Annual environmental water priorities in the Lachlan valley

Recovery and refuge are the focus of water for the environment in the Lachlan valley.

Priorities for 2017–18

 Climate models are indicating a neutral El Nino-Southern Oscillation for the second half of 2017 with warmer and drier than average conditions expected in winter across Australia.

As a result of recent floods, availability of planned and licensed water is expected to be high. Water managers and the Lachlan Environmental Water Advisory Group have prepared watering plans that take into consideration a range of weather and water availability scenarios, in case it rains more or less than expected. This is known as ‘Resource Availability Scenario’ planning. Wet scenario actions are proposed for the Lachlan valley.

Further details on watering priorities for 2017–18 can be found in the Statement of annual environmental watering priorities 2017–18 (PDF 2.5MB).

Highlights from 2016–17

Significant flooding, successful breeding of waterbirds

During the 2016–17 watering season, there was significant flooding in the Lachlan, its tributaries and across the floodplains. Translucent releases (350 gigalitres) stimulated a strong early response from river systems, and then following significant natural inflows, environmental water was managed to support and maintain the health of the rivers and creeks, to support recovery of floodplain wetlands, and to enable waterbirds to breed successfully.

Flows down the Lachlan River channel to the Lower Lachlan Swamp, Booligal Wetlands and Great Cumbung Swamp eventually connected with the Murrumbidgee River to provide a rare incidence of connection between the two.

Environmental water manager Paul Packard said environmental flows of 33 gigalitres together with 15 gigalitres of water quality allowance water were released into the Lachlan River below Wyangala Dam to provide refuge for native fish during the period when oxygen-depleted water was returning from the floodplain. Environmental water was carefully managed to avoid nuisance flooding and to provide an extended, gentle recession in river levels’.

'When environmental water reached the lower Lachlan it enhanced the spread and duration of inundation in the Cumbung Swamp, with over 10,000 hectares of wetland habitat getting a much needed inundation.

'Environmental flows of 1.3 gigalitres, together with 3.5 gigalitres of Environmental Contingency Allowance, were delivered into the Merrimajeel Creek. This flow supported successful completion of a colonial breeding event of more than 8000 pairs of straw necked ibis, glossy ibis, white ibis, spoonbills and rufous night herons in the Booligal Wetlands.’

Lake Brewster experienced a significant and extended pelican breeding event with up to 8000 nests established across the summer and autumn. Fifteen gigalitres of Environmental Contingency Allowance was committed to maintain water levels in the lake to support successful completion of pelican breeding.