DRAINAGE OF GISBORNE.

Gisborne Times, Volume XXVI, Issue 2098, 27 January 1908, Page 1

DRAINAGE OF GISBORNE.

SUPPLEMENTARY REPORT FROM MR. MESTAYER.

ALTERNATIVE SCHEME SUBMITTED. Mr R. L. Mostayor Ims forwarded the following supplementary report regarding the drainage of Gisborne to tho Borough Council: “Referring to your lot tor of the 16th inst., 1 enclose supplementary estimates for tho reduced schemes, as Requested; also, es-bimaUid tinmiail Cost of pumping for 'tho reduced soli ernes and lor the completed scheme. You •will notice that the salaries of the engincors are higher in. the latter than in the former, as -the general tendency, at the present time is towards increase in everything. I do not think that I have allowed for more than will bo required in this direction, as it will probably be some time before the entire scheme will bo in operation.

AN ALTERNATIVE SCHEME.

“I also submit for your Council’s consideration a suggestion for an alternative scheme, by which tho cost of carrying the sewage to the Wainui outfall could bo postponed tor some years. In this scheme a isept-c tank would bo constructed on the beach about a quarter of a mile. beyond tile breakwater, at tho foot of the ICaiti hills ,as shown on the accompanying tracing. SOME OBJECTIONS. The objections to. .thisVi.u<'.' r estion'' ■aits:— Ist. That when the time comes to carry out the main outfall works, the alternative scheme would be useless and nolle of the work could be utilised for the main outfall work. The pipe.s might, however, be used afterwards for storm water culverts possibly. 2nd. The. attention to be given to tho tank would cost about £‘so per annum. 3rd. Owing to the exposed situation, it would not bo practicable to carry the outfall sewer far .enough into the sea. to ensure none of tho suspended matter being washed up on the beach; this would, however, be minimised by passing tho effluent through a coarse gravel bed by upward filtration, so as to ensure tho removal of all larger solid matter.

THE ADVANTAGES

“On tho other hand, by adopting this as a purely temporary measure, until the population connected to the tank amounted to about 10,000, a saving of about £12,000 could bo effected on the initial cost of tho work, which at 4} pea - cent, would mean a reduction of £540 per annum in interest; or, allowing for extra expense in maintenance and possible contingencies, about‘£4oo to £450 per annum may bo saved; and as the actual cost of the alternative scheme will be about £SOOO, the annual saving in interest would in from 11 to 13 years amount to the total cost of the work. GREAT 1 CARE NECESSARY.

“I cannot say that the proposal appeals very strongly to mo, as the objections are serious; and as the proposed outlet would not be suitable for the complete scheme, all money spent upon, it will ultimately bo so much added to tho total cost, without corresponding benefit to future ratepayers.

“Much also depends upon how long a period will elapse before the population to be served reaches the maxi-

mum of 10,000, which I consider the limit for this alternate scheme. Experience shows that when a town becomes possessed of a first-class water supply and sewerage system, its increase is muesli more rapid than before being so served, and unless the •alternative scheme is available for at least a sufficient period for tho saving in interest to pay for tho work, no advantage whatever—but the reverse —would bo gained by its adoption. Your .Council will bo in a better position than myself to form an opinion as to the time that would probably elapse before the alternative scheme would have to be abandoned in favor of the Wainui outfall proposed in my report.”

ANNUAL COST OF PUMPING.

A. Areas Nos. 1,2. and 3, only—- £ Chief Engineer (and house) 220 Two assistant engineers 340 Fuel (oil, at Is 2d per gallon) 440 Oil, waste, stores, and lighting 150 £llsO B. Areas Nos. 1,2, 3,4, and 10— Chief Engineer (and ho.uso) 220 Two assistant engineers 340 Fuel (oil, at Is 2d per gallon) 580 Oil, waste, stores, and lighting 175 £1315 C. For complete scheme — Chief Engineer (and houso) 250 Two assistant Engineers 375 Occasional extra assistance 100 Fuel (o,il at Is 2d per gallon) 950 Oil, waste, stores, and lighting 300 £1975

I have taken Is 2d as the price of the oil, as this is the price the Wellington Harbor Board is paying for the oil used in its launch; but if it can be obtained at lower rates, (as would probably bo the caso by getting it in large quantities), the cost of fuel would be reduced proportionately. It is possible that the Gisborne oil fields may be found available for this purpose in which case oil might bo obtained at the price named by Mr Hav, of llt cl pea - gallon for crude oil. The cost of pumping is that which will obtain when the population in the respective areas, has reached the maximum; 'at the present time as the population is much below this the expenditure on fuel, stores, etc., will be considerably less.

COST OF VARIOUS SCHEMES.

(Areas Nos. 1,2, and 3.) Outfall sewer 14,700 Total estimate for sewers, ejectors, and chambers, steel and cast iron sewage and air mains, etc . 27,212 Power station and machinery 2,500 £44.412 Engineering, contingencies, etc 10 per cent 4,441 £48,853 —Say £19,000. (Extra for Areas Nos. 4 and 10.) Comprising cost of sewers, eject ors and chambers, additional mains, etc , 19,081 £07,934 —Say £GS.OOO.

If the alternative proposal for a septic tank on the Kaiti beacly is adopted, the amount for areas Nos. 1. 2, and 3 would be reduced to £37,000, and that for areas 1,2, 3,4, and 10 to £56,000. R. L. MESTAYER.