Minimum flow level on Hurunui opposed

Press, 18 February 1980, Page 11

Minimum flow level on Hurunui opposed

A minimum flow of eight cumecs for the Hurunui River was opposed when submissions were presented on • the North Canterbury Catchment Board’s draft water allocation plan. Submissions were made by 18 representatives of fisheries, irrigation hydro power, recreation and wildlife interests before a special tribunal chaired bv Dr W. R. Holmes. Tribunal members included the past chairman of the South Canterbury Catchment Board, Mr T. L. Fancourt, and three North Canterbury Catchment Board members, Messrs H. E. Conner, R. F. Stead, and R. D. Gould. The head of the Freshwater Fisheries Division of the Ministry of Agriculture and Fisheries (Dr R. M. McDowell) said migrating salmon and eels would be threatened by the effects of low flows in the Hurunui River. Once flows fell below 16 cumecs, the rivermouth would become partly blocked, water temperatures would rise, and the passage of fish would be delayed by low levels, he said. “The eight-cumec minimum flow is so far beyond . the basic requirements for fisheries that a higher level would have to be set to ensure fish values are not damaged,” said Dr McDowell. The minimum flow proposed by the Fisheries Research Division was 22 cumecs.

The president of the Salmon Anglers’ Association (Mr R. G. Lightfoot) called for a moratorium on. abstraction proposals for the river until the Ministry had completed investigations into salmon farming proposals. The association opposed any irrigation scheme for the area because there was insufficient tinie for the completion of these studies, he said. If abstraction were to take place, the -association recommended a' “buffer dam and reservoir,”' fish screens at intakes, and a “flush” of water down the river during the hours, of darkness. The minimum low flow it suggested for the river was 25 cumecs. The Hurunui Salmon Company (Mr D. H. Xamont) objected to the minimum flow as it would be “detrimental to salmon spawning runs and fi§h life in the river.” The company was planning a hatchery and ocean ranch on the upper-reach-es of the river which had every possibility of becoming a viable industry and. would provide’ more salmon for fishermen, he said;. ...... The amount of water: available to the salmon ; could have a serious- effect on the fishery and; 21 cumecs would alleviate the stress caused to fish by abstraction. The minimum flow at the Mandamus River should be not less than 21

cumecs and 24 cumecs at the rivermouth during irrigation abstraction, said Mr Lamont. A submission by-y- the North Canterbury Acclimatisation Society also opposed the minimum flow set. Its chief executive. officer (Mr B. F. Wel?b) said it would be far too low for the healthy maintenance of the river's ecosystem. The chief soil and water conservator of the Ministry of Works and Development (Mr H. S. Morriss) said the minimum flow should not be fixed as a statutory minimum, but be considered when the plan came' up for review. While the minimum flow of eight cumecs might be a suitable flow in the interim, this figure was arbitrary.The department doubted the validity or need to vary the minimum flow in different months of the ■year. One minimum throughout the year would be appropriate and would simplify management, he said. Mr Morriss also questions the board’s “over-simplification” . of the 50-50 allocation of ? flows above the minimum. A basis more in favour of abstractions would be more reasonable, ■ while ■still having a minimal impact on the river, he said. Th 6 secretary of the Balmoral Irrigation Scheme Committee (Mr O. J. T. Grigg) said the minimum flow figure was too high and seven cusecs' would be sufficient. “If the Balmoral -Irrigation Scheme was to reach its full potential and give its full return to both the nation and the community, irrigators nfust be assured' of sufficient water from the river from September through to April,” he said.. The Electricity Division of the Ministry of Energy and the North Canterbury Electric Power Board presented submissions on

the effect of minimum flow levels on the level of Lake Sumner. A consultant, Mr G. A. Dickens, said it would be premature to set. limits on Lake Sumner levels that differed from the natural levels. “There appears -to be no justification for setting levels until definite and well researched proposals are placed before the Catchment Board,” he said. If such constraints were set it would be prejudicial to the best use of <the water resources. Further studies were desirable on the shore ecology of Lake Sumner, he said. The Commissioner of Crown Lands (Mr E. J. Davies) called for further investigation into the effects of the proposed minimum flow on fish life, the effects of storage or hydro-electric power and the impact on irrigation proposals, and a reconsideration of the basis on which lake level fluctuations were calculated. . Four Canterbury canoe clubs representing more than 300 members made a joint submission on the allocation pliin. The Hurunui River played a central role in -the canoeing scene in Canterbury, being the most scenic, most heavily used, and most diverse river in terms of canoeing opportunity within Canterbury, said Mr P. Johnson,. The submission supported the sharing of flows above a defined minimum, but the four, clubs protested agains-t the low flow minimum. “This flow would render “ much of the river unattractive for- canoeing, ariiiV brings the; river sintoß' < state rarely! achieved nat-U urally,” he said. 1 ' Submissions by the Federated Mountain Clubs and the Canterbury branch of -the Jetboat Association called for-.a flow level on the river that would retain the natural values and opportunities, for recreation.