphorus and metals, the E. coli Lam Tsuen River level in the river remained very high at 33,000 WQO % Compliance cfu/100mL (Table 2.3B). This could be due to 1987 2001 2002 the discharges from unsewered villages in the pH 95 99 96 catchment. Suspended solids 71 100 78 Dissolved oxygen 97 98 99 COD 80 94 91 BOD5 77 85 87 Overall 84 95 90

河 River Water Quality in Hong Kong in 2002 2 - 3 Chapter 2 Tolo Harbour and Channel Water Control Zone

Improving trend of Total Phosphorus in Tai Po River (TR13) 2.4 Tai Po Kau Stream 2.0

1.5

1.0

(mg/L) TP(SP) 0.5

0.0

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

WQO compliance of Tai Po River

Tai Po River 2.4.1 After 15 years of legislative enforcement, the water quality of the Tai Po WQO % Compliance Kau Stream has reached an “excellent” WQI 1988 2001 2002 in 2002 (Figure 2.5) and achieved 100% pH 100 100 100 Suspended solids 0 100 100 compliance with the key WQOs including the Dissolved oxygen 100 100 100 E.coli objective. Improving trends in many COD 86 100 100 parameters such as DO, aggregate organics BOD 29 75 83 5 and nutrients in the stream were also Overall 63 95 97 observed.

WQO compliance of Tai Po Kau Stream Reducing pollution in Lam Tsuen and Tai Po Rivers Tai Po Kau Stream WQO % Compliance 2.3.3 Since the late 80s, 78% of the 1987 2001 2002 organic pollutants have been removed from pH 91 100 100 Lam Tsuen and Tai Po Rivers (Table 2.2). To Suspended solids 0 100 100 further improve the river water quality, sewer Dissolved oxygen 18 100 100 COD 9 100 100 is planned to be constructed for 28 villages in BOD5 0 92 100 the Lam Tsuen Valley by 2010 under the Overall 24 98 100 North District and Tolo Harbour SMPs Review. Improving trend of DO in Tai Po Kau River (TR14) 2.3.4 Up to 2002, 19 villages in the Tai Po 10 area were provided with public sewer and 71% of the houses were connected to sewer. 9 In Kam Shan and Shui Wai, some 76 % of the 8 (mg/L) village houses have been connected to public sewer. Further sewerage works for 21 villages DO are scheduled to be built by 2004. 7

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

河 River Water Quality in Hong Kong in 2002 2 - 4 Chapter 2 Tolo Harbour and Channel Water Control Zone

Improving trend of COD in 2.5 Shan Liu and Tung Tze Streams Shan Liu Stream (TR4) 15 Shan Liu Stream

10 (mg/L)

COD 5

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

WQO compliance of Shan Liu Stream

Tung Tze Stream Shan Liu Stream WQO % Compliance 1987 2001 2002 pH 100 100 100 Suspended solids 100 100 100 Dissolved oxygen 100 100 100 COD 91 100 100 BOD5 100 100 83 Overall 98 100 97

Improving trend of BOD5 in Tung Tze Stream (TR6) 10

8 6 (mg/L)

2.5.1 In 2002, Shan Liu and Tung Tze 5 Streams have sustained an “excellent” and 4 BOD “good” WQI respectively (Figure 2.5). 2 Significant reductions in aggregated organics 0 and nutrients in the streams have resulted in a nearly full compliance with the key WQOs. 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year However, the E.coli levels remained fairly high (2,300 to 6,100 cfu/100mL) mainly due to pollution from unsewered villages in the WQO compliance of Tung Tze Stream catchment (Table 2.3B). Tung Tze Stream

WQO % Compliance

1987 2001 2002 pH 100 100 100 Suspended solids 0 100 100 Dissolved oxygen 64 100 100 COD 36 100 100 BOD5 55 100 100

Overall 51 100 100

河 River Water Quality in Hong Kong in 2002 2 - 5 Chapter 2 Tolo Harbour and Channel Water Control Zone

2.6 Tolo Harbour

Sewerage Master Plan

2.6.1 To further tackle pollution problem in the unsewered areas of the Tolo Harbour catchment, sewerage for some 100 villages/areas has been planned in the remaining parts of the Tolo Harbour Sewerage Master Plan (SMP) in the next few years.

2.6.2 By 2012, about 89,600 inhabitants will be provided with public sewer, resulting in the removal of 4,928 kg BOD/day of pollution load. This should further improve the river water quality in the Tolo Harbour catchment.

Tolo Harbour SMP works

Tolo Harbour Stage I Stage II SMP works

Tentative Implementation 1993– 2003a 2007 – 2012 Date (year) 1998–2009b

Estimated population 33,750a 12,750 provided with sewer (no.) 43,100b

Estimated pollution load 1,856a collected by sewer 701 2,371b (kg BOD /day) a – Phase I b – Phase II

河 River Water Quality in Hong Kong in 2002 2 - 6 Chapter 2 Tolo Harbour and Channel Water Control Zone Table 2.1A River water quality trends in the Tolo Harbour and Channel Water Control Zone based on the results of the Seasonal Kendall Test

Shing Mun River Watercourse Tin Sum Kwun Yam Siu Lek Yuen Tai Wai Nullah Nullah Shan Stream Nullah Monitoring station TR20B TR19A TR19C TR19 KY1 TR23L TR23A Monitoring period* 85-02 85-02 85-02 84-02 88-02 84-02 85-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L − pH − − − − Suspended solids mg/L −

BOD5 mg/L COD mg/L − Oil & grease mg/L − − − − − − E. coli cfu/100mL − − − − − Faecal coliforms cfu/100mL − − − − − − Ammonia-nitrogen mg/L − Nitrate-nitrogen mg/L − − − Total Kjeldahl mg/L nitrogen (SP) Ortho-phosphate mg/L − Total phosphorus mg/L (SP) Sulphide (SP) mg/L − − − − − − − Aluminium µg/L − − − − − Cadmium µg/L − − − − − − − Chromium µg/L − − − − − Copper µg/L − − − − Lead µg/L − − Zinc µg/L − − − − Flow L/s − − − − − ×

Notes: 1. (SP) Soluble and particulate fractions (i.e. total) of the water quality parameter. 2. − indicates no significant trend is detected at p < 0.05. 3. represents an increasing trend significant at p < 0.05. 4. represents a decreasing trend significant at p < 0.05. 5. × indicates no measurement was taken. 6. * indicates the monitoring period for most of the parameters, a few commenced in different years during the period.

河 River Water Quality in Hong Kong in 2002 2 - 7 Chapter 2 Tolo Harbour and Channel Water Control Zone Table 2.1B River water quality trends in the Tolo Harbour and Channel Water Control Zone based on the results of the Seasonal Kendall Test

Shing Mun River Tai Po Shan Tung Tai Po Watercourse Main Kau Liu Tze Fo Tan Nullah River Channel Stream Stream Stream Monitoring station TR17 TR17L TR19I TR13 TR14 TR4 TR6 Monitoring period* 82-02 81-02 85-02 81-02 81-02 81-02 81-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L − − − pH − − Suspended solids mg/L − −

BOD5 mg/L − − − COD mg/L − − Oil & grease mg/L − − − − − − − E. coli cfu/100mL − − − − − − Faecal coliforms cfu/100mL − − − − − − − Ammonia-nitrogen mg/L − − Nitrate-nitrogen mg/L − − − Total Kjeldahl mg/L nitrogen (SP) − Ortho-phosphate mg/L − Total phosphorus mg/L (SP) Sulphide (SP) mg/L − − − − − − Aluminium µg/L − − − − Cadmium µg/L − − − − − Chromium µg/L − − − − − Copper µg/L − − − − Lead µg/L − − − − Zinc µg/L − − − − − Flow L/s − × × − − ×

河 River Water Quality in Hong Kong in 2002 2 - 8 Chapter 2 Tolo Harbour and Channel Water Control Zone Table 2.1C River water quality trends in the Tolo Harbour and Channel Water Control Zone based on the results of the Seasonal Kendall Test

Watercourse Lam Tsuen River Monitoring station TR12H TR12D TR12G TR12F TR12C TR12B TR12E TR12 TR12I Monitoring period* 88-02 84-02 86-02 86-02 83-02 83-02 86-02 81-02 89-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L pH − − − Suspended solids mg/L − − −

BOD5 mg/L COD mg/L − Oil & grease mg/L − − − − − − − − − E. coli cfu/100mL − − − − − − − − Faecal coliforms cfu/100mL − − − − − − − − − Ammonia-nitrogen mg/L − − − Nitrate-nitrogen mg/L − − Total Kjeldahl mg/L nitrogen (SP) Ortho-phosphate mg/L − Total phosphorus mg/L (SP) Sulphide (SP) mg/L − − − − − − − − − Aluminium µg/L − − − − − − − − Cadmium µg/L − − − − − − − − − Chromium µg/L − − − − − − − − − Copper µg/L − − − − − − − − Lead µg/L − − − − − − Zinc µg/L − − − − − − − − Flow L/s − − − − − ×

河 River Water Quality in Hong Kong in 2002 2 - 9 Chapter 2 Tolo Harbour and Channel Water Control Zone Table 2.2 Pollution load reductions in the river catchments of the Tolo Harbour and Channel Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1987 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic N.A.(5) 3,600 529 3,071 85 Industrial 28 390 5 385 99 (1) Commercial 11 3,700 10 3,690 99 WPCO Institutional 32 N.A. N.A. N.A. N.A. Shing Mun Sub-total 71 7,690 544 7,146 93 River WDO(2) Livestock 0 610 0 610 100

Total 71 8,300 544 7, 756 93

Domestic N.A. 1,770 1,170 600 34 Industrial 16 1,200 1 1,199 99 Commercial 6 1,200 256 944 79 WPCO Institutional 16 N.A. N.A. N.A. N.A. Lam Tsuen River & Sub-total 38 4,170 1,427 2,743 66 Tai Po River WDO Livestock 0 2,246 0 2,246 100

Total 38 6,416 1,427 4,989 78

河 River Water Quality in Hong Kong in 2002 2 - 10 Cha 河 Table 2.3A Summary of water quality monitoring data for Shing Mun River in 2002 Sampling Station River WaterQualit p

Parameter Unit Tin Sum Nullah Tai Wai Nullah Kwun Yam Shan Stream Tolo Harbour and Channel Water Control Zone Siu Lek Yuen Nullah ter 2 TR20B TR19A TR19C TR19 KY1 TR23L TR23A Dissolved oxygen mg/L 8.4 8.6 9.0 9.4 8.5 9.1 7.4 (7.5 - 9.4) (7.6 - 10.5) (8.1 - 11.3) (8.1 - 13.6) (7.8 - 10.7) (7.9 - 11.2) (2.7 - 9.7) pH 7.8 8.5 7.7 7.6 8.0 8.7 7.9 (6.9 - 8.1) (7.7 - 10.0) (6.8 - 8.6) (6.8 - 8.7) (7.2 - 8.5) (8.1 - 9.2) (6.9 - 8.3) Suspended solids mg/L 3 7 6 10 3 2 5 (1 - 15) (3 - 150) (4 - 87) (5 - 63) (1 - 6) (1 - 11) (3 - 16) 5-day Biochemical Oxygen Demand mg/L 1124 1 34 y (1 - 5) (1 - 3) (1 - 3) (1 - 6) (1 - 2) (1 - 6) (2 - 14) inHon Chemical Oxygen Demand mg/L 6 8 7 10 3 7 13 (5 - 11) (4 - 10) (5 - 12) (4 - 16) (2 - 8) (2 - 16) (9 - 19) Oil & grease mg/L 0.5 0.5 0.5 0.5 0.5 0.5 0.5 g (0.5 - 0.7) (0.5 - 1.3) (0.5 - 0.7) (0.5 - 1.0) (0.5 - 0.5) (0.5 - 0.9) (0.5 - 0.8) Kon Faecal coliforms cfu/100mL 1 5,600 16,000 27,000 1,500 110,000 170,000 (1 - 8) (40 - 27,000) (730 - 240,000) (750 - 330,000) (250 - 8,600) (16,000 - 910,000) (20,000 - 920,000) g E. coli cfu/100mL 1 2,900 2,900 3,800 410 9,200 19,000 in 2002 (1 - 2) (40 - 19,000) (400 - 27,000) (240 - 24,000) (55 - 2,500) (530 - 130,000) (2,800 - 170,000) Ammonia-nitrogen mg/L 0.09 0.11 0.16 0.22 0.01 0.02 0.40 (0.01 - 0.18) (0.03 - 0.26) (0.04 - 0.35) (0.10 - 0.48) (0.01 - 0.03) (0.01 - 0.10) (0.13 - 0.75) Nitrate-nitrogen mg/L 2.55 1.70 1.30 1.60 0.56 0.21 0.56 (0.49 - 4.60) (1.10 - 3.70) (0.90 - 2.90) (0.96 - 3.80) (0.30 - 0.92) (0.12 - 0.50) (0.21 - 1.20) Total Kjeldahl nitrogen, SP mg/L 0.38 0.42 0.44 0.58 0.10 0.18 0.97 (0.20 - 0.89) (0.08 - 0.62) (0.11 - 0.89) (0.22 - 0.97) (0.05 - 0.38) (0.06 - 1.20) (0.36 - 1.50) Ortho-phosphate mg/L 0.02 0.02 0.05 0.08 0.10 0.03 0.05 (0.01 - 0.05) (0.01 - 0.03) (0.01 - 0.11) (0.03 - 0.25) (0.06 - 0.16) (0.01 - 0.10) (0.01 - 0.11) Total phosphorus, SP mg/L 0.06 0.04 0.09 0.14 0.13 0.04 0.12 (0.02- 0.39) (0.02 - 0.12) (0.04 - 0.28) (0.05 - 0.34) (0.08 - 0.18) (0.02 - 0.19) (0.03 - 0.22) Sulphide, SP mg/L 0.02 0.02 0.02 0.02 0.02 0.02 0.02 (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) Aluminium µg/L 620 305 180 270 50 85 130 (120 - 2,500) (80 - 1,000) (110 - 620) (90 - 830) (50 - 90) (50 - 590) (90 - 2,800) Cadmium µg/L 0.10 1.50 0.35 0.40 0.10 0.10 0.10 (0.10 - 0.30) (0.70 - 6.50) (0.20 - 1.60) (0.20 - 1.00) (0.10 - 0.20) (0.10 - 0.20) (0.10 - 3.70) Chromium µg/L 1.0 1.5 1.0 1.0 1.0 1.0 1.5 (1.0 - 3.0) (1.0 - 8.0) (1.0 - 6.0) (1.0 - 6.0) (1.0 - 1.0) (1.0 - 6.0) (1.0 - 15.0) Copper µg/L 3.5 3.0 40.0 40.5 2.0 3.0 5.0 (2.0 - 8.0) (2.0 - 4.0) (9.0 - 200.0) (10.0 - 160.0) (1.0 - 2.0) (1.0 - 40.0) (3.0 - 89.0) Lead µg/L 1.0 2.0 2.0 2.5 1.0 1.0 1.5 (1.0 - 1.0) (1.0 - 20.0) (1.0 - 14.0) (1.0 - 6.0) (1.0 - 2.0) (1.0 - 22.0) (1.0 - 38.0) Zinc µg/L 20 60 45 40 10 30 20 (10 - 40) (30 - 270) (20 - 130) (20 - 80) (10 - 30) (10 - 100) (10 - 1,900) Flow L/s 70 48 62 62 4 24 NM (7 - 167) (17 - 136) (29 - 180) (21 - 318) (1 - 49) (9 - 111)

2 -11 5. SP - soluble and particulate fractions i.e. total value. 6. Values at or below laboratory reporting limits are presented as laboratory reporting limits (see Table II). 7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. Cha 河 Table 2.3B Summary of water quality monitoring data for Shing Mun River, Tai Po River and minor streams in the Tolo Harbour & Channel Water Control Zone in 2002 Sampling Station River WaterQualit p

Parameter Unit Fo Tan Nullah Shing Mun Main Channel Tai Po River Tai Po Kau Stream Tolo Harbour and Channel Water Control Zone Shan Liu Stream Tung Tze Stream ter 2 TR17 TR17L TR19I TR13 TR14 TR4 TR6 Dissolved oxygen mg/L 8.3 6.7 6.6 8.1 8.8 7.3 5.7 (7.5 - 9.7) (4.6 - 12.2) (4.0 - 12.7) (6.4 - 9.1) (7.8 - 10.1) (5.7 - 8.3) (4.1 - 7.3) pH 8.0 7.6 7.9 7.1 7.4 7.4 7.4 (7.6 - 9.2) (7.0 - 8.2) (7.2 - 8.5) (6.7 - 7.3) (6.9 - 8.1) (7.1 - 8.3) (6.7 - 8.1) Suspended solids mg/L 15 5 5 3459 (4 - 85) (2 - 20) (3 - 12) (1 - 7) (2 - 27) (2 - 230) (1 - 26) 5-day Biochemical Oxygen Demand mg/L 10 3 4 2112 y (1 - 72) (1 - 15) (1 - 14) (1 - 8) (1 - 2) (1 - 6) (1 - 3) inHon Chemical Oxygen Demand mg/L 21 10 17 7 3 5 14 (3 - 54) (6 - 27) (7 - 22) (2 - 14) (2 - 12) (2 - 13) (8 - 21) Oil & grease mg/L 0.8 0.5 0.5 0.5 0.5 0.5 0.5 g (0.5 - 5.1) (0.5 - 0.8) (0.5 - 0.7) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) Kon Faecal coliforms cfu/100mL 340,000 39,000 13,000 80,000 1,100 19,000 6,000 (79,000 - 2,400,000) (4,600 - 440,000) (2,500 - 260,000) (19,000 - 430,000) (130 - 3,400) (8,700 - 39,000) (640 - 30,000) g E. coli cfu/100mL 44,000 3,700 1,900 33,000 200 6,100 2,300 in 2002 (11,000 - 370,000) (400 - 42,000) (530 - 24,000) (10,000 - 110,000) (36 - 540) (2,000 - 23,000) (360 - 12,000) Ammonia-nitrogen mg/L 0.09 0.21 0.21 0.41 0.02 0.27 0.46 (0.01 - 1.40) (0.14 - 0.45) (0.04 - 0.36) (0.07 - 3.80) (0.01 - 0.10) (0.09 - 0.61) (0.17 - 0.81) Nitrate-nitrogen mg/L 0.76 0.44 0.59 0.67 0.16 0.51 0.21 (0.01 - 1.60) (0.10 - 1.10) (0.12 - 1.20) (0.36 - 1.20) (0.09 - 0.32) (0.18 - 1.80) (0.04 - 1.50) Total Kjeldahl nitrogen, SP mg/L 1.04 0.54 0.64 0.87 0.11 0.38 0.75 (0.21 - 5.90) (0.42 - 1.40) (0.44 - 1.30) (0.23 - 4.50) (0.06 - 0.30) (0.11 - 1.00) (0.30 - 1.30) Ortho-phosphate mg/L 0.05 0.03 0.01 0.12 0.02 0.08 0.05 (0.01 - 0.32) (0.01 - 0.04) (0.01 - 0.04) (0.04 - 0.69) (0.01 - 0.04) (0.03 - 0.16) (0.01 - 0.23) Total phosphorus, SP mg/L 0.17 0.06 0.06 0.20 0.03 0.10 0.10 (0.03 - 1.10) (0.04 - 0.12) (0.04 - 0.15) (0.05 - 0.78) (0.02 - 0.08) (0.04 - 0.35) (0.04 - 0.39) Sulphide, SP mg/L 0.02 0.02 0.02 0.02 0.02 0.02 0.02 (0.02 - 0.22) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) Aluminium µg/L 180 105 105 50 70 65 120 (70 - 1,000) (50 - 230) (50 - 230) (50 - 80) (50 - 160) (50 - 380) (60 - 200) Cadmium µg/L 0.15 0.10 0.10 0.10 0.10 0.10 0.10 (0.10 - 0.40) (0.10 - 0.10) (0.10 - 0.10) (0.10 - 1.40) (0.10 - 0.70) (0.10 - 0.10) (0.10 - 0.20) Chromium µg/L 1.0 4.0 4.0 1.0 1.0 1.0 2.5 (1.0 - 7.0) (1.0 - 8.0) (1.0 - 7.0) (1.0 - 1.0) (1.0 - 2.0) (1.0 - 4.0) (1.0 - 7.0) Copper µg/L 6.5 6.5 7.0 2.5 2.0 2.5 5.5 (2.0 - 14.0) (4.0 - 14.0) (3.0 - 14.0) (2.0 - 4.0) (1.0 - 4.0) (1.0 - 9.0) (3.0 - 10.0) Lead µg/L 3.5 1.0 1.0 1.0 2.0 1.0 2.0 (1.0 - 27.0) (1.0 - 5.0) (1.0 - 3.0) (1.0 - 2.0) (1.0 - 6.0) (1.0 - 15.0) (1.0 - 4.0) Zinc µg/L 45 30 20 20 15 10 20 (10 - 120) (10 - 120) (10 - 30) (10 - 30) (10 - 30) (10 - 60) (20 - 20) Flow L/s 87 NM NM 151 26 53 NM (29 - 432) (63 - 849) (5 - 50) (18 - 224)

