A growing number of landholders on the Darling River are installing fish protection screens on their water pumps in an effort to save native fish species.
Key points:
- Since 2020 Western Local Land Services has issued fish screen grants to nine landholders on the Darling River
- The screens come in a variety of designs but all prevent fish in their early life stages being sucked out of the river
- More grants through the Murray-Darling Healthy Rivers Program will open soon, enabling fish screens to be installed across all Western NSW river systems
The screens were designed to ensure fish species such as Murray cod and golden perch, along with their eggs and larvae, were not sucked into irrigation infrastructure.
Organic almond grower Andrew Rix said he was enticed by a Local Land Services grant that covered 25 per cent of the costs of the fish screen.
His device sits on top of the water and has three rotating mesh cylinders that are sprayed with water, so that anything stuck to the outside of the screen is returned to the river.
"The fish screen I chose offered the finest filtration, which is twice as fine as any filtering I was doing doing previously, which reduces all the algae and clogging of the drip hose," Mr Rix said.
The fish screen was designed to stop rotating if jammed, and Mr Rix said roughly once a week he needed to walk down the gangway to clear an obstruction but the benefits outweighed the disadvantages.
The Darling River plays a critical role in native fish breeding and migration.(ABC Rural: Kellie Hollingworth)
Not just environmental benefits
While the river is high at the moment, there are times when it stops flowing.
But Mr Rix said his fish screen floated and was likely to keep operating when the river level dropped.
"Because we're in the upper reaches we normally have about 1.5 metres of water at pool level and predictions are in the future they may have to drop that half a metre, so in peak demand, leaving us with a metre," he said.
"The old foot valves would have vortexed and sucked air. These new ones, because they're over a bigger surface area and they float, I'm told they'll only need about 30-40 centimetres of water to operate."
Duxton Vineyards installed two mesh fish protection screens on the pumps for its 130-hectare Avoca vineyard, upstream of Pomona.
Duxton Vineyards' fish screen was installed in April 2022.(ABC Rural: Kellie Hollingworth)
"It actually works off the suction of the water, which turns an internal propeller that causes the screen to rotate in a cylindrical fashion," the company's environmental manager Dylan Klingbiel said.
"And it has a brush on the inner and outer surfaces, the brush frees and removes any material that accumulates, keeping things like fish or sticks and leaves in the river system."
Mr Klingbiel said compared to a standard irrigation screen, it had a very low sphere of influence in the river system.
Duxton Vineyard's environmental manager Dylan Klingbiel and general manager Wayne Ellis at the pump where fish screens have been installed.(ABC Rural: Kellie Hollingworth )
Duxton Vineyards general manager Wayne Ellis said the company was planning to install more fish screens at the other pumping stations it operated on the Darling River.
"We think in a full season you'd get a return on investment just from inside the business opposed to what it's doing to the environment," he said.
Due to the high water levels in the Darling this season, four of the foot valves at one of the vineyards were crushed by debris in February, taking the irrigation system offline.
Mr Ellis said the engineering of the fish screens removed the risk of being unable to irrigate while also benefiting the river.