A total of 24.9 GL of environmental water, including 22.5 GL of Commonwealth environmental water, was delivered to the North Redbank wetlands on the lower Murrumbidgee floodplain between November 2011 and February 2012 to support wetland species and habitat. Commonwealth environmental water was delivered in two stages:
25 November 2011 – 2 February 2012
A total of 20.2 GL of environmental water, including 17.8 GL of Commonwealth environmental water, was delivered to the North Redbank wetlands to maintain water levels and water quality at the wetlands with the following specific ecological objectives:
- To provide breeding habitat for numerous waterbird species including great egret, glossy ibis, blue billed duck, Australasian bittern and the fishing bat (Myotis macropus), which is vulnerable in NSW.
- To create breeding habitat for southern bell frogs (Litoria raniformis), which is nationally vulnerable and endangered in NSW.
- Inundate river red gum (Eucalyptus camaldulensis) forest and associated wetland systems including lignum (Muehlenbeckia florulenta), black box (E.largiflorens) and native reed (Phragmites australis) communities.
This watering action was managed in cooperation with the NSW Office of Environment and Heritage, State Water and local landholders.
3 – 14 February 2012
A further 4.7 GL of Commonwealth environmental water was delivered to the North Redbank wetlands over a period of 11 days in February 2012 to prolong the period of wetland inundation from the earlier action. The additional period of wetland inundation provided breeding habitat for waterbirds and the southern bell frog, supported vegetation recovery and improving water quality. While environmental water was being delivered to the wetlands from the North Redbank channel, water was simultaneously released from the wetlands (at Baupie Escape near Balranald) into the Murrumbidgee River to increase system connectivity to allow the transfer of carbon, sediment, nutrient and biota between wetlands and the Murrumbidgee River.
A concurrent in-stream fresh was delivered to the lower Murrumbidgee River channel during 11-29 February 2012 to mitigated against possible negative ecological impacts of low dissolved oxygen return flows from the North Redbank wetlands on the Murrumbidgee River channel (see Environmental watering in the lower Murrumbidgee River).