WATER SUPPLY FOR CHRISTCHURCH.

Globe, Volume XX, Issue 1560, 18 February 1879, Page 3

WATER SUPPLY FOR CHRISTCHURCH.

The experimental trial borings at the Wak makar ri in order to test the supp y of water have been so far concluded. These were instituted for the purpose of ascertaining whether there was a sufficient quantity of water underneath the river bed of the Waimakariri at a sufficient depth to cause the water to be thoroughly filtered before it entered the cylinders proposed to be sunk by Mr White’s scheme for supplying Chri-tchurch with water. The trials have not been confined to one place but have been extended to a distance up the river capable of giving the water an elevation of some 40'• feet above the level of Christchurch. This would supply fully sufficient pressure to enable the water thus produced to be used for fire extinction purposes with effect. After eleven trials, which were completed on Friday last, an officer of the works department of the City Council proceeded to test the trial borings, and the following was the result of his investigation: The first boring visited was that opposite McL an’s station. Here a 2in pipe had been driven to a depth of 25ft., the minimum depth at which it is proposed to put down the cylinders. After clearing out tbe pipe, which hid got choked with shingle by some means or other, a good apply was obtained by the aid of a No. 4 American pump, -veraging sixteen gallons per minute, or one gallon per minute more than was obtained at the previous trial, already referred to in our columns. The next boring was on the north side of McLeau’a island, and consisted of a l£in. pipe, driven 25ft. Heiea splendid flow was found of perfectly clear water. The river-side boring, half way up the river, between McLean’s and the head of the island, was by means of a 2in. pipe at 25ft. depth, and here also an excellent flow of pure water was obtained. No. 4 boring is sit..ate 206 chains from No. 3, at the bend of the Island. This is a Uin. pipe at 26ft , cud it gave a very good flow of clear water. No. sis situate 186 chams above the head of the island. H ere there is a 2in. pipe down 25ft., and a capital flow of good water. No. 6 is situate immediately below some protective works of the A aimakariri Conservators, and about seventeen or eighteen miles from Christchurch This is a l.)in. jnpe, at 25ft., yielding a capital flow. Here it see ns feasible is the best site for sinking the cylind r*, as they wou.d h ive the adv ntage of being placed below some extensive protective works, which it is intended to carry still further into the river bed. These protective works, it is believed, will ‘do away with the necessity of placing the mains on piles, as they will in -.11 probability be enabled to be carried direct from the cylinders on to the main land. The ob ject of the water supply committee in having so many tests made is to endeavor to procure for the city such a supply of water as will not only be useful for fire extinction and domestic purposes, but also for the purpose of driving machinery. This is done in Dunedin, and forms a good source of revenue If the same arrangement can be made applicable here, the cost of the water supply will be appreciably reduced by the amount thus recouped. No. 7is above the protective works already refeired to, and opposite the Halfway house, about twenty miles from Christchurch. Here a boring was made to the depth of 21 feet, and was driven through very solid ground, and, after the plug was driven out, no water was obtained. No. 8 boring was made more in the centre of the river bed, and the pipe could only be got down five feet, when it broke, and it was rende.ed useless. No. 9 boring was taken about ten chains further up the river bed to about a depth of twelve feet, when the ground became so hard that driv.ng had to be stoppr-d. he men engaged in boring tried to knock the plug oat, but the pipe had been bent some 3ft. from the bottom, which prevented the rods from going down the pipe. No 10 boring was made some few yards from No 9. The pipe was driven down about 9ft. 6in., and an arlesiaq flow of about 6in. above the level of the water in the river obtained. No. 11, and the list of the trial borings for the present, was taken a fewjards above No 10. Here tbe pipe wag driven to about 12ft., but the ground being so hard no further progress could be made. The object of driving this pipe was to endeavour to get through the hard strata, which, it was thought, might hold a supply of water, which might rise to a considerable height above the river. '! he result of these experiments serins to point to the conclusion that to penetrate these hard strata will require a different kind of boring apparatus to that used in ordinary well boring. It will bo seen from the statement above given of what has b- en done that the water supply c nnmittee have in view the obtaining of a more extended system of water supply than was at first projected, and if they are successful in getting a really good supply of pure water at an elevation of 400 ft, and not more than seventeen or eighteen miles from Christchurch, they will satisfactorily have solved the problem which has so exercised the public mind.