The approach of the Modelling cross-cutting Theme will give us tools to expand our understanding of individual species at specific locations, and at specific times, into a holistic assessment of the ecological response of the Basin to environmental watering. It will provide the necessary building blocks to create a Basin-wide model of ecological response that will be a powerful tool in quantifying the overall benefit of Commonwealth environmental water in the Murray-Darling Basin.
One of the primary ways in which modelling will assist in the evaluation of Commonwealth environmental water outcomes is by quantifying those outcomes. We already have models of hydrology (water movement), weather and other physical processes for the Murray-Darling Basin. These models enable managers to understand the current physical condition of the Murray-Darling Basin and, importantly, to compare that to the condition that would be expected in the absence of environmental water (a so-called ‘counterfactual’).
While models of many of the physical conditions in the Murray-Darling Basin are well developed, however, there is no single model of ecological response at the Basin scale. Moreover, the effect of environmental water on ecological response depends on a range of environmental factors, in addition to the volume of water, and so can differ at different locations and times. This makes it extremely difficult for managers to create a holistic assessment of the change in ecological condition as a result of environmental watering.
This means that the benefits of Commonwealth environmental watering cannot currently be objectively quantified at the scales of many of the management decisions. Our work will create the architecture for a Basin-wide ecological model that will move us closer to being able to understand the ‘ecological counterfactual’ for the Basin. This will enable managers to quantify the benefits of Commonwealth environmental watering holistically and transparently.