Prepared for: Commonwealth of Australia, Department of Environment and Energy and concurrently NSW Office of Environment and Heritage
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 WaterNSW to undertake a short-term monitoring project to monitor the hydrology in the lower Macquarie River during the connection flow.
The key observations included:
- Although the peak of the flow event was relatively short in duration and losses were observed during the event, connection was successfully achieved between the Macquarie and Barwon rivers.
- Environmental water in the Macquarie River reached the Barwon River in May during the recession of a significant flow event in the Barwon River during April, with an increase in flow in the Barwon downstream of the Macquarie River confluence.
- The environmental flow from the Macquarie River was evident as approximately 4,000 ML inflow to the Barwon River during May and June.
This monitoring provides valuable information on the flows required to provide connectivity between the lower Macquarie and Barwon rivers, and will help inform future watering actions and management decisions in the Macquarie catchment.
Photo: Lower Macquarie showing temporary gauging station installed by WaterNSW Credit: CEWO
Photo: Temporary gauging station installed by WaterNSW on the lower Macquarie River. Credit: CEWO