Northern fish flow sees Walgett weir run over for first time in a year

Fish flow release brings heart to communities along the Barwon

After 330 days, the Walgett weir is finally running over.

After 330 days, the Walgett weir is finally running over.


Big river flush reaches Walgett


For a town that just lost its only supermarket in a fire, seeing its river flush with water for the first time in 330 days was a source of great relief.

Towns along the northern river systems are celebrating the Northern Fish Flow release - and now even people are catching fish.

The water has finally passed over the Walgett weir, running at 480 megalitres a day. The event comes just a week after the town lost its only supermarket in a fire. The NSW Government has provided emergency funding for a temporary supermarket.

Related: Walgett IGA fire: supermarket destroyed, exclusion zone in place

Meanwhile, according to Jason Wilson, local engagement officer from the Commonwealth Environmental Water Office, the advent of the water reaching Walgett from way up the top of part of the system's source at Copeton Dam, has lifted spirits immeasurably. The Walgett weir has been stagnant for 330 days.

The good news also is that the river flush has not brought down any dirty or black water and it is extremely clean.

Also farmers along stretches of the Barwon have now been able to source water for stock and domestic use.

What Walgett weir looked like before the flush.

What Walgett weir looked like before the flush.

The river flush will enhance the breeding prospects of many native fish including the Murray cod and yellowbelly, most of which were trapped in pools along the Barwon until the flush.

The CEWO has been conducting well-attended community meetings about the fish flow.

Water flows down the Mehi-Barwon system from Northern Fish Flow release.

The CEWO said it was "very unusual for the Barwon River not to be flowing. The Barwon River between Collarenebri and Walgett flowed on over 97 per cent of days in autumn and winter between 1980 and 2018, which included the Millennium Drought".

"As a result of the Northern Fish Flow the water in the waterholes in the Macintyre, Mehi and the Barwon rivers is expected to provide good conditions for fish and native animals for several months prior to the heat of summer. This is because of lower evaporation rates over winter than summer and good dissolved oxygen. If there is a flow in the river following rainfall, it will push further down the river system as the waterholes will be starting near full.

"The Northern Fish Flow has been carefully timed, waiting until cooler autumn months. Monitoring of dissolved oxygen in the Collarenebri weir pool in summer (February) suggested the fish present might be at risk from low oxygen. This risk came from potential mixing of deoxygenated water at the bottom of waterholes with the water in the top when air temperatures are hot. This could have done more harm than good for native fish."

About 36 GL of NSW and Commonwealth water will be used in the Northern Fish Flow, contributed equally by NSW and the Commonwealth.

The water will run as far as about where the Barwon meets the Macquarie river, and will not quite make Bourke.

Some tributaries of the Barwon river system will also run for the first time in almost a year.


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