2 -12 5. SP - soluble and particulate fractions i.e. total value. 6. Values at or below laboratory reporting limits are presented as laboratory reporting limits (see Table II). 7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. Chapter 2 Tolo Harbour and Channel Water Control Zon Tolo Control HarbourandChannelWater 2 Chapter 河 Table 2.3C Summary of water quality monitoring data for Lam Tsuen River in 2002 Sampling Station River Water Quality in Hong Kong in 2002 Parameter Unit Lam Tsuen River TR12H TR12D TR12G TR12F TR12C TR12B TR12E TR12 TR12I Dissolved oxygen mg/L 8.6 8.7 8.2 8.3 8.1 9.1 8.2 9.3 5.8 (8.1 - 10.4) (7.7 - 10.3) (7.0 - 10.1) (7.2 - 10.2) (7.7 - 10.2) (8.2 - 10.8) (7.5 - 9.6) (8.4 - 12.8) (4.0 - 16.0) pH 7.4 7.5 7.4 7.5 7.6 7.4 7.9 7.5 7.4 (7.0 - 7.6) (7.2 - 8.8) (6.9 - 7.6) (7.0 - 7.8) (7.3 - 7.8) (7.1 - 7.8) (7.5 - 8.4) (7.1 - 9.2) (7.1 - 8.5) Suspended solids mg/L 1 1 2 1 27 2 24 6 5 (1 - 5) (1 - 1,200) (1 - 7) (1 - 2) (9 - 570) (1 - 11) (5 - 200) (4 - 14) (3 - 9) 5-day Biochemical Oxygen Demand mg/L 1 1 1 1 3 1 1 2 4 (1 - 2) (1 - 1) (1 - 2) (1 - 1) (1 - 8) (1 - 6) (1 - 3) (1 - 5) (1 - 10) Chemical Oxygen Demand mg/L 2 2 4 5 16 4 5 9 14 (2 - 5) (2 - 9) (2 - 7) (2 - 8) (9 - 150) (2 - 25) (2 - 9) (2 - 27) (3 - 22) Oil & grease mg/L 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) Faecal coliforms cfu/100mL 2,400 1,600 2,000 7,600 6,500 7,500 7,700 6,800 92,000 (170 - 8,500) (35 - 19,000) (470 - 6,500) (900 - 29,000) (2 - 1,100,000) (1,000 - 40,000) (2,800 - 31,000) (21 - 38,000) (1,100 - 420,000) E. coli cfu/100mL 400 100 170 2,200 940 1,700 2,200 640 14,000 (47 - 5,100) (14 - 370) (20 - 870) (320 - 14,000) (1 - 52,000) (130 - 31,000) (670 - 23,000) (3 - 4,300) (49 - 130,000) Ammonia-nitrogen mg/L 0.01 0.02 0.01 0.08 0.20 0.05 0.04 0.18 0.50 (0.01 - 0.03) (0.01 - 0.05) (0.01 - 0.02) (0.02 - 0.18) (0.05 - 0.83) (0.02 - 0.10) (0.01 - 0.15) (0.03 - 0.40) (0.04 - 0.82) Nitrate-nitrogen mg/L 0.65 0.37 0.04 0.48 2.55 0.96 0.85 3.40 0.70 (0.38 - 0.90) (0.10 - 0.65) (0.02 - 0.05) (0.31 - 0.67) (1.20 - 5.60) (0.54 - 5.50) (0.21 - 3.60) (0.82 - 9.10) (0.20 - 1.70) Total Kjeldahl nitrogen, SP mg/L 0.11 0.09 0.11 0.18 1.30 0.21 0.17 0.47 0.90 (0.05 - 1.40) (0.05 - 1.20) (0.05 - 0.27) (0.07 - 0.28) (0.30 - 11.00) (0.08 - 1.80) (0.11 - 0.33) (0.14 - 1.80) (0.42 - 1.80) Ortho-phosphate mg/L 0.03 0.01 0.02 0.05 0.03 0.08 0.03 0.27 0.11 (0.01 - 0.04) (0.01 - 0.09) (0.01 - 0.04) (0.03 - 0.09) (0.02 - 0.20) (0.03 - 0.80) (0.02 - 0.05) (0.05 - 1.60) (0.01 - 0.21) Total phosphorus, SP mg/L 0.04 0.02 0.06 0.08 0.87 0.11 0.05 0.45 0.19 (0.03 - 0.06) (0.02 - 0.99) (0.03 - 0.13) (0.05 - 0.12) (0.28 - 23.00) (0.04 - 1.10) (0.02 - 0.16) (0.06 - 2.00) (0.11 - 0.31) Sulphide, SP mg/L 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) Aluminium µg/L 50 50 50 50 3,000 50 280 265 95 (50 - 50) (50 - 2,400) (50 - 50) (50 - 100) (700 - 85,700) (50 - 270) (130 - 710) (50 - 720) (50 - 250) Cadmium µg/L 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 (0.10 - 0.10) (0.10 - 2.60) (0.10 - 0.10) (0.10 - 0.10) (0.10 - 1.40) (0.10 - 0.10) (0.10 - 0.10) (0.10 - 0.10) (0.10 - 0.10) Chromium µg/L 1.0 1.0 1.0 1.0 3.0 1.0 1.0 1.0 3.0 (1.0 - 1.0) (1.0 - 2.0) (1.0 - 1.0) (1.0 - 1.0) (1.0 - 93.0) (1.0 - 1.0) (1.0 - 2.0) (1.0 - 1.0) (1.0 - 5.0) Copper µg/L 1.0 1.5 1.0 1.0 11.0 2.0 1.5 4.5 5.0 (1.0 - 7.0) (1.0 - 30.0) (1.0 - 2.0) (1.0 - 2.0) (3.0 - 220.0) (1.0 - 6.0) (1.0 - 4.0) (2.0 - 9.0) (2.0 - 12.0) Lead µg/L 1.0 1.0 1.0 1.0 3.0 1.0 2.5 2.0 1.0 (1.0 - 3.0) (1.0 - 200.0) (1.0 - 1.0) (1.0 - 2.0) (1.0 - 8.0) (1.0 - 2.0) (1.0 - 15.0) (1.0 - 2.0) (1.0 - 2.0) Zinc µg/L 10 25 10 10 30 20 25 20 20 (10 - 50) (10 - 360) (10 - 30) (10 - 40) (20 - 630) (10 - 30) (10 - 50) (10 - 70) (10 - 140) Flow L/s 38 35 32 29 102 139 74 159 NM (12 - 166) (2 - 432) (3 - 171) (2 - 98) (17 - 1,080) (26 - 1,658) (15 - 360) (22 - 2,412)

2 -13 5. SP - soluble and particulate fractions i.e. total value. 6. Values at or below laboratory reporting limits are presented as laboratory reporting limits (see Table II).

7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. e Chapter 2 河 TR19A River Water QualityWater inHongRiver Kongin2002 3 Excellent 6 Good N Tolo Harbour 9 Fair

12 Bad

Water QualityWater Index Very Bad 15 Fo Tan Nullah 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Racecourse

HK Sports Shing Mun River Institute TR19C Sha Tin 3 Main Channel Excellent Wo Che Estate

6 Good Lek Yuen Estate City One Kuk Liu Sha Tin

9 Fair Heung Fan Liu Kwong Yuen Estate Siu Lek Yuen and Channel WaterControlZone Harbour Tolo Tai Wai Hang Seng 12 Bad Nullah School of Commerce Nullah Water QualityWater Index Very Bad Tin Sum 15

1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Hin Keng Estate Year Tin Sum Nullah

TR19 TR20B TR19I 3 3 3 Excellent Excellent Excellent

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

River Water QualityWater inHongRiver Kongin2002 TR23A 3 N Tolo Harbour Excellent TR17 6 Good 3 Excellent

9 Fair 6 Good

12 Bad 9 Fair

Water QualityWater Index Very Bad 15 12 Bad Fo Tan Nullah 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Water QualityWater Index Very Bad 15 Year Racecourse 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Fo Tan Station Shing Mun River HK Sports TR23L Institute 3 Main Channel Excellent Sha Tin Wo Che Estate 6 Good Lek Yuen Estate City One Sha Tin 9 Fair

Kuk Liu and Channel WaterControlZone Harbour Tolo Heung Fan Liu Kwong Yuen 12 Bad Tai Wai Estate

Hang Seng QualityWater Index Tai Wai Station Very Bad Nullah School of Commerce Siu Lek 15 Yuen Nullah 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Tin Sum Nullah Year

Hin Keng Estate

TR17L KY1 3 Kwun Yam Shan 3 Excellent Nullah Excellent 6 Good 6 Good

9 Fair 9 Fair

12 Bad 12 Bad Water QualityWater Index Very Bad QualityWater Index Very Bad 15 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year 15 2 - Figure 2.2 Water Quality Index (WQI) of Shing Mun River and its tributaries (continued) Chapter 2 河

River Water QualityWater inHongRiver Kongin2002 TR12C TR12B 3 3 Excellent N Excellent 6 Good 6 Good

9 Fair 9 Fair

12 Bad Lam Tsuen River 12 Bad

TR12F Lam Tsuen Kuk She Tai Wo Tai Po 3 Excellent Shan Tin Tai Po Hui 6 Good Liu Kam Shan Tolo Lam Tsuen Ha To Yuen Shan Tong Harbour 9 Fair Tung ooHrorand Channel WaterControlZone Harbour Tolo

12 Bad Ping Long

Water QualityWater Index Very Bad Tai Mong Che 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Pak Ngau Shek

TR12G TR12H TR12D 3 3 3 Excellent Excellent Excellent

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

12 Bad 12 Bad 12 Bad Water Quality Index Quality Water Water QualityWater Index Water QualityWater Index Very Bad Very Bad Very Bad 15 15 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year Year 16 2 - Figure 2.3 Water Quality Index (WQI) of Lam Tsuen River and its tributaries Chapter 2 河

River Water QualityWater inHongRiver Kongin2002 TR12I 3 Lam Tsuen River Excellent N Kau Liu Ha Tai Po 6 Good 9 Fair Shui Wai She 12 Bad Lam Tsuen Kuk Shan Tai Wo

Water QualityWater Index Very Bad 15 Tin Liu Kam Shan Tai Po Hui

Lam Tsuen 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Ha To Yuen Year Tung Shan Tong

Ping Long Tolo Harbour Tai Mong Che Tai Po River

Pak Ngau Shek and Channel WaterControlZone Harbour Tolo

TR12E TR12 TR13 3 3 3 Excellent Excellent Excellent

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

12 Bad 12 Bad 12 Bad Water QualityWater Index Water QualityWater Index Very Bad QualityWater Index Very Bad Very Bad 15 15 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year Year 17 2 - Figure 2.4 Water Quality Index (WQI) of Lam Tsuen River (continued) and Tai Po River and their tributaries Chapter 2 河 River Water QualityWater inHongRiver Kongin2002

TR6 TR4 3 3 Excellent Excellent

6 Good N 6 Good

9 Fair 9 Fair

12 Bad 12 Bad Water QualityWater Index Water QualityWater Index Very Bad Very Bad 15 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year

TR14

3 and Channel WaterControlZone Harbour Tolo Excellent

6 Good Shan Liu Stream 9 Fair Plover Cove Ting Kok Reservoir 12 Bad Ha Tei Ha Water QualityWater Index Very Bad 15 Tung Tze Stream Plover

1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Cove Year Tai Po Tolo Harbour Lai Chi Hang Cheung Shue Tan Ma Liu Shui Tai Po Kau Stream 18 2 - Figure 2.5 Water Quality Index (WQI) of minor streams in the Tolo Harbour and Channel Water Control Zone Chapter 3 Southern Water Control Zone

WQO compliance of Mui Wo River 3. Southern Water Control Zone Mui Wo River WQO % Compliance

1988 2001 2002 pH 47 98 100 3.1 Mui Wo River Suspended solids 80 100 100 Dissolved oxygen 77 100 100 COD 36 100 100 BOD5 51 100 97 Overall 58 99 99

3.1.3 Due to the effect of sullage and occasional overflow from septic tanks as well as surface runoff from nearby villages, the E.coli levels in Mui Wo River remained high (Table 3.3) and the downstream Silvermine Bay Beach only achieved a “fair” grading in 2002.

E. coli level in

3.1.1 The 15 km long Mui Wo River Mui Wo River (MW1) 10,000 covers a catchment area of 3.5 km2 and flows onto Silvermine Bay Beach in the eastern shore of Lantau Island.

(cfu/100mL)

3.1.2 Since the early 90s, the Mui Wo

E. coli River has sustained a “good” to “excellent” 1,000 Water Quality Index with marked reduction in

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 organic pollutants in the river. In 2002, it has Year also achieved a nearly full compliance with the five key Water Quality Objectives. 3.1.4 To further improve the

bacteriological quality of Mui Wo River and

Silvermine Bay Beach, the Mui Wo Sewage Improving trend of BOD5 in Treatment Works is planned to be upgraded Mui Wo River (MW1) 6 and the sewer network is planned to be

expanded to serve unsewered villages in the

river catchment between 2006 and 2010. By 4 then, some 150 kg BOD/day of the pollution (mg/L)

5 load from 2,500 inhabitants will be diverted to 2 BOD the public sewerage for proper treatment and

disposal.

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

河 River Water Quality in Hong Kong in 2002 3 - 1 Chapter 3 Southern Water Control Zone Table 3.1 River water quality trends in the Southern Water Control Zone based on the results of the Seasonal Kendall Test

Watercourse Mui Wo River Monitoring station MW1 MW2 MW3 MW4 MW5 Monitoring period* 84-02 84-02 84-02 88-02 88-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L pH − Suspended solids mg/L − −

BOD5 mg/L COD mg/L Oil & grease mg/L − − − − − E. coli cfu/100mL − − − Faecal coliforms cfu/100mL − − Ammonia-nitrogen mg/L − − Nitrate-nitrogen mg/L − Total Kjeldahl mg/L nitrogen (SP) − Ortho-phosphate mg/L − Total phosphorus mg/L (SP) − Sulphide (SP) mg/L − − − − − Aluminium µg/L − − Cadmium µg/L − − − − − Chromium µg/L − − − − − Copper µg/L − − − Lead µg/L − − − − Zinc µg/L − − − − − Flow L/s × − −

河 River Water Quality in Hong Kong in 2002 3 - 2 Chapter 3 Southern Water Control Zone Table 3.2 Pollution load reduction in the Mui Wo River catchment of the Southern Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1988 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic 0 8 0 8 100 Industrial 0 0 0 N.A.(5) N.A. (1) Commercial 0 5 0 5 100 WPCO Institutional 0 2 0 2 100

Mui Wo Sub-total 0 15 0 15 100 River WDO(2) Livestock 0 178 0 178 100

Total 0 193 0 193 100

河 River Water Quality in Hong Kong in 2002 3 - 3 Chapter 3 Southern Water Control Zon Control Water Southern 3 Chapter 河 Table 3.3 Summary of water quality monitoring data for Mui Wo River in 2002 Sampling Station River Water Quality in Hong Kong in 2002 Parameter Unit Mui Wo River MW1 MW2 MW3 MW4 MW5 Dissolved oxygen mg/L 8.5 9.2 9.1 8.2 8.3 (7.6 - 11.4) (6.8 - 10.9) (7.4 - 13.2) (6.0 - 10.6) (5.9 - 10.8) pH 7.1 7.6 7.3 7.2 7.3 (6.7 - 7.9) (7.2 - 8.0) (6.9 - 7.7) (6.7 - 8.0) (6.9 - 8.2) Suspended solids mg/L 2 5 2 9 8 (1 - 4) (4 - 13) (1 - 8) (3 - 15) (3 - 23) 5-day Biochemical Oxygen Demand mg/L 1 3 1 1 2 (1 - 3) (1 - 5) (1 - 2) (1 - 3) (1 - 8) Chemical Oxygen Demand mg/L 3 11 2 10 10 (2 - 12) (2 - 15) (2 - 5) (2 - 14) (2 - 21) Oil & grease mg/L 0.5 0.5 0.5 0.5 0.5 (0.5 - 0.6) (0.5 - 0.6) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) Faecal coliforms cfu/100mL 6,300 24,000 1,500 3,700 20,000 (500 - 39,000) (2,300 - 440,000) (400 - 21,000) (490 - 16,000) (4,500 - 210,000) E. coli cfu/100mL 1,600 4,800 64 980 3,000 (180 - 22,000) (520 - 87,000) (6 - 530) (160 - 6,300) (440 - 63,000) Ammonia-nitrogen mg/L 0.04 0.48 0.01 0.15 0.52 (0.01 - 0.54) (0.03 - 1.80) (0.01 - 0.04) (0.08 - 0.26) (0.06 - 2.30) Nitrate-nitrogen mg/L 0.23 0.14 0.22 0.15 0.13 (0.14 - 0.43) (0.07 - 0.25) (0.09 - 0.48) (0.06 - 0.43) (0.08 - 1.20) Total Kjeldahl nitrogen, SP mg/L 0.15 0.71 0.09 0.32 0.89 (0.07 - 0.79) (0.15 - 2.20) (0.06 - 0.28) (0.18 - 0.49) (0.16 - 2.80) Ortho-phosphate mg/L 0.11 0.11 0.04 0.04 0.06 (0.03 - 0.25) (0.04 - 0.26) (0.02 - 0.08) (0.02 - 0.16) (0.02 - 0.15) Total phosphorus, SP mg/L 0.15 0.18 0.07 0.09 0.15 (0.04 - 0.27) (0.07 - 0.39) (0.03 - 0.15) (0.07 - 0.24) (0.06 - 0.68) Sulphide, SP mg/L 0.02 0.02 0.02 0.02 0.02 (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) Aluminium µg/L 60 85 50 120 110 (50 - 120) (50 - 130) (50 - 120) (50 - 190) (50 - 180) Cadmium µg/L 0.10 0.10 0.10 0.10 0.10 (0.10 - 0.10) (0.10 - 0.30) (0.10 - 0.10) (0.10 - 0.10) (0.10 - 0.10) Chromium µg/L 1.0 1.0 1.0 3.5 1.5 (1.0 - 3.0) (1.0 - 5.0) (1.0 - 1.0) (1.0 - 6.0) (1.0 - 6.0) Copper µg/L 2.0 3.0 2.0 5.5 2.0 (1.0 - 5.0) (1.0 - 7.0) (1.0 - 3.0) (1.0 - 7.0) (1.0 - 6.0) Lead µg/L 1.0 1.5 1.0 2.0 2.0 (1.0 - 4.0) (1.0 - 3.0) (1.0 - 2.0) (1.0 - 3.0) (1.0 - 4.0) Zinc µg/L 20 20 25 20 20 (10 - 30) (10 - 40) (10 - 50) (10 - 30) (10 - 30) Flow L/s 31 NM 7 216 31 (3 - 621) (2 - 850) (40 - 1,014) (11 - 228)

