For discussion PWSC(96-97)88
on 8 January 1997

ITEM FOR PUBLIC WORKS SUBCOMMITTEE
OF FINANCE COMMITTEE

HEAD 709 - WATERWORKS
Water Supplies - Fresh water supplies
34WF - Tan Kwai Tsuen fresh water service reservoir stage II and 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 "Tan Kwai Tsuen fresh water service reservoir stage II and mainlaying works in Tuen Mun area 52" to Category A at an estimated cost of $104.1 million in money-of-the-day prices; and
2. the retention of the remainder of 34WF, retitled "Additional trunk transfer facilities between Yuen Long and Tuen Mun" in Category B.

---

PROBLEM
PROPOSAL
PROJECT SCOPE AND NATURE
JUSTIFICATION

Construction of the Tan Kwai Tsuen fresh water service reservoir stage II
Laying of fresh water trunk mains in Tuen Mun area 52
FINANCIAL IMPLICATIONS
PUBLIC CONSULTATION
ENVIRONMENTAL IMPLICATIONS
LAND ACQUISITION
BACKGROUND INFORMATION
34WF - Tan Kwai Tsuen fresh water service reservoir stage II and additional trunk transfer facilities between Yuen Long and Tuen Mun

---

PROBLEM

The capacities of the Tan Kwai Tsuen fresh water service reservoir stage I and the Tuen Mun treatment works will not be able to meet the growing demand for fresh water in their respective supply zones by 2000 and 2001 respectively.

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 $104.1 million in money-of-the-day (MOD) prices for the construction of the Tan Kwai Tsuen fresh water service reservoir stage II and for carrying out mainlaying works in conjunction with roadworks in Tuen Mun area 52.

PROJECT SCOPE AND NATURE

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

1. construction of the Tan Kwai Tsuen fresh water service reservoir stage II and associated works; and
2. construction of transfer facilities, which include a pumping station and laying of about 7 800 metres of 1 400 millimetres diameter fresh water trunk mains between Yuen Long and Tuen Mun, to transfer treated water from Au Tau treatment works in Yuen Long to Tuen Mun.

4. The part of 34WF we now propose to upgrade to Category A comprises the works in paragraph 3(a) and laying of about 600 metres of fresh water trunk mains under the works in paragraph 3(b).

JUSTIFICATION

Construction of the Tan Kwai Tsuen fresh water service reservoir stage II

5. At present, the area stretching from northern Tuen Mun along the Tuen Mun-Yuen Long Corridor to Yuen Long is served by the Tuen Mun north service reservoir and Wang Chau service reservoir. These two service reservoirs are reaching their full capacity. DWS envisages that the daily fresh water demand in this area will increase from the current level of 44 000 cubic metres to 54 500 cubic metres by the year 2000. The demand will further increase to 97 000 cubic metres per day upon completion of planned developments after 2004. In view of the growing water demand in the area, DWS has planned to construct the Tan Kwai Tsuen fresh water service reservoir to serve the area in the long run. The construction works of the Tan Kwai Tsuen fresh water service reservoir stage I under 193WF¹ had already commenced in June 1994 for commissioning in mid 1997. The stage I reservoir upon completion will be able to meet the daily demand of 50 000 cubic metres. DWS now proposes to construct the Tan Kwai Tsuen fresh water service reservoir stage II to meet the remaining expected demand of 47 000 cubic metres per day in this area beyond 2004.

Laying of fresh water trunk mains in Tuen Mun area 52

6. DWS estimates that the daily water demand in Tuen Mun area will increase from the current level of 195 000 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 special industrial area and the river trade terminal in areas 38 and 47 of Tuen Mun, are fully completed after 2004. The existing Tuen Mun treatment works which can meet a maximum daily water demand of 300 000 cubic metres will not be able to cope with the surge in water demand in this area. DWS has therefore planned to provide additional trunk transfer facilities between Yuen Long and Tuen Mun to transfer treated water from Au Tau treatment works in Yuen Long to Tuen Mun in order to meet the water demand of the planned developments in the area.

