For discussion PWSC(96-97)66
on 20 November 1996

ITEM FOR PUBLIC WORKS SUBCOMMITTEE
OF FINANCE COMMITTEE

HEAD 707 - NEW TOWNS AND URBAN AREA DEVELOPMENT
New Territories North Development
(Civil Engineering - Drainage and erosion protection)
70CD - Yuen Long bypass floodway

Members are invited to recommend to Finance Committee -

1. the upgrading of part of 70CD, entitled "Yuen Long bypass floodway - site investigation and consultants’ fees", to Category A at an estimated cost of $41.4 million in money-of-the-day prices; and
2. the retention of the remainder of 70CD in Category B.

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PROBLEM
PROPOSAL
PROJECT SCOPE AND NATURE
JUSTIFICATION
FINANCIAL IMPLICATIONS
PUBLIC CONSULTATION
ENVIRONMENTAL IMPLICATIONS
LAND ACQUISITION
BACKGROUND INFORMATION
70CD - Yuen Long bypass floodway

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PROBLEM

We do not have the necessary in-house resources to carry out the site investigation, environmental impact assessment (EIA) study and detailed design for the proposed Yuen Long bypass floodway ("the floodway") to alleviate flooding problems in Yuen Long Town and its adjacent areas.

PROPOSAL

2. The Director of Territory Development (DTD), with the support of the Secretary for Planning, Environment and Lands, proposes to upgrade part of 70CD to Category A at an estimated cost of $41.4 million in money-of-the-day (MOD) prices for carrying out the necessary site investigation, EIA study and detailed design for the floodway.

PROJECT SCOPE AND NATURE

3. The scope of 70CD comprises the construction of a 3.6-kilometre floodway running along the south facing side of the Yuen Long Highway from the upstream of Yuen Long nullah to Kam Tin floodway. The project also includes the construction of maintenance access roads alongside the drainage channels.

4. The part of the project we now propose to upgrade to Category A comprises¹ -

1. site investigation;
2. an EIA study;
3. detailed design of the drainage channel including a review of existing planning and hydraulic data, and an assessment of opportunities for optimisation of the works to minimize land resumption; and
4. preparation of tender documents and assessment of tenders.

JUSTIFICATION

5. After almost 30 years of continuing and rapid development of Yuen Long Town and its adjacent areas, the capacity of the existing Yuen Long nullah drainage system, completed in the 1960s to serve Yuen Long Town, has become inadequate to protect Yuen Long Town from periodic flooding. As a result, flooding in the area occurs from time to time causing economic loss and disruption in traffic and communication.

6. The "Territorial Land Drainage and Flood Control Strategy Study - Phase II", which was completed in August 1993, recommended the construction of a bypass floodway to divert part of the flow from Yuen Long catchment into Kam Tin floodway (which is at present under construction), as the best option to reduce the flooding risk of Yuen Long Town. The Study also identified the need to proceed with the floodway project, otherwise a significant portion of Yuen Long Town and its adjacent low-lying areas would be flooded by rainstorms. This situation is not acceptable according to the current flood protection standards for urban areas.

7. The proposed bypass floodway will be a trapezoidal-shaped flood relief drainage channel. It will intercept a portion of runoff from the areas to the south of Yuen Long Town and convey the runoff to the Kam Tin floodway and then to Deep Bay. This would bring the existing Yuen Long nullah system to pass a 50-year return period flooding and would relieve Yuen Long Town from unacceptable flooding risk.

8. Before implementing these works, we need to carry out site investigation and detailed design work for the floodway. We also need to conduct an EIA study to assess potential environmental impacts arising from the proposed works and to recommend appropriate mitigation measures. Due to insufficient in-house resources, DTD proposes to engage consultants to undertake supervision of the site investigation, to conduct the EIA study and to carry out the detailed design of the project.

FINANCIAL IMPLICATIONS

9. We estimate the capital cost of the project to be $41.4 million in MOD prices (see paragraph 10 below), made up as follows -

A breakdown by man months of the estimate for consultants’ fees is at the Enclosure. Civil Engineering Department term contractor will undertake the necessary site investigation.

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

11. 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 award the proposed consultancy on a lump-sum basis with provision for inflation adjustment as the consultancy will exceed 12 months.

12. The proposed consultancy has no recurrent financial implications.

PUBLIC CONSULTATION

13. We consulted the Environmental Improvement Committee of the Yuen Long District Board on the proposed scope of study for Yuen Long bypass floodway in October 1996. The Committee supported the proposal. We further presented the Yuen Long District Development Programme to the Yuen Long District Board on 24 October 1996. As part of this process, we briefed Members on the programme for the proposed floodway works. The Board supported the proposal.

ENVIRONMENTAL IMPLICATIONS

14. The proposed consultancy study itself will not have any major adverse environmental implications. As part of the consultancy we will carry out an EIA study to address the potential impacts arising from the construction and operation of the proposed floodway. The estimated cost of the EIA study is $3 million and has been included in the overall cost of the proposed consultancy.

LAND ACQUISITION

15. The proposed consultancy does not require land acquisition.

BACKGROUND INFORMATION

16. We upgraded 70CD to Category B in September 1995.

17. A section of the Yuen Long bypass floodway will intersect with Route 3 (Country Park Section). We are about to complete the detailed design on this section of the floodway and will carry out the construction works in advance under the Route 3 (Country Park Section) project to avoid major traffic disruption which will otherwise arise if this section of the Yuen Long bypass floodway were to be constructed after commissioning of Route 3 (Country Park Section)² .

18. We plan to start the works under the proposed consultancy in March 1997 for completion in February 2001. We will commence the construction of the remaining section of the floodway in March 2001 for completion in March 2004.

1 -- The scope of site investigation, detailed design and preparation of tender docuements under items (a), (c) and (d) covers the whole floodway except the section at the intersection with Route 3 (please see paragraph 17). The EIA study under item (b) is for the whole floodway project.
2 -- This is the subject of a separate PWSC paper PWSC(96-97)65 to be discussed at this same meeting.

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Enclosure to PWSC(96-97)66

70CD - Yuen Long bypass floodway

Breakdown of estimates for consultants’ fees

*MPS = Master Pay Scale

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 1.4.95, MPS pt. 40 = $51,440 p.m. and MPS pt. 16 = $17,270 p.m.)
2. The figures given above are based on estimates prepared by the Director of Territory Development. We will only know the actual man months and fees when we have selected the consultants through the normal competitive system.

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