'Voluntary' irrigation limit proposed to help ailing river

The Selwyn River has recorded record low flows in recent months. Photo / Richard Cosgrove

A collaborative approach relying on voluntary action by farmers has been recommended as a way to limit irrigation in the catchment of the ailing Selwyn/Waikirikiri River.

The river recorded record low flows over summer, although recent rain has temporarily covered some dry stretches.

The Selwyn Waihora Zone Committee has recommended that Environment Canterbury work with land owners and the farming industry on potential voluntary restrictions and other on farm actions.

It opted not to push for either of the two more forceful options proposed last month - a water shortage direction imposing a short term but immediate restriction on 65 consent holders in the catchment area, or reviewing those consents which would enable consideration of whether they should be revoked or altered. A consent review would be expected to take three to five years.

A report to the zone committee, presented by ECan's science director Stefanie Rixecker and chief operating officer Don Rule, stated that the water shortage direction would achieve only a minimal improvement, if any, to flows and would have the most impact if it was put in place in spring.

"It may increase chances for sustained flow at Coes Ford, and it could potentially make the difference between very low flow and no flow. The benefit in flow could be in the order of 100 litres per second," the report said.

Legal advice to ECan focused on whether a water shortage direction would meet statutory requirements, in particular whether there was currently a serious, temporary shortage of water. The advice was that while there was a serious shortage of water, it was unclear whether the situation was temporary and this could be challenged in court.

The report said that previous consent reviews had, on average, cost ECan $1800 per consent. The figure would be expected to be lower than that if pursued for the Selwyn River catchment but would also cost the consent holders themselves money. A consent review could also be open to legal challenge.

North Canterbury Fish and Game general manager and ECan councillor Rod Cullinane said the recommended option was only fiddling with the issue rather than addressing the root cause - but the other two options were no better.

"The horse has well and truly bolted on this one, the region is severely over-allocated," Mr Cullinane said.

"In the long term the solution has to be a reduction in the amount of abstraction, and how that is done is a challenge."

ECan has said consecutive drought years is the major cause of low flows in the river, with irrigation a contributing factor.