7. We now propose to upgrade to Category A a section of about 600 metres of the proposed fresh water trunk mains under 34WF which falls within the project boundaries of 470CL "Footbridge, roads and drains in area 52 (part), Tuen Mun²" . DWS has agreed with Director of Territory Development (DTD) to incorporate this section of mainlaying works into the roadworks contract under 470CL in order to avoid interface problems arising from two contractors working on the same site³ .

FINANCIAL IMPLICATIONS

8. We estimate the capital cost of the project to be $104.1 million in MOD prices(see paragraph 9 below), made up as follows -

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

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 have incorporated the proposed mainlaying works into DTD’s roadworks contract in area 52 of Tuen Mun on a remeasurement basis because the quantities of mainlaying works may vary with actual ground conditions. We will tender the construction works of the Tan Kwai Tsuen fresh water service reservoir stage II and its associated works under a lump-sum contract because we have formed the site and therefore have firm quantities for the majority of the works which are mostly above ground. We shall provide adjustments for inflation in the contracts because the construction period will last longer than 21 months.

11. We estimate the annually recurrent expenditure to be $260,000.

12. This project by itself would lead to an increase in water charges by a maximum of 0.1% in real terms by 2001⁴ .

PUBLIC CONSULTATION

13. 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 proposal and requested us to closely monitor the works to ensure that the traffic in the vicinity will 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. We also consulted the Environmental Improvement Committee of the Yuen Long District Board on 24 July 1996 and the Committee 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 environmental impact assessment would be necessary. We shall control noise, dust and site run-off nuisances during construction to comply with established standards and guidelines by incorporating standard environmental pollution control clauses in the works contracts.

LAND ACQUISITION

15. The proposed works do not require land acquisition.

BACKGROUND INFORMATION

16. In June 1993, Finance Committee upgraded 193WF to Category A, entitled "Yuen Long water supply - Tan Kwai Tsuen fresh water service reservoir stage I and mainlaying" at an estimated cost of $91 million. The scope of the works comprises construction of the Tan Kwai Tsuen fresh water service reservoir stage I and the associated mains, laying of distribution mains and site formation works for Tan Kwai Tsuen fresh water service reservoir stage II.

17. We included 34WF in Category B in September 1995. As regards the works which we now propose to upgrade to Category A, DWS has engaged consultants to undertake the detailed design for the mainlaying works in Tuen Mun area 52 at a cost of $750,000. We will charge this amount to the block allocation under Subhead 9100WX. We have, using in-house staff, also carried out the detailed design work for the Tan Kwai Tsuen fresh water service reservoir stage II. We plan to commence the proposed mainlaying works in early 1997 to tie in with the roadworks programme in area 52 of Tuen Mun. The construction work for the Tan Kwai Tsuen fresh water service reservoir stage II will commence in the latter part of 1997 for completion in late 1999.

18. DWS is continuing with the design work for the remaining trunk main section and the proposed pumping station under the remaining part of 34WF.

(EE1052)

1 - Please refer to paragraph 16 for details of 193 WF.
2 - In July 1996, Finance Committee upgraded 470CL to Category A at an estimated cost of $220.6 million in money-of-the-day prices.
3 -- We have included in the roadworks contract under 470CL the proposed mainlaying works with a condition that the implementation of these works will be subject to the funding approval of Finance Committee. DTD has also specified in the roadworks contract that the mainlaying works shall be excised from the contract unless such works are ordered to proceed within 300 days after the commencement of the contract. The contract commenced in December 1996.
4 -- The increase in water charges is calculated on the assumption that the demand remains static during the period from 1996 to 2001 and the amount of Government subsidy to the waterworks operations is to be contained at the present level.

---

Enclosure to PWSC(96-97)88

34WF - Tan Kwai Tsuen fresh water service reservoir stage II and additional trunk transfer facilities between Yuen Long and Tuen Mun

Breakdown of estimates for consultants’ fees

Notes

1. A multiplier factor of 3 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 1.4.95, MPS pt. 40 = $51,440 p.m. and MPS pt 16 = $17,270 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 work for this project has been included as part of the Consultancy Agreement (CE 11/73 - New Town Development at Tuen Mun), we will only know the actual consultants’ fees upon finalisation of the account of the works contract.

(EE1052)

---