PWSC(97-98)65
For discussion
on 12 November 1997

ITEM FOR PUBLIC WORKS
SUBCOMMITTEE OF FINANCE COMMITTEE

HEAD 709 - WATERWORKS
Water Supplies - Fresh water supplies
34WF - Additional trunk transfer facilities between Yuen Long and Tuen Mun

Members are invited to recommend to Finance Committee -

1. the upgrading of part of 34WF, entitled "Mainlaying between Yuen Long and Tan Kwai Tsuen" to Category A at an estimated cost of $122.8 million in money-of-the-day prices; and

2. the retention of the remainder of 34WF, retitled "Additional trunk transfer facilities between Tan Kwai Tsuen and Tuen Mun" in Category B.

PROBLEM

The capacity of the Tuen Mun water treatment works will not be able to meet the growing fresh water demand generated from developments in Tuen Mun by 2001.

PROPOSAL

2.The Director of Water Supplies (DWS), with the support of the Secretary for Works, proposes to upgrade part of 34WF to Category A at an estimated cost of $122.8 million in money-of-the-day (MOD) prices for laying part of the required water main between Yuen Long and Tan Kwai Tsuen.

PROJECT SCOPE AND NATURE

3.The full scope of works under 34WF comprises -

1. construction of a pumping station at Tan Kwai Tsuen;

2. laying of approximately 2.9 kilometres of 1400 mm diameter fresh water trunk main between Tuen Mun and Tan Kwai Tsuen; and

3. laying of approximately 2.9 kilometres of 1400 mm diameter fresh water trunk main between Yuen Long and Tan Kwai Tsuen.

4.The part of 34WF we now propose to upgrade to Category A comprises the works mentioned in paragraph 3(c) above.

JUSTIFICATION

5.DWS estimates that the daily water demand in Tuen Mun area will increase from the current level of 206 000 cubic metres to 328 000 cubic metres in 2001. The demand will further increase to 497 000 cubic metres when all planned developments, including the industrial area and the river trade terminal in areas 38 and 47 of Tuen Mun, are fully completed after 2004. The existing Tuen Mun water treatment works which has a capacity to meet a maximum daily water demand of 300 000 cubic metres will not be able to cope with the anticipated increase in water demand in this area. As there is no suitable site available in the immediate vicinity of the treatment works, it is impractical to further increase its capacity. DWS therefore plans to provide additional trunk transfer facilities between Yuen Long and Tuen Mun under 34WF to transfer treated water from Au Tau water treatment works in Yuen Long to Tuen Mun in order to meet the anticipated fresh water demand in Tuen Mun.

6.DWS has another project under B270WF¹Yuen Long water supply - Tan Kwai Tsuen north fresh water service reservoir " to augment the existing water supply systems in Yuen Long and Tin Shui Wai. The mainlaying works described in paragraph 3(c) above follows the same route and a similar construction schedule as part of the mainlaying works proposed under B270WF. To avoid interface problems arising from two contractors working on the same site, to minimize inconvenience to the public and to reduce costs, DWS proposes to construct these watermains under one contract.

FINANCIAL IMPLICATIONS

7.We estimate the capital cost of the project to be $122.8 million in MOD prices (see paragraph 8 below), made up as follows -

A breakdown by man-months of the estimate for consultants' fee including resident site staff expenses is at the Enclosure.

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

9.We have derived the MOD estimates on the basis of the Government's forecast of trend labour and construction prices for the period from 1998 to 2003. As the quantities of mainlaying works may vary with the actual ground conditions, we will tender the mainlaying works under a standard remeasurement contract. We will provide for adjustment due to inflation in the mainlaying contract because the construction period will be longer than 21 months.

10.We estimate the additional annually recurrent expenditure to be $191,000.

11.This project by itself will lead to an increase in water charges by a maximum of 0.05% in real terms² .

PUBLIC CONSULTATION

12.We consulted the Environmental Improvement and District Development Committee (EIDDC) of the Tuen Mun District Board (TMDB) on 12 July 1996. The EIDDC of the TMDB supported the project and requested us to closely monitor the works and strictly enforce the contract provisions to ensure that the traffic in the vicinity would not be adversely affected during the construction period. We will address EIDDC's concern by incorporating the relevant clauses into the works contracts and closely supervising the construction activities of the contractors during construction stage.

