Murray River Wetlands Management and Water Recovery Initiative: Fish communities, aquatic habitats and water quality at sites prioritised for water recovery works
Snake Island Lagoon – one of the wetlands ear-marked by DNR for water recovery works.
Inflows to the water storages in the southern Murray-Darling Basin are the lowest on record and during 2006, inflows to the Murray River were only 60% of the previous minimum. If these conditions continue throughout 2007, or if inflows are in the lowest 1% per cent of years on record, special measures will be needed to supply the critical water needs of many towns, particular Adelaide. Contingency plans have been developed by the NSW Department of Water and Energy (DWE) to meet the critical demands of urban areas and towns, and other households relying on the water supply systems of the southern Murray-Darling Basin. These plans include the elimination of water lost through evaporation from large permanently inundated wetlands along the Murray River. DWE has identified 30 wetlands where over 1 GL of water could be recovered. The proposal is to construct temporary block banks or regulators at each wetland inlet to disconnect the wetland and prevent water transfer from the river. After construction, water from the wetlands may then be pumped back into the river.
Proposed disconnections are subject to State and Federal legislation and need to address potential ecological impacts of the works, including their impact on threatened species or populations of fish, or the endangered ecological community of the Lower Murray River. The fish faunas occurring within wetland systems in the Murray-Darling Basin are poorly understood, as most survey effort has focused on river channels. In most cases, no data on fish community composition within specific wetlands exists. Given its importance in the decision making process regarding wetland management, fish community data is urgently required. NSW DPI will sample fish communities present in each of the wetlands where works have been proposed to identify whether any populations of threatened fishes are present. NSW DPI will then assist DWE by identifying any potential impacts that may arise as a result of the proposed works and recommend measures to ameliorate any potential impacts that may occur.
Rapidly identify and quantify the fishery values of wetlands prioritised for construction of temporary regulating structures within wetlands of the lower Murray Region. This will be achieved by:
- Sampling fish communities within prioritised wetlands.
- Generating a list of fish species detected, including identification of any species listed as threatened or of conservation significance.
- Providing advice as to whether the site should be eliminated from further consideration due to the importance of the site for threatened fish species and/or whether additional sampling should be undertaken in adjacent river reaches to determine if the specie(s) in question exists outside the wetland.
- NSW Department of Primary Industries
- NSW Office of Water
Dr Dean Gilligan