Covering an area of 81,527 square kilometres, the Murrumbidgee catchment includes 26 storage or diversion structures, along with a 1690-kilometre stretch of the river, and surrounding wetlands.
The Murrumbidgee catchment saw very dry conditions and significantly lower than average inflows in 2019–20. This resulted in only an 11% general security allocation (the average carryover was 8%) with about 30 gigalitres of New South Wales environmental water allowances available for use.
The focus of water managers in 2019–20, with an expected very dry to dry resource availability scenario as identified in the Murrumbidgee Catchment Annual Environmental Watering Priorities 2019–20, was aimed at restoring a more normal flow pattern to support a robust food web and other system functions. These dry conditions continued until early 2020 when wetter than expected conditions occurred.
To build on low starting allocations, water was carried over from the 2018–19 water year. Under these conditions, the Department of Planning, Industry and Environment environmental water managers worked with the Commonwealth Environmental Water Holder (CEWH) to water the Gayini (Nimmie-Caira) wetlands, located in the Lowbidgee region. This private property event inundated thousands of hectares of lignum wetlands and creeks, which in wetter times provide important nesting habitat for colonial waterbirds such as spoonbills and ibis.
Remaining water for the environment was used to maintain refuge habitats for native fish, frogs and turtles as well as habitat important to waterbird species such as Australasian bitterns and brolgas. Significant outcomes included:
- improved condition of wetland vegetation communities in the Lower Murrumbidgee
- improved fish habitat during low flows and heat-wave conditions
- southern bell frog recolonisation
- Australasian bittern breeding (Campbells swamp)
- maintenance of brolga habitat (Tuckerbil and Wanganella swamps)
- some colonial waterbird breeding (Eulimbah, Yarradda, Gooragool).