THE SHANNON BRIDGE.

Manawatu Herald, Volume XLV, Issue 2636, 22 September 1923, Page 3

THE SHANNON BRIDGE.

ENGINEER’S REPORT. The report of the engineers, appointed by a conference of local body delegates, interested in the Shannon bridge has been drawn up and will be submitted to a further conference to he held for the purpose of arriving at a decision on the proposals. ENGINEERS’ PROPOSALS. At the conference of the engineers the following proposals were considered: —(1) To move the bridge down stream a distance of 25 to 30 chains; (2) to lengthen the bridge where it now stands; and (3) to move it up stream to a point, just below the junction of the Mann wain river and the Tokomnru stream. After an exhaustive, enquiry into the efficacy of the three proposals it was decided that No. 1 scheme be rejected. The other two were submitted in the report with a strong recommendation in favour of No. 3 scheme. 'flic latter provides for one long span to be added, and also for three 30 foot spans. In this scheme the road from Foxton to Shannon will he shortened by about half a mile, and it also includes a mile of road construction. This scheme will have valuable results. The cost of No. 2 proposal is estimated at £O,OOO, and that of No. 3 £IO,IOO. It is generally recognised by the local bodies that it is necessary, for obvious reasons —the dangerous condition of the bridge being the most urgent—that an immediate decision should be arrived at, otherwise the arterial road between Foxton and Shannon may be lost for want of a bridge, which experts have ■declared will be swept down stream on the rise of the first big flood. Ti is interesting to note that the eo-t of replacing the present structure, if if were destroyed, is estimated at - £15,000, but as the existing bridge is perfectly sound as regards the timber, used in its construction, the contingency of having to face such an expenditure is to be avoided at all costs by the local bodies.

Erosion is still going on to an nlarming extent, particularly on the western bank, and the engineers are unanimously of the opinion that prompt action is necessary if the bridge is to be saved. CAUSES OF FLOODING.

The idea which many people hold with regard to the flooding of the Munawalu river in believing that it occurs after heavy rains is erroneous, as the following facts gleaned from the report of the Commission of Enquiry into the question of river control, which sat in 1914, would appear to indicate: The river drains an area of 19,030 square miles, equal to 1,235,200 acres. The cause of flooding, the report states, is due largely, if not wholly, to a coincident rainfall on the Tararun and Ruahine ranges, which feed all the tributaries of the river-. An east wind blowing and backing up the .spring tide in Cook Straits blocks the flow of the river at its mouth and checks the flow of the stream, but the tributaries on this side of the ranges, adds the report, have practically no effect on floods.