THE RIVER PROTECTION.

Westport Times, Volume III, Issue 433, 19 December 1868, Page 2

THE RIVER PROTECTION.

f ME BLAOkETT'S EiPOET. The following is the conclusion of Mr Blackett's report upon protective works for the banks of the Buller : While on the West Coast I took an opportunity of examining the protective works in progress at Greymouth, and also at Hokitika. The former consists of about 51 chains of wooden breastwork, formed of piles about 32 feet long, driven 6 feet apart, capped, and planked over, about 10 feet down, to the water line ; the whole being strengthened at intervals by land ties and braces. Between this and the edge of the bank, about 30 feet, there exists a triangular space ; the river beach or shore shelving from the street level to a depth of about 23 feet at the line of piles, giving about 13 feet of water on this line. This space it is intended to All up entirely with brushwood, tree tops, branches and logs, without any admixture of earth or gravel ; and it is expected that this will effectually prevent the scour of the river banks, if not at once, gradually, as the mass of brushwood settles down firmly on the bottom.

There is a reasonable hope for the success of this plan, if, as I have been informed, all the piles have been driven to a hard or solid bottom.

The entire cost of the works will be about £6OOO, a like sum having been expended on former protective works, all of which have been carried away. The amount spent in Hokitika in these works, has, I believe, exceeded £40,000. I examined these river works with interest, as being likely to exhibit amongst them some principle which might be favorably adapted to the Buller. In all, however, are points of weakness, even in their present situations, and as they stand, not one of them would resist the action of a single flood in the Buller, in which river the volume of water is immeasurably greater than in the Grey or Hokitika. The use of the timber also, most of it of a very perishable nature, will lead in the course of a very few years to a large outlay for necessary repairs and maintenance.

On this account I should strongly recommend the use of stones and rocks in the formation of permanent protective works wherever practicable. Meanwhile I must point out, in the most forcible manner, the danger to which a great portion of the Eeserve is liable, and the certainty that a considerable amount of damage must ensue, unless some work be undertaken to keep the river in check. It has been suggested that an old barge, or other vessel of sufficient size might be sunk and filled with stones, at a convenient place, to act as a groin or wing-dam. This (were a vessel to be obtained conveniently) would be a ready and comparatively cheap manner of attaining the desired result, if fixed and laid carefully, and at a proper angle. P.S.—Since writing the above, I have received a report as to the character of the spur from which I proposed and expected to have obtained rock. It is reported to be gravelly in places, but with no large boulders ; it is composed mainly of very soft sandstone which may easily be broken up by the fingers. We should, therefore, have to look further for a supply of rock, which mightbe obtained at the foot of the main range, at a distance of about sor 6 miles. This would add to my estimate for a tramway, and make the total, say for 6 miles (instead of 2), £3OOO instead of £IOOO.

Should this tramway be formed, it would be of the greatest service in supplying goods, &c, to the diggers beyond the Orowaiti — such as the Caledonian, Giles Terraces, &c, and its formation might possibly lead to a rapid settlement of the bush land, through which it passed.