PWSC(97-98)114
For discussion
on 11 February 1998
ITEM FOR PUBLIC WORKS
SUBCOMMITTEE OF FINANCE COMMITTEE
HEAD 709 - WATERWORKS
Public Safety - Landslip prevention
55BL - Stability review of registered slopes maintained by the Water Supplies Department
Members are invited to recommend to Finance Committee -
- the upgrading of part of 55BL, entitled "Stability review of registered slopes maintained by the Water Supplies Department - stage 1", to Category A at an estimated cost of $94 million in money-of-the-day prices; and
- the retention of the remainder of 55BL, retitled "Stability review of registered slopes maintained by the Water Supplies Department - stage 2", in Category B.
PROBLEM
The Director of Water Supplies (DWS) lacks in-house staff resources to implement the recommendations of the Government's Geoguide 5 - "Guide to Slope Maintenance" for those registered slopes maintained by the Water Supplies Department (WSD).
PROPOSAL
2. DWS, with the support of the Secretary for Works, proposes to upgrade part of 55BL to Category A at an estimated cost of $94 million in money-of-the-day (MOD) prices for the engagement of geotechnical engineering consultants to carry out Engineer Inspections and associated minor civil works and provide geotechnical advice on 700 registered slopes maintained by WSD.
PROJECT SCOPE AND NATURE
3. The full project scope of 55BL comprises the following actions to implement the slope maintenance standards promulgated in Geoguide 5 for 700 registered slopes maintained by WSD -
- carrying out "Engineer Inspection for Maintenance" which assesses the state of maintenance and condition of 700 slopes and identifies those slopes which will require subsequent stability assessments or improvement works;
- carrying out minor civil works such as clearance of accumulated debris and repair of cracked slope surfaces in conjunction with the Engineer Inspections;
- preparing maintenance manuals for each slope inspected;
- carrying out site investigation work and laboratory testing of the soil parameters of the slopes identified in (a) above for stability assessment;
- carrying out the slope stability assessments which analyse the overall safety of slopes; and
- designing and carrying out the proposed improvement works.
4. The part of 55BL which we now propose to upgrade to Category A comprises the works described in paragraphs 3(a), 3(b) and 3(c) above.
JUSTIFICATION
5. In July 1996, we promulgated the Geoguide 5 - "Guide to Slope Maintenance" which set out the enhanced standards of good practice for the maintenance of man-made slopes and retaining walls to prevent deterioration to an unsafe state. We have adopted these standards as the minimum requirements for the maintenance of man-made slopes and retaining walls on Government land.
6. At present, WSD is responsible for the maintenance of 856 registered slopes in all. Seven hundred (700) of these slopes are covered by the scope of 55BL. Of the remaining 156 slopes, 148 are slopes adjacent to catchwater channels and tunnels and 8 slopes are included in the Landslip Preventive Measures (LPM) Programme. These 156 slopes will be dealt with under separate funding arrangements.
7. After an examination of the ways and means to implement the recommendations set out in the Geoguide 5, DWS concludes that he does not have the necessary in-house resources to undertake the works. He therefore proposes to engage consultants to carry out the related investigation works for 700 registered slopes under 55BL in two stages. Stage 1 of the project, which we now intend to upgrade to Category A, comprises the "Engineer Inspection for Maintenance" component of the programme to assess the state of maintenance and condition of the slopes inspected; carrying out minor civil works associated with the inspections such as clearance of accumulated debris, removal of undesirable vegetation and repair of cracked slope surfaces; as well as the preparation of a maintenance manual for each slope. Upon completion of the "Engineer Inspection for Maintenance" programme, we will be able to identify any slopes which require subsequent stability assessment and improvement works. We will implement the necessary stability assessment and improvement works so identified under stage 2 of 55BL. In addition, the consultants will also provide emergency geotechnical advice throughout the consultancy period in case landslips should occur.
8. Regarding the remaining 156 registered slopes, 148 are slopes adjacent to adjoining catchwater channels and tunnels at Tai Lam Chung and on Hong Kong Island and Lantau. For these slopes, we will carry out the investigations under two Category D items under Subhead 9100WX "Waterworks, studies and investigation for items in Category D of the Public Works Programme". We will do so in order not to duplicate efforts because some of these slopes may have to be modified after they have been examined. We plan to implement the investigation and improvement works to the remaining 8 slopes under DWS's responsibility through the LPM programme as these are potentially problematic slopes that had been identified under the LPM programme prior to the inclusion of 55BL in Cat. B.
