GUIDING THE HUTT

Evening Post, Volume CXI, Issue 103, 4 May 1931, Page 8

GUIDING THE HUTT

IMPORTANT WORK

POINTS TO CONSIDER

(By "Willow-Mat.") The importance of guiding the normal flow of the Hutt Eiver in its upper reaches so that flood waters will be confined to as permanent a course as possible- is so great to the- whole of the Hutt Valley, that it would be a" misfortune to everybody in it if the apparently conflicting interests of the upper and lower valleys were allowed "to result in the subject becoming merely a wrangle, and action, being postponed indefinitely. It is true that Lower Hutt, now approaching the dimensions of a city, is safeguarded by the payments it has made over years, and that the population of the upper valley is not sufficient to pay for the. erection of stop-banks on the same scale. The chairman of the Eiver Board states that it is inadvisable to stop the river spreading over certain low-lying lands, as the spread prevents the damage that would result if an attempt wore made .to confine the river to one channel. There is every reason, however, for those interested to endeavour to secure immediate action -on reasonable linos that would tend to minimise the effects 'of the next flood. Slack water running over farms, and even in residential holdings, does very little-damage, apart from the deposit of silt, not-an unmixed evil. It is the. swift channels which, once opened, tend to become a source of danger, and may even ultimately become the new course of the river: The aim of all preventive work should therefore be first to stop erosion at d«fendable points, and should include groynes designed to keep the river in what is a normal course. It is because of the uncertain effect of- groynes on the opposito bank of the river that the whole of -.this/work , should be placed under the control, if not of one 'body, at least of one- engineer. Nobody knows better than the River Board, which has had to compromise between the rights of people thus affected, the difficulty of determining the exact angle at which wafer deflected from one bank by a big groyne will strike the opposite bank, and it is next to impossible, except for an engineer with a long experience of the river, to plot out the effect of works above on the banks a mile or two down. The uppermost boundary of the Eiver Board at present, .the Silverstream railway bridge, is at a point in the river where the riverbed is naturally confined by hills, and would -make an ideal dividing line for the activities of upper and lower river controls, as, whatever course- the river were made to take above, it would flow into the present Eiver Board's section ,at approximately the same spot. Supposing that an entirely new body, elected by residents above Silverstream as far as Maori Bank, were given control of the upper part of the river, and its activities were restricted to morel}' guiding the course of tho river in tho meantime to prevent the erosion of increasingly valuable property, it would still be advisable that any steps taken should form part of an ultimate scheme to make all but the lowest lying parts of the upper valley as safe as tho lower. To carry this out with any degree of Bntisfaction the work cannot be done piecemeal, nor should private interests be- allowed to interfere with a general scheme. The western banks of the Hutt Eiver are' in some places confined by rocky bluffs and foothills, and where -these conditions exist the general attempt should consist of a throwing back against the western bank of all tendencies on the part of the river to eat into the flats on the eastern side. This could only be planned' by an • engineer closely in touch with his subject. 'It is, however, a work that would lie within reach of the pockets of the comparatively small section of the valley residents affected by the erosion in the upper valley, who could afford to safeguard their holdings by tile engagement of a competent engineer and the expenditure of a few thousand pounds jointly on key groynes. As was pointed out by a correspondent in "The Post" recently, unless something is done to keep the river-over to the west, not only will farm lands suffer, but even the main highways may not remain immune from the toll of the.floods. . Such a body, whose work would- be planned to junction with that of the Hutt Eiver Board, could well be financed by those with threatened interests, and if the river were*.«ajoled as much as possible into a permahent course, with each flood adding silt, to tho portions which aro now , bare shingle, the value of the whole upper valley would be greatly increased. The main groynes would be done by community funds, but there would be nothing to prevent, riverside owners protecting their immediate banks by matting with willows and other minor individual works. It is regrettable, in view of unemployment suid tlie urgency of the matter, that leading citizens in •Ilio up|ier valley do-not take a lend, because the I,'iying of groynes, under proper supervision, would be ..in ideal means to absorb surplus labour.