TOWN BOARD.

Otago Witness, Issue 397, 9 July 1859, Page 6

TOWN BOARD.

This Board met on Monday. Present — Messrs. Dyer, Lambert, Hartley, Kilgour, and Dick ; Dr. Purdie in the chair.

The Clerk read the following communication from the Superintendent's office regarding the levels of the various streets in Dunedin :—: —

" Dunedin, 24th June, 1859,

"Sir, — In reply to your letter of this day, respecting the levels of Dnnedin streets, I am directed by his Honor the Superintendent to inform you that in about a week the whole of the Survey staff will beer ployed taking the gradients of Dunedin ; and when that is done certain levels, applicable to the whole town, will be submitted to the consideialion of the Town Board. Meantime the Board has been furnished with all the information as to gradients which the Government possess, and it is not deemed advisable to recommend the adoption of any particular level for a part of the town, until the whole question can be laid before the Board.

" I have, &c, " John Logan, " Clerk to Superintendent."

The Clerk was instructed to request the Government to furnish the level of Stafford-street as early a3 possible, as the construction of that street was now being proceeded with.

SUITLY OF WATER.

The following report from the Civil Engineer to his Honor the Superintendent, furnished in compliance with the request of the Town Board, as to the best means of supplying the town with water, was read :—: —

" Before entering upon the subject of works for Dunedin, a few preliminary remarks seem called for. The sources from whence water supplies are obtained for towns are rivers, springs, artesian wells, and surface collections. The woik3 necessary for conveying the supplies are modified by the nature of the topography of the district, and the superficial contour of the town and suburbs. Rivers genei ally afford the most ample supplies ; springs and artesian wells seldom afford more than limited quantities; and the power of the stream in this case is for the most part held in requisition to raise the water to the proper level. Surface collections, on the other hand, while affording extensive supplies are frequently available by the force of gravity, unaided by steam power; and, if the area of collection be within a reasonable distance of the town are to be preferred, as the expense of steam power, with wear and tear of machinery, together with the cost of attendance, is avoided.

■ " In determining plans for a town water supply, purity is the most important consideration : generally speaking, the comparative purity of water may be said to stand in the following order :— first, rain water ; second, water from mountain brooks ; third, soil drainage and water from rivers ; and lastly, water from deeply-seated springs or subterraneous sources. The impurities of water are four kinds — mechanical, animal, vegetable, and mineral or saline. The quality of water is of great importance for economical purposes, not to mention the health of man, especially in manufacturing towns, the action of haid water having a perceptible influence in the production of steam and effects in boilers. In breweries, bleaching grounds, washeries, &c, much depends on the quality of water supplied. " The several purposes for which water is required in a town are : — first, ordinary domestic uses, including drinking, washing of persons, clothes, utensils, houses, yards, watering gardens, &c. j second, manufactures ; third, supply of public buildings, baths, wash-houses, &c. ; fourth, extinction of fires ; fifth, cleansing and watering of streets and thoroughfares ; sixth, supplying foun • tains, public gardens, and pleasure grounds. " In piojecting water-works the number of the population is the datum /from whence the calculations are made as to the quanity required. The quantity vaiies in different towns from 30 down to 10 gallons per head per diem — towns possessing trades and manufacturers having greater requirements than others. The quantities supplied by the four leading companies of London are as follows :—: — East London . . 100 gals, per house per diem. New River . . 114 „ „ „ West Middlesex 150 „ „ „ Chelsea 154 „ „ „ This will average 20 to 30 gallons to each individual

" The cost of water supply in London amounts to £3 per individual supplied ; and in the provincial towns of Great Britain the cost varies from the above down to fifteen shillings, according as the difficulties attending the supply are greater or Miialier.

" With the above preliminary remarks, I will now proceed to the subject in hand. The site of Dunedin fronting the harbour, as laid out for occupation, extends two and a half miles in length, and live furlongs in breadth , and its surface rises to an altitude of about 350 feet above the ssa level. Immediately behind the town a ridge runs, whose greatest elevation — Bellevue hill — is 700 feet, and whose lowest depressions are 404 and 378 feet — the former at Balmacuen, the latter at Look-out Point. Rising beyond this ridge, and closing in the' town

site in a westerly and northerly direction, are a range of hills of the following elevations :—: —

Kdikorai 1006 feet Wakari „.. 2096 „ Cargill 2255 „ Signal 1276 „ Out of this ridge immediately behind the town several springs issue, and their waters flow through the town. The three principal of these have been guaged, and their capacity will be noted in Tables A and B hereto appended. From the higher range of hills three streams issut, namely, the North-east Valley stream, the Water of Leith or Wakari, and the Kaikorai, whose capacities also will be noted in Tables A and B. Table A gives the minimum supply, i.e., the supply afforded by the streams in their average low state, without being impounded. Table B gives the maximum supply, i.e., the supply afforded by the streams were all their waters, including flood waters, impouuded and stored up in reservoirs. From these tables it will be seen that the various streams in the town vicinity, without availing of their flood of waters, will serve a population of 165,629 people ; while availing of their flood waters, they will serve a population 01i93,515 —both calculations at thirty gallons per head per diem.

