Evening Post 10 May 1919

WATER SUPPLY

WELLINGTON’S NEEDS

LOOKING AHEAD

Mr. Coleman Phillips has written to the City Council calling its attention to the desirability of extending the Orongorongo supply still further afield, in order to use the Wairarapa Lake itself as an additional supply reservoir for Wellington’s increasing population.

Briefly, Mr. Phillips’ old proposal was first to throw the Orongorongo supply into the Wainui Reservoir (which is about to be done). Then to tunnel out from the Orongorongo River to the Wairongomai Stream; build a reservoir there; harness that stream; and by one electrically driven pumping station fill the Wairongomai Reservoir from the Wairarapa Lake, whenever the necessity arose.

Mr. Morton would not have to waste any fall from Huia Creek to Wainui Reservoir, in order to keep the Orongorongo headworks as low as possible, so as to reduce the lift of water from the Wairarapa Lake to the Wairongomai Reservoir to the minimum—this being the only weakness in the scheme, which Mr. Phillips leaves the engineers to solve with the present powerful pumping plants in use. He referred the council to the one opened by the King some years ago at Chingford for the London water supply.

Now that the Mangahao electric supply station is to be gone on with, the Wairongomai Stream, he points out, could be stored, and drawn upon when required as a help to the Orongorongo supply. There would consequently be a series of reservoirs outwards under this proposal to the eastward:

1. The present one at Wainui
2. At Huia Creek
3. At Wairongomai
4. The Wairarapa Lake itself

Mr. Phillips thinks Mr. Morton should survey this scheme of supply at his convenience, as it would (if practical) be a very simple one, in keeping the Wainui always a full reservoir; and so preserving the one great reticulation service to the city. It would also mean that under it Wellington would never go short of water.

As the survey for deviating the Rimutaka railway via the Wainui route is being proceeded with, this deviation when constructed would, he considers, afford an easy road for keeping all these different reservoirs always under observation.

Mr. Phillips thinks that Wellington, under this ample reservoir proposal, eventually will be the most easily supplied city of the Dominion with an abundant and wholesome supply of water; but provision should at once be made for a city centre of at least a quarter of a million people. (Mr. Morton’s estimate is 198,000 in 25 years’ time). An increased immigration may add to our city’s growth considerably.

He also thinks the council should at once reserve the upper valley of the Whakataki as a water supply, as The Post suggested on Saturday last.

Following is a copy of the letter written to the City Council:—

“I would ask the City Council to excuse my referring to two matters which require a little amendment: (1) Mr. W. H. Morton’s report upon the water supply, and (2) Councillor Norwood’s résumé of the milk position.

“With respect to the first, Mr. Morton says ‘that the suggestion to connect the Orongorongo River with the Wainuiomata waterworks was under consideration during the period that Mr. B. Loughrey was City Engineer.’ As I first made the suggestion when proposing the Rimutaka Deviation via the Wainuiomata some twenty years ago, I think Mr. Morton should have said so; and I would ask him to amend his report to that extent by giving credit where credit is due. It will be found much to the advantage of the city to acknowledge original suggestions for the public benefit.

“My original idea was to sink an 800 ft shaft from the bed of the Orongorongo into the larger of the two proposed tunnels, and pipe the water through to the present reservoirs. But the engineers I consulted considered that some danger might arise to the travelling public, and it would be better to have a separate tunnel for the water.

“Mr. Morton’s report upon the other sources of supply very fairly sums up their different capacities, which we all more or less were acquainted with. But the Orongorongo supply stands out on its own for economy and efficiency. It is because this is so that I should like him to acknowledge the authorship of the suggestion. I think, however, he should have provided for a greater supply than only a 25 years’ increase in population.”