Farmers relying on irrigation from the Manuherikia River in Central Otago fear new higher minimum flow rates will leave them with unusable assets and few choices for their land.
The Otago Regional Council this week accepted a staff recommendation to triple the river’s minimum flow to 2500 litres per second over the next 17 years.
The recommendation is for an initial minimum flow of 900 l/s on notification – increasing over seven years to 1200 l/s by 2030 and finally to 2500 l/s by 2040.
This will be measured at Alexandra, at the bottom of the catchment, and councillors and staff acknowledge it will impact farmers and land use.
Council chief executive Richard Saunders said the proposed 17-year time frame is driven by the potential scale of change required in the catchment, the expiry dates of existing resource consents and the need to appropriately manage higher flows within the river.
The former chair of the Manuherikia Catchment Group, Anna Gillespie, said the decision ignores an offer by land users to implement a catchment-wide scheme to provide a minimum flow of 1100l/s.
Land-use change is not an option for many of the affected farmers.
The scale of on-farm storage needed to be reliable is prohibitive, the valley is too high and too cold for grapes or horticulture and most farms are too small to become dryland businesses.
Gillespie’s farm has about $2 million invested in irrigation infrastructure that could become surplus in 2040.
She said their hope is that the 90-year-old Falls Dam at the head of the catchment can be rebuilt to supply water for the river and irrigation.
There are 182 surface water take permits within the wider catchment, most related to agriculture, and 17 groundwater consents for agriculture and two for councils.
The Manuherikia River catchment originates in the northern reaches of the Maniototo district, the St Bathans and Hawkdun ranges.
It then flows 85km to join the Clutha River at Alexandra.