Little Waimakariri Water For Irrigation

Press, Volume CIX, Issue 32266, 8 April 1970, Page 10

Little Waimakariri Water For Irrigation

Because of the needs for effluent dilution only a limited amount of water would be available for irrigation, Mr H. E. Connor, chairman of the water committee of the North Canterbury Catchment Board, told the irrigation committee of the Water Allocation CounciL ' When the committee met ;the North Canterbury Catchment Board, Mr Connor said: I that there would be some water from the river for irrigation, but they could not say that a quantity like 1100 cusecs would be available. Mr Connor said that they

were confronted with a problem that would appear to demand use of almost all the water at low flow. The chairman of the board, Mr A. T. Bell, said that it did not appear to be appreciated just how low the low flow in the river was—at 1200 to 1400 cusecs it did not allow much margin at all for drawoff. He said that they had bad a request for 3000 cusecs for an irrigation scheme on the north side of the river. As well, there was recreational pressure from the gorge to the mouth and fish and wildlife habitat bad also to be protected, Mr Connor said. In submissions to the irrigation committee, the board said that very high priority should be given to subsidising the treatment of wastes from primary industry and sewerage systems that were at present polluting rivers, streams and lakes. It was more important now to process wastes from freezing works and allied industries, where these now required large river flows for dilution, than it was to take these flows for irrigation. Compounding Problem

Any increase in present stock numbers through irrigation would increase the pollution load from freezing works and add to river pollution from the wastes. Irrigation from the Waimakariri could increase throughput and wastes from the three works at Kaiapoi and Belfast and reduce the river flow for diluting wastes, so compounding the degree of pollution. On the other hand, the satisfactory treatment of industrial wastes could allow

more river water to be released for irrigation. But it might be after the year 2000 before satisfactory treatment of these wastes was achieved, Mr Connor said. The Pollution Advisory Council had been working since 1953. Mr Bell said that he did not think they could come into this at this stage. Classified waters were under the control of the Pollution Advisory Council and they had been told to keep out of this. He also asked what effect there might be in metropolitan areas on the artesian basin if the supply upstream was depleted. When the irrigation committee asked about other irrigation possibilities in the board’s area, Dr W. R. Holmes said that the Rakaia seemed to be a much better proposition and it also did not have the polution dilution problem in the lower reaches. Even the flow in the Rakaia would not meet the demand for two irrigation schemes, said Mr Bell. However Mr M. J. O. Dixon said that the picture might not be so black as far as the Waimakariri was concerned as there would, perhaps, be double the water available in spring for subsurface irrigation.