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205. Head 707 – New Towns and Public Housing (other than Housing Authority). Tsing Yi development. the sum of $6.2 million was awarded in March 1980 for the laying of fresh and salt water pipelines industrial and residential developments on Tsing Yi Island. The works included the laying of 600 mm diameter mild steel watermains and 375 mm diameter asbestos cement watermains along the road reserve of the second carriageway of road TY1 East and the contract was certified as complete in September 1981. In March 1982 a roadworks contract in the sum of $45.7 million was let for the construction of the second carriageway of roads TY1 East and TY3. In June 1982 the roadworks contractor found that in several locations the top of the watermains was exposed during trimming to road formation level and following a survey, it was discovered that over 1 200 metres of the new watermains had been laid without sufficient cover relative to the proposed road levels, thus not giving adequate protection to the pipes. Although it was decided to reduce the cover from the normally acceptable depth of one metre to 0.7 metre, this did not obviate the need for a considerable part of the watermains having to be re-laid to suit the second carriageway level. The re-laying was partly done by the roadworks contractor and partly by the waterworks maintenance contractor. The additional costs including the payment of disruption claims to the roadworks contractor were estimated at $9.5 million. The claims have not yet been finalized but up to mid-September 1985, a total of $6 million has been paid. Whilst the cost of the re-laying work and the claims arising therefrom has been charged to the roadworks project vote, responsibility for the failure to lay the mains to the correct levels in the first place has not yet been accepted by either the New Territories Development Department or the Water Supplies Department.
206. The mainlaying contract formed part of stage two of the Tsing Yi development water supply project and had to proceed ahead of the roadworks contract for the construction of the second carriageway of road TY1 East because there was an urgent need to provide an adequate water supply to the industrial area and to meet fire fighting requirements. Although the mainlaying contract was let two years earlier than the roadworks contract, the Director of Water Supplies was aware of the proposed construction of the second carriageway of road TY1 East because in 1977, in connection with another waterworks contract on Tsing Yi Island, he had been advised by the Director of New Territories Development that the future vertical alignment of the second carriageway would not differ appreciably from the existing carriageway. Whilst the contract specification subsequently drawn up stipulated that the watermains were to be laid with a cover to final surface of one metre, the meaning of “final surface” was not clearly defined in the contract and the necessary vertical profile was not shown on the tender drawings. In this connection, in an internal Water Supplies Department memorandum in January 1980 at the time tenders were invited, the Chief Engineer, Design informed the Chief Engineer, Construction that the alignment and elevation of the pipelines would have to be determined by the Construction Division.
207.
In August 1980, four months after work on the mainlaying contract commenced, supervision of the works was assigned by the Director of Water Supplies to consultants, because of the critical staff situation in the Water Supplies Department. The important point concerning the proposed development of road TY1 East and the need to ascertain the elevation of the watermains was however not mentioned by the Director of Water Supplies in his handing-over notes to the consultants, who became responsible for the supervision of the mainlaying contract in September 1980 until the completion of works in September 1981.
208. After discovery of the insufficient cover of the watermains in June 1982, the Director of Water Supplies sought an explanation from the mainlaying consultants as to why they made no enquiries regarding the proposed road levels and how the final surface was determined in the absence of precise information on the reference datum from where the one metre cover should be taken. The Director expressed the view that the mainlaying consultants should have clarified the matter with the parties concerned if they considered the information on the drawings was inadequate. In reply, in July 1982 the mainlaying consultants stated that they did not have sufficient reasons to believe that they should initiate action on designing the levels of the watermains. The mainlaying consultants claimed they were not aware of the proposed road widening because they were not so informed when supervision of the contract was handed over to them. (It is noted in this connection that in October 1980, shortly after they took over supervision of the mainlaying contract, that the mainlaying consultants had been supplied with two drawings by the roadworks consultants which showed that there would be a future carriageway adjacent to the existing one.) The Director of Water Supplies did not respond to the mainlaying consultants' letter of July 1982 until January 1985, some 21 years later, when he requested the consultants to supply details as to how the final surface as specified in the contract documents had been determined. He noted that the contract drawings supplied to the mainlaying consultants did not give precise information on the reference datum from where the one metre cover should be taken and as there was an item in the bill of quantities for bulk excavation for the removal of illegal dumping, it was not possible for the consultants, without reference to the Water Supplies Department or the roadworks consultants, to determine the final surface. After a further exchange of correspondence the Director expressed the view in May 1985 in a letter to the mainlaying consultants, that the conflicting and incorrect statements and explanations made by them indicated that there had been no proper and sound basis for determining the levels for pipelaying, as it appeared that their objective was to "dig a trench and bury the pipe" and that other considerations had been completely overlooked and ignored during pipelaying. The matter has not yet been resolved.
209. The discovery of insufficient cover of the watermains in June 1982 was made during the construction stage of the roadworks contract rather than the design stage. This resulted, in addition to the cost of re-laying the watermains, in substantial claims for delays and disruption of work by the roadworks contractor, which would have been avoided had the insufficient cover been known during the design stage. In April 1981 the roadworks consultants had forwarded drawings to the Director of Water Supplies requesting information regarding the watermains prior to the letting of the roadworks contract, but the vertical profile of the watermains was not specifically requested. The roadworks consultants
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