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 5.7 Loddon system
Scenario planning
Table 5.7.4 outlines the potential environmental watering and expected water use under a range of planning scenarios.
Topping up Lake Meran to maintain the water level between 77.3 and 77.8 m AHD is a high priority under all scenarios, to manage the lake’s salinity for aquatic animals and provide permanent refuge for fish and Murray River turtles. If under a wet scenario natural flows raise the water level
in Lake Meran significantly above 77.8m AHD, water for the environment may be used to achieve a complete or near-complete fill for the remainder of 2020–21. Waterway managers will respond adaptively depending on the level of natural inflow, climatic forecasts and environmental conditions.
Lake Yando has been dry for over two years and filling it in 2020–21 is a priority under all scenarios, to support vegetation germination and growth.
A fill of Lake Leaghur is planned to be provided between late winter and spring under average and wet scenarios, to maintain the health of mature streamside vegetation and to promote seedling recruitment. Deliveries will be subject to planned channel infrastructure upgrades being completed before optimal filling times. While desirable under an optimal watering regime, this delivery is less of a priority compared to other sites under drought and dry scenarios, as one more year of drying is tolerable under its environmental management plan. However, if Lake Leaghur remains dry
in 2020–21, filling the wetland in 2021–22 will become a high priority to meet minimum watering recommendations. Where applicable, additional top-ups may be provided to Lake Yando and Lake Leaghur to ensure adequate food resources for nesting waterbirds if significant waterbird breeding occurs.
Lake Boort is currently dry and is planned to be allowed to remain dry to prevent over-watering trees and to allow them to grow. Unless filled naturally, Little Lake Meran is planned to continue to be drawn down to a minimum level or to
dry completely. This will provide an important dry period, to promote the growth of herbland plants and fringing vegetation.
Most wetlands are expected to fill naturally from large overland floods under a wet scenario.
Table 5.7.4 Potential environmental watering for the Boort wetlands under a range of planning scenarios
 Planning scenario
    Drought
  Dry
    Average
   Wet
 Expected river conditions
   • No natural inflows to wetlands
 • Minimal natural inflows to wetlands from local catchment runoff possible
   • Periods of high
flow combined with localised catchment contributions, which are expected to provide minor inflows to wetlands
  • Extended durations of high flow and overbank flow from creeks and flood runners, which fill most wetlands
  Potential environmental watering – tier 11 (high priorities)2
  • Lake Meran (top- ups)
• Lake Yando (fill)
• Lake Yando (top up, if triggered)
• Lake Meran (top- ups)
• Lake Yando (fill)
• Lake Yando (top up, if triggered)
  • Lake Meran (top- ups)
• Lake Yando (fill)
• Lake Leaghur (fill)
• Lake Yando and Lake Leaghur (top up, if triggered)
 • Lake Meran (top- ups)
• Lake Meran (fill, if required)
• Lake Yando (fill)
• Lake Leaghur (fill)
• Lake Yando and Lake Leaghur (top up, if triggered)
 Potential environmental watering – tier 2 (additional priorities)2
  • Lake Leaghur (fill)
• Lake Leaghur
(top up, if triggered)
   • Lake Leaghur (fill)
• Lake Leaghur
(top up, if triggered)
   • N/A
 Possible volume of environmental water required to achieve objectives3
   • 3,400 ML (tier 1)
• 2,000 ML (tier 2)
 • 3,400 ML (tier 1)
• 2,000 ML (tier 2)
  • 5,400 ML (tier 1)
   • 5,400–11,400 ML (tier 1)
  1 Tier 1 potential environmental watering for the Boort wetlands is not classified as tier 1a or 1b because the water available for use is shared across various systems and it is not possible to reliably determine the supply specifically available for the Boort wetlands
2 Wetlands are listed in priority order for tier 1 and tier 2 under all scenarios.
3 Environmental water requirements for tier 2 actions are additional to tier 1 requirements.
296 | Victorian Environmental Water Holder | Seasonal Watering Plan 2020–21









































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