THE HAURAKI RIVERS.

Hauraki Plains Gazette, Volume XXXIII, Issue 4390, 15 March 1922, Page 4

THE HAURAKI RIVERS.

NAVIGATION AND DRAINAGE, PROBLEMS OF SILTATION. (By Thos. E. McMillan, in the “New Zealand Herald, March 3, 1922.) The greatest adversity, the farm? ers of the Haurakl Plains and the Thames Valley have to contend with is the damage caused by the overflowing of the flood waters of the Waihou and Ohinemuri rivers, which Inundate the low-lying lands for miles around. The watershed of the Ohinemuri is comprised mainly of the hill country in the Waihi district, every flood bringing down thousands of tons of pumice, sand, and mining silt, which are deposited in large quantities on the farm lands, and have a devastating effect on .the vegetation upon which the cattile depasture. The Waihon River watershed is very extensive, reaching to Hamilton in one direction, and almost to Rotorua in another. The problem of so controlling and training this immense volume of surplus water is taxing engineering skill to the utmost, and its solution or otherwise means prosperity or ruin, as the case Slay be, for a large number of landholders, to say nothing of the effects on the commercial life in the various centres in the district. A STUPENDOUS TASK.

It was a. foregone conclusion that a work of such magnitude in a small country like New Zealand could only be undertaken by the State—even if the action of a past Government in proclaiming the Ohinemuri River a sludge channel for mining debris had not forced on this result. For some years the Public Works Department has been engaged in building a system of stop-banks. parallel with both rivers, and designed .to keep the waters confined, to their respective courses. Simultaneously the Lands Drainage Department h'as been carrying out reclamation work bn the Hauraki Plains., and both systems are interwoven, the success of the drainage work depending on the efficiency of the stop-banks and floodgates.. Both are works of unprecedented magnitude in the history of land reclamation in this Dominion, but as the main prize is the famous Hauraki Plains country the cost., even to the tune of £650.»00, has been considered to be warranted. In deference to well-informed opinion., it, is only fair to state that many people consider the work should be accomplished for a much lesser sum. THE OHINEMURI TROUBLE. The Ohinemuri River is particularly obnoxious to the farming community on account of the mining silt it carries down from the goldfields. This silt is not only destructive of vegetation, but it has raised’ the bed of the river from 15ft to 25ft, thus lessening its carrying capacity in times of flood, and causing the river to overflow its banks much more readily than was the case in the premining days. Furthermore, this reduction of draught is proving a serious hindrance to navigation, and has a strangling effect bn the shipping trade with- Auckland. It 1 was scarcely to be expected that in so large a scheme there would not be grave differences of opinion as to the policy to be pursued. The Government scheme is to dam back the flood waters with a system of stopbanks. So far well and good., but toe shipping and local commercial interests in Paeroa and Te Arolia are gravely concerned at the “masterly inactivity” of the Government in respect to navigation. The Ohinemuri Riven is being allowed to silt up at

the rate of Ift per annum, and navigation has to retire further and further as the process goes on. Whereas Waihou River traffic at one time went as far as Matamata, it now has to stop at Te Ar oh a. And the Northern Steamship Company’s boats had to abandon, a few years ago, t,he wharf in the Borough of Paeroa. And now comes the unwelcome intimation that the company will almost immediately be obliged to discontinue bringing its boats to the present wharf, about a mile out of the town, and tp retire to the Public Wprks Department’s wharf at the Puke. This will mean the imposition of 2s or 2s 6d a ton foil wharfage dues and an, increase in cartage rates from the wharf to. the town, and consequently a further handicap against the water-borne trade with Auckland. The state of affairs fast developing should prove to the Government conclusively that its pblicy is upsound. Year by year the Ohinemuri bed is being raised by the successive deposits of silt and pumicepus material, thus lessening the carrying capacity of the river, and at the same time nullifying the effect of the stop-bank-ing. Within 10 years stop-banks of the present height, may be useless, and to raise them substantially would involve enormous expense for actual operations, besides pecessitating the burial of further tracts of some of the most fertile lands in the Dominion for the necessary widening of the base.

DREDGING THE REMEDY. Moreover, the department estimates that it will cost £lO,OOO a year to keep the stop-banks in repair. This sum would cover the cost of keeping two dredges going all the year round. Two dredges would ultimately bring the beds of the rivers down to their original levels, and would so increase their capacities that there would be little danger from floods. With such dredging, combined with a system of low training-.walls, the silt nuisance would be effectively dealt with, navigation interests safeguarded, anl ample fall provided for drainage. There should never be any clash between the interdependent interests of drainage and because both can only be adequately served by the one policy. The Government has intimated that a drainage board will ultimately be formed to take over the river improvement and drainage works, but this is not likely to eventuate until the present scheme is completed. In the meantime, it is, only fair that fully-qualified representatives of the farming., commercial and shipping interests should have a say in the expenditure of public money going on, and a voice in the decision of policy in regard to the major aspects of the river improvement scheme.

AN UNHEEDED PREDICTION. The late Sir George Grey, on the occasion of an historic visit to this district, predicted settlement and progress now taking place. With expansive gesture, pointing to the Haur,aki Plains (then Piako Swamp), he made the prophetic utterance that one day those fertile lowlands would be dotted with prosperous farms and smiling homesteads. Heedless of this prediction the Government of a later and less comprehending, day—a day of men without vision, with eyes that saw not—allowed the Ohinemuri River to be declared a sludge channel. We are now suffering for the sins of out* fathers. And to-day an equally myopic Government is permitting the river to silt up altogether.. Should this disastrous policy be pursued to its logical conclusion the present and future generations will, have tio shoulder a greater burden still.