Upper Cardrona Catchment - Minimum Flows

Background

The Cardrona catchment is situated between Arrowtown and Wanaka, and is located within the upper Clutha River/Mata-au valley. The Crown Range bounds the catchment to the west and south, and the Criffel Range to the east. At the end of the valley, the river crosses about 7 km of relatively flat plains, before meeting with the Clutha River/Mata-au at Albert Town.

The Cardrona River has three distinct reaches, a reach above Mt Barker, a reach between Mt Barker and State Highway 6 and a reach from Stage Highway 6 to the confluence with the Clutha River/Mata-au. Each reach interacts with groundwater in a different way.

Minimum Flows

Dual minimum flows at Mt Barker are proposed for the Upper Cardrona catchment.

Based on the information that is currently available the following draft minimum flows have been suggested:

  • A draft summer minimum flow of 700 litres per second, from 16 November to 15 May.
  • A draft winter minimum flow of 2000 litres per second, from 16 May to 15 November.

This dual approach recognises the need to maintain flow variability across seasons, an important aspect of the natural character of this river.

The summer minimum flow will safeguard the visual appeal and natural characteristics of the river above Mt Barker and will provide for 70 per cent trout habitat retention in this reach.

The winter minimum flow enables flow continuity across the entire main stem of the Cardrona outside of the peak irrigation season in summer.

A draft supplementary minimum flow of 3100 litres per second all year round is also proposed.

Social, economic and cultural reports are yet to be completed for the Upper Cardrona catchment and these will be considered when finalising the proposal.

Background

The Cardrona catchment is situated between Arrowtown and Wanaka, and is located within the upper Clutha River/Mata-au valley. The Crown Range bounds the catchment to the west and south, and the Criffel Range to the east. At the end of the valley, the river crosses about 7 km of relatively flat plains, before meeting with the Clutha River/Mata-au at Albert Town.

The Cardrona River has three distinct reaches, a reach above Mt Barker, a reach between Mt Barker and State Highway 6 and a reach from Stage Highway 6 to the confluence with the Clutha River/Mata-au. Each reach interacts with groundwater in a different way.

Minimum Flows

Dual minimum flows at Mt Barker are proposed for the Upper Cardrona catchment.

Based on the information that is currently available the following draft minimum flows have been suggested:

  • A draft summer minimum flow of 700 litres per second, from 16 November to 15 May.
  • A draft winter minimum flow of 2000 litres per second, from 16 May to 15 November.

This dual approach recognises the need to maintain flow variability across seasons, an important aspect of the natural character of this river.

The summer minimum flow will safeguard the visual appeal and natural characteristics of the river above Mt Barker and will provide for 70 per cent trout habitat retention in this reach.

The winter minimum flow enables flow continuity across the entire main stem of the Cardrona outside of the peak irrigation season in summer.

A draft supplementary minimum flow of 3100 litres per second all year round is also proposed.

Social, economic and cultural reports are yet to be completed for the Upper Cardrona catchment and these will be considered when finalising the proposal.