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In order to accomplish the object which they had in view, the Board resolved to erect a bank at right angles to the general course of the stream, resting on the land and running out into the shingle bed. This was accordingly done, the site chosen being about a quarter of a mile higher up the river than the old Sandy Knolls breastwork. The Board calculated that a bank of shingle would easily sustain any weight of water which might collect above it, and that, as long as it was not overtopped, it would remain unimpaired except perhaps at the extreme end towards the centre of the river, where the water, ponded on the upper side of the bank, was compelled to find its outlet.

The Board was not mistaken as to the difficulty of maintaining the river end of the work. A long low boulder groyne, erected at first, answered the purpose successfully for a considerable time, but was at last washed away; the ground was scoured away from beneath it, and as the materials of which it was composed were merely shingle and boulders, it rapidly disappeared when once the work of destruction had commenced.

The Board have now restored the river end of the work by a structure of timber and shingle combined, for the idea of which they are indebted to Mr. William Goodwin, of the Tai Tapu. The boarded frames of which this is composed are admirably adapted to resist either a scour, an overflow, or the pressure of a very heavy body of water; they terminate in a mass of concrete blocks and bags deeply imbedded in the shingle, and the Board have reason to believe that, in its present shape, the work will prove both effective and durable.

Indeed this bank generally has already been subjected to very heavy tests. The fresh of last May was probably higher than any which has been experienced since February, 1868. That of last July was little inferior to the flood of May; but except at the river end mentioned above the work was wholly uninjured, though the water rose to within one foot of the top of the bank.

Two principal effects are produced by this bank. First, the water being diverted at a low and dangerous point from the south bank, does not return upon it again until it reaches a point well below the ground most liable to overflow, from which the land continues high and safe against danger of encroachment for a considerable distance. Secondly, the ground along the whole line of the Sandy Knolls overflow for a length of about two and a half miles, being thus protected from attack by the river, has been rendered available for cutting, while, at the same time, the land along the river which was being rapidly washed away has been saved from further encroachment.

No change has taken place at the upper embankment since the date of our last report, and this work is, in every respect, in a most satisfactory condition.

The river end of the embankment near Mr. McLean’s has suffered considerably during the last few months; and the work will probably require the careful attention of the Board during the ensuing autumn and winter.

With the exception of certain outworks above the Sandy Knolls river bank, and a small work about half a mile higher up the river, just completed, no other works have been erected by the Board.

In the matter of planting, the Board have used their opportunities to the utmost. By the liberality of Mrs. Deans, of Riccarton, a very large amount of willow cuttings were placed at their disposal, and have been planted, with a very fair measure of success, in front of the three banks protecting the Sandy Knolls overflow, and along the whole line of the river bank at this point, both in the shingle and on the land. The trees and cuttings planted last year have already made a most promising growth, those in the shingle having up to the present time thrown out the strongest shoots.