Page 97 - VEWH Seasonal Watering Plan 2020-21
P. 97

Table 3.2.2 Potential environmental watering for the Yarra River, Plenty River and Yarra billabongs under a range of planning scenarios
3.2 Yarra system
  Planning scenario
   Dry
   Average
  Wet
   Expected river conditions
 • Low streamflows year round
• Lack of unregulated freshes and high flows
• Passing flows are not likely to meet the minimum environmental flow recommendations
• Potential poor water quality, particularly in summer
• Pools may stratify
• Plenty River may experience cease-to-flow events
 • Minimum passing-flow recommendations are likely to be met
• Natural flow may provide some freshes, but its duration and/or magnitude will likely be less than recommended environmental flows
• Potentially poor water quality, particularly in summer
• Pools may stratify
• Small reservoirs may spill
• Overbank flows are not likely
 • Passing flow recommendations are likely to be met
• High, natural flow will occur, most likely in winter/spring
• Major spills from reservoirs may occur
• Some natural wetting of billabongs may occur
 Expected availability of water for the environment
   • 43,000 ML
     Potential environmental watering – tier 1a (high priorities)
 • Summer/autumn low flows
• One to three summer/autumn freshes
• One autumn high flow
• One spring high flow
• Fill or partial fill of Yering Backswamp and Annulus Billabong
• Winter/spring low flows
• Winter/spring low flows (Plenty River)
• Four winter/spring freshes (Plenty River)
 • Summer/autumn low flows
• One to three summer/autumn freshes
• One autumn high flow
• One spring high flow
• Fill or partial fill of Yering Backswamp and Annulus Billabong
• Winter/spring low flows
• One to two winter/spring freshes
• Winter/spring low flows (Plenty River)
• Four winter/spring freshes (Plenty River)
 • One to three summer/autumn freshes
• One autumn high flow
• One spring high flow
• Fill or partial fill of Yering Backswamp and Annulus Billabong
• Winter/spring low flows
• One to two winter/spring freshes
• Winter/spring low flows (Plenty River)
• Four winter/spring freshes (Plenty River)
 Potential environmental watering – tier 1b (high priorities with shortfall)
  • One to two winter/spring freshes
  • N/A
  • N/A
 Potential environmental watering – tier 2 (additional priorities)
  • N/A
  • N/A
  • N/A
 Possible volume of environmental water required to achieve objectives
  • 40,000 ML (tier 1a)
• 7,500 ML (tier 1b)
   • 38,000 ML (tier 1a)
   • 29,000 ML (tier 1a)
  Priority carryover requirements
  • 3,000 ML
   Victorian Environmental Water Holder | Seasonal Watering Plan 2020–21 | 95
 































   95   96   97   98   99