Weekly summary of Canty rivers

Press, 28 December 1985, Page 44

Weekly summary of Canty rivers

From today “The Press” will publish each Saturday a summary of the state of flow in the five major rivers of North Canterbury together with week-end predictions. This summary is supplied by Mr D. N. Duffield of the North Canterbury Catchment Board to help anglers, canoeists, jet-boaters and other river-users to judge whether flow conditions will suit their activity. It will also tell irrigators and farmers if flows are high

enough for water abstraction. The first column of the summary gives the river name and the location where the flows are measured. All flows are in cubic metres per second. Midday flows on Sunday and Wednesday of the previous week are listed in the second and third columns to give an idea of the flow trend i.e. whether a river is rising (and becoming discoloured) or falling (and clearing).

The fourth column gives the long-term weekly average for the relevant week of the year to indicate whether the Sunday and Wednesday flows are high or low for the time of year. In the last column, prospects for the week-ena are listed in terms of flow quantity (very low, low, medium, high, flood) and trend (rising, steady, falling). Mr Duffield said that flows in any week are governed mainly by the amount of recent rainfall in the high 4

country. Lack of rainfall leads to decreasing flows. High rainfalls occurring during north-west weather conditions frequently give rise to freshets or floods in all rivers except the Selwyn which has its highest flows during southerly storms. The condition of rivers in River Rakaia: gorge Selwyn: Whitecliffs Waimak: Old h/way br. Hurunui: Mandamus Waiau: Marble Pt ,4

the Canterbury region, as reported by the New Zealand Salmon Anglers’ Association are:—Waiau: dirty; Hurunui: dirty; Ashley. clear, fishable; Waimakariri gorge and mouth: dirty, Rakaia gorge and mouth: dirty, Ashburton: dirty. Week Week-end Sun Wed norm, prospect 467 325 312 high/fall. 2.8 28 2.4 high/fall. 216 256 138 med/fall. 110 • 90 52 med/fall. 515 172 96 med/fall.