The Macquarie Cudgegong Environmental Water Advisory Group (EWAG) met in Mudgee to discuss environmental water use to date and review the outcomes against the objectives set for this year. In preparation, the Macquarie Cudgegong EWAG toured the regulated Cudgegong River the day before and met with community members to discuss the current watering event.
Catchment conditions
Conditions across the catchment are dry, with lower than average rainfall recorded in September. Soil moisture is also below average.
The Bureau of Meteorology forecasts average rainfall but hot conditions for November to January, with median maximum temperatures likely to be exceeded.
At the time of the meeting, Burrendong Dam was at 82% capacity while Windamere Dam was at 95%.
Cudgegong River field trip
EWAG members visited Windamere Dam on the Cudgegong River, 30 km upstream of Mudgee. The dam has a storage capacity of 368,120 megalitres (ML) and is operated in conjunction with Burrendong Dam to supply water to the Cudgegong and Macquarie catchments.
Members then headed downstream to visit sites along the Cudgegong River including the Putta Bucca wetlands, Rocky Waterhole, Wilbertree and Yamble Bridge.
First flow to support fish in Cudgegong River
On 1 July this year, a rule change in the Water Sharing Plan for the Macquarie Cudgegong Regulated Rivers provided greater flexibility in the management of water from Windamere Dam for environmental outcomes.
Water for the environment is being actively managed in the Cudgegong River for the first time in 2023. Previously, environmental water use was subject to ‘translucency rules’, where water was released from Windamere Dam when inflow satisfied a pre-defined threshold. Now, water managers can manage the same volume of environmental water to target ecological outcomes at any time of the year. The Macquarie Cudgegong EWAG recommended a flow event which has been developed in consultation with the NSW Department of Primary Industries – Fisheries that supports Murray cod and freshwater catfish breeding.
Starting in October 2023, a pulse of water for the environment was released from Windamere Dam into the Cudgegong River over a 3-week period to boost available nutrients and provide food for native fish. A follow-up flow over summer will help to stabilise the river level and maintain inundation of low river benches (banks and beds) where Murray cod nest and other native fish access food and habitat.
It is expected up to 9,000 ML of water for the environment will be used over the course of the event.
Supporting wetland vegetation in Macquarie Marshes
Starting in August 2023, a managed environmental flow has supported more than 30,000 hectares of wetland vegetation within the Macquarie Marshes throughout spring. These flows have also contributed to an estimated 44,000 ML into the Barwon River since June 2023.
Environmental releases are now being reduced to focus on breeding opportunities for eel-tailed catfish and Murray cod in the mid Macquarie River between Dubbo and Gin Gin weir.
Looking ahead
The Macquarie Cudgegong EWAG will meet early in the new year to review watering actions and begin planning for the water year ahead.