The Lindis River should remain a functioning ecosystem, Niall Watson insists.
They have had a generation to plan changes to their farming operations, and to find alternatives to running the Lindis dry over summer but they continue to argue for the status quo, or something close to it.
It is true they may have been wrong-footed by the Otago Regional Council's (ORC) suggested 450-litre per second (l/s) minimum flow for the Lindis in the event the Tarras Water Scheme didn't go ahead.
That must have encouraged landholders not to support the Tarras Water Scheme, which is now fully consented but which failed narrowly to get buy-in from local irrigators.
The Resource Management Act, which came into force in October 1991, includes section 413 (3) which states that all historic mining privileges expire on their 30th anniversaries.
The whole point of that law change was to correct Central Otago's lopsided historic water allocation regime - to rebalance the public interest in healthy rivers against the private interest in water for irrigation.
The Lindis is popular for camping, picnicking, swimming and fishing during summer but its amenity values are curtailed when the water runs out.
It supports a range of fish life, mostly trout and upland bullies but also eels and other native fish.
Downstream of the State Highway 8 bridge, where the river becomes more braided in character, it hosts wading birds such as black-billed gulls and black-fronted terns.
From a trout fishery viewpoint it is an important trout spawning and rearing ground that naturally restocks the Clutha River and Lake Dunstan.
At present, in high summer, there is not enough water left in the middle and lower reaches of the Lindis to maintain a healthy aquatic ecosystem because excessive irrigation demand compounds a natural time of stress for aquatic life.
Routinely, as summer progresses the low river level leaves fish exposed to predation and then fish strand in isolated pools with little cover and sub lethal water temperatures.
Surviving fish die quickly if dry conditions continue, either through high water temperatures, low oxygen levels or because pools dry up completely, causing a major loss of aquatic life, most noticeably young trout and native bullies.
The regional council's programme of minimum flow plan changes should restore river flows in Central Otago's over-allocated rivers for the sake of the environment.
The 450l/s minimum flow figure initially suggested for the Lindis is barely a quarter of the natural summer low flow in the Lindis without irrigation takes.
While that achieves the cosmetic effect of getting water to flow to the state highway bridge, the river doesn't connect to the Clutha and it will continue to be a killing zone for fish life, even where a meagre flow remains.
Based on river values and the need to support a functioning ecosystem, something in excess of 50% of the natural low flow is needed.
Many Central Otago irrigators are preparing for 2021 and the expiry of mining privileges.
Catchment groups and collaborative processes have sprung up as irrigators look for alternative sources of supply such as taking from groundwater, taking from under-allocated waters like the Clutha, developing on-farm storage for the harvest of flood flows, joining community based water schemes, or moving to more efficient irrigation techniques but the gains made need to be shared with the environment.
Some irrigators appear to want to move to alternatives and at the same time to hold on to almost all their historic share of summer low flows.
That seems to be the case in the Lindis.
The council has been consulting the Tarras-Lindis Catchment Water Group and statutory interests over minimum flows but they must remember the community is a much broader assemblage than just irrigators and statutory interests like Fish and Game.
This is, after all, a one-in-100-year opportunity to provide for both irrigation and for the environment.
• Niall Watson is Otago Fish and Game Council chief executive
