A new allocation limit for the North Otago volcanic aquifer will eventually be set by the Otago Regional Council, which is likely to increase the amount of groundwater available for irrigation and other uses.
The council held a community workshop at the Kakanui Hall on Tuesday night, at which it outlined the progress it was making to set an allocation limit for the volcanic aquifer, which incorporates the Deborah and Waiareka aquifers.
About 60 people turned out, including those who took water from the aquifer, and Kakanui residents worried about water quality and quantity in the Kakanui River.
Groundwater scientist Jens Rekker outlined the studies that had been done on the aquifer, starting with the North Otago volcanic aquifer study in 2008.
At present, there are resource consents to take up to 6.2 million cubic metres of water a year from the aquifer.
However, research in the past two years had shown that between 1.8 million and 2.2 million cubic metres a year was actually being used, mainly for irrigation.
The actual use in comparison with what was consented was caused by factors including the method the council had used to calculate volumes on takes without water meters.
Farmers at the workshop also pointed out that take was constrained by the type of wells they had, well efficiency, pumps used and water available when the aquifer fell.
Senior policy analyst Karen Sannazzaro outlined the options the council was looking at to set an allocation limit.
The council was also studying the existing restrictions - the level at which water takes were reduced or stopped depending on the level of the aquifer.
Options being explored ranged from an allocation limit of 4 million cubic metres a year to 7 million cubic metres a year.
Depending on community feedback, the council was tending to an allocation somewhere between those figures.
However, some of those at the meeting were worried about the effect on water quality in the aquifer, the quality of the Kakanui River and its estuary, and water quantity in the Kakanui River.
Mr Rekker said the aquifer did not supply water to the Kakanui River, except via the Waiareka Creek.
Kakanui resident Jim Gorman called on the council to take responsibility for cleaning up the river system.
Effluent "poured into the river all over the place", leading to more contaminated water "reaching our estuary".
Oamaru resident Peter Grant blamed that on dairying, which he feared would increase with more extraction from the aquifer.
He said dairying should require publicly notified resource consents.
Cr Doug Brown said the workshop was specifically to discuss the aquifer, but he would take on board issues raised regarding the Kakanui River.
The council will now prepare a draft plan for managing the aquifer, which will be available for public consultation.
After that, it would propose a plan change, which again would be open for public submissions, before a final plan was put in place.
