THE WAIKATO RIVER.

Pukekohe & Waiuku Times, Volume 3, Issue 239, 16 October 1914, Page 3

THE WAIKATO RIVER.

Deepening the Stream. Board's Work in Progress. On Friday morning last a party of inspection left Mercer by launch at an early hour for the scene of the Waikato River Board's present operations in groyne construction. Those of the party were Messrs A. J. C. Glass, J. Hill, E. Clephane and E. Hallett of the River Board, Mr C. D. Kennedy, the Board's engineer, Messrs Hastie Dean, C. Mardon, J. Oronin and a Times representative. A two hours' run by the Board's fast steam launch brought the party to the Aka Aka channel where one groyno was built last year and another is now in course of construction. JURKOVIXG THE KIVEK. An interesting chat with Mr Kennedy, who is an acknowledged expert in river and drainage engineering, was enjoyed. " The scheme," said Mr Kennedy, "is simple. We must confine the river to within reasonable limits. If that cm be done then Hie river will scour it<elf as the bottom is of a fine pumice deposit which scours very easily." Even a layman, without seeing the river at all, can understand the truth ot this first principle. But a jun down the river it elf proves the statement. Whero the stream is very narrow, as between the bluffs, the water runs 30 feet doep; whero it is seven or eight chains wide the stream is, say, seven feet deep, but where it is twenty chains wide sihd shoals abound and launches can only pick their way ccross it with the utmost difficulty. Both going down and returning the lauutli fouiel «n the shoals jivst below the TuakauOuewhero bridge. This afforded a practical example of the present difficulties of navigation. It demonstrated also that shoals form and the river is shallow where the stream is wide, and the fashion in which the propeller cut huge holes in the river bed and sent great volumes of pumice-sand moving down the river clearly showed how easily a scour may be promoted. THE KIVER LEVELS. "The work upon which we are now engaged," said Mr Kennedy, " affects the conditions between Otatea point and Tauranganui. At low water there is a rise of over 4 feet between those points. The river is very wide and at low water it is practically dry, having no continuous channel. The purpose of tho present work is to drive a channel through this sand-bank and bring the low tide level up to Tauranganui. From the heads to Qtatea, over two miles, at low water there is only a difference of an inch in tho water level, whereas in the next 31 miles there is a four foot fall. If the obstruction which causes this difference in levels were removed then a " fall in tho present high levels must occur." AT TiJi; GBOYNES. The original groyne, at the mouth of the Aka Aka channel, is now a permanent work and behind it a great sand-bank has been formed. On the river side the water is cow soveral feet deep, whereas it was only a few inches when the groyne was first put in. "I am sure we can wipe the dredging out of the scheme," said Mr Kennedy, "and it will mean a saving of £15,000. It is now quite evident that dredging will not be wanted.'' The second groyne is about 20 chains long and a much simpler and less expensive system is being employed. Piles are driven in at regular periods, willows are embedded and interlaced, and the work is then left to Nature to complete itself. The sand forms up at the back and the river, becoming narrower, scours itself and deepens. It is estimated that the groyne now being built will only cost £lO per chain. Our representative expressed anxiety with regard to the Eastern Drain which empties into the Aka Aka channel, but the answer was given that that drain outlet would not be interfered with by the Board's operations. From our representative's position on the river he was unable to form an independent opinion. FIXAXaX'i THE WOKK. To finance the work the Board raised a loan from the A.M.P. Society at 5 per cent interest, plus .1 per cent sinking fund. Half this amount will be available in January next and the second moiety in July. Meanwhile a bank overdraft against the coming loan supplies the financial necessities. River Board ratepayers at present pay Id, .Id and }d, according to their grading. It is intended next year to strike the same rate which, the chairman points out, will cover the loan interest and general expenses. It is now proposed to meet the requirements of Pokeno sub-division from (he general loan. This subdivision agreed to raise £SOO. It is said, however, that only £IOO is needed now and it is suggested by Mr Glass that this should lie financed from the Board's loan money. Tbe party, under the guidance of Mr Glass, spent a most interesting and enjoyable day. The chairman proposes, when tho next groyne is completed, to arrange a general outing in order to give all tho ratepayers an opportunity of seeing the work that is being done.