OUR WATER SUPPLY.

Dominion, Volume 4, Issue 966, 5 November 1910, Page 9

OUR WATER SUPPLY.

DUPLICATION OF THE WAINUI MAIN. BIG SERVICE RESERVOIR IN TOWN. Less than ten years ago the residents of the hill-sides and many of Wellington's smaller suburbs were solely dependent on their tanks for a water supply, and each midsummer was a period of the greatest anxiety, "with " the papers recording -the daily drop in the Karori and Wainui reservoirs. Now we have storage reservoirs that oven supply those resident on the surrounding mountain tops, and another big work about to be undertaken will make our water supply'doubly assured.*; At present the city derives its water from Karori—two basins—and Wainui. ' The former has a restricted watershed, and without other assistance would ba r . little help in a dry summer. Still ..the;: extra basin holds some 60,000,000 gal- _ lons, which would keep "the city going for a month if the need arose. ; This ' city ha? always run a risk in being content with the one" line of cast-iTon-i----pipes from Wainui. There has.'becri serious trouble on half a dozen - ocoaj'y; sions over these pipes,'.-and it is" 0n1y,...! fair to assume that, seeing they have ." been down for twenty ■ years or-more, they aro not quit© so-reliable-as pipes, put in under a. strict tesOorday.-.--S In the winter of 1907 the pipe bridge v carried away, and another- bridge had to be erected, with the river.... in flood ancl generally under the'-infest'' ' difficult conditions. Tiro years ago there was another bad break along the 'Hiitt'--Road, whero cxcavation work was being ; carried on, and there'was a cut off for '. ' several days. 1 During the long summer of a few years ago, that line ">- of old pipes was a Veritable sword of ■*-. Damocles to Wellington. The decision to push on with this important work'-"' stands to the credit of Dr. Newman," .-• who obtained a most valuable' report": ; from the city engineer (Mr. Morton), on which action has since been taken. The New System. _ Mr. Morton showed that the dupliestion was only necessary from the: Wai- " nui Hill—the danger of a serious break' on the other side was not great—and " f anyhow, ft could be repaired in a mini-; ; mum of. time, as the pipe practically " . runs along the surface of the ground'.; from the hill to the basin. ,On. the western (Hutt and city) side there were all manner of contingencies to be taken ; ; into consideration. The new pipe bridge " ; over the Hutt River is "now complete; the widening of the Hutt Road is prac- - tically finished, and there are no serf--:," ous difficulties in the Way of pushing on • : ;"r with the work at once. Mr. Morton;* : has completed tile drafting of the speci- v , fications. They provide for alternative " tenders, of 21 15-16 in. cast-iron pipes, - or Jin. steel pipes, so that the council may have a free hand in selecting-the.'v type of pipe it is advised is the. best'* ■ for the purpose. The new main will '' ■ start from the hill face, .cross the new pipe bridge, como through the Hutt, and along the new main road into the . city,, whence it will be conducted by- ;c the most direct route to a service reser-;' ; voir to be constructed in the hills just' - above the Nairn Street recreation ground. • --

New Service Reservoir. ■. -- i ■ It is a general prinoiple in tho econo-'"'-mics of a water supply, that the watershould not bo conducted direct from :thaoriginal r.eservoir to the taps, that'there should be an intermediate or service ' reservoir to break the direct which we have in Wellington for 'instance. There is nothing new in this—.' it is the accepted tiling in all advanced l cities —Sydney and Melbourne bo'th have : numbers of them. This, servico reser- Y. voir, as stated above/is-to bo erected - on tho Brooklyn Hills, above the Nairn l •: Street. recreation grounds. There a concrete reservoir capable of holding - .2,000,000 gallons will be ■sunk into the. ground at a height-of 380 feet above--. the sea level—a height at which tha.,77 Wainui supply will flow into the'-basin without. mechanical aid.-. With tlila - 2,000,000 gallous and the 1,000,000 gal-:T,: lons. |h'at - would flow through the ne\r ;: -; pipo each day, Wellington would be.; assured of a daily supply of 3,000,000 .-. gallons,-whereas'it at present demands - about 1,000,000 . gallons per day. -The- ; houses above ; the level noted will, - aa now, be supplied from the surface reservoirs, which are supplied from the city;- • 'mains at night by the electricity-driven pumps. Tho fall will be ample.for fir& or any other conceivable purpose. Mr. - ■ Morton hopes later on to lave modern ".. filters fitted to the mains at the proper .■ places, but they ire not. provided for in , the plans for the new' pipe-lino, front.'.'.. Wainui. ..

Now that the plan? and specifications' are prepared, and the money is avail-, able, it will not be long before the work is put in hand. The end of the summen should see it well under weigh. .. ,