A consequence of a decision on whether an unnamed tributary near Middlemarch is natural or an artificial waterway could ''absurdly'' mean every gully in the country was considered a river, Colin Withnall QC says.
If the court accepted the Otago Regional Council's interpretation, all those gullies would then be subject to the restrictions and provisions on rivers under the Resource Management Act (RMA), he told the High Court at Dunedin yesterday.
A similar concern was also expressed by Justice John Fogarty earlier in the hearing, when he questioned regional council counsel Alastair Logan, during an appeal by Middlemarch farmer John Carruthers against an Environment Court decision which convicted him on two charges under the RMA, relating to the the disturbance of the bed of an unnamed tributary of Lug Creek and 390m of waterway pugged by stock in 2010.
Mr Withnall, counsel for Carruthers, said the issue was whether the watercourse was a river, as defined by the Resource Management Act, or an artificial waterway.
He contended the definition of a river was a continual or intermittent flow of fresh water, excluding artificial water courses.
In this case, the body of water existed only by artificial means, as the water was diverted from Six Mile Creek and conveyed by water races to flow, in part, in a natural waterway.
What the water flowed through, the bed and banks were not an issue. The key was how the water got there, he said.
A key point was that there would be no water in the section below the property's homestead if it was not for the diverted water.
Evidence presented during the earlier hearing was that in a storm or high rainfall event the water would not flow down the waterway, but across it, following the natural fall of the land to nearby Monkey Creek.
However, Mr Withnall contended the RMA provisions covered only flows during normal conditions, not during flood conditions.
The word river had a commonly-accepted meaning and the use of words ''continuously or intermittently'' provided for the separation of the water body from the bed.
If a waterway did not flow enough to sustain natural riparian values, it was not a river, he said.
The interpretation that led to the proposition that anything carrying water after a big storm was a river could not be the interpretation intended by Parliament, because to do so would result in the ''absurd consequence'' of every gully in the country being a river and subject to the RMA, Mr Withnall said.
This was disputed by Mr Logan, who said the RMA used the words ''continuously or intermittently'' to cover all range of conditions from major rivers, which never ran dry, to dry gullies, which flowed only when there was sufficient rain.
The waterway between the farm dam and Ngapuna Rd had the meander pattern and sinuous characteristics of a natural watercourse, as opposed to an artificial one.
He contended any flow of water in a river bed was a river, irrespective of the source of that water, so the artificial watercourse exclusion in the RMA did not apply in the Carruthers case.
''All the races have done is provide water to a pre-existing natural channel.''
While there were artificial features of the stream, they did not deviate in any significant way from the natural flow paths, Mr Logan said.
Justice Fogarty reserved his decision.
