Barmah National Park

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The Barmah National Park, formerly Barmah State Park, is a national park located in the Hume region of the Australian state of Victoria. The park is located adjacent to the Murray River near the town of Barmah, approximately 225 kilometres (140 mi) north of Melbourne. The park consists of river red gum floodplain forest, interspersed with treeless freshwater marshes. The area is subject to seasonal flooding from natural and irrigation water flows. The 60,000 hectares (150,000 acres) Barmah-Millewa Forest, consisting of the Barmah Forest (Victoria) and the Millewa group of forests (New South Wales), forms the largest river red gum forest in the world. The Barmah Forest Ramsar site is an internationally recognised wetland, listed under the Ramsar Convention, and a number of bird species that utilise the Barmah National Park are part of the Japan-Australia Migratory Bird Agreement and the China-Australia Migratory Bird Agreement. Note that the areas of the Barmah National Park and the Barmah Forest Ramsar site mostly overlap, but are not identical, Barmah National Park site includes the western part of Ulupna Island in the north east, but not the Murray River Park to the south east. The...

The Barmah National Park is known as a temperate semi-arid region, with low rainfall and high evaporation. Average temperature maximums for the year are around 30 °C (86 °F) in January and February, with average minimum temperatures down to 4 °C (39 °F) in July. Average rainfall for the year is 400 millimetres (16 in), with the most rain falling in winter with an average monthly rainfall of 40 millimetres (1.6 in).

The Barmah Forest was originally utilised by Indigenous Australians, including the Yorta Yorta and Bangerang people, to find food, shelter and materials. Following the settlement of Europeans into the area, Barmah Forest became an important fishing and logging area, with surrounding land cleared for agriculture and grazing. Rabbits, foxes, sheep, cattle and horses were introduced into the area. Hardwood timber was harvested from the Barmah region from around 1870, and logging of river red gum and seasonal cattle grazing were important local industries until recently, ceasing when the national park was created. The Barmah muster yards, located in the southern end of the park, and used for management of cattle grazed in the surrounding river red gum forests, were heritage listed in 2009. Cattle grazing was banned in all river red gum national parks in 2015. The park contains a large population of wild horses, which mainly originate from free roaming horses that either escaped or were purposely released for breeding stock in the mid 1800s. Stock released by a local trotting horse breeder after 1952 bolstered their population after the last great roundup of 1949, when approximately 70 wild horses remained in the Barmah Forest.

Barmah State Park was established in 1987, and was legislated as Barmah National Park in 2010. The park is one of four river red gum national parks established by the Victorian Government in 2010 to protect remnant river red gum forest. The other river red gum national parks are the Gunbower National Park (created 2009), Hattah-Kulkyne National Park (1978), Lower Goulburn National Park (2009), Murray-Sunset National Park (1991) and the Warby-Ovens National Park (2009).

In July 2010, the Government of New South Wales declared the Millewa Forest, on the northern banks of the Murray River, as a national park. The 41,601-hectare (102,800-acre) forest was renamed as the Murray Valley National Park, making the combined reserves a 70,000-hectare (170,000-acre) cross–border national park, managed by both governments and the traditional owners.The combined parks are the largest continuous red gum forest in the world.

- See also: Murray River § Cadell Fault and formation of the Barmah Red Gum Forests

The Barmah Choke and the Narrows, a section of the Murray River where flow is restricted by a geological fault (the Cadell Fault ), naturally cause the overflow of water into the Barmah Forest when the river flow is high.

Historically, the Barmah National Park and surrounding river red gum forests would flood naturally in winter and spring in most years, and river flows were very low in late-summer and autumn. Since clearing for agriculture and the subsequent dam construction took place, the Murray River has undergone extensive flow regulation. The construction of dams upstream from the Barmah National Park, from the 1920s onwards, has had a vast impact on the water flowing in the Murray River and instances of flooding, the flow of water is now highly regulated. The Hume Dam was operational from 1936, the Yarrawonga Weir in 1939, and the Dartmouth Dam from 1979.

As a consequence of flow regulation, the winter and spring floods are now reduced, and of shorter duration than previously, with more low level flooding occurring in summer and autumn. The increased incidents of smaller summer and autumn floods, which affect low-lying areas of Barmah National Park, are sometimes caused by heavy rains. More often, they occur because there is sufficient rainfall for irrigated farmland between the Hume Dam and the Barmah Forest, consequently river diverters do not choose to take allocated water, Lake Mulwala ( Yarrawonga Weir ) also has inadequate storage, resulting in high level river flows referred to as "rainfall rejections".

These unseasonal high level river flows result in unseasonal flooding in the Barmah-Millewa Forest, which has a significant effect on forest and wetland ecology, degrading wetlands by interfering with the natural drying-out phase and by disrupting nutrient cycling processes. In recent years, unseasonal flooding is being controlled, and "environmental water" is being released to offset some of the detrimental effects of river regulation on the ecosystems along the lower reaches of the Murray River. Management of environmental water supplied through the Murray-Darling basin to the Barmah–Millewa Forest is complex, and mainly under the control of the Murray-Darling Basin Authority. In Victoria the Victorian Environmental Water Holder also manages environmental water allocations.

The supply of environmental water to Barmah Forest aims to:

- Enhance the health of river red gum communities and aquatic vegetation in the wetlands and watercourses and on the floodplain, and promote the growth of floodplain marsh vegetation communities, particularly the extent of Moira grass

- Maintain or increase available habitat for frogs and turtles

- Provide feeding and nesting habitat for colonial nesting waterbirds

- Provide native fish with access to a range of floodplain, riverine and refuge habitats including by delivering variable flows that promote spawning

- Enable nutrient cycling (particularly carbon) between the floodplain and river through connectivity Provide early-season flushing of the lower floodplain to cycle nutrients during cooler conditions and reduce the risk of poor water quality events in summer

The Barmah National Park is a river red gum forest, consisting of an upper storey of red gums, no shrub layer or middle storey, and a ground storey of native grasses, sedges and rushes. The edges of the forest merge into a eucalypt-box woodland.

The park is a large flood plain and wetland area, with flooding of the Murray River occurring sporadically, both naturally and due to flow regulation of the river.

Threatened species of flora found in Barmah National Park may be listed under the DELWP Advisory List of Rare or Threatened Plants in Victoria, the Flora and Fauna Guarantee Act 1988 (FFG), or the Environment Protection and Biodiversity Conservation Act 1999 (EBPC). Many listed plant species do not have Wikipedia pages, more information can be found on the Vicflora database.

Threatened species of native fauna occurring in Barmah National Park may be listed under the DELWP Advisory List of Threatened Vertebrate Fauna, the Flora and Fauna Guarantee Act 1988 (FFG), or the Environment Protection and Biodiversity Conservation Act 1999 (EBPC).