For discussion PWSC(96-97)27
on 26 June 1996

ITEM FOR PUBLIC WORKS SUBCOMMITTEE
OF FINANCE COMMITTEE

HEAD 711 - HOUSING
Water Supplies - Fresh water supplies
141WF - Ngau Tam Mei treatment works - construction

Members are invited to recommend to Finance Committee the upgrading of the remaining part of 141WF to Category A, entitled "Ngau Tam Mei treatment works - construction", at an estimated cost of $2,501.6 million in money-of-the-day prices.

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PROBLEM
PROPOSAL
PROJECT SCOPE AND NATURE
JUSTIFICATION
FINANCIAL IMPLICATIONS
PUBLIC CONSULTATION
ENVIRONMENTAL IMPLICATIONS
LAND ACQUISITION
BACKGROUND INFORMATION

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PROBLEM

We forecast that the total capacity of the existing water treatment works and associated treated water transfer facilities will be inadequate to cope with the increasing water demand by mid-1999 due to anticipated new developments in the north-western areas of the New Territories.

PROPOSAL

2. The Director of Water Supplies (DWS), with the support of the Secretary for Housing, proposes to upgrade the remaining part of 141WF to Category A at an estimated cost of $2,501.6 million in money-of-the-day (MOD) prices for the construction of the water treatment works and the associated water transfer facilities.

PROJECT SCOPE AND NATURE

3. The original scope of 141WF comprises the investigation, design and construction of water treatment works (including a raw water tunnel within the confines of the treatment works), a primary service reservoir, a pumping station at Ngau Tam Mei and associated trunk mains for an initial daily treated water supply of 230 000 cubic metres to the north-western New Territories by mid-1999. There will be adequate provision to allow for future expansion of the proposed system to increase the daily treated water supply to 450 000 cubic metres. The consultant undertaking the feasibility study on the project has identified the need for constructing an additional pumping station for pumping raw water to the proposed treatment works and for widening an existing access road to the proposed treatment works.

4. The scope of the remaining part of 141WF, which we now propose to upgrade to Category A, comprises the following -

1. construction of a water treatment works, including electrical and mechanical works, with an initial capacity of 230 000 cubic metres per day with provision for future expansion to its ultimate capacity of 450 000 cubic metres per day;
2. construction of a primary service reservoir with a capacity of 40 000 cubic metres with provision for future expansion to its ultimate capacity of 80 000 cubic metres to cater for an initial demand of 230 000 cubic metres per day and an ultimate demand of 450 000 cubic metres per day respectively;
3. construction of a raw water pumping station and a treated water pumping station both constructed to its ultimate size of 450 000 cubic metres per day but initially equipped with pumpsets adequate for the output of 230 000 cubic metres per day;
4. construction of approximately 5 200 metres of pipeline of 1.4 metres diameter and approximately 500 metres long raw water tunnel with associated 2 metres diameter raw water main; and
5. construction of road works and slope works associated with the widening of an existing access road to the treatment works.

JUSTIFICATION

5. We have reviewed the demand for water supply in the north-western New Territories, taking into consideration the anticipated new developments in Tin Shui Wai, Yuen Long and Tuen Mun. These include the housing developments in Tin Shui Wai areas 3, 30 and 31 and Tin Shui Wai Reserve Zone, the special industries and port developments in Tuen Mun western areas. We expect the existing water treatment facilities in the north-western New Territories will become inadequate beyond 1998. The existing total daily water treatment capacity available for this supply zone is 630 000 cubic metres. The forecast daily demand during the peak demand season by 1999 is 718 700 cubic metres . There will be a shortfall of 88 700 cubic metres per day during the peak demand season in 1999, which will increase to 206 100 cubic metres per day by 2001 when the forecast daily demand increases to 836 100 cubic metres. We estimate the population in the north-western New Territories to increase from about 809 000 in 1996 to 943 000 and 1 116 000 by 1999 and 2001 respectively.

