Page 224 - VEWH Seasonal Watering Plan 2020-21
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 5.2 Victorian Murray system
Traditional Owner cultural values and uses
The Hattah Lakes system is part of a highly sensitive region for Aboriginal cultural heritage values and contains considerable evidence of past Aboriginal occupation. More than 1,000 Indigenous archaeological sites at the Hattah Lakes are registered with Aboriginal Victoria.
The local Aboriginal community maintains strong connections to the land and its resources such as native species used for food and medicine.
Mallee CMA and members of Tati Tati, Latje Latje, Gilby Corporation and Munutunga discussed a range of options for how environmental flows can be delivered at Hattah Lakes in 2020–2021. Elders spoke of the importance
of drying cycles for wetlands and the abundance of the culturally significant old man weed that is flourishing on the drying lake beds. They also warned of not leaving the system dry too long and provided advice on the method of mimicking natural inundation when water does return. Their recommendations for watering actions have shaped environmental water planning for 2020–21.
Social, economic and recreational values and uses
In planning the potential watering actions in Table 5.2.10, Mallee CMA considered how environmental flows could support values and uses including:
• water-based recreation (such as canoeing, kayaking and fishing)
• riverside recreation and amenity (such as camping, photography, birdwatching and bushwalking)
• community events and tourism (such as ‘Junior Ranger’ school holiday programs including bushwalking, birdwatching and bug hunting, school education programs, citizen science projects (microbats), tours involving kayaking, mountain bike riding, camping, fishing and swimming)
• socio-economic benefits (such as beekeeping).
Recent conditions
Weather observations at the nearest weather station to Hattah Lakes in Ouyen indicate there was below-average rainfall and above-average temperatures in the area during 2019–20. The average maximum temperature at Ouyen during 2019–20 was less than the previous year, but long- term data indicates that temperatures have increased over the previous 10 years. Rainfall totals were substantially below average for the year. Overbank flows from the Murray River affect the ecology of the Hattah Lakes floodplain more than local weather conditions, but the trend of increasing temperature and decreasing rainfall is harmful to plant and animal communities between floods.
2019–20 was dry across the entire Murray River valley and the major upstream tributaries that contribute flows to the mid-Murray river system. There were no spills from major upstream storages and the magnitude of operational flows and environmental flows that were released was well below the threshold for inflows to Hattah Lakes.
Decisions about environmental watering interventions at Hattah Lakes during 2019–20 focussed on the need to water Lake Kramen — a disconnected wetland at the fringes of the system — and the need to dry the main southern Hattah Lakes.
At Lake Kramen, observations of tree health indicated
that environmental watering was necessary during spring 2019 to avoid a permanent decline of vegetation condition, therefore environmental water was released as planned to Lake Kramen during August to October 2019.
Water for the environment delivered the last flood in the southern Hattah Lakes wetland complex in 2017. The wetlands have been allowed to draw down since then, and the last wetlands to hold water dried in February 2020. The moisture remaining in the lake-bed soils and local rainfall is supporting the growth and recruitment of specialised lake- bed native vegetation.
If there is no natural wetting before autumn 2021, the lake-bed vegetation in the southern Hattah Lakes will have likely completed its life cycle and will die off, due to reduced soil moisture. Water for the environment may be used in autumn/winter 2021 to refill these wetlands and restart
the important wetting and drying cycle. Lake Kramen is expected to gradually draw down over several years. The planned timing of future environmental watering at Lake Kramen will be determined by the condition of the fringing vegetation.
Scope of environmental watering
Table 5.2.10 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.
    222 | Victorian Environmental Water Holder | Seasonal Watering Plan 2020–21

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