7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. e Chapter 3 河

ie ae ult nHn ogi 023-5 - 3 QualityWater inHongRiver Kongin2002 MW5 3 Excellent N 6 Good

9 Fair

12 Bad

Water QualityWater Index Very Bad 15 Wang Tong 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Pak Ngan Butterfly Year Heung Hill

Tai Tei Tong Silver Mine MW2 Chung Mui Wo 3 Hau Excellent School San Bay Lung 6 Good Wai Ngan Wan Estate 9 Fair

Luk Tei 12 Tong Bad

Water QualityWater Index Very Bad Mui Wo River 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

MW3 MW1 MW4 3 3 3 ZoneSouthern Control Water Excellent Excellent Excellent

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

Figure 3.1 Water Quality Index (WQI) of Mui Wo River and its tributaries Chapter 4 Port Shelter Water Control Zone

WQO compliance of Ho Chung River 4. Port Shelter Water Control Zone Ho Chung River WQO % Compliance

1989 2001 2002 pH 65 100 100 4.1 Ho Chung River Suspended solids 50 100 100 Dissolved oxygen 45 100 100 COD 50 100 100 BOD5 50 100 100 Overall 52 100 100

4.1.3 Due to the unsewered villages in the catchment, the bacterial E.coli levels in the river were still substantial (Table 4.3). To further improve the river quality, public sewer network was planned to extend to the unsewered areas under the Port Shelter Sewerage Master Plan (SMP), which is planned to be completed around 2010.

4.1.1 The 20 km long Ho Chung River runs through the Ho Chung Valley in Sai 4.2 Sha Kok Mei Stream

Kung and flows into Hebe Haven. The river has a catchment area of 7.2 km2.

4.1.2 After 13 years’ legislative enforcement, there has been a significant reduction of organic pollution in the Ho Chung River (Tables 4.1 and 4.2). The river has achieved full compliance (100%) with the key Water Quality Objectives (WQOs) and an “excellent” Water Quality Index (WQI) in both 2001 and 2002 (Figure 4.1).

Improving trend of BOD in 5 Ho Chung River (PR1) 50 4.2.1 The Sha Kok Mei Stream is around 10 km in length and runs through Fu Tei Hau, 40 Sha Kok Mei and Sai Kung Town before 30 entering Sai Kung Hoi. (mg/L)

5 20 4.2.2 Since the implementation of Water

BOD 10 Pollution Control Ordinance in 1989, there has been a substantial improvement in the 0 water quality of Sha Kok Mei Stream 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 particularly at its downstream station (Table Year 4.1). Similar to 2001, the stream has achieved full WQO compliance with four of

河 River Water Quality in Hong Kong in 2002 4 - 1 Chapter 4 Port Shelter Water Control Zone the key parameters in 2002. In addition, the WQI was upgraded from “good” in 2001 to 4.3 Tai Chung Hau Stream “excellent” in 2002 (Figure 4.2).

WQO compliance of Sha Kok Mei Stream

Sha Kok Mei Stream

WQO % Compliance 1989 2001 2002 pH 100 100 100 Suspended solids 100 100 100 Dissolved oxygen 80 100 100 COD 80 100 100 BOD5 50 83 88 Overall 82 97 98

4.2.3 Despite the improvement, the E.coli 4.3.1 The Tai Chung Hau Stream finds its level in the Sha Kok Mei Stream was still origin in the Ma On Shan Country Park and fairly high ranging between 1,400 cfu/100mL flows into the inner part of Hebe Haven. and 12,000 cfu/100mL due to pollution from unsewered villages in the catchment (Table 4.3.2 Since the late 80s, significant 4.3). With the progressive provision of improvements in many water quality sewerage facilities, the remaining 226 kg parameters have prevailed in the Tai Chung BOD/day of the pollution load in the Sha Kok Hau Stream (Table 4.1). The stream has also Mei Stream would be further reduced (Table sustained its “excellent” WQI and full WQO 4.2). compliance with the five key parameters in the past four years (Figure 4.3).

Improving trend of BOD in 5 Improving trend of BOD in Sha Kok M e i Str e am (PR5) 5 25 Tai Chung Hau Stream (PR7) 200

20 150 15 (mg/L)

(mg/L)

5 100

5 10 BOD BOD 5 50

0 0

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year

WQO compliance of Tai Chung Hau Stream

Tai Chung Hau Stream

WQO % Compliance 1989 2001 2002 pH 80 100 100 Suspended solids 0 100 100 Dissolved oxygen 70 100 100 COD 30 100 100 BOD 0 100 100 5 Overall 36 100 100

河 River Water Quality in Hong Kong in 2002 4 - 2 Chapter 4 Port Shelter Water Control Zone

4.3.3 Despite the improvement, some 220 kg BOD/day of organic pollutant still remained in the Tai Chung Hau Stream (Table 4.2). This was likely to be attributed to the unsewered villages in the catchment, which may also be the main reason for the fairly high E. coli content in the stream (Table 4.3). The faecal contamination should be reduced with the progressive provision of rural sewerage under the Port Shelter SMP which is planned to be completed around 2010.

4.4 Port Shelter

Sewerage Master Plan

4.4.1 The Port Shelter SMP Study recommended that public sewer in the Port Shelter catchment would be constructed in 3 stages to serve 62,400 population. The overall completion date for the works has been deferred from 2007 to 2010. Under Stage II of the SMP, sewer network in the Sha Kok Mei and Tai Chung Hau areas is planned to be completed by 2005 and 2009 respectively. Stage III of the SMP (including the sewer project in Ho Chung) is planned to be completed by year 2010.

Port Shelter SMP works

Port Shelter Stage I Stage II Stage III SMP works

Tentative Implementation 1993–2001 1995–2010 2005–2010 Date (year)

Estimated population 11,500 23,600 27,300 provided with sewer (no.)

Estimated pollution load collected by 630 1,300 1,500 sewer per day (kg BOD /day)

河 River Water Quality in Hong Kong in 2002 4 - 3 Chapter 4 Port Shelter Water Control Zone Table 4.1 River water quality trends in the Port Shelter Water Control Zone based on the results of the Seasonal Kendall Test

Watercourse Ho Chung River Sha Kok Mei Stream Tai Chung Hau Stream Monitoring station PR1 PR2 PR5 PR6 PR7 PR8 Monitoring period* 83-02 83-02 89-02 89-02 89-02 89-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L pH − Suspended solids mg/L −

BOD5 mg/L − COD mg/L − Oil & grease mg/L − − − − − E. coli cfu/100mL − − − − − Faecal coliforms cfu/100mL − − − − Ammonia-nitrogen mg/L − Nitrate-nitrogen mg/L − − Total Kjeldahl mg/L nitrogen (SP) − Ortho-phosphate mg/L Total phosphorus mg/L (SP) − Sulphide (SP) mg/L − − − − − − Aluminium µg/L − Cadmium µg/L − − − − − − Chromium µg/L − − − − − Copper µg/L − − − Lead µg/L − − − − Zinc µg/L − − − − Flow L/s × × − ×

河 River Water Quality in Hong Kong in 2002 4 - 4 Chapter 4 Port Shelter Water Control Zone Table 4.2 Pollution load reductions in the river catchments of the Port Shelter Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1989 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic 1,450 185 101 84 45 Industrial 4 67 1 66 99 (1) Commercial 0 40 0 40 100 WPCO Institutional 1 2 0 2 100

Ho Chung Sub-total 1,455 294 102 192 65 River WDO(2) Livestock 0 88 0 88 100

Total 1,455 382 102 280 73 Domestic 2,406 398 226 172 43 Industrial 0 2 0 2 100 Commercial 0 N.A(5). N.A. N.A. N.A. WPCO Institutional 0 N.A. N.A. N.A. N.A.

Sha Kok Mei Sub-total 2,406 400 226 174 44 Stream WDO Livestock 0 16 0 16 100

Total 2,406 416 226 190 46 Domestic 3,788 324 222 102 31 Industrial 0 5 0 5 100 Commercial 0 N.A. N.A. N.A. N.A. WPCO Institutional 0 N.A. N.A. N.A. N.A.

Tai Chung Sub-total 3,788 329 222 107 33 Hau Stream WDO Livestock 0 54 0 54 100

Total 3,788 383 222 161 42

河 River Water Quality in Hong Kong in 2002 4 - 5 Cha 河 Table 4.3 Summary of water quality monitoring data for Ho Chung River, Sha Kok Mei Stream and Tai Chung Hau Stream in 2002 Sampling Station River WaterQualit p

Parameter Unit Ho Chung River Sha Kok Mei Stream ShelterWaterControlZone Port Tai Chung Hau Stream ter 4 PR1 PR2 PR5 PR6 PR7 PR8 Dissolved oxygen mg/L 7.6 8.7 8.2 8.3 8.6 8.1 (6.2 - 9.2) (7.8 - 10.1) (6.7 - 9.5) (7.7 - 10.1) (7.6 - 10.4) (7.2 - 9.8) pH 7.3 7.6 7.4 7.4 7.6 7.5 (6.8 - 7.9) (7.0 - 7.9) (7.0 - 7.6) (7.0 - 7.8) (7.0 - 8.9) (7.0 - 8.1) Suspended solids mg/L 5 2 2 4 4 3 (3 - 11) (1 - 15) (1 - 6) (3 - 6) (3 - 19) (1 - 75) 5-day Biochemical Oxygen Demand mg/L 1 1 1 2 1 1 y (1 - 2) (1 - 2) (1 - 3) (1 - 8) (1 - 4) (1 - 2) inHon Chemical Oxygen Demand mg/L 7 3 5 8 5 5 (2 - 15) (2 - 15) (2 - 12) (2 - 16) (2 - 12) (2 - 12) Oil & grease mg/L 0.5 0.5 0.5 0.5 0.5 0.5 g (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 1.0) (0.5 - 0.5) (0.5 - 0.5) Kon Faecal coliforms cfu/100mL 12,000 3,800 3,800 56,000 13,000 4,700 (900 - 110,000) (1,100 - 21,000) (10 - 36,000) (21,000 - 160,000) (3,000 - 58,000) (10 - 60,000) g E. coli cfu/100mL 2,500 1,300 1,400 12,000 5,600 2,500 in 2002 (330 - 16,000) (180 - 9,000) (10 - 8,500) (3,900 - 28,000) (1,900 - 36,000) (10 - 35,000) Ammonia-nitrogen mg/L 0.26 0.02 0.17 0.44 0.07 0.06 (0.06 - 0.75) (0.01 - 0.05) (0.06 - 0.44) (0.13 - 1.50) (0.02 - 0.14) (0.02 - 0.14) Nitrate-nitrogen mg/L 0.30 0.29 0.95 1.85 0.91 1.45 (0.05 - 0.42) (0.12 - 0.74) (0.46 - 1.50) (0.99 - 2.60) (0.34 - 2.10) (0.72 - 2.20) Total Kjeldahl nitrogen, SP mg/L 0.51 0.11 0.33 0.64 0.22 0.17 (0.20 - 0.85) (0.05 - 0.50) (0.12 - 0.73) (0.24 - 2.40) (0.07 - 0.50) (0.09 - 0.59) Ortho-phosphate mg/L 0.04 0.02 0.06 0.14 0.06 0.07 (0.01 - 0.08) (0.01 - 0.06) (0.02 - 0.10) (0.07 - 0.22) (0.04 - 0.09) (0.02 - 0.10) Total phosphorus, SP mg/L 0.09 0.03 0.11 0.18 0.09 0.10 (0.05 - 0.14) (0.02 - 0.14) (0.07 - 0.14) (0.12 - 0.43) (0.06 - 0.10) (0.08 - 0.17) Sulphide, SP mg/L 0.02 0.02 0.02 0.02 0.02 0.02 (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) Aluminium µg/L 85 50 60 80 90 80 (50 - 200) (50 - 180) (50 - 110) (50 - 140) (50 - 220) (50 - 290) Cadmium µg/L 0.10 0.10 0.10 0.10 0.10 0.10 (0.10 - 0.20) (0.10 - 0.10) (0.10 - 0.20) (0.10 - 0.10) (0.10 - 0.20) (0.10 - 0.30) Chromium µg/L 3.0 1.0 1.0 1.0 1.0 1.0 (1.0 - 8.0) (1.0 - 1.0) (1.0 - 4.0) (1.0 - 1.0) (1.0 - 2.0) (1.0 - 3.0) Copper µg/L 4.0 1.0 2.0 3.0 2.5 3.0 (2.0 - 7.0) (1.0 - 3.0) (1.0 - 4.0) (1.0 - 4.0) (1.0 - 4.0) (2.0 - 5.0) Lead µg/L 1.0 1.0 1.0 1.0 1.0 1.0 (1.0 - 4.0) (1.0 - 2.0) (1.0 - 4.0) (1.0 - 1.0) (1.0 - 3.0) (1.0 - 4.0) Zinc µg/L 35 10 20 20 10 20 (20 - 80) (10 - 70) (10 - 20) (10 - 30) (10 - 30) (10 - 30) Flow L/s NM 200 88 NM 186 NM (36 - 560) (19 - 141) (18 - 966)

Notes: 1. Data presented are in annual medians of monthly samples; except those for faecal coliforms andE. coli which are in annual geometric means. 2. Figures in brackets are annual ranges. 3. NM indicates no measurement taken. 4. cfu - colony forming unit. 5. SP - soluble and particulate fractions i.e. total value. 4 -6 6. Values at or below laboratory reporting limits are presented as laboratory reporting limits (see Table II). 7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. Chapter 4 河

River Water QualityWater inHongRiver Kongin2002 PR2 3 Excellent

N 6 Good

9 Fair Sai Kung 12 Bad

Water QualityWater Index Very Bad 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

Tin Liu Luk Mei Tsuen Hebe Haven Ho Chung River Marina Cove Kai Ho Chung Ham

Nam Pin Wai Nam Wai

Wo Mei Port Shelter Water Control Zone Control Water Shelter Port PR1 3 Excellent

6 Good

9 Fair

12 Bad

Water QualityWater Index Very Bad 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year 7 4 - Figure 4.1 Water Quality Index (WQI) of Ho Chung River and its tributaries Chapter 4 河 River Water QualityWater inHongRiver Kongin2002

PR6 3 N Excellent

6 Good

9 Fair

12 Bad

Water QualityWater Index Very Bad Sha Kok Mei Stream 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Fu Tei Hau

Sha Kok Mei Sha Kok Mei Temporary Housing Area Kap Pin Long Police Sports Tan Cheung Station Ground PR5 Po Lo Che 3

Excellent Zone Control Water Shelter Port

6 Good Sai Kung

9 Fair Sai Kung Hoi 12 Bad

Water QualityWater Index Very Bad 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year 8 4 - Figure 4.2 Water Quality Index (WQI) of Sha Kok Mei Stream and its tributaries Chapter 4 河 River Water QualityWater inHongRiver Kongin2002

PR8 3 N Excellent 6 Good

9 Fair Tai Chung Hau Stream 12 Bad Water QualityWater Index Very Bad 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

Pak Kong Village Ma On Shan Country Park

Wu Lei Tau Lion’s Nature Education Centre

Tai Chung Ta Ho Tun PR7 Hau 3 Excellent Port Shelter Water Control Zone Control Water Shelter Port 6 Good

9 Fair Kau Sai San Tsuen

12 Bad Pak Sha Wan

Water QualityWater Index Very Bad 15 Hebe Haven 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year 9 4 - Figure 4.3 Water Quality Index (WQI) of Tai Chung Hau Stream and its tributaries Chapter 5 Junk Bay Water Control Zone

5.1.3 In 2002, the Water Quality Index 5. Junk Bay (WQI) at the downstream remained as Water Control Zone “excellent”; while the upstream as “fair” (Figure 5.1). The Water Quality Objective (WQO) compliance for BOD5 and COD has increased slightly from that in the previous 5.1 Tseng Lan Shue Stream year. The improvement was brought on by the enforcement efforts coupled with the partial completion of the upgrading of the sewage treatment facilities at Pik Uk Prison and Pik Uk Correctional Institution.

WQO compliance of Tseng Lan Shue Stream

Tseng Lan Shue Stream

WQO % Compliance 1987 2001 2002 pH 91 100 100 Suspended solids 33 100 100 Dissolved oxygen 58 97 97 COD 27 64 78 BOD5 9 39 48 Overall 44 80 85

5.1.4 Because of unsewered premises in 5.1.1 With a catchment of 2.5 km2, the the catchment, the E. coli levels remained 3 km long Tseng Lan Shue Stream flows into high particularly at the upstream stations the inner part of Junk Bay. (Table 5.3). The water quality of Tseng Lan Shue Stream is expected to improve with the 5.1.2 The implementation of the progressive provision of sewerage under the Livestock Waste Control Scheme and Water Port Shelter Sewerage Master Plan (Stage III), Pollution Control Ordinance in the late 1980s which is to be completed by 2010. has resulted in a substantial reduction of aggregate organics and other pollutants in the Tseng Lan Shue Stream (Tables 5.1 and 5.2).

