Water for the environment working hard in the Wambuul Macquarie Valley.

Wise use of publicly owned water for the environment in the 2018-2019 water year helped vegetation in the core 10% of the struggling Macquarie Marshes hold on through the extreme drought of 2017-2019.

The rains in February 2020 came just in time to provide relief to the burnt North Marsh reed bed – however some fumbling in NSW agencies meant that the first flows weren’t protected for the environment, and significant volumes of water were allowed to be pumped and diverted from the river.

As a result, parts of the Ramsar listed wetlands turned green with noxious weeds, looking healthy to the untrained eye – but only flood water can heal a wetland. It wasn’t until late April 2020, when the growing days were shortening, that flows finally reached the northern part of the Marshes and the Lower Macquarie.

The start of the new water year as of 1st July 2020 saw some water that had been allocated to customers in 2016 finally turn up in the dam and be available, followed by some more flows. Time to get some important flows into the valley for native fish recovery and vegetation in the Macquarie Marshes.

The first part of the flow was designed to support Gugabul- Murray Cod on the nest.

And success!

Despite a hiccup with the cold water pollution control curtain in Burrendong which sent chilly 12 degree water down the river, NSW DPI – Fisheries detected Murray cod larvae in the Trangie area in mid-October. Based on larval ages, hatching of eggs began at the start of October.

The timing and duration of flows to the Macquarie Marshes is also critical for the recovery of this internationally significant wetland system. Plants in core wetland areas typically need 2–3 months of inundation over the post-frost months to allow them to flourish. This gives them a better chance to out-compete weeds such as lippia and noogoora burr.

With the landscape becoming drier, river operations getting tighter and the volumes of water available to fill water orders rapidly decreasing, environmental water managers are doing an excellent job supporting aquatic life in Wambuul.

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