Page 116 - VEWH Seasonal Watering Plan 2020-21
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 3.5 Werribee system
Table 3.5.2 Potential environmental watering for the Werribee system under a range of planning scenarios
  Planning scenario
   Dry
   Average
  Wet
   Expected river conditions
 • No natural flow below Melton Reservoir
• Minimal passing flows to reach 6, possible transfers during summer
• Some consumptive releases out of storage into reach 8 in summer/autumn
 • Unregulated spills in winter/ spring from Melton Reservoir into reaches 8 and 9 and the estuary; most low flows in reach 6 met by passing flows
• Consumptive releases out of storage into reach 8 in summer/autumn
 • Unregulated spills in winter/ spring from Melton Reservoir into reaches 8 and 9 and the estuary; all low flows in reach 6 provided
• Consumptive releases out of storage into reach 8 in summer/autumn
 Expected availability of water for the environment1
   • 2,154 ML
   • 2,789 ML
   • 3,039 ML
   Potential environmental watering – tier 1a (high priorities)
 • Three spring freshes (reach 6)
• One spring/summer high flow (reach 6)
• Winter/spring/summer low flows (reach 6)
• Three summer/autumn freshes lower Werribee River
• One winter/spring fresh lower Werribee River
 • Four spring freshes (reach 6)
• Three spring/summer high flows (reach 6)
• Winter/spring/summer low flows (reach 6)
• Five summer/autumn freshes lower Werribee River
• One winter/spring fresh lower Werribee River
 • Four spring freshes (reach 6)
• Three spring/summer high flows (reach 6)
• Winter/spring/summer low flows (reach 6)
• Five summer/autumn freshes lower Werribee River
• Two winter/spring freshes lower Werribee River
• Summer/autumn low flows lower Werribee River
 Potential environmental watering – tier 1b (high priorities with shortfall)
  • Summer/autumn low flows lower Werribee River
• Additional winter/spring fresh lower Werribee River
  • Summer/autumn low flows lower Werribee River
• Additional winter/spring fresh lower Werribee River
  • Increased duration summer/ autumn low flows lower Werribee River
 Potential environmental watering – tier 2 (additional priorities)
  • Increased winter/spring low flows lower Werribee River
  • Increased winter/spring low flows lower Werribee River
  • Increased winter/spring low flows lower Werribee River
 Possible volume of environmental water required to achieve objectives2
  • 930 ML (tier 1a)
• 1,580 ML (tier 1b)
• 10,000 ML (tier 2)
   • 1,250 ML (tier 1a)
• 1,580 ML (tier 1b)
• 10,000 ML (tier 2)
   • 1,880 ML (tier 1a)
• 900 ML (tier 1b)
• 10,000 ML (tier 2)
  Priority carryover requirements
  • 980 to 1,060 ML3
  1 Includes water shares held by Melbourne Water that may be transferred to the VEWH for use in the Werribee system.
2 Environmental water requirements for tier 2 actions are additional to tier 1 requirements.
3 A minimum volume of 200 ML is required to be carried over in Lake Merrimu to meet demands in Pyrites Creek.
   114 | Victorian Environmental Water Holder | Seasonal Watering Plan 2020–21






































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