Improving trend of BOD5 in Tseng Lan Shue Stream (JR3) 120

100

(mg/L) 60

5 40

BOD

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

河 River Water Quality in Hong Kong in 2002 5 - 1 Chapter 5 Junk Bay Water Control Zone Table 5.1 River water quality trends in the Junk Bay Water Control Zone based on the results of the Seasonal Kendall Test

Watercourse Tseng Lan Shue Stream Monitoring station JR3 JR6 JR11 Monitoring period* 82-02 82-02 82-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L pH Suspended solids mg/L

BOD5 mg/L COD mg/L Oil & grease mg/L − − E. coli cfu/100mL − − Faecal coliforms cfu/100mL − − − Ammonia-nitrogen mg/L Nitrate-nitrogen mg/L Total Kjeldahl mg/L nitrogen (SP) Ortho-phosphate mg/L Total phosphorus mg/L (SP) Sulphide (SP) mg/L − − − Aluminium µg/L Cadmium µg/L − − − Chromium µg/L − − − Copper µg/L − Lead µg/L Zinc µg/L − − Flow L/s × ×

河 River Water Quality in Hong Kong in 2002 5 - 2 Chapter 5 Junk Bay Water Control Zone Table 5.2 Pollution load reduction in the Tseng Lan Shue Stream catchment of the Junk Bay Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1989 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic 3,064 340 226 114 34 Industrial 2 78 0 78 100 (5) (1) Commercial 0 N.A. N.A. N.A. N.A. WPCO Institutional 4 64 46 18 28

Tseng Lan Sub-total 3,070 482 272 210 44 Shue Stream WDO(2) Livestock 0 19 0 19 100

Total 3,070 501 272 229 46

河 River Water Quality in Hong Kong in 2002 5 - 3 Cha 河 Table 5.3 Summary of water quality monitoring data for Tseng Lan Shue Stream in 2002 River WaterQualit p

Parameter Unit Tseng Lan Shue Stream Ba Junk ter 5 JR3 JR6 JR11 Dissolved oxygen mg/L 6.2 7.4 8.7 (3.8 - 7.1) (6.6 - 7.8) (7.8 - 10.6) pH 7.3 7.9 7.7 (6.5 - 7.6) (7.0 - 8.8) (7.2 - 7.9) Suspended solids mg/L 4 8 3 (2 - 14) (3 - 50) (2 - 18) 5-day Biochemical Oxygen Demand mg/L 10 9 1 y (4 - 23) (3 - 19) (1 - 4) inHon Chemical Oxygen Demand mg/L 21 27 10 (11 - 43) (12 - 50) (4 - 19) Oil & grease mg/L 0.7 1.1 0.5 g (0.5 - 3.6) (0.5 - 1.8) (0.5 - 0.5) Kon Faecal coliforms cfu/100mL 310,000 280,000 8,100 (100,000 - 650,000) (45,000 - 3,500,000) (2,300 - 130,000) g E. coli cfu/100mL 140,000 130,000 2,100 in 2002 (62,000 - 440,000) (20,000 - 3,100,000) (270 - 51,000) Ammonia-nitrogen mg/L 3.35 1.55 0.04 (1.50 - 11.00) (0.49 - 5.80) (0.01 - 0.34) Nitrate-nitrogen mg/L 1.15 2.65 2.60 (0.67 - 2.50) (1.70 - 3.80) (1.20 - 8.50) Total Kjeldahl nitrogen, SP mg/L 4.55 2.95 0.35 (1.90 - 12.00) (0.85 - 8.10) (0.10 - 1.40) Ortho-phosphate mg/L 0.61 1.00 0.48 (0.30 - 1.80) (0.54 - 1.50) (0.21 - 1.30) Total phosphorus, SP mg/L 0.82 1.45 0.53 (0.50 - 2.30) (0.75 - 2.20) (0.24 - 1.50) Sulphide, SP mg/L 0.02 0.02 0.02 (0.02 - 0.08) (0.02 - 0.04) (0.02 - 0.02) Aluminium µg/L 145 185 60 (50 - 280) (110 - 980) (50 - 280) Cadmium µg/L 0.10 0.10 0.10 (0.10 - 0.10) (0.10 - 0.20) (0.10 - 0.10) Chromium µg/L 1.0 1.0 1.0 (1.0 - 1.0) (1.0 - 3.0) (1.0 - 1.0) Copper µg/L 5.0 10.0 4.0 (2.0 - 8.0) (5.0 - 44.0) (2.0 - 8.0) Lead µg/L 1.0 2.0 1.0 y

(1.0 - 2.0) (1.0 - 22.0) (1.0 - 7.0) Water Control Zone Zinc µg/L 30 50 20 (20 - 60) (30 - 80) (10 - 40) Flow L/s NM NM 40 (12 - 320)

Notes: 1. Data presented are in annual medians of monthly samples; except those for faecal coliforms andE. coli which are in annual geometric means. 2. Figures in brackets are annual ranges. 3. NM indicates no measurement taken. 4. cfu - colony forming unit. 5. SP - soluble and particulate fractions i.e. total value. 5 -4 6. Values at or below laboratory reporting limits are presented as laboratory reporting limits (see Table II). 7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. Chapter 5 河 River Water QualityWater inHongRiver Kongin2002

JR6 3 Excellent

N Hebe Hill 6 Good

9 Fair

Pik Uk 12 Bad

Tseng Lan Pak Shek Wo QualityWater Index Very Bad 15 Tseng Lan Shue Stream Shue 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

Sam Long Tsuen

Tseng Kwan O Upper Village Tai Ngau Wu Tseung Kwan O

JR3 JR11 3 3 Excellent Excellent Junk Bay Water ControlZone

6 Good 6 Good

9 Fair 9 Fair

12 Bad 12 Bad

Water QualityWater Index Very Bad QualityWater Index Very Bad 15 15 Junk Bay 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year 5 5 - Figure 5.1 Water Quality Index (WQI) of Tseng Lan Shue Stream and its tributaries Chapter 6 Deep Bay Water Control Zone 02` WQO compliance of River Indus 6. Deep Bay Water Control Zone River Indus WQO % Compliance

1987 2001 2002 6.1 River Indus pH 90 97 97 Suspended solids 0 33 33 Dissolved oxygen 11 81 75 COD 0 33 36 BOD5 5 17 33 Overall 21 52 55

6.1.3 Due to pollution from livestock waste and unsewered villages, the level of E. coli bacteria in the river in 2002 was high, particularly at the downstream station (Table 6.3A). Its Water Quality Index (WQI) also deteriorated from “fair” in 2001 to “bad” in 2002 (Figure 6.1).

6.1.1 The River Indus is one of the largest rivers in the Deep Bay Water Control Zone E. coli level in (WCZ). The river and its tributaries are 49 km River Indus (IN1) in length, covering a catchment area of 43 10,000,000 km2.

1,000,000

6.1.2 Since the declaration of the Deep (cfu/100mL) Bay Water Control Zone in 1990, 89% of the 100,000

organic pollution load have been removed E. coli from the catchment (Table 6.2A). 10,000

Improvement with the dissolved oxygen (DO), 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 nutrient and metal contents in the river (Table Year

6.1A) has resulted in an increase in the Water

Quality Objective (WQO) compliance with 6.1.4 In order to restore the health of the the five key parameters from 21% in 1987 to river, the Western Trunk Sewer was 55% in 2002. But it was still very low constructed under the North District Sewerage compared with other watercourses in the Master Plan in 2002. In the Stage I plan, two territory. villages in the River Indus catchment will be

Improving trend of DO in connected to the sewer by 2005. Improvement

Rive r Indus (IN2) of river water quality is expected with 8 continuous enforcement effort and gradual

6 provision of public sewer to the unsewered

villages.

(mg/L) 4

DO 2

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

河 River Water Quality in Hong Kong in 2002 6 - 1 Chapter 6 Deep Bay Water Control Zone

6.2 River Beas Improving trend of DO in Rive r Be as (RB1) 10

(mg/L)

4 DO

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year WQO compliance of River Beas

River Beas 6.2.1 The River Beas is a main tributary WQO % Compliance of River Indus within the North District. Since 1987 2001 2002 the late 80s, there has been a significant pH 94 97 94 increase in DO, as well as a reduction in BOD Suspended solids 0 0 67 loading and pollutants in the river (Tables Dissolved oxygen 6 97 92 COD 0 22 25 6.1A & 6.2A). These have resulted in the BOD5 0 6 19 upgrading of WQI from “very bad” in the 80s Overall 20 44 59 to “fair” in 2002 (Figure 6.2).

6.2.2 In 2002, the overall compliance E. coli level in with the key WQOs was 59%, showing an River Beas (RB3) increase of 15% from that in 2001. There was 10,000,000 a marked improvement in the compliance with the suspended solid WQO, although the 1,000,000 compliance for COD and BOD were still low

5 (cfu/100mL) and the E. coli levels in the river remained 100,000 high (Table 6.3A). E. coli 10,000

6.2.3 The organic and faecal pollution in 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 River Beas was mainly attributed to the Year discharges from problematic livestock farms, unsewered villages, and rural developments in 6.3 River Ganges the catchment. Under the North District Sewerage Master Plan Stage I, six villages in River Beas catchment area are planned to be provided with public sewerage in 2005. Vigorous legislative enforcement coupled with sewerage construction will help alleviate the pollution problem in the river.

河 River Water Quality in Hong Kong in 2002 6 - 2 Chapter 6 Deep Bay Water Control Zone

6.3.1 Measuring 31 km in length and WQO compliance of River Ganges 2 covering an area of 18 km , the River Ganges joins Shenzhen River before flowing into River Ganges inner Deep Bay. WQO % Compliance 6.3.2 In the last decade, River Ganges has 1987 2001 2002 shown a very substantial increase in DO and pH 95 100 100 Suspended solids 33 67 67 decreases in pollutants including E. coli Dissolved oxygen 38 89 81 bacteria (Tables 6.1A and 6.2A). In 2002, the COD 17 36 33 WQI at the upstream stretch was graded BOD5 33 28 17 “good”; while the lower reaches remained Overall 43 64 59 “bad” (Figure 6.3). The overall compliance with the key WQOs was 59%.

Improving trend of DO in 6.4 Yuen Long Creek Rive r Gange s (GR1) 6

(mg/L)

DO 2

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year E. coli level in River Ganges (GR1) 10,000,000 6.4.1 Yuen Long Creek is around 60 km long and covers an area of 27 km2. The lower 1,000,000 part is intertidal, which impedes the removal (cfu/100mL) of pollutants from the creek.

coli E.

100,000 6.4.2 The improving trends in DO, E. coli and many other parameters since mid 80s 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year (Table 6.1B) have resulted in the increase of compliance with the key WQOs of Yuen Long 6.3.3 As in most rural areas in the North Creek to 43% in 2002. However, this was still District, polluted discharges from problematic very low and unsatisfactory. livestock farms and unsewered villages were major pollution sources which have resulted in 6.4.3 The WQI of Yuen Long Creek was the unsatisfactory river water quality. Under “bad” in 2002 and the E. coli levels were very the North East New Territories (NENT) high (Figure 6.4 and Table 6.3B). The major Landfill Village Sewerage Plan, public sewer pollution sources were domestic sewage from will be provided to villages in the catchment unsewered villages and illegal discharges of River Ganges by 2006. It is anticipated that from livestock farms in the catchment. the river condition should be improved with continuous legislative control against polluters and provision of public sewer to villages.

河 River Water Quality in Hong Kong in 2002 6 - 3 Chapter 6 Deep Bay Water Control Zone

Improving trend of DO in 6.5 Kam Tin River Yuen Long Creek (YL3) 6

(mg/L)

DO 2

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year E. coli level in Yuen Long Creek (YL3) 100,000,000 6.5.1 With a catchment area of 44 km2, 10,000,000 the 50 km Kam Tin River passes through the urban towns of Kam Tin and Yuen Long (cfu/100mL) 1,000,000 before entering Deep Bay.

coli E. 100,000 6.5.2 Although the seriously polluted

1994 1995 1996 1997 1998 1999 2000 2001 2002 Kam Tin River has shown long-term reduction Year in organic and other pollution parameters WQO compliance of Yuen Long Creek (Table 6.1B), the overall compliance with the key WQOs in 2002 was exceedingly low at Yuen Long Creek 27%, showing a decrease of 12% from that in 2001. Marked deteriorations in DO and BOD5 WQO % Compliance compliance were detected. The WQI at the 1987 2001 2002 station KT2 slipped from “bad” to “very bad” pH 98 94 98 and E. coli was elevated to 1,400,000 Suspended solids 0 25 25 Dissolved oxygen 0 71 81 cfu/100mL in 2002 (Figure 6.4 and Table COD 0 27 13 6.3B). BOD5 0 9 0 Overall 20 45 43

Improving trend of BOD5 in Kam Tin River (KT1) 150 6.4.4 To further reduce pollution in Yuen

Long Creek, enforcement efforts will continue 100 and sewerage is planned to be provided for the (mg/L) villages under the Yuen Long and Kam Tin 5 50 Sewerage Master Plan between 2003 and BOD 2009.

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

河 River Water Quality in Hong Kong in 2002 6 - 4 Chapter 6 Deep Bay Water Control Zone

WQO compliance of Kam Tin River Improving trend of BOD5 in Tin Shui Wai Nullah (TSR2) 40 Kam Tin River

WQO % Compliance 30 1987 2001 2002 (mg/L) 20

pH 96 100 100 5 Suspended solids 0 0 0 BOD Dissolved oxygen 0 75 33 10 COD 0 4 0 BOD5 0 15 0 0 Overall 19 39 27

1994 1995 1996 1997 1998 1999 2000 2001 2002 Year 6.5.3 The major pollution sources in the catchment were the unsewered village houses, 6.6.2 In 2002, the WQI of the upstream illegal discharges from problematic livestock station remained “good”; and the downstream farms and increased livestock population. To station has improved from “bad” to “fair” help alleviating the pollution problem of Kam (Figure 6.5). The improvement in 2002 could Tin River, EPD has further tightened the be attributed to the connection of two housing enforcement against illegal dischargers. New estates to the public sewer and the closing sewerage network is planned to be provided down of a food factory which made for the catchment under the Yuen Long and discharges into the nullah. Kam Tin Sewerage Master Plan Review by the year 2008. E. coli level in Tin Shui Wai Nullah (TSR2) 10,000,000

6.6 Tin Shui Wai Nullah 1,000,000

100,000 (cfu/100mL) 10,000 E. coli E.

1,000

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

6.6.3 The WQO compliance rates for the pH, DO and COD objectives in 2002 have shown a decrease largely due to the illegal industrial discharges. To curb pollution in the nullah, enforcement efforts would be further

6.6.1 Tin Shui Wai Nullah is a concrete enhanced on the industrial establishments as channel draining into inner Deep Bay. In the well as on livestock farms in the area. last decade, the nullah has shown a significant reduction in organic, E. coli and other pollutants (Tables 6.1B and 6.2B).

河 River Water Quality in Hong Kong in 2002 6 - 5 Chapter 6 Deep Bay Water Control Zone

WQO compliance of Tin Shui Wai Nullah Improving trend of DO in Fairview Park Nullah (FVR1) 8 Tin Shui Wai Nullah

WQO % Compliance 6

1994 2001 2002 4 pH 88 92 67 (mg/L) Suspended solids 0 50 50 Dissolved oxygen 54 92 83 DO 2 COD 42 96 79 BOD5 4 50 58 0 Overall 38 76 68 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year 6.6.4 Discharges from unsewered villages were a major source of pollution in the E. coli level in catchment. To tackle the problem, new Fairview Park Nullah (FVR1) 10,000,000 sewerage network is planned to be constructed under the Yuen Long and Kam Tin Sewerage 1,000,000 Master Plan Review by around 2009.

(cfu/100mL) 100,000

6.7 Fairview Park Nullah coli E. 10,000

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

6.7.3 Due to the pollution from unsewered villages and illegal discharges of livestock waste, there was some water quality deterioration in Fairview Park Nullah in 2002. The WQO compliance for BOD5 and COD dropped by 18% and 33% respectively; the compliance with the suspended solid objective remained at 0%. The WQI of the watercourse has been downgraded from “fair” to “bad” and 6.7.1 The Fairview Park Nullah is a the E. coli level was very high (Figure 6.5 and concrete channel which passes through Table 6.3C). Fairview Park before entering the inner Deep Bay. 6.7.4 To curb pollution in the nullah, EPD has further stepped up enforcement actions 6.7.2 Since the implementation of against the problematic livestock farms. New pollution control legislation in the late 1980s, sewerage network is planned to be provided to notable improvements in DO, E. coli and the river catchment under the Yuen Long and other river water quality parameters have been Kam Tin Sewerage Master Plan towards the detected (Table 6.1C). end of the decade.

河 River Water Quality in Hong Kong in 2002 6 - 6 Chapter 6 Deep Bay Water Control Zone

WQO compliance of Fairview Park Nullah 6.8.1 The minor streams in the outer Deep Bay: Sheung Pak Nai, Pak Nai, Ha Pak Nai, Fairview Park Nullah Tai Shui Hang and Tsang Kok Streams are WQO % Compliance largely pristine and free from point source pollution (Tables 6.2C and D). Similar to the 1994 2001 2002 pH 100 100 100 previous year, they have achieved a 100% Suspended solids 0 0 0 compliance with the key WQOs with an Dissolved oxygen 0 92 83 “excellent” WQI in 2002 (Figures 6.6 and 6.7). COD 8 83 50 BOD5 8 18 0 There were also notable long-term Overall 23 59 47 improvements in many water quality parameters in the streams (Table 6.1C).

Improving trend of COD in 6.8 Ngau Hom Sha, Sheung Pak Nai, Pak Nai Stream (DB3) 80 Pak Nai, Ha Pak Nai, Tai Shui

Hang and Tsang Kok Streams 60

(mg/L) 40

Ha Pak Nai Stream

COD 20

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

WQO compliance of Sheung Pak Nai Stream

Sheung Pak Nai Stream

WQO % Compliance 1990 2001 2002 pH 92 100 100 Suspended solids 100 100 100 Dissolved oxygen 50 100 100 COD 67 100 100 Ngau Hom Sha Stream BOD5 33 100 100 Overall 68 100 100

WQO compliance of Pak Nai Stream

Pak Nai Stream

WQO % Compliance 1990 2001 2002 pH 92 100 100 Suspended solids 0 100 100 Dissolved oxygen 42 100 100 COD 58 100 100 BOD5 8 100 100 Overall 40 100 100

河 River Water Quality in Hong Kong in 2002 6 - 7 Chapter 6 Deep Bay Water Control Zone

WQO compliance of Ha Pak Nai Stream Improving trend of DO in Ngau Hom Sha Str e am (DB6) 12 Ha Pak Nai Stream WQO % Compliance 8 1990 2001 2002 (mg/L)

pH 92 100 100

Suspended solids 100 100 100 DO 4 Dissolved oxygen 100 100 100 COD 92 100 100 BOD 75 100 100 5 0 Overall 92 100 100 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

WQO compliance of Tai Shui Hang Stream WQO compliance of Ngau Hom Sha Stream

Tai Shui Hang Stream Ngau Hom Sha Stream WQO % Compliance WQO % Compliance 1990 2001 2002 1990 2001 2002 pH 100 100 100 pH 92 100 100 Suspended solids 100 100 100 Suspended solids 0 100 100 Dissolved oxygen 100 100 100 Dissolved oxygen 0 92 92 COD 100 100 100 COD 0 83 75 BOD5 75 100 100 BOD5 0 67 58 Overall 95 100 100 Overall 18 88 85

WQO compliance of Tsang Kok Stream

Tsang Kok Stream 6.9 Pollution control measures in the WQO % Compliance Deep Bay catchment 1990 2001 2002 pH 83 100 100 Suspended solids 0 100 100 6.9.1 To reduce pollution in the Deep Bay Dissolved oxygen 83 100 100 COD 58 100 100 catchment, the following improvement BOD5 42 100 100 measures have been taken: Overall 53 100 100 Enforcement of the Waste Disposal Ordinance including implementing the 6.8.2 The Ngau Hom Sha Stream flows Chemical Waste Control Scheme, revised from the Castle Peak Range into outer Deep Livestock Waste Control Scheme and Bay. Similar to the other minor streams, it has Flytipping Control. experienced a marked water quality improvement in the last decade (Table 6.1C). Enforcement of the Water Pollution However, the WQI of the stream remained as Control Ordinance. “fair” in 2002 with a decrease in the compliance with the COD and BOD5 Implementation of sewerage projects objectives (Figure 6.7). The deterioration was including the North District Sewerage mainly caused by illegal discharges from pig Master Plans (SMPs) and the Yuen Long / farms. Vigorous enforcement action will Kam Tin District SMP. continue to curb this pollution source.

