Native fish were the focus of managed watering events in the Lachlan catchment in 2017–18.
In collaboration with WaterNSW and the Commonwealth Environmental Water Office, OEH managed the delivery of 42,937 megalitres of water for the environment at key times throughout the year. This enabled fish to move and breed along the length of the Lachlan River.
To provide suitable flow conditions during the spring Murray cod spawning season, water for the environment was released to stabilise river levels between peaks of irrigation demand. Monitoring confirmed large numbers of small-bodied native fish such as Australian smelt and flat-headed gudgeon spawning. Repeat visits showed that larval size was generally increasing, indicating survival and growth.
As flows were delivered to the full run of the river below Wyangala Dam, seasonal pulses occurred into anabranch creeks maintaining habitat and opportunities for fish to move and access habitat and enhancing their connection with the Lachlan River. Freshwater catfish responded to a flow pulse in the Booberoi Creek.
Adaptive re-use of water already released for the environment to the Lachlan River and Lake Brewster, enabled the delivery of ‘freshes’ (or pulses of water) into the Booberoi Creek in spring and winter, and into the Lachlan River below Brewster to support fish populations into winter. When these flows arrived at the Great Cumbung Swamp, they partially inundated the reed beds, open water bodies and fringing wetland vegetation.
At Noonamah in the lower Lachlan, 41 megalitres of water for the environment that had already supported fish populations in the river below Brewster, was adaptively re-used. This water supported the continued recovery of a small black box wetland near Lake Bullogal where southern bell frogs were recently recorded for the first time in the Lachlan since the 1970s.
Waterbirds converged on the Noonamah black box swamp and the Great Cumbung Swamp after the arrival of water to take advantage of food resources associated with newly wetted ground and wading habitat.