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 3.2 Yarra system
Table 3.2.1 Potential environmental watering actions and objectives for the Yarra River, Plenty River and Yarra billabongs
 Potential environmental watering action
 Functional watering objectives
 Environmental objectives
 Yarra River
       Summer/autumn low flow (80–200 ML/day during December to May)
• Physically mix pools to minimise the risk of stratification and low oxygen
• Maintain access to habitats for fish, waterbugs and platypus
                 Winter/spring low flow (200–350 ML/day during June to November)
• Physically mix pools to minimise the risk of stratification and low oxygen
• Maintain access to habitats for fish, waterbugs and platypus
• Wet bank vegetation to promote growth
                      Summer/autumn fresh (one to three freshes of 350–750 ML/day for two to four days during December to May)
    • Flush pools to prevent a decline in water quality
• Scour sediment and biofilm from gravel in riffles and pools to maintain habitat quality for fish and waterbugs
• Provide opportunities for localised movement of fish and platypus
• Wet the banks of the river to maintain flood-tolerant vegetation on the banks
                      Autumn high flow (one fresh of 560–1,300 ML/day for seven to 14 days during April to May)
 • Cue the migration of Australian grayling
• Scour sediment and biofilm from gravel in riffles and pools to maintain habitat quality for fish and waterbugs
       Winter/spring fresh (one to two freshes of 700–2,500 ML/day for three to seven days during June to November)
• Scour sediment and biofilm from gravel in riffles to improve spawning opportunities for Macquarie perch
• Wet native streamside vegetation on the banks of the river to promote growth
• Provide cues for upstream migration of juvenile migratory fish (e.g. Australian grayling and tupong)
              Spring high flow (one high flow of 700–2,500 ML/day for 14 days in September)
• Scour sediment and biofilm from gravel in riffles
• Provide prolonged wetting to favour flood-tolerant native vegetation in the streamside zone
• Provide cues for upstream migration of juvenile migratory fish (e.g. Australian grayling and tupong)
• Promote spawning of Macquarie perch
             92 | Victorian Environmental Water Holder | Seasonal Watering Plan 2020–21




































































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