PWSC(97-98)69
For discussion
on 12 November 1997

ITEM FOR PUBLIC WORKS
SUBCOMMITTEE OF FINANCE COMMITTEE

HEAD 704 - DRAINAGE
Civil Engineering - Drainage and erosion protection
79CD - Stormwater drainage master plan study in Sha Tin and Tai Po

Members are invited to recommend to Finance Committee the upgrading of 79CD to Category A at an estimated cost of $26.2 million in money-of-the-day prices.

PROBLEM

Many areas in the Sha Tin and Tai Po drainage catchment basins are susceptible to flooding due to the inadequacies of the drainage system in the areas.

PROPOSAL

2.The Director of Drainage Services (DDS), with the support of the Secretary for Planning, Environment and Lands, proposes to upgrade 79CD to Category A at an estimated cost of $26.2 million in money-of-the-day (MOD) prices for the appointment of consultants to undertake a drainage master plan study in Sha Tin and Tai Po.

PROJECT SCOPE AND NATURE

3.The boundary of the study area is shown at Enclosure 1. The scope of the study comprises the following -

1. reviewing and assessing the conditions and inadequacies of the existing drainage system;

2. recommending cost-effective improvement measures for the existing drainage system to meet current standards;

3. carrying out an environmental review for the recommended improvement measures;

4. developing a prioritised implementation programme of works based on a cost-benefit analysis of the recommended improvement measures; and

5. preparing a computerised asset inventory and developing an asset management system for the drainage system to facilitate future system maintenance and development appraisal.

JUSTIFICATION

4.Sha Tin and Tai Po are major residential and industrial areas with a total population of over 800 000. Continuing land development in these areas has been creating more and more build-up areas. Rainwater which mostly dissipated as groundwater in undeveloped land in the past will now remain as surface runoff and enter the drainage system, resulting in an increase in the stormwater flow. The existing drainage system, with the main skeleton built fifteen to thirty years ago, is unable to cope with the increasing stormwater flow. These two areas have therefore become susceptible to flooding during heavy rainstorms, causing traffic disruption, damage and economic loss. The flooding problem has aroused public concern as several major flooding instances occurred in these areas in July and August 1997 during heavy rainfall.

5.We completed 68CD " Territorial land drainage and flood control strategy study phase III, sedimentation study - consultants' fees and investigation " in August 1997 with the objective to investigate the effect of sediment on the performance of major river channels in Hong Kong and develop a forward planning for maintenance dredging. The study reveals that some sections of the main drainage channels in Shing Mun River and Lam Tsuen River are inadequate to carry storm runoff under heavy rainstorms. Since Shing Mun River and Lam Tsuen River are two major river channels serving the Sha Tin New Town and the Tai Po New Town, the performance of the drainage channels in these rivers has significant impact on the reliability of the stormwater drainage system in Sha Tin and Tai Po. In this connection, 68CD has recommended a further study to identify improvement measures to these two rivers.

6.The proposed study will examine the condition of the existing drainage system in Sha Tin and Tai Po and assess its performance. We will identify the exact location of flood prone areas and recommend appropriate improvement measures to strengthen the existing system. We will also develop an asset inventory and asset management system for the efficient management and forward planning of the stormwater drainage system.

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

FINANCIAL IMPLICATIONS

8.We estimate the cost of the proposed study to be $26.2 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 -

Year	$ million (Dec 1996)	Price adjustment factor	$ million (MOD)
1997 - 98	1.0	1.06750	1.1
1998 - 99	9.5	1.16358	11.1
1999 - 2000	8.5	1.26830	10.8
2000 - 01	2.3	1.38244	3.2
	21.3		26.2

10.We have derived the MOD estimate on the basis of the Government's forecast of trend labour and construction prices for the period 1997 to 2001. We will tender the proposed consultancy under a lump-sum contract with provision for inflation adjustment because the contract period will exceed 12 months. The consultants will in turn appoint contractors for the survey work on remeasurement basis through a tendering process. The consultants will adopt this form of contract as they cannot determine in advance the exact extent of the survey work required.

11.This project will not give rise to any recurrent expenditure.

PUBLIC CONSULTATION

12.As the study involves investigation and analysis only, we consider public consultation unnecessary. We will consult the public on the consultants' recommendations upon completion of the study.

ENVIRONMENTAL IMPLICATIONS

13.The study will include an environmental review on the recommended drainage improvement works. The proposed study itself will not cause any adverse environmental impacts.

LAND ACQUISITION

14.The study does not require land acquisition. The consultants will examine the land requirement for recommended drainage improvement works.

BACKGROUND INFORMATION

15.The 1995 Policy Address included a commitment to conduct seven drainage master plan studies covering flood prone areas in Hong Kong. We upgraded 83CD "Yuen Long, Kam Tin, Ngau Tam Mei and Tin Shui Wai drainage master plan study", 75CD "Stormwater drainage master plan study in northern Hong Kong Island", 76CD "Stormwater drainage master plan study in Tsuen Wan, Kwai Chung and Tsing Yi", 78CD "Stormwater drainage master plan study in Tuen Mun and Sham Tseng " and 55CD "Drainage master plan study in the Northern New Territories" to Category A in January 1996, May 1996, July 1996 , January 1997 and June 1997 respectively. 79CD is the sixth in the series of the studies we plan to conduct in the Territory. The implementation programme for the seven drainage master plan studies is set out on the map of the " Drainage Master Plan Areas' at Enclosure 3.

16.We upgraded 79CD to Category B in September 1995. We plan to commence the proposed study in January 1998 for completion in October 1999. We will then prepare and obtain agreement on the necessary preliminary project feasibility studies, and will employ consultants to undertake detailed design of the proposed drainage improvement projects. We anticipate that the main construction work will start in mid-2002 for completion in late 2006.

Planning, Environment and Lands Bureau
October 1997

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Enclosure 2 to PWSC(97-98)69

79CD - Stormwater drainage master plan study in Sha Tin and Tai Po

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 1.4.96, MPS pt. 40 = $55,390 p.m. and MPS pt. 16 = $18,595 p.m.)

2.Out-of-pocket expenses are the actual costs incurred. The consultants are 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 consultants through the usual competitive lump- sum fee bid system.

(JJ198)

to abate drainage problems in Sha Tin and Tai Po.