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 5.5 Broken system
Recent conditions
The Broken River catchment continued to experience dry conditions in 2019–20 on the back of two previous dry years, receiving below-average rainfall and experiencing above-average temperatures, particularly in spring/summer. Water availability in the Broken system for Moodie Swamp was very low, with high-reliability allocations only reaching two percent. Supply was better in the Murray system, enabling planned deliveries to Black Swamp and Kinnairds Wetland – which are supplied from the Murray system via the Murray valley irrigation area — to occur.
All Broken wetlands remained dry through winter, spring and summer. Environmental water was delivered to fill both Black Swamp and Kinnairds Wetland in autumn 2020,
to provide feeding and breeding habitat for a variety of waterbirds and frogs and to stimulate the growth of wetland vegetation including the listed river swamp wallaby grass
at Black Swamp and rigid and slender water milfoil at Kinnairds Wetland.
A planned delivery to Moodie Swamp in autumn 2020 was postponed due to the lack of supply and the preference
to maintain flow and water quality in upper Broken
Creek. Moodie Swamp did however receive some natural catchment runoff as a result of above-average rainfall in April/early May 2020 that provided minimal wetting of the fringing vegetation.
The postponement of the Moodie Swamp watering event in 2019–20 will extend the drying phase for this wetland to 31 months as of autumn 2021: the recommended drying phase is 6–9 months. Therefore, watering Moodie Swamp becomes more critical in 2020–21, to maintain threatened aquatic vegetation.
Scope of environmental watering
Table 5.5.5 describes the potential environmental watering action in 2020–21, its functional watering objectives (that is, the intended physical or biological effect of the watering action) and the longer-term environmental objectives they support. Each environmental objective relies on one or more potential environmental watering actions and their associated physical or biological functions.
Table 5.5.5 Potential environmental watering action and objectives for the Broken wetlands
 Potential environmental watering action
  Functional watering objectives
    Environmental objectives
   Moodie Swamp (top up in spring as required, fill in autumn)
• Promote cane grass growth
• Promote germination and growth of rigid water milfoil
• Provide habitat for brolga nesting
           270 | Victorian Environmental Water Holder | Seasonal Watering Plan 2020–21

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