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 5.5 Broken system
Traditional Owner cultural values and uses
Goulburn Broken CMA consulted with Yorta Yorta Nation Aboriginal Corporation during the planning of environmental water deliveries in the lower Broken Creek. The environmental and ecological objectives of the proposals were supported and align with the broad values of caring for Country. Goulburn Broken CMA and Yorta Yorta Nation Aboriginal Corporation will explore further opportunities to deliver environmental water to support Yorta Yorta cultural values throughout the year.
Yorta Yorta Nation Aboriginal Corporation raised concerns about the cultural damage water transfers are having on the lower Goulburn River and the Barmah Choke in addition
to the ecological damage being caused. Using the lower Broken and Nine Mile Creeks for delivery of water (either environmental or consumptive) to the lower Murray River as a bypass mechanism may help reduce the risk of erosion on the Barmah Choke and lower Goulburn River and thus help to protect culturally significant values.
Social, recreational and economic values and uses
In planning the potential watering actions in Table 5.5.3, Goulburn Broken CMA considered how environmental flows could support values and uses including:
• water-based recreation (such as canoeing, fishing and kayaking)
• riverside recreation and amenity (such as game hunting)
• socio-economic benefits (such as diverters for irrigation, domestic and stock uses, and water quality including preventing algal and azolla blooms).
Recent conditions
The Goulburn Broken region had below-average rainfall and above-average temperatures for most of 2019–20. Rainfall at Numurkah during the first half of 2019–20 was just over half of the long-term average for this period, resulting in low inflows to the local catchment. Water for the environment from the Goulburn and Murray system portfolios was used in combination with operational water to meet flow targets throughout the year.
Flow in lower Broken Creek was lower than planned during winter 2019–20, due to maintenance works on the Yarrawonga Main Channel and the East Goulburn Main Channel. Consequently, fish ladders were closed in July 2019 to hold water in the system to maintain fish habitat. Some water was delivered to the creek from secondary outfall irrigation channels, but flow in reaches 3 and 4 dropped to 15 ML per day on occasions, which is well below the recommended minimum winter target of 40 ML per day.
The flow increased to 250 ML per day at the start of the irrigation season in August 2019, and the rapid increase likely cued some fish movement through the system. IVTs from the Goulburn system and Murray choke bypass flows increased flow in lower Broken Creek to 500 ML per day in late October 2019, which likely cued further fish movement and spawning and flushed azolla. The average flow at Rice’s Weir remained around 410 ML per day through summer and early autumn as operational water transfers to the Murray continued. Water for the environment was delivered in conjunction with operational deliveries from late March 2020 to maintain a flow of about 200 ML per day until the end of the irrigation season.
There is limited ecological monitoring in lower Broken Creek, but members of the Broken Environmental Water Advisory Group have reported a marked improvement in water quality since targeted environmental water deliveries started in 2010–11. The delivery of minimum low flow during the off-irrigation season provided winter foraging habitat and instream refuge areas, especially important for young-of- year fish, platypus, rakali (water rats) and turtles.
Scope of environmental watering
Table 5.5.3 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 objectives they support. Each environmental objective relies on one or more potential environmental watering actions and their associated physical or biological functions.
   266 | Victorian Environmental Water Holder | Seasonal Watering Plan 2020–21

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