On Wednesday March 15, 2023, the Murrumbidgee Environmental Water Advisory Group (EWAG) held their 40th meeting at Balranald to discuss the use of water for the environment in the Murrumbidgee Valley.
Water operations update
WaterNSW reported that water in the Murrumbidgee is under normal management operations, and they can deliver all normal river operations. Dam storages across the Murrumbidgee are slightly less than last year, and the target for May is to have an overall storage level capacity of 80%.
Catchment conditions
Weather conditions for the Murrumbidgee are forecast to be average over the coming months. This is after 12 months of above average rainfall and below average temperatures for the region. Inflows to Burrinjuck and Blowering dams and downstream tributaries have all been consistent with rain flow trends over the past 12 months. In the past 12 months, the Murrumbidgee has passed more than twice its total storage capacity. The La Nina weather pattern is weakening, and the weather has returned to normal summer conditions.
Events and monitoring
A total of 85,000 megalitres of water for the environment has been used to maintain appropriate water levels and quality to support waterbird breeding at Gayini, where University of NSW monitoring confirmed just over 100,000 ibises nested during summer. Flows into Wanganella Swamp will cease at the end of March.
The consensus is that it has been a good breeding season for most birds, with increased numbers. A final waterbird report will be available later, with some data still being gathered.
There has been successful management of dissolved oxygen levels downstream of Balranald, Maude and Redbank weirs. At the time of the Environmental Water Advisory Group meeting, there had been no reports of fish deaths in the lower Murrumbidgee during the flood or environmental water recession periods.
Future events
A top up flow for the Western Lakes is planned for April and May to boost habitat for the Southern pygmy perch and create foraging areas for waterbirds during autumn and winter.
The Environmental Water Advisory Group is waiting on confirmation from WaterNSW about maintenance and works to confirm future environmental flow events. Potential works to be done include requests for sites to be dry which could change how environmental water is used. The timing for a 'dry' year is possibly good because of how wet it has been.
Sustainable Diversion Limit Adjustment Mechanism update
A Sustainable Diversion Limit Adjustment Mechanism (SDLAM) program update was given. For the latest updates on projects, please visit the Water website.
Sustainable Diversion Limit Adjustment Mechanism
Field trip
The Environmental Water Advisory Group members gathered on Thursday March 16 for a field trip to Yanga Lake. Nets were set to show Environmental Water Advisory Group members the lake's fish populations. The nets were full of young carp, probably because of the recent flooding. This highlighted the persistent and increasing issue of carp numbers that water managers are facing, especially after flood events.