Wellington’s Water Supply
Dams Old and New
An Excursion to Karori
Wellington is a city with a perpetual thirst! Its great, gaping mouth is ever opened wide, and every day of the week and year some 3,200,000 gallons of water are poured down its throat, and that means a daily consumption of seventy-eight gallons a head of the population. It is not suggested that every citizen drinks his seventy-eight gallons a day, but that is the average quantity consumed, and it is used, of course, for divers domestic purposes.
A Progressive Drinker
How to meet this incessant demand has been a problem that has harassed succeeding generations of City Fathers, and it has been responsible for various dams—of a wholly utilitarian nature. The problem was first wrestled with away back in the cobwebbed past, forty years or more ago. Wellington was only an infant city in those days, scarcely out of its long but already it was a heavy and hardened drinker, and to satiate its thirst, the Karori reservoir was built up on the Kaiwarra stream, in-between sloping hills, partly bush-clad.
This served its purpose for a time, but as the years went by, the infant city grew out of juvenility, and its thirst grew deep and manlike. Then came another dam, the Wainui-o-mata dam. This increased the supply by about half. The Karori reservoir has a storage capacity of 46,000,000 gallons; that at Wainui-o-mata being 20,000,000, to which must be added a daily flow or stream of 3,000,000 gallons.
But still the city’s ceaseless thirst was not slaked, and the Council was committed, perforce, to more dams. The first of these is now well under way on the Kaiwarra stream, some fifty-eight and a half chains above the old original reservoir. The new one will be the biggest of the lot, with a capacity of 60,000,000 gallons and a water surface of eight and a half acres. But even this will not be long allowed to hold pride of place. The next work to be undertaken, in the course of a few years, will be the construction of a new reservoir at Wainui-o-mata, with a capacity of 90,000,000 gallons.
Enterprise
What the whole scheme means is best shown by a report drawn up by the City Engineer in November 1904. In it he gives the following estimates:
New storage reservoir at Wainui-o-mata, with concrete dam, waste weir, valve chamber, sluice gate, pipe bridge, roadway, fencing, planting, and contingent works – £40,000.
Extension of existing 30 in. main from existing dam to proposed new reservoir at Wainui-o-mata – £18,800.
Additional reservoir at Karori, with earthen dam, valve tower, waste weir, sluice gate, and contingent works – £20,000.
Venturi meter on Karori main – £400.
Filters on Wainui supply – £9,000.
Filters on Karori supply – £6,000.
New mains in the Wellington ward – £20,000.
Planting Karori catchment area – £200.
Extension to Brooklyn, pumping plant (exclusive of electric cables) and building £1,800; service reservoir (including purchase of ground) £3,500; rising main, reticulation and services £7,000 – £12,300.
Extension to Island Bay, mains, reticulation and services – £5,000.
Extension to Kilbirnie – £7,000.
Extension to Roseneath – £6,500.
Extension to Kelburne – £5,800.
Total cost (exclusive of amount for purchase of Karori catchment area) – £132,000.
New Concrete Reservoir
It will be realised from these figures that water is not so cheap and insignificant as is popularly supposed. Something more than the mere turning of a tap is necessary to bring it forth—strange though this may seem to the casual, unreflecting town-dweller. And if the same casual town-dweller would stretch his stiff, desk-cramped limbs in a stroll as far as the site of the new dam at Karori, and watch the workers at work, he would develop a deep, if sudden, respect for that ubiquitous fluid by the hoboe as something “wet some folks washes in.”
Here one finds a dungareed colony of labour—five-and-sixty sons of genuine physical toil—earning their daily bread, beer and “baccy” by the sweat of their weather-worn brows. Passing the old reservoir, one winds along the light tramway that has been laid, with many a twist, to carry material up the climbing valley, and soon the manly, full-voiced song of work is heard echoing merrily over the hills. The rattle of empty trucks as they dash, with clatter and crash, down the steep line, impatient to be fed again, rises shrilly above the harsh, incessant chorus of the pitiless crusher, as it crunches the heart out of the rock that is poured in a ceaseless flow into its cruel, gaping maw. Engines throb and gurgle in deep content, like good-natured giants glad to be busy, and curling clouds of heavy smoke—Labour’s hard-won incense—float leisurely over the hills to join the mist that rolls in from the sea.
Building the Big Wall
The work is now in full swing, and a cheerful, brawny-limbed toiler of fourteen or fifteen stone, who confesses to being “all that is left” of “the overseer,” predicts that February will see the completion of the undertaking. It is to be a concrete dam, some 74 ft above the level of the stream at its highest point, 325 ft in length, with a thickness of 5 ft at the top, and a maximum width at the bottom of 48 ft.
