WANGANUI HARBOUR Comment On Recent Report By The Engineer

Wanganui Chronicle, 27 April 1950, Page 4

WANGANUI HARBOUR Comment On Recent Report By The Engineer

“Wanganui City, once the fifth city in New Zealand,, is now about the tenth city, it is a disturbing thought," writes Mr. T. G. Mullins, in a letter to the “Chronicle'’ about harbour matters.

“The depreciated harbour is also disturbing. The recently published report of the Wanganui Harbour Board’s registered civil engineer contains disturbing opinion, in that the board has no alternative but to adopt a dredging policy. It is this dredging policy that has crippled, financially, the past boards and rendered them impotent to carry on any activity in th* way of improvements, and even they have resorted to the neglect of maintenance to try and balance the budget. This neglect has further reduced revenue. It is a vicious cycle that will ever turn increasingly downwards. “The heading referring to the types of vessels using the port is also disturbing. Does the engineer know' that at one time 8000-ton vessels berthed at Castlecliff’ Does he mean that we are never again to see these vessels here? What a poor outlook for Wanganui!

“(1) His estimate of £3OOO to keep the port dredged is about one-tenth correct. Upon this figure he has based his comparisons. “(2) His statement that the sand overlaying the mud in the basin came through the breach in the basin wall is incorrect. This sand (and underneath metal) was pumped there by the Kaione. When the small breach in the south wall of the basin was deepened about 2ft. in 1946, to 2ft. to 3ft. of the top layer of soft mud went out of the basin. If this breach is blocked up this silting will return. Today more of the old punt by the dolphin can be seen and the dividing wall stands out 2ft. more than it did In 1945.

“(3) His statement that part of the river flowing through the basin would render the estuary hydraulically unstable is misleading. The present condition renders the estuary dydraulically unstable as anybody could reason, because of the great amount of dredging required. When a stream of the river did flow around this path, during the time between the start of building the north mole and the building of the basin wall, there was 17ft. of water along the berths (with no dred ting).

"(4) The statement comparing ebb and flood tides needs much more investigating than apparently made. Although one may see the ebb flowing longer than the flood, one must realise that the flood is flowing in along the bottom long before the top layers of water cease flowing out, and it is the bottom layer of water that does the scouring. The strength of the inflow is shown by the fact of the presence of the inner channel. A study of this channel will prove to any thinking person that it is made by the inflowing tide, the direction of which is largely governed by the north mole. “Mr. Clay's statement regarding the deterioration of No. 1 wharf berths caused by building up the end of the south mole in 1938, is correct. This raising of the mole altered the direction of the incoming tide—not the outgoing tide. This altered current caused oeep water in the middle of the estuary (near the notorious groyne) and. allowed greater siltation at No. 1 wharf. As Mr Clay apparently understands this, I am surprised at him saying that the inflow, or flood tide, is feeble. I am also surprised that Mr. Clay, knowing that the raising of the south mole caused the deterioration of the depths at No. 1 wharf, still spends money on the notorious groyne. Of course some of us know that Mr. Clay is in the unhappy position ot having to do what he is told.

“It would be better for Mr. Clay to concentrate his practical activities on repair jobs to the buildings, especially the cool store, and then he will have more time to make a thorough study of the harbour before proposing any constructions in the harbour estuary.”