6. If we do not provide additional water treatment and transfer facilities by mid-1999, we expect a shortage of treated water for new developments in Tin Shui Wai, Yuen Long and Tuen Mun, and for the special industries and port developments in Tuen Mun western areas. The shortage will seriously affect the proposed housing developments in Tin Shui Wai areas 3, 30, 31, Tin Shui Wai Reserve Zone and in the Yuen Long rural areas. Within these areas, there are many development sites earmarked by the Task Force on Land Supply and Property Prices for the supply of additional housing units before 2001.

7. To complete the project before mid-1999, we need to start construction of the project in November 1996.

FINANCIAL IMPLICATIONS

8. We estimate the capital cost of the project to be $2,501.6 million in MOD prices (see paragraph 9 below), made up as follows -

9. Subject to approval, we will phase the expenditure as follows -

10. We have derived the MOD estimate on the basis of the Government's forecasts of trend labour and construction prices for the period 1996 to 2002. We will tender the works contract on a lump-sum basis. The consultant's fee in paragraph 8(b) above is an actual lump sum tendered price provisionally included in a consultancy agreement for the design and construction of the project awarded under 217WF "Ngau Tam Mei treatment works - site investigations and consultants' fees".

11. We estimate the annually recurrent expenditure to be $58.65 million.

PUBLIC CONSULTATION

12. We consulted the Town Planning and Development Committee of the Yuen Long District Board on 13 March 1996 and upon receipt of further information, the Committee confirmed on 2 April 1996 its support of the proposed project.

ENVIRONMENTAL IMPLICATIONS

13. The Environmental Protection Department completed an Environmental Review in 1989 and concluded that this project would not require environmental impact assessment on the condition that Water Supplies Department would carry out a chlorine hazard assessment and further examine the sludge disposal issues.

14. The consultant undertaking the feasibility study completed a further review of environmental issues in May 1995. For construction impacts, we will control noise and dust emissions and site run-off nuisances to comply with established environmental standards and requirements through the implementation of appropriate mitigation measures in the relevant contracts. For sludge disposal, we will undertake measures to dewater the sludge on site prior to disposal at landfill in accordance with the recommendations of the Integrated Sludge Disposal Strategy prepared by Environmental Protection Department in 1993. We will also implement measures to control other operational impacts including the treatment of washwater from reservoir maintenance.

15. The consultant undertaking the feasibility study for the project completed a chlorine hazard assessment in March 1996. The assessment concluded that the potential hazard due to the use and storage of chlorine at the treatment works would comply with the Government's risk guidelines with implementation of appropriate mitigation measures. We will implement the recommended mitigation measures through the relevant works contract.

LAND ACQUISITION

16. We will need to resume 86 private agricultural lots of about 44 890 square metres, clear 29 temporary domestic structures and compensate 19 families. The Director of Lands and the Director of Housing estimate that the compensation and ex-gratia allowances for the proposed resumption and clearance is about $108 million. The Director of Housing will clear the structures in the resumption area and rehouse the affected families in accordance with the current housing policy.

BACKGROUND INFORMATION

17. We upgraded 141WF to Category B in November 1993. In March 1995, Finance Committee approved the upgrading of part of 141WF to Category A as 213WF "Ngau Tam Mei treatment works - laying of a trunk watermain along Castle Peak Road from Long Ha to Yuen Long" with an approved project estimate of $152 million at August 1994 prices. In July 1995, Finance Committee further approved the upgrading of part of 141WF to Category A as 217WF "Ngau Tam Mei treatment works - site investigations and consultants' fees" with an approved project estimate of $71.4 million in MOD prices. The remaining part of 141WF which we now propose to upgrade to Category A comprises the construction of the water treatment works and associated water transfer facilities details of which are given in paragraph 4 above.

18. We have engaged a consultant under 217WF "Ngau Tam Mei treatment works - site investigations and consultants' fees" to carry out site investigations and detailed design of the water treatment works and the associated water transfer facilities. The consultant has completed the site investigations and detailed design incorporating cost-effective treatment processes and the use of the latest technology for the raw water reaching the treatment works. We will invite pre-qualified contractors to submit tenders for the works contract of this project in July 1996, subject to the Finance Committee's approval to upgrade this part of 141WF to Category A.

19. We plan to start construction in November 1996 for completion by mid-1999.

(KK92)

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