For discussion PWSC(96-97)20
on 26 June 1996

ITEM FOR PUBLIC WORKS SUBCOMMITTEE
OF FINANCE COMMITTEE

HEAD 704 - DRAINAGE
Civil Engineering - Drainage and erosion protection
76CD - Stormwater drainage master plan study in Tsuen Wan, Kwai Chung and Tsing Yi

Members are invited to recommend to Finance Committee the upgrading of 76CD to Category A at an estimated cost of $21.8 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
76CD - Stormwater drainage master plan study in Tsuen Wan, Kwai Chung and Tsing Yi

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PROBLEM

We designed and built the existing stormwater drainage system in Tsuen Wan, Kwai Chung and Tsing Yi some 30 years ago. It is now inadequate to meet current flood protection standards.

PROPOSAL

2. The Director of Drainage Services (DDS), with the support of the Secretary for Planning, Environment and Lands, proposes to upgrade 76CD to Category A at an estimated cost of $21.8 million in money-of-the-day (MOD) prices for the appointment of consultants to undertake a drainage master plan study in Tsuen Wan, Kwai Chung and Tsing Yi. The area boundary of the study is shown at Enclosure 1.

PROJECT SCOPE AND NATURE

3. The scope of the project comprises the following -

1. preparing a computerised asset inventory taking and asset management system for the stormwater drainage system to facilitate future system maintenance and development appraisal;

2. (b) reviewing the capacity of the existing stormwater drainage system using hydrological/hydraulic modelling;

3. carrying out an environmental review;
4. examining conditions and assessing performance of the existing stormwater drainage system to identify critical areas requiring improvements; and
5. developing cost-effective options with prioritised implementation programme to upgrade and extend the stormwater drainage system.

JUSTIFICATION

4. Tsuen Wan, Kwai Chung and Tsing Yi are major residential and industrial areas with a population over 700 000. The existing stormwater drainage system serving the areas has been in place for some 30 years. Due to extensive urbanisation and development in the areas, the natural pervious uncultivated land and farm land have become artificial impermeable covered areas. During severe rainstorms, a large proportion of rainwater will remain on the ground surface instead of dissipating as groundwater naturally. The surface runoff then enters into the stormwater drainage system over a short period. As a result, the system is unable to cope with the sudden large amount of stormwater. This leads to more frequent flooding during the rainstorm season, causing damage and losses to the residents.

5. We have made numerous localised modifications and extensions on the drainage system in the past years. However, these measures are not sufficient in preventing flooding. We therefore need to conduct a comprehensive study to identify flood prone areas and investigate cost-effective methods to upgrade the drainage system to current standards of capacity and reliability.

6. The proposed study will examine conditions and assess performance of the existing stormwater drainage system in Tsuen Wan, Kwai Chung and Tsing Yi. After we have identified areas requiring improvements in the drainage system, we will recommend appropriate measures and develop an asset inventory taking and asset management system for the efficient management of the improved drainage system and provide forward planning of the system.

7. DDS proposes to engage consultants to undertake the study because of insufficient in-house staff resources.

FINANCIAL IMPLICATIONS

8. We estimate the cost of the proposed study to be $21.8 million in MOD prices (see paragraph 9 below) made up as follows -

A breakdown by man months of the estimate for consultants' fees is at Enclosure 2.

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

10. We have derived the MOD estimate on the basis of the Government's forecasts of trend labour and construction prices from 1996 to 2000. We will tender the proposed consultancy on a lump-sum basis. We will allow for inflation adjustment in the consultancy agreement as the project duration is more than 12 months.

11. The proposed consultancy will not give rise to any recurrent expenditure.

PUBLIC CONSULTATION

12. As the study only involves investigation and analysis, we consider public consultation unnecessary.

ENVIRONMENTAL IMPLICATIONS

13. The proposed consultancy will not have any adverse environmental impacts. The study will include an environmental review to identify potential environmental concerns, mitigation measures required and the need for an Environmental Impact Assessment.

LAND ACQUISITION

14. The study does not require land acquisition.

BACKGROUND INFORMATION

15. The 1995 Policy Address includes a commitment to conduct seven drainage master plan studies covering all flood prone areas in the Territory. Members approved the upgrading of 83CD "Yuen Long, Kam Tin, Ngau Tam Mei and Tin Shui Wai drainage master plan study" and 75CD "Stormwater drainage master plan study on northern Hong Kong Island" to Cateagory A in January 1996 and May 1996 respectively . 76CD is the third in the series of the studies we plan to conducted. The tentative programme of implementing the seven drainage master plan studies is at Enclosure 3.

16. We upgraded 76CD to Category B in September 1995. The study is scheduled to commence in August 1996 for completion in April 1998.

17. We will accord top priority to the implementation of improvement works which are identified as urgent works in the drainage master plan study. Between May 1998 and early 2000, we envisage endorsing the study results, preparing and agreeing the preliminary project feasibility study, employing consultants and undertaking the detailed design of the project. We anticipate that the main construction work will start in early 2000 for completion in mid 2004.

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Enclosure 2 to PWSC(96-97)20

76CD - Stormwater drainage master plan study in Tsuen Wan, Kwai Chung and Tsing Yi

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 consultant's overheads and profit, as the staff will be employed in the consultant's offices. (At 1.4.95, MPS pt. 40 = $51,440 p.m. and MPS pt. 16 = $17,270 p.m.)

2. Out-of-pocket expenses are the actual costs incurred. The consultant is not entitled to any additional payment for overheads or profit in respect of these items.

3. The figures given above are based on estimates prepared by the Director of Drainage Services . We will only know the actual man months and actual fees when we have selected the consultant through the usual competitive lump sum fee bid system.

(JJ103)

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