Fresh for Spring in the Lachlan River

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Fresh for Spring in the Lachlan River
 
Media release: 5 August 2015 NSW Office of Environmemt & Heritage


Native fish in the Lachlan River will benefit from environmental watering this month.

A total of 20,000 megalitres of environmental water is being delivered into a 500 kilometre stretch of the river between Booligal and the Great Cumbung Swamp.

The NSW Office of Environment and Heritage has contributed 5,000 megalitres of environmental water while the Commonwealth Environmental Water Holder has provided a further 15,000 megalitres, to be delivered over a 45 day period.

Water NSW is managing the release of the water on behalf of OEH and the Commonwealth.

Commonwealth Environmental Water Holder David Papps said this event would improve connections between different parts of the river, swamp and floodplain, building on the benefits of inundation that occurred in 2013.

“We’re particularly keen to see the ongoing recovery and resilience of the Great Cumbung Swamp, which is why we’re using this environmental water to support the survival and growth of wetland vegetation such as reed beds, lignum shrublands and river red gums,” Mr Papps said.

“This flow will also support habitat for waterbirds such as straw-necked ibis, glossy ibis, egrets and other water dependent species.

“This watering event is also expected to provide drought refuge for waterbirds and other water dependent species should dry conditions continue,” Mr Papps said.

Senior Environmental Water Management Officer Paul Packard said tributary inflows higher up in the catchment had made the event possible.

“Water from tributary inflows is generally richer in nutrients than water released from the dams,” Mr Packard said.

“So, while we had planned for this event using dam water, the use of nutrient-rich water from inflows will provide even more benefits to the system.

“These nutrients feed the food web from a microscopic level up.

“When spring arrives, the ecosystem will be healthier and ready to support native fish, frogs and turtles as they become active,” Mr Packard said.

It is not expected that the flow itself will trigger fish breeding in either native fish or carp.

“If we watered when the weather was warmer, carp would breed quickly and get a head start on the available food resources,” Mr Packard said.

“By watering in winter when the water is cold, carp are not encouraged to move or breed, so when spring arrives it’s a more even playing field for the native fish.”

The flow will mimic a natural event with an early in-stream peak followed by a steady release over 35 days and a slow recession phase to minimise the risk of bank slumping.

“By watering at this time of year, we’re not competing with other river users for channel capacity, so this flow of 500 megalitres per day (at the flow’s peak) will stay within the river bank,” he said.

When the water reaches the bottom of the system it will spread through the Great Cumbung Swamp, topping up around 600 hectares of open water bodies and replenishing water levels in the reed beds totalling about 3500 hectares.

This environmental watering event is a collaborative effort between the Commonwealth Environmental Water Holder, the NSW Office of Environment and Heritage, WaterNSW, DPI Fisheries, local LLS, landholders and community members.
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