河 River Water Quality in Hong Kong in 2002 6 - 8 Chapter 6 Deep Bay Water Control Zone

6.9.2 New public sewerage will be built Yuen Long & Kam Tin SMP Works for 16 villages in the Ta Kwu Ling area under Yuen Long & Kam Tin the North East New Territories (NENT) Stage II Stage III SMP Landfill Village Sewerage Programme Tentative Implementation between 2003 and 2006. 1999–2007 2003–2009 Date (year)

Estimated population to be 6.9.3 The sewerage works in the North 61,000 31,000 provided with sewer (no.) District are being constructed in two stages, Under the Stage I works, 39 villages with Estimated pollution load to approximately 41,000 people are planned to be collected by sewer 3,400 1,700 (kg BOD /day) be sewered by 2009. The sewer network is planned to extend to another 35 villages of around 20,000 people in the Stage II works. 6.9.6 The implementation of the sewerage On-site treatment and sewage disposal construction works under the Yuen Long and facilities are also planned to be built for Kam Tin SMP Review, has been planned to remote villages by around 2011. commence in late 2005. This will provide sewerage for an additional 621,000 inhabitants

in the Yuen Long and Kam Tin areas by the 6.9.4 To cope with further population year 2010. growth and developments, additional sewage works, as recommended by the North District Yuen Long & Kam Tin SMP Review and Tolo Harbour SMPs Review, are planned for implementation between 2007 and 2011. Yuen Long & Kam Tin Stage I Stage II The new sewerage is expected to serve SMP Review another 4,700 inhabitants in the North District. Tentative Implementation 2005–2008 2006–2010 Date (year) North District SMP Works Estimated population 216,000 405,000 provided with sewer (no.) North District Stage I Stage II SMP Estimated pollution load collected by sewer 11,800 22,300 Tentative Implementation 1999–2004a 2007–2012 /(kg BOD /day) Date (year) 2002–2009b

Estimated population 4,480a 20,000 provided with sewer (no.) 36,370b

Estimated pollution load 246a collected by sewer 1,100 2,000b (kg BOD /day) a – Phase I b – Phase II

6.9.5 Under the Yuen Long and Kam Tin SMP, new sewer will be constructed for about 92,000 people. Stage III of the works for providing sewerage to the Au Tau and Yuen Long South areas has commenced in 2003.

河 River Water Quality in Hong Kong in 2002 6 - 9 Chapter 6 Deep Bay Water Control Zone Table 6.1A River water quality trends in the Deep Bay Water Control Zone based on the results of the Seasonal Kendall Test

Watercourse River Indus River Beas River Ganges Monitoring station IN1 IN2 IN3 RB1 RB2 RB3 GR1 GR2 GR3 Monitoring period* 87-02 87-02 87-02 84-02 84-02 84-02 87-02 87-02 87-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L − − pH − − − Suspended solids mg/L − − − −

BOD5 mg/L − COD mg/L − Oil & grease mg/L − − − − − − E. coli cfu/100mL − Faecal coliforms cfu/100mL − − Ammonia-nitrogen mg/L − Nitrate-nitrogen mg/L − − − Total Kjeldahl mg/L nitrogen (SP) Ortho-phosphate mg/L Total phosphorus mg/L (SP) Sulphide (SP) mg/L − − − Aluminium µg/L − − − − − Cadmium µg/L − − − − − − − Chromium µg/L − − − − − − − Copper µg/L − − − Lead µg/L − − Zinc µg/L − − − − − Flow L/s − × − − − − −

河 River Water Quality in Hong Kong in 2002 6 - 10 Chapter 6 Deep Bay Water Control Zone Table 6.1B River water quality trends in the Deep Bay Water Control Zone based on the results of the Seasonal Kendall Test

Tin Shui Wai Watercourse Yuen Long Creek Kam Tin River Nullah Monitoring station YL1 YL2 YL3 YL4 KT1 KT2 TSR1 TSR2 Monitoring period* 84-02 84-02 84-02 84-02 84-02 84-02 93-02 93-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L − pH − − Suspended solids mg/L − − − − − −

BOD5 mg/L − COD mg/L − Oil & grease mg/L − − − − E. coli cfu/100mL − − − − Faecal coliforms cfu/100mL − − − − − Ammonia-nitrogen mg/L − Nitrate-nitrogen mg/L − − − − − Total Kjeldahl mg/L nitrogen (SP) Ortho-phosphate mg/L Total phosphorus mg/L (SP) Sulphide (SP) mg/L − Aluminium µg/L − − − − − − − − Cadmium µg/L − − − − − − − Chromium µg/L − − − Copper µg/L − − − − Lead µg/L − − − − − − Zinc µg/L − − − Flow L/s − − − − × −

河 River Water Quality in Hong Kong in 2002 6 - 11 Chapter 6 Deep Bay Water Control Zone Table 6.1C River water quality trends in the Deep Bay Water Control Zone based on the results of the Seasonal Kendall Test

Ngau Fairview Ha Pak Tai Shui Sheung Tsang Pak Nai Hom Watercourse Park Nai Hang Pak Nai Kok Stream Sha Nullah Stream Stream Stream Stream Stream Monitoring station FVR1 DB1 DB2 DB3 DB5 DB6 DB8 Monitoring period* 93-02 89-02 89-02 89-02 89-02 89-02 89-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L pH − − − − Suspended solids mg/L −

BOD5 mg/L COD mg/L − Oil & grease mg/L − − − − − − E. coli cfu/100mL − − − − Faecal coliforms cfu/100mL − − − − − − Ammonia-nitrogen mg/L − − − Nitrate-nitrogen mg/L − − − Total Kjeldahl mg/L nitrogen (SP) Ortho-phosphate mg/L − Total phosphorus mg/L (SP) Sulphide (SP) mg/L − − − − − Aluminium µg/L − − − − Cadmium µg/L − − − − − − Chromium µg/L − − − − − − − Copper µg/L − − − − − Lead µg/L − Zinc µg/L − − − − − − Flow L/s × − − − − −

河 River Water Quality in Hong Kong in 2002 6 - 12 Chapter 6 Deep Bay Water Control Zone Table 6.2A Pollution load reductions in the river catchments of the Deep Bay Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1990 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic 8,000 835 825(6) 10 1 Industrial 45 1,012 14 998 99 (1) Commercial 45 289 5 284 98 WPCO Institutional 52 701 300 401 57 River Sub-total 8,142 2,837 1,144 1,693 60 Indus WDO(2) Livestock 15 7,540 41 7,499 99

Total 8,157 10,377 1,185 9,192 89

Domestic 4,000 235 412(6) N.A. (5) N.A. Industrial 47 3,470 42 3,428 99 Commercial 21 130 2 128 98 WPCO Institutional 81 444 50 394 89 River Sub-total 4,149 4,279 506 3,773 88 Beas WDO Livestock 19 9,294 75 9,219 99

Total 4,168 13,573 581 12,992 96

Domestic 2,000 200 192 8 4 Industrial 10 283 7 276 98 Commercial 10 110 1 109 99 WPCO Institutional 24 79 3 76 96 River Sub-total 2,044 672 203 469 70 Ganges WDO Livestock 54 7,165 131 7,034 98

Total 2,098 7,837 334 7,503 96

河 River Water Quality in Hong Kong in 2002 6 - 13 Chapter 6 Deep Bay Water Control Zone Table 6.2B Pollution load reductions in the river catchments of the Deep Bay Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1990 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic N.A.(5) 1,562 516 1,046 67 Industrial 52 3,545 20 3,525 99 (1) Commercial 34 540 11 529 98 WPCO Institutional 29 267 372(6) N.A. N.A.

Yuen Long Sub-total 115 5,914 919 4,995 84 Creek WDO(2) Livestock 77 13,437 455(7) 12,982 97

Total 192 19,351 1,374 17,977 93

Domestic N.A. 620 620 N.A. N.A. Industrial 44 1,156 20 1,136 98 Commercial 82 61 66(8) N.A. N.A. WPCO Institutional 40 384 16 368 96 Kam Tin Sub-total 166 2,221 722 1,499 67 River WDO Livestock 120 17,718 847(7) 16,871 95

Total 286 19,939 1,569 18,370 92

Domestic N.A. 579 474 105 18 Industrial 75  22   Commercial 87  2,752 23  2,703  98 WPCO Institutional 20  4   Tin Shui Wai Sub-total 182 3,331 523 2,808 84 Nullah WDO Livestock 81 8,202 259(7) 7,943 97

Total 263 11,533 782 10,751 93

Notes: (1) WPCO : Water Pollution Control Ordinance. (2) WDO : Waste Disposal Ordinance. (3) Data shown in these two columns reflect the situation as at the end of 2002. (4) Pollution from effluent discharges in the river catchments of the Deep Bay WCZ has been progressively brought under legislative control since the declaration of the WCZ on 1 December 1990. (5) N.A. : Not applicable or data not available. (6) The increase in BOD load was due to the population growth and the corresponding increase in the quantity of treated effluent discharged from Yuen Long Sewage Treatment Works into Yuen Long Creek. (7) The increase in pollution load as compared to 2001 is due to increase in the number of problematic livestock farms in the catchment. (8) The increase in pollution load as compared to 2001 is due to increase in the number of commercial premises in the catchment.

河 River Water Quality in Hong Kong in 2002 6 - 14 Chapter 6 Deep Bay Water Control Zone Table 6.2C Pollution load reductions in the river catchments of the Deep Bay Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1990 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic N.A.(5) 251 42 209 83 Industrial 8 385 3 382 99 (6) (1) Commercial 13 19 4 15 79 WPCO Institutional 11 76 1 75 99

Fairview Sub-total 32 731 50 681 93 Park Nullah WDO(2) Livestock 16 2,857 336(7) 2,521 88

Total 48 3,588 386 3,202 89 Domestic 0 1 1 0 0 Industrial 0 0 0 0 0 Commercial 0 0 0 0 0 WPCO Institutional 1 0 0 0 0

Ngau Hom Sub-total 1 1 1 0 0 Sha Stream WDO Livestock 2 356 2 354 99

Total 3 357 3 354 99 Domestic 0 2 2 0 0 Industrial 0 0 0 0 0 Commercial 0 0 0 0 0 WPCO Institutional 0 0 0 0 0

Sheung Pak Sub-total 0 2 2 0 0 Nai Stream WDO Livestock 4 55 32 23 42

Total 4 57 34 23 40

Notes: (1) WPCO : Water Pollution Control Ordinance. (2) WDO : Waste Disposal Ordinance. (3) Data shown in these two columns reflect the situation as at the end of 2002. (4) Pollution from effluent discharges in the river catchments of the Deep Bay WCZ has been progressively brought under legislative control since the declaration of the WCZ on 1 December 1990. (5) N.A. :Not applicable or data not available. (6) Decrease in BOD loading was due to higher compliance in discharge standards by commercial dischargers as compared to 2001. (7) The increase in pollution load as compared to 2001 is due to increase in the number of problematic livestock farms in the catchment.

河 River Water Quality in Hong Kong in 2002 6 - 15 Chapter 6 Deep Bay Water Control Zone Table 6.2D Pollution load reductions in the river catchments of the Deep Bay Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1990 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic 0 1 1 0 0 Industrial 0 105 0 105 100 (1) Commercial 0 0 0 0 0 WPCO Institutional 0 0 0 0 0

Ha Pak Nai Sub-total 0 106 1 105 99 Stream WDO(2) Livestock 1 46 1 45 98

Total 1 152 2 150 99 Domestic 0 1 1 0 0 Industrial 0 0 0 0 0 Commercial 0 0 0 0 0 WPCO Institutional 0 0 0 0 0

Pak Nai Sub-total 0 1 1 0 0 Stream WDO Livestock 2 517 0 517 100

Total 2 518 1 517 99

河 River Water Quality in Hong Kong in 2002 6 - 16 Cha 河 Table 6.3A Summary of water quality monitoring data for the River Indus, the River Beas and the River Ganges in 2002 Sampling Station River WaterQualit p

Parameter Unit River Indus River Beas Dee River Ganges ter 6 IN1 IN2 IN3 RB1 RB2 RB3 GR1 GR2 GR3 Dissolved oxygen mg/L 3.1 7.4 8.3 8.4 7.5 5.5 4.9 4.3 6.3 (1.8 - 6.3) (3.3 - 9.1) (7.7 - 10.2) (5.0 - 11.3) (5.9 - 9.0) (3.2 - 15.6) (2.7 - 7.3) (1.5 - 6.1) (4.4 - 8.1) pH 7.2 7.2 7.4 7.8 7.3 7.2 7.3 7.1 7.1 (6.9 - 7.4) (6.6 - 7.7) (7.1 - 8.5) (7.2 - 9.3) (7.0 - 7.8) (7.1 - 8.5) (6.9 - 7.8) (6.8 - 7.3) (6.8 - 7.3) Suspended solids mg/L 31 67 5 11 13 27 34 12 12 (13 - 110) (22 - 330) (3 - 32) (6 - 62) (4 - 110) (11 - 130) (17 - 370) (5 - 29) (5 - 300) 5-day Biochemical Oxygen Demand mg/L 15 3 3 6 5 4 19 16 3 y (4 - 39) (1 - 15) (2 - 9) (2 - 21) (2 - 21) (2 - 68) (5 - 77) (4 - 33) (1 - 20) inHon Chemical Oxygen Demand mg/L 33 16 17 22 19 24 53 48 9 (15 - 63) (5 - 29) (8 - 32) (5 - 48) (8 - 42) (9 - 55) (15 - 130) (19 - 72) (3 - 20) Oil & grease mg/L 0.6 0.5 0.5 0.6 0.5 0.5 0.9 1.8 0.5

g (0.5 - 1.0) (0.5 - 0.7) (0.5 - 0.7) (0.5 - 1.1) (0.5 - 0.9) (0.5 - 1.6) (0.5 - 6.8) (0.5 - 3.1) (0.5 - 0.6) Kon Faecal coliforms cfu/100mL 970,000 94,000 15,000 63,000 68,000 220,000 230,000 300,000 48,000 (10,000 - 8,000,000) (30,000-410,000) (4,200 - 110,000) (7,700 - 340,000) (7,000 - 560,000) (29,000 - 2,000,000) (19,000 - 990,000) (18,000 - 2,900,000) (6,100 - 560,000) g E. coli cfu/100mL 390,000 16,000 4,700 18,000 31,000 52,000 110,000 78,000 1,800 in 2002 (5,000 - 4,100,000) (1,600-90,000) (800 - 100,000) (1,300 - 89,000) (3,400 - 280,000) (5,900 - 1,500,000) (11,000 - 680,000) (5,300 - 340,000) (220 - 34,000) Ammonia-nitrogen mg/L 7.75 1.05 0.82 1.20 4.00 3.55 23.50 5.70 0.16 (1.20 - 17.00) (0.29 - 4.10) (0.23 - 7.30) (0.22 - 9.30) (0.51 - 9.30) (0.90 - 9.80) (5.10 - 85.00) (0.91 - 23.00) (0.03 - 0.45) Nitrate-nitrogen mg/L 0.84 1.15 1.04 0.45 0.94 1.05 0.12 0.08 0.12 (0.01 - 3.70) (0.50 - 1.70) (0.43 - 1.90) (0.16 - 1.10) (0.38 - 1.80) (0.02 - 3.10) (0.01 - 1.00) (0.01 - 1.90) (0.04 - 0.17) Total Kjeldahl nitrogen, SP mg/L 10.10 1.70 1.20 2.45 5.35 5.15 26.50 8.25 0.55 (1.70 - 22.00) (0.54 - 4.70) (0.51 - 9.70) (0.61 - 13.00) (0.83 - 10.00) (1.30 - 13.00) (6.90 - 91.00) (1.90 - 25.00) (0.11 - 1.20) Ortho-phosphate mg/L 0.96 0.05 0.49 0.57 0.57 0.50 6.90 4.40 0.01 (0.01 - 1.20) (0.01 - 0.12) (0.14 - 1.30) (0.16 - 1.50) (0.19 - 0.98) (0.24 - 1.00) (1.20 - 19.00) (1.30 - 20.00) (0.01 - 0.03) Total phosphorus, SP mg/L 1.55 0.33 0.68 0.89 0.96 1.25 8.45 5.75 0.03 (0.34 - 2.20) (0.17 - 0.56) (0.30 - 1.90) (0.25 - 2.10) (0.30 - 1.60) (0.47 - 1.90) (1.70 - 21.00) (1.50 - 19.00) (0.02 - 0.34) Sulphide, SP mg/L 0.03 0.02 0.02 0.02 0.02 0.02 0.05 0.04 0.02 (0.02 - 0.57) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.09) (0.02 - 0.06) (0.02 - 0.26) (0.02 - 0.80) (0.02 - 0.48) (0.02 - 0.02) Aluminium µg/L 240 265 60 90 85 175 170 100 85 (110 - 680) (110 - 770) (50 - 100) (50 - 370) (50 - 450) (50 - 680) (50 - 640) (50 - 260) (50 - 1,000) Cadmium µg/L 0.15 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 (0.10 - 1.20) (0.10 - 0.30) (0.10 - 0.10) (0.10 - 0.10) (0.10 - 0.20) (0.10 - 0.40) (0.10 - 0.40) (0.10 - 0.20) (0.10 - 0.60) Chromium µg/L 3.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (1.0 - 7.0) (1.0 - 2.0) (1.0 - 1.0) (1.0 - 2.0) (1.0 - 2.0) (1.0 - 3.0) (1.0 - 9.0) (1.0 - 4.0) (1.0 - 1.0)

Copper µg/L 7.5 5.0 8.0 5.5 6.0 6.0 12.5 5.5 2.0 p (5.0 - 37.0) (3.0 - 16.0) (4.0 - 18.0) (2.0 - 8.0) (4.0 - 24.0) (2.0 - 25.0) (1.0 - 35.0) (2.0 - 11.0) (1.0 - 16.0) Ba Lead µg/L 3.0 7.5 1.0 1.5 1.0 3.5 2.0 1.0 1.5 y

(2.0 - 8.0) (3.0 - 34.0) (1.0 - 1.0) (1.0 - 5.0) (1.0 - 6.0) (1.0 - 9.0) (1.0 - 8.0) (1.0 - 5.0) (1.0 - 25.0) Water Control Zone Zinc µg/L 85 440 30 20 30 90 60 35 20 (50 - 12,000) (90 - 6,300) (20 - 70) (10 - 60) (10 - 90) (40 - 350) (10 - 400) (10 - 90) (10 - 100) Flow L/s NM NM 33 183 388 342 95 49 30 (7 - 372) (55 - 608) (12 - 3,720) (198 - 4,800) (22 - 400) (12 - 168) (18 - 60)

