Imposing a minimum flow of 900 litres per second for the Lindis River would mean some farmers would be forced off their land, the Environment Court has heard.
That view was expressed by farm consultant acting for the Lindis Catchment Group (LCG) Grant Porter in written evidence to the Environment Court appeal hearing.
And, even with the 550 litres per second minimum flow level sought by the LCG, some farms would struggle, he said.
''Farms that are already carrying significant debt or have significantly less than the modelled capacity to finish stock under spray irrigation, will struggle to remain viable under the 550 litres per second minimum flow plus galleries scenario.''
The galleries scenario is a LCG proposal to replace water races with bores alongside the river.
''Any higher minimum flow [than 550 litres per second] would make the galleries, with their high development costs, non-viable,'' Mr Porter said.
The Otago Fish & Game Council wants the court to uphold the 900 litres per second minimum flow set by the Otago Regional Council (ORC).
Porter said his analysis showed that would result in the present farm systems in the Lindis becoming uneconomic and ''will cause some farmers to have to exit their farms.''