NEW WATER PROPOSAL

Evening Post, Volume XCIX, Issue 69, 22 March 1920, Page 6

NEW WATER PROPOSAL

The City Engineer (Mr W. H. Morton) has made an important -alteration in his water supply recommendationsIt should be explained that, excluding the. overworked Rarori (or Kaiwarra) Stream, there are at least five possible sources of water supply : (ij The Wai-riui-o-Mata, which cannot be further exploited except by the erection of a third storage reservoir; (£) the Orongorongo, ■\Vhich runs parallel with the Wainui-6-Mata; (3) the Hutt River, near its junction with the Pakuratah); (4) the Hutt tributary Little' Akatarawu; (5) the Hutt tributary Whakatiki. In the City Engineer's report last year only one of these schemes' (No. 3) was.mentioned as having altitude enough to gri> viiAto Into tHA Kiwori high-l£Ve,l iititvoir, There are) of coui'te, obvioui ad-

vantages in an auxiliary supply being available for., high-level purposes, and* this fact at once put the Hutt proposition on something of a pedestal. But tho utilisation of the Hutt Basin waters —Hutt, the two Akatarawas, and Whakatiki—is in part dependent on cooperation between the city and the Hutt Valley, for geographically and economically the Valley population hn« first call ; and as the local bodies of the Wellington district are too proud to co-operate, or too Belf-sufficient, or too stupid, a partnership scheme for dealing with the Hutt and its tributaries makes no headWay. Consequently the City Engineer last year recommended the City Council -to confine its water supply extension proposals to tho Wainui-o-Mata and Orongoronjfo. Meanwhile the alienation and deforestation of tho Akatarawas and the Whakatiki continue; and in a fovc yoars the local bodies will hayo to pay much more for a damaged asset than they might recently- have paid for bnspoiled forest land. But that is by tho way. The new element now introduced by the City Engineer is a proposal to utilise the Ofongorongo not merely for diversion into the Wainui-o-Mati reservoirs—as suggested las* ye-ir—but as an independent supply gravitating into tho Karori reservoir. It now • appears that the fch'ongorongo, can be reached by tunnel at a point where it has a volume arid an altitude sufficient for the diversion of three million gallons per day to Karori, which will thus become, as a ier.vice refeervoir, very much mote important than in its dependence on present inadequate local supplies. What has happened is that, in place of diverting the Oi-oiigorongo tOj the Wainui-o-Mata and adding to the Jatter's storage, the Engineer now offers a direct high-level service from the Orongorongo, whioh; it is understood, will enable; the projected ,_^Wainui storage reservoir (capacity eight hundred million gallons) to be postponed. For the new plan two tunnels are required—one leading from the Ordhgorongai into the Wainui-o-Mata, estimated to cost £80,000; the other hading from the Wainui-o-Mata into the Waiwetu, estimated to cost £18,000. When the diverted water issues from the first; tunnel, it will enter a new special 21in main, which will be 'iconstructed of metal of unusual thickness" to meet "the unusually high pressures to which it will be subjected." This main, 1379 chains long, ia estimated to cost £208,575; and, with contingencies added, the. whole estimate is £337,232. Last year's scheme was estimated at £540,650, but it included £120,000 for the eight hundred 1 million gallon dam and £198,000 for a. new 30-inclT main in the city. Whether the latter is to be postponed, or is still to be deemed urgent, is not clear. - <