HARBOUR BAR

Bay of Plenty Beacon, Volume 9, Issue 70, 6 May 1946, Page 5

HARBOUR BAR

DIFFICULTIES AT LOW WATER A SERIOUS PROBLEM The Whakatane Harbour bar is at present presenting a problem of proportions more serious than it has for the past twentyfive years. During the past two weeks, the coastal shipping trade between Whakatane and Auckland has bfeen severely disrupted through the regular boats being forced to stand off for many hours awaiting sufficient water for them to cross the bar, and if some measures are not taken to counteract the constant shallowness, trade will inevitably be transferred to the rail. This can mean but one thing: the port of Whakatane will become non-ex-istent. Although the entrance channels at the Heads have been steadily growing shallower for some time, the drought, indirectly, appears to have been responsible for their present condition. During the months of dry weather, when the river fell to an exceedingly low level, the sandbank on the left hand side of the river at the Heads gradually extended. When the rain, and a fresh in the river came, it began, just as slowly, to be undermined and carried down, finally being deposited on the bar. During the past few days, when low water on the bar has represented barely 2 feet, it has been possible to see this sand being very slowly moved in a seaward direction.

Suggested Seawall

The only possible way in which the port can be rendered permanently usable, according to the Engineer to the Harbour Board, Mr C. H. Brebner, is to fill the subsidiary channels with rock, thereby diverting the current of water into the one channel. This one "channel would, in this manner be kept clean by the constant scouring of a greater pressure of water. In building such a sea-wall, there lies the danger that the -river, in time of flood, might break through the sand bank beyond the wall, and

proceed to cut a new bed. In order to avoid such a happening, the proposed breakwater, would have to extend some distance into the sandhills, or along the foreshore. It would of necessity have to be built of the best and largest slabs of rock obtainable, such as those at Whale Island. If this quarry Were used, the : stone would have to be lightered across to the mainland.

New Entrance Impracticable To allow the river to cut a new bed, through the sandhills, or, alternatively, to cut one for it, making the harbour entrance lead directly into the ocean away from the tortuous rocks at the Heads, would not be practicable without very heavy ■expense. If this were done, the channel through the sand bank would have to be lined on either side, as if it were not, the set of the current would form a fresh bar sweeping in a wide half circle with the entrance probably somewhere in the vicinity of where the present one is situated. Lining of the sides of such a channel would be an exceedingly expensive operation. Therefore, the only practicable way in which to rectify the present obtaining condition is as stated before, to completely block the subsidiary channels, forcing all water through the one entrance. This itself is a task of no small dimensions, but at the same time, it represents the only way in which the port of Whakatane can be rendered permanently usable.