FINANCIAL IMPLICATIONS
9. We estimate the capital cost of stage 1 of the project to be $94 million in MOD prices (see paragraph 10 below), made up as follows -
|
|
$ million
|
|
|
(a) Consultants' fees
|
|
59
|
|
|
(i) Setting up an inventory and inspection database
|
0.8
|
|
|
|
(ii) Engineer inspection for maintenance
|
43.4
|
|
|
|
(iii) Preparation of maintenance manuals
|
9.7
|
|
|
|
(iv) Design and supervision of associated minor civil works
|
3.6
|
|
|
|
(v) Advisory services on an emergency basis
|
1.5
|
|
|
|
(b) Associated minor civil works
|
|
9.3 |
|
|
(c) Contingencies
|
|
6.8 |
|
| Sub-total | 75.1
| (at
December
1996
prices)
|
|
(d) Inflation allowance
|
|
18.9 |
|
| Total | 94.0
| (in MOD
prices)
|
A breakdown by man months of the estimate for consultants' fees is at the Enclosure.
10. Subject to approval, we will phase the expenditure as follows -
|
Year
|
$ million
(Dec 1996)
|
Price
adjustment
factor
|
$ million
(MOD) |
|
1998 - 99
|
20.4
|
1.16358
|
23.7 |
|
1999 - 2000
|
46.5
|
1.26830
|
59.0 |
|
2000 - 01
|
8.2
|
1.38244
|
11.3 |
|
_____
|
|
_____ |
|
75.1
|
|
94.0 |
|
_____
|
|
_____ |
11. We derived the MOD estimates on the basis of Government's forecast of the trend labour and construction prices for the period 1998 to 2001. We will tender the proposed consultancy on a lump sum basis with provision for inflation adjustment because the consultancy period will be longer than 12 months. We will carry out the associated minor civil works using WSD term contractors. Emergency on-site supervision and the provision of services in case of landslip will be on a time charge basis as we will not know the extent of works in advance.
12. The project will not give rise to any annually recurrent expenditure.
13. The increase in water charges brought about by the project is negligible.
PUBLIC CONSULTATION
14. We consider public consultation unnecessary for the proposed consultancy and minor civil works.
ENVIRONMENTAL IMPLICATIONS
15. The proposed consultancy and associated minor civil works will not give rise to long term environmental impacts. For short term impacts arising out of the minor civil works, the Director of Water Supplies will implement standard pollution control measures to control dust, noise and site run-off nuisances to comply with established criteria.
LAND ACQUISITION
16. This project does not require land acquisition.
BACKGROUND INFORMATION
17. We upgraded 55BL to Category B in August 1997. We plan to commence stage 1 of the project in June 1998 for completion in September 1999. We will carry out the remaining part of the project in early 2000 after the completion of stage 1.
Works Bureau
January 1998
(DD1178)
Enclosure to PWSC(97-98)114
55BL - Stability review of registered slopes maintained by the WSD
DETAILS OF CONSULTANTS' FEES
Breakdown of estimates for consultants' fee
|
Consultants' staff costs
|
|
Estimated
man
months
|
Average
MPS*
salary
point
|
Multiplier
factor
|
Estimated
fee
($ million) |
|
(i) Setting up an inventory and inspection database
|
Professional
Technical
|
4
2
|
40
16
|
3
3
|
0.7
0.1 |
|
|
|
|
|
_____ |
|
|
|
|
Sub-total
|
0.8 |
|
(ii) Engineer inspection for maintenance
|
Professional
Technical
|
170
272
|
40
16
|
3
3
|
28.2
15.2 |
|
|
|
|
|
_____ |
|
|
|
|
Sub-total
|
43.4 |
|
(iii) Preparation of maintenance manuals
|
Professional
Technical
|
45
41
|
40
16
|
3
3
|
7.4
2.3 |
|
|
|
|
|
_____ |
|
|
|
|
Sub-total
|
9.7 |
|
(iv) Design and supervision of associated minor
civil works
|
Professional
Technical
|
9
37
|
40
16
|
3
3
|
1.5
2.1 |
|
|
|
|
|
_____ |
|
|
|
|
Sub-total
|
3.6 |
|
(v) Provision of advisory services on emergency cases
|
Professional
Technical
|
6
9
|
40
16
|
3
3
|
1.0
0.5 |
|
|
|
|
|
_____ |
|
|
|
|
Sub-total
|
1.5 |
|
|
|
|
_____ |
|
Total consultants' staff costs
|
|
59.0 |
|
|
|
|
_____ |
* MPS = Master pay scale
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.).
- The figures given above are based on estimates prepared by the Director of Water Supplies. We will only know the actual fees when we have selected the consultant through the usual competitive lump sum fee bidding system.
(DD1178)
