For discussion PWSC(95-96)99
on 7 February 1996

ITEM FOR PUBLIC WORKS SUBCOMMITTEE
OF FINANCE COMMITTEE

HEAD 705 - CIVIL ENGINEERING
Public Safety - Landslip prevention
51BL - Systematic identification and registration of slopes

Members are invited to recommend to Finance Committee -

1. an extension in the project scope of 51BL for the identification and registration of an additional 20 000 man-made slopes¹ in the Territory; and
2. an increase in the approved project estimate of 51BL from $41.8 million by $57.5 million to $99.3 million in money-of-the-day prices.

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PROBLEM
PROPOSAL
PROJECT SCOPE AND NATURE
JUSTIFICATION
FINANCIAL IMPLICATIONS
PUBLIC CONSULTATION
LAND ACQUISITION
ENVIRONMENTAL IMPLICATIONS
BACKGROUND INFORMATION
Comparison of Breakdown of Estimates for Consultants’ Fees by Man Months of the
Approved and Revised Project Estimates
Comparison of the Approved and Revised Project Estimates

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PROBLEM

The number of slopes in the Territory requiring registration is 20 000 more than the original estimate of 30 000. The technical complexity of slope identification and registration process is more complicated than we originally anticipated. The approved project estimate of 51BL is insufficient to cover the additional works we wish to incorporate under the project.

PROPOSAL

2. The Director of Civil Engineering (DCE), with the support of the Secretary for Works, proposes to increase the approved project estimate of 51BL from $41.8 million by $57.5 million to $99.3 million in money-of-the-day (MOD) prices to include the identification and registration of an additional 20 000 man-made slopes and to employ additional consultants’ professional and technical staff for the identification and registration process.

PROJECT SCOPE AND NATURE

3. The original project aimed to compile a comprehensive Catalogue of Slopes involving about 30 000 man-made slopes and comprised -

1. a systematic search for and identification of about 30 000 man-made slopes in the Territory for registration, using Aerial Photograph Interpretation (API) techniques;
2. an inspection programme of the slopes identified, which includes examining the slope conditions, recording the relevant information and recommending any follow-up actions together with a pilot study for definitive determination of maintenance responsibility in two areas, namely Magazine Gap Road and Sai Sha Road, covering about 400 slopes; and
3. the establishment of a computerised, easy-to-understand Catalogue of Slopes on a local area network within the Civil Engineering Department (CED).

4. The extended project aims to extend the above scope for compiling a comprehensive Catalogue of Slopes involving some 50 000 man-made slopes.

JUSTIFICATION

5. The Finance Committee approved the upgrading of 51BL to Category A at an estimated cost of $41.8 million on 1 July 1994. At that time, we estimated the project cost based on the estimated resources required to complete work on 30 000 slopes. The figure of 30 000 slopes was calculated on the basis of the number of slopes that we had identified within a small control area in the Territory. Since July 1994, we have already identified and registered a total of 10 000 slopes in addition to the 12 000 slopes in the existing catalogue. According to more reliable figures from the latest findings, we expect the number of slopes in the Territory requiring registration will increase from 30 000 by 20 000 to 50 000. DCE considers it necessary to seek additional funds and an extension in project scope to reflect this additional work. The additional funds required will allow for the considerable increase in the number of slopes and the total identification and inspection time being slightly longer than originally anticipated. These funds will also cover the additional costs of the provision of more equipment and other related expenses such as transport costs for site inspections by the consultants’ staff.

6. We have also found the slope identification process to be much more complex and time consuming. For example, in highly disturbed land (clusters of cut/fill slopes, and/or retaining walls close together) and cemeteries where the latest topographic maps do not clearly show slope features, we have to search for past as-built records to define the identified slopes on topographic maps. In addition, in the less developed areas where a large proportion of the slopes are not contained in the existing catalogue, the slope identification process is time-consuming since API specialists cannot refer to the existing catalogue for initial identification

7. Due to the increase in the general complexity of the identification work that demands more input by professional staff, we need to adjust appropriately the ratio of professional to technical staff to reflect the more complicated nature of the works. Enclosure 1 gives a detailed comparison of the original estimate of consultants’ fees and the revised estimate.

8. The project is currently being carried out by consultants’ staff seconded to CED. Because of the expected large increase in the number and complexity of slopes to be registered, DCE considers it necessary to increase the level of consultant staff resources. We originally expected to complete the exercise by July 1997. If we maintain the existing level of consultant staff, it would take about 6 more years to complete the whole exercise for 50 000 slopes in the new catalogue. Having regard to the importance of public safety, we aim to complete the compilation of the new catalogue before the end of 1997. We thus require an appropriate increase in consultants’ staff resources if we are to meet this target date.

