The process for determining future water management for the Cardrona River catchment will be outlined at a public information day near Wanaka later this month.
The information day, which is open to all users of water in the catchment, will be held from 5.30pm to 7pm on Wednesday March 24 at Mike and Clare Scurr's property on Cardrona Valley Road, 5km from Wanaka.
Otago Regional Council (ORC) staff will outline the process the council will follow when setting a minimum flow regime, which ensures in-stream and community values are preserved.
Council resource scientists have been assessing water resources in the catchment and will present this information at the field day.
Water resource scientist Matthew Dale will explain the process associated with monitoring various tributaries in the Cardrona, with emphasis on natural flows. A natural flow is the volume of water in the river before it is used for irrigation.
Mr Dale will also discuss the instream values that are considered when determining the minimum flow of any river.
ORC groundwater scientist Jens Rekker has been studying the interaction between the river flow and the drainage to ground water.
Mr Rekker will present the information that has been collated to date, highlighting the sites that lose water to the aquifer. This includes a defined section in the lower Cardrona where the drainage to groundwater reserves is more pronounced than in other parts of the river.
ORC land resource officer Bruce Monaghan, who is organizing the information day, said this loss of river flows to groundwater has a significant influence on river flows in the lower reaches and will be an important consideration when assessing the minimum flow levels for the Cardrona."
There are several properties alongside the Cardrona River with deemed permits that take water for irrigation. Deemed permits expire in 2021 and these users will need to reapply to the Otago Regional Council for a resource consent to continue to take water for irrigation needs.
Mr Monaghan says the information day will allow those attending to be informed at an early stage of the technical studies presently being done, but in advance of the formal minimum flow process.
The formal process for determining minimum flows for the Cardrona River will start later this year.