Modelling the Local Ecological Outcomes of Basin Scale Water Planning

AbstractIn 2011, the Australian government proposed the Murray-Darling Basin Plan to promote a healthy working river system. The proposed Plan seeks to limit surface water (consumptive) use to 10873 GL/year on a long-term average. The controversy prompted by this proposed reduction in extractive allocations has underscored the need for transparent and objective modelling of ecological benefits. In this paper, we investigate the likely ecological outcomes of the proposed plan for the Macquarie Marshes, a Ramsar-listed wetland in the Murray-Darling Basin, using a decision support system (DSS). The DSS uses a detailed wetland hydrological model to drive ecological responses for a range of important species. Our hydrological modelling results indicate that the proposed plan would increase inundation extent significantly with a 33% increase for the median when compared with the current water sharing plan. The increase in inundation extent would improve the hydrologic condition in most wetlands. Our ecological modelling results show that the improved hydrology would enhance the wetland quality for a range of vegetation and water-bird species, although benefits are not distributed evenly across the wetlands. For a number of species, some wetlands within the marshes have habitat quality scores matching the predevelopment scenario and benefits of additional environmental water allocation were noticeable when modelled for a prolonged drought period.Key Words: Water planningecological impactsfloodplain ecologydecision support systemswater allocation Additional informationNotes on contributorsL WenDr Li Wen is a senior environmental scientist in the New South Wales Office of Environment and Heritage. He has had an extensive career in wetland ecology, specialising in hydrodynamic/hydrological modelling, hydraulic-ecology relationship, and decision support systems. His main research interest is modelling the long-term impacts of water resource management strategies on the ecology of floodplain wetlands. Prior to this, Li worked as aquatic ecologist in South Australia Department of Water, Land and Biodiversity Conservation, responsible for ecological restoration projects in the Lower River Murray.K RogersDr Kerrylee Rogers is an ARC Future Fellow within the School of Earth and Environmental Science at the University of Wollongong. Kerrylee's research focuses on the response of aquatic ecosystems to environmental variables, with particular attention given to aquatic ecosystems in southeastern Australia and projected responses to climate change. Her research takes a multidisciplinary approach, employing field work on condition and health of aquatic vegetation, laboratory analyses of sediment accumulation, and spatial and statistical analyses to describe relationships between the distribution of biota and environmental variables. Kerrylee previously worked as a research scientist with the NSW Office of Environment and Heritage and has some consulting experience.N SaintilanDr Neil Saintilan is a Senior Principal Research Scientist in the NSW Office of Environment and Heritage, where he is also Senior Team Leader, Water and Wetlands in Science Division. His research interests include wetland hydrology, ecology and responses to climate change. Prior to this Neil worked as an academic, and is an Honorary Professorial Fellow of the University of Wollongong. He is the recipient of the NSW Science and Engineering Prize for Public Sector Science and Engineering, the Fellow Award of the Society of Wetland Scientists, and the Fulbright Fellowship in Climate Change and Clean Energy.

Topic: Water resources management and optimization
Subfield: Ocean Engineering
Field: Engineering
Domain: Physical Sciences