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LCQ1: Water quality of the New Yau Ma Tei Typhoon Shelter

     Following is a question by the Hon Priscilla Leung Mei-fun and a reply by the Secretary for the Environment, Mr Edward Yau, at the Legislative Council meeting today (December 15):


     Recently a local organisation in Kowloon West, in collaboration with an academic institute, conducted water quality tests in the New Yau Ma Tei Typhoon Shelter (NYMTTS) in the vicinity of the portal of the Western Harbour Crossing.  The findings revealed that the levels of both dissolved oxygen and Escherichia Coli (E. coli) in the marine water sampled from NYMTTS did not comply with the statutory limits set out in the Statement of Water Quality Objectives (Western Buffer Water Control Zone), a subsidiary legislation under the Water Pollution Control Ordinance, with the E. coli count exceeding the limit by as much as 180 times.  Yet, in reply to a question raised by a Member of this Council on October 20 this year, the Environment Bureau advised that "the monitoring results over the past three years (2007-2009) show a continuous improvement in marine water quality.  The compliance rate of marine water quality for 2009 exceeds 90%, comparing favourably with the 2008 figure.  The Environmental Protection Department (EPD) has not received any complaint about odour from the marine water".  In this connection, will the Government inform this Council:

(a)  whether NYMTTS falls within the areas where the marine water quality is subject to monthly monitoring by the marine monitoring station set up off the coast of West Kowloon by EPD; if so, of the data on dissolved oxygen and E. coli in the marine water obtained from NYMTTS in the past three years, as well as whether the data complied with the statutory limits;

(b) whether at present the authorities remove sludge from NYMTTS on a regular basis; if so, the frequency of such removal work, whether the authorities have assessed the effectiveness of the work; and, in addition to the recently completed Feasibility Study of the Review of West Kowloon and Tsuen Wan Sewerage Master Plans, whether the authorities will conduct other studies to explore new ways to further alleviate the problem of water pollution in NYMTTS; and

(c) whether the authorities have assessed if the environmental pollution problem affecting the areas around NYMTTS will in the long run have an impact on the image and operation of the future West Kowloon Cultural District; if the assessment outcome is in the affirmative, whether the authorities will consider expediting the plan to relocate the New Yau Ma Tei Public Cargo Working Area adjacent to NYMTTS, and of the details of the relocation schedule; if it has not conducted an assessment, whether it will do so?


Mr President,

(a) The Marine Water Quality Monitoring Programme of the Environmental Protection Department (EPD) covers the monitoring of water quality in typhoon shelters.  A monitoring station has been set up at the New Yau Ma Tei Typhoon Shelter (NYMTTS) where the EPD regularly collects marine water samples from three depths, namely near the sea surface (Surface), in the middle layer of the sea (Middle) and near the sea bed (Bottom) for water quality monitoring, which covers analyses of more than 20 physical, chemical and microbiological parameters, including dissolved oxygen (DO) and E. coli levels.

     The NYMTTS is located within the Victoria Harbour Water Control Zone (VHWCZ) rather than the Western Buffer Water Control Zone.  The Government has set Water Quality Objectives (WQOs) for the VHWCZ under the Water Pollution Control Ordinance (WPCO), based on the beneficial uses of the Victoria Harbour for marine navigation and the anchoring of vessels.  As the beneficial uses of Victoria Harbour and NYMTTS do not cover activities for mariculture, swimming or secondary contact recreation, no statutory WQO on E. coli level has been set for the VHWCZ.

     Based on the beneficial uses of Victoria Harbour and NYMTTS, the WQOs for DO levels as declared under the WPCO stipulate that, for 90% of the sampling occasions during the whole year, the depth-averaged DO concentration and bottom DO concentration should not fall below 4 mg per litre and 2 mg per litre respectively. Over the past three years (2007 to 2009), the DO concentration in all the samples of bottom water was over 2 mg/L, meeting the WQOs for bottom DO concentration. Regarding the annual average values of the depth-averaged DO concentration, they were 3.6 mg/L for 2007, 4 mg/L for 2008 and 4.5 mg/L for 2009. However, since the depth-averaged DO concentration during each year could not comply with the criterion of 4 mg/L in 90% of the sampling occasions, the WQO for the depth-averaged DO concentration could not be fully complied with for the past three years. As regards the E. coli levels, although no statutory WQO was stipulated, the annual average E. coli levels have decreased significantly in the past three years, with count per 100 ml at 5,200 for 2007, 1,700 for 2008 and 930 for 2009.

