Lindsay, Mulcra and Wallpolla Islands: The Living Murray Condition Monitoring
The Living Murray is Australia’s largest long-term river restoration project. The cross-jurisdictional program is a joint initiative of the Australian Government and the governments of New South Wales, Victoria, South Australia and the Australian Capital Territory. The program is a significant investment in the long-term sustainability of the River Murray system and aims to achieve a healthy, working river for the benefit of all Australians.
The Living Murray efforts involve a combination of on-ground works for the delivery of environmental water and a program monitoring the ecological-condition of six icon sites chosen for their ecological and cultural significance. The six icon sites are:
- Barmah-Millewa Forest
- Gunbower and Koondrook-Perricoota Forests
- Hattah Lakes
- Chowilla Floodplain (which include Lindsay–Wallpolla Islands)
- Lower Lakes, Coorong and Murray Mouth
- River Murray channel.
The Lindsay–Wallpolla Islands comprise the Victorian component of the Chowilla Floodplain icon site. The 43 856 ha area of floodplain lies within the Murray–Sunset National Park in the north-west corner of the state, is bordered to the north by the Murray River between locks 6 and 10, and to the south by the Lindsay River, Potterwalkagee Creek and Wallpolla Creek anabranches. The floodplain system consists mostly of watershed floodplain interwoven by a network of permanent and intermittently flowing anabranches, creeks and shallow flood-runners. The islands are interspersed with wetlands of varied ecological character, including some that are listed as nationally important and some of international significance with respect to bilateral migratory bird agreements.
The rich patchwork of terrestrial and aquatic habitats that occur at Lindsay–Wallpolla Islands support a unique suite of biota including rare, endangered and nationally threatened species. The most significant threat to the ecological sustainability of this floodplain system is altered hydrology. Regulation of river flows, through the operation of a series of weirs and upstream storages, has greatly reduced the variability of flows at Lindsay–Wallpolla Islands. The naturally ephemeral system comprises components that are now either permanently inundated or flooded much less frequently. The timing, magnitude and duration of flooding have also markedly changed from natural.
The Living Murray initiative aims to ameliorate the hydrological threats to the ecological health and character of the Lindsay–Wallpolla floodplain through environmental works and measures to reinstate a more natural wetting and drying regime. Environmental works completed as part of the initiative include:
- (i) a regulator with carp screen at Webster’s Lagoon on Lindsay Island
- (ii) a regulator with carp screen at Horseshoe Lagoon on Wallpolla Island
- (iii) twin regulators with carp screens and raised levee at Lake Wallawalla
- (iv) a network of structures at Potterwalkagee Creek on Mulcra Island.
The monitoring and evaluation work inform the optimal operation of these structures for ecological outcomes. The program reports on the influence of hydrology, both natural and managed, on:
- River Red Gum and Black Box communities
- wetland and floodplain vegetation communities
- waterbirds and fish.
This long-term environmental study is important to improve our understanding of how hydrology affects the maintenance of aquatic, riparian and floodplain biota at multiple spatial and temporal scales.
- Murray–Darling Basin Authority [external link]
- Victorian Department of Environment, Land, Water and Planning [external link]
- SA Water [external link]
- Parks Victoria [external link]
- Trust for Nature [external link]