PWSC(97-98)122
For discussion
on 11 February 1998
ITEM FOR PUBLIC WORKS
SUBCOMMITTEE OF FINANCE COMMITTEE
HEAD 704 - DRAINAGE
Civil Engineering - Drainage and erosion protection
80CD - Stormwater drainage master plan study in Sai Kung, South Lantau and Kwun Tong
Members are invited to recommend to Finance Committee the upgrading of 80CD, re-titled "Stormwater drainage master plan study in Sai Kung, East Kowloon and Southern Lantau", to Category A at an estimated cost of $36.6 million in money-of-the-day prices.
PROBLEM
Some areas in the Sai Kung, East Kowloon and Southern Lantau drainage catchment basins are susceptible to flooding due to the inadequacies of drainage systems in these areas.
PROPOSAL
2. The Director of Drainage Services (DDS), with the support of the Secretary for Planning, Environment and Lands, proposes to upgrade 80CD to Category A at an estimated cost of $36.6 million in money-of-the-day (MOD) prices for the appointment of consultants to undertake a drainage master plan study in Sai Kung, East Kowloon and Southern Lantau.
PROJECT SCOPE AND NATURE
3. The boundaries of the study areas are shown at Enclosure 1. The scope of the study comprises -
- reviewing and assessing the condition of, and identifying inadequacies in, the existing drainage systems;
- recommending cost-effective improvement measures for the existing drainage systems to meet current standards;
- carrying out an environmental review for the recommended improvement measures;
- developing a prioritised implementation programme of works based on a cost-benefit analysis of the recommended improvement measures; and
- preparing a computerised asset inventory and developing an asset management system for the drainage systems to facilitate future system maintenance and development appraisal.
JUSTIFICATION
4. Sai Kung has undergone rapid development in recent years. A substantial number of residential developments have been constructed to accommodate a population which has increased from 35 000 in 1983 to 200 000 in 1996. As built-up areas have expanded, rainwater which formerly infiltrated as groundwater in undeveloped land has become surface runoff and enters into the drainage system, resulting in an increase in flow in the system. Flooding has occurred during heavy rainstorms or typhoons because some parts of the existing drainage system do not have adequate hydraulic capacity to cope with a sudden surge in the surface runoff.
5. The study area in East Kowloon consists of major residential, commercial and industrial areas with a total population of 750 000. We built the existing stormwater drainage system in the area about 30 years ago with a capacity designed to meet the flow requirements and standards for flood protection at that time. Over the years, we have made various localised modifications, improvements and extensions to the system. Nevertheless, some parts of the system are still inadequate to meet the current flood protection standards and local flooding has occurred during heavy rainstorms or typhoons.
6. Southern Lantau is a rural residential area with a total population of 8 000. Similar to Sai Kung, existing drainage system has been in place for many years and with the expansion of built-up areas in recent years, there has been an increase in stormwater flow into the existing drainage system. Some parts of the system do not have adequate hydraulic capacity and the area has become susceptible to flooding during heavy rainstorms and typhoons.
7. We therefore propose to conduct a comprehensive study to examine the condition of the existing stormwater drainage systems in Sai Kung, East Kowloon and Southern Lantau, and assess their current performance. We will identify inadequacies in the systems, draw up cost-effective methods to improve their capacity and reliability, and recommend appropriate improvement measures to alleviate the flooding problem. We will also prepare a computerised asset inventory and develop an asset management system for the efficient management and forward planning of the stormwater drainage systems.
8. DDS proposes to engage consultants to carry out the study because of insufficient in-house staff resources.
FINANCIAL IMPLICATIONS
9. We estimate the cost of the proposed study to be $36.6 million in MOD prices (see paragraph 10 below), made up as follows -
|
|
$ million
|
|
|
(a) Consultants' fees for
|
|
16.0
|
|
|
(i) supervising survey work
|
1.4
|
|
|
|
(ii) data collection, asset inventory taking, asset management system development and hydrological/ hydraulic model building
|
6.1
|
|
|
|
(iii) examining conditions and assessing performance of existing systems
|
2.4
|
|
|
|
(iv) developing cost-effective options and a prioritised implementation programme
|
5.6
|
|
|
|
(v) conducting an environmental review
|
0.5
|
|
|
|
(b) Out-of-pocket expenses
|
|
9.0
|
|
|
(i) flow/rainfall survey
|
2.5
|
|
|
|
(ii) manhole survey
|
1.5
|
|
|
|
(iii) CCTV survey
|
2.0
|
|
|
|
(iv) topographical survey
|
3.0
|
|
|
|
(c) Contingencies
|
|
3.0
|
|
|
|
_____
|
|
|
Sub-total
|
|
28.0
|
(at December
1996 prices) |
|
(d) Inflation allowance
|
|
8.6
|
|
|
|
_____
|
|
|
Total
|
|
36.6
|
(in MOD
prices) |
|
|
_____
|
|
A breakdown by man months of the estimate for consultants' fees is at Enclosure 2.
