The Otago Regional Council has been seeking feedback from those interested in or affected by proposed changes to the region's water plan.
The council is reviewing minimum water flows in some Otago rivers and streams, and a meeting about the Waianakarua River was held on Monday.
Mr Simpson and his wife, Lyn, who own Olive Grove Lodge and Holiday Park, would have preferred a minimum flow of 0.4 cumecs, (400 litres a second) but accepted 0.3 cumecs.
The ORC's management flow recommendation was for a minimum flow of 0.2 cumecs over the summer irrigation season, rising to 0.4 cumecs over the winter months.
Mr Simpson said he left feeling disappointed and frustrated, as he believed the focus was on irrigation, without regard for the values of the river.
He said he would make a submission and was encouraging others to do the same, but he feared it was too late.
Mr Simpson hoped to get support for the river, saying everyone in North Otago should care about what was happening. It was a "beautiful" river.
When contacted, council policy and planning director Fraser McRae said 32 people attended the meeting.
Other than three who left early, people at the meeting expressed support for what was done there. There was a range of views from people with interests in the river.
The outcome of the meeting will be reported to the council, with the public notification of the plan change in late December.
Anyone could make a submission, and hearings would be held next year, Mr McRae said.
