Dongjiang Raw Water

According to the agreement signed between the HKSAR Government and Guangdong Authorities, the Dongjiang water supplied to Hong Kong should conform to the national standard set out for Type II waters (applicable for the abstraction for human consumption in first class protection area) in the "Environmental Quality Standards for Surface Water GB3838-2002". The raw water after treatment by Hong Kong's water treatment works is suitable for drinking. The Guangdong Authorities have carried out the following measures in recent years so as to assure the quality of Dongjiang raw water transferred to Hong Kong :
- Moved the intake of Dongjiang water upstream in 1998 where the water quality is better.
- Commissioned the Bio-nitrification Plant at the Shenzhen Reservoir in early 1999.
- Constructed and put into operation a dedicated aqueduct from the Dongjiang intake to Shenzhen Reservoir in late June 2003.
- Completed works to intercept waste water flowing into the Shenzhen Reservoir in late 2004.
- Diverted discharge of polluted water from Shima River in early 2005 for treatment.
- Construct sewage treatment plants along the Dongjiang to reduce pollution.
- Remove factories which may pollute the Dongjiang.
- Enforce strictly the environmental legislations, regulate the pollution emitters along the Dongjiang, as well as strengthen the supervision and monitoring of wastewater discharge points along the river.
- Step up control over land use planning and polluting activities.
- Enhance the water resource management and real-time monitoring system.
Significant improvement in Dongjiang water quality is observed after the implementation of the above measures.
There have been occasional reports on the water quality in specific areas along the Dongjiang. Pollution in isolated areas does not materially affect the overall quality of raw water transferred to Hong Kong as the flow volume of the Dongjiang is huge. These reports are not representative of the overall water quality of the Dongjiang main stream.
To enable the public in Hong Kong to understand the actual situation, the Department of Environmental Protection of Guangdong Province has regularly provided the water quality data for samples taken from the East Bank Section of Dongjiang's main stream upstream from the intake of Dongjiang water at Taiyuan Pumping Station. The data taken in 2010 is summarised in the following table.

Statistics on Water quality of Dongjiang's Main Stream in 2010 as Monitored at the East Bank Section

Item	Temperature (^oC)	pH	Dissolved Oxygen	Permanganate Index	Chemical Oxygen Demand	5-Day Biochemical Oxygen Demand (BOD5)	Ammoniacal Nitrogen	Total Phosphorus
January	17.5	7.25	6.60	1.90	9.33	2.87	0.463	0.075
March	21.7	7.40	6.17	1.77	5.00	1.00	0.440	0.070
May	23.8	7.21	6.10	1.93	8.67	1.93	0.423	0.095
July	29.6	7.15	6.43	1.93	11.00	2.13	0.407	0.087
September	30.2	7.51	6.87	1.87	8.33	1.40	0.330	0.079
November	21.6	7.12	7.27	1.60	8.33	1.33	0.380	0.044
Yearly Mean	24.1	7.27	6.57	1.83	8.44	1.78	0.407	0.075
GB3838-2002 Type II Standard for Surface Water	-	6 - 9	>=6	<=4	<=15	<=3	<=0.5	<=0.1

Item	Copper	Zinc	Fluoride	Selenium	Arsenic	Mercury	Cadmium
January	0.001	0.025	0.25	0.00024	0.004	0.00002	0.0005
March	0.004	0.025	0.27	0.00033	0.004	0.00002	0.0005
May	0.004	0.025	0.25	0.00060	0.004	0.00002	0.0005
July	0.002	0.025	0.20	0.00050	0.004	0.00002	0.0005
September	0.001	0.010	0.22	0.00030	0.003	0.000005	0.00005
November	0.001	0.010	0.22	0.00030	0.003	0.000005	0.00005
Yearly Mean	0.002	0.020	0.24	0.00038	0.004	0.00002	0.0004
GB3838-2002 Type II Standard for Surface Water	<=1.0	<=1.0	<=1.0	<=0.01	<=0.05	<=0.00005	<=0.005

Item	Chromium (VI)	Lead	Cyanide	Volatile Phenols	Petroleum Hydrocarbons	Anionic Surfactants	Sulphides	Faecal Coliforms (no./L)
January	0.002	0.005	0.002	0.001	0.013	0.07	0.002	759
March	0.002	0.005	0.002	0.001	0.027	0.08	0.002	882
May	0.002	0.005	0.002	0.001	0.027	0.02	0.002	985
July	0.002	0.005	0.002	0.001	0.037	0.14	0.002	814
September	0.002	0.001	0.0013	0.0002	0.033	0.13	0.003	882
November	0.002	0.001	0.0013	0.0002	0.033	0.15	0.003	217
Yearly Mean	0.002	0.004	0.002	0.001	0.028	0.10	0.002	684
GB3838-2002 Type II Standard for Surface Water	<=0.05	<=0.01	<=0.05	<=0.002	<=0.05	<=0.2	<=0.1	<=2000

Note : Except pH and where specified, all units are in mg/L.

For further information on Dongjiang water quality, please visit the homepage of the Environmental Protection Bureau of Guangdong Province at http://www.gdepb.gov.cn/.
With the water quality analysis system at the Muk Wu Pumping Stations where we receive Dongjiang water, WSD monitors the water quality round the clock to operate the treatment processes at treatment works accordingly so as to ensure that the treated water quality complies with the World Health Organization Guidelines for Drinking-water Quality. The water is safe for consumption. Regarding the Dongjiang water quality at Muk Wu Pumping Stations, please visit the web page "Dongjiang Water Quality as received in Hong Kong at Muk Wu Pumping Station".