13.We also consulted the Environmental Improvement Committee of the Yuen Long District Board on 24 July 1996 on 34WF and the Committee supported the project. We further consulted the Environmental and Improvement Committee and the Traffic and Transport Committee of the Yuen Long Provisional District Board on the combined work scheme for 34WF and B270WF on 24 July 1997 and 31 July 1997 respectively. The Committees supported the proposal.

ENVIRONMENTAL IMPLICATIONS

14.The Director of Environmental Protection completed an environmental review in December 1994 and concluded that the project would have no long term adverse environmental impact and no Enviromental Impact Assessment would be necessary. We will control noise, dust and site run-off nuisances during construction to comply with established standards and guidelines by incorporating relevant environmental pollution control clauses in the works contracts.

LAND ACQUISITION

15.The proposed works do not require land acquisition.

BACKGROUND INFORMATION

16.We upgraded 34WF to Category B in Setpember 1995. In January 1997, Finance Committee approved the upgrading of part of 34WF to Category A as 229WF "Tan Kwai Tsuen fresh water service reservoir stage 2 and mainlaying works in Tuen Mun area 52" at an estimate cost of $104.1 million in MOD prices. The scope of works of 229WF comprises the construction of the Tan Kwai Tsuen fresh water service reservoir stage 2 and construction of part of the water trunk mains to transfer treated water from Au Tau treatment works in Yuen Long to Tuen Mun.

17.As regards the works which we now propose to upgrade to Category A, DWS has substantially completed the detailed design for the proposed mainlaying works by engaging consultants at a cost of $3.7 million which we have charged to block allocation subhead 9100WX "Waterworks, studies and investigations for items in Category D of the Public Works Programme".

18.At present, the contractors generally need several months to acquire the necessary pipe materials from suppliers before they can physically start the mainlaying works on site. To meet the target programme of the project B270WF and to ensure that the water supply will be available for the housing projects in Tin Shui Wai, the Secretary for Housing has approved the inclusion of an item under the block allocation subhead B100HX " Minor housing development related works, studies and investigations for items related to housing development in Category D of the Public Works Programme " at an estimated cost of $4.9 million for purchasing some pipe materials for B270WF in advance of the works contracts. In so doing, the selected contractors will have some of the necessary pipe materials to start mainlaying works immediately upon commencement of the contracts. In order that water mains under 34WF can be laid concurrently with those of B270WF under one contract, we have also arranged for advance purchase of about 5% of the pipe materials required for 34WF at an estimated cost of $1.0 million and shall charge the expenditure to block allocation Subhead 9100WX. We plan to commence the proposed mainlaying works in April 1998 for completion in October 2000 to tie in with the works under B270WF.

19.DWS is continuing with the design work for the remaining trunk main section and the proposed pumping station under the remaining part of 34WF with a target to start the construction works in December 1998 for ocmpletion in March 2001.

Works Bureau
November 1997

1.We upgraded B270WF to Category B in August 1995. A related paper, PWSC(97-98)66, for the upgrading of B270WF under Head 711 to Category A is also submitted for Members' approval at this meeting. DWS plans to start the mainlaying works for B270WF in April 1998 for completion in October 2000.

2.The increase in water charges is calculated on the assumption that the demand remains static during the period from 1997 to 2003 and the amount of Government subsidy into the waterworks operations is to be contained at the present price level.

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Enclosure PWSC(97-98)65

34WF - Additional trunk transfer facilities between Yuen Long and Tuen Mun

Breakdown of estimates for consultants' fee

" MPS = Master pay scale

Notes

(1) A multiplier factor of 3.0 is applied to the average MPS point to arrive at the full staff costs including the consultants' overheads and profit, as the staff will be employed in the consultants' offices (At 1.4.96, MPS pt. 40 = $55,390 p.m. and MPS pt. 16 = $18,595 p.m.). A multiplier factor of 2.1 is applied to the average MPS in the case of site staff supplied by the consultants.

(2) The figures given above are based on estimates prepared by the Director of Water Supplies. Since the consultancy works for this project will be included as part of the consultancy Agreement No. 56/96 - "Yuen Long water supply - Tan Kwai Tsuen north fresh water service reservior", we will only know the actual consultants' fees upon finalisation of the account of the works contract.

(JJ200)