" Regarding the respective quality of the waters of these streams I am not in a position to afford sufficient information, the subject requiring the aid of a chemist to properly investigate ; but if we may judge from common experience, a comparative idea may be formed. All the streams come out of high ridges, and have rapid courses ; their waters may therefore be expected to be little impregnated with mineral matter ; but as all their gathering grounds are more or less covered with forest, except the Kaikorai, they may be expected in several degrees to be tainted with vegetable matter. The Kaikorai, issuing from the bare ridges of the Wakari and Kaikorai hills, may be judged to be the purest and best for the use of the population, and the streamlets from the town belt next to it. The minimum supply of the Kaikorai will be seen to be for 31,1 10,

and its maximum for 95,040 individuals.

" The population of Dunedin being under 2000, and probably more than half that number so scattered and detached as not to be benefuted by water supplies, it is evident that the subject must be considered from two points : — first, in relation to present requirements; and second, in gelation to what may be required in the future. On the latter point it would appear irrelevant to aim at approximate numbers, or supposed times, so much of our increase and prosperity depending on extraneous causes not to be controlled. Considering therefore that Uie streamlets issuing from the town belt afford at minimum'a supply lor upwards of 5000 individuals, and at maximum for upwards of 18,000, at 30 gallons per head per diem— a rate doubly ample for a town such as this without manufactures — it would be from these rivulets close at hand, and distributed equally in the town, that we may derive at least expense, and for many years to come, most advantageously all requisite supply. " Regarding these streamlets it will be proper to remark, that in their courses they do not present favourable basins for the formation of impounding and settling reservoirs. Considering the above circumstance, also that their basins iead into populous or what will be populous parts of (he town, it would not be expedient to embank up waters so immediately overhanging the same— dangerous if accident occur to population and propnrty. All that I would recommend, therefore, wouid be works at a high level for preserving the streamlets in their average low state, and connected with these, main pipes, public stand pipes, &c. With the above views we will be justifi-d in concluding that woiks applied to one of these streamlets will suffice for the present, and that the three will serve the town till it contains a population of 10,000 ; after which the waters of the Kaikorai or Water of Leith might be availed of, — due consideration of which will no doubt be given by the engineer of that future time. " Presuming that all that is now necessary to furnish is such general information as to enable Government to consider the course to be adopted, I will at this tims do no more than indicate the position and extent of the works, together with approximate estimates of costs, leaving the particular works that may be ordered for more detailed consideration hereafter.

[For the purpose of enabling our reader? to understand what follows, it is necessary to mention that the report is accompanied by a plan, on which the characters A, B, and C refar to the points on the larger streams of the Kaikorai, Water of Leith, and N.E. Valley ; and a, b, and c to points on the smaller streamlets in the vicinity of Maclaggan, London, and Regent-streets.] "On leference to the accompanying plan, the positions of the service reservoirs a, b, c, will be noted in the vicinity of London, Maclaggan, and Regent-streeti, from whence the main pipes lead to the principat streets of the town. The course that I would respectfully recommend would be to construct works at a, b, c, respectively as required by the population. In the course of years, when the population has greatly increased, works in like manner might be constructed at A, B, and C, on the larger streams. The elevation of the service reservoirs al a, b, and c, need not exceed 150 to 200 feet, but on the larger an elevation of 500 feet should be adopted; the former would give sufficient pressure by gravitation, for the lower and populated parts of the town, while the latter would do equal service to the higher. " The cost of the works at a, b, c, may be estimated at thirty shillings per head of population to be served ; and those at A, B, and C, when the population to be served exceeds 10,000, at forty shillings. A much higher estimate would require to be given in the latter works for a smaller population. Thus, were it thought desirable to provide for the present population from the town belt streamlets, only estimated at 1000 individuals, the cost would be £1500; for 2000 individuals £3000, and so forth. Prior to works being undertaken, however, it would be necessary to prepare detailed plans and more minute estimates and specifications; but it is to be hoped that the present report will suffice for initiating measures. " J. T. Thomson, C.E. " C. E. Office, June 23, 1859." TABLE A, Showing Minimum Water Supply of Dnnedin from various sources, the data being obtained by guaging the streams in their average unflooded state.

Afer some discussion, it was moved by Mr. Lambert, seconded by Mr. Kilgour, and unanimously agreed to — " That the thanks of the Board are due to his Honor for the report on the best means of supplying Dunedin with water : that the Board coincide with the suggestions of the Civii Engineer as to the general course of procedure ; and respectfully request that at his earliest convenience his Honor will instruct the Civil Engineer to furnish the Board with a more minute estimate of the probable expense of carrying the plan recommended into operation." The upset rent of the municipal sections on Bell Hill was fixed at £8 each. The Board then adjourned.

Name or Stream. .53 "3 O v s> o t» r~. O 0) J3 > Hi 01 . p. . en a CO « tiOTS Maclaggan Street . . London Street Regent Street North-east Valley . . "Water of Leith Knikorai , . . , 4 in. * „ 3 feet i" in. If 21 2| 3| 6? 3f gals. 23243 65599 69997 843556 3033238 933304 774 2186 2333 28118 101108 31110 Totals .. 4968936 165629 TABLE Showing the Maximtt Streams near Dunt face drained and < im Supply edin, the t annual rai >of data infa* Water fro ; being are H. m various Name of Stream. 01-- 2 to a, *!•* S o d « o o Si. Cj > « "g " C B wg o o ■ v o a,P< . a. . cj c to" 0 g-aS gals. I 148500 222750 178200 3326400 8078400 2851200 i I gals. acrs 100 150 120 2240 5440 1920 ' 4950 7425 5940 110880 269280 95040 Maclaggan Street..] London Street .... Regent Street .... North-east Valley.. Water of Leith .... Kaikorai !1485 Totals — .. •• 14805450 493515