2023
Download
If you need help accessing these files, visit web accessibility for assistance.
This report is technical in nature and in some cases no alternative description has been provided. Please refer to the Summary Report for high level summary information or email the CEWH Environmental Water Science and Monitoring Section at CEWHscience@dcceew.gov.au if an alternative description is required.
About the report
The summary report outlines environmental watering outcomes in the Murrumbidgee River System during 2021-22. This report is the third for the Murrumbidgee Selected Area under the Flow-MER Program (2019-20 to 2023-24).
The technical report provides detailed methods, analyses, and results with water management recommendations. It also includes two reports from additional monitoring projects:
- Yanco Creek System Technical Report 2021-22; and
- Golden Perch Spawning and Recruitment Dynamics in Floodplain Creeks of the Lowbidgee.
2021-22 Key Environmental Outcomes
Waterbirds
- At least 29 active colonial waterbird sites in the Murrumbidgee Selected Area. This included large (>5,000 nests) ibis and pelican colonies.
- 52 waterbird species recorded including threatened Australasian bittern, and blue-billed and freckled ducks; and international migratory birds including sharp-tailed sandpiper, Caspian terns and common greenshank.
Native fish
- Higher proportions of juvenile native (and exotic) fish were associated with persistent or regularly watered wetlands, indicating regular watering increases opportunities for recruitment.
- Spawning of seven native fish species in the Murrumbidgee River including golden perch, Murray cod and threatened silver perch.
- Eight years of monitoring in the Murrumbidgee River indicates silver perch spawning is not strongly associated with elevated flows.
- High proportion of new Murray cod recruits detected in the Murrumbidgee River suggests high flow conditions support successful recruitment.
- The presence of nine native fish species in the Yanco Creek system, including freshwater catfish, Murray cod and silver perch highlights the ecological value of the anabranches and tributaries within the Yanco Creek System.
Bats, frogs and turtles
- Monitoring of bats in the Yanco Creek system detected 10 native species, including the threatened Southern myotis (fishing bat).
- Abundance of the threatened southern bell frog has been increasing over time at wetlands targeted with water for the environment.
- Detection of Macquarie River turtle for the first time in Gayini Nimmie-Caira are likely due natural flooding throughout the system, however delivery of water for the environment at this site during preceding dry years is likely to have assisted in maintaining habitat and food availability.
Water quality
- Mitigation of low dissolved oxygen water by adding water for the environment in the Lower Murrumbidgee River and Yanco Creek system to protect aquatic animals including native fish.
- Active management of floodplain carbon by repeat watering and flushing flows may have also contributed to the shortened and less intense hypoxic water event in 2021-22 (compared with 2016-17) and should be considered a priority, especially through the North Redbank system.
Vegetation
- Vegetation species richness has increased at Sunshower lagoon (mid-Murrumbidgee) which has received Commonwealth water for the environment for the past three of seven years.
- Vegetation species richness was generally higher in 2021-22 compared with previous years, highlighting the value of flows that achieve overbank conditions within the creeks and channels across Gayini Nimmie-Caira.
Connectivity
- Water for the environment successfully increased lateral connectivity, contributing to foraging and nesting grounds for waterbirds, increasing and maintaining habitat and breeding opportunities for frogs and turtles.
- Water for the environment contributed to opportunities for fish to repopulate wetland habitats and for native fish to move from wetland habitats back to the river.
Read more