6 -17 5. SP - soluble and particulate fractions i.e. total value. 6. Values at or below laboratory reporting limits are presented as laboratory reporting limits (see Table II). 7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. Cha 河 Table 6.3B Summary of water quality monitoring data for Yuen Long Creek, Kam Tin River and Tin Shui Wai Nullah in 2002 Sampling Station River WaterQualit p

Parameter Unit Yuen Long Creek Dee Kam Tin River Tin Shui Wai Nullah ter 6 YL1 YL2 YL3 YL4 KT1 KT2 TSR1 TSR2 Dissolved oxygen mg/L 5.7 7.7 4.9 3.9 4.1 3.1 4.5 10.5 (3.5 - 7.8) (5.2 - 10.5) (2.8 - 6.4) (2.4 - 5.3) (2.5 - 6.6) (1.8 - 6.3) (2.3 - 8.1) (8.0 - 13.5) pH 7.4 7.5 7.5 7.4 7.4 7.4 7.5 9.2 (6.8 - 7.7) (6.9 - 7.9) (6.8 - 7.6) (6.9 - 8.9) (6.9 - 7.6) (7.0 - 7.6) (7.2 - 8.1) (7.3 - 9.8) Suspended solids mg/L 17 22 55 130 48 145 21 12 (8 - 58) (9 - 94) (12 - 270) (48 - 5,100) (10 - 140) (18 - 340) (8 - 290) (5 - 27) 5-day Biochemical Oxygen Demand mg/L 14 9 47 81 18 108 10 1 y (7 - 300) (5 - 15) (17 - 110) (33 - 500) (8 - 120) (8 - 390) (3 - 42) (1 - 4) inHon Chemical Oxygen Demand mg/L 29 24 58 68 31 135 28 7 (15 - 420) (14 - 31) (28 - 110) (31 - 100) (22 - 110) (21 - 630) (8 - 58) (2 - 12) Oil & grease mg/L 0.6 0.5 2.0 4.5 0.8 7.1 0.6 0.5

g (0.5 - 4.0) (0.5 - 1.1) (0.5 - 21.0) (0.5 - 15.0) (0.5 - 5.9) (0.5 - 44.0) (0.5 - 2.6) (0.5 - 0.7) Kon Faecal coliforms cfu/100mL 400,000 200,000 1,500,000 4,600,000 470,000 1,900,000 1,900,000 18,000 (170,000 - 1,900,000) (84,000 - 610,000) (800,000 - 3,600,000) (1,200,000 - 23,000,000) (65,000 - 1,700,000) (290,000 - 11,000,000) (370,000 - 46,000,000) (1,400 - 130,000) g E. coli cfu/100mL 260,000 92,000 770,000 1,600,000 150,000 1,400,000 930,000 6,700 in 2002 (90,000 - 1,700,000) (39,000 - 410,000) (420,000 - 2,100,000) (820,000 - 5,600,000) (40,000 - 490,000) (220,000 - 9,100,000) (100,000 - 26,000,000) (600 - 100,000) Ammonia-nitrogen mg/L 10.05 7.65 15.50 6.75 9.30 35.50 3.75 0.10 (3.30 - 110.00) (2.60 - 14.00) (4.70 - 21.00) (4.60 - 11.00) (6.80 - 31.00) (6.10 - 72.00) (0.65 - 8.30) (0.02 - 0.53) Nitrate-nitrogen mg/L 1.10 1.04 0.27 0.02 0.54 0.02 0.74 1.08 (0.01 - 4.90) (0.52 - 12.00) (0.01 - 1.80) (0.01 - 1.20) (0.01 - 3.50) (0.01 - 0.54) (0.02 - 3.30) (0.54 - 2.30) Total Kjeldahl nitrogen, SP mg/L 13.00 8.65 21.00 11.00 16.00 46.50 5.05 0.28 (4.30 - 120.00) (3.50 - 16.00) (7.00 - 27.00) (7.70 - 16.00) (8.30 - 38.00) (7.30 - 110.00) (1.10 - 11.00) (0.06 - 0.96) Ortho-phosphate mg/L 2.15 1.75 2.55 0.98 2.65 8.00 0.32 0.06 (0.74 - 11.00) (0.63 - 2.40) (0.70 - 3.50) (0.44 - 1.30) (1.30 - 5.40) (1.10 - 14.00) (0.09 - 0.98) (0.02 - 0.19) Total phosphorus, SP mg/L 2.35 2.05 3.60 1.70 3.30 9.85 0.76 0.09 (0.87 - 13.00) (0.82 - 2.90) (1.00 - 4.90) (1.20 - 2.20) (2.10 - 7.20) (1.50 - 23.00) (0.18 - 2.00) (0.03 - 0.26) Sulphide, SP mg/L 0.03 0.02 0.05 0.02 0.05 0.22 0.03 0.02 (0.02 - 0.20) (0.02 - 0.02) (0.02 - 0.34) (0.02 - 0.09) (0.02 - 0.31) (0.02 - 0.75) (0.02 - 0.13) (0.02 - 0.05) Aluminium µg/L 165 150 300 540 295 340 240 280 (50 - 350) (100 - 660) (150 - 670) (220 - 3,900) (140 - 860) (60 - 690) (90 - 1,700) (90 - 440) Cadmium µg/L 0.15 0.10 0.30 0.10 0.20 0.45 0.10 0.10 (0.10 - 0.50) (0.10 - 0.20) (0.10 - 0.50) (0.10 - 0.30) (0.10 - 0.40) (0.10 - 0.90) (0.10 - 1.10) (0.10 - 0.10) Chromium µg/L 1.0 1.0 2.5 2.0 1.0 5.5 1.0 1.0 (1.0 - 4.0) (1.0 - 1.0) (1.0 - 7.0) (1.0 - 8.0) (1.0 - 3.0) (1.0 - 59.0) (1.0 - 31.0) (1.0 - 1.0)

Copper µg/L 11.5 8.0 22.0 10.0 25.0 26.5 9.0 2.0 p (5.0 - 69.0) (4.0 - 16.0) (9.0 - 87.0) (6.0 - 50.0) (14.0 - 120.0) (8.0 - 120.0) (2.0 - 22.0) (1.0 - 4.0) Ba Lead µg/L 2.0 3.0 6.0 13.0 6.5 9.5 6.0 4.0 y

(1.0 - 6.0) (2.0 - 10.0) (3.0 - 11.0) (3.0 - 120.0) (3.0 - 23.0) (2.0 - 16.0) (3.0 - 51.0) (2.0 - 8.0) Water Control Zone Zinc µg/L 50 40 125 60 80 240 255 20 (30 - 200) (20 - 50) (40 - 250) (40 - 100) (50 - 280) (40 - 610) (50 - 3,600) (10 - 40) Flow L/s 144 228 750 335 558 808 NM 43 (39 - 351) (45 - 672) (446 - 1,700) (182 - 672) (324 - 2,208) (126 - 1,920) (13 - 1,098)

6 -18 5. SP - soluble and particulate fractions i.e. total value. 6. Values at or below laboratory reporting limits are presented as laboratory reporting limits (see Table II). 7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. Cha 河 Table 6.3C Summary of water quality monitoring data for Fairview Park Nullah and minor streams in the Deep Bay Water Control Zone in 2002 Sampling Station River WaterQualit p

Parameter Unit Fairview Park Nullah Ha Pak Nai Stream Tai Shui Hang Stream Pak Nai Stream Dee Sheung Pak Nai Stream Ngau Hom Sha Stream Tsang Kok Stream ter 6 FVR1 DB1 DB2 DB3 DB5 DB6 DB8 Dissolved oxygen mg/L 5.3 9.0 8.2 8.0 8.5 9.0 8.7 (3.1 - 14.7) (7.5 - 10.3) (4.7 - 10.2) (6.6 - 9.8) (7.1 - 9.8) (3.7 - 10.9) (7.3 - 10.2) pH 7.4 7.5 7.5 7.0 7.2 7.4 7.8 (6.8 - 8.7) (7.3 - 7.8) (7.0 - 7.7) (6.9 - 7.5) (7.0 - 7.9) (6.9 - 8.1) (7.6 - 8.0) Suspended solids mg/L 49 2 6 4 5 11 5 (21 - 180) (1 - 4) (1 - 59) (2 - 23) (2 - 23) (3 - 81) (1 - 44) 5-day Biochemical Oxygen Demand mg/L 12 1 1 1 1 4 1 y (6 - 40) (1 - 4) (1 - 4) (1 - 2) (1 - 2) (1 - 33) (1 - 2) inHon Chemical Oxygen Demand mg/L 29 2 2 2 2 10 2 (20 - 46) (2 - 13) (2 - 12) (2 - 9) (2 - 6) (2 - 120) (2 - 8) Oil & grease mg/L 0.5 0.5 0.5 0.5 0.5 0.5 0.5 g (0.5 - 1.8) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 2.5) (0.5 - 0.5) Kon Faecal coliforms cfu/100mL 240,000 210 430 6,200 1,200 18,000 1,200 (51,000 - 2,000,000) (2 - 1,500) (20 - 3,100) (1,100 - 52,000) (180 - 21,000) (3,700 - 200,000) (60 - 19,000) g E. coli cfu/100mL 29,000 11 37 610 120 11,000 34 in 2002 (6,400 - 140,000) (1 - 120) (6 - 380) (100 - 14,000) (46 - 500) (2,100 - 200,000) (6 - 130) Ammonia-nitrogen mg/L 5.80 0.01 0.03 0.02 0.01 4.60 0.02 (2.50 - 14.00) (0.01 - 0.03) (0.01 - 0.07) (0.01 - 0.18) (0.01 - 0.04) (0.36 - 82.00) (0.01 - 0.11) Nitrate-nitrogen mg/L 0.98 0.12 0.11 0.28 0.17 0.57 0.17 (0.54 - 2.20) (0.06 - 0.35) (0.05 - 0.20) (0.01 - 0.80) (0.07 - 0.26) (0.01 - 1.00) (0.10 - 0.45) Total Kjeldahl nitrogen, SP mg/L 8.15 0.05 0.07 0.11 0.05 5.30 0.10 (3.90 - 14.00) (0.05 - 0.06) (0.05 - 0.32) (0.05 - 0.58) (0.05 - 0.28) (0.51 - 87.00) (0.05 - 0.26) Ortho-phosphate mg/L 0.90 0.01 0.01 0.03 0.01 0.85 0.01 (0.26 - 2.60) (0.01 - 0.02) (0.01 - 0.02) (0.02 - 0.07) (0.01 - 0.02) (0.11 - 5.70) (0.01 - 0.03) Total phosphorus, SP mg/L 1.40 0.02 0.02 0.05 0.02 1.25 0.02 (0.62 - 2.90) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.11) (0.02 - 0.02) (0.13 - 6.40) (0.02 - 0.07) Sulphide, SP mg/L 0.02 0.02 0.02 0.02 0.02 0.02 0.02 (0.02 - 0.04) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.22) (0.02 - 0.02) Aluminium µg/L 290 130 120 60 55 135 75 (200 - 720) (50 - 250) (50 - 220) (50 - 190) (50 - 160) (50 - 300) (50 - 240) Cadmium µg/L 0.10 0.10 0.10 0.10 0.10 0.20 0.10 (0.10 - 0.30) (0.10 - 0.10) (0.10 - 0.40) (0.10 - 0.10) (0.10 - 0.70) (0.10 - 1.40) (0.10 - 0.10) Chromium µg/L 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (1.0 - 3.0) (1.0 - 1.0) (1.0 - 3.0) (1.0 - 2.0) (1.0 - 1.0) (1.0 - 3.0) (1.0 - 1.0)

Copper µg/L 6.0 1.0 2.0 1.0 2.0 13.5 1.0 p (4.0 - 15.0) (1.0 - 14.0) (1.0 - 7.0) (1.0 - 7.0) (1.0 - 5.0) (2.0 - 84.0) (1.0 - 5.0) Ba Lead µg/L 5.5 1.0 3.0 1.0 1.0 4.0 2.0 y

(2.0 - 19.0) (1.0 - 2.0) (1.0 - 8.0) (1.0 - 3.0) (1.0 - 3.0) (2.0 - 14.0) (1.0 - 3.0) Water Control Zone Zinc µg/L 35 10 10 10 10 50 20 (20 - 100) (10 - 50) (10 - 50) (10 - 30) (10 - 50) (10 - 240) (10 - 160) Flow L/s NM 21 28 17 18 13 NM (2 - 183) (3 - 272) (3 - 175) (8 - 86) (1 - 36)

6 -19 5. SP - soluble and particulate fractions i.e. total value. 6. Values at or below laboratory reporting limits are presented as laboratory reporting limits (see Table II). 7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. Chapter 6 河 River WaterQuality in Hong Kong in 2002 N Shenzhen River Ganges Kan Tau Wai Wo Keng Shan

Man Ta Kwu Ling Kam To Lo Wu Loi Tung Sheung Shui Ping Che Ma Ho Sheung Tin Ping Mei Ha Heung Shek Shan Wu Hui Kwan Tei Kwu Tung Tsung Deep Bay Pak Long Fanling Lau Shui Heung Hok Tong Kung Tau Wai Leng River Indus River Beas

IN1 IN2 IN3 3 3 3 Excellent Excellent Excellent Zone Control Deep BayWater

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

12 Bad 12 Bad 12 Bad Water QualityWater Index Water QualityWater Index Very Bad QualityWater Index Very Bad Very Bad 15 15 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year Year 20 6 - Figure 6.1 Water Quality Index (WQI) of the River Indus and its tributaries Chapter 6 河 River Water QualityWater inHongRiver Kongin2002

N Shenzhen River Ganges

Kan Tau Wai Wo Keng Shan

Man Ta Kwu Ling Kam To Lo Wu Loi Tung Sheung Shui Ping Che Ma Ho Sheung Tin Ping Mei Ha Heung Shek Shan Wu Hui Kwan Tei Tsung Kwu Tung Pak Long Deep Bay Fanling Lau Shui Heung Hok Tong Kung Tau Wai Leng River Indus River Beas

RB3 RB2 RB1 3 3 3 Excellent Excellent Excellent Zone Control Deep BayWater

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

12 Bad 12 Bad 12 Bad Water QualityWater Index Water QualityWater Index Very Bad QualityWater Index Very Bad Very Bad 15 15 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year Year 21 6 - Figure 6.2 Water Quality Index (WQI) of the River Beas and its tributaries Chapter 6 河 River Water QualityWater inHongRiver Kongin2002 Shenzhen N River Ganges Kan Tau Wai Wo Keng Shan

Man Ta Kwu Ling Kam To Lo Wu Loi Tung Sheung Shui Ping Che Ma Ho Sheung Tin Ping Mei Ha Heung Shek Shan Wu Hui Kwan Tei Tsung Kwu Tung Pak Long Fanling Lau Shui Deep Bay Heung Hok Tong Kung Tau Wai Leng River Indus

River Beas

GR1 GR2 GR3 3 3 3 Excellent Excellent Excellent Zone Control Deep BayWater

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

River Water QualityWater inHongRiver Kongin2002 YL4 KT2 3 3 Excellent Excellent

6 Good 6 Good Deep Bay 9 Fair N 9 Fair 12 Bad 12 Bad

Water QualityWater Index Very Bad QualityWater Index Very Bad 15 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Nam Sang Wai Year Long Ping Year Estate Kam Tin Yuen Long YL3 Yuen Long Shui Tau 3 Excellent Kau Hui Ma Tin Pat Heung Ho Hok 6 Good Tsuen Tai Kei Shan Leng Ng Ka Shek Kong Tsuen Camp 9 Fair

Shap Pat 12 Bad Kam Tin River Heung

Water QualityWater Index Very Bad 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Yuen Long Creek

YL1 YL2 KT1 Zone Control Deep BayWater 3 3 3 Excellent Excellent Excellent

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

12 Bad 12 Bad 12 Bad Water QualityWater Index Water QualityWater Index Very Bad QualityWater Index Very Bad Very Bad 15 15 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year Year 23 6 - Figure 6.4 Water Quality Index (WQI) of Yuen Long Creek and Kam Tin River and their tributaries Chapter 6 河 River Water QualityWater inHongRiver Kongin2002 TSR1 3 Excellent Mai Po Nature Reserve Royal Palms 6 Good N Deep Bay Wo Shing Wai

9 Fair Palm Springs Lut Chau Fairview Park 12 Bad Fairview

Water QualityWater Index Park Very Bad Tin Shui Wai Nullah 15 Nullah 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Tai Sang Wai

FVR1 Nam Sang Wai 3 Excellent Yuen Long 6 Good Shek Po Tsuen 9 Fair Hung Shui 12 Bad Kiu

Water QualityWater Index Very Bad Wo Ping San 15 Tsuen 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 TSR2 Year 3 Excellent Tan Kwai Zone Control Deep BayWater 6 Good Tsuen

9 Fair Yuen Long Creek 12 Bad

Water QualityWater Index Very Bad 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year 24 6 - Figure 6.5 Water Quality Index (WQI) of Tin Shui Wai Nullah and Fairview Park Nullah and their tributaries Chapter 6 河 River Water QualityWater inHongRiver Kongin2002

Ngau Hom Deep Bay Sha Stream N Sheung Pak Nai Stream Pak Nai Stream

Ha Pak Nai Yuen Tau Shan Stream

Tai Shui Tsang Kok Hang Stream Stream

Po Lor Shan

Castle Peak

DB8 DB2 DB1 Zone Control Deep BayWater 3 3 3 Excellent Excellent Excellent

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

12 Bad 12 Bad 12 Bad Water QualityWater Index Water QualityWater Index Very Bad QualityWater Index Very Bad Very Bad 15 15 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year Year 25 6 - Figure 6.6 Water Quality Index (WQI) of minor streams in the Deep Bay Water Control Zone Chapter 6 河 River Water QualityWater inHongRiver Kongin2002

Ngau Hom Deep Bay Sha Stream N Sheung Pak Nai Stream Pak Nai Stream

Ha Pak Nai Yuen Tau Shan Stream

Tai Shui Tsang Kok Hang Stream Stream

Po Lor Shan

Castle Peak

DB3 DB5 DB6 Zone Control Deep BayWater 3 3 3 Excellent Excellent Excellent

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

12 Bad 12 Bad 12 Bad Water QualityWater Index Water QualityWater Index Very Bad QualityWater Index Very Bad Very Bad 15 15 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Year Year 26 6 - Figure 6.7 Water Quality Index (WQI) of minor streams in the Deep Bay Water Control Zone (continued) Chapter 7 North Western Water Control Zone to 83% in 2002. The Water Quality Index (WQI) of the Tuen Mun River stations has 7. North Western also been upgraded to “good” except for the Water Control Zone upstream station TN1 which remained as “bad” in 2002 (Figure 7.1).

7.1 Tuen Mun River 7.1.4 Due to pollution from unsewered villages in the northern and central parts of Tuen Mun, the E. coli bacterial levels in 2002 remained very high, ranging from 14,000 cfu/100mL to 620,000 cfu/100mL at various river stations (Table 7.3).