     The water quality in the NYMTTS has improved significantly over the past decade.  The annual average values of both the depth-averaged DO concentration and the bottom DO concentration were 3 mg/L in 2001, and increased by 50% to 4.5 mg/L in 2009. Over the same period, the annual average E. coli levels in NYMTTS decreased by 91% from 11,000 count per 100ml to 930 count per 100ml.

(b)  The depth-averaged DO concentration in the NYMTTS did not meet the WQOs because waters in the western part of Victoria Harbour near the West Kowloon are relatively calm.  The breakwater in the typhoon shelter also impedes the exchange of water between the typhoon shelter and Victoria Harbour.  Another factor is that the pollution sources have not been fully intercepted from discharge into the typhoon shelter, resulting in siltation inside the storm water drains and sediments to accumulate at the nearshore seabed of the typhoon shelter.

     To improve the water quality and mitigate the odour problem of the NYMTTS, the EPD has been implementing a series of measures jointly with other departments to reduce the discharge of pollutants into the typhoon shelter.  Since 2004, the Government has installed six dry weather flow interceptors in the storm water drainage system along the upstream area of NYMTTS. These interceptors serve to intercept polluted flow in dry seasons and to convey the flow to the sewerage system for proper treatment.

     Besides, the EPD conducts inspections regularly to identify problems of misconnections of private building sewers to storm water drains resulting in the discharge of foul water into the typhoon shelter, and takes appropriate action to rectify the misconnections.  Since 1999, the EPD has successfully rectified more than 460 cases of misconnections, equivalent to reducing the water polluting load of a population of over 80,000.  The EPD will step up follow-up and enforcement actions jointly with the Buildings Department and with the assistance of District Offices to tackle the illegal connection and discharge cases, so as to rectify the misconnections of private buildings as soon as possible.

     The EPD has recently completed the Review of West Kowloon and Tsuen Wan Sewerage Master Plans, which contains recommendations on a series of works targeting the NYMTTS to mitigate the pollution caused by discharge from the storm water drains into the typhoon shelter.  They include proposal for installing a new dry weather flow interceptor near the outlet of the Cherry Street box culvert and improving the operation of existing interceptors.  As a short term measure, the desilting of box culvert outlet will be increased from two times to three times a year.  The next desilting of storm water drains will begin soon and is expected to be completed in mid-January 2011.

     Siltation on the seabed of typhoon shelters also affects the safety of fairways.  The Marine Department (MD), therefore, conducts regular hydrographic surveys in typhoon shelters and nearby waters.  Based on the latest data, the MD will determine whether safety of maritime navigation is affected and initiate related maintenance dredging to ensure the safety of fairways.  The Civil Engineering and Development Department is responsible for the implementation of the associated dredging works, and is planning for the next dredging works to be conducted in early 2011.  Concerned departments will closely monitor the effectiveness of the above follow-up work, and will report progress to the relevant District Council.

     Moreover, the Government is committed to improving the water quality of Victoria Harbour, including the coastal waters of West Kowloon.  The water quality of Victoria Harbour has improved significantly since the Harbour Area Treatment Scheme (HATS) Stage 1 was commissioned in end-2001, with the overall E. coli level decreased by 50% and the DO level increased by 10%.  To further improve the water quality of Victoria Harbour, the Advance Disinfection Facilities of HATS Stage 2A were commissioned in March 2010.  According to the water quality monitoring data from March to November 2010, the E. coli level in the western part of Victoria Harbour from Stonecutters Island to Sham Tseng has further reduced.  The level fell by over 50% compared with that in 2009, i.e. before the commissioning of the disinfection facilities. The Government has further invested about $17 billion to fast track the works of HATS Stage 2A.  We expect that the water quality of Victoria Harbour will further improve upon the full commissioning of the HATS Stage 2A in 2014.

(c)  The three conceptual plans of the West Kowloon Cultural District (WKCD) have been on display in a recent public engagement exercise.  The conceptual plan consultants of the WKCD Authority have made preliminary environmental assessment of the odour problem of the NYMTTS.  The consultants consider that the odour problem can be mitigated continuously through the various improvement measures taken by the government departments concerned.  The WKCD Authority will make further environmental impact assessment when it prepares the development plan next year.

     The New Yau Ma Tei Public Cargo Working Area (PCWA), commissioned in 1993, is the busiest among the eight PCWAs in Hong Kong.  It mainly handles containers and general cargoes, and provides about 2,400 jobs for the transport and related trades. The tender results and the occupancy rates of the berths indicate that there remains a strong demand for the PCWA from the freight and port sectors.  Therefore, the Government has no plan to close or relocate the PCWA at the present moment.

Ends/Wednesday, December 15, 2010
Issued at HKT 12:59


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