For discussion PWSC(97-98)11
on 9 May 1997

ITEM FOR PUBLIC WORKS SUBCOMMITTEE OF FINANCE COMMITTEE

HEAD 704 - DRAINAGE
Civil Engineering - Drainage and erosion protection

59CD - West Kowloon drainage improvement - stages 1, 2 and 3

Members are invited to recommend to Finance Committee -

  1. the upgrading of part of 59CD entitled "West Kowloon drainage improvement, stage 1 works" to Category A at an estimated cost of $464 million in money-of-the-day prices; and

  2. the retention of the remainder of 59CD, retitled "West Kowloon drainage improvement, stages 2 and 3", in Category B.

PROBLEM

West Kowloon is susceptible to flooding due to the inadequate capacity of the existing drainage system in the area.

PROPOSAL

2. The Director of Drainage Services, with the support of the Secretary for Planning, Environment and Lands, proposes to upgrade part of 59CD to Category A at an estimated cost of $464 million in money-of-the-day (MOD) prices for the West Kowloon drainage improvement, stage 1 works.

PROJECT SCOPE AND NATURE

3. Project 59CD on "West Kowloon drainage improvement - stages 1, 2 and 3" comprises three stages of works to be carried out according to a prioritised programme. The part of the project we now propose to upgrade to Category A covers the stage 1 improvement works to approximately 9.2 kilometres of drains at various locations in West Kowloon as indicated in the attached site plan at Enclosure 1. The scope of works comprises the construction of -

  1. about 5.4 kilometres of drain pipes of diameters ranging from 300 millimetres to 1 500 millimetres; and

  2. about 3.8 kilometres of single cell or two cell box culverts, of cell size up to 4 800 millimetres x 3 500 millimetres.

4. The remainder of 59CD comprises construction of the stage 2 improvement works, and investigations, detailed design and construction of the improvement works under stage 3.

JUSTIFICATION

5. West Kowloon, comprising Sham Shui Po, Mong Kok, Yau Ma Tei, part of Tsim Sha Tsui and part of Kowloon City, is a major residential and commercial area. We built the existing drainage system many years ago with its capacity designed to meet the flow requirements and standards for flood protection at that time.

6. Over the years, due to rapid urbanization and development in West Kowloon, pervious land has been paved over and has become impermeable. During heavy rainstorms, a large quantity of rainwater remains on the ground surface instead of dissipating naturally as ground water. The surface run-off then enters into the drainage system within a short time overloading the system, hence causing flooding during severe rainstorms especially in the low-lying areas in West Kowloon.

7. We commissioned a study under 65CD "West Kowloon stormwater drainage improvement study - consultants’ fees and investigation" in June 1994 to identify inadequacies in the existing drainage system and to prepare a drainage master plan for the improvement of the system. The study identified a series of improvement works to the existing drainage system and recommended a three-stage improvement programme.

8. Existing drains that are critically inadequate in capacity need to be replaced by new ones of larger capacity. For example, at Reclamation Street between Waterloo Road and Pitt Street, we propose to replace the existing 300mm diameter drain with a 1 500mm diameter drain. At Waterloo Road between Ho Man Tin Street and Pui Ching Road, we propose to replace the existing
2 500mm x 2 000mm single cell culvert with a 4 500mm x 2 500mm two cell culvert.

FINANCIAL IMPLICATIONS

9. We estimate the capital cost of the proposed stage 1 works to be $464 million in MOD prices (see paragraph 10 below) made up as follows -



$ million


(a) Construction of drainage works


294.2


(i) pipes

90.1



(ii) box culverts

204.1



(b) Consultants’ fees for construction stage


5.7


(c) Resident site staff cost


27.7


(d) Contingencies


26.4




_____

Sub-total


354.0

(at December
1996 prices)

(e) Inflation allowance


110.0




_____


Total


464.0

(in MOD prices)


_____


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

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

Year

$ million
(Dec 1996)

Price
adjustment
factor

$ million
(MOD)

