City water down from irrigation

Press, 5 March 1982, Page 2

City water down from irrigation

Difficulties in maintaining the water level in Christchurch City. Council wells could be due partly to the demand for irrigation water west of the city in recent' years; council engineers have suggested. Mr M. J. Bowden, manager of the North Canterbury Catchment Board’s resource investigations division, said yesterday that the effect of such board-approved irrigation wells on the city’s water supply had to be considered in continuing studies. After a works and traffic committee meeting this week, Mr I. F. Crosbie, the city’s waterworks engineer, said that city wells were at the same low level as they had been in 1974, but-it had to be remembered' that the city’s demand for water had gone up nr the meantime. Demand had fallen re-

cently with the odd rain shower and cooler weather. Mr Bowden said that water levels upstream from Christchurch were low, but not as low as they had been in the early 19705. Many irrigation wells had been approved over the last 10 years, and there was a high demand for water from those wells. “That is something we will have to take into consideration in granting rights to take irrigation water,” he said. Water users west of the city had to pump water from the aquifers, but in the “confined area”; under Christchurch, with three or four aquifers under pressure, water rose naturally in the wells. » Mr Bowden; said that the Waimakariri River’s main braid had also shifted north

in the Halketts area, near West Melton, and that could have an effect on the amount of well recharge available in the Christchurch area. That was also being studied. In spite of January being hotter and drier than usual, the amount of City Council water supplied was lower by 278,140 cu m than in January, 1981. Only a third of the average rainfall occurred during January this year. The city supplied 21,888,800 cu m of water from April to the end of January, com-, -pared to 22,192,910 during the same period the previous year. During the 1980-81 financial year, the City Council pumped an average of 74,249 cu m of water a day. The lowest average quantity pumped a day during the six years to that time was 66,470 c m in 1976-77.