River Water Quality in Hong Kong in 2017 Environmental Protection Department River WaterThe Quality Government in Hong Kong 2017 of the Hong Kong Special Administrative Region 1 Mission To conduct an effective and scientifically sound water monitoring programme that helps protect the health of Hong Kong’s rivers and streams and ensure the water quality objectives can be achieved and maintained. Tin Shui Wai Nullah 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. Copyright Notice 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 written permission of the Director of Environmental Protection. Acknowledgement We acknowledge the Government Laboratory for undertaking chemical analyses of the water samples. River Water Quality in Hong Kong 2017 2 Content 1. Introduction 2. An overview of Hong Kong’s rivers in 2017 3. Eastern New Territories rivers and streams 4. Northwestern New Territories rivers and streams 5. Lantau Island rivers and streams 6. Southwestern New Territories and Kowloon rivers and streams Appendices Appendix A Summary of river water quality monitoring stations and sampling A-1 frequencies in 2017 Appendix B River water quality parameters and methods used for their analysis B-1 B-2 Appendix C Key Water Quality Objectives (WQOs) for the river monitoring C-1 stations in the Eastern New Territories Key Water Quality Objectives (WQOs) for the river monitoring C-2 stations in the Northwestern New Territories Key Water Quality Objectives (WQOs) for the river monitoring C-3 stations on Lantau Island Key Water Quality Objectives (WQOs) for the river monitoring C-4 stations in the Southwestern New Territories and Kowloon Appendix D Water Control Zones in Hong Kong D-1 Appendix E Summary of water quality monitoring data for Shing Mun River E-1 (Main Channel and Siu Lek Yuen Nullah) in 2017 Summary of water quality monitoring data for Shing Mun River (Fo E-2 Tan Nullah and Kwun Yam Shan Stream) in 2017 Summary of water quality monitoring data for Shing Mun River (Tai E-3 Wai Nullah and Tin Sum Nullah) in 2017 Summary of water quality monitoring data for Lam Tsuen River in E-4 2017 Summary of water quality monitoring data for Lam Tsuen River and E-6 Tai Po River in 2017 Summary of water quality monitoring data for Tai Po Kau Stream, E-7 River Water Quality in Hong Kong 2017 3 Shan Liu Stream and Tung Tze Stream in 2017 Summary of water quality monitoring data for Ho Chung River in E-8 2017 Summary of water quality monitoring data for Sha Kok Mei River in E-9 2017 Summary of water quality monitoring data for Tai Chung Hau Stream E-10 in 2017 Summary of water quality monitoring data for Tseng Lan Shue E-11 Stream in 2017 Summary of water quality monitoring data for River Indus in 2017 E-12 Summary of water quality monitoring data for River Beas in 2017 E-13 Summary of water quality monitoring data for River Ganges in 2017 E-14 Summary of water quality monitoring data for Yuen Long Creek in E-15 2017 Summary of water quality monitoring data for Kam Tin River in 2017 E-17 Summary of water quality monitoring data for Tin Shui Wai Nullah E-18 and Fairview Park Nullah in 2017 Summary of water quality monitoring data for Ha Pak Nai Stream, E-19 Pak Nai Stream and Sheung Pak Nai Stream in 2017 Summary of water quality monitoring data for Ngau Hom Sha Stream, E-20 Tai Shui Hang Stream and Tsang Kok Stream in 2017 Summary of water quality monitoring data for Mui Wo River in 2017 E-21 Summary of water quality monitoring data for Tung Chung River in E-23 2017 Summary of water quality monitoring data for Tuen Mun River in E-24 2017 Summary of water quality monitoring data for Pai Min Kok Stream E-26 and Kau Wa Keng Stream in 2017 Summary of water quality monitoring data for Sam Dip Tam Stream E-27 in 2017 Summary of water quality monitoring data for Kai Tak River in 2017 E-28 Appendix F Compliance with the river Water Quality Objectives in 2017 F-1 Appendix G Water Quality Index (WQI) for inland waters of Hong Kong G-1 Appendix H Summary of river water quality improvements in 18 districts H-1 River Water Quality in Hong Kong 2017 4 1. Introduction Rivers and streams in Hong Kong are generally short in length and carry small flows. Many of them have their upstream sections located within water gathering grounds and have been drawn on quite extensively for supplies of potable water. At present, other than those located within water gathering grounds, the primary beneficial uses of the rivers