LAKE COLERIDGE

Press, Volume LVII, Issue 17103, 26 March 1921, Page 9

LAKE COLERIDGE

HARPER RIVER DIVERSION,

CONSTRUCTION OF PERMANENT WORKS POSTPONED.

A small party, which included Mr A. a. Henderson, president of the Canterbury Progress League, and Mr P. R. Climie, organiser, and which was accompanied by a representative of "The Press/' left Christchurch on Thursday by motor to inspect the works at the diversion of the Harper river into Lake Coleridge. Having heard that trouble had been caused by a blockage at the intako to tho tunnel, necessitating the Tramway Hoard standby electric plant being brought into operation, the party first called at that site, where it was learned that a quantity of weed dislodged by it nnr'-west gale- was responsible for the trouble Stauding on a conereto groin built to protect the intake from tho encroachment of shingle, the party were able to judge how gieat was tho 'shrinkuKe in the lake since the Public Works Department commenced to tap it for power. It is estimated that since that time the level has fallen to the extent of about eight feet. Where there were steepbiuffs or grassy slopes at the water's edgo a few years ago, there is now exposed a shingly beach. About a chain and a* half from tho intake is a bar of shingle in length about, two chains across, which it was possible on Thursday to wade, owing to the shallow depth of water on it. To maintain a sufficient flow of water into the intake it is necessary that channels should bo mado through the bar when it becomes particularly troublesome, which is generally when a nor'-wester is blowing. To obviate the danger of the approach to the intako being obstructed by shingle, the groin on the exposed side is now being extended. When the work is completed, there should, according to experts, be no further causo for alarm in this connexion. Tho party next proceeded to the bed of the Harper river to view tho diversion works. There was a fresh in the river, caused by heavy rains the previous day" in consequence of which it was rushing fast in a turbnlent stream., The Hnrper is constantly changing Its course" in this vicinity. At different it .has- flowed close in beside the hills on

either side of its bed; at present its ' r coarse is somewhere, between the two. A rather frail looking dam diverts the. 'I? water to the course which lends it to the intake of the channel or race, , through which it is brought to the Lake over a distance of about a mile and a quarter. The intake itself is about a quarter of a mile from the dam, which on Tuesday gave way at the far side, but, although a considerable quantity of water was thus escaping, there wasmoro than sufficient to keep the intake supplied at capacity. Closer to the intake, between the top of which and the level of tho water rushing through it, it was just possible to see dnylirht, there waS'another break through. This, hoi' ever, w"as not regarded with any concern, as it was acting in the manner of - a safety valvo to tho intiiko. Tho site of {he proposed permanent diversion is about two_ miles above the intake. Owing, it is understood to the present financial stringency, the Government has decided not to proceed with this work in th© meantime, Quito . recently about thirty 'men were employed in connexion with the diversion works; now there are only nine, which number is necessary for maintenence purposes. Tho contractor, who has recently completed the channel from tho intake to the Lake, has also left during tho past few doy3, taking his plant i' and equipment with him. : All this is j&L considered, regrettable, owin(c> to • the IS difficulty of transporting such plant to |P the jHarperagoinv when it should be P decided to proceed with the permanent *' work, and to the trouble and inconvenience thatwill be experienced in replac ihg tho men just paid off. ~.,'.. The engineer in charge of the wori» stated thai for the past two weeks the quantity of water passing through the intake had been equal to 250 cuaecs. Thursday's fresh, however, had robed this by another fifty cusecs. He considered that in ordinary circumstances there was no'danger of the temporary works proving unequal to the strain to which they were at present being subjected j and that the flow of 250 cusecs would be maintained until such time as-the Government had completed the permanent works, but, of course, a Hood might make a big difference to tko position. When asked to express an opinion on the position, the Progress League's 0% .oials stated that they would have offered no criticism if it had not been that work on the permanent diversion .'■ :; had been postponed. They were sori- ;; ouslsr concerned for the security of Can- '. terbury's industries dependent upon the. ;'; power-station at the Lake; especially i;; in view of the'promise that the third :']:"' pipe line would be connected up by about June. The .coming winter would ';•;''.; impose an unprecedented strain on'the ~ : wjiole.i scheme, and, unless water was ?f; available there would be nq possibility v 6f meeting the demand m the city of I Carfetchurcn, apart altogether from S-: the conntry districts, which have been > promised power at an early date. What they had seen at the Harper Convinced . them that dependence on the. temporary , . diversion was false economy. However 1 seriows the financial situation might be, v the Government was not warranted in ;Running grave risks with the Coleridge j Undertaking. They believed that a . matter 0f..£6000:0r £6OOO would-give a diversion that would be secure against anything but a very abnormal flood. It seemed to .them that theJDepartment was spending about £4O a week, and possibly more, on the maintenance of the temporary diversion, and they could • not understand why a capital expenditure of £SOOO should embarass the Department, whon it wa-j compelled to Bpend so much on mere maintenance. It was absolutely necessary that a continuous supply ot water should be maintained. Tho temporary diversion was a very fine piece 01 work in its way, and they had nothing but admiration for the manner 1 in winch the problem had been handled on this side, but the purpose of the temporary diversion was to Secure the position at the Lake pending the construction of the main works, arid they could not believe that the Department contemplated relying on ■." > the temporary works for any length of time! With such a river as the Harper the diversion work could bo carried on' only when the river was low, and 5 after ■ a heavy fresh jcarae down, the intake to the Luke -race might easily be left 1 high and dry for days together, until . the maintenance gang could repair breaches in .the temporary channel. It v was obvious, too, that at any time a wash-out might carry the stream' to the further side of the river-bed. The. '■'■■■ whole scheme appeared to them to ho a big gamble, and while it was a legitimate gamble, and, indeed, a praiseworthy gamble pending the completion , . of the main divorsion, it was quite another thing to postpono the main work indefinitely. In communications that .'■ had already passed, the Minister had stated that there was, .in his opinion, • no cause for anxiety, but the visit thev had paid to the Harper that day had shown that this opinion was quite misound, ond that there was, in fact, the yery gravest reason for anxiety.