Irrigation was only one factor the Waitaki District Council needed to take into account in the future when it considered issues that contributed to flooding in the district, roading assets manager Michael Voss said yesterday.
Mr Voss presented a report to a council committee last month which said saturation of irrigated farmland intensified the effect of flooding on river flows during four heavy rain events in North Otago at the end of July and in August.
That prompted complaints from some farmers disputing the report, including Duntroon dairy farmer and councillor Geoff Keeling, who said the rural sector was "not enamoured" of the comments.
There had been no irrigation for some months leading up to the heavy rain and it was "a rash statement to make", he told the recent council meeting.
The Otago Daily Times had also been contacted by farmers after it published an article on October 20 based on the report.
One said irrigation on the Waitaki plains stopped in April and the first to start was on September 10, well outside the rainfall events.
Mr Voss, when contacted by the Otago Daily Times for comment, said his report identified issues arising from the flooding which needed to be considered in the future so the roading network could cope better.
Irrigation was one, and referred not to whether water was being applied but the effects on water tables.
However, he also said the council was aware the introduction of mobile irrigators to replace border dykes was having the effect of lowering the water table in some areas, which would lessen the effect of flooding.
There were some instances where irrigation had created localised flooding of roads.
The council had also acknowledged some aspects of its roading network needed improving, including culverts, road widths and roadside drainage.
Last month, it approved spending extra money on improving those areas.
Some recent changes in land use had also resulted in some culverts now being too small or superfluous to requirements.
The use of roads was also changing with land use changes and heavier and faster vehicles.
"What we would appreciate is advanced warning from those involved - either individually or collectively - for us to better prepare the network and better target our investment," he said.
