The Timaru Herald WEDNESDAY, AUGUST 19, 1908. THE DRAINAGE SYSTEM.

Timaru Herald, Volume XIIC, Issue 13676, 19 August 1908, Page 4

The Timaru Herald WEDNESDAY, AUGUST 19, 1908. THE DRAINAGE SYSTEM.

We'think thaMhere must have been, some misapprehension in the minds of those speakers who stated at the meeting in the South-School last evening that the original scheme for. V the ; underground. drainage system - provided no septic tank at the northern outfall, while it included one for the; southern point of discharge. We are I unable at '.the moment /to say definitely : whether the scheme authorised by the; ratepayers contained the, tank which has been constructed on the Behvenue Cliff, -but we/shall take the earliest oppor, tunity" - of / 'putting' the question beyond dispute: .In the /meantime we must content Yourselves with saying that-we teel almost-'teertain that it-must; have done v so. The last' section of" the Drainage Act is to the effect that at the meeting of .'ratepayers : ,heid- prior "to the, loan /poll,/ "a plan-of the: proposed works,, including; the -position'of 'the outfalls jand form' of'constrjictioWi'thereof, : shall., be The proposal against which last night's meeting- was a protest, is the first suggestion that, 'there should be a, departure from the';plan authorised- by rthe ratepayers,- and -therefore we are of .opinion • that fhe northern septic tank must have been in 'the scheme submitted to , and approved li>y: them. As everyqne knows, that, 'scheine diff eire din several material respects from the Council's original; intentions,) and very possibly Mr Hawkey I and some, of- the others whq spoke last night'iwei'e confusing; the first scheme submitted' to Council by Messrs Meason an& Margharit with the . amended scheme ! actnaily approved by the ratepayers. Thej latter;:, wer think,- must .have.' included a septic'tank'for the north end; the former did "iitot. : In the estimates attached' to their earliest .report, dated May 4th, 1904, the "engineers, allow, for only one septic tank", ?tonbe situated. at the powder magazine. They certainly anticipated the! need for tank—though not at its| present) site—when'[the sewage system shbulaV'be extended into the Waunataifai , Valley/bulivapparehitly they, did not regard it as.;-.ah.. iimmpdiate necessity, while the southern/end wa6 l to come iu at i.once.- '. Perhaps it will be as well to quote an full the paragraph of that original report dealing with sea'. outfalls and.septic -tanks. It reads as follows:

We.propose 'that no sewage whatever shall - into the Bea along the towrTirontage-, but that it shall all be diverted- to the powder magazine at the- south or to the Wahnataitai lagoon at .the north end. We think this-ne-cessary both on grounds ,of sentiment ahd r health. ' The pest of the "diversion would .be/'comparatively speaking inconsiderable. ' All the -higher lying .parts of .the town are capable of having'their sewagedirectly ' ;at one or the other of itne above-named points.

An intercepting'" sewer''-would-be laid along the beach parallel with the railway, line between: .George street, and the, powder magazine on a gradient of 1 in ,700 ito high water :mart. -.jThis -would 'receive the; sewage' from"" the gully" bottoms "bordering. Arthur, Heji/tonV and Queen -streets. A.fo the- pow-der-magazine a'septic; tank would bb {constructed in dimensibn 100 ft. jjy : 50ft. This Vould be of amply sufficient size to receive and liquefy all 1 the 'sewage discharged at this point for .many years to come. An auxiliary tank ;C«.n be ■constructed [beside' it' infuture when a much greater quantity is discharged; flue to increase of population. When ilie sewage' sysfenv'ite' extended into the'sWaimataitai Yalley,, we propose to construct a septic tank near the stone bridge on the Main Road. This would receive and liquefy the .sewage; So thafe„,the effluent from it fibuld be discharged by a pipe laid on the sjighfc this*- point to*' the sea outfall, without any risk of: obstruction taking place in it.... -Without such a; tank, frequent flushingjahd attention Would be necessary to keep tie . discharge pipe from the main-road clear' pf obstruction.. ■■'..■;

Apparently the engineers thought thai iri a completed drainage scheme ..for.Timaru, a northern .septic tank.: wdtuld .-beyneces,sary, not to -protect the- beach - or the; sea ' from pollution, : but as a: safegukrd > against blockage' of the,. pipe ' on . the Jow/ grade between the bridge;pn? ; the main;road;:and :the outfall.- The .scheme : .now,?-pf.icourse, does not: bring .the northern "sewage-down that way- at 'all, and; as far ;as; presenting stoppage : of ; pipes ds ' concerned'^'' the.; septic

tank is of no value whatever, being ab the end of the pipe system. It, must) therefore have been pub where ib is, cither to .render the seAvage innocuous or else, as Mr Hawkey indicated last night, merely as an expensive concession to sentiment. From the fact that the original -scheme provided for a, southern tank before there was any suspicion of obstructive sentiment, and from what Mr Black said last night, we conclude that the northern tank is a salutary precaution, and that it will serve a useful purpose in destroying the sewage and preserving the bay and th<J beach, from pollution. What reason, therefore, is there for dispensing with the ■ tank provided front the very beginning for the south end' It has been admitted that the slight saving which may be effected (£SOO ab the most) is not the commendation of' the change. There has also been some talk of irig.the fall from 1 in 1200 to 1 in boO, but ithere must be some mistake here, because, as is 'shown in the extract we quote, above from the original report of the engineers, the intercepting- sewer falling into the septic tank was to have a. fall of 1 in 700, and in the length betweeh George street and the powder magazine, the difference between 1 in 700 and 1 in 650; ia not worth 'talking about—it is only six inches. Lastly, in an interview which -we published a fortnight ago, Mr Marchant tsaid that the alteration would make the system) equal to all the demands likely to „be made upon it for the , next) 100 years, while the smaller pipes origin-ally-designed might get overworked in l a much shprter time. . In reply to that, it is only "necessary to say that his original scheme, according ,to the report. of May 4th, 1904, "would easily serve an ultimate population of 30,000" (ovet 1 three times what we .have now), and the south' l ■erii tank " would be of amply sufficient size to receive and liquefy all the sewage discharged ab this poinb for many years to .come,", while, another tank .could be added alongside when necessary. Hence we can see no sound reason* beyond the slight saving, for'departing from the original scheme. Mr Marchant is' no doubb quite, right to suggest the saving, at, Mr Black* said lasts night, but if the ratepayers prefer to pay a- little' morel arid have—the best they can be given, their wishes should be considered. ,In the face of their protest, we do not see how! the Council can depart from the schema on. which the loan was authorised.