Page 107 - VEWH Seasonal Watering Plan 2020-21
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Recent conditions
The Maribyrnong catchment has experienced below- average rainfall since the summer of 2016–17, and inflows to Rosslynne Reservoir in 2019–20 continued to track well- below average. The VEWH did not purchase allocation from licence holders in 2019–20, due to low water availability in the Maribyrnong system.
The dry conditions meant that winter/spring low-flow, winter/spring and summer/autumn freshes were not achieved in 2019–20. Summer/autumn low flows were achieved in reach 6, but only partially achieved in reach 7 (below Riddles Creek) by passing flows delivered under Southern Rural Water’s bulk entitlement. These flows prevented poor water quality conditions and maintained suitable habitat and food resources for small-bodied native fish, waterbugs and platypus.
Scope of environmental watering
Table 3.4.1 describes the potential environmental watering actions in 2020–21, their functional watering objectives (that is, the intended physical or biological effect of the watering action) and the longer-term environmental objective(s) they support. Each environmental objective relies on one or more potential environmental watering actions and their associated physical or biological functions.
Table 3.4.1 Potential environmental watering actions and objectives for the Maribyrnong system
3.4 Maribyrnong system
  Potential environmental watering action
  Functional watering objectives
    Environmental objectives
   Summer/autumn low flow (four to six ML/day during December to May)
• Maintain waterbug habitat by providing suitable depth over riffles, maintaining pools and inundating large woody debris
• Provide passage for small-bodied native fish and platypus between habitats
               Summer/autumn fresh (one to five freshes of 20–40 ML/ day for up to seven days during December to May)
• Flush pools to maintain water quality
• Scour substrates to remove fine sediment
• Wet the in-stream vegetation and streamside benches to support the growth of native streamside plants and to limit encroachment by terrestrial plant species
• Provide passage for small-bodied native fish and platypus between habitats
                      Winter/spring low flow (20–40 ML/day during June to November)
• Wet the in-stream vegetation and streamside benches to support the growth of native plants and to limit encroachment by terrestrial plant species
• Scour substrates to remove fine sediment
• Provide passage for small-bodied native fish and platypus between habitats
              Victorian Environmental Water Holder | Seasonal Watering Plan 2020–21 | 105
 











































































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