The Lachlan river system has fundamentally changed through the building and operation of dams, and the use of water, mainly for irrigated agriculture. This has changed the flow patterns of the river and has substantially changed the inundation of wetlands. Most of the small and medium sized flow pulses which would have occurred naturally in the river in response to rain in the catchment, no longer occur as flow from these is captured by dams. This means many of the wetlands, billabongs and anabranches get water in them far less frequently than they would have before the dams were built. In addition, floodplain development, and structures on the floodplain affect natural flooding regimes. It also means that less water makes its way to the Great Cumbung Swamp.
Many native species, including fish, birds, and plants depend on certain flow conditions for breeding, dispersal, and reproduction. Changes to the way water moves and is used within the Lachlan river system has markedly altered the character and condition of the rivers, floodplains and wetlands, particularly those at the end of the river system (the terminal wetlands).
Environmental water is used in the Lachlan river system to support the significant ecological values that occur across the catchment, particularly those most affected by changes to flow regimes. Our monitoring focusses on the lower Lachlan river system from Lake Brewster to the Great Cumbung Swamp. Our research is based within the Great Cumbung Swamp which is a priority under the Basin Plan.