The Otago Regional Council will this week consider a proposal to triple the minimum flow of the Manuherikia River in Central Otago over the next 17 years.
The recommendation from council staff is for an initial minimum flow of 900 litres/second at notification but increasing over seven years to 1200 litres p/s by 2030 and finally to 2500 litres p/s by 2040.
These flows would be measured at Alexandra where it joins the Clutha River.
Anna Gillespie, chair of the Manuherikia Catchment Group, said the proposed minimum flows will mean less water for water users. She said the council has not listened to the community.
Council chief executive Richard Saunders acknowledged the move will impact sheep and beef farmers reliant on the river for irrigation, but said the changes will be staged, giving them time to adjust.
Saunders said the proposed 17-year timeframe 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.
“It’s important to note that the Manuherekia River itself needs time to adjust to new flows.
“The science tells us that a significant jump in flows creates its own ecological risks.”
There are 182 surface water take permits within the wider catchment, most related to agriculture.
There are a further 17 groundwater consent takes from the catchment, mostly a mix of consents for agriculture, and two for councils.
Gillespie said she is moderating her response until a final decision is made. She said recent changes in senior management at the council have meant better engagement with the community, but the staff recommendation still ignores their wishes.
They had suggested a minimum flow of 1100l/sec, which would have meant every user lost water, but the proposal was part of a catchment-wide plan to achieve that and manage flows.
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.
At its headwater, the Falls Dam was built in about 1935 and provides some river flow management.