THE SHANNON BRIDGE.

Manawatu Herald, Volume XLVII, Issue 2898, 18 June 1925, Page 3

THE SHANNON BRIDGE.

PUBLIC WORKS DEPARTMENTS IX DOUBT. At Saturday’s meeting of the Horowhemia County Council, a letter was received from the Public Works Department intimating that they understood the Council was anxious to proceed with the erection of the Shannon Bridge over the Manawatu River and pointing out that, as the bridge was not situated on a Main Highway, the question of allocating the costs to be paid by the various local bodies does not come within the scope of the main Highways Board, and that under the circumstances the best course open to the Council would be to proceed in accordance with Section 119 of the Public Works Act.

He suggested that when the Engineer was designing the new bridge, plans should be in accordance with those of the old bridge. The chairman said that apparently a misunderstanding had arisen over this matter. It appeared that the site of the suggested new bridge was not a dedicated Main Highway and in the bridge was gone on with, the whole cost would have to be met by the local bodies.

Apparently the statements made by the Public Works engineers at Shannon tied not been confirmed. What had been stated at that conference was that the Public Works would not contribute to the cost of repairing the old bridge, but recommended the building of a new one. The Council had gathered front this that the Main Highways Board would be willing to contribute 50 per cent, to this new bridge. The council must be certain on this point, and he would recommend that the County Clerk and himself be authorised to interview the Department regarding their attitude. Agreed.—Chronicle. IXDEPEXDEXT EXGIXEER’S REPORT. (From the Shannon News.) Recently the directors of the Shannon Dairy Co., in co-opera-tion with the Shannon Borough Council, decided to obtain an independent report by a qualified engineeer on the question of repairs to -the bridge over the Manawatu river at Shannon. The Dairy Company have now received the following report from Messrs R. W. Holmes and Son, consulting, civil and mechanical engineers, Wellington : “In considering the question of repairs to the bridge over the Manawatu river at Shannon, it is desirable to bear in mind the importance of the bridge to the town of Shannon. A glance at the map shows that the existing bridge affords ready means of access to a large area of very fertile country, which is known as the Moutoa. and it is on the shortest possible line of road to Foxton, a seaport. The land referred to is served by the two towns, Shannon and Foxton. It is therefore necessary for Shannon to pi’ovide_ the very best inducements for trade to gravitate towards Shannon, and it is in the inof Foxton that as much trade and traffic should pass through that town from and to Shannon in connection with seaborne freight. Consider the position if the bridge be placed further up the river than the present site. The most important point is that the distance from Shannon to .Moutoa will be increased. Further, those who selected the present, site were no doubt actuated b.v this fact. The Drainage Board appears to have carried out works which tend to indicate that the Board lias adopted the present channel of the river as its main drain; whether the River Board is in accord with tbs idea we are not aware, but whatever scheme may eventually be adopted, the flood waters of the river will have to be confined to a well defined channel by stop banks placed sufficiently far apart, and remote from the banks of the low water channel.

The area between the stop banks will require to be free from large obstructions. Consequently any bridges which may be erected will have to he long enough to extend from stop bank to stop bank and must therefore be much longer than the present bridge was. The damage which has occurred to the bridge and the enlargement of the low river channel by the scour of the left bank may at, some future time prove to be of use, providing that the present channel of the river be not departed from. It may be assumed definitely that tlie piesent low river channel is large enough; that it will not require enlarging; that it cannot be maintained any larger and therefore the present banks should be protected from further erosion. “The foregoing arguments tend to show conclusively that: “First. —The present bridge should be restored. “Second. river biuik should be protected from scour. With regards to the bridge, there is only one course to pursue, viz., erect, one span similar to the present ones, strengthen the present end pier, which is in the water way, provide for raising the level of the bridge a few feet, and construct a new graded approach to the left of the Shannon end. The new pier on the left bank, which will be the abutment pier, should be similar to those in the water way as regards the number of piles and general strength, so that without any further cost, it will be suitable to carry another span and also be a permanent pier should further erosion of the river accidentally occur. “The floor of the bridge does not

appear lo be high enough in regard to the water level and also with regard to the stop banks, which have been constructed. Investigations will require to be made to determine a suitable level for the bridge. In time the whole bridge will require raising, but not at present. AYe recommend that the new span be erected at the permanent level, and that the joining end only of Ihe next span be raised. The span being placed on a slope in the meantime. This will keep the immediate expenditure down to a minimum. “The following is an approximate estimate for carrying out the work recommended. It is impossible to prepare an exact estimate from the information available. AYe understand that it is desired at present to avoid incurring the expense of preparing detail plan, etc., therefore we have done the best we can by simple inspection. In any case the estimate will not be exceeded if present conditions continue. 'fhe following is the estimate of repairs to the bridge:— £ Strengthening the present end pier 230 New end pier 400 Additional span ISOO Raising end of present span 120 Forming and gravelling new approach 200 River bank protection 250 Engineering and legal 240 Total £3300