9. Enclosure 2 gives a detailed breakdown of the reasons for the proposed increase in project estimate.

FINANCIAL IMPLICATIONS

10. We estimate the revised project estimate of the project to be $99.3 million in MOD prices (see paragraph 11 below) which is made up as follows -

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

We derive the MOD estimate on the basis of the Government’s forecasts of trend labour and construction prices over the period between 1995 and 1998.

12. The proposed increase in the approved project estimate will increase the annually recurrent expenditure from $120,000 by $80,000 to $200,000 for maintenance of the computer hardware and software.

PUBLIC CONSULTATION

13. As the revised scope of the project is mainly due to the increase in the estimate of the number of slopes in the Territory for identification and registration, we consider that we do not require any public consultation.

LAND ACQUISITION

14. The project does not require land acquisition.

ENVIRONMENTAL IMPLICATIONS

15. There is no direct environmental impact arising from the proposed study which will lead to the compilation of a Catalogue of Slopes.

BACKGROUND INFORMATION

16. Members upgraded this project to Category A on 1 July 1994 with an approved project estimate of $41.8 million for the systematic identification and registration of slopes.

17. We commenced work on this project in July 1994 and subject to Members approval of the additional funds that we are now seeking, we aim to complete the project by the end of 1997. Professional and technical staff seconded by consultants to the CED are carrying out the works.

1 -- Man-made slopes fall into three categories : cut slopes (including associated retaining walls) and retaining walls of more than three metres in height; fill slopes (including associated retaining walls) of more than five metres in height; and fill slopes (including associated retaining walls) of less than 5 metres in height which pose a direct risk to life in the event of failure.
2 -- This is the actual expenditure incurred from 21 July 1994 to 31 March 19995 for the project tasks involving the identification and registration of about 3000m slopes, the completion of the pilot study for definitive determination of maintenance responsibility as part of the project scope mentioned in paragraph 3(b) above and the preparation of the feasibility study report for the establishment of the computerised Catalogue of Slopes.

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Enclosure 1 to PWSC(95-96)99

Comparison of Breakdown of Estimates for Consultants’ Fees by Man Months of the

Approved and Revised Project Estimates

Notes

1. The consultant will be working in Geotechnical Engineering Office of the Civil Engineering Department.
2. The average estimated cost per professional man month for items (a) and (b) is about equivalent to an Engineer on MPS point 43.
3. The average estimated cost per professional man month for item (c) is about equivalent to an Engineer on MPS point 38.
4. The average estimated cost per technical man month for items (a) and (b) is about equivalent to a Technical Officer on MPS point 21.
5. The average estimated cost per technical man month for item (c) is about equivalent to a Technical Officer on MPS point 11.
6. The figures given above are based on estimates prepared by the Civil Engineering Department. The actual fees can only be known when the consultants have nominated the seconded staff.

1 -- We convert the approved project estimate (Dec 93) to approved project estimate (Dec 94) by using the 10% trend labour and construction index for the year 1994

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Enclosure 2 to PWSC(95-96)99

Comparison of the Approved and Revised Project Estimates

A comparison of the approved and revised project estimates is as follows -

2. As regards (a), of the total increase of $10.6 million -

1. $6.6 million is due to the increased number of slopes expected to be dealt with under the project; and
2. $4 million is due to the complexity of the slope identification process. We did not fully appreciate the complexity at the time of the original estimate as the work content was based on limited mapping coverage of certain land classes.

3. As regards (b), of the total increase of $22 million -

1. $16.9 million is for the inspection of the 20 000 slopes in excess of the original estimate of 30 000 slopes; and
2. $5.1 million is due to the actual inspection time being about 13% longer than the original estimated.

4. As regards (c), of the total increase of $2.4 million -

1. $0.5 million is for the provision of additional professional staff resources to study and review the computing requirement for an increased Catalogue size of 50 000 slopes; and
2. $1.9 million is for the provision of technical staff resources to carry out the additional data input for the increased Catalogue size of 50 000 slopes.

5. As regards (d), the total increase of $0.7 million is due to the need for a higher capacity of hardware facility to cater for the increased Catalogue size.

6. As regards (e), of the total increase of $2.3 million -

1. $2.1 million is for the increase in transport costs for site inspections by consultants for the estimated increase of 20 000 slopes; and
2. $0.2 million is for the provision of equipment and tools for the additional seconded staff to handle the estimated increase of 20 000 slopes.

7. As regards (f), the total increase of $2.7 million is in line with the proposed increase in the approved project estimate.

1 -- We convert the approved project estimate (Dec 93) to approved project estimate (Dec 94) by using the 10% trend labour and construction index for the year 1994.

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