7.119 The Managing Director referred to the statement by the Director of Water Supplies at the first hearing, that the Design Division of the Water Supplies Department when passing the works to the Construction Division had given. instructions that the Construction Division should, when executing the work, determine the final road level. Following this vital instruction it should have been automatic for the Construction Division to write to the New Territories Development Department to ascertain the status of the road design and how this would affect the pipeline. He was not aware that an enquiry of this nature had been made in the first six months of the mainlaying contract when staff of the Construction Division had been on site. On the assumption that the instruction was vital and given that the matter had been drawn to their attention specifically, there was a fundamental error on the part of the Construction Division. 7.120 The Managing Director referred to the statement by the Director of Water Supplies at the first hearing, that the Design Division had obtained drainage drawings from the New Territories Development Department which the mainlaying consultants were also supposed to have received. He wondered why these apparently critical drawings had been ignored at that time by experienced engineers in the Design and Construction Divisions of the Water Supplies Department and, apparently, by the mainlaying consultants also. He also wondered why apparently so little attention. had been paid to them by the New Territories Development Department. He thought that there were several contributing factors. Firstly, it was relevant to note the actual details and notes shown in the drawings and the intended use of the drawings by all parties concerned. Secondly, under the provisions of the mainlaying contract the New Territories Development Department had been required to provide a trench over a significant length in which the water- pipe was to be laid. Therefore the New Territories Development Department had known that site conditions would require changes which might affect a future road design. It was therefore a requirement based on good engineering practice to find out what those changes were. Thirdly, the timing of events was significant. It should be noted that not until six months after the watermains were laid was the road upgraded to Category A status and thus the question of planning was relevant. Fourthly, it was relevant to note the standard approach by the Water Supplies Department to mainlaying work, in particular that administered by consultants, which was to do the work at a minimum acceptable cost. 7.121 The Managing Director said that from the information available he had concluded that the failure of the Water Supplies Department to design a pipeline profile was not an omission on its part. The people responsible for the road had effectively carried this out. Further, the Water Supplies Department had no firm data on which to base the design and therefore there had been no need for the Design Division to highlight this aspect to the Construction Division. It had not been necessary for either the Construction Division of the Water Supplies Department or the mainlaying consultants to contact the road authority concerning the profile as it was a straightforward contract. The New Territories Development Department had had all the information to initiate any changes and if the programme had affected normal site procedures, either the Construction Division of the Water Supplies Department or the mainlaying consultants should have been kept informed. When the final design of the road had been executed, somebody should then have found out how the pipe was laid in relation to the other services. The mainlaying consultants felt that at the time the pipeline was laid it was installed as designed, as intended and in a manner that followed good engineering practice.
7.122 The Committee asked whether the mainlaying consultants had established where the final surface was, as the contract specification stipulated that the watermains were to be laid with a cover to final surface of one metre and, if not, how the final surface had been determined. The Managing Director replied that no one had asked that particular question. At the time the mainlaying consultants took over, the Construction Division of the Water Supplies Department had been carrying out the work of laying the pipeline into a trench, which on the drawings had been shown to be 1.8 metres deep.* The depth of 1.8 metres had been determined by the New Territories Development Department and the excavation of the trench had been carried out as part of a drainage contract. It was a normal practice to accept the depth as 1.8 metres below the kerb level. There was no requirement to ask what the final surface meant. The Managing Director contended that if it was crucial to the work, the Construction Division of the Water Supplies Department should have found that out. The Committee commented that, as the mainlaying consultants were supervising the work, they had the responsibility to ascertain where the final surface was before proceeding with the work. 7.123 The Committee asked the Managing Director what he considered the consultants' brief should have been and what their responsibility had been. The Managing Director said that there had been a clause specifically included in their brief to exclude design work during the construction stage. This meant that any factors which influenced the design during the construction stage would be looked after by the Water Supplies Department. The Managing Director did not agree with the Committee that in this case it was the mainlaying consultants' responsibility to seek further information as they had become aware that the roadworks would commence in the near future and that the laying of the watermains could affect the roadworks project.
7.124 The Managing Director said that the pipeline had been laid correctly as intended by the Water Supplies Department, as shown in the mainlaying consultants' documentation and as the New Territories Development Department had expected. The consequences of laying it at that level was a different issue. The Committee pointed out that the watermains had to be re-laid and additional public money had been spent as a result. The Managing Director said that watermains were constantly being re-laid. He explained that when watermains were laid, frequently they had high points and, as a universal practice, they had to be re-laid when future roadworks were actually carried out. The Committee said they could not accept this argument. In this case, it had been known that there was to be a highway. Care should have been taken to ensure that the watermains were laid one metre below the final surface. In the Committee's view this was a basic parameter.
* Note: (In 1978 an arrangement was made between the Water Supplies Department and the New Territories Development Department whereby a trench of 1.8 metres deep was to be excavated in rock areas of the road TY1 to facilitate subsequent mainlaying. The watermains which were laid in such trenches were not the subject of the Director of Audit's observations).
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