and streams in Hong Kong include the maintenance of aquatic life, general amenity, flood prevention and storm water drainage. The main channel of Shing Mun River is the only watercourse currently used for secondary contact recreation. The Environmental Protection Department (EPD) has initiated a comprehensive river water quality monitoring programme since 1986. It mainly monitors the major rivers flowing through the urban areas, with one or more representative monitoring stations set up at the upstream and downstream sections of the main channels and tributaries. A number of small rivers and streams in the New Territories are also monitored for water pollution control and management purposes. The monitoring programme serves the following purposes: • evaluate the pollution status of river waters; • monitor long-term changes in water quality; • provide a scientific basis for planning water pollution control strategies; • assess the compliance with the key statutory Water Quality Objectives (WQOs); and • compile Water Quality Index (WQI). This report summarises the water quality of rivers and streams covered by EPD’s river monitoring programme in 2017. Annual reports can be downloaded from the EPD’s website: http://wqrc.epd.gov.hk/en/water-quality/river-2.aspx Sample collection at Tai Wai Nullah River Water Quality in Hong Kong 2017 5 2. An overview of Hong Kong’s rivers in 2017 In 2017, the EPD’s river monitoring programme covered 30 watercourses and a total of 82 monitoring stations (Appendix A), as compared with some 14 watercourses and 47 stations when the programme started in 1986. The monitoring programme involved monthly conducting field measurements and collecting water samples for laboratory analyses. Over 40 physico-chemical and biological parameters, including organic matters, nutrients, metals and E. coli were analysed (Appendix B). To assess compliance with the statutory Water Quality Objectives (WQOs), five representative parameters are used, namely pH, suspended solids, dissolved oxygen, 5-day biochemical oxygen demand and chemical oxygen demand (Appendix C). This report presents the annual average compliance rates for individual watercourses as well as overall compliance rates for Hong Kong (Appendix F). For rivers that have more than one monitoring stations, the WQO compliance was expressed as an average of the annual compliance rates of all their individual monitoring stations where full compliance would be indicated by 100%. Similarly, the overall compliance rates for the entire Hong Kong were the averages of that of all the monitoring stations in the territory. The water quality of inland waters in Hong Kong in 2017 continued to be good with an overall compliance rate at 90%, compared with 91% in 2016 and 89% in 2015. The high compliance rates in recent years were the result of the implementation of pollution control legislation, including the Water Pollution Control Ordinance and the Livestock Waste Control Scheme introduced under the Waste Disposal Ordinance, as well as the extension of the sewer network to more villages under the Sewage Master Plans. River Water Quality in Hong Kong 2017 6 Overall WQO compliance in the inland waters of Hong Kong, 1987-2017 Year 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 (Total number of (54) (57) (68) (74) (74) (74) (86) (86) (86) (86) (82) (82) (81) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) monitoring stations) 100 91 91 89 89 89 90 89 90 90 88 87 86 87 84 81 82 82 81 81 80 76 75 73 70 70 68 65 63 WQO Compliance 61 60 61 (By percentage of monitoring stations) monitoring of (By percentage 60 57 50 48 48 40 Figures are rounded to the nearest integer WQO compliance for five representative parameters in the inland waters of Hong Kong, 1987-2017 Year 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 (Total number of monitoring stations) (54) (57) (68) (74) (74) (74) (86) (86) (86) (86) (82) (82) (81) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) (82) 100 90 80 70 60 50 WQO Compliance 40 (By percentage of monitoring stations) monitoring of (By percentage 30 20 Compliance rate for pH objective Compliance rate for BOD objective Compliance rate for COD objective Compliance rate for DO objective ₅ Compliance rate for SS objective River Water Quality in Hong Kong 2017 7 The Water Quality Index (WQI) is relevant to conserving the primary beneficial use of rivers and streams for the maintenance of aquatic life.