Wetlands AustraliaNational Wetlands Update September 2012
Issue No. 21, September 2012
Watering the Barmah–Millewa Forest icon site during drought and floods
Murray–Darling Basin Authority
Since The Living Murray program commenced in 2002, icon sites along the Murray River have experienced the longest drought on record, as well as record-breaking rainfall. This has provided significant challenges and opportunities for delivering environmental water to the icon sites.
The Barmah-Millewa Forest is one of The Living Murray's six icon sites. It supports the largest river red gum forest in Australia and is listed under the Ramsar Convention. When flooded, it provides an important feeding and breeding habitat for a range of species including thousands of waterbirds. The forests and wetlands rely on periods of wet and dry, with periodic large floods giving them the resilience to cope with the highly variable Australian conditions.
Site inspection of Barmah Forest in 2008.
The prolonged drought had a significant impact on the Barmah-Millewa Forest. By 2008, river red gums were under stress, turtles were dying and native floodplain fish species looked likely to die out in the local area. The forest was also unable to provide suitable habitat for waterbirds, which had been in serious decline in south-eastern Australia due to the prolonged drought.
With very little water available The Living Murray's environmental watering focused on providing refuge habitats. In 2008 water was delivered to provide a drought refuge for waterbirds as well as for the last known populations in the forest of two fish species, the southern pygmy perch and dwarf flat-headed gudgeon. The watering also aimed to connect selected freshwater pools and to prevent large-scale death of native turtles.
In 2010–11 flooding along the Murray River watered the drought-stressed floodplains and provided ecological benefits along the whole system. Some wetlands and lakes were inundated for the first time in ten years.
The rains also initiated significant waterbird breeding in the Barmah-Millewa Forest. As water levels began to fall, however, there was danger that the forest could drain before breeding was completed. Environmental water1 was used to maintain minimum water levels between high flows to allow waterbirds to complete their full breeding cycle. This resulted in the best bird breeding event in 60 years as well as providing a benefit for fish and wetland vegetation.
The 2012–13 water year
The extended high flows in Barmah-Millewa Forest have resulted in continued inundation of low-lying vegetation. This has meant that implementing a drying phase for the forest is now becoming increasingly important. This may be difficult, however, given the likelihood that the forest will experience at least some natural flooding in spring 2012, as Hume Reservoir and Dartmouth Dam are still close to full.
The Barmah-Millewa Forest icon site has not fully recovered from the impact of the longest drought in recorded history but careful delivery of environmental water both during the drought and following high flows has helped contribute to the recovery of the forest.
Environmental watering in 2010-11 at
Barmah-Millewa Forest resulted in the best bird
breeding event in 60 years. (Keith Ward)
1This water was made up of entitlements held by NSW and Victoria, The Living Murray water and water from the Barmah-Millewa Environmental Water Account.