Monday, April 15, 2024

Recent fish deaths reignite management frustration – Part 2

Recent stories

Continued from last week

For six generations, the Lunghusen family have farmed on Gunbower Creek. The recent fish deaths have Jason Lunghusen questioning the current management of the creek and how much say the community actually has in these top-down government-run projects. 

“The creek’s our backyard, nobody knows the creek better than the people who live here,” said Jason.

Jason said the original planning of the Hipwell Regulator on Gunbower Creek was a prime example of how little weight community wisdom holds when it comes to government projects. 

“I gave up trying to get through to North Central Catchment because they completely ignored us all.”

Jason and his fellow farmers had their low country and pumps flooded out when the channel capacity of the creek was exceeded.

“They mentioned how much water they were going to put down the creek for the flooding of the forest, and we said no, that was impossible.

“You can’t fit the volume of water down the creek, it’s too narrow. 

“It’s a restriction to the whole system.”

Despite landholder concerns, the design flow rate for Hipwell Regulator remained at 1,600 megalitres per day, when in reality, only around half of that flow rate was possible.

“They went ahead to try and put that amount of water through it when they built it and they flooded everything.

“They flooded box country, they flooded the bottom of our farms, water was backing up our drains, all the extra water went everywhere.

“All our pumps were flooded.”

After the flooding event, an emergency meeting was held with landholders, the Murray-Darling Basin Authority, Goulburn-Murray Water and North Central Catchment Management Authority and it was conceded the flow target for Hipwell’s was derived by considering the offtake capacity for Gunbower Creek, not the channel capacity further down the creek. 

It is not known how much money could have been saved building the Hipwell’s regulator at the true flow capacity, and even at lower flow rates. Jason said the demands placed on the creek now are taking a toll.

“They’re putting too much water down the creek for too long,” said Jason. 

“The banks are becoming too eroded; trees are falling in and further restricting flows.”

It’s not the first time erosion has been under the spotlight on Gunbower Creek. The [Koondrook and Barham] Bridge caught up with Mal Johnson at the Gunbower Creek in 2020, www.thebridgenews.com.au/remote-management-local-risk, as Mal reported over 20 metres of the river bank had disappeared under the new management regime adding to silting up of the creek and aiding in aquatic weed proliferation. 

Jason’s views are shared by others, who have had a lifetime of experience on the creek and now hold concerns for the creek’s future.  

Dr Peter Barker OAM took to commenting on the North Central CMA Facebook page about the current Gunbower Creek water quality. 

‘The last two years the water is so full of debri I’m not game to swim in it. I’m not sure if your environmental flows on to Gunbower Island coupled with the rain has caused it, or if it’s due to the huge freshwater mussel kill that happened with the Blackwater event last year. Water quality has never been lower in the creek.’

Additional challenges facing the creek have been the huge number of carp breeding in the forest, a problem shared with much of the Murray-Darling Basin. 

North Central CMA said being able to close the fishway to protect Gunbower Creek from Basin-wide and region-wide carp breeding events in the warmer months is a positive for the creek and the community.

“The Koondrook Fishway was first closed in January 2023 after carp numbers increased across the Murray-Darling Basin in response to the 2022 floods, to prevent significant numbers travelling up into the Gunbower Creek. 

“The fishway was re-opened in April 2023, after the carp accumulation at Koondrook Weir dissipated. 

“Monitoring of the fishway was undertaken during the high Murray River unregulated flows in spring 2023 and trapping provided critical real-time data on when to close it again. 

“Monitoring and trapping of the fishway during spring 2023 highlighted large numbers of native fish such as golden perch, bony bream and even a freshwater catfish were moving through the fishway.

“The fishway was closed again in early November as carp began to outnumber native fish.”

Research completed by the Arthur Rylah Institute for Environmental Research ‘Managing Flows and Carp – Technical Report Series No. 255’ provides evidence of why increased environmental flows that re-inundate wetlands (including the Lower Lakes) will result in significant breeding of carp, and allow for movement of now trapped populations back into the main river system. Todd et al 2024, ‘Modelling the response of common carp (Cyprinus carpio) to natural and managed flows using a stochastic population model’, also support that environmental water can significantly increase the abundance of carp – “Artificial inundations generated by floodplain infrastructure, however, caused significant carp recruitment compared to baseline scenarios.”

In 2016, the Commonwealth announced a $15M investment to develop the National Carp Control Program as a long-term biological control plan for the invasive species. However, the project stalled due to the lack of information about the biomass-impacts relationship.

It remains to be seen what the current state and federal governments will do to manage carp impacts as they have a direct impact on our native species, like predation and competition for food sources.

The Koondrook and Barham Bridge Newspaper 29 February 2024

This article appeared in The Koondrook and Barham Bridge Newspaper, 29 February 2024.

Related story: Recent fish deaths reignite management frustration

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