Presentation on theme: "Case study of sub-region Barmah-Millewa Wetlands."— Presentation transcript:
Case study of sub-region Barmah-Millewa Wetlands
Geographic Characteristics Location- the sub-region straddles two states, Southern NSW and Northern Victoria. It’s scale is 66,000ha of floodplain between the townships of Tocumwal, Deniliquin and Echuca.
Barmah ‘choke’ The capacity of the River Murray at Yarrawonga is 25,000 ML/day but at the Barmah ‘Choke’ it is only about 8,500 ML/d The Barmah Choke acts like a partial dam, forcing floodwater to frequently back up onto the floodplain, thereby inundating the extensive River red gum forests of Barmah–Millewa Forest—explaining the triangular shape of the forest.
Wetlands Are regions either temporarily or permanently covered by water and can be either natural or artificial with water that is still or flowing, fresh, brackish (slightly salty) or salty.
Why are wetlands important?
It forms the largest river red gum forest in Australia and is valued for wood products, grazing, conservation and recreation. High ecological value and cultural significance to Indigenous people and the broader community It is listed on the migratory bird agreements between Australia, China and Japan- Ramsar list of designated Wetlands of International Importance. Regularly supports 20,000 or more waterbirds- supports large breeding colonies of Australian White and Straw- necked ibis. It provides habitat for the endangered Superb parrot
The Cadell Tilt Block
The forest contains a diverse range of wetland environments and, the Murray River crayfish and many other threatened plant and animal species, including native fish and reptiles. It is an important source of food for fishes, spawning ground, nursery and/or migration path on which fish stocks, either within the wetland or elsewhere, depend. It relies on regular flooding from the Murray River for it survival. YouTube - BARMAH FOREST
Problems and changes Over the last century, the construction of dams, regulation of flow and the extraction of water to supply irrigators has changed the frequency, magnitude, timing and duration for the flooding. The Barmah-Millewa Forest is downstream of Hume Dam and Yarrawonga Weir, which regulate River Murray flows. As a result, the natural pattern of river flows and flooding in the forest has altered significantly. There is now less variability and an overall reduction in the volume of water. Storage of catchment runoff in winter and spring has reduced the frequency and extent of natural floods across the floodplain. However, water released for irrigation during the summer months has increased unseasonal flooding of low-lying floodplains. Most of the river is flooded less often and for a reduced amount of time in the past. Some low lying areas are flooded more often because of the way the river is operated for irrigation. Overall health of the forest has declined.
Living Murray Initiative Policy established in 2002 in response to declining health of the river system Aim to achieve a healthy, working, Murray River system by ensuring more water is available for the river. Strategies- $500 million to improve irrigation systems and water buy backs from willing sellers. 6 icon sites throughout the MDB.
Location of icon sites
Living Murray Ecological Objectives The Living Murray objective for the Barmah- Millewa Forest is to enhance forest, fish and wildlife values by: successful breeding of thousands of colonial waterbirds in at least three years in ten healthy vegetation in at least 55% of the area of the forest (including virtually all of the Giant rush, Moira grass, River red gum forest, and some River red gum woodland).