Making the Connection: Designing, delivering and monitoring flows between catchments

2017
Davis, S., Asmus, M.W and Stocks, J.R.

A case study in the Macquarie and Barwon Rivers April – June 2017

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About the document

In autumn 2017, an opportunity was identified to support native fish in the lower Macquarie and Barwon rivers. This opportunity resulted from golden perch spawning in the Barwon River in spring 2016, and a natural flow pulse moving down the Barwon River.

Between April and May 2017, Commonwealth environmental water (27,583 ML) was delivered to the lower Macquarie River, via the Macquarie Marshes, to connect the Macquarie and Barwon rivers. This flow was designed to facilitate the movement of native fish between the two river systems, and provide opportunities for juvenile native fish such as golden perch, spangled perch and silver perch (critically endangered under EPBC Act) to migrate into the Macquarie catchment.

The Commonwealth Environmental Water Office contracted the NSW Department of Primary Industries – Fisheries to undertake a short-term monitoring project to assess the response of native fish in the lower Macquarie River to the connection flow.

The key observations included:

  • Connectivity between the lower Macquarie and Barwon rivers can be successfully achieved using environmental water, particularly in synchrony with flow events occurring in the Barwon River.
  • Movement of native fish species, particularly golden perch and spangled perch was facilitated by the environmental flow and connection between the Macquarie and Barwon rivers.
  • Hyrtl’s tandan, a medium bodied river channel specialist more commonly found in the Paroo/Barwon/Darling River system, were detected at the most downstream site, representing the first capture of the species by DPI Fisheries in the Macquarie River.
  • The project highlights the significance of a good working relationship between managers, water holders and scientific agencies.

This monitoring provides valuable information on fish response to environmental water in the lower Macquarie, and will help inform future watering actions and management decisions to support connectivity between the Macquarie and Barwon river systems. 

Photo: Junction of the lower Macquarie River and Barwon River during the connection flow. Credit: CEWO