An integrated model to examine the effects of Sustainable Diversion Limits: A case study in the Lower Campaspe catchment

Setting limits for consumptive water extraction from the Murray-Darling Basin, known as Sustainable Diversion Limits (SDLs), is a key feature of recent water reforms. The ecological and socioeconomic impacts of SDLs have been assessed for the entire Murray-Darling Basin. However, there is still little understanding of how these limits will play out at the catchment scale and at more localised levels. To build this understanding, the SDLs (estimates and rules) need to be examined using a multidisciplinary framework that includes water management policies, climate change projections, the nature of surface watergroundwater systems, and water-dependent economic and ecological systems. This paper presents an ongoing collaborative project between the research team in the National Centre for Groundwater Research and Training (NCGRT), Victorian Department of Environment and Primary Industries, North Central Catchment Management Authority and Goulburn-Murray Water. It examines the effects of implementing the SDLs for the Lower Campaspe catchment in Victoria in terms of tradeoffs between the profitability of agricultural production and ecosystem response, especially groundwater dependent ecosystems. The model under development is also intended to be flexible enough to investigate adaptation options for landholders and water policy initiatives. In undertaking such an integrated assessment project, the research team brings together researchers from multiple disciplines, including hydrology, hydrogeology, ecology, resource economics, social science and systems science. The project has applied an integrated modelling approach which focuses on working closely with project stakeholders to identify modelling questions, share results and seek feedback. Our aim is to develop an integrated modelling framework that can be reapplied in other catchments to address stakeholders’ questions and concerns with regard to the implementation of the SDLs at the local level. In this paper, we give a brief overview of the design of the integrated model under development, and its key components and interactions.