The Otago Regional Council is consulting on a proposal to set a 3600-litre/second minimum flow for the river in summer and 7000lps flow in the winter.
It also proposes a primary allocation limit of 1000lps and a supplementary flow allocation of 500lps.
Council senior policy analyst Richard Pettinger said in a report to a recent policy committee meeting the proposed Plan Change 3B would manage the Pomahaka catchment by protecting fish and aquatic life while providing consent holders with a ''reasonable reliability of supply''.
''Changing land use with the catchment has resulted in increasing demand for water for out-of-stream uses, principally irrigation.''
When water takes increase, pressure is put on aquatic ecosystems and other river values and river flows may be reduced more quickly and frequently.
In the past four years the council had held workshops with land users, the community, iwi, Federated Farmers, Department of Conservation and New Zealand Landcare to talk about the issues.
Council chairman Stephen Woodhead said the community had very strong views about implementing as high a minimum flow as possible.
''We've had good robust discussions with the community.''
Cr Michael Deaker said the flows and allocation limits were based on technical reports done in 2006, but in that time the Pomahaka catchment had undergone many changes, including increasing water takes and intensification of agriculture.
''A lot has changed in West Otago.''
Council policy and planning director Fraser McRae said the values identified in those reports had not changed and had been reinforced by the community workshops.
While there was a lot of water in the river, there was the belief in the community there could be ''a big demand coming in for water, so we need to get on to the numbers'', he said.
The proposed limits met the present demand but would not allow anyone else to apply for a primary allocation.
''They will have to come in as a supplementary allocation.''
Supplementary allocations were subject to higher minimum flows so their allocation stopped much sooner than with primary allocation takes.
Supplementary allocation was typically used in winter and spring, when river flows were much higher.
The consultation will be used to prepare the plan change for public notification in August.