Rock, sand and cement are the staple articles of diet, and they are being eaten up in vast quantities. An ample supply of blue metal is ready to hand adjoining the site of the work, but the sand has been responsible for a lot of anxiety, as it has to be carted from Island Bay, and 45 yards of it are needed every day. It is worth while watching the crusher in action. Very simple is it in mechanism—just an open mouth with a ridged, revolving tooth of iron.
Hour after hour, and day after day, men with bended backs and naked, toil-grimed arms are shovelling ceaselessly load on load of uneven metal always into the greedy maw of the monster. And it is never glutted or satisfied! Its great jagged fang grinds slowly but resistlessly, without remorse, and it “grinds exceedingly small.” After it has chewed each mouthful, it spits it out, and the masticated metal is washed and graded, then carried down (for the process is a gravitating one) to a lower stage ready for the mixer.
The mixer is an apparatus constructed practically on the principle of the churn, and its function, as is obvious, is to mix the materials that go to the making of the concrete. It is driven by a donkey-engine, and fed with cement, metal, sand, and water. At every mouthful it takes a bag of cement, and a regulated proportion of the other materials, deftly mixed by the brawny chef.
Swung in Mid-Air
Promptly and thoroughly digested in the mixer, the meal is turned out in the shape of a thick, sticky mess, suggestive of boarding-house plum duff. In the next stage it is seen swinging high out into open space, on the ropes of the Flying Fox, then down to the level of the men in the bed of the dam below. Then it is spread over the spaces between the boulders and spawls that have been packed in the inside of the dam, and over all is laid on a solid coating of concrete.
The Flying Fox, in its essentials, consists of an overhead stout wire rope, stationary, firmly anchored in the hillside on each side of the valley, along which cable travels a conveyor, and from it is suspended the truck containing the mixed material. The contrivance remotely suggests Brennan’s mono-rail, only the truck travels under a wire instead of over it. The conveyor is worked by two wire ropes, one of which draws the load out and back along the stationary cable; the other wire raises or lowers it, so that the truck of concrete may be raised to a great altitude or lowered straight down on to the dam site. The motive power is steam.
Down below there is nothing to show what causes the Fox to fly—its wings are hidden. To probe the mystery, it is necessary to clamber up the stinky, steep face of the hill, on to an overlooking terrace, where stands the engine-house in which is caged the unseen motive power.
The Man of Steam
There is a smell of oil in the air, and hot blasts of steam shoot out into the grey chill of the fading afternoon. Inside, a man clothed in blue dungarees and trickling, dirt-grimed sweat, is standing poised at a lever. He is waiting for the signal. All is quiet; there is no throb or beat of pulsing machinery.
Suddenly the staccato warning of an electric bell—operated by the workmen below at the dam site—shakes the stillness, and instantly the place is in an uproar. The engineer is gently moving the harmless-looking little lever, and the wooden shanty shakes and groans as though in the agony of an earthquake, while the engine does its work. In a few moments another shrill, peremptory signal is heard above the storm, and the commotion ceases as suddenly and unexpectedly as it began. The Flying Fox has swung another load through space to the toilers in the depths. And there is humid peace in the engine-house till the signal comes again.
Canvas Homes
Up on this terraced height is a little colony of tents — not the speckless, straight-from-the-store tents beloved of campers-out, who delude themselves into believing they are roughing it, but drab, battered old battlers which might have seen better days, and certainly could not have seen worse. These are the homes of some of the toilers, where they stretch their tired bodies in deep, untroubled sleep after the burden of the day.
Good, hearty fellows that they are, they are not given to dreaming strange, fanciful dreams, or one could imagine them, pillowed on the bosom of the silent hills in the dead black of night, conjuring up the unbelieving shades of the Early Settlers to look on in amazement at the lusty, big-bodied manhood their baby city has grown up to.
No, these tented toilers are more concerned with beefsteak than with spooks or visions. And they have cause to be, for the beefsteak sometimes fails to materialise as obstinately as spooks before an audience of scoffers. There are no macadamised roads from Karori over the hills, and on bad days it is a fair sporting wager whether the expected supplies will arrive or not.
There was a short but severe famine not long ago, owing to the butcher floundering into a slough of despond. But, turning away in the falling twilight, one sees pleasing proof that Labour is not to go hungry to bed this particular evening. A blue-smocked cook is seen pattering about methodically through the open door of the camp kitchen, and over the hills there steals a fragrance that smells sweeter than dew-kissed violets to the workers down below — the fragrance of the evening meal.
