WATER SUPPLY FOR NASEBY.

Mount Ida Chronicle, Volume III, Issue 193, 8 November 1872, Page 6

WATER SUPPLY FOR NASEBY.

Naseby, 14th October, 1872. To John Carrutkers, Esq., Engisteer-ix-Chief, Wellington. Sib, —In accordance with telegram forwarded on the 11th instant, I now have the honor to report upon the scheme of Water Supply from the Manuherikia River, having completed the preliminary survey and levels, with the view of proving the feasibility of the work, and of forming an estimate of the cost of carrying it out. The weather, as I anticipated, and stated in a previous progress report, was un-. suited for survey operations ; yet, as the work was urgent, advantage was vaken of every favorable opportunity to expedite the levels, and obtain what information was required to guide the selection of the channel course. The annexed tracing shows the proposed course of the channel, the various streams met with, and conveys a general idea of the " lie " of the country. In order to have a supply consistent with the requirements of the district, and "in construction, the water will require to be lifted from the Manuherikia at a point not higher up than that marked i as the "Fork" on tracing, which isj shown on the Provincial survey maps to i be 2,600 feet above the level of the sea. j Taking this as a level, which, practi-1 cally, cannot be exceeded, a series of levels j were instituted to ascei*tain the possibility j of securing a more direct route than that of following the contour of the country, : with the due allowance of fall, as shown by the red dotted line. j The results of levels taken of saddle separating the Taieri and Manuherikia' watersheds, and of low saddle between sub-watersheds of north and south i branches of Idaburn (which indicate the ■ only alternative course to that of the red dotted line) prove that a course in this direction, which would have been com-j paratively straight, to be impracticable— | the former being 3,290 feet, and the other ! 2,880 feet above the level of the sea. The j lower saddle alone would necessarily re-' qnire the water to be taken from a height I not less than 3,100 feet, where a compara-1 tively small stream could only be avail-! able, totally inadequate for existing re- j quirements. j

Under the circumstances, and guided by the levels of saddles dividing the Idaburn from the east branch of the Manuherikia, and the Idaburn from Gorge Creek, the only course open for a channel is that shown by the red dotted line, which has the advantage of lifting the water from the Manuherikia, its tributaries, and those of the Taieri met with, at a lower level than existing water races, with one or two exceptions of minor importance. The course having been selected, I guaged the several streams to be met with, and making due allowance for the present excess of flow caused by the melting of the snow, and for loss by absorption, 1 find that the average reliable supply at Naseby will be forty-five Government heads, and the minimum supply in extremely clry seasons not less than twenty-five.

To secure a constant supply at Naseby of say forty Government heads, I would suggest the construction of reservoirs at east branch of Manuherikia, north and south branches of Idabura, and a terminal one in close proximity to Kaseby, from whence supplies for sluicing and flushing purposes can be regulated and distributed. The channel will have an uniform fall of eight feet per mile, with the usual allowance for "breaks" at reservoirs. Guided by a careful examination of the country, its construction will be comparatively inexpensive. The ground is good and favorable, and in no instance, as far

as external appearances indicate, Trill it be liable to slips. There will be very little rock cutting, as tlie level of tli'e race confines its course considerably below the base of the Hawkdim Range. The water will be lifted at a height about 2,560 feet above the level of the sea. The junction with the Manuherikia will, therefore, be about half a mile below the "fork." At Naseby, the level of the proposed distributing reservoir will be about 200 feefc above the junction of proposed main and branch Sludge Channels, and 160 feet above Naseby township. The total length of water channel will not exceed fifty-five miles, and allowing for a flow of forty Government heads, its cost, with the reservoirs and protective works at creek crossings, will be under £20,000. The detail levels and pegging off of channel is progressing, and will be completed in six weeks from present date. I will then be enabled to forward plan, section, and estimate in detail. From the above report it will be evident that the work of introducing the required supply of water into Naseby from the Manuherikia source can be easily, expeditiously, and cheaply accomplished. I have the honor to be, Sir, Your obedient servant, (Signed) P. L. Simpson, C.E.