As Twelve Mile Creek may be a likely water supply option for further development in its catchment, it is important to have a range of information on the waterway, the Otago Regional Council says.
The creek, which flows into Lake Wakatipu 20km from Queenstown on the Glenorchy road, is home to at least two native fish species, the upland bully and the threatened koaro, and is a spawning habitat for brown and rainbow trout.
Council water resource scientist Dean Olsen said in a recent report to its technical committee that although water allocation was very low at present, there was the potential for future development in the area so it was desirable to have information on aquatic ecosystems available to the public to inform them on setting a minimum flow.
Based on in stream habitat modelling, it was suggested a flow of 105 litres per second during December to April would maintain habitat for juvenile and adult trout and koaro while a flow of 120 litres per second would protect trout spawning habitat from May to November.
Cr Michael Deaker said at the meeting the creek was close to totally pristine yet had a lot of recent subdivision nearby and a large camping ground next to it.
Because of this, the impact of the built environment encroaching on the creek and its water quality needed to be taken into account.
Council water scientist Matt Hickey said the council had done one off water quality sampling in the creek, which indicated very good water quality, but had not done intensive monthly monitoring.
Council engineering, hazards and science director Gavin Palmer said a more integrated approach to such water studies had been discussed.
The form of the creek's study was a legacy from past practices and more recent studies were lexamining quality and quantity at the same time.
