The current and future changes in land use would lead to further deterioration in the quality of water in the Taieri River and adversely affect sports fishery values, Otago Fish and Game Council environmental officer John Hollows told a meeting in Cromwell yesterday.
"This occurrence might be a blueprint of what is to come in the Manuherikia River, given the recent development in the catchment," Mr Hollows said.
His report to the council on issues surrounding dairy expansion in the Maniototo made for "scary reading", council chairman John Barlow said.
Council chief executive Niall Watson said the issues were complex and had an impact on the quality and quantity of water.
Mr Hollows said the Maniototo area of the Taieri River had undergone a dramatic transformation from traditional dryland farming to more intensive agriculture.
Some had bought properties with mining rights and used those previously unused or underused permits to take water.
He outlined details of five expansions or conversions to dairy farms in the Maniototo and said district and regional plans allowed for dairy expansion in that area despite the adverse impact of intensive farming on waterways.
The council agreed to ask the Otago Regional Council to carry out water quality monitoring in drains, tributaries and other main sites to measure the impact on the wetland and the river.
It will be asking the regional council about the claw-back provisions of the regional water plan, covering when unused water is required to be surrendered.
As well, it will carry out aerial monitoring on the wetlands in the area to detect any encroachment and development of that area.