7.1.5 To tackle pollution problems in the Tuen Mun River catchment, the Government has planned to construct public sewer for some 16 villages between 2005 and 2009 under the Tuen Mun Sewerage Master Plan (SMP). However, the sewerage programme suffers slippage due to strong opposition from 7.1.1 The 38 km long Tuen Mun River local residents. Liaison with villagers has a catchment area of 16.5 km2. It passes continues to resolve objections. through Lam Tei, San Hing Tsuen, and Fu Tei before reaching Tuen Mun as an open nullah. 7.1.6 A review of the Tuen Mun SMP has been completed and plans for upgrading 7.1.2 The enforcement effort in the last sewerage works are being developed. After decade has removed a significant amount of the Tuen Mun sewerage works are constructed, organic pollutants in Tuen Mun River there should be further improvement of the resulting in improving trends in many water quality of Tuen Mun River. parameters (Tables 7.1 and 7.2). The Water E. coli level in Tuen Mun River (TN6) Quality Objective (WQO) compliance of the 1,000,000 river has more than doubled from 32% in

1988 to 78% in 2002. 100,000

WQO compliance of Tuen Mun River (cfu/100mL) 10,000

E. coli Tuen Mun River 1,000

WQO % Compliance 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year 1988 2001 2002 pH 100 100 99 Suspended solids 50 17 83 Improving trend of COD in Dissolved oxygen 7 83 86 Tuen Mun River (TN4) 300 COD 2 77 73 BOD 3 46 50 5 200 Overall 32 64 78 (mg/L)

100 7.1.3 Due to the reduction of construction COD activities in the river catchment, the 0 compliance with the suspended solid WQO has increased substantially from 17% in 2001 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

河 River Water Quality in Hong Kong in 2002 7 - 1 Chapter 7 North Western Water Control Zone

7.2 Tung Chung River WQO compliance of Tung Chung River

Tung Chung River

WQO % Compliance 1994 2001 2002 pH 94 97 89 Suspended solids 67 100 100 Dissolved oxygen 100 100 100 COD 94 100 97 BOD5 100 97 94 Overall 91 99 96

7.2.4 Tung Chung has undergone rapid development in recent years. Roads and other infrastructures were being built in areas 7.2.1 Tung Chung River has 3 main upstream of the western branch (station TC2) branches: the eastern branch runs through in 2002. The development will be extended to Wong Lung Hang while the two western the area upstream of the station TC1 in the branches pass through Shek Lau Po before near future. To guard against the possible entering Tung Chung Wan. adverse impact of increasing construction activities on the river water quality, EPD is 7.2.2 Since the declaration of the North highly vigilant in preventing polluted water Western Water Control Zone in 1992, from construction sites entering Tung Chung significant decreases in nutrients and organic River. pollutants in Tung Chung River have been detected.

Improving trend of COD in Tung Chung River (TC1) 25

15 (mg/L)

COD 5

1995 1996 1997 1998 1999 2000 2001 2002 Year

7.2.3 In 2002, the river has achieved a 96% compliance with the WQOs with “excellent” WQI and low E. coli levels (Table 7.3 and Figure 7.2).

河 River Water Quality in Hong Kong in 2002 7 - 2 Chapter 7 North Western Water Control Zone Table 7.1 River water quality trends in the North Western Water Control Zone based on the results of the Seasonal Kendall Test

Watercourse Tuen Mun River Tung Chung River Monitoring station TN1 TN2 TN3 TN4 TN5 TN6 TC1 TC2 TC3 Monitoring period* 82-02 82-02 82-02 82-02 85-02 82-02 93-02 93-02 93-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L − − − pH − − − Suspended solids mg/L − − − −

BOD5 mg/L − − − COD mg/L − Oil & grease mg/L − − − − − − E. coli cfu/100mL − − Faecal coliforms cfu/100mL − − Ammonia-nitrogen mg/L Nitrate-nitrogen mg/L − − − − Total Kjeldahl mg/L nitrogen (SP) − Ortho-phosphate mg/L − Total phosphorus mg/L (SP) − Sulphide (SP) mg/L − − − − − − − Aluminium µg/L − − − − Cadmium µg/L − − − − − − − − Chromium µg/L − − − Copper µg/L − − − Lead µg/L − − − − − − Zinc µg/L − − − − − − − − Flow L/s × × × × − − ×

河 River Water Quality in Hong Kong in 2002 7 - 3 Chapter 7 North Western Water Control Zone Table 7.2 Pollution load reduction in the Tuen Mun River catchment of the North Western Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1992 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic N.A.(5) 756 487 269 36 Industrial 4 3,970 1 3,969 99 (1) Commercial 12 2,371 8 2,363 99 WPCO Institutional 3 21 3 18 86 Tuen Mun Sub-total 19 7,118 499 6,619 93 River WDO(2) Livestock 0 9,520 0 9,520 100

Total 19 16,638 499 16,139 97

河 River Water Quality in Hong Kong in 2002 7 - 4 Chapter 7 North Western Water Control Zon Control Water Western North 7 Chapter 河 Table 7.3 Summary of water quality monitoring data for Tuen Mun River and Tung Chung River in 2002 Sampling Station River Water Quality in Hong Kong in 2002 Parameter Unit Tuen Mun River Tung Chung River TN1 TN2 TN3 TN4 TN5 TN6 TC1 TC2 TC3 Dissolved oxygen mg/L 4.5 8.9 5.3 7.1 5.9 5.3 7.3 8.2 8.5 (3.3 - 7.1) (7.7 - 11.3) (3.6 - 6.1) (3.8 - 9.3) (3.1 - 8.1) (4.5 - 7.4) (4.8 - 8.7) (7.5 - 9.4) (7.5 - 10.7) pH 7.8 7.3 7.9 8.1 7.9 7.5 7.1 8.1 8.2 (7.5 - 8.2) (6.8 - 9.2) (7.4 - 8.0) (7.3 - 8.4) (7.4 - 8.3) (6.9 - 8.2) (6.4 - 7.9) (7.0 - 9.1) (7.6 - 9.0) Suspended solids mg/L 38 11 18 13 24 5 1 2 5 (9 - 240) (6 - 42) (4 - 750) (3 - 180) (5 - 1,500) (2 - 38) (1 - 7) (1 - 49) (1 - 180) 5-day Biochemical Oxygen Demand mg/L 4224464111 (12 - 160) (1 - 9) (2 - 43) (2 - 9) (1 - 20) (1 - 20) (1 - 1) (1 - 1) (1 - 6) Chemical Oxygen Demand mg/L 63917141613335 (22 - 400) (2 - 20) (10 - 36) (5 - 25) (7 - 73) (6 - 29) (2 - 7) (2 - 5) (2 - 33) Oil & grease mg/L 3.1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 (0.5 - 13.0) (0.5 - 1.1) (0.5 - 3.1) (0.5 - 1.5) (0.5 - 3.6) (0.5 - 0.6) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 0.5) Faecal coliforms cfu/100mL 2,100,000 54,000 450,000 120,000 220,000 140,000 1,400 1,300 3,700 (950,000 - 5,400,000) (9,800 - 190,000) (81,000 - 2,300,000) (8,000 - 1,900,000) (76,000 - 2,000,000) (12,000 - 1,400,000) (99 - 13,000) (120 - 18,000) (1 - 120,000) E. coli cfu/100mL 620,000 14,000 67,000 24,000 49,000 15,000 260 120 650 (170,000 - 1,600,000) (4,000 - 76,000) (3,500 - 840,000) (3,800 - 280,000) (13,000 - 240,000) (510 - 170,000) (15 - 13,000) (13 - 12,000) (1 - 46,000) Ammonia-nitrogen mg/L 9.45 0.36 0.58 0.47 0.58 0.56 0.01 0.01 0.40 (2.40 - 15.00) (0.04 - 1.80) (0.22 - 2.30) (0.17 - 0.93) (0.26 - 1.60) (0.23 - 1.40) (0.01 - 0.14) (0.01 - 0.05) (0.01 - 1.20) Nitrate-nitrogen mg/L 0.18 1.55 0.49 0.54 0.59 0.42 0.05 0.01 0.11 (0.01 - 3.30) (0.64 - 2.80) (0.26 - 0.77) (0.35 - 0.72) (0.10 - 0.94) (0.12 - 0.75) (0.01 - 0.13) (0.01 - 0.13) (0.02 - 3.40) Total Kjeldahl nitrogen, SP mg/L 12.50 0.65 1.25 0.93 1.50 1.01 0.12 0.12 0.65 (3.50 - 37.00) (0.09 - 1.90) (0.66 - 5.00) (0.41 - 1.40) (0.67 - 5.20) (0.50 - 2.60) (0.05 - 0.38) (0.05 - 0.29) (0.05 - 3.10) Ortho-phosphate mg/L 1.55 0.20 0.04 0.07 0.06 0.06 0.01 0.01 0.06 (0.53 - 2.40) (0.04 - 1.40) (0.02 - 0.12) (0.01 - 0.20) (0.01 - 0.16) (0.01 - 0.17) (0.01 - 0.02) (0.01 - 0.02) (0.01 - 0.25) Total phosphorus, SP mg/L 2.05 0.30 0.18 0.18 0.29 0.12 0.02 0.02 0.08 (0.86 - 5.20) (0.05 - 1.60) (0.08 - 1.80) (0.07 - 0.45) (0.07 - 3.40) (0.08 - 0.32) (0.02 - 0.05) (0.02 - 0.02) (0.02 - 0.50) Sulphide, SP mg/L 0.09 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 (0.02 - 0.52) (0.02 - 0.07) (0.02 - 0.07) (0.02 - 0.02) (0.02 - 1.00) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) Aluminium µg/L 305 265 375 430 650 170 50 50 75 (120 - 570) (80 - 580) (140 - 24,000) (120 - 4,200) (110 - 37,000) (100 - 710) (50 - 70) (50 - 140) (50 - 2,100) Cadmium µg/L 0.10 0.10 0.15 0.10 0.10 0.10 0.10 0.10 0.10 (0.10 - 0.20) (0.10 - 0.30) (0.10 - 0.70) (0.10 - 0.30) (0.10 - 0.80) (0.10 - 0.20) (0.10 - 0.20) (0.10 - 0.20) (0.10 - 0.80) Chromium µg/L 1.0 1.0 5.0 4.0 4.5 3.0 1.0 1.0 1.0 (1.0 - 4.0) (1.0 - 1.0) (2.0 - 28.0) (1.0 - 9.0) (2.0 - 43.0) (1.0 - 10.0) (1.0 - 2.0) (1.0 - 1.0) (1.0 - 9.0) Copper µg/L 7.0 2.0 7.0 6.5 7.0 7.0 1.0 1.0 2.5 (3.0 - 20.0) (1.0 - 7.0) (3.0 - 24.0) (2.0 - 21.0) (3.0 - 31.0) (3.0 - 11.0) (1.0 - 5.0) (1.0 - 6.0) (1.0 - 38.0) Lead µg/L 6.5 5.5 3.5 7.0 15.0 2.0 1.0 1.0 1.5 (4.0 - 16.0) (2.0 - 12.0) (1.0 - 59.0) (1.0 - 35.0) (2.0 - 76.0) (1.0 - 8.0) (1.0 - 2.0) (1.0 - 4.0) (1.0 - 15.0) Zinc µg/L 60 40 40 30 40 30 10 10 55 (40 - 140) (20 - 170) (10 - 140) (10 - 80) (10 - 240) (20 - 40) (10 - 20) (10 - 30) (20 - 240) Flow L/s 101 47 NM NM NM NM 34 31 NM (38 - 243) (4 - 562) (7 - 905) (11 - 1,200)

7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. e Chapter 7 河

River Water QualityWater inHongRiver Kongin2002 TN1 TN2 3 3 Excellent Excellent

6 Good N Lam Tei 6 Good

9 Fair 9 Fair To Yuen Wai

12 Bad 12 Bad Siu Hong Court Water QualityWater Index Very Bad QualityWater Index Very Bad 15 Fu Tei 15 Lingnan Tuen Mun Hospital 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 University Year Year Chelsea Heights Tuen Mun Ho Tin LRT San Hui TN4 3 San Fat Estate Excellent Tuen Mun

6 Good Yau Oi Estate Tuen Mun River 9 Fair

12 Bad

Water QualityWater Index Very Bad 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Castle Peak Bay Zone Control Water Western North

TN5 TN3 TN6 3 3 3 Excellent Excellent Excellent

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

Tung Chung Wan N

Ma Wan Chung Tung Chung River Shan Ha

San Tung Chung Hung Ngau Au Ling Pe

Nim Yuen Shek Lau Wong Lung Hang Po

Shek Sze Shan Shek Mun Tung Chung Kap North Western Water Control Zone Control Water Western North

TC1 TC2 TC3 3 3 3 Excellent Excellent Excellent

6 Good 6 Good 6 Good

9 Fair 9 Fair 9 Fair

8.1.3 In 2002, the overall compliance with 8. Western Buffer the key Water Quality Objectives (WQOs) Water Control Zone was high at 97% with “excellent” and “good” Water Quality Indices (WQIs) (Figure 8.1). However, due to the unsewered villages 8.1 Pai Min Kok (Anglers’) Stream nearby, the E. coli levels in the stream were high (Table 8.3) and the grading of the downstream Anglers’ Beach remained as “very poor” in 2002.

WQO compliance of Pai Min Kok (Anglers’) Stream

Pai Min Kok (Anglers’) Stream

WQO % Compliance 1988 2001 2002 pH 100 100 100 Suspended solids 50 100 100 Dissolved oxygen 30 100 100 COD 50 100 100 BOD5 0 96 83 Overall 46 99 97

E. coli level in Pai Min Kok (Anglers') Stream (AN1) 100,000

8.1.1 The Pai Min Kok (Anglers’) Stream 10,000 runs through Pai Min Kok Village before flowing onto Anglers’ Beach near Sham (cfu/100mL) 1,000 Tseng. E. coli 100 8.1.2 Since the declaration of the Western Buffer Water Control Zone and the 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year implementation of the Livestock Waste Control Scheme in the early 90s, 96% of the 8.1.4 To tackle the bacterial pollution point source pollution load from Pai Min Kok problem in the Pai Min Kok Stream, public Stream has been eliminated and upward trends sewer are currently being constructed under were shown in many of the water quality the Ting Kau and Sham Tseng Sewerage parameters (Tables 8.1 and 8.2). Scheme to collect sewage from the

Improving trend of DO in developments along the coastal strip between Pai Min Kok (Anglers') Stream (AN2) Tsing Lung Tau and Ting Kau. The sewage 12 collected will be conveyed to the Sham Tseng

10 Sewage Treatment Plant, which is scheduled to start operation in 2004. The sewage will be 8 treated by chemically enhanced primary (mg/L)

6 treatment with disinfection prior to discharge. DO The sewage generated by some developments 4 along the Castle Peak Road would then be

2 conveyed to and treated properly at the plant.

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

河 River Water Quality in Hong Kong in 2002 8 - 1 Chapter 8 Western Buffer Water Control Zone Table 8.1 River water quality trends in the Western Buffer Water Control Zone based on the results of the Seasonal Kendall Test

Watercourse Pai Min Kok (Anglers’) Stream Monitoring station AN1 AN2 Monitoring period* 88-02 88-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L pH − Suspended solids mg/L −

BOD5 mg/L COD mg/L − Oil & grease mg/L − − E. coli cfu/100mL − − Faecal coliforms cfu/100mL − − Ammonia-nitrogen mg/L − Nitrate-nitrogen mg/L Total Kjeldahl mg/L nitrogen (SP) Ortho-phosphate mg/L Total phosphorus mg/L (SP) Sulphide (SP) mg/L − − Aluminium µg/L − − Cadmium µg/L − − Chromium µg/L − − Copper µg/L − − Lead µg/L Zinc µg/L − Flow L/s × −

河 River Water Quality in Hong Kong in 2002 8 - 2 Chapter 8 Western Buffer Water Control Zone Table 8.2 Pollution load reduction in the Pai Min Kok (Anglers’) Stream catchment of the Western Buffer Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1993 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic 32 4.6 0.2 4.4 96 Industrial N.A.(5) N.A. N.A. N.A. N.A. (1) Commercial N.A. N.A. N.A. N.A. N.A. WPCO Institutional N.A. N.A. N.A. N.A. N.A. Pai Min Kok (Anglers’) Sub-total 32 4.6 0.2 4.4 96 Stream WDO(2) Livestock N.A.

Total 32 4.6 0.2 4.4 96

河 River Water Quality in Hong Kong in 2002 8 - 3 Chapter 8 Western Buffer Water Control Zon Control Water Buffer Western 8 Chapter 河 Table 8.3 Summary of water quality monitoring data for Pai Min Kok (Anglers') Stream in 2002 Sampling Station River Water Quality in Hong Kong in 2002 Parameter Unit Pai Min Kok (Anglers') Stream AN1 AN2 Dissolved oxygen mg/L 7.4 9.0 (5.8 - 9.5) (7.7 - 10.9) pH 7.6 8.0 (6.9 - 8.6) (7.3 - 9.0) Suspended solids mg/L 6 4 (2 - 300) (1 - 130) 5-day Biochemical Oxygen Demand mg/L 3 2 (2 - 11) (1 - 24) Chemical Oxygen Demand mg/L 15 9 (6 - 28) (3 - 19) Oil & grease mg/L 0.5 0.5 (0.5 - 0.7) (0.5 - 0.7) Faecal coliforms cfu/100mL 87,000 37,000 (11,000 - 1,100,000) (8,500 - 140,000) E. coli cfu/100mL 17,000 8,000 (4,100 - 90,000) (800 - 110,000) Ammonia-nitrogen mg/L 0.40 0.21 (0.06 - 1.30) (0.02 - 0.56) Nitrate-nitrogen mg/L 1.60 1.27 (0.36 - 4.60) (0.33 - 5.60) Total Kjeldahl nitrogen, SP mg/L 0.78 0.48 (0.24 - 2.70) (0.20 - 1.30) Ortho-phosphate mg/L 0.19 0.13 (0.05 - 0.50) (0.05 - 0.99) Total phosphorus, SP mg/L 0.32 0.20 (0.09 - 1.40) (0.07 - 1.20) Sulphide, SP mg/L 0.02 0.02 (0.02 - 0.02) (0.02 - 0.02) Aluminium µg/L 120 85 (50 - 1,000) (50 - 650) Cadmium µg/L 0.10 0.10 (0.10 - 0.20) (0.10 - 0.10) Chromium µg/L 1.0 1.0 (1.0 - 3.0) (1.0 - 1.0) Copper µg/L 7.0 3.5 (4.0 - 13.0) (2.0 - 14.0) Lead µg/L 2.5 1.0 (1.0 - 16.0) (1.0 - 9.0) Zinc µg/L 50 20 (20 - 120) (20 - 80) Flow L/s NM 7 (1 - 24)

7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. e Chapter 8 河 River Water QualityWater inHongRiver Kongin2002

N Pai Min Kok Stream (Anglers’ Stream)

AN2 3 Excellent

6 Good

9 Fair

12 Bad

Water QualityWater Index Very Bad 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Pai Min Year AN1 Kok 3 Village Excellent Sea Crest Villa

6 Good Western Buffer Water Control Zone Control Water Buffer Western

9 Fair Tsing Lung Tau 12 Bad

Water QualityWater Index Very Bad 15 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Anglers’ Beach 5 8 - Figure 8.1 Water Quality Index (WQI) of Pai Min Kok (Anglers’) Stream and its tributaries Chapter 9 Victoria Harbour Water Control Zone

9.1.3 Similar to 2001, the Sam Dip Tam 9. Victoria Stream has achieved a high compliance with the key Water Quality Objectives (WQO) in Harbour 2002. The downstream station sustained its “excellent” Water Quality Index (WQI); while Water Control Zone the middle reach of Sam Dip Tam has slightly slipped to “good” (Figure 9.1). Due to the unsewered villages in the catchment, the 9.1 Sam Dip Tam Stream E.coli levels were still high (Table 9.3A). Enforcement of pollution control will be continued to further reduce the pollution load in the stream (Table 9.2).

