5

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pletion the Spring Creek River Board (constituted about 1874) obtained an injunction restraining them from proceeding with the work. Obeying the injunction, the Lower Wairau River Board ceased work, and the unfinished work had a worse effect than if no work had been done. In consequence of the injunction the Lower Wairau River Board was compelled to look to stop-banking for protection ; and in the course of time extended their stop-banks on. the right bank practically from near Renwick to Morgan's Creek, and on the left bank from near the railway-line to Dillon's Point. The Omaka River, by reason of its small fall and insufficient channel, had been a constant source of trouble to Blenheim and the lands to the west thereof. The Board therefore diverted this stream into the new Opawa channel one mile below Renwick. They further diverted the Taylor River into the old channel of the Omaka, and built stop-banks on each side where necessary to lead the water safely into the Opawa. Either owing to the increasing quantity of water carried by the Opawa or the occurrence of still higher floods, the banked channels proved inadequate, bursting at several points and doing great damage. The Board then constructed Foster's Channel in an endeavour to provide a straight course for the Opawa River from the bend below the Railway Bridge to the Wairau River north of Section 7, Block XVII, Cloudy Bay Survey District. This scheme, which had been begun without adequate investigation, was a failure. In 1898, on the advice of Mr. Cuthbert, M.1.C.E., what is known as " Rose's overflow " was constructed, and has been of great benefit, carrying off the surplus flood-water. In the meantime the Spring Creek River Board practically ring-fenced the whole of their area with stop-banks where bounded by the Opawa and Wairau Rivers. The effect of these banks, especially along the Opawa, caused a narrowing of the waterways, and a consequent rising of the flood-levels. To cope with this the rival Boards raised their stop-banks. In locating their banks neither Board was guided by engineering principles or practical considerations, the banks being generally placed too close to the rivers in an attempt to save land, and on the sites of the banks constructed by the original settlers. One of the results of this injudicious placing of stop-banks was frequent breach, involving great unnecessary expense. One Board estimates that it spent nearly £20,000 at one breach. Another Board has at one place constructed four different banks along one particular riverfrontage. The Pukaka Stream has its source in the high country between Tuamarina and White's Bay, and by reason of its abrupt fall, is subject to sudden and severe freshets which have no relation to the general flooding of the Wairau. It flows into a swamp, and has no defined channel whereby its waters could reach the Wairau River. About the year 1878 the Pukaka River and. Drainage Board was constituted. This Board constructed works providing a channel to take the waters of the stream by a drain in a fairly direct course from its exit from the hills to the point where the Marakoka Creek enters the Wairau River. Stop-banks were built on each side of the channel, but, unfortunately, were not carried the full length, the consequence being that in time of flood the water, after reaching the end of the completely banked section, spreads over the Native reserve, causing great damage. The Board has not erected any stop-bank on its frontage to the Wairau River. The settlers have built these banks, but without assistance from or supervision by the Board. These banks are, as is the regular practice in the district, built without regard to engineering principles. Recently this Board, owing to the Peninsula banking and the constriction of the channel causing erosion, has found it necessary to carry out some protective works on the Wairau River at Botham's Bend, three-quarters of a mile below the Railway Bridge. In 1912 the Tuamarina River Board was constituted in order to protect a rich stretch of country at the junction of the Tuamarina and Wairau Rivers, which, lying very low, was subject to frequent floods. It has constructed a system of stop-banks which are insufficient to deal, with large floods, but keep the area clear from medium floods. The great flood of last November topped these banks, bursting them in several places, crossed the railway-line, and found its way along the