10. Subject to approval, we shall phase the expenditure as follows -
|
Year
|
$ million
(Dec 1996)
|
Price
adjustment
factor
|
$ million
(MOD) |
|
1998 - 99
|
5.0
|
1.16358
|
5.8 |
|
1999 - 2000
|
12.0
|
1.26830
|
15.2 |
|
2000 - 01
|
8.0
|
1.38244
|
11.1 |
|
2001 - 02
|
3.0
|
1.50686
|
4.5 |
|
_____
|
|
_____ |
|
28.0
|
|
36.6 |
|
_____
|
|
_____ |
11. We have derived the MOD estimate on the basis of the Government's forecast of trend labour and construction prices for the period 1998 to 2002. We shall tender the proposed consultancy as a lump-sum contract with provision for inflation adjustment because the contract period will exceed 12 months. The consultants will in turn appoint contractors to carry out the survey work on a remeasurement basis. This will be done through a competitive tendering process. The consultants will adopt this form of contract as they cannot determine in advance the exact extent of the survey work required.
12. This project will not give rise to any recurrent expenditure.
PUBLIC CONSULTATION
13. 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
14. The study will include an environmental review of the recommended drainage improvement works. The proposed study itself will not cause any adverse environmental impact.
LAND ACQUISITION
15. The study does not require land acquisition. In the course of the study, the consultants will examine the land requirement for the recommended drainage improvement works.
BACKGROUND INFORMATION
16. The 1995 Policy Address included a commitment to conduct seven drainage master plan studies covering all flood prone areas in the Territory. We upgraded the following studies to Category A : 83CD "Yuen Long, Kam Tin, Ngau Tam Mei and Tin Shui Wai drainage master plan study" in January 1996, 75CD "Stormwater drainage master plan study in northern Hong Kong Island" in May 1996, 76CD "Stormwater drainage master plan study in Tsuen Wan, Kwai Chung and Tsing Yi" in July 1996, 78CD "Stormwater drainage master plan study in Tuen Mun and Sham Tseng" in January 1997, 55CD "Drainage master plan study in the Northern New Territories" in June 1997 and 79CD "Drainage master plan study in Sha Tin and Tai Po" in December 1997. 80CD, the last of the series of the studies we plan to conduct, covers the three remaining flood prone areas in the Territory, namely Sai Kung, East Kowloon and Southern Lantau. The flooding problem in these areas is not as critical as the areas under the other six studies but improvements are still necessary to alleviate or prevent flooding. As Sai Kung is contiguous to East Kowloon, we have grouped the two areas together, whereas Southern Lantau having the smallest population and slowest pace of development compared with other study areas has been left for inclusion in the last study. Enclosure 3 shows the study boundaries and the implementation programme for the seven drainage master plan studies.
17. We upgraded 80CD to Category B in September 1995. We plan to commence the proposed study in July 1998 for completion in December 1999.
18. We have currently completed the studies for 83CD and are proceeding to carry out the detailed design work for the construction element of the project. The other five ongoing studies are at various stage of implementation and we expect them to be completed on time, with the various detailed design work commencing between mid-1999 and early 2001 for completion between early 2002 and mid-2003. On completion of the study for 80CD, we will also take steps to start detailed design work. We expect to complete the detailed design work by late 2002. We will commence construction work for all the areas between mid-2002 and early 2004 for completion between mid-2006 and mid-2007.
19. We will implement the improvement works using a prioritised approach, with top priority being given to critical flooding blackspots. Where necessary, as we have done in other areas, we will undertake first aid improvement measures, either to remove such blackspots completely or to relieve the effects of flooding within the shortest possible time.
Planning, Environment and Lands Bureau
January 1998
(JJ226)
Enclosure 2 to PWSC(97-98)122
80CD - Stormwater drainage master plan study in Sai Kung, South Lantau and Kwun Tong
Breakdown of estimates for consultants' fees -
|
Consultants' staff costs
|
|
Estimated
man
months
|
Average
MPS
salary
point
|
Multiplier
factor
|
Estimated
fee
($ million) |
|
(a) Supervising survey
|
Professional
Technical
|
5
10
|
40
16
|
3
3
|
0.83
0.56 |
|
(b) Data collection, asset inventory taking, asset management system development and hydrological/ hydraulic model building
|
Professional
Technical
|
20
50
|
40
16
|
3
3
|
3.32
2.79 |
|
(c) Examining conditions and assessing performance of existing systems
|
Professional
Technical
|
8
20
|
40
16
|
3
3
|
1.33
1.12 |
|
(d) Developing cost-effective options and a prioritised implementation programme
|
Professional
Technical
|
20
40
|
40
16
|
3
3
|
3.32
2.23 |
|
(e) Conducting an environmental review
|
Professional
Technical
|
2
3
|
40
16
|
3
3
|
0.33
0.17 |
|
|
|
|
|
______ |
|
Total consultant's staff costs
|
16.00 |
|
Out-of-pocket expenses
|
|
|
|
|
|
(a) Flow/rainfall survey
|
|
|
|
|
2.50 |
|
(b) Manhole survey
|
|
|
|
|
1.50 |
|
(c) CCTV survey
|
|
|
|
|
2.00 |
|
(d) Topographical survey
|
|
|
|
|
3.00 |
|
|
|
|
|
_____ |
|
|
Total out-of-pocket expenses
|
9.00 |
|
|
|
|
|
_____ |
Notes
- 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.)
- 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.
- 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.
(JJ226)