1997 - 98

0.5

1.06750

0.5

1998 - 99

96.2

1.16358

111.9

1999 - 2000

106.0

1.26830

134.4

2000 - 01

105.8

1.38244

146.3

2001 - 02

27.9

1.50686

42.0

2002 - 03

17.6

1.64248

28.9

_____


_____

354.0


464.0

_____


_____

11. We have derived the MOD estimate on the basis of the Government’s forecasts of trend labour and construction prices for the period 1997 to 2003. We will tender the drainage works as a standard remeasurement contract because we are uncertain about the existence and exact locations of underground utilities such as electric cables, telephone lines and water mains. The contract will allow for adjustments to the tender price due to inflation as the contract period will exceed 21 months.

12. The proposed works will not incur additional recurrent expenditure as the works comprise mainly the replacement of old drains.

PUBLIC CONSULTATION

13. We consulted Sham Shui Po, Kowloon City and Yau Tsim Mong District Boards on 12 December 1996, 27 December 1996 and 16 January 1997 respectively on the proposed works including the temporary traffic arrangements and environmental mitigation measures during construction. Members of all three District Boards supported the implementation of the proposed works.

ENVIRONMENTAL IMPLICATIONS

14. The Director of Environmental Protection completed an Environmental Review in August 1995 and concluded that the project would have no long term environmental impacts and an Environmental Impact Assessment was not necessary. For short term impacts during construction, we will control noise, dust and site run-off to within established standards and guidelines through the implementation of recommended pollution control measures in the works contract.

LAND ACQUISITION

15. The project does not require land acquisition.

BACKGROUND INFORMATION

16. We upgraded 59CD to Category B in December 1993. In June 1994, we upgraded part of 59CD to Category A, as 65CD "West Kowloon stormwater drainage improvement study - consultants’ fees and investigation" with an approved project estimate of $15.9 million, to examine the deficiencies of the existing drainage system and to develop a drainage master plan for the improvement of the system. We completed the final study report in December 1995. The study recommended a three-stage improvement scheme.

17. In April 1996, we engaged consultants to carry out site investigations, traffic impact assessment and detailed design for the West Kowloon stormwater drainage improvement stage 1 works under Category D project 84CD "West Kowloon stormwater drainage improvement, stage 1 - site investigation and detailed design" with an approved project estimate of $11.5 million. The consultants have substantially completed the design for the works involved.

18. We plan to start the construction works for stage 1 in January 1998 for completion in April 2001.

19. In April 1997, we upgraded part of 59CD to Category A as 88CD "West Kowloon drainage improvement, stage 2 - consultants’ fees and investigations" to engage consultants to carry out site investigations and detailed design for the stage 2 drainage improvement works. We plan to start the design consultancy for the stage 2 works in June 1997 for completion in December 1999. We plan to start stage 2 drainage improvement works in December 1999 for completion in June 2004.

20. We plan to start the detailed design for the stage 3 works in early 2000. We plan to start the construction works for stage 3 in 2002.

Planning, Environment and Lands Branch
April 1997
(DD1100)

Enclosure 2 to PWSC(97-98)11

59CD - West Kowloon drainage improvement - stages 1, 2 and 3

Breakdown of estimate for consultants’ fees -

Consultants’ staff costs


Estimated
man
months

Average
MPS
salary
point

Multiplier
factor

Estimated
fee
($ million)

(a)Consultants’ fees for construction stage

Professional

Technical

21

39

40

16

3.0

3.0

3.49

2.18

(b) Resident site staff cost

Professional
Technical

106

394

40

16

2.1

2.1

12.33

15.39





_____

Total consultants’ staff costs




33.39





_____

Notes :

  1. A multiplier factor of 3 is applied to the average MPS point to arrive at the full staff costs including the consultants’ overhead 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 in the case of site staff supplied by the consultants.

  2. The figures given above are based on actual fee proposal from the consultants undertaking the investigations, design and construction supervision of the West Kowloon drainage improvement, stage 1 works.

(DD1100)

Last Updated on 16 August 1999