WQO compliance of Sam Dip Tam Stream

Sam Dip Tam Stream

WQO % Compliance 1994 2001 2002 pH 100 100 100 Suspended solids 67 100 100 Dissolved oxygen 92 100 100 COD 72 94 100 BOD5 31 94 80 Overall 72 98 96

9.2 Kau Wa Keng Stream

9.1.1 With a catchment area of 4.5 km2, the 12 km Sam Dip Tam Stream runs through Tsuen Wan and drains into Rambler Channel through an underground box culvert.

9.1.2 Since the implementation of legislative control in the early 90s, there has been a significant improvement in the dissolved oxygen (DO) and nutrient parameters in the stream (Table 9.1A).

Improving trend of DO in Sam Dip Tam Stream (TW3) 10

9.2.1 The Kau Wa Keng Stream runs 9 through Kau Wa Keng San Tsuen as an open

8 (mg/L) culvert and drains into the inshore water near

DO Lai Chi Kok.

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

河 River Water Quality in Hong Kong in 2002 9 - 1 Chapter 9 Victoria Harbour Water Control Zone

9.2.2 Since the declaration of the Victoria 9.3 Kai Tak Nullah Harbour Water Control Zone (Phase I) in 1994, 81% of the point source pollution load has been removed (Table 9.2) resulting in a significant improvement in DO and other water quality parameters (Table 9.1A). As in 2001, it maintained a high compliance with the key WQOs with a “good” WQI in 2002 (Figure 9.2).

Improving trend of DO in Kau Wa Keng Stream (KW3) 12

8 9.3.1 Kai Tak Nullah is a major storm

(mg/L) water channel in the South-East Kowloon. Its

DO 4 catchment includes urban districts such as San Po Kong, Diamond Hill, Tsz Wan Shan, Wong Tai Sin, Wang Tau Hom, Lok Fu and Kowloon 0 City. 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year 9.3.2 Since the enforcement of water pollution legislation and the implementation WQO compliance of Kau Wa Keng Stream of the Tolo Harbour Effluent Export Scheme (THEES) in the 90s, Kai Tak Nullah has Kau Wa Keng Stream shown a marked reduction in organic and WQO % Compliance other pollutants (Table 9.1B). In 2002, the nullah maintained its “fair” to “bad” WQI like 1994 2001 2002 pH 100 100 100 that in the previous year (Figure 9.3). Suspended solids 100 100 100 Dissolved oxygen 75 100 100 COD 58 100 100 Improving trend of BOD5 in

BOD5 42 83 67 Kai Tak Nullah (KN4) 160 Overall 75 97 93

120 9.2.3 Despite the substantial reduction in (mg/L) 80 pollution and improvement in water quality, 5

the E.coli bacterial levels in the stream BOD 40 remained high (Table 9.3A) due to unsewered village houses in the catchment. Enforcement 0 of pollution control will be continued to 1994 1995 1996 1997 1998 1999 2000 2001 2002 improve the stream water quality. Year

河 River Water Quality in Hong Kong in 2002 9 - 2 Chapter 9 Victoria Harbour Water Control Zone

E. coli level in Kai Tak Nullah (KN4) 10,000,000

1,000,000

(cfu/100mL) 100,000

E. coli 10,000 1995 1996 1997 1998 1999 2000 2001 2002 Year

9.3.3 To further improve the water quality of the effluent from THEES, the Sha Tin STW Stage III extension works will be implemented. Phases I and II of the works are expected to complete by 2004 and 2007 respectively. Enforcement efforts will also be continued to curb the discharge of pollutants into Kai Tak Nullah.

河 River Water Quality in Hong Kong in 2002 9 - 3 Chapter 9 Victoria Harbour Water Control Zone Table 9.1A River water quality trends in the Victoria Harbour Water Control Zone based on the results of the Seasonal Kendall Test

Kau Wa Keng Watercourse Sam Dip Tam Stream Stream Monitoring station TW1 TW2 TW3 KW3 Monitoring period* 84-02 84-02 85-02 87-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L pH Suspended solids mg/L − −

BOD5 mg/L − − COD mg/L − − Oil & grease mg/L − − − E. coli cfu/100mL − − − Faecal coliforms cfu/100mL − − − Ammonia-nitrogen mg/L − Nitrate-nitrogen mg/L − − − Total Kjeldahl mg/L nitrogen (SP) Ortho-phosphate mg/L Total phosphorus mg/L (SP) Sulphide (SP) mg/L − − − − Aluminium µg/L − − Cadmium µg/L − − − Chromium µg/L − − − − Copper µg/L − − − Lead µg/L − − Zinc µg/L − − − − Flow L/s − × −

河 River Water Quality in Hong Kong in 2002 9 - 4 Chapter 9 Victoria Harbour Water Control Zone Table 9.1B River water quality trends in the Victoria Harbour Water Control Zone based on the results of the Seasonal Kendall Test

Watercourse Kai Tak Nullah Monitoring station KN1 KN2 KN3 KN4 KN5 KN7 Monitoring period* 86-02 86-02 86-02 86-02 86-02 86-02 Parameter Unit Results of the Seasonal Kendall Test Dissolved oxygen mg/L − pH − − − − − Suspended solids mg/L

BOD5 mg/L COD mg/L Oil & grease mg/L − − − E. coli cfu/100mL − − − − − Faecal coliforms cfu/100mL − − − − − Ammonia-nitrogen mg/L − − − − − − Nitrate-nitrogen mg/L Total Kjeldahl mg/L nitrogen (SP) − Ortho-phosphate mg/L − − − − − − Total phosphorus mg/L (SP) − − Sulphide (SP) mg/L − − − − − − Aluminium µg/L − − − − − Cadmium µg/L − Chromium µg/L − Copper µg/L Lead µg/L Zinc µg/L − − Flow L/s × × × × × ×

河 River Water Quality in Hong Kong in 2002 9 - 5 Chapter 9 Victoria Harbour Water Control Zone Table 9.2 Pollution load reductions in the river catchments of the Victoria Harbour Water Control Zone as at the end of 2002

Pollution from point source discharges Pollution Pollution BOD load reduction Watercourse Control BOD load BOD load source (1995 – 2002) Ordinance No. of before after discharges(3) control(4) control(3) (kg/day) (kg/day) (kg/day) (%) Domestic 138 10 10 0 0 Industrial 2 12 0 12 100 (1) Commercial 1 9 9 0 0 WPCO Institutional 3 2 1 1 50 Sam Dip Tam Sub-total 144 33 20 13 39 Stream WDO(2) Livestock N.A.(5)

Total 144 33 20 13 39

Domestic 120 9 9 0 0 Industrial N.A. N.A. N.A. N.A. N.A. Commercial N.A. N.A. N.A. N.A. N.A. WPCO Institutional 1 39 0 39 100 Kau Wa Sub-total *121 *48 9 39 81 Keng Stream WDO Livestock N.A.

Total *121 *48 9 39 81

河 River Water Quality in Hong Kong in 2002 9 - 6 Cha 河 Table 9.3A Summary of water quality monitoring data for Sam Dip Tam Stream and Kau Wa Keng Stream in 2002 River WaterQualit p

Parameter Unit Sam Dip Tam Stream HarbourWaterControlZone Victoria Kau Wa Keng Stream ter 9 TW1 TW2 TW3 KW3 Dissolved oxygen mg/L 6.9 8.2 8.3 8.4 (4.0 - 8.6) (7.7 - 10.2) (7.8 - 10.2) (7.7 - 10.8) pH 7.3 7.9 7.5 7.5 (6.9 - 7.7) (7.0 - 8.2) (6.7 - 7.9) (6.9 - 7.8) Suspended solids mg/L 3255 (1 - 10) (1 - 7) (1 - 66) (2 - 14) 5-day Biochemical Oxygen Demand mg/L 4414 y (1 - 6) (2 - 17) (1 - 3) (2 - 15) inHon Chemical Oxygen Demand mg/L 9 9 5 12 (4 - 14) (4 - 18) (2 - 13) (9 - 22) Oil & grease mg/L 0.5 0.5 0.5 0.5 g (0.5 - 1.7) (0.5 - 0.9) (0.5 - 0.7) (0.5 - 0.8) Kon Faecal coliforms cfu/100mL 360,000 270,000 22,000 120,000 (160,000 - 750,000) (69,000 - 1,900,000) (3,200 - 170,000) (32,000 - 500,000) g E. coli cfu/100mL 15,000 94,000 8,700 56,000 in 2002 (2,200 - 110,000) (22,000 - 250,000) (1,000 - 85,000) (23,000 - 360,000) Ammonia-nitrogen mg/L 0.10 0.32 0.04 0.42 (0.01 - 0.23) (0.08 - 1.60) (0.01 - 0.21) (0.14 - 3.20) Nitrate-nitrogen mg/L 0.71 1.10 1.65 1.95 (0.15 - 1.50) (0.84 - 1.90) (0.85 - 2.70) (1.00 - 3.60) Total Kjeldahl nitrogen, SP mg/L 0.31 0.65 0.28 0.77 (0.18 - 0.64) (0.26 - 2.20) (0.10 - 0.60) (0.54 - 3.80) Ortho-phosphate mg/L 0.02 0.16 0.16 0.09 (0.01 - 0.07) (0.07 - 0.42) (0.08 - 0.23) (0.05 - 0.23) Total phosphorus, SP mg/L 0.08 0.22 0.18 0.23 (0.06 - 0.14) (0.10 - 0.49) (0.11 - 0.43) (0.09 - 0.52) Sulphide, SP mg/L 0.02 0.02 0.02 0.02 (0.02 - 0.04) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.02) Aluminium µg/L 50 55 70 120 (50 - 120) (50 - 420) (50 - 920) (60 - 310) Cadmium µg/L 0.10 0.10 0.10 1.10 (0.10 - 0.30) (0.10 - 0.10) (0.10 - 0.30) (0.60 - 1.60) Chromium µg/L 1.0 1.0 1.0 1.0 (1.0 - 1.0) (1.0 - 1.0) (1.0 - 1.0) (1.0 - 4.0) Copper µg/L 2.0 3.0 4.0 4.0 (2.0 - 7.0) (2.0 - 10.0) (2.0 - 41.0) (2.0 - 6.0) Lead µg/L 1.0 2.0 3.0 3.0 (1.0 - 2.0) (1.0 - 26.0) (1.0 - 52.0) (1.0 - 6.0) Zinc µg/L 30 30 20 110 (20 - 40) (10 - 40) (10 - 130) (60 - 160) Flow L/s 30 51 NM 22 (6 - 330) (12 - 120) (7 - 38)

Notes: 1. Data presented are in annual medians of monthly samples; except those for faecal coliforms andE. coli which are in annual geometric means. 2. Figures in brackets are annual ranges. 3. NM indicates no measurement taken. 4. cfu - colony forming unit. 5. SP - soluble and particulate fractions i.e. total value. 9 -7 6. Values at or below laboratory reporting limits are presented as laboratory reporting limits (see Table II). 7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. Cha 河 Table 9.3B Summary of water quality monitoring data for Kai Tak Nullah in 2002 Sampling Station River WaterQualit p

Parameter Unit Kai Tak Nullah HarbourWaterControlZone Victoria ter 9 KN1 KN2 KN3 KN4 KN5 KN7 Dissolved oxygen mg/L 5.2 7.3 7.3 7.3 7.8 7.0 (2.6 - 6.7) (6.4 - 8.2) (6.0 - 8.5) (3.5 - 9.4) (6.3 - 9.2) (5.3 - 8.0) pH 7.3 7.4 7.4 7.2 7.3 7.3 (7.1 - 7.5) (7.2 - 7.5) (7.3 - 7.6) (6.9 - 7.5) (6.9 - 7.7) (6.8 - 7.5) Suspended solids mg/L 4 9 15 20 15 12 (3 - 12) (5 - 13) (14 - 15) (9 - 100) (7 - 140) (7 - 130) 5-day Biochemical Oxygen Demand mg/L 10 28 15 13 11 12 y (5 - 29) (10 - 47) (15 - 15) (7 - 41) (6 - 30) (6 - 45) inHon Chemical Oxygen Demand mg/L 31 27 30 32 31 28 (21 - 41) (24 - 29) (28 - 32) (20 - 60) (20 - 44) (18 - 45) Oil & grease mg/L 0.5 0.5 0.5 0.5 0.5 0.5 g (0.5 - 1.3) (0.5 - 0.5) (0.5 - 0.5) (0.5 - 2.6) (0.5 - 0.9) (0.5 - 2.6) Kon Faecal coliforms cfu/100mL 1,500,000 600,000 520,000 470,000 160,000 190,000 (190,000 - 14,000,000) (490,000 - 740,000) (480,000 - 560,000) (92,000 - 31,000,000) (75,000 - 560,000) (47,000 - 7,200,000) g E. coli cfu/100mL 640,000 160,000 140,000 130,000 47,000 55,000 in 2002 (70,000 - 6,400,000) (80,000 - 310,000) (110,000 - 190,000) (30,000 - 3,500,000) (18,000 - 230,000) (12,000 - 1,400,000) Ammonia-nitrogen mg/L 7.10 9.00 9.35 2.60 2.20 2.10 (0.95 - 15.00) (3.00 - 15.00) (2.70 - 16.00) (0.16 - 15.00) (0.17 - 16.00) (0.12 - 17.00) Nitrate-nitrogen mg/L 1.85 1.65 1.60 2.25 2.75 2.75 (0.01 - 4.00) (1.30 - 2.00) (1.30 - 1.90) (0.01 - 5.90) (1.40 - 5.80) (1.10 - 5.40) Total Kjeldahl nitrogen, SP mg/L 8.90 10.85 9.95 4.70 4.05 3.70 (2.00 - 16.00) (3.70 - 18.00) (3.90 - 16.00) (1.70 - 18.00) (1.50 - 18.00) (1.40 - 18.00) Ortho-phosphate mg/L 1.25 1.01 0.90 0.92 0.88 0.88 (0.46 - 1.70) (0.82 - 1.20) (0.79 - 1.00) (0.45 - 1.70) (0.33 - 1.70) (0.23 - 1.60) Total phosphorus, SP mg/L 1.50 1.45 1.40 1.35 1.20 1.30 (0.75 - 2.10) (1.10 - 1.80) (1.20 - 1.60) (0.77 - 3.70) (0.56 - 4.50) (0.66 - 3.70) Sulphide, SP mg/L 0.18 0.02 0.02 0.02 0.02 0.02 (0.03 - 1.00) (0.02 - 0.02) (0.02 - 0.02) (0.02 - 0.09) (0.02 - 0.03) (0.02 - 0.05) Aluminium µg/L 75 70 70 100 80 75 (50 - 170) (50 - 90) (70 - 70) (60 - 540) (50 - 670) (50 - 540) Cadmium µg/L 0.10 0.10 0.10 0.10 0.10 0.10 (0.10 - 0.10) (0.10 - 0.10) (0.10 - 0.10) (0.10 - 0.20) (0.10 - 0.30) (0.10 - 0.20) Chromium µg/L 2.5 2.5 6.0 3.0 3.0 3.0 (1.0 - 4.0) (1.0 - 4.0) (1.0 - 11.0) (2.0 - 5.0) (1.0 - 5.0) (1.0 - 5.0) Copper µg/L 4.0 4.5 5.5 7.0 6.5 7.0 (3.0 - 7.0) (3.0 - 6.0) (4.0 - 7.0) (5.0 - 26.0) (4.0 - 35.0) (4.0 - 30.0) Lead µg/L 1.0 2.0 20.0 2.0 1.0 1.0 (1.0 - 1.0) (1.0 - 3.0) (1.0 - 39.0) (1.0 - 4.0) (1.0 - 3.0) (1.0 - 11.0) Zinc µg/L 30 70 35 40 30 35 (20 - 40) (30 - 110) (20 - 50) (30 - 60) (20 - 60) (20 - 180) Flow L/s NM NM NM NM NM NM

Notes: 1. Data presented are in annual medians of monthly samples; except those for faecal coliforms andE. coli which are in annual geometric means. 2. Figures in brackets are annual ranges. 3. NM indicates no measurement taken. 4. cfu - colony forming unit. 5. SP - soluble and particulate fractions i.e. total value. 9 -8 6. Values at or below laboratory reporting limits are presented as laboratory reporting limits (see Table II). 7. Equal values for annual medians (or geometric means) and ranges indicate that all data are the same as or below laboratory reporting limits. Chapter 9 河 River Water QualityWater inHongRiver Kongin2002 TW1 3 Sam Dip Tam Stream Excellent N 6 Good

9 Fair TW3 12 Bad 3 Excellent Water QualityWater Index Very Bad 15 6 Good 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year 9 Fair

12 Bad

Water QualityWater Index Very Bad TW2 15 3 Excellent 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year 6 Good

9 Fair

12 Bad Victoria Harbour Water Control Zone Control Water Harbour Victoria

Water QualityWater Index Very Bad 15 Western Monastery 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

San Tsuen Lo Wai

Sai Lau Kok Tsuen d Yi Pei Chun i Shan Roa Cheung Pe

Shek Wai Kok Estate 9 9 - Figure 9.1 Water Quality Index (WQI) of Sam Dip Tam Stream and its tributaries Chapter 9 河 River Water QualityWater inHongRiver Kongin2002

N Ha Kwai Chung

KauWaKengStream

KW3 3 Excellent

6 Good

9 Fair Kau Wa Keng Chung Shan 12 Bad San Tsuen Kau Wa Keng Terreace Water QualityWater Index Very Bad 15 Victoria Harbour Water Control Zone Control Water Harbour Victoria 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year

Lai King Hill Road

Princess Margaret Hospital Mei Foo 10 9 - Figure 9.2 Water Quality Index (WQI) of Kau Wa Keng Stream Chapter 9 河 Tsz Wan Shan Diamond Hill River Water QualityWater inHongRiver Kongin2002 KN7 KN5 3 3 Excellent N Excellent Wong 6 Good Tai 6 Good Sin 9 Fair 9 Fair San Po Kong

12 Bad 12 Bad

Water QualityWater Index Very Bad QualityWater Index Very Bad 15 15 Wang 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Tau Year Hom Year Kai Tak Nullah KN4 Lok Fu KN3 3 3 Excellent Excellent

6 Good Kowloon 6 Good City 9 Fair 9 Fair

12 Bad Ex-Hong Kong 12 Bad Water QualityWater Index Water QualityWater Index Very Bad International Airport Very Bad 15 (Kai Tak) 15 Victoria Harbour Water Control Zone Control Water Harbour Victoria 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Year Kowloon Bay Year

KN2 KN1 3 3 Excellent o Excellent ld

6 Good K 6 Good a i T a 9 Fair k 9 Fair A i 12 Bad rp 12 Bad o r Water QualityWater Index Water QualityWater Index t Very Bad R Very Bad 15 u 15 n 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 w a Year y Year 11 9 - Figure 9.3 Water Quality Index (WQI) of Kai Tak Nullah