All of Barmah Forest’s creek regulators have been opened this week to help with native fish movement as Murray River flows start to increase.
Goulburn Broken CMA ecologist Keith Ward said this was the first time all 12 regulators were opened during winter and they should remain open until the end of September.
‘‘This trial of opening the regulators in winter will see more gradual fluctuations in flows in the forest’s creeks and will help native fish move through the system, which is critical for breeding,’’ Mr Ward said.
‘‘Traditionally, the regulators are only opened when Murray River flows downstream of Yarrawonga Weir exceed 10400Ml/day,’’ he said.
‘‘When that happens and the regulators are opened, as you can imagine, the water has built up behind the regulator gates, creating unnaturally high and fast flows that suddenly rush into the forest.
‘‘Fish ecologists believe these sudden large ‘pulses’ of water may be detrimental to native fish recruitment, survival and dispersal.’’
Flows along the Murray River below Yarrawonga are currently about 4000Ml/day and are expected to increase up to 10000Ml/day when the irrigation season starts on August 15.
Mr Ward said higher flows would also help reduce leaf litter and other organic debris building up on the forest’s floodplains.
‘‘When this gradually washes into the river it provides valuable nutrients for native fish, water bugs and other wildlife. Reducing the build-up of leaf litter on the low parts of the floodplain during winter, when air and water temperatures are lower, also reduces the likelihood of blackwater events if we get heavy rain during the warmer months,’’ Mr Ward said.