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Recent conditions
Weather observations at Lake Victoria — the nearest weather station to Lindsay, Mulcra and Wallpolla islands — indicate there was below-average rainfall and above- average temperatures in the region during 2019–20. The average maximum temperature at Lake Victoria during 2019–20 was less than in the previous year, but long-term data indicates that temperatures have increased over the previous 10 years. Monthly rainfall totals were substantially below average for the year.
The 2019–20 year was mostly dry in the entire Murray River valley and major upstream tributaries (such as the Goulburn and Murrumbidgee rivers). There were no spills from major upstream storages, and the magnitudes of operational flows and environmental flows that were released in the Murray system were well below the threshold required to provide flows to wetlands and floodplains at Lindsay, Mulcra and Wallpolla islands. Summer floods in northern New South Wales (NSW) and Queensland provided flow in the Darling River and in April 2020 the Darling River provided substantial flow to the Murray River for the first time in more than two years. This inflow was well below the magnitude needed to wet Lindsay, Mulcra and Wallpolla islands.
All of the high-priority potential watering actions were delivered during 2019–20. These included year-round
flows to maintain fish habitat in Mullaroo Creek and spring high flows in Mullaroo Creek, Potterwalkagee Creek and the upper reaches of the Lindsay River to help native fish disperse, spawn and recruit. Water for the environment was also pumped to wetlands and creeks on Wallpolla Island
in spring and autumn, to improve vegetation condition and provide habitat for waterbirds and fish.
Scope of environmental watering
Table 5.2.14 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.
5.2 Victorian Murray system
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